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Biomedical subjects

A Hirata

Publications and source records attributed to A Hirata.

At least 73 records · Page 4Linked to original sources
PubMed2001

Nodular cutaneous amyloidosis and carpal tunnel syndrome due to the amyloidogenic transthyretin His 114 variant.

This is the second report of transthyretin (TTR) amyloidosis in a patient who had ATTR Tyr114His diagnosed by mass spectrometry and gene analysis. This case had some clinical features that differed from those of the first reported cases. The patient, 73-year-old man, complained of generalized cutaneous tubercula that had started at age 68. These tubercula gradually increased in size and became generalized. He felt a slight numbness in his extremities. Clinical and electrophysiological examinations revealed that he had bilateral carpal tunnel syndrome (CTS), whereas there was no clear evidence of sensory and/or motor polyneuropathy. Autonomic symptoms were not present. Biopsy studies revealed that both his tuberculum and his sural nerve contained TTR-related amyloid. In his sural nerve, amyloid deposits were observed mainly in the perineurium, not in the endoneurium, and there was no significant depletion of myelinated fibers. The features of this patient were clinically characterized by generalized cutaneous amyloid deposits and late-onset CTS with a lack of overt polyneuropathy and autonomic dysfunction. The unique clinical features in this case seemed to be consistent with the distribution of amyloid deposits.

Aged↗
PubMed2001

Enhancement of nitrifying biofilm formation using selected EPS produced by heterotrophic bacteria.

The possibility of enhancing nitrifying biofilm formation rate with the aid of selected EPS produced by heterotrophic bacteria was investigated. When EPS production characteristics were examined for four kinds of heterotrophs isolated from a domestic wastewater treatment reactor, two strains obtained from biofilms (B1, B2) exhibited a higher polysaccharide production rate than those from suspended flocs (A1, A2). Among EPS components, the concentration of uronic acids gave a good correlation with flocculation ability, which suggests that acidic polysaccharides play a major role in bioaggregate formation. Addition of 1 g/L D-glucuronic acid as an EPS substitute enhanced the homocoagulation rate of autotrophic Nitrosomonas europaea and altered its zeta potential from ñ30.4 mV to +4.3 mV, which indicates a possibility that particular EPS components produced by heterotrophs are utilized as neutralising reagents for nitrifying biofilm formation. Moreover, when heterotrophic isolates with Nitrobacter winogradskyi were cultured in batch with fabric supports, biofilm formed on the substratum. These experimental results suggest the application of selected EPS for enhancing nitrifying biofilm formation.

Bacteria↗
PubMed2001

Biological nitrogen removal from industrial wastewater discharged from metal recovery processes.

The wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of acids and alkalis such as nitric acid and aqueous ammonia, and of salts such as sodium chloride and sodium sulfate. Biological nitrogen removal from this wastewater was attempted by using a circulating bioreactor system equipped with an anaerobic packed bed and an aerobic three-phase fluidized bed. As a result of acclimating microorganisms with change of the hydraulic residence time, this system effectively removed nitrogen from diluted wastewater (T-N: from 2,000 to 4,000 g/m3), such that the total nitrogen concentration in the effluent met the sewage discharge control criteria in Japan (240 g/m3). The removal ratio of total nitrogen was 90% to 98% and that of ammonia was 80% to 92%. In addition, the characteristic equations for biological treatment were applied to this system on the assumption that both reactions of denitrification in the anaerobic reactor and nitrification in the aerobic reactor can be approximated to a first-order reaction. This simplified approach successfully led to a new analytical method for simulating the optimum volume ratio of anaerobic reactor to aerobic reactor for minimizing the total hydraulic residence time.

Ammonia↗
PubMed2001

[A case of plasmacytoma involving adrenal gland].

We report a case of extramedullary plasmacytoma involving the right adrenal gland. A 52-year-old male was introduced under diagnosis of right adrenal tumor which was found incidentally by computerized tomography in a health check up. Laboratory data showed the presence of M protein and elevation of monoclonal lambda type IgG. It was a hormonally non-active tumor involving the adrenal area. Extramedullary plasmacytoma was confirmed by histological analysis of the resected specimen after laparoscopic right adrenalectomy. Extramedullary plasmacytoma is an uncommon neoplasm and occurs most frequently in the upper respiratory tract and is fairly rare in the adrenal area.

