Biology

H.pylori is a spiral shaped gram-negative bacterium found in the mucus lining of the stomach and duodenum. It is motile due to the presence of a sheathed flagella which, together with its spiral morphology, aids in the colonization of the gastric and duodenal mucus (Eaton, Morgan, Krakowka, 1992). It has a cell wall containing lipopolysaccharides (LPSs) which is typical of other gram-negative bacteria. Aside from maintaining physical integrity and function of the cell envelope, the LPSs also afford immunomodulating and immunostimulating properties due to their lipid component known as lipid A. The biological activity of lipid A is though to play an essential role in the pathogenecity of H.Pylori

Enzymes produced by H.pylori  
H.pylori produces the enzyme urease which enables it to survive the highly acidic environment within the gastrum and duodenum. Urease catalyzes the conversion of urea into ammonia and carbamate which in turn increases the local pH thereby protecting H.pylori from gastric acid within the mucosa (Mobley 2001). H.pylori also possess mucinase activity which is thought to aide in the dissolution of the mucosal barrier allowing H.pylori to survive and colonize the thick mucus layer of the upper gastrointestinal tract (ORourke  Bode 2001).

Prevalence of H.pylori infection   
H.pylori infection is a very common infection especially among patients with peptic ulcer disease. In approximately 9 out of 10 cases, peptic ulcers are likely caused by H.pylori infection. Both males and females are affected. Although it is a ubiquitous infection, it is more prevalent in developing countries than in developed countries. This is attributed to the high prevalence of infection in children under 10 years old in developing countries. This is also associated with the low socioeconomic status which increases the risk of H.pylori infection particularly during childhood.due to the poor availability of safe drinking water and the high rate of transmission caused by crowded households with several siblings (Mitchell 2001).

Pathogenesis of H.pylori infection  
The pathogenesis of H.pylori is primarily attributed to its ability to persist in the host where it can cause damage to mucosal tissues. After ingestion, it is able to penetrate the viscid mucosal layer where it causes chronic inflammation. Glandular atrophy follows either due to direct mucosal injury caused by H.pylori or due to the prolonged inflammatory response to H.pylori infection. The loss of mucosal and grandular tissue then leads to ulceration (Dixon 2001).

Gastrointestinal disorders associated with H.pylori infectionChronic gastritis is the common denominator associated with disorders caused by H.pylori infection. These disorders include ulceration, gastric carcinoma and lymphoma. The histologic feature of chronic gastritis encompass chronic inflammation, gastric atrophy and instestinal metaplasia. Intestinal metaplasia refers to the change from gastric epithelium to intestinal epithelium caused by abnormal growth stimulation after repeated mucosal injury (Dixon 2001).

Diagnosis of H.pylori infection 
Previously, the presence of disorders associated with H.pylori infection such as histologic gastritis, peptic ulcer and gastric carcinoma is the first indication suggestive of the infection. However, newer serologic tests such as elevated serum gastrin and pepsinogen levels suggest H.pylori infection (Graham  Qureshi, 2001).
Lifestyle modification for patients with peptic ulcers
   
Patients with peptic ulcer should observe lifestyle changes such as stress reduction, avoidance of excessive alcohol consumption and high fiber diet. The rationale for these changes is to limit gastric acid production and promote ulcer healing.

Oral cancer, found in the oral cavity, can be detected early on. Cancers of the oral cavity are growths that appear on the lips, tongue, gingivae, palate, buccal mucosavestibule, salivary glands, and the floor of the mouth. Majority of these cancers are carcinomas, or tumors that cultivate from unrestrained growth of single cells or clones of cells that are found in the stratified squamous epithelium (Silverman 2001). Most of these cancers are of the squamous cell type, particularly squamous cell carninomas (SCCs). Carcinomas, on the other hand, are already developed tumors because of the non-prevented growth of cells or a group of cells (Silverman 2001).

Oral cancer is one of the most common cancers throughout the world. According to Johnson (1991), most of the cases are those of the squamous cell carcinomas, seen in both men and women in India, Bangladesh and Pakistan, reaching around 30 to 40 percent (Tanimoto 2000). Clearly, it is prevalent in developing countries with the lack of prevention and inattention to health care, it is among the leading causes of death. Moreover, according to the World Health Organization or WHO, most of the cases in these developing cases are among males (Tanimoto 2000)

According to the International Classification of Diseases, oral cancer also affects the pharynx, lips, tongue, salivary glands, gum, floor and other mouth areas. The oral cancer survival rate is one of the lowest in a five-year period (Wong 1996). This survival rate is again lowest as compared with other cancers including skin melanoma, and cancers of the breast, colon and kidney, among others. Oral cancer is cited clinically when there are color alterations or in the texture of the oral mucosa. A biopsy must be undergone once there is confirmed diagnosis of oral cancer (Chairman and Downer 1995).

Citing Sidransky (1995), the malignant cell becomes independent functionally as it continues to develop or mutate. It becomes independent of its environment made of normal oral keratinocytes (Wong 1996). The normal functions of the cell become those of tumor cells, increasing their capacity to propagate in nearby areas or metastasizing.

Previously believed to affect those of the older generation, it has been occurring in the younger age groups due to increasingly excessive use of products over a long period of time. These prompt these malignancies, along with tobacco and other related products.

While traces can be found in persons with a long history of smoking and alcoholism, there is a growing consciousness on oral cancer that is not necessarily associated with tobacco and alcohol abuse (Sciubba 2001). There are also studies that show that the use of smokeless tobacco is connected with risks in oral cancer albeit minimal. It was cited in the Comprehensive Smokeless Tobacco Education Act that smokeless tobacco is still harmful because of its carcinogenic effects (Rodu and Jansson 2004).

