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Biomedical subjects

C Campbell

Publications and source records attributed to C Campbell.

At least 253 records · Page 14Linked to original sources

Pharmacological manipulation of adynamic ileus: controlled randomized double-blind study of ceruletide on intestinal motor activity after elective abdominal surgery.

In a double-blind placebo-controlled trial of patients undergoing elective abdominal surgery (n = 91), a single intravenous infusion of ceruletide (2.5 ng kg-1 min-1 for 1 hour) resulted in audible bowel sounds in 42/47 patients as opposed to 30/44 receiving placebo (P less than 0.025). Excessive bowel sounds were noted in 16 patients in the ceruletide group and four receiving placebo (P less than 0.01). Significantly more patients (P less than 0.01) in the ceruletide group (22/45 versus 9/44) passed flatus per rectum between the second and third post-operative day. Ceruletide infusion was accompanied by a significant increase in the incidence of nausea and vomiting (P less than 0.005, P less than 0.0025) but these side effects were short-lived. These results indicate that ceruletide is likely to be a useful therapeutic agent for acute intestinal adynamic motility disorders.

Abdomen↗

Pathophysiology of acute and chronic cardiac failure.

Cardiac (or myocardial) failure, a major health problem, can be defined using physiologic criteria that consider the adequacy of O2 delivery relative to the body's O2 requirements. In clinical terms, cardiac failure may be described in terms of its chronicity or the extent to which signs and symptoms of right- versus left-sided heart failure are dominant. Congestive heart failure is a clinical syndrome that consists of a constellation of signs and symptoms that arise from congested organs and hypoperfused tissues. Acute cardiac failure occurs because of a decrease in myocardial contractility that can be offset by the Frank-Starling mechanism. In chronic cardiac failure dilatation and myocardial hypertrophy serve to restore ventricular function. Other compensatory responses that are invoked include a salt avid kidney, which mediates an expansion of the intravascular space, and the activation of the adrenergic nervous and renin-angiotensin-aldosterone systems and an increase in circulating arginine vasopressin. The management of acute and chronic cardiac failure can be derived from an understanding of the pathophysiologic mechanisms responsible for their appearance and include improving cardiac performance, as well as the distribution of systemic blood flow to tissues based on physiologic priorities and moment to moment variations in O2 requirements.

Acute Disease↗

Low-dose vaccination against hepatitis B in children: one-year follow-up.

Six hundred forty-three children, negative for markers of hepatitis B virus (HBV) infections, were given three X 2-micrograms doses of Merck, Sharp and Dohme (MSD) plasma derived hepatitis B vaccine (H-B-Vax) at monthly intervals. Twelve months after the first dose of vaccine, antibody to hepatitis B surface antigen (anti-HBs) was detected in 89% of children by radioimmunoassay (RIA) and in 83% by enzyme immunoassay (EIA). Seroconversion rates and anti-HBs titres were significantly greater in 1-4-year-olds than in older children (p less than 0.01). Eighteen children with no anti-HBs or other markers of HBV at this time were given 10 micrograms of vaccine and tested one month later. Seventeen developed anti-HBs, 12 at levels consistent with an anamnestic response. Forty-nine HBV-marker-negative children seroconverted for antibody to hepatitis B core antigen (anti-HBc) in the 8-month period before or the 12-month period following vaccination. Forty-six of these children were positive for anti-HBs, and one has been confirmed as a chronic carrier of hepatitis B surface antigen (HBsAg). Three cases of clinical hepatitis B in children have been seen in the community since the vaccination programme began. Two of these were amongst the estimated 5% of children who were not vaccinated. The third was in a vaccinee and occurred 4 1/2 months after the last dose of vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Patients who refuse treatment in medical offices.

