Can colorectal cancer be prevented or treated by oral hormone replacement therapy?

Guanylyl cyclase C (GCC) is the receptor specifically expressed by intestinal cells for the paracrine hormones guanylin and uroguanylin and diarrheagenic bacterial heat-stable enterotoxins. This tissue-specific receptor coordinates lineage-dependent regulation of epithelial homeostasis, and its disruption contributes to intestinal tumorigenesis. It coordinates regenerative and metabolic circuits by restricting the cell cycle and proliferation and programming metabolic transitions central to organizing the dynamic crypt-surface axis. Further, mice deficient in GCC signaling are more susceptible to colon cancer induced by Apc mutations or the carcinogen azoxymethane. Moreover, guanylin and uroguanylin are gene products most commonly lost, early, in colon cancer in animals and humans. The role of GCC as a tumor suppressing receptor regulating proliferation and metabolism, together with the universal loss of guanylin and uroguanylin in tumorigenesis, suggests a model in which colorectal cancer is a paracrine hormone deficiency syndrome. In that context, activation of GCC reverses the tumorigenic phenotype by limiting growth of colorectal cancer cells by restricting progression through the G1/S transition and reprogramming metabolic circuits from glycolysis to oxidative phosphorylation, limiting bioenergetic support for rapid proliferation. These observations suggest a pathophysiological hypothesis in which GCC is a lineage-dependent tumor suppressing receptor coordinating proliferative homeostasis whose dysregulation through hormone loss contributes to neoplasia. The correlative therapeutic hypothesis suggests that colorectal cancer is a disease of hormone insufficiency that can be prevented or treated by oral supplementation with GCC ligands.

Specific immunotherapy suppresses Th2 responses via modulating TIM1/TIM4 interaction on dendritic cells

BACKGROUND

Specific immunotherapy (SIT) is the only curable remedy for allergic disorders currently; however, the underlying mechanism is not fully understood yet. This study aimed to elucidate the mechanism of SIT on suppressing TIM4 (T cell immunoglobulin mucin domain molecule 4) expression in dendritic cells (DCs) and modulating the skewed T helper 2 (Th2) responses in patients with airway allergy.

METHODS

Twenty patients with allergic rhinitis (AR) were treated with SIT for 3 months. Before and after SIT, the expression of TIM4 in peripheral DC and TIM1 in Th2 cells was examined. The role of Fc gamma receptor (FcgammaR) I and II in modulating the expression of TIM4 in DCs was investigated.

RESULTS

The interaction of TIM1/TIM4 played a critical role in sustaining the polarization status of Th2 cells in AR patients. Cross-linking FcgammaRI by antigen/IgG complexes increased the production of TIM4 by dendritic cells via upregulating tumor necrosis factor-alpha in DCs. Exposure to microbial products promoted the expression of FcgammaRI in DCs that further increased the expression of TIM4. Exposure to specific antigens alone upregulated the expression of FcgammaRII in DCs, that suppressed the expression of TIM4.

CONCLUSIONS

We conclude that SIT suppresses the skewed Th2 responses via disrupting the interaction of TIM1/TIM4 in antigen-specific Th2 cells.

Color Doppler twinkling artifact in fetuses with echogenic intracardiac foci: echocardiographic observation and clinical significance

OBJECTIVE

To evaluate echocardiographic characteristics and clinical relevance of color Doppler twinkling artifacts in fetuses with isolated echogenic intracardiac foci (EIF).

METHODS

This study included 50 fetuses with EIF, at 18-38 weeks of gestation. Echocardiographic examination, which was performed using a 1.0-5.0-MHz phased array probe, included gray-scale, color and spectral Doppler imaging. Twinkling artifacts were assessed using fetal color Doppler echocardiography on isolated EIF situated in the left and/or right ventricles. The prevalence, appearance and clinical relevance of the color Doppler twinkling artifacts were analyzed.

RESULTS

Eight of 50 fetuses with EIF (16%) showed color Doppler twinkling artifacts, which appeared as a rapidly changing color complex seen persistently behind the EIF. The spectra obtained in all eight with color Doppler artifacts were composed of straight vertical bands occurring in mid to late systole and early diastole. After birth, none of 50 fetuses with EIF had structural heart diseases or showed clinical signs of cardiac failure.

