Primary structure and functional expression from complementary DNA of a brain calcium channel

The primary structure of a voltage-dependent calcium channel from rabbit brain has been deduced by cloning and sequencing the complementary DNA. Calcium channel activity expressed from the cDNA is dramatically increased by coexpression of the alpha 2 and beta subunits, known to be associated with the dihydropyridine receptor. This channel is a high voltage-activated calcium channel that is insensitive both to nifedipine and to omega-conotoxin. We suggest that it is expressed predominantly in cerebellar Purkinje cells and granule cells.

HCV-related fibrosis progression following liver transplantation: increase in recent years

BACKGROUND/AIMS

The natural history and predictors of HCV-related disease severity post-transplantation are uncertain. The aims of this study were to define the natural history of post-transplantation HCV infection by assessing the rate of fibrosis progression, to determine if the post-transplantation natural history differs from that observed pre-transplantation, and to identify predictors of post-transplantation disease progression.

METHODS

Post-transplantation biopsies (mean: 3+/-1.6/patient) from 284 patients were scored according to histologic stage, using the method of Desmet et al. Change in fibrosis score (fibrosis progression/year) post-transplantation was used as the primary outcome. Predictors analyzed included viral factors (genotype and viral load at transplantation), patient demographics, year of transplantation, country of transplantation, pre-transplantation fibrosis progression, immunosuppression and laboratory data.

RESULTS

There was a linear association between change in fibrosis score and time from transplantation, with a median rate of fibrosis progression per year of 0.3 (0.004-2.19/year). Using parametric time-to-event analysis, the expected median duration to cirrhosis was 10 years. The rate of post-transplantation fibrosis progression was significantly higher than pre-transplantation (0.2/year (0.09-0.8) p<0.0001), and higher in Spanish than US centers (0.48 (0.01-2.19) vs 0.28 (0.004-2.08); p=0.09) despite similar progression rates prior to transplantation. Variables independently associated with post-transplantation progression included year of transplantation (p=0.0001), race (p=0.02), number of methyl-prednisolone boluses (p=0.03), and HCV RNA levels at transplantation (p=0.01).

CONCLUSIONS

HCV-related disease progression is accelerated in immunocompromised compared to immunocompetent patients, with a progressive increase in patients who have recently undergone liver transplantation. Changes in patient management post-transplantation over time and between transplant centers may account for the increase in fibrosis progression observed in recent years.

Histone deacetylases induce angiogenesis by negative regulation of tumor suppressor genes

Low oxygen tension influences tumor progression by enhancing angiogenesis; and histone deacetylases (HDAC) are implicated in alteration of chromatin assembly and tumorigenesis. Here we show induction of HDAC under hypoxia and elucidate a role for HDAC in the regulation of hypoxia-induced angiogenesis. Overexpressed wild-type HDAC1 downregulated expression of p53 and von Hippel-Lindau tumor suppressor genes and stimulated angiogenesis of human endothelial cells. A specific HDAC inhibitor, trichostatin A (TSA), upregulated p53 and von Hippel-Lindau expression and downregulated hypoxia-inducible factor-1alpha and vascular endothelial growth factor. TSA also blocked angiogenesis in vitro and in vivo. TSA specifically inhibited hypoxia-induced angiogenesis in the Lewis lung carcinoma model. These results indicate that hypoxia enhances HDAC function and that HDAC is closely involved in angiogenesis through suppression of hypoxia-responsive tumor suppressor genes.

