Erythropoiesis: It denotes the formation of red blood cells.
Monday, March 14, 2011
Cystine
Cystine: It is an amino acid that is crystalline in nature and is a part of many proteins such as that of keratin.
Condensation
Condensation: It is the process of the formation of molecules which are denser than their parent compounds. It is done usually with the escape of simple substances such as water.
Bone marrow
Bone marrow: A soft type of substance present inside some of the bones that is involved in the generation of blood cells. It is also called as “medulla osium”.
Hydroxyurea
It is used to treat sickle cell disease.
Mechanism of action:
It is found to promote the level of fetal hemoglobin resulting in the dilution of abnormal hemoglobin S (HbS). This may take a long time of up to many months. As a result slow polymerization of HbS occurs and painful conditions are not developed by the sickle cells which are blocking capillaries and causing inadequate supply of oxygen in tissues.
Therapeutic uses:
It is helpful in relieving pain of patients with sickle cell disease.
It is also used to cure chronic type of myelogenous leukemia and polycythemia vera.
Adverse effects:
It may cause suppression of bone marrow and inflammation of the vessels of the skin.
Mechanism of action:
It is found to promote the level of fetal hemoglobin resulting in the dilution of abnormal hemoglobin S (HbS). This may take a long time of up to many months. As a result slow polymerization of HbS occurs and painful conditions are not developed by the sickle cells which are blocking capillaries and causing inadequate supply of oxygen in tissues.
Therapeutic uses:
It is helpful in relieving pain of patients with sickle cell disease.
It is also used to cure chronic type of myelogenous leukemia and polycythemia vera.
Adverse effects:
It may cause suppression of bone marrow and inflammation of the vessels of the skin.
Sargramostim
It is a Hematopoeitic growth factor. It is a granulocyte-macrophage colony stimulating factor (GM-CSF) involved in the increase in granulocyte and macrophages.
Oprelvekin
It is a Hemtopoeitic Growth Factor. It is interleukin-11(IL-11). It is a nonglycosylated protein involved in the increase of platelet count.
Filgrastim
It is an endogenous glycoprotein controlling the production of neutrophils in the bone marrow.
Darbepoetin
It is a Hematopoietic growth factor. Darbepoetin is a longer acting type of erythropoietin which differs from erythropoietin in respect of two additional carbohydrate chains. And because of these two additional chains, its biological activity is increased.
Pharmacokinetics:
Darbepoetin has less value of clearance and have a half life of about three times than that of erythropoietin. It has late start of action and that is why it cannot be used for acute anemia therapy.
Administration:
Sometimes iron is given along with darbepoetin for a better response. Usually subcutaneous route is superior but in the patients undergoing dialysis of kidney it is given intravenously.
Adverse effects:
It may cause hypertension and arthralgia.
Pharmacokinetics:
Darbepoetin has less value of clearance and have a half life of about three times than that of erythropoietin. It has late start of action and that is why it cannot be used for acute anemia therapy.
Administration:
Sometimes iron is given along with darbepoetin for a better response. Usually subcutaneous route is superior but in the patients undergoing dialysis of kidney it is given intravenously.
Adverse effects:
It may cause hypertension and arthralgia.
Erythropoietin
It is Hematopoeitic Growth Factor. It is a glycoprotein. It is usually made in the kidney.
Recombinant DNA technology is done to obtain human erythropoietin.
Mechanism of action:
It activates the multiplication (proliferation) and development of specialized functions (differentiation) of red blood cells by its interaction with particular erythropoietin receptors on the originators of red cells in the bone marrow.
Therapeutic uses:
It is used for the treatment of patients with end stage renal failure, significant anemic conditions caused by human immunodeficiency virus and anemia in patients of cancer.
Adverse effects:
It may cause hypertension and allergic conditions. Thrombotic complications may also develop. Minimum effective dose must not exceed 12g/dL of hemoglobin concentration. As more than 12g/dL of concentration can cause considerable life threatening effects on the heart and finally can lead to death.
Recombinant DNA technology is done to obtain human erythropoietin.
Mechanism of action:
It activates the multiplication (proliferation) and development of specialized functions (differentiation) of red blood cells by its interaction with particular erythropoietin receptors on the originators of red cells in the bone marrow.
Therapeutic uses:
It is used for the treatment of patients with end stage renal failure, significant anemic conditions caused by human immunodeficiency virus and anemia in patients of cancer.
Adverse effects:
It may cause hypertension and allergic conditions. Thrombotic complications may also develop. Minimum effective dose must not exceed 12g/dL of hemoglobin concentration. As more than 12g/dL of concentration can cause considerable life threatening effects on the heart and finally can lead to death.
Folic Acid
It is also called as folacin, folate or pteroylglutamic acid. It is a member of vitamin-B complex family and is essential in the making and maturation of red blood cells. It is present in liver, green vegetables, fruit and yeast, in peptide linkages.
Daily requirements:
Daily folic acid requirement is about 50 µg in normal adults.
Mechanism of action:
Folic acid is a preceding compound for many of the folate cofactors which are important for the synthesis of DNA by the transfer of a carbon atom such as
1. Formation of purine
2. Formation of thymidylic acid from deoxyuridylate
Pharmacokinetics:
Absorption:
Dietary folate in the form of polyglutamate is converted into monoglutamate 5-CH3-H4 folate and it is well absorbed in the proximal jejunum.
