Search PubMed⌕ Search

Biomedical subjects

S Bloom

Publications and source records attributed to S Bloom.

At least 37 records · Page 2Linked to original sources
PubMed1995

Adhesion molecules intercellular adhesion molecule-1 (ICAM-1), ICAM-3 and B7 are not expressed by epithelium in normal or inflamed colon.

Adhesion molecules are involved in facilitating cell-mediated immune events. Because lymphocyte-epithelial cell interaction has been implicated in the pathogenesis of colonic inflammation, we analysed expression of a range of adhesion molecules on colonic epithelium in vitro and in vivo using flow cytometry, immunohistochemistry and in situ hybridization. Expression of ICAM-1 by cell lines HT29 and int407 was increased by proinflammatory cytokines interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and IL-1 but not by IL-6. Vascular cell adhesion molecule (VCAM) and E-selectin were not expressed. Immunohistochemistry using sections of inflamed colon from 16 patients with ulcerative colitis (UC), five patients with Crohn's disease (CD) and seven patients with normal colonoscopic biopsies, showed no expression of ICAM-1 on colonic epithelium. VCAM was seen in isolated lymphoid aggregates and E-selectin was expressed on endothelium. In situ hybridization showed no ICAM-1 or ICAM-3 mRNA in colonic epithelium. B7, the ligand for CD28, was not found on normal or inflamed colonic epithelium. The adhesion molecules ICAM-1, ICAM-3 and B7 are not involved in lymphocyte-epithelial cell interaction in the normal or inflamed colon. This may have implications for the development of T cell tolerance to intestinal luminal antigens.

Antigen-Presenting Cells↗
PubMed1995

Adhesion molecule expression in primary sclerosing cholangitis and primary biliary cirrhosis.

There are conflicting reports regarding intercellular adhesion molecule-1 (ICAM-1) expression in primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC). Expression of adhesion molecules ICAM-1, lymphocyte adhesion molecule-1 (LFA-1), vascular cell adhesion molecule (VCAM), and E-selectin was examined together with HLA-DR in 16 liver biopsy specimens showing PSC and 12 specimens showing PBC. These were compared with biopsy specimens showing large duct obstruction (n = 7), chronic active hepatitis (n = 4), alcoholic liver disease (n = 4), and normal liver histological results (n = 5). ICAM-1 was detected on biliary epithelium in five of seven PSC specimens of histological stage 3 or 4, but not in nine early PSC specimens or in specimens from disease controls. In PBC, ICAM-1 was positive on three of 12 cases, two stage 2, and one stage 3. Nine of 16 PSC specimens (three of nine early, six of seven late disease) and six of 10 PBC specimens (three early, three late disease) were positive for HLA-DR. LFA-1 stained infiltrating inflammatory cells in PSC, PBC, and disease controls. In conclusion, ICAM-1 expression on biliary epithelium in PSC occurs mainly in late stage disease and therefore may be secondary to previous events inducing inflammation rather than of primary pathogenic importance. ICAM-1 expression in PBC is less common and not clearly associated with a particular disorder. Previous reports of ICAM-1 prevalence may have been biased towards end stage, pre-transplantation biopsy specimens.

Cell Adhesion Molecules↗
PubMed1995

Effect of peptide YY on human renal function.

Peptide YY (PYY) is released from the intestine into the circulation in response to ingestion of food. As PYY/neuropeptide Y (NPY) receptors have recently been identified in the human kidney, we examined the effect of PYY on human renal function. Male subjects (6 per group) received control infusate or PYY at 0.4 or 1.2 pmol.kg-1.min-1 intravenously for 90 min with control periods before and after. Infusion of PYY at the lower dose reproduced normal postprandial plasma concentrations and caused significant decreases in glomerular filtration rate (10% reduction), plasma renin activity (30% reduction), and aldosterone levels while increasing sodium excretion by approximately 30% (all P < 0.01). Infusion of PYY at the higher dose, which reproduced plasma levels seen during a diarrheal illness, resulted in similar changes in renal function and also reduced renal plasma flow by approximately 10% (P < 0.05). Therefore, PYY may be an important mediator of the normal postprandial natriuretic response, and PYY agonists could provide a novel approach to the treatment of patients with sodium overload.

