Relative contributions of afferent vagal fibers to resistance to diet-induced obesity.

BACKGROUND: We previously demonstrated vagal neural pathways, specifically subdiaphragmatic afferent fibers, regulate expression of the intestinal sodium-glucose cotransporter SGLT1, the intestinal transporter responsible for absorption of dietary glucose. We hypothesized targeting this pathway could be a novel therapy for obesity. We therefore tested the impact of disrupting vagal signaling by total vagotomy or selective vagal de-afferentation on weight gain and fat content in diet-induced obese rats. METHODS: Male Sprague-Dawley rats (n = 5-8) underwent truncal vagotomy, selective vagal de-afferentation with capsaicin, or sham procedure. Animals were maintained for 11 months on a high-caloric Western diet. Abdominal visceral fat content was assessed by magnetic resonance imaging together with weight of fat pads at harvest. Glucose homeostasis was assessed by fasting blood glucose and HbA1C. Jejunal SGLT1 gene expression was assessed by qPCR and immunoblotting and function by glucose uptake in everted jejunal sleeves. RESULTS: At 11-months, vagotomized rats weighed 19% less (P = 0.003) and de-afferented rats 7% less (P = 0.19) than shams. Vagotomized and de-afferented animals had 52% (P < 0.0001) and 18% reduction (P = 0.039) in visceral abdominal fat, respectively. There were no changes in blood glucose or glycemic indexes. SGLT1 mRNA, protein and function were unchanged across all cohorts at 11-months postoperatively. CONCLUSIONS: Truncal vagotomy led to significant reductions in both diet-induced weight gain and visceral abdominal fat deposition. Vagal de-afferentation led to a more modest, but clinically and statistically significant, reduction in visceral abdominal fat. As increased visceral abdominal fat is associated with excess morbidity and mortality, vagal de-afferentation may be a useful adjunct in bariatric surgery.

The effect of different sealer removal protocols on the bond strength of AH plus-contaminated dentine to a bulk-fill composite.

The integrity of composite bonding for post-endodontic restorations may be compromised by sealer contamination. This study assessed the effect of different sealer removal regimes on the bond strength of dentine to composite resin. Dentine surfaces were contaminated with AH Plus sealer (Dentsply DeTrey, Konstanz, Germany), followed by removal with either dry cotton pellets, cotton pellets saturated with 95% ethanol, AH Plus cleaner or external surface preparation. Dentine surfaces were not contaminated in a positive control group. A bulk-fill composite (SDR; Dentsply) was bonded with Prime&Bond active universal adhesive (Dentsply) onto the prepared surface. Composite resin-dentine beams were produced, and tensile bond strength was determined using a universal testing machine. Using an etch-and-rinse adhesive, bond strengths varied from 21.34 to 29.11 MPa with no statistical differences among removal protocols. In conclusion, contamination by AH Plus sealer does not appear to substantially interfere with bond strength between dentine and a bulk-fill composite/etch-and-rinse system.

Loss of heterozygosity of markers on chromosome 11 in tumors from patients with multiple endocrine neoplasia syndrome type 1.

Multiple endocrine neoplasia type 1 is an autosomal dominant condition characterized by the development of parathyroid hyperplasia, pituitary adenomas, and pancreatic islet cell tumors. Recently the gene for multiple endocrine neoplasia type 1 was mapped to the long arm of chromosome 11 between the loci PGA and INT2. We tested the hypothesis that tumor development is the result of a somatic deletion that unmasks a constitutional mutation. By investigating DNA isolated from tumors and somatic tissues in 12 patients from 4 different families with multiple endocrine neoplasia type 1, we found loss of heterozygous markers mapped to 11q13 in 9 (82%) of 11 informative tumors. In contrast, we were unable to identify allelic loss from other chromosomes using a variety of informative probes. This high incidence of chromosomal deletion of 11q13 suggests that this region is important in the oncogenesis of this disorder.

Tumors of the small intestine.

