Biomedical subjects
Publications and source records attributed to I Wasserman.
We consider a model with two parallel (positive tension) 3-branes separated by a distance L in five-dimensional spacetime. If the interbrane space is anti--de Sitter, or is not precisely anti--de Sitter but contains no event horizons, the effective four-dimensional cosmological constant seen by observers on one of the branes (chosen to be the visible brane) becomes exponentially small as L grows large.
OBJECTIVE: To evaluate our incidence of inflammatory fibroid polyps, compare our experience with that of others, and to analyze the possible pathophysiological and aetiological factors. DESIGN: Retrospective review. SETTING: Teaching hospital. MATERIAL: All histopathological slides of the gastrointestinal tract. MAIN OUTCOME MEASURES: Incidence and treatment in our Medical Center and elsewhere. RESULTS: We could find only one case of inflammatory fibroid polyp, an estimated incidence of 1/4000. Between 1987-1996 only 331 were reported elsewhere, most of which (293, 88.5%), were located in the stomach. CONCLUSION: Primary mucosal damage can expose the stroma to several irritants (chemical, mechanical and biological), that may subsequently cause inflammatory fibroid polyps in certain people.
Malignant tumors of the small intestine are rare. An uncommon finding of leiomyosarcoma located in the fourth part of the duodenum was diagnosed by gastrointestinal contrast studies, CT and angiography. Although malignant lesions of the small bowel are usually diagnosed late and thus are far advanced, curative resection was possible in our case. The location and histology of the tumor permitted a 'pancreas-preserving segmental duodenectomy'. The operative approach and exposure using the Cattell maneuver is described. It is emphasized that the more extensive pancreatoduodenectomy should be reserved for adenocarcinomas or lesions situated in the proximal part of the duodenum. Thirteen years following the operation, the patient is asymptomatic while CT and gastrointestinal contrast studies reveal no evidence of disease.
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Intestinal welding by means of low-power laser has been reported as an efficient method for intestinal anastomosis. We designed an experimental model in rats to investigate collagen and DNA concentrations in CO2 laser-welded anastomoses as compared with those in sutured anastomoses on the 4th, 7th, and 10th postoperative days. The results revealed that DNA, total collagen, and insoluble collagen concentrations were significantly lower in the lased anastomoses than in the sutured anastomoses on the 4th postanastomotic day. On the 7th and 10th postanastomotic days, collagen concentrations increased in the laser-treated group attaining significantly higher levels than in the sutured group at that time. These findings are compatible with other studies demonstrating that laser-welded intestinal anastomoses are more prone to dehiscence during the first 4 postanastomotic days, but become at least as effective as the sutured ones with passage of time.
The present study, which contained a sample of 3,948 suicides and controls for seasonal effects, did not replicate the results of Barraclough and Hughes's (1987) study. People are not significantly more likely to die near the time of their birthdays than they are at other times of the year.
All patients (284, mean age 70.8 years) admitted with a diagnosis of primary colorectal cancer to our surgical department during the years 1984-87 were evaluated prospectively. We compare 170 (59.9%) patients > 70 years old and 114 (40.1%) patients < or = 70 years. The overall operability rate was 97.3% and the resectability rate 92.8%. The overall operative mortality rate was 2.1%, four patients in the older group and two patients in the younger group (NS). Among patients who underwent emergency surgery, the operative mortality was 6.1% (4 patients). The overall morbidity rate was 26.7% without significant differences between the two age-groups. A separate subset analysis was done to compare the very old patients (age > or = 80) to the old patients (age 70-79). There were no significant differences between these groups in tumor location, presentation and staging, as well as in operability rate and operative morbidity and mortality. The operative mortality in those over the age of 80 was 3.5%. We concluded that age should not be a determinant in consideration of operation for primary colorectal cancer, since operative mortality and morbidity are similar in both the elderly and their younger counterparts.
Spontaneous pneumothorax is a serious though infrequently reported pulmonary complication of AIDS. An unsuspected lung collapse was discovered via gallium scintigraphy for the study of Pneumocystis carinii pneumonia. Neither the pneumonia nor the pneumothorax were apparent on the most recent chest roentgenogram. In evaluating gallium images during the work-up of AIDS patients with associated pulmonary pathology, the possible complication of lung collapse should be considered. If pneumothorax is suspected on gallium imaging, a chest roentgenogram in expiration must be obtained for prompt delineation of this serious, yet correctable, condition.
Acute perforation of a duodenal ulcer in a patient over of 70 years of age is associated with a high death rate. During a 10-year period, 35 such patients were operated on; in all omentopexy was performed. Two courses of the disease were observed: the first (19 patients) was defined by acute disease of less than 24 hours' duration preceding surgery; the second (16 patients) was of longer duration, starting with various abdominal complaints and presenting more severely only after the first 24 hours. Postoperative death rates were 0% in the first group and 50% in the second. Other factors that were studied, including diabetes mellitus, presence of concomitant malignant diseases and intake of ulcerogenic drugs, had no significant effect on the outcome in these patients.
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To determine the causes and time course of onset of functional asplenia in adults, a four-part investigation was conducted. This consisted of a review of the world's literature, a survey of colleagues, a detailed study of 4,476 consecutive liver-spleen scans in three hospitals, and continued monitoring of 3,500 scans in five hospitals. Based on the findings, a classification was proposed of the causes of functional asplenia. The two major etiologies were circulatory disturbances and effects directly on splenic reticuloendothelial cells. The time course varied from the essentially instantaneous onset of functional asplenia in patients with acute splenic artery obstruction, to a prolonged and gradual onset in those with chronic damage to splenic reticuloendothelial cells. Functional asplenia was found in 0.14% of the adults who had liver-spleen scans for other indications.
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