In the United States, oral cancers (along with pharyngeal cancers) comprise 3 percent of cancer cases in the US, and the forecast is that these cancers will give birth to 30,100 new cases and lead to 7,800 deaths (Silverman 2001). However, it has become apparent that there have been effects on the quality of life on survival cases, particularly the risk of developing cancers in the head or neck. Though with varying degrees, Silverman (2001) posits that the tendency is greater among smokers.

The cause of the tumor growth is not well comprehended, but pre-malignant states of the oral cancers have been noticed. The white and red spots inside the mouth are widely recognized as pre-malignant or pre cancerous. The tumor can possibly grow due to a series if accumulations of genetic alterations which is also observed in other types of cancers (Tanimoto et al 2000).

However, these cancers become untreatable when they are not diagnosed earlier, which is a poor enough reason given the early recognizable signs. Moreover, the oral cavity is very much examinable in that the appearance or growth of lesions or patches can be detected early on. The previous author also pointed out that when these lesions develop into cancerous ones by the time they are diagnosed, it can be difficult to attest success or effectiveness of the treatments (Tanimoto et al 2000).

The aggressive treatment required to improve cure rates for advanced lesions is associated with increased morbidity (Sciubba 2001). Further, Sciubba (2001) points out the disappointing fact that while oral cancers are easily examined  about 90 seconds  there have been few specialists who administer such examinations. Coupled by the lack of an massive awareness program, he states that the analysis on oral cancers for the past decades has not been made better.

Aside from the lack of knowledge, the late detection of such cases or the detection of advance cancerous lesions is attributed to the inaccessibility of reliable health care. Much effort should be geared towards enhancing the detection of precancerous or pre-malignant lesions, since herein lies the early prevention, as stressed by the previous author (Sciubba 2001).

Moreover, since the development of oral cancers can be detected at an early stage, the role of dental examinations is critical. The history of dental visits can very much form an integral part of detection. Thus, the dentist must take into account that risks are posed by patients and that they must act accordingly in these phases. Thus, by having a clear account of a patients oral history through examinations, the dentist can increase the likelihood of prevention (Sciubba 2001).

The same author argues that if an analysis of an advanced and much serious case is only later established, a less effective result is expected. Specialists or practitioners can largely affect the outcome and the patients quality of life when oral mucosal alterations are confronted representing SCCs in patients.

Risk Factors
Oral cancers develop due to certain risk factors that are generally believed to be a cause determinant. As already mentioned, excessive tobacco use and its related products and alcohol consumption are primary of these. In the United States, these factors are responsible for 75 percent of the cases. The doctor-researcher also names the use of marijuana as potentially harmful, as well as viruses like the human papillomavirus (HPV). However, a healthy diet with a considerable amount of fruits and vegetables is seen to decrease the aforementioned risk factors that develop oral cancers (Silverman 2001).

The rising role of the HPV in oral cancers has been observed in India. In a study, there has been 20 to 50 percent detection rate of HPV in oral carcinomas and thus the high positive rate is acknowledged to be a factor in the development of tumors in the head and neck (N. M. Chocolatewala and Chaturvedi 2009).
Oral cancers also tend to develop with age. There is a higher risk factor for those who are aged 45 years and above. The professorresearcher explains that such incidents are correlated with age because cellular biological alterations are a result of exposure to external harmful elements and pollutants, viruses, bad nutrition, and even unwanted elements in food products. As mentioned previously, bad habits which include heavy smoking and alcoholism are risk factors. Recently however, there are trends which show emerging cases in younger age groups, mostly young adults from 20 to 30 years of age, not necessarily related to the risk factors of tobacco and alcohol use (Silverman 2001).

In the results given by the National Cancer Institutes Surveillance, Epidemiology, and Ends Results (SEER), oral cancers have been noted recently in the time period from 1994 to 1998. Between this time, men are more likely hit than women, while in the race aspect, Blacks register higher incidence than whites. In the said study period, it has also been found that most of the cases are found in the tongue. Citing his previous study, Silverman (2001) comparing national data between the years 1973 and 1984 with data between the period of 1985 and 1996, shows that there is an increase in oral cancers that are found in the tongue (Silverman 2001).

Data coming from the SEER showed that there is a higher mortality rate in men than women in the US due to the said cancer. It was also found that survival rates for cancers found on the base of the tongue are low compared to that which are found in the visible tongue portion. This h is easily explained by the fact that said carcinomas are less or later diagnosed. Further, the low occurrence of cancers in the gingival and alveolar areas points out that there is no relation between those who wear dentures and development of malignant cancer cells (Silverman 2001).

Race and ethnicity are also risk factors. Genetic configurations and predispositions, even socio-economic factors, such as accessibility to quality medical care and lack of public awareness are contributory. The oral cavity is the fourth most cancer-prone area among black men in the US. The study which also covers various states in the US, suggests that the oral cavity is still the most common place of cancers, and also in black men. In California for instance, following blacks are non-Hispanic, Asians, and Hispanics, which are similar to national incidence rates and mortality rates (Silverman 2001).

Oral cancer has also been on the rise in the United Kingdom, at 25 percent in the past ten years according to an article in Health Education (n.d.). Again, the main culprits have been our usual suspects  tobacco from smoking and alcohol abuse. However, in the UK, alcoholism is much more prevalent than smoking. The same article pointed out lack of public awareness, as oral cancers are not much publicized or tackled, despite its being a silent killer. In fact, there are more deaths that are caused by oral cancers than cervical or even testicular cancers added up.

