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Biomedical subjects

R McClelland

Publications and source records attributed to R McClelland.

12 recordsLinked to original sources
PubMed1991

Hormone sensitivity in breast cancer: influence of heterogeneity of oestrogen receptor expression and cell proliferation.

The percentage of oestrogen receptor (ER) positive cells in a series of 118 breast cancers has been examined by immunohistochemistry in relation to patients' response to endocrine therapy. Positive and negative predictive values have been used to calculate appropriate cut-off points. The rate of response to treatment was significantly higher in women with receptor positive tumours, especially where the tumours contained more than 70% positive cells. Tumours that were apparently negative for ER expression rarely responded to endocrine therapy. The hormone sensitivity of ER positive breast cancer was also influenced by the rate of tumour cell proliferation, with tumours expressing high levels of Ki67 immunostaining rarely responding to therapy.

Antibodies, Monoclonal↗
PubMed1991

Relationship between the pharmacokinetics and iron excretion pharmacodynamics of the new oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one in patients with thalassemia.

Single-dose and steady-state pharmacokinetics of the new oral iron chelator, 1,2-dimethyl-3-hydroxypyrid-4-one (L1) were studied in 14 patients with thalassemia and correlated with iron excretion. Food prolongs the rate of absorption of L1, but it does not affect significantly the extent of absorption measured by the area under the plasma concentration-time curve. Similarly, it does not affect the chelation potential of the drug. The mean elimination half-life of the drug is 3 hours, suggesting that a divided dose every 8 hours may assure better chelation. Our steady-state studies reveal that urinary iron excretion is independently influenced by body iron load (measured by ferritin levels) and by steady-state trough concentrations of the drug. While patients were receiving an unchanged regimen of 75 mg/kg/day, we have detected a gradual and significant decrease in trough concentrations in the presence of unchanged patients' compliance monitored by the Medication Event Monitoring System, diaries, and pill count. These findings suggest self-induction of L1 metabolism or decreased absorption during long-term therapy. Because of the concentration-dependent iron excretion, patients may need increasing doses to achieve negative iron balance.

Adolescent↗
PubMed1990

Intra-habenular injection of 6-hydroxydopamine produces impaired acquisition of DRL operant behavior.

The anatomical connections of the habenula complex indicate it provides a relay between limbic forebrain and midbrain. Somewhat paradoxically, consequences of nonspecific lesion of the habenula are ambiguous with little change in basic response evident within simple behavioral paradigms. However, the potential functional importance for this relay has more recently been indicated by the demonstration of deficits in the ability of lesioned animals to alter behavior appropriate to both internal and external stimuli in more demanding behavioral tasks. Doubts concerning the importance of the habenula remain because of the large number of descending fibers of passage through the habenula. To provide more substantive evidence, 6-hydroxydopamine was injected into the habenula of rats to provide more limited lesion of catecholaminergic terminals. Animals were subsequently trained on an operant DRL 20-s schedule for which deficits have been reported following nonspecific lesion of the habenula. Lesioned animals showed a tendency to overrespond and were significantly less efficient on the schedule with decreased number of reinforcements received relative to controls. While the neurotoxic lesion procedure used does not differentiate noradrenergic and dopaminergic damage, the importance of intact catecholaminergic systems within the habenula for effective DRL acquisition is consistent with the suggested importance of the habenula for feedback regulation of dopamine within the ventral tegmental area through ascending dopamine fibers to the habenula.

Animals↗
PubMed1989

Improving the validity of the GHO30 by rescoring for chronicity: a failure to replicate.

To replicate the finding by Goodchild and Duncan-Jones (1985), that rescoring the GHQ30 in order to take account of chronicity would improve its validity, a random sample of 244 people completed the GHQ. Of these 102 also took part in a second interview in which they were administered the PSE. There was no evidence that the new scoring scheme improved correlations between the GHQ and other measures of morbidity nor did this improve its sensitivity or specificity when validated agaist the PSE.

Adult↗
PubMed1989

Communication skills training for medical students: an integrated approach.

Skills of communication are not easily taught to medical students. Three main clinical departments (general practice, medicine and mental health) of the Medical Faculty of the Queen's University, Belfast, introduced an integrated course in January 1988 to teach the basic principles. The course is held at the beginning of clinical training and is an integral part of the introductory clinical course. It was introduced in response to the Report of a Working Party of the Education Committee of the General Medical Council (1987) which advocated the need for improved training in history-taking and communication. It is a 12-week course and every Monday and Friday afternoon from 1400 to 1700 hours 12 students are seconded from ward work, four to the Department of Medicine, four to the Department of General Practice and four to the Department of Mental Health. Hand-outs about information to be obtained and interview style are standardized and the principles to be followed are clearly defined in an aide-mémoire. Staff from the Departments of General Practice and Mental Health experienced in teaching communication by videotape feedback and analysis of consultations prepared 12 tutors for their role and responsibilities. Procedures to be followed were carefully explained to all students beforehand. General practice and psychiatry traditionally have established teaching programmes in communication but the inclusion of the Department of Medicine has made a significant impact. Students have come to realize that the taking of a good history demands as much skill as the physical examination of the patient and is an important aspect of any clinical assessment.

Communication↗