Gut Microbiota to Microglia: Microbiome Influences Neurodevelopment in the CNS

The brain is traditionally viewed as an immunologically privileged site; however, there are known to be multiple resident immune cells that influence the CNS environment and are reactive to extra-CNS signaling. Microglia are an important component of this system, which influences early neurodevelopment in addition to modulating inflammation and regenerative responses to injury and infection. Microglia are influenced by gut microbiome-derived metabolites, both as part of their normal function and potentially in pathological patterns that may induce neurodevelopmental disabilities or behavioral changes. This review aims to summarize the mounting evidence indicating that, not only is the Gut-Brain axis mediated by metabolites and microglia throughout an organism's lifetime, but it is also influenced prenatally by maternal microbiome and diet, which holds implications for both early neuropathology and neurodevelopment.

Gut Microbiota Modulation of Short Bowel Syndrome and the Gut-Brain Axis

Short bowel syndrome (SBS) is a condition that results from a reduction in the length of the intestine or its functional capacity. SBS patients can have significant side effects and complications, the etiology of which remains ill-defined. Thus, facilitating intestinal adaptation in SBS remains a major research focus. Emerging data supports the role of the gut microbiome in modulating disease progression. There has been ongoing debate on defining a "healthy" gut microbiome, which has led to many studies analyzing the bacterial composition and shifts that occur in gastrointestinal disease states such as SBS and the resulting systemic effects. In SBS, it has also been found that microbial shifts are highly variable and dependent on many factors, including the anatomical location of bowel resection, length, and structure of the remnant bowel, as well as associated small intestinal bacterial overgrowth (SIBO). Recent data also notes a bidirectional communication that occurs between enteric and central nervous systems called the gut-brain axis (GBA), which is regulated by the gut microbes. Ultimately, the role of the microbiome in disease states such as SBS have many clinical implications and warrant further investigation. The focus of this review is to characterize the role of the gut microbiota in short bowel syndrome and its impact on the GBA, as well as the therapeutic potential of altering the microbiome.

Ethanol and isopropanol inactivation of human coronavirus on hard surfaces

BACKGROUND

The coronavirus disease 2019 pandemic has greatly increased the frequency of disinfecting surfaces in public places, causing a strain on the ability to obtain disinfectant solutions. An alternative is to use plain alcohols (EtOH and IPA) or sodium hypochlorite (SH).

AIM

To determine the efficacy of various concentrations of EtOH, IPA and SH on a human coronavirus (HCoV) dried on to surfaces using short contact times.

METHODS

High concentrations of infectious HCoV were dried on to porcelain and ceramic tiles, then treated with various concentrations of the alcohols for contact times of 15 s, 30 s and 1 min. Three concentrations of SH were also tested. Reductions in titres were measured using the tissue culture infectious dose 50 assay.

FINDINGS

Concentrations of EtOH and IPA from 62% to 80% were very efficient at inactivating high concentrations of HCoV dried on to tile surfaces, even with a 15-s contact time. Concentrations of 95% dehydrated the virus, allowing infectious virus to survive. The dilutions of SH recommended by the Centers for Disease Control and Prevention (1/10 and 1/50) were efficient at inactivating high concentrations of HCoV dried on to tile surfaces, whereas a 1/100 dilution had substantially lower activity.

CONCLUSIONS

Multiple concentrations of EtOH, IPA and SH efficiently inactivated infectious HCoV on hard surfaces, typical of those found in public places. Often no remaining infectious HCoV could be detected.

Interleukin 6-dependent genomic instability heralds accelerated carcinogenesis following liver regeneration on a background of chronic hepatitis

Liver cancer, which typically develops on a background of chronic liver inflammation, is now the second leading cause of cancer mortality worldwide. For patients with liver cancer, surgical resection is a principal treatment modality that offers a chance of prolonged survival. However, tumor recurrence after resection, the mechanisms of which remain obscure, markedly limits the long-term survival of these patients. We have shown that partial hepatectomy in multidrug resistance 2 knockout (Mdr2^-/- ) mice, a model of chronic inflammation-associated liver cancer, significantly accelerates hepatocarcinogenesis. Here, we explore the postsurgical mechanisms that drive accelerated hepatocarcinogenesis in Mdr2^-/- mice by perioperative pharmacological inhibition of interleukin-6 (IL6), which is a crucial liver regeneration priming cytokine. We demonstrate that inhibition of IL6 signaling dramatically impedes tumorigenesis following partial hepatectomy without compromising survival or liver mass recovery. IL6 blockade significantly inhibited hepatocyte cell cycle progression while promoting a hypertrophic regenerative response, without increasing apoptosis. Mdr2^-/- mice contain hepatocytes with a notable persistent DNA damage response (γH2AX, 53BP1) due to chronic inflammation. We show that liver regeneration in this microenvironment leads to a striking increase in hepatocytes bearing micronuclei, a marker of genomic instability, which is suppressed by IL6 blockade.

CONCLUSION

Our findings indicate that genomic instability derived during the IL6-mediated liver regenerative response within a milieu of chronic inflammation links partial hepatectomy to accelerated hepatocarcinogenesis; this suggests a new therapeutic approach through the usage of an anti-IL6 treatment to extend the tumor-free survival of patients undergoing surgical resection. (Hepatology 2017;65:1600-1611).

