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Biomedical subjects

W Sheldon

Publications and source records attributed to W Sheldon.

At least 19 recordsLinked to original sources
PubMed2000

Ad hoc coronary intervention.

Ad hoc coronary intervention is a percutaneous revascularization procedure performed at the same sitting as diagnostic cardiac catheterization. While this appears to be an efficient strategy, the safety and cost of ad hoc coronary intervention compared with delayed coronary intervention have not been clearly documented. Special preparation and precautions are necessary for patients in whom ad hoc coronary intervention is anticipated. Ad hoc coronary intervention is not appropriate if informed consent has not been previously obtained or if it would pose greater risks than delayed intervention. While ad hoc coronary intervention is often efficient and effective, its use should be individualized. Cathet. Cardiovasc. Intervent. 49:130-134, 2000.

Cardiac Catheterization↗
PubMed1999

Lessons learned from the review of cardiac catheterization laboratories: a report from the Laboratory Survey Committee of the Society for Cardiac Angiography and Interventions.

The Laboratory Survey Committee of the Society for Cardiac Angiography and Interventions was created as a resource for physicians and administrators to provide comprehensive independent outside review services for cardiac catheterization laboratories. Since 1989, when the committee began its work, surveys of 23 catheterization laboratories have been completed. Our review of this experience identified several recurring problems among the laboratories. The purpose of this paper is to summarize our experience and highlight the lessons we learned in the hope that this information will benefit many other laboratories.

Cardiac Catheterization↗
PubMed1996

Immunohistochemical and morphological characterization of spontaneously occurring pheochromocytomas in the aging mouse.

Pheochromocytomas in mice are rare tumors, and their expression of functional markers has not previously been assessed. In this study, 29 spontaneously occurring mouse pheochromocytomas were characterized morphologically and immunohistochemically to determine whether there are functional correlates to previously described morphological features and to provide a database for comparison with tumors that arise in genetically engineered animals. The tumors were derived from 28 mice 828-1,489 days old, of three genotypes. Considerable cytological and architectural polymorphism was observed both within and between tumors. Most of the tumor cells were comparable in size to normal chromaffin cells or were larger. Small basophilic cells, which are the predominant cell type in rat pheochromocytomas, were usually in the minority. All of the tumors and most of the cells within individual tumors expressed immunoreactive tyrosine hydroxylase (TH). The tumors were variably positive for phenylethanolamine-N-methyltransferase (PNMT) and chromogranin A (CGA). There did not appear to be a global association of specific cytological features with expression of TH, PNMT, or CGA, although cells of similar appearance often shared similar immunoreactivities within individual tumors. Small basophilic cells could be either PNMT-positive or PNMT-negative. The frequency, morphology, and immunophenotype of mouse pheochromocytomas suggest that the mouse may be more appropriate than the rat as a model for human adrenal medullary pathology. In addition, the expression of immunoreactive PNMT by mouse pheochromocytomas suggests that these tumors are a potential source of epinephrine-producing cell lines, for which adequate models currently do not exist.

Adrenal Gland Neoplasms↗
PubMed1995

Chronic study of triprolidine for oncogenicity in mice.

Triprolidine hydrochloride was fed to groups of 60 B6C3F1 mice per sex at dietary levels of 0, 500, 2000, or 4000 ppm (as the free base) for up to 2 years. Up to 12 mice of each sex and dose group were terminated after 65 weeks for hematology and clinical chemistry. The control and high-dose groups were examined histologically. A complete histopathological examination was performed on the remaining 48 mice from each dose group when removed from study due to moribund condition, early death, or terminal euthanization at 105 weeks. Triprolidine did not significantly alter the survival of either sex. High-dose male and mid- and high-dose female body weights were significantly less than controls at the end of the study. Significant trends toward lower frequency with increasing dose were noted in females for fatty change in the liver and lymphomas (combination of lymphocytic, mixed, and histiocytic lymphomas). Similar negative trends in males were for lymphocytic cellular infiltration in multiple organs and lung alveolar/bronchiolar adenomas or the combination of alveolar/bronchiolar adenomas or carcinomas. Significant trends toward increased frequency with increasing dose were found in female mice for lymphocytic infiltration in multiple organs and cytoplasmic alterations of the acinar cells of the parotid gland. Similar positive trends were found in males for cytoplasmic alterations of the parotid gland and various hepatocellular changes (e.g., hypertrophy and altered foci). While there was a positive dose response trend for hepatocellular adenomas in males the combination of these and hepatocellular carcinomas eliminated the significant trend, and it was concluded that there was no evidence of a carcinogenic response to triprolidine in B6C3F1 mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Triprolidine: 104-week feeding study in rats.

