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Biomedical subjects

S Ray

Publications and source records attributed to S Ray.

At least 91 records · Page 5Linked to original sources
PubMed1986

Studies in antifertility agents. 50. Stereoselective binding of d- and l-centchromans to estrogen receptors and their antifertility activity.

Centchroman [dl-3,4-trans-2,2-dimethyl-3-phenyl-4-[p-(beta-pyrrolidinoethoxy)phenyl] - 7-methoxychroman hydrochloride], an antifertility agent under clinical evaluation, has been resolved into its optical enantiomers. The cytosol estrogen receptor binding affinity and estrogenic, antiestrogenic and antiimplantation activities of the two enantiomers have been determined. The enantiomers display a 7-fold difference in receptor affinity, and a corresponding difference in stimulation of the uterine growth and antiimplantation activity was observed in rats.

Animals↗
PubMed1986

Stimulation of human neuroblastoma DNA polymerase alpha and primase activities by a protein factor isolated from rat liver chromatin.

Nuclear protein factor type 1 (NPF-1) that simulates IMR-32 primase-associated DNA polymerase alpha 1 and alpha 2 activities has been purified from a high-salt extract of liver chromatin from 6-month-old rats. The final purified factor lacks DNA polymerase alpha, RNA polymerase, and DNA-unwinding or topoisomerase type I activities. The stimulatory activity is destroyed by trypsin (60 min at 37 degrees C), DNase II (60 min at 37 degrees C), and heat treatment (2 min at 68 degrees C). The 125I-labeled NPF-1 does not bind to activated calf thymus DNA or poly(dC). However, it forms a ternary complex with DNA in the presence of DNA polymerase alpha-primase complex (alpha 1 and alpha 2). The ternary complex sediments on sucrose density gradient as a heavier band (11S). The NPF-1 also stimulates (2.5-fold) primase-catalyzed incorporation of GMP and dGMP from the corresponding triphosphates on poly(dC) template even in the presence of a high concentration of alpha-amanitin (400 micrograms/ml). The labeled duplex containing the poly(dC) template, [32P]-GTP, and [3H]dGTP loses 80% of the 32P label and 70% of the 3H label after treatment with 0.3 M KOH and DNase I, respectively. The products were isolated from reaction mixtures incubated with and without NPF-1 and subjected to alkaline sucrose-density-gradient sedimentation analysis. The results suggest that the rate of synthesis of DNA short chains is increased in the presence of NPF-1 without a concomitant increase in the chain length of the newly synthesized products.

Animals↗
PubMed1986

Electrical conduction in bone in frequency range 0.4-1.3 GHz.

Dielectric permittivity and conductivity of bone in different physiological conditions and collagen, a major component of bone are measured in the frequency range 400-1300 MHz using a Network analyzer. The dielectric dispersion observed in each cases are explained in terms of the relaxation of 'bound water' in this frequency range. The relaxation frequency as well as distribution parameter are computed in each case, under certain simplifying conditions, hydration as well as static dielectric permittivity of bound water attached with bone in different physiological conditions and collagen are also calculated. The effect of ultraviolet light irradiation on the dielectric properties of bone in this frequency range is also examined. The change in dielectric properties due to radiation is attributed to the breakage of hydrogen bonds in the ring structure. A consistent physical model in line with other data is presented.

Animals↗
PubMed1986

Pelvic dysplasia associated with arthrogrypotic changes in the lower extremities. A new syndrome.

Two sisters exhibit arthrogrypotic changes in the lower extremities associated with a previously undescribed pelvic dysplasia. The pelvic dysplasia is characterized by: severe abnormalities of ossification with markedly widened triradiate cartilages; irregular, notched acetabulae; marked hypoplasia of the ilia; notching of the iliac wings; and delayed ossification of the capital femoral ossific nucleus. The elder girl has bilateral clubfeet, as well as flexion contractures of both knees. The younger girl has a right talipes equinovarus and left hip dislocation. Autosomal recessive inheritance is suggested. This distinctive syndrome should be considered in the differential diagnosis of the patient with arthrogryposis.

