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Biomedical subjects

Z Cohen

Publications and source records attributed to Z Cohen.

At least 145 records · Page 8Linked to original sources
PubMed1993

Colon transplantation: a new microvascular technique.

This paper describes a new transplantation technique, using the colon instead of the small bowel for intestinal transplantation. With microsurgical techniques, allogeneic colon transplantation was carried out in rats in a heterotopic fashion. The vascular pedicle containing the aortic cuff and the portal vein was anastomosed to the aorta and the inferior vena cava of the host, respectively. The technique has proven reliable and reproducible, and our preliminary results suggest that the colon produces a milder rejection response than transplantation of the small bowel.

Anastomosis, Surgical↗
PubMed1993

Advanced gastroduodenal polyposis with ras mutations in a patient with familial adenomatous polyposis.

Upper gastrointestinal polyps are being recognized with increasing frequency in patients with familial adenomatous polyposis. Duodenal and periampullary adenomas are the most common type and have poorly understood but definite malignant potential. In contrast, the majority of polypoid lesions in the stomach are benign fundic gland polyps. We report a patient with familial adenomatous polyposis who developed dysplasia in a large exophytic hyperplastic gastric tumor that appeared to arise on a background of diffuse fundic gland polyposis and presented with anemia, hypoalbuminemia, and a protein-losing enteropathy. A large periampullary adenoma also was present. Using the polymerase chain reaction with mismatched primers, a GGT to TGT Kras codon 12 mutation was detected within areas of severe dysplasia in the gastric tumor and in the periampullary adenoma. This case serves to further highlight the spectrum of clinical, pathologic, and molecular features of premalignant upper gastrointestinal tract lesions in patients with familial adenomatous polyposis.

Adenomatous Polyposis Coli↗
PubMed1993

Functional activity in host and graft lymphoid tissue of rats receiving syngeneic heterotopic small bowel transplants with portal or systemic drainage.

Adult Lewis rats received syngeneic accessory small bowel transplants (SBT) with venous drainage to the portal vein (PV) or the inferior vena cava (IVC)/hetero-portal (HP) or hetero-systemic (HS) grafts, respectively. At varying times thereafter (5-300 days post-transplantation) animals were killed and cells from different lymphoid organs were tested in vitro for their generation of lymphoproliferative and cytotoxic T-cell responses, as well as their ability to produce a variety of lymphokines after alloantigen or mitogen stimulation. Despite marked decreases in cell recovery in Peyer's Patches of HS rats, no significant loss of cell function (on a per cell basis) was noted in any animal group. Total recovered activity per organ was decreased in small intestinal tissue (host and graft) of HS recipients regardless of the assay under study.

Animals↗
PubMed1993

Migration patterns of lymphocytes following syngeneic heterotopic small bowel transplantation in rodents.

Adult rats received syngeneic accessory small bowel grafts with venous drainage to either the portal vein (hetero-portal) or the inferior vena cava (hetero-systemic). Lymphoid cell recovery in different lymphoid organs (spleen, pooled peripheral lymph nodes, mesenteric nodes, Peyer's Patches) was evaluated at varying times (days 0-300) post-grafting. While minimal changes were observed for cell recovery in other organ tissues, lymphocyte recovery in Peyer's Patches of both host and graft small intestine of hetero-systemic animals was decreased from 10- to 100-fold with respect to hetero-portal recipients or non-operated controls. These changes were seen throughout the time course of the study. In additional experiments, lymphoid cells from different organs/donors were labelled in vitro with 111In and injected intravenously into normal/transplanted recipients. Recovery of 111In in various organs was assessed at 1 and 6 h postinjection. The major change seen was in the decreased ability of mononuclear cells derived from Peyer's Patches to migrate to small intestinal tissue (host and graft) in hetero-systemic recipients. In addition, Peyer's Patch cells from these animals 'homed' poorly to small intestine in non-operated animals by comparison with cells from normal rats (or hetero-portal donors).

Animals↗
PubMed1993

Bromoalkane-degrading Pseudomonas strains.

Two Pseudomonas isolates, named ES-1 and ES-2, were shown to possess a wide degradative spectrum for haloalkanes in general and bromoalkanes in particular but did not degrade nonsubstituted alkanes. The utilization of water-insoluble haloalkanes, such as 1-bromooctane, appeared to consist of three phases: (i) extracellular emulsification by a constitutively excreted, broad-spectrum surface-active agent, (ii) dehalogenation by an inducible hydrolytic dehalogenase (possibly periplasmic), and (iii) intracellular degradation of the residual carbon skeleton. Several observations suggest the existence of more than one dehalogenase in strain ES-2.

