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Biomedical subjects

R Robertson

Publications and source records attributed to R Robertson.

At least 109 records · Page 6Linked to original sources
PubMed1982

The epidemiology of physical activity in children, college students, middle-aged men, menopausal females and monkeys.

Although the inverse relationship between physical activity and coronary heart disease (CHD) has been well documented, little is known concerning the epidemiology of physical activity. A primary reason for the lack of knowledge has been a problem of quantification of physical activity. We have employed the Large-Scale-Integrated (LSI)Activity Monitor in five diverse populations to measure individual physical activity levels. The results indicated that the instrument can accurately index individual physical activity levels, as well as to provide important information concerning the epidemiology of physical activity.

Adolescent↗
PubMed1977

Interdependence of decompression sickness and plasma enzymes on dive profile and vitamin B-6 status.

The mortality rate due to decompression injury was found to be significantly greater in a rat population with a mild vitamin B-6 deficiency, compared to an adequately fed control group, when subjected to a bends-producing N2-O2 dive. Relative post-dive changes in lactate dehydrogenase, creatine phosphokinase, and transaminase levels in plasma do not appear to be sufficiently different to allow a ready distinction in the degree of susceptibility of one nutritionally defined population from the other.

Alanine Transaminase↗
PubMed1976

A technique of sexual counselling.

A method of sexual counselling based on the technique originally proposed by Masters and Johnson but modified to suit local conditions is described. The method is basically "client-centred" and depends on interviewing both partners of a sexually inadequate relationship so that the clients themselves set the level of desired sexual achievement. Factors which may inhibit a sexual relationship are explored, particularly those involving cultural, moral, religious, education or financial matters. Ejaculatory problems and orgasmic dysfunction are treated in the manner described by Masters and Johnson, whilst other interpersonal and communicative problems are handled by making use of Kagan's Interpersonal Recall snselling clinics are discussed.

Communication↗
PubMed1976

Effects of alcohol on ion transport by isolated gastric and esophageal mucosa.

The effects of ethyl alcohol, 20%, were measured on steady state rates of ion transport by isolated mucosa. Luminal, but not serosal, addition of alcohol altered ion transport. Alcohol caused a sustained reduction in apparent basal acid secretion by fundic mucosa. These tissues were resistant to ordinarily effective stimulants of acid secretion (histamine, theophyline, dibutyryl cyclic AMP, and gastrin) by rabbit mucosa. Across antral mucosa, net Na transport was inhibited, and net Cl transport was reduced in the presence of alcohol. The unidirectional fluxes of both ions were increased as was permeability to erythritol. These effects of alcohol did not require the presence of acid in the lumen. The rate of luminal acid loss by antrum was increased by alcohol. Addition of ouabain alone, which inhibits net Na and Cl transport, did not alter the rate of luminal acid loss by antrum. Alcohol, however, still increased the rate of luminal acid loss by antral mucosa treated with ouabain. Alcohol reduced the electrical resistance of fundic and antral mucosa but had no effect on the rate of luminal acid loss or electrical resistance of esophageal mucosa. Luminal application of alcohol inhibits active ion transport in addition to increasing cation and anion permeability. However, inhibition of active transport per se is not necessarily associated with an increase in mucosal permeability.

Animals↗
PubMed1976

Histamine effects on H+ permeability by isolated gastric mucosa.