CONCLUSIONS

Color Doppler twinkling artifacts from isolated EIF occur in some fetuses and may be considered as an additional echocardiographic feature of EIF. Attention should be paid to the identification and interpretation of these artifacts so that they may be accurately distinguished from true color flow generated by atrioventricular valvular regurgitation jets.

Clinical analysis of systemic lupus erythematosus with gastrointestinal manifestations

Our objective was to analyse the clinical characteristics of systemic lupus erythematosus (SLE) patients with gastrointestinal manifestations. Medical charts of 177 hospitalized SLE patients were systematically reviewed, including demographic data, clinical features, laboratory findings, and treatments, as well as outcomes. Thirty-nine cases (22.0%) had SLE-related gastrointestinal manifestations, and in 12 cases (30.8%), gastrointestinal manifestations occurred as the initial symptoms. Twenty-five cases (64.1%) had abdominal pain, 22 cases (56.4%) had nausea and vomiting, 12 cases (30.8%) had diarrhea, and gastrointestinal hemorrhage occurred in three cases (7.7%). Protein losing enteropathy and intestinal pseudo-obstruction were the most common identifiable gastrointestinal complications, though other reasons such as superior mesenteric venous thrombosis, pancreatitis, peritonitis, and liver impairment could also occur in SLE. The incidences of Raynaud's phenomenon and pyeloureterectasis were significantly higher in patients with gastrointestinal complications than those without (p < 0.05). Multivariable analysis indicated Raynaud's phenomenon, decreased C3, CH50, and anti-neutrophil cytoplasmic antibody positivity were independent predictors of gastrointestinal involvements (p < 0.05). Gastrointestinal complications are common, diverse, and could be the initial and major manifestations of lupus. SLE patients who had Raynaud's phenomenon, hypocomplementemia and positive anti-neutrophil cytoplasmic antibody were at increasing risk of developing gastrointestinal complication.

Generation and analysis of 10 000 ESTs from the half-smooth tongue sole Cynoglossus semilaevis and identification of microsatellite and SNP markers

Three normalized cDNA libraries were constructed, two of which were constructed from reproductive tissues ovary and testis, and the other one from pooled immune tissues including head kidney, intestine, liver and spleen. A total of 10 542 clones were sequenced generating 10 128 expressed sequence tags (ESTs). Cluster analysis indicated a total of 5808 unique sequences including 1712 contigs and 4096 singletons. A total of 4249 (73%) of the unique ESTs had significant hits to the non-redundant protein database, 2253 of which were annotated using Gene Ontology (GO) terms. A total of 311 microsatellites (with 246 having sufficient flanking sequences for primer design) and 6294 putative SNPs were identified. These genome resources provide the material basis for future microarray development, marker validation and genetic linkage and QTL analysis.

Professionalism: the major factor influencing job satisfaction among Korean and Chinese nurses

BACKGROUND

The nursing shortage has become an internationally important issue. Nurses' professionalism and job satisfaction have been recognized as strong factors influencing their turnover. As international interchanges in nursing education are growing between Korea and China, understanding the commonalities and differences in factors associated with job satisfaction is critical to improving nurses' job retention.

AIM

To compare the factors influencing job satisfaction among Korean and Chinese nurses.

METHOD

A cross-sectional survey was conducted. The participants were comprised of 693 nurses at three general hospitals in Jinan, People's Republic of China and 593 nurses at two general hospitals in Seoul, Korea. A questionnaire was designed to measure the nurses' professionalism and job satisfaction. Stepwise multiple regression analysis was performed to identify factors related to job satisfaction.

RESULTS

Professionalism was the common factor influencing job satisfaction in Korean and Chinese nurses. Professionalism was positively related to job satisfaction in both groups. Additional factors associated with job satisfaction were demographics and job characteristics such as age, job position and department of work, which were significant only in Korean nurses.

CONCLUSIONS

Professionalism was the most important factor influencing job satisfaction in both Korean and Chinese nurses. Enhancing nursing professionalism is recommended as a common strategy to improve nurses' job retention across different healthcare systems.

