GBV-C/HGV infection in children with chronic hepatitis C

The role of GB virus-C/hepatitis G virus (GBV-C/HGV), a recently identified member of the Flaviviridae family, in children with liver disease is not well understood. The aims of this study were to evaluate the prevalence of GBV-C/HGV and to clarify its pathogenic role in young patients with chronic hepatitis C. Sixty-four Japanese children and adolescents with chronic hepatitis C virus (HCV) infection, with a mean age of 9.8 years, were evaluated retrospectively. Twenty-one (32.8%) of the 64 patients were positive for serum GBV-C/HGV RNA. Only 1 (1.6%) of the 64 patients was positive for antibody against the envelope protein E2 of GBV-C/HGV (anti-E2) and GBV-C/HGV. None of them was positive for anti-E2 alone. There was no significant difference in clinical, virological, or histological characteristics between GBV-C/HGV-positive and GBV-C/HGV-negative patients, except for underlying malignant disease. There was no evidence that GBV-C/HGV might affect the response of HCV to interferon therapy in young patients with chronic hepatitis C. The prevalence of GBV-C/HGV infection in young patients with chronic hepatitis C is similar to that in adult patients with chronic hepatitis C, but E2-seroconversion is observed infrequently. Underlying malignant disease is a risk factor for GBV-C/HGV viremia. GBV-C/HGV does not seem to affect the clinical course of young patients with chronic hepatitis C.

Activation of channel activity of the NMDA receptor-PSD-95 complex by guanylate kinase-associated protein (GKAP)

The channel-associated protein PSD-95 functionally modulates NMDA receptor channels, interacting with the channels via PDZ domain of PSD-95. PSD-95 also interacts with guanylate kinase-associated protein (GKAP) through the guanylate kinase-like domain of PSD-95. Here we report that GKAP markedly potentiates the channel activity of the receptor-PSD-95 complex. However, GKAP had no effect on basic properties of the channels nor on PSD-95-induced changes in channel properties. Thus, GKAP affects the channel activity of the NMDA receptor via PSD-95 quantitatively, which may make signal transmission more efficient at postsynaptic sites.

Dental asymmetry in temporomandibular disorders

In our previous study, it was reported that facial asymmetry due to mandibular lateral displacement (MLD) was significant in patients with temporomandibular disorders (TMD). In this study, dental asymmetry in TMD patients was investigated by means of PA cephalogram and study model. Lateral deviation of the midline of the mandibular occlusal table (PA-mid) and right-left difference of the molar relationship (Molar-Diff.) were examined, and their relationship with MLD was studied. PA-mid and Molar-Diff. were significantly correlated with MLD. In most cases, displaced side of the midline of the lower occlusal table was coincident with that of the mandibular skeletal midline. These results suggest that in TMD patients asymmetries in occlusal relationship of the midline of the mandibular teeth and molars were mainly due to a mandibular skeletal asymmetry and not merely due to a dental malposition on the alveolar basal bone. Many cases had a more distal occlusal relationship of the first molar on mandibular displaced side compared with that on the opposite side. A high incidence of Class II relationship was found (61.8% as a whole) and more remarkable on the mandibular displaced side. Midline discrepancy and right-left difference of the molar relationship seem to be important occlusal characteristics in patients with TMD.

Severe late acute allograft rejection in a child after living-related auxiliary partial orthotopic liver transplantation for ornithine transcarbamylase deficiency

Auxiliary liver transplantation (ALT) is known to correct liver-based metabolic disorders. However, it remains unclear whether the presence of a native liver influences the long-term prognosis of ALT for metabolic diseases. We reported on a 4-yr-old girl who had undergone living-related auxiliary partial orthotopic liver transplantation (APOLT) for ornithine transcarbamylase deficiency and experienced severe late acute rejection 18 months after liver transplantation, during weaning of immunosuppressive agents. Results of histological analysis of the graft indicated very severe acute rejection (rejection activity index, 9/9), and computed tomography revealed graft liver atrophy. These observations suggest the possibility that severe rejection might occur in APOLT, especially during weaning of immunosuppression.

Facial asymmetry in temporomandibular joint disorders

In order to investigate skeletal deviation in patients with internal derangement of the TMJ, facial asymmetry was examined by the frontal cephalogram and compared with a control group of asymptomatic subjects. It was demonstrated that mandibular lateral displacement in the patients was significantly greater than that in the controls. The degree of displacement was significantly related to the cant of the frontal occlusal plane and the frontal mandibular plane, indicating the reduced vertical dimension of the posterior occlusal level and the ramus height on the mandibular displaced side. It is concluded that facial asymmetry due to mandibular lateral displacement is a relatively common problem in patients with internal derangement of TMJ. The cant of the frontal occlusal plane seems to be an important occlusal characteristic related to temporomandibular joint dysfunction.

