1. Where do most allergic reactions occur?
Most of them occur on mucous membrane. Allergens enter the body by the process of inhalation or ingestion.
2. Who are atopic individuals?
Atopic individuals are those who are having abnormal high levels of circulating IgE and more than normal number of oesinophils.
The tendency to manifest localized anaphylactic reactions is called atopy.
4. Name some common allergens associated with type-I hypersensitivity?
Penicillin, sulfonamide, eggs, milk, dust mites, animal air, vaccines etc.
Allergens are non-parasitic antigens. They are capable of stimulating hypersensitive reactions in allergy conditions in an individual.
6. Which type of immunoglobulin level will increase when an individual is exposed to a parasite?
Serum IgE levels will increase and remain until the parasite is washed out from the body.
7. Do you know how the dose for children is being estimated based on preclinical data?
There are a number of ways of estimating children's doses from preclinical (adult) data - often depends on the therapeutic index of the drug in question (the wider the therapeutic window the less accurate the child's dose needs to be). Sometimes straight weight-basis i.e. 7kg child gets 1/10 dose of 70kg adult.
More accurate (so they say) is a dose based on body surface area (child's surface area is greater in proportion to its body weight than an adult is). There are normograms to calculate surface area from weight and height of child.
All of these may be wrong if clearance of drug in child is significantly different from adult e.g. different metabolism or different route of clearance.
8. What is the definition of “Biomedical”? What topics cover the Study of Biomedical Sciences?
The term "biomedical" covers a vast range of subjects - everything that relates biology to medicine. This can range from the obvious like Anatomy, Biochemistry, Physiology, Microbiology, Pharmacology, Genetics to the less obvious like Botany (most drugs were originally derived from plants and, thus, these is a big science called Phytopharmacology).
Phenoxyethanol is harmful and can be absorbed through the skin - official sites for toxicity data, however, show little toxicity in man and some toxicity (irritation) with high doses in animals. Phenoxyethanol is in cosmetics as a bactericide (kills bacteria).
Buprenorphine is what is referred to as a partial agonist - i.e. it binds to the receptor but even at its maximum cannot give as much of an effect as a full agonist (such as morphine) - it is, thus, also a partial antagonist (partially inhibits the actions of full agonists).
As addiction is likely to be linked to strength of the effect of the drug, buprenorphine has less effect and, therefore, less addiction.
11. How is the concentration of drugs in human plasma defined?
Some drugs bind extensively to plasma proteins (Warfarin binds 99%) whereas others have virtually no binding.
Extraction depends on the type of drug - there are different standard techniques for acidic, basic, and neutral drugs - and, indeed, some drugs need specific extraction techniques.
It is important for you doing bioequivalence studies to know exactly the proportion of drug extracted but such controls are again specific for each drug and use specific marker compounds.
To be "bioequivalent" two preparations or drugs need to give the same biological effect.
The usual "experimental error" put on this is 20% - thus, 80-120% is considered "bioequivalent.”
90 percentage confidence interval means that statistically it is 90% certain that the results are equivalent.
The idea of adding acid/base is to change the lipid (and therefore organic solvent) solubility of the components you want to extract.
For example, a fatty acid is more soluble in water as a salt (and, thus, in basic conditions) whereas it is largely insoluble in water in its uncharged state (in acid conditions). So adding acid to the solution of fatty acid salt in water will render it water-insoluble and, thus, move it from the water to the organic solvent.
This is a standard extraction technique for organic acids and bases. Also, note that exact concentrations of acid/base need to be calibrated for each extraction.
Gel formation is difficult to deal with, as you cannot be sure of the extraction (difficult to mix and separate). We would suggest changing the method unless you can show a decent extraction or the description of the method says to expect a gel formation.
Sodium hydroxide is a very caustic substance - severe burns on skin contact, can cause severe eye irritation and burning - can severely damage surface of eye causing blindness (permanent), severe burring on ingestion and inhalation.
Butane is a gas - it is very toxic if inhaled - acts like an anesthetic - can stop person breathing very quickly.
Diethyleneglycol monobutyl ether is less acutely toxic but does have long-term toxicity on various organs.
15. Tell us about some drugs that can cross the blood brain barrier?
Any drug that is designed to be given orally, i.m. s.c. or i.v. and acts on the brain MUST cross the blood-brain barrier.
E.g. Opiates, anxiolytics, SSRI's, anti-psychotics
Drug needs to be lipid (fat) soluble to cross the BBB.
16. Give an example for electrophilic substitution reaction?
The species, which accepts the electrons, are called Electrophilles (or) Electrophilic reagents. When the atom (or) group of atoms present in the organic compound is replaced by another atom (or) group of atoms (electrophilic) is called electrophilic substitution reaction.
Clarithromycin is chemically related to erythromycin and almost certainly is cross-reactive - so if you are allergic to erythromycin you will most likely be allergic to clarithromycin as well.
The response produced when an allergen is injected into an individual, who is sensitive is called P-K reaction.
19. What are high affinity receptors?
Mast cells and basophils express high affinity receptor. The high affinity enables it to bind with IgE, despite low serum concentration of IgE.
20. What are low affinity receptors?
Low affinity receptors play role in regulating he intensity of IgE response.
21. What are primary mediators?
Primary mediators are those, which are produced before degranulation. These primary mediators are stored in granules. Some of the primary mediators are histamine, heparin, proteases etc.
22. What are secondary mediators?
Secondary mediators are produced after target cell activation or released by the break down of phospholipids membrane during the process of degarnulation. Some of the secondary mediators are leukotrienes, various cytokines, prostaglandins etc.
23. Explain in brief about histamine?
It is formed by the decarboxylation of amino acid histidine. It accounts for 10% of granule weight. This histamine binds to specific receptors on various target cells.
24. How many types of histamine receptors are there and what are they?
There are three types of histamine receptors. They are H1, H2 and H3.They has different tissue distributions.
25. What is the reaction-taking place when H2 receptor binds to mast cells and basophils?
When H2 binds to mast cells and basophils it suppresses degranulation.
