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Biomedical subjects

R Stanton

Publications and source records attributed to R Stanton.

31 records · Page 2Linked to original sources
PubMed1986

Estrogen receptor protein in bone and soft tissue tumors.

Thirty-three histologically diverse bone and soft tissue tumors were analyzed biochemically for the presence of estrogen receptor protein (ERP) and progesterone receptor by means of a conventional, commercially available, steroid-binding assay (dextran-coated charcoal method) on fresh frozen tissue. These results were compared with analysis of ERP by using a specific monoclonal antibody both in an enzyme immunoassay and on frozen tissue sections by using immunohistochemical procedures. Frozen tissue sections were also examined for the presence of estrogen and progesterone receptors using fluorescein-labeled steroids. Six of the 33 tumors (18%) contained low levels of ERP ranging from 19 to 73 fmol/mg as determined by the dextran-coated charcoal method. The remaining 27 cases contained no (less than 10 fmol/mg) ERP. The ERP-positive group included a fibromatosis, leiomyosarcoma, liposarcoma (2 cases), neural sarcoma, and a synovial sarcoma. Four were high grades sarcomas, and two were low grade sarcomas. There was excellent agreement between the ERP levels determined by the dextran coated charcoal method and those determined by enzyme immunoassay. ERP could not be demonstrated immunohistochemically on frozen tissue sections of the tumors even though it could be demonstrated in breast carcinomas serving as positive controls. The failure of the immunohistochemical technique may be related to the low levels of ERP in these tumors and the difficulty of detecting antigen at threshold levels. Cytochemical localization of receptor protein employing fluoresceinated steroids did not correlate with cytosolic ERP as determined by enzyme immunoassay or the dextran coated charcoal method. Moreover, the high level of background fluorescence gave rise to a significant amount of intraobserver and interobserver variation. Although the clinical significance of ERP protein in mesenchymal tumors is still uncertain, the present findings, coupled with various clinical observations suggesting hormonal dependency of some mesenchymal tumors, indicate that investigation of a larger group of patients amenable to statistical analysis is warranted.

Adolescent↗
PubMed1984

Histiocytoid cardiomyopathy of infancy: deficiency of reducible cytochrome b in heart mitochondria.

A 3-week-old girl with failure to thrive and cardiomegaly died of cardiac arrest at age 4 weeks. Morphologic studies of the heart showed enlarged muscle fibers with large accumulations of mitochondria, characteristic of histiocytoid cardiomyopathy. Biochemical studies showed markedly decreased succinate-cytochrome c reductase and rotenone-sensitive NADH-cytochrome c reductase activities, while other mitochondrial enzymes were normal. In isolated mitochondria, cytochrome spectra showed a severe defect of reducible cytochrome b and a less marked defect of cytochrome cc1, while the content of cytochrome aa3 (cytochrome c oxidase) was normal. Histiocytoid cardiomyopathy appears to be due to a defect of complex III (reduced coenzyme Q-cytochrome c reductase) in the respiratory chain of heart mitochondria.

Cardiomyopathies↗
PubMed1983

Dose reduction through variable dose CT scanning: optimality of the filtered backprojection algorithm.

A novel approach to patient radiation dose reduction in X-ray computed tomography (CT) (variable dose scanning) is proposed and evaluated. This technique spares radiosensitive tissues from unnecessary radiation if they are not in the area of immediate clinical interest. Specifically evaluated is the potential for reduction of dose to the eye and active bone marrow in head transmission CT. Using computer simulations, doses are calculated for an easily implementable two level exposure variation, and results are discussed for the fully optimized case in which the intensities of all pencil beams are independently variable. Dose reductions of more than 80% in peak dose are possible in head scanning. To determine whether the filtered backprojection algorithm is optimal in terms of signal-to-noise ratio of the final images for this novel scanning technique, a Cramer-Rao lower bound to noise in the image (which is independent of reconstruction algorithm) is derived and calculated for several types of scan. The bound uses the photon distributions determined from mathematical optimization and is compared with the actual noise of the reconstructions. The comparison indicates that little if any improvement can be expected in signal-to-noise ratio using reconstruction algorithms other than the filtered backprojection.

Radiation Dosage↗
PubMed1976

Childhood polymyositis with cardiac conduction defects.

Pediatric polymyositis may be an entity distinct from dermatomyositis. Chronic polymyositis can occur in childhood and, as in adults, may be associated with arrhythmias. Microscopical involvement of the myocardium and pericardium in dermatomyositis is probably far more common than suspected on clinical grounds. Cardiac evaluation is suggested for all children with dermatomyositis or polymyositis, particularly prior to surgical procedures. Intracardiac electrographic recording techniques offer improved accuracy in determining the site of cardiac conduction defects, and may aid in planning for the use of antiarrhythmia medications or a pacemaker. In children with dermatomyositis or polymyositis known cardiac stimulants should be administered with care.

Arrhythmias, Cardiac↗
PubMedDate not supplied

The effectiveness of popular, non-prescription weight loss supplements.

OBJECTIVES: To review the evidence for the effectiveness of popular, non-prescription weight loss supplements. DATA SOURCES: A detailed literature search including all relevant medical and supplementary medicine databases and evidence submitted from manufacturers. DATA SYNTHESIS: The theoretical basis and rationale for the use of each substance is considered along with available research in the published literature on effectiveness and potential risks. We classified the level of evidence represented by the main research studies on each substance. CONCLUSIONS: There is no good evidence for any weight loss benefits from most of the substances reviewed here. There is some support for mild effects of capsaicin, caffeine and fibre, but only in whole foods. In some cases (e.g., chitosan), there is a plausible theoretical basis for the product, but no supporting proof of effect in humans in the absence of a calorie-controlled diet. Possible synergistic effects of different ingredients cannot be dismissed, but cannot be assessed from current data. There is an absence of good quality research on many substances, which means that advertising claims may be misleading.

Anti-Obesity Agents↗