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Biomedical subjects

A C Roy

Publications and source records attributed to A C Roy.

At least 55 records · Page 3Linked to original sources
PubMed1992

A new technique for detecting oxytocinase activity in electrophoresis gels.

A sensitive staining method for the detection of oxytocinase (EC 3.4.11.3) activity in electrophoresis gels has been described. The method is based on the enzymatic release of p-nitroaniline (PNA) from two specific synthetic oxytocinase substrates, S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN), respectively. The PNA is then diazotized with sodium nitrite and subsequently coupled to a chromogen, N-(1-naphthyl)-ethylenediamine dihydrochloride (NED) to produce a deep pink/magenta colored azo-dye at the site of oxytocinase activity.

Aniline Compounds↗
PubMed1992

Biosynthesis of prostaglandins by human spermatozoa in vitro and their role in acrosome reaction and fertilization.

Five homogenates of human sperm cells were separately incubated with [14C]arachidonic acid in the presence of reduced glutathione, L-tryptophan, and haematin as cofactors. The cyclooxygenase products of arachidonic acid metabolism were extracted, separated, and measured for their radioactivity. The rate of formation of prostaglandin (PG)D2, PGE2, PGF2 alpha, 6-keto PGF1 alpha, and thromboxane (TX)B2 were 18.0 +/- 1.11, 10.9 +/- 0.68, 5.8 +/- 0.21, 3.9 +/- 0.13 and 6.6 +/- 0.52 pmol/10(6) cells/min, respectively. These results are discussed in relation to the hypothesis that cyclooxygenase metabolites of certain polyunsaturated fatty acids play an important part in the sperm acrosome reaction and fertilization.

Acrosome↗
PubMed1992

Genetic study of five populations of Bihar, India.

Four-hundred fifty-nine people, including 106 Santals, 43 Bhuiyas, 107 Sakaldipi Brahmins, 108 Chamars, and 95 Ansari Muslims, of the Giridhi district of Bihar have been tested for transferrin, group-specific component, phosphoglucomutase subtypes, and glyoxalase-I, 6-phosphogluconate dehydrogenase, and adenylate kinase types. Genetic distance estimates by both dendrogram and principal component methods for these 5 populations and the Oraons on the basis of 19 alleles at 6 polymorphic loci indicate 2 major clusters: Brahmins and Muslims, the latter of which is composed of two subclusters (Santals and Bhuiyas, and Oraons and Chamars). The Santal and Bhuiya tribes both speak Mundari, whereas the Oraons speak a Dravidian language. The Chamars, although low-caste Hindus, seem to have a non-Europoid origin, as do the Oraons.

Adenylate Kinase↗
PubMed1991

Influence of serum paraoxonase polymorphism on serum lipids and apolipoproteins.

One hundred and sixty-three healthy Chinese subjects of both sexes were studied for serum paraoxonase (PON) polymorphism, and levels of lipids and apolipoproteins in order to examine effects of PON alleles on these parameters. The level of serum triglyceride was significantly higher in high activity allele (PON*B) compared with that in low activity allele (PON*A) in both sexes (P less than 0.01). The subjects with PON A had significantly higher LDL cholesterol (P less than 0.05) and lower Apo A-II and ApoB levels. The influence of serum paraoxonase on serum lipids was estimated further by Spearman's rank correlation. In the males, there was a significant negative correlation of serum paraoxonase activity with total (P less than 0.05) and LDL (P less than 0.01) cholesterol levels, and positive correlation with HDL cholesterol and Apo A-II levels (P less than 0.05). Serum paraoxonase activity had a high positive correlation with serum triglyceride levels in both sexes (P less than 0.001). Serum ApoB level had a positive correlation with the enzyme activity only in females (P less than 0.01). The allelic effect of PON on these parameters was studied by multiple regression analysis. The high activity allele (PON*B) was associated with higher serum triglyceride level (P less than 0.001) and ApoB (P less than 0.001), while it had lowering influence on total cholesterol (P less than 0.05) and LDL cholesterol (P less than 0.005) in men. The average allelic effect of PON was found to be about 22% for serum triglycerides, 11% for LDL cholesterol, 14% for Apo A-II and 19% for Apo B in the present study. This study suggests a possible significant role of serum paraoxonase alleles in the metabolism of serum lipids and apolipoproteins.

Adult↗
PubMed1991

Serum paraoxonase polymorphism in three populations of southeast Asia.

Serum paraoxonase hydrolyzes paraoxon, the principal metabolite of the insecticide parathion. Serum paraoxonase is polymorphic and controlled by two codominant alleles - PON*A and PON*B representing low and high activity, respectively. Three populations of southeast Asia comprising 194 Chinese, 159 Filipinos and 73 Dravidian Indians were investigated for serum paraoxonase polymorphism. The frequency of PON*B was found to be 0.14 in the Chinese, 0.04 in the Filipinos and 0.18 in Dravidian Indians. The distribution of the PON phenotypes was at Hardy-Weinberg equilibrium in all the three populations studied.

Aryldialkylphosphatase↗
PubMed1991

Pharmacology of parturition.

