Sunday, August 30, 2009

Eye Diseases

Eye Diseases
Some eye problems are minor and fleeting. But some lead to a permanent loss of vision. Common eye problems include
Cataracts - clouded lenses
Glaucoma - damage to the optic nerve from too much pressure in the eye
Retinal disorders - problems with the nerve layer at the back of the eye
Conjunctivitis - an infection also known as pinkeye

Your best defense is to have regular checkups, because eye diseases do not always have symptoms. Early detection and treatment could prevent vision loss. See an eye care professional right away if you have a sudden change in vision or everything looks dim or if you see flashes of light. Other symptoms that need quick attention are pain, double vision, fluid coming from the eye and inflammation.

At the age of 6, one child out of three has ametropia. This word refers to well-known disorders such as long-sightedness, astigmatism and short-sightedness. They can affect one eye or both of them. These disorders are easily corrected ! Besides, some can disappear as we get older, such as long-sightedness.

Long-sightedness :
The eye is too short : the image which is received gets impressed behind the retina and not on it. The eye needs to compensate by permanent accommodation which tires it.

Short-sightedness :
The eye is too long : the image which is received gets impressed in front of the retina and not on it. The distance between the retina and the cornea is too big and the eyes cannot focus on distant objects.
Astigmatism : The curvature of the cornea is very irregular. Instead of being round, it is oval, like a rugby ball ! In some rarer cases astigmatism is due to a fault in the crystalline lens. In both cases the objects appear distorted.

Maintaining Good Eyesight

Good eyesight plays an important role in your mobility and the enjoyment of life, so it's important to follow these basic steps to keep your eyes seeing clearly.

Visit Your Eye Doctor
You should visit your eye doctor for an eye exam at least once every one to two years to help maintain good eyesight. See your ophthalmologist if you experience eye infections or symptoms of disease like loss of or blurred vision, light flashes, eye pain, redness, itching, swelling and irritation around the eye or eyelid.

Practice Disease Prevention
Disease of the eye is the number one cause of blindness. Most diseases that cause blindness, like glaucoma and diabetes, can be treated or their progression slowed down with the proper diagnosis and management. While there is no cure for some eye conditions, there have been major medical advances for age-related macular degeneration, glaucoma, and cataracts. By visiting your eye doctor on a regular basis, you can catch any eye problems in their early stage when they are easier to treat.

Protect Your Eyes From the Sun's Harmful Rays
Constant exposure to ultraviolet light can damage your eyes. Too much exposure increases pigmentation in the eye, causing a discoloration known as "brown" or "sunshine" cataracts. Some eye diseases, such as macular degeneration, have been linked to UV exposure.

Wear Protective Gear and Eyewear During Work and Sporting Events
Wearing safety glasses and protective goggles while playing sports or working with hazardous and air-born materials lowers your risk for eye injury, impaired vision and complete loss of sight.

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Protein synthesis

is the process in which cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription of nuclear DNA into messenger RNA which is then used as input to translation.

The cistron DNA is transcribed into a variety of RNA intermediates. The last version is used as a template in synthesis of a polypeptide chain. Proteins can often be synthesized directly from genes by translating mRNA. When a protein is harmful and needs to be available on short notice or in large quantities, a protein precursor is produced. A proprotein is an inactive protein containing one or more inhibitory peptides that can be activated when the inhibitory sequence is removed by proteolysis during posttranslational modification. A preprotein is a form that contains a signal sequence (an N-terminal signal peptide) that specifies its insertion into or through membranes; i.e., targets them for secretion. The signal peptide is cleaved off in the endoplasmic reticulum.. Preproproteins have both sequences (inhibitory and signal) still present.

For synthesis of protein, a succession of tRNA molecules charged with appropriate amino acids have to be brought together with an mRNA molecule and matched up by base-pairing through their anti-codons with each of its successive codons. The amino acids then have to be linked together to extend the growing protein chain, and the tRNAs, relieved of their burdens, have to be released. This whole complex of processes is carried out by a giant multimolecular machine, the ribosome, formed of two main chains of RNA, called ribosomal RNA (rRNA), and more than 50 different proteins. This molecular juggernaut latches onto the end of an mRNA molecule and then trundles along it, capturing loaded tRNA molecules and stitching together the amino acids they carry to form a new protein chain.