Structural and energetic mechanisms of cooperative autoinhibition and activation of Vav1

Vav proteins are guanine nucleotide exchange factors (GEFs) for Rho family GTPases. They control processes including T cell activation, phagocytosis, and migration of normal and transformed cells. We report the structure and biophysical and cellular analyses of the five-domain autoinhibitory element of Vav1. The catalytic Dbl homology (DH) domain of Vav1 is controlled by two energetically coupled processes. The DH active site is directly, but weakly, inhibited by a helix from the adjacent Acidic domain. This core interaction is strengthened 10-fold by contacts of the calponin homology (CH) domain with the Acidic, pleckstrin homology, and DH domains. This construction enables efficient, stepwise relief of autoinhibition: initial phosphorylation events disrupt the modulatory CH contacts, facilitating phosphorylation of the inhibitory helix and consequent GEF activation. Our findings illustrate how the opposing requirements of strong suppression of activity and rapid kinetics of activation can be achieved in multidomain systems.

c-Abl and Arg tyrosine kinases regulate lysosomal degradation of the oncoprotein Galectin-3

Galectin-3 (Gal3) has important roles in tumor transformation and metastasis. This study shows that c-Abl and Abl-related gene (Arg) associate with and phosphorylate Gal3. The SH (Src homology)3 domains of c-Abl/Arg bind to a P(80)GPPSGP motif of Gal3, and Tyr79 and Tyr118 are the major tyrosine phosphorylation sites. A consequence of this interaction and phosphorylation is the significant impairment of chaperone-mediated autophagy of Gal3. Cells expressing Gal3 and treated with the c-Abl/Arg inhibitor STI571, Gal3-depleted cells, and Gal3-depleted cells expressing Gal3 phosphorylation mutants all display an increased sensitivity to apoptosis-inducing agents. In addition, tumor cells expressing the phosphorylation mutants show impaired tumorigenicity. These results partially explain the antiapoptotic effect of Abl and Arg. As tumors frequently overexpress Gal3, a c-Abl/Arg-specific inhibitor may potentially be applied along with other antitumor drugs to target the lysosomal degradation of Gal3 in tumor therapy.

Detection of PCR products using self-reporting duplex mutation primers

A novel oligonucleotide probe, with duplex mutation primers, which comprised a normal reverse primer labelled with a fluorophore at its 5'-end and a single-base mismatched complementary oligonucleotide labelled with a quencher at its 3'-end, was designed. Its application in the detection of hepatitis B virus (HBV) DNA of serum was investigated; results were compared with those obtained using a commercial TaqMan kit. There was a good linear correlation in the range of 10(2) approximately 10(7) copies/ml (r(2) = 0.999) with the method. Intra-experimental coefficients of variation (CVs) were 0.70% approximately 7.80%, and inter-experimental CVs were 0.78% approximately 9.02%, respectively. There was no significant difference of HBV genome number tested by the two methods (p<0.05) in 132 hepatitis B patients; HBV DNA was not detected in any serum samples of 20 healthy volunteers by the two methods.

Killing of Escherichia coli using the gas diffusion electrode system

To be best of our knowledge, this study is one of the first investigations to be performed into the potential benefits of gas diffusion electrode (GDE) system in controlling inactivation of E. coli. This study mainly focused on the dual electrodes disinfection with gas diffusion cathode, using Escherichia coli as the indicator microorganisms. The effects of Pt load W(Pt) and the pore-forming agent content W(NH(4)HCO(3)) in GDE, operating conditions such as pH value, oxygen flow rate Q(O(2)), salt content and current density on the disinfection were investigated, respectively. The experimental results showed that the disinfection improved with increasing Pt load W(Pt), but its efficiency at Pt load of 3 per thousand was equivalent to that at Pt load of 4 per thousand. Addition of the pore-forming agent in the appropriate amount improved the disinfection while drop of pH value resulted in the rapid rise of the germicidal efficacy and the disinfection shortened with increasing oxygen flow rate Q(O(2)). The system is more suitable for highly salt water. The germicidal efficacy increased with current density. However, the accelerating rate was different: it first increased with the current density, then decreased, and reached a maximum at current density of 6.7-8.3 mA/cm(2). The germicidal efficacy in the cathode compartment was about the same as in the anode compartment indicating the contribution of direct oxidation and indirect treatment of E. coli by the hydroxyl radical was similar to the oxidative indirect effect of the generated H(2)O(2). This technology is expensive in operating cost, further research is required to advance the understanding and reduce the operating cost of this technology.

