Effect of a single dose of tobramycin on systemic inflammatory response-induced acute kidney injury in a 6-hour porcine model*

OBJECTIVE:: To evaluate whether the addition of tobramycin further compromises renal function in inflammatory response-induced acute kidney injury. Effective antibiotic treatment in septic shock is crucial for the outcome. The combination of aminoglycosides with different beta-lactam antibiotics offers a broad antimicrobial coverage, rapid bacterial killing, synergistic effects, and low antibiotic-induced endotoxin release. However, aminoglycosides have nephrotoxic effects that may aggravate sepsis-induced acute kidney injury. DESIGN:: Prospective, randomized, placebo-controlled experimental study. SETTING:: University research unit. SUBJECTS:: Twenty-four healthy pigs. INTERVENTIONS:: The animals were anesthetized and randomized to four groups. Groups I (n = 8) and II (n = 8) received endotoxin infusion for 6 hrs, whereas groups III (n = 4) and IV (n = 4) received saline. Groups I and III received 7 mg/kg of tobramycin 20 mins after the initiation of the protocol, whereas groups II and IV received saline. MEASUREMENTS AND MAIN RESULTS:: The renal elimination rate of a bolus dose of cefuroxime was chosen as the primary end point. Renal function was also evaluated by urine output, creatinine clearance, plasma cystatin C, plasma urea, and urine NAG (N-acetyl-beta-D-glucoaminidase). After 3 hrs, there were significantly lower cefuroxime elimination rates in the two endotoxin groups than in the nonendotoxin groups. No difference in cefuroxime elimination rates between groups I and II could be detected at any time point. Similarly, there were changes indicating acute kidney injury in urine output, creatinine clearance, and plasma cystatin C in the endotoxin groups with no differences between groups I and II. Plasma urea and urine NAG did not differ between any of the groups. CONCLUSIONS:: The result of this study does not lend any support to the hypothesis that a single dose of tobramycin enhances the risk of acute renal failure in cases with systemic inflammatory response-induced acute kidney injury

Enterovirus infection of human islets of Langerhans affects beta-cell function resulting in disintegrated islets, decreased glucose stimulated insulin secretion and loss of Golgi structure

Aims/hypothesis: In type 1 diabetes (T1D), most insulin-producing beta cells are destroyed, but the trigger is unknown. One of the possible triggers is a virus infection and the aim of this study was to test if enterovirus infection affects glucose stimulated insulin secretion and the effect of virus replication on cellular macromolecules and organelles involved in insulin secretion. Methods: Isolated human islets were infected with different strains of coxsackievirus B (CVB) virus and the glucose-stimulated insulin release (GSIS) was measured in a dynamic perifusion system. Classical morphological electron microscopy, large-scale electron microscopy, so-called nanotomy, and immunohistochemistry were used to study to what extent virus-infected beta cells contained insulin, and real-time PCR was used to analyze virus induced changes of islet specific genes. Results: In islets infected with CVB, GSIS was reduced in correlation with the degree of virus-induced islet disintegration. The expression of the gene encoding insulin was decreased in infected islets, whereas the expression of glucagon was not affected. Also, in islets that were somewhat disintegrated, there were uninfected beta cells. Ultrastructural analysis revealed that virus particles and virus replication complexes were only present in beta cells. There was a significant number of insulin granules remaining in the virus-infected beta cells, despite decreased expression of insulin mRNA. In addition, no typical Golgi apparatus was detected in these cells. Exposure of islets to synthetic dsRNA potentiated glucose-stimulated insulin secretion. Conclusions/interpretation: Glucose-stimulated insulin secretion; organelles involved in insulin secretion and gene expression were all affected by CVB replication in beta cells

Vaccination against the extra domain-B of fibronectin as a novel tumor therapy

Monoclonal antibody-based therapies have made an important contribution to current treatment strategies for cancer and autoimmune disease. However, the cost for these new drugs puts a significant strain on the health-care economy, resulting in limited availability for patients. Therapeutic vaccination, defined as induction of immunity against a disease-related self-molecule, is therefore an attractive alternative. To analyze the potential of such an approach, we have developed a vaccine against the extra domain-B (ED-B) of fibronectin. This 91-aa domain, inserted by alternative splicing, is expressed during vasculogenesis in the embryo, but essentially undetectable under normal conditions in the adult. However, ED-B is highly expressed around angiogenic vasculature, such as in tumorigenesis. Here, we demonstrate that it is possible to break self-tolerance and induce a strong antibody response against ED-B by vaccination. Nineteen of 20 vaccinated mice responded with production of anti-ED-B antibodies and displayed a 70% reduction in tumor size compared to those lacking anti-ED-B antibodies. Analysis of the tumor tissue revealed that immunization against ED-B induced several changes, consistent with an attack by the immune system. These data show that tumor vascular antigens are highly interesting candidates for development of therapeutic vaccines targeting solid tumors

Serglycin proteoglycan is required for secretory granule integrity in mucosal mast cells

SG (serglycin) PGs (proteoglycans) are strongly implicated in the assembly of MC (mast cell) granules. However, this notion has mainly been on the basis of studies of MCs of the connective tissue subtype, whereas the role of SG PG in mucosal MCs has not been explored. In the present study, we have addressed the latter issue by using mice with an inactivated SG gene. Bone marrow cells were differentiated in vitro into the mucosal MC phenotype, expressing the markers mMCP (mouse MC protease) -1 and -2. Biosynthetic labelling experiments performed on these cells revealed an ∼80% reduction of (35)SO(4)(2−) incorporation into PGs recovered from SG(−/−) cells as compared with SG(+/+) counterparts, indicating that SG is the dominating cell-associated PG of mucosal MCs. Moreover, the absence of SG led to defective metachromatic staining of mucosal MCs, both in vivo and in the in vitro-derived mucosal MCs. Ultrastructural analysis showed that granules were present in similar numbers in SG(+/+) and SG(−/−) cells, but that their morphology was markedly affected by the absence of SG, e.g. with electron-dense core formation only seen in SG(+/+) granules. Analysis of the MC-specific proteases showed that mMCP-1 and mMCP-7 were completely independent of SG for storage, whereas mMCP-2 showed a partial dependence. In contrast, mMCP-4 and -6, and carboxypeptidase A were strongly dependent on SG for storage. Together, our data indicate that SG PG is of crucial importance for assembly of mature mucosal MC granules, but that the specific dependence on SG for storage varies between individual granule constituents