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Biomedical subjects

R M Abrams

Publications and source records attributed to R M Abrams.

At least 73 records · Page 4Linked to original sources
PubMed1985

Energy metabolism of the developing brain.

Cerebral metabolism in utero and in the neonatal period remains incompletely understood. A major investigative technique uses 14C deoxyglucose. Species differences, behavioral states and gestational age all have an impact. Hormonal and sensory stimuli have potential influences. The use of this new investigative technique in the human will allow detailed study of the effects of a variety of pathophysiologic events and possibly of drug therapy on cerebral glucose metabolism.

Animals↗
PubMed1984

Effect of ethyl alcohol infusions on glucose and hormone status in ovine pregnancy.

Term pregnant ewes were given ethanol in dextrose water i.v. according to the usual 2-h loading dose recommended for premature labor. Glucose, insulin, cortisol, progestins, estrone and estradiol in maternal and fetal plasma were measured for 5 h. In both treated animals and controls (dextrose water only) there was reduction in maternal cortisol and a reduction followed by a rise in progesterone concentration. Mean concentration of insulin in maternal plasma across all sampling times was higher in ethanol treated animals.

Animals↗
PubMed1984

Local cerebral glucose utilization in fetal and neonatal sheep.

The newborn mammalian brain of several species has been shown to have a lower average rate of energy metabolism and a narrower range of rates in its various components than is found in maturity. In a further study of cerebral energy metabolism during development, we have employed the [14C]deoxyglucose method for measuring local cerebral glucose utilization in fetal and neonatal sheep. After establishing the lumped constant to be 0.40 and finding the rate constants for the kinetic behavior of deoxyglucose in plasma and brain to be close to those in other species, we measured the rates of glucose utilization in 44 regions of the brain. The rates were low and homogeneous in midgestation, except for those of brain stem nuclei of the auditory and vestibular systems and those of the hippocampus which were relatively high. In the last 7 wk, local rates rose approximately threefold. After birth there was a further average increase of 50% above full-term levels. The study shows that cerebral energy metabolism rises in most structures during prenatal maturation, a time when sensory stimulation is at a relatively low level and behavioral responses are minimal.

Animals↗
PubMed1983

Changes in the LH response to GnRH in the ovine fetus and neonate.

The in vivo responsiveness of the ovine fetal and neonatal pituitary was investigated using acute and chronic preparations. Several studies were performed on six fetuses and six lambs from 112 days' gestation through 5 weeks after birth. Ten micrograms of gonadotropin-releasing hormone (GnRH) was injected intravenously into each fetus and lamb, and serial blood samples were collected from the fetus, ewe and lamb. The luteinizing hormone (LH) content of each sample was determined by species-specific radioimmunoassay. Both the fetus and the neonate showed a response to GnRH. A significant elevation of LH was found in all animals by 15 minutes. There was no response in the ewe when GnRH was injected into its fetus. Great variability in response was noted among various age groups and between animals, with the maximum individual LH response reaching 33.7 ng/ml. The maximum LH response of the neonate during the first week of life was significantly depressed (p < 0.05) as compared to that of the fetus and the older neonate.

Age Factors↗
PubMed1982

Effect of conjugated estrogens on vaginal blood flow in surgically menopausal women.

The effect of an intravenous bolus of 25 mg of conjugated estrogen (Premarin) on vaginal blood flow in seven surgically menopausal women was measured by a thermal conductance probe. Electrical power (0.8 W) was supplied to a resistance wire incorporated in the surface of the probe, and its surface temperature was monitored continuously for 30 minutes six times daily for 3 days. The mean temperature difference (delta T) between the heated probe surface and the vagina remained unchanged during a preinjection control day. While there were individual differences in response, analysis of mean delta T during the first day following the injection of the estrogen revealed a significant linear downward trend at delta T, indicating a rise in vaginal blood flow. Delta T plateaued on day 2 and showed a slight rise in the morning of day 3. It may be concluded that estrogen administered in this dose and form markedly increases vaginal blood flow.

Adult↗
PubMed1982

Fetal death in utero: effect on estrone, estradiol-17 beta and progesterone levels in the ewe.

