Area 3 – Social/Behavioral/Administrative Sciences (22%)

3F Biostatistics and Research Design

Types of Clinical study designs

The following list describes each type of clinical study design and cites an example.

1. Meta-Analysis- A way of combining data from many different research studies. A meta-analysis is a statistical process that combines the findings from individual studies.

Example: Anxiety outcomes after physical activity interventions: meta-analysis finding.

          Types of clinical Study designs

2. Systematic Review-A summary of the clinical literature. A systematic review is a critical assessment and evaluation of all research studies that address a particular clinical issue. The researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a set of specific criteria. A systematic review typically includes a description of the findings of the collection of research studies. The systematic review may also include a quantitative pooling of data, called a meta-analysis.

Example:Complementary and alternative medicine use among women with breast cancer: a systematic review.

3.Randomized Controlled Trial -A controlled clinical trial that randomly (by chance) assigns participants to two or more groups. There are various methods to randomize study participants to their groups.

Example:Meditation or exercise for preventing acute respiratory infection: a randomized controlled trial.

4. Cohort Study (Prospective Observational Study) -A clinical research study in which people who presently have a certain condition or receive a particular treatment are followed over time and compared with another group of people who are not affected by the condition.

Example: Smokeless tobacco cessation in South Asian communities: a multi-centre prospective cohort study

5. Comparative Study- Comparison of outcomes, results, responses, etc. for different techniques, therapeutic approaches or other inputs.

Example: Impact of emerging health insurance arrangements on diabetes outcomes and disparities: rationale and study design.

6. Case-control Study -Case-control studies begin with the outcomes and do not follow people over time. Researchers choose people with a particular result (the cases) and interview the groups or check their records to ascertain what different experiences they had. They compare the odds of having an experience with the outcome to the odds of having an experience without the outcome.

Example:Non-use of bicycle helmets and risk of fatal head injury: a proportional mortality, case-control study

7. Cross-sectional study -The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.

Example: Fasting might not be necessary before lipid screening: a nationally representative cross-

sectional study

8. Case Reports and Series -A report on a series of patients with an outcome of interest. No control group is involved.

Example: Students mentoring students in a service-learning clinical supervision experience: an educational case report.

9. Ideas, Editorials, Opinions - Put forth by experts in the field.

Example: Health and health care for the 21st century: for all the people.

10. Animal Research Studies -Studies conducted using animal subjects.

Example: Intranasal leptin reduces appetite and induces weight loss in rats with diet-induced obesity (DIO).

11. Lab Research -"Test tube" experiments conducted in a controlled laboratory setting.

Area : Basic Biomedical Sciences

Unit: 1A Physiology

Physiology Of Respiration

Physiology of Respiration

Pulmonary Ventilation

Ventilation is the movement of air into and out of the lungs, as in breathing. There are two phases of ventilation.

1. Inhalation is the drawing of air into the lungs.

2. Exhalation is the expulsion of air from the lungs.

In inhalation, the active phase of breathing, the respiratory muscles contract to enlarge the thoracic cavity.

The diaphragm is a strong dome-shaped muscle attached around the base of the rib cage.

The rib cage is also moved upward and outward by contraction of the external intercostals muscles and, during exertion, by contraction of other muscles of the neck and chest.

During quiet breathing, the movement of the diaphragm accounts for most of the increase in thoracic volume.

As the thoracic cavity increases in size, gas pressure within the cavity decreases. When the pressure drops to slightly below atmospheric pressure, air is drawn into the lungs.

In exhalation, the passive phase of breathing, the muscles of respiration relax, allowing the ribs and diaphragm to return to their original positions. The tissues of the lung are elastic and recoil during exhalation. During forced exhalation, the internal intercoastals muscles and the muscles of the abdominal wall contracts, pulling the bottom of the rib cage in and down. The abdominal viscera are also pushed upward against the diaphragm.

Air Movement

Air enters the respiratory passages and flows through the ever-dividing tubes of the bronchial tree. As the air traverses this passage, it moves more and more slowly through the great number of bronchial tubes until there is virtually no forward flow as it reaches the alveoli.

Here the air moves by diffusion, which soon equalizes any differences in the amounts of gases present.

