Laparoscopic sleeve gastrectomy improves renal transplant candidacy and posttransplant outcomes in morbidly obese patients.

Morbid obesity is a barrier to kidney transplantation due to inferior outcomes, including higher rates of new-onset diabetes after transplantation (NODAT), delayed graft function (DGF), and graft failure. Laparoscopic sleeve gastrectomy (LSG) increases transplant eligibility by reducing BMI in kidney transplant candidates, but the effect of surgical weight loss on posttransplantation outcomes is unknown. Reviewing single-center medical records, we identified all patients who underwent LSG before kidney transplantation from 2011-2016 (n = 20). Post-LSG kidney recipients were compared with similar-BMI recipients who did not undergo LSG, using 2:1 direct matching for patient factors. McNemar's test and signed-rank test were used to compare groups. Among post-LSG patients, mean BMI ± standard deviation (SD) was 41.5 ± 4.4 kg/m2 at initial encounter, which decreased to 32.3 ± 2.9 kg/m2 prior to transplantation (P < .01). No complications, readmissions, or mortality occurred following LSG. After transplantation, one patient (5%) experienced DGF, and no patients experienced NODAT. Allograft and patient survival at 1-year posttransplantation was 100%. Compared with non-LSG patients, post-LSG recipients had lower rates of DGF (5% vs 20%) and renal dysfunction-related readmissions (10% vs 27.5%) (P < .05 each). Perioperative complications, allograft survival, and patient survival were similar between groups. These data suggest that morbidly obese patients with end-stage renal disease who undergo LSG to improve transplant candidacy, achieve excellent posttransplantation outcomes.

Plasma thrombospondin 1 as a predictor of postoperative liver dysfunction.

BACKGROUND: Liver regeneration following liver resection involves a complex interplay of growth factors and their antagonists. Thrombospondin 1 has recently been identified as a critical inhibitor of liver regeneration by the activation of transforming growth factor ß1 in mice, and preliminary data seem to confirm its relevance in humans. This study aimed to confirm these observations in an independent validation cohort. METHODS: Perioperative circulating levels of thrombospondin 1 were measured in patients undergoing liver resection between January 2012 and September 2013. Postoperative liver dysfunction was defined according to the International Study Group of Liver Surgery and classification of morbidity was based on the criteria by Dindo et al. RESULTS: In 85 patients (44 major and 41 minor liver resections), plasma levels of thrombospondin 1 increased 1 day after liver resection (mean 51·6 ng/ml before surgery and 68·3 ng/ml on postoperative day 1; P = 0·001). Circulating thrombospondin 1 concentration on the first postoperative day specifically predicted liver dysfunction (area under the receiver operating characteristic (ROC) curve 0·818, P = 0·003) and was confirmed as a significant predictor in multivariable analysis (Exp(B) 1·020, 95 per cent c.i. 1·005 to 1·035; P = 0·009). Patients with a high thrombospondin 1 concentration (over 80 ng/ml) on postoperative day 1 more frequently had postoperative liver dysfunction than those with a lower level (28 versus 2 per cent) and severe morbidity (44 versus 15 per cent), and their length of hospital stay was more than doubled (19·7 versus 9·9 days). CONCLUSION: Thrombospondin 1 may prove a helpful clinical marker to predict postoperative liver dysfunction as early as postoperative day 1.

Orlistat-induced fulminant hepatic failure.

