Endogenous hydrogen sulfide is involved in regulation of respiration in medullary slice of neonatal rats

The purpose of the present study was to verify our assumption that rhythmic respiratory activity may be regulated by endogenous hydrogen sulfide (H(2)S) in the medullary slices of neonatal rats. We found that a moderate concentration of donor of H(2)S, NaHS, mainly induced diphasic respiratory responses indicated by changes of discharge frequency (DF) of hypoglossal rootlets, an initial inhibitory stage followed by a later excitatory one. Cystathionine beta-synthase (CBS) substrate, cysteine (CYS), exerted similar effects. CBS inhibitor, NH(2)OH, could eliminate both inhibitory and excitatory effects in the two stages induced by CYS. K(ATP) channel blocker, glibenclamide (Gl), could eliminate the decrease in DF in the initial stage, but not the increase in the later one. On the other hand, adenyl cyclase (AC) inhibitor, SQ-22536 (SQ) could eliminate the increase in DF in the later stage, but not the decrease in the initial one, of the rootlets caused by NaHS. Co-application of Gl and SQ eliminated both inhibitory and excitatory effect induced by NaHS. The cAMP level was increased in the later stage but not in the initial one by NaHS, and the increase in the cAMP level could be eliminated by SQ. It can be concluded that the endogenous H(2)S could be produced through the CBS-H(2)S pathway and could be involved in the control of the central rhythmic respiration in the in vitro medullary slices of neonatal rats by opening K(ATP) channels and activating AC-cAMP pathway of the neurons.

Characterization of PacMetUT1, a recently isolated human prostate cancer cell line

BACKGROUND

Existing prostate cancer cell lines have limitations.

METHODS

Cells were characterized using Western blotting, immunohistochemistry, invasion into Matrigel, and by studying xenograft tumors.

RESULTS

We describe a cell line (PacMetUT1) isolated from a lymph node of a 57-year-old male with prostate cancer. Compared to existing prostate cancer cell lines, the growth rate of PacMetUT1 xenograft tumors is slower with tumors occurring at injection sites and with metastases to lung and liver. Androgen receptor (AR) was detected in vivo by Western blotting and the cells responded to methyltrienolone (R1881). PacMetUT1 cells are more invasive in Matrigel than DU-145, PC-3, and LNCaP cells, and showed greater anchorage-independent growth in soft agar. The cells do not express prostate specific antigen (PSA) in vitro or in xenografts. However, the green fluorescent protein (GFP) gene was introduced and stably expressed in PacMetUT1 cells, allowing tumor imaging in vivo. Xenograft tumors show epithelial features and are positive for keratin, epithelial membrane antigen, EGF receptor, and E cadherin. In contrast, fibroblast markers vimentin, desmin, and Factor VIII, were negative. Karyotyping showed losses of 6p, 7q, 8p, 18q, and 22q, and gains of 8q and 9q; additional genetic material was observed at 2q and 12p.

CONCLUSION

The PacMetUT1 cell line allows metastases to be assessed using a single animal model. Because of its slower growth, PacMetUT1 more closely mimics the human disease. Studies of tumor progression or metastasis can be conducted over a longer period of time.

Expression of claudin-2 in the multistage process of gastric carcinogenesis

OBJECTIVE

Claudin-2 is an important component of the tight junction (TJ) of epithelial cells, and its protein expression between many tumours is significantly different. It is unclear if Claudin-2 overexpression is a trigger or a consequence during carcinogenesis. The multistage tissues of gastric carcinogenesis provides us a valuable model for determining tumourigenicity.

METHODS

This paper investigated, for the first time, claudin-2 expression in the pathological paraffin tissues of sinus ventriculi from gastroscopic biopsy. To determine claudin-2 expression in gastric carcinogenesis by immunochemical ABC technique.

RESULTS

Altogether, 108 chronic superficial gastritis, 55 chronic atrophic gastritis, 109 intestinal-type metaplasia, 93 dysplasia and 52 gastric intestinal-type adenocarcinoma samples were analyzed. Results indicated that the percentage of claudin-2-positive cases was 0% for chronic superficial gastritis (0/108), 0% for chronic atrophic gastritis (0/55), 0% for intestinal-type metaplasia (0/109), 35.87% for dysplasia (33/92), and 73.47% for gastric intestinal-type adenocarcinoma (36/49) respectively, primarily in the cell membrane, and gradually increased in the multistage process of gastric carcinogenesis (P<0.001).

CONCLUSIONS

This suggests that claudin-2 protein overexpression may be closely correlated to gastric carcinogenesis.

