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Biomedical subjects

K Ryan

Publications and source records attributed to K Ryan.

At least 91 records · Page 5Linked to original sources
PubMed1987

The effect of ethanol and acetaldehyde on Na pump function in cultured rat heart cells.

To further define the sarcolemmal effects of ethanol and acetaldehyde, their effects on Na pump function were studied in synchronously contracting monolayers of neonatal rat myocardial cells. The effects of ethanol (10 mg/dl to 1000 mg/dl: 2 X 10(-3) M-0.2 M) and acetaldehyde (10(-6) M to 10(-4) M) on total 42K influx, ouabain-sensitive 42K influx, Na pump density (from specific 3H-ouabain binding) and pump turnover rates were measured. Applied acutely ethanol had no effect on 42K influx but after 30 min of treatment 42K influx was decreased by 13%, 23% and 48% in 100 mg/dl, 300 mg/dl and 1000 mg/dl ethanol respectively. This primarily reflected a decrease in mean ouabain-sensitive K+ influx from a control of 12.54 to 9.90, 8.95 and 6.68 (p-mol/cm2/s) in 100, 300 and 1000 mg/dl (2 X 10(-2) M, 6 X 10(-2) M) ethanol. Acetaldehyde in the concentrations tested had no effect on K+ influx. Ethanol treatment produced a decrease in Na pump density, maximum within 30 min and dose-dependent, at concentrations of 100 mg/dl (22%), 300 mg/dl (37%) and 1000 mg/dl (55%). Acetaldehyde had no effect on Na pump density. In the presence of ethanol (300 mg/dl and 1000 mg/dl) intracellular Na+ increased significantly and the Na+ efflux declined in parallel with the K+ influx. From the ouabain-sensitive K+ and Na+ fluxes and the Na pump density individual pump turnover rates were calculated at 62.5/s in control cells and 66/s and 84/s in cells treated with 300 mg/dl (6 X 10(-2) M) and 1000 mg/dl (0.2 M) respectively. We conclude that ethanol, but not acetaldehyde has a depressant effect on sarcolemmal Na pump function. The results suggest this is due primarily to a decrease in the number of sarcolemmal Na pump sites.

Acetaldehyde↗
PubMed1987

Effects of acute, in utero, alcohol exposure on growth and electrolyte metabolism in male offspring of C57BL/10J mice.

The effects of acute low-dose maternal alcohol exposures were investigated in C57B1/10J mice offspring. Pregnant mice were randomly placed into three alcohol groups and were injected twice intraperitoneally on gestation day 7, 0 hours and gestation day 7, 4 hours, with one of the following dosages of 25% alcohol: Group 2 received 1.25 Gm/Kg body weight; Group 3 2.50 Gm/Kg body wt.; Group 4 3.75 Gm/Kg body wt. A control group (Group 1) received .015 ml/gm body wt. of physiological saline. At birth all offspring were weighed and observed for any gross physical abnormalities. On day 25, all female offspring and mothers were sacrificed. The male pups were maintained until day 61. On day 61, the male pups were placed in individual metabolic cages where food and water consumption, and urine excretion were monitored for 24 hrs. On day 62, these animals were sacrificed. Blood was drawn for serum calcium (Ca) and phosphorous (P) determination. Brains, kidneys, testes, hearts and thymus glands were removed and weighed. Ca and P levels were also measured in the urine. No significant difference in litter size and fetal weight was obtained among the four groups. There was no evidence of physical abnormalities in the alcohol groups compared to the control one. The 62 day old pups from all three alcohol groups had significantly lower serum and urine levels of Ca and P than the control group, with the lowest values recorded for Group 4. There was no significant difference in final body weight but small organ size differences were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Maternal social support as a predictor of mother-child stress and stimulation.

There is increasing interest in the role of social support in determining risk for child abuse and neglect. The present study assessed the relationship between maternal social support and two areas: stress in the mother-child relationship: and level of stimulation provided in the home. Maternal social support was assessed prenatally and at a two-year follow-up, while the latter variables were compiled at the two-year follow-up. The data were obtained from 38 urban, low SES (80% on public assistance) mothers and their 2-year-old children. Maternal social support correlated positively with level of stimulation and negatively with level of mother-child stress, and was the best predictor of both, relative to any SES, mother or child variables. In addition, high stress, low support mothers provided significantly less stimulation to their children. The theoretical implications for social support as a mediator variable as well as its implications for early identification and prevention efforts in abuse and neglect are discussed.

Adolescent↗
PubMed1985

Biphasic progesterone synthesis by the hamster preovulatory follicle in vitro.

In vitro time course studies of progesterone and protein synthesis by hamster preovulatory follicles (harvested prior to the proestrous gonadotropin surge) were done. LH appears to stimulate progesterone synthesis in 2 phases. The first phase lasts 0 to 4 or 5 hr and is not inhibited by either puromycin or cycloheximide. The second phase (apparent by 4-5 hr) is distinguished from the first phase by its inhibition by puromycin and cycloheximide, and by the differential dose response of dibutyryl cyclic AMP on the respective 2 phases. Incorporation of a H-labelled mixture of amino acids into protein is not seen in LH-stimulated follicles in 2 hr incubations but is apparent by 4 hr. The LH-stimulated protein synthesis is inhibited by puromycin. The results indicate that although LH stimulates both phases of progesterone synthesis, the mechanisms may be different for each phase.

