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Nurs 210 Module 6 Study
Guide
Health Assessment (Liberty University)
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Study Guide Module 6
Diseases
-xeroderma pigmentosum; which is commonly known as XP, is an inherited
condition characterized by an extreme sensitivity to ultraviolet (UV) rays from
sunlight. This condition mostly affects the eyes and areas of skin exposed to the sun.
Some affected individuals also have problems involving the nervous system.The signs
of xeroderma pigmentosum usually appear in infancy or early childhood. Many
affected children develop a severe sunburn after spending just a few minutes in the sun
-osteogenesis imperfecta; is a genetic disorder characterized by bones that break easily,
often from little or no apparent cause. A classification system of different types of OI is
commonly used to help describe how severely a person with OI is affected. For
example, a person may have just a few or as many as several hundred fractures in a
lifetime.
Prevalence
While the number of people affected with OI in the United States is unknown, the best estimate
suggests a minimum of 20,000 and possibly as many as 50,000.
Diagnosis
OI is caused by genetic defects that affect the body’s ability to make strong bones. In dominant
(classical) OI, a person has too little type I collagen or a poor quality of type I collagen due to a
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mutation in one of the type I collagen genes. Collagen is the major protein of the body’s
connective tissue. It is part of the framework that bones are formed around. In recessive OI,
mutations in other genes interfere with collagen production. The result in all cases is fragile
bones that break easily. It is often, though not always, possible to diagnose OI based solely on
clinical features. Clinical geneticists can also perform biochemical (collagen) or molecular
(DNA) tests that can help confirm a diagnosis of OI in some situations. These tests generally
require several weeks before results are known. Both the collagen biopsy test and DNA test
are thought to detect almost 90% of all type I collagen mutations.
A positive type I collagen study confirms the diagnosis of dominant OI, but a negative result
could mean that either a collagen type I mutation is present but was not detected or the patient
has a form of the disorder that is not associated with type 1 collagen mutations or the patient has
a recessive form of OI. Therefore, a negative type I collagen study does not rule out OI. When a
type I collagen mutation is not found, other DNA tests to check for recessive forms are
available.
-sickle cell disease; The term sickle cell disease (SCD) describes a group of inherited red
blood cell disorders. People with SCD have abnormal hemoglobin, called hemoglobin S
or sickle hemoglobin, in their red blood cells.
Hemoglobin is a protein in red blood cells that carries oxygen throughout the body.
<Inherited= means that the disease is passed by genes from parents to their children. SCD is
not contagious. A person cannot catch it, like a cold or infection, from someone else.
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People who have SCD inherit two abnormal hemoglobin genes, one from each parent. In all
forms of SCD, at least one of the two abnormal genes causes a person’s body to make
hemoglobin S. When a person has two hemoglobin S genes, Hemoglobin SS, the disease is
called sickle cell anemia. This is the most common and often most severe kind of SCD.
Hemoglobin SC disease and hemoglobin Sβ thalassemia (thal-uh-SEE-me-uh) are two other
common forms of SCD
-beta thalassemia; is a blood disorder that reduces the production of hemoglobin.
Hemoglobin is the iron-containing protein in red blood cells that carries oxygen to cells
throughout the body. In people with beta thalassemia, low levels of hemoglobin lead to
a lack of oxygen in many parts of the body.
- Affected individuals also have a shortage of red blood cells (anemia), which can
cause pale skin, weakness, fatigue, and more serious complications. People with beta
thalassemia are at an increased risk of developing abnormal blood clots.
- Beta thalassemia is classified into two types depending on the severity of symptoms:
thalassemia major (also known as Cooley's anemia) and thalassemia intermedia. Of the
two types, thalassemia major is more severe.
-achondroplasia; Achondroplasia is a form of short-limbed dwarfism. The word
achondroplasia literally means "without cartilage formation." Cartilage is a tough but
flexible tissue that makes up much of the skeleton during early development. However,
in
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achondroplasia the problem is not in forming cartilage but in converting it to bone (a
process called ossification), particularly in the long bones of the arms and legs.
Achondroplasia is similar to another skeletal disorder called hypochondroplasia, but the
features of achondroplasia tend to be more severe.
- All people with achondroplasia have short stature. The average height of an adult male
with achondroplasia is 131 centimeters (4 feet, 4 inches), and the average height for adult
females is 124 centimeters (4 feet, 1 inch). Characteristic features of achondroplasia
include an average-size trunk, short arms and legs with particularly short upper arms and
thighs, limited range of motion at the elbows, and an enlarged head (macrocephaly) with
a prominent forehead. Fingers are typically short and the ring finger and middle finger
may diverge, giving the hand a three-pronged (trident) appearance. People with
achondroplasia are generally of normal intelligence.