Protein biosynthesis, although very similar, is different for prokaryotes and eukaryotes.

Amino acids

Amino acids are the monomers which are polymerized to produce proteins. Amino acid synthesis is the set of biochemical processes (metabolic pathways) which build the amino acids from carbon sources like glucose.

Many organisms have the ability to synthesize only a subset of the amino acids they need. Adult humans, for example, need to obtain 8 of the 20 amino acids from their food.


Simple diagram of transcription elongationIn transcription an mRNA chain is generated, with one strand of the DNA double helix in the genome as template. This strand is called the template strand. Transcription can be divided into 3 stages: Initiation, Elongation and Termination, each regulated by a large number of proteins such as transcription factors and coactivators that ensure the correct gene is transcribed.

The DNA strand is read in the 3' to 5' direction and the mRNA is transcribed in the 5' to 3' direction by the RNA polymerase.

Transcription occurs in the cell nucleus, where the DNA is held. The DNA structure is two helixes made up of sugar and phosphate held together by the bases. The sugar and the phosphate are joined together by covalent bond. The DNA is "unzipped" by the enzyme helicase, leaving the single nucleotide chain open to be copied. RNA polymerase reads the DNA strand from 3 prime (3') end to the 5 prime (5') end, while it synthsizes a single strand of messenger RNA in the 5' to 3' direction. The general RNA structure is very similar to the DNA structure, but in RNA the nucleotide uracil takes the place that thymine occupies in DNA. The single strand of mRNA leaves the nucleus through nuclear pores, and migrates into the cytoplasm.

The first product of transcription differs in prokaryotic cells from that of eukaryotic cells, as in prokaryotic cells the product is mRNA, which needs no post-transcriptional modification, while in eukaryotic cells, the first product is called primary transcript, that needs post-transcriptional modification (capping with 7 methyl guanosine, tailing with a poly A tail) to give hnRNA (heterophil nuclear RNA). hnRNA then undergoes splicing of introns (non coding parts of the gene) via spliceosomes to produce the final mRNA.


The synthesis of proteins is known as translation. Translation occurs in the cytoplasm where the ribosomes are located. Ribosomes are made of a small and large subunit which surrounds the mRNA. In translation, messenger RNA (mRNA) is decoded to produce a specific polypeptide according to the rules specified by the trinucleotide genetic code. This uses an mRNA sequence as a template to guide the synthesis of a chain of amino acids that form a protein. Translation proceeds in four phases: activation, initiation, elongation and termination (all describing the growth of the amino acid chain, or polypeptide that is the product of translation).

In activation, the correct amino acid (AA) is joined to the correct transfer RNA (tRNA). While this is not technically a step in translation, it is required for translation to proceed. The AA is joined by its carboxyl group to the 3' OH of the tRNA by an ester bond. When the tRNA has an amino acid linked to it, it is termed "charged". Initiation involves the small subunit of the ribosome binding to 5' end of mRNA with the help of initiation factors (IF), other proteins that assist the process. Elongation occurs when the next aminoacyl-tRNA (charged tRNA) in line binds to the ribosome along with GTP and an elongation factor. Termination of the polypeptide happens when the A site of the ribosome faces a stop codon (UAA, UAG, or UGA). When this happens, no tRNA can recognize it, but releasing factor can recognize nonsense codons and causes the release of the polypeptide chain. The capacity of disabling or inhibiting translation in protein biosynthesis is used by antibiotics such as: anisomycin, cycloheximide, chloramphenicol, tetracycline, streptomycin, erythromycin, puromycin etc.

Translation the process of converting the mRNA codon sequences into an amino acid polypeptide chain.

1.Initiation - A ribosome attaches to the mRNA and starts to code at the FMet codon (usually AUG, sometimes GUG or UUG).
2.Elongation - tRNA brings the corresponding amino acid (which has an anticodon that identifies the amino acid as the corresponding molecule to a codon) to each codon as the ribosome moves down the mRNA strand.
3.Termination - Reading of the final mRNA codon (aka the STOP codon), which ends the synthesis of the peptide chain and releases it.

