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Biomedical subjects

R Udassin

Publications and source records attributed to R Udassin.

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

[Laparoscopic surgery in children and adolescents].

Laparoscopic surgery is a rapidly developing field in general surgery. The advantages of laparoscopic procedures are short postoperative courses, fewer wound-related complications, possible reduction in rate of late postoperative adhesions and better cosmetic results. Laparoscopic procedures are indicated in well-defined clinical settings, after enough experience has been acquired and technical problems solved. Children and adolescents may also benefit from laparoscopic procedures. The technique is suitable for cholecystectomies, appendectomies in selected cases, splenectomies, anti-reflux procedures, bowel resections, and diagnostic procedures, among others. In the past 3 years we have performed 65 laparoscopic procedures in patients younger than 17 years, including 10 cholecystectomies, 31 appendectomies and 7 Nissen fundoplications.

Adolescent↗
PubMed1994

The time sequence of injury and recovery following transient reversible intestinal ischemia.

Intestinal mucosal damage and regeneration were examined in rats following transient ischemia produced by the occlusion of the superior mesenteric artery for 30 min. Animal groups were assigned for harvesting of small bowel specimens at 10, 17, and 30 min and 1, 2, 3, 4, 6, 12, and 24 hr post-relief of ischemia. Severe damage to the villi was evident already at 10 min postischemia. Thereafter a very rapid restitutional process was observed with restoration of villi epithelium in 47.6% of the examined animals at 60 min, 75% at 4 hr, and 100% at 12 hr. This rapid sequence of events should be taken into consideration when designing experimental ischemic bowel animal models and possible therapeutic modalities.

Animals↗
PubMed1994

A pitfall in the technique of jejunal tube insertion, resulting in jejunal perforation.

Enteral feeding by a jejunostomy tube is a reliable and cost-effective method for both long- and short-term nutritional support in selected patients, although a high complication rate has been reported in some series. The authors report on jejunal perforation in an infant, caused by a kinked jejunostomy tube, and emphasize this possible pitfall as a warning to others.

Enteral Nutrition↗
PubMed1994

Epidural anesthesia accelerates the recovery of postischemic bowel motility in the rat.

BACKGROUND: Intestinal ischemia is associated with derangement of gastrointestinal motility. Uncontrolled clinical observations that bupivacaine injected into the epidural space causes faster recovery of bowel motility after various abdominal operations led us to assess the hypothesis that epidural anesthesia can hasten the recovery of gastrointestinal motility in the immediate postischemic period. METHODS: Gut motility studies were performed in rats in which epidural anesthesia and intestinal ischemia could be initiated without the need to provoke surgical trauma. Epidural lidocaine was compared to epidural saline in their effect on intestinal motility after a 30-min period of bowel ischemia. RESULTS: Total ischemia to the small bowel resulted in pronounced postischemic adynamic ileus as evidenced by only 0.7% of the total length of the small bowel filled with a marker meal at the end of the study period (transit index) compared with 84.4% in the control group. Lidocaine epidural anesthesia caused significantly more rapid resolution of the adynamic ileus (60.3% of the bowel filled with the marker meal vs. 30.9% in the controls in which saline was injected). CONCLUSIONS: Epidural lidocaine compared to epidural saline hastens the recovery of gastrointestinal motility in rats after a 30-min period of bowel ischemia. This effect may be elicited by attenuation of sympathetic efferent inhibitory pathways or by vasodilatation caused by the sympathetic block. These results suggest that lidocaine epidural block not only alleviates pain in situations of ischemic injury to the bowel but may also hasten the recovery from postischemic paralytic ileus.

Anesthesia, Epidural↗
PubMed1993

[Spontaneous splenic rupture associated with facial erysipelas].

Spontaneous rupture of the spleen is rare Although over 100 cases have been reported, only a few were of true spontaneous rupture. Most cases were associated with diseases which directly involved the spleen. We report a 53-year-old woman with facial erysipelas and true spontaneous rupture of the spleen.

Erysipelas↗
PubMed1993

A simple and rapid method for staining the enteric ganglia: application for Hirschsprung's disease.

