ATP-induced dormant pulmonary veins originating from the carina region after circumferential pulmonary vein isolation of atrial fibrillation

INTRODUCTION

Elimination of transient pulmonary vein recurrences (dormant PVs) induced by an ATP injection and ablation at the PV carina region is an effective strategy for atrial fibrillation (AF) ablation. The relationship between dormant PVs and the PV carina region has not been evaluated.

METHODS

A total of 212 consecutive symptomatic AF patients underwent circumferential PV electrical isolation (CPVEI) with a double lasso technique. They were divided into 2 groups in a retrospective review; Group 1: those given an ATP injection during an intravenous isoproterenol infusion after the CPVEI (n = 106), and Group 2: those in which it was not given after the CPVEI (n = 106). Radiofrequency energy was applied at the earliest dormant PV activation site identified using a Lasso catheter on the CPVEI line and then PV carina region if it was ineffective.

RESULTS

After a successful PVEI, 54 patients (51%) in Group 1 had PV reconnections during an ATP injection. Acute PVEI sites were observed on the carina region within the CPVEI line in the right PVs (16%) and left PVs (10%). Dormant PVs were reisolated at the carina region in the right PVs (23%) and left PVs (26%). The distribution of the dormant PV sites, except for the RIPV, significantly differed from that of the acute PVEI sites (P < 0.05). Further, AF recurred significantly in the Group 2 patients as compared to those in Group 1 during 16 +/- 6.1 months of follow-up (P < 0.05).

CONCLUSION

PV carina region origins may partly be responsible for an acute PVEI and potential recurrences.

Kinetics of the accumulation of jasmonic acid and its derivatives in systemic leaves of tobacco (Nicotiana tabacum cv. Xanthi nc) and translocation of deuterium-labeled jasmonic acid from the wounding site to the systemic site

In plants, the mobile signal needed for wound-induced systemic acquired resistance (WSR) has been elusive. The signal compound involved in WSR is supposed to be JA or its derivatives. On the basis of kinetic study of the accumulation of JA or its derivatives, it was discovered that JA, JA-Ile, tuberonic acid (TA, 12-OH epi-JA), and tuberonic acid glucoside (TAG) accumulated in systemic tissues in response to mechanical wounding stress in the tobacco plant (Nicotiana tabacum). Attempts to recover deuterium-labeled JA in systemic leaves after feeding the wounded leaves with deuterium-labeled JA were successfully done. It was also found that the translocated deuterium-labeled JA was metabolized to TA in systemic leaves under feeding of deuterium-labeled JA to the wounding leaves.

Estimation of the absorption coefficients of two-layered media by a simple method using spatially and time-resolved reflectances

Our newly developed method using spatially and time-resolved reflectances can easily estimate the absorption coefficients of each layer in a two-layered medium if the thickness of the upper layer and the reduced scattering coefficients of the two layers are known a priori. We experimentally validated this method using phantoms and examined its possibility of estimating the absorption coefficients of the tissues in human heads. In the case of a homogeneous plastic phantom (polyacetal block), the absorption coefficient estimated by our method agreed well with that obtained by a conventional method. Also, in the case of two-layered phantoms, our method successfully estimated the absorption coefficients of the two layers. Furthermore, the absorption coefficients of the extracerebral and cerebral tissue inside human foreheads were estimated under the assumption that the human heads were two-layered media. It was found that the absorption coefficients of the cerebral tissues were larger than those of the extracerebral tissues.

A mechanism for low penetrance in an ALS family with a novel SOD1 deletion

BACKGROUND

About 20% of familial amyotrophic lateral sclerosis (ALS) is caused by mutations in SOD1 and is typically transmitted as an autosomal dominant trait. However, due to reduced mutation penetrance, the disease may present in a recessive or sporadic manner.

OBJECTIVE

To determine the factors responsible for the low penetrance of the SOD1 mutation.

METHODS

Twelve members of a Canadian ALS family of Filipino origin were recruited for the study. SOD1 was sequenced in the proband. SOD1 expression was assessed by real-time-PCR and immunoblotting.

