Quantitative fiber tracking of the optic radiation is correlated with visual-evoked potential amplitude in preterm infants

BACKGROUND AND PURPOSE

Children born preterm are at risk for adverse outcome, including visual impairment. We examined the relationship between neonatal DTI and sVEP in children born preterm to determine whether visual outcomes are related to early measurements of brain microstructure.

MATERIALS AND METHODS

Subjects were born at <34 weeks gestation and imaged before term-equivalent age. DTI fiber tracking was used to delineate the optic radiations and measure tract-specific average FA, D(av), and parallel and transverse diffusivity. Visual-evoked response amplitudes were measured as a function of spatial frequency, contrast, and vernier offset size with sVEP at 6-20 months after birth. The association between DTI and sVEP was assessed by using the Spearman correlation coefficient and linear regression for repeated measures.

RESULTS

Nine children with 15 scans were included. The peak response amplitudes for spatial frequency sweeps were associated with increasing FA and decreasing D(av) and transverse diffusivity (P ≤ .006) but not with parallel diffusivity (P = 1). There was only modest association with the swept contrast condition and no detectable association with the vernier offset sweeps.

CONCLUSIONS

Microstructure of the optic radiations measured shortly after birth is associated with quantitatively measured responses elicited by moderate-to-high contrast spatiotemporal gratings in infancy. These findings are in keeping with studies showing a relationship between brain microstructure and function. While the clinical impact is not known, quantitative neuroimaging of white matter may ultimately be important for predicting outcome in preterm neonates.

Spatio-temporal tuning of coherent motion evoked responses in 4-6 month old infants and adults

Motion cues provide a rich source of information about translations of the observer through the environment as well as the movements of objects and surfaces. While the direction of motion can be extracted locally these local measurements are, in general, insufficient for determining object and surface motions. To study the development of local and global motion processing mechanisms, we recorded Visual Evoked Potentials (VEPs) in response to dynamic random dot displays that alternated between coherent rotational motion and random motion at 0.8 Hz. We compared the spatio-temporal tuning of the evoked response in 4-6 months old infants to that of adults by recording over a range of dot displacements and temporal update rates. Responses recorded at the frequency of the coherent motion modulation were tuned for displacement at the occipital midline in both adults in infants. Responses at lateral electrodes were tuned for speed in adults, but not in infants. Infant responses were maximal at a larger range of spatial displacement than that of adults. In contrast, responses recorded at the dot-update rate showed a more similar parametric displacement tuning and scalp topography in infants and adults. Taken together, our results suggest that while local motion processing is relatively mature at 4-6 months, global integration mechanisms exhibit significant immaturities at this age.

Expression of Reversion-inducing Cysteine-rich Protein with Kazal Motifs in Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus: Links to Disease Activity, Damage Accrual and Matrix Metalloproteinase 9 Secretion

We studied the expression of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) on peripheral blood mononuclear cells (PBMCs), the serum concentration of matrix metalloproteinase 9 (MMP-9) and the MMP-9 secretion ability of PBMCs in patients with systemic lupus erythematosus (SLE), and clinical features were assessed. Compared with PBMCs from healthy donors, PBMCs from SLE patients expressed less RECK protein and mRNA but secreted more MMP-9. The serum concentration of MMP-9 was, however, lower in SLE patients than in healthy donors. The level of RECK protein was inversely associated with the Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI) and MMP-9 secretion in SLE, but no relationship was found between serum MMP-9 concentration and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). In conclusion, the level of RECK protein expressed in PBMCs could be used to predict organ or system damage in SLE and this might help in developing new therapies for SLE targeted at MMP-9.

Islet autoantibodies are associated with HLA-DQ genotypes in Han Chinese patients with type 1 diabetes and their relatives

