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Biomedical subjects

R Wilson

Publications and source records attributed to R Wilson.

At least 505 records · Page 28Linked to original sources
PubMed1990

Bupivacaine with and without epinephrine for intercostal nerve block.

In a double-blinded study, 15 American Society of Anesthesiologists class I or II patients, following lateral thoracotomy with general anesthesia, were randomized into two groups for intercostal nerve block with either bupivacaine, 0.5%, and epinephrine, 1:200,000, or plain bupivacaine, 0.5%. Blood concentrations of bupivacaine, epinephrine, and norepinephrine were serially measured. Blood pressure, heart rate, respiratory rate, temperature, and electrocardiogram were monitored. Peak blood bupivacaine concentrations were significantly lower in patients receiving bupivacaine with epinephrine. Peak epinephrine concentrations were significantly greater in patients receiving bupivacaine with epinephrine, but still within a safe range. No significant differences were seen in heart rate, blood pressure, respiratory rate, or temperature between the two groups, and/no dysrhythmias occurred. Peak norepinephrine concentrations were not significantly different between the two groups. The potential risk of toxic bupivacaine blood concentrations associated with intercostal nerve blocks can be reduced by the addition of epinephrine at a concentration of 1:200,000.

Absorption↗
PubMed1990

Transperitoneal versus retroperitoneal approach for aortic reconstruction: a randomized prospective study.

A prospective, randomized study was conducted to compare the retroperitoneal versus transperitoneal approach for elective aortic reconstruction. One hundred thirteen patients (transperitoneal = 59, retroperitoneal = 54) were randomized between March 1987 and October 1988. In addition, to assess the changing course of patients undergoing aortic reconstruction similar data were gathered retrospectively on a group of 56 patients undergoing aortic reconstruction by the same surgeons performed via a transperitoneal approach in 1984 to 1985. Randomized patients were identical in age, male to female ratio, smoking history, incidence and severity of cardiopulmonary disease, indication for operation, and use of epidural anesthetics. Details of operation including operative and aortic cross-clamp times, crystalloid and transfusion requirements, degree of hypothermia on arrival at the intensive care unit, and perioperative fluid and blood requirements did not differ significantly for patients undergoing transperitoneal versus retroperitoneal reconstruction. Respiratory morbidity, as assessed by percent of patients requiring postoperative ventilation, deterioration in pulmonary function tests, and the incidence of respiratory complications, was identical in randomized patients. Other aspects of postoperative recovery including recovery of gastrointestinal function, the requirement for narcotics, metabolic parameters of operative stress, the incidence of major and minor complications, and the duration of hospital stay were similar for randomized patients undergoing transperitoneal and retroperitoneal reconstruction. When compared to retrospectively reviewed patients having aortic reconstruction, randomized patients undergoing transperitoneal and retroperitoneal operations had highly significant (p less than 0.001) reductions in postoperative ventilation, transfusion requirements, and length of hospital stay. Such trends were all independent of transperitoneal versus retroperitoneal approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1990

Proinflammatory interactions of pyocyanin and 1-hydroxyphenazine with human neutrophils in vitro.

The effects of the Pseudomonas aeruginosa-derived pigments, pyocyanin and 1-hydroxyphenazine (1-hp), on membrane-associated oxidative metabolism and release of lysozomal enzymes by human neutrophils were investigated in vitro. Pyocyanin, but not 1-hp, increased the generation of superoxide and the rate and duration of oxygen uptake by activated neutrophils. Both agents increased the myeloperoxidase-mediated iodinating activity of neutrophils, which in the case of 1-hp was due to stimulation of the release of myeloperoxidase by activated neutrophils. 1-hp also increased the release of lysozyme by activated neutrophils. Pyocyanin caused only slight enhancement of the release of myeloperoxidase and lysozyme by stimulated neutrophils but was more potent with respect to the release of the specific granule marker, vitamin B12-binding protein. These data indicate the existence of diverse, proinflammatory interactions of pyocyanin and 1-hp with human phagocytes, which may intensify neutrophil-mediated tissue damage during P. aeruginosa infections.