Adrenal Gland Neoplasms↗
PubMed2000

Continuous enzymatic production of peptide precursor in aqueous/organic biphasic medium.

N-(benzyloxycarbonyl)-L-aspartic acid (Z-L-Asp) has generally been used as a carboxyl substrate for the enzymatic synthesis of a precursor of aspartame (synthetic sweetener); however, alternative inexpensive protection groups have been in demand for lowering the total cost of its industrial-scale production. A formyl group (F-) was found to be a more desirable protecting group for the N-terminus of amino acid derivatives due to its low cost of preparation, introduction, and removal. The yield of F-AspPheOMe (N-formyl-L-aspartyl-L-phe- nylalanine methylester), however, was found to be <10% in a conventional aqueous medium. We found that F-L-Asp and L-PheOMe were partitioned mainly to the aqueous phase in an aqueous/organic biphasic medium, whereas F-AspPheOMe partitioned to the organic phase, especially when some extracting agents were added. In this study, simultaneous operation of an enzymatic reaction and a product separation by liquid-liquid extraction was thus applied to the F-AspPheOMe synthesis. We succeeded in synthesizing F-AspPheOMe continuously in an aqueous/tributylphosphate (TBP) biphasic medium with >95% yield, which was about tenfold higher than that in an aqueous monophasic medium.

Organic Chemicals↗
PubMed2000

Sfb2p, a yeast protein related to Sec24p, can function as a constituent of COPII coats required for vesicle budding from the endoplasmic reticulum.

The COPII coat is required for vesicle budding from the endoplasmic reticulum (ER), and consists of two heterodimeric subcomplexes, Sec23p/Sec24p, Sec13p/Sec31p, and a small GTPase, Sar1p. We characterized a yeast mutant, anu1 (abnormal nuclear morphology) exhibiting proliferated ER as well as abnormal nuclear morphology at the restrictive temperature. Based on the finding that ANU1 is identical to SEC24, we confirmed a temperature-sensitive protein transport from the ER to the Golgi in anu1-1/sec24-20 cells. Overexpression of SFB2, a SEC24 homologue with 56% identity, partially suppressed not only the mutant phenotype of sec24-20 cells but also rescued the SEC24-disrupted cells. Moreover, the yeast two-hybrid assay revealed that Sfb2p, similarly to Sec24p, interacted with Sec23p. In SEC24-disrupted cells rescued by overexpression of SFB2, some cargo proteins were still retained in the ER, while most of the protein transport was restored. Together, these findings strongly suggest that Sfb2p functions as the component of COPII coats in place of Sec24p, and raise the possibility that each member of the SEC24 family of proteins participates directly and/or indirectly in cargo-recognition events with its own cargo specificity at forming ER-derived vesicles.

COP-Coated Vesicles↗
PubMed2000

Evaluation of kinetic parameters of biochemical reaction in three-phase fluidized bed biofilm reactor for wastewater treatment.

This study evaluates the kinetic parameters of biochemical reaction in three-phase fluidized bed biofilm reactor from the steady state values of the response of the system to step changes in inlet concentration. It was observed from the outlet biological oxygen demand (BOD(5)) plot of the response of the system that as the inlet BOD(5) was increased, the outlet BOD(5) also increased, reached a peak value and then decreased until it leveled to a new steady state value corresponding to the new inlet concentration level. The increase in BOD(5) was attributed to the accumulation of substrate within the reactor as well as the decrease in biofilm substrate consumption rate as the microorganisms adjusted to the new environment. Using the substrate balance at steady state and assuming Monod kinetics, an equation relating the substrate consumption rate to substrate concentration (BOD(5)) and total biofilm surface area had been established. Monod kinetic parameters were found to be K=2.20g/m(2)/day, K(m)=17.41g/m(3) and K/K(m)=0.13m/day. The ratio K/K(m) can be taken as the indicator for biofilm substrate degradation effectiveness at low substrate concentrations.

