Utility of barium studies for patients with recurrent weight gain after Roux-en-Y gastric bypass.

AIM: To determine the utility of barium studies for detecting abnormalities responsible for recurrent weight gain after gastric bypass surgery. METHODS: A computerized search identified 42 patients who had undergone barium studies for recurrent weight gain after gastric bypass and 42 controls. The images were reviewed to determine the frequency of staple-line breakdown and measure the length/width of the pouch and gastrojejunal anastomosis. A large pouch exceeded 6 cm in length or 5 cm in width and a wide anastomosis exceeded 2 cm. Records were reviewed for the amount of recurrent weight gain and subsequent weight loss after additional treatment. RESULTS: Staple-line breakdown was present in 6/42 patients (14%) with recurrent weight gain. When measurements were obtained, 13/35 patients (37%) with recurrent weight gain had a large pouch, three (9%) had a wide anastomosis, and four (11%) had both, whereas 22/42 controls (52%) had a large pouch, one (2%) had a wide anastomosis, and two (5%) had both. Ten patients (24%) with recurrent weight gain underwent staple-line repair (n = 3) or pouch/anastomosis revision (n = 7). These 10 patients had a mean weight loss of 38.1 lbs versus a mean loss of 8.6 lbs in 19 patients managed medically. CONCLUSION: Only 14% of patients with recurrent weight gain after gastric bypass had staple-line breakdown, whereas 57% had a large pouch, wide anastomosis, or both. Not all patients with abnormal anatomy had recurrent weight gain, but those who did were more likely to benefit from surgical intervention than from medical management.

Comparison of infrared thermography and laser speckle contrast imaging for the dynamic assessment of digital microvascular function.

OBJECTIVES: Laser speckle contrast imaging (LSCI) is a novel non-invasive microvascular imaging modality. The present study evaluates the validity and reliability of LSCI by comparison with infrared thermography (IRT) for the dynamic assessment of digital microvascular function in healthy volunteers. METHODS: Subjects attended on 3 occasions. Simultaneous assessment of cutaneous perfusion at 3 distinct regions of interest (ROI) within the hands was undertaken using LSCI and infrared thermography (IRT) at baseline, and at 13s intervals over 15 min following a standardised local cold challenge. Endpoints for evaluation included absolute measurements at baseline and following cold stress, in addition to the characteristics of the re-warming curves (maximum % recovery and maximum gradient). Visits 1 and 2 were undertaken in identical conditions (ambient temperature 23°C) to assess reproducibility, whereas visit 3 was undertaken at a lower ambient room temperature of 18°C to evaluate responsiveness to reduction in ambient room temperature. RESULTS: Fourteen healthy participants completed the study. There was greater variability in the data generated using LSCI compared with the highly damped IRT, reflecting greater sensitivity of LSCI to physiological variation and movement artefact. LSCI and IRT correlated well at baseline and following cold challenge for all endpoints (r(s) for pooled data between 0.5 and 0.65, p<0.00005). Reproducibility of both IRT and LSCI was excellent (ICCs>0.75) for absolute assessments but lower for re-warming curve characteristics. LSCI provides greater spatial resolution than IRT identifying variation in cutaneous perfusion within the hands most likely associated with the presence of arteriovenous anastamoses. Both techniques were responsive to reduction in ambient room temperature. Effect sizes were greatest for IRT than LSCI (e.g. -1.17 vs. -0.85 at ROI 1 at baseline) although this may represent heat transfer rather than altered vascular perfusion. DISCUSSION: In the dynamic assessment of digital vascular perfusion, LSCI correlates well with IRT, is reproducible and responsive to reduction in ambient room temperature. Absolute measurements appear preferable to parameters derived from re-warming curve characteristics when assessing digital perfusion following cold challenge. The greater temporal and spatial resolution of LSCI compared with IRT may facilitate the development of novel assessment tools of autonomic function and digital cutaneous perfusion.

Temperature increase of 21st century mitigation scenarios.