Cell Degranulation↗
PubMed1990

UK-52,046 (a novel alpha 1-adrenoceptor antagonist) and the role of alpha-adrenoceptor stimulation and blockade on atrioventricular conduction.

The effects of increasing intravenous (i.v.) doses of prazosin, phenylephrine, flecainide, and UK-52,046 on blood pressure (BP), heart rate (HR) and the specialized conduction system (AH and HV intervals) were investigated in anaesthetized dogs. Results indicated that UK-52,046 (1-8 micrograms/kg) had no effect on BP or HR, but reduced (p less than 0.05) BP at doses of 16 and 32 micrograms/kg; no change occurred in HR. During sinus rhythm (SR) the AH or HV intervals did not change as compared with placebo; on pacing (PA) UK-52,046 (4-16 micrograms/kg) decreased the AH interval. After prazosin BP decreased (p less than 0.05) after 20-40 micrograms/kg; HR increased after all doses (5-40 micrograms/kg). The HV interval was unaltered, but the AH interval decreased after 40 micrograms/kg during SR and PA. After phenylephrine (continuous infusion, 50 micrograms/ml/min) BP increased at 33 min and HR was decreased at 23 and 33 min. The AH interval lengthened during PA (p less than 0.05), but there was no effect on the HV interval. Administration of flecainide (0.5-2.0 mg/kg) had no effect on BP or HR but increased the HV interval during SR and PA (1 and 2 mg/kg, p less than 0.05). The results indicate that the alpha 1-adrenoceptor agonist phenylephrine and the alpha 1-adrenoceptor antagonist prazosin, on PA altered the AH (but not the HV) intervals in opposite directions in association with changes in HR and BP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1990

Effect of lignocaine on coronary blood flow, systolic myocardial function and myocardial high energy phosphate stores in swine.

1. To investigate the effect of lignocaine upon coronary blood flow, myocardial systolic wall function and high energy phosphate stores, lignocaine was administered as a rapid intravenous injection to 14 open chest anaesthetized swine. 2. Before and after injection, measurements were made of coronary blood flow by electromagnetic flow probe, per cent wall thickening by ultrasonic crystals, adenosine triphosphate (ATP) and creatine phosphate (CP) content by myocardial biopsy, and arterial pressure by central aortic catheter. The animals were divided into two groups based on whether or not they received a continuous low-dose infusion of lignocaine prior to the study. Group I received the continuous low-dose infusion of lignocaine and group II did not. 3. With a 2 mg/kg lignocaine injection, peak diastolic coronary flow rose significantly in groups I and II by 27 +/- 7 and 29 +/- 7% respectively. This was followed by a significant decline in per cent wall thickening in groups I and II of -11 +/- 2 and -19 +/- 6% respectively. In group I myocardial CP content decreased after lignocaine injection by 58 +/- 6% and ATP tended to rise even though systolic and diastolic pressure did not change significantly. In group II neither CP nor ATP changed significantly, but systolic and diastolic blood pressure decreased significantly. 4. Repeat lignocaine injections were given over a wider dosage range (0.5-4.0 mg/kg) to determine dose-response for lignocaine versus coronary blood flow. Coronary blood flow increased and per cent wall thickening decreased as doses of lignocaine were increased. 5. It was concluded that rapid intravenous lignocaine injection appeared to cause a dose-dependent coronary dilatation and systolic dysfunction. Pre-treatment with low-dose continuous infusion of lignocaine appeared to result in a decrease in CP and a rise in ATP when compared with no pre-treatment--despite a similar effect on myocardial function and coronary blood flow.

Adenosine Triphosphate↗
PubMed1990

Free radical activity in type 2 diabetes.