Events following protein translation

The events following biosynthesis include post-translational modification and protein folding. During and after synthesis, polypeptide chains often fold to assume, so called, native secondary and tertiary structures. This is known as protein folding.

Many proteins undergo post-translational modification. This may include the formation of disulfide bridges or attachment of any of a number of biochemical functional groups, such as acetate, phosphate, various lipids and carbohydrates. Enzymes may also remove one or more amino acids from the leading (amino) end of the polypeptide chain, leaving a protein consisting of two polypeptide chains connected by disulfide bonds.

Thursday, August 27, 2009

Abnormal Digestion of food in the Small intestine--Pancreatic Failure

A serious cause of abnormal digestion is failure of the pancreas to secretes pancreatic juice into the small intestine.Lack of pancreatic secretion frequently occurs

(1)in pancreatitis

(2)when the pancreatic duct is blocked by a gallstone at the papilla of Vater

(3)after the head of pancreas has been removed because of malignancy.

Loss of pancreatic juice means loss of trypsin,chymotrypsin, carboxypolypeptidase, pancreatic amylase, pancreatic lipase, and still a few other digestive enzymes.Without these enzymes,as much as 60% of the fat entering the small intestine may be unabsorbed, as well as one third to one half of the proteins and carbohydrates.As a result, large portions of the ingested food cannot be used for nutrition, and copious fatty feces are excreted.
means inflammation of the pancreas, and this can occur in the form of either acute pancreatitis or chronic pancreatitis.
The most common cause of pancreatitis is drinking excess alcohol, and the second most common cause is blockage of the papilla of Vater by a gallstone; the two together account for more than 90% of all cases.When a gallstone blocks the papilla of Vater, this blocks the main secretory duct from the pancreas as well as common bile duct. The pancreatic enzymes are then dummed up in the ducts and acini of the pancreas. Eventually, so much trypsinogen accumulates that it overcomes the trypsin inhibitor in the secretion, and a small quantity of trypsinogen becomes activated to form trypsin. Once this happens, the trypsin activates still more trypsinogen as well as chymotrypsinogen and carboxypolypeptidase, resulting in a vicious circle until most of the proteolytic enzymes in the pancreatic ducts and acini become activated. These enzymes rapidly digest large portion of the pancreas itself, sometimes completely and permanently destroying the ability of the pancreas to secrete digestive enzymes.

Wednesday, August 26, 2009


Gingivitis ("inflammation of the gums") (gingiva) around the teeth is a general term for gingival diseases affecting the gingiva (gums). As generally used, the term gingivitis refers to gingival inflammation induced by bacterial biofilms (also called plaque) adherent to tooth surfaces.


The symptoms of gingivitis are as follows:[citation needed]

Swollen gums

Mouth sores
Bright-red, or purple gums
Shiny gums
Swollen gums that emit pus
Severe oral odor
Gums that are tender, or painful to the touch.
Gums that bleed easily, even with gentle brushing, and especially when flossing.
Gums that itch with varying degrees of severity.


Tuesday, August 25, 2009

Chronic pulmonary Emphysema.

-Excess air inside the lungs.
-Chronic infection.
-Chronic obstruction,due to excess mucus and inflammatory edema of bronchiolar epithelium.
-Difficult to expire,entrapment of air in the alveoli
and overstreching them
-Destruction of as much as 50% -80% Alveolar walls.
-Brochiolar obstruction increases airways resistance during expiration
-Loss of alveolar walls greatly decreases the diffusing capacity of the lungs to Oxygenate the blood and remove CO2 from the blood.
-Extremely abnormal ventilation--perfusion ratios.
-Loss of large portion of alveolar walls also decreases the number of pulmonary capillaries through which blood can pass as a result,the pulmonary vascular resistance often increases markedly, causing Pulmonary hypertension,this in turn overloads the right side of the heart and frequently causes right-sided Heart failure.

Chronic emphysema usually progress slowly over many years.