Fear-potentiated startle: a neural and pharmacological analysis

The fear-potentiated startle paradigm has proven to be a useful system with which to analyze neural systems involved in fear and anxiety. This test measures conditioned fear by an increase in the amplitude of a simple reflex (the acoustic startle reflex) in the presence of a cue previously paired with a shock. Fear-potentiated startle is sensitive to a variety of drugs such as diazepam, morphine, and buspirone that reduce anxiety in people and can be measured reliably in humans when the eyeblink component of startle is elicited at a time when they are anticipating a shock. Electrical stimulation techniques suggest that a visual conditioned stimulus ultimately alters acoustic startle at a specific point along the acoustic startle pathway. The lateral, basolateral and central amygdaloid nuclei and the caudal branch of the ventral amygdalofugal pathway projecting to the brainstem are necessary for potentiated startle to occur. The central nucleus of the amygdala projects directly to one of the brainstem nuclei critical for startle and electrical stimulation of this nucleus increases startle amplitude. Chemical or electrolytic lesions of either the central nucleus or the lateral and basolateral nuclei of the amygdala block the expression of fear-potentiated startle. The perirhinal cortex, which projects directly to the lateral and basolateral amygdaloid nuclei, plays a critical role in the expression of fear-potentiated startle using either visual or auditory conditioned stimuli. These latter amygdaloid nuclei may actually be the site of plasticity for fear conditioning, because local infusion of the NMDA antagonist AP5 into these nuclei blocks the acquisition of fear-potentiated startle. On the other hand, the expression of fear-potentiated startle is blocked by local infusion of the non-NMDA ionotropic antagonist CNQX or the G-protein inactivating toxin, pertussis toxin, but not by AP5. Finally, we have begun to investigate brain systems that might be involved in the inhibition of fear. Local infusion of AP5 into the amygdala was found to block the acquisition of experimental extinction, a prototypical method for reducing fear. We have also established a reliable procedure for producing both external and conditioned inhibition of fear-potentiated startle and hope to eventually understand the neural systems involved in these phenomena.

Roles for Nkx3.1 in prostate development and cancer

In aging men, the prostate gland becomes hyperproliferative and displays a propensity toward carcinoma. Although this hyperproliferative process has been proposed to represent an inappropriate reactivation of an embryonic differentiation program, the regulatory genes responsible for normal prostate development and function are largely undefined. Here we show that the murine Nkx3.1 homeobox gene is the earliest known marker of prostate epithelium during embryogenesis and is subsequently expressed at all stages of prostate differentiation in vivo as well as in tissue recombinants. A null mutation for Nkx3.1 obtained by targeted gene disruption results in defects in prostate ductal morphogenesis and secretory protein production. Notably, Nkx3.1 mutant mice display prostatic epithelial hyperplasia and dysplasia that increases in severity with age. This epithelial hyperplasia and dysplasia also occurs in heterozygous mice, indicating haploinsufficiency for this phenotype. Because human NKX3.1 is known to map to a prostate cancer hot spot, we propose that NKX3.1 is a prostate-specific tumor suppressor gene and that loss of a single allele may predispose to prostate carcinogenesis. The Nkx3.1 mutant mice provide a unique animal model for examining the relationship between normal prostate differentiation and early stages of prostate carcinogenesis.

Clinical significance of intra-amniotic inflammation in patients with preterm labor and intact membranes

OBJECTIVE

The purpose of this study was to determine the frequency and clinical significance of intraamniotic inflammation in patients with preterm labor and intact membranes.

STUDY DESIGN

Amniocentesis was performed in 206 patients with preterm labor and intact membranes. Amniotic fluid was cultured for aerobic and anaerobic bacteria and mycoplasmas. The diagnosis of intraamniotic inflammation was made in patients with a negative amniotic fluid culture on the basis of amniotic fluid concentrations of interleukin-6 (>2.6 ng/mL, derived from receiver operating characteristic curve analysis). Statistical analysis was conducted with contingency tables and survival techniques.

RESULTS

Intra-amniotic inflammation (negative amniotic fluid culture but elevated amniotic fluid interleukin-6) was more common than intra-amniotic infection (positive amniotic fluid culture regardless of amniotic fluid interleukin-6 concentration; 21% [44/206 women] vs 10% [21/206 women]; P <.001). The amniocentesisto-delivery interval was significantly shorter in patients with intra-amniotic inflammation than in patients with a negative culture and without an inflammation (median, 20 hours [range, 0.1-2328 hours] vs median, 701 hours [range, 0.1-3252 hours], respectively; P <.0001). Spontaneous preterm delivery of <37 weeks was more frequent in patients with intra-amniotic inflammation than in those with a negative culture and without inflammation (98% vs 35%; P <.001). Patients with intra-amniotic inflammation had a significantly higher rate of adverse outcome than patients with a negative culture and without intra-amniotic inflammation. Adverse outcomes included clinical and histologic chorioamnionitis, funisitis, early preterm birth, and significant neonatal morbidity. There were no significant differences in the rate of adverse outcomes between patients with a negative culture but with intra-amniotic inflammation and patients with intra-amniotic infection (positive culture regardless of amniotic fluid interleukin-6 concentration).