Chronic liver inflammation modifies DNA methylation at the precancerous stage of murine hepatocarcinogenesis

Chronic liver inflammation precedes the majority of hepatocellular carcinomas (HCC). Here, we explore the connection between chronic inflammation and DNA methylation in the liver at the late precancerous stages of HCC development in Mdr2(-/-) (Mdr2/Abcb4-knockout) mice, a model of inflammation-mediated HCC. Using methylated DNA immunoprecipitation followed by hybridization with "CpG islands" (CGIs) microarrays, we found specific CGIs in 76 genes which were hypermethylated in the Mdr2(-/-) liver compared to age-matched healthy controls. The observed hypermethylation resulted mainly from an age-dependent decrease of methylation of the specific CGIs in control livers with no decrease in mutant mice. Chronic inflammation did not change global levels of DNA methylation in Mdr2(-/-) liver, but caused a 2-fold decrease of the global 5-hydroxymethylcytosine level in mutants compared to controls. Liver cell fractionation revealed, that the relative hypermethylation of specific CGIs in Mdr2(-/-) livers affected either hepatocyte, or non-hepatocyte, or both fractions without a correlation between changes of gene methylation and expression. Our findings demonstrate that chronic liver inflammation causes hypermethylation of specific CGIs, which may affect both hepatocytes and non-hepatocyte liver cells. These changes may serve as useful markers of an increased regenerative activity and of a late precancerous stage in the chronically inflamed liver.

Specific genomic and transcriptomic aberrations in tumors induced by partial hepatectomy of a chronically inflamed murine liver

Resection of hepatocellular carcinoma (HCC) tumors by partial hepatectomy (PHx) is associated with promoting hepatocarcinogenesis. We have previously reported that PHx promotes hepatocarcinogenesis in the Mdr2-knockout (Mdr2-KO) mouse, a model for inflammation-mediated HCC. Now, to explore the molecular mechanisms underlying the tumor-promoting effect of PHx, we compared genomic and transcriptomic profiles of HCC tumors developing in the Mdr2-KO mice either spontaneously or following PHx. PHx accelerated HCC development in these mice by four months. PHx-induced tumors had major chromosomal aberrations: all were amplifications affecting multiple chromosomes. Most of these amplifications were located near the acrocentric centromeres of murine chromosomes. Four different chromosomal regions were amplified each in at least three tumors. The human orthologs of these common amplified regions are known to be amplified in HCC. All tumors of untreated mice had chromosomal aberrations, including both deletions and amplifications. Amplifications in spontaneous tumors affected fewer chromosomes and were not located preferentially at the chromosomal edges. Comparison of gene expression profiles revealed a significantly enriched expression of oncogenes, chromosomal instability markers and E2F1 targets in the post-PHx compared to spontaneous tumors. Both tumor groups shared the same frequent amplification at chromosome 18. Here, we revealed that one of the regulatory genes encoded by this amplified region, Crem, was over-expressed in the nuclei of murine and human HCC cells in vivo, and that it stimulated proliferation of human HCC cells in vitro. Our results demonstrate that PHx of a chronically inflamed liver directed tumor development to a discrete pathway characterized by amplification of specific chromosomal regions and expression of specific tumor-promoting genes. Crem is a new candidate HCC oncogene frequently amplified in this model and frequently over-expressed in human HCC.

Inflammation-induced hepatocellular carcinoma is dependent on CCR5 in mice

Human hepatocellular carcinoma (HCC) is an inflammation-induced cancer, which is the third-leading cause of cancer mortality worldwide. We investigated the role of the chemokine receptors, CCR5 and CCR1, in regulating inflammation and tumorigenesis in an inflammation-induced HCC model in mice. Multidrug resistance 2 gene (Mdr2)-knockout (Mdr2-KO) mice spontaneously develop chronic cholestatic hepatitis and fibrosis that is eventually followed by HCC. We generated two new strains from the Mdr2-KO mouse, the Mdr2:CCR5 and the Mdr2:CCR1 double knockouts (DKOs), and set out to compare inflammation and tumorigenesis among these strains. We found that in Mdr2-KO mice lacking the chemokine receptor, CCR5 (Mdr2:CCR5 DKO mice), but not CCR1 (Mdr2:CCR1 DKO), macrophage recruitment and trafficking to the liver was significantly reduced. Furthermore, in the absence of CCR5, reduced inflammation was also associated with reduced periductal accumulation of CD24(+) oval cells and abrogation of fibrosis. DKO mice for Mdr2 and CCR5 exhibited a significant decrease in tumor incidence and size.

CONCLUSIONS

Our results indicate that CCR5 has a critical role in both the development and progression of liver cancer. Therefore, we propose that a CCR5 antagonist can serve for HCC cancer prevention and treatment.

Transduction of fetal mice with a feline lentiviral vector induces liver tumors which exhibit an E2F activation signature

Lentiviral vectors are widely used in basic research and clinical applications for gene transfer and long-term expression; however, safety issues have not yet been completely resolved. In this study, we characterized hepatocarcinomas that developed in mice 1 year after in utero administration of a feline-derived lentiviral vector. Mapped viral integration sites differed among tumors and did not coincide with the regions of chromosomal aberrations. Furthermore, gene expression profiling revealed that no known cancer-associated genes were deregulated in the vicinity of viral integrations. Nevertheless, five of the six tumors exhibited highly significant upregulation of E2F target genes, of which a majority are associated with oncogenesis, DNA damage response, and chromosomal instability. We further show in vivo and in vitro that E2F activation occurs early on following transduction of both fetal mice and cultured human hepatocytes. On the basis of the similarities in E2F target gene expression patterns among tumors and the lack of evidence implicating insertional mutagenesis, we propose that transduction of fetal mice with a feline lentiviral vector induces E2F-mediated major cellular processes that drive hepatocytes toward uncontrolled proliferation culminating in tumorigenesis.