- Health problems commonly associated with achondroplasia include episodes in which
breathing slows or stops for short periods (apnea), obesity, and recurrent ear infections.
In childhood, individuals with the condition usually develop a pronounced and
permanent sway of the lower back (lordosis) and bowed legs. Some affected people also
develop abnormal front-to-back curvature of the spine (kyphosis) and back pain.
-skin cancer; Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs
when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation
from sunshine or tanning beds) triggers mutations, or genetic defects, that lead the skin
cells to multiply rapidly and form malignant tumors.
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Mutation; A mutation is a change that occurs in our DNA sequence, either due to mistakes
when the DNA is copied or as the result of environmental factors such as UV light and cigarette
smoke. Over a lifetime our DNA? can undergo changes or mutations? ’ in the sequence of bases?
, A, C, G and T.
This result in changes in the proteins? that are made. This can be a bad or a good thing.
Mutations can occur during DNA replication, if errors are made and not corrected in time.
Mutations can also occur as the result of exposure to environmental factors such as smoking,
sunlight and radiation.
Often cells can recognise any potentially mutation-causing damage and repair it before it
becomes a fixed mutation.
Mutations contribute to genetic variation? within species? .
Mutations can also be inherited, particularly if they have a positive effect. For example, the
disorder sickle cell anemia is caused by a mutation in the gene? that instructs the building of a
protein called hemoglobin . This cause red blood cells? to become an abnormal, rigid, sickle
shape. However, in African populations, having this mutation also protects against malaria?
However, mutation can also disrupt normal gene activity and cause diseases, like cancer?
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Cancer is the most common human genetic disease; it is caused by mutations occurring in a
number of growth-controlling genes. Sometimes faulty, cancer-causing genes can exist
from birth, increasing a person’s chance of getting cancer.
-beneficial; DNA is constantly subject to mutations, accidental changes in its code.
Mutations can lead to missing or malformed proteins, and that can lead to disease.
We all start out our lives with some mutations. These mutations inherited from your parents are
called germ-line mutations. However, you can also acquire mutations during your lifetime.
Some mutations happen during cell division, when DNA gets duplicated. Still other mutations
are caused when DNA gets damaged by environmental factors, including UV radiation,
chemicals, and viruses.
Few mutations are bad for you. In fact, some mutations can be beneficial. Over time, genetic
mutations create genetic diversity, which keeps populations healthy. Many mutations have
no effect at all. These are called silent mutations.
-
deleterious; A deleterious gene is one that virtually all reasonable individuals <would
judge consistently to cause very premature death or serious health problems that
drastically compromise the capacity= of afflicted individuals to carry out normal or
near-normal life plans. So wrote medical ethicist and philosopher Leonard M. Fleck in his
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essay, "Just Genetics: A Problem Agenda," which appeared in the collection "Justice and
the Human Genome Project."
- Examples of deleterious genes include those for Huntington’s disease, cystic fibrosis,
Tay-Sachs disease, sickle-cell anemia and a predisposition toward coronary artery
dise
-thymine dimer; are produced when adjacent thymine residues are covalently linked by
exposure to ultraviolet radiation. Covalent linkage may result in the dimer being
replicated as a single base, which results in a frameshift mutation.
are molecular lesions formed from thymine or cytosine bases in DNA via photochemical
reactions.
[1]
[2]
Ultraviolet light induces the formation of covalent linkages by reactions localized
on the C=C double bonds.[3] In dsRNA (double-stranded RNA), uracil dimers may also
accumulate as a result of UV radiation. Two common UV products are cyclobutane pyrimidine
dimers (CPDs, including thymine dimers) and 6,4 photoproducts. These premutagenic lesions
alter the structure of DNA and consequently inhibit polymerases and arrest replication. Dimers
may be repaired by photoreactivation or nucleotide excision repair, but unrepaired dimers are
mutagenic. Pyrimidine dimers are the primary cause of melanomas in humans
-recessive; A recessive gene is a gene that can be masked by a dominant gene. In order to
have a trait that is expressed by a recessive gene, such as blue eyes, you must get the gene
for blue eyes from both of your parents.
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You might remember the word recessive from biology, where it most often appears. Its opposite
is dominant and is always living in its shadow. A recessive allele has to team up with another
recessive allele in order to show up. We can also use recessive to describe something that has
the tendency to withdraw or recede, or something pertaining to an economic recession.