CONCLUSION

Intra-amniotic inflammation/infection complicates one third of the patients with preterm labor (32%; 65/206 women), and its presence is a risk factor for adverse outcome. The outcome of patients with microbiologically proven intra-amniotic infection is similar to that of patients with intra-amniotic inflammation and a negative amniotic fluid culture. We propose that the treatment of patients in preterm labor be based on the operational diagnosis of intra-amniotic inflammation rather than the diagnosis of intra-amniotic infection because the latter diagnosis cannot be undertaken rapidly.

Structure-activity analysis of buforin II, a histone H2A-derived antimicrobial peptide: the proline hinge is responsible for the cell-penetrating ability of buforin II

Buforin II is a 21-aa potent antimicrobial peptide that forms, in a hydrophobic medium, an amphipathic structure consisting of an N-terminal random coil region (residues 1-4), an extended helical region (residues 5-10), a hinge (residue 11), and a C-terminal regular alpha-helical region (residues 12-21). To elucidate the structural features of buforin II that are required for its potent antimicrobial activity, we synthesized a series of N- and C-terminally truncated or amino acid-substituted synthetic buforin II analogs and examined their antimicrobial activity and mechanism of action. Deletion of the N-terminal random coil region increased the antibacterial activity approximately 2-fold, but further N-terminal truncation yielded peptide analogs with progressively decreasing activity. Removal of four amino acids from the C-terminal end of buforin II resulted in a complete loss of antimicrobial activity. The substitution of leucine for the proline hinge decreased significantly the antimicrobial activity. Confocal fluorescence microscopic studies showed that buforin II analogs with a proline hinge penetrated the cell membrane without permeabilization and accumulated in the cytoplasm. However, removal of the proline hinge abrogated the ability of the peptide to enter cells, and buforin II analogs without a proline hinge localized on the cell surface, permeabilizing the cell membrane. In addition, the cell-penetrating efficiency of buforin II and its truncated analogs, which depended on the alpha-helical content of the peptides, correlated linearly with their antimicrobial potency. Our results demonstrate clearly that the proline hinge is responsible for the cell-penetrating ability of buforin II, and the cell-penetrating efficiency determines the antimicrobial potency of the peptide.

Mechanotransduction in response to shear stress. Roles of receptor tyrosine kinases, integrins, and Shc

Shear stress, the tangential component of hemodynamic forces, activates many signal transduction pathways in vascular endothelial cells. The conversion of mechanical stimulation into chemical signals is still unclear. We report here that shear stress (12 dynes/cm2) induced a rapid and transient tyrosine phosphorylation of Flk-1 and its concomitant association with the adaptor protein Shc; these are accompanied by a concurrent clustering of Flk-1, as demonstrated by confocal microscopy. Our results also show that shear stress induced an association of alphavbeta3 and beta1 integrins with Shc, and an attendant association of Shc with Grb2. These associations are sustained, in contrast to the transient Flk-1. Shc association in response to shear stress and the transient association between alphavbeta3 integrin and Shc caused by cell attachment to substratum. Shc-SH2, an expression plasmid encoding the SH2 domain of Shc, attenuated shear stress activation of extracellular signal-regulated kinases and c-Jun N-terminal kinases, and the gene transcription mediated by the activator protein-1/12-O-tetradecanoylphorbol-13-acetate-responsive element complex. Our results indicate that receptor tyrosine kinases and integrins can serve as mechanosensors to transduce mechanical stimuli into chemical signals via their association with Shc.

Recurrent and acquired hepatitis C viral infection in liver transplant recipients

To examine the postliver transplant recurrence of hepatitis C virus (HCV) infection in patients with pretransplant infection, as well as its acquisition in patients without prior infection, we used the polymerase chain reaction to amplify HCV RNA in serum and/or liver samples of 89 patients with alcoholic and cryptogenic cirrhosis undergoing liver transplantation. Results were correlated with histologic findings from posttransplant liver biopsies. Ninety-five percent of patients with pretransplant infection had posttransplant viremia. In contrast, 35% of patients without pretransplant infection acquired the virus (P less than 0.0001). Pretransplant HCV infection predisposed patients to hepatitis in the new graft. HCV RNA was present in serum of 96% of patients with posttransplant hepatitis. Fifty-six percent of patients with posttransplant HCV infection had no evidence of liver damage at least 1 year posttransplant. However, of those patients with histologic hepatitis, chronic active hepatitis was common. It is concluded that although HCV infection recurs posttransplant in almost all infected patients, acquisition of the HCV infection with transplant is common. Pretransplant HCV infection is an independent risk factor for the development of posttransplant hepatitis. HCV infection accounts for the majority of posttransplant hepatitis not due to cytomegalovirus, and although many patients with posttransplant viremia have little evidence of histologic hepatitis, significant hepatic damage may occur.

