Monday, September 30, 2013

Risk factor for early childhood death

Young mothers 'risk factor for early childhood death'

Children born to mothers under 30 are more likely to die than those born to older mums, a report on child deaths in the UK suggests.


While overall child mortality fell by 50% in the past 20 years, young maternal age was found to be a risk factor for death in early childhood.



Support should be extended to mothers of all ages, not just first-time teenage mums, the report said.


Thursday, September 26, 2013

Promising results on Type 1 diabetes : Skin drugs

Skin drug shows 'promising' results on type 1 diabetes

A drug that was used to treat a skin disorder has shown signs of being able to treat aspects of type 1 diabetes. A small trial on US patients suggests that alefacept helps the body produce its own insulin, which is key for people with type 1 diabetes. Type 1 diabetes affects around 400,000 people in the UK.

Researchers said the drug could be better than other treatments because it protects the immune system - but more research was needed.

Universal flu vaccine : Great steps of scientific discovery

Scientists take big step towards universal flu vaccine

Scientists say they have made a significant leap towards creating a vaccine that would protect against every form of flu. The influenza virus is a constantly shifting target so seasonal flu vaccines rapidly become useless and new ones are needed each year.

A team at Imperial College London say they have made a "blueprint" for a universal flu vaccine. Their discovery is published in the journal Nature Medicine. Influenza is able to change the proteins that protrude from the surface of the virus as readily as people change outfits. However, the material on the inside is common

Type 2 Diabetes and Anti-depressants

Anti-depressants 'linked to type 2 diabetes'

People prescribed anti-depressants should be aware they could be at increased risk of type 2 diabetes, say UK researchers.
The University of Southampton team looked at available medical studies and found evidence the two were linked.
But there was no proof that one necessarily caused the other.
It may be that people taking anti-depressants put on weight which, in turn, increases their diabetes risk, the team told Diabetes Care journal.
Or the drugs themselves may interfere with blood sugar control.

Wednesday, September 25, 2013

RBC Metabolism Notes (Part 5) : Role of Vitamin B12 and Pernicious anemia

COBALAMIN (Vitamin B12)

  • Vitamin B12 is required in humans for two essential enzymatic reactions: the synthesis of methionine and the isomerization of methylmalonyl CoA that arises from the fatty acids with odd numbers of carbon atoms (Fig 28.10).
  • When the vitamin is deficient, abnormal fatty acids accumulate and become incorporated into cell membranes, including those of the nervous system. 

RBC Metabolism Notes (Part 4) : Maturation of RBC and role of Folic acid

MATURATION OF RBC - ROLE OF FOLIC ACID & VITAMIN B12 IN DNA SYNTHESIS

 

FOLIC ACID

  • Folic acid (or folate) plays a key role in one-carbon metabolism, and is essential for the biosynthesis of the purines and the pyrimidine, thymine. 
     
  • Folic acid deficiency is probably the most common vitamin deficiency in the U.S., particularly among pregnant women and alcoholics.

Structure of Folic Acid

  • Folic acid is composed of a pterin ring attached to p-aminobenzoic acid (PABA) and conjugated with one or more glutamic acid residues.

RBC Metabolism Notes (Part 3) : Energy metabolism


ENERGY METABOLISM
  • Although the mature red cell contains the enzymes required for glycogen metabolism, the balance between synthesis and utilization is such that no significant amount of glycogen accumulates within the cell under normal circumstances. 

  • Glycogen may accumulate, however, in glycogen storage diseases types III and VI.

RBC Metabolism (Part 2) : Mechanisms of preventing oxidative denaturation of hemoglobin

  • Fig. Enzyme that converts MetHb to Hb
    Known mechanisms of preventing or reversing oxidative denaturation of hemoglobin in the erythrocyte include 
    • the methemoglobin reductases
    • superoxide dismutase
    • glutathione peroxidase
    • catalase.
(Fig. in left NADH_cytochrome_B5_reductase)
Methemoglobin Reduction
  • Most methemoglobin in the erythrocyte is reduced through the action of an enzyme cytochrome b5 methemoglobin reductase, which acts in the presence of two electrons carriers, cytochrome b5, and NADH.

Tuesday, September 24, 2013

RBC Metabolism Notes (Part 1) : Stages of oxidative denaturation of Hemoglobin

OXIDATIVE DENATURATION OF HEMOGLOBIN: IT’S REVERSIBILITY AND PREVENTION

INTRODUCTION

  • Oxyhemoglobin in solution gradually undergoes autoxidation, becoming methemoglobin (HbFe+++).
  • The rate of oxidation is enhanced by conditions such as increased temperature, decreased pH and presence of organic phosphate and of metal ions, and partial oxygenation of hemoglobin. To bind oxygen reversibly, however, the iron in the heme moiety must be maintained in the reduced (ferrous Fe++) state, despite exposure to a variety of

Monday, September 16, 2013

Neurotransmitter : Overview and Functions

What are Neurotransmitters?  How do they affect your life?
Just like hormones govern many chemical functions in the body, the brain's chemical functions are governed by messengers called neurotransmitters.

