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N J Brown

Publications and source records attributed to N J Brown.

At least 19 recordsLinked to original sources
PubMed1992

The effect of adrenoceptor antagonists on the ileal brake mechanism in the rat.

1. Studies were carried out in the rat to investigate the effect of adrenoceptor antagonists on stomach to caecum transit time under control conditions and during ileal infusion of Intralipid. Stomach to caecum transit time (SCTT) of the head of the meal was measured by use of environmental hydrogen analysis and the distribution of the meal was assessed by a scintigraphic technique. 2. Four adrenoceptor antagonists were used in these studies, the alpha 1 antagonist prazosin, the alpha 2 antagonist, idazoxan, the beta 1 antagonist atenolol and the beta 2 antagonist ICI 118551. 3. None of the antagonists affected SCTT of the head of the meal during ileal infusion of saline. However, the alpha 1 and beta 1 antagonists significantly reversed (P less than 0.05) the delay in SCTT induced by ileal infusion of Intralipid whereas the alpha 2 antagonist, idazoxan, potentiated this delay (P less than 0.05). 4. Study of the distribution of the radiolabelled meal showed that the Intralipid delayed SCTT by slowing both gastric emptying (P less than 0.05) and small bowel transit (P less than 0.05). 5. Prazosin delayed gastric emptying under control conditions (P less than 0.001) but did not alter significantly the effect of ileal lipid on the distribution of the meal, 100 min or 200 min after gavage.6. The meal distribution was more compatible with the hydrogen analysis after administration of the ,beta-adrenoceptor antagonists. The reversal of the lipid-induced delay in SCTT caused by atenolol was associated with more radioactivity in the large intestine 200min after the gavage. ICI 118551 had no significant effects on either the distribution of the meal or the SCTT of the head of the meal.7. In conclusion, the data confirm that the sympathetic nervous system normally modulates or mediates the mechanisms that influence gastrointestinal transit in the rat and suggest that these mechanisms may be involved in the ileal brake effect. Nevertheless the data also suggest that simple measurement of the transit of the head of the meal by use of environmental hydrogen analysis may sometimes give a misleading impression of the action of drugs on gastrointestinal transit of the bulk of a test meal.

Adrenergic Antagonists↗
PubMed1992

Evaluation study of a transcultural discovery learning model.

This qualitative, descriptive study explored the extent to which students' discovery learning centered around cultural understanding and sensitivity occurs in a clinical rotation involving migrant health care. Thirteen nursing students enrolled in this community health clinical rotation were the study sample. Demographically, they were similar to other baccalaureate students in the school of nursing. Characteristics that set them apart were their levels of maturity, motivation, and independence, and their ability to cope with stress and ambiguity. Student journal entries were used to explore changes in cultural understanding and sensitivity over the course of an intensive six-week clinical experience. The method of inquiry was qualitative descriptive. Discovery learning from the perspective of the students was analyzed using domain analysis scheme. Themes that emerged from analysis of the data were personal and professional growth, specialized nursing practice roles with ethnic minorities, and health care system needs and issues for culturally sensitive care. Our findings contribute to faculty understanding of the degree to which student nurses make a transformation in terms of cultural understanding and sensitivity, and the process by which increased cultural understanding and sensitivity result in application of theoretical transcultural concepts.

Adult↗
PubMed1992

A collaborative effort between a state migrant health program and a baccalaureate nursing program.

This article reports on the way in which a unique collaborative effort between a service agency and a baccalaureate nursing program grew out of the needs of the two separate agencies. The first agency, the Colorado Migrant Health Program, was faced with a budget that was inadequate to meet the health-care needs of the migrant population. The second, a baccalaureate nursing program at the University of Colorado, was finding it increasingly difficult to locate appropriate generalized community health clinical placements with an opportunity for student discovery learning related to transcultural health care. Discussions of a collaborative effort ensued and it became evident that each had something to gain from such an effort. Now, after almost 10 years of cooperation, the commitment to the endeavor on the part of both agencies remains strong as the benefits to each continue to increase. The ultimate beneficiaries, however, are the migrant families receiving care and the students providing care. The way in which the program has evolved over time, a description of the current program, and a discussion of the resources that help to maintain the program are presented. In addition, the curriculum course design, and teaching strategy modifications necessary to facilitate the collaborative program are discussed.