Interstrain differences in chronic hepatitis and tumor development in a murine model of inflammation-mediated hepatocarcinogenesis

Chronic inflammation is strongly associated with an increased risk for hepatocellular carcinoma (HCC) development. The multidrug resistance 2 (Mdr2)-knockout (KO) mouse (adenosine triphosphate-binding cassette b4(-/-) ), a model of inflammation-mediated HCC, develops chronic cholestatic hepatitis at an early age and HCC at an adult age. To delineate factors contributing to hepatocarcinogenesis, we compared the severity of early chronic hepatitis and late HCC development in two Mdr2-KO strains: Friend virus B-type/N (FVB) and C57 black 6 (B6). We demonstrated that hepatocarcinogenesis was significantly less efficient in the Mdr2-KO/B6 mice versus the Mdr2-KO/FVB mice; this difference was more prominent in males. Chronic hepatitis in the Mdr2-KO/B6 males was more severe at 1 month of age but was less severe at 3 months of age in comparison with age-matched Mdr2-KO/FVB males. A comparative genome-scale gene expression analysis of male livers of both strains at 3 months of age revealed both common and strain-specific aberrantly expressed genes, including genes associated with the regulation of inflammation, the response to oxidative stress, and lipid metabolism. One of these regulators, galectin-1 (Gal-1), possesses both anti-inflammatory and protumorigenic activities. To study its regulatory role in the liver, we transferred the Gal-1-KO mutation (lectin galactoside-binding soluble 1(-/-) ) from the B6 strain to the FVB strain, and we demonstrated that endogenous Gal-1 protected the liver against concanavalin A-induced hepatitis with the B6 genetic background but not the FVB genetic background.

CONCLUSION

Decreased chronic hepatitis in Mdr2-KO/B6 mice at the age of 3 months correlated with a significant retardation of liver tumor development in this strain versus the Mdr2-KO/FVB strain. We found candidate factors that may determine strain-specific differences in the course of chronic hepatitis and HCC development in the Mdr2-KO model, including inefficient anti-inflammatory activity of the endogenous lectin Gal-1 in the FVB strain.

Abstract B38: Epigenetic effects of viral proteins on global levels of 5-hydroxymethylcytosine in HBV- and HCV-associated hepatocellular carcinoma in mice

Hepatitis B virus (HBV) and hepatitis C virus (HCV) have both distinct and shared pathways to mediate development of virus-associated hepatocellular carcinoma (HCC). It has been postulated that viral encoded proteins such as HCV polyprotein or HBV X protein (HBx) induce epigenetic changes that can lead to HCC during chronic infection. 5-Hydroxymethylcytosine (5hmC) is a recently identified cytosine variant and an intermediate in enzyme-catalyzed active DNA demethylation. 5hmC is also considered a stable epigenetic mark during embryo development and tumorigenesis. Herein, we developed a liquid chromatography-mass spectrometry (LC-MS) based approach to assess global genomic 5hmC levels in tissues using several transgenic (Tg) mouse models to determine epigenetic changes induced by HBV and HCV viral proteins and role in pathogenesis of HCC.

A 2-to 3-fold reduction in genomic 5hmC was observed in liver samples from both Mdr2-knockout (Mdr2-KO) mice (a model of chronic inflammation-mediated HCC) and Mdr2-KO/HCV-Tg mice (a model carrying Mdr2-KO and HCV polyprotein). Interestingly, a similar fold reduction in 5hmC was detected in (Mdr2+/-)/HCV-Tg mice, which express HCV polyprotein, but do not develop HCC. In parallel, 5hmC levels were assessed in HBx-Tg mice with high-frequency of HCC. However, reduction of 5hmC was not detectable in liver samples from HBx-Tg mice as late as 14 months of age.

These results suggest that HCV polyprotein may accelerate inflammation-associated hepato-carcinogenesis in the Mdr2-KO/HCV-Tg mice. Therefore, we speculate that the HCV proteins may directly induce deconstruction of genomic 5hmC to promote HCC development. In contrast, our results in HBx-Tg mice suggest that HBx may employ a different epigenetic mechanism on 5hmC from that of HCV polyprotein. Notably, a significant change in genomic 5hmC was observed early at the pre-cancerous stages of HCC development in Mdr2-KO mice. This finding implies that, during chronic inflammation, a precipitous drop in 5hmC emerges prior to tumor formation. Therefore, 5hmC may provide an important diagnostic marker for early detection of HCC in persons with HCV chronic infection.

Citation Format: Yong Jiang, Ting Nie, James Kohler, Leda Bassit, Daniel Goldenberg, Mark Feitelson, Raymond F. Schinazi. Epigenetic effects of viral proteins on global levels of 5-hydroxymethylcytosine in HBV- and HCV-associated hepatocellular carcinoma in mice. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Jun 19-22, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2013;73(13 Suppl):Abstract nr B38.

Accelerated carcinogenesis following liver regeneration is associated with chronic inflammation-induced double-strand DNA breaks

Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality worldwide and is considered to be the outcome of chronic liver inflammation. Currently, the main treatment for HCC is surgical resection. However, survival rates are suboptimal partially because of tumor recurrence in the remaining liver. Our aim was to understand the molecular mechanisms linking liver regeneration under chronic inflammation to hepatic tumorigenesis. Mdr2-KO mice, a model of inflammation-associated cancer, underwent partial hepatectomy (PHx), which led to enhanced hepatocarcinogenesis. Moreover, liver regeneration in these mice was severely attenuated. We demonstrate the activation of the DNA damage-response machinery and increased genomic instability during early liver inflammatory stages resulting in hepatocyte apoptosis, cell-cycle arrest, and senescence and suggest their involvement in tumor growth acceleration subsequent to PHx. We propose that under the regenerative proliferative stress induced by liver resection, the genomic unstable hepatocytes generated during chronic inflammation escape senescence and apoptosis and reenter the cell cycle, triggering the enhanced tumorigenesis. Thus, we clarify the immediate and long-term contributions of the DNA damage response to HCC development and recurrence.

Incidence and risk factors of aplastic anemia in Latin American countries: the LATIN case-control study

Background Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained.

DESIGN AND METHODS

This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis.

RESULTS

The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure (>/=30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82-9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87-87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14-108.02). Conclusions The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone.

HCV tumor promoting effect is dependent on host genetic background

BACKGROUND

The hepatitis C virus (HCV) is one of the major risk factors for the development of hepatocellular carcinoma (HCC). Nevertheless, transgenic mice which express the whole HCV polyprotein (HCV-Tg) do not develop HCC. Whereas chronic HCV infection causes inflammation in patients, in HCV-Tg mice, the host immune reaction against viral proteins is lacking. We aimed to test the role of HCV proteins in HCC development on the background of chronic inflammation in vivo.

