Hypertension

It is an arterial disease accompanied by abnormally high blood pressure. It is also called as “Hyperpiesis” or “Hyperpiesia”.

Systolic pressure:

Persistent systolic blood pressure at about 140 mmHg or greater

Diastolic pressure:
Persistent diastolic blood pressure at about 90 mmHg to 110 mmHg

After effects of hypertension:
1. Congestive cardiac failure
2. Myocardial infarction
3. Renal damage
4. Other cerebrovascular disorders.

Levigation

Definition:


Levigation is the process of grinding an insoluble substance to a fine powder.

Or

Levigation is the grinding to a powder of a moist or hard substance.

Explanation:

The material is introduced into the mill together with water in which the powdered substance remains suspended and flows from the mill as a turbid liquid or thin pastes. According to the amount of water employed. There is no loss of material as dust nor injury or annoyance to the workmen.

Further any (substances) soluble impurities in the substance are dissolved and the product thereby purified.

Advantages of levigation:

The greatest advantages of levigation is the facility it affords for the subsequent separation of the products into various grades of fitness because of slower. Subsidence of the finer particles from suspension.

The turbid liquid flows into the first of a series of tanks and is allowed to stand for a time. The coarsest and heaviest particles quickly subside leaving the finer material suspended in the water which is drawn from above the sediment into the next tank.

The liquid is passed from tank to tank remaining in each longer than it remained in the proceeding since the finer and higher the particles the more time is necessary for this deposition. In some cases a dozen or more tanks may be used and the process then becomes exceedingly slow.

The term levigation is now often applied to more sedimentation a substance being simply stirred up in water without previous wet grinding.

Calcination

Definition:
The process of heating a substance to a high temperature but below the melting point or fusing point causing loss of moisture reduction or oxidation and dissociation. Into simpler substances, the term was originally applied to the method of driving off carbon dioxide from limestone to obtain lime.

Calcination is also used to extract metals from ores.

Or

To heat a substance to a high temperature but below the melting point or fusing point causing loss of moisture, reduction or oxidation and the decomposition of carbonates and other compounds.

Explanation:
Calcination also referred to as calcining a thermal treatment process applied to ores and other solid materials in order to bring about a thermal decomposition phase transition or removal of a volatile fraction. The calcinations process normally takes place at temperatures below the melting point of the product materials.

Calcination is to be distinguished from roasting. In which more complex gases, solids reactions takes place between the furnace and the solids.

Calcination reactions:
Calcinations reaction usually takes place at or above the thermal decomposition temperature or transition temperature. This temperature is usually defined as the temperature at which the standard energy of reaction for a particular calcination reaction is equal to zero.

Example:
Examples of chemical decomposition reactions common in calcination processes and their respective thermal decomposition temperature include
CaCO3 = CaO + CO2 : 484ºC

Occurance:
Calcination occur under layers of hot volcanic ash.

Physical properties:
The physical properties which involves bulk density, total pore volume, and the pore size distribution of the calcines prepared under different conditions were determine by using a Mercury porosimeter.
It was found that the physical properties of calcines were dramatically affected by the calcinations conditions, at high calcination temperature, because of sintering and shrinking affects, a decrease in properties. An increase in bulk density and average pore radius were observed.

Wonders of Placebo

Placebo refers to a drug having no active ingredient for therapy and which is given to benefit the patient psychologically such as it can be a simple glass of water but the patient is told that this water contains medicine. It is related to positive thinking. Placebo is still a wonder for scientific community.

Data on placebos is holding such an attention that many physicians in America (one study estimates 50 percent) secretly give placebos to unsuspecting patients.

In a study it was found that amond 435 patients of headache reported by branded placebo users, 64% were reported as improved 1 hour after pill administration compared with only 45% of the 410 headaches reported as improved among the unbranded placebo users. So they found that branding of a drug even have more effect on the treatment of a particular disease.

It has been found that placebo works even better, if a doctor give this to a patient.

Share
|

References:
Harvard Medical School (2010, December 23). Placebos work -- even without deception. ScienceDaily. Retrieved April 5, 2011, from http://www.sciencedaily.com­ /releases/2010/12/101222173033.htm

Moerman, D. E.; Jonas, W. B.; Deconstructing the Placebo Effect and Finding the Meaning Response. Annals of Internal Medicine, 2002, Vol. 136, No. 6. Pages 471-476.

Ondansetron

It is a serotonin receptor antagonist.


Mechanism of action:
It has been shown to inhibit 5-HT3 receptors both centrally and peripherally and thus showing its anti-emetic activity.

It has been found that the chemotherapy causes degradative changes in the GI tract such as small intestine that causes the increased release of serotonin which then stimulates vagal and splanchnic nerves which leads to vomting center of the brain inducing vomiting.

The same stimulation has been found in the area postrema.

Ondansetron stops acute chemotherapy induced emesis by the inhibition of visceral afferent stimulation from the vomting center which may be:

1. Indirectly at the level of the area postrema

2. Directly inhibiting serotonin activity within the area postrema and chemoreceptor trigger zone.

Therapeutic uses:
It is used for Nausea and vomiting, which may be due to:

1. Cancer chemotherapy

2. Postoperative

3. Radiation induced.

Administration and dosage:
It can be administered orally or IV. The usual oral dose for cancer chemotherapy induced vomiting is 8 mg 30 minutes prior to chemotherapy induced vomiting.

Adverse effects:
It may cause headache, dizziness, restlessness and diarrhea (in some patients it may cause constipation). Fever and injection site reactions have also been reported.

Phenothiazine

These are also dopamine receptor antagonists.


Mechanism of action:
It is thought to affect the chemoreceptor trigger zone causing the blockage of dopamine receptors in the chemoreceptor trigger zone. It causes the inhibition of apomorphine induced vomiting.

Therapeutic uses:
It is effective in the treatment of nausea and vomiting which may be post operative or due to toxins or chemicals. It can be used in the treatment of acute migraine attacks and nausea and vomiting coming after the attacks.

It is also used as an antipsychotic drug.

Administration and dosage:
It can be administered orally or parenterally. The usual dosage of prochlorperazine is about 5 or 10 mg, 3-4 times daily.

Pharmacokinetics:
The onset of action of prochlorperazine is 30-45 minutes. The duration of action of prochlorperazine tablets is about 2.5-4.5 hours.

Adverse effects:
It may cause extrapyramidal reactions, tardive dyskinesia, hypotension and drowsiness.

Dimenhydrinate

It is an ethanolamine H1-receptor antagonist.


Mechanism of action:
Dimenhydrinate is thought to inhibit acetylcholine. It inhibits vestibular stimulation. (Vestibular and reticular systems stimulates nausea and vomiting in motion sickness.)

Therapeutic uses:
It is used to treat motion sickness. It is also used in Meniere’s disease and some of the other vestibular disturbances. It has been used in the allergic conditions also.

Administration and Dosage:
It can be administered orally, IM or IV. In motion sickness 50 mg of the drug is taken 30 minutes before motion. For vomiting 50-100 mg is taken 4-6 times in 24 hours.

Pharmacokinetics:
Its duration of action is 2.5-6 hours. It is widely distributed in the body cavities. It can cross the placenta. It is metabolized in liver and excreted through urine.

Adverse effects:
It may cause drowsiness, headache, dryness of the mouth and respiratory passages.