PubMed Health⌕ Search

Biomedical subjects

L M Nyhus

Publications and source records attributed to L M Nyhus.

At least 91 records · Page 5Linked to original sources
PubMed1983

A new concept in the surgical treatment of gastroesophageal reflux.

Surgical treatment of gastroesophageal reflux has been thought to depend on the construction of a valve mechanism at the gastroesophageal junction (GEJ). Recently, a silicone prosthesis that does not construct a valve has been introduced, and in preliminary studies in the human, shown to be effective in the treatment of reflux. A precise mode of action has not been demonstrated for the prosthesis. This study was undertaken to investigate the mechanics of the prosthesis and determine its effectiveness in an animal model. Six canine gastroesophageal specimens were excised and the lower esophageal sphincter (LES) simulated by a rubber band placed around the GEJ at a tension calibrated to give 25 mmHg "sphincter" pressure. Circumferential silk ligatures of varying length were then placed on the stomach 3.0 cm distal to the GEJ. With no ligature, the LES opening pressure (LESOP) was 8.0 mmHg, varying to 17.0 mmHg with an 8.0 cm ligature. Further, 24 adult mongrel dogs were randomly divided into four equal groups: controls, circular myomectomy of the LES alone, myomectomy combined with fundoplication, and myomectomy combined with implantation of the silicone antireflux prosthesis. Evaluation included manometry, endoscopy, and histology. Although only the normal sphincter and fundoplication responded physiologically, the prosthesis was just as effective in preventing reflux, as evidenced by reducing acid exposure time of myomectomized dogs from 35.4% to 1.8%, and by preventing endoscopic esophagitis. It was concluded that the silicone antireflux prosthesis acts in the same fashion as the ligature in the model, by interrupting distraction of the LES by gastric wall tension. This concept is an effective method for raising LESOP, treating experimental gastroesophageal reflux, and eliminating the sequelae of reflux. Long-term evaluations of the prosthesis are required.

Animals↗
PubMed1983

Comparison of cAMP system in parietal cells from rat and guinea pig.

Adenylyl cyclase activity, cAMP content, and activation of cAMP-dependent protein kinase were measured in rat and guinea pig parietal cells isolated by the same procedure. Incubation of parietal cells with histamine resulted in aminopyrine uptake, stimulation of adenylyl cyclase activity, accumulation of intracellular cAMP, and activation of cAMP-dependent protein kinase. In addition, aminopyrine uptake and the cAMP system were stimulated in rat cells by epinephrine, whereas guinea pig cells were unresponsive to epinephrine. It is suggested that there may be differences between the two species with regard to receptors on the parietal cells.

Animals↗
PubMed1982

Emergency transumbilical embolization of bleeding esophageal varices.

Eight patients had major hemorrhage from esophageal varices; in seven, one or two embolizations of the coronary and short gastric veins resulted in cessation of hemorrhage. This procedure can be used in patients with massive ascites, severe coagulopathy, or profound liver failure, as the access route through the dilated umbilical vein can be reached via a supraumbilical incision done with the patient under local anesthesia. All patients died; two deaths were attributable to complications of the procedure, the other six to the severity of the cirrhosis. Sclerotherapy may be combined with coronary vein embolization, but the risk of esophageal perforation may be greater than with sclerotherapy alone.

Adult↗
PubMed1982

Ultrasonic assistance during surgery for pancreatic inflammatory disease.

Real-time B-mode ultrasound scanning was used during 35 operations for inflammatory disease of the pancreas. In 21, ultrasonography was considered helpful in operative management of pancreatic pseudocysts, abscesses, and chronic pancreatitis. Assistance consisted of establishing a diagnosis not made during preoperative testing, more precisely localizing pancreatic abnormalities, and excluding the presence of pseudocyst, abscess cavities, and dilated ducts. Operative ultrasound is a safe and simple technique that may reduce the use of tissue dissection, contrast material injections, and radiation.

Abscess↗
PubMed1982

Detection of pancreatic tumors by ultrasound during surgery.

Real-time B-mode ultrasonic scanning was performed during 14 operations for pancreatic tumors. All operations were for adenocarcinoma, except in one patient with a Zollinger-Ellison tumor. The ultrasonic tissue appearance of pancreatic carcinoma was not specific. However, ultrasonic signs of pancreatic duct dilation, striction or invasion of the superior mesenteric veins, and common bile duct involvement may help to establish the diagnosis of malignancy. A triad of ultrasound signs indicative of malignant obstruction of the common bile duct consisted of (1) dilation, (2) absence of biliary stones, and (3) a distinctive termination pattern of the duct. Operative ultrasound was used to guide a biopsy needle to obtain pancreatic tissue samples. The Zollinger-Ellison tumor of the pancreas produced a sonolucent appearance that clearly distinguished it from the surrounding tissue.

