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Biomedical subjects

J Gibbs

Publications and source records attributed to J Gibbs.

At least 127 records · Page 7Linked to original sources

Video EEG telemetry using an ambulatory EEG cassette recorder.

A system of video/EEG monitoring is described which is complementary to out-patient ambulatory EEG recording and prolonged hospital admission for intensive assessment. An ambulatory EEG cassette recorder is incorporated in the system which increases the usefulness of this equipment. In addition all the recorded EEG may be rapidly reviewed. This system has proved valuable in the management of selected patients seen in a special clinic for epilepsy.

Electroencephalography↗

Taste and eating disorders.

Taste responses to sucrose and fat-containing stimuli were examined in a population of young women with eating disorders. Anorectic-restrictor and anorectic-bulimic patients were compared with normal-weight bulimic patients and with normal-weight control subjects. Sensory estimates of sweetness and fat content of 20 different mixtures of milk, cream, and sugar did not differ among subject groups. In contrast, relative preferences for sugar vs fat as determined by the Response Surface Method differed between patients with eating disorders and control subjects. Normal-weight bulimic patients preferred sweeter stimuli than did control subjects. Anorectic-restrictor and anorectic-bulimic patients liked sweet but disliked high-fat stimuli and showed elevated optimal sugar:fat (S:F) ratios. This pattern of response did not change following weight regain. The stability of preference profiles suggests that taste responsiveness may be independent of diagnostic categories, bulimic behaviors, or acute changes in body weight.

Adolescent↗

The effect of gut peptides on hunger, satiety, and food intake in humans.

A number of peptides synthesized and secreted by gastrointestinal cells have been shown to possess significant effects on food intake and on perceptions of hunger and satiety in humans. In this paper, we review the available literature on these effects and emphasize the current obstacles for the therapeutic application of peptides to the problem of obesity.

Appetite↗

A double-blind controlled trial of high dose methylprednisolone in patients with multiple sclerosis: 2. Laboratory results.

Laboratory measurements were compared in paired samples from 50 patients included in a double-blind placebo controlled trial of methylprednisolone in the treatment of multiple sclerosis. Cerebrospinal fluid total cell count, IgG and C9 indices, and percentage of peripheral blood OKT8 positive cells were abnormal at entry and returned closer to the normal range after active than placebo treatment, but the differences were not statistically significant. The percentage of peripheral blood OKT4 positive cells was normal at entry as was the amplitude of visual evoked potentials, whereas their latency was prolonged; these measurements were each uninfluenced by methylprednisolone. Corticosteroids might act merely by influencing oedema, but the laboratory results suggest that methylprednisolone affects immunological events which underly rapid onset and recovery of symptoms in patients with multiple sclerosis; additional forms of treatment are needed to maintain these clinical and immunological effects.

Adolescent↗

Infusion of CCK-8 into hepatic-portal vein fails to reduce food intake in rats.

If the putative satiating effect of endogenous cholecystokinin (CCK) is produced through a circulating hormonal mechanism, then administration of exogenous CCK into the hepatic-portal vein should decrease meal size. To test this, one form of endogenous CCK, the C-terminal octapeptide CCK-8, was infused intraportally in doses of 4 and 8 micrograms/kg just prior to a test meal. Neither dose decreased food intake after intraportal infusion even though intraperitoneal administration of 4 micrograms/kg CCK-8 decreased meal size approximately 50% in the same rats. The results suggest that if endogenous CCK-8 has a satiating effect, it acts primarily through a paracrine mechanism.

Animals↗

Pancreatic glucagon and bombesin inhibit meal size in ventromedial hypothalamus-lesioned rats.

The effects of intraperitoneal injections of pancreatic glucagon and bombesin on meal size were tested in female rats in the dynamic phase of ventromedial hypothalamic (VMH) hyperphagia. Both pancreatic glucagon (100-2500 micrograms/kg) and bombesin (4-16 micrograms/kg) inhibited meal size in a dose-related manner. Percent inhibitions of meal size in VMH-lesioned and control rats did not differ significantly. These results suggest that the VMH is not necessary for peripheral administration of either pancreatic glucagon or bombesin to elicit postprandial satiety.

Animals↗

Intraduodenal infusions of fat inhibit sham feeding in Zucker rats.

Intraduodenal infusions of Intralipid in concentrations of 0.125 kcal/ml to 1 kcal/ml inhibited sham feeding of lean and obese Zucker rats significantly. The inhibitory potency of the fat infusions on sham feeding in both genotypes was a function of the concentration of Intralipid infused. The inhibition of sham feeding by Intralipid infusions was accompanied by the specific sequence of behaviors that characterizes satiety. Evidence supporting differential effectiveness of intraduodenal fat in producing satiety in obese and lean rats was equivocal. A conservative interpretation is that obese rats are not less sensitive than leans to the satiating potency of intraduodenal fat. We conclude that previously reported differences in the satiating potency of fats for obese and lean Zucker rats are not likely to be mediated by small intestinal mechanisms.

Animals↗

D-2 selective receptor antagonists suppress sucrose sham feeding in the rat.

