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T Hosaka

Publications and source records attributed to T Hosaka.

At least 19 recordsLinked to original sources
PubMed2005

[Schwannoma arising from brachial plexus with intrathoracic extension; report of a case].

We report a case of schwannoma arising from brachial plexus with intrathoracic extension. An 18-year-old man demonstrated a tumor shadow at the right pulmonary apex area. In the 2-months of follow-up, tumor size had been growing rapidly. Chest computed tomography (CT) and magnetic resonance imaging (MRI) revealed a giant tumor mass infiltrated right lung. We perfomed operation under the posterolateral incision approach. The pathological diagnosis was schwannoma. We resected this tumor safely and conserved with the seventh, eighth cervical nerve of the brachial plexus under posterolateral incision approach.

Adolescent↗
PubMed2004

The novel mutation K87E in ribosomal protein S12 enhances protein synthesis activity during the late growth phase in Escherichia coli.

Resistance to streptomycin in bacterial cells often results from a mutation in the rpsL gene that encodes the ribosomal protein S12. We found that a particular rpsL mutation (K87E), newly identified in Escherichia coli, causes aberrant protein synthesis activity late in the growth phase. While protein synthesis decreased with age in cells in the wild-type strain, it was sustained at a high level in the mutant, as determined using living cells. This was confirmed using an in vitro protein synthesis system with poly(U) and natural mRNAs (GFP mRNA and CAT mRNA). Other classical rpsL mutations (K42N and K42T) tested did not show such an effect, indicating that this novel characteristic is typical of ribosomes bearing the K87E mutant form of S12, although the K87E mutation conferred the streptomycin resistance and error-restrictive phenotypes also seen with the K42N and K42T mutations. The K87E (but not K42N or K42T) mutant ribosomes exhibited increased stability of the 70S complex in the presence of low concentrations of magnesium. We propose that the aberrant activation of protein synthesis at the late growth phase is caused by the increased stability of the ribosome.

Chloramphenicol O-Acetyltransferase↗
PubMed2004

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.

Acute Disease↗
PubMed2004

Single nucleotide polymorphism of the MxA gene promoter influences the response to interferon monotherapy in patients with hepatitis C viral infection.

The biological activity of interferon (IFN) is mediated by the induction of intracellular antiviral proteins, such as 2'-5' oligoadenylate synthetase, dsRNA-activated protein kinase and MxA protein. Among these, MxA protein is assumed to be the most specific surrogate parameter for IFN action. This study was performed to elucidate whether a single nucleotide polymorphism (SNP) (G/T at nt-88) in the promoter region of the MxA gene influences the response to IFN therapy in patients with chronic hepatitis C virus (HCV) infection. Polymorphisms of the MxA gene in 235 HCV patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequency of SNP was compared between sustained-responders (n = 78) and nonresponders (n = 157), as determined by biochemical and virological responses to IFN. Multivariate analysis showed that among all patients, HCV genotype, HCV RNA level and the SNP of the MxA gene were independent and significant determinants of the outcome of IFN therapy [odds ratio 3.8 (95% confidence interval 2.0-7.0), P < 0.0001; 0.27 (0.15-0.50), P < 0.0001; 1.8 (1.0-3.4), P = 0.0464, respectively]. Furthermore, among patients with a low viral load (< or =2.0 Meq/mL), MxA-T-positive patients were more likely to show a sustained response compared with MxA-T-negative patients [2.87 (1.3-6.3); 62%vs 36%; P = 0.0075]. Our findings suggested that the SNP of the MxA gene is one of the important host factors that independently influences the response to IFN in patients with chronic HCV infection, especially those with a low viral load.

Adult↗
PubMed2003

Gonadotropin-releasing hormone increases melatonin release in the pineal gland of the female rat in vitro.