Fig. Neurosynaptic transmission
A neurotransmitter is a chemical messenger used by neurons (nerve cells) to communicate in one direction with other neurons. These neurotransmitters are either excitatory or inhibitory. Each cell receives its instructions through nerve processes called dendrites and it passes on instructions to the next cell through its axon. The gap between the axon of one cell and the dendrite of the next is called a synapse.

Special molecules in the dendrite are called receptors. They are shaped to receive only one type of neurotransmitter, which fits it like a key in a lock. The result is that if an excitatory

Thursday, September 12, 2013

Alternative to nicotine patches: E-cigarette

E-cigarettes 'as effective' as nicotine patches

Electronic cigarettes appear to be at least as effective as nicotine patches in helping people to give up smoking, research suggests.
Fig. E-cigarette (Courtesy: ecigaretteuser.com)
The devices, which are rapidly growing in popularity, produce a vapour containing nicotine.
The findings, presented at the European Respiratory Society, showed similar numbers quitting with e-cigarettes as patches, but more had cut down.
There was a call, however, for long-term data on safety.

Testicle size 'link to father role'

A link between the size of a father's testicles and how active he is in bringing up his children has been suggested by scientists.
Researchers at Emory University, US, said those with smaller testicles were more likely to be involved with nappy changing, feeding and bath time.
They also found differences in brain scans of fathers looking at images of their child, linked to testicle size.
But other factors, such as cultural expectations, also played a role.
Levels of promiscuity and testicle size are strongly linked in animals, those with the largest pair tending to mate with more partners.

The researchers were investigating an evolutionary theory about trade-offs between investing time and effort in mating or putting

Tuesday, September 10, 2013

Cancer gene testing : BRCA1 and BRCA2 genes

Explaining Jolie's cancer:

News of Angelina Jolie's decision to undergo a prophylactic double mastectomy has instantly increased awareness of hereditary forms of cancer caused by mutations in the BRCA1 and BRCA2 genes.

Fig. Actress Angelina Jolie
While the BRCA1 and BRCA2 genes were discovered in the mid-1990s, genetic testing for the genes is increasingly available. Jolie's case highlights the importance of knowing one's family history and learning one's cancer risks in order to address them proactively.

Everyone has the BRCA1 and BRCA2 genes. We have two copies of each gene and get one each from our mother and father. They play a role in protecting the body against the development of cancer.

Individuals with mutations in either of these genes have increased cancer risks, most notably for breast and ovarian cancer. Individuals with mutations in BRCA1 and BRCA2 benefit from tailored management aimed at reducing cancer risks and detecting cancers early when they are most treatable.

Friday, September 6, 2013

Interpreting and Correlating Abnormal Laboratory Values : Cardiac Function Tests

Diagnosis of Myocardial Infarction (MI) and Acute Coronary Syndrome

Fig. Getting MI attack
Since acute MI (AMI) requires rapid and accurate diagnosis, especially now that new treatment options with thrombolytic agents are available, the clinical laboratory has been called upon to provide serum diagnostic tests that can make this diagnosis at an early stage. Until recently, laboratory diagnosis was based on serial determinations of the MB fraction of creatine phosphokinase (CK-MB); confirmation of the diagnosis was provided by the so-called ‘flipped ratio’ of the isozymes of lactate dehydrogenase (LD) 24-36 hours after the initial acute event and/or by observation of the characteristic time courses for elevations of the three enzymes, CK, aspartate aminotransferase (AST) and LD.

Interpreting and Correlating Abnormal Laboratory Values : Liver Function Tests

The most common liver test abnormalities can be summarized to a set of six conditions as in Table 1. The principles for these patterns are explained as follows.
  
1.   
All acute injuries and/or necrotic lesions in the liver primarily cause a marked rise in the levels of the aminotransferases, aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Cell injury and necrosis also cause the rise of other enzymes such as lactate dehydrogenase (LD). These include acute hepatitis

Thursday, September 5, 2013

Interpreting and Correlating Abnormal Laboratory Values : Electrolyte Abnormalities


Electrolyte Abnormalities
Hyponatremia

The four most common causes of hyponatremia are given in Table 1 (See below), together with a fifth, rare, cause, Bartter's syndrome. A sixth, metabolic cause, diabetes mellitus, is also presented in this table. In all forms of hyponatremia, the chloride ion concentration is also generally low since chloride is the chief counter-ion for sodium.

Interpreting and Correlating Abnormal Laboratory Values : Glucose Abnormalities

The major purpose of performing analyte determinations in the clinical laboratory is to aid in the diagnosis and management of patients with disease and individuals in health assessment. In this regard, the clinical pathologist/Clinical Biochemist/Clinical Microbiologist are often called upon as a consultant to explain abnormal laboratory values, especially those that do not seem to correlate with one another, and to recommend or even to order laboratory tests that may lead to the correct diagnosis in the work-up of patients for particular medical problems.

POCT : Point of Care testing - Introduction, Utility and Management

Point-of-care testing (POCT) is an emerging concept in laboratory medicine and has attracted considerable interest in the medical literature. Recent experience has revealed a variety of applications for these new technologies in
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