It is distributed widely in the body with the help of blood stream. Usually, 5-20 mg of folic acid is preserved in the liver.
Elimination:
More amount of the folic acid, if ingested, is excreted via urine and feces.
Folic acid deficiency:
Its deficiency can be caused by:
1. Greater demand for folic acid such as that in pregnancy or lactation
2. Poor absorption due to any pathological cause of the small intestine
3. Intake of alcohol
4. Dihydrofolate reductase inhibitors such as methotrexate or trimethoprim can also cause its deficiency
Therapeutic uses:
It is used to treat
1. Folic acid deficiency and
2. Megaloblastic anemia which is primarily caused by the decreased production of purines and pyrimidines leading to decreased ability of erythropoietic tissue for the formation of DNA.
Dosage:
It is given in the dose of 1 mg orally per day.
Adverse effects:
It causes no adverse effects as it is immediately excreted through urine.
Daily requirements:
Daily folic acid requirement is about 50 µg in normal adults.
Mechanism of action:
Folic acid is a preceding compound for many of the folate cofactors which are important for the synthesis of DNA by the transfer of a carbon atom such as
1. Formation of purine
2. Formation of thymidylic acid from deoxyuridylate
Pharmacokinetics:
Absorption:
Dietary folate in the form of polyglutamate is converted into monoglutamate 5-CH3-H4 folate and it is well absorbed in the proximal jejunum.
Distribution:
It is distributed widely in the body with the help of blood stream. Usually, 5-20 mg of folic acid is preserved in the liver.
Elimination:
More amount of the folic acid, if ingested, is excreted via urine and feces.
Folic acid deficiency:
Its deficiency can be caused by:
1. Greater demand for folic acid such as that in pregnancy or lactation
2. Poor absorption due to any pathological cause of the small intestine
3. Intake of alcohol
4. Dihydrofolate reductase inhibitors such as methotrexate or trimethoprim can also cause its deficiency
Therapeutic uses:
It is used to treat
1. Folic acid deficiency and
2. Megaloblastic anemia which is primarily caused by the decreased production of purines and pyrimidines leading to decreased ability of erythropoietic tissue for the formation of DNA.
Dosage:
It is given in the dose of 1 mg orally per day.
Adverse effects:
It causes no adverse effects as it is immediately excreted through urine.
Sunday, March 13, 2011
Sphingolipids
They belong to a class of lipids i.e. Membrane lipids. Sphingolipids come from the combination of sphingosine (a long chain base), which is an amino alcohol (and aliphatic in nature), and fatty acid.It is the simplest sphingolipid and is also referred to as sphingoid base. They have a head, which is polar in nature, and two tails, which are nonpolar.
1. Ceramide:
It consists of Fatty acid chain and sphingosine linked through amide linkage. It is ordinarily present in all sphingolipids.
These are the precursors of glycolipids and phospholipids having a wide range of function in the tissues.
2. Sphingophosphlipids
a. Sphingomyelin
It consists of Phosphoethanolamine or phosphocholine and 1-hydroxy group of a ceramide linked through ester linkage.Sphingomyelin is structurally similar to phosphatidylcholine but biologically and physically it is different.
a. Cerebrosides
b. Sulfatides (Sulfated cerebrosides)
c. Globosides
d. Gangliosides
In the first step, Palmitoyl-CoA alongwith serine results into beta ketosphinganine to sphinganine to N-acylsphinganine to Ceramide containing sphingosine to Cerebroside and sphingomyelin.
Sphingomyelin cycle:
Sphingomyelin cycle is used to show a relationship between the metabolic products of sphingolipids.
These are degraded by lysosomal enzymes.
Presence of sphingolipids in Micro-organisms:
Sphingolipids are also found in some genera of bacteria like sphingomonas and sphingobacterium.
Uses of sphingolipids:
They work as the site of adhesion of extracellular proteins. Sphingolipids are important in cell recognition and signal transmission/transduction.
Sphingolipids form the myelin sheath around the nerves in central nervous system.
Diseases in which sphingolipids are involved:
1. Microbial infections
2. Diabetes
3. Alzheimer's disease
4. Certain cancers
5. Some diseases of the respiratory and cardiovascular systems and
6. Some of the neurological syndromes
References:
Murray S. Webb, Marcel B. Bally, Lawrence D. Mayer, James J. Miller, Paul G. Tardi, Sphingosomes for enhanced drug delivery. Patent number: 5814335.
Further Reading:
Delivery System Handbook for Personal Care and Cosmetic Products : Technology, Applications and Formulations (Breakthroughs in Personal Care and Cosmetic Technology) by Meyer R. Rosen
Encyclopedia of Pharmaceutical Technology by James Swarbrick
Hannun, Y. A. 1994. The sphingomyelin cycle and the second messenger function of ceramide. Journal of Biological Chemistry, Vol. 269, No. 5.
http://lipidlibrary.aocs.org/lipids/introsph/index.htm
Copyright (c), 2008, jeepakistan.blogspot.com
The following mnemonic will help you a lot in remembering the structure of shingosine.
Sphingolipids are present in plasma membranes.
Types of sphingolipids:1. Ceramide:
It consists of Fatty acid chain and sphingosine linked through amide linkage. It is ordinarily present in all sphingolipids.