Alkanes↗
PubMed1993

Long-term effect of desalivation on extraction wound healing: a densitometric study in rats.

The study evaluates radiographically the long-term changes that occur during the healing of tooth sockets in a desalivated rat model. Experimental rats underwent sialadenectomy of the submandibular and sublingual glands and ligation of the parotid ducts. Mandibular left first molars were extracted and the rats killed at 0, 14, 21, 28, 45 and 60 days post-extraction. The mandibles were removed, cleaned of soft tissue, placed on a size 2 dental X-ray film and exposed together with an aluminium stepwedge 0.5-3.0 mm. Socket density was measured using a digital densitometer and related to the equivalent density of aluminium. The density of the image of the apical area of the socket was similar in control and desalivated groups (P > 0.05) throughout the study. However, the density of the image of the crestal area of the socket was lower (P < 0.01-0.001) between days 21 and 60 in desalivated rats. This suggests that desalivation causes a long-term delay in socket healing.

Absorptiometry, Photon↗
PubMed1993

Biology of aging in an Israeli population. 1. Review of literature and morphological variation analysis.

This article reports the results of a comparative morphological assessment carried out on five age segments of an Israeli population: 1. neonates, 2. early school age children (6.5-7.5 years old), 3. young adults (18-29), 4. mature adults (30-45) and 5. elderly people (75-94). The aim of the investigation was to analyze the relationship between developmental homeostasis phenomena and the aging process. Developmental homeostasis was assessed via group coefficient of variation (CV) for 21 morphological traits and fluctuating asymmetry (FA) for 8 bilateral traits. The majority of traits was found to show significantly increased CV and FA in the elderly group. This finding is consistent with the hypothesis that the aging process is accompanied by the total breakdown of the individual's developmental stability.

Adolescent↗
PubMed1993

An unusual intraoperative complication of stapled colorectal anastomosis: report of a case and review of the literature.

The unusual intraoperative complication of inadvertent formation of a stapled colovaginal anastomosis is described in a 61-year-old woman with diverticular disease. Intraoperative complications of linear staplers, linear cutters and circular end-to-end anastomotic staplers are reviewed, as are methods of prevention and management of such complications. The discussion focuses mainly on the complications that may arise in low anterior resection. They are more likely due to operator error than to instrument failure.

Acute Disease↗
PubMed1992

Cerebrovascular nerve fibers immunoreactive for tryptophan-5-hydroxylase in the rat: distribution, putative origin and comparison with sympathetic noradrenergic nerves.

The distribution of serotonergic nerves in major basal and isolated small pial arteries (diameter > or = 50 microns) was investigated immunohistochemically using an antibody directed against tryptophan-5-hydroxylase (TPOH), the rate-limiting enzyme in the synthesis of 5-hydroxytryptamine (5-HT or serotonin), and compared to that of the noradrenergic system labeled for the selective noradrenaline (NA) synthesizing enzyme, dopamine-beta-hydroxylase (DBH). In addition, the possible peripheral and/or central origins of the cerebrovascular serotonergic (TPOH-positive) nerve fibers were examined. Strongly labeled TPOH-immunoreactive (TPOH-I) fiber bundles were observed in major basal arteries and gave rise to small varicose fibers organized in a meshwork pattern. The highest density of TPOH-I fibers was found in the middle cerebral artery followed by the anterior cerebral and the anterior communicating arteries, with a moderate to low density in the internal carotid and the vertebro-basilar trunk. Of the isolated pial arteries, only the larger ones (diameter > 75 microns) were significantly endowed with TPOH-I varicose fibers. However, free floating TPOH-I nerves were observed coursing through the pia-arachnoid membranes and reaching small pial vessels. In contrast, DBH-I nerve fibers were fine and were visualized primarily as numerous varicosities distributed in a circumferential manner around the vessel wall. A very high density of DBH-I varicosities was seen in the rostral part of the circle of Willis, with the internal carotid being the most richly supplied followed by the anterior cerebral and the anterior communicating arteries; comparatively, the middle cerebral artery was moderately innervated. The differences in distribution pattern and density between TPOH-I and DBH-I cerebrovascular fibers clearly suggest that these two innervation systems are not exactly superimposable. Superior cervical ganglionectomy caused an almost complete disappearance of TPOH-I nerves in all vascular segments, with some residual fibers in selected vessels. Lesion of the central serotonergic component with the neurotoxin 5,7-dihydroxytryptamine had virtually no effect on the TPOH-I fibers in the major basal and isolated pial arteries. These results strongly suggest that the serotonergic innervation of major cerebral as well as pial arteries has a prominent peripheral origin closely related to the sympathetic system. Processing of superior cervical ganglion slices for TPOH immunocytochemistry, however, failed to unequivocally detect TPOH-I neurons.

