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Biomedical subjects

P Bhattacharya

Publications and source records attributed to P Bhattacharya.

At least 73 records · Page 4Linked to original sources
PubMed1981

Differential inhibition of multiple forms of DNA polymerase alpha from IMR-32 human neuroblastoma cells.

Three forms of DNA polymerase (pol) alpha from human neuroblastoma IMR-32 were separated by DEAE column chromatography. All sedimented at approximately 7 S in 5-20% continuous sucrose density gradients. All were heat labile, with pol alpha 2 the most (90% inactivated) and pol alpha 3 the least (50% inactivated) sensitive to heating for 5 min at 50 degrees C. pol alpha 1 and alpha 2 efficiently utilized activated calf thymus DNA as template. The most active form, pol alpha 2, used both poly(dA).(dT)12-18 and poly(dT).(dA)12-18 as template at equal rates. Differential inhibition of DNA polymerase alpha activities was examined in the presence of ricin, hemin, and a nonhistone chromatin protein. All three polymerases were inhibited by both ricin (nonreduced) and hemin, with pol alpha 2 the most (80-90%) and pol alpha 3 the least (60%) sensitive in each case. In contrast, only pol alpha 2 and alpha 3 activities were inhibited (80-85%) by rat liver nonhistone chromatin protein.

Animals↗
PubMed1979

Inhibition of human neuroblastoma DNA polymerase activities by plant lectins and toxins.

The effects of concanavalin A and ricin (RCAII, Mr 65,000) on [3H]thymidine incorporation into human neuroblastoma IMR-32 DNA showed reduction of total DNA synthesis to 50% and 70% of control, respectively. Two DNA polymerase (DNA nucleotidyltransferase, EC 2.7.7.7.) activities (alpha and beta) involved in the biosynthesis in vitro of DNA were separated by sucrose density gradient centrifugation from IMR-32 cell homogenate. The DNA polymerase alpha activity was also purified by selective precipitation with polyethylene glycol (Mr 6000) followed by agarose-concanavalin A column chromatography. The activities of both DNA polymerases were examined at various concentrations of mutagenic and nonmutagenic plant agglutinins and the toxin ricin. Concanavalin A and ricin specifically inhibited DNA polymerase alpha activity (activity reduced to 19% and 10%, respectively), whereas DNA polymerase beta activity was inhibited (reduced to 16%) by red kidney bean agglutinin (PHA-P).

Cell Line↗
PubMed1979

Hospital infections in Port Moresby General Hospital: studies in special care nursery.

Special Care Nursery of Port Moresby General Hospital has been experiencing too many infections particularly deaths from Septicaemia due to gram negative organisms. Bacteriological Survey in the Nursery reveals presence of too many pathogenic bacteria in the Nursery--in air, in beds, in incubators, in sinks--almost all over the Nursery. It also reveals that Nursing mothers and a good number of hospital workers are, in fact, carriers of dangerous pathogens. Proper cleaning and restructuring of the ward is essential. Based on the results of the study, measures have been recommended to deal with the situation.

Cross Infection↗
PubMed1978

DNA polymerase activities in differentiating mouse neuroblastoma N-18 cells.

The activities of two DNA polymerases (DNA nucleotidyltransferases) were characterized in mouse neuroblastoma clone N-18 on the basis of their apparent molecular weights (determined by sucrose density gradient centrifugation: polymerase-alpha, 7.5-8 S; polymerase-beta, 3-4 S) and relative inhibition by sulfhydryl-blocking agents. N-Ethylmaleimide (10 mM) and iodoacetamide (1.5 mM) inhibited DNA polymerase-alpha activity completely, whereas only 35-40% inhibition was observed for DNA polymerase-beta under similar conditions. DNA polymerase-alpha activity was reduced 50-70% in N-18 cells that had been induced to differentiate by 4 micro M bromodeoxyuridine, and the low molecular weight DNA polymerase-beta activity remain unchanged. With activated calf thymus DNA as template, only DNA polymerase-alpha activity was stimulated in the presence of added ribonucleotides and purified Escherichia coli RNA polymerase.

Bromodeoxyuridine↗
PubMed1978

Hypertrophic tuberculosis of the vulva.

Hypertrophic tuberculosis vulvae is a rare genital infection. Treatment is essentially with antitubercular drugs. However, when the hypertrophy is so excessive that it interferes with normal life, surgical treatment is necessary. A case is presented in which combined treatment by surgery and antitubercular drugs restored the patient's health.

Adult↗
PubMed1977

Process engineering studies on immobilized trypsin using molecular sieves as carriers.

In the present investigation molecular sieve has been found to be a suitable carrier for the immobilization of enzymes. From the present study it may be specifically found that trypsin and pappain can be immobilized by molecular sieve type 4a following a very simple techniqure. The immobilized enzyme can be used both in packed as well as in a continuous stirred tank reactor (CSTR).

Enzymes, Immobilized↗
PubMed1977

Embryonic chicken brain and mouse neuroblastoma cells N1E-115 and N-18 contain an inhibitor of acid deoxyribonuclease.

Activity of a trypsin-sensitive acid deoxyribonuclease (DNase) inhibitor has been detected in 13- to 21-day-old embryonic chicken brains and in clonal lines of neuroblastoma cells (adrenergic, N1E-115, and neurotransmitter-inactive, N-18) grown for 48 hr after subculture. The activities of purified porcine and bovine spleen DNases were inhibited 60--75% in the presence of the inhibitor, whereas less than 10% inhibition was observed with purified pancreatic DNase. Activities of an acidic DNase and its inhibitor reached maxima in 21-day-old embryonic chicken brain. The proteins were separated by isoelectric focusing and affinity column chromatographic techniques. The pI values of the acid DNase and its inhibitor were 5.4 and 4.2, respectively.

Animals↗