The mandibular response to occlusal relief using a flat guidance splint

Background

The mechanism of action of occlusal splints used for the successful treatment of temporomandibular disorders (TMD) remains unclear and controversial.

Aim

The aim of this study was to observe the mandibular response during sleep bruxism (SB) on the elimination of occlusal influences by using a flat anterior and lateral guidance splint (FGS).

Material and method

Any changes in mandibular movement patterns and condylar position with the introduction of this tool were measured. Current SB activity on the natural dentition was evaluated using a Brux Checker® (BC) and compared with the activity after insertion of an FGS in 153 subjects.

Result

The spatial mandibular position changed individually with a tendency toward forward and downward movement. The insertion of an FGS led to a change in the topographical condyle-fossa relationship and seemed to create an “unloading” condition for the temporomandibular joint. It was found that increased angulation of the maxillar incisors was responsible for altered muscular activity during sleep.

Conclusion

The masticatory organ appears to self-regulate and to provide an oral behavior modification, which may be more physiological using the FGS as a compensating factor. In this context, it is assumed that sleep bruxism in terms of parafunctional activity is a physiological function of the masticatory organ. The results of this study indicate the importance of controlling anterior guidance in the functional reconstruction of human occlusion.

A lower starting dose of eltrombopag is efficacious in Japanese patients with previously treated chronic immune thrombocytopenia

BACKGROUND

Eltrombopag is an oral, non-peptide thrombopoietin receptor agonist that has shown efficacy and safety in chronic immune thrombocytopenia (ITP). However, ethnic differences in eltrombopag exposure have been reported: area under the curve exposure to eltrombopag was 87% greater among ITP patients of East Asian descent than among ITP patients of non-East Asian ITP descent.

OBJECTIVES

To evaluate the efficacy and safety of eltrombopag by using, in Japanese ITP patients, lower starting (12.5 mg) and maximum (50 mg) doses of eltrombopag than the standard starting (50 mg) and maximum (75 mg) doses approved in the USA and Europe.

PATIENTS

We examined 23 Japanese patients with previously treated chronic ITP with a platelet count of < 30,000 μL(-1) in a multicenter study comprising a randomized, double-blind, placebo-controlled phase for 6-week evaluation (15 eltrombopag, and eight placebo) and an open-label phase for 6-month evaluation (23 eltrombopag).

RESULTS AND CONCLUSIONS

The response rate (platelet count of ≥ 50,000 μL(-1) ) at week 6 of the 6-week double-blind phase was 60% in eltrombopag-treated patients and 0% in placebo-treated patients. Ten of 23 patients (43.5%) responded for ≥ 75% of predefined assessment visits during the 6-month open-label phase. Notably, 22% (5/23) of patients responded to 12.5 mg of eltrombopag, which was administered within the first 3 weeks of eltrombopag treatment. Bleeding decreased with eltrombopag treatment as compared with baseline. Eltrombopag was generally well tolerated; one patient experienced a transient ischemic attack on day 9. Eltrombopag (12.5-50 mg) is effective for the management of Japanese patients with chronic ITP (NCT00540423).

Development of thrombopoietin receptor agonists for clinical use

Thrombopoietin (TPO) is an essential hematopoietic cytokine for megakaryopoiesis. In 2002, we demonstrated that pegylated-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) increased platelet counts in patients with chronic immune thrombocytopenic purpura (ITP) in a Phase I/II clinical trial. After the cessation of clinical trials of PEG-rHuMGDF because of severe thrombocytopenia or pancytopenia due to the development of the neutralizing antibody cross-reacting with endogenous TPO, second generation non-immunogenic TPO receptor agonists have been developed. A small molecule eltrombopag and Romiplostim were approved for clinical use by FDA in 2008 to treat patients with chronic ITP who are refractory to the prior therapy. Although the efficacy of both TPO receptor agonists is convincing for the refractory ITP, further investigation is necessary to assess the potential long-term side effects and clinical applications of these therapies for other thrombocytopenic conditions.

Age-specific antibody to hepatitis E virus has remained constant during the past 20 years in Japan

We investigated the presence of antibodies to hepatitis E virus (anti-HEV) and hepatitis A virus (anti-HAV) by enzyme immunoassays in sera from 1015 individuals collected in 1974, 1984 and 1994. Age-specific profiles of anti-HEV remained unchanged with a peak at 40-49 years, while those of anti-HAV started to increase in individuals aged 20-29 years in 1974, 30-39 years in 1984 and 40-49 years in 1994. These results suggest that a silent HEV infection has been taking place in the last 20 years or so in Japan, while HAV infection has been terminated at least since 1974.

Association of interleukin-18 gene single-nucleotide polymorphisms with susceptibility to inflammatory bowel disease

Interleukin-18 (IL-18) is believed to be one of the most important cytokines in the pathogenesis of inflammatory bowel disease (IBD). The aim of the study was to clarify the significance of single-nucleotide polymorphisms (SNPs) at the 5'-end of the IL-18 gene in the development of IBD. DNA was obtained from peripheral blood of 99 patients with ulcerative colitis (UC), 79 patients with Crohn's disease (CD), and 102 healthy controls. All participants were Japanese. SNPs at -656G/T, -607C/A, -137G/C, +113T/G, and +127C/T were determined by means of direct sequencing, and a genetic association with IBD was examined. The frequencies of the G allele at +113 and the T allele at +127 were significantly higher in patients with CD and UC compared with controls. The differences in allelic frequencies were more striking in patients with CD than in patients with UC, and at position +127 than at position +113. The haplotype estimation, according to the E-M algorithm, suggested that TACGT is closely associated with IBD, especially with CD. It was concluded that SNPs at the 5'-end of IL-18 gene might be closely related to the etiology of IBD.