Molecular and functional characterization of the Rhodopseudomonas palustris no. 7 phosphoenolpyruvate carboxykinase gene

The pckA gene, encoding the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK), was cloned by PCR amplification from the purple nonsulfur bacterium Rhodopseudomonas palustris No. 7. Sequencing of a 2.5-kb chromosomal SmaI-PstI fragment containing the structural gene revealed an open reading frame encoding 537 amino acids, homologous to known pckA genes. Primer extension analysis identified a transcriptional start site 72 bp upstream of the pckA initiation codon and an upstream sequence similar to sigma70 promoters. Studies of a pckA-lacZ gene fusion indicated that when cells were grown in minimal media with various carbon sources, such as succinate, malate, pyruvate, lactate, or ethanol, under both anaerobic light and aerobic dark conditions, the pckA gene was induced in log phase, irrespective of the carbon source. A R. palustris No. 7 PEPCK-deficient strain showed growth characteristics identical to those of the wild-type strain either anaerobically in the light or aerobically in the dark when a C4-dicarboxylic acid, such as succinate or malate, was used as a carbon source. These results indicate that in R. palustris No. 7, an alternative gluconeogenic pathway may exist in addition to PEPCK.

Modulation of the channel activity of the epsilon2/zeta1-subtype N-methyl D-aspartate receptor by PSD-95

A channel-associated protein PSD-95 has been shown to induce clustering of N-methyl D-aspartate (NMDA) receptors, interacting with the COOH terminus of the epsilon subunit of the receptors. The effects of PSD-95 on the channel activity of the epsilon2/zeta1 heteromeric NMDA receptor were examined by injection of PSD-95 cRNA into Xenopus oocytes expressing the NMDA receptors. Expression of PSD-95 decreased the sensitivity of the NMDA receptor channels to L-glutamate. Mutational studies showed that the interaction between the COOH terminus of the epsilon2 subunit of the NMDA receptor and the second PSD-95/Dlg/Z0-1 domain of PSD-95 is critical for the decrease in glutamate sensitivity. It is known that protein kinase C markedly potentiates the channel activity of the NMDA receptor expressed in oocytes. PSD-95 inhibited the protein kinase C-mediated potentiation of the channels. Thus, we demonstrated that PSD-95 functionally modulates the channel activity of the epsilon2/zeta1 NMDA receptor. PSD-95 makes signal transmission more efficient by clustering the channels at postsynaptic sites. In addition to this, our results suggest that PSD-95 plays a protective role against neuronal excitotoxicity by decreasing the glutamate sensitivity of the channels and by inhibiting the protein kinase C-mediated potentiation of the channels.

Clear cell odontogenic carcinoma: A case report and literature review of odontogenic tumors with clear cells

Clear cell odontogenic carcinomas are uncommon epithelial neoplasms that have metastatic potential. We describe such a tumor in a 67-year-old Japanese man with a well-defined, unilocular radiolucent area in the mandible. The tumor was enucleated and has not recurred or metastasized 3 years after surgery. Histologically, the tumor was composed of a predominant clear cell area and a plexiform ameloblastic pattern. The latter was located at the periphery of the tumor. In the English literature, 19 cases of clear cell odontogenic carcinoma, clear cell odontogenic tumor, and clear cell ameloblastoma have been reported. The mean age of the patients at diagnosis was 56.4 years and the gender ratio (M:F) was 8:11. Fourteen tumors were located in the mandible and 5 in the maxilla. Recurrence or metastasis occurred in approximately one half of these patients, and five of the patients died of their disease. More than one half recurrent or metastatic tumors contained palisading clear cells.

Association of tyrosine phosphatases SHP-1 and SHP-2, inositol 5-phosphatase SHIP with gp49B1, and chromosomal assignment of the gene

We have analyzed the molecules participating in the inhibitory function of gp49B1, a murine type I transmembrane glycoprotein expressed on mast cells and natural killer cells, as well as the chromosomal location of its gene. As assessed by SDS-polyacrylamide gel electrophoresis and immunoblot analysis, tyrosine-phosphorylated, but not nonphosphorylated, synthetic peptides matching each of the two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like sequences found in the cytoplasmic portion of gp49B1 associated with the approximately 65-kDa tyrosine phosphatase SHP-1 and approximately 70-kDa SHP-2 derived from RBL-2H3 cells. In addition, the phosphotyrosyl peptide matching the second ITIM-like sequence also bound the approximately 145-kDa inositol polyphosphate 5-phosphatase SHIP. Thus, it has been strongly suggested that the inhibitory nature of gp49B involves the recruitment of SHP-1, SHP-2, and SHIP for the delivery of inhibitory signal to the cell interior upon phosphorylation of tyrosine residues in their ITIMs. The gp49B gene has been found to be in the juxtaposition of its cognate gene, gp49A. The gene pair was shown to locate in the B4 band of mouse chromosome 10. In this region, no conserved linkage homology to human chromosome 19, where the genes for killer cell inhibitory receptors are found, has been identified.

