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Biomedical subjects

C Wright

Publications and source records attributed to C Wright.

At least 307 records · Page 17Linked to original sources
PubMed1987

Epstein-Barr-virus-related malignant B cell lymphoplasmacytic lymphoma following allogeneic bone marrow transplantation for aplastic anemia.

The development of B cell lymphoma has been reported to occur in recipients of a variety of organ transplants, including some patients who have received an allogeneic bone marrow graft. In this report, we describe a patient with severe aplastic anemia who developed a malignant B cell lymphoplasmacytoid proliferation 48 days after undergoing allogeneic marrow transplantation from her HLA-matched MLC-nonreactive brother. Immunologic studies showed this malignancy to be a mixed polyclonal and monoclonal proliferation in donor cells. Virologic studies documented Epstein Barr infection of the cells. A review of the literature suggests that graft-versus-host disease and treatment of this complication by antithymocyte globulin are related to the development of the EBV-related malignancy in the EBV-infected B cells of the developing bone marrow graft.

Adult↗
PubMed1987

Diurnal variation in left ventricular function: a study of patients with myocardial ischaemia, syndrome X, and of normal controls.

Angina can occur in the early morning. The mechanism of this is unclear and both haemodynamic changes and coronary artery spasm may be important. The purpose of this study was to investigate the diurnal variation in pulmonary artery diastolic pressure (an indirect measure of left ventricular filling pressure) in six normal subjects, 18 patients with coronary artery disease, five with variant angina, and six with syndrome X. A transducer tipped catheter and a simple recording system were used to record ambulatory pulmonary artery diastolic pressure for 24 hours. Variation in pulmonary artery diastolic pressure was related to the timing of episodes of ST segment depression and elevation by simultaneously recording a frequency modulated electrocardiogram. Episodes of ST segment change occurred predominantly in the early morning (midnight to 6 am) in variant angina (eight out of 14 episodes) whereas in syndrome X all episodes were recorded during the day. In coronary artery disease both painful and painless episodes were distributed throughout the day, with 10 out of 67 episodes occurring between midnight and 6 am. A similar diurnal variation in pulmonary artery diastolic pressure was seen in the groups--that is, values were low during the day and higher at night, with the maximum values between midnight and 6 am. The 24 hour median pulmonary artery diastolic pressure was higher in patients with coronary artery disease than in the control group and those with syndrome X. The finding that pulmonary artery diastolic pressure, and therefore left ventricular end diastolic pressure, is greatest in the early morning may represent the background haemodynamic state in which other factors lead to myocardial ischaemia during these hours.

Adult↗
PubMed1987

Treatment of angina pectoris with nifedipine: a double blind comparison of nifedipine and slow-release nifedipine alone and in combination with atenolol.

The relative efficacy of nifedipine and slow-release nifedipine (Adalat Retard) in the treatment of stable exertional angina pectoris was evaluated in a double blind randomised crossover study in eight patients on no concomitant antianginal treatment and in 10 patients who were additionally on atenolol. Patients were assessed by angina diaries and exercise testing. Slow-release nifedipine was as effective as nifedipine in the treatment of these patients, both alone and in combination with atenolol.

Angina Pectoris↗
PubMed1987

Refresher education policy: results of a survey.

Occupational Therapy experiences chronic manpower shortage. This is in part, due to loss of trained,experienced manpower. In many cases, female occupational therapists, like other women, drop-out of the work force to re-enter later. In an attempt to delineate refresher education policy for re-entering, a mail survey of randomly selected members of Ontario occupational therapists and occupational therapy managers was conducted. The results of the survey suggested refresher education should be mandatory after an absence of 3-5 years, should be under the jurisdiction, at least in part, of the provincial association, should be oriented to specialists training and have a variety of formats including clinical practice.

Data Collection↗
PubMed1987

A combined study of cortisol, ACTH and dexamethasone concentrations in major depression. Multiple time-point sampling.