Arthrogryposis↗
PubMed1986

Articular sporotrichosis.

Sporotrichosis is a fungal disease caused by Sporothrix schenckii, which is seen worldwide. Infection usually involves cutaneous and subcutaneous tissues. Articular involvement is rare. A 29-year-old man with ankle sporotrichosis is reported to demonstrate the differential diagnosis and treatment.

Adult↗
PubMed1985

L-Threonine dehydrogenase from goat liver. Feedback inhibition by methylglyoxal.

L-Threonine dehydrogenase, which forms aminoacetone from L-threonine and NAD, has been extensively purified from goat liver. A feedback inhibition of this enzyme has been observed with methylglyoxal. Kinetic data and other experiments indicate that methylglyoxal acts at a site other than the active site of the enzyme. The enzyme contains a single subunit of Mr 89,000. The apparent Km values of the enzyme for L-threonine and NAD were found to be 5.5 and 1 mM, respectively.

Alcohol Oxidoreductases↗
PubMed1984

Cis isomer of centchroman--a selective ligand for the microsomal antiestrogen binding site.

Several compounds structurally related to the triarylethylene antiestrogens, but possessing weak estrogen receptor affinities, were assessed for their ability to interact with the microsomal antiestrogen binding site. While all the compounds tested did interact with this site their relative affinities were somewhat lower than that of tamoxifen. One of these, viz., the cis isomer of centchroman, has however emerged as a selective ligand for the antiestrogen binding site since its estrogen receptor affinity is nearly 50,000 times lower on a relative scale.

Animals↗
PubMed1984

Purification and partial characterization of a methylglyoxal reductase from goat liver.

An enzyme which catalyzes the reduction of methylglyoxal to lactaldehyde has been isolated and purified from goat liver to apparent homogeneity. NADH was found to be a better substrate than NADPH for methylglyoxal reduction. Stoichiometrically equivalent amounts of lactaldehyde and NAD are formed from methylglyoxal and NADH. Enzyme activity was located only in the soluble supernatant fractions of liver cells. Of the various carbonyl compounds tested, methylglyoxal was found to be the best substrate. The pH optimum of the enzyme was found to be 6.5, and Km for methylglyoxal was 0.4 mM. The molecular weight of the enzyme was found to be 89000 by gel filtration on a Sephadex G-200 column. Electrophoresis on sodium dodecyl sulfate-polyacrylamide gel revealed that the enzyme is composed of two subunits. The enzyme is highly sensitive to sulfhydryl group reagents. The inactivation by p-chloromercuribenzoate could be substantially protected by methylglyoxal in combination with NADH, indicating a possible involvement of one or more sulfhydryl group(s) at the active site of the enzyme.

Alcohol Oxidoreductases↗
PubMed1984

Oxidation of lactaldehyde by cytosolic aldehyde dehydrogenase and inhibition of cytosolic and mitochondrial aldehyde dehydrogenase by metabolites.

An enzyme fraction which oxidizes lactaldehyde to lactic acid has been purified from goat liver. This enzyme was found to be identical with the cytosolic aldehyde dehydrogenase. Lactaldehyde was found to be primarily oxidized by this enzyme. Almost 90% of the total lactaldehyde-oxidizing activity is located in the cytosol. Methylglyoxal and glyceraldehyde 3-phosphate were found to be strong competitive inhibitors of this enzyme. Aldehyde dehydrogenase from goat liver mitochondria has also been partially purified and found to be strongly inhibited by these metabolites. The inhibitory effects of these metabolites on both these enzymes are highly pH dependent. The inhibitory effects of both the metabolites have been found to be stronger for the cytosolic enzyme at pH values higher than the physiological pH. For the mitochondrial enzyme, the inhibition with methylglyoxal was more pronounced at higher pH values, whereas stronger inhibition was observed with glyceraldehyde 3-phosphate at physiological pH.