Tumors of the small intestine offer a unique challenge. As a result of their infrequent occurrence, they invariably present difficult problems in diagnosis and management. Although the prognosis for benign lesions is excellent, malignant small bowel tumors are perhaps the most devastating GI malignancies; at the time of diagnosis, only approximately 50% of these lesions are completely resectable for cure. Symptoms are often absent until the tumor has progressed to produce a complication. Even then, the presentation is often vague and nonspecific, intermittent pain, obstruction, and chronic anemia. The cornerstone of diagnosis is the contrast radiograph. However, in practice only about 50% of these lesions are diagnosed radiographically before surgery. This situation is further complicated by the variety of small bowel tumors, each with different symptoms and manifestations. Surgical excision is the treatment of choice for almost every small intestinal neoplasm. For most benign lesions simple excision is adequate. In contrast, for malignancies, segmental resection including as much adjacent mesentery as is reasonable, is required. In the duodenum, these tumors may necessitate pancreaticoduodenectomy; in the ileum, right colectomy may be required. In the case of advanced disease, palliative resection to relieve bleeding or obstruction may be indicated. The challenge of the future will be to reduce the morbidity and mortality of small bowel neoplasms not only by earlier recognition, diagnosis, and therapy but also through the development of alternative or adjunctive therapy for patients in whom surgical cure is not possible. This will require not only a high index of suspicion when confronted with patients with vague abdominal complaints but also an aggressive approach to diagnosis in the face of normal initial studies. In addition, multi-institutional trails of chemotherapy and radiation therapy of these tumors are needed.

Effect of aspirin on epithelial cell membrane potentials of gastric fundic mucosa.

The effects of aspirin on epithelial cell membrane potentials of Necturus fundic mucosa were examined by in vitro experiments according to intracellular microelectrode techniques. Stable intracellular impalements were obtained with 15 to 50 M-ohm microelectrodes filled with 3M KCl. In neutral mucosal solutions (pH 7.0) aspirin (5.0 mM) resulted in a significant increase in apical cell membrane potential (Vmc) from -36.7 +/- 1.5 mV to -43.3 +/- 2.3 mV (p less than 0.001) and basolateral cell membrane potential (Vcs) from -42.7 +/- 1.8 mV to -50.6 +/- 2.4 (p less than 0.001). This hyperpolarization of the cell was associated with an increase in transmucosal potential from -5.8 +/- 0.7 to -7.4 +/- 0.9 (p less than 0.05) and an increase in the ratio of apical to basolateral membrane resistances from 5.1 +/- 1.2 to 8.8 +/- 1.9 (p less than 0.05). These changes were consistent with an increase in potassium conductance induced by the salicylate anion. In acidic mucosal solutions (pH 4.5) aspirin caused a reduction in Vmc and Vcs. This hypopolarization of the cell membrane is consistent with acidification of the epithelial cells. These observations support the proposed mechanisms of aspirin injury: (1) back diffusion of H+ into the cells and (2) influx of the salicylate anions into the cells, which may interfere with intracellular metabolism.

Effect of 16,16-dimethyl prostaglandin E2 on gastric epithelial cell membrane potentials and resistances.

Intracellular microelectrode techniques were employed to examine the effects of 16,16-dimethyl prostaglandin E2 (dmPGE2) on Necturus antral mucosa epithelial cell membrane potentials and resistances. Necturus antral mucosa was mounted in a modified Ussing chamber and stable intracellular impalements were obtained. Addition of 0.01 microgram/ml dmPGE2 to the mucosal solution produced an increase of the apical cell membrane potential (Vmc) from -44.3 +/- 3.1 to -53.5 +/- 3.8 mV (p less than 0.001) and of the basolateral cell membrane potential (Vcs) from -48.8 +/- 2.8 to -57.7 +/- 3.2 mV (p less than 0.001). This reversible, dose-dependent hyperpolarization of both cell membranes was accompanied by a decrease in the electrical resistance of the apical membranes (Ra) from 2550 +/- 250 omega/cm2 to 1870 +/- 210 omega/cm2 (p less than 0.05) and a decrease in the resistance of the basolateral membrane (Rb) from 1020 +/- 250 omega/cm2 to 630 +/- 80 omega/cm2 (p less than 0.05). In addition, there was an increase in the resistance of the shunt (intercellular junction, Rs), the major route of transepithelial ion flow, from 710 +/- 60 omega/cm2 to 750 +/- 80 omega/cm2 (p less than 0.05). Thus dmPGE2 increased the cell membrane potentials and reduced the ionic permeability of the intercellular junction.

