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Biomedical subjects

C Wright

Publications and source records attributed to C Wright.

At least 343 records · Page 19Linked to original sources
PubMed1985

Polyamines as mediators of the effect of prolactin and growth hormone on the growth of N-nitroso-N-methylurea-induced rat mammary tumor cultured in vitro in soft agar.

This study evaluated the role of polyamines in mediating the effect of ovine prolactin (oPRL) and ovine growth hormone (oGH) on the growth of the N-nitroso-N-methylurea [(NMU) CAS:684-93-5]-induced rat (Sprague-Dawley) mammary cancer cultured in soft agar. oPRL and oGH had a dose-related growth-promoting effect when added to NMU-induced mammary tumors cultured in soft agar in the absence of serum. The effect of oPRL and oGH was blocked by alpha-difluoromethylornithine (DFMO), a suicide inhibitor of ornithine decarboxylase, the rate-limiting enzyme of polyamine biosynthesis. Exogenous administration of polyamines reversed the inhibitory effect of DFMO and completely restored the action of oPRL and oGH. Our results indicated that polyamines are essential in mediating the growth of the NMU-induced mammary tumor under these experimental conditions.

Agar↗
PubMed1985

Computer-aided nursing diagnosis for community health nurses.

The computer program described in this article was primarily designed to be an aid in the clinical reasoning process. It is intended to simplify the use of nursing diagnoses in the practice of community health nursing. However, in its present form, this program has value not only for the clinician, but also for nursing students being taught structured techniques for assessment. A more comprehensive approach to nursing care and the routine use of nursing diagnoses in providing that care will be encouraged. This article questions the necessity for community health nurses to use computers in their diagnostic role. In answering this question, evidence has been presented that both describes some of the benefits of using computer technology as it relates to nursing diagnoses, and the results of efforts by nurses who have experimented with this technology in trying to improve their practice. One of the advantages of trying to merge a new technology with a relatively new role for community health nurses is the absence of tradition. There is no traditional methodology or approach for integrating the two. And, there is no one to say that it cannot be done. An approach can be tried, changed if it does not work, and tried again. An opportunity to create a new dimension for professional practice is offered. The answer, therefore, to the opening question is, "Yes--community health nurses should be concerned with using computers in their diagnostic role."

Artificial Intelligence↗
PubMed1984

Effect of partial agonist activity in beta blockers in severe angina pectoris: a double blind comparison of pindolol and atenolol.

The use of beta adrenoceptor blockade in the treatment of rest angina is controversial, and the effects on severe angina of partial agonist activity in beta blockers are unknown. Eight patients with effort angina and seven with effort and nocturnal angina and severe coronary artery disease were studied initially when they were not taking any antianginal drugs. Pindolol 5 mg thrice daily (with partial agonist activity) and atenolol 100 mg daily (without partial agonist activity) were given for five days each in a double blind randomised manner. Diaries of angina were kept and treadmill exercise testing and ambulatory ST monitoring performed during the last 48 hours of each period of treatment. Daytime and nocturnal resting heart rates and the frequency of angina were significantly reduced by atenolol compared with pindolol (p less than 0.01). The duration of exercise was significantly increased and the frequency, duration, and magnitude of daytime and nocturnal episodes of ST segment depression on ambulatory monitoring were reduced by atenolol. Reduction in resting heart rate is important in the treatment of both effort and nocturnal angina. Partial agonist activity in beta adrenoceptor antagonists may be deleterious in patients with severe angina pectoris.

Adrenergic beta-Agonists↗
PubMed1984

Choice, as opposed to latency, measures in avoidance suggest that vasopressin and oxytocin do not affect memory in rats.

Latency measures from passive avoidance studies are frequently used as an index of memory. Thus, vasopressin (VP) is thought to enhance memory, since it has been shown to increase re-entry latencies. Conversely, several substances, such as oxytocin (OT), are supposed to have amnestic effects since they may decrease latencies. We describe a novel avoidance design, which allows latency to be assessed, but also permits the animal to re-enter into a distinctive compartment where shock had not been experienced (choice measure). Latency scores indicated that VP may improve memory, but the choice index suggested that this was not the case.

Animals↗
PubMed1984

N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) affects locomotor activity without producing a nigrostriatal lesion in the rat.

