Wednesday 31 October 2012

Research on buah Melaka

The buah Melaka fruit is famous not only for naming Malacca (Melaka) but also for its present research on cancer, pancreatitis and hypercholesterolaemia.


Indian gooseberry has undergone preliminary research, demonstrating in vitro antiviral and antimicrobial properties. There is preliminary evidence in vitro that its extracts induce apoptosis and modify gene expression in osteoclasts involved in rheumatoid arthritis and osteoporosis. It may prove to have potential activity against some cancers. One recent animal study found treatment with E. officinalis reduced severity of acute pancreatitis (induced by L-arginine in rats). It also promoted the spontaneous repair and regeneration process of the pancreas occurring after an acute attack.
Experimental preparations of leaves, bark or fruit have shown potential efficacy against laboratory models of disease, such as for inflammation, cancer, age-related renal disease, and diabetes.
A human pilot study demonstrated a reduction of blood cholesterol levels in both normal and hypercholesterolemic men with treatment. Another recent study with alloxan-induced diabetic rats given an aqueous amla fruit extract has shown significant decrease of the blood glucose, as well as triglyceridemic levels and an improvement of the liver function caused by a normalization of the liver-specific enzyme alanine transaminase activity. Wikipedia http://en.wikipedia.org/wiki/Phyllanthus_emblica

ALT = alanine transaminase

Tuesday 23 October 2012

Glucose/Alanine Cycle

What is the glucose/alanine cycle? How is it important to metabolism?

Related topics:
  1. ENERGY SUPPLY DURING FASTING
  2. GLUCONEOGENESIS 
  3. PROTEINS & AMINO ACIDS AS ENERGY SOURCE 
Keywords: skeletal muscle; breakdown of muscle to supply energy during fasting; use of amino acids as a source of energy; alanine; ALA.


GLUCOSE/ALANINE CYCLE

(i) Summary of the glucose/alanine cycle:
  1. During extended periods of fasting (eg baby not feeding well, Ramadan fasting/puasa bulan Ramadhan), skeletal muscle is degraded as an alternative source of energy.
  2. Alanine is the major amino acid present when muscle (protein) is degraded.
  3. The glucose-alanine cycle occurs in skeletal muscle to eliminate nitrogen while replenishing (renewing) the energy supply for muscle.
  4. The amino group transported from the muscle to the liver in the form of alanine, is converted to urea in the urea cycle and excreted.

(ii) Reactions in skeletal muscle:
  1. In muscle cells and other peripheral tissues, glycolysis produces pyruvate.
  2. Pyruvate can be transaminated to  alanine.
  3. The transamination reaction requires an α-amino acid as donor of the amino group, generating an α-keto acid in the process. 
  4. This reaction is catalyzed by alanine transaminase, ALT.
  5. The alanine then enters the blood stream and is transported to the liver.
  6. Alanine is returned to the liver for gluconeogenesis.

(iii) Reactions in liver:
  1. Within the liver, alanine is converted back to pyruvate by deamination.
  2. Pyruvate is a source of carbon atoms for gluconeogenesis.
  3. Gluconeogenesis converts pyruvate to form glucose.
  4. The newly formed glucose can then enter the blood for delivery back to the muscle.
  5. This pathway is termed the glucose-alanine cycle.

(iv) Related FAQs and comments:
  1. Note: Liver is a hepatic tissue. Muscle is a non hepatic tissue or extrahepatic tissue, EHT.
  2. Note: Skeletal muscle is protein.
  3. Alanine is the major amino acid in protein (eg skeletal muscle). 
  4. Transamination. The amino group is transferred to another molecule. What does transamination mean? Write down this reaction. What are the subsrates, products and enzyme?
  5. Note: Urea cycle occurs in the liver.  What is the structure of urea?
  6. What is the urea cycle? What is its importance?
  7. What happens if the urea cycle does not function?
  8. What is the condition when there is high urea present in blood?
  9. What happens when there is ammonia build-up in the body?
  10. What is the condition when there is high ammonia present in blood?
  11. Is ALT an important enzyme? What does the presence of high ALT in serum indicate?
  12. Please take note: ALT used to be referred to a serum glutamate-pyruvate transaminase, SGPT, as serum was used for the determination on the enzyme. The term SGPT is now obsolete and you will only see it in old textbooks.

(v) Images of the glucose/alanine cycle:

Eglobalmed.com:




The Medical Biochemistry Page.Org:
http://themedicalbiochemistrypage.org/gluconeogenesis.php



Andrea Hambly's White Tiger Natural Medicine:
http://www.whitetigernaturalmedicine.com/nutrition/proteins-amino-acids

PowerPoints

http://slideplayer.com/search/alanine+cycle/

http://slideplayer.com/slide/4214240/

http://slideplayer.com/slide/4213836/

Monday 22 October 2012

Electron Transport Chain (ETC)

There are many diagrams depicting the electron transport chain (ETC). However, students should not confuse the ETC with the thyllakoid membranes in leaves of plants, which are involved in photosynthesis. Look for the right diagrams. Examples of the ETC are available on the Internet.

Springer Images:
http://www.springerimages.com/Images/LifeSciences/5-10.1186_1471-2164-11-203-2















WordPress:
http://giantshoulders.files.wordpress.com/2007/10/etccomplexes.jpg


Other images of the ETC can be searched at Google:
Type "electron transport chain images".

PowerPoints

http://slideplayer.com/search/electron+transport+chain/

http://slideplayer.com/slide/4088596/#

http://slideplayer.com/slide/4052610/

Animations

http://tube.medchrome.com/2012/04/electron-transport-chain-and-oxidative.html

Cori Cycle

What is the Cori cycle? How is it important to metabolism?