RESULTS

The proband was a homozygous carrier of a novel 6 bp deletion in exon 2 (DeltaG27/P28), the pathologic significance of which was confirmed by immunohistochemistry. Eight living family members are heterozygotes and remain unaffected at ages ranging between 48 and 85 years. Haplotype analysis showed that the deletion is a single founder mutation likely common in the Cagayan province (Philippines). The low penetrance of the mutation is explained by the fact that it enhances the naturally occurring alternative splicing of exon 2 of the SOD1 mRNA, leading to reduced transcription of the mutant allele. Indeed, Western blot analysis demonstrated the low level of SOD1 protein in carriers of the DeltaG27/P28 compared to wild-type individuals or a carrier of the A4V SOD1 mutation.

CONCLUSION

The enhanced splicing of exon 2 acts as a natural knock-down of the mutant SOD1 allele in the Filipino amyotrophic lateral sclerosis (ALS) family. There is a need for careful investigation of splicing isoforms of SOD1 and other ALS genes as factors influencing the severity of disease.

Quantitative analysis and characteristics of the electrograms recorded within the non-coronary aortic sinus of Valsalva

BACKGROUND

Some supraventricular tachycardias could be ablated from the non-coronary sinus of Valsalva (NSV). However, the characteristics of the NSV electrograms have not been clarified.

METHODS AND RESULTS

A quantitative analysis of the NSV electrograms was performed in 5 patients with tachycardias arising from near the atrioventricular node (AVN) and the His-bundle region, and in 20 control subjects. In another 7 control subjects, the NSV electrograms were compared with those recorded at the left and right sinus of Valsalva (LSV and RSV). The NSV electrograms during sinus rhythm had a larger atrial amplitude than ventricular amplitude, and the ratio of the atrial amplitude to the ventricular amplitude was usually >1, which was apparently different from the LSV and RSV electrograms. A tiny but distinct His-bundle deflection was sometimes recorded at the NSV during sinus rhythm while it was not during the tachycardia. The distance to the His-bundle region in the anteroseptal right atrium was shorter from the NSV than from the RSV or LSV.

CONCLUSIONS

The precise identification of the catheter position at the NSV is possible using the characteristics of the electrograms. Much attention should be paid during ablation to the NSV because of its vicinity to the AVN and His-bundle region.

Heterogeneity within a large kindred with frontotemporal dementia: a novel progranulin mutation

BACKGROUND

Frontotemporal dementia (FTD) in several 17q21-linked families was recently explained by truncating mutations in the progranulin gene (GRN).

OBJECTIVE

To determine the frequency of GRN mutations in a cohort of Caucasian patients with FTD without mutations in known FTD genes.

METHODS

GRN was sequenced in a series of 78 independent FTD patients including 23 familial subjects. A different Calabrian dataset (109 normal control subjects and 96 FTD patients) was used to establish the frequency of the GRN mutation.

RESULTS

A novel truncating GRN mutation (c.1145insA) was detected in a proband of an extended consanguineous Calabrian kindred. Segregation analysis of 70 family members revealed 19 heterozygous mutation carriers including 9 patients affected by FTD. The absence of homozygous carriers in a highly consanguineous kindred may indicate that the loss of both GRN alleles might lead to embryonic lethality. An extremely variable age at onset in the mutation carriers (more than five decades apart) is not explained by APOE genotypes or the H1/H2 MAPT haplotypes. Intriguingly, the mutation was excluded in four FTD patients belonging to branches with an autosomal dominant mode of inheritance of FTD, suggesting that another novel FTD gene accounts for the disease in the phenocopies. It is difficult to clinically distinguish phenocopies from GRN mutation carriers, except that language in mutation carriers was more severely compromised.

CONCLUSION

The current results imply further genetic heterogeneity of frontotemporal dementia, as we detected only one GRN-linked family (about 1%). The value of discovering large kindred includes the possibility of a longitudinal study of GRN mutation carriers.

Subcutaneous administration of lactone form of simvastatin stimulates ectopic osteoinduction by rhBMP-2

OBJECTIVE

To evaluate the effects of various 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) on ectopic osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2) using different administration methods.

MATERIALS AND METHODS

Disks containing 5 mug of rhBMP-2 and type I collagen were implanted into the calf muscles of 6-week-old male rats (n = 64). Either the lactone form of simvastatin (SV), open hydroxy-acid form of simvastatin (SVA), cerivastatin (CVA), or vehicle (control) was then administered per orally (PO group) or subcutaneously (SC group) for 20 days. The disks were removed on day 21 after implantation, and ectopic induced bone formation was evaluated by radiographic, histologic, and biochemical analysis.