2. Sphingophosphlipids
a. Sphingomyelin
It consists of Phosphoethanolamine or phosphocholine and 1-hydroxy group of a ceramide linked through ester linkage.Sphingomyelin is structurally similar to phosphatidylcholine but biologically and physically it is different.
3. Glycosphingolipids:
a. Cerebrosides
b. Sulfatides (Sulfated cerebrosides)
c. Globosides
d. Gangliosides
Fatty acids in Sphingolipids:
Fatty acids of sphingolipids are completely different from those of glycerolipids. They have very long chains and the number of carbon atoms may range from 25 to 35 in number.
Polyunstaurated fatty acids are rarely present in sphingolipids but sphingomyelins of testes and spermatozoa have this acid.
Monoenoic fatty acids and very long chain fatty acids are producd by specific elongases.
Free long chain fatty acids are converted in to free 2-hydroxy acids in vitro as a result of fatty acid 2-hydroxylase.It is an integral membrane protein of endoplasmic reticulum.
Synthesis of sphingolipids:
Fatty acids of sphingolipids are completely different from those of glycerolipids. They have very long chains and the number of carbon atoms may range from 25 to 35 in number.
Polyunstaurated fatty acids are rarely present in sphingolipids but sphingomyelins of testes and spermatozoa have this acid.
Monoenoic fatty acids and very long chain fatty acids are producd by specific elongases.
Free long chain fatty acids are converted in to free 2-hydroxy acids in vitro as a result of fatty acid 2-hydroxylase.It is an integral membrane protein of endoplasmic reticulum.
Synthesis of sphingolipids:
Synthesis of sphingolipids takes place in Endoplasmic reticulum. Following is the pathway for the synthesis of sphingolipids.
In the first step, Palmitoyl-CoA alongwith serine results into beta ketosphinganine to sphinganine to N-acylsphinganine to Ceramide containing sphingosine to Cerebroside and sphingomyelin.
Sphingomyelin cycle:
Sphingomyelin cycle is used to show a relationship between the metabolic products of sphingolipids.
Free sphingosine and certain other long chain bases work as mediators for many of the cellular processes. Sphingosine 1-phosphate and ceramide 1-phosphate increases mitosis.
Degradation of sphingolipids:These are degraded by lysosomal enzymes.
Presence of sphingolipids in Micro-organisms:
Sphingolipids are also found in some genera of bacteria like sphingomonas and sphingobacterium.
Uses of sphingolipids:
They work as the site of adhesion of extracellular proteins. Sphingolipids are important in cell recognition and signal transmission/transduction.
Sphingolipids form the myelin sheath around the nerves in central nervous system.
Diseases in which sphingolipids are involved:
1. Microbial infections
2. Diabetes
3. Alzheimer's disease
4. Certain cancers
5. Some diseases of the respiratory and cardiovascular systems and
6. Some of the neurological syndromes
References:
Murray S. Webb, Marcel B. Bally, Lawrence D. Mayer, James J. Miller, Paul G. Tardi, Sphingosomes for enhanced drug delivery. Patent number: 5814335.
Further Reading:
Delivery System Handbook for Personal Care and Cosmetic Products : Technology, Applications and Formulations (Breakthroughs in Personal Care and Cosmetic Technology) by Meyer R. Rosen
Encyclopedia of Pharmaceutical Technology by James Swarbrick
Hannun, Y. A. 1994. The sphingomyelin cycle and the second messenger function of ceramide. Journal of Biological Chemistry, Vol. 269, No. 5.
http://lipidlibrary.aocs.org/lipids/introsph/index.htm
Copyright (c), 2008, jeepakistan.blogspot.com
Friday, March 11, 2011
Skeletal system pro
Skeletal system pro
This software is an elearning tools and can be used as a reference for skeletal and ligament studies. This software is helpful in learning a topic in anatomy.
Tags:
iPhone apps, Medical
Further Reading:
http://www.3d4medical.com/Skeletal-System-application_APP1.html
This software is an elearning tools and can be used as a reference for skeletal and ligament studies. This software is helpful in learning a topic in anatomy.
Tags:
iPhone apps, Medical
Further Reading:
http://www.3d4medical.com/Skeletal-System-application_APP1.html
Memory
Memory represents the efficiency of the mind to keep the aquired information and knowledge of the previous occasions and to restore it.
Types of memory:
1. Short term memory
2. Long term memory
Types of memory:
1. Short term memory
2. Long term memory
Mesomeric Effect
Mesomeric effect is the process of electron density redistribution i.e. addition or removal of electron density, occuring, through a pi-orbital through conjugated systems.
Inductive effect
When electron density in a molecule is shifted, as a result of the polarization of a bond by a nearby electropositive or electronegative atom then it is known as inductive effect.
Steric effect
Steric effect is the change in the reactivity and preferred shape of the molecule as a result of the overlapping of electron clouds in a molecule, when atoms are brought closer together.
Hyperconjugation
It is a weak form of conjugation resulted from the ineraction of electrons in a sigma-bond with neighbouring empty pie-orbital or p-orbital resulting in an increased stability of the system.
Conjugation
Basically, Conjugation refers to joining together of two things.
In organic chemistry, we refer conjugation to a system which is joined together with alternate single and multiple bonds.
In organic chemistry, we refer conjugation to a system which is joined together with alternate single and multiple bonds.
Thursday, March 10, 2011
Miracle drug
Miracle drug is a type of drug that can cure incurable disease.
