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Biomedical subjects

R Gibson

Publications and source records attributed to R Gibson.

At least 109 records · Page 6Linked to original sources
PubMed1986

Expectant management of patients with unilateral hepatic duct stricture and liver atrophy.

Three patients with postcholecystectomy unilateral hepatic duct stricture and subsequent liver atrophy were treated conservatively, with a successful outcome of up to three years follow up. A better understanding of the pathophysiological sequelae of segmental hepatic duct obstruction suggests that in such circumstances reconstructive surgery, with its attendant risks, may not invariably be necessary.

Adult↗
PubMed1985

Progressive ossifying myositis in a cat.

Progressive ossifying myositis was diagnosed in a 2-year-old female cat. Clinical signs consisted of cervical pruritus, a stiff gait involving the forelimbs, and decreased range of motion of the scapulohumeral joints. The signs progressed over a 2-month period to involve the hindlimbs and coxofemoral joints. The primary cause of this disease is unknown and treatment is palliative. Treatment with diphosphonate disodium etidronate was unsuccessful in controlling the clinical signs in this case.

Animals↗
PubMed1985

Focal liver lesions: a plan for management.

A management plan for patients with suspected focal liver lesions which avoids early biopsy includes routine laboratory investigations, ultrasound scanning, and assessment for evidence of extrahepatic metastases and non-hepatic primary tumours. Angiography and computed tomography may also be indicated, and laparotomy or laparoscopy is undertaken to assess any potentially resectable focal liver lesions. The plan requires modification to suit individual circumstances.

Biopsy↗
PubMed1982

Spinal cord atrophy associated with arachnoiditis as demonstrated by computed tomography.

Two cases showing the features of spinal arachnoiditis on metrizamide myelography were examined by concurrent computed tomography. This showed severe atrophy and deformity of the spinal cord with its cross sectional shape changing dramatically from one segmental level to the next. These features may be the result of traction on the cord by arachnoid adhesions. Filling defects in the canal or apparent enlargement of the cord may result from pouches of subarachnoid space which are not in free communication with the contrast material.

Arachnoiditis↗
PubMed1982

Cardiovascular and metabolic effects of terbutaline.

Terbutaline is a selective beta 2 agonist used predominantly in the treatment of asthma. Since beta-mediated responses increase heart rate, dilate peripheral arteries, modify carbohydrate metabolism and the uptake of electrolytes into cells, the administration of terbutaline might be expected to produce widespread effects. In this study the intravenous administration of 0.5 mg terbutaline over 60 mn has been shown to produce marked changes without upsetting the volunteers. Heart rate, systolic blood pressure and plasma glucose all increase; diastolic pressure and serum potassium decrease. The data suggests that the terbutaline infusion may be a useful tool for the investigator. The results also quantitate some of the side effects which may result from the intravenous administration of a therapeutic dose of terbutaline given to asthmatics or to pregnant women to reduce uterine activity and delay childbirth.

Adult↗
PubMed1982

Effectiveness of high-frequency jet ventilation in management of an experimental bronchopleural fistula.

An animal model was prepared to compare the effectiveness of high-frequency jet ventilation (HFJV) with that of conventional intermittent positive pressure ventilation (IPPV) in managing bronchopleural fistula. In ten adult beagles, the left upper pulmonary lobe was resected and the left upper lobe bronchus was cannulated to establish a permanent bronchopleural fistula. Apposition of the middle lobe to the chest wall was examined via an open thoracotomy. Fistula leakage was measured with the thoracotomy closed, and chest tube drainage was set at 20 cm H2O. With HFJV, lung apposition was attained at lower peak (8.9 cm H2O) and expiratory (5.7 cm H2O) pressures than with IPPV (21.2 cm H2O Peak pressure and 10.7 cm H2O expiratory pressure). With equivalent arterial blood gases, fistula leakage was 47 per cent higher with IPPV than with HFJV (P less than .001). Each 5 cm of positive end expiratory pressure (PEEP) added increased fistula leakage similarly to both systems. Varying the frequency of HFJV did not alter leakage significantly, but increasing the driving pressure markedly increased leakage. Thus, experimentally, HFJV proved superior to IPPV in the management of bronchopleural fistula. When HFJV is used clinically to manage a bronchopleural fistula, the driving pressure should be kept as low as possible and PEEP should be limited. The ventilatory rate may be varied to achieve the desired PaCO2 without significantly affecting leakage through the fistula.

