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Biomedical subjects

M G Sarr

Publications and source records attributed to M G Sarr.

At least 163 records · Page 9Linked to original sources
PubMed1993

Chronic bile diversion does not alter canine interdigestive myoelectric activity.

Previous studies have suggested that the cyclic entry of bile into the duodenum during fasting regulates interdigestive patterns of motility by releasing the putative regulatory hormone motilin. Our aim was to determine if cyclic secretion of bile into the duodenum regulates interdigestive myoelectric activity and plasma motilin concentrations. Six dogs were prepared with gastric and intestinal serosal electrodes. Myoelectric activity was measured during fasting and after a meal before and after reoperative translocation of the entrance of the bile duct to the mid-jejunum. The characteristics of the migrating myoelectric complex (MMC) and conversion to a postprandial pattern were similar before and after bile duct translocation. The period (112 +/- 5 vs 109 +/- 10 min; mean +/- SEM), migration velocity of phase III through the duodenum (8.9 +/- 1.2 vs 6.8 +/- 0.5 cm/min), and duration of individual phases of the MMC in the stomach, duodenum, and jejunum were not altered significantly (each P > 0.05) by chronic diversion of bile from the duodenum. Plasma motilin concentrations were similar before and after bile duct translocation (P > 0.05), continued to cycle temporally with the MMC, and peak concentrations occurred during phase III and were greater than during phases I and II (P < 0.01). We conclude that the presence of bile in the lumen of the duodenum does not regulate interdigestive myoelectric patterns of the canine upper gut or the cyclic release of motilin.

Animals↗
PubMed1993

Effect of alpha-methylnorepinephrine, an alpha 2-adrenergic agonist, on jejunal absorption in neurally intact conscious dog.

Although alpha 2-adrenergic agonists stimulate absorption in the mammalian small and large intestine in vitro, the possibility of central neural effects have confounded interpretation of in vivo studies. Our aim was to assess the effects of intravenous administration of alpha-methylnorepinephrine (MNE), an alpha 2-adrenergic agonist that does not cross the blood-brain barrier, on net jejunal absorption of water and electrolytes in the neurally intact, conscious dog. Absorption from a 30-cm proximal jejunal segment was studied using a triple-lumen perfusion technique in seven dogs. A warmed, isosmolar, balanced electrolyte solution containing [14C]polyethylene glycol was infused at 5 ml/min. Net jejunal fluxes of water and electrolytes were determined before, during, and after a 1.5-hr infusion of MNE (900 nmol/kg/hr). MNE increased net jejunal water absorption (from 12.9 +/- 1.8 to 22.5 +/- 1.5 microliters/cm/min, P < 0.05). Peripheral alpha 2-adrenergic receptors mediate a net proabsorptive response in the neurally intact canine jejunum in vivo independent of direct central neural effects.

Animals↗
PubMed1993

Nitric oxide mediates inhibitory nerve input in human and canine jejunum.

BACKGROUND: Nitric oxide (NO) may be an inhibitory neurotransmitter in the intestinal muscle. The present study examined its role in human and canine jejunum. METHODS: Mechanical and intracellular electrical activity were recorded simultaneously from the circular muscle layer. RESULTS: In the human jejunum, nerve stimulation inhibited mechanical activity and evoked an inhibitory junction potential that consisted of an initial fast hyperpolarization followed by a late sustained hyperpolarization. NO inhibited mechanical activity and evoked a dose-dependent hyperpolarization that mimicked the late hyperpolarization. In the canine jejunum, nerve stimulation inhibited mechanical activity and evoked an inhibitory junction potential that consisted of only a fast hyperpolarization. NG-Monomethyl-L-arginine and NG-nitro-L-arginine attenuated nerve-mediated inhibition of mechanical activity in both species. However, the effect of the synthase inhibitors on inhibitory junction potentials differed in the two species. In canine jejunum, both inhibitors reduced the amplitude of the initial fast hyperpolarization. In human jejunum, both inhibitors reduced only the late sustained hyperpolarization. CONCLUSIONS: NO mediates neural inhibition in circular muscle of both human and canine jejunum through different mechanisms.