The pathophysiology of hypercortisolaemia in major depression was examined. ACTH was measured using a novel immunoradiometric assay of high specificity and sensitivity. Twenty-eight patients with major depression and 18 control subjects were studied. Blood samples for basal hormone concentration were taken at 09:00, 16:00 and 23:00 on day 1, followed by administration of 1 mg dexamethasone at 23:00. Further samples were taken at 09:00 and 16:00 on day 2. Dexamethasone concentration was measured in day 2 samples and no significant difference was found between the depressed group and control subjects. In the depressed group cortisol concentration was elevated at 23:00 on day 1, and ACTH concentrations were elevated in post-dexamethasone samples. ACTH and cortisol concentrations were not directly correlated in individual patients. The elevated plasma cortisol associated with major depression is not solely mediated by changes in ACTH.

Adrenocorticotropic Hormone↗
PubMed1987

Using nursing model to affirm Catholic identity.

Religious sponsors such as the Franciscans must develop an approach that reaffirms their mission goals in today's technological, competitive health care environment. The Neuman Systems Model, originally designed to help nurses incorporate values in their practice, offers a way to achieve this goal. This model provides a clearly defined system that identifies the client as a total person and a classification of stressors that all health team members can apply. It is compatible with such Catholic traditions as the Franciscans because of its: Holistic, systems approach; Emphasis on person as client; Inherent flexibility. According to the model, the client is a unique composite of physiological, psychological, sociocultural, developmental, and spiritual variables and has a central structure surrounded by lines of defense and resistance. Health care providers can use primary, secondary, or tertiary preventions, depending on the client's degree of reaction to stressors. Health care facilitates the client's system stability or harmony through either attainment or maintenance of optimal wellness. With this model and their mission values, religious institutes can develop creative ways to respond to client needs in an increasingly bureaucratic and business-oriented environment.

Catholicism↗
PubMed1987

Hypertension and the ischaemic myocardium.

Hypertension and ischaemic heart disease often co-exist. Recent studies, using ambulatory ST-segment and haemodynamic monitoring, have shown that myocardial ischaemia may not necessarily be accompanied by angina pectoris. Unless transient myocardial ischaemia is actively sought it may, therefore, be missed and this may have important prognostic and therapeutic implications. Studies investigating the use of beta-blockers, calcium antagonists and nitrates in angina pectoris have shown that these agents have an equal effect on painless as opposed to painful myocardial ischaemia. While there are no currently completed studies demonstrating the prognostic implication of silent ischaemia in stable angina, it is well known that approximately one-quarter of all myocardial infarctions occur without chest pain. Recent investigation in unstable angina showed that silent ischaemia was an important predictor of future coronary events.

Coronary Disease↗
PubMed1987

Reproducibility of results in "near-replicate" carcinogenesis bioassays.

Reproducibility of results was examined in 70 "near-replicate" comparisons consisting of 2 or more long-term carcinogenesis bioassays of the same chemical administered by the same route and using the same sex and strain of rodent. Overall, there was good reproducibility of positivity, target site, and carcinogenic potency in hamsters, mice, and rats. The published authors' opinions about whether the test was positive disagreed in only 9 of the 70 comparisons. Among the 35 comparisons in which all tests of the chemical were positive, 33 of the near-replicates had at least 1 identical target site. The carcinogenic potency values estimated from near-replicate tests in these 35 comparisons were within a factor of 2 of each other in 40% of the comparisons, within a factor of 5 in 80%, and within a factor of 10 in 90%. For the few cases in which the carcinogenic response was not reproduced, analyses suggest two explanations: In mice the discrepant cases tended to have shorter experiment times than average; in both rats and mice the discrepant results tended to be tests of weakly active compounds.

Animals↗
PubMed1987

Vaginal müllerian stromal sarcoma. A case report.

Primary malignancies of the vagina are among those encountered most rarely in the female reproductive tract. Even more rare are primary vaginal sarcomas. The fourth case of vaginal müllerian stromal sarcoma is reported on here.

Aged↗
PubMed1986

Desamino-D-arg8-vasopressin (DDAVP), unlike ethanol, has no effect on a boring visual vigilance task in humans.

It has been suggested that vasopressin (VP) and its analogues such as desamino-D-arg8-vasopressin (DDAVP) affect cognitive (including mnemonic) and attentional processes in man. We describe the effects of DDAVP and ethanol (EtOH) on young, healthy human volunteers, using a recently developed visual search task which assesses attention and vigilance. Over a 1-h session, the subject has to detect the occurrence of certain digits in a long list of random characters. A low dose of EtOH (0.33 ml/kg) tended to improve, and a higher dose (1.0 ml/kg) disrupted performance. DDAVP (20 or 60 micrograms/subject) had no effect whatsoever. It is concluded that intranasal administration of the peptide analogue does not markedly affect attention performance in human subjects.