Comparison of gastric mucosal blood flow as measured by H2 gas clearance and microspheres during secretory stimulation and inhibition.

H2 clearance is a recently described method of measuring gastric mucosal blood flow that has great potential for clinical use. However, the effects of luminal pH and of secretory activity of the gastric mucosa on the accuracy of H2 clearance measurements have not been systematically examined. We therefore tested the validity of H2 clearance measurements at different pHs in both in vitro and in vivo systems. In addition, we compared measurements by H2 clearance and radioactive microspheres during stimulation and suppression of acid secretion. In vitro, H2 washout was relatively constant over a range of pHs from 2.0 to 8.0. In chambered segments of canine fundus in vivo, H2 clearance was not significantly affected by pH of the luminal solutions either in the resting state or at lower blood flows induced during infusion of vasopressin. Finally, there was a close correlation (r = 0.85; p less than 0.001) between H2 clearance and microsphere measurements under resting conditions, during intravenous histamine stimulation, and after infusion of cimetidine to suppress acid secretion. In summary, H2 clearance reliably and accurately measures gastric mucosal blood flow at different luminal pHs and under conditions that stimulate or suppress acid secretion.

Intracellular pH (pHi) in gastric surface epithelium is more susceptible to serosal than mucosal acidification.

Intracellular microelectrode techniques were used to examine the effects of mucosal or serosal acidification on intracellular pH (pHi) in gastric surface epithelial cells. Necturus antrum was mounted in a modified Ussing chamber, and pHi was determined from the difference between the potentials recorded by intracellular conventional and pH-sensitive microelectrodes. In tissues bathed with bicarbonate-buffered Ringer's solution (pH 7), acidification of the mucosal solution to pH 4.5 by isotonic replacement of the NaHCO3 with NaCl had no significant effects on pHi. In contrast, acidification of the serosal solution to pH 4.5 by replacing the bicarbonate reduced pHi from 7.32 +/- 0.04 to 6.95 +/- 0.06 (p less than 0.001, n = 8). Similarly, in tissues bathed with HEPES-buffered Ringer's solution (pH 7.0), pHi was unaffected by reducing the mucosal solution pH to 4.5 with HCl but fell 0.21 +/- 0.05 pH units (p less than 0.01, n = 7) during acidification of the serosal solution to pH 6. These results suggest that gastric epithelium is more sensitive to acidification from the serosal than the mucosal side. Such a finding is consistent with the concept of a gastric mucosal barrier to luminal acid. It may also explain the gastric epithelium's greater sensitivity to acute ulceration during systemic acidosis.

Regional gastric mucosal blood flow after parietal cell vagotomy in dogs.

In this study we used the recently validated H2 clearance method to perform endoscopic measurements of gastric mucosal blood flow (MBF) in anesthetized dogs before and after parietal cell vagotomy (PCV). Under resting conditions, MBF in the gastric corpus before PCV was 72 +/- 5 ml/min/100 gm. This was not altered significantly at 4, 8, or 16 weeks after PCV, and there were not significant long-term changes in MBF on the greater or lesser curvatures of the corpus individually. Before PCV infusion of pentagastrin (8 micrograms/kg/hr) elicited increases in corpus MBF to 104 +/- 4 ml/min/100 gm, accompanied by increases in gastric acid output from resting levels of 2.1 +/- 0.9 to 38.6 +/- 2.4 mEq/hr (p less than 0.001). PCV significantly reduced pentagastrin-stimulated acid secretion by 50%, and secretory inhibition was accompanied by significant reductions in pentagastrin-stimulated MBF in the corpus. Pentagastrin did not alter antral MBFs before or after PCV. In summary PCV does not elicit significant long-term changes in resting MBF in different regions of the gastric corpus, and PCV significantly diminishes increases in acid output and corpus MBF that are normally stimulated by pentagastrin. These observations suggest that alterations in gastric MBF after PCV may be attributable to alterations in acid secretion.

Focal adhesion kinase gene silencing promotes anoikis and suppresses metastasis of human pancreatic adenocarcinoma cells.