Wild-type precore and core promoter sequences in patients with acute self-limited or chronic hepatitis B

BACKGROUND

Mutations in the precore region and core promoter were compared between patients with acute and chronic hepatitis B.

METHODS

There were 69 patients with acute self-limited hepatitis B and 210 with chronic hepatitis B who had been followed for > 15 years. The hepatitis B virus (HBV) of genotypes A, B and C was detected in 14 (23%), 8 (13%) and 28 (45%) of the patients with acute self-limited hepatitis, respectively, in contrast to 11 (5%), 25 (12%) and 167 (80%) of those with chronic hepatitis.

RESULTS

At presentation, hepatitis B e antigen (HBeAg) in serum was the more common (82% versus 65%, P < 0.05), and the wild-type sequences of the precore region (100% versus 74%, P < 0.001) and core promoter (88% versus 36%, P < 0.00001) were more frequent in the 50 patients with acute self-limited hepatitis than the 203 patients with chronic hepatitis B who were infected with HBV of genotype A, B or C. Wild-types of both the precore region and core promoter persisted in acute self-limited hepatitis, while they decreased from 28% to 10% in chronic hepatitis over the course of > 15 years.

CONCLUSION

HBV with the wild-type sequences of the precore region and core promoter prevails in patients with acute self-limited hepatitis, unlike in patients with chronic hepatitis.

The roles of phosphatidylinositol 3-kinase and protein kinase Czeta for thrombopoietin-induced mitogen-activated protein kinase activation in primary murine megakaryocytes

Thrombopoietin (TPO) stimulates a network of intracellular signaling pathways that displays extensive cross-talk. We have demonstrated previously that the ERK/mitogen-activated protein kinase pathway is important for TPO-induced endomitosis in primary megakaryocytes (MKs). One known pathway by which TPO induces ERK activation is through the association of Shc with the penultimate phosphotyrosine within the TPO receptor, Mpl. However, several investigators found that the membrane-proximal half of the cytoplasmic domain of Mpl is sufficient to activate ERK in vitro and support base-line megakaryopoiesis in vivo. Using BaF3 cells expressing a truncated Mpl (T69Mpl) as a tool to identify non-Shc/Ras-dependent signaling pathways, we describe here novel mechanisms of TPO-induced ERK activation mediated, in part, by phosphoinositide 3-kinase (PI3K). Similar to cells expressing full-length receptor, PI3K was activated by its incorporation into a complex with IRS2 or Gab2. Furthermore, the MEK-phosphorylating activity of protein kinase Czeta (PKCzeta) was also enhanced after TPO stimulation of T69Mpl, contributing to ERK activity. PKCzeta and PI3K also contribute to TPO-induced ERK activation in MKs, confirming their physiological relevance. Like in BaF3 cells, a TPO-induced signaling complex containing p85PI3K is detectable in MKs expressing T61Mpl and is probably responsible for PI3K activation. These data demonstrate a novel role of PI3K and PKCzeta in steady-state megakaryopoiesis.

Determination of hepatitis B virus genotype G by polymerase chain reaction with hemi-nested primers

Hepatitis B virus (HBV) has been classified into six genotypes designated A-F by sequence divergence in the entire genome exceeding 8%. Very recently, the seventh genotype was reported and named genotype G. HBV genotype G is distinct from genomes of the other six genotypes in that it possesses an insertion of 36 nucleotides in the core gene, and has been found so far in France and the United States. A method for determining HBV genotype G was developed by polymerase chain reaction (PCR) with primers deduced from the 36-nucleotide (nt) insertion in five isolates of HBV genotype G the sequences of which have been deposited in DNA databases. The validity of this method, for specifically detecting HBV genotype G, was verified on a panel consisting of 142 HBV isolates of six major genotypes and four of genotype G. A total of 540 sera containing HBV in Japan covering symptom free carriers and patients with a spectrum of chronic liver disease were tested by this method, but not a single HBV genotype G sample was found. A possible method for serological determination of hepatitis B surface antigen of genotype G is suggested, without amplification or sequencing nucleotides, which would expand epidemiological and clinical researches on HBV genotype G.

Expression of prolactin gene in spontaneous mammary tumors in aging Fischer 344 rats

Expression of extra pituitary prolactin (PRL) has been recently reported in the mammary gland. However, spontaneous mammary tumors occurring in aging rats have not been investigated for PRL production. The present study was undertaken to examine the expression of PRL gene in rat mammary tumors spontaneously arisen in rats with pituitary prolactinomas among 130 female Fischer-344 (F-344) rats. The tumors examined were fibroadenoma (adenomatous type) in the 18-month old rat and adenocarcinoma (alveolar/tubular type) in the 21-month old rat. PRL mRNA was examined by solution and in situ reverse transcription-polymerase chain reaction (RT-PCR) method. The predicted amplified products for PRL mRNA were identified in both tumors, and its expression was confirmed to be in the cytoplasm of epithelial cells. The results of the present study showed that PRL gene is expressed in spontaneously arising mammary tumors.