Animals↗
PubMed1982

Microbial hazards associated with bean sprouting.

The behaviour of microorganisms was studied in mung beans and alfalfa seeds before and after germination in modified, commercially available bean-sprouting kits. The microorganism were enumerated by the aerobic plate count (APC) and by total yeast and mold count procedures. Salmonella species were artificially inoculated into selected samples and were enumerated by the most probable number (MPN) method. After germination of the beans or seeds into mature sprouts, significant increases were noted in APCs and in MPN values of Salmonella species. Although counts of yeasts and molds did not increase significantly after germination, these samples show an increase in toxic Aspergillus flavus and potentially toxic Alternaria species. The presence of toxic Penicillium cyclopium molds also increase substantially in 5 samples of a single brand of mung beans. Analysis of selected sprout samples, however, showed no presence of aflatoxin.

Aflatoxins↗
PubMed1981

The effect of oligosaccharide chains of different sizes on the maturation and physical properties of the G protein of vesicular stomatitis virus.

The envelope glycoprotein, G, of vesicular stomatitis virus (VSV) is initially glycosylated by the en bloc transfer of Glc3Man9GlcNAc2 oligosaccharides to 2 specific asparagine residues in the nascent polypeptide chain. We carried out in vivo and in vitro studies to determine whether the size of the oligosaccharide chains on two related but different G proteins can affect their ability to fold correctly. For the in vivo studies we used a mutant lymphoma cell line, Thy-1-e, which transfers the truncated oligosaccharide, Glc3Man5GlcNAc2, to nascent polypeptides. The growth of VSV in these cells was temperature-sensitive compared to that in parental Thy-1+ cells, and VSV (San Juan) was more affected than VSV (Orsay). These results are congruous with our previous observation that in the absence of glycosylation virus assembly is temperature-sensitive and VSV (San Juan) is inhibited more than VSV (Orsay). To examine the effect of oligosaccharide size on the properties of the G protein in vitro we treated G proteins containing either Man8GlcNAc2 or Man5GlcNAc2 oligosaccharide chains with guanidine hydrochloride and measured their ability to refold using an in vitro aggregation assay. The San Juan G protein with Man5GlcNAc2 oligosaccharides aggregated at 40 degrees C but not at 30 degrees C. The Orsay G protein with Man5GlcNAc2 oligosaccharides and both proteins containing Man8GlcNAc2 oligosaccharides did not aggregate at either temperature. We conclude that the size of the oligosaccharides present on the folding G protein can be crucial in attaining a proper conformation, and the extent of their effect depends on the primary structure of the polypeptide.

Animals↗
PubMed1981

Congenital coronary artery obstruction associated with aortic anomalies in children: report of two cases.

Coronary arterial obstruction associated with congenital aortic valve disease is rare in children. We studied two children with aortic valve disease and symptoms of coronary insufficiency. Cineangiography revealed localized obstruction of the proximal left coronary artery. In one patient, a membrane-like structure partially covered the left sinus of Valsalva, almost isolating the ostium of the left coronary artery; the other patient had severe stenosis of the proximal left coronary artery and a congenitally hypoplastic left coronary cusp. Surgical repair was successful in both cases. Symptoms of myocardial ischemia in children with aortic valve disease should be investigated promptly to exclude obstruction of the coronary arteries.

Aortic Valve↗
PubMed1981

Atropine suppresses gastrin release by food intact and vagotomized dogs.