Cyst-like lesion of a developing tooth induced by mandibular fracture

A dentigerous cyst-like formation in the lower canine region caused by mandibular fracture in a 10-year-old boy is reported. His medical history revealed that he had been unconscious for about 2 weeks after traumatic head injuries sustained in a traffic accident, and a complicated mandibular fracture had been left untreated until his dentist diagnosed the lesion. Eleven months after trauma, a dentigerous cyst measuring 20 mm in diameter was found in the fracture area. The lesion was enucleated and the boy's postoperative recovery was uneventful. The mass completely enveloped the developing canine, and epithelial cells proliferated into the connective tissue. However, there was no distinct epithelial lining. Small round cell infiltrations and several vessels with thrombosis were noted in the cyst wall. The cause of cyst formation was considered to be infection of the canine tooth bud and the surrounding soft tissue.

Spontaneous remission of chronic hepatitis C in children

The clinical course of 48 children with chronic hepatitis C (33 boys, 15 girls; mean age: 12.2 years) was monitored for more than 3 years to clarify its natural course. All patients were positive for the second-generation antibody to hepatitis C virus (anti-HCV) and for serum hepatitis C virus (HCV) RNA. All but one patient had a history of blood transfusion. Serum levels of alanine aminotransferase (ALT) had been abnormal for more than 1.5 years. Spontaneous remission defined as a biochemical remission lasting more than 1 year in association with the disappearance of serum HCV RNA, occurred in 4 (8.3%), however, in 25%, HCV RNA was still detectable in the liver even after its disappearance from serum. In this patient, the level of antibody to HCV core antigen (anti-HCV core) did not decrease significantly and serum HCV RNA eventually reappeared. The serum titre of HCV RNA in the 4 children with spontaneous remission was lower than in the remaining 44 children. Spontaneous remission may occur in children with chronic hepatitis C in whom the serum titre of HCV RNA is low and serum level of anti-HCV core decreases significantly. Assessment of the intrahepatic HCV RNA is necessary to confirm complete remission.

CONCLUSION

A low serum titre of HCV RNA and a significant decrease in the serum titre of anti-HCV core were associated with spontaneous remission in children with chronic hepatitis C. Intrahepatic HCV RNA assessment is necessary to confirm complete remission.

Isolation and characterization of invasive and noninvasive variants of a rat bladder tumor cell line

We isolated, in vitro, spontaneous variants of the rat bladder tumor NBT-II cell line with a distinctive morphology. Of five sublines obtained, three (NBT-L1, L2a and L2b) exhibited an elongated shape and moderate to high invasive activity in vitro. The other two sublines (NBT-T1 and T2) formed tight colonies and exhibited very low or negligible invasive activity. The contents of mRNAs coding for E-cadherin and cadherin-associated molecules (alpha-catenin and beta-catenin) were not correlated with the invasive activity of the cells. However, the expression level of the E-cadherin protein, but not those of catenins, was lower in invasive cells (NBT-L1, L2a and L2b) than in noninvasive cells (NBT-T1 and T2). Analysis of mRNAs coding for several growth factors and their receptors showed that the transforming growth factor alpha mRNA content in invasive cells was higher than that in noninvasive cells, and that the content of epidermal growth factor receptor mRNA was low in NBT-T2. Although NBT-II is known to acquire a fibroblastic appearance and cell motility in response to several growth factors, the conditioned media of the invasive sublines hardly affected the morphology or motility of noninvasive cells. These results indicate that the decreased E-cadherin expression is closely associated with the transition from the noninvasive to the invasive phenotype of the bladder tumor cells, and that a post-transcriptional process is important in the control of E-cadherin expression in the cells. These sublines may be useful as models for studies on the progression of bladder tumors.