Rapid downregulation of cyclin D1 mRNA and protein levels by ultraviolet irradiation in murine macrophage cells

DNA damage causes G1 cell cycle arrest through stabilization of p53 and its induction. As this process requires transcription, it takes several hours to achieve cell cycle arrest. We observed that ultraviolet (UV) light induces an immediate G1 arrest by rapid clearance of cyclin D1 in the murine macrophage cell line Bac1.2F5. The rapid disappearance of the cyclin D1 protein after exposure to UV was caused by at least two different mechanisms. In the first mechanism, cyclin D1 mRNA promptly disappeared within 1 min after UV irradiation, although cdk4 mRNA levels were unchanged. In the second mechanism, UV irradiation accelerated the degradation of cyclin D1 protein through the proteasome pathway. The half-life of the cyclin D1 protein was measured by pulse chase analysis and was shortened by UV light. These findings suggest that in the UV-irradiated Bac1.2F5 cells the amount of cyclin D1 protein is regulated at both the mRNA and protein levels. These two clearance mechanisms were also observed in murine bone-marrow-derived macrophages from wild type and p53 -/- mice, indicating that cyclin D1 mRNA and protein levels are independent of p53 function. This machinery might contribute to G1 cell cycle arrest and prevent cells from accumulating further DNA damage.

Thrombopoietin induces phosphoinositol 3-kinase activation through SHP2, Gab, and insulin receptor substrate proteins in BAF3 cells and primary murine megakaryocytes

Thrombopoietin (TPO) is a recently characterized member of the hematopoietic growth factor family that serves as the primary regulator of megakaryocyte (MK) and platelet production. The hormone acts by binding to the Mpl receptor, the product of the cellular proto-oncogene c-mpl. Although many downstream signaling targets of TPO have been identified in cell lines, primary MKs, and platelets, the molecular mechanism(s) by which many of these molecules are activated remains uncertain. In this report we demonstrate that the TPO-induced activation of phosphoinositol 3-kinase (PI3K), a signaling intermediate vital for cellular survival and proliferation, occurs through its association with inducible signaling complexes in both BaF3 cells engineered to express Mpl (BaF3/Mpl) and in primary murine MKs. Although a direct association between PI3K and Mpl could not be demonstrated, we found that several proteins, including SHP2, Gab2, and IRS2, undergo phosphorylation and association in BaF3/Mpl cells in response to TPO stimulation, complexes that recruit and enhance the enzymatic activity of PI3K. To verify the physiological relevance of the complex, SHP2-Gab2 association was disrupted by overexpressing a dominant negative SHP2 construct. TPO-induced Akt phosphorylation was significantly decreased in transfected cells suggesting an important role of SHP2 in the complex to enhance PI3K activity. In primary murine MKs, TPO also induced phosphorylation of SHP2, its association with p85 and enhanced PI3K activity, but in contrast to the results in cell lines, neither Gab2 nor IRS2 are phosphorylated in MKs. Instead, a 100-kDa tyrosine-phosphorylated protein (pp100) co-immunoprecipitated with the regulatory subunit of PI3K. These findings support a model where PI3K activity is dependent on its recruitment into TPO-induced multiphosphoprotein complexes, implicate the existence of a scaffolding protein in primary MKs distinct from the known Gab and IRS proteins, and suggest that, in contrast to erythroid progenitor cells that employ Gab1 in PI3K signaling complexes, utilization of an alternate member of the Gab/IRS family could be responsible for specificity in TPO signaling.

Species-specific TT viruses in humans and nonhuman primates and their phylogenetic relatedness

By means of polymerase chain reaction with a primer pair (NG133-NG147) deduced from the untranslated region (UTR) of TT virus (TTV), TTVs with markedly distinct genomic lengths were recovered from sera of humans and nonhuman primates, and their entire nucleotide sequences were determined. A human TTV [TGP96 of 2908 nucleotides (nt)] was obtained that was about 900 nt shorter than heretofore reported TTVs (3787-3853 nt). Likewise, TTVs of chimpanzee occurred in two distinct genomic sizes [Pt-TTV6 (3690 nt) and Pt-TTV8-II (2785 nt)]. Two TTVs of Japanese macaque [Mf-TTV3 (3798 nt) and Mf-TTV9 (3763 nt)] were comparable in genomic length, but only 55% similar in sequence. These five human and nonhuman primate TTVs, along with TTVs of tamarin [So-TTV2 (3371 nt)] and douroucouli [At-TTV3 (3718 nt)], were compared over the entire nucleotide sequence. Although the seven TTVs were only < or = 55% similar, they share a common genomic organization with two open reading frames (ORFs), designated ORF1 (654-735 amino acids) and ORF2 (91-152 amino acids). The N-terminal sequences of ORF1 proteins were rich in arginine, and sequence motifs necessary for transcription and replication were conserved among them all. Like the human prototype TTV (TA278), all seven TTVs from various animals possessed in common two 15-nt sequences (CGAATGGCTGAGTTT and AGGGGCAATTCGGGC) in the UTR that were covered by NG133 and NG147, respectively. These primers would be instrumental in research on TTVs in previously unexamined species for defining their virological characteristics and evolutionary relationships.

Sequestration of TT virus of restricted genotypes in peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMC) harbored TT virus (TTV) of genotypes (3 and 4) different from those (1 and 2) of free virions in plasma of the same individuals. PBMC may act as a reservoir, and TTV of particular genotypes might have tropism for hematopoietic cells.

A structure-function analysis of serine/threonine phosphorylation of the thrombopoietin receptor, c-Mpl

Thrombopoietin (TPO), the critical regulator of platelet production, acts by binding to its cell surface receptor, c-Mpl. Numerous studies have shown that TPO binding leads to JAK2 kinase activation and Tyr phosphorylation of c-Mpl and several intracellular signaling intermediates, events vital for the biological activity of the hormone. In contrast, virtually nothing is known of the role of Ser or Thr phosphorylation of c-Mpl. By using phosphoamino acid analysis we found that Ser residues of c-Mpl were constitutively phosphorylated in receptor-bearing cells, levels that were increased following exposure of cells to TPO. To identify which residues were modified, and to determine the functional consequences of their phosphorylation, we generated a series of Ser to Ala mutations of a truncated c-Mpl receptor (T69) capable of supporting TPO-induced cell growth. Of the eight Ser within T69 we found that at least four are phosphorylated in TPO-stimulated cells. The mutation of each of these residues alone had minimal effects on TPO-induced proliferation, but substitution of all of the phosphoserine residues with Ala reduced the capacity of the receptor to support cell growth by over 50%. Additionally, the Ser at cytoplasmic position 18 is not detectably phosphorylated. However, the mutation of Ser-18 to Ala nearly abrogates TPO-induced proliferation and co-precipitation of JAK2 with Mpl. This study provides the first systematic analysis of the role of Ser residues in c-Mpl signaling.