METHODOLOGY/PRINCIPAL FINDINGS

We crossed HCV-Tg mice that do not develop HCC with the Mdr2-knockout (Mdr2-KO) mice which develop inflammation-associated HCC, to generate Mdr2-KO/HCV-Tg mice. We studied the effect of the HCV transgene on tumor incidence, hepatocyte mitosis and apoptosis, and investigated the potential contributing factors for the generated phenotype by gene expression and protein analyses. The Mdr2-KO/HCV-Tg females from the N2 generation of this breeding (having 75% of the FVB/N genome and 25% of the C57BL/6 genome) produced significantly larger tumors in comparison with Mdr2-KO mice. In parallel, the Mdr2-KO/HCV-Tg females had an enhanced inflammatory gene expression signature. However, in the N7 generation (having 99.2% of the FVB/N genome and 0.8% of the C57BL/6 genome) there was no difference in tumor development between Mdr2-KO/HCV-Tg and Mdr2-KO animals of both sexes. The HCV transgene was similarly expressed in the livers of Mdr2-KO/HCV-Tg females of both generations, as revealed by detection of the HCV transcript and the core protein.

CONCLUSION

These findings suggest that the HCV transgene accelerated inflammation-associated hepatocarcinogenesis in a host genetic background-dependent manner.

Molecular mechanisms of liver carcinogenesis in the mdr2-knockout mice

Mouse models of hepatocellular carcinoma (HCC) simulate specific subgroups of human HCC. We investigated hepatocarcinogenesis in Mdr2-knockout (Mdr2-KO) mice, a model of inflammation-associated HCC, using gene expression profiling and immunohistochemical analyses. Gene expression profiling showed that although Mdr2-KO mice differ from other published murine HCC models, they share several important deregulated pathways and many coordinately differentially expressed genes with human HCC data sets. Analysis of genome positions of differentially expressed genes in liver tumors revealed a prolonged region of down-regulated genes on murine chromosome 8 in three of the six analyzed tumor samples. This region is syntenic to human chromosomal regions that are frequently deleted in human HCC and harbor multiple tumor suppressor genes. Real-time reverse transcription-PCR analysis of 16 tumor samples confirmed down-regulation of several tumor suppressors in most tumors. We show that in the aged Mdr2-KO mice, cyclin D1 nuclear level is increased in dysplastic hepatocytes that do not form nodules; however, it is decreased in most dysplastic nodules and in liver tumors. We found that this decrease is mostly at the protein, rather than the mRNA, level. These findings raise the question on the role of cyclin D1 at early stages of hepatocarcinogenesis in the Mdr2-KO HCC model. Furthermore, we show that most liver tumors in Mdr2-KO mice were characterized by the absence of beta-catenin activation. In conclusion, the Mdr2-KO mouse may serve as a model for beta-catenin-negative subgroup of human HCCs characterized by low nuclear cyclin D1 levels in tumor cells and by down-regulation of multiple tumor suppressor genes.

Testing transgenic regulatory elements through live mouse imaging

To overcome positional and methylation effects on transgene expression, we developed a universal cloning cassette for in vivo assessment of regulatory elements using the luciferase reporter gene and the CCCD camera. Monitoring luciferase expression pattern in live mice enables screening of large numbers of transgenic founders quickly and inexpensively. We demonstrate that in the engineered transgenic mice, the chicken beta-globin 5'HS4 insulator did not always provide the desirable expression pattern, and the Island Element, responsible for the demethylation of the surrounding DNA region, was not beneficial. Both tested liver-specific and developmentally regulated promoters exhibited the expected expression pattern in most transgenic founders.

A novel bispecific antibody (bsMAb) construct for nuclear imaging of pancreatic cancer

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Background: The initial diagnosis of pancreatic cancer is difficult at best. We developed MAb-PAM4 reactive with a unique epitope within MUC1 that is expressed in most pancreatic cancers, but not in normal or inflammatory pancreas, nor most other normal and neoplastic tissues. Our current focus is the development of a pretargeting procedure that can greatly enhance targeting sensitivity while retaining the MAb’s high specificity. Methods: TF10 is a novel humanized recombinant bsMAb with divalent binding to PAM4-defined MUC1 and monovalent binding to histamine-succinyl-glycine (HSG). TF10 is a 157 kDa protein having >85% binding to MUC1 and >90% with HSG. Athymic nude mice bearing CaPan1, human pancreatic cancer, were injected with 125I-TF10 to assess biodistribution. Other animals were given varying doses of TF10 followed 16 h later with 111In-IMP-288, a divalent-HSG-peptide. These animals were imaged 3 h after the 111In-IMP-288-injection and then necropsied. Results: 125I-labeled TF10 cleared rapidly from the blood, with blood levels <0.25 ± 0.02 %ID/g at 16 h, and no accumulation in any normal tissues. Tumor uptake was 7.16 ± 1.10, 3.47 ± 0.66, and 1.65 ± 0.57 % ID/g at 6, 16, and 48 hrs, respectively. These data confirmed that for a pretargeted imaging study a 16-h interval is sufficient to clear the blood so that 111In-IMP-288 could be administered. At 3 h, the imaging studies showed intense uptake of radiolabeled peptide within the tumors (avg. 0.5 cm3 - 0.3 g at necropsy) with no evidence of uptake in any normal tissues, while no targeting was seen in animals given the 111In-IMP-288 alone. At necropsy, tumor uptake of the 111In-IMP-288 in the TF10 pretargeted animals was 24.3 ± 1.7 % ID/g, while for 111In-IMP-288 alone tumor uptake was only 0.012 ± 0.002 % ID/g. Tumor/blood, liver, lungs, and kidney ratios averaged 2800:1, 139:1, 184:1, and 14.2:1, respectively, in the pretargeted animals. Conclusions: These results demonstrate that this novel PAM4-based pretargeting agent targets and images xenografted human pancreatic cancer with high signal-to-background ratios. In addition to imaging, TF10 may prove useful for pretargeted therapy of pancreas cancer. (Supported in part by grant CA115755 from the NIH.)

