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Biomedical subjects

D V Wilson

Publications and source records attributed to D V Wilson.

At least 37 records · Page 2Linked to original sources

Pharmacologic treatment of priapism in two horses.

Benztropine mesylate was used successfully to treat priapism that developed during anesthesia in 2 horses. After IV injection, there was a rapid resolution of signs in both horses, and no side effects were observed. The choice of an effective method to treat priapism is challenging because precise causes in most patients have not been well-defined. Benztropine mesylate is a synthetic compound resulting from the combination of the active portions of atropine and diphenhydramine, and is believed effective because of its central acetyl-choline-antagonizing properties.

Anesthesia, General↗

Positive end-expiratory pressure during colic surgery in horses: 74 cases (1986-1988).

Positive end-expiratory pressure (PEEP) was applied in 74 anesthetized, ventilated horses during colic surgery, to attempt to increase arterial oxygen tensions. In 28 horses with an initial PaO2 less than 70 mm of Hg, PEEP increased PaO2 values to a mean of 173 +/- 24 mm of Hg. Arterial oxygen content increased from 14.1 +/- 0.05 ml/dl to 17.2 +/- 0.05 ml/dl. In the remaining 46 horses, PEEP increased PaO2 from a mean value of 101 +/- 6 mm of Hg to 194 +/- 15 mm of Hg, and arterial oxygen content increased from 14.9 +/- 0.09 ml/dl to 16.9 +/- 0.07 ml/dl. Cardiovascular depression and decrease in arterial blood pressure was observed after the application of PEEP in 54 horses. These 54 horses required use of pressors (n = 8), inotropes (n = 32), or both (n = 14) to keep the mean arterial blood pressure greater than 60 mm of Hg. Combined with pharmacologic support of blood pressure, PEEP could be a useful clinical treatment of arterial hypoxemia in horses.

Animals↗

Cardiopulmonary effects of positive end-expiratory pressure in anesthetized, mechanically ventilated ponies.

To investigate the cardiopulmonary effects of positive end-expiratory pressure (PEEP), values of 10, 20, and 30 cm of H2O, were applied to anesthetized, dorsally recumbent, ventilated ponies. After IV induction of general anesthesia, PEEP was superimposed on controlled ventilation with 100% oxygen, and changes in gas exchange and cardiac function were measured. Increasing values of PEEP in these ponies caused a linear increase in the mean (+/- SEM) functional residual capacity, from a control value (zero end-expiratory pressure) of 1.7 +/- 0.24 L to 2.2 +/- 0.31, 2.9 +/- 0.32 and 3.4 +/- 0.3 L at PEEP of 10, 20, and 30 cm of H2O, respectively (P less than 0.05). Paralleling these changes, intrapulmonary shunt fraction decreased significantly (P less than 0.05) from a control value of 12.9 +/- 0.5%, to 7.5 +/- 1.1 and 2.1 +/- 0.6%, at PEEP of 20 and 30 cm of H2O, respectively. Cardiac output was decreased by increasing values of PEEP, from control value of 11.7 +/- 1.56 L/min to 9.9 +/- 1.51, 8.8 +/- 1.33 and 5.62 +/- 0.56 L/min at PEEP of 10, 20, and 30 cm of H2O, respectively. Related to decreasing cardiac output, tissue oxygen delivery also decreased as PEEP was increased, from control value of 2.0 +/- 0.09 L/min to 1.8 +/- 0.07, 1.6 +/- 0.06, and 1.03 +/- 0.04 L/min at PEEP of 10, 20, and 30 cm of H2O, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗

Effects of frequency and airway pressure on gas exchange during interrupted high-frequency, positive-pressure ventilation in ponies.

Cardiovascular effects and pulmonary gas exchange were compared during conventional mechanical ventilation (CMV) and interrupted high-frequency, positive-pressure ventilation (IHFPPV) in 6 anesthetized ponies in dorsal recumbency. When the peak airway pressure (Paw) was held constant at control values attained during CMV (18 to 20 cm of H2O), and the ventilator frequency of IHFPPV was varied over the range, 2.5 to 12.5 Hz, significant (P less than 0.05) changes from control values were observed only in the ratio of dead-space volume to tidal volume (VD/VT) and in the respiratory minute volume (VE). The mean (+/- SEM) carbon dioxide excretion (VCO2) was 2.12 +/- 0.1 ml/kg/min during IHFPPV. Dead-space ventilation ranged from 40 to 73.7% of total ventilation and increased directly with increasing frequency. The VE also increased, from 89 ml/kg/min at a ventilatory frequency of 2.5 Hz to 145 ml/kg/min at a frequency of 12.5 Hz. Maintaining the frequency of IHFPPV constant at 12.5 Hz and increasing the Paw over the range of 5 to 30 cm of H2O caused significant (P less than 0.05) changes in arterial partial pressure of O2 (PaO2), VCO2, pulmonary shunt fraction (QS/QT), VE, arterial-alveolar differences in oxygen tension (AaDO2), VD/VT, and cardiac output, compared with CMV. The PaO2 and the VCO2 increased linearly with increasing Paw. With increasing Paw, VD/VT decreased directly with increasing Paw from 98 to 69.3%. Gas exchange at a Paw of 15 cm of H2O during IHFPPV was equivalent to conditions at Paw of 20 cm of H2O during CMV. At a higher Paw during IHFPPV, improvements over control values were observed in gas exchange.

Airway Resistance↗

Pulmonary haemorrhage in standardbred horses after racing.

