Haile T. Debas

The role of amniotic fluid in fetal nutrition.

The contribution of amniotic fluid to fetal growth and gastrointestinal tract development was studied in a rabbit model. In the fetal rabbit, at 23 days gestation, 3 conditions were surgically produced: (1) prevention of swallowing of amniotic fluid by esophageal ligation (n = 8); (2) esophageal ligation but insertion of an esophageal cannula distally to allow continuous infusion into the stomach of bovine amniotic fluid to mimic fetal swallowing (n = 7); and (3) sham operation (n = 7). Fetuses were delivered by Caesarean section at 28 days gestation. Esophageal ligation resulted in significant reductions of birth weight and crown-rump length and a trend to decreased liver weight when compared to sham operated controls. Additionally, marked reductions in gastric and intestinal tissue weight and gastric acidity were found following esophageal ligation. These reductions in both somatic and gastrointestinal tract growth and gastric function were reversed by infusion of amniotic fluid intragastrically. We conclude that amniotic fluid provides 10% to 14% of the nutritional requirements of the normal fetus, and that amniotic fluid contains a potent and as yet undefined gastrointestinal tract trophic factor.

Clinical and functional characterization of high gastroesophageal reflux

In 70 consecutive patients with symptoms of gastroesophageal reflux (GER), we studied lower esophageal sphincter (LES) and upper esophageal sphincter (UES) pressures, esophageal peristalsis, and esophageal acid exposure 5 and 20 cm above the LES. Based on the percentage of time the pH was below 4 in the proximal esophagus, the patients were divided into 2 groups: (1) group A, less than 3%, 48 patients; (2) group B, greater than 3%, 22 patients. LES was weaker (13.5 +/- 6.0 mm Hg in group A versus 7.8 +/- 4.6 mm Hg in group B) and shorter (2.2 +/- 0.7 cm in group A versus 1.5 +/- 0.5 cm in group B) in group B patients. Group B patients also had lower amplitude of peristalsis in the proximal (59.2 +/- 17.6 mm Hg in group A versus 42.4 +/- 18 mm Hg in group B) and distal esophagus (89.7 +/- 25.2 mm Hg in group A versus 54.7 +/- 27.9 mm Hg in group B) and lower UES pressures (73.7 +/- 30.7 mm Hg in group A versus 54.7 +/- 29.3 mm Hg in group B). Forty-one percent of group B patients had pulmonary aspiration, whereas only 2% of the patients in group A experienced pulmonary aspiration. These data show that, in a subgroup of patients with symptoms of GER, the upper esophagus is exposed to acid for more than 3% of the time. Patients with high GER differ clinically and pathophysiologically from those in whom reflux is limited to the distal part of the esophagus: those with high GER have a panesophageal motor dysfunction and a high risk of aspiration.

Surgical education in the United States: portents for change.

The United States surgical residency and fellowship education programs have been the envy of much of the rest of the world—structured, focused, monitored, evaluated, and credentialed. Recently, multiple professional, personal, and societal changes have brought pressure to bear on the system, forcing the prospect of major change. Because change is painful, there is a desire to focus on past accomplishments to justify the status quo. However, the winds of influence are such that change is inevitable for the continued supremacy of the postgraduate surgical education system in the United States. We hypothesized that we could define the factors necessitating pressure for change if we looked at the constituency that the education system was designed to serve. We believe that an examination of those expectations would help identify where change is needed. We hoped to sustain a national dialogue on this issue so crucial to our future.

Disease Control Priorities, Third Edition: Volume 1. Essential Surgery

Essential Surgery is the first volume in the Disease Control Priorities, third edition (DCP3) series. DCP3 endeavors to inform program design and resource allocation at the global and country levels by providing a comprehensive review of the effectiveness, cost, and cost-effectiveness of priority health interventions. The volume presents data on the surgical burden of disease, disability, congenital anomalies, and trauma, along with health impact and economic analyses of procedures, platforms, and packages to improve care in settings with severe budget limitations. Essential Surgery identifies 44 surgical procedures that meet the following criteria: they address substantial needs, are cost effective, and are feasible to implement in low- and middle-income countries. If made universally available, the provision of these 44 procedures would avert 1.5 million deaths a year and rank among the most cost effective of all health interventions. Existing health care delivery structures can be leveraged to provide affordable and quality care, with first-level hospitals capable of delivering the majority of procedures, while addressing substantial disparities in safety. Existing infrastructure can also expand access to surgery by implementing measures such as task sharing, which has been shown to be safe and effective while countries build workforce capacity. Nearly ten years after the second iteration of Disease Control Priorities was released, increased attention to the importance of health systems in providing access to quality care is once again reshaping the global health landscape. Low- and middle-income countries are continuing to set priorities for funding and are making decisions across an increasingly complex set of policy and intervention choices with a greater appreciation for the value of program and economic evaluations. By reviewing the large burden of surgical disorders, the cost-effectiveness of surgical procedures, and the strong public demand for surgical services, Essential Surgery makes a compelling case for improving global access to surgical care.

The effect of somatostatin on experimental intestinal obstruction.