Polyvinyl catheters were placed in the maternal femoral artery (MA) and maternal uterine vein (UV) of 11 near-term ewes and in the umbilical vein of their fetuses. 1-5 days postoperatively 100 ml of air were injected into the umbilical vein of 7 fetuses. 4 fetuses served as controls. Samples of blood from MA were taken 15 min prior to air embolism and every 15 min for 3 h, then at +4, +5 and +6 h after air injection. Plasma levels of estrone (E1) estradiol (E2) and progesterone (P) were determined by radioimmunoassay. In MA and UV of treated ewes there was a significant decrease in P, but not in E1 or E2 after fetal death compared to control ewes. Control levels of P in MA were 9.6 ng/ml; values at 1, +2, +4 and +6 h were 8.8, 3.3, 2.3 and 1.2 ng/ml, respectively.

Animals↗
PubMed1982

A statistical approach to the determination of the fertile period.

17 beta-Estradiol (E2), basal body temperature (BBT) and luteinizing hormone (LH), were measured in normally menstruating women. The preovulatory E2 observations were characterized by variations about a constant level during the preovula-peak. The BBT observations typically varied about a constant level during the preovulatory phase then about a higher constant level during the postovulatory phase. The change points in E2 and BBT were detected using a Bayesian detection rule and a midcycle 'fertile period' was marked off. The midcycle 'fertile periods' appear to bracket the ovulation event and the method shows promise as a natural family planning method. Several practical limitations of the method are discussed.

Bayes Theorem↗
PubMed1981

Some properties of rectum and vagina as sites for basal body temperature measurement.

The choice of site for body temperature measurement and consistency in positioning the thermometer are important in achieving reliable and interpretable basal body temperature graphs in women. The distribution of temperatures in vagina (TV) and rectum (TR) were measured in women upon awakening. There were no significant differences between TR and TV at insertion depths of 5, 9, or 13 cm. Estimation of deep body temperature was not improved by inserting a thermojunction beyond 5 cm in vagina or rectum. Rates of change in TV following ingestion of a 300-ml iced drink were significantly greater than rates of change in TR.

Adult↗
PubMed1981

Effect of ethyl alcohol on maternal and fetal acid-base balance and cardiovascular status in chronic sheep preparations.

Thirteen chronically catheterized pregnant sheep were given intravenous infusions of 10 per cent ethyl alcohol in 5 per cent dextrose solution (15 mg/kg over two hours). Samples of blood from maternal femoral artery, uterine vein, and fetal brachiocephalic artery were drawn at hourly intervals before, during and after the infusions. Plasma was analyzed for alcohol concentration, protein concentration, haematocrit, PCO2 and pH. Maternal and fetal arterial blood pressures were monitored continuously. There were no significant differences between maternal and fetal arterial blood alcohol levels at any sampling interval nor was there any difference in elimination constants. Alcohol infusion did not produce any significant change in plasma protein concentration, haematocrit, PCO2 and pH, and mean arterial blood pressure in either mother or fetus. However, both maternal and fetal heart rate increased significantly following alcohol infusion.

Animals↗
PubMed1981

New thermal method for evaluating vaginal blood flow.

The goal of this study was the development noninvasive technique for measurement of vaginal blood flow. A vaginal probe (diameter 1.84 cm; length 7.0 cm) was constructed by winding 23 m of 34-gauge enameled copper wire around a hollow cylinder of epoxy-impregnated glass wool. Resistance of the wire was 20 omega at 40 degrees C. Surface area of coil was 40.5 cm2. The temperature of the wire midway along the coil was measured continuously with a thermcouple. Temperature difference (delta T) between coil and vagina was raised by delivery of 300 mA with a resultant production of 1.8 W. In ewes treated with 1 mg estrone im., delta T fell significantly (p less than 0.025) by 90 min and (p less than 0.005) by 120 min after injection. There was a significant correlation between delta T and vaginal blood flow as measured by the radiolabeled microsphere technique.

Animals↗
PubMed1980

The adjustment of basal body temperature measurements to allow for time of waking.

During one menstrual cycle, each of eleven volunteer student nurses at Northwick Park Hospital recorded their vaginal temperature on waking and noted the clock time. Waking times varied between 0530 hours and 1100 hours. Regression analysis revealed significant linear relation between temperature and time of waking, with a slope of 0.086 degrees C/hour (SE, 0.009 degrees C/hr) in the postmenstrual (hypothermal) phase. A rounded adjustment factor of 0.1 degrees C/hour is shown to improve the interpretability of basal body temperature (BBT) charts in a group of seven women regularly using natural family planning methods. The adjustment factor is simple to apply and only involves counting one square on a BBT chart for each hour that the waking time differs from normal.

