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Biomedical subjects

B A Martin

Publications and source records attributed to B A Martin.

At least 73 records · Page 4Linked to original sources
PubMed1987

Regional differences in neutrophil margination in dog lungs.

We investigated the relationship between polymorphonuclear leukocyte (PMN) retention and erythrocyte (RBC) velocity in the lungs of mongrel dogs. Regional velocity was estimated by measuring regional RBC transit times and was correlated with the retention of PMN found in the same lung sample 10 min after the injection of a bolus of labeled cells. Data from the whole lung showed that the total number of cells marginated in the pulmonary vasculature was 2.4 times as great as the number present in the circulation and that this pool turned over at a rate of 1%/s. The regional data showed increased retention, indicating slower PMN turnover in the upper lung regions, which have longer transit times and therefore slower blood velocities than the RBC is attributed to a greater discrepancy between PMN and RBC is attributed to a greater discrepancy between PMN and capillary size and the fact that PMN are less deformable than RBC. The large number of capillary segments present in the lung allows neutrophils to move more slowly while RBC stream around them. We conclude that there are approximately 2.5 times as many PMNs marginated in the lung as there are in the total circulating blood volume of the dog and that the pulmonary marginated pool turns over at approximately 1%/s with slower turnover in the upper compared with the lower regions of the lung.

Animals↗
PubMed1987

Marginated pool of neutrophils in rabbit lungs.

The size and location of the marginated pool of neutrophils (PMNs) in rabbit lungs were evaluated, and the rate of exchange of the PMNs with the circulating pool was determined. 99mTc-labeled erythrocytes (99mTc-RBCs) and 125I-labeled macroaggregated albumin (125I-MAA) were used to determine RBC transit times in the pulmonary circulation. Radiolabeled PMNs were studied on their first passage through the lungs. After 10 min of circulation, the lungs were fixed, gamma counted, and prepared for morphometric and autoradiographic studies; 74 +/- 3% of the PMNs was retained in the lungs on the first passage, and 23 +/- 2% was within the pulmonary marginated pool 10 min later. The regional PMN retention and the rate of exchange between the marginated and circulating PMN pools in the lung were directly related to RBC transit time. The radiolabeled PMNs distributed similarly to the unlabeled cells within the microvasculature and had a similar exchange rate between the marginated and circulating pools (1.4 +/- 0.2%/s using labeled cells and 1.5 +/- 0.5%/s using unlabeled cells). The marginated pool was located primarily within alveolar capillaries and contained two to three times as many PMNs as the total circulating pool.

Animals↗
PubMed1987

Civil commitment and consent for electroconvulsive therapy in Ontario.

Among the most contentious legal and ethical issues concerning the use of electroconvulsive therapy (ECT) are the criteria for obtaining a valid consent to treatment and its administration to involuntarily hospitalized patients, with or without consent. This paper reviews the consent process, in particular the assessment of competence, as it is affected by the symptoms and clinical circumstances, including civil status, of those patients for whom ECT is prescribed. The ECT caseload at one psychiatric facility was reviewed to determine the diagnosis and civil status of each patient and the source of consent for each course of ECT prescribed over a 10-year period. Significant differences were found in the diagnostic distribution and the source of consent by diagnostic group between the 1,042 courses administered to informal patients and the 249 courses to involuntary patients. The results are discussed in the context of relevant Ontario legislation and hospital policies. Recommendations are made for the improvement of procedural safeguards to protect the autonomy of all patients.

Commitment of Persons with Psychiatric Disorders↗
PubMed1986

A Comparison of Oleic Acid Metabolism in the Soybean (Glycine max [L.] Merr.) Genotypes Williams and A5, a Mutant with Decreased Linoleic Acid in the Seed.

