PubMed Health⌕ Search

Biomedical subjects

M Walters

Publications and source records attributed to M Walters.

At least 55 records · Page 3Linked to original sources
PubMed1991

POSSUM: a scoring system for surgical audit.

POSSUM, a Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity, is described. This system has been devised from both a retrospective and prospective analysis and the present paper attempts to validate it prospectively. Logistic regression analysis yielded statistically significant equations for both mortality and morbidity (P less than 0.001). When displayed graphically zones of increasing morbidity and mortality rates could be defined which could be of value in surgical audit. The scoring system produced assessments for morbidity and mortality rates which did not significantly differ from observed rates.

Aged↗
PubMed1988

Isolation of a chemotactic protein for neutrophils from human ovarian follicular fluid.

Human follicular fluid was found to contain a factor chemotactic for human neutrophils. This chemotactic activity was shown to be heat labile and trypsin sensitive. Gel permeation chromatography experiments indicate that the chemotactic protein has an approximate molecular weight of 100 kd. Isoelectric focussing suggests an isoelectric point for this protein of around 5.8. The biologic and clinical significance of this apparently unique chemotactic protein remains to be determined.

Body Fluids↗
PubMed1987

Reduced serum tricyclic levels due to gel separators.

Sixty-three blood samples were obtained from 48 subjects taking tricyclic antidepressants. Samples were simultaneously collected in Becton-Dickinson Vacutainer tubes for measurement of serum and plasma tricyclic antidepressant concentrations. Serum was drawn into red stopper tubes (without gel separator) and into speckled stopper serum separator tubes (with gel separator), while plasma was collected in green stopper tubes (heparinized). Imipramine, desipramine, amitriptyline, and nortriptyline concentrations were all significantly lower in serum separator samples than in either plasma or red stopper serum collection tubes. Serum and plasma concentrations were similar.

Antidepressive Agents, Tricyclic↗
PubMed1985

Bronchial challenge with room temperature isocapnic hyperventilation. A comparison with histamine challenge.

We evaluated isocapnic hyperventilation with room temperature gas (IHV) as a test of bronchial hyperreactivity and compared it with histamine challenge (HC) in three groups of subjects: normal subjects, known mild asthmatic patients, and patients referred to the pulmonary clinic for a chief complaint of dyspnea. Physical examination at the time of evaluation was negative in all subjects. When the criterion for a positive reaction to IHV was a decrease in FEV1 of 10 percent or greater, and the criterion for a positive reaction to HC was a PD20 (concentration of inhaled histamine necessary to decrease FEV1 by at least 20 percent) of less than 10 mg/ml, the specificity of both tests was 100 percent. The sensitivity of both tests as evaluated from the known asthmatic patients was also 100 percent. Among the dyspneic patients, eight of 30 reacted to both IHV and HC, two of 30 reacted to HC alone, and eight of 30 reacted to IHV alone. It was concluded that IHV compares favorably with HC as a test of bronchial hyperreactivity, patients with clinical histories highly suggestive for asthma might not need to undergo bronchial challenge testing, and neither HC nor IHV when used alone is able to identify all of the hyperreactive patients.

Adolescent↗
PubMed1983

Cystosarcoma phylloides in adolescent female patients.

Nine cases of cystosarcoma phylloides in adolescent female patients are reported along with an additional 35 cases collected from the literature. Analysis of these 44 cases revealed 37 (84.1 percent) benign lesions, 6 (13.6 percent) malignant tumors, and 1 borderline lesion. Excision was the most common operative procedure and was performed in 35 patients. Nine patients underwent mastectomy. There were three recurrent lesions (one benign and two malignant) for a recurrence rate of 6.8 percent. Wide excision was successful in the treatment of recurrent lesions. On the basis of these data, excision is the preferred initial therapy of cystosarcoma phylloides in the adolescent patient regardless of the histologic classification of the lesion. Malignant cystosarcoma is more likely to recur than a benign lesion but a recurrence can be managed with reexcision. Sacrifice of the adolescent breast at the initial procedure is strongly discouraged.

Adolescent↗
PubMed1982

The mesothelium: its fibrinolytic properties.

We have investigated the fibrinolytic properties of the mesothelium by developing a test system in which standard tissue samples can be assessed in a comparative and semi-quantitative manner. The problem whether plasminogen activators were generated by the mesothelium itself or were transported from a subserosal site was also studied. A standard system was developed by using a uniform gelatin disc to obtain a monolayer imprint of mesothelium and subsequently incorporating several of these samples on a fibrin plate. Pure cultures of mesothelial cells were able to induce fibrinolysis.

Animals↗
PubMed1981

Phosphorylation of the calcium ion-regulated thin filaments from vascular smooth muscle. A new regulatory mechanism?