Estimates of 21st Century global-mean surface temperature increase have generally been based on scenarios that do not include climate policies. Newly developed multigas mitigation scenarios, based on a wide range of modeling approaches and socioeconomic assumptions, now allow the assessment of possible impacts of climate policies on projected warming ranges. This article assesses the atmospheric CO(2) concentrations, radiative forcing, and temperature increase for these new scenarios using two reduced-complexity climate models. These scenarios result in temperature increase of 0.5-4.4 degrees C over 1990 levels or 0.3-3.4 degrees C less than the no-policy cases. The range results from differences in the assumed stringency of climate policy and uncertainty in our understanding of the climate system. Notably, an average minimum warming of approximately 1.4 degrees C (with a full range of 0.5-2.8 degrees C) remains for even the most stringent stabilization scenarios analyzed here. This value is substantially above previously estimated committed warming based on climate system inertia alone. The results show that, although ambitious mitigation efforts can significantly reduce global warming, adaptation measures will be needed in addition to mitigation to reduce the impact of the residual warming.

Forced and unforced ocean temperature changes in Atlantic and Pacific tropical cyclogenesis regions.

Previous research has identified links between changes in sea surface temperature (SST) and hurricane intensity. We use climate models to study the possible causes of SST changes in Atlantic and Pacific tropical cyclogenesis regions. The observed SST increases in these regions range from 0.32 degrees C to 0.67 degrees C over the 20th century. The 22 climate models examined here suggest that century-timescale SST changes of this magnitude cannot be explained solely by unforced variability of the climate system. We employ model simulations of natural internal variability to make probabilistic estimates of the contribution of external forcing to observed SST changes. For the period 1906-2005, we find an 84% chance that external forcing explains at least 67% of observed SST increases in the two tropical cyclogenesis regions. Model "20th-century" simulations, with external forcing by combined anthropogenic and natural factors, are generally capable of replicating observed SST increases. In experiments in which forcing factors are varied individually rather than jointly, human-caused changes in greenhouse gases are the main driver of the 20th-century SST increases in both tropical cyclogenesis regions.

Insulin gene transfer enhances the function of human islet grafts.

AIMS/HYPOTHESIS: Recent success in islet transplantation renews the hope for the complete cure of patients afflicted with Type 1 diabetes. However, in the Edmonton series, two to four pancreas donors were required to obtain a sufficient islet mass to reverse the diabetes of each patient. In view of the donor shortage, this represents a major obstacle preventing greater application of islet transplantation to diabetic patients. We hypothesised that increasing the expression of the insulin gene in transplanted islets would augment their capacity for insulin production, thereby allowing reversal of diabetes with a reduced islet mass. METHODS: We used a replication defective adenovirus to deliver the human proinsulin gene (Ad-Ins) to isolated human islets. The function of Ad-Ins-transduced human islets was compared to islets transduced with a control vector (Ad-lacz). RESULTS: Ad-Ins-transduced islets produced two to three times more insulin than normal islets or those infected with Ad-lacz, as assessed by in vitro perifusion tests of glucose stimulated insulin release. When transplanted, Ad-Ins-transduced islets normalised the blood glucose of diabetic immunodeficient NOD-Scid mice, and less than half as many Ad-Ins islets were required for reversal of diabetes than when normal islets were transplanted. CONCLUSION/INTERPRETATION: Our results suggest a simple and effective approach that could enhance the efficiency of islet transplantation for treatment of diabetes in humans.

Constitutive and regulated expression of processed insulin following in vivo hepatic gene transfer.

To test whether hepatocytes engineered in vivo can serve as surrogate beta cells by similarly secreting mature insulin in a glucose-sensitive manner, we prepared adenoviral vectors encoding wild-type proinsulin (hIns-wt), a modified proinsulin cleavable by the ubiquitously expressed protease furin (hIns-M3), or each of the two beta cell specific pro-insulin convertases PC2 and PC3. Following a detailed in vitro characterization of the proteins produced by our vectors, we infected the liver and, for comparison, the muscle of a chemically induced murine model of type I diabetes. Insulin expression from the transduced tissues was extensively characterized and showed to be constitutive rather than regulated. To obtain regulated expression, we placed expression of hIns-M3 under the control of the dimerizer-inducible transcription system. Hormone secretion from mouse liver was negligible in the absence of the dimerizer drug rapamycin, was inducible in a dose-dependent manner upon its administration, and reversible following drug withdrawal. These data confirm liver as a promising target for in vivo expression of processed insulin. While suggesting that hepatocytes cannot provide authentic glucose-responsive regulation, these results demonstrate that pharmacological regulation is a promising alternative route to the controlled delivery of insulin following hepatic gene transfer.