To evaluate the effect of gonadotropin-releasing hormone (GnRH) on melatonin ( N-acetyl-5-methoxytryptamine) release and its synthesizing enzyme activities in pineal glands, pineals from adult female rats during diestrus were organ-cultured in a medium containing 10 -12, 10 -10, or 10 -8 M GnRH for 6 h. Melatonin release increased significantly in pineals cultured with 10 -10 and 10 -8 M GnRH compared to controls. However, in pineal glands that were organ-cultured in a medium containing 10 -12 to 10 -8 M GnRH, the activity of arylalkylamine N-acetyltransferase, which is the key regulatory enzyme in melatonin biosynthesis, showed no significant difference from controls. Likewise, GnRH at these concentrations had no significant effect on the activity of pineal hydroxyindole- O-methyltransferase, which catalyzes the final step of melatonin biosynthesis. These results show that GnRH stimulates pineal melatonin release, but suggest that GnRH does not affect its melatonin synthesis.

Acetylserotonin O-Methyltransferase↗
PubMed2003

[Radiofrequency ablation for metastatic lung tumor].

BACKGROUND: Radiofrequency ablation (RFA) is a thermal ablation technique which results in coagulative necrosis. Several preliminary studies have evaluated the efficacy of RFA for liver tumor and benign prostate disease, but few studies for lung tumor. We experienced RFA for a metastatic lung tumor and it was effective. CASE: A 61-year-old woman was admitted to our hospital with chest pain. Extended thymothymomectomy with lymph node dissection was performed after diagnosis of thymic carcinoid. After 14 months, multiple small lung nodules, which had been 5-10 mm in diameter, were appeared and resected. However, 23 months after the first operation and 14 months after the second operation, multiple small lung nodules were appeared again and RFA was performed for 1 tumor without any complications. We used RITA 500 PA (RITA Medical Systems, INC.) and quadruple-hook radiofrequency probe with electrodes. Under local anaesthesia and ultrasound guidance, the probe was inserted into the target tumor and the hooks were deployed. The tumor became smaller (35 mm to 25 mm in diameter) in 2 months. CONCLUSION: RFA is an effective and minimally invasive technique to destruct local tumors.

Carcinoid Tumor↗
PubMed2003

[Spontaneous regression of thymoma; report of a case].

A 44-year-old woman was admitted to our hospital with chest pain. Chest roentgenograms and computed tomography (CT) scan revealed an anterior mediastinal tumor and bilateral pleural effusion. However, CT scan 3 days after magnetic resonance imaging (MRI) revealed regression of the tumor. Extended thymo-thymectomy was performed via median sternotomy. The tumor was in the right lobe of the thymus. Pathologically the tumor was diagnosed as a mixed type non-invasive thymoma, but some parts of the tumor cells were necrotic. This is the 10th case of spontaneous regression of thymoma reported in the Japanese literature.

Adult↗
PubMed2003

[The establishment of the styles of video-assisted thoracoscopic surgery for spontaneous pneumothorax].

Video-assisted thoracoscopic surgery (VATS) has been widely used in the treatment of a pneumothorax, but the high incidence of recurrence from spontaneous pneumothorax after VATS is an important problem. In this study, we classified the groups into two categories from the thoracoscopic observations, and discussed whether or not there was reappearance of pneumothorax. In addition, we examined whether adjunctive procedure contributes to recurrent of pneumothorax after operation or not. We concluded that there is a tendency to recurrence in the group with multiple and skip lesions in the lung, and then concluded that the cases apical covering with absorbable material sheet and the use of fibrin glue spray was thought to be effective of recurrence of pneumothorax in cases of multiple and skip lesions from the intraoperative findings through the thoracoscopes. Finally, we examined application of Foley catheter for spontaneous pneumothorax under VATS. It is possible that the application of Foley catheter to prevention against recurrence of pneumothorax is a valid method.

Adult↗
PubMed2002

Stimulatory effects of LH on release of melatonin and activities of its synthesizing enzymes NAT and HIOMT in organ-cultured pineal glands of female rats.

