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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

At least 307 records · Page 17Linked to original sources
PubMed1980

PCA: effects on ejaculation, thermoregulation, salivation, and irritability in rats.

The short term monoamine releaser p-chloroamphetamine (PCA) was injected intraperitoneally in male rats housed at 20 degrees C. Within 2 hr of PCA injections (2.5, 5.0, 8.0 or 10.0 mg/kg), rats showed ejaculation, decreased colonic temperature, increased salivation, and increased irritability. Ejaculation and salivation scores were considerably lower in the 2.5 mg/kg than in the higher dose groups, but otherwise were not dose dependent at the doses used. Hypothermia was of similar magnitude in all groups, but lasted longer in the higher dose groups. Irritability increased with dose size. In order to study the role of ambient temperature in PCA-induced behavioral changes, observations were made on an additional group or rats housed at the higher ambient temperature of 25 degrees C. In these rats an increase, rather than a decrease, in mean colonic temperature was observed following PCA injection (5 mg/kg). Ejaculation and irritability scores were similar to those observed at the lower ambient temperature, but salivation was enhanced. It is suggested that PCA induces ejaculation, salivation, irritability and, depending on the ambient temperature, either hypothermia or hyperthermia.

Aggression↗
PubMed1980

Prolymphocytic leukaemia: an ultrastructural study of 22 cases.

Twenty-two cases of prolymphocytic leukaemia (PLL) have been studied by transmission electron microscopy (TEM); 17 had B-cell surface markers (B-PLL) and five had T-cell characteristics (T-PLL). The predominant cell, the prolymphocyte, has distinct features which were common to all cases: it is a relatively large lymphoid cell with a prominent nucleolus, well condensed peripheral nuclear chromatin and a variable amount of heterochromatin in intranuclear clumps. Eight cases of PLL (seven B-PLL, one T-PLL) showed minor morphological deviations from typical PLL which may present diagnostic difficulties when studied only at light microscopy: the cells in four of these had some features in common with those of chronic lymphocytic leukaemia (CLL), namely round regular nuclei and heavy chromatin condensation, but the nucleoli were larger in the PLL cases. In four other cases nuclear clefting was a prominent feature at TEM. B-PLL can be distinguished by ultrastructural features from other B-cell malignancies, e.g. follicular lymphoma, B-CLL and B-acute lymphoblastic leukaemia.

B-Lymphocytes↗
PubMed1980

Ultrastructural cytochemistry of leukaemic cells: characterization of the early small granules of monoblasts.

An ultrastructural study of blast cells showing either monocytic or granulocytic differentiation was carried out with the acid phosphatase (AP) and myeloperoxidase (MPO) reactions. Eight cases of acute myeloid leukaemia (AML) and three of chronic granulocytic leukaemia in blast crisis were studied. A hitherto unrecognized small lysosomal granule characterized by AP activity and lack of MPO was present in the majority of cells of all six monoblastic leukaemias. These granules ranged from 0.05 to 0.2 micron in size and were distributed throughout the cytoplasm, frequently at the periphery of the cells. A small proportion of monoblasts showed AP reactivity in the Golgi cisternae. Both AP and MPO were positive in the granules of promonocytes; however, MPO positive granules were predominant in late promonocytes. Larger granules (0.2--0.6 micron) with MPO reactivity were characteristic of myeloblasts. In only two out of four cases did these granules show AP positivity, suggesting that, in contrast to monoblasts, AP activity is a late feature of myeloblastic differentiation. This study shows that ultrastructural cytochemistry may be helpful in the recognition and classification of acute leukaemias by demonstrating the early differentiation features of monocytic and granulocytic precursors.

Acid Phosphatase↗
PubMed1980

Cellular location of enzymes involved in chondroitin sulfate breakdown by Bacteroides thetaiotaomicron.

Bacteroides thetaiotaomicron, a gram-negative anaerobe found in human colons, could utilize chondroitin sulfate, a tissue mucopolysaccharide, as its sole source of carbohydrate. The enzymes responsible for the breakdown of chondroitin sulfate by B. thetaiotaomicron were similar to those produced by Proteus vulgaris and Flavobacterium heparinum and included a lyase (EC 4.2.2.4), which degraded chondroitin sulfate into sulfated disaccharides, sulfatases (EC 3.1.6.4), which removed the sulfate residues, and a glucuronidase, which broke the unsulfated disaccharides into monosaccharide components. Chondroitin sulfate lyase, the first enzyme in the breakdown sequence, was not extracellular. It appeared to be located in the periplasmic space since lyase activity was released by treatment with ethylenediaminetetraacetate and lysozyme. Moreover, sodium polyanethole sulfonate, a high-molecular-weight inhibitor of chondroitin lyase, did not inhibit breakdown of chondroitin sulfate by intact bacteria. The sulfatase and glucuronidase appeared to be intracellular. None of these enzymes was strongly bound to membranes, and none of the steps in the breakdown of chondroitin sulfate was sensitive to oxygen.

Bacteroides↗
PubMed1980

Skin abscess caused by Candida albicans: unusual presentation of C. albicans disease.

A 9-month-old patient developed a Candida albicans skin abscess at the repair site of a lumbar myelomeningocele. There was no evidence of C. albicans infection elsewhere in the body. The infection may have been acquired at the time of the original myelomeningocele repair at 2 days of age. The abscess was cured by surgical drainage and amphotericin B therapy. This case indicates that laboratories should be aware of C. albicans as an unusual cause of abscess.

Abscess↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1979

'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↗
PubMed1979

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↗
PubMed1979

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↗