Uterine contractions in labour are influenced by endogenous substances such as oestrogens, progesterone, cortisol, oxytocin, prostaglandins, relaxin, adrenergic and cholinergic secretions, cyclic nucleotides and calcium ions. Effects of progesterone and oestrogens are complimentary as well as antagonistic to each other. They regulate formation of gap junctions, influx of calcium ions, synthesis of oxytocin, adrenergic receptors and of prostaglandins and cyclic nucleotides. Cortisol shares a role in a more complex endocrine trigger but is ineffective alone in the initiation of human labour. Adrenaline inhibits and noradrenaline promotes uterine contractions. Cholinergic stimulation increases cyclic GMP promoting uterine contractions. Calcium ions play a key role in uterine contractility. Oxytocin, prostaglandins E and F are powerful stimulants of uterine contractions. Prostaglandins stimulate pregnant uterus from early gestation unlike oxytocin which has little effect in the first and second trimester. They are extensively used for initiating labour and to arrest intractable atonic postpartum haemorrhage. In experiments and in vivo, their effects are modulated by other hormones and substances. With discovery of new drugs, knowledge of how they act on the uterus becomes important. The pharmacology of parturition that may help to understand the interaction of various agents on the pregnant uterus has been discussed.

Calcium↗
PubMed1990

Chemical evolution and the origin of life: cumulative keyword subject index 1970-1986.

This cumulative subject index encompasses the subject indexes of the bibliographies on Chemical Evolution and the Origin of Life that were first published in 1970 and have continued through publication of the 1986 bibliography supplement. Early bibliographies focused on experimental and theoretical material dealing directly with the concepts of chemical evolution and the origin of life, excluding the broader areas of exobiology, biological evolution, and geochemistry. In recent years, these broader subject areas have also been incorporated as they appear in literature searches relating to chemical evolution and the origin of life, although direct attempts have not been made to compile all of the citations in these broad areas. The keyword subject indexes have also undergone an analogous change in scope. Compilers of earlier bibliographies used the most specific term available in producing the subject index. Compilers of recent bibliographies have used a number of broad terms relating to the overall subject content of each citation and specific terms where appropriate. The subject indexes of these 17 bibliographies have, in general, been cumulatively compiled exactly as they originally appeared. However, some changes have been made in an attempt to correct errors, combine terms, and provide more meaningful terms.

Exobiology↗
PubMed1990

Oxytocinase activity in human spermatozoa and its possible role in fertilization.

Human spermatozoa were extracted with 1% Triton X-100 and analyzed for oxytocinase (E.C. 3.4.11.3) activity by means of two synthetic peptides. S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN), separately as substrates. The specific activity (mean +/- SD) of this proteolytic enzyme at Vmax in eight different extracts was 0.150 +/- 0.072 and 1.392 +/- 0.602 mIU/10(6) cells using BCN and LN, respectively. The enzyme showed optimal activity at pH 7.2 when BCN was the substrate, and at pH 7.4 with LN as the substrate. Spermatozoal oxytocinase activity may be involved directly or indirectly in the reproductive mechanisms leading to sperm acrosome reaction and fertilization.

Adult↗
PubMed1990

Lack of correlation of selenium level in human semen with sperm count/motility.

Considering the importance of selenium (Se) in male fertility, its concentration was measured in 211 semen samples from 211 normozoospermic, oligozoospermic, asthenozoospermic, and azoospermic men using the hydride generation atomic absorption spectrophotometry. No significant correlation of any kind existed between Se level in the seminal plasma and sperm count or motility. In view of the known poor correlation of these two frequently used semen parameters with the incidence of pregnancy, the assessment of the fertilizing potential of normozoospermic ejaculates with low Se levels is warranted.

Adult↗
PubMed1989

Evidence for several fold more activity of NAD+-dependent uterine prostaglandin 15-hydroxydehydrogenase in transsexual than in non-transsexual women.

The activity of NAD+-dependent PGDH was measured in the cytosolic fractions (100,000 x g) of uterine tissues obtained from transsexual, pregnant and non-pregnant women. The specific activity (mean +/- SD) of the enzyme at maximum velocity of the enzyme reaction in these three groups of women was 5.5 +/- 2.30, 0.53 +/- 0.27 and 0.54 +/- 0.25 mU/mg protein respectively using PGE2 as substrate, and with PGF2 alpha as substrate the respective values were 5.48 +/- 2.80, 0.49 +/- 0.41 and 0.51 +/- 0.30 mU/mg protein. These data suggest that, with either substrate, the uterine enzyme activity in the transsexuals was about 10-fold greater than in pregnant and non-pregnant women (p less than 0.001). However, the Km values of the enzyme for both PGE2 and PGF2 alpha were similar in all three groups, indicating the presence of same enzyme in the uterus of transsexual, pregnant and non-pregnant women. We speculate that PGDH activity was raised in the uterus of transsexual women because of the prolonged androgen therapy they received for the management of female-to-male transsexualism.

Adult↗
PubMed1989

Prostaglandin 15-hydroxydehydrogenase activity in human penile corpora cavernosa and its significance in prostaglandin-mediated penile erection.

