Structured intraoperative assessment of pancreatic gland characteristics in predicting complications after pancreaticoduodenectomy.

BACKGROUND: The morbidity rate after pancreaticoduodenectomy remains high (20-50 per cent) and postoperative pancreatic fistula (POPF) is a major underlying factor. POPF has been reported to be associated with pancreatic consistency (PC) and pancreatic duct diameter (PDD). The aim was to quantify the risk of pancreaticojejunostomy-associated morbidity (PJAM) by means of a structured intraoperative assessment of both characteristics. METHODS: This single-centre prospective observational study included pancreaticoduodenectomies performed between 2008 and 2010 with a standardized duct-to-mucosa end-to-side pancreaticojejunostomy. PC and PDD were assessed during surgery and classified into four grades each (from very hard to very soft, and from larger than 4 mm to smaller than 2 mm, respectively). PJAM was defined as POPF (grade B or C in International Study Group on Pancreatic Fistula classification) or symptomatic peripancreatic collection of either abscess or fluid. PJAM of at least Clavien grade IIIb was considered severe. RESULTS: PJAM and POPF were observed in 24 (21·8 per cent) and 17 (15·5 per cent) of 110 patients respectively. Softer PC and smaller PDD were risk factors for POPF (both P < 0·001), symptomatic peripancreatic collections (P = 0·071 and P = 0·015) and PJAM (both P < 0·001). Combining consistency and duct characteristics in a composite classification the PJAM risk was stratified as 'high' (both risk factors, PJAM incidence 51 per cent), 'intermediate' (softer PC or smaller PDD, PJAM 26 per cent) or 'low' (no risk factors, PJAM 2 per cent). Severe PJAM was observed only in patients with smaller PDD. CONCLUSION: A high-risk pancreatic gland had a 25-fold higher risk of PJAM after pancreaticoduodenectomy than a low-risk gland. This simple classification can contribute to more individualized patient management and allow stratification of study cohorts with homogeneous POPF risk.

Frameshift suppression by thyA mutants of Escherichia coli K-12.

We have extended our previous study on the suppression of frameshift mutants by Escherichia coli thyA mutants by assaying suppression of 15 rIIB frameshift mutants of bacteriophage T4 on one of our suppressing thyA mutant strains. The majority of insertion mutants were suppressible, whereas none of the deletion mutants tested was suppressible. Frameshift suppression could be inhibited by adding thymidine to the assay medium, but was not affected by the presence of a restrictive rpsL mutation in the host strain. We suggest that the frameshift suppression event occurs at a nonsense codon generated by the frameshift mutation.

Effects of raw soya diet and cholecystokinin receptor blockade on pancreatic growth and tumor initiation in the hamster.

Raw soya diet in the hamster had short-term trophic effects on the pancreas, causing significant increases in pancreatic weight, DNA, RNA, and protein. These changes appear to be mediated by cholecystokinin (CCK) because the increases were blocked by infusion of the CCKA receptor antagonist, MK329. Raw soya diet significantly increased plasma levels of CCK in both the short-term and long-term studies. However, raw soya did not potentiate pancreatic cancer in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Infusion of MK329 during the initiation period of carcinogenesis did not change tumor incidence or yield, suggesting that endogenous CCK does not influence tumor induction during the initiation period in the hamster.

Preoperative feeding does not reverse postoperative insulin resistance in skeletal muscle in the rat.

Metabolic studies on injured and postoperative patients have shown impaired glucose disposal in peripheral tissues after trauma. Using small-bowel resection as a model of surgical trauma, we investigated whether substrate availability could ameliorate the changes in muscle glucose uptake induced by trauma. We also studied the effect of preoperative feeding on postoperative insulin-stimulated insulin receptor substrate-1 (IRS-1)-associated phosphatidylinositol (PI) 3-kinase activity in both Wistar rats and genetically non-insulin-dependent diabetic Goto-Kakazaki rats (GK rats). Serum glucose, insulin, plasma epinephrine, lactate, and plasma nonesterified free fatty acids (NEFAs) were measured as indicators of the metabolic state and surgical stress. Insulin-stimulated glucose transport was significantly reduced in fed traumatized Wistar rats compared with fed nontraumatized rats (P < .05). Significant increases in in vivo insulin-stimulated IRS-1-associated PI 3-kinase activity were found in fed traumatized Wistar rats compared with fed nontraumatized Wistar rats and fasted traumatized Wistar rats, as well as fed traumatized GK rats compared with fed nontraumatized GK animals (all P < .017). Serum insulin concentrations were significantly reduced in fed traumatized Wistar and GK rats compared with the respective fed nontraumatized groups (both P < .01). Serum glucose levels were significantly elevated in fed traumatized GK rats compared with fed nontraumatized animals (P < .01). In the present study, preoperative feeding did not prevent a postoperative reduction in insulin-stimulated glucose transport in skeletal muscle. The finding that insulin-stimulated PI 3-kinase activity increased after trauma in both Wistar and GK rats indicates that postoperative insulin resistance is not caused by an impairment in the early steps of the insulin signaling pathway. The postoperative decreases in serum insulin despite high blood glucose suggest that trauma impairs the insulin response to hyperglycemia.