Drug addicts abusing heroin substitutes contaminated with N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and perhaps those who work with this substance, may develop symptoms similar to those seen in Parkinson's disease [7, 12, 13]. We describe the results of a study in which rats were given daily injections of MPTP for two weeks. A progressive suppression of activity was seen, but the subjects rapidly recovered when treatment ceased. The animals were then injected with D-amphetamine or apomorphine; the former drug enhanced activity, to levels seen in control (non-MPTP treated) subjects. Apomorphine had no effect, either on control or MPTP-treated subjects. The effects of acute (0, 2.5, 5.0 and 10.0 mg per rat) administration of MPTP were also studied. The two lower doses significantly decreased activity, but the highest dose did not. Histological examination showed that 2 weeks' treatment with MPTP did not produce neuronal degeneration in the pars compacta of the substantia nigra (SN). In these animals, there were no changes in levels of dopamine, 5-hydroxytryptamine, or their metabolites in either the SN or the caudate nucleus. MPTP had no effect on the levels of neurotensin, somatostatin and substance P in several brain areas. It is concluded that MPTP has reliable effects on locomotor activity in rats without producing measurable histological or neurochemical changes in the nigrostriatal dopaminergic system.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1984

Cigarette smoking and the treatment of angina with propranolol, atenolol, and nifedipine.

To determine whether cigarette smoking affects the results of drug treatment for angina, we studied 10 cigarette smokers with angina who were given placebo, nifedipine (60 mg per day), propranolol (240 mg per day), and atenolol (100 mg per day), each for one week. The four-week double-blind study was repeated with the same randomly determined order of drug sequences, after all 10 subjects had stopped smoking. Before and after the subjects stopped smoking, all three drugs significantly reduced the frequency of angina, as measured with angina diaries, and improved the results of maximal exercise testing and 48-hour ambulatory monitoring of ST segments (P less than 0.01). However, during the nonsmoking phase of the study, there was an overall decline in the frequency of angina and an improvement in performance on exercise testing (P less than 0.05) as compared with the smoking period, although the results of 48-hour ambulatory monitoring remained unchanged. The improvement after patients stopped smoking was greater during treatment with nifedipine than during administration of the other two drugs or placebo. Blood levels of propranolol were increased when patients stopped smoking; levels of nifedipine and atenolol were unchanged. Our data show that smoking had direct and adverse effects on the heart and interfered with the efficacy of all three anti-anginal drugs, but with nifedipine the most.

Angina Pectoris↗
PubMed1984

Comparison of the clinical significance of methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolations.

A prospective study of the incidence and clinical significance of Staphylococcus aureus isolations in patients undergoing surgery in a 600-bed hospital has disclosed that methicillin-sensitive organisms are more likely to be associated with severe infections (36%) than methicillin-resistant organisms (26%), and that resistant organisms are present as a colonization more often (54%) than sensitive organisms (42%). However, once a severe infection has become established, that with a methicillin-resistant organism is associated with an increased length of stay in hospital, and a greater risk of death.

Aged↗
PubMed1984

Polyamines as mediators of estrogen action on the growth of experimental breast cancer in rats.

The role of polyamines as mediators of the mitogenic effect of 17 beta-estradiol (E2) was investigated in the N-nitrosomethylurea [(NMU) CAS: 684-93-5; N-methyl-N-nitrosourea]-induced Sprague-Dawley rat mammary tumor grown in the soft agar clonogenic assay under serum-free medium conditions. Inhibition of polyamine biosynthesis with alpha-difluoromethylornithine (DFMO) (1 mM), an irreversible inhibitor of ornithine decarboxylase, completely blocked the growth-promoting effect of E2 (10(-8) M) in this system. Exogenous administration of putrescine (2.5 mM), spermidine (0.1 mM), and spermine (0.1 mM) reversed the inhibitory effect of DFMO and completely restored the action of E2. These polyamines, however, had no effect on tumor growth when they were added alone in identical concentrations. The results indicate that polyamines are essential but probably not sufficient in mediating the E2 effect on the growth of the NMU-induced mammary tumor under these experimental conditions.

Animals↗
PubMed1984

The interaction of cigarette smoking and beta-adrenoceptor blockade.

The importance of the interaction between smoking and propranolol (metabolised in the liver) and atenolol (excreted almost entirely in the urine) was investigated in a double-blind placebo-controlled trial. Resting and exercise heart rates were significantly greater during smoking than no-smoking phases. Atenolol and propranolol significantly improved ST segment response after exercise whether or not the patients were smoking. Plasma propranolol significantly increased when patients stopped smoking whereas there was no such change in atenolol levels.

Adrenergic beta-Antagonists↗
PubMed1984

Inability of the ST segment/heart rate slope to predict accurately the severity of coronary artery disease.