Dopamine receptor blockade by pimozide has previously been shown to reduce the intake of pellets and of a sweet solution by intact, food-deprived rats and to reduce the sham intake of sucrose solutions by food-deprived rats with an open chronic gastric fistula. To determine if this effect was due to the blockade of the D-2 subclass of dopamine receptors, we investigated the effects of the selective D-2 receptor antagonists sultopride and (-)-sulpiride as well as the effects of the preferential D-2 receptor antagonists, haloperidol and pimozide, on sucrose sham feeding. All four neuroleptics administered intraperitoneally decreased the sham intake of a 10% sucrose solution significantly. The relative inhibitory potencies of these drugs for decreasing the sham intake of 10% sucrose were similar to their relative potencies for binding striatal D-2 receptors in vitro, namely HALOPERIDOL greater than or equal to PIMOZIDE much greater than SULTOPRIDE greater than or equal to (-)-SULPIRIDE. Additional evidence for the specificity of these effects was that the less active isomer (+)-sulpiride did not inhibit sham feeding of sucrose and that a dose of pimozide and of haloperidol which decreased sham feeding of sucrose after food deprivation did not decrease sham drinking of water after water deprivation. Taken together, these data support the hypothesis that dopaminergic activation of a central D-2 receptor mechanism is necessary for the positive reinforcing effect of sucrose that maintains sham feeding.

Amisulpride↗

Tumour growth delay as a clinical endpoint for the measurement of radiation response.

Tumour growth delay has been investigated as an endpoint of radiation effect in selected patients with superficial metastases measured by calipers and ultrasound. Of 42 patients referred for study with two or more nodules, 17 were suitable for entry into protocols evaluating single or multifraction treatment. The reproducibility of tumour growth delay to the same dose schedule was evaluable in four patients and the sensitivity to 10-20% differences in total dose was evaluable in three patients. No significant size dependency was detected in the response of nodules to radiotherapy and the findings suggest that the growth delay endpoint is sensitive to 20% differences in radiation dose. Evaluable patients with multiple measurable nodules are uncommon but constitute a valuable resource for the testing of biological response modifiers, including radiosensitizers.

Breast↗

Satiety: the roles of peptides from the stomach and the intestine.

Rats were surgically prepared to allow perfusions of anatomically limited portions of the gastrointestinal (GI) surface during test meals. The results demonstrated that at least one potent satiety signal was generated when ingested food accumulated in the stomach and did not enter the small intestine. This gastric satiety signal did not require the vagus nerve for its operation. In addition, at least one other potent satiety signal was generated when food perfused the small intestine. This intestinal satiety signal did not require gastric distension for its operation. We tested a variety of GI peptides to determine whether any met the criteria imposed by this evidence for regionally specific satiety signals. Bombesin (BBS), a peptide present in high concentration in the stomach, was a potent and behaviorally specific inhibitor of food intake. Its satiating effect was not altered by subdiaphragmatic vagotomy. Cholecystokinin (CCK), a peptide hormone that is released from the small intestine by food, was also a potent and behaviorally specific inhibitor of food intake; its satiating effect did not require gastric distension for its expression, but its satiating effect was markedly reduced or abolished by subdiaphragmatic vagotomy. Thus, BBS and CCK may mediate at least part of the satiating effect of food acting in the stomach and in the small intestine, respectively.

Animals↗

Effect of bombesin on feeding behavior.

Peripherally-administered bombesin and gastrin-releasing peptide produce potent, dose-related, and specific reductions of food intake at test meals in rats. Similar effects on meal size are observed after intraperitoneal injections in mice and after intravenous infusions in baboons and humans. The mechanism for this effect is unknown, but the action of bombesin is not blocked by complete subdiaphragmatic vagotomy, by a variety of peripheral endocrine and neural ablations, or by lesions of the area postrema or hypothalamus. Hypothalamic injections of bombesin produce small but specific reductions of food intake; the relationship of this central effect to the peripheral effect of the peptide is unknown. Bombesin and bombesin-like peptides may play roles in the regulation of meal size.

Animals↗

Satiety responses in eating disorders.

Appetite and satiety responses in a test meal paradigm were studied in six anorexia nervosa patients (four had bingeing and purging behaviors) and in nine normal control women. The anorexic patients were distinguished from normal controls by the amounts of food taken and by the pattern of the hunger and fullness responses to the test meal. Possible explanations for these findings are discussed.

Anorexia Nervosa↗

The satiety effect of cholecystokinin. Recent progress and current problems.

Since the discovery of the satiety effect of CCK in 1973, progress has been made and problems have been encountered. The progress has included the accumulation of strong, indirect evidence that exogenous CCK acts in the abdomen to activate vagal afferent fibers and that exogenous CCK may be useful in the treatment of bulimia and obesity in humans. The most pressing problem is the current lack of evidence for the hypothesis that the satiety effect of exogenous CCK reveals a physiological function of endogenous CCK released by food entering the small intestine during a meal. Since clarification of this problem and exploitation of the current progress seem possible with current ideas and techniques, the satiety effect of CCK should continue to receive considerable experimental attention.

Animals↗

A study of cerebral blood flow and metabolism in epileptic psychosis using positron emission tomography and oxygen.

Data are presented on four groups using positron tomography and 15 O inhalation. Compared to age-matched volunteer controls, epileptic patients show regions of low blood flow and hypometabolism as found in previous studies. Epileptic psychotic and non-psychotic patients have been compared, and the main differences noted were lower rOER in the psychotic group, especially in frontal, temporal and basal ganglia regions. When a group of psychotic patients receiving neuroleptic drugs was compared to those free of these medications the rOER was higher in the treated sample, and the rCBF fell, significantly in some areas. These data are discussed in the light of other reports of positron tomography in psychosis.

Antipsychotic Agents↗