Anxiety↗
PubMed1986

Estrone sulfate: a potential source of estradiol in human breast cancer tissues.

Local formation of estradiol in human breast tumors could provide a more important source of estrogen than is delivered from plasma. Prior studies have suggested that estrone is primarily synthesized from estrone sulfate. The enzyme 17 beta-hydroxysteroid dehydrogenase (HSD) would be required to convert estrone to estradiol. This study characterized HSD in 1000 X g supernatants from human breast tumors. Estradiol synthesis was linearly related to tissue concentration or time over the range studied. Cofactor requirements varied with estrone concentration. High and low affinity sites were found in 50% of tissues studied, while the remainder contained only low affinity sites. Screen assays showed measurable activity in all 42 samples tested. This activity ranged from 0.73- greater than 100 nmol estrone synthesized/g protein/hr, with a median activity of 5.9 nmol/g/hr. We evaluated the biological relevance of the sulfatase-HSD pathway by testing the ability of estrone sulfate to stimulate colony formation in soft agar cultures of nitrosomethylurea-induced rat mammary tumors. The maximally effective concentration ranged from 10(-7) to 10(-4)M. Significant stimulation of colony formation was observed in 7 of 8 experiments. The estrone sulfate stimulation pattern was similar to that previously observed with estradiol. Of the 3H-estrone sulfate added to the dishes, 20-98% was recovered as estrone and 0.2-6% as estradiol. These studies suggest that the requisite enzymes are present in human breast tumors for conversion of estrone sulfate to estradiol, and that this pathway may be biologically significant.

17-Hydroxysteroid Dehydrogenases↗
PubMed1986

The incidence and morphology of ischaemic ventricular tachycardia.

Ventricular arrhythmias are a frequent cause of sudden death in patients with coronary artery disease. The incidence and relationship of ventricular tachycardia to periods of myocardial ischaemia in these patients has not been fully investigated. Ambulatory ST-segment monitoring was performed in 100 consecutive patients with chest pain, of whom 74 had significant coronary artery disease. Recordings were analysed for ST-segment changes and episodes of ventricular tachycardia (greater than 3 beats, rate greater than 100 beats min-1). None of the 26 patients with normal coronary arteries, one of the 22 patients (4.5%) with single vessel disease, one of the 22 patients (4.5%) with double vessel disease and four of the 30 patients (13%) with triple vessel disease, had episodes of non-sustained ventricular tachycardia. Four of these six patients had episodes of reversible ST-segment change but ventricular tachycardia was related to these episodes in only two patients. These two patients had multiple episodes of tachycardia which occurred after the onset of ST-segment change and terminated before the ST-segment returned to baseline; they occurred in clusters with a mean of 12 episodes in each cluster. ST-segment change did not follow episodes of ventricular tachycardia in any patient. The number of ventricular complexes in each episode varied between three and 24 beats and were uniform in three of the six patients. The mean heart rate before the onset of tachycardia was 79 +/- 8 beats per minute and the rate of tachycardia had a mean of 170 +/- 34 beats a minute. Less than 10% of the episodes had a prematurity index of less than 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1986

Enzymatic control of estrogen production in human breast cancer: relative significance of aromatase versus sulfatase pathways.

