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Biomedical subjects

J Hamilton

Publications and source records attributed to J Hamilton.

At least 217 records · Page 12Linked to original sources
PubMed1977

Macrophage plasminogen activator: induction by concanavalin A and phorbol myristate acetate.

The synthesis and secretion of plasminogen activator by cultured macrophages can be induced and stimulated by concanavalin A and by phorbol myristate acetate, and inhibited by such agents as glucocorticoids, mitotic inhibitors and compounds affecting cAMP metabolism. By the manipulation of stimulatory and inhibitory influences, enzyme production can be modulated continuously over a 200 fold range. In the same way, the proportion of cells that secrete detectable levels of enzyme can be varied from 1-90%. No comparable modulation of lysozyme or acid hydrolase production is observed under the same conditions. These results suggest that the physiological control of macrophage plasminogen activator production is achieved by the interacting effects of mutually antagonistic stimuli; this emphasizes the utility of this enzyme for the study of regulatory phenomena, including those relating to inflammation.

Bacterial Toxins↗
PubMed1976

Macrophage plasminogen activator: induction by asbestos is blocked by anti-inflammatory steroids.

Intraperitoneal injection of asbestos fibres into mice induces the formation of exudates containing macrophages that produce plasminogen activator. Like-wise, in vitro addition of asbestos to macrophage cultures stimulates plasminogen activator secretion; the synthesis and secretion of lysozyme and lysosomal enzymes are not changed under these conditions. The enhanced secretion of plasminogen activator by macrophages exposed to asbestos is suppressed by low concentrations of anti-inflammatory steroids.

Animals↗
PubMed1976

Repair of the dorsal apparatus of the finger.

This paper describes a simple method of assessing the constituent features of flexion deformities of the proximal interphalangeal joints in Hansen's disease, and a simple operation to correct the anterior displacement of the lateral band and the associated contractures.

Fingers↗
PubMed1976

Macrophage plasminogen activator: modulation of enzyme production by anti-inflammatory steroids, mitotic inhibitors, and cyclic nucleotides.

Plasminogen activator production by cultured mouse peritoneal macrophages can be modulated in vitro by low concentrations of various pharmacologically active molecules. Glucocorticoid hormones and their synthetic derivatives, as well as cholera toxin, colchicine, and vinblastine markedly inhibit production of this enzyme without affecting other important macrophage functions. The effect of glucocorticoids is of particular interest, both because their relative in vivo anti-inflammatory potencies correlate exactly with their effect on plasminogen activator production in culture and because this effect occurs at near physiological concentrations. In view of the correlations established in other systems between plasminogen activator production and cell migration, we have also examined the age of the macrophages in thioglycollate-induced exudates. Confirming the results of Van Furth and Cohn (1968), we have found that the majority of these cells are young, having recently replicated and arrived in the peritoneal cavity. Using a fibrinagar overlay technique which allowed us to determine the production of plasminogen activator by individual cells. we have found that the majority of these cells produce the enzyme. The potential roles of plasminogen activator in monocyte migration and the relationship of this enzyme to the anti-inflammatory effect of gluccorticoids are correlated and emphasized.

Animals↗
PubMed1976

Correlation of endoscopy and double-contrast radiography in the early stages of ulcerative and granulomatous colitis.

Early radiological changes in ulcerative colitis include (a) finely granular mucosa due to hyperemia and edema, (b) mucosal stippling due to adherence of barium to superficial ulcers, and (c) coarsely granular mucosa due to ingrowth of granulation tissue. In granulomatous colitis, early changes include discrete, superficial ulcers, often against a background of normal mucosa, seen best en face. All of these changes can be demonstrated by the double-contrast technique. The radiological and endoscopic findings were in agreement in 95% of the examinations in the authors' series. The importance of the technical aspects of the examination is stressed.

Colitis, Ulcerative↗
PubMed1976

Hepatic infarction. A clinicopathologic study of seven cases.

Five of the seven cases of hepatic infarction that compose this study were encountered in a series of 442 consecutive autopsies, giving an incidence of one in 88 autopsies. The clinical and laboratory features were suggestive of hepatocellular dysfunction, although in only three cases was the diagnosis considered prior to death. Morphologically, in four of the seven patients, the infarcts were regarded as massive or of submassive proportions and were directly responsible for the patients' death. The majority of infarcts were of recent origin, with the estimated ages ranging from 18 to 72 hours. One was of about two weeks' duration and was the only example in this series associated with cirrhosis.

Adult↗
PubMed1976

The radiological differentiation between ulcerative and granulomatous colitis by double contrast radiology.

