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S M Greenstein

Publications and source records attributed to S M Greenstein.

67 records · Page 4Linked to original sources
PubMed1986

Evaluation of polylactic acid-carbon mesh for repair of ventral herniorrhaphy.

Large ventral hernias are a difficult surgical problem. Previous attempts to repair large defects in the abdominal wall with prostheses have been associated with recurrences and infection. A filamentous polylactic acid-carbon tissue mesh is a possible alternative prosthesis. We evaluated and compared polylactic acid-carbon mesh and Marlex mesh in repairing a large defect of the abdominal wall in a rat model. The polylactic acid-carbon mesh led to as strong a repair as Marlex mesh for the same time periods postoperatively; furthermore, no infection was noted with the former, whereas a 5.3 percent incidence of infection was noted with Marlex mesh. One mesh disruption was also noted with Marlex mesh. Polylactic acid-carbon mesh was found to have a more marked fibrotic response and a lesser inflammatory response. Polylactic acid-carbon mesh, therefore, appears to be more biocompatible, with more fibrosis, less inflammatory reaction, and equal strength to Marlex mesh. It is therefore a more appropriate synthetic material for a large ventral herniorrhaphy.

Abdominal Muscles↗
PubMed1985

Effect of surgery on tumor-induced accelerated coagulation in a rat carcinoma.

Accelerated coagulation detected by thromboelastography has been reported in early stages of tumor growth. The present investigation was conducted to determine the changes in tumor-induced accelerated coagulation following complete and partial resection of the tumor. Male Fisher rats were divided into four groups: (1) control, (2) tumor-bearing rats, (3) complete resection, (4) partial resection. In groups 2, 3, and 4 a 2-mm3 piece of squamous cell carcinoma (NCI 11095) was implanted subcutaneously in the left flank. Seven days later blood samples were obtained from the tumor and control groups and tested on a thromboelastograph to determine the effect of the tumor on the coagulation of the hosts. Six weeks following the initial tumor implantation a sham operation was performed on group 2, complete resection on group 3, and a partial resection on group 4. After a rest period of 3 weeks blood samples were obtained from the four groups of rats and tested on a thromboelastograph. The results indicate that there is a significant acceleration of coagulation in tumor-bearing animals. The effect of surgery on this tumor-induced phenomenon depends on the type of procedure performed. Complete resection returns the coagulation status toward normal whereas sham operation or a partial resection do not. In this tumor model, hypercoagulability of the blood, therefore, indicates the presence of residual tumor.

Animals↗
PubMedDate not supplied

Urine cytology and the diagnosis of renal allograft rejection. I. Studies using conventional staining.

OBJECTIVE: To determine the reproducibility and validity of urine cytology for the diagnosis of acute renal allograft rejection (AR). STUDY DESIGN: We conducted a blind, prospective study of 10 renal allograft recipients. Freshly voided aliquots of urine were obtained on each hospital day and at each outpatient visit for a mean of 52.8 +/- 26.2 (SD) days following transplantation. The samples were prepared by cytocentrifugation and then stained by a modified Papanicolaou method. To determine interobserver reproducibility, the differential cell counts of two blinded cytopathologists were compared. A cytodiagnosis of AR was made when the urine sample contained < 55% neutrophils and > 20% lymphocytes. To determine the validity of the cytology, the result was compared to the histologic and clinical diagnoses. Biopsies were obtained one hour following vascular anastomosis and at the time of graft dysfunction and were scored by two blinded pathologists according to the Banff classification. The clinical diagnosis was determined by a retrospective review conducted by four blinded clinicians. RESULTS: The interoperator reading of urine cytology was more reproducible than histology, with kappa values of 0.40 +/- 0.15 (SE) and 0.21 +/- 0.10 (SE), respectively. Urine cytology was accurate for the diagnosis of AR, with a sensitivity of 80% and a specificity of 96% as compared to the clinical and histologic findings. CONCLUSION: Our observations support the claim that urine cytology is useful for diagnosing AR.

Acute Disease↗
PubMedDate not supplied

Urine cytology and the diagnosis of renal allograft rejection. II. Studies using immunostaining.

BACKGROUND: Urine immunocytology may provide a noninvasive method of investigating the antigens expressed by renal tubular cells. In previous investigations of patients with acute renal allograft rejection (AR), we showed that the adhesion molecule ICAM-1 is expressed by voided tubular cells. The up-regulation of ICAM-1, in turn, may be due to high circulating levels of interferon-gamma and/or TNF-alpha. We investigated the regulation of receptors for these cytokines and found a correlation between their expression and clinical events. STUDY DESIGN: For 10 patients who received transplants consecutively, freshly voided aliquots of urine were obtained on each hospital day and on each outpatient visit for a mean of 52.8 +/- 26.2 (SD) days. After cytocentrifugation, the samples were prepared by the avidin-biotin-immunoperoxidase technique in order to detect the presence or absence of ICAM-1, interferon-gamma receptor and TNF-alpha receptor (p 80) on the tubular cells. RESULTS: In nonrejecting patients, the tubular cells expressed the interferon-gamma receptor but not ICAM-1 or the TNF-alpha receptor. In patients with AR, the pattern was different. The tubular cells expressed ICAM-1 and the TNF-alpha receptor but not the interferon-gamma receptor. CONCLUSION: Urine immunocytochemistry may be useful to demonstrate the expression of cytokine receptors by renal epithelia.

Adult↗
PubMedDate not supplied

Analysis of adhesion molecule expression by tubular epithelial cells using urine immunocytology.

On their surface, renal tubular cells present intercellular adhesion molecule-1 (ICAM-1) during acute renal allograft rejection. We propose that the extent of ICAM-1 expression by renal tubular cells can be estimated from urine immunocytology. To test this hypothesis, we obtained 52 samples of urine from 31 renal transplant recipients with either acute tubular necrosis, rejection or stable renal function. Cytocentrifuged aliquots of urinary sediment were incubated with monoclonal antibodies to ICAM-1 in an avidin-biotin-peroxidase technique. To corroborate our findings, biopsy specimens were obtained for conventional and immunohistology one hour following vascular anastomosis and during rejection episodes. The proportion of renal tubular cells that expressed ICAM-1 was low in patients with acute tubular necrosis (23.8 +/- 3.6%) and high in patients with rejection (53.1 +/- 4.4% [SEM]) (P < .001). In 11 patients who recovered from rejection, the proportion of ICAM-1-positive renal tubular cells decreased from 55.9 +/- 5.6% to 25.5 +/- 4.3% (P < .05). In two patients who initially had acute tubular necrosis and then rejected their transplants, the expression of ICAM-1 on renal tubular cells tended to increase (from 27.5 +/- 2.5% to 60.0 +/- 20.0%, P = .12). In eight patients with acute tubular necrosis who never rejected their transplants, ICAM-1 expression remained low (23.1 +/- 3.8%). Immunocytology correlated well with immunohistology and the clinical diagnosis. Our findings suggest that urine immunocytology may be useful in monitoring adhesion molecule expression by renal tubular cells.

Adult↗