A simple and reliable method is described for staining the nerve plexuses of the human gastrointestinal tract in whole-mounts. The staining does not require fixation and consists of a single step of 6 to 10 minutes incubation in a solution of the fluorescent dye 4-(4-diethylaminostyryl)-methylpyridinium iodide. Aganglionic bowel specimens from 6 patients with Hirschsprung's disease were stained by this method and displayed the absence of ganglion cells and an abundance of nerve fibers in the myenteric and submucosal plexuses. This staining may be suitable for the diagnosis of Hirschsprung's disease.

Child, Preschool↗
PubMed1992

Nissen fundoplication in the treatment of children with familial dysautonomia.

Thirty-four children with familial dysautonomia (FD) underwent Nissen fundoplication and gastrostomy. The indications for operation were persistent cyclic vomiting that resulted in repeated aspiration pneumonia (94% of the patients), chronic dehydration (82%), failure to thrive (97%), and frequent hospitalizations (76%). There was no operative or early postoperative mortality. Long-term follow-up for up to 12 years was available. Eight patients died during this period from 7 months to 7.5 years postoperatively. In 5 patients (15% of the operated patients), the fundoplication ceased to function 16 months to 5 years postoperatively, which was attributed mainly to repeated severe dysautonomic crises with vigorous retching. Vomiting ceased in 85% of the symptomatic patients; pulmonary deterioration was halted, and the frequency of aspiration pneumonia was reduced in 68%; nutritional improvement was seen in 44%; the hydration status improved in 88%; and the frequency of hospital admissions decreased in 74%. These long-term findings resulted in a significant improvement in the quality of life for the majority of the patients. The absence of operative mortality and the low postoperative morbidity, together with the long-term beneficial results of this surgical procedure, should encourage early surgical intervention in selected FD patients.

Adolescent↗
PubMed1992

Eicosanoids in hypoxic insult to neonatal rabbit bowel.

Eicosanoids, derivatives of arachidonic acid, play a role in several inflammatory diseases of the bowel. To determine whether prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and leukotriene C4D4E4 (LTC4D4E4), have a role in hypoxic insult to the intestine, we examined the levels of these mediators in a hypoxic neonatal rabbit model. One group of animals underwent hypoxic insult postnatally, the second group did not undergo hypoxia and served as a control. The levels of PGE2, LTB4, and LTC4D4E4 were determined by radioimmunoassay. PGE2 in the hypoxic group was 1,779 +/- 142 pg/mg protein (mean +/- SD) as opposed to 2,380 +/- 197 pg/mg protein in the control group (p less than 0.02). LTB4 level was 5,446 +/- 3,492 pg/mg protein in the hypoxic rabbits and 3,362 +/- 2,570 pg/mg protein in the control group (p less than 0.03). There was no statistically significant difference in the level of LTC4D4E4 between the two groups. Our study shows that hypoxia shifts the arachidonic acid metabolism toward enhanced lipoxygenase activity with a resultant increase in LTB4 levels and a concomitant decrease in cyclooxygenase activity with reduced PGE2 levels in the bowel. The shift in the balance between these eicosanoids may play a role in the pathogenesis of ischemic-hypoxic bowel diseases by enhancing the inflammatory response in the intestine, and simultaneously, diminishing cytoprotection.

Animals↗
PubMed1991

Acquired tracheoesophageal fistula in infancy and childhood.

Acquired tracheoesophageal fistula (TEF) is a rare entity in the pediatric age group. We report two pediatric patients with acquired TEF caused by shells of pistachio nuts. In both patients the primary operation did not resolve the problem and a second intervention for recurrent fistula was needed. The special nature of acquired TEF, particularly the one described herein, requires delayed surgical intervention and meticulous separation of the respiratory and alimentary tracts by an intercostal muscle flap.

Child, Preschool↗
PubMed1991

Feeding jejunostomy for post-operative nutritional support.

Enteral feeding by tube jejunostomy, inserted during definitive surgery, was used in 19 adult patients operated upon in a 24 month period. Jejunostomy feeding was associated with a low rate of minor complications enabling delivery of adequate caloric and protein input shortly after major abdominal operations and up to 9 months later. We feel that the insertion of a regular size jejunostomy tube during surgery is a simple, brief and safe procedure which offers efficient and inexpensive nutritional support, and thus has an important role in the post-operative management of selected patients. It is also easily used in the home setting if needed.