The pineal hormone melatonin (N-acetyl-5-methoxytryptamine) exerts antigonadotropic effects in some mammalian species. To evaluate the effect of luteinizing hormone (LH) on melatonin release and its synthesizing enzyme activities in pineal glands, pineals of adult female rats undergoing diestrus were organ-cultured in a medium containing 10(-12), 10(-10) or 10(-8) M LH for 6 h. Melatonin release increased significantly in pineals cultured with 10(-12) and 10(-10) M LH, as compared to control values. Similarly, the activity of arylalkylamine N-acetyltransferase (NAT), the key regulatory enzyme in melatonin biosynthesis, was significantly higher in pineals cultured with 10(-12) and 10(-10) M LH for 6 h, while LH at 10(-8) M had no effect. Although LH at 10(-10) M increased pineal hydroxyindole-O-methyltransferase (HIOMT) activity, which catalyzes the final step of melatonin biosynthesis, LH at 10(-12) and 10(-8) M had no effect. These results demonstrate that at relatively low physiological levels, LH stimulates pineal melatonin synthesis and release, mainly by increasing NAT activity.

Acetylserotonin O-Methyltransferase↗
PubMed2001

Potent and selective ET-A antagonists. 2. Discovery and evaluation of potent and water soluble N-(6-(2-(aryloxy)ethoxy)-4-pyrimidinyl)sulfonamide derivatives.

In the preceding article,(1) we outlined the discovery and structure-activity relationship of a potent and selective ET(A) receptor antagonist 1 and its related compounds. Metabolites of 1 having potent selective ET(A) receptor antagonist activity were identified. This study suggested the metabolic pathways of 1 were considerably affected by species. Consequently, structural modification of 1 intended to improve the complexity of the metabolic pathway, and water solubility was performed. The subsequent introduction of a hydroxyl group into the tert-butyl moiety of 1 led to the discovery of our new clinical candidate, 6b, which showed a higher water solubility, a uniform metabolic pathway among species, and very high affinity and selectivity for the human ET(A) receptor (K(i) for ET(A) receptor: 0.015 +/- 0.004 nM; for ET(B) receptor: 41 +/- 21 nM).

Animals↗
PubMed2001

Potent and selective ET-A antagonists. 1. Syntheses and structure-activity relationships of N-(6-(2-(aryloxy)ethoxy)-4-pyrimidinyl)sulfonamide derivatives.

Modifications to the ET(A/B) mixed type compounds 1 (Ro. 46-2005) and 2 (bosentan) were performed. Introduction of a pyrimidine group into 1 resulted in a dramatic increase in affinity for the ET(A) receptor, and the subsequent optimization of substituents on the pyrimidine ring led us to the discovery of N-(6-(2-((5-bromo-2-pyrimidinyl)oxy)ethoxy)-5-(4-methylphenyl)-4-pyrimidinyl)-4-tert-butylbenzenesulfonamide (7k), which showed an extremely high affinity for the human cloned ET(A) receptor (K(i) = 0.0042 +/- 0.0038 nM) and an ET(A/B) receptor selectivity up to 29 000 (K(i) = 130 +/- 50 nM for the human cloned ET(B) receptor). The compound was designed on the hypothesis that the hydrogen atom of the hydroxyl group in 1 and 2 played a role not as a proton donor but as an acceptor in the possible hydrogen bonding with Tyr129. Since the incorporation of a pyrimidinyl group into the hydroxyethoxy side chain of the nonselective antagonist (1) dramatically enhanced both the ET(A) receptor affinity and selectivity, and since similar results were obtained from the benzene analogues, we put forward the hypothesis that a "pyrimidine binding pocket" might exist in the ET(A) receptor.

Animals↗
PubMed2001

Fatigue in ambulatory patients with advanced lung cancer: prevalence, correlated factors, and screening.

Although it has been indicated that patients with lung cancer experience higher level of fatigue than patients with other cancers, few published studies have focused on the characteristics of this fatigue and how it interferes with daily activities. The purpose of this study was to clarify fatigue prevalence and the factors correlated with fatigue, and to develop a screening method for fatigue in patients with advanced lung cancer. One hundred fifty-seven patients completed two fatigue scales (Cancer Fatigue Scale [CFS], and Fatigue Numerical Scale [FNS]) plus other measures, along with a self-administered questionnaire asking whether fatigue had interfered with any of 7 areas of daily activities. Fifty-nine percent of patients had experienced clinical fatigue, which was defined as fatigue that interfered with any daily activities. Logistic regression analysis demonstrated that symptoms of dyspnea on walking, appetite loss, and depression were significant correlated factors. Both CFS and FNS were found to have sufficient sensitivity and specificity for use as a screening tool. The results indicated that fatigue is a frequent and important symptom, which is associated with both physical and psychological distress in this population. The CFS and FNS were confirmed to have sufficient screening ability.