66 ISOLATION, CHARACTERIZATION, AND NUCLEAR REPROGRAMMING OF STEM CELLS DERIVED FROM ADULT PORCINE LIVER AND FAT

Genetic manipulation of the porcine genome to produce genetically modified pigs for various biomedical and agriculture applications has been hampered by the lack of an ideal cell type that can grow in culture for a long period of time and is amenable to various genetic manipulations with high efficiency. The cell type currently used for various genetic manipulations is fetal fibroblast. These cells have very limited life span in culture and the efficiency of gene targeting is very low. There is no report of isolation of functional embryonic stem cells (ESC) from pig that would have been used to produce transgenic pigs with high efficiency as has been possible in mice. Recently, porcine induced pluripotent stem cells (iPSC) have been reported by 3 groups. However, they have yet to be tested for genetic manipulations and production of transgenic pigs. In this study, we developed a simple but novel strategy to recover stem cells from adult porcine liver and adipose tissues. Small colonies with few cells became visible as early as 2 to 3 days under reduced oxygen conditions on collagen-coated plates, and a full-grown colony with a fibroblast-like morphology took 10 to 14 days to form. Ten single colonies per tissue were isolated, subcultured, and monitored for growth and gene expression. Both of these cell types maintained steady growth through 70 population doublings (at the time of writing) and are still growing without any change in their morphology. Reverse transcription PCR was used to monitor gene expression. Both cell types show strong expression of c-Myc and KLF4. Moreover, low expression of Oct-4 and Lin28, 2 important genes related to pluripotency, was also detected in cells derived from adipose tissues, indicating that these cells could be easily reprogrammed to pluripotent state. These cells maintained a normal karyotype after long-term culture. Cell lines with stable genetic modifications and extended expression of transgene were obtained when these cells were transfected with a plasmid containing the neomycin resistance gene and selected under G418. Further, these 2 cell types, liver stem cells (LSC) and fat stem cells (FSC), and fetal fibroblasts (FF) as a control were used as nuclear donors to produce somatic cell nuclear transfer (SCNT) embryos. The average fusion rates were 87, 81, and 89% for LSC, FSC, and FF, respectively. Of 2 recipients receiving nuclear transfer embryos produced with each cell type, one established pregnancy at Day 30 (50%). Efficiencies were 5% (11 fetuses/223 embryos transferred), 1.8% (4 fetuses/228 embryos transferred),and 5% (11 fetuses/219 embryos transferred) for LSC, FSC, and FF, respectively. Thus, these adult liver and fat stem cells are attractive cell types for cloning valuable adult animals with high efficiency and for SCNT transgenesis.

GCC signaling in colorectal cancer: Is colorectal cancer a paracrine deficiency syndrome?

Guanylyl cyclase C (GCC) is the receptor expressed by intestinal cells for the paracrine hormones guanylin and uroguanylin that coordinate mucosal homeostasis and its silencing contributes to intestinal transformation. It orchestrates proliferative and metabolic circuits by limiting the cell cycle and programming metabolic transitions central to regeneration along the crypt-villus axis. Mice deficient in GCC are more susceptible to colon cancer induced by germline mutations or carcinogens. Moreover, guanylin and uroguanylin are the most commonly lost gene products in colon cancer. The role of GCC as a tumor suppressor and the universal loss of its hormones in transformation suggest a paradigm in which colorectal cancer is a disease of paracrine hormone insufficiency. Indeed, GCC signaling reverses the tumorigenic phenotype of human colon cancer cells by regulating proliferation and metabolism. These data suggest a pathophysiological hypothesis in which GCC is a tumor suppressor coordinating proliferative homeostasis whose silencing through hormone loss initiates transformation. The correlative therapeutic hypothesis suggests that colorectal cancer is a disease of hormone insufficiency that can be prevented or treated by oral hormone replacement therapy employing GCC ligands.