BACKGROUND: Inadequate or inappropriate cell-substrate contact triggers a subset of apoptotic cell death, termed anoikis. Resistance to anoikis is a characteristic of malignant cells that is associated with increased tumorigenesis and metastasis. Focal adhesion kinase (FAK) is an important regulator of cell survival and migration and cell cycle progression. We tested the hypothesis that FAK gene silencing would promote anoikis and reverse acquired anoikis resistance in human pancreatic adenocarcinoma cells. METHODS: FAK expression was assessed by Northern and Western blot analysis. Anoikis was induced in PANC1, BxPC3, MiaPaCa2, and Mia(AR) (an anoikis-resistant derivative of MiaPaCa2) with the use of polyHEMA culture. FAK expression was suppressed by RNA interference. Anoikis was detected by YO-PRO-1/propidium iodide staining and flow cytometry. Fluorometric caspase profiling was performed. Metastasis was assayed in a nude mouse orthotopic xenograft model. RESULTS: The cell lines that were tested showed marked variation in their anoikis resistance, greater resistance being associated with higher levels of FAK expression. FAK gene silencing promoted anoikis in all cell lines and reversed acquired anoikis resistance in Mia(AR), which was associated with increased caspase activation. Suppression of FAK expression also inhibited metastasis in the nude mouse model. CONCLUSION: FAK gene silencing suppresses anoikis resistance in pancreatic adenocarcinoma cells. FAK represents a potential target for novel antimetastatic therapies.

Pancreatic interstitial pH regulation: effects of secretory stimulation.

BACKGROUND: Bicarbonate secretion by pancreatic ducts presumably releases an equivalent amount of acid into the parenchyma. The purpose of this study was to determine the effects of this acid load on pancreatic interstitial pH (pHI). In addition, we examined the relationship of pHI to changes in pancreatic blood flow (PBF), which may be important in acid disposal. METHODS: After validation of a microelectrode method for measurement of pHI in anesthetized cats, the effects of secretin (2 IU/kg intravenously) and cholecystokinin (0.08 microgram/kg intravenously) were examined. PBF was measured simultaneously by the H2 gas clearance technique. RESULTS: Secretory stimulation with secretin produced an increase in pancreatic bicarbonate secretion (146 +/- 23 microEq/15 minutes, p < 0.01). This secretion was associated with a fall in pHI from 7.36 +/- 0.02 to 7.31 +/- 0.02 (p < 0.001), which returned to baseline after 25 minutes. There was an accompanying increase in PBF from 118 +/- 32 to 148 +/- 35 ml/min/100 gm (p < 0.01). In contrast, stimulation with cholecystokinin only slightly increased pancreatic secretion (49 +/- 19 microliters/15 minutes) and had no significant effects on pH or blood flow. CONCLUSIONS: These results suggest that pancreatic secretion of bicarbonate, but not protein, releases H+ into the interstitium, an acid tide comparable to the alkaline tide during acid secretion by the stomach. This interstitial acidosis was accompanied by an increase in PBF. The increase in blood flow may be important in pH homeostasis, contributing to the disposal of this acid.

Interleukin-10 prevents death in lethal necrotizing pancreatitis in mice.

BACKGROUND: Cytokines derived from macrophages may play an integral role in the evolution of acute pancreatitis. Interleukin-10 (IL-10), a potent antiinflammatory cytokine, prevents the activation of macrophages and their release of inflammatory cytokines. The aim of this study was to determine whether treatment with IL-10 decreased the severity of experimental acute pancreatitis. METHODS: Thirty female Swiss Webster mice were divided into three groups. Acute pancreatitis was induced by using a choline-deficient, 0.5% ethionine supplemented (CDE) diet. Group A (controls) received CDE diet alone. Group B was pretreated with 10,000 units of intraperitoneal IL-10 at the onset of feeding and every 8 hours thereafter. Group C received IL-10 33 hours after beginning the CDE diet and every 8 hours thereafter. One half of the animals in each group was killed at 54 hours; the remaining living animals were killed at 80 hours. Serum amylase levels (units per liter) were determined at 54 and 80 hours. Pancreata were harvested and fixed in formalin. Histologic characteristics were graded on a scale from 0 to 4 (normal to most abnormal) in a blinded fashion by two investigators. RESULTS: Serum amylase level and histologic score (edema, inflammation, hemorrhage, and necrosis) were significantly reduced when IL-10 was administered either prophylactically or therapeutically (p < 0.01). At 54 hours all animals were alive. Mortality was reduced at 80 hours in both groups treated with IL-10 compared with those fed the CDE diet alone (p < 0.001). CONCLUSIONS: These results suggested that macrophages play an integral role in determining the severity of acute pancreatitis in this animal model. The finding that IL-10 decreased inflammation and prevented death, even when given after acute pancreatitis was established, suggests that it may have potential for clinical use.