Adult↗
PubMed1995

Adhesion molecule expression on vascular endothelium and nitroblue tetrazolium reducing activity in human colonic mucosa.

BACKGROUND: Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known about their functional activity in vascular endothelium. METHODS: We studied in situ nitroblue tetrazolium reducing activity and expression of E-selectin, ICAM-1, CD31, and VCAM-1 by immunohistochemistry in the same biopsy specimen in controls and patients with ulcerative colitis (UC). RESULTS: VCAM-1 expression was negative in mucosal vessels. E-selectin-positive vessels were significantly increased in endoscopically active colitis compared with normal mucosa. ICAM-1-positive vessels were consistently found in normal, quiescent UC and active UC. CD31-positive vessels were not significantly increased in quiescent UC and active UC compared with control. Only E-selectin significantly correlated with the histologic grade of inflammation. Nitroblue tetrazolium reducing vessels were increased in inflamed mucosa, and these vessels expressed ICAM-1 and CD31. E-selectin positivity in association with nitroblue tetrazolium reduction was mainly seen in the large mucosal vessels, but capillaries showing nitroblue tetrazolium reduction were rarely positive for E-selectin. CONCLUSIONS: Phenotypic and functional activation of vascular endothelium might be involved in the recruitment of leukocytes and tissue destruction of inflamed colonic mucosa.

Adult↗
PubMed1994

The prevalence of eating disorders in thyroid disease: a pilot study.

The aim of this study was to determine the prevalence of eating disorders and partial syndromes in women with thyroid disease. Female patients between the ages of 18 and 45 who attended a specialist thyroid clinic, in 1990, were asked to complete two self-report questionnaires (Bulimic Investigatory Test, Edinburgh, BITE and General Health Questionnaire, GHQ). High scoring patients were invited to attend for a research interview. The case notes of non-responders were examined. Seventy-three patients were entered into the study and 50 subjects returned their questionnaires (69%). Eleven patients scored highly on the BITE, nine of these patients also scoring highly on the GHQ, as did a further 12 patients. Ten patients were interviewed; of these, three patients (4%) met DSM111R criteria for bulimia nervosa and three patients met criteria for an eating disorder not otherwise specified. These results suggest that there is an increased prevalence of eating disorders in women thyroid patients.

Adolescent↗
PubMed1994

Inappropriate expression of blood group antigens in hepatic allografts.

We examined the expression of blood group antigens of the ABO, Lewis and Kell antigen systems using monoclonal antibodies and immunohistochemical study on 42 liver allograft specimens from 33 patients who underwent liver transplantation between 1986 and 1991 to learn whether altered blood group antigen expression might have a bearing on the immunopathogenesis of transplant rejection. Specimens were obtained at intervals of 0 days to 3 yr after transplant; they yielded the following histological diagnoses; time zero (n = 4), acute rejection (n = 4), pure cholestasis (n = 4), biliary obstruction (n = 4), early chronic rejection (n = 4), end-stage chronic rejection (n = 15) and miscellaneous late posttransplant biopsies (n = 7). Aberrant expression of blood group antigens was observed in 5 of 15 patients with chronic rejection. Two transplants into the same group O patient showed aberrant expression of AB antigens on hepatocytes, with a canalicular pattern, in group O-transplanted livers. In all three cases in which a group O liver was transplanted into a group A recipient and histological signs of chronic rejection were present, antibody staining showed acquisition of recipient blood phenotype by the donor liver bile ducts, endothelium or both. Aberrant expression of ABO antigens was seen only in chronic rejection. In seven cases we noted canalicular staining of periportal hepatocytes with the Lewis antibodies, normally confined to ducts and ductules. This was associated with severe cholestasis in six of the seven cases and may have represented early ductular metaplasia. These changes in carbohydrate cell surface phenotype may play a role in regulation of hepatic allograft susceptibility to immune-mediated damage.

