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Biomedical subjects

J M Rhoads

Publications and source records attributed to J M Rhoads.

10 recordsLinked to original sources
PubMed1992

L-glutamine with D-glucose stimulates oxidative metabolism and NaCl absorption in piglet jejunum.

To explore the relationship between intestinal fluid absorption and oxidative metabolism, we measured the effects of amino acids and glucose on piglet jejunal ion transport and oxygen consumption (QO2) in vitro. Jejunal QO2 was stimulated by L-glutamine and D-glucose but not by the nonmetabolizable organic solutes methyl beta-D-glucoside or L-phenylalanine. QO2 was maximally enhanced by the combination of D-glucose and L-glutamine (5 mM). Even though 5 mM L-glutamine was previously found to be insufficient to stimulate NaCl absorption, 5 mM L-glutamine enhanced jejunal NaCl flux when combined with equimolar mucosal D-glucose. Either D-glucose or methyl beta-D-glucoside caused an increase in short-circuit current (Isc), an increase in Na+ absorption in excess of Isc, and a decrease in Cl- secretion, when L-glutamine was substituted for D-glucose (10 mM) on the serosal side. This relationship suggests that mucosal sugars, if combined with L-glutamine, enhance neutral NaCl absorption as well as electrogenic Na+ flow. (Aminooxy)acetate, an inhibitor of alanine aminotransferase, abolished the stimulation of QO2 and the NaCl-absorptive response to L-glutamine. We conclude that the oxidative metabolism fueled by L-glutamine is linked to a NaCl-absorptive mechanism in the intestine. We propose that the CO2 produced by glutamine metabolism yields carbonic acid, which dissociates to H+ and HCO3-, which may stimulate parallel antiports in the apical membrane.

Absorption↗
PubMed1991

L-glutamine stimulates jejunal sodium and chloride absorption in pig rotavirus enteritis.

Rotavirus enteritis is the leading cause of diarrhea in infants worldwide. A research priority of the World Health Organization is to develop oral rehydration solutions containing amino acids or other additives that will stimulate intestinal absorption more efficiently than the current glucose-based oral rehydration solutions. Glutamine is the principal metabolic fuel of the small bowel and a putative stimulator of mucosal repair. This report describes the transport response to mucosal L-glutamine following intestinal injury caused by porcine rotavirus. Peak symptoms and mucosal damage were observed 2-7 days after oral rotavirus inoculation. In vitro transport studies of the maximally injured region, the midjejunum (80% reduction in lactase), surprisingly, showed transport responses to L-glutamine (30 mmol/L) and L-alanine (30 mmol/L) that were similar qualitatively and quantitatively to those observed in control tissue. Subsequent application of mucosal D-glucose (30 mmol/L) caused additional stimulation of electrogenic Na+ transport, but the response to glucose was blunted (P less than 0.05) in the infected tissues. Glutamine and alanine enhanced Na+ absorption to a similar degree (2-2.5 muEq.cm-2.h-1), but glutamine stimulated equal amounts of electrogenic and electroneutral NaCl absorption, whereas alanine had no significant effect on net Cl- flux. Glutamine is a potentially useful substrate for investigation in oral rehydration solutions for infant diarrhea.

Alanine↗
PubMed1991

Hemorrhagic colitis and pseudomelanosis coli in ipecac ingestion by proxy.

This report describes a toddler with chronic diarrhea, vomiting, and hypotonia due to surreptitious administration of syrup of ipecac by his mother (Munchausen's syndrome by proxy). Several features of this case distinguish it from previous reports of chronic ipecac ingestion in childhood: the development of grossly bloody stools; radiologic, endoscopic, and biopsy evidence of a chronic moderate colitis resembling ulcerative colitis; and the histologic finding of pseudomelanosis coli, providing an important clue to toxic ingestion. The significance and possible mechanism for genesis of pseudomelanosis coli is discussed. This case emphasizes the variability in presentation and difficulty in diagnosing long-term ipecac ingestion by proxy. Ipecac toxicity should be considered in children with unexplained colitis and vomiting.

Biopsy↗
PubMed1979

Brief reactive psychosis: a psychodynamic interpretation.

The diagnosis "brief reactive psychosis" leaves little implied in the way of etiology or treatment approach. Three case histories are presented to illustrate the term, followed by brief summaries of the major dynamics involved. The older diagnostic term "hysterical psychosis" is discussed, and a parallel is drawn between this form of brief reactive psychosis and others so that they may be psychodynamically understood and that treatment may be rationally based upon this model.

Adult↗
PubMed1977

Overwork.

Overwork, ie, working beyond one's endurance and recuperative capacities, may be a hazard in certain personality types engaged in open-ended occupations. Some persons appear to lack an inner "governor" and for various reasons ignore the commonplace signs that inform one of the need for rest or recreation. If they are engaged in occupations that do not have a finite workday, they may at times exceed their bodies' ability to recover. Clusters of symptoms may then develop, some of which may mimic serious physical ailments. Treatment depends on diagnosing the extent of illness and eliciting the underlying causes. Correction involves enforced rest, therapy that may vary from counseling to hospitalization and specialized treatment, but that must include the reeducation of the person to be aware of and make provision for his physical and emotional needs.

Adult↗
PubMed1976

Host-range properties of murine xenotropic and ecotropic type-C viruses.

Host-range properties of xenotropic (x-tropic) and ecotropic mouse type-C viruses were determined. NB-tropic viruses replicated only in mouse and rat cells, whereas x-tropic viruses, which do not exogenously infect mouse cells, grew in cells from various other mammalian species. Great variability in susceptibilities to x-tropic viruses was demonstrated in cells from heterologous species and in cells from a single species (human). Although rat cells were susceptible to both types of viruses, hamster cells were uniformly resistant. In addition, the x-tropic viruses crossed class barriers to infect cells of avian species but not insect, fish, or reptile cells.

Animals↗