Coherent optical OFDM: theory and design

Coherent optical OFDM (CO-OFDM) has recently been proposed and the proof-of-concept transmission experiments have shown its extreme robustness against chromatic dispersion and polarization mode dispersion. In this paper, we first review the theoretical fundamentals for CO-OFDM and its channel model in a 2x2 MIMO-OFDM representation. We then present various design choices for CO-OFDM systems and perform the nonlinearity analysis for RF-to-optical up-converter. We also show the receiver-based digital signal processing to mitigate self-phase-modulation (SPM) and Gordon-Mollenauer phase noise, which is equivalent to the midspan phase conjugation.

Factor analysis in the Genetics of Asthma International Network family study identifies five major quantitative asthma phenotypes

BACKGROUND

Asthma is a clinically heterogeneous disease caused by a complex interaction between genetic susceptibility and diverse environmental factors. In common with other complex diseases the lack of a standardized scheme to evaluate the phenotypic variability poses challenges in identifying the contribution of genes and environments to disease expression.

OBJECTIVE

To determine the minimum number of sets of features required to characterize subjects with asthma which will be useful in identifying important genetic and environmental contributors. Methods Probands aged 7-35 years with physician diagnosed asthma and symptomatic siblings were identified in 1022 nuclear families from 11 centres in six countries forming the Genetics of Asthma International Network. Factor analysis was used to identify distinct phenotypes from questionnaire, clinical, and laboratory data, including baseline pulmonary function, allergen skin prick test (SPT).

RESULTS

Five distinct factors were identified:(1) baseline pulmonary function measures [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)], (2) specific allergen sensitization by SPT, (3) self-reported allergies, (4) symptoms characteristic of rhinitis and (5) symptoms characteristic of asthma. Replication in symptomatic siblings was consistent with shared genetic and/or environmental effects, and was robust across age groups, gender, and centres. Cronbach's alpha ranged from 0.719 to 0.983 suggesting acceptable internal scale consistencies. Derived scales were correlated with serum IgE, methacholine PC(20), age and asthma severity (interrupted sleep). IgE correlated with all three atopy-related factors, the strongest with the SPT factor whereas severity only correlated with baseline lung function, and with symptoms characteristic of rhinitis and of asthma.

CONCLUSION

In children and adolescents with established asthma, five distinct sets of correlated patient characteristics appear to represent important aspects of the disease. Factor scores as quantitative traits may be better phenotypes in epidemiological and genetic analyses than those categories derived from the presence or absence of combinations of +ve SPTs and/or elevated IgE.

Circulating FGF-21 levels in normal subjects and in newly diagnose patients with Type 2 diabetes mellitus

Fibroplast growth factor (FGF-21) is a recently discovered metabolic regulator. Its pathophysiologic role in humans remains unknown. In this study, we have investigated whether or not plasma FGF-21 level was different in patients with type 2 diabetes mellitus (T2DM) and non-diabetic controls. We also assessed associations between plasma FGF-21 body composition and several metabolic parameters. Fasting FGF-21 levels were significantly increased in patients with T2DM compared with controls (1.82+/-0.65 VS. 1.53+/-0.60 microg/L, P<0.05). In T2DM patients, fasting plasma FGF-21 correlate negatively with fasting blood glucose ( R= -0.31, P<0.05). Multiple regression analysis showed that FBG, plasma insulin and HOMA (IS) were independent influencing plasma FGF-21 levels. The present work suggests a potential role for FGF-21 in the pathogenesis of insulin resistance and T2DM.

Effects of rapid antigen degradation and VEE glycoprotein specificity on immune responses induced by a VEE replicon vaccine

Genetic vaccines are engineered to produce immunogens de novo in the cells of the host for stimulation of a protective immune response. In some of these systems, antigens engineered for rapid degradation have produced an enhanced cellular immune response by more efficient entry into pathways for processing and presentation of MHC class I peptides. VEE replicon particles (VRP), single cycle vaccine vectors derived from Venezuelan equine encephalitis virus (VEE), are examined here for the effect of an increased rate of immunogen degradation on VRP vaccine efficacy. VRP expressing the matrix capsid (MA/CA) portion of SIV Gag were altered to promote rapid degradation of MA/CA by various linkages to co-translated ubiquitin or by destabilizing mutations and were used to immunize BALB/c mice for quantitation of anti-MA/CA cellular and humoral immune responses. Rapid degradation by the N-end rule correlated with a dampened immune response relative to unmodified MA/CA when the VRP carried a glycoprotein spike from an attenuated strain of VEE. In contrast, statistically equivalent numbers of IFNgamma(+)T-cells resulted when VRP expressing unstable MA/CA were packaged with the wild-type VEE glycoproteins. These results suggest that the cell types targeted in vivo by VRP carrying mutant or wild type glycoprotein spikes are functionally different, and are consistent with previous findings suggesting that wild-type VEE glycoproteins preferentially target professional antigen presenting cells that use peptides generated from the degraded antigen for direct presentation on MHC.