Orlistat was approved by the Food and Drug Administration in 1998 and has been shown to be superior to placebo in achieving weight loss. It is generally well tolerated. However, severe liver injury has been reported. We present a case of hepatic failure in a patient taking orlistat. A 54-year-old African-American woman with hypertension presented with hepatic failure. She had noticed increasing fatigue, jaundice and confusion. She used alcohol sparingly and denied tobacco or illicit drug use, but had been taking over-the-counter orlistat for the past two months. Physical examination revealed scleral icterus, jaundice, asterixis and slow speech. Laboratory testing showed markedly abnormal liver function tests with coagulopathy. Acute viral and autoimmune serologies were negative, as was toxicology screen. Liver biopsy showed necrotic hepatic parenchyma likely secondary to drug toxicity. Based upon her clinical presentation and time course, the pattern of liver injury seen on liver biopsy and lack of an alternative plausible explanation, her liver failure was most likely associated with orlistat use. She continued to deteriorate and ultimately underwent orthotopic liver transplantation. Fourteen cases of severe liver injury associated with orlistat use have been reported, four of which are detailed in the literature. This is the second published case of liver failure associated with over-the-counter orlistat usage. Clinicians should be aware of the growing number of cases associating liver injury and orlistat use and carefully monitor their patients on this medication for signs of hepatic dysfunction.

Neoadjuvant bevacizumab persistently inactivates VEGF at the time of surgery despite preoperative cessation.

BACKGROUND: When anti-VEGF (vascular endothelial growth factor) antibody bevacizumab is applied in neoadjuvant treatment of colorectal cancer patients with liver metastasis, 5-6 weeks between last bevacizumab dose and liver resection are currently recommended to avoid complications in wound and liver regeneration. In this context, we aimed to determine whether VEGF is inactivated by bevacizumab at the time of surgery. METHODS: Fifty colorectal cancer patients with liver metastases received neoadjuvant chemotherapy ± bevacizumab supplementation. The last dose of bevacizumab was administered 6 weeks before surgery. Plasma, subcutaneous and intraabdominal wound fluid were analysed for VEGF content before and after liver resection (day 1-3). Immunoprecipitation was applied to determine the amount of bevacizumab-bound VEGF. RESULTS: Bevacizumab-treated individuals showed no increase in perioperative complications. During the entire monitoring period, plasma VEGF was inactivated by bevacizumab. In wound fluid, VEGF was also completely bound by bevacizumab and was remarkably low compared with the control chemotherapy group. CONCLUSION: These data document that following a cessation time of 6 weeks, bevacizumab is fully active and blocks circulating and local VEGF at the time of liver resection. However, despite effective VEGF inactivation no increase in perioperative morbidity is recorded suggesting that VEGF activity is not essential in the immediate postoperative recovery period.

Awareness about clostridium difficile infection among internal medicine residents in the United States.

AIM: Clostridium difficile infection (CDI) is the leading infective cause of antibiotic associated diarrhea. The principal objective of this study was to assess the knowledge and awareness of internal medicine (IM) residents regarding the epidemiology, clinical recognition, diagnosis and management of CDI. METHODS: A 20-question survey was distributed to 90 IM residents in all three years of their post graduate training in a university-based program. The survey instrument assessed the resident's knowledge of the current epidemiological trend, clinical recognition and presentation, diagnosis and management of CDI. RESULTS: Forty two out of 90 (48%) residents completed the questionnaire. Only 10/42 (23.8%) of the residents recommended the gold standard investigation for diagnosing CDI. The majority of residents 29/42 (69%) were not aware of the existence of CDI in the outpatient setting and would not test for CDI. Only 50% of the residents were aware of the worse outcome of CDI in inflammatory bowel disease patients and only 12/42 (28.6%) would appropriately risk stratify and treat patients. Almost all of the residents (97.6%) knew about the appropriate time to consult surgery. There was no significant difference in the awareness with respect to the year of training (interns vs. residents), their career choices (primary care vs. fellowship) nor did the knowledge correlate with the United States medical licensing examination (USMLE) scores. CONCLUSION: IM residents had suboptimal knowledge of many aspects of the common problem of CDI. Educational efforts should be directed at IM residents, many of whom plan careers as primary care/hospitalists, who will encounter patients with CDI.

Gut microbes define liver cancer risk in mice exposed to chemical and viral transgenic hepatocarcinogens.