-germline mutation; A germline mutation is any detectable and heritable variation in the
lineage of germ cells. Mutations in these cells are transmitted to offspring, while, on the
other hand, those in somatic cells are not -mutation rate; Recently reported estimates of
the human genome-wide mutation rate. The human germline mutation rate is
approximately 0.5×10−9 per base pair per year. In genetics, the mutation rate is a
measure of the rate at which various types of mutations occur over time
-deletion mutation; In genetics, a deletion (also called gene deletion, deficiency, or
deletion mutation) (sign: Δ) is a mutation (a genetic aberration) in which a part of a
chromosome or a sequence of DNA is lost during DNA replication. Any number
of nucleotides can be deleted, from a single base to an entire piece of chromosome.
-splice site; A splice site mutation is a genetic mutation that inserts, deletes or changes a
number of nucleotides in the specific site at which splicing takes place during the
processing of precursor messenger RNA into mature messenger RNA.
Mechanism Of Darwinian Evolution;
1. Because of the "Struggle for Existence", few offspring survive to reproduce
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2. Any heritable variation that improves an individual's ability to survive and reproduce
(i.e., its "Fitness") will tend to be passed on to the next generation: "Natural Selection"
These theses will be explored in the following pages in a way that combines Darwin's intuitive
feeling for population dynamics with a mathematical foundation.
Mutation, a driving force of evolution, is a random change in an organism’s genetic
makeup, which influences the population’s gene pool. It is a change in the nature of the DNA
in one or more chromosomes. Mutations give rise to new alleles; therefore, they are a source
of genetic variation in a population.
Mutations may be harmful or benign, but they may also be beneficial. For example, a mutation
may permit organisms in a population to produce enzymes that will allow them to use certain
food materials. Over time, these types of individuals survive, while those that don’t have the
mutations are more likely to perish. Therefore, natural selection tends to remove the less-fit
individuals, allowing more-fit individuals to survive and form a population.
Natural selection
Another mechanism for evolution is natural selection, which occurs when populations of
organisms are subjected to the environment. The fittest creatures are more likely to survive
and pass their genes to their offspring, producing a population that is better adapted to the
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environment. The genes of less-fit individuals are less likely to be passed on to the next
generation. The important selective force in natural selection is the environment.
Environmental fitness may be expressed in several ways. For example, it may involve an
individual’s ability to avoid predators, it may imply a greater resistance to disease, it may
enhance ability to obtain food, or it may mean resistance to drought. Fitness may also be
measured as enhanced reproductive ability, such as the ability to attract a mate. Better-
adapted individuals produce relatively more offspring and pass on their genes more
successfully than less-adapted individuals.
Several types of natural selection appear to affect populations. One type, stabilizing selection,
occurs when the environment selects against organisms of a population with extreme versions of
a trait. Another type of natural selection is disruptive selection. Here, the environment favors
extreme types in a population at the expense of intermediate forms, thereby splitting the
population into two or more subpopulations. A third type of natural selection is directional
selection. In this case, the environment selects for an extreme characteristic. The development
of antibiotic-resistant bacteria in the modern era is an example of directional selection.
Beneficial Mutations
-CCR5 gene; is a protein on the surface of white blood cells that is involved in the
immune system as it acts as a receptor for chemokines.
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●This is the process by which T cells are attracted to specific tissue and
organ targets.
●Many forms of HIV, the virus that causes AIDS, initially use CCR5 to enter
and infect host cells.
●Certain individuals carry a mutation known as CCR5-Δ32 in the CCR5 gene,
protecting them against these strains of HIV.
●In humans, the CCR5 gene that encodes the CCR5 protein is located on the short
(p) arm at position 21 on chromosome 3.
●Certain populations have inherited the Delta 32 mutation resulting in the genetic
deletion of a portion of the CCR5 gene.
●Homozygous carriers of this mutation are resistant to M-tropic strains of HIV-
1 infection
-somatic hypermutation; (or SHM) is a cellular mechanism by which the immune
system adapts to the new foreign elements that confront it (e.g. microbes), as seen during
class switching.
●A major component of the process of affinity maturation, SHM diversifies B
cell receptors used to recognize foreign elements (antigens) and allows the
immune system to adapt its response to new threats during the lifetime of an
organism.[1]
●Somatic hypermutation involves a programmed process of mutation affecting
the variable regions of immunoglobulin genes.