The objective of this study was to explore the relationship between islet autoantibodies of glutamic acid decarboxylase (GADA), islet antigen-2A (IA-2A), insulin autoantibody (IAA), and human leukocyte antigen (HLA)-DQ genotypes in type 1 diabetes (T1D) patients and their first-degree relatives (FDRs). Cross-sectional and case-control study. Four hundred and ninety-five T1D patients, 419 FDRs, and 376 control subjects in Han Chinese populations were recruited and tested for GADA and IA-2A, while 71 cases, all FDRs and 300 controls were tested for IAA. The 338 T1D patients (including 187 antibody-positive and 151 antibody-negative patients), 173 FDRs and 278 controls were genotyped for HLA-DQ with polymerase chain reaction sequencing-based method. Compared with the control, the frequency of DQA1*03-DQB1*0303, DQA1*05-DQB1*0201, and DQA1*03-DQB1*0401 haplotypes was higher (P < 0.05-0.01) but DQA1*0102-DQB1*0602 haplotype was lower (P < 0.01) in T1D patients. DQA1*03 allele was less in the FDRs than in their probands (P < 0.05). GADA was more prevalent in T1D patients carrying DQA1*05-DQB1*0201 or DQA1*03-DQB1*0401 haplotype (55.8% vs 41.0%, 65.5% vs 40.3%, P < 0.05-0.01), whereas IA-2A presented more in the patients carrying DQA1*03-DQB1*0303 haplotype (27.0% vs 7.9%, P < 0.05-0.01), both GADA and IA-2A showed frequently in the patients with DQA1*03-DQB1*0303/DQA1*05-DQB1*0201 haplotypes (34.5% vs 9.7%, P < 0.01). GADA positivity was lower in the patients with DQA1*0102-DQB1*0602 haplotype (16.7% vs 45.9%, P < 0.05). The frequency of IAA was not different between patients with and without susceptible DQ haplotypes (P > 0.05). GADA, IA-2A or IAA presented frequently in FDRs with DQA1*03-DQB1*0303 haplotype. The findings in the study indicate that some of specific HLA-DQA1/-DQB1 genotypes and haplotypes not only confer susceptibility to T1D but also are associated with the presence of the islet autoantibodies in the Han Chinese population.

Comparison of Bacillus monooxygenase genes for unique fatty acid production

This paper reviews Bacillus genes encoding monooxygenase enzymes producing unique fatty acid metabolites. Specifically, it examines standard monooxygenase electron transfer schemes and related domain structures of these fused domain enzymes on route to understanding the observed oxygenase activities. A few crystallographic analyses of the standard bearer enzyme P450(BM-3) are discussed to try to rationalize the common chemistries of this important enzyme family. Detailed P450(BM-3) enzyme activities toward different substrates and the unique substrate-specific primary oxidation products are examined. A few orthologs to the recurring P450(BM-3) enzyme as well as related small single-to-triple nucleotides changed mutants are also discussed. Finally, preliminary data characterizing unique in vivo-based primary and secondary products of a novel ortholog, the ALA2 strain, are presented. This later strain synthesizes several unique multi-oxidized reaction products that require additional study to further understand. It is hoped that a better understanding of these oxygenase reactions, particularly the ALA2 strain, will allow for realistically priced production of target multiple-oxygenated compounds with potential uses as specialty chemicals or as therapeutic agents.

Identification of genomic DNA signatures predicting relapse in low- and intermediate-risk neuroblastoma using a case control design and high-density SNP genotyping: A Children's Oncology Group (COG) study

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Background: Neuroblastoma (NB) is a childhood malignancy with a heterogeneous clinical course. Clinical and genomic markers are powerful predictors of outcome and are used to stratify cases for treatment intensity, but imprecision remains. Methods: We identified all disease recurrences from the recently closed COG low- (P9641: 903 eligible, 63 events) and intermediate-risk (A3961: 467 eligible, 40 events) NB phase III trials. To date, tumor DNA from 35 cases and 90 controls (P9641/A3961 patients without event) was used for whole genome copy number and genotype evaluation on the Illumina HumanHap550 (550K SNPs) array. An in-house algorithm was developed to assign genomic copy number and loss of heterozygosity based on probe intensity (log R ratio) and degree of allelic imbalance (B allele frequency). Results: A total of 988 chromosomal aberrations were identified; 231 (23.4%) were whole chromosome (WC) copy number aberrations (CNA). Unsupervised hierarchical clustering identified 10 tumor subsets, with 2 highly enriched with cases showing progression events (13/21; 61%), and 2 dominated by WC gains (chromosomes 2, 6, 7 and 18) with only 2/20 events. Regional aberrations most highly associated with EFS included loss of 11q14-qter (p=0.036), and gain of 11p (p=0.003), 11q13 (p=0.020), and 17q23-qter (p=0.005). Other regional CNAs at borderline univariate significance for EFS included partial gain at 2p, 2q, 6q, 7q, 12q and 13q. The pattern 11p and proximal 11q gain associated with loss of distal 11q was associated with relapse and death (p=0.006 and p=0.023). Conclusion: Whole genome SNP genotyping detects patterns of chromosomal CNAs predictive of EFS, even in situations where events are rare such as low- and intermediate- risk NB. These data support chromosomal 11 and 17 structural CNAs as being most highly predictive of relapse in otherwise favorable NBs, but also suggest that other CNAs likely cooperate and may improve precisions for risk prediction. These data can be used to identify patients eligible for chemotherapy reduction/elimination, and perhaps others for intensification. Ongoing analyses of the remaining samples will extend these conclusions.

