Asthma

Around the world number of people suffer from asthma but its cause is incompletely understood. This condition in more common in developed countries with the highest number in New Zealand. Asthma is a chronic inflammatory condition in the lung airways. Main symptom is wheeze which may be associated with cough, chest tightness and shortness of breath. Asthma is very often aggravated at night.

Asthma is characterized by,

1. Air flow limitation
2. Airway hyper responsiveness
3. Inflammation of the bronchi

In chronic asthma airflow limitation can become irreversible.

Classification of asthma,

1. Extrinsic – There is a definite external cause
2. Intrinsic – Causative agent can not be identified

Factors which can aggravate asthma

Occupational sensitizers

• Isocyanades
• Complex salts of platinum
• Acid anhydrides

Cold air and exercise

Atmosphere pollution

Diet

Emotion

Drugs

E.g.: Non steroid anti inflammatory drugs

Beta blockers

Drug treatment

Inhalation of anti-inflammatory and bronchodilatory aerosols

B2-Adrenergic agonists

Anticholinergic bronchodilators

Anti-inflammatory drugs

Oral corticosteroids

Antibiotics

Cysteinyl leukotrien antagonists (LTRAs)

Mechanism of cell death in a myocardial infarction

In a myocardial infarction blood supply to a certain area of the heart muscle is cut off. Most often this happens due to an obstruction of a coronary artery.As the heart muscle cells are very active they have a high oxygen demand. Since o2 supply is cut off these cells enter a hypoxic state. Hypoxia affects oxidative phosphorylation in mitochondria and this causes the available ATP levels in the cell to decline. With the decrease of ATP, cellular AMP level increases. This increases AMP: ATP ratio and stimulates Phospho fructo kinase (PFK-1) enzyme. This enhances the rate of anaerobic glycolysis.

With the increased rate of anaerobic glycolysis,

1. Depletion of glycogen stores
2. Increase in intracellular lactic acid levels occur.

This increases intracellular acidity (decrease in pH)

Falling of the intracellular pH destabilizes the lysosomal membrane and causes hydrolytic enzymes in the lysosomes to come out. These enzymes hydrolyze intracellular biological molecules and ultimately lead to cell death. Ribosomes dissociate from RER and polysomes also dissociate.

In the other hand decreased ATP levels in the cell affect the function of Na+/K+ ATPase pump and causes Na+ to accumulate within the cell. This causes mitochondria, ER and the entire cell to swell. Blebs also appear on the cell surface.

Vegetative Propagation of Cinnamon

Rooting of semi-hard wood stem cuttings with single node is possible. The cuttings should be collected from the mother trees possessing desirable characteristics as indicated earlier. The trees should be in­duced to produce more shoots and when they are at early growth stages single nodal stem cuttings with full or half should be taken from the semi-hard woods and planted in polythene bags of 10cmx20crn filled with top soil. The bags are then covered with polythene sheet so as to prevent water losses due to evapotranspiration. Overhead shade is also necessary to prevent direct sunlight coming to the cuttings. Plants are ready for hardening in about 3-4 months and ready for field planting in about 10-20 months. Experimental work to improve this technique is underway.

DO YOU KNOW?

Snakes in Sri Lanka
There are 98 Snakes species found in Sri Lanka (Somaweera R. Check list of snakes in Sri Lanka as at January 2007). Among them 45 species are endemic to Sri Lanka. They are categorized in to 10 Families.

• ACROCORDIDAE
  
• BOIDAE
  
• COLUBRIDAE
  
• CYLINDROPHIIDAE
• ELAPIDAE
  
• HYDROPHIIDAE
  
• PYTHONIDAE
  
• TYPHLOPIDAE
  
• UROPELTIDAE
  
• VIPERIDAE
  

Snake venom

Even though there is vast number of snake species found in Sri Lanka, most of them are non venomous. So there is only few species of snakes which is medically imported. The snakes can
categorize in to 4 groups according to their venom.

Highly venomous snakes
Moderately venomous snakes
Mildly venomous snakes
Non venomous snakes

Highly Venomous Snakes

According to the venomous state there are 6 species of highly venomous snakes on Sri Lanka. But there are only 5 species which have ability to attack to humans. The coral snakes aren’t having ability to attack to humans.

1. Common Indian Krait
2. Sri Lankan Krait
3. Indian Cobra
4. Russell ’s Viper
5. Saw Scaled Viper
6. Sri Lankan Coral Snake

Common Indian Krait (Bungarus caeruleus)

Belongs to the family elapidae. Common Indian Krait is the most venomous snake on Sri Lanka. Widely spread through the dry zone. Nocturnal. Enlarged hexagonal vertebral scale makes easy to identify. The Wight rings on the body disappear with age. The rings are unpaired. Venom is a neurotoxin and cause neuromuscular paralysis.
Results a breathing difficulties, myalgia, changing sensorium, consciousness reduces, Brain death. Clinical signs and symptoms also includes abdominal pain, double vision, ptosis, autonomic failure, hypercalemiea.

Russell’s Viper (Daboia russelii)

Russell’s Viper (Daboia russelii)

Belongs to the family viperidae.Is responsible for the largest proportionate of deaths of Sri Lanka due to the snake bites. Has large head with relatively small neck. Have brownish gray, ovate spots along the vertebral region and white ‘V’ shaped mark on the head. Widespread in the dry zone, and the mid hills and plains up to 1500m of elevation. Has evolutionary more developed fang structure than elapids which improves the efficiency of the strike and injection of venom. The efficiency of the injection of venom is about (98%)The venom is both hematotoxic (80%) and nephrotoxic (18%). It is also has the properties of neurotoxin(78%). Hematosis, and clotting disorders occurs causing bleeding. Affects the neuromuscular transmission and cause muscle paralysis. If left untreated for long time, renal failure mayevelop. Hyperkaleamia (6.5%)

Saw Scaled Viper and Sri Lankan Coral Snake

Saw Scaled Viper (Echis carinatus)

Belongs to the family viperidae. Is relatively small snake which found in the north western, northern and north eastern arid coastal areas. Forehead with light grey cross and series of amber green patches along the vertebral areas helps to identify. Only few cases were reported from Jaffna, mannar and yala. The venom is hematotoxic and nephrotoxix. Vomiting of blood and bleeding from the gums.

Sri Lankan Coral Snake (Calliophis melanurus)

Belongs to the family elapidae. There are 2 species of coral snakes in Sri Lanka. One specie and One Sub Specie is endemic to SL. Commonly found in dry zone. These species are highly venomous but small in size, so their fangs aren’t able to pierce the skin of large animals. So bites aren’t recorded from these species.