●Unlike germline mutation, SHM affects only an organism's individual immune
cells, and the mutations are not normally transmitted to the organism's
offspring[2]
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except in those circumstances associated with the antigen-driven somatic and
germline evolution of germline V segment arrays, so called soma-to-
germline feedback or Lamarckian inheritance effects.[3][4][5][6]
●Mistargeted somatic hypermutation is a likely mechanism in the development
of B-cell lymphomas [7] and many other cancers.
Genetic
Mechanisms And Terminology
-triplet code; the normal version of the genetic code in which a sequence of three
nucleotides codes for the synthesis of a specific amino acid genetic code
●the ordering of nucleotides in DNA molecules that carries the genetic
information in living cells
-translation; In molecular biology and genetics, translation is the process in which
ribosomes in a cell's cytoplasm create proteins, following transcription of DNA to RNA
in the cell's nucleus. The entire process is a part of gene expression.
-DNA repair mechanisms; In order to repair damage to one of the two paired
molecules of DNA, there exist a number of excision repair mechanisms that remove the
damaged nucleotide and replace it with an undamaged nucleotide complementary to
that found in the undamaged DNA strand.
Cancer Concepts Terminology
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-p53; also known as TP53 or tumor protein (EC :2.7.1.37) is a gene that codes for a
protein that regulates the cell cycle and hence functions as a tumor suppression. It is very
important for cells in multicellular organisms to suppress cancer. P53 has been described
as "the guardian of the genome", referring to its role in conserving stability by preventing
genome mutation (Strachan and Read, 1999). The name is due to its molecular mass: it is
in the 53 kilodalton fraction of cell proteins.
p53 was identified in 1979 by Arnold Levine,David Lane and William Old,working at Princeton
University, Dundee University (UK) and Sloan-Kettering Memorial Hospital, respectively. It
had been hypothesized to exist before as the target of the SV40 virus, a strain that induced
development of tumors.Although it was initially presumed to be an oncogene, its character as a
tumor suppressor gene was revealed in 1989.In 1993, p53 protein has been voted molecule of the
year by the Science magazine. The human p53 gene is located on the seventeenth chromosome.
●The p53 protein is a phosphoprotein made of 393 amino acids.
- It consists of four units (or domains):
●A domain that activates transcription factors.
●A domain that recognizes specific DNA sequences (core domain).
●A domain that is responsible for the tetramerization of the protein.
A domain that recognized damaged DNA, such as misaligned base pairs or single-stranded
DNA.
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Wild-type p53 is a labile protein, comprising folded and unstructured regions which function in a
synergistic manner (Bell et al. 2002).p53 protein has been voted molecule of the year.
-Gleevec; Gleevec (imatinib) interferes with the growth of some cancer cells.
●Gleevec is used to treat certain types of leukemia (blood cancer), bone marrow
disorders, and skin cancer, or certain tumors of the stomach and digestive
system.
●Gleevec may also be used for purposes not listed in this medication guide.
●Gleevec can lower blood cells that help your body fight infections and help your
blood to clot.
- You may get an infection or bleed more easily.
- Call your doctor if you have unusual bruising or bleeding, or signs of
infection (fever, chills, body aches).
Leukemia Symptoms And Lessons: Is A Solution In Sight?
Gleevec may increase the risk of liver problems. Tell your doctor if you have upper stomach
pain, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).
Gleevec may increase the risk of fluid retention or heart problems. Tell your doctor if you have
swelling or rapid weight gain, shortness of breath, fast or slow heart rate, weak pulse, or fainting.
-HER2; also known as CD340 (cluster of differentiation 340), proto-oncogene Neu,
Erbb2 (rodent), or ERBB2 (human). It is a protein that in humans is encoded by the
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ERBB2 gene, and it is also frequently called HER2 (from human epidermal growth factor
receptor 2) or HER2/neu.
[4][5][6]
HER2 is a member of the human epidermal growth factor
receptor (HER/EGFR/ERBB) family. Amplification or over-expression of this oncogene
has been shown to play an important role in the development and progression of certain
aggressive types of breast cancer. In recent years the protein has become an important
biomarker and target of therapy for approximately 30% of breast cancer patients.[7]
-oncogenes; An oncogene is a gene that has the potential to cause cancer. [1] In
tumor cells, they are often mutated or expressed at high levels.[2]
Most normal cells will undergo a programmed form of rapid cell death (apoptosis) when
critical functions are altered. Activated oncogenes can cause those cells designated for
apoptosis to survive and proliferate instead.[3] Most oncogenes require an additional step,
such as mutations in another gene, or environmental factors, such as viral infection, to
cause cancer. Since the 1970s, dozens of oncogenes have been identified in human
cancer. Many cancer drugs target the proteins encoded by oncogenes.