The entire nucleotide sequences of two distinct TT virus (TTV) isolates (TJN01 and TJN02) remotely related to the original TTV isolates

TT virus (TTV) has a wide range of sequence divergence by which it is classified into at least 16 genotypes. A TTV isolate of genotype 12 (TJNO1) and another of genotype 13 (TJN02) were sequenced in the entire genome, and compared with the reported TTV isolates. TJN01 and TJN02 had genomic lengths of 3787 and 3794 nucleotides (nt), respectively, which were shorter by 66 and 59 nt than the prototype TTV isolate of genotype 1 (TA278). TJN01 and TJN02 shared the nucleotide sequence with TA278 merely in 53.9% and 55.2%, respectively. They possessed two major open reading frames (ORFs) and the noncoding region with a GC-rich region forming stem-loop structures, which are characteristic of TTV. However, their amino acid sequences in ORF1 were similar to that of TA278 in only 35.4 and 34.0%, respectively; TJN01 was 45.4% similar to TJN02. Comparison with TTV isolates of the same genotype identified hypervariable regions in ORF1 of TJN01 and TJN02, as in the prototype TTV of genotype 1. However, quasispecies were barely observed in them. Furthermore, sequences of hypervariable regions scarcely changed during 2-5.5 years in both TJN01 and TJN02. These results indicate that TTV of genotypes 12 and 13 are much different from the prototype TTV of genotype 1.

Interferon-alpha directly represses megakaryopoiesis by inhibiting thrombopoietin-induced signaling through induction of SOCS-1

Interferon (IFN)-alpha has proven useful for treating several clinical conditions, including chronic viral hepatitis and chronic myeloproliferative and lymphoproliferative disorders. In addition to its well-known antiviral effects, the cytokine exerts antiproliferative effects on many cell types, helping to explain its therapeutic usefulness in these latter conditions. However, this same property accounts for several undesirable effects, including thrombocytopenia, which can interfere with the successful clinical application of IFN-alpha. Unfortunately, the mechanisms responsible for the myelosuppressive effects of the cytokine are incompletely understood. The effects of IFN-alpha on megakaryocyte (MK) development were studied. Using several marrow cell purification techniques and quantitative culture methods, it was found that IFN-alpha directly inhibits thrombopoietin (TPO)-induced MK growth. Previous studies indicated that Janus kinase (JAK) and its substrates mediate the effects of TPO on cellular proliferation and survival. It was found that IFN-alpha directly suppresses TPO-induced phosphorylation of the JAK2 substrates c-Mpl and STAT 5 in a TPO-dependent hematopoietic cell line and of Mpl and STAT3 in primary murine MK. Moreover, IFN-alpha induces SOCS-1 production in these cells, which has been shown to inhibit TPO-induced cell growth. Because SOCS protein expression is induced by many cytokines and has been reported to extinguish signaling from several hematopoietic cytokine receptors, these results identify a molecular mechanism responsible for cytokine receptor cross-talk.

Identification of a Candida albicans homologue of the PHO85 gene, a negative regulator of the PHO system in Saccharomyces cerevisiae

In a screen for the protein kinase genes of the human pathogenic yeast Candida albicans, a putative homologue (CaPHO85) of PHO85, a negative regulator of the PHO system of Saccharomyces cerevisiae, which is one of the cyclin-dependent protein kinases (CDKs), was isolated. An open reading frame (ORF) of this gene was identified encoding a predicted protein of 326 amino acids with a calculated molecular weight of 37.6 kDa. The amino acid sequence is highly homologous to S. cerevisiae Pho85 (62% identity) and its Aspergillus nidulans homologue (70% identity), but less homologous to Cdc28 (50% identity) of S. cerevisiae and to its C. albicans homologue CaCdc28 (49% identity), both of which are also CDK. The coding region for the C. albicans gene was interrupted by an intron of 81 nucleotides near the sequence encoding the N-terminal region, similarly to the case of the S. cerevisiae PHO85 gene. Alignment of CaPho85 with various yeast CDKs revealed that most of the domains for ATP-binding and protein kinase activity are conserved among fungal species. Southern blot analysis indicated that CaPHO85 is most likely present as a single copy gene. This gene complemented the pho85 mutation of S. cerevisiae by transformation.

Circular double-stranded forms of TT virus DNA in the liver

TT virus (TTV) is an unenveloped, circular, and single-stranded DNA virus commonly infecting human beings worldwide. TTV DNAs in paired serum and liver tissues from three viremic individuals were separated by gel electrophoresis and characterized biophysically. TTV DNAs in sera migrated in sizes ranging from 2.0 to 2.5 kb. TTV DNAs in liver tissues, however, migrated at 2.0 to 2.5 kb as well as at 3.5 to 6.1 kb. Both faster- and slower-migrating forms of TTV DNAs in the liver were found to be circular and of the full genomic length of 3.8 kb. TTV DNAs migrating at 2.0 to 2.5 kb, from either serum or liver tissues, were sensitive to S1 nuclease but resistant to restriction endonucleases, and therefore, they were single-stranded. By contrast, TTV DNAs in liver tissues that migrated at 3.5 to 6.1 kb were resistant to S1 nuclease. They migrated at 3.7 to 4.0 kb after digestion with EcoRI, which suggests that they represent circular, double-stranded replicative intermediates of TTV. When TTV DNAs were subjected to strand-specific primer extension and then amplified by PCR with internal primers, those in serum were found to be minus-stranded DNAs while those in liver tissues were found to be a mixture of plus- and minus-stranded DNAs. These results suggest that TTV replicates in the liver via a circular double-stranded DNA.