The effect of somatostatin (SS-14) was tested in an anesthetized rabbit model of closed-loop ileal obstruction. Experimental groups included (1) immediate treatment (N = 6) receiving SS-14 2,000 pmol X kg-1 X h-1 intravenously (I.V.) beginning at the time of ileal obstruction, (2) delayed treatment (N = 5) receiving SS-14 beginning 6 hours following ileal obstruction, and (3) control (N = 6) receiving only hydration. After 24 hours, all rabbits were killed. Significantly decreased intestinal luminal volume and sodium and potassium output was observed with both immediate and delayed SS-14 treatment when compared to control. Additionally, the gross and microscopic pathologic features of intestinal distension, inflammation, and necrosis seen in control rabbits were absent in rabbits treated with SS-14. The known broad spectrum of physiologic activity of SS-14 on the gastrointestinal tract appeared beneficial in this rabbit model of intestinal obstruction.

Research: a vital component of optimal patient care in the United States.

In 1975, a trend began in which applications of MDs to the National Institutes of Health for research funding became less successful than applications from PhDs or MD/PhDs. MD/PhDs were the most successful applicants. Concomitantly, proposals for clinical research were less successful than nonclinical proposals. Since 1975, surgeons have fared disproportionately worse than researchers in other clinical disciplines in obtaining funding from the National Institutes of Health. Despite the efforts of surgical organizations, surgeons continue to fall farther behind in getting National Institutes of Health support for research. The most likely cause of this problem is that the surgical profession has failed to develop and sustain an adequate research workforce.

Corticotropin-releasing factor inhibits gastric emptying in dogs: Studies on its mechanism of action

The effects of corticotropin-releasing factor (CRF) on gastric emptying of a saline solution was further investigated in six dogs prepared with gastric fistulas and chronic cerebroventricular guides and in four other dogs with chronic gastric fistulas and pancreatic (Herrera) cannulas. Intravenous infusion of CRF significantly inhibited gastric emptying whereas intracerebroventricular injection of CRF had no effect. Pharmacologic blockade of beta-adrenergic system by propranolol did not modify intravenous CRF induced delay in gastric emptying. Intravenous CRF did not influence basal pancreatic secretion whereas secretin infused stimulated bicarbonate secretion. These results indicate that intravenous but not intracerebroventricular administration of CRF inhibited gastric emptying of a saline solution in dogs. The inhibitory effect of intravenous CRF on gastric emptying is not mediated by the beta-adrenergic nervous system, and not secondary to the release of other peptides that affect both pancreatic secretion and gastric emptying such as cholecystokinin and peptide YY.

A new intraoperative test for completeness of vagotomy: The PCP-GABA (Beta-parachlorophenol-gamma-aminobtrtyric acid) test

PCP-GABA, an analogue of the neurotransmitter amino acid, GABA, is as effective a stimulant of vagal centers and acid secretion as sham feeding. Insulin hypoglycemia, a test hitherto widely used for the cephalic phase, is unsafe and nonspecific because it also stimulates catecholamine release which affects gastrin secretion. PCP-GABA, unlike insulin, causes no tachycardia or hypoglycemia; however, the major advantage of PCP-GABA is that it can be used safely intraoperatively to assess completeness of vagotomy. Its muscle relaxant action is an additional advantage in this regard. As an intraoperative test, PCP-GABA is given intravenously shortly after induction of anesthesia to stimulate acid secretion and to reduce gastric mucosal pH, which is measured by an intraluminal combination electrode. The electrode can be moved around through the intact gastric wall to take measurements from multiple sites. When vagotomy is complete, gastric mucosal pH increases to over 6. This test works well in the dog. We hope to assess its clinical use in the near future.

Use of secretin in the roentgenologic and biochemical diagnosis of duodenal gastrinoma

The use of secretin in the biochemical and roentgenologic diagnoses of a duodenal gastrinoma has been described. Preoperatively, the secretin test indicated that a gastrinoma and not a retained antrum was the cause of hypergastrinemia in a patient who had previously undergone Billroth II gastrectomy. Intravenous infusion of secretin during selective angiography resulted in greatly enhanced visualization of the tumor which allowed it to be localized to the duodenal stump. Several months postoperatively, the secretin test result had become negative, which presumably suggested that the tumor had been excised completely. Our experience has revealed that intravenous secretin might improve the diagnostic usefulness of selective angiography.

Proximal gastric vagotomy interferes with a fundic inhibitory mechanism

Abstract The mucosa of the proximal stomach contains a powerful inhibitor of acid secretion and gastrin release. The release of this inhibitor is dependent on intact vagal innervation of the proximal stomach. Thus, proximal gastric vagotomy interferes with the release of the inhibitor. After proximal gastric vagotomy for peptic ulcer, recurrence rates increase over time. In addition, there is some recovery of acid secretion. Although nerve regeneration or sprouting has been suggested as the possible explanation for these events, we propose that interference with the inhibitory mechanism of the proximal stomach may be another possible explanation for the increasing ulcer recurrence rates after proximal gastric vagotomy. At present, this is only a hypothesis and is suggested only by indirect evidence. Direct testing of the hypothesis will require complete purification of the inhibitor and the development of a specific radioimmunoassay.