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Biomedical subjects

C T Bombeck

Publications and source records attributed to C T Bombeck.

At least 55 records · Page 3Linked to original sources

Effect of acetylcholine and catecholamines on the enterochromaffin-like cells of the stomach.

Small pieces of fundic mucosa from rats were incubated for 15 minutes at 3 degrees C. in tissue culture medium, and the effects of acetylcholine, epinephrine and norepinephrine on the enterochromaffin-like cell were studied by electron microscopy with a morphometric study of the secretory granules. The addition of acetylcholine and norepinephrine did not cause significant changes in the secretory granules of the cell, while the addition of epinephrine caused a significant increase in the volume density of the secretory granules. This increase was associated with a significant decrease in electron opaque components within the secretory granules of the cell. The results suggest that the activity of the cells in rats is under direct adrenomedullary influence.

Acetylcholine↗

Complete vagotomy. The evolution of an effective technique.

In the 36 years since the reintroduction of truncal vagotomy for the treatment of duodenal ulcer, recurrent ulcer at a rate of between 7% and 12% has become accepted as the most serious long-term postoperative complication. Although techniques for performance of complete vagotomy have been described, many of these principles of technique have been either forgotten or discarded. The new techniques of vagotomy, that is, selective and highly selective vagotomy, have realerted us to the necessity of performing a careful and wide anatomic dissection of all periesophageal tissue of the esophagogastric junction.

Duodenal Ulcer↗

Non-gastrin, intestinal-phase secretion. Experimental confirmation in the dog.

Four mongrel dogs were prepared with a Heidenhain pouch, a gastric fistula, and a 90-cm-long Thiry-Vella loop. After recovery, dose-response curves were obtained with different doses of pentagastrin, and the maximal acid output was determined. The jejunal loop was perfused for 3 h with either 5% liver extract or with 0.15 M NaCl at a rate of 114 ml/h. To verify that the stomach could release gastrin and that the assay could detect that change, antral perfusion with liver extract was performed. Serum gastrin levels and acid output were measured every 30 min. Perfusion of the jejunal loop with liver extract resulted in a significant increase in acid output from the Heidenhain pouch and the gastric fistula, whereas perfusion with saline solution failed to show any changes. The magnitude of acid response from the Heidenhain pouch and gastric fistula was 11% and 18%, respectively, as compared with maximal pentagastrin stimulation. The serum gastrin levels remained unchanged during both liver extract and saline perfusion of the jejunal loop, in contrast to the marked increase in serum gastrin level after antral perfusion. The results confirm the existence of the intestinal phase of gastric acid stimulation in dogs as an entity and show that the magnitude of this phase is significantly lower than has been suggested by results of earlier studies. Furthermore, the results suggest that the intestinal phase of gastric secretion in dogs is most probably elicited through a humoral agent other than gastrin.

Animals↗

Relationship between cimetidine plasma levels and gastric acidity in acutely ill patients.

The relationship between cimetidine plasma levels and gastric acidity was studied in acutely ill patients. Patients in surgical intensive care for stress ulcer who were being managed with nasogastric suction were studied. Nine patients (Group 1) received 300 mg of intravenous cimetidine over 30 minutes every six hours. Titratable acidity and pH of gastric aspirates and plasma cimetidine levels were measured at peak (1.5--2.5 hours) and trough (5--6 hours) times following cimetidine administration, in Group 1. Titratable acidity and pH were measured for nine Group 2 patients (control) who did not receive cimetidine. In Group 1, mean gastric acid output was significantly lower (p less than 0.05) and mean pH was significantly higher (p less than 0.005) than in Group 2. In Group 1, plasma cimetidine concentration correlated poorly with gastric pH and gastric acid output (r = 0.21). The study indicates that the correlation between plasma cimetidine levels and gastric acid secretion is poor, but that the cimetidine dosage used suppressed acid output during the entire dosing interval.

Adult↗

The lower esophageal sphincter: mechanisms of opening and closure.

Patients with and without gastroesophageal reflux cannot be separated on the basis of lower esophageal sphincter (LES) miximal pressure alone, suggesting that more than this single factor is involved in normal closure of the LES. The physics of the closure mechanism was investigated in vivo in one and in vitro in two models. In anesthetized dogs the gastric and esophageal pressures were measured during gastric infusion while the LES gave way to reflux. In vitro sphincters were simulated on flaccid rubber tubes and excised canine gastroesophageal specimens. In model I the sphincter was simulated by mounting the specimen in a chamber and applying external pressure. In model II a ligature with graded tension was applied around the specimen. Station pullback manometry and pressure variations during constant flow perfusion were studied for these sphincter models. An opening pressure and a closing pressure for the LES were defined. The wall tension of the stomach as a force contributing to sphincter opening was recognized, introducing the degree of gastric distension as an important factor in sphincter function. The sealing property of the mucosa was estimated. The length of the sphincter was suggested to contribute to sphincter competence by decreasing the importance of gastric wall tension in sphincter opening and by improving the mucosal seal.

