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Biomedical subjects

A J Scott

Publications and source records attributed to A J Scott.

At least 55 records · Page 3Linked to original sources

Dihydrocholesterol-induced gallstones in the rabbit: evidence that bile acids cause gallbladder epithelial injury.

Rabbits fed a diet containing 0.75% dihydrocholesterol for 7 days develop bile acid allodeoxycholic (ADCA) and deoxycholic acid (DCA) stones in the gallbladder. In this model, inflammatory changes in the gallbladder mucosa are often observed even before stones are formed. Within 3 days of the lithogenic diet, abnormalities of platelet function were detectable. Platelet aggregation upon addition of adenosine diphosphate (ADP) was impaired. At the same time the red cells became crenated and developed thorny spicules (echinocytes). This morphological changes was associated with intracellular dehydration and excessive loss of potassium. These changes coincided with a rise in serum ADCA and DCA and preceded a slow rise in serum cholesterol. In vitro incubation studies also suggested that the bile acids had probably caused membrane injury to the platelets and red cells. It is concluded that changes in the bile ADCA and DCA probably induce gallbladder epithelial injury in this model of experimental cholelithiasis.

Animals↗

Epithelial cell proliferation in diverse models of experimental cholelithiasis.

Proliferation of the epithelial cells of the gall bladder during the initial stages of experimental cholelithiasis has been studied by autoradiography. Rabbits taking a diet with 1% dihydrocholesterol added showed a rise in labelling index from 1.5%-19% by three days. Mice taking a 1% cholesterol 0.5% cholic acid diet showed a similar rise from less than 1% to 15-21% at two and five days. Guinea-pigs receiving lincomycin showed a rise from less than 1% to 6% after 24 hours. These changes, which appear well before the appearance of gall stones, together with previous reports of enhanced mucous secretion during lithogenesis, make it clear that in these laboratory models of cholelithiasis the gall bladder is abnormal well before stones form.

Animals↗

Benign postoperative jaundice complicating severe trauma.

Five patients are described in whom deep jaundice developed following severe trauma. Only two of the patients showed acute renal failure. All showed the adult respiratory distress syndrome. The livers at autopsy were enlarged and showed centrilobular congestion and cholestases. This syndrome, which is closely analogous, to that described as "benign postoperative jaundice", is more closely associated with the hypoxic hypoxia of acute respiratory failure than with the stagnant hypoxia of acute circulatory failure. It is accentuated by transfusion, and often by disseminated intra-vascular coagulation.

Adolescent↗

TMJ dysfunction--principles of the clinical examination.

Determining if head pain is related to occlusal disharmony can be a challenge. A brief outline of the clinical examination of these patients was presented. Gross interceptive occlusal contacts should be corrected in all patients. The evaluation of signs and symptoms is the basis for determining whether to "adjust" the asymptomatic patient. Consideration should be given to the intensity of the occlusal disharmony, the level of anxiety, and the patient's adaptive response.

Dental Occlusion, Balanced↗

Diazoxide-induced renin release in diagnosis of remediable renovascular hypertension.

In hypertensive patients with unilateral renal artery stenosis, intravenous diazoide increased renal vein renin activity more on the involved side than on the contralateral side, whereas, in a group with predominantly unilateral renal parenchymal disease, the increase in renal vein was similar for both kidneys. In patients with bilateral renal artery stenosis, the use of diazoxide was helpful in lateralizing the dominant ischaemic lesion. Diazoide administration appears to be a safe, rapid and convenient method of increasing the sensitivity of the renal vein renin test used in predicting the outcome of surgical treatment of renovascular hypertension. Bilateral renal vein renin determination of established value in the diagnosis of functional renal ischaemia. 1-4 However, in the use of this procedure to predict the efficacy of corrective surgery, false positive and false negative results still occur. Thus, various manoeuvres which stimulate renin release have been employed to improve the sensitivity of the test. 5-7 We report a new application the practical approach to of this procedure in the diagnosis of renal hypertension, which both basal and stimulated levels of renal venous renin activitity can be measured during a brief period of bilateral renal vein catherization.

Adolescent↗

Lincomycin-induced cholecystitis and gallstones in guinea pigs.

Guinea pigs given lincomycin 60 mg per kg per day showed a striking increase in the renewal of epithelial cells in the gallbladder. This was detectable after only 24 hr of treatment. By 48 hr a precipitate consisting predominantly of calcium and bilirubin had formed in the gallbladder. Gallbladder bile glycoprotein concentrations rose progressively. At 8 days epithelial dysplasia was marked. Treatment was discontinued at 9 days. The guinea pigs that survived beyond 34 days showed that new tubuloalveolar glands had formed focally in the body and fundus of the gallbladder. Multiple calcium-containing stones were present. The failure to culture bacteria from bile, the failure of the bile salt pattern to change, and the progressive nature of the epithelial injury suggested that the changes resulted from a direct toxic effect and were not dependent on the antibiotic activity of this drug. It was concluded that damage to the epithelium of the gallbladder preceded the formation of a precipitate and initiated histological changes which culminated, at the time that the precipitate became organized into stones, in impressive glandular metaplasia.

Animals↗