Prostaglandins may be involved in human penile erection and erectile failure. To evaluate the possible role of prostaglandin metabolism in the penile tissue, the activity of nicotinamide adenine dinucleotide-dependent prostaglandin 15-hydroxydehydrogenase was assayed in the corpora cavernosa of the human penis. Km values (mean +/- SD) of the enzyme for PGE1, PGE2 and PGF2 alpha were 60.1 +/- 4.2, 17.7 +/- 1.5 and 16.1 +/- 1.2 microM respectively; Vmax values (mean +/- SD) were 0.219 +/- 0.062, 0.510 +/- 0.012 and 0.424 +/- 0.007 nmol/min/mg protein respectively. The implications of these findings in the erectile process are discussed.

Humans↗
PubMed1989

Amniotic fluid selenium status in pre-eclampsia.

Selenium levels were measured in amniotic fluid samples obtained from 60 normal pregnant and 40 pre-eclamptic women closely matched for age and gestation using the hydride generation technique coupled with atomic absorption spectroscopy. The mean +/- SD levels in the normal and pre-eclamptic groups were 6.8 +/- 3.7 and 6.7 +/- 2.2 ng/ml, respectively. The difference in the values of amniotic fluid selenium between these two groups of patients was not statistically significant (p greater than 0.5).

Adult↗
PubMed1989

Selenium status in pregnancy: studies in amniotic fluid from normal pregnant women.

Selenium concentrations were determined in amniotic fluid samples obtained from 111 healthy normal pregnant women (median age, 27.5 years) between 12 and 42 weeks of gestation using hydride generation technique coupled with atomic absorption spectroscopy. There was a gradual decrease in the amniotic fluid selenium concentration with the progress of pregnancy. The negative correlation between the gestational age and amniotic fluid selenium concentration was highly significant (p less than 0.001). The implications of these findings in normal pregnancy are discussed.

Amniotic Fluid↗
PubMed1989

Fractionation and characterization of oxytocinases in human semen.

Two isoenzymes of oxytocinase activity were fractionated from human seminal plasma by acrylamide-agarose gel chromatography and partly characterized using S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN) separately as substrates. These isoenzymes appeared to be metallo-aminopeptidases with different elution volumes (90 ml and 150 ml), apparent molecular weights (unknown value and 300,000) and pH optima (6.8 and 7.0 with BCN and 7.2 and 7.4 with LN), but with similar substrate affinity and thermal sensitivity, and susceptibility to EDTA, divalent metal ions, L-methionine, polypeptide hormones and prostaglandins. A comparison of the enzymic properties with pregnancy-associated oxytocinases suggests that seminal oxytocinases are related more closely to amniotic fluid isoenzymes than to pregnancy serum, placental and uterine isoenzymes.

Aminopeptidases↗
PubMed1987

Human follicular fluid levels of calcium, copper and zinc.

Human follicular fluid was collected under laparoscopic vision from 33 follicles in patients stimulated with clomiphene-human menopausal gonadotrophin in an IVF programme. Thirty-one oocytes were obtained from 26 follicles from which clear follicular fluid was obtained, and 16 oocytes fertilized and cleaved. The follicular fluid was analysed for calcium, copper and zinc using atomic absorption spectroscopy. The mean levels of calcium, copper and zinc were 86.9 +/- 11.6, 1.16 +/- 0.29, and 0.72 +/- 0.12 micrograms/ml, respectively. Their levels were not significantly different in the follicular fluid collected from follicles of different sizes, with or without oocyte, and follicles with oocytes that were fertilized and were unable to be fertilized. Therefore, the concentrations of these elements do not seem to reflect oocyte status or maturity.

Calcium↗
PubMed1986

Oxytocinase activity in human amniotic fluid and its relationship to gestational age.

Oxytocinase (EC 3.4.11.3) activity in amniotic fluid samples obtained from 200 normal pregnant women (mean age, 28 years) between 14 and 40 weeks of gestation and during active labor was assayed using S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN) separately as substrates. With both substrates, amniotic fluid oxytocinase activity correlated inversely with gestational age; the level of the enzyme, which was highest in early pregnancy, decreased exponentially to a minimum near term and during labor. However, whether oxytocinase activity in the amniotic fluid is of any significance for the maintenance and/or termination of pregnancy remains to be established.

Aminopeptidases↗
PubMed1985

Prostaglandins, not cyclic GMP, inhibit oxytocinase isoenzymes from human amniotic fluid in vitro.

Two isoenzymes of oxytocinase (EC 3.4.11.3) activity were fractionated from human amniotic fluid samples between the 14th and 22nd weeks of gestation by Ultrogel acrylamide-agarose gel filtration and partially characterized. The isoenzymes were competitively inhibited by PGE1, PGE2 and PGF2 alpha more at pH 6.2 than at pH 6.8, whereas cyclic GMP (cGMP) and its 8-bromo derivative had no effect at either pH. The implications of these findings are discussed and it is suggested that since the activity of amniotic fluid oxytocinases is very low or minimal at or near term, inhibition of these by prostaglandins may not have physiological significance in the initiation of human parturition.

Aminopeptidases↗