The antihistamine triprolidine hydrochloride, was fed at dietary concentrations of 0, 250, 1000, or 2000 ppm (as the free base) to groups of 60 Fischer 344 (F344) rats of each sex for up to 2 years to evaluate its potential carcinogenicity. Up to 12 per sex from each group were killed at 65 weeks, and hematology, clinical chemistry, and histopathology were evaluated. A complete histopathological evaluation was performed on all other animals; survivors were killed at 2 years. Survival was significantly extended in triprolidine-treated males and females, particularly at the high dose. At the close of the study high-dose males and females had gained significantly less body weight than controls. Among rats killed at 65 weeks females in the mid- and high-dose groups weighed significantly less than controls, but weights of control and dosed males were not significantly different. The incidences of numerous lesions tended to decrease with increasing triprolidine dose. In females, clitoral gland adenomas, thyroid c-cell hyperplasia and neoplasia, mammary gland hyperplasia and fibroadenomas, and uterine stromal polyps, and in males, anterior pituitary gland adenomas, preputial gland neoplasia, thyroid c-cell pancreatic islet neoplasia, mononuclear cell leukemia, and the combination of lymphocytic, histiocytic, and undifferentiated cell malignant lymphomas and mononuclear leukemia, all exhibited negative dose trends. Cytoplasmic alterations of the parotid gland and numerous liver lesions tended to be more frequent in treated than in control animals. Liver lesions that exhibited positive dose trends include chronic inflammation and centrilobular fatty change in both sexes, mixed cell foci, and the combination of mixed cell foci and eosinophilic foci in females, and in males, basophilic foci and eosinophilic foci. Triprolidine was not carcinogenic in F344 rats.

Animals↗
PubMed1995

Major maxillofacial infections. An evaluation of 107 cases.

A review of 107 cases of acute maxillofacial infections managed at the Royal Melbourne Hospital was undertaken, and details of the presentations, demography, management, and outcomes of these patients are presented. The results indicated that many of the patients had sought treatment from dentists in general practice, and that a significant proportion had received sub-optimal management prior to referral. Thus a review of the principles of management and guidelines for the referral of patients with maxillofacial infections is also presented.

Adolescent↗
PubMed1993

Expression of mononuclear phagocyte antigens in histiocytic sarcoma of mice.

Twenty cases of histiocytic sarcoma in 15 female and five male (384 to 722 days of age) hybrid F1 (C57BL/6 x BALB/c) or F2 (F1 x F1) mice were studied for expression of mononuclear phagocyte and other antigens. Histiocytic sarcomas were found most often in liver, uterus, spleen, and lung. Tissues fixed in Bouin's fluid provided preservation of antigen immunoreactivity, using avidin biotin peroxidase complex immunohistochemistry, with monoclonal and polyclonal antibodies. The mononuclear phagocyte antigens, lysozyme and Mac-2 (a galactose-specific lectin that binds IgE), were found in 60-70% of the cases. The receptor for the macrophage colony-stimulating factor (CSF-1), c-fms, was expressed in 2/20 (10%) of the cases. Mouse immunoglobulins were not found in histiocytic sarcoma cells. In uterine histiocytic sarcomas, previously reported as Schwannomas because of their histologic appearance, S-100 protein was not expressed by tumor cells, although they usually expressed Mac-2 and lysozyme. Hyaline droplets were found in the renal tubules of only 2/19 cases. Our studies provide evidence that murine histiocytic sarcoma expresses antigens (Mac-2, lysozyme, c-fms) found in cells of the mononuclear phagocyte series, in contrast to the B-cell origin of many human histiocytic tumors.

