A bacterium undergoing sporulation will first replicate its DNA ,The replicated DNA as well as a small amount of cytoplasm is segregated at one end of the cell,The plasmid membrane of the bacterium then grows inwards to eventually separate replicated DNA and the surrounding cytoplasm from the rest of the cells. water diffuses from this small segregated portion into the surrounding cell and then new endospore develops a thick protein coat once the formation of the endospore is complete the original cell wall dissolves and parent cell dies. the endospore is released from the dead parent cell
Probiotics are dietary supplements and live microorganisms containing potentially beneficial bacteria or yeasts. According to the currently adopted definition by FAO/WHO, probiotics are: ‘Live microorganisms which when administered in adequate amounts confer a health benefit on the host’.
Lactic acid bacteria (LAB) are the most common type of microbes used. LAB have been used in the food industry for many years, because they are able to convert sugars (including lactose) and other carbohydrates into lactic acid. This not only provides the characteristic sour taste of fermented dairy foods such as yogurt, but also by lowering the pH may create fewer opportunities for spoilage organisms to grow, hence creating possible health benefits on preventing gastrointestinal infections.Strains of the genera Lactobacillus and Bifidobacterium, are the most widely used probiotic bacteria.
Probiotic bacterial cultures are intended to assist the body's naturally occurring gut flora, an ecology of microbes, to re-establish themselves. They are sometimes recommended by doctors, and, more frequently, by nutritionists, after a course of antibiotics, or as part of the treatment for gut related candidiasis. In these cases, the bacteria that work well with our bodies (see symbiosis) may decrease in number, an event which allows harmful competitors to thrive, to the detriment of our health. Claims are made that probiotics strengthen the immune system to combat allergies, excessive alcohol intake, stress, exposure to toxic substances, and other diseases.
Maintenance of a healthy gut flora is, however, dependent on many factors, especially the quality of food intake.
Asexual reproduction is a form of reproduction where one parent is involved.A more stringent definition is agamogenesis which refers to reproduction without the fusion of gametes. Asexual reproduction is the primary form of reproduction for single-celled organisms such the archaea, bacteria, and protists. Many plants and fungi reproduce asexually as well.
Almost all bacterial cells reproduce by binary fission. As the term suggest this is process by which a single cell simply splits into two creating 2 identical copies of itself .the first step in this process is replication, At the replication stage bacteria increases in size and makes an exact duplicate of its chromosome following this bacteria begins to elongate and pinch off in the center. The two chromosomes moved to opposing sides of the cell and the cell wall grows to fill in the gap in the center. This results in two separate yet identical cells that are an exact match of the original parent cell
Maraviroc is a drug used in the treatment of HIV infection.Maraviroc is an entry inhibitor. Specifically, maraviroc blocks the chemokine receptor CCR5 which HIV uses as a co receptor to bind and enter a human helper T cell. Because HIV can also use another co receptor, CXCR4, an HIV tropism test such as a trofile assay must be performed to determine if the drug will be effective.
The first step in HIV1 life cycle is viral attachment to the CD4 T-cell surface, the next step is viral entry which involves a cascade of molecular interactions between the viral envelope glycoprotein and two T-cell surface receptors, a primary receptor and a co-receptor. The GP 120 subunit of the envelope protein first binds the CD4 primary receptor this induces a conformational change in GP 120 that allows the co-receptor binding this Binding triggers conformational changes in the GP 41 subunit leading to insertion of its N-terminal fusion peptide into the host cell's membrane.Fusion results release of the viral genome into the cytoplasm .the co-receptors are the members of the superfamily of G-protein coupled receptors over more than a dozen types of co-receptors have been described .But only two co-receptors such as areas of the CCR5 and CXCR4 are used by all HIV-1 strains.