Endothelin-1 inhibits outward potassium currents in mouse outer sulcus cells

The outer sulcus cells are epithelial cells covering the luminal side of spiral sulcus of cochlea. It has been suggested that outer sulcus cells contribute to cation absorption from the lumen of the cochlea. We investigated the electrical properties and the effects of endothelin-1 (ET-1) on the outward potassium currents in mouse outer sulcus cells using a whole-cell patch clamp technique. The cell capacitance was 3.16+/-0.66 pF (n =35) and the resting membrane potential was -98.4+/-1.6 mV (n=6) in extracellular fluid bath solution. The outward K+ currents were activated by depolarizing pulses more positive than -60 mV, and was sensitive to TEA (10 mM). Tail current analysis revealed that it was primarily K+ selective. Application of ET-1 caused a decrease of outward potassium currents within seconds, whereas treatment with BQ123, a competitive inhibitor of the ET type-A receptor, counteracted the inhibitory effect of ET-1. These results suggest that ET-1 inhibits outward potassium currents through the activation of ET type-A receptor. ET-1 may play an important role in maintaining the ionic homeostasis of endolymph.

NF-kappaB activation as a key mechanism in ethanol-induced disruption of the F-actin cytoskeleton and monolayer barrier integrity in intestinal epithelium

Intestinal barrier disruption has been implicated in several intestinal and systemic disorders including alcoholic liver disease (ALD). Using monolayers of intestinal (Caco-2) cells, we showed that ethanol (EtOH) disrupts the barrier integrity via destabilization of the cytoskeleton. Because proinflammatory conditions are associated with activation of NF-kappa B (NF-kappaB), we hypothesized that EtOH induces disruption of cytoskeletal assembly and barrier integrity by activating NF-kappaB. Parental cells were pretreated with pharmacological modulators of NF-kappaB. Other cells were stably transfected with a dominant negative mutant for the NF-kappaB inhibitor, I-kappaBalpha. Monolayers of each cell type were exposed to EtOH and we then monitored monolayer barrier integrity (permeability); cytoskeletal stability and molecular dynamics (confocal microscopy and immunoblotting); intracellular levels of the I-kappaBalpha (immunoblotting); subcellular distribution and activity of NF-kappaB (immunoblotting and sensitive ELISA); and intracellular alterations in the 43kDa protein of the actin cytoskeleton, polymerized F-actin, and monomeric G-actin (SDS-PAGE fractionation). EtOH caused destabilizing alterations, including I-kappaBalpha degradation, NF-kappaB nuclear translocation, NF-kappaB subunit (p50 and p65) activation, actin disassembly (upward arrow G-, downward arrow F-), actin cytoskeleton instability, and barrier disruption. Inhibitors of NF-kappaB and stabilizers of I-kappaBalpha (e.g., MG-132, lactacystin, etc) prevented NF-kappaB activation while protecting against EtOH-induced injury. In transfected I-kappaBalpha mutant clones, stabilization of I-kappaBalpha to inactivate NF-kappaB protected against all measures of EtOH-induced injury. Our data support several novel mechanisms where NF-kappaB can affect the molecular dynamics of the F-actin cytoskeleton and intestinal barrier integrity under conditions of EtOH injury. (1) EtOH induces disruption of the F-actin cytoskeleton and of intestinal barrier integrity, in part, through I-kappaBalpha degradation and NF-kappaB activation; (2) The mechanism underlying this pathophysiological effect of the NF-kappaB appears to involve instability of the assembly of the subunit components of actin network.

