Search PubMed⌕ Search

Biomedical subjects

M Morris

Publications and source records attributed to M Morris.

At least 289 records · Page 16Linked to original sources
PubMed1992

Central and systemic oxytocin release: a study of the paraventricular nucleus by in vivo microdialysis.

The mechanisms controlling central and systemic oxytocin (OT) release were examined using in vivo microdialysis of the paraventricular (PVN) region. Dialysate and plasma samples were collected from conscious male rats and stimuli were administered via the dialysate fluid. Characterization studies showed that microdialysis was a viable technique for the study of peptide secretion in the conscious animal. OT was consistently detected in the PVN dialysate and a partially purified extract crossreacted in parallel fashion with the synthetic peptide. In vitro studies showed that peptide recovery was positively correlated with the pore size of the dialysis membrane and that there was an inverse relationship between flow rate and recovery. Hypertonic saline administered centrally caused an increase in dialysate and plasma oxytocin while the intravenous injection affected only plasma oxytocin. The excitatory amino acid, glutamate (0.05-0.5 M), caused an increase in plasma, but not dialysate oxytocin, while depolarization with potassium chloride (0.05-0.15 M) had no significant effects. Histological examination showed that the dialysis probe was located in the rostral, lateral PVN. Our results show that in vivo microdialysis provides a method for the delivery of drugs into specific brain regions as well as a useful technique for the evaluation of in vivo neuropeptide release.

Analysis of Variance↗
PubMed1992

Transport considerations for the head-injured patient: are we contributing to secondary injury?

The association between an improved prognosis and early treatment, including surgical intervention, makes air transport for the head-injured patient an important component of care. Patient positioning and the use of hyperventilation have been modes of treatment used for decreasing cerebral edema and ICP for many years. This standard of care should be emphasized during air medical transport as well.

Aircraft↗
PubMed1992

Primary treatment failure in patients with malignant ovarian germ cell neoplasms.

Between 1970 and 1990, 160 patients with malignant non-dysgerminomatous ovarian germ cell tumors have been treated at our own institution. Primary therapy failed in 42 of these patients, who constitute the basis for this study. Seventeen patients had stage I disease, 5 stage II, 17 stage III, and 3 stage IV. Histologic type included 13 immature teratomas, 8 endodermal sinus tumors, and 21 mixed germ cell tumors. Primary therapy for 14 patients was surgery alone, for 23, surgery plus chemotherapy, for 2, surgery plus radiotherapy and for 3, all three modalities. Median progression-free survival from initial diagnosis lasted 6.8 months (range, 0.9-24 months). Thirty-four patients received chemotherapy as part of salvage; 5/11 (45%) who received VAC are disease-free, and 6/11 (55%) who received cisplatin combinations are disease-free. When primary VAC failed, 3/7 (43%) were salvaged with cisplatin combinations. When primary cisplatin combinations failed, 2/5 (40%) were salvaged. Twelve of the 42 patients (29%) are currently alive disease-free. Primary treatment failure was attributed to surgery alone for 14 patients (7 because of misdiagnosis), radiotherapy for 5, and toxicity for 1. Of the 22 patients who failed chemotherapy, 12 did so because of a suboptimal regimen, 3 because of possible dose-intensity problems, one because of non-compliance, and 6 for unexplained reasons. Patients with ovarian germ cell tumors have an excellent probability of cure with aggressive primary therapy, but successful salvage may be difficult when primary treatment fails.

Journal Article↗
PubMed1992

When loyalties are divided between teachers and patients.

Three situations are described where a junior doctor is required by his consultant to do something that he thinks is not in the patient's best interests. The dilemma is explored from the perspective of patients' interests being the doctor's first concern; of the importance of respect for medical teachers, and of the implications of an apprenticeship model of postgraduate medical training.

Consensus↗
PubMed1992

Alterations in oxytocin prohormone processing during early development in the fetal sheep.

Oxytocin (OT) prohormone processing was studied in fetal sheep. Using specific antisera that recognize the amidated and the COOH-terminal extended forms of OT, we measured arterial and venous levels of the OT peptides in fetal sheep plasma at 94 and 138 days of gestation. Plasma levels of the COOH-terminal extended forms, OT-X, were highest early in development, 35.7 +/- 9.8 vs. 14.3 +/- 5.7 pg/ml (94 vs. 138 days). The ratio of the plasma peptides, OT-X to OT, was higher in the young fetus (35 +/- 11.6 vs. 3.1 +/- 1.3, 94 vs. 138 days). There were also developmental changes in the umbilical artery-umbilical vein differences, with positive values noted in late gestation. These results demonstrate that the changes in the processing of the OT precursor that occur during fetal development are reflected by alterations in the relative amounts of prohormone and amidated hormone found in fetal plasma.