Five hundred sixty-two consecutive patient visits to a medical office were prospectively evaluated for the presence of ethical problems. During 23 (4.0%) visits, patients refused recommended medical intervention. Refusal was defined as the rejection of preventive health measures, diagnostic evaluation, hospitalization, and other office procedures. Preventive health measures, vaccinations, and cancer screening were the most common types of intervention refused (n = 10). Diagnostic studies, such as roentgenograms, biopsies, and cardiac stress testing were also commonly refused (n = 9). The reasons for the refusal included psychologic factors, such as fear and anxiety, previous "bad" experiences with the recommended intervention, distrust of physicians, and problems of communication. Fourteen patients suffered no major consequences from their refusal, five of whom were seen twice during the study. Five patients had a delayed diagnosis and one patient died of a myocardial infarction after refusing hospitalization for unstable angina.

Adolescent↗

Evidence that thioridazine enhances amphetamine-induced stereotypy via anticholinergic activity.

The hypothesis that the anticholinergic properties of thioridazine can account for its ability to enhance amphetamine-induced stereotyped behaviors was tested. In one experiment, scopolamine-induced repetitive head movements were shown to be potentiated by thioridazine. In another experiment, subthreshold doses of scopolamine and thioridazine interacted to potentiate amphetamine-induced repetitive head movements. The data suggest that thioridazine, in addition to its neuroleptic activity, has significant anticholinergic effects in vivo and these effects may account for its potentiation of amphetamine-induced stereotypy.

Animals↗

Rat strain differences in the acquisition of hippocampal self-stimulation.

The rate of acquisition of lever-pressing for electrical stimulation of the hippocampus (HPC) was compared in two strains of rat: barrier-sustained Wistar and Sprague-Dawley. Sprague-Dawley rats initially bar-pressed at very low rates and took a median of 11 days to self-stimulate, according to the criterion used. Wistar rats all reached the same criterion in the first test session. Differential sensitivity to the activating effects of stimulation as an explanation for this difference was ruled out by the observation that both strains decreased response rates at the same rate and to the same level if stimulation was made non-contingent on lever-pressing. Differential threshold for reward was ruled out by the observation that rate-intensity curves yielded the same threshold currents and peak rates in both strains. Finally, it was shown that the rate of development of kindled seizures in the two strains of rats is different: Wistars kindle to full seizures faster than do Sprague-Dawleys. The relationship between the quicker onset of self-stimulation and of kindled seizures in Wistars is discussed.

Animals↗

Projections of the mesencephalic locomotor region in the rat.

Retrograde labeling and electrophysiological techniques were used to determine the organization of efferent projections of the mesencephalic locomotor region (MLR) in the rat. Injections of horseradish peroxidase (HRP) or fluorescent dyes were made into suspected terminal zones of the MLR. After allowing for retrograde transport, the same animals underwent precollicular transection under anesthesia. The MLR was identified physiologically by the induction of controlled locomotion on a treadmill at low current (less than 50 microA) levels. Stimulation sites were marked and the brain processed accordingly. Retrogradely labeled cells in proximity (less than 0.5 mm) to locomotion-inducing stimulation sites were considered to be putative MLR neurons and were plotted according to stereotactic coordinates. These studies revealed the intrinsic organization of MLR neurons projecting to various brainstem sites. This organization may be related to the different types of transmitter systems involved in mediating MLR function.

Animals↗

The role of reinforcement in reactive self-monitoring.

The role of reinforcement in reactive self-monitoring was investigated. Subjects for this study were three mentally retarded adults employed in a sheltered workshop. Changes in productivity rates in a party hat assembly task across experimental conditions (reinforcements, self-monitoring, and self-monitoring plus reinforcement) were evaluated. Findings showed that while reinforcement alone increased productivity, it was to a lesser degree and with less consistency than when combined with self-monitoring. In addition, self-monitoring alone did not increase productivity. These results support the Rachlin and Nelson and Hayes hypotheses that reactive effects of self-monitoring are dependent upon environmental contingencies. The results also showed that self-monitoring increases the salience of reinforcement.

Adult↗

Baby drinks.

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Beverages↗

Being there.

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Disasters↗

The class of '85.

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Education, Nursing↗