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Biomedical subjects

J Baron

Publications and source records attributed to J Baron.

At least 163 records · Page 9Linked to original sources
PubMed1988

Measuring the economic impact of perioperative total parenteral nutrition: principles and design.

Although the use of total parenteral nutrition (TPN) has been increasing in recent years, few studies have been performed on both its costs and its effectiveness or benefits. This paper provides a general review of the methods of cost-effectiveness and cost-benefit analysis, summarizes briefly the existing cost-analysis studies of TPN, and outlines the authors' proposed study design for their economic assessment of TPN.

Clinical Trials as Topic↗
PubMed1988

Immunohistochemical demonstration of isozyme- and strain-specific differences in the intralobular localizations and distributions of UDP-glucuronosyltransferases in livers of untreated rats.

Antibodies directed against three isozymes of rat hepatic microsomal UDP-glucuronosyltransferase (EC 2.4.1.17), p-nitrophenol, 3 alpha-hydroxysteroid, and 17 beta-hydroxysteroid UDP-glucuronosyltransferases were used to localize these enzymes at the light microscopic level in livers of untreated Sprague-Dawley and Wistar rats. Avidin-biotin-peroxidase staining revealed the presence of each isozyme within parenchymal cells throughout the liver lobule in rats of both strains. However, although antibodies to the 3 alpha- and 17 beta-hydroxysteroid UDP-glucuronosyltransferases appeared to stain hepatocytes across the liver lobule quite uniformly, centrilobular hepatocytes were stained much more intensely for p-nitrophenol UDP-glucuronosyltransferase than were midzonal and periportal cells. Additionally, appreciable immunohistochemical staining for p-nitrophenol UDP-glucuronosyltransferase, but not for the two hydroxysteroid UDP-glucuronosyltransferases, was detected within the epithelium of the hepatic bile duct and the endothelium of the hepatic artery and portal vein. Another difference was noted in livers of Wistar rats: hepatocytes of rats possessing low 3 alpha-hydroxysteroid (i.e., androsterone) UDP-glucuronosyltransferase activity were stained much less intensely for the 3 alpha-hydroxysteroid UDP-glucuronosyltransferase than were those of rats exhibiting high rates of androsterone glucuronidation, whereas differences in immunoperoxidase staining for p-nitrophenol and 17 beta-hydroxysteroid UDP-glucuronosyltransferases were not apparent between the two subclasses of Wistar rats. These immunohistochemical findings demonstrate that different UDP-glucuronosyltransferase isozymes are distributed across the liver lobule in significantly different manners and, furthermore, suggest that xenobiotics may be glucuronidated within epithelial cells of the hepatic bile duct and endothelial cells of the hepatic artery and portal vein, as well as within hepatocytes. The results of this study also provide evidence that differences in the content of 3 alpha-hydroxysteroid UDP-glucuronosyltransferase within hepatocytes account for genetically determined variations in the rates at which androsterone and certain other xenobiotics are glucuronidated in livers of Wistar rats.

Animals↗
PubMed1987

Microfluorometric determination of DNA adducts in immunofluorescent-stained liver tissue from rats fed 2-acetylaminofluorene.

The intensities of immunofluorescence in nuclei stained by an antiserum specific for the DNA adduct N-deoxyguanosin(8-yl)aminofluorene (dG-8-AF), were quantified by microfluorometry in frozen liver sections from male Fischer rats fed 2-acetylaminofluorene (AAF). Results of previous studies demonstrated that dG-8-AF is the predominant adduct (80-100%) formed in livers of rats fed AAF continuously, and that nuclei of hepatocytes and bile duct epithelial cells in rats fed AAF exhibit an adduct-specific immunofluorescence. In the present investigation, nuclear staining for dG-8-AF was quantified by microfluorometry in liver sections from male Fischer rats fed 0.02% AAF continuously for 2, 4, 8, 12, 16, 20, and 28 days. Microfluorometric determinations of the intensities of nuclear immunofluorescence staining within periportal, midzonal, and centrilobular hepatocytes and bile duct epithelial cells revealed that levels of the dG-8-AF adduct increased in these cells during AAF feeding, reaching a plateau by 12 days. However, significant differences were detected in dG-8-AF levels within cells of each lobular area. Nuclei of periportal hepatocytes exhibited the most intense immunofluorescence, nuclei of centrilobular hepatocytes and bile duct epithelial cells emitted the least intense fluorescence, and nuclei of midzonal hepatocytes exhibited an intermediate fluorescence intensity. Quantitation of whole-liver levels of the dG-8-AF adduct by RIA, after extraction of DNA, also revealed that adduct accumulation reached a plateau by 12 days of AAF feeding. Thus, similar profiles of adduct accumulation were obtained by microfluorometric analysis of immunofluorescence staining within frozen liver sections, and by RIA analysis of DNA extracted from whole livers. The periportal concentration of DNA adducts in livers of rats continuously fed a carcinogenic dose of AAF may be an important early event in AAF-induced liver tumorigenesis.

2-Acetylaminofluorene↗
PubMed1987

Phantom kidney--a pitfall in radionuclide study of urinary tract.