No significant financial relationships to disclose.

Molecular mechanisms of the chemopreventive effect on hepatocellular carcinoma development in Mdr2 knockout mice

Dietary antioxidants and selenium compounds were shown to have a therapeutic effect against hepatocellular carcinoma in several mouse models. We tested the effects of tannic acid and selenomethionine on hepatocellular carcinoma development in Mdr2 knockout (Mdr2-KO) mice. Mdr2-KO and age-matched Mdr2 heterozygous control mice were fed with tannic acid or selenomethionine during the first 3 months of life. Then, several mice from each group were sacrificed, and liver tissue samples were removed for analysis. The remaining mice were fed a regular diet until the age of 16 months, at which time the number and size of liver tumors were determined. Liver tissue samples of 3-month-old mice were subjected to gene expression profiling analysis using cDNA macroarrays containing probes for 240 genes that regulate responses to oxidative stress and inflammation or lipid metabolism. Both tannic acid and selenomethionine had partial chemopreventive effect on development of hepatocellular carcinoma in Mdr2-KO mice: they reduced the incidence of large tumor nodules (diameter >1 cm) at age 16 months. Both agents inhibited gene expression and reversed up-regulation of many genes that control inflammation or response to oxidative stress in Mdr2-KO livers at age 3 months. This inhibitory effect on gene expression correlated with the ability of agents to reduce incidence of large tumors: selenomethionine was more active than tannic acid in both aspects. Understanding the molecular mechanism of chemoprevention effect could improve our therapeutic modalities while using these agents.

TGFbeta-dependent gene expression profile during maturation of dendritic cells

Primary immune response to pathogens involves the maturation of antigen-presenting dendritic cells (DC). Bacterial lipopolysacharride (LPS) is a potent inducer of DC maturation, whereas the transforming growth factor beta (TGFbeta) attenuates much of this process. Here, we analyzed the global gene expression pattern in LPS-treated bone marrow derived DC during inhibition of their maturation process by TGFbeta. Exposure of DC to LPS induces a pronounced cell response, manifested in altered expression of a large number of genes. Interestingly, TGFbeta did not affect most of the LPS responding genes. Nevertheless, analysis identified a subset of genes that did respond to TGFbeta, among them the two inflammatory cytokines interleukin (IL)-12 and IL-18. Expression of IL-12, the major proinflammatory cytokine secreted by mature DC, was downregulated by TGFbeta, whereas the expression level of the proinflammatory cytokine IL-18, known to potentiate the IL-12 effect, was upregulated. Expression of the peroxisome proliferator-activated receptor gamma (PPARgamma) increased in response to TGFbeta, concomitantly with reduced expression of chemokine receptor 7 (CCR7). This finding supports the possibility that TGFbeta-dependent inhibition of CCR7 expression in DC is mediated by PPARgamma.

Phase II trial of repeated carcinoembryonic antigen (CEA) radioimmunotherapy (RAIT) with 131I-Labetuzumab post salvage resection of colorectal metastases in the liver

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Background: Complete resection of liver metastases (LM) remains the treatment of choice for colorectal cancer (CRC). As shown recently (Liersch et al., JCO 2005; 23:6763–70), RAIT with a single application of the humanized monoclonal anti-CEA antibody, 131I-labetuzumab, improved both the median overall survival (OS) and 5-yr survival rates significantly in patients post salvage resection of LM. The major adverse side effects (≤ grade 3 CTC) were transient myelosuppression and/or thrombocytopenia in patients receiving 40 to 60 mCi/m2 of 131I-labetuzumab. These encouraging results stimulated the current ongoing Phase-II trial to evaluate the safety of repeated RAIT at doses of 2 × 50 mCi/m2 (3 mos apart), post salvage resection of LM. Methods: At present, 13 patients (primary CRC: 8x UICC stage IV, 1× UICC stage III and 4× UICC stage II) who underwent surgery for LM of CRC (postsalvage mTMN stages: 4× mT4, 2× mT3, 6× mT2, 1× mT1) have received the first dose of 50 mCi/m2 131I-labetuzumab within 2 mos of LM surgery. Three months later, a second infusion of 50 mCi/m2 has already been given to 5 pts. In two, a dose reduction to 40 mCi/m2 was performed. At re-staging CT and PET scans) for the 2nd RAIT, in one patient pulmonary metastases were diagnosed and in another patient a re-resection of hepatic relapse was performed. Results: In the previous trial, at a median follow-up of 67 mos, the median OS from the first liver resection for 19 pts treated with single-dose RAIT was 68.0 mos and median DFS was 18.0 mos. Also, 5-year survival was achieved by 51.3% of RAIT pts independently of bilobar involvement, size and number of LM, or resection margins. In the current study with repeated RAIT, transient grade-4 myelosuppression (2 cases in combination with a myelotoxic thiamazol medication) occurred in 4/13 pts after the first dose (1× grade 4 thrombocytopenia). No cumulative toxicity was seen in 6 of 7 RAIT-re-treated patients. Complete bone marrow recovery was observed in all 6 cases within 5–12 weeks; in one pt severe neutropenia persisted to about week 16 post 2nd RAIT. As of January, 2006, patient compliance was 100%. Conclusion: RAIT re-treatment to-date appears to be safe, feasible, and well accepted. Extended follow-up data are being collected.