Differentiation of hepatitis B virus genotypes D and E by ELISA using monoclonal antibodies to epitopes on the preS2-region product

An enzyme-linked immunosorbent assay (ELISA) has been described for serological determination of hepatitis B virus genotypes, using monoclonal antibodies (mAb) against seven distinct epitopes (b, m, k, s, u, f and g) on the preS2-region products of hepatitis B surface antigen (HBsAg). The usefulness of this method for serological detection of genotype E, however, was theoretical, because no HBsAg samples of this genotype were included in the original test panel. Moreover, the predicted serotype of genotype E (bksufg) closely resembled that of genotype D (bksu, bksuf or bksug). Four HBsAg samples of genotype E were tested by the original described ELISA. The epitope g, predicted to be present in these samples by amino acid sequences, was not detected when HBsAg of genotype E was captured on a solid phase by mAb to the common determinant 'a' of HBsAg and then reacted with mAb to g (5156) labeled with horseradish peroxidase. However, the four examples of HBsAg of genotype E were captured by mAb 5156 to g on a solid phase; they were then detected by labeled mAb to the common determinant 'a'. Since epitopes f and g co-occurred on HBsAg of genotype E, HBsAg samples of this genotype were also detected, by 'sandwiching' them between immobilized mAb to g and labeled mAb to f. By contrast, HBsAg of genotype D in 90 sera was not reactive when sandwiched between mAb to f and g. Thus, this modified ELISA enables the serological determination of all six genotypes of HBsAg and, by inference, of hepatitis B virus.

Species-specific TT viruses and cross-species infection in nonhuman primates

Viruses resembling human TT virus (TTV) were searched for in sera from nonhuman primates by PCR with primers deduced from well-conserved areas in the untranslated region. TTV DNA was detected in 102 (98%) of 104 chimpanzees, 9 (90%) of 10 Japanese macaques, 4 (100%) of 4 red-bellied tamarins, 5 (83%) of 6 cotton-top tamarins, and 5 (100%) of 5 douroucoulis tested. Analysis of the amplification products of 90 to 106 nucleotides revealed TTV DNA sequences specific for each species, with a decreasing similarity to human TTV in the order of chimpanzee, Japanese macaque, and tamarin/douroucouli TTVs. Full-length viral sequences were amplified by PCR with inverted nested primers deduced from the untranslated region of TTV DNA from each species. All animal TTVs were found to be circular with a genomic length at 3.5 to 3.8 kb, which was comparable to or slightly shorter than human TTV. Sequences closely similar to human TTV were determined by PCR with primers deduced from a coding region (N22 region) and were detected in 49 (47%) of the 104 chimpanzees; they were not found in any animals of the other species. Sequence analysis of the N22 region (222 to 225 nucleotides) of chimpanzee TTV DNAs disclosed four genetic groups that differed by 36.1 to 50.2% from one another; they were 35.0 to 52.8% divergent from any of the 16 genotypes of human TTV. Of the 104 chimpanzees, only 1 was viremic with human TTV of genotype 1a. It was among the 53 chimpanzees which had been used in transmission experiments with human hepatitis viruses. Antibody to TTV of genotype 1a was detected significantly more frequently in the chimpanzees that had been used in transmission experiments than in those that had not (8 of 28 [29%] and 3 of 35 [9%], respectively; P = 0.038). These results indicate that species-specific TTVs are prevalent in nonhuman primates and that human TTV can cross-infect chimpanzees.

Quasispecies of TT virus (TTV) with sequence divergence in hypervariable regions of the capsid protein in chronic TTV infection

Three hypervariable regions were identified in a central portion of open reading frame 1 of TT virus DNA, which codes for a putative capsid protein of 770 amino acids. TT virus circulates as quasispecies, with many amino acid substitutions in hypervariable regions, to evade immune surveillance of the hosts and to establish a persistent infection.

Effect of interferon on a nonenveloped DNA virus (TT virus) associated with acute and chronic hepatitis of unknown etiology

An unenveloped DNA virus named TT virus (TTV) has been reported in association with acute and chronic hepatitis of unknown etiology. The effect of interferon on TTV was evaluated in the patients with chronic hepatitis C who were coinfected with TTV. TTV DNA was determined by a polymerase chain reaction with heminested primers in the 96 patients with chronic hepatitis C who received interferon-alpha (516 million units in 26 weeks) and followed for 24 months thereafter. TTV DNA was detected in 31 (32%) patients before therapy. TTV DNA became undetectable during interferon therapy and remained absent in 14 (45% of the 31 patients) through 24 months thereafter. The four patients with pretreatment TTV DNA titer > or =10(3)/ml did not respond. These results indicate that TTV is sensitive to interferon, and the response would be inversely correlated with pretreatment viral titers.