RESULTS

Both the projected and radiopaque area on X-ray film, and the calcium content of the SV group in the SC group (SV-SC group) were significantly greater than those in the other SC and PO groups. Alkaline phosphatase activity and tartrate-resistant acid phosphatase activity in the SV-SC group were significantly lower than those in the other SC and PO groups. Histologic examination revealed an increase of ectopic induced bone volume in the SV-SC group.

CONCLUSION

Subcutaneous administration of SV stimulates ectopic osteoinduction by rhBMP-2 through reduction of bone turnover.

Cabergoline scavenges peroxynitrite enhanced by l-DOPA therapy in patients with Parkinson's disease

Long-term or high-dose L-DOPA therapy in patients with Parkinson's disease (PD) may accelerate degeneration of dopaminergic neurons, possibly by increasing oxidative stress. To investigate the effects of cabergoline on peroxynitrite-mediated oxidative damage caused by L-DOPA, the concentration of 3-nitrotyrosine in cerebrospinal fluid (CSF) of 18 PD patients was compared with that in 20 normal controls. The concentration of 3-nitrotyrosine in patients following L-DOPA therapy was significantly higher than in untreated PD patients and controls. On the other hand, the concentration in PD patients after cabergoline therapy was significantly lower than in PD patients after L-DOPA therapy alone. These data suggest that cabergoline scavenges peroxynitrite induced by L-DOPA in patients with PD.

LRRK2 gene in Parkinson disease: mutation analysis and case control association study

BACKGROUND

In addition to the four well-confirmed genes linked to early-onset Parkinson disease (PD) (SNCA, PARKIN, DJ-1, and PINK1), mutations in the leucine-rich repeat kinase 2 gene (LRRK2) have recently been identified in families with autosomal dominant late-onset PD.

OBJECTIVE

To perform mutation analysis of LRRK2 in probands of families showing dominant inheritance of PD and to conduct a case control association study to test the hypothesis that common coding variations might be associated with increased susceptibility to PD.

METHODS

All 51 LRRK2 coding exons were sequenced in 23 probands and the mutation frequencies were evaluated in 180 neurologically normal control subjects. For the association study the authors genotyped four coding LRRK2 polymorphisms in 250 normal control subjects and 121 patients with PD (predominantly white patients of Canadian origin), 84% of whom had age at onset before 50 years and 42% had a positive family history.

RESULTS

The authors identified three probands with heterozygous LRRK2 mutations: two of them have the known G2019S substitution and one proband has a novel I1371V substitution. Mutation analysis of a large family demonstrated complete segregation of the G2019S with PD. However, there was no association between PD and any of the four polymorphisms at the allelic or genotypic levels (p > 0.17). Furthermore, the authors did not detect a modifying effect for any genotype or of APOE genotypes upon the age at onset in the PD group (p > 0.20).

CONCLUSIONS

The results support the prior suggestion that LRRK2 mutations cause PD. The disease in the families reported here presents a phenotype indistinguishable from typical PD. All three families demonstrate a very variable age at onset that is not explained by APOE genotypes. The common coding variations in the LRRK2 gene neither constitute strong PD risk factors nor modify the age at onset; however, the possibility of a modest risk effect remains to be assessed in large datasets.

Characteristic sequence changes of hepatitis C virus genotype 2b associated with sustained biochemical response to IFN therapy

In hepatitis C virus (HCV) genotype 2b infection, viral eradication (sustained viral response; sVR) is obtained in about 40% by interferon monotherapy, whereas a considerable proportion of non-sVR patients exhibit sustained biochemical response (sBR) showing normal biochemical values despite persistent viraemia. However, the mechanism of sBR has not yet been established. In this study, we analysed serial changes in full-length sequences of HCV genotype 2b before and after interferon (IFN) therapy in five patients with sBR and five with no response (NR; persistent viraemia and abnormal biochemical values after IFN therapy). The overall substitution rate of amino acids in the full-length HCV genome was higher in the sBR group than in the NR group [2.22 +/- 0.48 (10(-3) changes/site/year) vs 1.04 +/- 0.30: P = 0.002]. When the genetic changes were analysed for individual HCV proteins, the sBR group had significantly higher substitution rates of amino acid in NS4A [8.82 +/- 2.80 (10(-3) changes/site/year) vs 0: P = 0.001]. These amino acid changes in sBR were mainly located in the binding motifs of HLA class I molecules including those frequently found in the Japanese population. These results demonstrated that the greater amino acid changes of HCV arising during interferon therapy are associated with the establishment of sBR. Although functional significance of these changes awaits further investigation, the finding that amino acid changes in NS4A in sBR patients are mainly located in the HLA class I binding motifs illustrated the potential roles of the escape mutations of HCV genome from CTLs in the decreasing activities of hepatitis in sBR.