Stenting does not decompress the pancreatic duct as effectively as surgery in experimental chronic pancreatitis.

BACKGROUND: In humans with chronic pancreatitis (CP), pancreatic interstitial pressure (IP) is elevated and pancreatic blood flow (PBF) is reduced. The efficacy of surgical decompression (SD) of the pancreatic duct (ie, pancreaticojejunostomy) is believed to be due to its ability to decrease IP and pancreatic vascular resistance (Rp), which increases PBF. Pancreatic duct stenting (STE) also probably reduces IP and Rp, which may explain its efficacy. The purpose of this study was to compare the efficacy of SD with STE. METHODS: CP in cats was created by narrowing the main pancreatic duct. Six weeks later, CP and normal pancreata were isolated and perfused ex vivo under basal conditions and after secretin stimulation. In normal and CP glands, IP and perfusion pressure were measured and Rp (U) was calculated. In two additional groups, the pancreatic duct was decompressed, either by stenting or by complete transection of the duct with a longitudinal capsulotomy. RESULTS: In CP glands, IP and Rp were increased and secretory output was markedly reduced compared with the normal (0.65 +/- 0.30 mm Hg and 0.46 +/- 0.04 U vs 3.90 +/- 0.80 mm Hg and 1.68 +/- 0.05 U; P < .05). Secretin administration (2 units) increased IP and Rp in CP glands (6.60 +/- 1.10 mm Hg and 2.87 +/- 0.07 U; P < .05), but these values did not chang in normal glands (0.81 +/- 0.20 and 0.53 +/- 0.03 U; NS). STE and SD decreased IP and Rp in CP glands (2.20 +/- 0.20 to 1.0 +/- 0.40 mm Hg and 1.20 +/- 0.015 to 0.90 +/- 0.01 U, respectively; P < .05). Both methods prevented an increase of IP and Rp after secretin administration. IP and Rp decreased to a greater degree following SD, compared with STE (P < .05). CONCLUSIONS: Both STE and SD decreased IP and Rp in this experimental model of CP. However, SD was significantly more effective than STE.

Up-regulation of Na+,K+ adenosine triphosphatase after massive intestinal resection.

BACKGROUND: The mechanisms of intestinal adaptation after resection are not completely defined. The purpose of this study was to examine the changes after resection in the enterocyte basolateral Na+,K+ adenosine triphosphatase (ATPase) known to play a critical role in epithelial transport and homeostasis. METHODS: Lewis rats underwent 70% small bowel resection or transection. At 6 hours, 24 hours, 1 week, and 2 weeks, jejunum and ileum were harvested for analysis of Na+,K+ ATPase activity, kinetic analysis, and alpha 1-ATPase messenger RNA and protein levels. RESULTS: Na+,K+ ATPase activity increased (p < 0.05) in both the jejunum and ileum by 2 weeks after resection. This rise in activity correlated with an increase in the maximal activity of ATPase, from 20.8 to 101.01 mumol inorganic phosphate.mg-1.hr-1. ATPase messenger RNA levels increased sixfold in the jejunum and tenfold in the ileum by 2 weeks after resection (p < 0.05). Protein levels rose at 6 hours and remained elevated in both tissues. CONCLUSIONS: After intestinal resection, enterocyte Na+,K+ ATPase activity rises as a result of an increase in the number of transporters per cell. This occurs through both transcriptional and translational mechanisms. It appears that intestinal adaptation after resection involves not only an increase in absorptive surface area but also functional adaptation by the individual enterocyte.

Peptide YY immunoneutralization inhibits meal-induced absorption in vivo.