Opposing effects of Ctk1 kinase and Fcp1 phosphatase at Ser 2 of the RNA polymerase II C-terminal domain

The C-terminal domain (CTD) of the RNA polymerase II (Pol II) largest subunit is hyperphosphorylated during transcription. Using an in vivo cross-linking/chromatin immunoprecipitation assay, we found previously that different phosphorylated forms of RNA Pol II predominate at different stages of transcription. At promoters, the Pol II CTD is phosphorylated at Ser 5 by the basal transcription factor TFIIH. However, in coding regions, the CTD is predominantly phosphorylated at Ser 2. Here we show that the elongation-associated phosphorylation of Ser 2 is dependent upon the Ctk1 kinase, a putative yeast homolog of Cdk9/P-TEFb. Furthermore, mutations in the Fcp1 CTD phosphatase lead to increased levels of Ser 2 phosphorylation. Both Ctk1 and Fcp1 cross-link to promoter and coding regions, suggesting that they associate with the elongating polymerase. Both Ctk1 and Fcp1 have been implicated in regulation of transcription elongation. Our results suggest that this regulation may occur by modulating levels of Ser 2 phosphorylation, which in turn, may regulate the association of elongation factors with the polymerase.

A C-terminal fragment of Agouti-related protein increases feeding and antagonizes the effect of alpha-melanocyte stimulating hormone in vivo

Agouti-related protein (Agrp) is present in rat and human hypothalamus and is structurally related to agouti protein. Overexpression of either of these proteins results in obesity. However the effect of exogenous Agrp and its in vivo interaction with alpha-melanocyte stimulating hormone (alphaMSH), the likely endogenous melanocortin 3 and 4 receptor (MC3-R and MC4-R) agonist, have not been demonstrated. We report that 1 nmol of Agrp(83-132), a C-terminal fragment of Agrp, when administered intracerebroventricularly (ICV) into rats, increased food intake over a 24-h period (23.0+/-1.4 g saline vs 32.9+/-2.3 g Agrp, p<0.05). The hyperphagia was similar to that seen when 1 nmol of the synthetic MC3-R and MC4-R antagonist SHU9119 was given i.c.v. (19.6+/-1.8 g saline vs 32.5+/-1.7 g SHU9119, p<0.001). Both Agrp(83-132) and SHU9119 blocked the reduction in 1-h food intake of i.c.v. alphaMSH at the beginning of the dark phase. This effect occurred independently of whether the antagonists were administered simultaneously, or nine hours prior, to the alphaMSH. We have also shown Agrp(83-132) is an antagonist at the MC3-R and MC4-R, with similar inhibition of cAMP activation to that previously reported for the full length peptide. In conclusion, Agrp(83-132) administered i.c.v. increases feeding with long lasting effects and is able to inhibit the action of alphaMSH. This interaction may be mediated by the MC3-R and/or MC4-R.

The relationship among inflammatory lesions of the umbilical cord (funisitis), umbilical cord plasma interleukin 6 concentration, amniotic fluid infection, and neonatal sepsis

OBJECTIVE

The purpose of this study was to determine whether funisitis (inflammation of the umbilical cord detected by histologic examination of the placenta) is associated with changes in the umbilical cord plasma concentration of interleukin 6, microbial invasion of the amniotic cavity, and neonatal sepsis.

STUDY DESIGN

The relationship among the presence of funisitis, interleukin 6 concentrations in umbilical cord plasma at birth, the results of amniotic fluid culture performed within 3 days of birth, and the occurrence of congenital neonatal sepsis was examined in 315 consecutive singleton preterm births (20-35 weeks' gestation). Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton jelly. The interleukin 6 concentration was measured with a specific immunoassay. Amniocentesis was performed in 106 patients within 3 days of birth. Amniotic fluid was cultured for aerobic and anaerobic bacteria and for mycoplasmas.