5,7-Dihydroxytryptamine↗
PubMed1992

Coping styles, psychopathology and intellectual performance in patients with familial adenomatous polyposis.

Thirty-eight patients with familial adenomatous polyposis (FAP) were compared with 19 patients with ulcerative colitis (UC) for differences in illness-related variables, coping styles, psychiatric symptomatology, and intellectual performance. Patients with FAP had significantly less education, longer time since recent surgery, less psychiatric illness, and evidence of less preoccupation with their illness, as compared with UC patients. FAP patients with a positive family history (N = 28) scored significantly lower on both verbal and performance intellectual tests, even when taking education into account, compared with FAP patients without a family history (N = 9). The relevance of these findings to the ongoing monitoring and surveillance of patients with FAP is discussed.

Adaptation, Psychological↗
PubMed1992

Acute acalculous cholecystitis caused by Salmonella typhi in a 6-year-old child.

A rare case of acute acalculous cholecystitis caused by Salmonella typhi in a 6-year-old child is presented. The clinical signs were fulminant, with diffuse peritonitis being suspected. Cholecystostomy and i.v. ceftriaxone proved efficacious and the girl was discharged in less than two weeks. The appropriate literature is reviewed.

Ceftriaxone↗
PubMed1992

Continuing evolution of the pelvic pouch procedure.

The results of the pelvic pouch procedure were reviewed to assess the surgical complication rate and outcome of patients who had had the procedure performed with a stapled ileo-anal anastomosis with and without a defunctioning ileostomy. Between December 1982 and March 1992, 483 patients underwent a pelvic pouch (PP) procedure. Patients were divided into three groups: group I consisted of 325 patients (178 men and boys and 147 women and girls) who underwent a PP procedure with a handsewn ileoanal anastomosis (IAA) with a defunctioning loop ileostomy. In group II, there were 87 patients (47 men and boys and 40 women and girls) who had a stapled IAA with a defunctioning ileostomy. Group III patients consisted of 71 patients (43 men and boys and 28 women and girls) who had a stapled IAA with no covering ileostomy. Assessment was made of the IAA leak rate, the surgical complications, the reoperation rate, and functional outcome. Early surgical complications included 40 (12%) IAA leaks in group I patients compared with only six (7%) leaks in group II patients who had a stapled IAA (p < 0.05). In group III patients, who had a stapled IAA but no covering ileostomy, there were 13 leaks (18%). Eleven of these 13 leaks healed spontaneously with tube drainage; one patient remains with a rectal tube in place 6 weeks after operation, and only one patient has required a reoperation (defunctioning ileostomy). Functionally, all patients with a healed IAA after a leak have had an excellent result comparable to those without a leak. Patients who were male, older than age 40, on steroids, and had had a true one-stage PP procedure, had a greater risk of developing an IAA leak. In two patients, there was intraoperative difficulty, and one of these patients had an IAA leak after operation. Disease activity at the resection margin and patient weight did not affect the leak rate. Our results suggest that the IAA leak rate is significantly reduced in patients with a stapled IAA with an ileostomy compared with those with a handsewn IAA. Omission of the defunctioning ileostomy is associated with a higher IAA leak rate, but spontaneous healing occurs in almost all patients without impairment of functional results. In patients in whom the ileostomy is omitted, the IAA leak rate is greatest in male patients who have undergone a true one-stage PP procedure, are on steroids, and are older than age 40.

Adenomatous Polyposis Coli↗
PubMed1992

The effects of 16, 16 dimethyl prostaglandin E2 therapy alone and in combination with low-dose cyclosporine on rat small intestinal transplantation.