The co-receptors play a crucial role in HIV disease became evident when the common mutational variant of the CCR5 coding gene known as Delta 32 was discovered in 1996 This CCR5 genetic variant results in the production of nonfunctional CCR5 co receptors .The persons with two normal copies of the CCR5gene predominates in the population and are susceptible to HIV infection.The persons who inherit two copies of the CCR5 delta 32 variant from their parents known as delta 32 homozygotes of non functional CCR5 co receptors are appear to be highly resistant to HIV infection.Delta 32 homozygotes that appears not to be associated with any significant deleterious effects. Delta 32 heterozygotes inherit one copy of the CCR5 delta 32 variant from one parent in the normal form of the CCR5gene from the other parent, Delta 32 heterozygotes can become infected with HIV disease progression is significantly delayed compared to those who have two normal copies of the CCR5 gene. To be effective the co receptor antagonist must be directed at a specific co-receptor CCR5 ,THE co-receptor antagonist for example functions by binding specifically to the CCR5 co receptor molecule, The bound co-receptor is blocked from binding the viral GP 120 subunit which prevents the conformational changes on GP 41 which prevents viral particle entry and HIV particles are unable to enter the T cell cannot infected and cannot replicate. Different HIV strains vary in their ability to use the major co-receptors to achieve entry into the host cell some HIV strains easily use CCR5 co receptor summoning the CX Cr4 for a receptor while other viruses geotropic use both. In HIV-infected individual may have only the CCR5 using virus or the CXCR4 using virus or a mixture of CCR5 using CXCR4 using duo tropic viruses.In the early phase of infection the CCR5 using virus predominates in most patients in the late phase of infection HIV strains capable of using CXCR4 recptoe. Unlike reverse transcripase or protease inhibitors which went inside the infected cell to receptor ,Antagonists function on the outside of the host cell,The co-receptor antagonists are therefore classified as entry inhibitors. the mechanism of action of co-receptor antagonists differs from other antiretroviral in a very important way rather than binding to viral proteins this new class prevents viral replication by binding to human cells such as T cells and macrophages this unique mechanism has potential clinical advantages.
Deoxyribonucleic acid (DNA) is a nucleic acid molecule consisting of long chains of polymerized (deoxyribo) nucleotides. In double-stranded DNA the two strands are held together by hydrogen bonds between complementary nucleotide base pairs.
DNA was discovered in 1869 by Johann Friedrich Miescher, a Swiss biochemist working in Tubigen, Germany, The first extracts that Miescher made from human white blood cells were crude mixtures of DNA and chromosomal proteins. Next year he prepared a pure sample of nucleic acid from Salomon sperm, The chemical test showed that DNA is acidic and rich in phosphorus, and also suggested that the individual molecules are very large, although it was not until the 1930s when biophysical techniques are applied to DNA that huge lengths of polymeric chains were fully appreciated.
The basic building block of nucleic acids is the nucleotide. This has three components:
a nitrogenous base;
a sugar;
and a phosphate.
The nitrogenous base is a purine or pyrimidine ring. The base is linked to position 1 on a pentose sugar by a glycosidic bond from N1 of pyrimidines or N9 of purines. To avoid ambiguity between the numbering systems of the heterocyclic rings and the sugar, positions on the pentose are given a prime ().
Nucleic acids are named for the type of sugar; DNA has 2–deoxyribose, whereas RNA has ribose. The difference is that the sugar in RNA has an OH group at the 2 position of the pentose ring. The sugar can be linked by its 5 or 3 position to a phosphate group.
A nucleic acid consists of a long chain of nucleotides. the backbone of the polynucleotide chain consists of an alternating series of pentose (sugar) and phosphate residues. This is constructed by linking the 5 position of one pentose ring to the 3 position of the next pentose ring via a phosphate group. So the sugar-phosphate backbone is said to consist of 5–3 phosphodiester linkages. The nitrogenous bases "stick out" from the backbone.
Each nucleic acid contains 4 types of base. The same two purines, adenine and guanine, are present in both DNA and RNA. The two pyrimidines in DNA are cytosine and thymine; in RNA uracil is found instead of thymine. The only difference between uracil and thymine is the presence of a methyl substituent at position C5. The bases are usually referred to by their initial letters. DNA contains A, G, C, T, while RNA contains A, G, C, U.
