Vasopressin in septic shock: effects on pancreatic, renal, and hepatic blood flow

INTRODUCTION: Vasopressin has been shown to increase blood pressure in catecholamine-resistant septic shock. The aim of this study was to measure the effects of low-dose vasopressin on regional (hepato-splanchnic and renal) and microcirculatory (liver, pancreas, and kidney) blood flow in septic shock. METHODS: Thirty-two pigs were anesthetized, mechanically ventilated, and randomly assigned to one of four groups (n = 8 in each). Group S (sepsis) and group SV (sepsis/vasopressin) were exposed to fecal peritonitis. Group C and group V were non-septic controls. After 240 minutes, both septic groups were resuscitated with intravenous fluids. After 300 minutes, groups V and SV received intravenous vasopressin 0.06 IU/kg per hour. Regional blood flow was measured in the hepatic and renal arteries, the portal vein, and the celiac trunk by means of ultrasonic transit time flowmetry. Microcirculatory blood flow was measured in the liver, kidney, and pancreas by means of laser Doppler flowmetry. RESULTS: In septic shock, vasopressin markedly decreased blood flow in the portal vein, by 58% after 1 hour and by 45% after 3 hours (p < 0.01), whereas flow remained virtually unchanged in the hepatic artery and increased in the celiac trunk. Microcirculatory blood flow decreased in the pancreas by 45% (p < 0.01) and in the kidney by 16% (p < 0.01) but remained unchanged in the liver. CONCLUSION: Vasopressin caused marked redistribution of splanchnic regional and microcirculatory blood flow, including a significant decrease in portal, pancreatic, and renal blood flows, whereas hepatic artery flow remained virtually unchanged. This study also showed that increased urine output does not necessarily reflect increased renal blood flow.

Streptozotocin-induced diabetes mellitus in pigs

We induced, as a precondition for a pancreas transplant, insulin-dependent diabetes mellitus in 67 Yorkshire Landrace pigs by administering streptozotocin. A dosage of 150 mg/kg body weight gave rise to a long-lasting diabetes mellitus that persisted with time (follow-up period: 26 weeks). Consecutive measurements of serum glucose and plasma insulin, before and up to 30 hours after administering streptozotocin, revealed triphasic behavior: initial hyperglycemia (1st to 3rd hour), pronounced hypoglycemia (12th to 18th hour), then hyperglycemia (22nd hour on). IVGTTs done 1 to 7 days after administering streptozotocin revealed a reduction of the K-value (glucose disappearance rate) from 0.3 (day 2) to 0.07 (day 4). Immunohistochemical studies revealed a complete loss of all beta-cells, concomitantly with a relative increase in glucagon- and somatostatin-positive cells. We also observed a complete loss of pp (pancreatic polypeptide)-positive cells. Diabetes induced by streptozotocin at 150 mg/kg body weight is complete and permanent; our mortality rate was 0%. Given the high morbidity rate after pancreatectomy, streptozotocin should be the method of choice for inducing diabetes mellitus in pigs.

CT data-based navigation for post-mortem biopsy-a feasibility study

INTRODUCTION: Recent advances in medical imaging have brought post-mortem minimally invasive computed tomography (CT) guided percutaneous biopsy to public attention. AIMS: The goal of the following study was to facilitate and automate post-mortem biopsy, to suppress radiation exposure to the investigator, as may occur when tissue sampling under computer tomographic guidance, and to minimize the number of needle insertion attempts for each target for a single puncture. METHODS AND MATERIALS: Clinically approved and post-mortem tested ACN-III biopsy core needles (14 gauge x 160 mm) with an automatic pistol device (Bard Magnum, Medical Device Technologies, Denmark) were used for probe sampling. The needles were navigated in gelatine/peas phantom, ex vivo porcine model and subsequently in two human bodies using a navigation system (MEM centre/ISTB Medical Application Framework, Marvin, Bern, Switzerland) with guidance frame and a CT (Emotion 6, Siemens, Germany). RESULTS: Biopsy of all peas could be performed within a single attempt. The average distance between the inserted needle tip and the pea centre was 1.4mm (n=10; SD 0.065 mm; range 0-2.3 mm). The targets in the porcine liver were also accurately punctured. The average of the distance between the needle tip and the target was 0.5 mm (range 0-1 mm). Biopsies of brain, heart, lung, liver, pancreas, spleen, and kidney were performed on human corpses. For each target the biopsy needle was only inserted once. The examination of one body with sampling of tissue probes at the above-mentioned locations took approximately 45 min. CONCLUSIONS: Post-mortem navigated biopsy can reliably provide tissue samples from different body locations. Since the continuous update of positional data of the body and the biopsy needle is performed using optical tracking, no control CT images verifying the positional data are necessary and no radiation exposure to the investigator need be taken into account. Furthermore, the number of needle insertions for each target can be minimized to a single one with the ex vivo proven adequate accuracy and, in contrast to conventional CT guided biopsy, the insertion angle may be oblique. Navigation for minimally invasive tissue sampling is a useful addition to post-mortem CT guided biopsy.