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) frequently results from synergism between chemical and infectious liver carcinogens. Worldwide, the highest incidence of HCC is in regions endemic for the foodborne contaminant aflatoxin B1 (AFB1) and hepatitis B virus (HBV) infection. Recently, gut microbes have been implicated in multisystemic diseases including obesity and diabetes. Here, the hypothesis that specific intestinal bacteria promote liver cancer was tested in chemical and viral transgenic mouse models. METHODS: Helicobacter-free C3H/HeN mice were inoculated with AFB1 and/or Helicobacter hepaticus. The incidence, multiplicity and surface area of liver tumours were quantitated at 40 weeks. Molecular pathways involved in tumourigenesis were analysed by microarray, quantitative real-time PCR, liquid chromatography/mass spectrometry, ELISA, western blot and immunohistochemistry. In a separate experiment, C57BL/6 FL-N/35 mice harbouring a full-length hepatitis C virus (HCV) transgene were crossed with C3H/HeN mice and cancer rates compared between offspring with and without H hepaticus. RESULTS: Intestinal colonisation by H hepaticus was sufficient to promote aflatoxin- and HCV transgene-induced HCC. Neither bacterial translocation to the liver nor induction of hepatitis was necessary. From its preferred niche in the intestinal mucus layer, H hepaticus activated nuclear factor-kappaB (NF-kappaB)-regulated networks associated with innate and T helper 1 (Th1)-type adaptive immunity both in the lower bowel and liver. Biomarkers indicative of tumour progression included hepatocyte turnover, Wnt/beta-catenin activation and oxidative injury with decreased phagocytic clearance of damaged cells. CONCLUSIONS: Enteric microbiota define HCC risk in mice exposed to carcinogenic chemicals or hepatitis virus transgenes. These results have implications for human liver cancer risk assessment and prevention.

Nitric oxide and TNF-alpha trigger colonic inflammation and carcinogenesis in Helicobacter hepaticus-infected, Rag2-deficient mice.

Recombinase-activating gene-2-deficient (Rag2(-/-)) mice lacking functional lymphocytes provide a useful model of chronic inflammatory bowel disease-emulating events in human colon cancer. Infection of Rag2(-/-) mice with Helicobacter hepaticus led to accumulation of macrophages and neutrophils in the colon, a process temporally related to up-regulation of tissue inducible nitric oxide synthase (iNOS) expression at the site of infection and increased nitric oxide (NO) production, as evidenced by urinary excretion of nitrate. Progressive development of increasingly severe inflammation, hyperplasia, dysplasia, and cancer accompanied these changes. Concurrent administration of an iNOS inhibitor prevented NO production and abrogated epithelial pathology and inhibited the onset of cancer. The presence of Gr-1(+) neutrophils and elevated tumor necrosis factor-alpha (TNF-alpha) expression in colon were required for increased iNOS expression and cancer, whereas interleukin-10 (IL-10) down-regulated TNF-alpha and iNOS expression and suppressed cancer. Anti-inflammatory CD4(+) regulatory lymphocytes also down-regulated iNOS and reduced cancer formation. Collectively, these results confirm essential roles for inflammation, increased TNF-alpha expression, and elevated NO production in colon carcinogenesis.

Q-band EPR biodosimetry in tooth enamel microsamples: feasibility test and comparison with x-band.

A comparative study of electron paramagnetic resonance dosimetry in Q- and X-bands has shown that Q-band is able to provide accurate measurements of radiation doses even below 0.5 Gy with tooth enamel samples as small as 2 mg. The optimal amount of tooth enamel for dose measurements in Q-band was found to be 4 mg. This is less than 1% of the total amount of tooth enamel in one molar tooth. Such a small amount of tooth enamel can be harmlessly obtained in an emergency requiring after-the-fact radiation dose measurement. The other important advantage of Q-band is full resolution of the radiation-induced EPR signal from the native, background signal. This separation makes dose response measurements much easier in comparison to conventional X-band measurements in which these overlapping signals necessitate special methods for doses below 0.5 Gy. The main disadvantages of Q-band measurements are a higher level of noise and lower spectral reproducibility than in X-band. The effect of these negative factors on the precision of dose measurements in Q-band could probably be reduced by improvement of sample fixation in the resonance cavity and better optimization of signal filtration to reduce high-frequency noise.