Animals↗
PubMed1993

Spectrum and management of major complications of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy has become the most prevalent method of treating uncomplicated, symptomatic cholelithiasis in the United States and elsewhere. As experience with this procedure grows, certain pitfalls are becoming apparent. Since October 1990, we have treated 22 patients for major injuries incurred during laparoscopic cholecystectomy, including 15 women and 7 men (range: 23 to 85 years). One patient had previous upper abdominal surgery; no other patient had any relative contraindication to laparoscopic surgery. The most frequent site of injury (19 patients) was the extrahepatic biliary tract. There was one fatal duodenal perforation. All but two patients whose injuries went unrecognized at laparoscopy were symptomatic during the immediate postoperative period. The biliary injuries included complete transection of the common hepatic or common bile duct in 10 patients, complete ductal occlusion in 3, a cystic duct stump leak in 2, and a partially retained gallbladder with a contained intraperitoneal bile leak in 2. The site and extent of biliary injuries were delineated with transhepatic or endoscopic retrograde cholangiography. Reconstruction or repair of the biliary tract was accomplished with Roux-en-Y hepaticojejunostomy or cholangiojejunostomy in 11 and 1 patients, respectively, completion cholecystectomy in 2, and temporary transhepatic stenting, primary choledochocholedochostomy, and primary choledochorrhaphy over a T-tube in 1 patient each. One patient with a cystic duct stump leak was managed successfully with endoscopic sphincterotomy, whereas another required operative ligation. Laparoscopic injuries during cholecystectomy can lead to serious morbidity and mortality, thus emphasizing the need for adequate training and credentialing for surgeons and for a heightened clinical awareness of the potential complications, their long-term sequelae, and how to avoid them.

Adult↗
PubMed1993

Normal physiology of small intestinal motility.

The small intestine produces a number of different contractions in various spatial and temporal patterns that promote efficient digestion, absorption, and propulsion of ingested material. The small bowel also serves a protective role through the use of special situation contractions that rapidly propel enteric contents into the stomach or colon, from which they may be expelled. Contractile activity of the small intestine is coordinated by an interplay of myogenic, neural, and chemical controls.

Animals↗
PubMed1993

Gastric acid secretion and vitamin B12 absorption after vertical Roux-en-Y gastric bypass for morbid obesity.

OBJECTIVE: This study sought to determine the basal and peak-stimulated acid secretion from the proximal gastric pouch and its relationship to absorption of free and food-bound vitamin B12 after gastric bypass for morbid obesity. SUMMARY BACKGROUND DATA: Gastric bypass can be performed safely and provides acceptable weight loss, but concerns remain about possible long-term complications such as vitamin B12 malabsorption. The authors hypothesized that by constructing a small pouch of gastric cardia, acid secretion into the pouch would be low, leading to maldigestion of food-bound vitamin B12 with subsequent malabsorption. METHODS: Basal and pentagastrin-stimulated peak acid outputs from the proximal gastric pouch were measured in ten patients after vertical Roux-en-Y gastric bypass using a perfused orogastric tube technique. Absorption of free and food-bound 57Co-vitamin B12 was evaluated separately using 24-hour urinary excretion. RESULTS: Basal (mEq/hr, mean +/- standard error of the mean [SEM]) and peak-stimulated (mEq/30 min) acid secretions from the proximal gastric pouch were markedly decreased compared to those for age- and sex-matched hospital control subjects (0.01 +/- 0.01 vs. 4.97 +/- 0.66 and 0.08 +/- 0.04 vs. 12.11 +/- 1.34, respectively; p < 0.001 for each). While absorption of free vitamin B12 was not statistically different from that of control subjects (11 +/- 2 vs. 15 +/- 2%; p > 0.05), absorption of food-bound vitamin B12 was decreased (0.8 +/- 0.2 vs. 3.7 +/- 0.5%; p < 0.01). CONCLUSIONS: After vertical Roux-en-Y gastric bypass for morbid obesity, acid secretion is virtually absent and food-bound vitamin B12 is maldigested and subsequently malabsorbed. The results of this study suggest that postoperative vitamin B12 supplementation is important and can be achieved with either monthly parenteral vitamin B12 or daily oral crystalline preparations.