Analysis of the ST segment/heart rate slope during exercise testing has been suggested as a method of accurately predicting the presence and severity of coronary artery disease. Exercise tests were performed in 78 patients presenting with the chest pain to determine the maximum ST segment/heart rate slope. In 21 (27%) patients the ST segment/heart rate slope could not be calculated in any electrocardiographic lead. In the remaining 57 (73%) patients the maximum ST segment/heart rate slope accurately predicted the presence or absence of coronary disease in 44 patients (sensitivity 90%, specificity 40%). In addition, the extent of coronary disease was accurately predicted in 24 patients (sensitivity 42%). Thus the maximum ST segment/heart rate slope did not perfectly predict either the presence or the severity of significant coronary artery disease.

Adult↗
PubMed1984

Acquired pulmonary stenosis due to pleomorphic adenocarcinoma.

Acquired pulmonary stenosis was diagnosed in a 53 year old woman presenting with the unusual feature of an oral murmur. Mediastinotomy showed extensive malignant tissue surrounding the pulmonary artery, although a mediastinal mass was not evident on chest radiographs. Histological examination confirmed a pleomorphic adenocarcinoma, which has not previously been reported as causing acquired pulmonary stenosis.

Adenocarcinoma↗
PubMed1984

Reversal of the antiproliferative effect of the antiestrogen tamoxifen by polyamines in breast cancer cells.

Numerous studies suggest a relationship between the action of hormones on their target tissues and the synthesis of polyamines. To evaluate the role of polyamines in the mediation of the effect of estrogen on the growth of experimental hormone-responsive mammary cancer, we investigated whether the cytotoxic effect of the antiestrogen tamoxifen could be rescued by exogenous administration of polyamines. When added to N-nitrosomethylurea-induced mammary tumors grown in soft agar in the presence of tamoxifen, putrescine, spermidine, and spermine were able to reverse the inhibitory effect of antiestrogens on colony formation in a dose-dependent fashion. In contrast, no effect on colony number was observed when polyamines were added in the absence of tamoxifen. These results indicate that in this system, the antitumor effect of tamoxifen is mediated through induction of polyamine depletion. Consequently, the data suggest that estrogens may stimulate mitogenesis of the N-nitrosomethylurea-induced mammary tumor through the polyamine pathway.

Animals↗
PubMed1984

Managing stable angina pectoris: nitroglycerin, beta blockers and risk factor reduction.

Angina pectoris is the presenting complaint in a significant number of clients with atherosclerotic cardiovascular disease, and indicates potentially lethal sequelae. This article reviews the definition and etiology of stable angina pectoris, including reversible risk factors often associated with the disease. It also describes trends in behavioral and pharmacological approaches to management and outlines a management plan for the nurse practitioner who, after the initial medical workup, can assume the role of primary health care provider in long term follow-up of stable angina pectoris clients.

Adrenergic beta-Antagonists↗
PubMed1984

A social-ecological assessment and feedback-intervention of an adolescent treatment agency.

This research project examined the utility of one of Moos's Social Ecology Scales as applied to a community-based, adolescent treatment facility. Real and Ideal forms of the Community Oriented Program Environment Scale (COPES) were administered to the staff and clients at two separate facilities of the same adolescent service agency. Comparisons of the social ecological profiles of the two facilities revealed anticipated differences in the perceived levels of administrative order and control. Perceptions of the environment, however, were not found to correlate with independent measures of satisfaction or with individual-difference variables. Feedback of the survey findings to the staff members provided them with useful insights in changing program activities. These findings are discussed in light of the extant literature on the use of survey-feedback designs within organizational settings. Suggestions for future research in adolescent treatment environments are offered.

Adolescent↗
PubMed1983

Treatment of angina pectoris with nifedipine: importance of dose titration.

The effects of different doses of nifedipine on frequency of angina and objective measurements of myocardial ischaemia during exercise were studied in 10 patients with stable angina pectoris. In a single blind trial over nine weeks patients received one week's treatment each with placebo, nifedipine 10 mg, 20 mg, 30 mg, 40 mg, 30 mg, 20 mg, 10 mg, then placebo three times a day. The response to the different doses of nifedipine was highly variable. On exercising, three patients achieved a consistent improvement in workload attained before onset of ST segment depression and maximum ST depression during exercise testing during all active phases. Four patients improved with 10 mg three times a day but deteriorated at higher doses. In two patients there was no objective or subjective improvement with any dose of the drug, while in one patient anginal frequency increased and there was objective deterioration during exercise testing at doses above 10 mg three times a day. Thus a dose of nifedipine that is beneficial in one patient may have minimal or opposite effects in another. These results indicate the importance of careful titration of doses for individual patients if the maximum benefit from nifedipine is to be obtained in patients with exertional angina.

Adult↗