BACKGROUND: Plasma peptide YY (PYY) levels rise after a meal and have recently been shown to increase small bowel-absorption. The purpose of this study was to determine whether immunoneutralization of PYY would block postprandial absorption in vivo. METHODS: Exteriorized, neurovascularly intact jejunal and ileal segments (25 cm) were created in six mongrel dogs. After a 2-week recovery luminal perfusion with an isotonic buffer, containing [14C]-polyethylene glycol as a volume marker, was used to analyze water and sodium flux after an oral meal. Each meal was accompanied by either intravenous anti-PYY (0.5 mg.kg-1.h-1) or nonspecific immunoglobulin IG (control). PYY antibody binding was determined by radioimmunoassay. RESULTS: Displacement studies showed complete PYY neutralization. In control experiments feeding increased absorption of sodium and water in both segments. PYY immunoneutralization had no effect on jejunal absorption but significantly diminished ileal absorption (p < 0.05). CONCLUSIONS: These results suggest that PYY acts selectively in the ileum to increase postprandial fluid and electrolyte absorption after a meal. Agents directed at PYY-stimulated absorption may prove to be of therapeutic benefit in patients with malabsorptive conditions.

Interleukin-10 reduces the systemic inflammatory response in a murine model of intestinal ischemia/reperfusion.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) is known to increase systemic cytokine levels, as well as to activate neutrophils in distant organs. This study was designed to investigate the effect of interleukin-10 (IL-10) on cytokine release, pulmonary neutrophil accumulation, and histologic changes in a murine model of I/R. METHODS: Forty female Swiss-Webster mice were divided into four groups. Group 1 underwent 45 minutes of superior mesenteric artery occlusion followed by 3-hour reperfusion (I/R). Group 2 underwent laparotomy alone (Sham). Group 3 underwent I/R, but was treated with IL-10, 10,000 units IP every 2 hours, starting 1 hour before reperfusion (Pretreatment). Group 4 was treated with an equal dose of IL-10, starting 1 hour after reperfusion (Posttreatment). All animals were killed at 3 hours, standard assays were performed for serum cytokine levels, and lung myeloperoxidase activity and intestinal histology were scored. RESULTS: Serum cytokines (TNF-alpha and IL-6), lung myeloperoxidase levels, and histologic score were significantly reduced when IL-10 was administered either before or after reperfusion. CONCLUSIONS: IL-10 reduced the severity of local and systemic inflammation in a murine model of intestinal I/R when given before or after reperfusion injury. These observations suggest that IL-10 may exert its effect by blocking cytokine production and distant organ neutrophil accumulation.

An ETa/ETb endothelin antagonist ameliorates systemic inflammation in a murine model of acute hemorrhagic pancreatitis.

BACKGROUND: Endothelin peptides are polykines with strong vasoconstrictor properties. We have previously shown that endothelin antagonism (PD145065) reduces the local severity of acute pancreatitis. We now investigated the effect of endothelin antagonism on systemic inflammation in a model of acute hemorrhagic pancreatitis. METHODS: Forty-two mice were divided into four groups. Group 1 was fed standard food plus PD145065 every 8 hours. Group 2 was fed a choline-deficient ethionine (CDE) supplemented diet and given saline every 8 hours. Group 3 was fed a CDE diet and treated with PD145065 every 8 hours from initiation of diet. Group 4 was fed a CDE diet and given PD145065 from 48 hours after initiation of diet. Animals were killed at 70 hours. Serum was collected. Pancreata and lung tissue were harvested. RESULTS: Histology score, serum amylase level, lung myeloperoxidase, and interleukin (IL)-10 were all significantly reduced in both treatment groups (groups 3 and 4) (p < 0.05). IL-6 levels were reduced in group 3 only (p < 0.05). The mortality rate did not differ among any of the groups. CONCLUSIONS: Endothelin antagonism decreased the severity of acute pancreatitis and reduced markers of systemic inflammation. Late treatment at 48 hours failed to prevent the rise in IL-6. Mortality rates were unaffected by treatment.

Sepsis increases the plasma membrane content of alpha1 and alpha2 isoforms of Na+-K+ adenosine triphosphatase in rat skeletal muscle.