Structural and functional analysis of the phosphoenolpyruvate carboxylase gene from the purple nonsulfur bacterium Rhodopseudomonas palustris No. 7

The ppc gene, encoding phosphoenolpyruvate carboxylase (PEPC), from Rhodopseudomonas palustris No. 7 was cloned and sequenced. Primer extension analysis identified a transcriptional start site 42 bp upstream of the ppc initiation codon. An R. palustris No. 7 PEPC-deficient strain showed a slower doubling time compared with the wild-type strain either anaerobically in the light or aerobically in the dark, when pyruvate was used as a carbon source.

Molecular cloning of a novel murine cell-surface glycoprotein homologous to killer cell inhibitory receptors

We have isolated a cDNA clone encoding a novel murine cell-surface glycoprotein. This polypeptide is predicted to be composed of a signal peptide of 23 amino acids, an extracellular region of 620 amino acids that contains six immunoglobulin-like domains with five potential N-glycosylation sites, a transmembrane sequence of 20 amino acids, and a cytoplasmic tail of 178 amino acids with four sets of sequences similar to the immunoreceptor tyrosine-based inhibition motif. The relative molecular mass of the mature polypeptide is calculated to be 90,520 Da. The polypeptide, designated as p91, shows striking homologies to human killer cell inhibitory receptors, a murine gp49B1 protein, a bovine Fcgamma2 receptor, and a human Fcalpha receptor. The mRNA of p91 was especially abundant in murine macrophages. Western blot analysis using p91-specific anti-peptide sera detected a 130-kDa polypeptide in macrophages. Surface biotinylation and immunoprecipitation analysis verified the surface expression of the translation products on COS-1 cells transfected with the p91 cDNA, but the cells failed to show any Fc binding activity.

Cloning of dnaK and dnaJ homologous genes from a purple non-sulfur bacterium Rhodopseudomonas species

The dnaK and dnaJ genes were isolated as a cluster from a purple non-sulfur phototrophic bacterium, Rhodopseudomonas species No. 7 by a polymerase chain reaction (PCR) based method. The deduced products of dnaK (631 amino acids) and dnaJ (379 amino acids) were 67% and 56% identical to the respective Escherichia coli gene products. The functions of DnaK and DnaJ could be confirmed by complementation of the respective E. coli mutants.

Characterization of the interaction between synapsin I and calspectin (brain spectrin or fodrin)

We characterized the properties of the interaction between synapsin I and calspectin using purified proteins. The binding assay in the native state using antibodies specific to the tail region of synapsin I revealed that the binding is a high affinity with Kd of 9 nM, which is almost comparable to that of synapsin I to synaptic vesicles and to F-actin. We demonstrated that the head-middle region of synapsin I binds the NH2-terminal domain of beta subunit of calspectin, which also contains an actin binding site. Furthermore, the interaction was significantly inhibited by phosphorylation of synapsin I by cAMP-dependent protein kinase or by Ca2+, calmodulin-dependent protein kinase II. These properties of the interaction between synapsin I and calspectin may help understanding of its modulatory roles in neurotransmitter release.

Ekman-Westborg-Julin syndrome. A case report

A rare case of the Ekman-Westborg-Julin syndrome in a 15-year-old boy is presented. The patient had general macrodontia with gigantic mandibular third molars. Other dental anomalies, such as peak-shaped cuspids, central cusps, dens in dente, multituberculism, and single conical molar roots, were also present.

Cloning and nucleotide sequence of the beta-D-glucosidase gene from Bifidobacterium breve clb, and expression of beta-D-glucosidase activity in Escherichia coli

Genomic DNA encoding a beta-D-glucosidase (EC 3.2.1.21), which has beta-D-fucosidase activity, was cloned from Bifidobacterium breve clb. We sequenced a 1.9-kbp cloned DNA fragment that contained a single open reading frame encoding 460 amino acids with a calculated molecular mass of 51,513 Da. A putative ribosome binding site was found 5 bp upstream of the initiation codon. The amino acid sequence of this beta-D-glucosidase from Bifidobacterium breve clb had 46% identity with that of beta-glucosidase from Microbispore bispore. The enzyme of Bifidobacterium breve clb was expressed in Escherichia coli. A cell-free extract prepared from the recombinant strain showed 80 to 90-fold more beta-D-glucosidase activity than that from Bifidobacterium breve clb. The recombinant enzyme was purified to homogeneity from cell-free extracts of the recombinant strain using 4 column chromatographies. The recovery of enzyme from the recombinant strain was about 138-fold-higher than that of Bifidobacterium breve clb. The enzymatic properties were similar to those of Bifidobacterium breve clb. For application of this recombinant enzyme, we attempted to synthesize a disaccharide that seemed to be specifically assimilated by Bifidobacteria using the condensation activity of the enzyme.