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Biomedical subjects

P Chandra

Publications and source records attributed to P Chandra.

At least 91 records · Page 5Linked to original sources
PubMed1984

Factors affecting the choice of anesthesiology by medical students for specialty training.

To learn some of the reasons why anesthesiology as a specialty is not preferred by more graduating medical students and to determine the effects of various factors on their specialty choice, the authors studied the number of medical students who chose anesthesiology as a specialty after graduation and the quality of clerkships available in various departments. The study established that medical students do not find anesthesiology as attractive as other specialties and that several factors are related to the students' choice of anesthesiology. Most surprising was the negative effect of the presence of certified registered nurse anesthetists on the operating room floor. These results suggest the need for a thorough study of the use of nurse practitioners, physician's assistants, and nurse-clinicians, at least where teaching of medical students is taking place.

Anesthesiology↗
PubMed1983

The significance of certain epidemiological variants in the genesis of juvenile insulin-dependent diabetes mellitus--the need for a global program of co-operation.

Published data from literature show a two-to four-fold increase in the incidence of JIDDM, in the Western hemisphere over the past decade (5% to 10-20%). WHO Expert Committee Technical Report Series No. 646 (1980) gives the risk of development of diabetes in the first two decades of life, in the sub-populations of Europe and North America, as 0.1% to 0.3%. In Japan, it is stated to be less than 0.02%; in Tamil Nadu, India, we have calculated the risk to be less than 0.01%. The incidence of JIDDM amongst diabetics in urban Southern India has remained low and static in the last decade; 0.8% and 0.84% in 1973 and 1981 respectively. This is so, despite the fact that infant and perinatal mortality rates over the past two decades have registered a sharp decline in our area. Childhood diabetes and its complications have not shown an uptrend in hospital admissions or infant mortality analysis. It is speculative that our ethnic group is lacks the genetic factor, Bf F1 (which is strongly linked with HLA B18 and IDDM) and the increased association of S1. It remains to be elucidated whether the increased susceptibility to JIDDM of Caucasian children may be associated with a genetic factor or some other exogenous factor, Such as a nutritional factor or virus infection. A plea is made to exchange groups of diabetic children and study the "behavior" of their diabetes under different environments.

Child↗
PubMed1983

Role of the perineurium and glial lacunar system in nutrition and storage of nutrients in the central nervous system of Spodoptera litura Fabr. (Lepidoptera: Noctulidae) at the time of reorganisation of the neural lamella during metamorphosis.

Brains and nerve cords of Spodoptera litura (Fabr.) of various stages during metamorphosis were tested for acid mycopolisaccharides (AMPS), PAS-positive substances, glycogen, proteins and lipids. During reorganisation of the neural lamella in pupal period glycogen and PAS-positive substances are stored in perineurium and AMPS in the glial lacunar system (GIS) and below the perineurium as a thin layer. Lipids and AMPS diffuse in the GIS. The perineurium and GIS serve for the passage as well as storage of nutrients. In neuropile, only proteins are present. Significances of these findings is discussed.

Animals↗
PubMed1983

Growth of ovine granulocyte-macrophage precursors in vitro without exogenous colony-stimulating activity.

Ovine granulocyte-macrophage colony-forming units (CFU-GM) from peripheral blood and bone marrow were cultured in vitro. The colony-stimulating activity (CSA) was provided by various conditioned-media previously reported to contain CSA and by homologous sheep serum (SS). The maximum number of CFU-GM was observed in the cultures containing SS without the addition of exogenous CSA. The CFU-GM appeared earlier in the cultures containing bone marrow cells when compared to the peripheral blood CFU-GM. Replacement of SS by bovine fetal serum resulted in suboptimal growth of ovine CFU-GM.

Animals↗
PubMed1982

Effects Of NO2 on immune responses in pulmonary lymph of sheep.

Sheep in which the efferent duct of the caudal mediastinal lymph node was cannulated were exposed to 5 ppm No2, 1.5 h/d for 10 or 11 d. Immune responses were assessed by measuring the daily output of hemolytic plaque-forming cells (PFC) in pulmonary lymph, following intrabronchial immunization with horse red blood cells (HRBC) and phytohemagglutinin- (PHA) induced transformation of blood and pulmonary lymph lymphocytes. Sheep immunized 2 d after termination of NO2 exposure had reduced outputs of PFC as compared to those seen in sheep challenged 4 d after NO2 exposure. Animals immunized 4 d after NO2 exposure had outputs similar to those of air control sheep. A reduction of 38-87% in the transformation index of both blood and pulmonary lymph lymphocytes was observed in sheep exposed to NO2. These results suggest that intermittent, short-term exposure to 5 ppm NO2 may temporarily alter pulmonary immune responsiveness.

Animals↗
PubMed1981

Evidence for two forms of reverse transcriptase in human placenta of a patient with breast cancer. Purification and biochemical characterization of the enzymes.