The purpose of this report is to illustrate the value of the double contrast technic for the detection of early changes of colitis and for the differentiation between ulcerative and granulomatous colitis. Fifty consecutive patients with radiologically-diagnosed nonspecific colitis are included and the radiographs, endoscopic and pathologic reports and photographs were reviewed. On radiological grounds ulcerative colitis were diagnosed in 23 patients and granulomatous colitis in 27 patients. There were no radiologically indeterminate cases. Follow-up information was obtained by colectomy in nine patients, colonoscopy in nine patients and sigmoidoscopy in the remainder. In no case did the endoscopic or pathologic diagnosis conflict with the radiological diagnosis. With the double contrast technic, very fine mucosal detail can be seen including features such as granular mucosa, "aphthoid" ulcers and discontinuous disease which are not demonstrable by the conventional single contrast barium enema. This detailed mapping of the nature and extent of disease facilitates the differential diagnosis between ulcerative and granulomatous colitis.

Colitis, Ulcerative↗
PubMed1975

Efficacy of hepatitis B immune serum globulin after accidental exposure. Preliminary report of the Veterans Administration Cooperative Study.

A randomised, double-blind, controlled trial has been undertaken to compare the efficacy of hepatitis B immune globulin (H.B.I.G.) with that of immune serum globulin (I.S.G.) for the prophylaxis of viral hepatitis. Participants in the trial were individuals exposed accidentally to material infectious for hepatitis (primarily viral B hepatitis). Preliminary evaluation of the first 302 of the 561 individuals entered into the study indicates that H.B.I.G. significantly reduced the frequencies of both clinical and subclinical hepatitis during the first 3--4 months after the injection. Less than 10% of H.B.I.G. recipients had detectable anti-HBs at the sixth month after the injection, suggesting that H.B.I.G. might need to be given every 3--4 months to continually exposed individuals. Further long-term evaluation is required in order to define more clearly those most likely to benefit from H.B.I.G.

Clinical Trials as Topic↗
PubMed1975

Reproductive performance of male and female phenotypes in three sex chromosomal genotypes(XX, XY, YY) in the killifish, Oryzias latipes.

The present study investigates the juvenile and adult reproductive performance of Japanese killifish, Oryzias latipes, which were successfully sex-reversed by feeding them male or female sex hormones during the fry stage. Sexual maturation of these laboratory grown fish of three known genotypes (XX, SY, YY) occurred earliest in untreated genotypes, next in genotypes treated with male hormone (methyl testosterone) and female hormone (estrone), respectively. The delay in sexual maturation caused by early exogenous, sex-hormone treatment may represent a disturbance in the delicate neural-gonadal axis. However, the degree of response was also strongly influenced by the animal's sex chromosomal genotype. XX fish, normally phenotypic females, were affected more by the male hormone than by the female hormone. XY and YY fish, normally phenotypic males, were delayed more by the female hormone than by the male hormone. This specific sex hormone-sex genotype interaction also influenced adult reproductive performance (sperm or egg production). Differences in the metabolism of male and female sex hormones by the XX, XY, and YY fish are probably responsible for these interesting findings.

Age Factors↗
PubMed1975

The diagnostic accuracy of barium studies of the stomach and duodenum--correlation with endoscopy.

Radiologic and endoscopic diagnoses were compared in 240 patients. In 175 patients examined by a standard barium contrast technique there were 39 radiological errors (22%). The most common causes of error were failure to detect an abnormality on the radiograph and prominent mucosal folds which could either mask or simulate small lesions. In 65 patients examined by a formal double contrast technique using effervescent pills and a thick barium suspension, there were 4 radiological errors (6%). In addition, superficial gastric erosions were demonstrated in 7 patients. Double contrast radiography appears to offer the potential for significant improvements in diagnostic accuracy.

Barium Sulfate↗
PubMed1975

Demonstration of superficial gastric erosions by double contrast radiography.

Superficial gastric erosions were found in 30 of 267 patients undergoing esophagogastroduodenoscopy. In 13 of these patients, and in 7 others not submitted to endoscopy, superficial gastric erosions were demonstrated radiologically by the double contrast technique. These may appear as flat, linear streaks, as dots of barium, or as target-like lesions with a central fleck of barium surrounded by a radiolucent halo. In 1 patient, a ring-shaped density was demonstrated due to a small blood clot adherent to a gastric erosion. Although patients presenting with acute hemorrhagic gastritis should still be examined first by endoscopy, double contrast radiography has been of value in patients presenting after the cessation of bleeding and in patients with vague digestive complaints. Because of our experience with the diagnosis of standard methods, and because of the Japanese experience with diagnosis of superficial gastric carcinoma, it is recommended that this technique be applied more widely to facilitate the detection of early and small lesions in the stomach.

Barium Sulfate↗
PubMed1973

Successful treatment of Pseudomonas cepacia endocarditis with trimethoprim-sulfamethoxazole.

A patient with a history of alcoholism and drug abuse who developed Pseudomonas cepacia endocarditis is described. The organism was found to be resistant in vitro to all common antimicrobial agents except chloramphenicol and trimethoprim-sulfamethoxazole. Treatment failed with penicillin and streptomycin and later with chloramphenicol. Orally administered trimethoprim-sulfamethoxazole, however, resulted in sterilization of the patient's blood and aortic valve which was resected 27 days after the start of therapy. A 6-week course of therapy was completed and, to date (6 months after treatment), there has been no recurrence.

Administration, Oral↗