Journal Article↗
PubMed2000

Epstein-Barr virus associated B-cell lymphoma of brain developing in myelodysplastic syndrome with c-kit mutation (Try-557 -->stop).

The first case of B-cell lymphoma of brain in a patient with myelodysplastic syndrome (MDS) was reported. A 68-year-old man was admitted because of anemia, fever, and thrombocytopenia and was diagnosed as having MDS (refractory anemia with excess of blasts) on the basis of the findings of bone marrow aspiration and chromosomal analysis. The patient was followed up without chemotherapy, but a brain tumor appeared after 3 years. Histologic and immunohistologic examinations revealed diffuse large B-cell lymphoma. Mutations of the c-kit proto-oncogene (stem cell factor receptor) and the p53 tumor-suppressor gene were examined in the MDS lesion and malignant lymphoma (ML) by the polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) method followed by direct sequencing. The p53 mutation was not found in either MDS or ML, but a nonsense mutation (Try-557 --> stop) in exon 11 of the c-kit, which might lead to dysfunction of tyrosine kinase activity, was detected in MDS. This is the first report of c-kit mutation in MDS. Epstein-Barr virus (EBV) genome was demonstrated in the nucleus of brain ML cells by in situ hybridization with EBV-encoded RNA-1 probe. Immunohistochemistry showed that the tumor cells expressed latent infection gene products, including EBV nuclear antigen-2 and latent membrane protein-1. This pattern of latent gene expression was Lat III, which is usually found in malignant lymphomas developing in immunocompromised hosts. These findings suggest that a profound pancytopenia in MDS resulted in an immunodeficient condition, after which EBV-positive B-cell lymphoma of brain developed.

Aged↗
PubMed2000

Primary leiomyosarcoma of the heart subsequent to double carcinomas of the thyroid and lung.

A 63-year-old woman underwent surgical operations for left lower lung cancer and for thyroid cancer. Nine months later, a third cancer developed in her heart and this tumor was removed by open heart surgery. A pathologic study revealed that the tumor was primary leiomyosarcoma of the heart and thus independent from the previous lung and thyroid carcinomas. This case was regarded as a triple carcinoma including a primary leiomyosarcoma arising from the left atrium. Reports in the literature on primary malignant tumors of the heart are reviewed briefly.

Female↗
PubMed2000

Effect of infusion air pressure on visual field defects after macular hole surgery.

PURPOSE: A defect in the visual field is one of the serious complications of macular hole surgery. We investigated the relationship between the occurrence of visual field defect and the location of infusion cannula and air pressure during fluid-air exchange. METHODS: We studied 100 eyes from 90 patients with macular holes. All patients underwent preoperative and postoperative visual field testing. Vitreous surgery was performed in a standard three-port fashion, with surgically induced posterior vitreous detachment, fluid-air exchange, and sulfur hexafluoride gas injection. We analyzed differences in surgical methods in three groups. In group A, the infusion cannula was placed inferotemporally, and the air pressure was set at 50 mm Hg. In group B, the infusion cannula was placed inferonasally, and the air pressure was set at 50 mm Hg. In group C, the infusion cannula was placed inferotemporally, and the air pressure was set at 30 mm Hg. RESULTS: Eighteen eyes (18%) showed visual field defects after vitrectomy. The defect was always located contralateral to the infusion cannula. There was no statistically significant difference in the incidence of visual field defects in groups A and B. Decreased air pressure reduced the occurrence of visual field defects significantly (24% in group A versus 4% in group C, P = .011). CONCLUSIONS: The location of the visual field defect correlated with the location of the infusion cannula. The incidence of this visual field defect was influenced strongly by the infusion air pressure. The visual field defect may be caused by the mechanical damage of air infusion.

Aged↗
PubMed2000

Prediction of paroxysmal atrial fibrillation in patients with congestive heart failure: a prospective study.

