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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

At least 37 records · Page 2Linked to original sources

Phase II study of combination 4'-epidoxorubicin and mitomycin C in recurrent epithelial ovarian cancer.

Thirty-three evaluable patients who had epithelial ovarian cancer that had not responded to treatment were entered into a phase II study of combination epirubicin and mitomycin C. Epirubicin (65 mg/m2) and mitomycin C (4 mg/m2) were administered separately, each as an i.v. bolus every 4 weeks. Ten patients (30%) had a complete or partial responses. The median duration of response was 20 weeks (range, 9-53). The regimen was well tolerated. Myelotoxicity occurred in four patients requiring hospitalization for septicaemia. Eleven patients had a blood transfusion. Alopecia was common, and nausea and vomiting, though frequent, usually mild. Cardiological toxicity was observed in one patient only. She developed congestive cardiac failure after an acute myocardial infarction. This regimen is active in advanced ovarian cancer that has not responded to prior treatment and warrants further study combination with other active drugs as a first-line regimen for ovarian cancer.

Adult

The contribution of the three columns of the spine to spinal stability: a biomechanical model.

UNLABELLED: The load carrying capacity (LCC) of the human spine was evaluated in 10 human cadaver spines. The specimens consisted of segments from T11 to S1 with markers placed on the specimens at each vertebral level in both Ap and lateral planes. The specimens were loaded to 1250 N and spinal deflections were recorded and photographed at 125 N intervals during the loading cycle. In 5 specimens, axial and flexion loads were applied to the intact spine. The anterior and middle columns were destroyed in sequence at L2 and the loading process repeated. In the remaining 5 specimens, axial and extension loads were applied with the spine intact and after the posterior and middle columns were destroyed in sequence at L2. Load deflection curves were generated for each test and comparisons were made between intact spines and spines with single and double column destruction. RESULTS: When the axis of loading was anterior to the posterior longitudinal ligament (PLL), destruction of the anterior and middle columns reduced the LCC by 46% and 68% respectively and destruction of the posterior and middle columns reduced the LCC by 30% and 63% respectively. There was minimal change in the LCC when the axis of loading was posterior to the PLL and the anterior and middle columns were destroyed. Two column destruction of the spine reduced its load carrying capacity for flexion loads by 70%. In thoracolumbar spinal fractures where flexion loads are predominant and anticipated, the authors conclude that surgical stabilisation is indicated with double column failure.

Humans

Glomus tumours: an immunohistochemical profile of 11 cases.

We studied 11 glomus tumours immunohistochemically, with a panel of connective tissue and epithelial markers. Most tumours contained small nerve fibres located in connective tissue septae between groups of glomus cells, thus accounting for the frequent occurrence of pain associated with glomus tumours. All tumours stained positively for muscle-specific actin and vimentin. Immunostaining for high and low molecular weight cytokeratins, desmin, myoglobin, S-100 protein, neurofilaments and Factor VIII related antigen was negative. Our findings confirm and amplify the proposed smooth muscle histogenesis of glomus tumours. This immunohistochemical profile may be of diagnostic value in the differential diagnosis of atypical glomus tumours.

Adolescent

Social interactions and play patterns of parents and toddlers with feminine, masculine, and neutral toys.

Children as young as 18 months display sex-stereotyped toy choices. The present study was designed to determine whether parents encourage involvement with sex-stereotyped toys or avoidance of cross-sex-stereotyped toys and to determine whether masculine and feminine toys lead to different patterns of parent-child interaction, regardless of gender. 40 parent-toddler dyads were videotaped while playing with 6 different sets of sex-stereotyped toys. Equal numbers of boys and girls were observed with mothers and fathers. The children showed greater involvement when playing with same-sex-typed toys than with cross-sex toys even when statistically controlling for parents' behaviors. Parents' verbal behaviors, involvement, and proximity to the child differed across toy groups, regardless of the parent's or child's gender. Parents' initial nonverbal responses to the toys, however, were more positive when the toys were stereotyped for the child's and parent's gender than when they were not.

Female

Intraperitoneal Vancoled does not cause chemical peritonitis.

A prior report has suggested that loading doses of intraperitoneal Vancoled (vancomycin, Lederle) cause chemical peritonitis in patients with catheter infections. The present open-label study was conducted to determine the effects of a 30 mg/kg intraperitoneal loading dose of Vancoled given to five patients with a culture-positive, erythematous, draining exit-site infection. Prior to dosing, all dialysate was drained and sent for baseline cell count and culture. The loading dose was added to the dialysate and infused in the usual fashion. A sample of dialysate was drained at two hours and sent for cell count and culture. The entire exchange was drained at four hours and also sent for cell count and culture. Serum vancomycin concentrations wer measured at four hours. Baseline dialysate contained less than 9 white blood cells per microliter in all patients. Two and four hour samples contained less than 4 and less than 11 white blood cells per microliter, respectively. All fluid was sterile. WB C differential counts were unremarkable. No adverse effects occurred. The mean serum vancomycin concentration was 26.5 micrograms/ml. Intraperitoneal Vancoled did not cause chemical peritonitis and was well-tolerated by patients with exit-site infections.