Free radical activity has been implicated in the development of diabetic vascular complications in Type 1 diabetes. The aim of the present study was to investigate the levels of free radical scavengers, particularly erythrocyte superoxide dismutase, plasma and erythrocyte lysate thiol, and caeruloplasmin in 22 Type 2 diabetic patients clinically free of complications, and 15 comparable non-diabetic control subjects. The concentration (median (range] of both superoxide dismutase (23 (10-39) vs 45 (25-75) mumol l-1; p less than 0.001) and plasma thiol (374 (172-523) vs 460 (386-595) mumol l-1; p less than 0.01) were reduced in the diabetic group. There were no significant differences in the concentration of erythrocyte lysate thiol (199 (114-520) vs 188 (114-328) mumol l-1) or plasma caeruloplasmin (18 (9-31) vs 24 (6-50) mumol l-1) between the groups. This reduction in superoxide dismutase and the imbalance in the redox status of the plasma and lysate thiol demonstrated is consistent with an increase in free radical activity in Type 2 diabetes.

Blood Glucose↗
PubMed1990

In vitro and in vivo effects of ribavirin on human respiratory epithelium.

The effects of ribavirin, a broad spectrum antiviral agent, on the structure and function of normal human nasal epithelium have been studied in vitro, as has also the in vivo effect of treatment with nebulised ribavirin on nasal mucociliary clearance of saccharin in four patients. Ciliary beat frequency was measured by a photometric technique, and changes in epithelial and ciliary ultrastructure were assessed by transmission electron microscopy. Ribavirin solution at the recommended concentration of 20 mg/ml had no adverse effects on ciliary activity in vitro; at concentrations of 50 mg/ml and above it slowed ciliary beating significantly and at 60 mg/ml caused ciliostasis associated with epithelial disruption. Nasal inhalation of ribavirin at 60 mg/ml for up to 20 minutes, however, did not slow nasal mucociliary clearance, nor did it adversely affect the ciliary beating or structure of nasal ciliated epithelium examined in vitro immediately after inhalation.

Aged↗
PubMed1990

Effect of bacterial products on neutrophil migration in vitro.

Chronic bronchial inflammation is associated with migration of large numbers of granulocytes into the bronchial tree. A study was designed to find out whether products of bacteria commonly isolated in chronic bronchial infection stimulate neutrophil migration in vitro. Neutrophils from healthy donors were studied by a modified Boyden chamber technique. Bacterial culture filtrates stimulated neutrophil migration over a wide dilution range and the chemotactic activity was heat stable. Culture filtrates derived from Pseudomonas aeruginosa, Streptococcus pneumoniae, and Haemophilus influenzae were significantly chemokinetic and directionally chemotactic, whereas filtrates from Staphylococcus aureus were only chemotactic. Gel filtration of S aureus and P aeruginosa culture filtrates yielded high, medium, and low molecular weight fractions showing chemotactic activity. S pneumoniae and H influenzae yielded fractions with only low molecular weight chemotactic activity. Neutrophil chemotactic responses, occurring in response to all bacterial species tested, appear to represent a defence mechanism by the host. Chemoattractant activity may, however, contribute to bronchial damage mediated by products released from continuously attracted, activated neutrophils.

Bacteria↗
PubMed1990

The effects of activated eosinophils and neutrophils on guinea pig airway epithelium in vitro.

Epithelial shedding is a characteristic feature of asthmatic airways and has been attributed to eosinophil products. We have examined the interaction of purified intraperitoneal guinea pig eosinophils with or without platelet-activating factor (PAF, 10(-7) M) or lyso-PAF (10(-7) M) with guinea pig tracheal epithelium in vitro. At 0, 4, 14, and 24 h, the percentage of ciliation of the tracheal circumference (CTC) was measured by light microscopy and the ciliary beat frequency (CBF) by photometry. PAF-activated eosinophils (50 x 10(6) cells/ml) disrupted the epithelium, mean CBF and CTC being reduced by 77.8 +/- 5.8% (mean +/- SEM; P less than 0.001 versus control) and 94.2 +/- 1.4% (P less than 0.001) over 24 h, respectively. PAF (10(-7) M) alone had no significant effect. Lyso-PAF with eosinophils (50 x 10(6) cells/ml) also reduced mean CBF and CTC but to a lesser extent. Eosinophils alone also led to a reduction of 36.2 +/- 11.4% in mean CBF and 53.0 +/- 15.5% in CTC, but these changes were not significant. The PAF antagonist, WEB 2086 (10(-6) M), significantly inhibited the mean CBF and CTC reduction due to PAF-activated eosinophils by 61.5 +/- 17.2% (P less than 0.01) and 20.8 +/- 6.5% (P less than 0.05), respectively. In addition, catalase (1,125 U/ml) partially inhibited the mean CBF and CTC reduction induced by PAF-activated eosinophils. Intraperitoneal neutrophils (PMN) (50 x 10(6) cells/ml) also disrupted epithelium but to a lesser extent (24-h reduction: 34.2 +/- 12.7% for mean CBF and 60.2 +/- 13.2% for CTC, respectively). Stimulation with PAF (10(-7) M) had no further effect. Marked exfoliation of the epithelial layer was observed after 14 h of incubation with activated eosinophils. We concluded the PAF-activated eosinophils are capable of grossly disrupting ciliated epithelium and may contribute to epithelial damage observed in asthma.

