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Biomedical subjects

J A Gold

Publications and source records attributed to J A Gold.

At least 19 recordsLinked to original sources
PubMed1992

Retinoic acid-induced inhibition of metastatic melanoma cell lung colonization and adhesion to endothelium and subendothelial extracellular matrix.

The effect of pretreatment of metastatic B16 melanoma cells with 10(-6) M all trans-retinoic acid resulted in a significant inhibition of lung colonization following injection of 10(5) cells into the tail vein of syngeneic C57BL mice. Adhesion of melanoma cells to vascular endothelial cell monolayers, and subendothelial extracellular matrix was also inhibited by pretreatment with retinoic acid, as was tumour cell aggregation following seeding of pretreated cells on to 0.5% agar. Release of 35SO4 from radiolabelled subendothelial extracellular matrix by melanoma cells was essentially unaltered by retinoic acid pretreatment, as was the release of radiolabel from [3H]proline-labelled matrix, while plasminogen activator activity was enhanced in retinoic-acid-treated cells. These observed changes in adhesive properties may be responsible, at least in part, for the retinoic-acid-induced inhibition of lung colonization.

Animals↗
PubMed1992

Social perceptions of male and female extreme mesomorphs.

In this study, male and female university students in the United States were exposed to mesomorphic or nonmesomorphic stimuli as reflected by photographs of either male body builders and non-body builders or female body builders and non-body builders. Then they were asked to attribute various personality traits and sex-role behaviors to them. Subjects, irrespective of their sex, perceived male and female body builders as possessing more traditionally masculine and less traditionally feminine personality characteristics than male and female non-body builders. Also, male and female body builders were seen as possessing less socially desirable traits than non-body builders. As predicted, female body builders were perceived generally as being more likely to engage in traditionally masculine sex-role behaviors in their dating and marriage relationships than female non-body builders. Contrary to expectation, however, male body builders were not perceived as more likely to engage in higher levels of masculine sex-role behaviors than male non-body builders.

Adult↗
PubMed1989

Modulation of melanoma cell adhesion to basement membrane components by retinoic acid.

The effect of retinoic acid pretreatment on metastatic B16 melanoma cell adhesion in serum-free medium to tissue culture plastic precoated with fibronectin, laminin/nidogen, type I and type IV collagen was examined. Both control cells grown to subconfluence and cells treated with 10(-6) M-retinoic acid adhered and spread rapidly on fibronectin (greater than 75% following 1 h of incubation) but adhered poorly to type I collagen (less than 15%). Control cells adhered to laminin/nidogen (greater than 35%), type IV collagen (greater than 58%) and type IV collagen plus laminin/nidogen (greater than 80%), while retinoic acid-treated cells showed a reduced ability to attach and spread on these substrata, the number of adherent cells being reduced by 61% on laminin/nidogen, by 19% on type IV collagen, and by 41% on type IV collagen plus laminin/nidogen following 1 h of incubation. The minimum concentration of retinoic acid required to yield an effective reduction in adhesion was 10(-7) M for type IV collagen and 10(-10) M for laminin/nidogen. Melanoma cells harvested at low density showed a reduced adhesion to laminin/nidogen and type IV collagen compared to that of subconfluent control cultures, but also showed a reduced adhesion to fibronectin. The effect of retinoic acid on cell adhesion was not, however, due to reduced cell density, as the cells were seeded so that control and retinoic acid-treated cultures were of a similar density when harvested.

Animals↗
PubMed1988

Different susceptibilities of melanoma cells to retinoic acid-induced changes in melanotic expression.

The effect of retinoic acid on murine B16 melanoma cell growth, tyrosinase activity and melanin synthesis was investigated. Retinoic acid inhibited the growth of B16F1, B16F10 and B16BL6 melanoma cells, but enhanced melanin synthesis only in the B16F1 cells. The B16F10 and B16BL6 cells exhibited retinoic acid-induced suppression of tyrosinase activity and melanin synthesis, which was most apparent in the B16F10 cell variant. For comparison, Cloudman S91 melanoma cells proved to be particularly sensitive to retinoic acid-induced growth inhibition and stimulation of the expression of their melanotic phenotype. These results suggest considerable heterogeneity in the B16 melanoma with respect to their response to retinoic acid.

Animals↗
PubMed1984

The intrahepatic and extrahepatic bile ducts in surgical jaundice: radiological evaluation and therapeutic implications.

Many invasive and noninvasive imaging modalities are available to image the biliary tract in suspected surgical jaundice. Technical advances in existing techniques and development of new techniques allow biliary obstruction to be detected in its earliest stages. Criteria for the presence of biliary obstruction include anatomic visualization and measurement of both the intrahepatic and extrahepatic portions of the biliary tree. These criteria will be reviewed and potential diagnostic pitfalls discussed. Anicteric dilatation, disparate dilatation, and segmental obstruction of the biliary tract will be discussed as these entities pose a diagnostic as well as therapeutic challenge. The newer endoscopic and percutaneous interventional techniques will be considered and placed in perspective.

Carcinoma↗
PubMed1983

Acute epiglottitis: current management.