-tumor suppressor gene; A tumor suppressor gene, or antioncogene, is a gene that
protects a cell from one step on the path to cancer. When this gene mutates to cause a
loss or reduction in its function, the cell can progress to cancer, usually in combination
with other genetic changes.
-cell cycle checkpoint; Internal Checkpoints During the Cell Cycle. The cell cycle is
controlled at three checkpoints. The integrity of the DNA is assessed at the G1
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checkpoint. Proper chromosome duplication is assessed at the G2 checkpoint. Attachment
of each kinetochore to a spindle fiber is assessed at the Mcheckpoint.
- HELA cells;
A HeLa cell / hi l / ˈ ː ɑː , also Hela or hela cell, is a cell type in an immortal cell line used in
scientific research. It is the oldest and most commonly used human cell line.[1] The line was
derived from cervical cancer cells taken on February 8, 1951[2] from Henrietta Lacks, a patient
who died of her cancer on October 4, 1951. The cell line was found to be remarkably durable and
prolific which warrants its extensive use in scientific research.[3][4]
The cells from Lacks's cancerous cervical tumor were taken without her knowledge or consent
by researcher George Gey, who found that they could be kept alive.[5] Before this, cells cultured
from other human cells would only survive for a few days. Scientists spent more time trying to
keep the cells alive than performing actual research on them. Cells from Lacks's tumor behaved
differently. George Gey was able to isolate one specific cell, multiply it, and develop what is
called a 'cell line'. As was custom for Gey's lab assistant, she labeled the culture 'HeLa', the first
two letters of the patient's first and last name; this became the name of the cell line.
These were the first human cells grown in a lab that were naturally "immortal", meaning that
they do not die after a set number of cell divisions (i.e. lack of senescence). These cells could
be used for conducting a multitude of medical experiments- if the cells died, they could simply
be thrown away and the experiment could be repeated on new cells without the potential loss of
human life. This represented an enormous boon to medical and biological research
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dedifferentiation;
- Dedifferentiation, or integration is a cellular process often seen in more basal life
forms such as worms and amphibians in which a partially or terminally differentiated
cell reverts to an earlier developmental stage, usually as part of a regenerative process.
-Angiogenesis is the formation of new blood vessels. This process involves the migration,
growth, and differentiation of endothelial cells, which line the inside wall of blood
vessels. The process of angiogenesis is controlled by chemical signals in the body.
-adoptive immunotherapy; T cells are collected from a patient and grown in the
laboratory. This increases the number of T cells that are able to kill cancer cells or
fight infections. These T cells are given back to the patient to help the immune system
fight disease. Also called cellular adoptive immunotherapy.
-DNA repair mechanisms; is a collection of processes by which a cell identifies and
corrects damage to the DNA molecules that encode its genome. In human cells, both
normal metabolic activities and environmental factors such as radiation can cause DNA
damage, resulting in as many as 1 million individual molecular lesions per cell per day.
[1] Many of these lesions cause structural damage to the DNA molecule and can alter or
eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other
lesions induce potentially harmful mutations in the cell's genome, which affect the
survival of its daughter cells after it undergoes mitosis. As a consequence, the DNA
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repair process is constantly active as it responds to damage in the DNA structure.
When normal repair processes fail, and when cellular apoptosis does not occur,
irreparable DNA damage may occur, including double-strand breaks and DNA cross
linkages (interstrand crosslinks or ICLs).[2][3] This can eventually lead to malignant
tumors, or cancer as per the two hit hypothesis.
Cancer Concepts Terminology
-metastasis; The main reason that cancer is so serious is its ability to spread in the body.
Cancer cells can spread locally by moving into nearby normal tissue. Cancer can also
spread regionally, to nearby lymph nodes, tissues, or organs. And it can spread to
distant parts of the body. When this happens, it is called metastatic cancer. For many
types of cancer, it is also called stage IV (four) cancer. The process by which cancer
cells spread to other parts of the body is called metastasis.
When observed under a microscope and tested in other ways, metastatic cancer cells have
features like that of the primary cancer and not like the cells in the place where the cancer is
found. This is how doctors can tell that it is cancer that has spread from another part of the
body.
Metastatic cancer has the same name as primary cancer. For example, breast cancer that spreads
to the lung is called metastatic breast cancer, not lung cancer. It is treated as stage IV breast
cancer, not as lung cancer.
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Sometimes when people are diagnosed with metastatic cancer, doctors cannot tell where it
started. This type of cancer is called cancer of unknown primary origin, or CUP. See the
Carcinoma of Unknown Primary page for more information.