The entire nucleotide sequence of a TT virus isolate from the United States (TUS01): comparison with reported isolates and phylogenetic analysis

A nonenveloped and single-stranded DNA virus designated TT virus (TTV) has been reported from Japan in association with hepatitis of unknown etiology. Very recently, the prototype TTV isolate (TA278) of genotype 1 is proven to have a circular genome with 3852 nucleotides. A TTV isolate (TUS01) was recovered from a blood donor in the United States, and its entire circular nucleotide sequence of 3818 nucleotides was determined. It possessed two open reading frames coding for 761 and 156 amino acids, respectively. TUS01 shared 60.5% of the nucleotide sequence with the TA278 isolate from Japan that was longer by 35 nt. The sequence of the noncoding region of 1203 nt was conserved with a similarity of 83.4%. Sequence preservation was much lower for the two open reading frames; nucleotide and amino acid sequences were 54.8 and 37.0% similar, respectively, for one and 55.5 and 38.8% similar for the other. By comparison of a partial sequence of 222 nucleotides among 239 TTV isolates available from various countries, at least 11 genotypes with sequence divergence of >30% were recognized. TUS01 was deduced to be of genotype 11, which has not been reported before. Conserved sequences in the noncoding region could be used as primers for sensitively detecting TTV DNA by polymerase chain reaction. Divergent sequences in coding regions would be useful as primers for distinguishing various TTV genotypes.

Marked genomic heterogeneity and frequent mixed infection of TT virus demonstrated by PCR with primers from coding and noncoding regions

A nonenveloped, single-stranded, and circular DNA virus designated TT virus (TTV) has been reported in association with hepatitis of unknown etiology. TTV has a wide sequence divergence (approximately 52%), by which it is classified into at least 16 genotypes separated by an evolutionary distance of >0.30. Therefore, the detection of TTV DNA by polymerase chain reaction would be influenced by primers deduced from conserved or divergent regions of the genome. Of the 30 sera from healthy individuals, up to 17% tested positive with primers deduced from coding region, much less frequently than up to 93% testing positive with primers from noncoding region. These differences were not attributable to the sensitivity of detection, because a cloned TTV DNA of genotype 1a was detected sensitively (up to 1 copy per test) with primers deduced from either the coding or the noncoding region of the same genotype. Sera testing positive only with noncoding region primers, or those showing higher titers with noncoding than coding region primers, contained TTV DNA strains with sequence divergence of 47-53% from the TA278 isolate of genotype 1a within the N22 region spanning 222-231 nucleotides. Some of the sera contained two or three TTV DNA strains of distinct genotypes. These results indicate TTV strains with extremely high sequence divergence prevailing in healthy individuals and frequent mixed infection with TTV strains of distinct genotypes.

Effect of interferon on a nonenveloped DNA virus (TT virus) associated with acute and chronic hepatitis of unknown etiology

An unenveloped DNA virus named TT virus (TTV) has been reported in association with acute and chronic hepatitis of unknown etiology. The effect of interferon on TTV was evaluated in the patients with chronic hepatitis C who were coinfected with TTV. TTV DNA was determined by a polymerase chain reaction with heminested primers in the 96 patients with chronic hepatitis C who received interferon-alpha (516 million units in 26 weeks) and followed for 24 months thereafter. TTV DNA was detected in 31 (32%) patients before therapy. TTV DNA became undetectable during interferon therapy and remained absent in 14 (45% of the 31 patients) through 24 months thereafter. The four patients with pretreatment TTV DNA titer > or =10(3)/ml did not respond. These results indicate that TTV is sensitive to interferon, and the response would be inversely correlated with pretreatment viral titers.

A common mutation of cholesteryl ester transfer protein gene in dialysis patients

BACKGROUND

In patients on maintenance hemodialysis, a decreased concentration of high-density lipoprotein cholesterol (HDL-C) is an apparent independent risk factor for vascular disease (VD). A common missense mutation of cholesteryl ester transfer protein (CETP) gene, D442G (Asp442 to Gly), increases HDL-C levels, but the mutation may also diminish the activity of reverse cholesterol transport.

METHODS

We compared the genotype distribution of the D442G polymorphism and postprandial serum lipid levels between patients with and without VD in 414 hemodialysis patients.

RESULTS

Serum levels of total cholesterol and HDL-C did not differ in patients with the mutation [group M (+)] and without the mutation [group M (-)] and in patients with and without VD. However, patients with below median HDL-C levels (< 45 mg/dl) had a significantly higher prevalence of VD than those with above median HDL levels (26.0 vs. 15.2%, P < 0.01). Moreover, in this low-HDL-C subgroup, group M (+) patients had a significantly higher prevalence of VD than group M (-) patients (54.5 vs. 24.4%, P < 0.05). In the subgroup, group M (+) patients with VD had higher levels of total cholesterol and a higher atherogenic index than those without VD, whereas group M (-) patients with VD had lower levels of total cholesterol and a lower atherogenic index than those without VD.

CONCLUSIONS

The D442G mutation may be a risk factor for atherosclerotic complications in dialysis patients with HDL-C levels below 45 mg/dl. Atherogenic lipid profiles may promote atherosclerosis in the patients with the mutation, but not in those with no mutation.