Adenoviral vector-mediated insulin gene transfer in the mouse pancreas corrects streptozotocin-induced hyperglycemia.

Therapy for type 1 diabetes consists of tight blood glucose (BG) control to minimize complications. Current treatment relies on multiple insulin injections or an insulin pump placement, beta-cell or whole pancreas transplantation. All approaches have significant limitations and have led to the realization that novel treatment strategies are needed. Pancreatic acinar cells have features that make them a good target for insulin gene transfer. They are not subject to autoimmune attack, a problem with pancreas or islets transplantation, they are avidly transduced by recombinant adenoviral vectors, and capable of exporting a variety of peptides into the portal circulation. Recombinant adenoviral vectors were engineered to express either wild-type or furin-modified human insulin cDNA (AdCMVhInsM). Immunodeficient mice were made diabetic with streptozotocin and injected intrapancreatically with the vectors. BG and blood insulin levels have normalized after administration of AdCMVhInsM. Immunohistochemistry and electron microscopy showed the presence of insulin in acinar cells throughout the pancreas and localization of insulin molecules to acinar cell vesicles. The data clearly establish a relationship between intrapancreatic vector administration, decreased BG and elevated blood insulin levels. The findings support the use of pancreatic acinar cells to express and secrete insulin into the blood stream.

Interpretation of high projections for global-mean warming.

The Intergovernmental Panel on Climate Change (IPCC) has recently released its Third Assessment Report (TAR), in which new projections are given for global-mean warming in the absence of policies to limit climate change. The full warming range over 1990 to 2100, 1.4 degrees to 5.8 degrees C, is substantially higher than the range given previously in the IPCC Second Assessment Report. Here we interpret the new warming range in probabilistic terms, accounting for uncertainties in emissions, the climate sensitivity, the carbon cycle, ocean mixing, and aerosol forcing. We show that the probabilities of warming values at both the high and low ends of the TAR range are very low. In the absence of climate-mitigation policies, the 90% probability interval for 1990 to 2100 warming is 1.7 degrees to 4.9 degrees C.

Activation of innate immunity in nonhuman primates following intraportal administration of adenoviral vectors.

The innate immune response to intraportally infused adenoviral vector was evaluated in rhesus monkeys. A first-generation adenovirus-expressing lacZ (Ad-lacZ) was administered at a dose just below that which causes severe morbidity. The response to vector was evaluated for the initial 24 h following infusion. Clinical findings during this time were primarily limited to petechiae, consistent with the development of thrombocytopenia and biochemical evidence of disseminated intravascular coagulation. Serum transaminases were elevated and a lymphopenia developed. Tracking of fluorescent-labeled vector demonstrated distribution to macrophages and dendritic cells of the spleen and Kupffer cells of the liver. A systemic release of the cytokine IL-6 occurred soon after vector infusion. Analysis of splenic cells revealed acute activation of macrophages and dendritic cells followed by massive apoptosis. Bone marrow cultures demonstrated normal erythroid and primitive progenitors with a significant decrease in myeloid progenitors. Similar findings, except the abnormality in bone marrow cultures, were observed in monkeys who received an identical dose of Ad-lacZ in which vector genes were inactivated with psoralen and UV irradiation. These data suggest that inadvertent targeting of antigen-presenting cells following intraportal infusion of vector leads to a systemic cytokine syndrome which may be triggered by the viral capsid proteins.

Genotype spectrum of ornithine transcarbamylase deficiency: correlation with the clinical and biochemical phenotype.

Ornithine transcarbamylase (OTC) deficiency, a partially dominant X-linked disorder, is the most common inherited defect of the urea cycle. Previous reports suggested a variable phenotypic spectrum, and several studies documented different "private" mutations in the OTC genes of patients. Our laboratory identified disease-causing mutations in 157 families with OTC deficiency, 100 of which came to medical attention through a hemizygous propositus and in 57 the index case was a heterozygous female. We correlated the genotype with age of onset, liver OTC activity, incorporation of nitrogen into urea, and peak plasma ammonia levels. The "neonatal onset" group has a homogeneous clinical and biochemical phenotype, whereas the "late onset" group shows an extremely wide phenotype; 60% of the mutations are associated exclusively with acute neonatal hyperammonemic coma. The remaining mutations caused a nonuniform phenotype ranging from severe disease to no symptoms; 31% of the mutations in the OTC gene occur in CpG dinucleotides (methylation-mediated deamination), and none of them accounted for more than 4% of the total. Eighty-six percent of the mutations represented single-base substitutions and 68% of the substitutions were transitions. G-to-A and C-to-T transitions were the most frequent substitutions (34 and 21%, respectively) whereas C-to-A, A-to-C, C-to-G, and T-to-A transversions were the least common (1.5-3%). Twenty percent of propositi and 77% of propositae carried new mutations. Forty percent of female germinal mutations were in CpG dinucleotides whereas this number appears much smaller in male germinal mutations. These data allow classification of patients with OTC deficiency into at least two groups who have discordant disease course and prognoses. In addition, they improve our understanding on the origin of mutations in the OTC gene and allow better counseling of affected families.