Adenocarcinoma↗
PubMed1982

Effect of 3-isobutyl-1-methylxanthine on histamine-stimulated gastric secretion in dogs.

The effect of IMX on histamine-stimulated gastric secretion has been studied in dogs equipped with gastric cannulas. After determining the histamine dose response, IMX, histamine, and IMX plus histamine were given by a constant intravenous infusion for 3 h, and acid was collected at 15-min intervals. In a separate series of experiments a single dose of 100 mg of db-cAMP was given 1 h after initiation of infusion of IMX, histamine, and histamine plus IMX. Results show that IMX, a potent inhibitor of phosphodiesterase, is a weak stimulant of acid secretion, and augments histamine-stimulated secretion. However, during stimulated acid secretion, there were no significant changes in tissue cAMP levels, Administration of exogenous dib-cAMP did not produce any significant changes in acid secretion in dogs, but did contribute to elevated cAMP levels.

1-Methyl-3-isobutylxanthine↗
PubMed1982

Neurohumoral observations and the gastrointestinal tract.

Vagal interrelationships with the gastric antrum have been studied in depth. A special experimental model, antroneurolysis, demonstrated that the function of the gastric mucosa is maintained after removal of central neural control, that is, vagotomy. A series of experiments are reported which demonstrate the importance of the sympathetic nervous system in the local control of gastrointestinal function. The concept of local neural control of the endocrine and secretory function of the epithelial cells of the intestinal mucosa (internal brain) is proposed.

Adrenergic Fibers↗
PubMed1982

Surgeon-endoscopists and the assessment of postoperative patients.

There is a definite need for surgeons with an interest in gastrointestinal problems to develop and maintain expertise in gut endoscopy. In this article we emphasize the interpretation of symptoms in postoperative patients as a focal point, although other illustrations might be cited. While stressing the role of surgeons in this respect, it is essential to underscore the complementary roles of surgeons and physicians, and to emphasize that both disciplines' points of view are needed to determine the source of patients' complaints. The special awareness that a surgeon brings to the analysis of these postoperative problems results from a knowledge of postoperative patients in general, supplemented by an awareness of technical factors that might either influence the operation's success or explain a new symptom occurring in the postoperative period.

Duodenal Ulcer↗
PubMed1982

Ultrastructural observations in the rat ileal mucosa of possible epithelial "taste cells" and submucosal sensory neurons.

Electronmicroscopical studies of the rat ileum have demonstrated the presence of submucosal neuronlike cells located just under the basal lamina of intestinal crypts. These cells had dendrite-like processes and frequently made contacts with adjacent submucosal nerve terminals. Furthermore, within the mucosa epithelial "clear' cells with apical cytoplasmic processes into the gut lumen and basal cytoplasmic processes extending underneath adjacent epithelial cells were demonstrated. The "clear' cells were devoid of secretory granules, as e.g. endocrine cells, and had a morphological resemblance to taste cells. Occasionally the "clear' cells made contacts with submucosal nerve terminals. The possibility that the "clear' cells and submucosal neuronlike cells represent a receptive function within the intestine is discussed.

Animals↗
PubMed1981

Identification of a parathyroid adenoma by operative ultrasonography.

During surgery, real-time ultrasound scanning accurately localized a parathyroid adenoma posterior to be the superior pole of the right thyroid lobe. This was made feasible because of the ultrasound features of parathyroid tissue and current developments in ultrasound instrumentation.

Adenoma↗
PubMed1981

Ultrasonic imaging during biliary and pancreatic surgery.

Real-time ultrasound scanning was used during operations on the biliary tract and pancreas. The principal application in biliary surgery was to evaluate the common bile duct for presence of calculi. Our initial experience indicates that operative ultrasonography compares favorably with operative cholangiography. In pancreatic operations, ultrasound has been helpful in the management of pseudocysts and chronic pancreatitis. For pseudocysts, ultrasonography has indicated cyst wall thickness and the presence of adjacent anatomic structures. Ultrasound has distinguished the fluid loculations of the pseudocyst from swelling due to inflammatory edema. In surgery for chronic pancreatitis, ultrasonography has revealed the size and location of pancreatic ducts. This information has been useful in helping select sites for internal drainage of pseudocysts and in chronic pancreatitis with ductal dilatation. Operative ultrasonography is a relatively simple procedure which has the potential for providing the surgeon with early information and decreasing the need for dissection and radiographic imaging.

Biliary Tract Diseases↗