Radioimmunoassay of regulatory peptides in the presence of acetonitrile: marked improvement of cholecystokinin assays.

Radioimmunoassay has made it possible to measure the levels of many hormones. However, samples for some hormones, such as cholecystokinin (CCK), need to be purified by reverse phase chromatography before assay. Usually, samples are eluted from cartridges or HPLC columns in about 50% acetonitrile, dried on a vacuum centrifuge, and then reconstituted in buffer. Drying and reconstituting samples is time consuming and introduces additional sources of error and peptide loss. The present study investigated the effect of acetonitrile on radioimmunoassays for CCK to see if samples containing acetonitrile could be assayed directly. The non-specific binding of a radiolabeled peptide, the zero binding (B0), and the fall in the presence of 2.5 fmol unlabeled CCK were determined in the presence of various proportions of acetonitrile with 0.1% TFA. Additionally, standard curves were compared in the presence and absence of 200microl of 50% acetonitrile, (n = 5). For assays using two separate CCK antisera, increasing amounts of acetonitrile gave progressively higher zero binding and fall, thereby increasing sensitivity and antibody titer. The use of 200microl 50% acetonitrile, chosen to represent typical sample conditions, increased antiserum titers by three to four-fold, as well as increasing sensitivity considerably. For one antiserum (CCK2), the IC20 was 0.36+/-0.02 fmol CCK/tube in the presence of acetonitrile and 1.45+/-0.08 fmol/tube in its absence (P< 0.001). For the other antiserum (Dino 7), the IC20 was 0.40+/-0.02 fmol CCK/tube in the presence of acetonitrile and 0.63+/-0.01 fmol/tube in its absence (P<0.001). A similar increase in sensitivity was seen with a gastrin assay. However, no significant change in the gastrin antibody titer was evident. Assays for several other hormones were unaffected by 200 microl of 50% acetonitrile. At volumes encountered in samples following chromatography, acetonitrile did not adversely affect radioimmunoassays for a number of hormones, and the sensitivity and antibody titer of the CCK assays were improved. Measurement of CCK samples without drying and reconstitution increases assay efficiency and sensitivity.

Effects of long-term infusion of anorexic concentrations of islet amyloid polypeptide on neurotransmitters and neuropeptides in rat brain.

Islet amyloid polypeptide (IAPP or amylin) potently reduces food intake in rats at or near physiological concentrations. Although the mechanisms of action of IAPP are not understood, the brain is a suggested site. Changes in hypothalamic and striatal neurotransmission have been reported following acute systemic administration of a pharmacological concentration of IAPP. In the current study, we evaluated the effects of chronic administration of low doses of IAPP on satiety-related neurotransmitters and neuropeptides in the hypothalamus, hippocampus, striatum, left cortex, and right cortex of the rat. Doses of 0, 5 and 25 pmol IAPP/kg-min were administered subcutaneously for 2 or 5 days. Food intake was reduced by 27 and 44% (both P<0.001) for the 5 and 25 pmol/kg-min groups, respectively, in the 2-day experiment and was decreased by 14% (P<0.01) and 24% (P<0.001), respectively, in the 5-day experiment. Body weight was significantly decreased in a dose-dependent fashion. In the 2-day experiment, norepinephrine increased in the hypothalamus in the 5 pmol IAPP/kg-min group, and neurotensin increased in the hippocampus in the 25 pmol/kg-min rats (both P<0.05). In the 5-day, 5 pmol/kg-min rats, 5-hydroxyindoleacetic acid (5-HIAA) increased in the hypothalmus and cholecystokinin (CCK) increased in the striatum (both P<0.05). In the 5-day, 25 pmol/kg-min group, neuropeptide Y (NPY) increased in the hypothalamus (P<0.01) and CCK increased in the hypothalmus and striatum (both P<0.05). The present study confirms that IAPP is a potent anorectic peptide at low doses and suggests that IAPP not only affects classical neurotransmitters in the brain but also alters concentrations of neuropeptides known to be involved in food intake.