The use of prostaglandin E (PGE) in the setting of allotransplantation both clinically and experimentally has been suggested because PGE has significant immunosuppressive effects and potentially could lessen the toxic effects of cyclosporine. In the present study, we examined the immunosuppressive effects of 16,16 dimethyl prostaglandin E2 (dmPGE2) alone and in combination therapy with low-dose CsA to assess the clinical course, histology and expression of monocyte/macrophage procoagulant activity (PCA) following small intestinal transplantation in a heterotopic model of rat allograft rejection. Therapy with low-dose CsA (1 mg/kg) failed to prevent rejection and all animals reached a terminal state by day 26. In contrast, animals treated with high-dose CsA (10 mg/kg) showed no clinical or histological evidence of rejection and all animals survived. The dmPGE2 (100 micrograms/kg/twice daily) delayed the onset of rejection, but all animals developed severe rejection and subsequently died. Treatment of animals with low-dose CsA (1 mg/kg) in combination with dmPGE2 (100 micrograms/kg twice daily) resulted in a delay in the onset (P = 0.05) and a reduction in the intensity of allograft rejection (P = 0.0001) compared with either agent used alone. Monocyte/macrophage procoagulant activity levels correlated with the degree of rejection in all animals (P = 0.03). There was a statistically significant relationship between PCA levels and the time of onset of rejection and histologic grade of rejection in all groups. The data presented here, therefore, demonstrate a beneficial role for long-term combination therapy with CsA and PGE in small intestinal transplantation and strongly suggest a role for allogeneic induction of PCA in the pathogenesis of rejection.

16,16-Dimethylprostaglandin E2↗
PubMed1992

Overproduction of gamma-Linolenic and Eicosapentaenoic Acids by Algae.

The pharmaceutical interest and limited availability of gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) prompted the search for genetic means for increasing the production of these fatty acids from algal sources. Cell lines of Spirulina platensis and Porphyridium cruentum resistant to the growth inhibition of the herbicide Sandoz 9785 were selected by serial transfers of the culture in the presence of increasing concentrations of the herbicide. The resistant cell lines of S. platensis overproduced GLA and those of P. cruentum overproduced EPA and were stable for at least 50 generations in the absence of the inhibitor.

Journal Article↗
PubMed1992

Microbiologic assessment of tissue biopsy samples from ileal pouch patients.

Tissue biopsy samples from patients with and without ileal pouches were examined by electron microscopic and microbiologic culture techniques to determine the numbers and types of microorganisms closely associated with or within the tissue biopsy samples. The disease status of each patient was determined by endoscopic and histopathologic methods. Of the 78 biopsy samples included in this study, 64 (82%) yielded obligately anaerobic and/or facultative bacteria when they were cultured. Fourteen of the 78 samples (17.9%) were negative by culture. Of the positive samples, 54 contained facultatively anaerobic bacterial species and 50 yielded obligately anaerobic species. The total counts for facultatively anaerobic bacteria for samples from patients with pouchitis were significantly greater than for samples from patients in control groups. In addition, the number of samples from patients with normal pouches that did not contain obligate anaerobes was significantly less than that from patients with pouchitis; 4 of 23 and 6 of 12 samples, respectively (P less than 0.043). For samples in which organisms were detected, there was agreement with electron microscopic detection of bacteria in 23 of 27 samples, for an overall sensitivity of electron microscopy compared with that of culture of 85%. The qualitative studies resulted in the characterization of 273 isolates comprising 77 different phenotypes. The specificity of these findings in patients with ileal pouchitis is discussed.

Bacteria, Anaerobic↗
PubMed1992

Management of mesenteric desmoid tumours in familial adenomatous polyposis.

Intra-abdominal desmoids are locally invasive fibrous tumours within the mesentery of the intestine. They occur in 4% to 13% of patients with familial adenomatous polyposis (FAP). Of 498 patients registered in the Steve Atanas Stavro FAP Registry at the Mount Sinai Hospital, Toronto, 53 (11%) had desmoids and 40 of them had mesenteric desmoids. There were 23 women and 17 men, and the mean age was 31 years. Most tumours were diagnosed after colectomy for FAP. Of the 40 patients 7 (18%) died of desmoid-related complications. Surgical excision of desmoids is hazardous and was associated with a recurrence rate of up to 85% in this study. Current research is directed at the role of antiestrogens in the fundamental mechanisms of cell growth and are now the subject of clinical trials.

Abdominal Neoplasms↗