TurkeyOnRye
Well-Known Member
I'm writing a Biology term paper on Cystic Fibrosis. It's still a rough draft, but I'm nearly finished and was hoping to get some feedback from people on grammar, formatting and accuracy of claims. By all means, tear it up! Any feedback would be much appreciated. :yes:
An Overview of Cystic Fibrosis:
Genetics, Symptoms, Diagnosis, & Treatment
Cystic fibrosis (CF) is a relatively rare yet life-threatening disease (Cystic Fibrosis Foundation-1, 2012). It affects approximately seventy thousand people world-wide including thirty thousand Americans (Cystic Fibrosis Foundation-1, 2012). Frequency of CF is highest among caucasians with an incidence of approximately 1 in 1000-4000 births depending on region (Shastri et al., 2008; Southern et al., 2007). Early recognition and treatment is vital to promoting a long and healthy life-span. Left untreated, CF is lethal and affected individuals die in early adolescence, however, modern treatment options are extending life-expectancy and improving quality of life for those affected (Cystic Fibrosis Foundation-1, 2012). To understand CF, we must consider several factors related to the disease including its genetic attributes, typical symptoms, the process of diagnosis and available treatment options.
CF is caused by a mutated autosomal recessive allele (Griesenbach and Boyd, 2005) that corresponds to the cystic fibrosis transmembrane conductance regulator (CFTR) gene located on chromosome seven (Shastri et al., 2008). Over seventeen hundred unique CFTR allele mutations are recognized (Lay-Son et al., 2011). Among them, Delta-F508 is the most common mutation (about 66% occurrence in CF individuals) and is characterized by a deletion of the codon used to create phenylalanine located at position 508 on the chromosome (Sinaasappel et al., 2002). The CFTR gene codes for the production of a protein channel required to regulate chloride ion concentration between the plasma membranes of associated cells (Griesenbach and Boyd, 2005). This protein is commonly expressed in the epithelial cells that line the airways of lungs and various passages of the pancreas, liver, intestines, reproductive organs and skin (Starr et al., 2009). Faulty CFTR alleles are responsible for creating defective variations of this protein or terminating its production and as a result, CF symptoms occur (Laurie and Fundukian, 2011).
The most universally characteristic and life-threatening symptom of CF is lung airway obstruction caused by progressive buildup of dehydrated mucus (Bilton and Hurt, 2012). In a healthy lung, chloride transport proteins move chloride ions out of an epithelial cell which creates a concentration gradient across the plasma membrane that water molecules follow via osmosis (Zemanick et al., 2010). As water molecules exit the cell, a thin fluid layer forms which supports cellular immunity and functions as an epithelial lubricant (Bilton and Hurt, 2012). In cystic fibrosis-afflicted lungs, the chloride transport proteins are rendered ineffective and as a result, chloride ions stagnate inside the cell failing to produce the concentration gradient necessary for water movement (Zemanick et al., 2010). Dry sticky mucus then persists on the surface of epithelial cells; this obstruction and irritation inevitably results in inflammation and bacterial infections of the lung tissue (Konstan et al., 2011). Pseudomonas aeruginosa, among others, is a bacterium commonly associated with these infections and is a primary contributor to the progressive decline in lung function (Ren et al., 2008).
CF is an inherited autosomal recessive trait which means that it is passed down by both parents and is not dependent on sex for its expression (Starr et al., 2009). Individuals that have inherited only one copy of the allele do not express the trait, but are carriers for it (Starr et al., 2009). This means that affected individuals possess a homozygous genotype while carriers-only have a heterozygous genotype (Starr et al., 2009). Heterozygous parents therefore present to each of their children a 25% chance of expressing the trait, a 50% chance of being carriers for it, and a 25% chance that they will neither express the trait nor be carriers for it (Starr et al., 2009).
CF can be difficult for both patients and loved ones due to the immense amount of suffering it causes. An important aspect of reducing such suffering is early diagnosis (Sims et al., 2005). Today, the United States has newborn screening (NBS) programs operating in all fifty states designed to detect CF (among many other common health abnormalities) through a variety of methods (Groose et al., 2010). NBS involves acquiring blood samples from newborn infants within the first few days following birth (Cystic Fibrosis Foundation-2, 2012). Infants who test positive for CF during a screening undergo more thorough testing to verify results, most commonly in the form of a sweat test (Southern et al., 2007).