A survey was done on 39 nephrectomized patients who underwent our routine radionuclide kidney study including blood flow imaging at various periods postoperation. Perfusion of varying degree was demonstrated in the area of the nephrectomized kidney in 17 patients showing equal or less activity than the actual kidney. This so-called phantom kidney was reproducible in the same patient and was found four weeks to ten years after nephrectomy. Thirteen phantom kidneys were found on the left side and four on the right. Seven were after simple nephrectomy, four after radical nephrectomy, and six after nephroureterectomy. Besides being a source of error in interpretation in kidney imaging, the appearance of this residual postnephrectomy blood flow is difficult to explain, particularly in the cases of radical nephrectomy.

Adult↗
PubMed1987

[Tumors and tumor-like diseases of the carpal bones].

This presentation concerns the findings in 105 tumors or tumor-like lesions in the bones of the carpus. These tumors generally produce complaints which are uncharacteristic and they are quite difficult to recognize on X-ray. Due to this difficulty, there may be many different therapies before the correct final diagnosis is confirmed. These tumors are usually found in the scaphoid, capitate, lunate, or hamate. Of the 105 tumors, 45.7% were osteoid osteoma, which has an incidence of only 11.33% of all bone tumors in the body as a whole. Of the remaining tumors, 15.24% were diagnoses to be intraosseous ganglia (= tumorlike lesions). Lesser percentages were giant-cell tumors, osteochondromas, chondromas. One intraosseous lipoma was found and this had never before been reported. The majority of the patients were between twenty and thirty years of age. With surgical removal, complaints are generally reduced. Dramatic relief from pain is reported by patients when an osteoid osteoma is removed. The most important deduction from these findings is that tumors in the carpus are not as rare as once assumed. The possibility of bone tumors should be considered in patients with intractable pain in the carpus.

Bone Cysts↗
PubMed1986

Identification of intratissue sites for xenobiotic activation and detoxication.

Results of immunohistochemical and histochemical investigations on xenobiotic-metabolizing enzymes and aryl hydrocarbon hydroxylase activity have demonstrated that xenobiotic activation and detoxication do not occur uniformly throughout the liver, skin, respiratory tract, and pancreas, four tissues that are targets for the toxic actions of xenobiotics that are biotransformed into reactive metabolites. It has been shown that there can be significant differences in the levels and activities of xenobiotic-metabolizing enzymes among even morphologically similar cells, that an inducer can affect a specific xenobiotic-metabolizing enzyme to significantly different extents within different cells in a tissue, and that inducers of xenobiotic-metabolizing enzymes can alter differentially the extents to which different cells within a tissue participate in xenobiotic metabolism. These studies also have revealed that the route of administration of an inducer can affect significantly the induction of xenobiotic-metabolizing enzymes and aryl hydrocarbon hydroxylase activity within an organ such as the pancreas. Some of the immunohistochemical findings reported for the cellular localizations of xenobiotic-metabolizing enzymes within specific tissues, e.g., the nasal mucosa, may not appear to be entirely consistent with the intratissue distribution of benzo[a]pyrene hydroxylase activity, especially after induction. However, it must be appreciated that other cytochrome P-450 isozymes undoubtedly are present within these tissues which, although not studied, also are capable of catalyzing aryl hydrocarbon hydroxylase activity.

Animals↗
PubMed1986

Individual differences in syllogistic reasoning: deduction rules or mental models?

Two studies examined the correlates of reasoning ability on a syllogistic reasoning task in subjects who lacked formal background in logic. The main issue addressed was the extent to which reasoning proficiency arises from the consideration of multiple possible set relations (mental models) as opposed to explicit or implicit reliance on deduction rules. Evidence for the use of both models and rules was obtained. Although "good" and "poor" reasoners differed even when time constraints were imposed (consistent with the supposition of a better set of rules among good reasoners), good reasoners showed more improvement and chose to take longer amounts of time when time constraints were removed, suggesting that they considered more alternatives than did the poor reasoners. A comparison between these two groups and a third group of subjects, graduate students who had studied logic, reveals striking differences in both accuracy and speed.

Cognition↗
PubMed1986

Mycosis fungoides involving the central nervous system.

The clinical records of nine patients, followed at the University of Chicago, with mycosis fungoides (MF) and neurologic deficits due to direct CNS involvement were reviewed. Lymph node and visceral involvement was present in all patients. Clinical findings included cranial nerve deficits in four patients, altered mental status in eight, gait disturbances in three, and leg weakness in one. Helpful diagnostic studies included lumbar puncture with CSF cytology, computerized tomography (CT) brain scans, brain biopsy, and myelogram. Two patients, who were treated with radiation therapy (RT), survived 14 and 40 weeks, respectively. Survival of less than 4 weeks limited treatment in the other patients. Autopsies were performed on six patients and revealed meningeal infiltration and perivascular infiltration of the brain. In addition, the cerebral parenchyma was infiltrated in one patient and a lymphomatous tumor was found in the brainstem of another. We conclude that the varied clinical and pathologic features of CNS involvement with mycosis fungoides resemble those seen in leukemias and other lymphoproliferative disorders. Better awareness of the clinical features may permit earlier diagnosis and initiation of therapy.

Adult↗