The person develops both Hypoxia and Hypercapnia because of Hypoventilation of many alveoli plus loss ofalveolar walls.the net result of all these effect is severe, prolonged devastating air hunger that can last for years until the hypoxia and hypercapnia cause death a high penalty to pay for smoking..



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Monday, August 24, 2009


Gastritis is not a single disease, but several different conditions that all have inflammation of the stomach lining. Gastritis can be caused by drinking too much alcohol, prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen, or infection with bacteria such as Helicobacter pylori (H. pylori). Sometimes gastritis develops after major surgery, traumatic injury, burns, or severe infections. Certain diseases, such as pernicious anemia, autoimmune disorders, and chronic bile reflux, can cause gastritis as well.

The most common symptoms are abdominal upset or pain. Other symptoms are belching, abdominal bloating, nausea, and vomiting or a feeling of fullness or of burning in the upper abdomen. Blood in your vomit or black stools may be a sign of bleeding in the stomach, which may indicate a serious problem requiring immediate medical attention.

Gastritis is diagnosed through one or more medical tests:

•Upper gastrointestinal endoscopy. The doctor eases an endoscope, a thin tube containing a tiny camera, through your mouth (or occasionally nose) and down into your stomach to look at the stomach lining. The doctor will check for inflammation and may remove a tiny sample of tissue for tests. This procedure to remove a tissue sample is called a biopsy.

•Blood test. The doctor may check your red blood cell count to see whether you have anemia, which means that you do not have enough red blood cells. Anemia can be caused by bleeding from the stomach.

•Stool test. This test checks for the presence of blood in your stool, a sign of bleeding. Stool test may also be used to detect the presence of H. pylori in the digestive tract.

Treatment usually involves taking drugs to reduce stomach acid and thereby help relieve symptoms and promote healing. (Stomach acid irritates the inflamed tissue in the stomach.) Avoidance of certain foods, beverages, or medicines may also be recommended.

If your gastritis is caused by an infection, that problem may be treated as well. For example, the doctor might prescribe antibiotics to clear up H. pylori infection. Once the underlying problem disappears, the gastritis usually does too. Talk to your doctor before stopping any medicine or starting any gastritis treatment on your own.

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Also called: Hemiplegia, Palsy, Paraplegia, Quadriplegia
Paralysis is the loss of muscle function in part of your body. It happens when something goes wrong with the way messages pass between your brain and muscles. Paralysis can be complete or partial. It can occur on one or both sides of your body. It can also occur in just one area, or it can be widespread. Paralysis of the lower half of your body, including both legs, is called paraplegia. Paralysis of the arms and legs is quadriplegia.

Most paralysis is due to strokes or injuries such as spinal cord injury or a broken neck. Other causes of paralysis include

Nerve diseases such as amyotrophic lateral sclerosis
Autoimmune diseases such as Guillain-Barre syndrome
Bell's palsy, which affects muscles in the face
Polio used to be a cause of paralysis, but polio no longer occurs in the U.S.

about Sleep paralysis

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Sunday, August 23, 2009


A hernia is a protrusion of a tissue, structure, or part of an organ through the muscle tissue or the membrane by which it is normally contained. The hernia has three parts: the orifice through which it herniates, the hernial sac, and its contents.


Hernias can be classified according to their anatomical location:
Examples include:
  • abdominal hernias
  • diaphragmatic hernias and hiatal hernias (for example, paraesophageal hernia of the stomach)
  • pelvic hernias, for example, obturator hernia
  • anal hernias
  • hernias of the nucleus pulposus of the intervertebral discs
  • intracranial hernias
  • Spigelian hernias [
Each of the above hernias may be characterised by several aspects:
  • congenital or acquired: congenital hernias occur prenatally or in the first year(s) of life, and are caused by a congenital defect, whereas acquired hernias develop later on in life. However, this may be on the basis of a locus minoris resistentiae (Lat. place of least resistance) that is congenital, but only becomes symptomatic later in life, when degeneration and increased stress (for example, increased abdominal pressure from coughing in COPD) provoke the hernia.
  • complete or incomplete: for example, the stomach may partially or completely herniate into the chest.
  • internal or external: external ones herniate to the outside world, whereas internal hernias protrude from their normal compartment to another (for example, mesenteric hernias).
  • intraparietal hernia: hernia that does not reach all the way to the subcutis, but only to the musculoaponeurotic layer. An example is a Spigelian hernia. Intraparietal hernias may produce less obvious bulging, and may be less easily detected on clinical examination.
  • bilateral: in this case, simultaneous repair may be considered, sometimes even with a giant prosthetic reinforcement.
  • irreducible (also known as incarcerated): the hernial contents cannot be returned to their normal site with simple manipulation.