[Table: see text]

Lentiviral vectors harboring a dual-gene system allow high and homogeneous transgene expression in selected polyclonal human embryonic stem cells

Genetic modification of human embryonic stem cells (hESCs) is highly valuable for their exploitation in basic science and therapeutic applications. Here we developed lentiviral vectors (LVs) constitutively expressing a reporter and a selectable marker to enable high and homogeneous transgene expression within polyclonal hESCs. LVs carrying GFP and a downstream puromycin resistance gene, linked by the encephalomyocarditis virus (EMCV) or poliovirus internal ribosome entry sites (IRES), allowed homogeneous GFP expression after antibiotic selection. The GFP-expression levels were higher with the EMCV IRES. We also developed dual-promoter vectors harboring a reporter and an antibiotic resistance gene under the regulation of human EF1alpha and PGK1 promoters, respectively. Optimal efficiency was obtained when: (1) the reporter cassette was upstream rather than downstream of the selectable marker cassette, (2) the puromycin rather than the neomycin resistance gene was used, (3) a 5' deletion (314 bp) was created in the PGK promoter, and (4) two copies of a 120-bp element derived from the hamster Aprt CpG island were introduced upstream of the EF1alpha promoter. In summary, we developed bicistronic and novel dual-promoter LVs that enable high and homogeneous expression of transgenes by polyclonal hESCs after antibiotic selection. These vectors may provide important tools for basic and applied research on hESCs.

Multiple adaptive mechanisms to chronic liver disease revealed at early stages of liver carcinogenesis in the Mdr2-knockout mice

Molecular events preceding the development of hepatocellular carcinoma were studied in the Mdr2-knockout (Mdr2-KO) mice. These mice lack the liver-specific P-glycoprotein responsible for phosphatidylcholine transport across the canalicular membrane. Portal inflammation ensues at an early age followed by hepatocellular carcinoma development after the age of 1 year. Liver tissue samples of Mdr2-KO mice in the early and late precancerous stages of liver disease were subjected to histologic, biochemical, and gene expression profiling analysis. In an early stage, multiple protective mechanisms were found, including induction of many anti-inflammatory and antioxidant genes and increase of total antioxidant capacity of liver tissue. Despite stimulation of hepatocyte DNA replication, their mitotic activity was blocked at this stage. In the late stage of the disease, although the total antioxidant capacity of liver tissue of Mdr2-KO mice was normal, and inflammation was less prominent, many protective genes remained overexpressed. Increased mitotic activity of hepatocytes resulted in multiple dysplastic nodules, some of them being steatotic. Expression of many genes regulating lipid and phospholipid metabolism was distorted, including up-regulation of choline kinase A, a known oncogene. Many other oncogenes, including cyclin D1, Jun, and some Ras homologues, were up-regulated in Mdr2-KO mice at both stages of liver disease. However, we found no increase of Ras activation. Our data suggest that some of the adaptive mechanisms induced in the early stages of hepatic disease, which protect the liver from injury, could have an effect in hepatocarcinogenesis at later stages of the disease in this hepatocellular carcinoma model.

The impact of an aging population on curriculum development in Canadian undergraduate nursing education

The rise in numbers of persons 65 years of age and older due to increased life expectancy is necessitating a revision in undergraduate nursing education. Since additional qualified nurses will be required to care for this expanding population, nursing programs must include sufficient relevant gerontological content delivered by competent faculty to prepare these practitioners. The authors review pertinent literature, present several surveys outlining the current status of gerontology content in nursing and other allied health programs, and argue for gerontological nursing to be a core component of undergraduate programs.

Analysis of differentially expressed genes in hepatocellular carcinoma using cDNA arrays

Hepatocellular carcinoma (HCC) is characterized by multiple somatic mutations, including DNA rearrangements, that affect many cell-growth regulatory pathways. Many genes differentially expressed in HCC have been reported previously, but the patterns of expression varied significantly between patients who bore different risk factors for HCC. To identify genes whose differential expression could serve as a "signature" for diagnosis and prognosis of HCC, we performed analyses of differentially expressed genes in three cases of HCC with different risk factors using the Atlas Human Cancer cDNA Expression Arrays. Among all 597 genes present on the array, only three were found to be coordinately differentially expressed in all three HCC cases, in agreement with published data. These three genes, Cu/Zn superoxide dismutase, osteonectin/secreted protein acidic and rich in cysteine, and matrix metalloproteinase 14, could serve as candidates for the HCC "signature." Ten genes were found to be coordinately differentially expressed in only two of three tested HCC cases. On the other hand, many genes that had been reported previously as differentially expressed in HCC failed to show the described pattern of expression in this group. The results of this study confirm the great variability in gene-expression patterns in HCC and establish the utility of the array technology for identifying both the HCC signature genes and individual gene-expression patterns for purposes of patient-oriented therapy.

The RUNX3 gene--sequence, structure and regulated expression

The RUNX3 gene belongs to the runt domain family of transcription factors that act as master regulators of gene expression in major developmental pathways. In mammals the family includes three genes, RUNX1, RUNX2 and RUNX3. Here, we describe a comparative analysis of the human chromosome 1p36.1 encoded RUNX3 and mouse chromosome 4 encoded Runx3 genomic regions. The analysis revealed high similarities between the two genes in the overall size and organization and showed that RUNX3/Runx3 is the smallest in the family, but nevertheless exhibits all the structural elements characterizing the RUNX family. It also revealed that RUNX3/Runx3 bears a high content of the ancient mammalian repeat MIR. Together, these data delineate RUNX3/Runx3 as the evolutionary founder of the mammalian RUNX family. Detailed sequence analysis placed the two genes at a GC-rich H3 isochore with a sharp transition of GC content between the gene sequence and the downstream intergenic region. Two large conserved CpG islands were found within both genes, one around exon 2 and the other at the beginning of exon 6. RUNX1, RUNX2 and RUNX3 gene products bind to the same DNA motif, hence their temporal and spatial expression during development should be tightly regulated. Structure/function analysis showed that two promoter regions, designated P1 and P2, regulate RUNX3 expression in a cell type-specific manner. Transfection experiments demonstrated that both promoters were highly active in the GM1500 B-cell line, which endogenously expresses RUNX3, but were inactive in the K562 myeloid cell line, which does not express RUNX3.