Theoretical and experimental study on PMD-supported transmission using polarization diversity in coherent optical OFDM systems

In this paper, we conduct theoretical and experimental study on the PMD-supported transmission with coherent optical orthogonal frequency-division multiplexing (CO-OFDM). We first present the model for the optical fiber communication channel in the presence of the polarization effects. It shows that the optical fiber channel model can be treated as a special kind of multiple-input multiple-output (MIMO) model, namely, a two-input two-output (TITO) model which is intrinsically represented by a two-element Jones vector familiar to the optical communications community. The detailed discussions on various coherent optical MIMO-OFDM (CO-MIMO-OFDM) models are presented. Furthermore, we show the first experiment of polarization-diversity detection in CO-OFDM systems. In particular, a CO-OFDM signal at 10.7 Gb/s is successfully recovered after 900 ps differential-group-delay (DGD) and 1000-km transmission through SSMF fiber without optical dispersion compensation. The transmission experiment with higher-order PMD further confirms the immunity of the CO-OFDM signal to PMD in the transmission fiber. The nonlinearity performance of PMD-supported transmission is also reported. For the first time, nonlinear phase noise mitigation based on receiver digital signal processing is experimentally demonstrated for CO-OFDM transmission.

Relation of cognitive activity to risk of developing Alzheimer disease

BACKGROUND

Frequent cognitive activity in old age has been associated with reduced risk of Alzheimer disease (AD), but the basis of the association is uncertain.

METHODS

More than 700 old people underwent annual clinical evaluations for up to 5 years. At baseline, they rated current and past frequency of cognitive activity with the current activity measure administered annually thereafter. Those who died underwent a uniform postmortem examination of the brain. Amyloid burden, density of tangles, and presence of Lewy bodies were assessed in eight brain regions and the number of chronic cerebral infarctions was noted.

RESULTS

During follow-up, 90 people developed AD. More frequent participation in cognitive activity was associated with reduced incidence of AD (HR = 0.58; 95% CI: 0.44, 0.77); a cognitively inactive person (score = 2.2, 10th percentile) was 2.6 times more likely to develop AD than a cognitively active person (score = 4.0, 90th percentile). The association remained after controlling for past cognitive activity, lifespan socioeconomic status, current social and physical activity, and low baseline cognitive function. Frequent cognitive activity was also associated with reduced incidence of mild cognitive impairment and less rapid decline in cognitive function. Among 102 persons who died and had a brain autopsy, neither global nor regionally specific measures of neuropathology were related to level of cognitive activity before the study, at study onset, or during the course of the study.

CONCLUSION

Level of cognitively stimulating activity in old age is related to risk of developing dementia.

Haploinsufficiency of CDK4 prevents hepatocarcinogenesis in mice deficient in ELF, a mediator of TGF-beta signaling

10608

Background: The transforming growth factor-β (TGF-β) has a dual role in cancer, but in the prevention of tumorigenesis, TGF-β signaling inhibits cell cycle progression through an increase in cell cycle inhibitors and decrease in cell cycle activators. The adaptor protein embryonic liver fodrin (ELF) is crucial for normal TGF-β signaling. ELF facilitates the association and nuclear translocation of the TGF-β signaling proteins, Smad3 and Smad4. We have demonstrated that elf± mice develop hepatocellular cancers (HCC) spontaneously within 12 months. We have also shown that most human HCCs demonstrate a decreased expression of ELF. Our goal was to assess the interaction between ELF and cyclin dependent kinase 4 (CDK4), which is overexpressed in most human cancers. Methods: We compared the expression of CDK4 and ELF by immunohistochemistry and analyzed the interaction between CDK4 and ELF, in vitro by immunoprecitpitation and western blot. Finally, we assessed the development of HCC in intercrossed elf± and CDK4+/neo mice. Results: CDK4 and ELF expression are inversely correlated in HCCs from elf± mice. Furthermore, ELF interacts with CDK4 by forming a complex that includes Smad3 in COS-7 and HepG2 cells. ELF is phosphorylated upon overexpression of CDK4, revealing a possible mechanism by which CDK4 may inhibit ELF-dependent TGF-β signaling. To further assess whether the development of HCC in elf± mice is dependent upon CDK4 expression, we have intercrossed elf± and CDK4+/neo mice. At 12 months, only 17% of the elf±/CDK4+/neo mice developed HCC, compared to 40% of our historical control elf± mice. This initial data strongly suggests that haploinsufficiency of CDK4 can prevent the HCCs seen in elf± mice, and provides the genetic foundation for further exploring the benefits of specific inhibitors of CDK4 in the treatment of HCC. Conclusions: These results demonstrate the molecular interactions between ELF and CDK4, and suggest a mechanism by which CDK4 may render cells unresponsive to the growth inhibitory effects of TGF-β signaling. Furthermore, haploinsufficiency of CDK4 prevents the formation of HCC, and thus targeted-inhibition of CDK4 activity may be a logical treatment for HCC in humans.

No significant financial relationships to disclose.