Adult↗
PubMed2001

Increased natural killer-cell activity is associated with infertile women.

PROBLEM: An increase in natural killer (NK)-cell activity has been observed in women with unexplained recurrent miscarriages. Because of the many similarities between infertility and early pregnancy loss patients, we investigated whether infertile women had raised NK-cell activity. METHOD OF STUDY: We tested 94 infertile women who, in spite of treatment, were unable to conceive for 6 or more months. NK-cell activity was measured by using a chromium-51 release cytotoxicity assay. with K562 human myeloid leukemia cells as targets. RESULTS: NK-cell activity of the infertile group (mean +/- SD; 40.2%+/-14.7) was significantly higher than the control group (31.5%+/-11.9, P < 0.0001). The increased NK-cell activity was not associated with age, infertile duration, depression scores, treated hyperprolactinemia, or treated endometriosis. CONCLUSIONS: In certain patients, elevated NK-cell activity may be considered an independent risk factor for infertility.

Abortion, Spontaneous↗
PubMed2001

Emotional distress of infertile women in Japan.

Although recent papers have suggested that psychological factors are implicated in the experience of infertility, few studies have assessed this relationship in a sample of Japanese infertile women. This study was carried out in order to clarify whether Japanese infertile women experience emotional distress. A cross-sectional questionnaire study was performed to assess the psychological states of 101 infertile women compared to 81 healthy pregnant women. The hospital anxiety and depression scale (HADS) and the profile of mood states (POMS) were administered. These questionnaires produced scores for depression/dejection, anxiety, aggression/hostility, lack of vigour, fatigue, tension anxiety, and confusion. The HADS and the POMS scores of infertile women were significantly higher than those of pregnant women, except for fatigue score. Infertile women with positive HADS indicating emotional disorders (39/101, 38.6%) were significantly (P = 0.0008, chi(2) test) more than those of pregnant women (13/81, 16.0%) when the threshold was set at 12/13 of total HADS scores. The HADS scores were not affected by the women's age, duration of infertility, experience of conception, routine tests, and work states. In this Japanese population, infertile women reported higher levels of emotional distress than pregnant women, suggesting psychological support is needed for infertile women.

Adult↗
PubMed2001

Characterization of the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase gene from Bacillus cereus YUF-4.

A 1.4-kbp DNA fragment, including the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase (AACRII/BDH) gene from the chromosomal DNA of Bacillus cereus YUF-4, was cloned in Escherichia coli DH5alpha after its insertion into pUC119, and the resulting plasmid was named pAACRII119. The AACRII/BDH gene had an open reading frame consisting of 1047 bp encoding 349 amino acids. The enzyme exhibited not only AACR activity, but also BDH activity. However, the gene was not located in a 2,3-butanediol (BD) operon, as is the case in the BDH gene of Klebsiella pneumoniae and that of K. terrigena. In addition, there was no BD-cycle-related enzyme gene in the region surrounding the AACRII/BDH gene. The AACR and BDH activities in E. coli DH5alpha/pAACRII119 were 200-fold higher than those in the original B. cereus YUF-4. The characteristics of the AACRII/BDH from E. coli DH 5alpha/pAACRII119 are similar to those of the AACRII/BDH from B. cereus YUF-4. The AACRII/BDH was considered to belong to the NAD(P)- and zinc-dependent long-chain alcohol dehydrogenase (group I ADH) family on the basis of the following distinctive characteristics: it possessed 14 strictly conserved residues of microbial group I ADH and consisted of about 350 amino acids. The enzymatic and genetic characteristics of AACRII/BDH were completely different from those of BDHs belonging to the short-chain dehydrogenase/reductase family. These findings indicated that the AACRII/BDH could be considered a new type of BDH.

Journal Article↗