Initially, Aspirin and Penicillin and now Hercpetin, Breast Cancer Drug, is considered as miracle drug.
Initially, Aspirin and Penicillin and now Hercpetin, Breast Cancer Drug, is considered as miracle drug.
Wednesday, March 9, 2011
Efflorescence
It is the loss of water from a crystal.
It means “to flower out” in French.
It is the spontaneous loss of water (or solvent) from a hydrated or solvated salt to the atmosphere on exposure to air, which occurs when the aquous tension of the hydrate is greater than the partial pressure of the water vapor in the air.
Efflorescent:
Denoting a crystalline body that gradually changes to a powder by losing its water of crystallization on exposure to a dry atmosphere.
Explanation:
If the vapor pressure of a hydrated salt is greater than the pressure exerted by the water vapor in the surrounding atmosphere than the salt will attempt to attain equilibrium with its surroundings and therefore tend to lose water to form a lower hydrate or an anhydrous salt.
This phenomenon is known as efflorescence.
The pressure of water vapor in the atmosphere is about 13.33 x 10^2 N/m^2 at 293 K.
Therefore hydrates with vapor pressure greater than this will tend to exhibit efflorescence and be unstable provided that the lower hydrate that if formed still exerts a vapor pressure greater than the surrounding atmosphere.
If this is not so then water will be taken up from the atmosphere by the lower hydrate as fast as it is formed and the final equilibrium will depend on the rates at which water is lost or taken up the two hydrates.
Examples:
The behavior of the various forms of sodium carbonate may be represented by the following scheme:
Na2CO3.10H2O (v.p = 32 x 10^2 N/m^2 at 293K) --> (Spontaneous dehydration i.e. efflorescence) Na2CO3.H2O (v.p. = 16 x 10^2 N/m^2 at 293K)--> (efflorescence not observable because anhydrous salt is rapidly hydrated) --> Na2CO3 (anhydrous) (v.p. = 0)
Since the vapor pressure exerted by the decahydrate is much greater than that of normal atmosphere. It loses water by the process of efflorescence and is converted to the monohydrate.
The vapor pressure of the later is still above that of the atmosphere but further apparent loss of water does not occur. Since the anhydrous salt is rehydrated at a faster rate than dehydration of the monohydrate.
Similarly, vapor pressure of Glauber’s salt (Na2SO4.10H2O) normally exceed that of the water vapor in the atmosphere these salts effloresce and their surface assumes a powdry appearance. Blue stone or blue vitriol (CuSO4.5H2O)is a blue crystalline solid that when exposed to air slowly loses water of crystallization from its surface to form a white layer of anhydrous copper (II) sulfate.
Factors affecting efflorescence:
The vapor pressure of hydrated salts, and therefore the rate of efflorescence increases with rise in temperature.
Pressure of vapors.
Reduction of efflorescence:
Since the instability that arises from efflorescence is caused by the loss of water vapor. The common method of minimizing such deterioration involves the use of containers that present the loss of water vapor.
The additional precautions of using well filled containers with a minimum amount of atmosphere above the efflorescent material and storage in a cool place are also advisable.
It means “to flower out” in French.
It is the spontaneous loss of water (or solvent) from a hydrated or solvated salt to the atmosphere on exposure to air, which occurs when the aquous tension of the hydrate is greater than the partial pressure of the water vapor in the air.
Efflorescent:
Denoting a crystalline body that gradually changes to a powder by losing its water of crystallization on exposure to a dry atmosphere.
Explanation:
If the vapor pressure of a hydrated salt is greater than the pressure exerted by the water vapor in the surrounding atmosphere than the salt will attempt to attain equilibrium with its surroundings and therefore tend to lose water to form a lower hydrate or an anhydrous salt.
This phenomenon is known as efflorescence.
The pressure of water vapor in the atmosphere is about 13.33 x 10^2 N/m^2 at 293 K.
Therefore hydrates with vapor pressure greater than this will tend to exhibit efflorescence and be unstable provided that the lower hydrate that if formed still exerts a vapor pressure greater than the surrounding atmosphere.
If this is not so then water will be taken up from the atmosphere by the lower hydrate as fast as it is formed and the final equilibrium will depend on the rates at which water is lost or taken up the two hydrates.
Examples:
The behavior of the various forms of sodium carbonate may be represented by the following scheme:
Na2CO3.10H2O (v.p = 32 x 10^2 N/m^2 at 293K) --> (Spontaneous dehydration i.e. efflorescence) Na2CO3.H2O (v.p. = 16 x 10^2 N/m^2 at 293K)--> (efflorescence not observable because anhydrous salt is rapidly hydrated) --> Na2CO3 (anhydrous) (v.p. = 0)
Since the vapor pressure exerted by the decahydrate is much greater than that of normal atmosphere. It loses water by the process of efflorescence and is converted to the monohydrate.
The vapor pressure of the later is still above that of the atmosphere but further apparent loss of water does not occur. Since the anhydrous salt is rehydrated at a faster rate than dehydration of the monohydrate.
Similarly, vapor pressure of Glauber’s salt (Na2SO4.10H2O) normally exceed that of the water vapor in the atmosphere these salts effloresce and their surface assumes a powdry appearance. Blue stone or blue vitriol (CuSO4.5H2O)is a blue crystalline solid that when exposed to air slowly loses water of crystallization from its surface to form a white layer of anhydrous copper (II) sulfate.