Serological detection of hepatitis B virus genotypes by ELISA with monoclonal antibodies to type-specific epitopes in the preS2-region product

An ELISA was developed for serological determination of the six genotypes of hepatitis B virus (HBV) designated A, B, C, D, E, and F. Monoclonal antibodies were raised against genotype-specific epitopes in the preS2-region product, and labeled with horseradish peroxidase. Hepatitis B surface antigen (HBsAg) in sera was captured by immobilized antibodies against the common determinant, and evaluated for reactivity with genotype-specific monoclonal antibodies labeled with the enzyme. Serological genotyping was in complete accord with genotypes determined by S-gene sequences in a panel of 68 sera containing HBV/HBsAg of different genotypes. Of 514 sera with HBsAg from Japan, 507 (98.6%) were genotyped serologically: genotype A was identified in 24 (4.7%); B in 196 (38.1%); C in 282 (54.9%); D in 2 (0.4%); and F in 3 (0.6%). There were no sera containing HBV of genotype E. Likewise, 425 of 446 (95.3%) sera with HBsAg from Brazil, China, India, Indonesia, Kenya, Korea, Nepal, Papua New Guinea, the Philippines, and Thailand were classified into A (25.6%), B (24.2%), C (33.9%), and D (11.7%) genotypes; there were no sera with HBsAg of genotype E or F among them. Some sera unclassifiable by ELISA revealed mixed infection with HBV of distinct genotypes, or contained HBsAg deprived of genotype-specific epitopes by point mutations. The ELISA would be useful for large-scale surveys, because it allows serological detection of HBV genotypes without sequencing nucleotides.

Excretion into bile of a novel unenveloped DNA virus (TT virus) associated with acute and chronic non-A-G hepatitis

Recently, an unenveloped, single-stranded DNA virus named TT virus (TTV) has been reported in association with hepatitis of non-A-G etiology. Five patients with TTV viremia, who received bile drainage or cholecystectomy, were tested for TTV DNA in bile by polymerase chain reaction with heminested primers. TTV DNA was detected in bile from all patients; titers were 10-100 times higher than in serum in 4 and at a comparable level in the remaining 1 patient. TTV DNA was detected in feces, also, in 1 of the 2 patients tested. The buoyant density of TTV in bile from 1 tested patient (1.33-1.35 g/cm3) was the same as that in feces (1.32-1.35 g/cm3). TTV may be secreted via bile into feces in a transmissible form and would spread by a fecal-oral route for deep and wide penetration into the general population.

Infection by an unenveloped DNA virus associated with non-A to -G hepatitis in Japanese blood donors with or without elevated ALT levels

BACKGROUND

An unenveloped, single-stranded DNA virus named TT virus has been found in association with elevated alanine aminotransferase (ALT) levels in recipients of transfusions and has been detected frequently in patients with acute or chronic hepatitis of non-A to -G etiology in Japan. DNA of the TT virus was searched for in blood donors with or without elevated ALT levels.

STUDY DESIGN AND METHODS

A total of 861 blood donors without previous transfusions and who were negative for markers of hepatitis B or C virus infection were tested. DNA of the TT virus was detected by polymerize chain reaction with hemi-nested primers.

RESULTS

TT virus DNA was detected in 62 of 280 (22.1% [95% CI: 18.1-26.6]) donors with elevated ALT levels (mean +/- SD, 89.3 +/- 36.4 U/L; range, 61-301 U/L), which is significantly more frequently (p<0.02) than its detection in 91 of 581 (15.7% [95% CI: 13.2-18.4]) donors with normal ALT (< or = 45 U/L). The frequency of TT virus DNA increased with age, in donors with and without elevated ALT.

CONCLUSION

The detection of TT virus DNA, at a frequency higher in donors with elevated ALT than in those without, strengthens the association of TT virus with non-A to -G hepatitis.

Human acute myeloblastic leukemia-ascites model using the human GM-CSF- and IL-3-releasing transgenic SCID mice

To generate an appropriate model for human acute myeloblastic leukemia (AML), we have successfully established a human hematopoietic growth factor-dependent AML cell line (TF-1 and UT-7/GM)-ascites model using human granulocyte-macrophage colony-stimulating factor (hGM-CSF)- and human interleukin 3 (hIL-3)-releasing transgenic (Tg)-SCID mice. When 1 x 10(7) cells of TF-1, a human erythroleukemia cell line, were transplanted into the peritoneum of irradiated Tg-SCID mice (TF-1 ip/Tg-SCID mice), TF-1 cells grew in both the single cell suspension form (asTF-1) and solid form in ascites and invaded various tissues: lungs, liver, pancreas, and genitals, 3-6 weeks following transplantation. Subsequently, 0.5-1 x 10(7) cells of UT-7/GM, a subline of the UT-7 human megakaryoblastic leukemia cell line, grown in the back of hGM-CSF Tg-SCID mice after subcutaneous inoculation, were transplanted into the peritoneum of other irradiated hGM-CSF Tg-SCID mice. After 4 weeks, UT-7/GM cells (asUT-7/GM) also grew in the same manner as TF-1 cells in hGM-CSF Tg-SCID mice. Analysis of the cells from the peritoneum and tissues by PCR amplifying ALU and human GM-CSF receptor beta sequences and by immunohistochemical staining using anti-human CD45 revealed that they possessed the original characteristics of the parental cells. To confirm the usefulness of this human AML-ascites model, experimental treatment of AML cells grown in these mice was carried out with a differentiation inducer, delta-aminolevulinic acid (deltaALA), which induces hemoglobin synthesis for TF-1 in vitro and is thus regarded as an anti-leukemia drug candidate. Unexpectedly, growth promotion of TF-1 cells was observed in the treated TF-1 ip/hIL-3 Tg-SCID mice without differentiation to erythroid cells after treatment with delta-ALA (5 mM) for 7 days. These results indicate that Tg-SCID mice can support the growth of human hematopoietic growth factor-dependent AML cell lines which are usually rejected by SCID mice, without modification of the parental cell characteristics. In addition, this Tg-SCID leukemia-ascites model may become a useful preclinical tool for estimation of drug efficacy in vivo, since the drug candidate which was promising in vitro did not act in the same manner in vivo.