Animals↗
PubMed1990

Estrogen-induced thyroid follicular cell adenomas in C57BL/6 mice.

Diethylstilbestrol (DES) was fed chronically to C57BL/6 mice at concentrations of 0, 5, 10, 20, 40, 160, 320, or 640 ppb in order to define the dose-response curve for neoplastic responses. The incidence of thyroid follicular cell adenomas was higher in control females than in males and was increased at mid-level doses of DES, especially in males. None were found in mice fed 640 ppb DES, probably because these mice died from other causes before follicular cell adenomas had developed. In both sexes, DES fed at 160 or 320 ppb significantly shortened time-to-onset of these tumors, and 40 ppb increased their probability late in life. It is concluded that DES has a causal relationship to thyroid neoplasia in C57BL/6 mice, and similarities between this and the human disease suggest that C57BL/6 mice may be an appropriate model for human thyroid neoplasia.

Adenoma↗
PubMed1989

Carcinogenicity study of 3,3'-dimethylbenzidine dihydrochloride in BALB/c mice.

BALB/c mice (120/sex/dose) were given 0, 5, 9, 18, 35, 70 or 140 ppm of 3,3'-dimethylbenzidine dihydrochloride in their drinking-water and killed after 13, 26, 39, 52, 78 or 116 wk. Full histopathological evaluations were performed on all animals that were found dead or moribund, or that were killed on schedule. Fatal lung alveolar cell neoplasms began to appear in males receiving 140 ppm at 78 wk and there was a significant dose-related decrease in the time-to-death from this cause. There were no significant dose-related trends for this neoplasm in females, nor were there treatment-related effects on body weight, water consumption or other lesions in either sex. This is the first report of a neoplastic response to 3,3'-dimethylbenzidine dihydrochloride in mice.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1989

Active and passive sugar absorption in pancreatic insufficiency.

Urinary excretion of lactulose, mannitol, and 3-0-methylglucose, following oral administration (5 g, 5 g, and 2 g, respectively, in 100 ml H2O; 80 ml/m2), has been measured in subjects with cystic fibrosis (CF) (22), Shwachman syndrome (3), chronic pancreatitis (3), and normal controls (46). Mean lactulose excretion was increased 10-fold in CF (p less than 0.001), and two-fold in other disorders associated with pancreatic insufficiency (PI) (p less than 0.05). Mean mannitol excretion was 1.6 times greater in CF (p less than 0.001), compared with controls, but was reduced in other forms of PI (p less than 0.03). The mean lactulose/mannitol excretion ratio was increased in all types of PI (p less than 0.001). There were no significant differences in 3-0-methylglucose excretion. This study confirms the large increase in lactulose absorption recently reported in CF and also demonstrates increased absorption of mannitol; these changes are different than those in other forms of PI. This study provides further evidence for a specific abnormality of the mucosal barrier to the absorption of passively absorbed, water soluble molecules in CF.

3-O-Methylglucose↗
PubMed1984

Simplified urinary oxalate determination using an enzyme electrode.

An enzyme electrode for urine oxalate measurement has been produced using acrylamide gel-entrapped oxalate decarboxylase retained over a CO2 sensor. Urine required pre-treatment with EDTA, but oxalate extraction was not necessary and inhibition by phosphate and sulphate was not apparent until after 10-14 days. The linear range was 0-0.2 mmol/l. Analysis of 50 urine specimens diluted 1 in 10 in pH 3.0 glycine buffer showed good correlation with a widely-used colorimetric method (y = 1.101x-0.018, r = 0.955).