The terminal nucleotide at one end of the chain has a free 5 group; the terminal nucleotide at the other end has a free 3 group. It is conventional to write nucleic acid sequences in the 5→3 direction—that is, from the 5 terminus at the left to the 3 terminus at the right.
The replication process is initiated at particular points within the DNA, known as "origins", which are targeted by proteins that separate the two strands and initiate DNA synthesis.Origins contain DNA sequences recognized by replication initiator proteins (eg. dnaA in E coli' and the Origin Recognition Complex in yeast). These initiator proteins recruit other proteins to separate the two strands and initiate replication forks.
Initiator proteins recruit other proteins to separate the DNA strands at the origin, forming a bubble. Origins tend to be "AT-rich" (rich in adenine and thymine bases) to assist this process because A-T base pairs have two hydrogen bonds (rather than the three formed in a C-G pair)—strands rich in these nucleotides are generally easier to separate. Once strands are separated, RNA primers are created on the template strands and DNA polymerase extends these to create newly synthesized DNA.
As DNA synthesis continues, the original DNA strands continue to unwind on each side of the bubble, forming replication forks. In bacteria, which have a single origin of replication on their circular chromosome, this process eventually creates a "theta structure" (resembling the Greek letter theta: θ). In contrast, eukaryotes have longer linear chromosomes and initiate replication at multiple origins within these.
The replication fork
The replication fork is a structure which forms when DNA is being replicated. It is created through the action of helicase, which breaks the hydrogen bonds holding the two DNA strands together. The resulting structure has two branching "prongs", each one made up of a single strand of DNA.
Leading strand synthesis
In DNA replication, the leading strand is defined as the new DNA strand at the replication fork that is synthesized in the 5'→3' direction in a continuous manner. When the enzyme helicase unwinds DNA, two single stranded regions of DNA (the "replication fork") form. On the leading strand DNA polymerase III is able to synthesize DNA using the free 3' OH group donated by a single RNA primer and continuous synthesis occurs in the direction in which the replication fork is moving.
Lagging strand synthesis
The lagging strand is the DNA strand at the opposite side of the replication fork from the leading strand, running in the 3' to 5' direction. Because DNA polymerase cannot synthesize in the 3'→5' direction, the lagging strand is synthesized in short segments known as Okazaki fragments. Along the lagging strand's template, primase builds RNA primers in short bursts. DNA polymerases are then able to use the free 3' OH groups on the RNA primers to synthesize DNA in the 5'→3' direction. The RNA fragments are then removed (different mechanisms are used in eukaryotes and prokaryotes) and new deoxyribonucleotides are added to fill the gaps where the RNA was present. DNA ligase then joins the deoxyribonucleotides together, completing the synthesis of the lagging strand.
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Endometrium is the inside lining of the uterus,Endometrial Biopsy is the removal of the sample of the tissue from the endometrium for testing ,A biopsy may be done for examine the cells are where cancer or precancerous cells,to determine the cause of irregular bleeding or to investigate fertility problems,this procedure also used find infection and monitor medication effectiveness
The patient will be asked to undress and lie on the table with her feet in the stirrups for a pelvic examination. She may or may not be given localized anesthesia.
A speculum will be inserted into the vagina to spread the walls of the vagina apart to expose the cervix.The cervix will then be cleansed with an antiseptic solution.
A tenaculum, a type of forceps, will hold the cervix steady for the biopsy.
A pipelle, a thin tube also called a catheter, will be inserted into the uterus. A smaller tube (internal piston) inside the pipelle will be withdrawn to create suction. The pipelle be will rotated and moved in and out to collect small pieces of endometrial tissue. Cramping may occur.
The removed tissue will be placed in a preservative.
The tissue will be sent to a laboratory, where it will be processed and tested. It will then be read microscopically by a pathologist who will determine the diagnosis
Heralded as the future of medicine, personalized medicines seem to be the answer for making therapeutics more likely to be highly effective and safer. Join Deanna Kroetz of UCSF's School of Pharmacy and learn about macromolecular therapeutics, their promise, their limitations.