Distinct genotypes of a nonenveloped DNA virus associated with posttransfusion non-A to G hepatitis (TT virus) in plasma and peripheral blood mononuclear cells

TT virus (TTV) is a nonenveloped, single-stranded DNA virus with little sequence homology to known viruses, and associated with elevated transaminase levels in the patients with posttransfusion hepatitis of unknown etiology. The DNA of TTV was detected, by semi-nested polymerase chain reaction, in peripheral blood mononuclear cells (PBMC) from the 30 healthy individuals with circulating virus in plasma. A sequence of 222 bases was determined on 6-10 TTV DNA clones each from plasma and 6 clones -each from PBMC from eight individuals selected at random from this group. TTV can be classified into genotypes separated by an evolutionary distance > 0.30, which can be divided further into subtypes separated by that of 0.15. Three individuals possessed two different TTV variants of distinct genotypes, with predominant genotypes different between plasma and PBMC. Another possessed TTV of the same genotype in both the plasma and PBMC, but clones with a subtype not seen in plasma were observed in PBMC. A third individual had TTV variants with or without a deletion mutation, and those with the deletion mutation abounded only in PBMC. The remaining three individuals were infected with TTV with the same sequence both in plasma and PBMC. These results indicate that TTV variants with phylogenetic differences could infect the same individual, and that some variants would have a predilection for PBMC. It remains to be seen, however, if TTV replicates in PBMC or whether it has been sequestered before its evolution in the host.

Distinct genotypes of a nonenveloped DNA virus associated with posttransfusion non-A to G hepatitis (TT virus) in plasma and peripheral blood mononuclear cells

TT virus (TTV) is a nonenveloped, single-stranded DNA virus with little sequence homology to known viruses, and associated with elevated transaminase levels in the patients with posttransfusion hepatitis of unknown etiology. The DNA of TTV was detected, by semi-nested polymerase chain reaction, in peripheral blood mononuclear cells (PBMC) from the 30 healthy individuals with circulating virus in plasma. A sequence of 222 bases was determined on 6-10 TTV DNA clones each from plasma and 6 clones -each from PBMC from eight individuals selected at random from this group. TTV can be classified into genotypes separated by an evolutionary distance > 0.30, which can be divided further into subtypes separated by that of 0.15. Three individuals possessed two different TTV variants of distinct genotypes, with predominant genotypes different between plasma and PBMC. Another possessed TTV of the same genotype in both the plasma and PBMC, but clones with a subtype not seen in plasma were observed in PBMC. A third individual had TTV variants with or without a deletion mutation, and those with the deletion mutation abounded only in PBMC. The remaining three individuals were infected with TTV with the same sequence both in plasma and PBMC. These results indicate that TTV variants with phylogenetic differences could infect the same individual, and that some variants would have a predilection for PBMC. It remains to be seen, however, if TTV replicates in PBMC or whether it has been sequestered before its evolution in the host.

Infection with an unenveloped DNA virus (TTV) in patients with acute or chronic liver disease of unknown etiology and in those positive for hepatitis C virus RNA

BACKGROUND/AIMS

An unenveloped single-stranded DNA virus (TTV) has been reported in association with elevated transaminase levels in patients with posttransfusion hepatitis and in those with acute or chronic liver disease of unknown etiology. To further evaluate the association of TTV with liver disease, TTV DNA was searched for in patients with acute or chronic liver disease of various etiologies.

METHODS

TTV DNA was determined by polymerase chain reaction with hemi-nested primers in 64 patients with acute or chronic liver disease of unknown etiology and in 100 with acute or chronic liver disease positive for antibody to hepatitis C virus (HCV) as well as HCV RNA.

RESULTS

TTV DNA was detected in two of the seven (29%) patients with acute hepatitis of unknown etiology, but in none of the four patients with acute HCV-associated hepatitis. It was detected in 27 of the 57 (47%) patients with chronic liver disease of unknown etiology at a frequency significantly higher (p<0.001) than that in 17 of the 96 (18%) patients with chronic HCV-associated liver disease. By contrast, RNA of hepatitis G virus was detected in none of the patients with acute hepatitis, and only in one of the 57 (2%) patients with chronic liver disease of unknown etiology as well as in six of the 96 (6%) patients with chronic HCV-associated liver disease.

CONCLUSIONS

Based on the obtained results, TTV has a role in the development of acute and chronic liver disease of unknown etiology.

Determination of antibodies to TT virus (TTV) and application to blood donors and patients with post-transfusion non-A to G hepatitis in Japan

Recently, a nonenveloped single-stranded DNA virus named TT virus (TTV) has been reported in association with non-A to G post-transfusion as well as sporadic acute and chronic liver disease. A method was developed for the detection of antibody to TTV (anti-TTV) by means of immune precipitation and detection of TTV DNA by the polymerase chain reaction. The test serum was incubated with TTV, recovered from feces of a carrier, and after incubation, the formed immune complexes were precipitated with goat antiserum to human IgG. TTV DNA was sought for by the polymerase chain reaction in both precipitate and supernatant. The detection of TTV DNA in the precipitate, but not in the supernatant, was considered to represent anti-TTV in the test serum. Of the 44 healthy blood donors in Japan, anti-TTV was detected in one of the six (17%) with TTV DNA and 11 of the 38 (29%) without TTV DNA. In the two patients with post-transfusion non-A to G hepatitis, free anti-TTV developed as they cleared TTV in serum. Anti-TTV complexed with TTV in serum, detectable by precipitating sera with goat anti-human IgG and testing for TTV DNA, elicited while the patients had elevated alanine transaminase levels. The determination of anti-TTV would be useful for detecting resolved infection in surveys for exposure to TTV in the general population, and for establishing the mechanism of liver injury associated with TTV infection.