Search PubMed⌕ Search

Biomedical subjects

J Scheer

Publications and source records attributed to J Scheer.

At least 19 recordsLinked to original sources
PubMed2004

An improved assay for enumeration of circulating endothelial cells.

Circulating endothelial cells have been established as markers of vascular disease, such as small vessel vasculitis, acute vascular rejection in renal transplant recipients, and cyclosporine-induced endothelial damage. Enumeration of these cells by immunomagnetic isolation and acridine staining remains the gold standard but necessitates considerable experience and expenditure. A simpler test would therefore be of great utility. Hence, our aim was to develop an improved simple assay to enumerate endothelial cells in peripheral blood. We had already used various surface markers to corroborate the endothelial origin of cells. Here, we studied the enumeration of cell numbers with immunomagnetic isolation and a variety of subsequent stains, such as CD31, von Willebrand's factor (vWF) immunocytochemistry, and Ulex europaeus lectin-1 (UEA-1). Eventually, we devised a simple protocol for enumeration using immunomagnetic isolation and a subsequent UEA-1 lectin stain. We evaluated the use of this protocol in parallel to immunomagnetic isolation and acridine counting alone in 92 renal transplant recipients who underwent renal biopsy. Recovery of various concentrations of human umbilical vein endothelial cells from blood was also studied. Immunomagnetic isolation and subsequent UEA-1 staining permits easier enumeration of circulating endothelial cells in peripheral blood. The assay is simple and easy to use, thus allowing for a more widespread use of circulating endothelial cells as a marker of vascular damage.

Blood Cell Count↗
PubMed2000

Suramin inhibits initiation of defense signaling by systemin, chitosan, and a beta-glucan elicitor in suspension-cultured Lycopersicon peruvianum cells.

Systemin-mediated defense signaling in tomato (Lycopersicon esculentum) plants is analogous to the cytokine-mediated inflammatory response in animals. Herein, we report that the initiation of defense signaling in suspension-cultured cells of Lycopersicon peruvianum by the peptide systemin, as well as by chitosan and beta-glucan elicitor from Phytophtora megasperma, is inhibited by the polysulfonated naphtylurea compound suramin, a known inhibitor of cytokine and growth factor receptor interactions in animal cells. Using a radioreceptor assay, we show that suramin interfered with the binding of the systemin analog (125)I-Tyr-2, Ala-15-systemin to the systemin receptor with an IC(50) of 160 microM. Additionally, labeling of the systemin receptor with a photoaffinity analog of systemin was inhibited in the presence of suramin. Receptor-mediated tyrosine phosphorylation of a 48-kDa mitogen-activated protein kinase and alkalinization of the medium of suspension-cultured cells in response to systemin and carbohydrate elicitors were also inhibited by suramin. The inhibition of medium alkalinization by suramin was reversible in the presence of high concentrations of systemin and carbohydrate elicitors. Calyculin A and erythrosin B, intracellular inhibitors of phosphatases and plasma membrane proton ATPases, respectively, both induce medium alkalinization, but neither response was inhibited by suramin. The polysulfonated compound heparin did not inhibit systemin-induced medium alkalinization. NF 007, a suramin derivative, induced medium alkalinization, indicating that neither NF 007 nor heparin interact with elicitor receptors like suramin. The data indicate that cell-surface receptors in plants show some common structural features with animal cytokine and growth factor receptors that can interact with suramin to interfere with ligand binding.

Chitin↗
PubMed1995

Murphy's contributions to disability studies: an inquiry into ourselves.

Robert Murphy's career, culminating in the study of disability, gives evidence of deep commitment to understanding the human condition in adversity. His life-long interest in the psychological, sociological and cultural significance of behavior; his work on alienation, developed through fieldwork in small scale societies in South America and Africa; his fascination with the estrangement that arises from the conflict between our need to integrate and to be autonomous; and his own experience of a progressive debilitating disease provided him with rich insights for his interpretation of disability. This paper examines Murphy's contributions to our understanding of the meanings and implications of disability, for those who personally experience it, and for the 'others' in their lives.

Anthropology, Cultural↗
PubMed1994

Do fish oils prevent restenosis after coronary angioplasty?