Pharmacogenetics is the study or clinical testing of genetic variation that gives rise to differing response to drugs.Much of current clinical interest is at the level of pharmacogenetics, involving variation in genes involved in, drug metabolism with a particular emphasis on improving drug safety. The wider use of pharmacogenetic testing is viewed by many as an outstanding opportunity to improve prescribing safety and efficacy. Driving this trend are the 106,000 deaths and 2.2 Million serious events caused by adverse drug reactions in the US each year (Lazarou 1998). As such ADRs are responsible for 5-7% of hospital admissions in the US and Europe, lead to the withdrawal of 4% of new medicines and cost society an amount equal to the costs of drug treatment (Ingelman-Sundberg 2005). Comparisons of the list of drugs most commonly implicated in adverse drug reactions with the list of metabolizing enzymes with known polymorphisms found that drugs commonly involved in adverse drug reactions were also those that were metabolized by enzymes with known polymorphisms
Blood pressure or BP is the pressure exerted by the flow of blood on the walls of the arteries; it is determined by the force and amount blood pumped by the heart and by diameter of the arteries. it consist of the two components systolic pressure and diastolic pressure, these are normally 120/80 mgof mercury respectively, when the blood pressure exceed these value it leads to a condition called high blood pressure or hypertension, there are two types of hypertension primary hypertension and secondary hypertension, primary hypertension is without specific identifiable cause, secondary hypertension is elevated blood pressure that results from underlying identifiable often correctable cause, only about 5 to10 % hypertension cases are thought to result from secondary causes, the most common causes of the secondary hypertension are kidney disease ,adrenal gland disease, narrowing of the aorta and sleep apnea, Hypertension common symptoms are Headache,Dizziness,Blurred vision, and in severe cases confusion and coma are possible. Small portable instruments called a sphygmomanometer usually measure Blood pressure, It consist of an air pump, pressure gauge and rubber cuff. The instrument measures the blood pressure in units called millimeter of mercury (mmhg). A blood pressure reading of 120/80mmHg is considered normal, where as the blood pressure of 140/90mmHg or higher is considered High Blood pressure or Hypertension
Most of the secondary mechanisms associated with hypertension are generally fully understood, and are outlined at secondary hypertension. However, those associated with essential (primary) hypertension are far less understood. What is known is that cardiac output is raised early in the disease course, with total peripheral resistance (TPR) normal; over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:
Inability of the kidneys to excrete sodium, resulting in natriuretic factors such as Atrial Natriuretic Factor being secreted to promote salt excretion with the side-effect of raising total peripheral resistance.
An overactive renin / angiotensin system leads to vasoconstriction and retention of sodium and water. The increase in blood volume leads to hypertension.
An overactive sympathetic nervous system, leading to increased stress responses.
It is also known that hypertension is highly heritable and polygenic (caused by more than one gene) and a few candidate genes have been postulated in the etiology of this condition.
Prevention:
Prevention of hypertension only goes as far as the cause; one can adjust lifestyle related causes but genetics, race, age and gender are outside the realm of change.
Modifiable factors include diet, weight-loss, exercise and stress management.
Low-sodium and low-fat diets can reduce cardiovascular risks and keep arteries clear of plaque and blood volume at normal levels.
Losing even 10% of body weight can have fantastic benefits towards health, including reversal or prevention of HTN, dropping systolic pressures several points.
Exercise maintains a healthy heart, thus healthy cardiac contractions and functions. The heart is a muscle too, working out the cardiac muscles makes the heart beat more efficiently, thus pumping blood around the body more effectively.
Stressors can negatively affect blood pressure by activating the sympathetic nervous system, thus fight or flight responses which increase heartrate and blood pressure. Chronic stress can lead to regular and frequent activation of the system and repeated high blood pressure.
Effective management of stress can reduce this particular risk.