Retrospective assessment of radiation exposure using biological dosimetry: chromosome painting, electron paramagnetic resonance and the glycophorin a mutation assay.

Biological monitoring of dose can contribute important, independent estimates of cumulative radiation exposure in epidemiological studies, especially in studies in which the physical dosimetry is lacking. Three biodosimeters that have been used in epidemiological studies to estimate past radiation exposure from external sources will be highlighted: chromosome painting or FISH (fluorescence in situ hybridization), the glycophorin A somatic mutation assay (GPA), and electron paramagnetic resonance (EPR) with teeth. All three biodosimeters have been applied to A-bomb survivors, Chernobyl clean-up workers, and radiation workers. Each biodosimeter has unique advantages and limitations depending upon the level and type of radiation exposure. Chromosome painting has been the most widely applied biodosimeter in epidemiological studies of past radiation exposure, and results of these studies provide evidence that dose-related translocations persist for decades. EPR tooth dosimetry has been used to validate dose models of acute and chronic radiation exposure, although the present requirement of extracted teeth has been a disadvantage. GPA has been correlated with physically based radiation dose after high-dose, acute exposures but not after low-dose, chronic exposures. Interindividual variability appears to be a limitation for both chromosome painting and GPA. Both of these techniques can be used to estimate the level of past radiation exposure to a population, whereas EPR can provide individual dose estimates of past exposure. This paper will review each of these three biodosimeters and compare their application in selected epidemiological studies.

The Third International Intercomparison on EPR Tooth Dosimetry: part 2, final analysis.

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation.

Parameters affecting EPR dose reconstruction in teeth.

The aim of this paper is to analyze the lower limit of detection (LLD), linearity of dose response, variation of radiation sensitivity between different tooth enamel samples, and time/temperature stability of EPR biodosimetry in tooth enamel. The theoretical LLD is shown to be 0.46 mGy, which is far lower than the measured value of about 30 mGy. The main issues to lowering LLD are the differentiation of the radiation-induced component against the total EPR spectrum and the complex nature of the dose dependence of the EPR signal. The following questions are also discussed in detail: need for exfoliated or extracted teeth from persons of interest, accounting for background radiation contribution; conversion of tooth enamel absorbed dose to effective dose; accounting for internal exposure specifically from bone-seeking radionuclides. Conclusions on future development of EPR retrospective biodosimetry are made.

The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis.

The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose.

Spectrum file size optimization for EPR tooth dosimetry.

Spectral acquisition time is one of the limiting factors in electron paramagnetic resonance (EPR) retrospective biodosimetry in teeth. Acquisition times for one sample can be from 2 to 4h. This problem is even more acute for in vivo EPR measurements in L-band. Patients cannot be expected to remain stationary for these lengths of time. In order to overcome this limitation, we investigated the dependence of EPR dose measurements on the number of data points in an EPR spectrum. We have shown that this number could be reduced from 1024 to 256 (factor of 4 reduction in spectral acquisition time) at 5 mT magnetic field sweep without a loss of precision in the dose measurements.

Electrofusion of a weakly immunogenic neuroblastoma with dendritic cells produces a tumor vaccine.

The absence of surface costimulatory molecules explains in part the lack of an effective anti-tumor immune response in tumor-bearing animals, even though unique tumor antigens may be presented by class I MHC. We determined that the immunogenicity of a murine neuroblastoma, Neuro-2a, which lacks surface costimulatory molecules, could be increased by electrically induced fusion with dendritic cells. Electrofusion induced a higher level of cell fusion than polyethylene glycol, and tumor/dendritic cell heterokaryons expressed high levels of costimulatory molecules. While Neuro-2a was unable to induce the proliferation of syngeneic or allogeneic T cells in vitro, fused cells were able to induce T cell responses both in vitro and in vivo. When fused dendritic tumor cells were used as a cancer vaccine, immunized mice were significantly protected from challenge with Neuro-2a. We propose that electrofusion with patient-derived tumor and dendritic cells may provide a rapid means to produce patient-specific tumor vaccines.

