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Biomedical subjects

S Ray

Publications and source records attributed to S Ray.

At least 109 records · Page 6Linked to original sources
PubMed1987

Enhanced antifertility activity of non-steroidal molecules with 3-n-butylamino-2-hydroxypropyloxy side chain.

A comparative study of relative binding affinity (RBA) for estradiol-17 beta-receptors, estrogenicity and antifertility activity of compounds 2,2-dimethyl-3-phenyl-4-p-(3-n-butylamino-2-hydroxypropyloxy-pheny l)- 7-methoxycoumarin 4, 2,2-dimethyl-3-phenyl-4-p-(3-n-butylamino-2-hydroxy-propyloxyphenyl++ +)-7-methoxy chromene 5 and trans-2,2-dimethyl-3-phenyl-4-p-(3-n-butylamino-2-hydroxypropyloxyphe nyl)- 7-methoxychroman 6 with the corresponding 4-p-(beta-pyrrolidinoethoxyphenyl) compounds 1-3, is reported. It has been found that the introduction of the novel 3-n-butylamino-2-hydroxypropyloxy moiety in place of the classical tert-beta-aminoethoxy group leads to enhancement of antifertility activity.

Animals↗
PubMed1987

Neutrophil leukocyte morphology, cigarette smoking, and palmoplantar pustulosis.

Neutrophil leukocyte morphology was examined in whole blood films from 20 patients with palmoplantar pustulosis (PPP) and 32 healthy controls. In the PPP patients, there was a significant increase in the number of neutrophils having polarized morphology or membrane ruffling; however, there was no significant difference in neutrophil morphology between cigarette smokers and nonsmokers, suggesting that the epidemiologic link between smoking and PPP is not explained by increased polarization of peripheral blood neutrophils.

Cell Membrane↗
PubMed1986

Bioaccumulation of cadmium in marine organisms.

It has been established that, although Cd occurs in the marine environment in only trace concentrations, most marine organisms, especially molluscs and crustaceans, can accumulate it rapidly. Cadmium is not uniformly distributed in the body and selectively accumulates in specific organs like liver, kidney, gills, and exoskeleton. The concentrations in muscle tissues are several orders of magnitude lower. The disposition of Cd in the organisms in the laboratory studies generally parallels those in nature. A number of biotic factors like body size, maturity, sex, etc. influence bioaccumulation but extensive studies are still lacking. The chemical form of Cd in the environment is of prime importance in bioaccumulation by marine organisms. Salinity can affect the speciation of Cd, and bioaccumulation is affected by both temperature and salinity. The ultimate level of Cd in the organisms will depend not only on the biotic and abiotic factors but also on metabolism of the metal by the organisms. A few studies indicate depuration of Cd by some bivalves but other organisms show very effective retention of Cd. Metallothionein formation for detoxification and storage has been observed in a large variety of marine organisms. Recent reports indicate an alternate storage and excretion mechanism in the formation of membrane-limited vesicles or granules. There seems to be a common link between intracellular localisation of Cd in metal-binding proteins and Cd containing vesicles as detoxifying mechanisms in the marine organisms. Much of what is known about Cd bioaccumulation by marine organisms has come from laboratory studies and there are inherent dangers in trying to extrapolate the results to field situations. In spite of tremendous progress made over the years, the basic understanding of the bioaccumulation process is still very nebulous and will remain so until the uptake, storage, and elimination processes are fully understood.

Animals↗
PubMed1986

17 alpha-allyl estradiol analogues as candidates for development of high-affinity fluorescein-estradiol conjugates.

In order to develop stable, high-affinity fluorescein-estradiol conjugates, the fluorescein moiety must be leashed to the estradiol molecule at a point which interferes least with estradiol's binding to the receptor. Because of the high affinity of 17 alpha-substituted estradiol (e.g. ethynyl estradiol), we investigated a series of 17 alpha-substituted estradiol compounds to determine the optimal properties of a leash at this position. Twelve estradiol derivatives bearing a three-carbon 17 alpha side chain with or without a terminal functional group and with varying degrees of unsaturation were synthesized. Initial comparison of the receptor binding affinities of some of these derivatives suggested that three factors might reduce affinity: internal hydrogen bonding of the 17 beta-hydroxyl proton with an oxygen atom of the 17 alpha side chain; hydrophilicity of the ligand; or steric interference of the side chain with receptor binding. Further comparisons were designed to evaluate the relative contribution of these factors. The results suggest that the relative affinities of these 17 alpha-substituted estradiol derivatives are influenced primarily by the steric interference of the side chains and also by their hydrophilicity. Internal hydrogen bonding involving the 17 beta-hydroxyl proton does not seem to have a profound effect.

Animals↗
PubMed1986

Androgen receptor affinity chromatography: synthesis and properties of 17 alpha-epoxypropyl-dihydrotestosterone Sepharose.

We have prepared a new affinity chromatography reagent, 17 alpha-epoxypropyl-dihydrotestosterone linked to Thiopropyl-Sepharose, with potential for use in purification of androgen receptor and other specific androgen binding proteins. The linkage is stable, and the ligand has reasonably high affinity for the receptor. Starting with 5 alpha-androstane-3 beta-ol-17-one, we synthesized in two steps 17 alpha-allyl-dihydrotestosterone, which was then oxidized to 17 alpha-epoxypropyl-DHT yielding 2 diastereomers in about a 4:1 ratio. The 17 alpha-allyl-DHT had about 50% of DHT's affinity for rat uterine androgen receptor, while the affinity of the major epoxide isomer was 9% and that of the minor isomer was 4%. Reaction of the epoxides with Thiopropyl-Sepharose-6B gave about 7 mumol of covalently bound DHT per ml of beads. These beads took up 83% of the androgen receptor from a rat uterine cytosol in a preliminary study, which more than equalled the performance of identically prepared estradiol beads successfully used for estrogen receptor purification. The use of the new DHT beads in purifications of the androgen receptor and other binding proteins is now being explored by other laboratories.

Animals↗
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↗