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Biomedical subjects

R E Silverman

Publications and source records attributed to R E Silverman.

13 recordsLinked to original sources
PubMed2001

Subcutaneous heparin versus low-molecular-weight heparin as thromboprophylaxis in patients undergoing colorectal surgery: results of the canadian colorectal DVT prophylaxis trial: a randomized, double-blind trial.

OBJECTIVE: To compare the effectiveness and safety of low-dose unfractionated heparin and a low-molecular-weight heparin as prophylaxis against venous thromboembolism after colorectal surgery. METHODS: In a multicenter, double-blind trial, patients undergoing resection of part or all of the colon or rectum were randomized to receive, by subcutaneous injection, either calcium heparin 5,000 units every 8 hours or enoxaparin 40 mg once daily (plus two additional saline injections). Deep vein thrombosis was assessed by routine bilateral contrast venography performed between postoperative day 5 and 9, or earlier if clinically suspected. RESULTS: Nine hundred thirty-six randomized patients completed the protocol and had an adequate outcome assessment. The venous thromboembolism rates were the same in both groups. There were no deaths from pulmonary embolism or bleeding complications. Although the proportion of all bleeding events in the enoxaparin group was significantly greater than in the low-dose heparin group, the rates of major bleeding and reoperation for bleeding were not significantly different. CONCLUSIONS: Both heparin 5,000 units subcutaneously every 8 hours and enoxaparin 40 mg subcutaneously once daily provide highly effective and safe prophylaxis for patients undergoing colorectal surgery. However, given the current differences in cost, prophylaxis with low-dose heparin remains the preferred method at present.

Anticoagulants↗
PubMed2000

A prospective, randomized, double-blind studyof single high dose versus multiple standard dose gentamicin both in combination withmetronidazole for colorectal surgicalprophylaxis.

Single, high dose regimens of gentamicin plus metronidazole for colorectal surgical prophylaxis have not been adequately studied. Patients received single high dose gentamicin (4.5 mg/kg) plus metroni-dazole (500 mg) preoperatively or multiple standard dose gentamicin (1.5 mg/kg) plus metronidazole (500 mg) preoperatively and every 8h for 24h postoperatively. The deep surgical site infection (SSI) rates were 8.1% (6/74) and 6.9% (5/72) in the single high dose and multiple standard dose groups, respectively (P= 0.94). There was a trend towards fewer superficial SSIs in the single high dose group with infection rates of 18.9% (14/74) vs. 30.6% (22/72) (P= 0.05). Diabetes mellitus (odds ratio = 7.04) and surgery duration of longer than 3h (odds ratio = 5.46) were independent risk factors for the development of SSIs. A subset analysis of prolonged operations found significantly fewer superficial SSIs in the single high dose group than in the multiple standard dose group with rates of 22.2% (6/27) vs. 55% (11/20), respectively (P= 0.021). Single high dose gentamicin plus metronidazole preoperatively was at least as effective as the multiple standard dose regimen and may be more effective for prolonged operations.

Aged↗
PubMed1993

Effect of multiple risk factors on differences between blacks and whites in the prevalence of non-insulin-dependent diabetes mellitus in the United States.

The higher prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in US blacks as compared with whites may be due to a higher frequency of NIDDM risk factors in blacks, a higher inherent susceptibility to NIDDM among blacks, or the risk factors' having a greater effect in blacks. The authors evaluated 4,379 subjects from the Second National Health and Nutrition Examination Survey (1976-1980) for whom NIDDM was ascertained by medical history and oral glucose tolerance test, and for whom data on a number of risk factors were available. The prevalence of NIDDM was 60% higher in blacks than in whites (p < 0.001) and was highest in black women. Although most risk factors for NIDDM were more common in blacks, this higher frequency did not completely explain the racial disparity in the prevalence of NIDDM. After adjustment for all risk factors by logistic regression, an elevated risk of NIDDM was particularly evident at higher obesity levels in blacks as compared with whites; the odds were 70% higher for blacks at a percentage of desirable weight of 150 (95% confidence interval 1.1-2.8). The risk of NIDDM associated with obesity was greatest in black women: The odds in this group were sevenfold higher at a percentage of desirable weight of 150 versus 100 (95% confidence interval 2.6-18.8). The possibility of racial differences in metabolic adaptation to obesity highlights the importance of preventing this condition in blacks, particularly in black women.

Adult↗
PubMed1993

Survey of physician practice behaviors related to diabetes mellitus in the U.S. I. Design and methods.