HYPOTHESIS: Increased Na(+)-K(+) adenosine triphosphatase (ATPase) activity in skeletal muscle during sepsis is caused by transient increases in enzyme content within the plasma membrane. DESIGN: Randomized controlled study. SETTING: University laboratory. INTERVENTION: Eighty-eight adult male Wistar rats were randomly assigned to undergo cecal ligation and puncture (CLP) or sham operation. MAIN OUTCOME MEASURES: Gastrocnemius muscles were harvested 6, 12, 24, and 48 hours after operation and Na(+)-K(+) ATPase activities were measured spectrofluorimetrically. Messenger RNA (mRNA) levels for the alpha1 and alpha2 isoforms of Na(+)-K(+) ATPase were determined by Northern blot analysis. Crude membranes, internal membranes, and purified plasma membranes were isolated from gastrocnemius muscles and protein levels of alpha1 and alpha2 isoforms were determined by Western blot analysis. RESULTS: Na(+)-K(+) ATPase activity in the CLP group was significantly higher compared with the sham group 24 hours after operation (P<.05). However, there were no differences between the sham and CLP groups 6, 12, or 48 hours after operation. No significant differences between the CLP and sham groups were noted in mRNA levels for Na(+)-K(+) ATPase alpha1 and alpha2 isoforms. Western blot analysis revealed that the plasma membrane (but not internal membrane or crude membrane) content of alpha2 and alpha1 isoforms from the CLP group was significantly increased compared with the sham group 24 hours after operation (P<.05). CONCLUSIONS: Na(+)-K(+) ATPase activity increases 24 hours after CLP in gastrocnemius muscle and then declines. This increase is caused by increased Na(+)-K(+) ATPase protein levels in the plasma membrane.

Laparoscopic cholecystectomy. The new 'gold standard'?

Laparoscopic cholecystectomy has rapidly been adopted by surgeons, but concerns remain about its safety, the management of common bile duct stones, and the means of appropriate training. Of 647 patients referred for cholecystectomy, preoperative endoscopic retrograde cholangiography was performed in 49 (7.6%), with 27 patients (4%) undergoing sphincterotomy and stone extraction. Traditional cholecystectomy was performed in 29 patients (4.5%). Laparoscopic cholecystectomy was attempted in 618 patients and completed successfully in 600 (97.1%). Surgical trainees functioned as the primary surgeon in 70% of cases. Technical complications occurred in three patients (0.5%), including one patient with a common bile duct laceration (0.2%). Major complications occurred in 10 patients (1.6%), with no perioperative mortality. Mean postoperative hospital stay was 1 day, with return to work or full activity a mean of 8 days after surgery. Two cases of retained common bile duct stones (0.3%) were identified. We now regard laparoscopic cholecystectomy as the "gold standard" therapy for management of symptomatic cholelithiasis.

Pylorus-preserving Whipple resection for pancreatic cancer. Is it any better?

OBJECTIVE: To compare the short- and long-term morbidity and mortality rates of the standard Whipple pancreatoduodenectomy (SW) and its pylorus-preserving modification (PPW) in patients with malignant periampullary disease. DESIGN: Retrospective medical record review and quality of life assessment by telephone interview. SETTING: University medical center. STUDY PARTICIPANTS: Sixty-seven patients who underwent pancreatoduodenectomy (52 SW and 15 PPW) from June 1988 to January 1994. INTERVENTION: The SW and PPW. MAIN OUTCOME MEASURES: Operative features and short- and long-term complications were analyzed with respect to the type and stage of cancer and the kind of pancreatic resection. Mean follow-up was 32 months (range, 1 to 5 years). RESULTS: The operative mortality rate for all patients who had a pancreatic resection was 1.5%. The diagnoses in the PPW vs SW groups were pancreatic cancer (four vs 27 patients), ampullary cancer (six vs seven patients), duodenal cancer (zero vs six patients), and bile duct cancer (five vs one patient). Operative mortality rates (0% vs 1.55%) and operative times (2 minutes longer for SW) were similar. Delayed gastric emptying (61% vs 41%) was more common in the PPW group, resulting in a longer hospitalization (24 vs 18 days) and a greater cost in the PPW group (P = .04). In the PPW group, a mean of five lymph nodes was removed compared with 10 in the SW group (P = .04). CONCLUSIONS: The data provided no evidence of any advantage for the PPW in patients with malignant periampullary tumors. We continue to advocate the SW for pancreatic cancer.