Biomedical subjects

R H Turnage

Publications and source records attributed to R H Turnage.

46 records · Page 3Linked to original sources

PubMed1994

Complement activation by the hydroxyl radical during intestinal reperfusion.

This study examines the hypothesis that hydroxyl radical (OH.) generation during intestinal reperfusion activates the complement system forming the potent chemotaxin C5a. Anesthetized Sprague-Dawley rats underwent 120 min of intestinal ischemia and 60 min of reperfusion (IIR). Complement (C) activation was assessed by measuring total plasma C activity and C5a-related chemotaxis and leukoaggregation. Dimethylthiourea and the iron chelator deferoxamine were utilized to assess the role of the OH. in the activation of C in this model. Sham-operated animals served as controls. Total plasma C activity of animals sustaining IIR was 64% of controls (p < .05). Plasma of animals sustaining IIR induced greater chemotaxis and leukoaggregation than plasma from sham-operated groups (p < .05). Treatment of IIR plasma with anti-C5a antibody ameliorated the enhanced leukoaggregation characteristic of IIR plasma. Pretreatment with dimethylthiorea and deferoxamine prevented reperfusion-induced activation of complement and inhibited the chemotactic activity of plasma from IIR animals. These data are consistent with the hypothesis that IIR activates complement and that the OH. generated during reperfusion may be one mechanism by which C is activated in this injury model.

Animals↗

PubMed1994

Pulmonary microvascular injury following intestinal reperfusion.

Multiple organ failure is the most common cause of death in critically ill patients in the United States. Acute respiratory failure is the most important single component of this clinical scenario, with a mortality risk > 50%. Key pathophysiologic events occur in the pulmonary microvasculature at the interface between circulating elements and the external environment. In particular, the response of the alveolar capillary endothelial cell is of fundamental importance in this injury process. A variety of clinical stimuli initiate a systemic inflammatory response that contributes to acute microvascular lung injury. Sepsis, trauma, thermal injury, acute pancreatitis, and ischemia-reperfusion injury are among these stimuli. The particular emphasis of this review is on events associated with intestinal ischemia-reperfusion, a common and important clinical event. The pathogenic mechanisms that lead to acute lung injury in this setting are not completely understood, although it is clear that neutrophil-endothelial interactions regulated by both humoral and local mediators are crucial. Oxygen-derived free radicals, proteases, cytokines, eicosanoids, endotoxin, complement activation products, and probably platelet activating factor and nitric oxide are involved as either signalling or effector molecules. The key cellular participants during the acute phase of injury are the polymorphonuclear neutrophil (PMN) and the microvascular endothelial cell. Each of these participants is considered with regard to phlogistic behavior and the potential for therapeutic intervention. Adherence of the neutrophil to the endothelium creates a microenvironment in which PMN-derived oxidants, proteases, and cationic proteins are discharged under conditions that lead to cellular injury. Loss of microvascular integrity results and pulmonary dysfunction follows. At present, we offer only nonspecific supportive care for patients with this problem. However, investigations into relevant molecular and cellular regulatory events offer important opportunities for directed therapy. We are now approaching the threshold for utilization of several new and specific approaches. While no single pharmacologic therapy is likely to be curative for this complex problem, it is probable that certain approaches will be of clinical benefit in the near future. This review is designed to provide a basis for understanding this evolution.

Animals↗

PubMed1992

Pulmonary endothelial cell ATP depletion following intestinal ischemia.

Multiple organ failure (MOF) is known to follow systemic inflammatory mediator activation associated with intestinal ischemia-reperfusion injury. In particular, the pulmonary microvasculature appears to be susceptible to MOF-related injury. This study was designed to evaluate the hypothesis that non-cellular plasma factors associated with intestinal ischemia without reperfusion also mediate pulmonary endothelial cell injury. Male Sprague-Dawley rats had intestinal ischemia induced by microvascular clip occlusion of the superior mesenteric artery for 30, 60, 90, or 120 min. Following each period of ischemia, plasma samples were obtained from the protal vein. Time-matched sham-operated animals served as controls. Monolayers of cultured rat pulmonary artery endothelial cells were then incubated with the plasma samples and ATP levels determined using a luciferin-luciferase assay. A 51Cr-release assay using labeled endothelial cells was performed under identical conditions to assess cytotoxicity. Endothelial cell ATP levels were 1.99 +/- 0.23 x 10(-11) mole/micrograms DNA in sham preparations. After a 4-hr incubation in plasma from the 90 and 120 min ischemia groups, cellular ATP levels fell significantly to 1.07 +/- 0.23 x 10(-11) mole/micrograms DNA, respectively (P less than 0.005). No significant cytotoxic injury resulted from incubation with plasma from the 120 min group (1.0 +/- 0.4% versus 0.8 +/- 0.4% in sham group, P = NS). All animals survived 24 hr in the sham, 30, and 60 min groups. However, survival was 40 and 0% in the 90 and 120 min groups, respectively (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1991

Redo fundoplication in infants and children with recurrent gastroesophageal reflux.