[Knowledge, attitude and reservations of medical students about organ transplantation: results of a survey during the first year of study]

AIM: Establish a list of first year medical students' attitudes, doubts, and knowledge in the fields of organ transplantation and donation. METHOD: Anonymized questionnaire handed out to students during class lectures. RESULTS: 183 questionnaires were distributed and 117 returned (participation: 64%). The average age of the students was 21.6 +/- 2.7 years (range 18 to 38 years); the sample included 71 women (60.7%) and 48 men (39.3%). Only 2 students (2%) were not interested in the subject of organ donation. The students knew very little of the legal aspects of organ donation and 1/4 of them thought there was even a Federal law regarding organ transplantation. When asked if they knew whether a law existed in the Canton of Berne, 44% replied yes, but only 24 (20%) knew that this is contradictory. There was no gender difference in the answers to these question. From 57 students (48%) 246 individual comments on doubts and concerns were analyzed. In this respect, the students mainly questioned whether the donor was truly dead when donation took place (n = 48), if illegal transplantation could be eliminated (n = 44) and if transplantation was truly necessary (n = 43). Some also mentioned religious/ethical doubts (n = 42). In regard to organ donation by a living individual, 27 students were concerned about the health of this donor. 20 students had doubts regarding the pressure possibly applied by family members and friends and as many voiced doubts in regard to premature diagnosis of brain death of potential donors. Only 2 students were concerned about the post-mortem presentation. 45 students (48%) indicated discomfort with the donation of certain organs. They ranked the kidney as the first organ to donate, followed by the pancreas, heart, cornea, intestine, lung and liver. CONCLUSION: The interest in organ donation and transplantation is already strong in fist year medical students in the pre-clinical stage. However, differences from lay public are not readably detectable at this stage of medical training. Adequate information could influence future physicians in their mediatory role.

Expression and hypoxic regulation of the endothelin system in endocrine cells of human and rat pancreatic islets

CONTEXT: The success of pancreatic islet transplantation depends largely on the capacity of the islet graft to survive the initial phase immediately after transplantation until revascularization is completed. Endothelin-1 (ET-1) is a strong vasoconstrictor which has been involved in solid organ graft failure but is also known to be a potent mitogenic/anti-apoptotic factor which could also potentially enhance the survival of the transplanted islets. OBJECTIVE: Characterization of the endothelin system with regard to a potential endothelin agonist/antagonist treatment. DESIGN: Regulated expression of the endothelin system in human and rat pancreatic islets and beta-cell lines was assessed by means of immunohistochemistry, competition binding studies, western blot, RT-PCR, real-time PCR and transplant studies. RESULTS: ET-1, ETA- and ETB-receptor immunoreactivity was identified in the endocrine cells of human and rat pancreatic islets. The corresponding mRNA was detectable in rat beta-cell lines and isolated rat and human pancreatic islets. Competition binding studies on rat islets revealed binding sites for both receptor types. ET-1 stimulated the phosphorylation of mitogen-activated protein kinase, which was prevented by ETA- and ETB-receptor antagonists. After exposure to hypoxia equal to post-transplant environment oxygen tension, mRNA levels of ET-1 and ETB-receptor of human islets were robustly induced whereas ETA-receptor mRNA did not show significant changes. Immunostaining signals for ET-1 and ETA-receptor of transplanted rat islets were markedly decreased when compared to native pancreatic sections. CONCLUSIONS: In pancreatic islets, ET-1 and its receptors are differentially expressed by hypoxia and after transplantation. Our results provide the biological basis for the study of the potential use of endothelin agonists/antagonists to improve islet transplantation outcome.