Specificity of human trans-sialidase as probed with gangliosides

It has been shown that human blood contains a soluble 67 kDa enzyme, belonging by its donor-acceptor properties to trans-sialidases. The enzyme is capable of both cleaving and synthesizing alpha2-3 and alpha2-6 sialosides [Atherosclerosis2001, 159, 103]. In this work the study of donor-acceptor specificity of the new enzyme was extended. It has been demonstrated in vitro that trans-sialidase possesses the ability of transferring Neu5Ac residue to acceptor (asialofetuin) both from alpha2-3- (GM1, GM3, GD1a), and alpha2-8-sialylated gangliosides (GD3 and GD1b, but not GT1b and GQ1b). Transfer of radiolabeled Neu5Ac from fetuin to glycosphingolipids demonstrated that Lac-Cer>mono- and disialogangliosides>GT1b>GQ1b were acceptors for this enzyme. Two methods were used to reveal whether alpha2-8 bond can be formed between Neu5Ac residues during trans-sialylation, that is immunochemical detection using monoclonal antibodies specific to alpha2-8 di- and oligosialic acids, and fluorometric C7/C9 analysis. Both methods demonstrated the formation of Neu5Acalpha2-8Neu5Ac termination by trans-sialidase, for example, in case of the use 3'SL as sialic acid donor and Neu5Ac-PAA or LDL as acceptor. Thus, human trans-sialidase in vitro displays wide substrate specificity: the enzyme is capable of digesting as well as synthesizing alpha2-3, alpha2-6, and alpha2-8 sialosides.

Introduction of NS5A mutations enables subgenomic HCV replicon derived from chimpanzee-infectious HC-J4 isolate to replicate efficiently in Huh-7 cells

Hepatitis C virus (HCV) subgenomic replicon has been reported to replicate efficiently and continuously in human hepatoma Huh-7 cells. To extend the previous results to other isolated HCV clones, we constructed another HCV replicon from HC-J4, one of chimpanzee-infectious HCV clones. An HCV replicon derived from HC-J4 (RpJ4) consists of HCV-5' untranslated region, neomycin phosphotransferase gene, the encephalomyocarditis virus internal ribosomal entry site, HCV nonstructural region, NS3 to NS5B, and HCV-3' untranslated region. The adaptive mutations known to be required for HCV-Con1 replicon were introduced in RpJ4 replicon, aa.(amino acids number according to HC-J4) 2197 serine to proline, deletion of serine at aa.2201, and aa.2204 serine to isoleucine (RpJ4-S2197P, RpJ4-S22001del, and RpJ4-S2204I). RpJ4/ISDR mutant and RpJ4-S2201del/ISDR mutant were also constructed by introducing six amino acid mutations into the interferon sensitivity determining region (ISDR). After transfection into Huh-7 cells and G418 selection, RpJ4 and RpJ4/ISDR mutants did not produce any colony. In contrast, G418-resistant cells were transduced efficiently by RpJ4-S2197P, RpJ4-S2204I, RpJ4-S2201del and RpJ4-S2201del/ISDR mutant, with the RpJ4-S2201del/ISDR mutant being most efficient. Hence the HCV replicon derived from HC-J4 can replicate efficiently following the introduction of adaptive mutations into the upstream region of ISDR. Moreover, additional introduction of mutations into ISDR further enhanced its replication. These findings demonstrate that the genetic structure of the NS5A domain is critical in HCV replications.

Role of Arginine Residues on the S4 Segment of the Bacillus halodurans Na+ Channel in Voltage-sensing