  1. The Cori cycle is also known as the lactic acid cycle.
  2. The Cori cycle involves 2 organs, the contracting muscle and the liver.
  3. It functions in anaerobic conditions when the muscles are contracting under reduced oxygen.
  4. The contracting muscles produce lactate (instead of pyruvate proceeding to acetyl CoA to TCA cycle) which is supplied to the liver.
  5. In the liver, gluconeogenesis converts lactate to pyruvate and glucose.
  6. Glucose is then metabolised by contracting muscle via glycolysis, to pyruvate and acetyl CoA under aerobic condition (sufficient oxygen), and acetyl CoA enters TCA cycle. Otherwise the glucose goes through anaerobic glycolysis and the Cori cycle goes on till oxygen is sufficient.






Click on Cori cycle label below to see other posts on Cori cycle.

PowerPoints

http://slideplayer.com/search/cori+cycle/1/

http://slideplayer.com/slide/4450545/

http://slideplayer.com/slide/3863013/

Sunday 21 October 2012

Friday 12 October 2012

Snake venoms

In the SGD on ENZYMOLOGY, BIOENERGETICS & BIOMOLECULES on 8 & 9 October 2012, I covered Snake Venoms for my groups, Groups 2A & 2B. Students in the other groups may not be aware of what I had covered. So I will share about Snake Venoms here. You can read up on Snake Venoms on your own.

In 1834, Charles Lucien Bonaparte, (nephew of Napoleon Bonaparte) discovered that snake venoms were proteinaceous. Snake venoms are important to Biochemistry and come under Enzymology. Snake venoms contain a host of 20 chemicals, including proteins and peptides, most are enzymes. Some of the most dangerous and powerful enzymes are in snake venoms. There are many types of enzymes in snake venoms, mainly hydrolytic and digestive enzymes, which damage the vascular endothelium.

There are four distinct types of venom that act on the body differently:
  1. Proteolytic venom dismantles the molecular structure of the area surrounding and including the bite. 
  2. Hemotoxic venoms act on the heart and cardiovascular system. 
  3. Neurotoxic venom acts on the nervous system and brain. 
  4. Cytotoxic venom has a localized action at the site of the bite.
Enzyme activities in snake venoms can be inhibited if acted upon immediately after a snakebite. Snake venom contains active enzymes. Enzyme activity is controlled by pH. Changing the pH of the medium will stop enzyme activity. Immediately applying alkaline solution (lye water, ash water, bicarbonate, etc) will halt enzyme activity in snake venoms/at the bite site.

Snake Venom
http://en.wikipedia.org/wiki/Snake_venom

Charles Lucien Bonaparte and Mourning Dove
http://tailsofbirding.blogspot.com/2011_08_01_archive.html

Do'a Ruqyah: Pengubatan gigitan dan sengatan binatang berbisa
  1. Bacakan Surah al-Faatihah. Kemudian tiupkan ke tempat yang tersengat. Gosokkan bersama air liur orang yang membacanya.
  2. Gosokkan dengan air dan garam sambil dibacakan Surah al-Kaafirun, Surah al-Falaq, dan Surah an-Nas.

Lung surfactant

During STRUCTURE AND FUNCTION OF LIPIDS lecture to Year 1 Medicine, I forgot about Phospholipids structure and function, and did not cover its significance. So students will need to read up on their own. I have provided a brief guide below to help you with your reading.

If you remember, I talked about surface tension of water in my lecture. I showed the glass tubes with the 2 different water curvature at the water-air interface. The application of that is when we talk about phospholipids. Phospholipids have 2 main functions in our bodies. One function is for making lipid bilayer membrane. The second function is as lung surfactant - to reduce the surface tension of water-air interface in the lung alveoli, so breathing can occur (inhale and exhale, without the alveoli collapsing). However, some newborns lack the pulmonary surfactant, and thus suffer from respiratory distress syndrome (RDS).

RDS is a medical emergency. RDS is a breathing disorder that affects newborns. RDS rarely occurs in full-term infants. The disorder is more common in premature infants born about 6 weeks or more before their due dates. RDS is a common lung disorder in premature infants. In fact, nearly all infants born before 28 weeks of pregnancy develop RDS. They may survive for a few days but often succumb within a week. 

Sometimes big babies born at term also experienced RDS. Since they are big babies, they experienced difficulties during delivery, often due to shoulder dystocia (sukar nak keluar bahu bayi). The baby struggles and in the end makes it but had swallowed some of the amniotic fluid and bacteria during the ordeal and suffers from RDS. So it is worth avoiding having big babies.

Interesting reads in medical history are:
  1. Discovery of lung surfactant by Kurt von Neergaard in 1929
  2. Discovery of the detailed mechanism of how pulmonary surfactant functions in 1950s
  3. Death of Jacqueline Kennedy's newborn son in 1963 despite best efforts
  4. Reduced deaths of newborns when RDS was treatable
  5. Manufacture of lung surfactants - artificial and natural  (from cows and pigs)
From the laboratory aspect, it is possible to detect whether the lungs have fully developed and whether newborns will be able to use their lungs. The test done is called L/S ratio. L stands for lecithin and S stands for sphingomyelin. The L/S ratio is the ratio of lecithin to sphingomyelin. It tells us whether the lungs are mature or not, will function alright or otherwise, whether the baby is ready to breathe on its own or not, etc. The L/S ratio was much depended upon in the past.

Pulmonary surfactant
http://en.wikipedia.org/wiki/Pulmonary_surfactant

Respiratory Distress Syndrome (RDS)
http://www.thoracic.org/education/breathing-in-america/resources/chapter-19-respiratory-distress-syndr.pdf

National Heart Lung and Blood Institute (NHLBI)
http://www.nhlbi.nih.gov/health/health-topics/topics/rds/

American Lung Association
http://www.lung.org/#