Aldehyde Dehydrogenase↗
PubMed1984

Orthopaedic problems associated with survival in campomelic dysplasia.

In the early part of this century sporadic reports of campomelic dysplasia appeared in the literature, along with reports of other entities, under the term "congenital bowing of the long bones." In 1970 Spranger et al. considered campomelic dysplasia a distinct entity. The terms "camptomelic" and "campomelic" have been used interchangeably in the literature since that time. The patient in the present report is a 6 1/2-year-old white girl with classic long-limbed campomelic dysplasia. The patient has had severe respiratory problems throughout her life. As an infant she was treated by a Pavlik harness for subluxation of the hips. She later required two cervical and two thoracic posterior spinal fusions, as well as release of complex foot deformities and osteotomy of the right tibia. Perioperative complications have been significant. Currently, her height and weight are those of a 2 1/2-year-old child, and she has the bone age of a 3 1/2-year-old child. Nevertheless, she is in first grade at a regular school. Certainly, the prognosis for patients with campomelic dysplasia is guarded, but some survivors may be helped by judicious orthopedic care.

Bone Diseases, Developmental↗
PubMed1983

Studies in antifertility agents--Part XLI : Secosteroids--X : Syntheses of various stereoisomers of (+/-) 2,6 beta -diethyl-7 alpha -ethynyl-3-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7 beta-ol.

The syntheses of (+/-) 2 alpha,6 beta -diethyl-7 alpha -ethynyl-3 alpha-(p-hydroxyphenyl)-trans- bicyclo[4.3.0]nonan-7 beta-ol (8), (+/-)2 beta,6 beta-diethyl-7 alpha-ethynyl-3 beta-(p-methoxy-phenyl)-trans-bicyclo[4.3.0]nonan-7 beta-ol 12 and (+/-) 2 alpha,6 beta-diethyl-7 alpha-ethynyl-3 beta-(p-hydroxyphenyl)- trans-bicyclo[4.3.0]nonan-7 beta-ol (18) and their derivatives, which are essentially B-seco-steroids having cis-anti-trans, cis-syn-trans and trans-anti-trans geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that trans-anti-trans compounds are biologically most potent, followed by the corresponding cis-anti-trans and cis-syn-trans compounds. The most potent compound 18 is active at 1 mg/kg in rats. Introduction of 7 alpha-ethynyl group increases their AI activity; however, no significant effect on their RBA is observed.

Animals↗
PubMed1983

Antifertility agents. 38. Effect of the side chain and its position on the activity of 3,4-diarylchromans.

In a study of the effect of the substituent on the receptor binding affinity (RBA), estrogenicity, and antiimplantation (AI) activity in trans-3,4-diarylchromans, it has been found that demethylation of trans-2, 2-dimethyl-3-phenyl-4-[p-(beta-pyrrolidinoethoxy)phenyl]-7-methoxychroman (centchroman, 1) to the corresponding 7-hydroxy compound (7) results in a 20-fold increase in RBA (112%) without any appreciable change in AI activity. On the other hand, absence of the pyrrolidinoethyl group from the 4-phenyl residue (6) leads to a drop in both RBA and AI activity. A chain length of two to three carbon atoms and a pyrrolidino ring appear to be necessary for activity in these compounds. It has been found that while the trans isomers with the tertiary aminoalkoxy side chain in the para position of the 4-phenyl radical were the most active, in the corresponding cis-chromans and chromenes, analogues with this chain in the meta position were most active; the ortho substituted compounds of all these series were inactive. In 3-phenyl-substituted compounds, the trans isomer carrying the p-hydroxy substituent (33) was found to be the most active; the corresponding pyrrolidinoethyl ether (13) showed a lower order of activity. The implication of these observations on the mapping of the different subsites on the receptor has been discussed.

Animals↗