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Biomedical subjects

H Brown

Publications and source records attributed to H Brown.

At least 163 records · Page 9Linked to original sources
PubMed1982

Beta 2-microglobulin excretion and urinary cytology in analgesic nephropathy.

Patients with analgesic nephropathy are at risk from uro-epithelial malignancy. Enhanced secretion of beta 2-microglobulin occurs from epithelial cancer cells. In order to find a screening test for malignancy in analgesic nephropathy, urinary levels of this protein were measured in patients with analgesic nephropathy with urine cytological abnormalities and were compared to a control group with glomerulonephritis. Mean fractional excretion of beta 2-microglobulin was higher (8.61 +/- 1.76 SEM) in patients with analgesic nephropathy than in those with glomerulonephritis (1.13 +/- 0.76) (P less than 0.025). Those patients with analgesic nephropathy who had malignant cells in the urine had higher mean fractional excretion (18.56 +/- 5.77) than those with only atypical cells (8.5 +/- 2.0) (P less than 0.05) who in turn had higher mean values than those with normal cytology (2.12 +/- 0.62) (P less than 0.0025). It is suggested that the increased beta 2-microglobulin excretion in analgesic nephropathy is due to secretion from abnormal urothelial cells as well as reduced tubular catabolism. Beta 2-microglobulin may be of use as a screening test for malignancy in analgesic nephropathy.

Adult↗
PubMed1981

Effect of differential rearing on brain, liver and adrenal tissues.

Brain, liver, and adrenal weights were measured in rats differentially reared from 28-60 days of age. Relative to the standard colony rats, enriched rats had heavier brains but lighter livers. Relative to the standard animals, impoverished rats had heavier adrenals. These results confirm differential rearing influences on organs other than the brain.

Adrenal Glands↗
PubMed1981

Developmental changes in brain template active region chromatin.

The percentage of brain or liver chromatin in the template-active region was examined in rats of varying ages. Prenatally, there was an increase in the percentage of brain template-active region chromatin which declined near birth. After birth, the percentage of brain template-active region chromatin again increased to 3-6 days of age and then declined to adult levels at about 15 days of age. Liver exhibited a similar gestational change in the percentage of template-active region chromatin, but there was no recovery from the birth decline during postnatal development. These findings are discussed in terms of their contribution to the understanding of age-dependent changes in brain transcription.

Aging↗
PubMed1980

Corticosterone effects on rat brain template active region chromatin.

The effect of prenatal exposure to corticosterone on brain chromatin was examined. Pregnant Fischer inbred rats were administered corticosterone or saline on Days 17 and 18 of gestation and their offspring examined at 0 (day of birth), 2, 3, 4 or 6 days of age. In utero exposure to corticosterone was associated with a 24 hr delay of a developmental peak in the percentage of brain template active region chromatin. Brain and body weights of the steroid and saline-treated animals were similar, but corticosterone led to a temporary decrease in body and brain weight at 2 days of age which was reversed at 6 days of age. These results of these studies suggest an impact of corticosterone on brain gene expression.

Animals↗
PubMed1980

The contribution of potassium accumulation to outward currents in frog atrium.

1. Voltage-clamp experiments on frog atrial muscle were designed to distinguish effects due to K accumulation in extracellular spaces from those due to activation of K conductance mechanisms in the membrane. 2. The set of instantaneous current-voltage relations obtained at various external K concentrations following depolarization to about -10 mV for several seconds was found to be quite different from that obtained before the depolarization. Hence the process of increasing the extracellular K concentration cannot account for all the time-dependent changes in outward current during depolarization. 3. Although the instantaneous current-voltage relations obtained at different values of external K concentration before prolonged depolarization show the cross-over phenomenon (Noble, 1965), those obtained at the end of the depolarization did not show this feature. It is concluded that the current-voltage relations for the channels conducting the time-dependent K current do not show cross-over. 4. These results were used to construct a model involving both K activation and K accumulation. This model successfully reproduces the appearance of a very slow component in outward current decay tails which, when subtracted by semi-exponential curve-stripping leaves a component with the real time constant of conductance change. The model does not however reproduce the appearance of a fast decaying component without adding a second conductance mechanism, or assuming non-exponential decay of a single conductance mechanism. 5. It is therefore suggested that i chi, fast is not a perturbation of i chi, slow or of iK1 by the process of K accumulation. This conclusion is reinforced by the results of experiments showing that the relative magnitude of i chi, fast is not greatly changed by substantially increasing the external K concentration in order to reduce the proportionate effect of K accumulation on the K concentration.