Factors affecting efflorescence:
The vapor pressure of hydrated salts, and therefore the rate of efflorescence increases with rise in temperature.
Pressure of vapors.
Reduction of efflorescence:
Since the instability that arises from efflorescence is caused by the loss of water vapor. The common method of minimizing such deterioration involves the use of containers that present the loss of water vapor.
The additional precautions of using well filled containers with a minimum amount of atmosphere above the efflorescent material and storage in a cool place are also advisable.
Vitamin B12
It is used for Macrocytic anemia.
It is also called as cobalamin or cyanocobalamin. It is present in liver, milk, egg and fish. Physiologically active forms of vitamin B12 coenzymes are methylcobalamin and 5-deoxyadenosinecobalamine.
Daily requirement:
Daily B12 requirement is about 2 µg in normal adults.
Mechanism of action:
It acts as a co-factor in the formation of Succinyl-CoA from methylmalonyl-CoA.
Methylmalonyl-CoA is an intermediate product during the degradation process of many metabolites in the body. In the case of pernicious anemia, its amount is increased. Whereas, succinyl-CoA is a precursor in the synthesis of heme.
Accumulation of methylmalonyl-CoA leads to abnormal production of fatty acid as well as its incorporation to cell membranes. This causes demyelination of the nerve cells.
It acts as a co-factor in the formation of H4 folate and methionine leading to the formation of DNA.
Accumulation of 5-CH3-H4 folate leads to the deficiency of folate cofactors resulting in reduced DNA synthesis and megaloblastic anemia.
Administration:
It can be administered orally, IM or deep subcutaneously.
Pharmacokinetics:
Absorption:
Vitamin B12 gets bind to intrinsic factor (IF) and form a complex. This IF-B12 complex is then absorbed in distal ileum. This absorption is done by a very specific receptor mediated transport system.
Distribution:
Vitamin B12 is distributed to different cells of the body upon binding to transcobalamin II. It is stored in the liver in amount of 300-500 µg.
Elimination:
Normally, very little amount is excreted through urine or feces but upon parenteral administration large amount is found in urine.
Vitamin B12 deficiency:
Its deficiency causes pernicious anemia due to spoiled synthesis of red blood cells. Its deficiency can be caused by:
1. Low level of intake of Vitamin B12
2. Decreased absorption of vitamin due to less amount of intrinsic factor (IF) produced by gastric parietal cells
3. Lessened activity of the receptor for uptake of the vitamin from intestine
4. Non-specific malabsorption syndrome.
Therapeutic uses:
It is used in megaloblastic anemia and pernicious anemia as it is important in the formation of blood and growth. It is also important in proper neural functioning.
Dosage:
It is given in the dose of 100-1000 µg daily for 1-2 weeks than as a maintenance therapy the same dose is required once a month for life.
Adverse effects:
It has no adverse effects as extra amount is excreted via urine.
It is also called as cobalamin or cyanocobalamin. It is present in liver, milk, egg and fish. Physiologically active forms of vitamin B12 coenzymes are methylcobalamin and 5-deoxyadenosinecobalamine.
Daily requirement:
Daily B12 requirement is about 2 µg in normal adults.
Mechanism of action:
It acts as a co-factor in the formation of Succinyl-CoA from methylmalonyl-CoA.
Accumulation of methylmalonyl-CoA leads to abnormal production of fatty acid as well as its incorporation to cell membranes. This causes demyelination of the nerve cells.
It acts as a co-factor in the formation of H4 folate and methionine leading to the formation of DNA.
Accumulation of 5-CH3-H4 folate leads to the deficiency of folate cofactors resulting in reduced DNA synthesis and megaloblastic anemia.
Administration:
It can be administered orally, IM or deep subcutaneously.
Pharmacokinetics:
Absorption:
Vitamin B12 gets bind to intrinsic factor (IF) and form a complex. This IF-B12 complex is then absorbed in distal ileum. This absorption is done by a very specific receptor mediated transport system.
Distribution:
Vitamin B12 is distributed to different cells of the body upon binding to transcobalamin II. It is stored in the liver in amount of 300-500 µg.
Elimination:
Normally, very little amount is excreted through urine or feces but upon parenteral administration large amount is found in urine.
Vitamin B12 deficiency:
Its deficiency causes pernicious anemia due to spoiled synthesis of red blood cells. Its deficiency can be caused by:
1. Low level of intake of Vitamin B12
2. Decreased absorption of vitamin due to less amount of intrinsic factor (IF) produced by gastric parietal cells
3. Lessened activity of the receptor for uptake of the vitamin from intestine
4. Non-specific malabsorption syndrome.
Therapeutic uses:
It is used in megaloblastic anemia and pernicious anemia as it is important in the formation of blood and growth. It is also important in proper neural functioning.
Dosage:
It is given in the dose of 100-1000 µg daily for 1-2 weeks than as a maintenance therapy the same dose is required once a month for life.
Adverse effects:
It has no adverse effects as extra amount is excreted via urine.
Dispensing
Dispensing refers to the provision of medicine according to the prescription.
Following steps are involved in a Pharmacy setup:
1. Prescription: Medicines recommended by the physician as a remedy
2. Formulation: Darwing and expressing the medicines and ingredients of the prescription
3. Compounding: Preparing and mixing of the ingredients and/or medicines of the prescription
4. Dispensing: Giving the medicines to the patient. Medicines are given in a container with proper labelling. This label helps the patient for subsequent use of the medicine.