RESULTS

(1) Funisitis was present in 25% of patients (78/315). (2) Patients with funisitis had a significantly higher median cord plasma interleukin 6 and a lower gestational age at birth than did those without funisitis (cord interleukin 6: median, 52.4 pg/mL; range, 0.9-19,230 pg/mL; vs median, 4.6 pg/mL; range, 0-18,108 pg/mL; gestational age: median, 31.1 weeks' gestation; range, 21.0-35.0 weeks' gestation; vs median, 32.9 weeks' gestation; range, 21.4-35.0 weeks' gestation; P<.001 for each comparison). (3) A cord plasma interleukin 6 of > or =17.5 pg/mL had a sensitivity of 70% and a specificity of 78% in the identification of funisitis. (4) Microbial invasion of the amniotic cavity and clinical chorioamnionitis were more common among patients with funisitis than among those without funisitis (positive amniotic fluid culture: 53% [20/38]; vs. 12% [8/68]; clinical chorioamnionitis: 18% [14/78]; vs. 4% [9/237]; P<.001 for each comparison). (5) Neonates with funisitis had a significantly higher rate of congenital sepsis than did those without this lesion (12% [8/66] vs. 1% [3/216]; P<.001); this difference remained significant after adjustment for gestational age at birth (odds ratio, 7.2; 95% confidence interval, 1.8-29.0).

CONCLUSION

(1) Umbilical cord plasma interleukin 6 concentrations were higher in neonates born with funisitis than in those without this lesion. (2) Funisitis is associated with amniotic fluid infection, congenital neonatal sepsis, and the fetal inflammatory response syndrome.

Fluid shear stress activation of focal adhesion kinase. Linking to mitogen-activated protein kinases

Shear stress, the tangential component of hemodynamic forces, activates the extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) signal transduction pathways in cultured vascular endothelial cells to induce the transcriptional activation of many immediate early genes. It appears that integrins, protein-tyrosine kinases, and the structural integrity of actin are important factors involved in these shear stress-induced responses. The underlying molecular events were investigated by the application of a shear stress of 12 dyn/cm2 on bovine aortic endothelial cells (BAEC). We found that such a shear stress increased the tyrosine phosphorylation and the kinase activity of focal adhesion kinase (FAK) and its association with growth factor receptor binding protein 2 (Grb2) in a rapid and transient manner, suggesting that FAK may be linked to these mitogen-activated protein kinase signaling pathways through a Grb2. Son of sevenless (Sos) complex. FAK(F397Y), which encodes a dominant negative mutant of FAK, attenuated the shear stress-induced kinase activity of Myc epitope-tagged ERK2 and hemagglutinin epitope-tagged JNK1. DeltamSos1, encoding a dominant negative mutant of Sos in which the guanine nucleotide exchange domain has been deleted, also attenuated shear stress activation of Myc-ERK2 and hemagglutinin-JNK1. Pretreating the confluent BAEC monolayers with a blocking type anti-vitronectin receptor monoclonal antibody had similar inhibitory effects in these shear stress-activated ERKs and JNKs. Confocal microscopic observation further demonstrated that FAK tended to cluster with vitronectin receptor near the abluminal side of the sheared BAEC. These results demonstrate that FAK signaling is critical in the shear stress-induced dual activation of ERK and JNK.

Nanoscale nuclear magnetic resonance with a nitrogen-vacancy spin sensor

Extension of nuclear magnetic resonance (NMR) to nanoscale samples has been a longstanding challenge because of the insensitivity of conventional detection methods. We demonstrated the use of an individual, near-surface nitrogen-vacancy (NV) center in diamond as a sensor to detect proton NMR in an organic sample located external to the diamond. Using a combination of electron spin echoes and proton spin manipulation, we showed that the NV center senses the nanotesla field fluctuations from the protons, enabling both time-domain and spectroscopic NMR measurements on the nanometer scale.