1-Methyl-3-isobutylxanthine↗
PubMed1982

The appreciation of imagery by schizophrenics: an interpretation of Goldstein's impairment of the abstract attitude.

Three experiments are reported in which schizophrenics are compared with other psychiatric patients on (i) the imagery value of words in their speech, (ii) their memory for words differing in imagery value, and (iii) their ability to distinguish the imagery value of two words. The study was designed to evaluate a neglected interpretation of Goldstein's ideas that schizophrenics are more concrete, in that their 'action is determined by momentary sense impressions'. The results gave no support for this interpretation and it is suggested that an abnormal way of categorizing the world is more likely to be a useful way of formulating Goldstein's ideas.

Adult↗
PubMed1977

Diphosphonate therapy of paget's disease of bone.

The use of disodium ethane-1 hydroxy-1, 1-diphosphonate (EHDP) therapy for Paget's disease of bone was examined in 75 affected patients. Forty-eight patients received randomly assigned oral doses of either 0, 2.5, 5, 10, or 20 mg/kg/day in a controlled, double-blind protocol, and the remainder received either 10 or 20 mg/kg/day in a non-random protocol. The clinical status of the patients and appropriate laboratory tests were evaluated before treatment and at frequent intervals during a six-month period of initial therapy. There were no significant changes in either urinary hydroxyproline or serum alkaline phosphatase in those patients receiving placebos, while both these parameters decreased significantly at all dose levels of EHDP, with the greatest decline noted in the highest dose group. However, statistical analysis of the data related to changes in symptoms in the double-blind study revealed that patients receiving the higher dose of EHDP (10 or 20 mg/kg/day) had less favorable outcomes than those receiving the lower doses (2.5 or 5 mg/kg/day). The high does group had a relatively lower rate of symptom improvement and a relatively greater rate of deterioration than did the low dose group. Twenty-one of forty-nine patients followed for at least 18 months have shown a sustained suppression of their serum alkaline phosphatase and urinary hydroxyproline values for 12 months following cessation of EHDP, while therapy has been reinstituted for the other 28 patients because of increases in these measurements, with or without accompanying symptomatic deterioration. Eight patients sustained fractures through Pagetic bone during the period of study and all of these were treated with higher doses of EHDP. On the basis of the biochemical and clinical data in this study it appears that initial therapy of Paget's disease of bone with 5 mg EHDP/kg/day maximizes benefits while minimizing possible adverse effects.

Alkaline Phosphatase↗
PubMedDate not supplied

Expression of mouse and frog rRNA genes: transcription and processing.

This article summarizes a number of lines of investigation of rRNA gene expression that are ongoing in the laboratory. These studies focus on mouse and frog, two distant vertebrate species. One major conclusion is that the basic properties of rRNA gene expression appear remarkably well conserved in evolution, with only relatively minor perturbations between frog and mouse, contrary to the common interpretation of the species-selectively between mouse and human rDNA transcription (e.g., 1). This is true both for the process of rDNA transcription and for the subsequent rRNA processing event.

Animals↗
PubMedDate not supplied

Prevalence of sexually transmitted diseases in Mexican-American pregnant women by country of birth and length of time in the United States.

BACKGROUND AND OBJECTIVES: The prevalence of sexually transmitted diseases in Hispanic prenatal patients has not been well documented. Studies of disease prevalence in Hispanic patients often are complicated by multiple countries of origin and the combining of foreign-born and U.S.-born Hispanics into a single category. GOAL OF THE STUDY: The purpose of this study was to document the prevalences of sexually transmitted diseases in low-income, pregnant Mexican-American women and to compare the prevalences of those born in the United States with those born in Mexico. We also compared the prevalence of those who recently arrived from Mexico with those who had been in the United States a longer time. STUDY DESIGN: Three-hundred-forty-seven pregnant women attending a clinic for low-income populations were screened for syphilis, gonorrhea, chlamydia, and hepatitis B virus on their first perinatal visit. RESULTS: Thirty-five women (10.1%) were positive for chlamydia, four (1.2%) for gonorrhea, one (0.3%) for syphilis, and none for hepatitis B virus. Women born in Mexico reported fewer past chlamydia and total sexually transmitted disease infections than Mexican-Americans and non-Hispanic whites born in the United States However, the prevalence of chlamydia and total sexually transmitted diseases did not differ by ethnicity, country of birth, or length of time in the United States The only variable correlated with chlamydia infection was the presence of vaginal discharge, but the sensitivity of this symptom was too low to be clinically useful as a means of selective screening. CONCLUSION: Low-income women of Mexican ancestry should be routinely screened for syphilis, gonorrhea, and chlamydia as part of their prenatal care in the United States. The value of hepatitis B virus screening in this population was neither supported nor refuted by this study.

Adult↗