On the importance of cholecystokinin in neonatal pancreatic growth and secretory development in guinea pigs.

The role of cholecystokinin (CCK) in pancreatic growth and secretory development in fetal and neonatal guinea pigs was investigated by CCK receptor blockade. For the last 20 days of gestation, sows received the CCKA receptor antagonist, MK329 (25 nmol/kg/h) by continuous subcutaneous infusion. Alternatively, neonates from untreated females received an MK329 infusion for the first 4 or 15 days following birth. Pancreatic weight, DNA, RNA, protein, and amylase content per 100 g body weight and secretory responses to CCK, carbamylcholine, and phorbol ester were determined at birth and 4 days in animals receiving MK329 in utero and were measured at 4 and 15 days in neonatally infused animals. No significant changes in pancreatic growth parameters were seen in MK329-treated animals compared to controls, except for a small (14%; p < 0.02) decrease in weight after 15 days of neonatal exposure. Enhanced amylase secretion in response to CCK and carbamylcholine was seen in all groups receiving MK329 (all p values < 0.00001). Pancreatic growth and secretion were not inhibited by CCKA receptor blockade, which suggests that the effects of CCK mediated by the CCKA receptor are not essential for growth or development of the pancreatic amylase secretory response in the neonatal guinea pig.

Islet hormone secretion in pancreatic cancer patients with diabetes.

The diabetes or impaired glucose tolerance that occurs in most patients with pancreatic cancer is characterized by profound insulin resistance. Recent evidence suggests that the diabetes may result from the presence of the tumor rather than being a predisposing factor to development of the malignancy. Some islet hormones have been shown to exhibit diabetogenic effects. To investigate the potential role of these hormones in the diabetic state associated with pancreatic cancer, we measured islet hormones during fasting in pancreatic cancer patients (n = 30), patients with other malignancies (n = 43), and healthy controls (n = 25). Preoperative pancreatic cancer patients were classified as normal glucose tolerance (NGTT), impaired glucose tolerance (IGTT), non-insulin-requiring diabetes (NIRD), and insulin-requiring diabetes (IRD). Nine pancreatic cancer patients were studied after tumor removal by subtotal pancreatectomy. Some preoperative pancreatic cancer patients (n = 19), postoperative patients (n = 9), and controls (n = 8) were also studied during hyperglycemia and following glucagon injection. Fasting plasma C-peptide was elevated in NIRD pancreatic cancer patients compared to controls. Fasting levels of islet amyloid polypeptide (IAPP), glucagon, and somatostatin were elevated in NIRD and IRD patients. IAPP and glucagon, but not somatostatin, normalized following subtotal pancreatectomy. During hyperglycemia, increases in C-peptide and IAPP were seen only in controls and in NGTT and postoperative pancreatic cancer patients. After glucagon infusion, IAPP levels increased in controls and nondiabetic cancer patients; C-peptide levels increased in controls, nondiabetic patients, and NIRD. Responses of C-peptide and IAPP to glucagon normalized after pancreatectomy. During hyperglycemia, glucagon levels fell in all groups except IGTT patients and a decrease in somatostatin concentrations was seen in controls.

The path from oral nutrition to home parenteral nutrition: a qualitative interview study of the experiences of advanced cancer patients and their families.

BACKGROUND AND AIM: Little is known about the perspectives that patients with advanced cancer and their family members have concerning nutritional problems and nutritional support. The aim of this study was to investigate their experiences of the nutritional situation prior to introduction of home parenteral nutrition (HPN) in order to understand factors contributing to the decision to accept HPN. METHODS: Semi-structured interviews were conducted with 13 patients with advanced cancer who had received HPN and 11 family members. The constant comparative method was used for data analysis. RESULTS: Patients and family members described the nutritional situation prior to HPN as a source of worry and often desperation. Patients reported wanting and trying to eat, but being unable to do so. Family members experienced powerlessness and frustration, as they could not enable the patient to eat. A lack of attention to nutritional problems by the hospital staff was described. The offer of HPN came when patients and family no longer felt able to solve the nutritional problems within the family. CONCLUSION: The desperate and chaotic nutritional situation in the family led to willingness to accept HPN. Because of the severity of the problems, HPN was viewed as a positive alternative.

Abnormal plasma gut hormones in pathologic duodenogastric reflux and their response to surgery.