No significant financial relationships to disclose.

Haplotypic association spanning the 22q11.21 genes COMT and ARVCF with schizophrenia

Catechol-O-methyltransferase (COMT) has been implicated in schizophrenia by its function through its roles in monoamine neurotransmitter metabolism and its impact on prefrontal cognition, and also by its position through linkage scans and a strong cytogenetic association. Further support comes from association studies, especially family-based ones examining the COMT variant, Val(108/158)Met. We have studied eight markers spanning COMT and including portions of the two immediately adjacent genes, thioredoxin reductase 2 and armadillo repeat deleted in velocardiofacial syndrome (ARVCF), using association testing in 136 schizophrenia families. We found nominal evidence for association of illness to rs165849 (P=0.051) in ARVCF, and a stronger signal (global P=0.0019-0.0036) from three-marker haplotypes spanning the 3' portions of COMT and ARVCF, including Val(108/158)Met with Val(108/158) being the overtransmitted allele, consistent with previous studies. We also find Val(108/158)Met to be in linkage disequilibrium with the markers in ARVCF. These findings support previous association signals of schizophrenia to COMT markers, and suggest that ARVCF might contribute to this signal. ARVCF, a member of the catenin family, besides being a positional candidate, is also one due to its function, that is, its potential role in neurodevelopment, which is implicated in schizophrenia pathogenesis by several lines of evidence.

Chemical ablation of the gallbladder: clinical application and long-term observations

BACKGROUND

We investigated whether minicholecystostomy followed by chemical ablation of the gallbladder could be used as a alternative to cholecystectomy in patients at high risk for complications of surgery.

METHODS

From January 1990 through January 2003, 34 patients at high risk underwent minicholecystostomy. Six weeks after the operation, microwave irradiation was provided to burn the mucosa of the cystic duct at locations at 3, 6, 9, and 12 o'clock around the orifice. Each location was treated eight times at 50 mA for 10 sec. Then chemical ablation of the gallbladder was performed by infusing 95% ethanol into the gallbladder cavity for 30 min. For each sclerosis course, the procedure was repeated every 4 h for a total of eight times. Approximately 2 weeks later, the drainage tube was removed from the gallbladder after cholecystography showed that no cavity other than the lumen of the tube remained in the gallbladder.

RESULTS

Patients tolerated the procedure well and were followed with ultrasonography for 2-14 years (mean, 9). Twenty-nine patients had no complications or side effects, and five patients developed a 1.5- to 3- cm mucocele in the gallbladder. The long-term success rate of sclerotherapy was 85.3% (29/34). No recurrent cholecystitis, new stone or formation, canceration were encountered at the site of the gallbladder.

CONCLUSIONS

Minicholecystostomy followed by chemical ablation of the gallbladder was a safe, effective, and simple procedure for treating high-risk patients with acute cholecystitis and/or cholelithiasis.

The prevalence of TT virus and GB virus C/hepatitis G virus infection in individuals with raised liver enzymes but without HBV or HCV infection in Taiwan

The prevalence of TT virus (TTV) and GB virus-C/hepatitis G virus (GBV-C/HGV) infection and the association with raised liver function tests in 546 Taiwanese with negative HBsAg, anti-HCV and HCV RNA was elucidated. They were tested for serum alanine aminotransferase (ALT), GBV-C/HGV RNA, anti-envelope protein 2 antibody (anti-E2) and TTV DNA. Direct sequencing and phylogenetic analyses were performed on 58 isolates for TTV genotype determination. The prevalence of TTV DNA, GBV-C/HGV RNA, anti-E2 and over all GBV-C/HGV exposure was 24.9, 3.4, 8.2 and 11.1%, respectively. Using uni- and multi-variate analyses, male gender and TTV viremia were associated significantly with raised ALT values. Sixty-nine percent of TTV isolates were deduced to be TTV genotype 1 and they had significantly lower mean age than genotype non-1 isolates. In the population, raised ALT may be related to male gender and be attributable to TTV infection but not to GBV-C/HGV among individuals with no evidence of current HBV and HCV infection. TTV genotype 1 is the most prevalent genotype and associated with younger age.