Animals↗
PubMed1990

Acute effect of lidocaine on coronary blood flow and myocardial function.

The acute effects of lidocaine on coronary blood flow, hemodynamic parameters, and wall function were studied in 14 anesthetized pigs. Lidocaine was infused intravenously as a bolus (dosage range from 1.5 to 4.0 mg/kg). At ten to thirty seconds after infusion, coronary blood flow reached 154 +/- 38% (mean +/- SD) of the baseline resting flow (p less than 0.001). The double product, an estimate of myocardial oxygen demand, decreased from a baseline value of 9221 +/- 2174 to 8008 +/- 1923 mmHg beats/min (p less than 0.01). Sixty seconds postinfusion myocardial function decreased from baseline wall thickening of 46 +/- 25% to 41 +/- 17% (p = 0.04). An acute bolus of lidocaine appears to transiently increase coronary blood flow, by decreasing coronary vascular resistance, and also decrease myocardial function. Thus, an acute lidocaine bolus may favorably alter the myocardial oxygen supply/demand ratio.

Animals↗
PubMed1990

Thyrotropin receptor antibodies associated with post-operative relapse of thyrotoxicosis in a pregnancy complicated by neonatal thyrotoxicosis.

This case describes the clinical, biochemical and immunological features associated with relapse of thyrotoxicosis during pregnancy in a patient who had recently undergone a subtotal thyroidectomy for Graves' disease. The baby, shortly after birth, showed clinical and biochemical features of thyrotoxicosis which responded to carbimazole therapy. Thyrotropin receptor antibodies and thyroid stimulating antibodies were present in the blood of the mother and baby. The clinical course of the neonatal thyrotoxicosis correlated with the TSH receptor antibody levels.

Adult↗
PubMed1990

Ophthalmopathy in early thyrotoxicosis--relationship to thyroid receptor antibodies and effects of treatment.

A prospective study of 25 newly diagnosed thyrotoxic patients was undertaken to determine the incidence and severity of ophthalmopathy in the early stages of the disease. A quantitative analysis of the ocular muscle changes was made using B scan ultrasonography, and the effects of treatment for the thyroid disease on the course of the eye changes was assessed. Although the majority (75%) of patients showed only mild clinical signs of ophthalmopathy (Werner Class 3 or less), 92% had ultrasonographic evidence of ocular muscle enlargement. Clinical involvement of the extraocular muscles was seen in 12% of the cases. There was an inverse correlation between the serum level of thyroid stimulating hormone receptor antibody (TR Ab) and the size of the extraocular muscles. Recovery of the euthyroid state with treatment was accompanied by a decrease in orbital infiltration in some cases, both clinically (reduced amplitude of intraocular pressure rise on elevation of the globe) and by ultrasonography, but the improvement was not statistically significant.

Adolescent↗
PubMed1990

The incidence of clinical thyroid dysfunction in an unselected group of pregnant and post partum women.