Dispensing may also involve the preparation of device for the use of patients.
Extemporaneous dispensing:Extemporaneous dispensing refers to the compounding and dispensing of medicines with little or no preparation in response to the stimulus of one's immediate environment.
Following steps are involved in a Pharmacy setup:
1. Prescription: Medicines recommended by the physician as a remedy
2. Formulation: Darwing and expressing the medicines and ingredients of the prescription
3. Compounding: Preparing and mixing of the ingredients and/or medicines of the prescription
4. Dispensing: Giving the medicines to the patient. Medicines are given in a container with proper labelling. This label helps the patient for subsequent use of the medicine.
Dispensing may also involve the preparation of device for the use of patients.
Extemporaneous dispensing:Extemporaneous dispensing refers to the compounding and dispensing of medicines with little or no preparation in response to the stimulus of one's immediate environment.
Tuesday, March 8, 2011
Search Methods
Search methods are used in optimization.
In these methods, the response surfaces are examined by different methods in order to determine the combination of independent variables, so that the optimum results can be obtained. Response surface methodology is used to determine the connection between different explanatory variables (independent variables) and one or more of the response variables (dependent variables).
Following steps are followed in the search methods:
1. A system is selected
2. Independent and Dependent variables are selected
3. Experiments are performed and product is tested
4. Data is submitted (to computer) for statistical and regression analysis
5. Specifications are set for feasibility program
6. Constraints are set for grid search
7. Grid search printouts are evaluated
8. Partial derivative plots (single or composite) and contour plots are evaluated.
In these methods, the response surfaces are examined by different methods in order to determine the combination of independent variables, so that the optimum results can be obtained. Response surface methodology is used to determine the connection between different explanatory variables (independent variables) and one or more of the response variables (dependent variables).
Following steps are followed in the search methods:
1. A system is selected
2. Independent and Dependent variables are selected
3. Experiments are performed and product is tested
4. Data is submitted (to computer) for statistical and regression analysis
5. Specifications are set for feasibility program
6. Constraints are set for grid search
7. Grid search printouts are evaluated
8. Partial derivative plots (single or composite) and contour plots are evaluated.
Iron compounds (Pharmacology)
Iron occurs as tin in the liver and spleen from where it is released and utilized in the heme portion of hemoglobin, which constitutes about 65 % of the total iron in the body.
Daily requirement:
Daily iron requirement is about 0.5-1mg in normal adults.
Mechanism of action:
In the first step, Heme portion of hemoglobin is formed.
In the second step, Hemoglobin is formed.Hemoglobin is the compound for the transportation of oxygen from the lungs to the tissues.
Administration:
It can be given orally or parenterally.
Pharmacokinetics:
Absorption:
It is readily absorbed from duodenum and proximal jejunum. It is more easily absorbed in the form of ferrous ions (Fe2+) than ferric ions (Fe3+).
Distribution:
Ferrous ion is converted into ferric ion and is actively transported in the mucosal cells of the intestine. It is actively transported into the plasma through transferrin. In the liver and spleen, it is converted to ferritin and hemosiderin with the help of certain proteins and get stored.
Elimination:
Approximately 1 mg of the iron is wasted, by the shedding of the tissue surface of the intestinal mucosal cells, through feces and little amount is excreted via urine, sweat and bile.
Iron deficiency:
Iron deficiency occurs in:
1. Chronic or acute loss of blood
2. Inadequate taking in of iron by the children during the period of rapid growth
3. In severely menstruating or pregnant woman.
Therapeutic uses:
The above mentioned deficiencies can be removed by taking sufficient amount of iron in the form of its compounds from outside.
Oral iron preparations can be used for infants and the children in the period of rapid growth as well as for pregnant and lactating women. Whereas parenteral preparations can be taken by the patients who are unable to take orally or who have chronic or acute blood loss.
Dosage:
Oral preparations of iron such as ferrous fumarate, ferrous gluconate and ferrous sulfate can be taken as 3-4 tabs per day in divided doses. Whereas, parenteral preparation is available in the form of iron-sorbitol-citric acid complex and can be taken as 1.5 mg/kg IM upto a maximum of 100 mg per injection in single daily dose.
Adverse effects:
Oral iron preparations can cause nausea, constipation, abdominal cramps and epigastric discomfort. Whereas, parenteral preparations can cause headache, nausea, vomiting, fever, flushing, local pain and tissue staining.
Daily requirement:
Daily iron requirement is about 0.5-1mg in normal adults.
Mechanism of action:
In the first step, Heme portion of hemoglobin is formed.
In the second step, Hemoglobin is formed.Hemoglobin is the compound for the transportation of oxygen from the lungs to the tissues.
Administration:
It can be given orally or parenterally.
Pharmacokinetics:
Absorption:
It is readily absorbed from duodenum and proximal jejunum. It is more easily absorbed in the form of ferrous ions (Fe2+) than ferric ions (Fe3+).
Distribution:
Ferrous ion is converted into ferric ion and is actively transported in the mucosal cells of the intestine. It is actively transported into the plasma through transferrin. In the liver and spleen, it is converted to ferritin and hemosiderin with the help of certain proteins and get stored.
Approximately 1 mg of the iron is wasted, by the shedding of the tissue surface of the intestinal mucosal cells, through feces and little amount is excreted via urine, sweat and bile.