EGCG, a major component of green tea, inhibits tumour growth by inhibiting VEGF induction in human colon carcinoma cells

Catechins are key components of teas that have antiproliferative properties. We investigated the effects of green tea catechins on intracellular signalling and VEGF induction in vitro in serum-deprived HT29 human colon cancer cells and in vivo on the growth of HT29 cells in nude mice. In the in vitro studies, (-)-epigallocatechin gallate (EGCG), the most abundant catechin in green tea extract, inhibited Erk-1 and Erk-2 activation in a dose-dependent manner. However, other tea catechins such as (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epicatechin (EC) did not affect Erk-1 or 2 activation at a concentration of 30 microM. EGCG also inhibited the increase of VEGF expression and promoter activity induced by serum starvation. In the in vivo studies, athymic BALB/c nude mice were inoculated subcutaneously with HT29 cells and treated with daily intraperitoneal injections of EC (negative control) or EGCG at 1.5 mg day(-1)mouse(-1)starting 2 days after tumour cell inoculation. Treatment with EGCG inhibited tumour growth (58%), microvessel density (30%), and tumour cell proliferation (27%) and increased tumour cell apoptosis (1.9-fold) and endothelial cell apoptosis (3-fold) relative to the control condition (P< 0.05 for all comparisons). EGCG may exert at least part of its anticancer effect by inhibiting angiogenesis through blocking the induction of VEGF.

Occurrence and fate of antibiotic, analgesic/anti-inflammatory, and antifungal compounds in five wastewater treatment processes

The presence of pharmaceuticals and personal care products (PPCPs) in the aquatic environment as a result of wastewater effluent discharge is a concern in many countries. In order to expand our understanding on the occurrence and fate of PPCPs during wastewater treatment processes, 62 antibiotic, analgesic/anti-inflammatory, and antifungal compounds were analyzed in 72 liquid and 24 biosolid samples from six wastewater treatment plants (WWTPs) during the summer and winter seasons of 2010-2012. This is the first scientific study to compare five different wastewater treatment processes: facultative and aerated lagoons, chemically-enhanced primary treatment, secondary activated sludge, and advanced biological nutrient removal. PPCPs were detected in all WWTP influents at median concentrations of 1.5 to 92,000 ng/L, with no seasonal differences. PPCPs were also found in all final effluents at median levels ranging from 3.6 to 4,200 ng/L with higher values during winter (p<0.05). Removal efficiencies ranged between -450% and 120%, depending on the compound, WWTP type, and season. Mass balance showed that the fate of analgesic/anti-inflammatory compounds was predominantly biodegradation during biological treatment, while antibiotics and antifungal compounds were more likely to sorb to sludge. However, some PPCPs remained soluble and were detected in effluent samples. Overall, this study highlighted the occurrence and behavior of a large set of PPCPs and determined how their removal is affected by environmental/operational factors in different WWTPs.

Wild-type and mutant huntingtins function in vesicle trafficking in the secretory and endocytic pathways

Huntingtin is a cytoplasmic protein that is found in neurons and somatic cells. In patients with Huntington's disease (HD), the NH2-terminal region of huntingtin has an expanded polyglutamine tract. An abnormal protein interaction by mutant huntingtin has been proposed as a mechanism for HD pathogenesis. Huntingtin associates with vesicle membranes and interacts with proteins involved in vesicle trafficking. It is unclear where along vesicle transport pathways wild-type and mutant huntingtins are found and whether polyglutamine expansion affects this localization. To distinguish wild-type and mutant huntingtin, fibroblasts from normals and HD patients with two mutant alleles (homozygotes) were examined. Immunofluorescence confocal microscopy showed that mutant huntingtin localized with clathrin in membranes of the trans Golgi network and in clathrin-coated and noncoated endosomal vesicles in the cytoplasm and along plasma membranes. Separation of organelles in Nycodenz gradients showed that in normal and HD homozygote patient cells, huntingtin was present in membrane fractions enriched in clathrin. Similar results were obtained in fibroblasts from heterozyote juvenile HD patients who had a highly expanded polyglutamine tract in the HD allele. Western blot analysis of membrane fractions from rat brain showed that wild-type huntingtin was present in fractions that contained purified clathrin-coated membranes or a mixture of clathrin-coated and noncoated membranes. Electron microscopy of huntingtin immunoreactivity in rat brain revealed labeling along dendritic plasma membranes in association with clathrin-coated pits and clusters of noncoated endosomal vesicles 40-60 nm in diameter. These data suggest that wild-type and mutant huntingtin can influence vesicle transport in the secretory and endocytic pathways through associations with clathrin-coated vesicles.