This study has examined the incidence of thyroid dysfunction during pregnancy and up to six months post partum in 65 women attending an antenatal clinic in the West of Scotland. Five were found to be positive for thyroid antibodies at presentation and in these the antibody titre fluctuated during pregnancy and in the post partum period. One patient developed thyroglobulin antibodies post partum. Mean total T3 and total T4 levels rose during pregnancy but had normalised by six weeks post partum. The changes in FT4 and TBG levels observed during pregnancy did not normalise until after six weeks post partum. Only one patient developed any biochemical evidence of thyrotoxicosis post partum and this was not found to be associated with the presence of thyroid antibodies. No patient showed any evidence of hypothyroidism.

Adult↗
PubMed1990

The effects of antithyroid drugs on intercellular mediators.

The antithyroid drugs methimazole and propylthiouracil have been shown to affect the function of monocytes and B and T lymphocytes in vitro. The aim of this study was to investigate the mechanism responsible for signalling between these various cell types. Propranolol, a drug known to have no effect on the immune system, was also included as a control against which the effects of the other drugs could be monitored. Peripheral blood lymphocytes from control subjects were stimulated with phytohemagglutinin in the presence or absence of antithyroid drugs. Propranolol was found significantly to inhibit beta 2 microglobulin production. In addition it was also found to be a very weak scavenger of free oxygen radicals. Methimazole significantly increased interleukin 2 levels (p less than 0.01), but had no significant effect on either gamma-interferon or beta 2 microglobulin production. Propylthiouracil also increased interleukin 2 levels (p less than 0.001) and significantly decreased beta 2 microglobulin production (p less than 0.01). Both drugs were found to be scavengers of free O2 radicals. It would appear that IL-2 is involved in intercellular signalling and this process may involve free radicals.

Cell Communication↗
PubMed1990

The effect of pre-operative potassium iodide therapy on antibody production.

Previous studies have suggested that iodide may increase the incidence of thyroid disease and anti-thyroid antibodies in predisposed individuals. This study has considered the effects of pre-operative potassium iodide (60 mg twice daily, for 10 days) on the immune system of patients with Graves' disease. The treatment regimen used maintained all patients in a clinically and biochemically euthyroid state prior to surgery. Potassium iodide significantly increased serum thyrotropin receptor antibody levels and B cell activity as determined by increased immunoglobulin production from mitogen stimulated peripheral blood lymphocytes. These effects were not observed in the two control groups of Graves' disease patients. Our in vivo findings would support previous in vitro work showing that potassium iodide does act on the immune system and this may be the mechanism by which iodide induces thyroid dysfunction in predisposed individuals.

Antibody Formation↗
PubMed1990

The behaviour of suppressor-inducer T cells following treatment for Graves' disease.

The expression of surface markers of T cell subsets in the peripheral blood of 30 Graves' disease patients was investigated pre and post therapy using two colour flow cytometry. Reduced numbers of total, helper/inducer and suppressor/cytotoxic T cells were found in untreated Graves' patients. Numbers of suppressor-inducer T cells which are associated with maintaining the normal immune response, did not differ significantly between untreated Graves' patients and controls. Although 8 weeks' Carbimazole therapy reversed the changes in total, helper/inducer and suppressor/cytotoxic T cells, PTU or 131I therapy did not. While suppressor-inducer T cell numbers were not affected by Carbimazole or PTU therapy, 131I treatment caused a decrease in suppressor-inducer T cell numbers.

Carbimazole↗
PubMed1990

The effect of carbimazole therapy on interleukin 2, interleukin 2 receptors and free radicals.

Levels of Interleukin 2 (IL2), IL2 receptors (IL2R) and free radical scavengers were measured in 25 Graves' disease patients prior to and following an 8 week course of Carbimazole therapy in an attempt to understand the mechanism by which the drug acts on the immune system. In untreated Graves' patients IL2R levels were elevated and IL2 levels reduced. Free radical scavengers were also reduced in these patients. Following treatment IL2R levels fell and IL2 levels rose. Levels of the free radical scanvengers also rose. It is not clear whether it is the fall in IL2R levels or the rise in the level of free radical scavengers (implying a reduction in free radical activity) which is responsible for the rise in IL2.

Carbimazole↗