The metabolism of oleoyl coenzyme A (CoA) was examined in developing seed from two soybean (Glycine max [L.] Merr.) genotypes: Williams, a standard cultivar and A5, a mutant containing nearly twice the oleic acid (18:1) content of Williams. The in vitro rates of esterification of oleoyl-CoA to lysophosphatides by acyl-CoA: lysophosphatidylcholine acyltransferase was similar in both genotypes and lysophosphatidyl-ethanolamine was a poor substrate. Crude extracts desaturated exogenous [1-(14)C]dioleoyl phosphatidylcholine at 14% of the rate achieved with [1-(14)C]oleoyl-CoA, and 50 micromolar lysophosphatidylcholine. The desaturase enzyme also required NADH for full activity. Extracts from Williams contained 1.5-fold more oleoyl phosphatidylcholine desaturase activity, on a fresh weight basis, than did A5 and appeared to have a similar affinity for oleoyl-CoA. There was 1.2- to 1.9-fold more linoleic acid (18:2) in phosphatidylcholine from Williams than from A5, measured at two stages of development, but both genotypes had a similar distribution of fatty acids in the one and two positions. Phosphatidylethanolamine in A5 contained relatively more linoleic acid (18:2) in the one position than did Williams. The increased oleic acid (18:1) content in A5 appeared to be a result of decreased rates of 18:1 desaturation of oleoyl-phosphatidylcholine in this genotype.

Journal Article↗
PubMed1986

Changes in Soybean (Glycine max [L.] Merr.) Glycerolipids in Response to Water Stress.

Soybean (Glycine max [L.] Merr.) plants with the first trifoliate leaf fully expanded were exposed to 4 and 8 days of water stress. Leaf water potentials dropped from -0.6 megapascal to -1.7 megapascals after 4 days of stress; then to -3.1 megapascals after 8 days without water. All of the plants recovered when rewatered. The effects of short-term drought stress on triacylglycerol, diacylglycerol, phospholipid, and galactolipid metabolism in the first trifoliate leaves was determined. Leaf triacylglycerol and diacylglycerol content increased 2-fold during the first 4 days of stress and returned to control levels 3 days after rewatering. The polar lipid fraction, which contained phospholipids and galactolipids, changed little during this time. The linolenic acid (18:3) content of the triacylglycerol and diacylglycerol increased 25% during stress and the polar lipid 18:3 content decreased 15%. The pattern of glycerolipid labeling, after applying [2-(14)C]acetate to intact leaves was altered by water stress. After 4 days of water stress the radioactivity of phosphatidic acid + phosphatidylinositol, phosphatidylcholine, triacylglycerol, and diacylglycerol increased between 4 and 9% (compared to control plans) while radioactivity of phosphatidylethanolamine, monogalactosyldiglyceride, and digalactosyldiglyceride decreased 2 to 11%. These data indicated that increased levels of triacylglycerol and diacylglycerol observed during water stress were attributed to de novo synthesis rather than breakdown or reutilization of existing glycerolipids and fatty acids.

Journal Article↗
PubMed1986

Electroconvulsive therapy and brain damage: the Ontario Supreme Court hearing of the evidence.

The issue of whether electroconvulsive therapy (ECT) causes brain damage was examined by the Supreme Court of Ontario when an involuntarily hospitalized patient attempted to overturn a treatment order for ECT made by a review board. The Ontario Mental Health Act (MHA) specifically prohibits the authorization of psychosurgery by a review board. In this case, the patient argued that the board had exceeded its jurisdiction in authorizing ECT because ECT fell within the definition of psychosurgery in the Ontario MHA. This paper reviews the legal issues involved and summarizes the most substantive evidence presented for and against any causal association between ECT and demonstrable brain damage. The judicial decision upholding the treatment order is discussed.

Brain Damage, Chronic↗
PubMed1986

Electroconvulsive therapy: contemporary standards of practice.

Electroconvulsive therapy (ECT) has retained an important but controversial position in contemporary psychiatric therapeutics. Out-dated standards of clinical practice regarding its technical administration, clinical indications, and dosage continue to influence the present use of ECT. Insofar as present knowledge permits, this paper describes optimum clinical standards for the use of ECT in contemporary practice. Where knowledge is insufficient to permit articulation of absolute standards, guidelines for its clinical use are presented. Particular emphasis is placed upon a narrow definition of the clinical indications for ECT, clearly linked to its demonstrated effectiveness and potential benefit in excess of its risks to any given patient. The technical administration of the procedure is described in detail with particular emphasis on the pre-treatment protocol, including consent, and the treatment dosage, including stimulus waveform, electrode placement, and number of treatments per course. The major deficiencies in knowledge are identified.