Tmem27: a cleaved and shed plasma membrane protein that stimulates pancreatic beta cell proliferation

The signals and molecular mechanisms that regulate the replication of terminally differentiated beta cells are unknown. Here, we report the identification and characterization of transmembrane protein 27 (Tmem27, collectrin) in pancreatic beta cells. Expression of Tmem27 is reduced in Tcf1(-/-) mice and is increased in islets of mouse models with hypertrophy of the endocrine pancreas. Tmem27 forms dimers and its extracellular domain is glycosylated, cleaved and shed from the plasma membrane of beta cells. This cleavage process is beta cell specific and does not occur in other cell types. Overexpression of full-length Tmem27, but not the truncated or soluble protein, leads to increased thymidine incorporation, whereas silencing of Tmem27 using RNAi results in a reduction of cell replication. Furthermore, transgenic mice with increased expression of Tmem27 in pancreatic beta cells exhibit increased beta cell mass. Our results identify a pancreatic beta cell transmembrane protein that regulates cell growth of pancreatic islets.

Reduced beta-cell mass and altered glucose sensing impair insulin-secretory function in betaIRKO mice

Pancreatic beta-cell-restricted knockout of the insulin receptor results in hyperglycemia due to impaired insulin secretion, suggesting that this cell is an important target of insulin action. The present studies were undertaken in beta-cell insulin receptor knockout (betaIRKO) mice to define the mechanisms underlying the defect in insulin secretion. On the basis of responses to intraperitoneal glucose, approximately 7-mo-old betaIRKO mice were either diabetic (25%) or normally glucose tolerant (75%). Total insulin content was profoundly reduced in pancreata of mutant mice compared with controls. Both groups also exhibited reduced beta-cell mass and islet number. However, insulin mRNA and protein were similar in islets of diabetic and normoglycemic betaIRKO mice compared with controls. Insulin secretion in response to insulin secretagogues from the isolated perfused pancreas was markedly reduced in the diabetic betaIRKOs and to a lesser degree in the nondiabetic betaIRKO group. Pancreatic islets of nondiabetic betaIRKO animals also exhibited defects in glyceraldehyde- and KCl-stimulated insulin release that were milder than in the diabetic animals. Gene expression analysis of islets revealed a modest reduction of GLUT2 and glucokinase gene expression in both the nondiabetic and diabetic mutants. Taken together, these data indicate that loss of functional receptors for insulin in beta-cells leads primarily to profound defects in postnatal beta-cell growth. In addition, altered glucose sensing may also contribute to defective insulin secretion in mutant animals that develop diabetes.

Highly efficient in vivo agonist-induced internalization of sst2 receptors in somatostatin target tissues

The successful peptide receptor imaging of tumors, as exemplified for somatostatin receptors, is based on the overexpression of peptide receptors in selected tumors and the high-affinity binding to these tumors of agonist radioligands that are subsequently internalized into the tumor cells in which they accumulate. Although in vitro studies have shown ample evidence that the ligand-receptor complex is internalized, in vivo evidence of agonist-induced internalization of peptide receptors, such as somatostatin receptors, is missing. METHODS: Rats subcutaneously transplanted with the somatostatin receptor subtype 2 (sst(2))-expressing AR42J tumor cells were treated with intravenous injections of various doses of the sst(2) agonist [Tyr(3), Thr(8)]-octreotide (TATE) or of the sst(2) antagonist 1,4,7,10-tetraazacyclododecane-N,N',N'',N''',-tetraacetic acid (DOTA)-Bass and were sacrificed at various times ranging from 2.5 min to 24 h after injection. The tumors and pancreas were then removed from each animal. All tissue samples were processed for sst(2) immunohistochemistry using sst(2)-specific antibodies. RESULTS: Compared with the sst(2) receptors in untreated animals, which localized at the plasma membrane in pancreatic and AR42J tumor cells, the sst(2) receptors in treated animals are detected intracellularly after an intravenous injection of the agonist TATE. Internalization is fast, as the receptors are already internalizing 2.5 min after TATE injection. The process is extremely efficient, as most of the cell surface receptors internalize into the cell and are found in endosomelike structures after TATE injection. The internalization is most likely reversible, because 24 h after injection the receptors are again found at the cell surface. The process is also agonist-dependent, because internalization is seen with high-affinity sst(2) agonists but not with high-affinity sst(2) antagonists. The same internalization properties are seen in pancreatic and AR42J tumor cells. They can further be confirmed in vitro in human embryonic kidney-sst(2) cells, with an immunofluorescence microscopy-based sst(2) internalization assay. CONCLUSION: These animal data strongly indicate that the process of in vivo sst(2) internalization after agonist stimulation is fast, extremely efficient, and fully functional under in vivo conditions in neoplastic and physiologic sst(2) target tissues. This molecular process is, therefore, likely to be responsible for the high and long-lasting uptake of sst(2) radioligands seen in vivo in sst(2)-expressing tumors.

