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Biomedical subjects

S Datta

Publications and source records attributed to S Datta.

At least 325 records · Page 18Linked to original sources

Differential sensitivities of mammalian nerve fibers during pregnancy.

The onset of conduction blockade in the vagus nerve of pregnant and nonpregnant rabbits was studied utilizing an in vitro sheath nerve preparation. The time required for 50% depression of the action potential (AP) of A, B, and C vagal fibers from five pregnant and six nonpregnant animals was determined after the application of bupivacaine (0.35 mM). The onset of conduction block occurred in 6.7-12.1 min in the A, B, and C fibers from pregnant animals compared to onset times of 17.9-31.6 min in nerves taken from nonpregnant rabbits. The difference in onset time for each type of nerve fiber from pregnant and nonpregnant animals was highly significant. The results suggest either an increased sensitivity of nerve fibers from pregnant animals to bupivacaine or an enhanced diffusion of the bupivacaine to the membrane receptor site. Mechanical factors are clearly not responsible for the observed results. Hormonal factors may play a role in the decreased anesthetic latency, because progesterone levels were significantly higher in the pregnant animals.

Action Potentials↗

Comparison of the maternal and neonatal effects of halothane, enflurane, and isoflurane for cesarean delivery.

The maternal and neonatal effects of 50% O2-50% N2O alone and 50% O2-50% N2O combined with 0.5% halothane, 1.0% enflurane, or 0.75% isoflurane were studied in 42 healthy parturients undergoing general anesthesia for elective primary or repeat cesarean delivery at term. All patients received thiopental and succinylcholine for induction and were intubated and ventilated with a tidal volume of 10 ml/kg at a rate of 10 breaths/min. Two of 12 (17%) patients given O2-N2O alone had recall; none who received a potent inhalation agent had any recall. Blood loss was similar in all four groups. There were no significant differences between groups in induction-to-delivery and uterine incision-to-delivery intervals, the frequency of Apgar scores less than 7 at 1 and 5 min, maternal and fetal blood-gas tensions, acid-base balance, lactate values, and early neonatal neurobehavioral scores at 2-4 h. It is concluded that analgesic concentrations of halothane, enflurane, and isoflurane can be safely added to 50% O2-50% N2O to prevent maternal awareness during general anesthesia for cesarean delivery while maintaining normal maternal and neonatal conditions.

Anesthesia, Inhalation↗

Antimicrobial, insect sterilizing and ovicidal activity of some oxo-vanadium(IV) and oxo-vanadium(V) complexes.

Twenty-three newly synthesized mixed-ligand complexes of oxo-vanadium(IV) and oxo-vanadium(V) were studied for antimicrobial activity. Eight of these complexes were found to have microbicidal properties. The complexes [NH4][VO(gl)2]H2O (gl-H2 = glycolic acid) and [VO(ACOAP)(acac-H)]H20 (ACOAP-H2=Schiff base of acetylacetone and orthoaminophenol, acac-H=acetyl-acetone) show broad bactericidal spectra, while the complexes [VO(ACSAM)2]OH (ACSAM-H = Schiff base of acetylacetone and sulphanilamide) and [VO(CSSAM-H)2]H2O (CSSAM-H =Schiff base of 3-carboxy salicylaldehyde and sulphanilamide) possess pronounced antidermatophytic properties. The latter is inhibitory to plant pathogenic fungi as well. Plant tumour producing Agrobacterium tumefaciens is effectively inhibited in vitro by the complex [VO(ACTSC-Na)(acac)]H2O (ACTSC-H2 = condensation product of acetylacetone and thiosemicarbazide). Minimum inhibitory concentrations of all the active complexes are within the values of 0.125-2.00 mg/ml. Out of the 7 active complexes tested for 50% inhibition of conidial germination of Helminthosporium oryzae, a rice plant pathogen, only 1 complex, viz. [VO(acac) (ACACAACD)] (ACACAACD(H)NH4 equal Schiff base of acetylacetone and ammonium 2-amino-1-cyclopentene-1-dithiocarboxylate) shows a positive result. The effective concentration is 0.55 mg/ml. Three vanadium complexes were tested for insect sterilant and ovicidal properties on the red cotton bug, Dysdercus koenigi. The complex [VO(HASA-Na) (acac)]H2O (HASA-H2 = Schiff base of orthohydroxyacetophenone and anthr anilic acid) was found to be a suitable male sterilant.

Animals↗

Hypermagnesaemia and anaesthetic management.

The anaesthetic management of a pre-eclamptic parturient who was treated with high doses of magnesium sulphate and who developed hypermagnesaemia before delivery by Caesarean Section, is presented. The pharmacology of magnesium, particularly its effects at the neuromuscular junction, and clinical considerations of magnesium administration are discussed.

Adult↗

Spinal anaesthesia for Caesarean section. The influence of hypotension on neonatal outcome.

The effect upon the neonate of a short period of maternal hypotension sustained during the initiation of spinal analgesia for Caesarean section was studied. Babies born to mothers with hypotension were significantly more acidotic than controls although acid-base levels were still within normal limits. Neurobehavioural studies were found to be normal in both groups at 4 and 24 hours. It was concluded that a short period (less than 2 minutes) of hypotension was not harmful to the neonate.