Natural selection is the process by which favorable heritable traits become more common in sucessiove genrations of a population of reproducing organisms,and unfavorable heritable traits become less common, due to differntial reproduction of genotypes,Natural selection acts on the phenotype, or the observable characteristics of an organism, such that individuals with favorable phenotypes are more likely to survive and reproduce than those with less favorable phenotypes. The phenotype's genetic basis, genotype associated with the favorable phenotype, will increase in frequency over the following generations. Over time, this process may result in adaptations that specialize organisms for particular ecological niches and may eventually result in the emergence of new species. In other words, natural selection is the mechanism by which evolution may take place in a population of a specific organism.The term was introduced by Charles Darwin in his groundbreaking 1859 book The Origin of Species in which natural selection was described by analogy to artificial selection, a process by which animals with traits considered desirable by human breeders are systematically favored for reproduction. The concept of natural selection was originally developed in the absence of a valid theory of inheritance; at the time of Darwin's writing, nothing was known of modern genetics. Although Gregor Mendel, the father of modern genetics, was a contemporary of Darwin's, his work would lie in obscurity until the early 20th century. The union of traditional Darwinian evolution with subsequent discoveries in classical and molecular genetics is termed the modern evolutionary synthesis. Although other mechanisms of molecular evolution, such as the neutral theory advanced by Motoo Kimura, have been identified as important causes of genetic diversity, natural selection remains the single primary explanation for adaptive evolution.
This lecture was conducted by Dr.Bisola 0 0jikutu MD M.P.H Director of the Office of International Programs Division of AIDS, Harvard Medical School,She working has a infectious disease specialist ,concentrating on AIDs disease.She talks about HIV Drugs and HIV Evolution (how HIV got resistant against hiv drugs) and various anti-retroviral drugs, such as AZT,Protease inhibitor and HAART and its mechanism ,which had been used to prevent HIV infection. She also tells how Hiv became resistant to these drugs and concludes with latest HIV drug MARAVIROC and how it might prevent HIV infection
Most people who are infected with Hiv virus will develop AIDS, The Disease is caused by decrease in Helper T cells count and increase in viral level. Once they develop Aids the Patient will have opportunistic infection. And eventually leads to death.To stop the disease the viral replication should stopped.
Aids infection was first noticed in 1981 and virus was Cultured 1983 .In 1985 commercial test done to detect Hiv antibody, After 6 years medication for HIV is found,The Medication was called AZT (azidothymidine), so what is AZT .
AZT
AZT is a similar analog of thiamine, which is building block of DNA.Difference between AZT and thymine is that AZT has azide side chain rather than hydroxyl chain of thyimidine.
History of AZT
Back in 1960s AZT was synthesized for treating cancer, but it Was unable to prevent cancer, so it was put is shelf, and When HIV came researchers thought "y don't we try this drug for treating HIV”.
Mode of Action of AZT
Generally HIV RNA reverse transcribed to a growing strand DNA, During reverse transcription nucleotides bind to this Growing strand of DNA,When AZT comes in, it looks like a nucleotide ,and binds to the hydroxyl group, But it has azide side chain which blocks further extension of the chain because of this other nucleotides cannot bind to it.
AZT Clinical trial
In Phase 1 AZT clinical trial, they had given AZT to HIV patients for six weeks, they found significant increase of T-helper cells in patient. In phase 2 trials AZT was compared to placebo(a inactive drug that generally used for comparison) In this patients with AZT had low proportion of opportunistic infection than people who had taken placebo.The striking thing in trial is mortality rate, In treatment group who took AZT 1 in 145 people died,but in placebo group 16 out of 137 people died. After 7 months researchers halted the Trial and unblinded it(now patients and researchers now know which drug they are taking) and because of the striking result everybody started to have AZT .The problem with drug was there was increase in Viral level after 22 weeks, that is HIV got resisted to this drug after 22 weeks.
AZT Resistance
The reason behind the HIV got resistant against AZT is that ,when HIV RNA is reverse transcribed to the growing DNA strand,Reverse trascriptase makes lot of errors,so in patients blood we can see lot mutant HIV Virus,so when AZT is given to patients it lowers the amount virus in the blood, But the virus is still replicates it doesn't lowers enough,When you keepon giving the drug ,under the selective pressure HIV virus starts developing more resistant virus.