Adult↗
PubMed1993

Reoperative bariatric surgery. Lessons learned to improve patient selection and results.

OBJECTIVE: The purpose of this study was to determine the spectrum of presentation, safety, and efficacy of operative bariatric surgery. SUMMARY BACKGROUND DATA: The only lasting therapy for medically complicated clinically severe obesity is bariatric surgery. Several operative approaches have resulted in disappointing long-term weight loss or an unacceptable incidence of complications that require revisionary surgery. METHODS: Sixty-one consecutive patients who underwent reoperative bariatric surgery from 1985 to 1990 were observed prospectively. One, two, or three previous bariatric procedures had been performed in 77%, 18%, and 5% of patients, respectively. Reoperation was required for unsatisfactory weight loss after gastroplasty or gastric bypass (61%), metabolic complications of jejunoileal bypass (23%), or other complications (16%), including stomal obstruction, alkaline- or acid-reflux esophagitis, and anastomotic ulcer. Revisionary procedures included conversion to vertical banded gastroplasty (33% of operations) and vertical Roux-en-Y gastric bypass (52% of operations); partial pancreato-biliary bypass was used selectively in four patients with severe, medically complicated obesity. RESULTS: A single patient died postoperatively of a pulmonary embolus; serious morbidity occurred in 11%. Weight loss (mean +/- SEM) after reoperation for unsuccessful weight loss was greater with gastric bypass than with vertical banded gastroplasty (54 +/- 6% versus 24 +/- 6% of excess body weight). Metabolic complications of jejunoileal bypass were corrected, but 67% of the patients were dissatisfied with their postoperative lifestyle because of changes in eating habits or weight gain (64% of patients). Stomal complications and esophageal reflux symptoms were reversed in all patients. CONCLUSIONS: Reoperative bariatric surgery in selected patients is safe and effective for unsatisfactory weight loss or for complications of previous bariatric procedures. Conversion to gastric bypass provides more effective weight loss than vertical banded gastroplasty.

Adult↗
PubMed1993

Activation of whole cell currents in isolated human jejunal circular smooth muscle cells by carbon monoxide.

Carbon monoxide (CO) is a low molecular weight oxide produced endogenously from fatty acids and heme protein. A physiological role for CO has been suggested for vascular smooth muscle, hemostasis, and olfactory neurons, but direct evidence is lacking. Heme oxygenase, which catalyzes the formation of CO from heme proteins, is present in small intestinal smooth muscle. The effect of 1% CO on whole cell currents in normal human jejunal circular muscle cells was studied with the use of a perforated patch-clamp technique. A 1% CO-containing Krebs solution caused an initial and transient increase in whole cell current in 20 of 22 cells tested (175 +/- 40%, mean +/- SE) and a transient hyperpolarization (15.6 +/- 3.6 mV, mean +/- SE) of the membrane potential. During prolonged recordings, 1% CO evoked ongoing cyclic increases and decreases in the whole cell current. Each current increase was accompanied by a sharp membrane hyperpolarization. These data suggest that CO may modulate whole cell potassium current and membrane potential.

Carbon Monoxide↗
PubMed1993

Potassium current in circular smooth muscle of human jejunum activated by fenamates.