Quantitation of hepatitis C virus RNA in liver transplant recipients

BACKGROUND/AIMS

Hepatitis C virus (HCV) infection is common in liver transplant recipients, yet the effects of immunosuppression on HCV RNA levels and the relationship of HCV RNA levels to hepatic damage have not been studied.

METHODS

To explore these issues, we measured HCV RNA in serum by polymerase chain reaction amplification and branched DNA assay from 100 HCV-infected patients undergoing liver transplantation.

RESULTS

Mean posttransplant levels were 16-fold higher than pretransplant values (7,935,000 and 496,000 Eq/mL, respectively; n = 65; P < 0.0001). Patients with high pretransplant levels had higher mean posttransplant levels than those with low pretransplant levels (17,119,000 and 6,504,000 Eq/mL, respectively; P = 0.064). Posttransplant levels were similar in patients with recurrent and acquired infection and were independent of time of sampling. Fifty percent of patients with HCV infection had normal liver biopsy specimens, and there was no strong relationship between level of viremia and degree of hepatic damage.

CONCLUSIONS

HCV RNA levels increase markedly following liver transplantation. The frequent finding of viremia in the absence of histological hepatitis suggests that a "carrier state" is common. Absence of allograft damage in some (despite high levels of viral RNA) suggests that in immunosuppressed patients, HCV infection may be tolerated without direct hepatic damage.

"Occult" hepatitis B virus as source of infection in liver transplant recipients

Hepatitis B virus (HBV) infection almost always recurs after liver transplantation in patients who were surface antigen (HBsAg) positive before surgery but apparent de novo acquisition of infection in a transplant setting has not previously been reported. We have used sensitive techniques to elucidate the origin of such infections in patients in a California transplantation programme. We tested post-transplant serum from 207 patients who had been HBsAg negative and found 20 to be HBsAg positive. The origin of infection was identified in 7 patients, being occult pre-transplant infection in 5 and occult infection in the donor in 2. No pre-transplant patient nor donor with demonstrable HBV DNA had serological markers of hepatitis B. Post-transplant HBV DNA was present in serum from 19 patients. Analysis of the variable pre-S region of HBV demonstrated 100% sequence homology between recipient liver and post-transplant serum (2 patients) and between donor serum and recipient post-transplant serum (2). There was only 84% homology between the 2 different patients infected with subtype adw. 19 patients are alive, 9 without histological evidence of hepatitis (mean follow-up 33 months), and survival was significantly greater than that of a group with recurrent HBV infection. Apparent acquisition of HBV infection with liver transplantation is not rare, and may be due to occult pre-transplant infection or occult infection in the donor. The post-transplant outcome of this infection tends to be benign but our findings do underscore the clinical relevance of HBV infection in the absence of serological markers.

Developmental changes due to long-distance movement of a homeobox fusion transcript in tomato

Long-distance movement of RNA through the phloem is known to occur, but the functional importance of these transported RNAs has remained unclear. Grafting experiments with a naturally occurring dominant gain-of-function leaf mutation in tomato were used to demonstrate long-distance movement of mutant messenger RNA (mRNA) into wild-type scions. The stock-specific pattern of mRNA expression was graft transmissible, indicating that the mRNA accumulation pattern is inherent to the transcript and not attributable to the promoter. The translocated mRNA caused changes in leaf morphology of the wild-type scions, suggesting that the translocated RNA is functional.

Incidence of gastroenteropancreatic neuroendocrine tumours: a systematic review of the literature

Based on the current medical literature, the worldwide incidence of neuroendocrine tumours (NETs) seems to have increased; however, a systematic literature overview is lacking. This study aimed to collect all available data on the incidence of gastroenteropancreatic (GEP)-NETs and characteristics of population to establish their epidemiology. A sensitive MEDLINE search was carried out. The papers were selected via a cascade process that restricted the initial pool of 7991 articles to 33, using predefined inclusion and exclusion criteria. Original articles evaluating the incidence of sporadic GEP-NETs in regional, institutional and national registries were considered. The majority of data originated from the US National Cancer Institute Surveillance, Epidemiology and End Results database and from national cancer registries in Western Europe. Generally, because of the retrospective nature of existing databases the outcomes of studies might be biased, which hinders the drawing of firm conclusions. The age-adjusted incidence of GEP-NETs has increased steadily over the past four decades (1973-2007), increasing 3.65-fold in the USA and 3.8- to 4.8-fold in the UK. Incidence has changed variably from one anatomical site to another. The greatest increase in incidence occurred for gastric and rectal NETs, while the smallest increase occurred for small intestine NETs. There were gender and racial differences, which differed site by site and, in some cases, changed over time. The incidence rates (IRs) of GEP-NETs have increased significantly in the last 40 years. Data are only available from North America, Western Europe and Japan. A site-by-site analysis revealed that the IRs of some NETs increased more than those of others.