Each breath causes relatively little change in the gas composition of the alveoli, but normal

continuous breathing ensures the presence of adequate oxygen and the removal of carbon dioxide.

Tidal volume The amount of air moved into or out of the lungs in quiet, relaxed breathing.

Vital capacity The volume of air that can be expelled from the lungs by maximum exhalation following maximum inhalation.

Residual volume The volume of air that remains in the lungs after maximum exhalation.

Total lung capacity

The total volume of air that can be contained in the lungs after maximum inhalation

Functional residual capacity

The amount of air remaining in the lungs after normal exhalation.

Regulation of respiration

• Regulation of respiration is a complex process that must keep pace with moment-to-moment changes in cellular oxygen requirements and carbon dioxide production. Regulation depends primarily on the respiratory control centers located in the medulla and pons of the brain stem. Nerve impulses from the medulla are modified by the centers in the pons.
• Respiration is regulated so that the levels of oxygen, carbon dioxide, and acid are kept within certain limits.
• The control centers regulate the rate, depth, and rhythm of respiration. From the respiratory center in the medulla, motor nerve fibers extend into the spinal cord. From the cervical (neck) part of the cord, these nerve fibers continue through the phrenic nerve to the diaphragm. The diaphragm and the other muscles of respiration are voluntary in the sense that they can be regulated by messages from the higher brain centers, notably the cortex. It is possible for a person to deliberately breath more rapidly or more slowly or to hold his breath and not breath at all for a time.
• Usually we breath without thinking about it, while the respiratory centers in the medulla and pons do the controlling. Of vital importance in the control of respiration are the chemoreceptors. These receptors are found in structures called the carotid and aortic bodies, as well as out side the medulla of the brain stem.
• The carotid bodies are located near the bifurcation of the common carotid arteries, while the aortic bodies are located in the aortic arch. These bodies contain many small blood vessels and sensory neurons, which are vital importance in the control of respiration are the chemoreceptors.
• These receptors are found in structures called the carotid and aortic bodies, as well as out side the medulla of the brain stem.
• The carotid bodies are located near the bifurcation of the common carotid arteries, while the aortic bodies are located in the aortic arch. These bodies contain many small blood vessels and sensory neurons, which are sensitive to decreases in oxygen supply as well as to increases in carbon dioxide and acidity (H+).
• Impulses are sent to the brain from the receptors in the carotid and aortic bodies.
• The receptor cells outside the medulla are affected by the concentration of hydrogen ion in cerebrospinal fluid (CSF) mas determined by the concentrations of carbon dioxide in the blood.

Area 1 - Basic Biomedical Sciences (16%)

1A Physiology

1A01 Lymphatic System

The lymphatic system consists of:

lymph

lymph vessels

lymph nodes

lymph organs, e.g. spleen and thymus

diffuse lymphoid tissue, e.g. tonsils

bone marrow.

Functions of the lymphatic system include the following.

Tissue drainage. 

Every day, 3-4 litres of fluid are drained away by the lymphatic vessels. Without this, the tissues would rapidly become waterlogged, and the cardiovascular system would begin to fail as the blood volume falls.

Absorption in the small intestine. 

Fat and fat-soluble materials, e.g. the fat-soluble vitamins, are absorbed into the central lacteals           (lymphatic vessels) of the villi.

Immunity. 
The lymphatic organs are concerned with the production and maturation of lymphocytes.

The Lympahtic System

lymph.

•  Lymph is a clear watery fluid. Lymph transports the plasma proteins that seep out of the capillary beds back to the bloodstream.
• It also carries away larger particles, e.g. bacteria and cell debris from damaged tissues
• Lymph contains lymphocytes, which circulate in the lymphatic system allowing them to patrol the different regions of the body

Lymph capillaries

• All tissues of the body have a network of lymphatic vessels, with the exception of the central nervous system, the bones and the most superficial layers of the skin.

Larger lymph vessels

• The walls of lymph vessels are about the same thickness as those of small veins and have the same layers of tissue, i.e. a fibrous covering, a middle layer of smooth muscle and elastic tissue and an inner lining of endothelium.
• Lymph vessels have numerous cup-shaped valves which ensure that lymph flows in one way only, i.e. towards the thorax.
• In addition, any structure that periodically compresses the lymphatic vessels can assist in the movement of lymph along the vessels, commonly including the contraction of adjacent muscles and the pulsation of large arteries.