In a research paper detailing the salient risk factors, Sciubba (2001) identifies tobacco use, alcohol consumption, diet and lifestyle. The research solidifies what have been previously explained on oral cancers risk factors zeroing in on these four culprits. The effects of excessive smoking and tobacco use have been common knowledge. Because of its potential impact and direct contribution to the development of oral cancers, the information should be known at the very start particularly in dental examinations. The use of tobacco is preponderant in other countries outside the United States particularly developing ones. Use usually refers to such practices as chewing betel leaf, tobacco and similar products, though smoking tobacco is still believed to be most harmful because of its many complications not just orally. Further, there has been a strong connection between the growth of pre-malignant oral cancers in the form of erythroplakia and tobacco chewing coupled with alcohol consumption (Sciubba 2001).

The same professor-researcher also links the strong relation of alcoholic consumption to the development of oral cancer, particularly with the combination of tobacco use or smoking. There is what is called a synergisticeffect with these two risk factors that trigger oral cancer development. There is believed to be a chemical alteration of elements both found in the said materials that complicate or trigger risk of oral cancer (Sciubba 2001).

Because there is increasing awareness on having a healthy lifestyle, diet is also considered to be influential in the development of oral cancers or even in its pre-malignant stage. However, if a diet which contains natural carotenoid compounds and vitamins A, C and E is maintained this can offer protection to the development of cancer (Sciubba 2001). In relation to diet, lifestyle is also integral in the determination of the entire risk factor in the development of oral cancers. Lifestyle is strongly linked to the usage of such prohibited substances that are risk factors of oral cancer, including tobacco and alcohol. Doctors would refer to the patients history or lifestyle to determine such risk factors that are prevalent. Naturally, in these examinations, the detection of contributory risk factors would somehow abate the development of oral cancers (Sciubba 2001).

Dental Problems as Early Risk Factors
At the onset, one of the very apparent triggers of the development of oral cancers is poor nutritional health and bad diet. Evidently, there is a relationship with our eating habits as well as our oral health. What we consume may also pose a risk (__, Nutrition and Food Science, n.d.).
In a report from the British Nutrition Foundation on Oral Health, participants of a conference they conducted assessed the relationships of diet and dental health in various age groups from children and older people with tooth defects including oral cancers (__, Nutrition and Food Science, n.d.).

As Edgar (n.d.) in the aforementioned conference paper stated, tooth cavities is a result of the interaction of three factors  susceptible tooth tissues, oral bacteria in the form of dental plaque and dietary intake of fermentable carbohydrate, which are sugars  for a certain period of time. Cavities are formed because of the conversion of acid by bacteria, thus, the proponent recommends the restriction of sugar intake. Further, such should be consumed at meal times and not in between meals, because these remain stagnant (__, Nutrition and Food Science, n.d.).

In a study in the UK, dental problems are prevalent among individuals over 65 years. Further, as cited by one professor from the University of Newcastle, surveys conducted nationwide in the years 1968, 1978 and 1988 reveal a slowdown in the number of people without natural teeth as another professor Walls said in the same conference paper report (n.d.). Moreover, this is very much the case when there are fewer dental visits. As pointed out earlier, detection of pre-malignant or early signs of cancers which can be brought about by these dental defects can be traced in the early examinations by the doctor or dentist.
If detected on an early stage, majority of around 75 percent of oral cancers can be avoided, which is an idea that the article also supported. Thus if there is a lifestyle change, if a person lessens or even avoids excessive drinking and smoking for over a long period of time, oral cancer cases can also be reduced drastically. Public awareness may be addressed by having effective, tangible materials coming from health practitioners themselves since they have first-hand encounters with patients (Silverman 2001).

Cost-Effective Screening for Oral Cancers
A study was conducted regarding the cost-effectiveness of oral cancer screening programs, using a decision analysis model. Data were sourced from two hospitals providing information on the costs required. Hypothetical screening programs were conducted from among a number of primary care settings and participants with a population of over 40 years (Speight 2006). The study points out that opportunistic screening for oral cancer may be cost effective. In addition, it recommends that this be done by general dental practitioners that have already gained expertise in mouth examinations, which is a practical approach (Speight 2006).

Speight (2006) further notes that the screening targets those within 40 to 60 years old for effectiveness. However, there is also uncertainty especially on the rate of malignant development and disease progression. Thus, studies that address or are geared towards determining malignant development as well as the progression rate of oral cancers are encouraged. However, a planned and controlled trial may be beneficial because the wait and see attitude is not highly encouraged, thus before arriving at a decision, a relevant data gathered (Speight et al 2006).

Molecular Biology
There is a poor forecast for patients who have oral malignancies because of the five-year survival rate (Shetty 2003). Further, the possibility of recurrences can become a hindrance to a progressive treatment for the development of oral cancers. Science, particularly through molecular epidemiology, is expected to devise an approach for prevention, moreover the avoidance of pre-cancerous lesions, and is expected to yield surgical techniques and forecasting.

Carcinogenesis is a difficult, multi-layered process wherein genetic activities within a cell are altered whether quantitatively or qualitatively (Wong, Todd, Tsuji and Donoff 1996). This approach is being looked into because the dependence on genetic basis of cancer is well-known. The signal transduction pathways of cells regulate the oral keratinocyte biology (Wong et al 1996).