Thirty-eight cells, freshly isolated from circular smooth muscle of normal human jejunum obtained from nine patients undergoing weight-reduction surgery for morbid obesity, were patch clamped using a perforated patch-clamp technique. A highly potassium-selective voltage-dependent outward current was present in all cells. The current was carried by a 220-pS channel that activated near -75 mV and reached unit open probability at about +10 mV. Blockade of the current by quinidine (50 microM) and tetraethylammonium (25 mM) was accompanied by membrane depolarization to 0 to -3 mV, suggesting that this current was the major determinant of the membrane potential. Flufenamic and mefenamic acid at concentrations comparable with blood levels reached when these drugs are used in clinical therapy as nonsteroidal anti-inflammatory agents, activated the potassium outward current and hyperpolarized the membrane potential. The shift in the membrane potential for 250 microM flufenamic acid was -36 +/- 24 (SD) mV. Activation was rapid (seconds) and reversible. It was concluded that normal human jejunal circular smooth muscle cells have a highly potassium-selective outward current, which is the major determinant of the membrane potential and which is activated by fenamates.

4-Aminopyridine↗
PubMed1993

Total pancreatectomy. An objective analysis of its use in pancreatic cancer.

When should total pancreatectomy be utilized in the treatment of adenocarcinoma of the pancreas? The rationale for total pancreatectomy comes from a tendency for pancreatic cancer to be multicentric (approximately 30% of patients), the absence of a pancreaticoenterostomy and its attendant morbidity, and the argument that total pancreatectomy is a better cancer procedure (more complete lymphadenectomy, wider soft tissue resection). In spite of these theoretical advantages, any impact on morbidity, mortality, or ultimately on survival has not been realized. Indeed, with the current operative mortality of pancreatic remnant-preserving resections being less than 5%, with the realization of the metabolic consequences of total pancreatectomy, and with the introduction of adjuvant chemo-radiation therapy, extended lymphadenectomy, and the concept of regional pancreatectomy, justification for total pancreatectomy for cancer of the head of the pancreas is questionable. The current data suggest that total pancreatectomy should be used only in selected individuals.

Carcinoma, Ductal, Breast↗
PubMed1992

Complications following pancreaticoduodenectomy. Current management.

From 1980 to 1989, 279 patients underwent pancreaticoduodenectomy at a single institution with a postoperative mortality of 4%. The aim of this study was to determine incidence, origin, and present management strategy of early complications following this operation. Significant morbidity occurred in 46% of the patients, including delayed gastric emptying (23%), pancreaticojejunal anastomotic leak (17%), intra-abdominal sepsis (10%), biliary-enteric anastomotic leak (9%), gastrointestinal tract bleeding (5%), and intra-abdominal hemorrhage (3%). Complications were associated with advanced age, prolonged operations, and increased operative blood loss. Most complications were managed nonoperatively. Mortality was increased when a reoperation was required, a biliary-enteric leak occurred, or an intra-abdominal abscess developed. Pancreaticoduodenectomy continues to carry a high postoperative morbidity; however, operative mortality is low, and management of complications has been made simpler with more sophisticated, nonoperative therapeutic options.

Abscess↗
PubMed1992

Spontaneous perforating hematoma of the rectum. Report of a case.

Intramural hematomas of the intestine most often occur in the setting of blunt abdominal trauma. However, spontaneous hematomas can occur secondary to either hematologic disorders, or use of anticoagulant therapy. There has been no clearly documented report of a spontaneous rectal hematoma. We describe the novel treatment of a patient with a spontaneous intramural hematoma of the rectum which presented as an abdominal catastrophe.

Adolescent↗
PubMed1992

Efficacy of intraoperative enteroscopy in diagnosis and prevention of recurrent, occult gastrointestinal bleeding.