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An Overview of Cystic Fibrosis:
Genetics, Symptoms, Diagnosis, & Treatment
Cystic fibrosis (CF) is a relatively rare yet life-threatening disease (Cystic Fibrosis Foundation-1, 2012). It affects approximately seventy thousand people world-wide including thirty thousand Americans (Cystic Fibrosis Foundation-1, 2012). Frequency of CF is highest among caucasians with an incidence of approximately 1 in 1000-4000 births depending on region (Shastri et al., 2008; Southern et al., 2007). Early recognition and treatment is vital to promoting a long and healthy life-span. Left untreated, CF is lethal and affected individuals die in early adolescence, however, modern treatment options are extending life-expectancy and improving quality of life for those affected (Cystic Fibrosis Foundation-1, 2012). To understand CF, we must consider several factors related to the disease including its genetic attributes, typical symptoms, the process of diagnosis and available treatment options.
CF is caused by a mutated autosomal recessive allele (Griesenbach and Boyd, 2005) that corresponds to the cystic fibrosis transmembrane conductance regulator (CFTR) gene located on chromosome seven (Shastri et al., 2008). Over seventeen hundred unique CFTR allele mutations are recognized (Lay-Son et al., 2011). Among them, Delta-F508 is the most common mutation (about 66% occurrence in CF individuals) and is characterized by a deletion of the codon used to create phenylalanine located at position 508 on the chromosome (Sinaasappel et al., 2002). The CFTR gene codes for the production of a protein channel required to regulate chloride ion concentration between the plasma membranes of associated cells (Griesenbach and Boyd, 2005). This protein is commonly expressed in the epithelial cells that line the airways of lungs and various passages of the pancreas, liver, intestines, reproductive organs and skin (Starr et al., 2009). Faulty CFTR alleles are responsible for creating defective variations of this protein or terminating its production and as a result, CF symptoms occur (Laurie and Fundukian, 2011).
The most universally characteristic and life-threatening symptom of CF is lung airway obstruction caused by progressive buildup of dehydrated mucus (Bilton and Hurt, 2012). In a healthy lung, chloride transport proteins move chloride ions out of an epithelial cell which creates a concentration gradient across the plasma membrane that water molecules follow via osmosis (Zemanick et al., 2010). As water molecules exit the cell, a thin fluid layer forms which supports cellular immunity and functions as an epithelial lubricant (Bilton and Hurt, 2012). In cystic fibrosis-afflicted lungs, the chloride transport proteins are rendered ineffective and as a result, chloride ions stagnate inside the cell failing to produce the concentration gradient necessary for water movement (Zemanick et al., 2010). Dry sticky mucus then persists on the surface of epithelial cells; this obstruction and irritation inevitably results in inflammation and bacterial infections of the lung tissue (Konstan et al., 2011). Pseudomonas aeruginosa, among others, is a bacterium commonly associated with these infections and is a primary contributor to the progressive decline in lung function (Ren et al., 2008).
CF is an inherited autosomal recessive trait which means that it is passed down by both parents and is not dependent on sex for its expression (Starr et al., 2009). Individuals that have inherited only one copy of the allele do not express the trait, but are carriers for it (Starr et al., 2009). This means that affected individuals possess a homozygous genotype while carriers-only have a heterozygous genotype (Starr et al., 2009). Heterozygous parents therefore present to each of their children a 25% chance of expressing the trait, a 50% chance of being carriers for it, and a 25% chance that they will neither express the trait nor be carriers for it (Starr et al., 2009).
CF can be difficult for both patients and loved ones due to the immense amount of suffering it causes. An important aspect of reducing such suffering is early diagnosis (Sims et al., 2005). Today, the United States has newborn screening (NBS) programs operating in all fifty states designed to detect CF (among many other common health abnormalities) through a variety of methods (Groose et al., 2010). NBS involves acquiring blood samples from newborn infants within the first few days following birth (Cystic Fibrosis Foundation-2, 2012). Infants who test positive for CF during a screening undergo more thorough testing to verify results, most commonly in the form of a sweat test (Southern et al., 2007).
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