The author also stressed the genetic aspects of oral cancer transformation as the result of gene alteration or intervention, and that this change may course through different genetic pathways. Eventually, the process can lead to a better understanding of the disease process itself. As suggested by Knudson and Nowell, carcinomas develop because of the buildup of many genetic activities that affect a cell, which may be a form of mutation or alterations (Shetty 2003). As the researchers pointed out, cancer results from a buildup of the changes in these cellular pathways, which may occur at any level of the pathway. Citing the abovementioned authors, up to six (6) mutations are needed to change a normal cell to become a malignant cell (Wong et al 1996). The researchers note that research on oral cancer pales in comparison to other cancer researches. Efforts should be aimed at enhancing diagnosis of pre-malignant epithelium and that the area of research activities targeted at lessening the occurrence and heightening the early diagnosis and cure of oral cancer covers basic science laboratory research to human clinical trials (Wong et al 1996).

Molecular biology analysis, as pointed out in previous paragraph on this section, is an important part of examination as well as other genetic technologies and techniques. Further, the mentioned researchers strongly recommend a cancer research program that incorporates the varied modes of technology in investigation but are somehow similarly relevant. Further, they suggest that it is vital to form a collaboration of scientists and specialists on this field towards the same aim of investigating further oral cancer research (Wong et al 1996).
Using molecular biology as an approach will amplify the likelihood of detecting high-risk lesions, particularly in the scientific field of molecular epidemiology. Second primary tumors, classified into those that are detected simultaneously (synchronous) and those that are found out only after a certain duration of time (metachronous), are expounded based on genetics (Shetty 2003).

Studies also point out inherent and adaptive immune effectors in tumor elimination in which mounting successful anti-tumor responses are recognized while on the other hand, much evidence shows that immune responses should hold back or diminish transformed cells in many cancer patients, including oral cancer (Jewett, Head and Cacalano 2006).

As we understand more anti-tumor responses and cancers, we recognize the interaction between immune effectors and tumor cells. In immunoediting, we learn that these immune effectors shape tumor cells, select cancers with lessened immunogenicity and enhanced capacity to actively induce immunosuppression (Jewett, Head and Cacalano 2006). A multi-disciplinary approach in oral cancer management has been noted especially with advances in molecular biology. Some of the emerging challenges include enhancing rates of therapy, lessening morbidity of treatment and the use of molecular indicators to foresee tumor behavior thus appropriating accurate treatment (Ord and Blanchaert 2001).
DNA Hybridization

The DNA hybridization array is used to analyze the gene expression in biologic systems (Todd  Wong 2002). This technology been used to study cellular activities particularly in physiologic responses to environmental factors in an intact organism. Since DNA is being analyzed, nucleic acids from samples are examined. Further, the researcher states that this approach has been implemented in the research of cancer for improved comprehension, as well as better diagnosis and cure of malignancies in humans (Todd  Wong 2002).

With the relevance of this technology, it is now being used in cancer therapeutic research through these two strategies biomarker identification and drug discovery. As mentioned, this holds a promising result in the case for improved diagnoses and even in the treatment of cancer, particularly the detection of pre-malignant formations of lesions and identification of the malignancy. Further, the DNA hybridization array technology will see its importance in the area of drug development because it identifies targets in preventing the development of oral cancers (Todd and Wong 2002).

Todd and Wong (2002), explained that DNA hybridization arrays were used to identify gene clusters that would predict the responsiveness of oral cancer to radiation and pointed out that in the aforementioned study the radiation resistance has decreased tumor size with continuous exposure treatment for six (6) weeks. Radiation responsiveness was also predicted. Further, the researchers planned to enhance the gene expression profile to establish a more correct means of patient identification with non-responsive oral cancers.

Health and Nutrition
The use of vitamin A analogs which include beta-carotene, has been studied closely particularly in the progress of examinations being carried out using this approach that could considerably contribute to the avoidance of recurrence of new primary oral tumors. Similar protective properties of other food elements are also being looked into (Chairman and Downer 1995).

Thus, the researchers also urged changes in lifestyle particularly on those risk factors, through promoting healthy lifestyle and its vital importance in the prevention of oral cancer and even in its pre-malignant phase. However, the authors also point out the cost-benefits of interventions (Chairman and Downer 1995).
Bionutrition emphasizes the importance and relationships of diet, nutrient consumption, genetics, and surrounding environment, taking into account the functions of these nutrients and other food elements in a healthy lifestyle and in disease prevention (Enwonwu and Meeks 1995). The study also supports that the common culprits in increasing the risk of oral cancers, excessive tobacco use and alcohol consumption. Around 80 to 90 percent of human cancers are environmentally-triggered or caused by factors in the environment, and changes in diet increase the likelihood of reducing deaths by around 35 percent.
In a research review by Chairman and Downer (1995), they mentioned a study conducted concerning the mass screening of oral cancer and pre-cancer in Japan, particularly in Aichi Prefecture in Tokoname City. The procedures for the study are intensive which require primary preventive education to targeted population, referring particularly to mails that invite target participants for an oral examination. The patients who underwent examinations were also recommended for diagnosis for confirmation of patients who have the disease. These procedures were stringent since these were administered through the supervision of the World Health Organization (WHO).

The said study stressed on the importance of health promotions, targeting populations and ensuring their compliance, and establishing screening standards. The study also ensured that specialists administer the procedures using advanced technology, and further, controlled trials. The study also showed that the lessening of tobacco and alcohol use contribute to the slowdown of oral cancer cases. Moreover, early diagnoses reduce the likelihood of oral cancers and make it preventable (Chairman and Downer 1995).
In the same research review, the focus of prevention of oral cancer at the primary level is the prohibition of use of tobacco and alcohol, while recognizing white and red changes in the oral cavity as oral cancer precedents are aimed as a secondary prevention. There is good prognosis if oral cancer is cured at its early stage. Since the first clinical signals of oral cancer are red and white changes in the oral cavity, earlier diagnosis is strongly recommended. The authors also did not recommend exfoliative procedures because of likelihood for negative results.

