PubMed Health⌕ Search

Biomedical subjects

R E Young

Publications and source records attributed to R E Young.

16 recordsLinked to original sources
PubMed1992

Bioelectrical-impedance analysis as a measure of body composition in a West Indian population.

Percent body fat (%BF) was estimated in 50 males and 50 females aged 8-21 y by using hydrodensitometry (%BFd) and a bioelectrical-impedance analyzer (%BF-BIA). The sample population was racially heterogeneous, though predominantly of African origin. Percent body fat was computed from density by using an equation derived specifically for blacks. The BIA predicted %BF with r2 = 0.77 (SEE = 3.7%BF), underestimating by a mean of 1.7%BF. Residuals (%BFd - %BF-BIA) were normally distributed but were significantly correlated with age (P less than 0.01), although this effect was small. The theoretical bases for impedance analysis and for hydrodensitometry would appear for different reasons to impair applicability of these techniques to the present population and age group. However, for our population sample the BIA estimated %BF as precisely as other simple techniques applied to other populations.

Adipose Tissue↗
PubMed1989

Antithyroid drugs in the treatment of hyperthyroidism of Graves' disease: long-term follow-up of 434 patients. Scottish Automated Follow-Up Register Group.

A study of antithyroid drug (ATD) therapy with a mean follow-up period of 10 years (range 2-25) in 434 patients with Graves' disease has been made by linking hospital records with those of a central follow-up register. The majority (89%) were treated with carbimazole and 87% received combined therapy with triiodothyronine (T3) (73%) or thyroxine (T4) (14%). Sixty-one per cent were assessed for T3 suppression tests on completion of treatment, of whom 61% (95% CL, 55-67%) suppressed. The overall 5-year cumulative proportion developing recurrent hyperthyroidism was 54-62% with rates of 26-44% in suppressed patients and 65-79% in those not suppressed. In unsuppressed patients, most (72%) of the recurrences occurred within 1 year with only an additional 10% predicted up to 10 years. In suppressed patients 30% of recurrences occurred in the first year, 60% between 1 and 5 years and a further 10% between 5 and 10 years. Suppression with T3 is probably the best and cheapest predictor of outcome but has an accuracy of only 70% for both positive and negative tests which limits its usefulness in planning long-term follow-up and surveillance. A standard format should be adopted for the analysis and reporting of follow-up studies, based on actuarial methods of estimating the cumulative proportion with recurrences or other events, to facilitate comparisons between different centres.

Adult↗
PubMed1979

Structure and dynamics of neural network oscillators.

Techniques are given to represent oscillating neural networks by asynchronous logical switching networks, and to analyze the oscillating networks using a directed graph called a state transition diagram. Consideration is restricted to network oscillators containing no rhythm determining pacemaker neurons, and no neurons exhibiting self-limiting properties such as post-inhibitory rebound or accumulating refractoriness. In the state transition diagrams, stable oscillations are associated with a particular geometric configuration called a cyclic attractor (the heavy cycle in Fig. 2). We show that given the network connectivity it is possible to predict autonomous dynamic behaviour, as well as behaviour following hyperpolarizing or depolarizing inputs to neurons of the network. Conversely, given information about patterns of firing activity during cycles and transients of neural networks, the network connectivity can be predicted. The theoretical techniques can be used to generate a census of network structures capable of generating stable oscillations. Several representative network oscillators are discussed in the context of previous theoretical and experimental studies of the structure of neural network oscillators. Although the number of theoretically possile network oscillators capable of generating sustained oscillations is very large, the techniques which are given should be useful in the design of experiments capable of distinguishing between equally plausible hypotheses.

Action Potentials↗
PubMed1979

A system for storage and retrieval of individual cells following flow cytometry.

A system has been developed to deposit cells in indexed locations on a gelatin-coated film following flow cytometry, allowing the measurements made of individual cells to be correlated with observed morphology or with subsequent microspectrophotometric measurements. Samples are deposited in a continuous track on the film by a deposition nib attached to the flow system below the observation point; laminar flow is preserved by adjusting the tape speed and the flow velocity. Locations of individual cells are indicated by etching the film with a spark triggered by the detection of a cell in the flow cytometer. After deposition, the film is dried by forced warm air. Cells on gelatin may be washed and restained with Papanicolaou and other stains with reasonable preservation of morphology. The system may be used for validation of automated cytodiagnostic procedures based on flow cytometry and for biomedical research.

Cytological Techniques↗
PubMed1979

A comparison of analgesic effectiveness of oral butorphanol/acetaminophen, oxycodone/acetaminophen and placebo in hospitalized postsurgical patients.

One hundred four patients with moderate to severe postoperative pain participated in a double-blind study comparing butorphanol/acetaminophen with oxycodone/acetaminophen and placebo with respect to analgesic effectiveness and incidence of side effects. Pain was rated by the patients and an observer; sums of these data were calculated. Side effects, their severity and their relationship to the drug were recorded. Both active medications provided statistically significant levels of analgesia as compared with placebo. Analgesia produced by both combinations of drugs was statistically similar until 4 hours postdrug. From 4 to 6 hours postdrug, butorphanol/acetaminophen was significantly more analgesic. Both active medications produced analgesia within 0.5 hours, showing a peak effect at 1 to 2 hours and lasting for 6 hours. The incidence of side effects was minimal and statistically equivalent for each treatment group.