Properties of a proton-translocating nicotinamide nucleotide transhydrogenase from Escherichia coli with alpha and beta subunits linked through fused transmembrane helices

Proton-translocating nicotinamide nucleotide transhydrogenase from Escherichia coli is composed of an alpha and a beta subunit, whereas the homologues mitochondrial enzyme contains a single polypeptide. As compared to the latter transhydrogenase, using a 14-helix model for its membrane topology, the point of fusion is between the transmembrane helices 4 and 6 where the fusion linker provides the extra transmembrane helix 5. In order to clarify the potential role of this extra helix/linker, the alpha and the beta subunits were fused using three connecting peptides of different lengths, one (pAX9) involving essentially a direct coupling, a second (pKM) with a linking peptide of 18 residues, and a third (pKMII) with a linking peptide of 32 residues, as compared to the mitochondrial extra peptide of 27 residues. The results demonstrate that the plasma membrane-bound and purified pAX9 enzyme with the short linker was partly misfolded and strongly inhibited with regard to both catalytic activities and proton translocation, whereas the properties of pKM and pKMII with longer linkers were similar to those of wild-type E. coli transhydrogenase but partly different from those of the mitochondrial enzyme although pKMII generally gave higher activities. It is concluded that a mitochondrial-like linking peptide is required for proper folding and activity of the E. coli fused transhydrogenase, and that differences between the catalytic properties of the E. coli and the mitochondrial enzymes are unrelated to the linking peptide. This is the first time that larger subunits of a membrane protein with multiple transmembrane helices have been fused with retained activity.

IBOX(2-(4'-dimethylaminophenyl)-6-iodobenzoxazole): a ligand for imaging amyloid plaques in the brain

It is well known that overproduction and accumulation of beta-amyloid (Abeta) plaques in the brain is a key event in the pathogenesis of Alzheimer's disease (AD). Previously it was demonstrated that [125I]TZDM, 2-(4'-dimethylaminophenyl)-6-iodobenzothiazole, a thioflavin derivative, was an effective ligand with good in vitro and in vivo binding characteristics. To further improve the initial uptake and washout rate from the brain, important properties for in vivo imaging agents, a novel radioiodinated ligand, 2-(4'-dimethylaminophenyl)-6-iodobenzoxazole ([125I]IBOX, 3), for detecting Abeta plaques in the brain, was synthesized and evaluated. The new iodinated ligand, IBOX, is based on an isosteric replacement of a sulfur atom of TZDM by an oxygen, by which the molecular weight is reduced while the lipophilicity of the iodinated ligand is increased. Partition coefficients (P.C.) of these two ligands were 70 and 124 for TZDM and IBOX, respectively. In vitro binding study indicated that the isosteric displacement yielded a new ligand with equal binding potency to Abeta(1-40) aggregates (K(i) = 1.9 and 0.8 nM for TZDM and IBOX, respectively). Autoradiography of postmortem brain sections of a confirmed AD patient by [125I]IBOX showed excellent labeling of plaques similar to that observed with [125I]TZDM. More importantly, in vivo biodistribution of [125I]IBOX in normal mice displayed superior peak brain uptake (2.08% at 30 min vs 1.57% at 60 min dose/brain for [125I]IBOX and [125I]TZDM, respectively). In addition, the washout from the brain was much faster for [125I]IBOX as compared to [125I]TZDM. Based on the data presented for [125I]IBOX, it is predicted that the brain trapping of this new radioiodinated ligand in the Abeta containing regions will be more favorable than that of the parent compound, [125I]TZDM. Further evaluation of [125I]IBOX is warranted to confirm the Abeta plaque labeling properties in vivo.

Changing prevalence of hepatitis C virus genotypes: molecular epidemiology and clinical implications in the hepatitis C virus hyperendemic areas and a tertiary referral center in Taiwan

To determine the hepatitis C virus (HCV) genotype distribution in Taiwan and to clarify the relationship between genotype and the pathogenesis of HCV infection, 1,164 subjects positive for serum HCV antibodies and HCV RNA from three HCV hyperendemic areas (Masago, Tzukuan, and Taoyuan) and a tertiary referral center in Taiwan were studied during 1995-1997. HCV genotypes and viral loads were determined using Okamoto's method and branched DNA assay, respectively. Genotype 1b was the most prevalent in Tzukuan (61.9%), Taoyuan (76.9%), and the referral center (47.0%). By contrast, genotype 2a was the major HCV type in Masago (63.5%). Prevalence of genotype 1b positively and that of genotype 2a negatively correlated to age, regardless of study populations (P < 0.01). Based on multivariate analysis, the significant factors associated with the presence of cirrhosis, with or without hepatocellular carcinoma, in chronic hepatitis C patients were genotype 1b and age. In conclusion, these results underline that independent HCV outbreaks continue in HCV hyperendemic areas in Taiwan, concomitant with a changing relative prevalence of HCV genotypes in relation to age. Both the correlation of genotype 1b with age (cohort effect) and intrinsic properties of HCV genotypes are probably responsible for the association between genotype and the pathogenesis of HCV infection.