Acid-Base Equilibrium↗

Dissociation of plasma and cerebrospinal fluid beta-endorphin-like immunoactivity levels during pregnancy and parturition.

The association between central (cerebrospinal fluid [CSF]) and peripheral (plasma) levels of beta-endorphin-like immunoactivity (beta-ELI) in nonpregnant women (n = 8) and pregnant women (a) at 16 to 20 weeks of gestation (n = 6), (b) at term (n = 21), and (c) in labor (n = 15) was investigated. Umbilical arterial (n = 11) and venous (n = 11) samples were also obtained. In agreement with previous investigations, it was found that plasma levels of beta-ELI increased during labor (mean +/- SEM: nonpregnant women, 63.5 +/- 18.2; pregnant women at term, 64.0 +/- 12.2; women in labor, 110.8 +/- 30.3 pg/ml), and that levels of umbilical arterial plasma of beta-ELI exceeded those in umbilical venous plasma (132.5 +/- 34.0 versus 68.2 +/- 22.2). However, CSF levels of beta ELI did not change over the course of pregnancy or during labor (nonpregnant women, 36.5 +/- 15.8; pregnant women at 16 to 20 weeks of gestation, 60.1 +/- 10.3; pregnant women at term, 57.5 +/- 8.4; women in labor 48.5 +/- 8.3 pg/ml). This evidence that plasma and CSF levels of beta-ELI are dissociated during labor calls into question inferences regarding behavioral changes during parturition based on plasma beta-ELI measurements.

Endorphins↗

Some genetic markers in tribals of Eastern India.

A total of 204 members belonging to two ethnologically distinct tribal groups in the same area, the Santal and the Bhumij, from the Midnapore district of West Bengal have been tested for polymorphisms of serum proteins, enzymes and haemoglobin. Low chi 2 value indicates the absence of any significant genetical difference between these two tribes, in respect of their total protein patterns and Hb, Tf, Hp, Lp, LDH, ABO and Rh systems. An interesting observation was the presence of an aberrant transferrin type. A single case of phenylketonuria showed low elevation of phenylalanine.

Adult↗

Acid-base status of diabetic mothers and their infants following spinal anesthesia for cesarean section.

Acid-base status and Apgar scores were evaluated in 10 rigidly controlled insulin-dependent diabetic mothers and 10 healthy nondiabetic control women having spinal anesthesia for cesarean section. Dextrose-free intravenous solutions were used for volume expansion before induction of anesthesia, and hypotension was prevented in all cases by prompt treatment with ephedrine. There were no significant differences in the acid-base values between the diabetic and nondiabetic mothers and the infants of the diabetic and control group. Apgar scores were also similar in the two groups. If maternal diabetes is well controlled, if dextrose-containing solutions are not used for maternal intravascular volume expansion before delivery, and if maternal hypotension is avoided, spinal anesthesia can be used safely for diabetic mothers having cesarean section.

Acid-Base Equilibrium↗

Buffalo alpha S1-casein; its terminal residues and amino acid composition.

Buffalo alpha S1-casein was treated with carboxypeptidase-A to determine the C-terminal amino acid residue, which was - leucine-tryptophan. The Sakaguchi reagent was used to confirm arginine as the N-terminal amino acid. The colored p-phenylazophenyl thiohydantoins of tryptophan and arginine released from C- and N-terminals respectively were quantitatively estimated and from this molecular weights of buffalo alpha S1 casein were calculated and found to be 26,300 and 26,100 respectively.

Amino Acids↗

Antimicrobial, insect sterilizing and ovicidal activity of some cobalt(II) and cobalt(III) complexes.

Twenty-one mixed-ligand complexes of cobalt(II) and cobalt(III) have been screened for their antimicrobial, insect sterilizing and ovicidal activities. Three of these cobalt(III) complexes exhibit broad antimicrobial spectra, including against human bacterial pathogens, dermatophytes and plant pathogenic fungi, while one exhibits feeble activity against a human pathogenic bacterium. These results have been compared with the activity of the corresponding cobalt(II) complexes, which have been found to be inactive, while the free ligands show reduced activity compared with the cobalt(III) complexes. Change in biological activity induced by a particular complex appears to be dependent on the composition of the first co-ordination sphere. Two of these complexes showed 50% inhibition of the conidial germination of Helminthosporium oryzae and Alternaria triticina. These results indicate their potential for use against human and plant pathogenic microbes. Minimum inhibitory concentrations of the cobalt(III) complexes were determined. Three of these cobalt(III) complexes have been tested for insect sterilizing and ovicidal activities on Dysdercus koenigi F. Positive sterilizing and ovicidal actions of [Co(BSOP)(NH3)2]NO3 (where BSOP-H2 is the Schiff base derived from salicylaldehyde and orthophenylene-diamine) were obtained. Possible mechanism(s) of all these activities are discussed qualitatively.

Animals↗