Acetaminophen↗
PubMed1979

Butorphanol/acetaminophen double-blind study in postoperative pain.

An oral butorphanol/acetaminophen (4 mg/650 mg) combination product was evaluated for analgesic activity in 120 postoperative patients employing a double-blind experimental design. The combination product was significantly (p less than 0.05) superior to either butorphanol (4 mg) or acetaminophen (650 mg) as well as placebo. Except for acetaminophen which was only significantly different (p less than 0.05) from placebo at 2 hours according to pain relief, all other treatments were superior to placebo over the entire 4 hour observation period. The data demonstrate that butorphanol and acetaminophen have at least additive analgesic activity with a suggestion of synergism. A single tablet dose of the combination product (butorphanol 2 mg/acetaminophen 325 mg) was evaluated in a second study involving 60 patients and was significantly (p less than 0.05) superior to placebo. Both studies demonstrate that the butorphanol/acetaminophen combination product has potent analgesic activity with a minimal side effect profile.

Acetaminophen↗
PubMed1978

Evidence for thyroidal secretion of 3,3',5'-triiodothyronine in man and its control by TSH.

Thyroidal secretion of 3,3',5'-triiodothyronine (reverse T3, rT3) and its control by TSH was assessed by measuring (1) arterio-venous hormone gradients in patients undergoing surgery, (2) changes of hormone concentrations after induction of anaesthesia, and (3) changes induced by TRH administration. In ten patients in whom thyroid activity was under TSH control (parathyroidectomy and non-toxic goitre) increased thyroid vein/carotid artery ratios (TV/CA) for rT3 (mean TV/CA ratio 2.53) were found when compared to six patients with non-toxic goitre on suppressive doses of T4 (mean TV/CA ratio, 1.27) (P less than 0.05). The mean calculated operative secretion rate of rT3 was 12.5 microgram/day but only 2.4 microgram/day in patients receiving T4. In thirteen patients undergoing elective surgery induction of anaesthesia significantly increased rT3 levels. In nine euthyroid adults intravenous TRH (200 microgram) increased peripheral venous rT3 levels between 3 h (P less than 0.005) and 8 h (P less than 0.05) after the injection. It is concluded that significant amounts of rT3 are secreted by the thyroid gland at operation and this is, in part, under TSH control.

Adult↗
PubMed1977

Barbiturates and serum calcium in the elderly.

In a retrospective study, based on a biochemical survey of people aged 65 and over in a general practice, subjects taking a barbiturate preparation for indications other than epilepsy had a significantly lower serum calcium concentration than did those taking nitrazepam or diazepam. Ordinary doses of barbiturate may adversely affect vitamin D metabolism in the elderly.

Aged↗
PubMed1977

Double-blind placebo controlled oral analgesic comparison of butorphanol andpentazocine in patients with moderate to severe post-operative pain.

A double-blind, randomized trial was conducted in 120 post-surgical patients to evaluate the oral analgesic activity of butorphanol tartrate (4 mg and 8 mg) and pentazocine HCl (50 mg) as compared to placebo. Both dose of butorphanol as well as pentazocine proved to be significantly (p less than 0-05) more effective than placebo. Butorphanol 4 mg and pentazocine 50 mg were never significantly different from each other, while butorphanol 8 mg was significantly beeter than both butorphanol 4 mg as well as pentazocine 50 mg in several instances, demonstrating a significant dose effect relationship for butorphanol. All of the active treatment provided maximum pain relief within 1 to 2 hours and were effective over 4 hours. In contrast to the other treatments, none of the 8 mg butorphanol patients required remedication during the 4-hour observation period. Generally, the incidence fo side-effects appeared low.

Adolescent↗
PubMed1976

Bioluminescent countershading in midwater animals: evidence from living squid.

Midwater squid respond to overhead illumination by turning on numerous downward-directed photophores; they turn off the photophores when overhead illumination is eliminated. The squid are invisible when the intensity of the photophores matches the intensity of the overhead illumination. These results strongly support the theory of ventral bioluminescent countershading.

Decapodiformes↗
PubMed1975

Patterns and bilateral coordination of scaphognathite rhythms in the lobster Homarus americanus.

The bilateral patterns of forward and reversed scaphognathite (SG) pumping are described for the American lobster. During forward pumping the two SGs usually function synchronously, but may also function independently. The nine muscles of one SG are arranged into four functional groups which are sequentially active during forward pumping. During reversed beats, motor neurones to one group of muscles are inactive while bursts to another are either delayed or missing. Reversal beats do not appear to alter the phasing of the central oscillators that generate the basic SG rhythm. Phase analysis of bilateral SG beating demonstrates two types of relationship: phase coupling or phase drifting with a tendency to couple. An animal may remain in one state for long periods of time or may alternate between states. Coupling can occur at more than one phase indicating phase multistability. The coupled state may remain constant at markedly different frequencies of beating, indicating phase rather than latency coupling between SGs. During the drifting state each SG tends to assume its "intrinsic" rate of oscillation. The drift state reflects the inherent asymmetry of the two SG systems. The influence of several parameters of sensory stimulation on phase and frequency of SG beating are analyzed.

Action Potentials↗