Iron deficiency:
Iron deficiency occurs in:
1. Chronic or acute loss of blood
2. Inadequate taking in of iron by the children during the period of rapid growth
3. In severely menstruating or pregnant woman.
Therapeutic uses:
The above mentioned deficiencies can be removed by taking sufficient amount of iron in the form of its compounds from outside.
Oral iron preparations can be used for infants and the children in the period of rapid growth as well as for pregnant and lactating women. Whereas parenteral preparations can be taken by the patients who are unable to take orally or who have chronic or acute blood loss.
Dosage:
Oral preparations of iron such as ferrous fumarate, ferrous gluconate and ferrous sulfate can be taken as 3-4 tabs per day in divided doses. Whereas, parenteral preparation is available in the form of iron-sorbitol-citric acid complex and can be taken as 1.5 mg/kg IM upto a maximum of 100 mg per injection in single daily dose.
Adverse effects:
Oral iron preparations can cause nausea, constipation, abdominal cramps and epigastric discomfort. Whereas, parenteral preparations can cause headache, nausea, vomiting, fever, flushing, local pain and tissue staining.
Anti-Anemic Drugs
Anti-anemic drugs are those agents, which are used for the treatment of anemic conditions.
Classification of Anti-anemic drugs:
Iron compounds:
Ferrous fumarate, Ferrous gluconate, Ferrous sulfate, Iron dextran Injection, Polyferose
Agents for Macrocytic anemia:
Vitamin B12, Folic Acid, Folinic Acid
Hematopoeitic growth factors:
Erythropoietin:
Epoetin alpha, Darbepoetin alpha
Granulocyte colony stimulating factor:
Filgrastim
Granulocyte-Macrophage colony stimulating factor:
Sargramostim
Interleukin:
Interleukin 3, Oprelvekin
Agent for Sickle cell anemia:
Hydroxyurea
Anemia
A disease of blood deficiency in which the red blood cell count is decreased resulting in poor health. In this condition, the number of red blood cells per millimeter cube or the amount of hemoglobin in 100 ml of blood is less than normal. It may also be caused by a decrease in the size of red blood cells. The mean corpuscular volume in a normal person is 82-92 µm3.
Anemia shows the following symptoms:
1. Paleness of the skin as well as mucous membranes
2. Short breath
3. Irregular or fast rate of heart beat
4. Soft systolic fluttering sound in the chest
5. Tending to become extremely tired
Main types of anemia:
There are almost 100 various types of anemia. According to the structure, anemia is of the following types:
Macrocytic anemia:
It is the type of anemia in which the size of red blood cells is larger than the normal such as in pernicious anemia. Pernicious anemia is the result of deficient intrinsic factor.
Normocytic anemia:
It is the type of anemia caused by the decrease in the number of red blood cells but the size is normal. Anemia caused by sudden blood loss is a normocytic anemia.
Microcytic anemia:
It is the type of anemia in which the average size of the red blood cell is reduced.
Simple microcytic anemia:
It is marked by smaller than normal red cells. It is found in chronic inflammatory conditions as well as in renal disease.
Microcytic hypochromic anemia:
It is marked not only by decreased red cell size but also by the decrease in hemoglobin concentration. It is seen in iron deficiency anemia and in thalassemia.
Anemia shows the following symptoms:
1. Paleness of the skin as well as mucous membranes
2. Short breath
3. Irregular or fast rate of heart beat
4. Soft systolic fluttering sound in the chest
5. Tending to become extremely tired
Main types of anemia:
There are almost 100 various types of anemia. According to the structure, anemia is of the following types:
Macrocytic anemia:
It is the type of anemia in which the size of red blood cells is larger than the normal such as in pernicious anemia. Pernicious anemia is the result of deficient intrinsic factor.
Normocytic anemia:
It is the type of anemia caused by the decrease in the number of red blood cells but the size is normal. Anemia caused by sudden blood loss is a normocytic anemia.
Microcytic anemia:
It is the type of anemia in which the average size of the red blood cell is reduced.
Simple microcytic anemia:
It is marked by smaller than normal red cells. It is found in chronic inflammatory conditions as well as in renal disease.
Microcytic hypochromic anemia:
It is marked not only by decreased red cell size but also by the decrease in hemoglobin concentration. It is seen in iron deficiency anemia and in thalassemia.
Monday, March 7, 2011
Science Research Ideas: Biology
It is still to find out that how the actual replication initiation machinery is taken up by the replication origin. Here the actual replication initiation machinery can be replication protein-A or DNA polymerase a-primase.
The mechanism by which the components of the initiation complex such as Cdc45p or Mcm proteins become part of the elongating replication fork is still not clear.
It is still unclear that whether the protein-DNA interactions, found at the lamin B2 origin, are due to pre-RC (i.e. at the time of G1 phase) and post-RC (i.e. at the time of S phase) formation. But recent studies (RIP mapping analyses) show that the replication start points are close to the site of protein-DNA interaction.
It is still to be found whether Cdc6p and other proteins change origin recognition complex (ORC) binding in higher eukaryotes and whether this change affect the origin choice at the "Origin decision point" in mammalian cells.
It is still not clear whether ORCs of highly developed organisms recognize structural features or specific sequences.
The mechanism by which the iron rule of initiating DNA replication i.e. once and only once per cell cycle, predominates is still not known.