Animals↗
PubMed1992

Sinoaortic denervation does not increase cardiovascular/endocrine responses to stress.

Sinoaortic baroreceptor denervation is reported to produce exaggerated centrally derived cardiovascular and endocrine responses. We examined the effect of sinoaortic denervation (SAD) on the cardiovascular and endocrine responses to two acute stressors, footshock and immobilization, in male Sprague-Dawley rats. Parameters measured were mean arterial pressure (MAP), heart rate (HR) and plasma levels of oxytocin (OT) and vasopressin (VP). Baseline MAP was elevated in the SAD group (approximately 25 mm Hg) and footshock stress increased arterial pressure equivalently in both groups. This stress caused tachycardia and increased plasma OT, with a tendency for the SAD group to show blunted responses. Immobilization increased HR but caused no change in MAP and no significant difference between the groups. This form of stress also increased plasma OT, and again the SAD group showed a diminished response. Plasma VP was not significantly altered by either stressor. The results of these studies indicate that SAD does not uniformly increase the cardiovascular and endocrine responses to all stressors or centrally derived stimuli. These results also suggest that the lack of an increase in plasma VP is not related to baroreceptor-mediated inhibition of secretion under stressful conditions.

Animals↗
PubMed1992

Presymptomatic testing for Huntington's disease in Wales 1987-90.

Between 1987 and 1990 a large series of at-risk individuals has been referred to our Huntington's disease (HD) presymptomatic testing programme. A detailed protocol for assessment and counselling has been followed. Out of 238 serious inquiries, 36% were potentially suitable for the testing programme, but 19% chose not to continue. Reasons for exclusion included the presence of clinical features of HD and being under the age of 18 years. Out of 40 final results given to 38 individuals, 23 indicated a lowered risk, 11 an increased risk, while five results were uninformative, two of these becoming informative on repeat testing. This series contained more women than men, and was disproportionately from the higher socio-economic groups. Motives for requesting a test principally related to child-bearing, informing existing children, and planning for the future. No significant psychiatric symptoms have been reported in the short term, but difficult counselling problems were presented by the high proportion of applicants who already showed clinical signs of HD. It is concluded that a detailed counselling protocol is essential in testing for HD, as many applicants are ill-prepared; this will assume even greater importance when the HD gene is identified and a test for specific mutations is available. The experience of presymptomatic testing for HD provides important general lessons which are likely to be applicable to other inherited neurological and psychiatric disorders.

Adaptation, Psychological↗
PubMed1992

The ABCs of DRGs.

Explore the source record for details and available documents.

Abstracting and Indexing↗
PubMed1992

Reasons for inappropriate simple hysterectomy in the presence of invasive cancer of the cervix.

We evaluated 148 women who had had simple hysterectomy in the presence of invasive cervical cancer between the years 1973-1987. Two had microinvasive squamous carcinoma for which hysterectomy was not a planned procedure. The remaining 146 women all had either adenocarcinoma or squamous carcinoma exhibiting greater than 3 mm of stromal invasion of lymph-vascular space involvement. Medical records were reviewed retrospectively to determine the reasons for hysterectomy. Causes of inappropriate hysterectomy were as follows: inadequate evaluation of an abnormal Papanicolaou smear or cervical biopsy (21%), failure to perform an indicated conization (12%), deliberate hysterectomy for grossly invasive cancer of the cervix (11%), lack of preoperative Papanicolaou smear (7%), conization margins positive or not evaluated (7%), misreading of pathology results (5%), emergent operation because of bleeding (3%), failure to check cytology preoperatively (1.5%), and failure to biopsy a gross cervical lesion (1.5%). The remaining 31% of cases had normal or inflammatory Papanicolaou smears and negative cervical examinations. Although 93% of this latter group complained of abnormal bleeding, 78% did not have endocervical or endometrial sampling preoperatively. Despite the increasing emphasis on cervical cancer screening, the number of referrals following hysterectomy performed in the presence of cervical carcinoma is not decreasing. Most cases could be avoided by careful adherence to well-established guidelines for cervical cancer detection.

Adenocarcinoma↗
PubMed1992

Pelvic exenteration in the elderly patient.