The one-domain voltage-gated sodium channel of Bacillus halodurans (NaChBac) is composed of six transmembrane segments (S1-S6) comprising a pore-forming region flanked by segments S5 and S6 and a voltage-sensing element composed of segment S4. To investigate the role of the S4 segment in NaChBac channel activation, we used the cysteine mutagenesis approach where the positive charges of single and multiple arginine (R) residues of the S4 segment were replaced by the neutrally charged amino acid cysteine (C). To determine whether it was the arginine residue itself or its positive charge that was involved in channel activation, arginine to lysine (R to K) mutations were constructed. Wild-type (WT) and mutant NaChBac channels were expressed in tsA201 cells and Na+ currents were recorded using the whole-cell configuration of the patch-clamp technique. The current/voltage (I-V) and conductance/voltage (G-V) relationships steady-state inactivation (h(infinity)) and recovery from inactivation were evaluated to determine the effects of the S4 mutations on the biophysical properties of the NaChBac channel. R to C on the S4 segment resulted in a slowing of both activation and inactivation kinetics. Charge neutralization of arginine residues mostly resulted in a shift toward more positive potentials of G-V and h(infinity) curves. The G-V curve shifts were associated with a decrease in slope, which may reflect a decrease in the gating charge involved in channel activation. Single neutralization of R114, R117, or R120 by C resulted in a very slow recovery from inactivation. Double neutralization of R111 and R129 confirmed the role of R111 in activation and suggested that R129 is most probably not part of the voltage sensor. Most of the R to K mutants retained WT-like current kinetics but exhibited an intermediate G-V curve, a steady-state inactivation shifted to more hyperpolarized potentials, and intermediate time constants of recovery from inactivation. This indicates that R, at several positions, plays an important role in channel activation. The data are consistent with the notion that the S4 is most probably the voltage sensor of the NaChBac channel and that both positive charges and the nature of the arginine residues are essential for channel activation.

Differential gene-expression profiles associated with gastric adenoma

Gastric adenomas may eventually progress to adenocarcinomas at varying rates. The purpose of the present study was to identify gene-expression profiles linked to the heterogeneous nature of gastric adenoma as compared to adenocarcinoma. Suppression subtractive hybridisation analysis was performed to extract relevant genes from two cases of low- and high-grade gastric adenomas. The identified genes were quantified by RT-PCR in 14 low-grade adenoma, nine high-grade adenoma and nine adenocarcinoma samples, followed by hierarchical clustering analysis to separate tumours into groups according to their gene-expression profiles. Nine genes previously implicated in carcinogenesis in a variety of organs, including three genes related to gastric adenocarcinoma, were identified. The overexpression of these genes in gastric adenoma has not been reported previously. The clustering analysis of these nine genes across 32 cases identified three groups, one of which consisted primarily of adenocarcinomas, whereas the other two groups consisted of adenomas. One group of adenomas, characterised by larger tumour size, exhibited gene-expression profiles of an intestinal cell lineage implicated in the pathogenesis of an intestinal-type gastric adenocarcinoma. Another adenoma group consisting of low-grade adenomas with smaller tumour size exhibited a unique expression profile. In conclusion, clustering analysis of expression profiles using a limited number of genes may serve as molecular markers for gastric adenoma with different biological properties. Although the prognostic values of these gene-expression profiles need to be evaluated in further follow-up study of adenoma cases, these findings add new insights to (a) our understanding of the pathogenesis of gastric tumours, (b) the development of specific tumour markers for clinical practice, and (c) the design of novel therapeutic targets.

Distribution of estrogen, nonylphenol and its derivatives in the sediments of a shallow lake

To determine the distribution of endocrine disruptors (EDs) in lake water and sediments, field investigation was conducted in Lake Teganuma, which is a shallow eutrophic lake, highly affected by human activities. Concentration profiles with sediment depths were obtained for estrogens, nonylphenol (NP), nonylphenol ethoxylates (NPnEO), and nonylphenoxy acetic acids (NPnEC). 17beta-Estradiol (E2) was rarely detected, and 17alpha-ethynylestradiol (EE2) and estriol (E3) were undetected at all depths (0-98 cm) in any of the sediment core samples. The sediment concentrations of estrone (E1) ranging from <0.05 to 3.5 microg/kg-dry wt. and NP from 11.8 microg/kg-dry wt. to 21 mg/kg-dry wt. were obtained. The maximum concentrations of NPnEO and NPnEC in the core sediments were 2.5 mg/kg-dry wt. and 1.4 mg/kg-dry wt., respectively. The EDs concentrations are higher at the inlet than at the outlet (except for NP) in the sediments near the surface. The longitudinal distributions of E1, NPnEO and NPnEC in the benthic sediments show that the concentrations are highest at the inlet, and are fairly constant at lower levels towards the downstream. The obtained results also indicate that NP tends to be adsorbed to the organic particulates produced by algae, followed by sedimentation near the outlet of the lake.