Journal Article↗
PubMed1991

Salicylate as an in vivo free radical trap: studies on ischemic insult to the rat intestine.

Ischemia of rat intestine was induced in vivo by occlusion of the superior mesenteric artery (SMA) for 15 min. Sodium salicylate, 100 mg/kg, given IP, 30 min prior to the ischemic event served as a specific trap for hydroxyl radicals. Portions of the bowel were sequentially isolated and removed--2 min prior to ischemia, 2 min prior to declamping of the SMA, and 10 min following reperfusion. The bowel segments were homogenized in 3% TCA. The homogenate was centrifuged and filtrated through a 0.22 mu filter. The hydroxylation products of salicylate, dihydroxybenzoic acid (DHBA) derivatives, were isolated, identified, and quantified by HPLC coupled with electrochemical detection (ECD). The level of 2,5-DHBA (M +/- SE, ng/g tissue) in the preischemic bowel (N = 21) was 241.8 +/- 10.0. In the ischemic specimen the level of 2,5-DHBA increased significantly to 313.3 +/- 15.5 (p = 0.0129), and remained unchanged in the reperfusion period (322.8 +/- 15.5). The histological examination correlated well with these levels: mild villi damage in the ischemic period with no further exacerbation during the reperfusion period. This study in an in vivo animal model of intestinal ischemia-reperfusion provides direct evidence for the involvement of free radicals during the ischemic insult.

Animals↗
PubMed1991

Direct evidence for the involvement of free radicals in ischemic insult to the intestine.

Ischemia of rat intestine was induced in vivo by occlusion of the superior mesenteric artery (SMA) for 15 min. Sodium salicylate, 100 mg/kg, given IP, 30 min prior to the ischemic event served as a specific trap for hydroxyl radicals and provided direct evidence for the involvement of free radicals during the ischemic insult. Portions of the bowel were sequentially isolated and removed. The hydroxylation products, dihydroxybenzoic acid (DHBA) derivatives were isolated, identified and quantified by HPLC coupled with electrochemical detection (ECD). The level of 2,5-DHBA (Mean +/- SE, ng/g tissue) in the preischemic bowel (N = 21) was 241.8 +/- 10.0. It rose significantly to 313.3 +/- 15.5 in the ischemic specimen (p = 0.0129) and remained unchanged in the reperfusion period (322.8 +/- 15.5). The histological examination correlated well with these levels: mild villi damage in the ischemic period with no further damage in the reperfusion period.

Animals↗
PubMed1991

Mechanistic aspects of 1-methyl-4-phenyl pyridinium iodide toxicity in Escherichia coli: the role of oxygen and hydrogen peroxide.

1-Methyl-4-phenyl pyridinium iodide (MPP+) and paraquat (PQ+2) are two structurally analogous and highly toxic pyridinium compounds. The mechanism of PQ+2 toxicity is best understood in the bacterial model system. While numerous studies in a variety of systems have indicated the causative role of free radicals and other oxygen-derived active species in PQ+2 toxicity, this question is yet unresolved in the case of MPP+. In this study we have used the Escherichia coli model and demonstrated that MPP+ is toxic to bacterial cells in dose- and time-dependent modes. Additionally, it is shown that only in the presence of molecular oxygen did bacterial inactivation occur. This requirement for oxygen can be circumvented by adventitious H2O2. The protective effects of the chemical scavenger--mannitol--and of histidine are presented. These results are in complete accord with a free radical mechanism for MPP+ toxicity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1991

MPP+ toxicity in E. coli under aerobic and anaerobic conditions.

MPP+ and paraquat (PQ+2) are two structurally analogous and highly toxic pyridinium compounds. The mechanism of PQ+2 toxicity is best understood in the bacterial model system. While numerous studies, in a variety of systems, have indicated the causative role of free radicals and other oxygen-derived active species in PQ+2 toxicity, this question is yet unresolved in the case of MPP+. In this study we have used the E. coli model and have demonstrated that MPP+ is toxic to bacterial cells in a dose and time dependent modes. Additionally, it is shown that only in the presence of molecular oxygen, bacterial inactivation occurred. The protective effects of the chemical scavenger--mannitol--and of histidine are presented. These results are in complete accord with a free radical mechanism for MPP+ toxicity.