Readministration of adenovirus vector in nonhuman primate lungs by blockade of CD40-CD40 ligand interactions.

The interaction between CD40 on B cells and CD40 ligand (CD40L) on activated T cells is important for B-cell differentiation in T-cell-dependent humoral responses. We have extended our previous murine studies of CD40-CD40L in adenoviral vector-mediated immune responses to rhesus monkeys. Primary immune responses to adenoviral vectors and the ability to readminister vector were studied in rhesus monkeys in the presence or absence of a transient treatment with a humanized anti-CD40 ligand antibody (hu5C8). Adult animals were treated with hu5C8 at the time vector was instilled into the lung. Immunological analyses demonstrated suppression of adenovirus-induced lymphoproliferation and cytokine responses (interleukin-2 [IL-2], gamma interferon, IL-4, and IL-10) in hu5C8-treated animals. Animals treated with hu5C8 secreted adenovirus-specific immunoglobulin M (IgM) levels comparable to control animals, but did not secrete IgA or develop neutralizing antibodies; consequently, the animals could be readministered with adenovirus vector expressing alkaline phosphatase. A second study was designed to examine the long-term effects on immune functions of a short course of hu5C8. Acute hu5C8 treatment resulted in significant and prolonged inhibition of the adenovirus-specific humoral response well beyond the time hu5C8 effects were no longer significant. These studies demonstrate the potential of hu5C8 as an immunomodulatory regimen to enable administration of adenoviral vectors, and they advocate testing this model in humans.

Acute pancreatitis secondary to dehydration: case report and review of the literature.

Recent reports have documented the potentially catastrophic consequences of dehydration induced by vigorous exercise in otherwise healthy individuals. A case of acute pancreatitis secondary to exercise-induced dehydration is presented, and the literature of dehydration-induced syndromes, both research and clinical, is reviewed. The goal of this case report is to heighten awareness of dehydration as a potential cause of acute pancreatitis.

Gene transfer into the liver of nonhuman primates with E1-deleted recombinant adenoviral vectors: safety of readministration.

Preclinical studies were designed to investigate the safety of recombinant adenoviruses infused into the portal vein of adult rhesus monkeys, as well as the safety and efficacy of readministration of these agents. The vectors used were recombinant adenoviruses, the E1 region of which was replaced with a marker gene expression cassette. Four 3- to 5-kg rhesus monkeys underwent portal vein cannulation, and infusion of escalating doses of recombinant first-generation vector. Serial sequential liver biopsies were performed, and necropsies were performed out to 14 months. X-Gal histochemical analysis of the liver showed evidence of dose-dependent increased gene transfer throughout the liver. Quantitative analysis of histopathology showed that portal inflammation was also present in transduced livers, and occurred in a dose-dependent manner. Severe toxicity, including mortality, was noted at the highest dose of vector. Readministration of a second vector was associated with the same degree of toxicity as the first vector, but prompted a much more vigorous neutralizing antibody response. The data suggest that intraportal administration and readministration of recombinant adenoviral E1-deleted vectors are feasible and safe. Vector administration at the highest dose (1 x 10(13) particles/kg) was associated with severe clinical and biochemical toxicity, and significant gene expression was associated with transaminitis. Readministration of vector is safe, but gene transfer is limited by the presence of neutralizing antibody.

Cell-biological assessment of human glucokinase mutants causing maturity-onset diabetes of the young type 2 (MODY-2) or glucokinase-linked hyperinsulinaemia (GK-HI).