Adult

Breech delivery: evaluation of the method of delivery on perinatal results and maternal morbidity.

A retrospective study of 460 single-gestation infants in breech position was conducted at the University of Colorado Medical Center to assess the impact of a policy for the selection of cases for vaginal delivery. Among infants weighing more than 2,500 grams, there was an increase in the cesarean section rate from 13% to 54%, with an associated increase in maternal morbidity from 7% to 15%. This occurred with no significant reduction in adverse perinatal outcome. However, a case-by-case review suggests that more frequent and timely cesarean sections would have further reduced perinatal morbidity and deaths among term infants. Among the infants weighing 2,500 grams or less there was an increase in cesarean births from 5% to 55% following the introduction of the strict criteria for vaginal delivery. Among the infants weighing 1,501 to 2,500 grams there was no significant difference in survival between the cesarean and vaginally delivered patients. Although infants weighing 501 to 1,500 grams delivered by cesarean section survived more frequently than did those delivered vaginally, the differences in perinatal deaths may have been due to a higher birth weight in the cesarean-delivered infants or an over-all improvement in neonatal intensive care for infants of very low birth weight.

Apgar Score

Direct tissue isoelectric focusing in agarose.

We are isoelectric focusing small amounts of tissues placed directly on electroendosmosis-free agarose gels instead of using the saline extracts of tissue homogenates. More numerous proteins are extracted during isoelectric focusing of the solid tissues than present in the same tissues.

Adenocarcinoma

'Prolymphocytoid' transformation of chronic lymphocytic leukaemia.

We report clinical, morphological and surface marker studies on seven patients with the common type of chronic lymphocytic leukaemia (CLL) whose disease underwent an insidious though progressive change in character with increasing refractoriness to treatment. This transformation was accompanied by the appearance of a population of immature-appearing cells in the peripheral blood which resembled prolymphocytes, both at light and electron microscopy. The characteristic morphological feature was the presence of two distinct populations of cells, the typical CLL lymphocytes and the 'prolymphocytoid' cells. These cells retained the surface characteristics of CLL, i.e. the information of mouse RBC rosettes and sparse surface-bound immunoglobulin. This transformation can be distinguished by morphological and surface marker criteria from acute leukaemia occurring in CCL, Richter's syndrome and prolymphocytic leukaemia. The recognition of this group of CLL patients may add a new prognostic index to CLL and may help plan subsequent trials for the treatment of the disease.

Aged

A pilot study on left ventricular dimensions and wall stress before and after submaximal exercise.

Left ventricle dimensions and wall stress were measured echocardiographically before and immediately after exercise in 14 athletes and 7 control subjects. Our findings suggest that afterload is an important determinant of cardiac performance and wall hypertrophy in athletes. In spite of major changes in heart rate and blood pressure, left ventricular wall stress remains unchanged following submaximal exercise, in trained and untrained hearts. It would appear that the changes in heart size during exercise are to a large extent limited in untrained ventricles, as smaller left ventricular dimensions are required, to "normalise" wall stress. This results in a lower stroke volume for a given stroke dimensional change. Consequently cardiac output is a function of heart rate rather than stroke volume in untrained subjects. The effect of increased muscle mass in athletes, is to permit larger left ventricular dimensions for a given afterload, thus stroke volume can be augmented. The increase h/R ratio suggests that afterload is more important than preload in the development of left ventricular hypertrophy in rowers and swimmers.

Adolescent

Management of ventricular shunt infections.

The authors report the incidence (2.7%) of shunt infection in a series of 778 consecutive shunt procedures. The management of these infections and an additional group of infected patients operated elsewhere is discussed. A protocol is given for the treatment of external infections, gram-positive internal infections and gram-negative internal infections.

Anti-Bacterial Agents

Ultrastructural, cytochemical and surface marker analysis of cells during blast crisis of chronic granulocytic leukaemia.

The blast cells of 19 patients with Ph1-positive chronic granulocytic leukaemia (CGL) in blast crisis (BC) were studied by means of several techniques: morphology, cytochemistry, ultrastructure, surface markers and the enzyme terminal transferase. Cells of BC were, in most case, extremely undifferentiated by morphology and cytochemistry. Our data showed that in 80% of cases the cells in BC were myeloid and in 20% they were "lymphoblastic". The M1, M2 and M3 forms (FAB classification) were rare in CGL BC compared with acute myeloid leukaemia (AML). A megakaryoblastic type was seen in 15% of BC cases; the existence of this form could only be demonstrated by electron microscopy. The limphoblastic BC cells were, as in acute lymphoblastic leukaemia (ALL), positive with Greaves' anti-ALL serum and had elevated levels of terminal transferase. A case of a 17-year old boy presenting as ALL, reverting to chronic-phase CGL after complete remission and developing terminally a myeloid BC is described in detail. This case helps to illustrate a new form of natural history of CGL unveiled by the present study.

Adolescent