However, for especially high-risk cases, a cold-knife surgery or laser surgery is preferred. If results reveal a presence of distinct epithelial dysplasia, treatment is strongly urged (Chairman and Downer 1995). Further, they also recommended a systematic dispensation of substances like beta-carotene and isoretinoin. Patients must continue with follow-up examinations and treatment because of the high risk of developing second and third primaries in respiratory and upper alimentary tracts.

Despite its traces being recognizable, as it can be found immediately in the oral cavity, signs have been neglected this making oral cancer a serious and fatal disease if not prevented. The appearance of red and white lesions or patches can already be a case of oral cancer. It can affect the patients quality of life because of the development of further complications if malignancies remain untreated. Treatment in these instances may already be costly. Prevention of the cancer at its pre-malignant phase should be prioritized. These are often detected during dental visits and oral examinations, thus, the role of the dentist is also crucial.
There is also greater need for public awareness. An information mechanism that would also target patients and those already with positive results is highly encouraged. Since the main risk factors include excessive alcohol and tobacco use (smoking and smokeless tobacco), health care professionals must recognize the importance of a healthy lifestyle, as well as a good diet, especially since nutrients can also help lessen oral cancer probability, e.g. beta-carotene.

Oral cancer is a serious disease considering there is a five-year survival rate among researches and studies undergone on the disease. Dentists and health care practitioners thus have a crucial role in ensuring that patients have regular and comprehensive examinations. Further, scientific research have shown the importance of molecular biology or epidemiology in advancing better treatment and curative measures of oral cancer, thus encouraging further engagements in research.

Cystic fibrosis, also known in medical terms as mucoviscidosis is a genetically acquired (hereditary) disease common people of Caucasian and Jewish descent (Roberts, 2003). It affects glands that aid inn waste secretion in the entire body to bring about steady progressive disability and eventual death (Davis, 1993). Children who acquire cystic fibrosis are at a risk of facing an early death. The body organs that are most often affected are the lungs, liver, sinuses and the pancreas.  The sex organs and any other glands that secrete mucus and other body fluids are also affected. Cystic fibrosis affects the body by disabling the production of mucus that lubricates body tissue and supports metabolic processes.
An overview of cystic fibrosis
  
 In normal body operations, mucus is produced on the linings of most bodily tissues to keep them moist because the drying up of the tissues causes irritation, making them prone to infections (Murphy, Schubert, 2005). Under normal circumstances, mucus secreted is slippery and watery but if a person has cystic fibrosis, mucus produced is thick and very sticky. It then builds up and blocks the passage of air in the lungs and causes congestion in other body organs creating an environment conducive for the accumulation and multiplication of bacteria (Sharma, 2009). The resultant repeated infections severely damage the lungs in the long run. In the liver and pancreas, this sticky mucus blocks the tubes and ducts that from the passages of enzymes produced here and also the waste products of metabolism.
  
 The pancreas produces enzymes that are required for the digestive process in the small intestines. Due to the blockages caused by thicker-than-normal mucus, these vital enzymes cannot reach the small intestines (Roberts, 2003). Therefore a patient of cystic fibrosis exhibits deficiency of vital nutritional entities like vitamins and proteins, becoming severely malnourished. Indigestion also occurs because of non-exhaustive digestion leading to constipation, the excretion of bulky stool and the accumulation of gases in the intestines.
   
Cystic fibrosis causes the patient to excrete very salty sweat therefore losing a lot of minerals salts in the process (Sharma, 2009). When the natural balance of salts in the blood and other body fluids is upset, there results a number of serious health and metabolic anomalies. Dehydration results due to the body losing more fluids because of the decreased salt concentration leading to increased heartbeat rates, fatigue, low blood pressure, stroke and even death.

Diagnosing and monitoring cystic fibrosis
Cystic fibrosis is a hereditary disease, therefore for babies born in families with a history of the disease, it is recommended that they be screened at birth and be subjected to genetic testing and analysis to establish if they have the condition (Murphy, Schubert, 2005). Additionally, testing of the sweat is done. Newborns with the condition, once screened at birth, show a higher concentration of the hormone immunoreactive trypsinogen. Once the level of this hormone is abnormal, the child is then subjected to a salt test to confirm the cystic fibrosis diagnosis. The level of immunoreactive trypsinogen can be higher than usual in individuals with a single mutation on the gene that causes cystic fibrosis called the CFTR gene, or where this gene is normal but double (Roberts, 2006). In such cases, a subject will falsely test positive, which is why the salt test is necessary to confirm the diagnosis.
   
The salt test involves rubbing a small amount a chemical called pilocarpine onto the person under examination to stimulate sweat production after an electrode has been attached on the arm or leg where the chemical has been applied. Sweat is then collected for analysis to test whether it has abnormally higher than normal concentrations of sodium and chloride ions. Besides the salt test, many other tests are usually carried out to determine whether the patient really has cystic fibrosis. X-ray scans are done on the lungs and the other internal organs to examine any signs of thick mucus accumulation, inflammation and damage (Davis, 1993). Sputum samples are usually examined also to determine the types of secondary infections that may have occurred so that they can be treated. There is also a need for breathing tests to investigate how affected the pulmonary system is and how well it is functioning.
   