Amnesia↗
PubMed1986

The effect of angiotensin II on glomerular function and morphology in the rat.

We have observed alterations of glomerular and afferent arteriolar structure in nephrotoxic and ischemic models of acute renal failure. These alterations may have been caused by angiotensin II. To test this notion, we infused the peptide directly into the left renal artery of anesthetized rats. At sub-pressor doses of 1.9 and 6.5 ng/100g body weight/min, the peptide caused dose-related decreases in glomerular filtration rate similar to those that occur in models of acute renal failure. In some animals, methacrylate casts of the infused and contralateral kidneys were made for later examination by scanning electron microscopy. In other animals, the kidneys were fixed with glutaraldehyde for examination of the glomerular epithelium and endothelium by scanning electron microscopy. Cast analysis showed no detectable alteration of afferent arteriolar diameter, and only moderate bilateral changes in the tapering of the arterioles. In contrast, the diameter of the casted glomerular tuft was significantly reduced by the highest dose of angiotensin II. No alterations of the glomerular epithelium or endothelial fenestrae were observed. We conclude that angiotensin II probably did not mediate the changes in glomerular structure in our earlier studies of acute renal failure, even though similar reductions of glomerular filtration rate occurred. Reduced diameter of the glomerular tuft is consistent with a possible role for angiotensin II as a modulator of intrinsic contractile elements in glomeruli.

Acute Kidney Injury↗
PubMed1985

Regional differences in erythrocyte transit in normal lungs.

We measured regional blood volume and flow in the lungs of nine mongrel dogs. The time taken for the erythrocytes to transit through individual lung regions was calculated from the relationship t = V/Q, where V is blood volume and Q is flow. The data show that the total pulmonary blood volume was 82 +/- 6 ml and that the average time spent in the pulmonary vascular bed was 2.86 +/- 0.31 s. The frequency distribution of the transit times ranged from 0.41 to 6 s in the experiment with the shortest mean transit (1.62 s) and from 0.9 to greater than 20 s in the experiment with the longest mean transit time (4.6 s). The regional data show that the longer transit times were in the upper lung and that expansion of the blood volume as flow increased down the lung prevented an excessive shortening of the transit time. We conclude that increasing regional blood flow is associated with an expansion of regional blood volumes so that the transit times remain relatively constant.

Animals↗
PubMed1985

Civil commitment trends in Ontario: the effect of legislation on clinical practice.

The rationale for and history of civil commitment legislation in Ontario are reviewed. The civil commitment rate in Ontario from 1926 to 1980 for provincial psychiatric hospitals, and from 1974 to 1980 for all psychiatric inpatient facilities was analyzed to detect variation in the rate over time and with relevant legislation. The findings indicate that mental health legislation has had little effect on commitment practices in Ontario. In addition, the variation in the commitment rate over the period reviewed cannot be ascribed to inconsistent application by physicians. The other variables affecting the rate are discussed in this context. The need for more descriptive studies of the major determinants of the commitment rate is emphasized.

Commitment of Persons with Psychiatric Disorders↗
PubMed1985

The effect of body temperature on leukocyte kinetics during cardiopulmonary bypass.

Leukocyte kinetics were investigated in 22 patients undergoing cardiopulmonary bypass to determine the nature of the changes in the white blood cell count associated with this procedure. Both polymorphonuclear leukocytes and lymphocytes were taken up by the lung as pulmonary blood flow was lowered, but only polymorphonuclear leukocytes were taken up as blood flow was restored. The complement 3a level was increased approximately twice the control value within 2 minutes of going on bypass and remained elevated throughout the procedure. The peripheral white blood cell count doubled during the bypass procedure owing to a release of polymorphonuclear leukocytes and their precursors from the bone marrow. The increase in polymorphonuclear leukocytes was prevented by hyperthermia but reappeared quickly when the body temperature was restored to 36 degrees to 37 degrees C.