Animals↗

Effects of celiacectomy and stellatectomy on gastric mucosal innervation and acid secretion in the dog.

The effect of surgical excision of the celiac and superior mesenteric ganglia and the stellate ganglia, respectively, on gastric acid secretion and adrenergic innervation of gastric mucosa was studied in five dogs. After removal of the abdominal ganglia, there was a significant increase in acid secretion while there was a marked decrease in the number of adrenergic nerve terminals in the mucosa. When, addition, the stellate ganglia were excised, acid secretion increased slightly in two dogs, while little change in mucosal innervation was noted. These data suggest that the adrenergic innervation of the stomach has an inhibitory role in the control of acid secretion in the dog. Vagal adrenergic nerve fibers seem to be of limited importance in gastric acid production.

Adrenergic Fibers↗

Origin of the adrenergic nerve fibers in the subdiaphragmatic vagus in the dog.

The vagi at the subdiaphragmatic level were studied by the Hillarp-Falck technic in combination with a nerve crush procedure in three normal dogs and in eight dogs that had undergone previous surgical excision of the superior cervical ganglion and/or the stellate ganglia. Unilateral ganglionectomies were performed so that the contralateral vagus served as a control. Based on these results, it is concluded that: (1) the subdiaphragmatic canine vagus contains numerous adrenergic nerve fibers; (2) the main portion of these vagal adrenergic fibers arises from the stellate ganglia; and (3) removal of both the stellate and the superior cervical ganglia results in nearly complete adrenergic denervation of the abdominal vagus.

Adrenergic Fibers↗

Gastric acid secretion after chemical sympathectomy.

Adrenergic nerve terminals in several organs are selectively destroyed by 6-hydroxydopamine (6-OHDA) resulting in a chemical sympathectomy that is reversible. In this study the acute and chronic effects of 6-OHDA on gastric mucosa and acid secretion were evaluated. Four dogs were given 6-OHDA (40 mg/kg, intravenously). Gastric biopsies were taken before treatment and biweekly thereafter and were analyzed by fluorescence microscopy (Hillarp-Falck). Degeneration of adrenergic nerve terminals in the mucosa was complete at 1 week. Early regeneration was noted at 3 weeks and appeared to be complete at 9 weeks. In another group of seven dogs with a gastric fistula, dose-response curves to pnetagastrin (PPG, 0 to 5 microgram/kg/hr) were determined. Then 6-OHDA (40 mg/kg) was given to these dogs and secretory studies were repeated weekly thereafter for 8 weeks. After 6-OHDA administration, acid secretion increased in response to submaximal doses of PPG, whereas maximal secretion was unchanged. The peak increase occurred the second week; thereafter secretion gradually returned to control values. We conclude that chemical sympathectomy (6-OHDA) increases gastric acid secretion in response to submaximal PPG stimulation. This increase correlates well with the 6-OHDA--induced degeneration of adrenergic terminals in the mucosa. These data suggest that the adrenergic innervation of the stomach has an inhibitory effect on the control of acid secretion in the dog.

Animals↗

Critical operative management of small bowel obstruction.

The records of 238 patients with the diagnosis of small bowel obstruction at the University of Illinois Hospital from 1967 through the spring of 1976 were reviewed. Mortality, intra-operative management, and clinical findings were evaluated. Previous reports list a mortality of gangrenous small bowel obstruction, secondary to hernia and/or adhesions, as greater than 20%, although in this series, the mortality was 4.5% in patients with gangrenous small bowel obstruction. The present data reveal a 60% incidence of wound infection in patients in whom an enterotomy (iatrogenic, decompressive or resective) was made and the subcutaneous tissue and skin closed, and it is therefore recommended that the wound be left open in these situations. Although a variety of individual clinical findings have been advocated as diagnostic aids in patients with small bowel obstruction, this review suggests that attention to a combination of "classic" findings, i.e., leukocytosis, fever, tachycardia and localized tenderness, portends a situation in which conservative observation is safe--namely, the absence of all four findings. The presence of any one or more of these findings mandates early operative intervention.

Chicago↗

H2 receptor antagonists.

The uses of the histamine H2 receptor antagonists (H2 antagonists) in the management of peptic ulcer disease and the Zollinger-Ellison syndrome are reviewed. Drugs included in the discussion are burimamide, metiamide and cimetidine. The secretion and the pharmacology of the H2 antagonists are described. A discussion of the clinical use of the H2 receptor antagonists in the treatment of gastric hyperacidity and hypersecretory states, and the side effects encountered is presented. Cimetidine is effective in the treatment of duodenal ulcer, and its use appears promising in Zollinger-Ellison syndrome and gastric ulceration.