The relationship between replication start sites and the ORC binding sites is still unclear as the initiation pattern of the chorion origin at the nucleotide level is still to be determined. (Chorion is the outermost membrane around the embryo).
It is still to be found whether HoxC10p and HoxC13p (Proteins involved in morphogenesis of multicellular organisms) can bind to the ORC binding site.
Lagging strand (Okazaki fragment) start sites do not share any consensus sequence, even within a given gene position, and the mechanism underlying their regular spacing is still unclear.
References:
Bielinsky, A. K., & Gerbi, S. A. (2001). Where it all starts: eukaryotic origins of DNA replication. Journal of Cell Science , 643-651.
Tag:
Biology, Year 2001
The mechanism by which the components of the initiation complex such as Cdc45p or Mcm proteins become part of the elongating replication fork is still not clear.
It is still unclear that whether the protein-DNA interactions, found at the lamin B2 origin, are due to pre-RC (i.e. at the time of G1 phase) and post-RC (i.e. at the time of S phase) formation. But recent studies (RIP mapping analyses) show that the replication start points are close to the site of protein-DNA interaction.
It is still to be found whether Cdc6p and other proteins change origin recognition complex (ORC) binding in higher eukaryotes and whether this change affect the origin choice at the "Origin decision point" in mammalian cells.
It is still not clear whether ORCs of highly developed organisms recognize structural features or specific sequences.
The mechanism by which the iron rule of initiating DNA replication i.e. once and only once per cell cycle, predominates is still not known.
The relationship between replication start sites and the ORC binding sites is still unclear as the initiation pattern of the chorion origin at the nucleotide level is still to be determined. (Chorion is the outermost membrane around the embryo).
It is still to be found whether HoxC10p and HoxC13p (Proteins involved in morphogenesis of multicellular organisms) can bind to the ORC binding site.
Lagging strand (Okazaki fragment) start sites do not share any consensus sequence, even within a given gene position, and the mechanism underlying their regular spacing is still unclear.
References:
Bielinsky, A. K., & Gerbi, S. A. (2001). Where it all starts: eukaryotic origins of DNA replication. Journal of Cell Science , 643-651.
Tag:
Biology, Year 2001
Science Research ideas
In Eukaryotic cells, DNA synthesis starts at different places of chromosomes. Scientists have still to find the relationship between sites of initiation of replication and replication licensing factor i.e. protein or proteins allowing the replication origin to start DNA replication at that site. It was clear that replication licensing are not specific for particular replication origins.
Work on the genetic origin in higher eukaryotes is still in progress. Infact it is to be found that whether genetic origins of DNA replication exist in higher eukaryotes or not. Different opinions are found in the scientific literature on the specific sequences for origins on studying the DNA replication of metazoan.
Functional origins of replication are shown to be present in higher eukaryotes but the properties are still to be found.
It is still unclear that how the replication process takes place in replication systems which are cell free such as SV40 virus in-vitro replication system. Some work has been done.
It has been suggested to work on the nuclear structure participation in the regulation of the DNA replication as this can be a shining topic in the near future.
Reference:
Rui, W. J. (1999). Regulation of eukaryotic DNA replication and nuclear structure. Cell Research , 163-170.
Tag: Biology, Year 1999
Work on the genetic origin in higher eukaryotes is still in progress. Infact it is to be found that whether genetic origins of DNA replication exist in higher eukaryotes or not. Different opinions are found in the scientific literature on the specific sequences for origins on studying the DNA replication of metazoan.
Functional origins of replication are shown to be present in higher eukaryotes but the properties are still to be found.
It is still unclear that how the replication process takes place in replication systems which are cell free such as SV40 virus in-vitro replication system. Some work has been done.
It has been suggested to work on the nuclear structure participation in the regulation of the DNA replication as this can be a shining topic in the near future.
Reference:
Rui, W. J. (1999). Regulation of eukaryotic DNA replication and nuclear structure. Cell Research , 163-170.
Tag: Biology, Year 1999
Sunday, March 6, 2011
Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome: It is sudden outburst of tachycardia characterized by short PR interval.
Torsade de pointes syndrome
Torsade de pointes syndrome: A form of ventricular tachycardia characterized by long QT interval.
Supraventricular
Supraventricular: It refers (especially) to impulses generating from above the ventricles such as in the atrium or AV junction.
Refractory period
Refractory period: The time period immediately after a stimulus during which any nerve or cardiac muscle loses the ability to further stimulus of threshold intensity.
Paresthesia
Paresthesia: An unusual or abnormal form of sensation on the skin causing some type of tingling or burning sensation.
Lupus erythematosus
Lupus erythematosus: An inflammatory disease which affects mostly connective tissues. It may cause skin lesions or it may affect the joints or any other internal organs.
Hallucination
Hallucination: A perception or strong imagination of seeing, hearing or other types sensing.
Fibrosis
Fibrosis: An unnatural formation of fibrous tissue or connective tissue as a result of infection or injury.
Epimer
Epimer: It is one of the two molecules which have difference in the arrangement of atoms surrounding a chiral atom.
Ectopic
Ectopic: This is referred for those organs or parts of the body which occur not on their normal position. While denoting to heartbeat, this denotes to developing from other than the sinoatrial node.
Effective refractory period
Effective refractory period: The time period in which there is weak conduction of impulses.
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