Pancreatic stone protein is highly increased during posttraumatic sepsis and activates neutrophil granulocytes

OBJECTIVES: The level of pancreatic stone protein/regenerating protein (PSP/reg), a secretory protein produced in the pancreas, increases dramatically during pancreatic disease. However, after stress (e.g., anesthesia), PSP/reg levels are increased transiently in animals without pancreatic injury. Therefore, we aimed to determine whether PSP/reg is an acute-phase protein after nonpancreatic trauma. PATIENTS: Eighty-three polytraumatic patients without pancreatic damage. MEASUREMENTS AND MAIN RESULTS: We compared serum PSP/reg levels from polytraumatic patients without pancreatic damage with those in healthy controls (n = 38). C-reactive protein, interleukin-6, procalcitonin, and leukocyte numbers were also compared. The expression of CD62L and CD11b on neutrophils after exposure to PSP/reg was analyzed by flow cytometry. Thirty-three patients (39%) developed sepsis, 32 (38%) had local infections, and 18 (21%) had no infections. At admission, PSP/reg serum levels (10.2 [6.2-14.5] ng/mL; median [interquartile range]) were comparable with those in healthy controls (10.4 [7.5-12.3] ng/mL). During hospital stay, PSP/reg levels were elevated significantly in patients with sepsis (146.4 ng/mL) and in patients with infections (111.4 ng/mL) compared with patients without infections (22.8 ng/mL). Furthermore, binding of fluorescein isothiocyanate-labeled recombinant PSP/reg to human neutrophils was demonstrated. Recombinant PSP/reg elicited a dose-dependent shedding of L-selectin (CD62L) and upregulation of beta2-integrin (CD11b) in neutrophils, which indicates that PSP/reg activates neutrophils. CONCLUSIONS: We conclude that PSP/reg is up-regulated in blood after trauma, and the PSP/reg level is related to the severity of inflammation. Furthermore, PSP/reg binds to and activates neutrophils. Therefore, PSP/reg might be an acute-phase protein that could serve as a marker for posttraumatic complications.

Phenotypic associations of Crohn's disease with antibodies to flagellins A4-Fla2 and Fla-X, ASCA, p-ANCA, PAB, and NOD2 mutations in a Swiss Cohort

BACKGROUND: Distinct Crohn's disease (CD) phenotypes correlate with antibody reactivity to microbial antigens. We examined the association between antibody response to 2 new flagellins called A4-Fla2 and Fla-X, anti-Saccharomyces cerevisiae antibodies (ASCA), anti-neutrophil cytoplasmic antibodies (p-ANCA), anti-pancreas antibodies (PAB), NOD2 mutations (R702W, G908R, and L1007fsinsC), and clinical CD phenotypes (according to Vienna criteria). METHODS: All the above-mentioned antibodies as well as NOD2 mutations were determined in 252 CD patients, 53 with ulcerative colitis (UC), and 43 healthy controls (HC) and correlated with clinical data. RESULTS: A seroreactivity for A4-Fla2/Fla-X/ASCA/p-ANCA/PAB (in percent) was found in 59/57/62/12/22 of CD patients, 6/6/4/51/0 of UC patients, and 0/2/5/0/0 of healthy controls. CD behavior: 37% B1, 36% B2, and 27% B3. In multivariate logistic regression, antibodies to A4-Fla2, Fla-X, and ASCA were significantly associated with stricturing phenotype (P = 0.027, P = 0.041, P < 0.001), negative associations were found with inflammatory phenotype (P = 0.001, P = 0.005, P < 0.001). Antibodies to A4-Fla2, Fla-X, ASCA, and NOD2 mutations were significantly associated with small bowel disease (P = 0.013, P = 0.01, P < 0.001, P = 0.04), whereas ASCA was correlated with fistulizing disease (P = 0.007), and small bowel surgery (P = 0.009). Multiple antibody responses against microbial antigens were associated with stricturing (P < 0.001), fistulizing disease (P = 0.002), and small bowel surgery (P = 0.002). CONCLUSIONS: Anti-flagellin antibodies and ASCA are strongly associated with complicated CD phenotypes. CD patients with serum reactivity against multiple microbes have the greatest frequency of strictures, perforations, and small bowel surgery. Further prospective longitudinal studies are needed to show that antibody-based risk stratification improves the clinical outcome of CD patients.