1-Methyl-4-phenylpyridinium↗
PubMed1990

[Congenital diaphragmatic hernia presenting after the neonatal period].

Congenital diaphragmatic hernia (Bochdalek) is a congenital malformation usually presenting early after birth with a mortality of 50-70%. It is rarely diagnosed after the neonatal period, when the prognosis is considered favorable. We operated on 11 children past the neonatal period, ranging from 6 months to 5.5 years of age. 9 had presented with respiratory symptoms and were operated on semi-electively with excellent results. 2, operated on for strangulation of bowel incarcerated in the hernia, eventually died (aged 7 months and 1 year, respectively). Early diagnosis is important, as early surgery is recommended, even in those without symptoms.

Child, Preschool↗
PubMed1990

Long-term evaluation of a new selectively biodegradable vascular graft coated with polyethylene oxide-polylactic acid for right ventricular conduit. An experimental study.

Low-porosity woven Dacron grafts have been used extensively as an extracardiac conduit in the surgical treatment of congenital and acquired heart diseases involving total heparinization. Caution is still warranted in their use, however, because of long-term complications, including calcification and development of obstructive fibrous peel. In contrast, high-porosity grafts offer much better tissue anchorage and healing but cannot be used under heparinization. We have developed a compound vascular prosthesis in which a knitted Dacron graft is coated with a polymeric biodegradable sealant. Polyethylene oxide-polylactic acid-segmented copolymers comprised the degradable component of the graft. In vitro studies showed that the coated prosthesis exhibited a highly flexible elastomer-like mechanical response. The prostheses were completely watertight, and significant degradation started after 1 week, with absorption completed after 3 weeks. Seven woven and six knitted polyethylene oxide-polylactic acid-coated Dacron grafts used as extracordiac conduits (16 mm), connecting the right ventricle and the pulmonary artery were implanted in dogs. The dogs were killed after 12 to 18 months, and the results are reported. Scanning electron microscopy examination showed peel detachment and nonhomogenous intimal surface with fenestrations in the woven graft group, but complete healing and incorporation of the pseudointima with homogenous, thin lining of the luminal surface in the polyethylene oxide-polylactic acid-coated group. Histologic studies indicated much superior healing and anchorage of the periprosthetic tissue and the pseudointima in the polyethylene oxide-polylactic acid-coated grafts. The biodegradable polymer was fully degraded and exhibited a complete incorporation of the compound vascular prosthesis. This study indicates the superior healing properties of these selectively biodegradable grafts, which might increase long-term patency and decrease complications of right ventricular conduits.

Animals↗
PubMed1989

[Physiological responses to heat and effort and complaints of hyperperspiration].

The sensation of hyperperspiration is a common complaint in hot, humid climates. 54 men and 20 women, 18-47 years old, who had this complaint and 27 male control subjects were examined at rest and after 1 hour of mild exercise (40W) under conditions of heat stress (37 degrees C, 50% relative humidity). During exposure to heat rectal and skin temperatures and heart rate were measured every 15 min. Sweat rate was calculated for the entire period of exposure and sweat gland density was measured at 0, 60 and 120 min. Only insignificant deviations from baseline values were noted at rest. During exercise the sweat rate of the men with the complaint was within normal limits and similar to that of the control men (285 +/- 75 ml/m2 vs 272 +/- 48). Matching for age and V02 max revealed no significant differences in physiological responses of men with and those without the complaint. Women with the complaint lost 25-30% less fluid (226 +/- 67 ml/m2) and their concentrations of active sweat glands were lower than in either of the male groups. 2 men and 1 woman with the complaint and 1 control lost 400-425 ml/m2 during exercise, the upper limit of normal. Only 1 subject showed hyperperspiration (855 ml/m2) during the test. All physiological parameters examined in these 5 subjects were within normal limits. It is concluded that the complaint of hyperperspiration in our self-selected group is basically a subjective feeling and has no pathological basis. None of the subjects was heat intolerant.

Adult↗