Fasting and postprandial plasma levels of the gut hormones gastrin, cholecystokinin (CCK), secretin, glucose-dependent insulinotropic polypeptide, motilin, neurotensin, peptide YY (PYY), enteroglucagon, glucagon, insulin, and pancreatic polypeptide were measured in 11 patients with alkaline gastritis associated with excessive duodenogastric reflux not related to previous gastric surgery (primary DGR), 12 primary DGR patients after pancreatico-biliary diversion ("duodenal switch" procedure), and in 10 age-matched healthy controls. Gastric emptying of a semisolid oatmeal was also measured in patients with primary DGR and in patients after bile diversion. Fasting plasma levels of the distal gut hormone neurotensin and the pancreatic islet hormone insulin were significantly greater in patients with primary DGR compared with controls. Neurotensin levels were normal in patients studied after bile diversion. Postprandial plasma levels, incremental integrated and total integrated responses for CCK, secretin, insulin, neurotensin, PYY, and enteroglucagon, were significantly greater in patients with primary DGR compared with controls. The majority of these responses normalized after bile diversion; however, the postprandial response for insulin and enteroglucagon remained elevated. Patients with primary DGR had a rapid early postprandial phase of gastric emptying of solids, which showed a significant correlation with plasma neurotensin levels. Bile diversion produced a significant delay in this lag-phase of gastric emptying. These abnormalities in gut regulatory hormones appear to be adaptive changes to rapid early postprandial gastric emptying, probably related to antropyloric dysmotility, which has been implicated in the pathogenesis of this condition. Measurement of these gastrointestinal hormones may become useful in the diagnosis of primary DGR.

Effect of carbohydrate feeding on insulin action in skeletal muscle after surgical trauma in the rat.

Metabolic stress after surgery is associated with peripheral insulin resistance. Recent studies have suggested that preoperative glucose can ameliorate postoperative decreases in insulin-stimulated glucose disposal. In the present experiments, we used a bowel-resection model of surgical trauma to test the hypothesis that elevations of serum insulin induced by preoperative oral glucose or ad libitum feeding affects postoperative insulin-stimulated glucose uptake in skeletal muscle. Insulin-stimulated glucose transport was measured in vitro in soleus muscles after surgical trauma in fasted rats given oral glucose or water before surgery. Insulin-stimulated glucose transport was also assessed in vitro in fasted or fed traumatized rats and non-traumatized control animals. In addition, stress hormones (glucagon, corticosterone, and adrenaline) were measured before and after surgical trauma in fasted rats and rats fed ad libitum. In vitro skeletal-muscle insulin sensitivity and responsiveness were reduced postoperatively in fasted animals that received oral glucose loads before bowel resections and in rats fed ad libitum or fasted before surgery versus non-traumatized rats (all P < 0.05). Stress-hormone concentrations after trauma did not differ between fed and fasted animals. In the current study, insulin sensitivity and responsiveness were reduced in isolated skeletal muscles after bowel resection, but neither preoperative glucose supplementation nor free intake of mixed nutrients ameliorated the development of postoperative insulin resistance.

Postoperative delirium in elderly patients after major abdominal surgery.

BACKGROUND: The aim of this study was to investigate the occurrence of postoperative delirium (POD) in elderly patients undergoing major abdominal surgery and to identify factors associated with delirium in this population. METHODS: Data were collected prospectively from 51 patients aged 65 years or more. Delirium was diagnosed by the Confusion Assessment Method and from the medical records. The Mini Mental State Examination (MMSE) was used to identify cognitive impairment. RESULTS: POD occurred in 26 of 51 patients. Delirium lasted for 1-2 days in 14 patients (short POD group) and 3 days or more in 12 patients (long POD group). The latter patients had significantly greater intraoperative blood loss and intravenous fluid infusion, a higher rate of postoperative complications, a lower MMSE score on postoperative day 4 and a longer hospital stay than patients without POD. Patients in the short POD group were significantly older than those in the long POD group and those who did not develop delirium. CONCLUSION: Approximately half of the elderly patients in this study developed POD. Bleeding was found to be an important risk factor for delirium.

Chronically administered islet amyloid polypeptide in rats serves as an adiposity inhibitor and regulates energy homeostasis.