The role and effectiveness of intraoperative enteroscopy in the evaluation of gastrointestinal (GI) bleeding of obscure origin is not clearly defined. Our aim was to determine if intraoperative enteroscopy is effective in identifying a source, which would lead to therapy and prevent recurrent gastrointestinal hemorrhage. Forty-four patients (median age: 64 years) underwent intraoperative enteroscopy. Median number of preoperative blood transfusions, duration of bleeding (months), and prior hospitalizations for GI hemorrhage were 19, 15, and 2, respectively. Many patients had risk factors associated with bleeding. All had undergone an extensive preoperative evaluation. Intraoperative enteroscopy was completely negative in 13 (30%). A site-specific source was seen in the small bowel in 31 patients (70%); 27 patients had lesions amenable to segmental resection with or without other means of definitive management. Only 6 of 31 patients (19%) had lesions that were actively bleeding. Twenty-three (52%) patients have had recurrent bleeding requiring transfusion (median follow-up: 21 months). Although intraoperative enteroscopy identified specific mucosal abnormalities in 70% of patients, the therapeutic efficacy in preventing recurrent hemorrhage was only 41%. Intraoperative enteroscopy is an effective tool in selected patients with occult GI bleeding and correctly identifies a treatable source and prevents recurrent bleeding in 41% of patients.

Endoscopy, Gastrointestinal↗
PubMed1992

The role of myoneural and luminal continuity in the coordination of canine gastroduodenal patterns of motility.

Our aim was to determine the role of intrinsic myoneural and enteric luminal continuity in the coordination of gastric and duodenal motility patterns. Three groups of dogs were prepared: five dogs with an intact gastrointestinal tract served as a Control group; four dogs had transection and reanastomosis of the duodenum 0.5 cm distal to the pylorus (Pyloric Transection group); and seven dogs had identical proximal duodenal transection, but with oversewing of duodenum and pylorojejunostomy to a Roux-en-Y limb (Roux-en-Y group). In the Control and Pyloric Transection groups, the gastric and intestinal MMCs were similar in appearance, the cycle durations (x +/- SEM) were not different (134 +/- 19 vs 111 +/- 26 min, respectively; P > 0.05), and the times between the start of gastric and duodenal Phase III (gastroduodenal latency) were similar (6 +/- 1 vs 10 +/- 3 min; P > 0.05). In the Roux-en-Y group, MMCs also occurred in six of seven dogs but tended to have a longer cycle duration (176 +/- 19 min) and a more variable gastroduodenal latency (23 +/- 15 min). Plasma motilin concentration, measured only in the Roux-en-Y group, was greater during Phase III in the stomach and duodenum than during Phases I or II (P < 0.05). Feeding inhibited the gastric and duodenal MMCs in all groups, but the duodenal MMC returned earlier in the Roux-en-Y group. The Roux-en-Y jejunal limb exhibited a postprandial pattern in only seven of 14 studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Severe reflux esophagitis after vertical banded gastroplasty for treatment of morbid obesity.

Herein we describe two patients with medically refractory, severe reflux esophagitis after vertical banded gastroplasty for morbid obesity. Neither patient had symptoms of reflux preoperatively. Both patients underwent conversion to a vertical Roux-en-Y gastric bypass, an operation that prevents acid and peptic reflux and maintains a weight-reducing anatomy. Symptoms of gastroesophageal reflux are common (they occur in approximately 38% of patients) after vertical banded gastroplasty has been performed. Patients with unusually severe reflux may require operative management.

Adult↗
PubMed1992

Laparoscopic cholecystectomy: early Mayo Clinic experience.

Prospective data and follow-up information were collected on the initial 200 patients who underwent laparoscopic cholecystectomy at the Mayo Clinic. The operation was completed laparoscopically in all but five patients, who required conversion to laparotomy because of dense scarring or stones in the common bile duct. The median surgical time was 85 minutes. The major postoperative complications were retained stones in the common bile duct (in seven patients), intraperitoneal hemorrhage that necessitated transfusion (in two patients), and intra-abdominal abscess and pulmonary infection (in one patient each). The median hospital stay was 1 day (range, 0 to 8 days), and the median times to full activity and normal employment were 8 days and 12 days, respectively. Laparoscopic cholecystectomy is associated with a low frequency of complications in most patients with symptomatic gallstones and allows a rapid return to normal activity. Currently, laparoscopic cholecystectomy is the treatment of choice for most patients with symptomatic cholelithiasis.

Academic Medical Centers↗