The thin filaments of vascular smooth muscle (pig aorta) contain a Ca2+-sensitive regulatory system that resembles troponin-tropomyosin [Marston, Trevett & Walters (1980) Biochem. J. 185, 355-365]. Our thin-filament preparations also contain enzymes that phosphorylate and dephosphorylate a specific protein. Initial rate of phosphorylation was 0.42 +/- 0.10 (95% confidence limits) mumol of Pi/min per g of thin filaments; half-maximal incorporation was obtained in 4 1/2 min, and a maximum of 1.8 +/- 0.1 mumol of Pi/g of thin filaments was incorporated after 40 min (conditions: 1 mM-MgATP, 60 mM-MgATP, 60 mM-KCl, 10 mM-imidazole, pH 7.0, 5 mM-MgCl2, 10 mM-NaN3, 0.5 mM-dithiothreitol, 0.1 mM-CaCl2, 25 degrees C). On gel electrophoresis in polyacrylamide (4-30% gradient)/0.25% sodium dodecyl sulphate gel over 75% of protein-bound phosphate was in a single protein of mol.wt. 21000. On electrophoresis in polyacrylamide (8%)/6 M-urea (pH 8.6) gel the phosphoprotein remained at the origin. Phosphorylation was associated with an increase in the concentration of high-affinity (K congruent to 10(6) M-1) Ca2+-binding sites from 0.8-1.5 to 6.3 mumol of Ca2+/g of thin filaments. Phosphorylation also changed the regulatory properties of the skeletal-muscle myosin-aorta thin-filament MgATPase; maximum activity was unaltered, but the phosphorylated thin filaments required only 0.36 microM-Ca2+ for half-activation compared with 2.7 microM-Ca2+ for unphosphorylated thin filaments. The possible regulatory role of thin-filament phosphorylation is discussed.

Actomyosin↗
PubMed1980

Calcium ion-regulated thin filaments from vascular smooth muscle.

Myosin and actin competition tests indicated the presence of both thin-filament and myosin-linked Ca2+-regulatory systems in pig aorta and turkey gizzard smooth-muscle actomyosin. A thin-filament preparation was obtained from pig aortas. The thin filaments had no significant ATPase activity [1.1 +/- 2.6 nmol/mg per min (mean +/- S.D.)], but they activated skeletal-muscle myosin ATPase up to 25-fold [500 nmol/mg of myosin per min (mean +/- S.D.)] in the presence of 10(-4) M free Ca2+. At 10(-8) M-Ca2+ the thin filaments activated myosin ATPase activity only one-third as much. Thin-filament activation of myosin ATPase activity increased markedly in the range 10(-6)-10(-5) M-Ca2+ and was half maximal at 2.7 x 10(-6) M (pCa2+ 5.6). The skeletal myosin-aorta-thin-filament mixture gave a biphasic ATPase-rate-versus-ATP-concentration curve at 10(-8) M-Ca2+ similar to the curve obtained with skeletal-muscle thin filaments. Thin filaments bound up to 9.5 mumol of Ca2+/g in the presence of MgATP2-. In the range 0.06-27 microM-Ca2+ binding was hyperbolic with an estimated binding constant of (0.56 +/- 0.07) x 10(6) M-1 (mean +/- S.D.) and maximum binding of 8.0 +/- 0.8 mumol/g (mean +/- S.D.). Significantly less Ca2+ bound in the absence of ATP. The thin filaments contained actin, tropomyosin and several other unidentified proteins. 6 M-Urea/polyacrylamide-gel electrophoresis at pH 8.3 showed proteins that behaved like troponin I and troponin C. This was confirmed by forming interspecific complexes between radioactive skeletal-muscle troponin I and troponin C and the aorta thin-filament proteins. The thin filaments contained at least 1.4 mumol of a troponin C-like protein/g and at least 1.1 mumol of a troponin I-like protein/g.

Actins↗
PubMed1979

Postnatal support.

Explore the source record for details and available documents.

Child Health Services↗
PubMed1976

Characterization of an adenylate cyclase system sensitive to histamine H2-receptor excitation in cells from dog gastric mucosa.

A method of preparing viable cells from dog gastric mucosa is described. Cyclic AMP in these cells is elevated by histamine and 4-methyl histamine but 2-methyl histamine is only a weak agonist. The effects on cyclic AMP levels are inhibited competitively by metiamide and burimamide which give apparent KBvalues of 3.5x10-7 M and 2.3x10-6 M, respectively. These values are similar to those reported for other histamine H2-receptor systems. The H1-receptor antagonists, mepyramine and chlorpheniramine, have no inhibitory effect on the histamine induced elevation of cyclic AMP: promethazine inhibits the system but not by a competitive mechanism. It is concluded that the histamine stimulated adenylate cyclase system is probably located in the parietal cell component.

Adenylyl Cyclase Inhibitors↗
PubMed1973

Comex 1972.

Explore the source record for details and available documents.

Asia↗