BACKGROUND: The omega-3 polyunsaturated fatty acids derived from fish oils have been shown to modulate many factors believed to affect the pathogenesis of atherosclerosis. Because certain features of restenosis following angioplasty mimic some of the early changes of atherogenesis, some researchers have suggested that fish oil might prevent restenosis following angioplasty. We report the effects of omega-3 fatty acids on the rate of restenosis following percutaneous intraluminal coronary angioplasty (PTCA). METHODS AND RESULTS: From August 1989 through September 1992, 551 patients were randomized to start receiving a daily dietary supplement of ten 1.0-g capsules containing 80.6% ethyl esters of omega-3 fatty acids providing 4.1 g eicosapentaenoic acid (EPA) and 2.8 g docosahexaenoic acid (DHA) for 6 months or an equal amount of an ethyl ester of corn oil. Four hundred seventy subjects who were well matched for risk factors completed successful angioplasty of one or multiple lesions in native coronary vessels and constituted the study cohort, of whom 447 were evaluable at 6 months after PTCA. The criteria for restenosis were that the quantitative coronary angiography at 6 months show a > 30% increase in narrowing at the stenosis site or loss of at least half of the gain achieved at the time of PTCA and final restenosis with < 50% luminal diameter remaining. In 93% of the patients, the end point was determined by angiography and in all except 1% of these by quantitative coronary angiography. Compliance with the fish oil supplement was good as judged by incorporation of EPA and DHA in plasma and red blood cell phospholipids. The restenosis rate among analyzable patients was 46% for corn oil and 52% for fish oil (P = .37). The addition of 200 mg alpha-tocopherol for all subjects during the study had no effect on restenosis rates. CONCLUSIONS: This was the largest of such trials to date, and a supplement of 8 g/d of omega-3 fatty acids failed to prevent the usual high rate of restenosis after PTCA. No adverse effects were attributable to this large daily supplement of omega-3 fatty acids.

Adult↗
PubMed1991

Exploratory mapping of evoked neuromagnetic activity from human peripheral nerve, brachial plexus and spinal cord.

Upon conventional median nerve stimulation at the wrist early magnetic fields were recorded using a SQUID magnetometer. At the upper arm, mono- and biphasic compound nerve action fields were detected, depending on the subject's distribution of single fiber conduction velocities. At the upper thorax, brachial plexus fields reversed polarity at the level of Erb's point; their distribution was asymmetric, probably due to volume currents. At the upper lateral neck, fields from proximal plexus, spinal cord (P13m) and the primary somatosensory cortex contralateral to the sensor position were detected. The observed P13m field distribution agrees with the electrophysiological concept of a sagittal segmental dorsal horn generator.

Brachial Plexus↗
PubMed1991

The treatment of uraemic hyperphosphataemia with calcium acetate and calcium carbonate: a comparative study.

A comparative study of long-term haemodialysis patients investigated the effects of calcium acetate and calcium carbonate on concentrations of serum phosphate, calcium, and parathyroid hormone. It was demonstrated that both substances led to a significant decrease in phosphate and serum parathyroid hormone. Administration of calcium acetate reduced the serum phosphate concentration in 7 weeks from an initial value of 2.08 +/- 0.53 mmol/l to 1.51 +/- 0.39 mmol/l (P less than 0.01). Following a 1-week wash-out period, calcium carbonate reduced the serum phosphate concentration in the same patients from 1.99 +/- 0.62 mmol/l to 1.34 +/- 0.40 mmol/l (P less than 0.01). Of particular significance, however, is the fact that in relation to daily elementary calcium intake, calcium acetate was a considerably more effective binder of intestinal phosphate than calcium carbonate. During administration of calcium acetate only 1.02 g of elementary calcium were required daily in order to reduce the serum phosphate concentration. The same patients, however, required 1.88 g of elementary calcium during calcium carbonate therapy. Complementary studies investigated the influence of an accompanying calcitriol medication. In this instance, too, calcium acetate was shown to be more effective; although the patients developed hypercalcaemia with calcium acetate, this happened more often with calcium carbonate. In summary it can be said that daily calcium loading of the uraemic organism under calcium acetate therapy is reduced by nearly half as compared to calcium carbonate therapy, and that this can be achieved with the same effective decrease of the serum phosphate concentration.

Acetates↗
PubMed1991

The cultural context of polio biographies.

Cultural contexts influence the ways individuals interpret and experience functional losses associated with post-polio sequelae. Using in-depth multiple interview case studies from two National Institute on Aging projects, the concept of "biographies" is presented to place the individuals' polio-related experiences within the context of their lives. Two major cultural contexts shape the construction of polio biographies: normative life course expectations and developmental tasks; and traditions associated with polio recovery and rehabilitation. The authors identify key dimensions of personal concern among polio survivors that can be used as entrance points for effective clinical intervention and to promote treatment compliance.

Activities of Daily Living↗
PubMed1989

Early infant mortality in West Germany before and after Chernobyl.

Early infant mortality rates in West Germany were plotted for regions with different radioactive burdens following the Chernobyl nuclear reactor explosion in April, 1986. In all regions, the logarithms of the mortality rates fitted a linear model between 1975 and 1985, but from May, 1986, immediately after the accident, there was a striking deviation from the model in areas with greatest radioactive fallout.

Accidents↗