The Nissen fundoplication is well established as the surgical treatment for medically refractory gastroesophageal reflux (GER) in childhood. Recurrent GER following fundoplication is a challenging problem with a reported incidence ranging from 0% to 12%. From January 1974 to January 1989, 286 children have been treated for GER with Nissen fundoplication and gastrostomy tube placement at the University of Michigan C.S. Mott Children's Hospital; 242 of these children have been followed for an average of 30 months, the remaining 44 have been lost to follow-up. Twenty-nine children (12%) have developed recurrent reflux following fundoplication. Medical management with thickened upright feelings, gastrostomy feedings, or gastrojejunostomy tube feedings has been successful for 11 children with control of reflux symptoms. Five additional children who were treated nonoperatively died of coexistant medical problems within 2 months following documentation or recurrent reflux. The remaining 13 children have required redo fundoplication for wrap disruption or herniation, and an additional six children, initially treated at other institutions, have also undergone redo fundoplications. One other child treated at this hospital required redo fundoplication for a postoperative partial gastric volvulus causing gastric outlet obstruction. Of the 20 children who have undergone a second Nissen fundoplication, 16 (80%) are doing well without recurrent GER. Four children have developed recurrent GER with wrap disruption; 1 is doing well following a third fundoplication, 2 have been managed successfully with continuous feedings via gastrojejunostomy feeding tubes, and a fourth child died of complications related to a recurrent tracheoesophageal fistula. Conservative management with gastrojejunal tube feedings should be considered in the initial management of children with recurrent GER following fundoplication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Hepatocellular oxidant stress following intestinal ischemia-reperfusion injury.

Reperfusion of ischemic intestine results in acute liver dysfunction characterized by hepatocellular enzyme release into plasma, reduction in bile flow rate, and neutrophil sequestration within the liver. The pathophysiology underlying this acute hepatic injury is unknown. This study was undertaken to determine whether oxidants are associated with the hepatic injury and to determine the relative value of several indirect methods of assessing oxidant exposure in vivo. Rats were subjected to a standardized intestinal ischemia-reperfusion injury. Hepatic tissue was assayed for lipid peroxidation products and oxidized and reduced glutathione. There was no change in hepatic tissue total glutathione following intestinal ischemia-reperfusion injury. Oxidized glutathione (GSSG) increased significantly following 30 and 60 min of reperfusion. There was no increase in any of the products of lipid peroxidation associated with this injury. An increase in GSSG within hepatic tissue during intestinal reperfusion suggests exposure of hepatocytes to an oxidant stress. The lack of a significant increase in products of lipid peroxidation suggests that the oxidant stress is of insufficient magnitude to result in irreversible injury to hepatocyte cell membranes. These data also suggest that the measurement of tissue GSSG may be a more sensitive indicator of oxidant stress than measurement of products of lipid peroxidation.

Animals↗

PubMed1990

The value of intestinal myotomy and myectomy in improving the reservoir capacity of the endorectal pull-through.

In laboratory models of massive small bowel resection and colectomy, intestinal myotomy has been shown to decrease stool frequency and malabsorption. Using physiologic and anatomic parameters of gastrointestinal function, we assessed the ability of three types of ileal myotomies to improve outcome after total abdominal colectomy, mucosal proctectomy, and endorectal pull-through (ERPT) without an enteric reservoir. Twenty puppies underwent ERPT. These dogs were randomly assigned to three experimental groups or a control group consisting of animals without a myotomy. The myotomies were performed by excising the serosa and muscularis propria of the ileal wall in three different patterns. There was no difference between any of the groups with respect to general health, postoperative weight gain, stool frequency, intestinal transit time, water absorption, electrolyte absorption, barium enemas, neorectal capacity and dimensions, and histology.

Adenomatous Polyposis Coli↗

PubMed1989

Long-term radiographic follow-up of the Nissen fundoplication in children.

This study examined 46 children 5-9 years (mean 6.7) after Nissen fundoplication surgery for gastroesophageal reflux (GER). Eleven were deceased and ten of the 35 families declined objective evaluation. The remaining 25 children (71%) had a barium swallow examination. In 16 of the 25 patients the fundoplication was intact. In 2 patients a small portion of the fundoplication was displaced above the diaphragm. In 5 patients there was residual esophageal disease. In 3 patients (one with esophageal disease), with a hiatus hernia prior to surgery, despite immediate postoperative reduction, the barium swallow examination done for this study revealed recurrent hiatus hernia but no GER. Long-term results of the Nissen fundoplication reveal success in eliminating clinically significant gastroesophageal reflux. Those patients with esophageal disease prior to the surgery need close interval follow-up to monitor continuing problems.