Synergistic necrotizing cellulitis as a complication of peritonsillar abscess

Peritonsillar abscess, a complication of tonsillitis, is not uncommon. The usual treatment consists of needle aspiration or surgical drainage and antibiotic treatment. Tonsillectomy may be used in the management of this condition, either at the time of diagnosis or after an interval period. Severe complications of peritonsillar abscess are rare. Synergistic necrotizing cellulitis is a fulminant infection associated with spread along fascial plains, necrosis of connective tissue and muscle, and high mortality. It is usually otondogenic in origin in the cervicofacial area and occurs in debilitated or immune compromised patients. We discuss cervicofacial-necrotizing soft tissue disease and report an unusual case of extensive synergistic necrotizing cellulitis of the neck, chest, and shoulder as a result of a peritonsillar abscess.

The association between iron-deficiency anemia and recurrent acute otitis media

PURPOSE

This study was designed to examine the association between iron-deficiency anemia and the frequency of recurrent acute otitis media in children, and to evaluate the effect of restoring normal hemoglobin levels on the frequency of acute otitis media attacks.

MATERIALS AND METHODS

A total of 680 children with frequent episodes of acute otitis media were enrolled in the study. The levels of the hemoglobin were measured in both these children and in 200 healthy children with no history of infections. The correlation between hemoglobin level and the frequency of middle ear infections was studied and analyzed. All children with hemoglobin levels lower than 9.5 g/dL received iron supplementation until they reached a level of at least 11 g/dL, and the subsequent frequency of middle ear infections was recorded.

RESULTS

The 680 children had an average of 8.3 +/- 2.7 episodes of acute otitis media per year per child, and an average hemoglobin level of 11.4 +/- 2.7 g/dL, whereas the controls had an average hemoglobin level of 13.1 +/- 2.5 g/dL. Twenty percent had hemoglobin levels below 9.5 g/dL. These children had more episodes of acute otitis media when compared with children with average levels. By increasing the hemoglobin level in these children, the frequency of the episodes of acute otitis media decreased significantly.

CONCLUSIONS

This study confirms that anemic children have higher prevalence of episodes of acute otitis media in comparison to healthy, nonanemic children, and shows that there is a direct relationship between the degree of the anemia and the number of the episodes.

What is chronic fatigue syndrome? Heterogeneity within an international multicentre study

OBJECTIVE

We sought to compare the characteristics of patients presenting with chronic fatigue (CF) and related syndromes in eight international centres and to subclassify these subjects based on symptom profiles. The validity of the subclasses was then tested against clinical data.

METHOD

Subjects with a clinical diagnosis of CF completed a 119-item self-report questionnaire to provide clinical symptom data and other information such as illness course and functional impairment. Subclasses were generated using a principal components-like analysis followed by latent profile analysis (LPA).

RESULTS

744 subjects returned complete data sets (mean age 40.8 years, mean length of illness 7.9 years, female to male ratio 3:1). Overall, the subjects had a high rate of reporting typical CF symptoms (fatigue, neuropsychological dysfunction, sleep disturbance). Using LPA, two subclasses were generated. Class one (68% sample) was characterized by: younger age, lower female to male ratio; shorter episode duration; less premorbid, current and familial psychiatric morbidity; and, less functional disability. Class two subjects (32%) had features more consistent with a somatoform illness. There was substantial variation in subclass prevalences between the study centres (Class two range 6-48%).

CONCLUSIONS

Criteria-based approaches to the diagnosis of CF and related syndromes do not select a homogeneous patient group. While substratification of patients is essential for further aetiological and treatment research, the basis for allocating such subcategories remains controversial.

Epstein-Barr virus and cancers of the head and neck

Denis Burkitt pioneered the association of viruses and cancer in humans with his observations of lymphomatous tumors in children in equatorial Africa. The Epstein-Barr virus (EBV), a human B lymphotrophic herpes virus, is strongly associated with undifferentiated carcinoma of the nasopharynx and African-type Burkitt's lymphoma. More recently, an association of this virus with other epithelial neoplasms, lymphomas, and immunodeficiency-related malignant and nonmalignant conditions has been reported. Since many of these tumors are rare, much of the information is based on sporadic reports and relatively small series of patients. The purpose of this report is to review the literature and examine the growing association of EBV with various head and neck malignancies.

The effects of noise on the vestibular system

PURPOSE

Subjects with noise-induced hearing loss sometimes also complain about balance disorders, but reports of clinical series that give contradictory results are highly controversial. This study was designed to evaluate the effects of intense noise on the vestibular labyrinth, both in subjects with symmetrical hearing loss and in subjects with asymmetrical loss, and to examine the correlation between the subjects' complaints and the results of the vestibular function tests.

METHODS

A total of 258 male military personnel, heavily exposed to various intense noises, were included in the study. They were divided into 2 groups according to their hearing; 134 had a symmetrical high-tone hearing loss, and 124 had asymmetrical losses. Each group was divided into 2 subgroups according to the presence or absence of vestibular complaints. All of the subjects underwent a complete audiological and electronystagmographic evaluation.

RESULTS

We found that vestibular damage caused by intense noise exposure might be expressed clinically in subjects with asymmetrical hearing loss. There was a strong correlation between the subjects' complaints and the results of the vestibular function tests. There was no correlation between the severity of the hearing loss and the vestibular symptomatology and pathology.

CONCLUSIONS

Subjects exposed to intense noise may have evidence of vestibular pathology only when there is an asymmetrical hearing loss. Whenever hearing loss is symmetrical, an equal damage to the vestibular system of both ears is most probably responsible for the absence of abnormal findings on the vestibular function tests. The results of this study have important medicolegal implications for individuals exposed to intense noises.

Malignant tumors of the nose and paranasal sinuses: a retrospective review of 291 cases

Malignant neoplasms of the nose and paranasal sinuses are not common among the general population. We present a retrospective study of 291 cases of malignant tumors of the nose and paranasal sinuses that were diagnosed in a northern Romanian population over a period of 35 years. We review the etiology, diagnosis, prognosis, and treatment of these tumors.