One-third of the cases of breast cancer in postmenopausal women are hormone-dependent and the lesions regress upon treatment with antiestrogens or inhibition of estrogen biosynthesis. In these patients, estrogens are synthesized in extraglandular tissues from adrenal precursors and re-enter plasma to produce estrone levels of 52 +/- 6.5 pg/ml (mean +/- SEM) and estradiol concentrations of 13.1 +/- 0.7 pg/ml. However, the fact that the levels of estrogen in breast tumor tissue are an order of magnitude higher than plasma levels suggested the possibility of in situ estrogen production. To address this possibility, we measured several enzymes involved in estradiol biosynthesis in human tumors. Forty-eight of 61 tumors contained aromatase (estrogen synthetase) activity ranging from 5-80 pg/gm protein per hour. By comparison, the levels of estrone sulfatase were 10(6) higher, ranging from 0.8-125 micrograms/gm protein per hour. Because the sulfatase enzyme was of lower affinity (i.e., Km = 27 microM) than that of aromatase (i.e., 0.027 microM), the amount of estrogen formed under conditions of similar substrate concentrations was compared and found to be 10-fold higher via the sulfatase enzyme. In 41 additional tumors, the 17 beta-hydroxysteroid dehydrogenase enzyme, catalyzing the conversion of estrone to estradiol, was uniformly present. To test the biologic relevance of the estrone sulfate to estrone to estradiol pathway, estrogen-dependent nitrosomethylurea rat mammary tumors were grown in soft agar in the presence of estrone sulfate. Concentrations of estrone sulfate of 10(-6) microM significantly (p less than 0.01) stimulated colony formation in this system in which 75.5-98.6% of estrone sulfate was converted to estrone and 0.2 to 6% to estradiol. These data support the hypothesis that mammary carcinomas can synthesize estradiol in situ from circulating estrogen precursor and that local conversion is biologically important. On the basis of comparative data, the estrone sulfate to estrone to estradiol pathway is quantitatively more important than that involving androstenedione to estrone to estradiol.

17-Hydroxysteroid Dehydrogenases↗
PubMed1986

Continuous ambulatory pulmonary artery pressure monitoring. A new method using a transducer tipped catheter and a simple recording system.

A transducer tipped catheter and simple recording system were used for the continuous measurement of ambulatory pulmonary artery pressure. The pulmonary artery pressure was recorded on a miniaturised tape recorder and replayed via an optical writer. Pulmonary arterial systolic and diastolic pressures can be analysed on a beat to beat basis. Continuous ambulatory monitoring was performed for a total 288 hours in 13 patients who were undergoing routine investigation for coronary artery disease. There was less than 1% zero drift and 0.25% linearity error per full scale pressure. The frequency response of the entire system was flat to 8 Hz with a linear phase delay. The transducer tipped catheter and a conventional fluid-filled system were used to measure left ventricular and pulmonary artery end diastolic pressures in eight patients. The correlation between the results obtained by the two methods was excellent. This method could be used at any centre equipped for ambulatory electrocardiographic monitoring.

Adult↗
PubMed1986

Haemodynamic response to myocardial ischaemia during unrestricted activity, exercise testing, and atrial pacing assessed by ambulatory pulmonary artery pressure monitoring.

Ambulatory pulmonary artery pressure monitoring by means of a transducer tipped catheter with a simultaneous frequency modulated electrocardiogram and a miniaturised tape recorder was used to study the haemodynamic implications of ST segment depression in patients with coronary artery disease. Nineteen male patients (mean (SD) age 58 (11) years) with clinical and angiographic evidence of coronary artery disease were studied together with six controls. Changes in the ST segment and pulmonary artery diastolic pressure during treadmill exercise, atrial pacing, and unrestricted ambulant activity were analysed. During exercise, pulmonary artery diastolic pressure rose significantly in patients with coronary artery disease but not in the controls. One patient with ST depression greater than 1 mm did not have a rise in pulmonary artery diastolic pressure on exercise; two had a rise in pulmonary artery diastolic pressure with no ST segment change despite severe angina. The pulmonary artery diastolic pressure tended to rise before or simultaneously with the onset of ST segment depression. The haemodynamic response to atrial pacing was similar in normal controls and patients with coronary artery disease. During ambulatory monitoring there were 29 episodes of ST segment depression all of which were associated with a rise in pulmonary artery diastolic pressure and chest pain. The onset of ST segment depression occurred before a rise in pulmonary artery diastolic pressure in 11 episodes, was simultaneous with it in 11, and followed it in seven episodes. During exercise and ambulatory monitoring there was a correlation between the magnitude of ST segment depression and the rise in pulmonary artery diastolic pressure. Pain was a late feature during exercise, atrial pacing, and anginal episodes. This technique for the first time allows the relation between ST segment changes and haemodynamic alterations in left ventricular function to be assessed in ambulant patients with coronary artery disease.

Aged↗