Investigation of buffalopox outbreaks in Maharashtra State during 1992-1996.

During 1992-96, outbreaks of buffalopox zoonosis were reported from different villages in Jalgaon, Dhule and Beed districts of Maharashtra State. In humans, pox lesions were observed on the hands whereas in affected buffaloes and cows the lesions were noticed mainly on the teats and udder. Twenty two virus strains were isolated from the skin scabs collected from infected humans and milch animals. Neutralizing antibodies were detected not only in the sera of affected humans but also in their contacts. Detection of antibodies in young individuals from endemic area, who were neither vaccinated for smallpox nor had any contact with buffaloes or history of any poxvirus disease, is suggestive of occurrence of subclinical infection. A few children who had no contact with infected animals also showed clinical manifestations with disseminated lesions on the face, arm and buttocks, and thus suspected to have acquired infection through their infected parents or other family members indicating a possible man to man transmission. Therefore, in the light of discontinuation of smallpox vaccination, buffalopox outbreaks need to be monitored carefully as this may emerge as a serious zoonotic disease in India.

Multiple neural inductions in area opaca by grafts of the Hensen's node do not retard host chick embryo development.

Four hundred and forty four full primitive streak stage chick embryos were cultured in vitro and 261 were transplanted with 1, 3 or 5 Hensen's nodes in the area opaca. Irrespective of the number of grafts, neural induction was observed in 90% cases. The development of control and grafted embryos and the size of blastoderm area were monitored at the time of grafting and after 20 hr. We find that the induced neural tissue and differentiated tissue of graft-origin neither fuse with the host embryonic axis, nor retard its development.

A study of phenobarbital and dilantin in neonatal seizures.

A total of 40 cases of neonatal convulsions of different nonmetabolic aetiological factors were studied. Patients with kernicterus were included in the study. Peak plasma phenobarbital concentrations after incremental loading doses of phenobarbital i.e. 10 mg/kg, 15 mg/kg, and 20 mg/kg were determined. Diphenylhydantoin was added if phenobarbital alone was unable to control seizures. In three patients, a combination of phenobarbital and diphenylhydantoin was used as the initial loading therapy. Increase in the loading dose of phenobarbital was associated with an increase in its peak plasma concentration. Despite increase in the plasma phenobarbital concentration beyond the 'therapeutic' levels suggested by the Western studies, doses of 15 mg/kg and 20 mg/kg of phenobarbital were unable to score over the traditional regimen of 10 mg/kg. Convulsions were controlled in 50% of the patients with any of these three regimens, irrespective of the aetiology. Convulsions were controlled in 7 out of the 9 cases where diphenylhydantoin was added, because of the failure of phenobarbital in controlling the convulsions as a single drug. Convulsions of all the three patients, in whom a combination of phenobarbital and diphenylhydantoin was used by random selection as the initial bolus, were controlled. Seizure effects were difficult to distinguish from drug effects but major side effects were not encountered despite the fluctuating drug levels in the sick neonate.

"An analysis of epileptic patients nonresponsive to drugs".

Fifty-four consecutively referred patients with uncontrolled epilepsy were subjected to Therapeutic Drug Monitoring on an out patient basis. Regular 2 weekly follow up for a minimum period of 2 months was done, after altering the drug dosage and bringing plasma level(s) within therapeutic range. Plasma levels of Phenobarbitone, Phenytoin and Carbamezepine were done by High Pressure Liquid Chromatography. Eventually, 24 patients were controlled and 30 remained uncontrolled. Significant differences between these 2 groups were found, as regards, duration of epilepsy (p < 0.01), associated mental retardation (p < 0.02), initial carbamazepine dosage and plasma levels in patients on carbamazepine montherapy (p < 0.02 and P < 0.01, respectively) and final phenytoin plasma levels in patients on combined therapy with phenobarbitone and phenytoin (p < 0.05). This study emphasizes the importance of early diagnosis and treatment of epilepsy with the help of plasma level monitoring of anti-epileptic drugs.

Food reduces isoniazid bioavailability in normal volunteers.

Food and drug interaction is a major variable in bioavailability of drugs. Isoniazid is the most common antitubercular drug used in India. We studied the effect of standard Indian breakfast and lunch on the bioavailability of isoniazid in a single dose crossover study in normal male volunteers. The standard breakfast and lunch significantly reduced plasma AUC, Cmax and Kabs values of isoniazid. Isoniazid, thus, should not be administered with food.

Need for 25 mg tablets of phenytoin.

Phenytoin is widely used for the treatment of generalized tonic clonic and partial seizures. Monitoring of serum phenytoin levels is essential to optimize therapy. Of 320 patients monitored, 190 patients whose seizures were uncontrolled were followed up before and after dosage adjustment was carried out. Plasma phenytoin estimation was done by HPLC method. Of all the patients receiving the drug, 20% and 8% of patients were finally on dosages requiring 50 and 25 mg fraction administration respectively. Administration of 100 mg fractions resulted in either loss of seizure control or toxicity. This emphasizes the need for providing tablets of 25 mg strength, presently not available in this country.

Isonicotinic acid hydrazide inhibits cell population growth during teratogenesis of chick embryo.

In chick embryos treated with a 4 hr pulse of 7.2 X 10(-5) M isonicotinic acid hydrazide (INH) the cell population growth is inhibited with an increased population doubling time. Teratogenised blastoderm cells complete their ongoing cell cycle and arrest in G1 phase. A chase with an equimolar concentration of pyridoxal-5-phosphate restores the growth rate after a lag of 4 hr equivalent to the duration of treatment with INH. Presumptive mesoblast cells invaginated through the primitive streak and neuroectoblast cells induced prior to the application of INH differentiate, while the teratogen inhibits morphogenesis and organization of organ primordia.