Acute mastoiditis--the antibiotic era: a multicenter study

OBJECTIVES

To evaluate the clinical course and identify the causative organisms of acute mastoiditis in a community where most of the patients who develop acute otitis media are treated with antibiotics.

METHODS

A multicenter retrospective review of a series of 223 consecutive cases of acute mastoiditis.

SETTING

Nine secondary or tertiary academic or non-academic referral centers.

RESULTS

Prior to the diagnosis of acute mastoiditis, 121 of the patients (54.3%) had been receiving oral antibiotic treatment for acute otitis media for periods ranging from 1 to 21 days (mean 5.3 days). Samples for bacterial culture were obtained from 152 patients. Cultures were negative in 60 patients. The organisms isolated in the 92 positive cultures were: Streptococcus pneumoniae (15 patients), Streptococcus pyogenes (14 patients), Staphylococcus aureus (13 patients), Staphylococcus coagulase negative (three patients), Pseudomonas aeruginosa (eight patients), Haemophilus influenzae (four patients), Proteus mirabilis (two patients), Escherichia coli (two patients), Klebsiella pneumoniae (one patient), Enterobacter (one patient), Acinetobacter (one patient), anaerobic gram-negative bacilli (one patient), and fungi (two patients). Ten patients had mixed flora. Sixteen patients presented with complications (cerebellar abscess, perisinus empyema, subdural abscess or empyema, extradural abscess, cavernous sinus thrombosis, lateral sinus thrombosis, bacterial meningitis, labyrinthitis, petrositis, or facial nerve palsy).

CONCLUSIONS

Antibiotic treatment cannot be considered an absolute safeguard against the development of acute mastoiditis. Early myringotomy for acute otitis media seems to decrease the incidence of complications. The distribution of causative organisms in acute mastoiditis differs from that in acute otitis media. Intracranial complications in acute mastoiditis are not rare. Because of the diversity of causative organisms in acute mastoiditis and the growing resistance of bacteria to the various antibiotics, all means to obtain a sample for culture prior to antibiotic treatment, including general anesthesia.

Laser partial epiglottidectomy as a treatment for obstructive sleep apnea and laryngomalacia

Obstructive sleep apnea (OSA) and laryngomalacia are two different entities. Occasionally, they may have a common etiology: an elongated, flaccid, and lax epiglottis that is displaced posteriorly during inspiration causing airway obstruction. Twenty-seven adults with a diagnosis of airway obstruction or OSA of various degrees, and 12 infants with severe stridor associated with frequent apneas due to laryngomalacia, who on fiberoptic examination were found to have a posteriorly displaced epiglottis, underwent partial epiglottidectomy with a CO2 laser. Their postoperative recovery was uneventful. Polysomnographic studies performed after operation in the adult patients demonstrated statistically significant improvement in 85% of the patients. In all the cases of laryngomalacia, stridor ceased permanently after surgery, together with complete cessation of the apneic episodes. This study demonstrates that similar pathophysiological mechanisms may be involved in both laryngomalacia and in OSA. Effective and relatively safe treatment can be achieved by partial resection of the epiglottis with a microlaryngoscopic CO2 laser.

Misplaced parotid glands: bilateral agenesis of parotid glands associated with bilateral accessory parotid tissue

Agenesis of the parotid is a rare entity. It is usually unilateral but bilateral cases have been described as a rare cause of xerostomia. Accessory parotid tissue is also uncommon and is not normally associated with aplasia of the parotid gland. The embryological, histological, clinical and radiological findings of these two entities will be discussed in addition to the report of an obscure case of bilateral parotid agenesis together with bilateral accessory parotid tissue.

Tracheotomy complications: a retrospective study of 1130 cases

BACKGROUND

Tracheotomy is one of the most frequently performed surgical procedures in the critically ill patient. It is frequently performed as an elective therapeutic procedure and only rarely as an emergency procedure. Complications occur in 5% to 40% of tracheotomies depending on study design, patient follow-up, and the definition of the different complications. The mortality rate of tracheotomy is less than 2%. Numerous studies demonstrate a greater complication and mortality rate in emergency situations, in severely ill patients, and in small children.

METHODS

A retrospective study of 1130 consecutive tracheotomies performed during 1 decade (January 1987 through December 1996) is presented. We studied the indications for surgery, the major complications of tracheotomy, and their treatment and outcome. We also noted the overall mortality rate and the specific complications that led to these deaths.

RESULTS

In total, 1130 tracheotomies were performed. Major complications occurred in 49 of the cases, and 8 deaths were directly attributed to the tracheotomy. The most common complication was tracheal stenosis, which occurred in 21 cases. Hemorrhage was the second most common complication, which occurred in 9 cases.

CONCLUSION

This is one of the largest series of consecutive tracheotomies compiled. We found a relatively low overall complication and mortality rate compared with other large series. Tracheal stenosis was the most common complication in contrast to other series. Our opinion is that this may reflect tracheal damage originally caused by prolonged intubation before the tracheotomy. We believe that all other complications of tracheotomy may be prevented or minimized by careful surgical technique and postoperative tracheotomy care.

The medical school Web site: medical education's newest tool

There are few technological advancements that have had as much impact on the dissemination of information as the Internet, and especially the worldwide web. It is not surprising then that this tool is also changing the way medicine is studied, taught and practiced today. This impressive infrastructure enables us to teach and study medicine in an entirely different way. The web provides medical students and physicians with access to continuing medical education, patient education services, telemedicine, and unparalleled communication between colleagues via email. The medical school web site may be used as a dynamic newspaper or bulletin board to disseminate information internally among the faculty as well as to the outside world. It can also be the vehicle for virtual learning modules that enhance the medical school core curriculum by including lectures, exercises, tests, etc. In addition, the web allows the student access to medical literature, medical software applications and medical resource depots. To date no work has been published on the medical school web site, its construction process, and its advantages, drawbacks and future. The purpose of this article is to examine the evolution of the web as a tool for medical schools, medical students and associated physicians. We discuss the building of a web site for a medical faculty, and look to the future.