Two hundred and sixty-one cases of acute epiglottitis treated at the Montreal Children's Hospital between 1951 and 1980 are reviewed. Clinical features of the disease are described. Treatment protocol at a major children's hospital is presented. Statistics related to age, season and sex are analyzed. The authors compare nasotracheal intubation and tracheostomy as primary treatment. Bacteriology and antibiotic treatment are updated.

Acute Disease↗
PubMed1982

Ultrasonography and hepatobiliary scintigraphy in the assessment of biliary-enteric anastomoses.

Twenty-three patients with surgical diversion of the biliary tract were serially studied with ultrasonography and hepatobiliary scintigraphy using 99mTc-HIDA or 99mTc-disofenin. Refluxed biliary air resulted in nondiagnostic sonograms in 14% of cases. Persistent postoperative dilatation was present in five patients (22%). Scintigraphy allowed differentiation of biliary dilatation with obstruction from nonobstructed dilatation. By coordinating the noninvasive imaging results, those patients requiring study using direct injection of contrast material may be selected.

Adult↗
PubMed1982

Evaluation of guanabenz added to hydrochlorothiazide therapy in hypertension.

Guanabenz, a centrally acting alpha-adrenergic antihypertensive agent, produces neither the sodium retention seen with other centrally acting agents nor the metabolic abnormalities characteristic of diuretics. In this study, which involved 204 hypertensive out-patients, the additive effects of guanabenz and hydrochlorothiazide were compared with the effects of hydrochlorothiazide therapy alone. Before randomization to the 6-month blinded addition of either guanabenz or placebo, hydrochlorothiazide (50 or 100 mg/day; mean, 70 mg/day) was administered as sole therapy for 6 weeks. During this time, mean supine diastolic blood pressure (SDBP) decreased from 102 to 94 mm Hg (p less than 0.01), with a satisfactory clinical response rate of 62% and a mean weight loss of 2 lbs (p less than 0.01). No further change in mean SDBP occurred during the next 6 months of diuretic therapy, whereas the addition of guanabenz (mean dose, 24 mg/day) caused a further decrease in mean SDBP to 88 mm Hg (p less than 0.01), an increase in the response rate to 86%, and no weight change. Pulse rates in both groups were unchanged. The principal side-effects in both groups were dry mouth, drowsiness, weakness, and dizziness, with a greater incidence of each during the combination therapy. The usual laboratory abnormalities were associated with hydrochlorothiazide. Guanabenz was found to enhance the antihypertensive efficacy of hydrochlorothiazide without compromising its natriuretic properties or producing additional metabolic abnormalities.

Adult↗
PubMed1981

Disparate dilatation of the intrahepatic and extrahepatic bile ducts in surgical jaundice.

Intrahepatic biliary dilatation on ultrasound has been reported as an early sign of biliary obstruction. This paper reports 12 patients with extrahepatic biliary obstruction in whome the extrahepatic biliary system was increased in caliber despite a normal appearance of the intrahepatic ducts. The bile ducts in all of these patients were evaluated with ultrasound and percutaneous transhepatic cholangiography. Computed tomography was performed in one case. The causes of obstructive jaundice included stricture, choledocholithiasis, and neoplasm. The common bile duct provides a sensitive indicator of biliary obstruction, and its demonstration by noninvasive or invasive means is mandatory even when the intrahepatic ducts appear to be normal.

Adult↗
PubMed1981

Acute experimental biliary obstruction in the dog: sonographic findings and clinical implications.

Three dogs were serially studied with sonography after cholecystectomy and total acute biliary obstruction. Peripheral biliary dilatation could be diagnosed as early as 4 hr after biliary obstruction and before significant elevation of serum bilirubin. These experimental results support the thesis that total biliary obstruction may be diagnosed before the onset of icterus.

Alkaline Phosphatase↗
PubMed1981

Underrepresentation of women in new drug trials.

Young women serve less frequently than young men as subjects in premarketing clinical drug trials. Moral, legal, and medical implications of this underrepresentation of women are considered. Risks of medical harm to female patients can increase because medication is withheld. Also, risks of toxicity increase when women receive certain new drugs only in the postmarketing phase. Remedies to increase participation of young, nonpregnant women in clinical trials are discussed.

Clinical Trials as Topic↗
PubMed1981

Tc-99m HIDA scintigraphy in segmental biliary obstruction.

Segmental biliary obstruction as a result of primary or secondary hepatic malignancy has been reported with increasing frequency. For two representative patients, the clinical and Tc-99m HIDA scintigraphic findings in segmental biliary obstruction are described. The presence of photon-deficient dilated bile ducts in one segment of the biliary tree is highly suggestive of localized biliary obstruction and should be considered in the patient with suspected or proven hepatic malignancy despite the absence of jaundice.

Adenocarcinoma↗
PubMed1981

Wiser than the laws?: the legal accountability of the medical profession.

This Article argues that many seemingly disparate questions in health law are related to the issue of how experts are to be held accountable to non-experts--how the principle that decisions should be made by those most affected is to be reconciled with the principle that decisions should be made by those with experience and training in the area. The basic subject matter of health law comprises a number of relationships between medical professionals, on the one hand, and laymen, on the other. In dealing with the proper allocation of decision-making authority within these relationships, the Article considers the social role of medical profession, the theoretical issues in the accountability of expertise, and the nature of medical expertise. On the basis of this discussion, the Article develops principles that can be applied throughout health law.

Humans↗