Protease Enzyme
When HIV buds from the cell, it is not in the matured form,protease enzyme cleves the this unmatured protein in several places so the unmaturatured protein undergoes confirmation changes to make matured HIV virus
Mode of Action of Protease inhibitor
When protease inhibitor enters into cell , The inhibitor bind to the active site in protease enzyme,because of this protease enzymes is unable to cleave the proteins,which inturn result on-maturation of HIV virus
HAART therapy:
Two drugs won't for very long in preventing HIV, So if u give three dugs (2 of AZT type+1 protease inhibitor) we can see sustained decrease in HIV virus in blood and increase in T-helper cells level
CCR5
Researcher found that Certain people are not affected by HIV though they had repeated exposure to HIV virus. One hypothesis researchers told These people would have some genetic mutation in immune system, which stops HIV to entering into the cells. Researchers found that these people had small CCR5 receptor (chemokine co-receptor) in T-helper cells, which makes HIV not able to enter the cell. This makes to good drug target,If we able to inhibit CCR5 receptor then HIV virus will be unable to enter the cell.
Semi conservative replication is a normal process of DNA synthesis, in which the two original strands of the molecule separate, and each acts as a template on which a new complementary strand is laid down.
The genetic information in a bacterial cell is stored in the form of a double stranded covalently closed circle of DNA; Replication begins at a specific site called the origin. The origin replicates and then DNA replication proceeds in two directions, the two original strands shown as solid lines serve as the templates for synthesis of new strands, shown as dotted line, this refereed to as semi conservative replication
Synaptic transmission is the process whereby one neuron (nerve cell) communicates with other neurons or effectors, such as a muscle cell, at a synapse. A typical neuron has a cell body (soma), branching processes specialized to receive incoming signals (dendrites), and a single process (axon) that carries electrical signals away from the neuron toward other neurons or effectors. Electrical signals carried by axons are action potentials. Axons often have thousands of terminal branches, each ending as a bulbous enlargement, the synaptic knob or synaptic terminal. At the synaptic knob, the action potential is converted into a chemical message which, in turn, interacts with the recipient neuron or effector. This process is synaptic transmission.
Information has to travel from one neuron to next, it must be transferred across synaptic cleft, neuro transmitters are chemical messengers that bridge the gap formed by synapes, neurotransmitters are stored in synaptic vesicles at the end of axons. As the action potential reaches the terminal end of the axon, calcium influx through the calcium channels causes these vesicles to fuse with pre-synaptic membrane, the vesicles then dump their contents which are neuro transmitters into the synaptic cleft, the neuro transmitters then diffuse with the post synaptic membrane and bind to specific receptors, however neuro transmitters only act for the brief time, their action is terminated by reuptake pumps that force neurotransmitters back into axon terminal or sometimes by enzymatic degradation in the synaptic cleft ,this removes the neurotransmitters from the synaptic cleft and terminates its effect on post synaptic membrane. Animation showing neurotransmission across the synaptic cleft.
Th Origin species was published in year 1859 by Charles Darwin ,It introduced the theory that populations evolve over the course of generations through a process of natural selection,Darwin's book was the culmination of evidence he had accumulated on the voyage of the Beagle in the 1830s and expanded through continuing investigations and experiments after his return.
Darwin's theory is based on key observations and inferences drawn from them:
Species have great fertility. They have more offspring than can grow to adulthood.
Populations remain roughly the same size, with small changes.
Food resources are limited, but are relatively stable over time.
An implicit struggle for survival ensues.
In sexually reproducing species, generally no two individuals are identical.
Some of these variations directly impact the ability of an individual to survive in a given environment.
Much of this variation is inheritable.
Individuals less suited to the environment are less likely to survive and less likely to reproduce, while individuals more suited to the environment are more likely to survive and more likely to reproduce.
The individuals that survive are most likely to leave their inheritable traits to future generations.
This slowly effected process results in populations that adapt to the environment over time, and ultimately, after interminable generations, these variations accumulate to form new varieties, and ultimately, new species.
Glaucoma is a group of diseases of the optic nerve involving loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. Although raised intraocular pressure is a significant risk factor for developing glaucoma, there is no set threshold for intraocular pressure that causes glaucoma. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressure for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.