The symptoms of cystic fibrosis vary from person to person and time to time and so does the severity. Some patient may develop severe indigestive effects and inhibition of lung function at a very early age while others may just suffer mild reactions or none until they become adults (Sharma, 2009). Lung function becomes affected and begins to deteriorate from early childhood and could become adversely affected causing difficulty in breathing as a matter of fact it is lung failure that causes most deaths related to cystic fibrosis. However, as medical solutions to combat the disease become more advanced, most cystic fibrosis victims are living into their forties and even fifties.

Treatment and management of cystic fibrosis  
As is the case with most hereditary diseases, there is still no cure for cystic fibrosis. It is just that as medical technology has been advancing rapidly, treatments have become more effective. The objective of remedial measures against this disease are aimed at preventing or managing infections occurring in the lungs , to loosen and expel the thick mucus retained in the lungs and other internal organs and to unblock the small intestines (Roberts, 2003). To combat malnourishment caused by an inefficient digestive system, secondary measures are adopted to supplement the nutritional requirements of the patient.
   
People having cystic fibrosis have recurrent infections in the lungs. Depending on the bacterial strain involved and the severity of the infection, the appropriate antibiotics are prescribed to the patient. Because of congestion in the lungs, percussions (Chest Physical Therapy) are performed several times per day. It involves pounding the patients chest and backside repeatedly so that the sticky mucus lodged in the lungs and breathing tubes can bee loosened up and coughed out (Davis, 1993). The patient should be lying on his or her stomach so that gravity can aid in the expulsion of the mucus. In addition to these, people with cystic fibrosis are advised to exercise regularly to strengthen their respiratory system.
   
As lung function and tolerance to physical exercises declines, the only option left for patients is to get a lung transplant (Murphy, Schubert, 2005). In ordinary transplantation routines, patients usually get a single lung, but for patients of cystic fibrosis, it becomes necessary to replace both lungs as the lung left could have infectious bacteria that could infect the new lung. It may be necessary to also give the patient a new liver andor pancreas to minimize the chances of getting liver disease and diabetes. Gene therapy is still being touted as a possible cure for this disease, whereby a healthy gene is placed on the mutated genes.

There are animals that undergo a specific phase of transformation called metamorphosis. Animals like butterflies, frogs, newts and mosquitoes all experience metamorphosis before they reach the imago phase of their life. Metamorphosis is associated with the different stages in life before coming out in adult form. One of the significant associations of metamorphosis is the adaptive changes incur in the organism in the way the organism interacts with its environment. The environmental cues play an important role in the metamorphosis of some organisms. The environmental cues trigger or send a message to hormones that yield to metamorphosis. The bull frog is an animal that undergo metamorphosis and the environmental cues as well as the genetic control are responsible for its development. The genetic control is the turning on and transcription of genes that incur changes in the gene expression which causes the metamorphosis in all animals. The paper aims to evaluate the significant adaptive changes and the genetic control in the development and metamorphosis of bull frogs.

Genetic Control and Metamorphosis
All of the cells in the body are composed of genes, which is made up of a set of instructions for making proteins. The creation of a protein from its gene is called gene expression (Saltsman, 2010). The gene expression is capable of genetic control in development of all organisms. In the case of metamorphosis of most amphibians and insects, the initiation and completion of metamorphosis id under the obligatory hormonal control which distinguishes it from other hormone-dependent late developmental stages. The hormone serves to trigger a predetermined programme of developmental changes in order to prepare the embryo for an environment suitable for adult life. The hormone does not direct the cell to acquire different characters but allows already differentiated but immature cells to acquire adult structures and functions (Khanna  Yadav, 2005).   

The role of hormones in organisms is very important. In organisms undergoing metamorphosis, the hormones play a vital role in carrying out the biological process of change in the bodys structure and function, which is accompanied by cell growth and differentiation. Some species of insects, cnidarians, crustaceans, amphibians, tunicates, echinoderms and mollusks undergo metamorphosis. Metamorphosis is any developmental change in an animals structure that is accompanied of changes in the physiological, behavioral and biochemical aspects. The morphological changes in an organism in the internal and external facets of an organism takes place in a short span of time and is triggered by a combination of external and internal cues. The extent of morphological changes ranges differently among the species. Even though the changes in the metamorphosing organism are very slight, metamorphosis sometimes brings considerable changes in the habitat and lifestyle of the organism (Metamorphosis, 2010).
   
A metamorphosing organism may undergo two paths of development, which are the direct and indirect development. Direct development or often referred to as simple metamorphosis or incomplete metamorphosis is not associated with drastic changes in the physical aspects of the organism. The young often resembles its adult form. Crickets and grasshoppers undergo this type of metamorphosis. Indirect development or complete metamorphosis, on the other hand, is the transformation of organisms that is associated with drastic physical changes. The adult form no longer has the traces of its young form. The larva is completely different from the imago and they often occupy different habitat or niches (McDarby, 2010). Organisms undergoing complete metamorphosis are often characterized by different life stages from egg to larva to pupa and to adult form. Butterflies and frogs are some of the examples of organisms that undergo complete metamorphosis.

Animals that Undergo Metamorphosis
Insects
Some insects undergo metamorphosis before it becomes an adult. Metamorphosis in insects often proceeds in distinct stages that start with larval stage then optionally passing through pupa stage before becoming fully an adult or imago. The stages differ among the insects and the distinction of the stages depends on the nature of metamorphosis. There are two types of metamorphosis in insects which are hemimetabolism and holometabolism. In hemimetabolism, the development of the larva often proceeds in repeated stages of growth and ecdysis or molting. The juvenile form of the organism resembles its adult form and if the adult form has wings, the young lack wings. The main difference between the juvenile and adult form of an insect undergoing this type of metamorphosis is the body proportion and the number of segments. In holometabolism, on the other hand, the larva largely differs from the adult. Insects that undergo holometabolism often undergo the inactive state called pupa or chrysalis before emerging as adults. During the pupa stage, the insect will excrete juices that aim to destroy the larvas body and leave a few cells intact. These cells will grow as the adult form of the insect.
   