Adult↗
PubMed1984

Lack of effect of tryptophan treatment in demented gerontopsychiatric patients. A double-blind, crossover-controlled study.

Twenty-eight elderly patients with dementia and in many cases also depression received daily treatment with either L-tryptophan (3g in the evening) or casein (control substance) for 1 month each, using a crossover design and double-blind procedures. Each patient's mental condition and performance ability were rated, and biological variables (serum tryptophan levels, platelet 5-HT uptake, platelet MAO activity, red blood cell thiamine, pyridoxine and riboflavin levels) were measured. Serum tryptophan levels were elevated by tryptophan treatment, but the treatment failed to have significant effects on the mental condition of the patients as a whole. Dividing the patients into two groups on the basis of the treatment during which they received their best behavioral rating failed to show significant relations to biological variables, except for differences between Vmax values for platelet 5-HT uptake. The findings indicate that long-term administration of tryptophan to gerontopsychiatric patients does not generally have beneficial effects.

Aged↗
PubMed1983

Relationship of mouse body weight and food consumption/wastage to cage shelf level.

The relationships between the shelf level at which mice were housed and body weight and food consumption/wastage were examined by analyzing data obtained from the first 9 months of a carcinogenic dose-response study carried out in 24,192 female BALB/c mice using 2-acetylaminofluorene (2-AAF) as the carcinogen. Each cage, containing four mice, was maintained on a rack at a given shelf level throughout the course of the experiment to allow analysis of data by shelf level. The amount of food removed from each feeder and the body weight of each mouse was measured weekly. Average body weight gain during the first 12 weeks was lowest on the top shelf, highest on the next two shelves, and progressively lower as the shelf approached the lowest level on the rack. Body weights attained by week 36 of the experiment generally reflected this same pattern. Weekly food consumption/wastage, as measured by disappearance of food from the feeder, generally showed the converse shelf-level pattern as that shown by body weight gain. Removal of food from feeders was greatest on the top shelf, lowest on the next shelf, and progressively increased with each succeedingly lower shelf. Although it is not clear whether the food removal pattern was related more to food consumption or food wastage, the observation was reproducible.

2-Acetylaminofluorene↗
PubMed1982

Influence of cage shelf level on retinal atrophy in mice.

The correlation between cage shelf level and retinal atrophy was examined by analyzing data obtained from a chronic study carried out in 24,192 female BALB/c mice. Each cage of animals was maintained on a cage rack at a given shelf level throughout the course of the experiment, thus allowing analysis of data by shelf level. Retinal atrophy was first observed in a mouse killed at 12 months but subsequently was observed only at and after 16 months. This lesion was confined largely to animals on the top shelf. At 24 months, 19.7% of the mice on the top shelf had retinal atrophy while 0.2% of animals on all other shelves had the lesion. By 33 months, retinal atrophy was present in 30.2% of the mice on the top shelf, 12.0% on the next shelf, and 0.7% on the lower shelves. Differences in retinal morphology were probably caused by differences in lighting intensity. It was concluded that cage shelf level should be considered as an important factor in any chronic studies with mice.

Animals↗
PubMed1969

Prognosis in early adult life of coeliac children treated with a gluten-free diet.

Long-term follow up of 57 young adults with coeliac disease diagnosed in childhood showed that 13 had relapsed clinically and had resumed a gluten-free diet Of the remainder, who were taking a normal diet and were apparently normal, 19 had low serum folate levels and 11 low serum iron levels. Pregnancy was found particularly likely to provoke an overt relapse.Only six patients were found to be stunted in height, while the menarche had occurred within the average range. The study also confirmed the very low present-daymortality rate of coeliac disease in childhood, which at the Hospital for Sick Children in London has been 0.4% between 1951 and 1968. In view of the finding that childhood coeliac disease usually persists, even though not causing symptoms, it is suggested that the use of a gluten-free diet should be lifelong.

Adolescent↗