OBJECTIVE: To conduct a survey among a representative sample of primary care physicians in the U.S. to assess practice behaviors, treatment goals, and beliefs related to management of diabetes mellitus and prevention of its complications. RESEARCH DESIGN AND METHODS: A mail survey with telephone follow-up was conducted among 3481 primary care physicians in active practice in the continental U.S. A stratified probability sample was selected using the files of the American Medical Association and American Osteopathic Association. Four specialties were selected to be included in the study: family physician, general practitioner, internist, and pediatrician. Two versions of a questionnaire were constructed: one for pediatricians containing questions about IDDM only and one for the other three specialties containing questions about both IDDM and NIDDM. Physicians who were not actively engaged in practice or did not see patients with diabetes were excluded. RESULTS: Completed questionnaires were received from 1502 of 3481 sampled physicians. Based on various assumptions of eligibility among nonresponders, an overall response rate to the survey was estimated to be between 65.7 and 86.5%. Discrepancies between specialty identifications as noted on the American Medical Association/American Osteopathic Association files and as self-designated were noted. CONCLUSIONS: This report describes the methodology used in the design and conduct of the survey, and data are provided to document the technical success of survey execution. This report provides the methodological basis for a series of separate reports on demographic characteristics of the physicians, their practices and their patients, and on specific attitudes, beliefs, and practice behaviors of primary care physicians in the U.S. with regard to diabetes mellitus.

American Medical Association↗
PubMed1989

Monocyte/macrophage procoagulant activity as a measure of immune responsiveness in Lewis and brown Norway inbred rats. Discordance with lymphocyte proliferative assays.

In vitro lymphocyte proliferative assays were performed using Lewis (Lew) and Brown Norway (BN) rats, and compared to induction of monocyte/macrophage procoagulant activity (PCA) in a mixed lymphocyte culture and by endotoxin (LPS) (E. Coli 0111:B4). Splenic mononuclear cells from Lew rats had significantly greater mitogen-induced proliferation to concanavalin A (P = .002) and phytohemagglutinin (P = 0.007). The Lew cells also showed greater allogeneically induced proliferation by BN cells in a one-way MLC in comparison to the reciprocal BN proliferative response (P less than 0.04). PCA induction in peripheral blood mononuclear cells (PBM) by allogeneic stimulation in MLC or total content PCA by LPS did not vary significantly between the 2 strains (P greater than 0.5). Induction of PCA by LPS was rapid, with a moderate rise over basal activity at 3 hr and maximal activity at 6 hr. Two-way allogeneic induction of PCA in PBM from BN and Lew rats resulted in PCA elevation by 3 hr, which became maximal at 18 hr. One-way MLC with Lew or BN cells as responders resulted in moderate increases in PCA by 3-6 hr, with equivalent maximal activities recorded at 18 hr. Viable PCA accounted for 26-32% of total content PCA in both Lew and BN rats. Maximal allogeneic PCA induction by MLC was 14-18% of PCA induced by LPS and required a longer incubation for its expression. Our results indicate that in vitro PCA expression by Lew and BN PBM following allogeneic or endotoxin stimulation shows little interstrain variability in comparison to lymphocyte proliferative responses. Thus PCA appears to more closely reflect the observed in vivo responses of these strains to allogeneic challenge.

Animals↗
PubMed1989

Strictureplasty in Crohn's disease.

Strictureplasty may eliminate or decrease the extent of resection required in patients who have obstructing Crohn's disease of the small bowel. The authors performed 36 strictureplasties at 16 operations in 14 patients. Additional bowel resection was carried out in 13 of the 16 procedures. Early complications included wound infection in one patient, upper gastrointestinal bleeding in one and presumed suture-line leak, treated conservatively, in a third patient. At the end of the follow-up period (mean 16.1 months), 10 patients were asymptomatic and 4 had symptomatic recurrences; 2 of these required reoperation. A number of preoperative factors and operative techniques may have contributed to the favourable results.

Adolescent↗
PubMed1987

Epidermal growth factor binding protein: identification of a different protein.

Partial amino acid sequence analysis of epidermal growth factor binding protein (EGF-BP), an arginine esteropeptidase that specifically associates with EGF to form a high molecular weight complex in male mouse submandibular glands, has revealed a single, distinct protein that is different from three previously reported forms of EGF-BP. This protein shows substantial sequence homology with these other putative forms of EGF-BP as well as with a large family of kallikreins expressed in the mouse submandibular gland. Purified EGF-BP contains three polypeptide chains as a result of two internal cleavages at residues 87-88 and 140-141. These modifications may represent processing events that are critical for determining the binding specificity of EGF-BP, since they occur within regions surrounding the substrate binding site.