The murine Fgfrl1 receptor is essential for the development of the metanephric kidney

Fgfrl1 is a novel member of the fibroblast growth factor receptor family. Its extracellular domain resembles the four conventional Fgfrs, while its intracellular domain lacks the tyrosine kinase domain necessary for Fgf mediated signal transduction. During embryonic development Fgfrl1 is expressed in the musculoskeletal system, in the lung, the pancreas and the metanephric kidney. Targeted disruption of the Fgfrl1 gene leads to the perinatal death of the mice due to a hypoplastic diaphragm, which is unable to inflate the lungs. Here we show that Fgfrl1-/- embryos also fail to develop the metanephric kidney. While the rest of the urogenital system, including bladder, ureter and sexual organs, develops normally, a dramatic reduction of ureteric branching morphogenesis and a lack of mesenchymal-to-epithelial transition in the nephrogenic mesenchyme result in severe renal dysgenesis. The failure of nephron induction might be explained by the absence of the tubulogenic markers Wnt4, Fgf8, Pax8 and Lim1 at E12.5 of the mutant animals. We also observed a loss of Pax2 positive nephron precursor cells and an increase of apoptosis in the cortical zone of the remnant kidney. Fgfrl1 is therefore essential for mesenchymal differentiation in the early steps of nephrogenesis.

Retinoic acid signaling organizes endodermal organ specification along the entire antero-posterior axis

BACKGROUND: Endoderm organ primordia become specified between gastrulation and gut tube folding in Amniotes. Although the requirement for RA signaling for the development of a few individual endoderm organs has been established a systematic assessment of its activity along the entire antero-posterior axis has not been performed in this germ layer. METHODOLOGY/PRINCIPAL FINDINGS: RA is synthesized from gastrulation to somitogenesis in the mesoderm that is close to the developing gut tube. In the branchial arch region specific levels of RA signaling control organ boundaries. The most anterior endoderm forming the thyroid gland is specified in the absence of RA signaling. Increasing RA in anterior branchial arches results in thyroid primordium repression and the induction of more posterior markers such as branchial arch Hox genes. Conversely reducing RA signaling shifts Hox genes posteriorly in endoderm. These results imply that RA acts as a caudalizing factor in a graded manner in pharyngeal endoderm. Posterior foregut and midgut organ primordia also require RA, but exposing endoderm to additional RA is not sufficient to expand these primordia anteriorly. We show that in chick, in contrast to non-Amniotes, RA signaling is not only necessary during gastrulation, but also throughout gut tube folding during somitogenesis. Our results show that the induction of CdxA, a midgut marker, and pancreas induction require direct RA signaling in endoderm. Moreover, communication between CdxA(+) cells is necessary to maintain CdxA expression, therefore synchronizing the cells of the midgut primordium. We further show that the RA pathway acts synergistically with FGF4 in endoderm patterning rather than mediating FGF4 activity. CONCLUSIONS/SIGNIFICANCE: Our work establishes that retinoic acid (RA) signaling coordinates the position of different endoderm organs along the antero-posterior axis in chick embryos and could serve as a basis for the differentiation of specific endodermal organs from ES cells.

[Imaging for hepato-pancreatico-biliary diseases - a short review]

The purpose of this chapter is to give a practical and clinically-orientated overview over the best radiological imaging for the most frequent diseases of the hepato-pancreatico-biliary system. For this purpose the liver parenchyma, the biliary tree, the pancreas and the hepatic vasculature are dealt with separately. According to the presumed pathology, the most cost-saving and time-efficient radiological imaging can then be chosen.

[Odynophagia of a young mother]

We report the case of a 34-year old mother presenting in the emergency unit because of fever and odynophagia. Herpetic esophagitis with Herpes simplex virus primoinfection in a immunocompetent patient was diagnosed. The virus was transmitted by her own child which came to be hospitalised because of herpetic stomatitis. In the blood chemistry pancreas enzymes were elevated which we interpreted as herpetic pancreatitis because of coincidence with herpetic esophagitis.