A novel antimicrobial peptide from Bufo bufo gargarizans

A potent and structurally novel antimicrobial peptide was isolated and characterized from the stomach tissue of Bufo bufo gargarizans, an Asian toad. The 39-amino acid peptide, named buforin I, was purified to homogeneity by heparin-affinity column and reverse-phase HPLC. The amino acid sequence of buforin I was identical in 37 of 39 amino-terminal residues of Xenopus histone H2A. The buforin I showed strong antimicrobial activities in vitro against a broad-spectrum of microorganisms and was found to be more potent than magainin 2. In addition, a 21-amino acid peptide, named buforin II, which was derived from buforin I, showed more potent antimicrobial activities than buforin I.

Classification and definition of major flares in SLE clinical trials

Multiple reliable and valid disease activities indices exist and have been used successfully in longitudinal studies. However, the definition of flare, using these intruments, has not been universally decided or accepted. Because flare is one of the three major patterns of lupus activity, it will remain an important outcome measure in both longitudinal and clinical trial studies.

Nitric oxide negatively regulates c-Jun N-terminal kinase/stress-activated protein kinase by means of S-nitrosylation

NO, produced from l-arginine in a reaction catalyzed by NO synthase, is an endogenous free radical with multiple functions in mammalian cells. Here, we demonstrate that endogenously produced NO can suppress c-Jun N-terminal kinase (JNK) activation in intact cells. Treatment of BV-2 murine microglial cells with IFN-gamma induced endogenous NO production, concomitantly suppressing JNK1 activation. Similarly, IFN-gamma induced suppression of JNK1 activation in RAW264.7 murine macrophage cells and rat alveolar macrophages. The IFN-gamma-induced suppression of JNK1 activation in BV-2, RAW264.7, or rat alveolar macrophage cells was completely prevented by N(G)-nitro-l-arginine, a NO synthase inhibitor. Interestingly, the IFN-gamma-induced suppression of JNK1 activation was not affected by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of guanylyl cyclase. 8-Bromo-cGMP, a membrane-permeant analogue of cGMP, did not change JNK1 activation in intact cells either. In contrast, S-nitro-N-acetyl-dl-penicillamine (SNAP), a NO donor, inhibited JNK1 activity in vitro. Furthermore, a thiol reducing agent, DTT, reversed not only the in vitro inhibition of JNK1 activity by SNAP but also the in vivo suppression of JNK1 activity by IFN-gamma. Substitution of serine for cysteine-116 in JNK1 abolished the inhibitory effect of IFN-gamma or SNAP on JNK1 activity in vivo or in vitro, respectively. Moreover, IFN-gamma enhanced endogenous S-nitrosylation of JNK1 in RAW264.7 cells. Collectively, our data suggest that endogenous NO mediates the IFN-gamma-induced suppression of JNK1 activation in macrophage cells by means of a thiol-redox mechanism.

Controlling Chemical Turbulence by Global Delayed Feedback: Pattern Formation in Catalytic CO Oxidation on Pt(110)

Control of spatiotemporal chaos is one of the central problems of nonlinear dynamics. We report on suppression of chemical turbulence by global delayed feedback using, as an example, catalytic carbon monoxide oxidation on a platinum (110) single-crystal surface and carbon monoxide partial pressure as the controlled feedback variable. When feedback intensity was increased, spiral-wave turbulence was transformed into new intermittent chaotic regimes with cascades of reproducing and annihilating local structures on the background of uniform oscillations. The global feedback further led to the development of cluster patterns and standing waves and to the stabilization of uniform oscillations. These findings are reproduced by theoretical simulations.