Genomic characterization of Helicobacter hepaticus: ordered cosmid library and comparative sequence analysis.

Helicobacter hepaticus is an important pathogen in laboratory mice and induces the development of liver tumors and gastrointestinal disease in susceptible strains of mice. In this study, a miniset of 36 cosmid clones from a genomic library of H. hepaticus was ordered and grouped into four large contigs representing approximately 1 Mb of the H. hepaticus genome using PCR, DNA sequencing, Southern and dot-blot hybridization and pulsed-field gel electrophoresis. From the 200-300 terminal nucleotide sequences of 38 cosmid clones, 56 coding regions were predicted, of which 51 were found to have orthologs in the public databases and five appeared to be unique to H. hepaticus. Of these 51 genes, 36 have orthologs in Helicobacter pylori and 25 display the highest sequence similarity to H. pylori. However, chromosomal positions of these genes are not conserved between these two helicobacters. In addition, 10 H. hepaticus genes had the highest sequence similarity to orthologs in Campylobacter jejuni. The GC content in a randomly selected 21-kb H. hepaticus genomic sequence was 35.8%, which approximates the average between H. pylori (39%) and C. jejuni (30.6%). These results demonstrate that: (1) H. hepaticus is more closely related to H. pylori than C. jejuni; (2) significant genomic alterations exist between H. hepaticus and H. pylori, including gene organization, protein sequences and GC content, probably in part due to specific adaptation to distinct ecological niches.

Enteropathogenic Escherichia coli and ulcerative colitis in cotton-top tamarins (Saguinus oedipus).

The cotton-top tamarin (CTT; Saguinus oedipus) is an endangered New World primate that develops a highly prevalent idiopathic colitis resembling human ulcerative colitis. This study found that enteropathogenic Escherichia coli (EPEC) caused acute colitis in CTTs, which was associated with ulcerative colitis. EPEC clinical isolates revealed localized adherence patterns by HEp-2 assay and were devoid of Shiga-toxin production. Sequencing of the eae gene (GenBank accession no. AF319597) revealed 99.2% identity to sequences of human isolates (GenBank AF116899) and corresponded to the epsilon intimin gene subtype. Detection of intimin sequences by polymerase chain reaction on primary fecal cultures indicated widespread EPEC infection in the CTT colony. Prospective analysis revealed that animals with fecal cultures positive for intimin sequences had a higher frequency of active colitis (75.0% vs. 27.2%; P<.005, chi(2) test) and higher histological scores of colonic inflammation (0.875 vs. 0.455, respectively; P<.05, Mann-Whitney rank sum test).

Bacterial infection promotes colon tumorigenesis in Apc(Min/+) mice.

The Min mouse, which has a germ line mutation in 1 allele of the Apc tumor suppressor gene, is a model for the early steps in human colorectal cancer. Helicobacter pylori infection, a known risk factor for gastric cancer in humans, causes chronic inflammation and increased epithelial cell proliferation in the stomach. Infection with the bacterium Citrobacter rodentium is known to increase epithelial cell proliferation and to promote chemically initiated tumors in the colon of mice. Min mice infected with C. rodentium at 1 month of age were found to have a 4-fold increase in the number of colonic adenomas at 6 months of age, compared with uninfected Min mice. Most of the colonic adenomas in the infected Min mice were in the distal colon, where C. rodentium-induced hyperplasia occurs. These data demonstrate that bacterial infection promotes colon tumor formation in genetically susceptible mice.

Molecular pathogenesis of Citrobacter rodentium and transmissible murine colonic hyperplasia.

Here we review the history, clinical significance, pathology and molecular pathogenesis of Citrobacter rodentium, the causative agent of transmissible murine colonic hyperplasia. C. rodentium serves as an important model pathogen for investigating the mechanisms controlling attaching and effacing pathology, epithelial hyperproliferation, and tumor promotion in the distal colon of the mouse.