Metamorphosis has benefits to the organisms undergoing the process, especially to its adaptation in the environment. Metamorphosis is associated with changes in the way the organism interacts with its environment. In insects, the larva and the imago eat very different foods. The larva has different physical built compared to its adult form. It has unique structures and organs that do not occur in the adult form. A larvas diet can be considerably different from the adults. Thus, the adults and larvae do not have to compete for the same food, which is a limiting resource in the environment. There is a reduced competition in the food sources. The larvae are often adapted to a different environment and by living in two distinct environments the larvae are given shelter from the predator and reduce the competition for resources with the adult population (Metamorphosis  General Features, 2010).
   
Amphibians
The typical development of amphibians starts with eggs that are often laid in the water. The offspring are adapted in the aquatic lifestyle. Frogs, toads and newts are hatched from eggs as larvae with external gills. The specific stages are dependent on the threshold values for the different tissues. Because most of the embryonic development occur independently, the tissues and organs is subjected to a lot of adaptations due to specific ecological circumstances. After the metamorphosis, these organs will die controlled by cell death called apoptosis.
   
In frogs, the external gills and gill sac were formed after they were hatched in eggs. The pace of metamorphosis is really fast and the front and hind legs are visible a few days later. The tadpoles grow in a vegetarian diet due to its environment which is aqueous. Quick and immense changes occur when the frog changes completely. The unused organs and tissues which adapted in the tadpoles environment are reabsorbed. New tissues and organs developed for the adaptation of the adult form of a frog.
   
The adaptive changes in the metamorphosis of tadpoles to frogs render significance to the organism. The young and the adult form of frogs live in two distinct environments and adapted to the mechanisms of their environments. The two also has completely different diet as the tadpoles are herbivore and the frogs become predators of insects. By living in the aquatic environment, the larvae are given shelter and reduce food competition with the adult population.
Environmental Cues for Metamorphosis
   
Insects
Not all species of insects undergo metamorphosis. Metamorphosis in insects is often associated with wing development. It was discovered that PTTH, a brain-produced hormone triggers the metamorphosis in insects by acting like a key fitting in a lock. PTTH is a neuropeptide that is similar to the pituitary hormones released in humans pituitary glands. The metamorphosis of insects is quite similar to the transition of humans on the onset of puberty. When the insect reach the threshold body weight, a signal was sent to the brain releasing the PTTH and received by a receptor molecule located in the main endocrine organ in the insect and initiating metamorphosis. The researchers found out that the receptor is an enzyme that serves as the switch in turning on other enzymes that yield to the different changes that occur during metamorphosis (Morrison, 2009).
   
Amphibians
The duration of metamorphosis is measured from the time of hatching until the transition from the aquatic to terrestrial habitat. The metamorphosis of amphibians is influenced by both biotic and abiotic factors. In most cases, metamorphosis is influenced by hypothalamic-pituitary axis. The larva of most amphibians like frogs, the rapid and accelerated development is a response to desiccation and other stress-related environmental factors. The response is involved with corticosteroidstimulationof thyroid stimulating hormone, which results inTH synthesis and accelerated restructuring of the tadpole towardmetamorphic climax. (Heyland  Moroz, 2006, p.747).
   
In all organisms undergoing metamorphosis, environmental cues play an important part in the biological process. Many insects often enter the dormant or the inactive state of development during winter. The low temperature triggers metamorphosis in most insects. The length of light and darkness or the solstices trigger the metamorphosis of some organisms. These environmental factors send message to the brain and signal the onset of metamorphosis.

Indirect Development of Bull Frogs
The eggs are fertilized externally as they are laid in the water. The little larva which hatches in a few days has two pairs of long, branched, external gills projecting from the dorsal ends of the third and fourth visceral arches. It is really inactive and clinging to vegetation in the aquatic environment through the glandular adhesive organ under lower jaw. Once the reserve yolk has been used up, however, the larva swims more actively and the adhesive organ disappears. The bases of the external gills are gradually covered by the growth of opercular folds and the so-called internal gills growing from the lower ends of the visceral arches that take over the respiratory function. Horny teeth and jaw coverings appear around the mouth that comprised a typical tadpole that is capable of swimming and breathing in water and for rasping away the surface of the vegetation that is his food source (Lynn, 1961).
   
The metamorphic changes occur and the most obvious changes are seen in the physical and external changes. There is a rapid growth and development of hind legs. There is a loss in the horny teeth and a change in the structure in the head and mouth, including the protrusion of eyes and sudden appearance of fore limbs within the opercular cavity. The tail and other useless body tissue undergo resorption. The gills used for breathing and the spiral gut used for digesting are lost (Lynn, 1961).
   
The changes during metamorphosis are brought about by the secretion of thyroxine (T4) and triiodothyronine (T3) from the thyroid gland. The environmental cues send signal to the thyroid gland that excretes hormones responsible for the inception of the metamorphosis. Thyroid hormones activate the transcription of some genes while at the same thing repressed other genes. At the onset of metamorphosis, the levels of thyrothropin increase that is probably due to the developmental maturation of the pituitary gland. Due to this maturation, there is an increase in the amount of T3. The T3 binds with the receptor mRNA. The other T-induced proteins are also needed for the transcription of more T3 message.
   
