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Tuesday, June 3, 2014

Competitive, uncompetitive and non competitive enzyme inhibitors

(A) Enzyme–substrate complex; 
(B) a competitive inhibitor binds at the active site and thus prevents the substrate from binding; 
(C) an uncompetitive inhibitor binds only to the enzyme–substrate complex; 
(D) a noncompetitive inhibitor does not prevent the substrate from binding.

Visceral and parietal layer of serous pericardium

The pericardium is a fibroserous sac surrounding the heart and the roots of the great vessels. It consists of two components, 
1) the fibrous pericardium and 
2) the serous pericardium.

The fibrous pericardium is a tough connective tissue outer layer that defines the boundaries of the middle mediastinum. 

The serous pericardium is thin and consists of two parts:
1) The parietal layer lines the inner surface of the fibrous.
2) The visceral layer adheres to the heart and forms its outer covering.

The parietal and visceral layers of serous pericardium are continuous at the roots of the great vessels. The narrow space created between the two layers of serous pericardium, containing a small amount of fluid, is the pericardial cavity. This is pictured in the diagram above as a fist in a filled balloon. This potential space allows for the relatively uninhibited movement of the heart.

Fibrous pericardium
The fibrous pericardium is a cone-shaped bag with its base attached to the central tendon of the diaphragm
and a small muscular area on the left side of the diaphragm and its apex continuous with the adventitia of the great vessels. Anteriorly, it is attached to the posterior surface of the sternum by sternopericardial ligaments. 
These attachments help to retain the heart in its position in the thoracic cavity. The sac also limits cardiac 

Serous pericardium
The parietal layer of serous pericardium is continuous with the visceral layers of serous pericardium around the roots of the great vessels. These reflections of serous pericardium occur in two locations:
1) one superiorly, surrounding the arteries, the aorta and pulmonary trunk;
2) the second more posteriorly, surrounding the veins, the superior and inferior vena cava and the pulmonary veins.

Saturday, April 26, 2014

Diaxozide - mechanism of action

The diagram shows a beta cell of the islet of pancreas and will explain how local factors regulate secretion of insulin from it.
Glucose enters the cell via the GLUT-2 transporter. Inside the cell there is metabolism with the generation of ATP. This causes the ATP-sensitive K+ channel to close, as shown in A.
Closure of this channel leads to cell membrane depolarization. This in turn allows calcium ions to enter the cell via another calcium channel, shown in B. Increased intracellular calcium activates calcium dependent phospholipid protein kinase. This leads to exocytosis of insulin granules.

Diaxozide acts by opening the K+ channel. This leads to loss of K+ and causing membrane hyperpolarization. This prevents Ca2+ from entering, protein kinases are not activated and thus there is no exocytosis of insulin granules... 

Sunday, December 15, 2013

Prognostic scores in alcoholic hepatitis

1. Maddrey (modified) Discriminant Function score of greater or equal to 32 indicates a high risk (30-50%) risk of mortality at 30 days. The risk is even higher is there are signs of hepatic encephalopathy. Scores should be repeated at day 7.

2. MELD stands for Model for End stage Liver Disease. It is used to estimate 90 days mortality. Poor prognosis if score is greater than 18. Score should be repeated at day 7.

Sunday, October 6, 2013

Effect of weather on COPD

Exacerbations of COPD are more commonly seen during the winter season (nearly 1.6 times more frequently). The main cause of these exacerbations is infection with the respiratory virus, rhinovirus.
Frequent exacerbations have been shown to lead to a faster decline in the lung function, poorer quality of life and increased mortality.
A recent study showed that COPD exacerbations in colder periods of the year take longer to recover from and are more likely to involve cough or coryzal symptoms. The exacerbations in the cold seasons also have a greater impact on daily activity, with patients spending more time indoors and being more likely to be hospitalized with respiratory viral infection.

Monday, August 5, 2013

X ray spina bifida occulta

It is the case of a 16-yr old female who came to the emergency department with complaints of low back ache for the past week. She has had similar symptoms in the past but now the intensity is increasing.
There is no associated numbness or weakness of extremities. She did not have any weight loss. There was neither urinary nor fecal incontinence.

On examination she had an obvious limp.
Lumbar spines: mild tenderness lower lumbar spines, no deformity, range of motion was normal, no stigma of spina bifida.
Lower limbs length showed a discrepancy of 1.5cm being shorter by 1.5cm on the left side.
Left ankle in inversion and with hyperlaxity while left ankle was stiff and with restricted inversion.

X-ray of Lumbar Spines showed a spina bifida.

Impression of Spina Bifida occulta was made.

Sunday, June 2, 2013

Diabetes - 7 keys messages to the patients

1. Diabetes is self-managed.

Caring for diabetes is more than just taking a daily pill or doing your insulin injection. It may feel like a burden but the decisions you make about physical activity, what and when you will eat will affect both how you feel today and your future health and well-being.

2. Take diabetes seriously.

It is a multi-systemic disorder and indeed needs a lot of care. Since the symptoms and complications take time to appear you may think that it is a simple disease but it is not in reality!!!

3. Learn everything about the disease.

Since most of diabetes care is  about self-care, the more you know about it, the better you will be able to manage it. You can control your diabetes rather than letting your diabetes control you. If possible, try to get updated with latest developments in the field and read to drive away myths about the disease.

4. Your treatment will change over time.

Treatment of diabetes will eventually change over time. Changes in treatment do not mean that you have failed or that your diabetes is worse. It simply means that your body needs more help to keep your blood glucose level on target. Insulin therapy is part of the treatment and not a punishment.

5. Negative emotions are common.

It can be difficult to live with diabetes and researchers have shown that patients are about twice as likely to become depressed. Let your doctor know if your emotions are getting in the way of managing diabetes or enjoying your daily life. Do not hesitate to go for a psychological evaluation.

6. Step by step is the motto.

Diabetes often involves making changes in your food, exercise and other habits. It can quickly become too hard if you try to do it all at once. Start by choosing one thing that is important to you. Try to make small changes each day. It is likely that you will try different things along the way. Use what you learn about what does and does not work as a guide. Perfection is not the goal. It is what you do most of the time that counts.

7. Complications don't always happen.

You may have seen the toll of long-term complications on others. The good news is that these can be delayed or prevented by keeping your blood glucose and blood pressure levels in the target ranges. There are no guarantees, but you can greatly reduce your risk.

Living with diabetes is not easy. But with the help of your health care team and your family and friends, you can do it.

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