Two DNA polymerases with properties of viral RNA-directed DNA polymerase were found in the placenta of a patient with breast cancer. Both enzyme activities were purified by column-chromatographic procedures or by preparative isoelectric focusing. The most distinguishing feature of the two enzymes is their specificity to transcribe (rA)n . (dT)12 or (rC)n . (dG)18. The two enzymes differ with respect to their elution profiles from the phosphocellulose column, isoelectric point, molecular weight, bivalent-cation requirements and thermal stability. Serological analysis of the (rA)n . (dT)12-activated enzyme showed that this enzyme is immunologically not related to DNA polymerase-gamma, or to any of the reverse transcriptases purified from retroviruses of avian, murine and subprimate origin. However, the activity of this enzyme was neutralized by antibodies to reverse transcriptase purified from human spleen of a patient with myelofibrosis [Chandra & Steel (1977) Biochem. J. 167, 513-524]. Attempts to purify reverse transcriptase of normal human placenta were repeatedly unsuccessful. Once the crude homogenate of normal placenta was freed from endogenous nucleic acids, no (rC)n . (dG)18-dependent activity cold be detected.U

Breast Neoplasms↗
PubMed1981

The predictability of labor outcome from a comparison of birth weight and x-ray pelvimetry.

The value of x-ray pelvimetry in labor has recently been questioned by many, although few morphometric data on the fetopelvic relationship have been presented. Fifty-one women who had dysfunctional labor, in whom both x-ray pelvimetry and oxytocin were used during clinical management, were studied. Twenty-seven were delivered by cesarean section, while 24 were delivered vaginally. Regression equations were developed for multiple pelvic indices versus birth weight. The analysis revealed no differences between the vaginal group and the cesarean section group. The design of this study suggests that the variables of pelvic measurements and birth weight do not provide a predictive tool for delivery outcome. The approximately 15% margin of dimensional differences between a successful outcome and a failed outcome is too small to be detected by current diagnostic methods.

Adult↗
PubMed1981

A study of antitemplate inhibition of mammalian, bacterial and viral DNA polymerases by 2- and 2'-substituted derivatives of polyadenylic acid.

In the present study, effects of various 2- and 2'-substituted polyadenylic acid analogs on eukaryotic, bacterial and viral DNA polymerases were investigated. The polymer containing 2'-deoxy-2'fluoroadenosine, (dAfl)n, showed a concentration dependent stimulation of (rA)n . (dT)12-catalyzed reverse transcriptase reaction from Rauscher Leukemia Virus (RLV). A similar stimulation of the (rA)n . (dT)12-catalyzed DNA polymerase-gamma reaction was also observed. However, the (rC)n . (dG)12-dependent reverse transcriptase activity was inhibited by (dAfl). The DNA polymerase-beta activity catalyzed by (dA)n . (dT)12 was also inhibited by (dAfl)n. The reported data indicate that (dAfl)n closely resembles (rA)n as a functional template. In contrast, the 2-substituted derivatives, poly(2-methylthioadenylic acid) and poly(2-ethylthioadenylic acid), are not able to discriminate between the reactions catalyzed by different templates. For example, both derivatives inhibit (rA)n . (dT)12- and (rC)n . (dG)12-catalyzed reverse transcriptase reaction to the same extent; though the methylthio derivative is a much better inhibitor than the ethylthio analog. The DNA polymerase-alpha was less sensitive to these inhibitors; whereas the bacterial DNA polymerase (Kornberg enzyme; DNA polymerase I) was completely resistant to the action of all the derivatives used in this study.

Animals↗
PubMed1980

An in vivo-in vitro short term carcinogenicity test using rat peritoneal cells.

A new short-term mammalian carcinogenicity test system is presented in which an in vivo application in rats is followed after 2 weeks by an in vitro culture of the peritoneal cells. One week of culture was sufficient to induce colony growth in soft agar in some cultures of the dimethylnitrosamine (DMNA)-treated, but not in those of control, rats. The results proved to be reproducible and dose-related. Suspended colony growth was not observed in cultures of control rats stimulated successively by the 2 mitogens: thioglycollate and Al(OH)3. The incidence of rats showing transformed colonies in their cultures after a single DMNA dose of 20 mg/kg was nearly double that reported for rats developing tumors after a higher single dose of 30 mg/kg DMNA. More recent experiments have shown that whereas the carcinogen benzo[a]pyrene was positive, its non-carcinogenic analog benzo[e]pyrene was negative; both applied at a single oral dose of 15 mg/kg. A similar result was observed with the acetylaminofluorene (AAF) analogs: 2-AAF and 4-AAF, where the former, a carcinogen, proved positive and the latter, a non-carcinogen, negative. Both analogs were applied at a single oral dose of 50 mg/kg. 2-AAF was also positive at a dose of 25 mg/kg corresponding to 2.5% of the highest tolerable dose of this carcinogen. These results suggest a high structure-related specificity of our test system. Many more similar tests with carcinogen/non-carcinogen analogs will be needed however, before this specificity can be sufficiently established.

2-Acetylaminofluorene↗
PubMed1980

RNA-dependent DNA polymerase activity in ocular granulocytic sarcoma associated to acute myelomonocytic leukemia in Turkish children. Biochemical and immunological characterization of the enzyme.

The present study describes the separation and purification of a reverse transciptiase from an orbital tumor of a patient with acute myelomonocytic leukemia. Specific reaction conditions with respect to ionic requirements and template-primers are reported. The purified enzyme was able to transcribe (rA)n . (dT)12, (rC)n . (dG)12, (OMeC)n . (dg)12 and the 70 S RNA from R(Mu)LV. Serological studies that the reverase transcriptase is antigenically related to reverse transcriptase from the type C woolly monkey virus-gibbon ape leukemia virus group.

Animals↗