We have demonstrated that at doses lower than those used by others in dogs, atropine consistently inhibited food-stimulated gastrin release irrespective of vagal innervation of the stomach. Gastrin release induced by food placed directly into the stomach was studied in four gastric fistula dogs with intact vagi and in three other similar dogs with fundic vagotomy. The studies were repeated in dogs after conversion to truncal vagotomy. Fasting serum gastrin was lower in the intact dogs (33 +/- 1.7 pg/ml) than after fundic vagotomy (61 +/- 13 pg/ml) or truncal vagotomy (97 +/- 20 pg/ml). The same relationship held for absolute postprandial values. However, the integrated gastrin response to food over 2 h was similar in the three groups of dogs (intact 14 +/- 4.6, fundic vagotomy 10.3 +/- 4.3, truncal vagotomy 17.4 +/- 2.4 ng.min/ml). Regardless of the state of gastric vagal innervation atropine 20 microgram/kg . h reduced gastrin releases due to food by 66-76% (p less than 0.05) in all three groups. In small doubling doses (1-16 microgram/kg), atropine given i.v. at 15-min intervals, dose-responsively inhibited food-stimulated gastrin release in the four dogs with intact vagi. Assuming that the atropine effect was cumulative, kinetic analysis of the dose-response data gave a calculated maximum inhibition of 91% and an ID50 of 5.1 microgram/kg or 7.2 X 10-9 mol/kg. Findings of this study indicate a previously undescribed muscarinic cholinergic pathway leading to gastrin release by food.

Animals↗
PubMed1981

The comparative electrophysiologic and hemodynamic effects of verapamil in puppies and adult dogs.

Verapamil has been studied extensively in adult animals. However, there is limited data about the effects of this antiarrhythmic agent in young animals. We studied the electrophysiologic and hemodynamic effects of verapamil in 5 awake, chronically instrumented puppies and in 6 anesthetized, acutely instrumented puppies. We compared the responses in puppies to those in 7 awake, chronically instrumented adult dogs and in 6 anesthetized, acutely instrumented adult dogs. In the awake, chronically instrumented animals, we measured heart rate and the effective refractory period of the atrio-ventricular specialized conduction system (ERP-AVSCS). In the anesthetized, acutely instrumented preparation, we measured heart rate, ERP-AVSCS, mean right atrial and systemic arterial blood pressure, and velocity of blood flow in the aorta, carotid and femoral arteries. We infused verapamil intravenously at doses of 50, 100, 200 and 400 microgram/kg. Verapamil (400 micrograms/kg) increased the ERP-AVSCS by 64% in awake, chronically instrumented puppies; 62% in awake, chronically instrumented adult dogs; 125% in anesthetized, acutely instrumented puppies, and 120% in anesthetized, acutely instrumented adult dogs. The effect of verapamil upon heart rate and ERP-AVSCS was more pronounced in anesthetized animals than in awake animals. Mean systemic arterial blood pressure was reduced by verapamil in anesthetized, acutely instrumented puppies and adult dogs. Verapamil reduced the velocity of aortic, femoral and carotid artery blood flow in anesthetized, acutely instrumented puppies.

Aging↗
PubMed1978

Synthesis and infectivity of vesicular stomatitis virus containing nonglycosylated G protein.

The replication of vesicular stomatitis virus (VSV) is inhibited by tunicamycin (TM), an antibiotic that blocks the formation of N-acetylglucosaminelipid intermediates. We had shown previously that the viral glycoprotein (G) synthesized in cells treated with TM is not glycosylated and is not found on the outer surface of the cell plasma membrane. In this report, we shown that cells exposed to TM produce a low yield of infectious particles. The yield is increased when the temperature during infection is lowered from 37 to 30 degrees C. At 30 degrees C in the presence of TM, both wild-type VSV and the temperature-sensitive mutant ts045 produce particles that do not bind to concanavalin A Sepharose and contain only the nonglycosylated form of G. These particles have a specific infectivity (pfu/cpm) comparable to that of VSV containing glycosylated G.

Anti-Bacterial Agents↗
PubMed1978

Emergencies in dialysis patients.

Specific emergencies occur in patients maintained on hemodialysis that often require evaluation and treatment in the emergency department, including infection of the access, cardiovascular disease, blood pressure abnormalities, pericarditis, cardiac arrhythmias and headache. Specific recommendations for treatment are presented.

Arteriovenous Shunt, Surgical↗