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Biomedical subjects

M G Robinson

Publications and source records attributed to M G Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1984

Management of reflux esophageal disease.

Although frequent or prolonged exposure of the esophageal mucosa to gastric contents results in epithelial damage, it is also becoming clear that the pathophysiology of reflux esophageal disease may be multifactorial. The severity of this disease may relate to the frequency of reflux episodes, certainly to the duration of mucosal exposure to refluxed material, and probably to as yet unquantified factors of mucosal resistance and the specific noxiousness of refluxed gastroduodenal and pancreatic secretions. The phenomenon of esophageal clearance is a critical determinant in preservation of mucosal integrity, and a disturbance in this function may lead to severe signs and symptoms of reflux esophageal disease. A detailed analysis of the specific pathophysiologic abnormalities in individual patients may permit more "tailored" therapeutic approaches and more favorable results.

Bethanechol Compounds↗
PubMed1984

Effect of sleep on swallowing, esophageal peristalsis, and acid clearance.

Recent studies have shown that impaired esophageal clearance of refluxed material during the sleeping interval plays a major role in the pathogenesis of esophagitis. The present investigation compares esophageal responses to both acid and water infusions during sleep in asymptomatic subjects. Fourteen healthy individuals were studied. The subjects were studied for two nights in the sleep laboratory. Each night involved four to six infusions of 15 ml of either sterile water or 0.1 N HCl. A similar infusion was conducted during the presleep waking interval. Acid clearance time was shown to decrease as a function of increasing wakefulness during the acid clearing interval. Arousal responses were significantly greater with acid infusions during sleep (p less than 0.05). Awakenings from sleep with acid infusions were associated with significantly greater swallowing rates than those associated with water infusions (p less than 0.01). Peristaltic parameters of amplitude, velocity, and duration were not differentially affected by acid versus water infusions or by sleep versus waking.

Adult↗
PubMed1983

Intractable diarrhea in children with VIP-secreting ganglioneuroblastomas.

This paper describes two children with diarrhea, hypokalemia, and VIP-secreting ganglioneuroblastomas, and includes further evidence that VIP is the cause of the loose stools among patients with such tumors. It suggests that the level of this peptide should be measured in pediatric patients with intractable diarrhea of unknown etiology. Clinicians have long recognized intractable diarrhea as an occasional feature of neuroblastoma, ganglioneuroblastoma or ganglioneuroma. Until recently catecholamine was thought to cause the frequent stools in some patients with these tumors. New radioimmunoassay methods, the identification of new hormones and hormone-like substances, and the discovery that some of the tumors which cause diarrhea secrete Vasoactive Intestinal Peptide (VIP), make it probable that this substance is responsible for the diarrhea in such patients.

Child, Preschool↗
PubMed1982

Hypertensive peristalsis in the pathogenesis of chest pain: further exploration of the "nutcracker" esophagus.

The recently described "nutcracker esophagus" is associated with hypertensive peristaltic contractions and clinical complaints of chest pain and/or dysphagia. This report describes our experience with a group of 28 patients meeting the manometric and clinical criteria for this esophageal motor disorder, and it includes a specific comparison of contractions in the proximal and distal esophagus. Mean lower esophageal sphincter pressure, peak peristaltic pressures, mean peristaltic pressures, and contraction durations were all significantly elevated in the patient group. Using similarly radially oriented transducers, the amplitudes of peristaltic contractions in the distal esophagus were shown to be significantly greater in the patients than in an asymptomatic control group. No significant peristaltic differences were found between patients and controls in the proximal esophagus. These data support the existence of nutcracker esophagus as an identifiable esophageal motor disorder with several specific divergences from esophageal peristaltic parameters in controls.

Adult↗
PubMed1981

Acid clearance during sleep in the pathogenesis of reflux esophagitis.

Impaired esophageal clearing of refluxed gastric contents during sleep has been implicated in the pathogenesis of reflux esophagitis. To more directly evaluate this hypothesis, 13 symptomatic patients with esophagitis and 13 normal controls had 15 ml of 0.1 N HCl instilled into the esophagus in the recumbent position while awake and during polygraphically monitored sleep. When sleep was maintained for the majority of the acid-clearing duration, the clearance times for both patients and controls were significantly prolonged when compared to those while awake (P less than 0.01). However, when sleep was maintained for less than 50% of the acid-clearing interval, the patients showed significantly longer acid clearance times. The swallowing rate did not differentiate the two groups under any condition. These data show that sleep impairs esophageal acid clearance. Acid clearance occurred predominantly in association with arousals from sleep. The defective acid clearance found in patients with esophagitis probably plays a major role in the pathogenesis of this disorder.

Adult↗
PubMed1980

Chronic subclinical ovine fascioliasis: plasma glutamate dehydrogenase, gamma-glutamyl transpeptidase and aspartate aminotransferase activities and their significance as diagnostic aids.

The effect of low grade chronic Fasciola hepatica infection on the concentration of plasma glutamate dehydrogenase (GD), gamma-glutamyl transpeptidase (gamma-GT) and aspartate aminotransferase (AST) was investigated in sheep dosed daily with three (AL3), eight (AL8) or 14 (AL14) metacercariae over 22 weeks or given a single dose of 200 metacercariae. Significant increases in plasma GD activity first occurred after nine, 12 and 23 weeks and in gamma-GT activity after 12, 24 and 32 weeks for groups AL14, AL8 and AL3 respectively. Changes in AST activity were not as clearly related to dose level. In sheep with single infection, both GD and gamma-GT were capable of detecting liver damage resulting from the migration of 10 or more flukes. Plasma GD and gamma-GT activities are more sensitive indicators of liver cell damage in chronic subclinical fascioliasis than AST activity and gamma-GT may be more suitable as a diagnostic aid on account of its greater stability.

Animals↗
PubMed1978

Aplastic anemia associated with bone marrow suppressor T-cell hyperactivity: successful treatment with antithymocyte globulin.

In five patients with idiopathic aplastic anemia, the colony-forming unit (CFU-c) assay was used to quantitate stem cells and test the possible presence of suppressor cells inhibiting bone marrow differentiation. All five marrows failed to form CFU-c. In one out of the five cases tested, coculture of the patient's marrow with normal marrow suppressed the latter to form CFU-c. Removal of T-cells from the patient's bone marrow freed the aplastic marrow to produce more colonies and, in the coculture study, abrogated its inhibitory activity on the normal bone marrow. Treatment of the patient with horse antihuman thymocyte globulin (ATG), improved the peripheral blood count and myelopoiesis. Furthermore, the aplastic marrow increased its colony forming capacity from less than 1% pre-ATG to 46% post-ATG of the normal control, and its inhibitory activity on the normal marrow was ablated. In selected cases of aplastic anemia, with evidence of T-suppressor cell hyperactivity, treatment with ATG may offer an alternative approach to bone-marrow transplantation.

Anemia, Aplastic↗