Endoscopic examinations of the upper respiratory tract were done on 92 of 314 Standardbred horses that raced one or more times at 4 consecutive, weekly race meetings. Although participation was voluntary, the characteristics of the population of horses examined were not statistically different from those of all horses that raced. No horse showed epistaxis, but 34 (32.4%) examinations of the trachea revealed blood that ranged from a trace in the tracheal mucus to large amounts scattered over the tracheal walls. Forty-four horses exhibited minor degrees of pharyngeal lymphoid hyperplasia, 2 had asynchronous movement of the left arytenoid cartilage and 15 had grains of sand in the respiratory tract. There was no association between bleeding and age, sex, distance of race, place in race or date of race. Mucus and mucopurulent material occurred less often after longer races and more often on the last 3 race nights.

Age Factors↗

Detection of gonococcal antigens in urine by radioimmunoassay.

A method of detecting gonococcal antigens by solid-phase radioimmunoassay with radioactively labelled antibody is described. A specificity test has been developed that enables this method to be used to detect gonococcal antigens in urine sediments. When sediments from samples of urine from male patients with gonorrhoea were tested, 31 (74%) of 42 gave positive results, clearly distinguishing them from sediments from urine samples from men with non-specific urethritis, none of which was positive. Ten of 14 urine sediments from urine samples from women with gonorrhoea gave positive results, as did 3 of 18 sediments from urine samples from women patients without gonorrhoea. These experiments demonstrate that gonococcal antigens can be detected in urine by radioimmunoassay; the method could be useful in diagnosis if, after refinement, its sensitivity and specificity were to be increased.

Antibody Specificity↗

A solid phase assay with radioactively-labelled antibody for the detection of Brucella abortus.

An assay for the detection of Brucella abortus is described. IgG from rabbit antisera against live brucellae or brucella extracts was chemically linked to cellulose to form a solid phase reagent capable of binding brucella antigens present in buffer solutions or serum. After washing away any unbound material the presence of bound antigen was revealed by incubation with radioactively-labelled anti-brucella antibodies. The assay was capable of detecting less than 100 pg brucella antigen in a 20 microliter sample. Experiments in which IgG of non-related specificity was used in place of anti-brucella IgG showed that the test was specific. Normal human serum had only a slight inhibitory effect but anti-brucella antibodies were strongly inhibitory if present in the test sample. The extent of this effect and its relationship to antibody titre was investigated in 12 sera from brucellosis patients.

Antibodies, Bacterial↗

The IgG subclasses of antibodies to grass pollen allergens produced in hay fever patients during hyposensitization.

Total IgG, IgG subclass and IgE antibodies specific for grass pollen allergens were measured by the red cell linked antigen-antiglobulin reaction (RCLAAR) in a serum samples from nineteen patients who had undergone a course of hyposensitization. Increases in both specific IgG and IgE antibodies were seen after treatment in most patients. In the IgG subclasses the predominant response was for IgG1 and IgG4 antibodies. Attempts were made to correlate the antibody responses with the clinical response and the results are discussed with reference to the possible mechanisms of hyposensitization.

Antigen-Antibody Reactions↗

Penicillin allergy studies by a modified red-cell-linked antigen-antiblobulin reaction.

A red-cell-linked antigen-radioactive antiglobulin reaction (RCLA AR) is reported which may be combined with the conventional red-cell-linked antigen-antiglobulin reaction (RCLAAR) to measure antibodies of all five immunoglobulin calsses against the same determinant at the same time. The method has been applied to sera from penicillin-allergic patients and controls. Human erythrocytes coated with rabbit antibodies carrying penicilloyl groups were incubated with the serum to be tested, then washed. 125I-labelled anti-human IgE was added and, after further incubation and washing, the radioactivity retained by the cells was counted. This gives a measure of the specific IgE in the test sample. Other aliquots of the coated cells were treated with specific antiglobulin reagents in the usual manner of the RCLAAR in order to determine antibodies of other classes. The sensitivity for IgE was similar to that of the radioallergosorbent test. Information was also obtained about specific IgG subclasses.

Animals↗

A new immunoassay for C3. Application of the cell-linked antigen radioactive antibody (CLARA) technique.

The cell-linked antigen radioactive antibody (CLARA) method of immunoassay was applied to the C3 component of the complement system. C3 from whole complement was fixed on erythrocytes sensitized with IgM antibody. The IgG1 fractions of monospecific sheep anti-C3 were labelled with 125I and measurement of their specific binding to C3-bearing erythrocytes was used to quantitate the relative amount of fixed C3. Competititive inhibition of this specific binding was used to assay fluid phase C3. 0.3-0.6mug/ml of murine C3 were detected in the supernatant fluid of in vitro cultures of mouse spleen cells.

Animals↗

Polysaccharides as labels for antibodies in electron microscopy.

Two polysaccharides, dextran 250 and dextran 70, were covalently linked to antibody molecules, antihuman immunoglobulin G and antihuman type O red blood cells. In electron microscope preparations exposed to lead citrate, polysaccharides, because they chelate lead, were quite dense. Polysaccharides served as a tag for the antibody molecules. Also, bacterial dextran 1355 was used to demonstrate antibody molecules on the surface of ascites tumor cells which are known to be producing a specific antibody to bacterial dextran 1355. The varying sized polysaccharide molecules that are readily available commercially, the high electron density of the polysaccharides after lead staining and a mild procedure for covalently linking polysaccharide to antibody make polysaccharides attractive as particulate labels for antibody in electronmicroscopy.

ABO Blood-Group System↗