Glaucoma has been nicknamed the "sneaky thief of sight" because the loss of visual field often occurs gradually over a long time and may only be recognized when it is already quite advanced. Once lost, this damaged visual field can never be recovered. Worldwide, it is the second leading cause of blindness. Glaucoma affects one in two hundred people aged fifty and younger, and one in ten over the age of eighty.
The major risk factor for most glaucomas and focus of modeling and treatment is increased intraocular pressure. Intraocular pressure is a function of production of liquid aqueous humor by the ciliary body of the eye and its drainage through the trabecular meshwork. Aqueous humor flows from the ciliary bodies into the posterior chamber, bounded posteriorly by the lens and the zonule of Zinn and anteriorly by the iris. It then flows through the pupil of the iris into the anterior chamber, bounded posteriorly by the iris and anteriorly by the cornea. From here the trabecular meshwork drains aqueous humor via Schlemm's canal into scleral plexuses and general blood circulation. In open angle glaucoma there is reduced flow through the trabecular meshwork; in angle closure glaucoma, the iris is pushed forward against the trabecular meshwork, blocking fluid from escaping.
The inconsistent relationship of glaucomatous optic neuropathy with ocular hypertension has provoked hypotheses and studies on anatomic structure, eye development, nerve compression trauma, optic nerve blood flow, excitatory neurotransmitter, trophic factor, retinal ganglion cell/axon degeneration, glial support cell, immune, and aging mechanisms of neuron loss.
Column chromatography in chemistry is a method used to purify individual chemical compounds from mixtures of compounds. It is often used for preparative applications on scales from micrograms up to kilograms.
The classical preparative chromatography column is a glass tube with a diameter from 5 to 50 mm and a height of 50 cm to 1 m with a tap at the bottom. A slurry is prepared of the eluent with the stationary phase powder and then carefully poured into the column. Care must be taken to avoid air bubbles. A solution of the organic material is pipetted on top of the stationary phase. This layer is usually topped with a small layer of sand or with cotton or glass wool to protect the shape of the organic layer from the velocity of newly added eluant. Eluant is slowly passed through the column to advance the organic material. Often a spherical eluent reservoir or an eluent-filled and stoppered separating funnel is put on top of the column.
Subscribe in a reader Steps involved: During chromatography support or matrix is placed in the column,the support is equilibrated with the buffer which is generally identical to buffer in which the sample is dissolved
and sample is applied to the column,in most chromotograhy protocols the protein of interest along with the protein impurities in the sample find to the matrix,the impuritis are washed away by the buffer ,which usually the same buffer which is used in equilibration,then sample is then eluded and collected by washed with appropriate buffer,if teh single buffer is used the process is reffered to as isocratic separation,if multiple buffers are used its is called has gradient,the support is then washed by regeneration buffer that prepares th column for further use and storage with exception of gel filteration ,this basic protocal is used
Anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicyclomine. Generally speaking, it reduces the effects mediated by acetylcholine on acetylcholine receptors in neurons through competitive inhibition. The effect is therefore reversible.
By blocking parasympatc neruo transmittor acetocholine ,anti-cholorinergic drugs promote bronchoconstrictiction,the vagus nerve along the airways release acetylcholine which binds with muscarinic receptors in the smooth muscle and airway sub mucosal glands,by blocking acetylcholine anticholiergics contradict bronchoconstriction
National Symposium on HIV/AIDS Prevention & Transmission 2007, you will hear from experts from universities throughout the US and from South Africa, updating us on their latest research and findings. Join Eliezer Masliah, MD, University of California, San Diego, as he presents on Changing Aspects of the Neuropathogenesis of HIV in the HAART Era.
Diagnostic pelvic laproscopy is used to examine the internal organs of pelvis in an effort to identify the specific problem,he may advised to undergo diagnostic laproscpy for example if u have Pelvic pain or mass,an abnormal accumulation of fluid or difficulty in becoming pregnant. Laparoscopy is usually performed under general anesthesia; however it can be performed with other types of anesthesia that permit the patient to remain awake.