Adolescent↗
PubMed1993

Trans-cellular desmin-lamin B intermediate filament network in cardiac myocytes.

Excessive stretch of heart muscle is thought to be a determinant of myocardial hypertrophy. Because cell shape and nuclear shape are closely coupled in cardiac myocytes, we hypothesize that excessive stretch causes physical deformation of the nucleus which might be responsible for some molecular events leading to hypertrophy. Cell shape and nuclear shape are most likely to be coupled by cytoskeletal elements. With this in mind, we have used immunogold labeling to examine the topological associations of desmin cytoskeletal and lamin B nucleoskeletal intermediate filaments with various intracellular structures in mammalian cardiac myocytes. We found that desmin filaments form a sarcoplasmic network radiating from the sarcolemma to the nuclear surface. Perpendicular to the long axis of the cell, strands of desmin filaments traverse the interfibrillary space in a co-linear arrangement with Z-discs. The desmin filament strands extend between peripheral regions of adjacent Z-discs. Desmin filaments traversing the interfibrillary space closely associate with the surface of mitochondria. At the cell surface, desmin filaments extend from Z-discs to terminate immediately beneath the sarcolemma. Close to the nucleus, desmin filaments extend from Z-discs towards nuclear pores. At the same time, lamin B filaments, which co-localize with heterochromatin immediately beneath the inner nuclear membrane, encircle the inner aspect of each nuclear pore. We hypothesize that desmin and lamin B are functionally anchored to each other at the nuclear pore, either directly or through anchorage proteins within the pore complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Inappropriate expression of blood group antigens on biliary and colonic epithelia in primary sclerosing cholangitis.

The distribution of carbohydrate antigens of the ABO, Lewis, and Kell systems was examined in biliary and colonic epithelial of 11 patients with primary sclerosing cholangitis (PSC) using a panel of 11 monoclonal antibodies. Controls consisted of 27 liver biopsy specimens (11 normal, six alcoholic liver disease, five extrahepatic obstruction, and five primary biliary cirrhosis) and 24 colonic biopsy specimens (six normal, four Crohn's disease, and 14 ulcerative colitis). There was inappropriate staining with anti-A (four of six, 66%) and anti-B (nine of 11, 81%) in biliary epithelium of PSC patients compared with normal and disease controls. Expression of Lewis antigens was increased in patients with cholestatic liver disease. Ninety one per cent of PSC patients showed a similar pattern of inappropriate staining by anti-A and anti-B antibodies in colonic epithelium compared with 33% of normal and 42% of inflammatory bowel disease controls. There is inappropriate expression of A and B carbohydrate antigens in biliary and colonic epithelium in PSC. Whether these oncofetal antigens are implicated in the pathogenesis of this condition is discussed.

Adult↗
PubMed1993

Many peptides that are present in the external zone of the median eminence are not secreted into the hypophysial portal blood of sheep.

Apart from the well recognized factors that are produced by the hypothalamus and secreted into hypophysial portal blood to regulate pituitary function, there is a range of neuropeptides that are present in the median eminence and could be secreted to serve a modulatory function. In this study we have collected hypophysial portal blood and jugular venous blood from sheep in an attempt to identify which of these putative modulatory peptides might be secreted from the median eminence. We have measured neuropeptide Y (NPY), substance P (SP), galanin (GAL), neurokinin A (NKA), peptide histidine isoleucine (PHI), vasoactive intestinal peptide (VIP), neurotensin (NT) and cholecystokinin (CCK). We also examined the sheep median eminence using immunohistochemistry for NPY, SP and GAL and determined degradation profiles of NPY, SP, GAL and NKA in portal and jugular plasma. In no instance did we find that levels of the above peptides were consistently higher in portal blood than in peripheral blood. In some cases levels of peptide were lower in portal plasma e.g. for NPY (6/10 sheep). In one experimental series SP levels in portal plasma were significantly (p < 0.05) lower than levels in jugular plasma but this was not found in another experimental series. Galanin levels were significantly (p < 0.01) lower in portal plasma compared to levels in jugular plasma. We conducted in vitro studies to determine whether or not the above peptides are selectively degraded in portal blood but were unable to show any differences between the rates of degradation in portal and jugular plasma. Immunohistochemistry revealed projections into the external zone of the median eminence for NPY, GAL and SP. This study shows that none of the above peptides are secreted into the hypophysial portal blood of sheep. For some peptides e.g. GAL, enzymes from the endothelial cells of the portal vessels may enhance degradation. Projections into the external zone of the median eminence of neuronal systems containing these peptides may serve to modulate the secretion of the well recognized release and inhibiting factors by acting on the neurosecretory terminals.