Animals↗
PubMed1980

Voltage-clamp investigations of membrane currents underlying pace-maker activity in rabbit sino-atrial node.

1. Small preparations of spontaneously beating rabbit sino-atrial node have been investigated using the two micro-electrode voltage-clamp technique. 2. Hyperpolarizing clamp pulses given from holding potentials of about -45 mV reveal a time-dependent change of a membrane current, if, which is shown to overlap the pace-maker range (-65 mV to -45 mV) for these preparations. 3. The changes in if are shown to be quite distinct from the de-activation of the time-dependent outward current, iK. 4. The time-dependent changes of the if system increase during adrenaline application and therefore contribute to the chronotropic action of adrenaline on the heart. 5. Evidence for a link between slow inward current (iSi) and time-dependent outward current (iK) in rabbit sino-atrial node is presented and assessed.

Animals↗
PubMed1980

Estimates of partial efficiency of young beef bulls.

Gain, feed consumption and feed efficiency records of 1,409 bulls that were individully fed at central test stations were analyzed. Feed for maintenance and feed for gain were estimated and used to study partial and gross efficiency and relative feed intake. Among the eight breed groups represented there was a range of 3.4% in the breed means for partial efficiency and of 1.6% in the means for gross efficiency. Relative feed consumption ranged from 2.82 to 3.10 times maintenance among the eight breed groups. Effects associated with location, year, breed and the interactions among these effects were significant for traits related to partial efficiency. If the bulls presented to these central tests are representative of their respective breeds, these results emphasize the importance of making comparisons within tests and finding more efficient cattle within the breed of choice.

Animal Feed↗
PubMed1979

An annotated bibliography of the remarried, the living together, and their children.

This bibliography was developed by the Remarried Consultation Center of the Jewish Board of Family and Children's Services of New York City for our own use. Because there is a growing interest in remarriage and the new types of families this social phenomenon creates, we became convinced that the meager number of articles and books in this area would be of interest to others. We have focused our attention on the now common phenomenon of the remarried and those living together in a committed relationship situation. Some articles that were not designed as studies of remarriage situations are included because their content is pertinent to our subject. The bibliography is divided into six sections to facilitated reference use. It should be noted, however, that these sections are not rigid and that some items could readily have been included under two or more sections. Articles included cover publication dates through April 1978. The six sections are: I. Demography; II. Remarried Couples; III. Stepparents and Stepchildren; IV. Divorce as a Precursor to Remarriage; V. Children of Divorce in Relation to Remarriage; VI. Remarriage-Prophylactic and Therapeutic Aspects. Unfortunately we did not find sufficient material to warrant a section on theoretical aspects. We have tried to make this bibliography as complete as possible using two computer retrieval systems as well as our own search of the literature. If you are familiar with references we have missed, we should appreciate hearing from you.

Adult↗
PubMed1979

Cardiac pacemaker oscillation and its modulation by autonomic transmitters.

1. A scheme is presented which summarizes the activation and deactivation of the membrane currents which underlie pacemaking in the natural pacemaker of the heart. 2. Experimental evidence (mostly obtained using the voltage-clamp technique) for the properties of the time-dependent membrane currents in pacemaking tissue of the frog and the rabbit is discussed. 3. The mode of the inhibitory action of acetylcholine on pacemaker cells is considered. In the amphibian pacemaker cell, acetylcholine probably reduces slow inward current (as it certainly does in amphibian atrium) but in mammalian sino-atrial node it seems that such action, if present at all, is much less marked. In the pacemakers of both amphibian and mammal, acetylcholine greatly increases outward potassium current and there is recent evidence that it may do so by opening up a special acetylcholine-activated potassium channel. 4. Adrenaline greatly increases the slow inward current in pacemaker as in other cardiac tissues. This increase, together with (in mammal at least) an increased change of an additional pacemaking current, overrides an adrenaline-induced increase in outward current and leads to acceleration of the pacemaking rate. 5. The Appendix contains a brief consideration of the experimental and theoretical basis for the method of exponential separation of outward current components in the presence of the extracellular potassium accumulation that inevitably accompanies the flow of outward membrane current.

Acetylcholine↗