The typical pelvic laparoscopy involves a small (1/2" to 3/4") incision in the belly button or lower abdomen. The abdominal cavity is filled with carbon dioxide. Carbon dioxide causes the abdomen to swell which lifts the abdominal wall away from the internal organs, so the doctor has more room to work.
Next, a laparoscope (a one-half inch fiber-optic rod with a light source and video camera) is inserted through the belly button. The video camera permits the surgeon to see inside the abdominal area on video monitors located in the operating room.
Depending on the reason for the laparoscopy, the physician may perform surgery through the laparoscope by inserting various instruments into the laparoscope while using the video monitor as a guide. The video camera also allows the surgeon to take pictures of any problem areas he discovers.
Cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light. Early in the development of age-related cataract the power of the lens may be increased, causing near-sightedness (myopia), and the gradual yellowing and opacification of the lens may reduce the perception of blue colours. Cataracts typically progress slowly to cause vision loss and are potentially blinding if untreated.
Senile cataract, occurring in the aged, is characterized by an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency.
Moreover, with time the cataract cortex liquefies to form a milky white fluid in a Morgagnian cataract, which can cause severe inflammation if the lens capsule ruptures and leaks. Untreated, the cataract can cause phacomorphic glaucoma. Very advanced cataracts with weak zonules are liable to dislocation anteriorly or posteriorly. Such spontaneous posterior dislocations (akin to the historical surgical procedure of couching) in ancient times were regarded as a blessing from the heavens, because some perception of light was restored in the cataractous patients.
Causes
Cataracts develop from a variety of reasons, including long-term exposure to ultraviolet light, exposure to radiation, secondary effects of diseases such as diabetes, hypertension and advanced age, or trauma (possibly much earlier); they are usually a result of denaturation of lens protein. Genetic factors are often a cause of congenital cataracts and positive family history may also play a role in predisposing someone to cataracts at an earlier age, a phenomenon of "anticipation" in pre-senile cataracts.
Bupropion is an atypical antidepressant that acts as a norepinephine and dopamine reuptake inhibitor, and nicotinic antagonist ,Initially researched and marketed as an antidepressant, bupropion was subsequently found to be effective as a smoking cessation aid.
Bupropion reduces the severity of nicotine cravings and withdrawal symptoms. After a seven-week treatment, 27% of subjects who received bupropion reported that an urge to smoke was a problem, versus 56% of those who received placebo. In the same study, 21% of the bupropion group reported mood swings, versus 32% of the placebo group. The bupropion treatment course lasts for seven to twelve weeks, with the patient halting the use of tobacco about ten days into the course. The efficacy of bupropion is similar to that of nicotine replacement therapy. Bupropion approximately doubles the chance of quitting smoking successfully after three months. One year after the treatment, the odds of sustaining smoking cessation are still 1.5 times higher in the bupropion group than in the placebo group. The combination of bupropion and nicotine appears not to further increase the cessation rate. In a direct comparison, varenicline (Chantix) showed superior efficacy: after one year, the rate of continuous abstinence was 10% for placebo, 15% for bupropion, and 23% for varenicline. Bupropion slows the weight gain that often occurs in the first weeks after quitting smoking (after seven weeks, the placebo group had an average 2.7 kg increase in weight, versus 1.5 kg for the bupropion group). With time, however, this effect becomes negligible (after 26 weeks, both groups recorded an average 4.8 kg weight gain).
Activity of Bupropionins
Bupropionis may further improve smoking cessation succesfully rate, Nicotine facilitates norpnephron and dopamine release in the central nervous system bupropion mares nicotine by inhibiting norodrenaline and dopamine reuptake a process that some researchers believe alters nicotine withdrawal symptoms. Pulmonary rehabilitation involves education and exercise aimed at improving patient’s quality of life eliminating COPD burden
Prof.Stephen Nowicki professor of Biology in Duke University tells about How Things Get Done in the Cell especially about protein studies,Proteomics is one of the important part in biotechnolgical studies,hop this lecture is useful.