Animals↗
PubMed1992

Antioxidants and the cardiomyopathy of Mg-deficiency.

For several decades the animal models of Mg-deficiency have been studied with particular attention to the cardiomyopathy that develops due to dietary deficiency. In recent years we have studied the effects of nutrients and drugs with antioxidant properties on the development of the cardiomyopathy. We have found that treatment of the Mg-deficient animals with alpha-tocopherol, a naturally-occurring antioxidant, significantly diminishes the number and size of lesions. In addition, treatment with lipophilic drugs with antioxidant properties (probucol, propranolol) or water-soluble drugs that scavenge hydroxyl radicals (captopril, epicaptopril), also provided significant protection. In view of these findings, we suggest that chronic hypomagnesemia results in a pro-inflammatory condition leading to excessive production of oxygen-derived free radicals. Subsequently, the tissue antioxidant capacity is overwhelmed and oxidative tissue destruction results.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Morphologic features and nuclide composition of infarction-associated cardiac myocyte mineralization in humans.

Low dietary Mg results in Ca loading of cardiac myocytes, which increases the likelihood of myocyte calcification in the event of acute myocardial infarction (AMI), and possibly increases myocyte vulnerability to necrosis. Bloom and Peric-Golia1 previously reported an autopsy study of cases from the Washington, D.C. area (a region with low levels of Mg in the drinking water), demonstrating AMI-associated mineralization in myocytes with histologically normal nuclei and cross striations, as well as in obviously necrotic myocytes. The authors have re-examined mineralized myocytes from the same autopsy material, using electron probe microanalysis, light microscopy, and transmission electron microscopy. Microprobe analysis identified Ca and P as the nuclides composing the inorganic phase of the mineral deposits. Ultrastructurally, all Ca deposits, regardless of size or intracellular location, were composed of aggregates of needlelike hydroxyapatite crystals. The mildest form of intracellular Ca deposition was observed as small Ca deposits limited to some mitochondria of myocytes, which demonstrated intact nuclei and regular sarcomere pattern. More advanced stages of intracellular calcification, in the form of Ca deposits associated with mitochondria, Z-band regions and nuclei, were observed in other myocytes that also retained intact nuclei and sarcomeres. Massive Ca deposits were associated with myocytes which showed morphologic features of advanced necrosis, including loss of nuclei, disruption of sarcomere structure and masses of cellular debris. These observations support the theory originally proposed by Bloom and Peric-Golia1 suggesting that Ca loading of myocytes, possibly related to Mg deficiency in humans, increased vulnerability of the myocytes to subsequent AMI-associated necrosis and dystrophic calcification. In addition, the light microscopic impression of calcification of otherwise normal myocytes is contradicted by the electron microscopic identification of hydroxyapatite crystals free in the sarcoplasm, a condition unlikely to be compatible with viability. Lastly, the fact that all Ca deposits were in the form of hydroxyapatite supports the view that they were formed in a Mg-poor environment, which favors conversion of the more common amorphous form of Ca phosphate into the needlelike crystals of hydroxyapatite.

Calcium↗
PubMed1990

Magnesium dietary intake modulates blood lipid levels and atherogenesis.