Advanced age is frequently considered a contraindication to radical exenterative surgery. We reviewed the outcomes of 63 patients age 65 years or older who underwent pelvic exenteration between 1960-1991 at The University of Texas M. D. Anderson Cancer Center. Sixty-three percent had preexisting medical illnesses. Major or potentially life-threatening complications were noted in 38% of the patients. An additional 38% experienced minor complications. Sixty percent experienced one or more infectious complications, including pyelonephritis, wound infection, sepsis, and flap necrosis. When both major and minor complications were considered, infectious morbidity was the single largest category. Although they are not life-threatening, nonspecific infectious morbidity and transient confusion were the most frequent individual complications, occurring in 26 and 24% of patients, respectively. Twenty-four percent of the patients experienced no complications. Thirty-four percent of the postoperative survivors suffered late major morbidity. Operative mortality was 11%; multisystem failure was the most frequent cause of death. After a mean follow-up of 4 years, 22 patients were alive with no clinical evidence of disease. Twenty-one patients died of recurrent disease, with a median time to recurrence of 9.6 months. The 5-year survival rate for the group was 46%. In comparison, 363 patients younger than age 65 who underwent exenteration during the same period experienced an operative mortality rate of 8.5% and a 5-year survival rate of 45%, neither of which were significantly different from the rates found for the older group (P = .51 and .52, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Prenatal diagnosis of hereditary amyloidosis in a Portuguese family.

Portuguese-type amyloidosis is an autosomal dominant condition caused by a point mutation of the prealbumin (transthyretin) gene. The mutation can be detected directly by the presence of a restriction site for Nsil. We report the first prenatal diagnosis for this condition, performed in the first trimester by chorionic villus sampling, polymerase chain reaction, and restriction enzyme digestion.

Amyloidosis↗
PubMed1991

A lack of effect of captopril on platelet aggregation in patients with congestive heart failure.

We have studied the acute and chronic effects of an ACE inhibitor (captopril) on platelet function and the renin-angiotensin system in patients with congestive heart failure. Plasma concentrations of angiotensin II fell significantly after a single dose of captopril (25 mg) and during long-term treatment with captopril (2 weeks, 75 mg/day). Plasma renin activity increased significantly after both the single and repeated doses. Captopril did not affect ADP-induced platelet aggregation or concentrations. It seems unlikely that circulating angiotensin II affects ADP-induced platelet aggregation in patients with congestive heart failure.

Angiotensin II↗
PubMed1991

Phase II trial of carboplatin or iproplatin in cervical cancer.

From July 1984 to November 1987, 89 patients with recurrent measurable squamous-cell cancer of the uterine cervix were randomized in a single institution to receive treatment with either carboplatin (CBDCA) or iproplatin (CHIP). Objective response rates were similar: 2 complete regressions (CRs) and 10 partial regressions (PRs) were recorded both in the 46 evaluable patients treated with CBDCA (response rate, 26.1%; 95% confidence interval, 15-41%) and in the 40 evaluable patients treated with CHIP (response rate, 30%; 95% confidence interval, 17-47%). The median duration of response was 5.5 months for CBDCA and 6 months for CHIP; the median survival was 7.5 and 7.6 months, respectively. Both drugs were given in an outpatient setting and myelosuppression (thrombocytopenia) was the predominant toxicity. Analysis of all toxic events yielded additional interesting observations: the occurrence of moderate to severe platelet nadirs beyond cycle 1 was confined to CHIP, a higher incidence of gastrointestinal toxicity during treatment with CHIP, and five moderate to severe complaints of asthenia (recorded as neurologic events) during CHIP therapy versus only one during treatment with CBDCA. Because of its antitumor activity and its toxicologic advantage, a future role for CBDCA in the treatment of cervical cancer appears likely.

Antineoplastic Agents↗
PubMed1991

A log-linear modeling framework for selective mixing.

Nonrandom mixing can significantly alter the diffusion path of an infectious disease such as AIDS that requires intimate contact. Recent attempts to model this effect have sought a general framework capable of representing both simple and arbitrarily complicated mixing structures, and of solving the balancing problem in a nonequilibrium multigroup population. Log-linear models are proposed here as a general framework for solving the first problem. This approach offers several additional benefits: The parameters used to govern the mixing have a simple, intuitive interpretation, the framework provides a statistically sound basis for the estimation of these parameters from mixing-matrix data, and the resulting estimates are easily integrated into compartmental models for diffusion. A modified selection model is proposed to solve the second problem of generalizing the selection process to nonequilibrium populations. The distribution of contacts under this model is derived and is found to satisfy the assumptions of statistical inference for log-linear models. Together these techniques provide an integrated and flexible framework for modeling the role of selective mixing in the spread of disease.

Acquired Immunodeficiency Syndrome↗