It is generally advisable to repair hernias quickly in order to prevent complications such as organ dysfunction, gangrene, multiple organ dysfunction syndrome, and death. Most abdominal hernias can be surgically repaired, and recovery rarely requires long-term changes in lifestyle. Uncomplicated hernias are principally repaired by pushing back, or "reducing", the herniated tissue, and then mending the weakness in muscle tissue (an operation called herniorrhaphy). If complications have occurred, the surgeon will check the viability of the herniated organ, and resect it if necessary. Modern muscle reinforcement techniques involve synthetic materials (a mesh prosthesis) that avoid over-stretching of already weakened tissue (as in older, but still useful methods). The mesh is either placed over the defect (anterior repair) or more preferably under the defect (posterior repair). At times staples are used to keep the mesh in place. These mesh repair methods are often called "Tension Free" repairs because, unlike older traditional methods, muscle is not pulled together under tension. Evidence suggests that these Tension Free methods have the lowest percentage of recurrences and the fastest recovery period compared to older suture repair methods. Increasingly, some repairs are performed through laparoscopes.

US Navy surgeon performs a hernia repair surgery while at sea
Many patients are managed through day surgery centers, and are able to return to work within a week or two, while intensive activities are prohibited for a longer period. Patients who have their hernias repaired with mesh often recover in a number of days. Surgical complications have been estimated to be up to 10%, but most of them can be easily addressed. They include surgical site infections, nerve and blood vessel injuries, injury to nearby organs, and hernia recurrence.
Generally, the use of external devices to maintain reduction of the hernia without repairing the underlying defect (such as hernia trusses, trunks, belts, etc.), is not advised. Exceptions are uncomplicated incisional hernias that arise shortly after the operation (should only be operated after a few months), or inoperable patients.
It is essential that the hernia not be further irritated by carrying out strenuous labour.

Liver Functions and Liver diseases.

Liver functions:
it has a wide range of functions..
2.Glycogen storage
3.Decomposition of RBC's
4.Production of bile for fats digestion , absorption and emulsification of lipids.
5.Biochemical reactions.
6.Cholesterol formation.
7.Stores a multitude of
9.Produces Plasma proteins(albumins) and clotting factors and synthesizes angiotensiongen.
10.Breakdown of hemoglobin, creating metabolites that are added to bile as pigment (bilirubin and biliverdin).

Liver diseases:--------------------------

Liver disease (also called hepatic disease) is a broad term describing any single number of diseases affecting the liver. Many are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells; normally, the liver removes bilirubin from the blood and excretes it through bile.

(plural hepatitides) implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from ancient Greek hepar (ἧπαρ), the root being hepat- (ἡπατ-), meaning liver, and suffix -itis, meaning "inflammation" . ]. The condition can be self-limiting, healing on its own, or can progress to scarring of the liver. Hepatitis is acute when it lasts less than six months and chronic when it persists longer. A group of viruses known as the hepatitis viruses cause most cases of liver damage worldwide. Hepatitis can also be due to toxins (notably alcohol), other infections or from autoimmune process. It may run a subclinical course when the affected person may not feel ill. The patient becomes unwell and symptomatic when the disease impairs liver functions that include, among other things, removal of harmful substances, regulation of blood composition, and production of bile to help digestion.

Most cases of acute hepatitis are due to viral infections:

Other viral causes

Other viral infections can cause hepatitis (inflammation of the liver):

A large number of drugs can cause hepatitis:

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