In this study, we have examined the effects of variation in dietary Mg on the atherogenic process. Oral supplementation of rabbits fed a high cholesterol diet (1% or 2%) with the Mg salt magnesium aspartate hydrochloride (Magnesiocard) (i) lowers the level of serum cholesterol and triglycerides in normal (25-35%) as well as atherosclerotic (20-40%) animals and (ii) attenuates the atherosclerotic process markedly. In addition, we found that dietary deficiency of Mg augments atherogenesis markedly and stimulates (or activates) macrophages of the reticuloendothelial system. Evidence is presented to indicate that the hypercholesterolemic state may cause the loss of Mg from soft tissues to the serum, thereby masking an underlying Mg deficiency.

Animals↗
PubMed1990

Chorioretinal folds and a macular hole secondary to craniofacial surgery.

Chorioretinal folds have been reported as a result of many intraocular and extraocular inflammatory processes or tumors. Visual loss is usually secondary to a combination of the underlying process and chorioretinal folds involving the macula. We report a patient who developed decreased vision, metamorphopsia, chorioretinal folds, and a lamellar macular hole secondary to global compression by a bone fragment. The chorioretinal folds regressed and his vision stabilized following surgical decompression. Chorioretinal folds and lamellar macular hold formation are previously unrecognized complications of reconstructive craniofacial surgery.

Adult↗
PubMed1990

Effects of reduced dietary magnesium on platelet production and function in hamsters.

The increased vulnerability of animals fed a magnesium (Mg)-deficient (MD) diet to ischemia-induced myocardial necrosis has been attributed to changes in myocardial electrolyte metabolism. However, a variety of hematologic changes have also been reported in MD and some of these, such as an increase in platelet aggregability, may contribute to the increased myocardial vulnerability. In the present study, we quantified the effect of MD on platelet and megakaryocyte abundance as well as on platelet aggregability with and without an administered calcium channel blocker (nifedipine). Hamsters were fed either a "minimal Mg" diet, in which the level of Mg was kept just high enough to prevent seizures, or a "preset Mg" diet containing precisely known amounts of Mg. Animals fed the minimum Mg diet showed an initial increase in the platelet count, which returned to control range when the dietary Mg was increased to 9 mmoles/kg. Animals on the preset Mg diet showed an increased platelet count if the Mg level was 10 mmoles/kg or less. In addition to the increase in number, platelets from MD animals were less responsive to the aggregation-inhibiting effect of nifedipine than were platelets from control animals, although MD itself did not result in an increased aggregability under the conditions used here. Animals with an increase in circulating platelets showed decreased megakaryocyte abundance in the femoral marrow, but megakaryocytes that were present were larger than those in control animals. These results indicate a profound effect of dietary Mg deficiency on platelet biology. The observed changes could contribute to the increase in myocardial vulnerability to injury found in MD animals.

Animals↗
PubMed1990

A student health HMO as a partnership model within an academic medical center.

The Department of Family Practice, College of Medicine, in partnership with the University of Illinois at Chicago, was responsible for the reorganization of the Student Health Service into a health maintenance organization (HMO), Campus Care. Historically, the two campuses of the University of Illinois at Chicago operated student health as an infirmary model. Reorganization of student health into the Campus Care HMO provided expanded health care services to students, preserved more health care dollars in the university system, and provided a nonincremental increase in the size and responsibility of the Department of Family Practice. One year's experience showed that while the capitation was low compared with standard HMOs, the variable and less frequent use of services by the student population resulted in a fiscally viable operation. Numerous transition difficulties were encountered, including the need for rapid systems conversion within a complex university system, reeducation of students as well as traditional university-based practitioners for operation in a managed care system, and the rapid expansion of a small family practice department. The positive experience of the University of Illinois at Chicago supports the notion that family practice is better suited to providing student health care than other primary care disciplines. Three issues are paramount to success: (1) approval, support, and protection by higher level administration from university territorialism, (2) a core family practice faculty with strong leadership and experience in high-volume clinical activity, and (3) a close examination of financial resources in light of expected utilization.

Academic Medical Centers↗