Cimetidine↗

Role of the sympathetic nervous system in peptic ulcer production in rats.

The role of the sympathetic nervous system in gastric acid secretion and in experimental duodenal ulceration (cysteamine induced) was studied in rats. The animals were divided randomly into seven groups: (1) control, (2) sham-operated, (3) surgical sympathectomy, (4) chemical sympathectomy (6-HODA), (5) vagotomy, (6) surgical sympathectomy plus vagotomy, and (7) chemical sympathectomy plus vagotomy. Results on gastric acid secretion were expressed as gastric acid output (GAO = micronEq of acid secretion in 1 hour). The means in the control and sham groups were 447.83 +/- 26.67 GAO and 399 +/- 36.4 GAO, respectively. The means in the sympathectomized rats (surgically = 562 +/- 27.21 GAO and chemically = 648.66 +/- 46.53 GAO) were higher (P less than 0.01) than those of the control and sham groups. In the vagotomized group the mean was 156.6 +/- 17.64 GAO, lower than those of the control and sham groups (P less than 0.001). The incidence of ulceration was 47.5% and 46% in the control and sham groups, respectively. Both the sympathectomized groups (surgically, 73%; chemically, 77%), had a significantly elevated incidence of ulceration as compared with the controls (P less than 0.01). The vagotomized group had a 14% incidence of ulceration. These results clearly indicate that sympathectomy has a definite effect on gastric acid secretion and on the incidence of experimental peptic ulceration in rats.

Adrenergic Fibers↗

Adenyl cyclase and cyclic AMP (cAMP) in acute experimental pancreatitis.

The level of adenosine 3':5'-cyclic monophosphate (cAMP) and the activity of adenyl cyclase were studied in the pancreas under normal conditions and during acute hemorrhagic pancreatitis induced by intraductal injection of fresh trypsin-bile-blood mixture. In addition, the adenyl cyclase was localized histochemically in the pancreas. Basal cAMP concentration and adenyl cyclase activity were 0.88 +/- 0.11 pmoles/mg wet tissue and 3.39 +/- 0.21 pmoles/mg protein/min, respectively. The acute pancreatitis drastically reduced the adenyl cyclase activity at 15 minutes to 1.66 +/- 0.54 pmoles/mg protein/min, and totally suppressed adenyl cyclase activity at 30 minutes after the onset of pancreatitis without affecting cAMP levels. The presence of sodium fluoride in the incubation medium prolonged the enzyme activity up to 45 minutes. The progressive disappearance of adenyl cyclase activity presumably resulted from the destruction of cellular integrity caused by autodigestion by the active proteolytic enzymes released during pancreatitis.

Acute Disease↗

Cyclic Amp and the release of antral gastrin.

The isolated, vagally innervated antral pouches in anesthetized dogs were irrigated with 095% acetylcholine chloride (Ach) or a 0.4 M mixture of non-essential amino acids (AA), or distended at 30 cm H2O pressure. In addition,2-deoxy-D-glucose (2-DG) was administered intravenously. Significant increases in antral venous gastrin, caused by gastrin releasers, were associated with a significant rise in cAMP content in the antral mucosa. Acidification of the antrum with simultaneous administration of 2-DG, and acidified AA abolished gastrin release, and significantly reduced mucosal cAMP. Acidified Ach and distension of the antrum with 0.1 N HC1 supressed gastrin levels without significantly changing the mucosal cAMP content. Since the augmented gastrin release was accompanied by an increased mucosal cAMP, the results suggest that cAMP participates in the action of gastrin secretagogues.

Acetylcholine↗

Continuous positive airway pressure in the prophylaxis of the adult respiratory distress syndrome.

After an operation upon the abdomen, certain patients have a high risk of developing acute respiratory failure or the adult respiratory distress syndrome. These patients at high risk have been mechanically ventilated during the postoperative period in an attempt to prevent the onset of respiratory insufficiency. As a method of prophylaxis, continuous positive airway pressure has the advantages of increasing the functional residual capacity with minimal effects on the cardiac output, low potential for barotrauma and simplicity of equipment. Alternate patients at risk following an operation on the upper part of the abdomen were placed on 8 centimeters of water continuous positive airway pressure for the first 24 hours postoperatively. Fifty-six controls and 56 patients receiving continuous positive airway pressure were studied. In ten controls, adult respiratory distress syndrome developed, and three died in respiratory failure. Only one of the group receiving continuous positive airway pressure met standard criteria for the diagnosis of adult respiratory distress syndrome. In addition, in 25 patients serving as controls, respiratory complications other than adult respiratory distress syndrome developed compared with the development in only 11 receiving continuous positive airway pressure9

Abdomen↗