Mutations in the glucokinase (GK) gene cause type-2 maturity-onset diabetes of the young type 2 (MODY-2) and GK-linked hyperinsulinaemia (GK-HI). Recombinant adenoviruses expressing the human wild-type islet GK or one of four mutant forms of GK, (the MODY-2 mutants E70K, E300K and V203A and the GK-HI mutant V455M) were transduced into glucose-responsive insulin-secreting beta-HC9 cells and tested functionally in order to initiate the first analysis in vivo of recombinant wild-type and mutant human islet GK. Kinetic analysis of wild-type human GK showed that the glucose S(0. 5) and Hill coefficient were similar to previously published data in vitro (S(0.5) is the glucose level at the half-maximal rate). E70K had half the glucose affinity of wild-type, but similar enzyme activity. V203A demonstrated decreased catalytic activity and an 8-fold increase in glucose S(0.5) when compared with wild-type human islet GK. E300K had a glucose S(0.5) similar to wild-type but a 10-fold reduction in enzyme activity. E300K mRNA levels were comparable with wild-type GK mRNA levels, but Western-blot analyses demonstrated markedly reduced levels of immunologically detectable protein, consistent with an instability mutation. V455M was just as active as wild-type GK, but with a markedly reduced S(0.5). The effects of the different GK mutants on glucose-stimulated insulin release support the kinetic and expression data. These experiments show the utility of a combined genetic, biochemical and cell-biological approach to the quantification of functional and structural changes of human GK that result from MODY-2 and GK-HI mutations.

Repeated administration of adenoviral vectors in lungs of human CD4 transgenic mice treated with a nondepleting CD4 antibody.

The central role of CD4+ T cells in regulation of adenovirus vector-mediated immune responses has been documented previously in murine models. We analyzed the effects of a nondepleting mAb to human CD4 (CD4 mAb; Clenoliximab) on immune functions following intratracheal administration of adenoviral vectors in murine CD4-deficient mice (muCD4KO) expressing a human CD4 transgene (HuCD4 mice). Treatment of HuCD4 mice with Clenoliximab inhibited both cell-mediated and humoral immune responses to adenoviral Ags. Chronic treatment of HuCD4 mice with Clenoliximab permitted successful readministration of adenoviral vectors at least four times. The ability to readminister these vectors is associated with marked suppression of neutralizing Ab responses to viral capsid proteins. Clenoliximab also inhibited CTL and prolonged expression of the transgene. T or B cell responses to adenovirus did not emerge after the effects of a short course of Clenoliximab diminished. These data illustrate the potential utility of a nondepleting CD4 Ab in facilitating gene therapy using adenoviral vectors.

Phenobarbital in comparison with carbon tetrachloride and phenobarbital-induced cirrhosis in rat liver regeneration.

BACKGROUND: The simultaneous administration of carbon tetrachloride (CCl4) and phenobarbital in the rat produces one of the most common experimental models of liver cirrhosis. As phenobarbital also has a hepatotrophic effect, its role in liver regeneration following partial hepatectomy (HTX) is not elucidated. PURPOSE: To examine the effect of long-term administration of phenobarbital in liver regeneration after HTX with regard to CCl4-induced cirrhotic rat model. Materials and Methods. The liver regeneration following HTX in phenobarbital-treated rats (PB rats) was compared to that seen in cirrhotic rats (LC rats), induced by oral gavage of CCl4 and phenobarbital, and normal rats. The effect of the withdrawal of phenobarbital was also examined. Liver regeneration was estimated 24 h after the HTX by measuring the liver weight, the DNA content in the liver, and [3H]thymidine incorporation into the DNA. RESULTS: Treatment with CCl4 and phenobarbital caused liver deformity, and the highest percentage of liver weight regeneration was seen in LC rats with this deformity, even though [3H]thymidine incorporation into the DNA was impaired in this group. Phenobarbital had a hepatotrophic effect, but its withdrawal caused a decrease in liver mass and cessation of body weight gain. The change in the DNA content 24 h after HTX was negative in PB rats. CONCLUSIONS: Liver regeneration could not be estimated using liver or body weight in the PB or LC rat model. [3H]Thymidine incorporation into the DNA was reliable indicator of liver regeneration in the different liver states during the early stage after HTX. Although the DNA content with respect to total liver mass was obscured due to liver inflation in PB rats, [3H]thymidine incorporation into the DNA between PB rats and normal rats was similar.