Child↗

PubMed1989

Late results of fundoplication for gastroesophageal reflux in infants and children.

The Nissen fundoplication (NFP) for the management of severe gastroesophageal reflux (GER) in infants and children has become one of the most frequently performed operations in pediatric surgical centers in the United States. Short-term outcome, morbidity, and mortality are consistently favorable in several large series. The long-term success of this procedure is presumed but has not been established objectively. To examine the late results of this operation, 46 infants and children were carefully evaluated more than 5 years after NFP (mean, 6.7 years). Evaluation included parental interview, physical examination, upper gastrointestinal series, and esophageal pH monitoring. The mean age at the time of operation was 4.13 years. Fifty-seven percent of the patients had significant neurologic impairment, and 80% had at least one serious additional medical problem. Twenty-four percent of the children died during the period of follow-up--all but one death related to serious underlying medical problems. Of the 35 survivors, 26 (74.3%) have no symptoms; five (14.3%) have mild symptoms potentially referable to GER that necessitate little if any treatment; four (11.5%) have had symptomatic recurrence of GER necessitating repeat fundoplication. Three of these patients now have no symptoms. Forty-five percent of the patients had at least one postoperative complication. NFP provides efficacious, long-term treatment of GER in infants and children, with acceptable morbidity. Mortality in this group of children is related primarily to associated diseases rather than to GER.

Adolescent↗

PubMed1988

Diagnostic dilemmas in patients with cystic neoplasms of the pancreas.

Cystic neoplasms of the pancreas (CNP) are rare lesions that can be difficult to diagnose preoperatively. Twenty patients with cystic neoplasms of the pancreas including five microcystic adenomas, six benign mucinous cystic neoplasms, three malignant mucinous cystic neoplasms, two solid and papillary epithelial neoplasms, and four cystic neuroendocrine tumors were treated at a single institution between 1962 and 1987. The average duration of symptoms prior to diagnosis was 10 months. Five patients were asymptomatic. Forty percent of patients presented with an abdominal mass. Plain abdominal x-rays and UGI barium contrast studies were never diagnostic. Ultrasonography, computerized tomography (CT) and visceral angiography aided in the correct diagnosis in 28%, 36%, and 75% of patients studied, respectively. Overall a correct diagnosis was made preoperatively in only 35% of patients. Twelve of 13 patients were correctly diagnosed at laparotomy with intraoperative biopsy. Without biopsy the mass was misdiagnosed at laparotomy in five of six cases. CNP must be suspected in any patients who present with an upper abdominal mass with or without abdominal pain and no history of pancreatitis. CT may be diagnostic in up to one third of cases and should be obtained routinely to demonstrate the proximity of the lesion to other structures. Visceral angiography should also be obtained prior to operation. A generous incisional biopsy should be obtained of all pancreatic cysts that are not to be resected.

Adult↗

PubMed1988

Therapeutic dilemmas in patients with symptomatic polycystic liver disease.

Most reports of the operative treatment of symptomatic polycystic liver disease (PCLD) are anecdotal or consist of only a small subset of patients in an institution's overall experience treating hepatic cysts. We have reviewed our experience with nine consecutive patients with symptomatic PCLD undergoing operative treatment from 1981 to 1987. Indications for operation include chronic abdominal pain (4 patients), cyst infection (2 patients), biliary obstruction (2 patients), inferior vena cava obstruction (2 patients), and symptomatic abdominal distention (2 patients). The average duration of symptoms leading to operation was 7.8 months. Three types of cystic disease were identified based on gross morphology: dominant cystic disease (3 patients), diffuse cystic disease (4 patients), and mixed cystic disease (2 patients). Operations to treat symptomatic PCLD included unroofing and external drainage of infected cysts (2 operations), simple unroofing (1 operation), cyst fenestration alone (4 operations) and fenestration combined with resection (3 operations). Treatment directed at principally dominant cysts (five patients) was associated with resolution of symptoms and low morbidity and mortality. Treatment directed at diffusely cystic disease (four patients) resulted in significant morbidity and mortality including three deaths. Successful surgical treatment of symptomatic patients with PCLD depends on accurate preoperative identification of patients with symptoms related to one or more dominant cysts. In this setting fenestration or simple unroofing of the dominant cyst is safe and effective treatment. By comparison, extensive fenestration with or without hepatic resection in patients with symptoms attributed to a diffusely cystic liver may be associated with unacceptable morbidity and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