This study examines the effects of histamine on mucosal permeability to acid by isolated stomach of rabbits. Histamine (9 X 10(-5) M) decreased antral luminal acid loss which could not be accounted for by active H+ secretion or appearance of organic acid. Histamine also increased antral electrical resistance and decreased the unidirectional luminal to serosal flux (Jls) of (14)c-erythritol. Histamine, theophylline, and N(6),O(2)-dibutyryl adenosine 3',5'-monophosphate did not significantly alter secretion by fundus in the presence of salicylate (5 X 10(-3)M). However, after removal of salicylate, these agents stimulated acid secretion. Histamine decreased luminal acid loss by both antrum and fundus treated with salicylate, increased the electrical resistance of these tissues, and decreased Jls erythritol of fundic mucosa. Burimamide (1 X 10(-3) M) inhibited the permeability effects of histamine on antrum and fundus. The data indicate that histamine decreases spontaneous antral mucosal permeability as well as salicylate-induced increase in mucosal permeability of both antrum and fundus. The effects of burimamide suggest that antrum contains H2 receptor sites urelated to acid secretion and that fundus contains H2 receptor sites which also govern permeability but are independent of those related to acid secretion.

Animals↗
PubMed1975

Supportive evidence for altered platelet function in the dived rat.

A study was conducted on the changes in platelet function and platelet count in the Sprague-Dawley rat induced by a bends-producing N2-O2 compression-decompression cycle. In those instances where mild to moderate cases of decompression sickness were produced, a decrease in platelet reactivity to ADP-induced aggregation occurred immediately postdive along with an increase in inhibition of aggregation by prostaglandin E1. Both effects returned to control levels 24 hours postdive. In moderately affected animals, platelet counts were lower than normal 24 hours postdive but were similar to control values 72 hours postdive. These results tend to support current hypotheses regarding the etiological relationship between disseminated intravascular coagulation and decompression sickness as a function of bubble nucleation.

Adenosine Diphosphate↗
PubMed1975

Effect of hyperbaric helium on vitamin uptake and utilization by micro-organisms.

Growth responses under hyperbaric helium of various procaryotic micro-organisms to graded levels of six water-soluble vitamins were measured. Vitamins included: thiamin, riboflavin, niacin, pantothenic acid, biotin, and folic acid (folacin). Growth response of each organism under hyperbaric helium was compared with that under 80% He-20% O2 and other He-O2 gas mixtures at atmospheric pressure, and with response in air at atmospheric pressure. For five of the six vitamins, no differences in response were observed. Growth response of Streptococcus faecalis to growth-limiting concentrations of folic acid was depressed during cultivation under He-O2 at 69 ATA. It is concluded that growth response of the organism is repressed by hyperbaric helium as a result of interference with uptake or utilization of the vitamin.

Animals↗
PubMed1973

Neonatal jaundice and maternal oxytocin infusion.

A prospective study of 78 neonates provides evidence for an association between maternal oxytocin infusion and neonatal jaundice. On the second and fifth days infants of mothers whose labour had been induced by amniotomy followed immediately by intravenous oxytocin (group C) had mean total bilirubin levels significantly higher (P <0.05) than did infants whose mothers had had a spontaneous onset of labour and did not require oxytocin (group A). Bilirubin levels in infants of mothers whose onset of labour was spontaneous but required oxytocin to accelerate progress (group B) did not differ significantly from group A.Though these findings suggest a dose dependent effect of oxytocin, other possible explanations are suggested which take into account other drugs administered to the mother and also differences in the corticosteroid status of the groups of infants.

Bilirubin↗
PubMed1972

Modification of behavior problems in the home with a parent as observer and experimenter.

Four parents enrolled in a Responsive Teaching class carried out experiments using procedures they had devised for alleviating their children's problem behaviors. The techniques used involved different types of reinforcement, extinction, and punishment. One parent increased the frequency of the wearing of an orthodontic device during five daily time checks by making an immediate monetary payoff contingent on wearing the device. A second parent increased the number of points earned for doing daily household tasks by providing back-ups for which the points could be exchanged. The parents of a 4-yr-old boy decreased the frequency of whines, cries, and complaints by removing social attention when such behavior occurred. A mother decreased the duration of time it took for her 5-yr-old daughter to get dressed by making permission to watch television contingent on dressing within 30 min of the time she got up in the morning. Brief reversals of contingencies were used to show causal relationships between the procedures used and the changes in behavior. Checks on the reliability of measurement were made by persons present in the home.

Journal Article↗