Colorado↗
PubMed1992

A case of polyuria.

Explore the source record for details and available documents.

Diabetes Insipidus↗
PubMed1991

A pharmacodynamic interaction between caffeine and phenylpropanolamine.

The pharmacokinetic and pharmacodynamic interaction between caffeine and phenylpropanolamine has been investigated in six normal subjects in a double-blind, placebo-controlled, Latin-square design study. After 3 days on a 100 mEq sodium, xanthine-free diet, fasting subjects were placed in a supine position and were given 25 mg phenylpropanolamine and placebo, 250 mg caffeine and placebo, or 25 mg phenylpropanolamine and 250 mg caffeine in random order. Blood pressure, pulse, plasma renin activity, and plasma catecholamine levels were measured before and for 3 hours after drug administration. Plasma and urinary phenylpropanolamine, caffeine, and caffeine metabolite levels were measured serially for 48 hours. Coadministration of caffeine and phenylpropanolamine produced an additive increase in blood pressure. This effect could not be explained by any pharmacokinetic interaction between the two drugs and occurred even though phenylpropanolamine attenuated the epinephrine and renin response to caffeine. These data suggest that a clinically relevant interaction between caffeine and phenylpropanolamine does occur in drug-free subjects and that this interaction cannot be explained by a mechanism involving the sympathetic or renin-angiotensin systems.

Adult↗
PubMed1991

Case report: fatal pulmonary toxoplasmosis following chemotherapy.

A 41-year-old woman with acute myelomonocytic leukemia in remission died of a rapidly progressive necrotizing pneumonia while in the recovery phase following consolidation chemotherapy. Autopsy revealed disseminated toxoplasmosis. Although this syndrome has been well described to present as a neurologic complication in certain immunocompromised patients, it is rare in acute leukemia, and non-neurologic presentations are even more unusual. This case emphasizes the need to be suspicious of toxoplasmosis in immunocompromised patients even in the absence of neurologic signs or symptoms.

Adult↗
PubMed1991

The effect of a 5-HT3-antagonist on the ileal brake mechanism in the rat.

Studies have been carried out on 7 male adult rats to investigate how the action of the selective 5-HT3 receptor antagonist, granisetron, influences gastrointestinal transit under control conditions and when it is delayed by ileal infusion of lipid. Stomach to caecum transit time (SCTT) was measured using environmental hydrogen analysis. Subcutaneous administration of granisetron (BRL 43694, 40 micrograms kg-1) significantly delayed the passage of the head of the baked bean meal through the stomach and the small intestine under control conditions (P less than 0.05). The same compound, however, significantly reversed the delay in SCTT induced by ileal infusion of lipid (P less than 0.001). These apparently paradoxical results may be rationalized by postulating inhibition of receptors on afferent nerves initiating reflexes that both accelerate and delay transit.

Animals↗
PubMed1991

Short chain fatty acids in the terminal ileum accelerate stomach to caecum transit time in the rat.

We have previously shown that infusion of triglycerides and long chain fatty acids into the ileum of humans and rats delays small bowel transit time. The present studies have investigated the effect on the stomach to caecum transit time of a baked bean meal of the ileal infusion of 20 mM, 50 mM, and 100 mM acetic, butyric, hexenoic, and caprylic acids in rats. After an 18 hour fast either a control or a short chain fatty acid (SCFA) solution (pH 6.5) was infused into the ileum for 30 minutes (0.3 ml/hour). A test meal was given by gavage and the infusion continued for a further 150 minutes. The arrival of the meal in the colon was signalled by a rise in the exhaled hydrogen concentration. Acetic acid (20 mM, 50 mM, 100 mM), butyric acid (100 mM), and caprylic acid (100 mM) produced a significant acceleration of transit which was inversely proportional to SCFA chain length. In a separate experiment, infusion of 100 mM acetic acid, the most potent SCFA, into an isolated ileal Thirty-Vella loop failed to accelerate transit of the test meal. Our results suggest that SCFAs accelerate transit via a local enteric reflex.

Acetates↗