Body Temperature↗
PubMed1980

Thermal features of the female axilla.

Axillary (Tax), vaginal (Tv), and sublingual (Tsl) temperatures were measured in 12 women between 0600 and 0730 h prior to their arising from bed. Isothermal maps made of closed axilla 30 min after thermojunctions had been inserted showed a distribution of several temperatures, the lowest Tv-Tax isotherm occupying approximately 40% of the anteroposterior distance. Tax at this point was 0.1 to 0.5 degrees C less than Tv and -0.03 to 0.26 degrees C less than Tsl. The time course of Tax rise varied considerably among subjects, with the slowest still rising 30 min after insertion, whereas the fastest was almost steady after 3 min. The width of the 0.5 degrees C isotherm along the fold averaged 5.8 cm and occupied about 60% of the axillary width. A significant negative correlation was noted between width of the 0.5 degrees C isotherm and Tv-Tax. Effects on the time course of 1) preexposure to air of the axilla for 5 min and 2) different initial thermometer temperatures (10 and 30 degrees C) were studied in 6 women. Analysis of variance showed a significantly higher value of Tax (10 min)-Tax (3 min), i.e., a slower time course with the cooler thermometer. The effects of exposure of the axilla were much more pronounced.

Adult↗
PubMed1980

An objective method for detecting the shift in basal body temperature in women.

The upward shift in basal body temperature (BBT) observed in women of child-bearing age is often used as an indicator that ovulation has occurred and that a period of infertility has begun. In natural family planning programmes it is important to detect the BBT shift reliably and with a minimum of user uncertainty, against a background of physiologically induced temperature variations. The cumulative sum (CUSUM) test is adapted to the problem of detecting BBT shift and applied to 137 BBT charts obtained from 21 women using natural family planning. Results show successful detection of the shift in all cases. Shifts occurred at gynaecologically appropriate times in the menstrual cycle.

Analysis of Variance↗
PubMed1979

Energy metabolism.

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Adenosine Triphosphate↗
PubMed1978

Vaginal blood flow during the menstrual cycle.

Six nulliparous young women slept 16 to 27 consecutive nights in a clinical research center. Vaginal blood flow was estimated from rates of removal of heat from the vaginal wall by a cooled probe inserted by the women immediately upon awakening. Plasma levels of estradiol, progesterone, luteinizing hormone, and follicle-stimulating hormone were determined. Measured also were vaginal temperature and systolic and diastolic blood pressures. Systematic changes during the cycle were detected for all variables except systolic blood pressure. Rising levels of estradiol during late follicular phase were not correlated significantly with vaginal blood flow rates.

Adult↗
PubMed1978

Energy metabolism in the exteriorized fetus.

Umbilical blood flow rate (UBF) was measured in 9 exteriorized fetal lambs by weight changes of the fetus during total umbilical vein occlusion. Concentrations of oxygen, lactate and pyruvate in umbilical arterial (UA) and umbilical venous (UV) blood were determined. Rate of fetal oxygen consumption (.QO2) was 5.2 +/- (SEM) 0.48 ml. kg(-1) . min (-1), and was correlated with UBF (r = 0.793), but not with the content of O2 in UA or UV. The UV-UA differences in lactate/pyruvate ratios indicated varying degrees of anaerobic metabolism in those fetuses with highest UBF and .QO2, but not in poorly perfused fetuses with low .QO2. Fetal exteriorization can result in inadequate perfusion of fetal tissue, lowering of fetal oxygen consumption and some anaerobic metabolism.

Animals↗
PubMed1978

Percutaneous indirect lymphography with a new experimental contrast medium: a preliminary report.

Suspension of tetraiodotheraphtalic acid-bis-oxyethylester (120-480 mg I/ml) was injected percutaneously into the testicles, mammary glands, and the cervix of the uterus in mongrel dogs. The suspension was rapidly absorbed by the lymphatics draining the injection sites and transported to the regional lymph nodes. Excellent filling of lymphatics and nodes was apparent immediately or a few minutes after injection. Because of locally produced inflammatory reaction, percutaneous indirect lymphography with tetraiodotherephtalic acid-bis-oxyethylester is now applicable only in experimental animal studies.

Animals↗