Lymph nodes

•  Lymph nodes are oval or bean-shaped organs that lie, often in groups, along the length of lymph vessels.
•  The lymph drains through a number of nodes, usually 8 to 10, before returning to the venous circulation. These nodes vary considerably in size: some are as small as a pin head and the largest are about the size of an almond.

Spleen

• The Spleen is  formed by reticular and lymphatic tissue and is the largest lymph organ.
• The spleen lies in the left hypochondriac region of the abdominal cavity between the fundus of the stomach and the diaphragm.
•  It is purplish in colour and varies in size in different individuals, but is usually about 12 cm long, 7 cm wide and 2.5 cm thick. It weighs about 200 g.

Functions

Phagocytosis
Old and abnormal erythrocytes are destroyed in the spleen and the breakdown products, bilirubin and iron, are passed to the liver via the splenic and portal veins.

Storage of blood
The spleen contains up to 350 ml of blood, and in response to sympathetic stimulation can rapidly return a large part of this volume to the circulation, e.g. in haemorrhage.

Immune response
The spleen contains T- and B-lymphocytes, which are activated by the presence of antigens, e.g. in infection. Lymphocyte proliferation during serious infection can cause enlargement of the spleen (splenomegaly}.

Erythropoiesis

The spleen and liver are important sites of fetal blood cell production, and the spleen can also fulfil this function in adults in times of great need.

Thymus gland

The thymus gland lies in the upper part of the mediastinum behind the sternum and extends upwards into the root of the neck.

Function

Lymphocytes originate from pluripotent stem cells in red bone marrow. Those that enter the thymus develop into activated T-lymphocytes.

FPGEETutor.com Wishing you a very happy and prosperous Diwali.

Study tables for easy prep.of Fpgee exam

The study Tables are important preaparation tools. They help us in remembering and recollecting the prep.content. please find one sample table:

Prodrugs with their actives forms and clinical uses:-
Prodrug	Active form	Clinical use
Spirinolactone	Canrenone	Steroidal diuretic
Nabumetone	6-methoxy-napthlthalen 2-acetic acid	NSAID
Cyclophosphamide	Ethylaneimonium deri	Antineoplastic
Irinotecan	SN-38	Antineoplastic
Estramustine	Estradiol + Carmustine	Prostate cancer
Amifostine	Dephosphorylated form	Used along with cisplatin in renal  toxicity.
Sulindac	Sulfide form	NSAID
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Lazy lizard source of diabetes drug

Lazy lizard source of diabetes drug: 

The peculiar eating habits of a North American lizard have led to a new drug designed to help people suffering with Type 2 diabetes. Since the lazy lizard, known as the Gila Monster (Heloderma suspectum), spends most of its time doing very little in an underground burrow, it developed a biochemical system for controlling the storage and release of energy. The key to the system is a compound called exendin-4, a hormone found in the lizard's saliva. It slows the creature's digestion, enabling it to get by on just 3 or 4 meals a year. In 2005, the U.S. Food and Drug Administration approved the drug exenatide (marketed as Byetta®) for the management of type 2 diabetes. It is a synthetic version of a protein, exendin-4, derived from the Gila monster's saliva, manufactured and marketed by the international drug giant Eli Lilly.

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New Sources for Drug discovery-Really astonishing’-

New Sources for Drug discovery-Really astonishing’-

Eptifibatide is a cyclic heptapeptide derived from a protein found in the venom of the southeastern pygmy rattlesnake (Sistrurus miliarius barbouri). It belongs to the class of the so-called arginin-glycin-aspartat-mimetics and reversibly binds to platelets. Integrilin® is sold in two strengths, globally: vials containing 2 mg/ml (20 mg totally) and 0.75 mg/ml (75 mg totally). A third size is sold in the US: 100 ml vials containing 2 mg/ml (200 mg totally). Eptifibatide is a cyclic heptapeptide containing 6 amino acids and 1 mercaptopropionyl (des-amino cysteinyl) residue. Each 10-mL vial contains 2 mg/mL of INTEGRILIN and each 100-mL vial contains either 0.75 mg/mL of INTEGRILIN or 2 mg/mL of INTEGRILIN.

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