Adult↗
PubMed1984

Induction of proteins in human lymphoblastoid cells by recombinant alpha interferon.

Two-dimensional gel electrophoresis, using either silver staining or pulse labeling with 35S-L-methionine and autoradiography, was employed to determine changes in the synthesis of proteins that may be involved in the antiproliferative effects of recombinant alpha interferon (IFNrA) on Burkitt's lymphoma Daudi cells. IFNrA initiated and/or augmented the synthesis of at least 13 proteins that were distinct in molecular weights and isoelectric properties. Synthesis of several of these IFN-enhanced proteins was inhibited by actinomycin-D, an inhibitor of mRNA synthesis. Although IFN-induced antiproliferative effects were observed at 48 h, an increase in the synthesis of several proteins was observed as early as 3 h. The levels of these IFN-enhanced proteins in treated cells continued to increase through 24 h. At least two proteins of approximately 17 kD were observed to be synthesized in IFN-treated cells but not in control cells. Neither inhibition of synthesis of any particular protein nor post-synthetic modification of proteins in response to IFNrA was observed with these methods. The results of this study are compared and contrasted to those of several other laboratories.

Burkitt Lymphoma↗
PubMed1984

Effect of pulmonary blood flow on leukocyte uptake and release by dog lung.

The effect of pulmonary blood flow on leukocyte uptake and release by the lung was examined in 10 anesthetized spontaneously breathing dogs. Pulmonary arterial and pulmonary venous blood was sampled with catheters placed into the right ventricle and aorta, respectively. Pulmonary blood flow was lowered by inflating a balloon catheter located in the inferior vena cava. In five experiments simultaneous blood samples were drawn from the right ventricle and aorta at 10-s intervals during a control period, a 2- to 3-min period of low flow, and a recovery period. In five additional experiments, less frequent samples were taken over periods of 15-60 min. Total leukocyte concentrations and differential counts were determined for each blood sample. The study shows that large numbers of leukocytes become sequestered within the lung when pulmonary blood flow is low and that an equivalent number of cells are released from the lung after deflation of the balloon catheter. Both the polymorphonuclear leukocytes and the lymphocytes were taken up by the lung when pulmonary blood flow was reduced. We conclude that pulmonary blood flow has a marked effect on the uptake and release of leukocytes by the dog lung.

Animals↗
PubMed1984

Leukocyte kinetics in the human lung: role of exercise and catecholamines.

In six normal supine subjects epinephrine infusion produced a greater leukocytosis with smaller changes in heart rate and blood pressure than did norepinephrine or isoproterenol. Upright exercise in those subjects produced a greater leukocytosis than supine exercise at the same work load. To determine the lung's participation in these events, indium-labeled neutrophils (PMN) were given to four of the subjects. We found that 20-25% were retained in the first pass through the lung when compared with technetium-labeled erythrocytes. The number of labeled PMN in the lung gradually decreased and the number in the spleen and the liver increased. Exercise and catecholamine infusion caused an acceleration in the release of labeled cells from the lung, an increase in both labeled and unlabeled cells in the peripheral blood, and an increase in the number of labeled cells in the liver and spleen. This suggests that increased perfusion of low-flow areas in the lung may contribute to the increased leukocytosis seen in association with both exercise and catecholamine infusion.

Blood Pressure↗
PubMed1984

The Clarke Institute experience with electroconvulsive therapy: I. Development of a clinical audit procedure.

Over the past forty-five years, there has been a progressive refinement of the standards of practice of electroconvulsive therapy (ECT). The need to review contemporary practice patterns to maintain and further improve those standards is discussed. In this context, the respective roles of medical audits and surveys of practice are described and the methodology of recent surveys critically examined. A procedure for the collection of reliable and complete data on the more than 22,000 treatments administered at one psychiatric hospital is described as the essential element of both an accurate survey of practice and a clinical audit. The audit is designed to retrospectively review and prospectively monitor the practice of ECT to identify the areas of conformity with and divergence from current standards of practice. it is recommended that this kind of audit procedure be an integral part of the present day administration of ECT. It is also suggested as a paradigm for hospital practice auditing with potential application to other specific treatments.

Data Collection↗