AIMS/HYPOTHESIS: Islet amyloid polypeptide (IAPP) reduces food intake and body weight in laboratory animals. In addition, IAPP appears to regulate nutrient metabolism. In the present studies, we investigated the effect of chronic IAPP treatment on different aspects of energy homeostasis. METHODS: IAPP was infused (25 pmol/kg/min) from subcutaneous osmotic pumps for 2-7 days. Rats in 2 saline-infused control groups were fed ad libitum (AF) or pair-fed (PF) against the IAPP-treated rats. RESULTS: As expected, the IAPP infusion reduced food intake and body weight gain. In addition, the IAPP treatment decreased the epididymal fat pad (vs. PF rats, p < 0.05) and lowered circulating levels of triglycerides (vs. PF rats, p < 0.05), free fatty acids (vs. PF rats, p < 0.05), leptin (vs. both AF and PF rats, p < 0.05) and insulin (vs. AF rats, p < 0.05). In contrast, glucose and protein metabolism in the IAPP-treated rats was largely unchanged, as shown in results regarding serum glucose, glucose transport in skeletal muscle, blood urea nitrogen, and glycogen and protein content in the liver and in skeletal muscle. CONCLUSION/INTERPRETATION: In summary, chronic IAPP exposure led to a changed lipid metabolism, which was characterized by decreased adiposity, hypolipidemia and hypoleptinemia, and to unchanged glucose and protein homeostasis. These results were similar to those seen in rodents during chronic exposure to another satiety/adiposity regulator, leptin. In conclusion, chronically administered IAPP plays a role as a satiety and adiposity signal in rats, and helps regulate energy homeostasis.

Measurement of the uptake of radioactive para-aminobenzoic acid monitors folate biosynthesis in Escherichia coli K-12.

This study was undertaken to develop a method for rapidly and easily estimating the folate content of different strains of Escherichia coli. Cells were grown to stationary phase in medium containing radioactive para-aminobenzoic acid. The amount of label incorporated into cells was measured by collecting the cells on a filter, washing, and then determining the radioactivity retained on the filter. The addition of unlabeled para-aminobenzoic acid or the antifolate drugs sulfathiazole or trimethoprim reduced the uptake of the radioactive compound. These results indicate that uptake measurements monitored folate biosynthesis. The assay is well suited for the analysis of large numbers of samples and does not require specialized equipment.

Kasugamycin inhibition of nonsense suppression by thymine-requiring strains of Escherichia coli K12.

Thymine-requiring strains of Escherichia coli suppress nonsense and frame-shift mutations. This appears to occur during translation, suggesting that the lack of activity of an enzyme thymidylate synthase, required for the synthesis of a DNA precursor, alters the fidelity of translation. The aminoglycoside antibiotic kasugamycin, which enhances translational accuracy in vitro, prevents thymine-requiring cells from suppressing. The inhibition of suppression by kasugamycin is not prevented by the introduction of two different kasugamycin-resistance mutations, although the dose required for inhibition increases. These observations support the conclusion that suppression occurs during translation.

Changes in translational accuracy of Escherichia coli when folate metabolism is perturbed.

Translational accuracy was monitored in Escherichia coli mutants which contain abnormal folate pools. A decrease in translational accuracy was indicated by the increased production of a T4 phage mutant containing a UGA mutation in a tail fibre gene. An E. coli folC mutant suppressed the phage mutant under conditions where it presumably accumulated methyl-tetrahydrofolate (methyl-THF). A UGA suppressor strain with the mutation affecting the primary structure of the tRNA(trp) normally suppressed the phage mutant. When the strain was made thymine-requiring it no longer suppressed. The accumulation of methyl-THF which permits suppression by thymine-requiring strains may act to interfere with suppression by the tRNA suppressor, possibly by changing the modification pattern of the tRNA.

Growth properties of a folA null mutant of Escherichia coli K12.

In Escherichia coli, dihydrofolate reductase is required for both the de novo synthesis of tetrahydrofolate and the recycling of dihydrofolate produced during the synthesis of thymidylate. The coding region of the dihydrofolate reductase gene, folA, was replaced with a kanamycin resistance determinant. Unlike earlier deletions, this mutation did not disrupt flanking genes. When the mutation was transferred into a wild-type strain and a thymidine-(thy) requiring strain, the resulting strains were viable but slow growing on rich medium. Both synthesized less folate than their parents, as judged by the incorporation of radioactive para-aminobenzoic acid. The derivative of the wild-type strain did not grow on any defined minimal media tested. In contrast, the derivative of the thy-requiring strain grew slowly on minimal medium with thy but exhibited auxotrophies on some combinations of supplements. These results suggest that when folates are limited, they can be distributed appropriately to folate-dependent biosynthetic reactions only under some conditions.