Both the larval and adult developmental programare under the control of various endogenous factors, 2 essentialones being the levels of thyroid hormone receptors (TRs) andthe concentration of intracellular free thyroid hormone (TH).Triiodo-L-tyrosine (T3) is the active hormone in amphibian metamorphosisthat binds with very high affinity to TRs. The action of THin metamorphosis can be best described by the so-called dual-functionmodel. Based on this model, TR without its ligand functions as a repressor of TH-regulatedgenes, while the conformational changes that occur upon ligandbinding change TR into an activator of TH-regulated genes. Sucha mechanism fulfills the very important function of repressingthe metamorphic genes by TR until the larva is ready to undergothe metamorphic transition in both a developmental and ecologicalsense (Heyland  Moroz, 2006, p.746).
   
Metamorphosis is an important biological process in some organisms in order to achieve their adult form. Bullfrogs are examples of an organism that undergoes metamorphosis. The genetic control of the gene expression of an organism plays an important role in the onset of metamorphosis. Metamorphosis causes significant adaptive changes in the organism causing the m to adapt on the different facets of the environment. The metamorphosis of an organism is triggered by environmental cues that send signals to the biological aspects of the body that is responsible for the process of metamorphosis. Metamorphosis is an important process in some organisms and their adaptation in the inherent environment.

Oxygen is a basic requirement for the survival of mankind. This is because it aids in the bodys respiration process. On the other side, although plants respire just like we do, they do so only for few hours in a day. Plants make their own through a process called photosynthesis. This process requires water, nutrients from the soil, sunlight and carbon dioxide. This paper is written to support the fact that there could be no people without plants.

According to scientific evidence, plants mostly breathe in carbon dioxide through tiny hole in their leaves referred to as stomata (Jowsey, 2007). Still, plants have chlorophyll which acts to capture energy from the sunlight which is used in the process of making food in a process called photosynthesis (Khara, 2009). It is to be noted here that plant food is made by combining water and carbon dioxide with sunlight energy as a catalyst to produce sugar, starch and oxygen. This oxygen is released through the leaves into the air. On the other side, human beings take in this oxygen for respiration, a process which leads to the breakdown of sugar into energy, water and carbon dioxide. It is this carbon dioxide which we breathe out. This is the reason why human beings and plants are mutually dependent on each other (Manning, 2008).

However, it is worth noting that all living things including plants need oxygen for respiration. Although plant use carbon dioxide to makes the food we eat, they still need part of this food for growth andor remain healthy. This process is called respiration and requires the intake of oxygen. During the process of respiration, plants breathe out carbon dioxide, which is a by product of starch and oxygen (Khara, 2009). Just to be stated here is the fact that this process usually takes place during the night. It is due to this reason that the author claims that a plant in an air tight box without an oxygen source cannot survive.

The functioning of the human body mainly relies on the amount of food stored in the body and the bodys ability to break it down into energy, water and carbon dioxide. Therefore, human bodies do not make their own food. Plants are however capable of making their own food in the presence of sunlight energy thus giving out oxygen (Jowsey, 2007). However, during the night plant have to use energy for respiration. Therefore, means that people, unlike plants cannot survive alone. This is because they are not capable of naturally converting carbon dioxide to oxygen and verse versa.

The premature stoppage of the biosphere experiment of 1980s can be best explained based on the above reasoning. The aim of the project was to test sustainable living of a man. This meant living in a sealed space and planting trees for food and air purification. It is however to be stated that with increased plant, more carbon dioxide could be required for photosynthesis (Jowsey, 2007). Still, more oxygen was required by the plants to respire at night thus making it impossible for human beings to survive.

In conclusion, it is quite clear that without plants, people cannot survive. This is because plants act to purify air for people to use. Plants breakdown carbon dioxide to give oxygen in a process called photosynthesis. However, plant still need oxygen for respiration especially during. This competition for oxygen between plant and human beings is what led to the premature stopping of the biosphere experiment.

Though considered to be microscopic, cells reproduce themselves in an elaborate cycle called the cell cycle (Morgan, 2007, p.1). Some processes involved in the cell division cycle are mitosis and meiosis which are often confused with each other.
   
Mitosis or nuclear division is the complex process by which the eukaryotic cell divides the chromosomes in its nucleus equally into two identical daughter nuclei (Morgan, 2007, p.4). Mitosis is also one of the major processes involved in the second major phase of the cell cycle called the mitotic phase.  . The stages in mitosis are interphase, prophase, metaphase, anaphase and telophase (Hollingsworth, et. al., 2008, p.158).
   
Meiosis on the other hand is a specialized form of cell division for it produces four genetically distinct haploid cells (Norman, et. al., 2007, p.104). Haploid cells are those which contain only a single copy of each chromosome. This reductive cell division is found only in gamete production or oogenesis and spermatogenesis. Meiosis also requires two rounds of cell division the first round which produces genetic variation and the second round which generates the aforementioned haploid cells.
   
The main difference of mitosis and meiosis is that in mitosis, there is only a single division which produces two daughter cells while in meiosis there are two successive divisions which yield a total of four cells (Berg, 2007, p. 250).  Also, in mitosis the daughter cells contain identical sets of chromosomes while in meiosis, one chromosome of each pair is distributed randomly in daughter cells. Most importantly, mitosis can happen to all the cells in the body unlike meiosis which happens only in gamete production.
   
Both cycles are important in growth and development of a living organism. Despite often being confused with each other, both processes are important in the cell cycle of an organism.