Amino Acid Sequence↗
PubMed1986

Small intestinal transplantation using cyclosporine. Report of a case.

A case of small intestinal allotransplantation is described. Cyclosporine and Solumedrol were used for immunosuppression. A hemolytic episode occurred, caused by anti-A antibodies derived from graft lymphocytes. Sudden severe encephalopathy developed on the ninth postoperative day, followed by intractable hypotension and death. Hepatic and splenic microinfarcts were identified on postmortem examination. Allograft rejection was identified by serial stomal biopsies and correlated with a rise in monocyte procoagulant activity, a potentially useful serologic marker of rejection. The absence of an anatomic circuit for recycling of cyclosporine did not alter serum radioimmunoassay/high-performance liquid chromatography ratios.

Adult↗
PubMed1985

Insulin receptors and bioresponses in a human liver cell line (Hep G-2).

A newly developed human hepatoma cell line, designated Hep G-2, expresses high-affinity insulin receptors meeting all the expected criteria for classic insulin receptors. 125I-insulin binding is time-dependent and temperature-dependent and unlabeled insulin competes for the labeled hormone with a half-maximal displacement of 1-3 ng/ml. This indicates a Kd of about 10(-10) M. Since Scatchard analysis of the binding data results in a curvilinear plot and unlabeled insulin accelerates the dissociation of bound hormone, these receptors exhibit the negative cooperative interactions characteristic of insulin receptors in many other cell and tissue types. Proinsulin and des(Ala, Asp)-insulin compete for 125I-insulin binding with 4% and 2%, respectively, of the potency of insulin. Anti-(insulin receptor) antibody competes fully for insulin binding. The two insulin-like growth factors, multiplication-stimulating activity and IGF-I are 2% as potent as insulin against the Hep G-2 insulin receptor. Furthermore, Hep G-2 cells respond to insulin in several bioassays. Glucose uptake, glycogen synthase, uridine incorporation into RNA and acetate incorporation into lipid are all stimulated to varying degrees by physiological concentrations of insulin. In addition, these cells 'down-regulate' their insulin receptor, internalize 125I-insulin and degrade insulin in a manner similar to freshly isolated rodent hepatocytes. This is the first available human liver cell line in permanent culture in which both insulin receptors and biological responses have been carefully examined.

Cell Line↗
PubMed1982

Nerve growth factor: subunit interactions in the mouse submaxillary gland 7S complex.

Sedimentation velocity analyses of the isolated subunits of mouse 7S nerve growth factor (NGF) and their binary complexes have been performed. The 2.5S (beta) form of NGF binds 2 alpha subunits independent of the presence of gamma subunits. Two gamma subunits are also complexed by 2.5S NGF; however, this interaction is dependent on the presence of a carboxyl terminal arginine residue on the beta polypeptide chain. The partial loss of this residue in 2.5S NGF preparations results in a ternary complex(es) with a reduced sedimentation coefficient(s). The two binary complexes formed (alpha 2-beta and beta-gamma 2) show markedly different pH stability profiles. The alpha and gamma subunits do not form a demonstrable complex, but apparently can interact in the ternary complex to render it more stable than the sum of the alpha-beta and beta-gamma interactions.

Animals↗
PubMed1981

Electrophoretic heterogeneity and polypeptide chain structure of the gamma-subunit of mouse submaxillary 7 S nerve growth factor.

The gamma-subunit of the high molecular weight form of mouse submaxillary gland nerve growth factor is known to be electrophoretically heterogeneous. The protein is a mixture of molecules containing either two or three chains, attached covalently by disulfide bonds, that arise from one or two endoproteolytic cleavages. Analysis of the amino acid composition and partial sequence of the resultant fragments has defined the location of the two cleavage sites. Further heterogeneity is generated by partial removal of the carboxyl-terminal basic residues located at the internal cleavage sites, presumably by an endogenous exopeptidase(s) with carboxypeptidase B specificity. Permutations of these endo- and exoproteolytic cleavages generate six possible microheterogeneous forms, which can account for the five major bands observed on electrophoresis at pH 7.05 and the three principal forms seen on isoelectric focusing.

Amino Acid Sequence↗