OBJECTIVES: We sought to prospectively determine whether patients with congestive heart failure (CHF) at risk for paroxysmal atrial fibrillation (PAF) could be identified by clinical and study variables including the P-wave signal-averaged electrocardiogram (P-SAECG). BACKGROUND: Although it is important to assess the risk of developing PAF in patients with CHF, it still remains difficult to predict the PAF appearance in patients with CHF clinically. METHODS: The study group consisted of 75 patients in sinus rhythm without a history of PAF, whose left ventricular ejection fraction, as measured by radionuclide angiography, was <40%. These patients underwent P-SAECG, echocardiography and 24-h Holter monitoring; in addition, the plasma concentration of atrial natriuretic peptide (ANP) was measured at study entry. RESULTS: An abnormal P-SAECG was found at study entry in 29 of 75 patients. In the follow-up period of 21 +/- 9 months, the PAF attacks documented on the ECG significantly more frequently occurred in patients with (32%) rather than without an abnormal P-SAECG (2%) (p = 0.0002). The plasma ANP level was significantly higher in patients with rather than without PAF attacks (75 +/- 41 vs. 54 +/- 60 pg/ml, p = 0.01), although there were no significant differences in age, left atrial dimension or high grade atrial premature beats between the groups. The multivariate Cox analysis identified that the variables significantly associated with PAF development were an abnormal P-SAECG (hazard ratio 19.1, p = 0.0069) and elevated ANP level > or =60 pg/ml (hazard ratio 8.6, p = 0.018). CONCLUSIONS: An abnormal P-SAECG and elevated ANP level could be predictors of PAF development in patients with CHF.

Adult↗
PubMed2000

Nifedipine suppresses neointimal thickening by its inhibitory effect on vascular smooth muscle cell growth via a MEK-ERK pathway coupling with Pyk2.

The aim of this study was to determine whether nifedipine could suppress an atherogenic process such as balloon-injured intimal thickening in vivo and the proliferation of vascular smooth muscle cells (VSMC) in vitro. First, we examined the in vivo effect of nifedipine to determine whether it could suppress intimal thickening induced by balloon catheterization. Sprague-Dawley (SD) rats were divided into three groups (L, nifedipine 0.3 mg kg(-1) day(-1); H, nifedipine 3 mg kg(-1) day(-1); C, no nifedipine), and Alzet((R)) osmotic pumps were implanted in their backs for continuous administration. The neointimal layers were completely occupied by proliferated VSMC, and the area ratios of neointima/media treated with nifedipine significantly decreased dose-dependently compared to those of the control. Neither blood pressure nor lipid levels changed among the three groups. We next evaluated the in vitro effect of nifedipine on the proliferation of cultured rat VSMC. Nifedipine decreased the values of [(3)H]-thymidine incorporation and total cellular protein content as well as the levels of phosphorylated extracellular signal-regulated protein kinase (ERK) 1/2, mitogen-activated protein kinase kinase (MEK) 1/2, and even the phosphorylation of Pyk2, in dose-dependent fashions. In addition, nifedipine suppressed the levels of proliferative cell nuclear antigen (PCNA) dose-dependently in both VSMC and balloon-injured thoracic aortae. These results indicate that nifedipine has an inhibitory effect on intimal thickening by attenuating intimal VSMC proliferation, suggesting that nifedipine could be effective for preventing the progression of atherosclerotic plaque as in restenosis after angioplasty.

Actins↗
PubMed2000

Insulin activates p38 mitogen-activated protein (MAP) kinase via a MAP kinase kinase (MKK) 3/MKK 6 pathway in vascular smooth muscle cells.

BACKGROUND: Induction of stress-activated mitogen-activated protein (MAP) kinases such as p38 could be important for the development of cardiovascular diseases since p38 MAP kinase activation stimulates apoptosis, cell growth, prostanoid formation and other cellular dysfunctions when induced by oxidants, hyperosmolarity, or pro-inflammatory cytokines. On the other hand, insulin resistance is one of the most important factors promoting atherogenesis, including cardiovascular diseases, but it is not clear how these different factors transmit their signals intracellularly at the cytosolic and nuclear levels. In this study, we investigated the effect of insulin on p38 mitogen-activated protein (MAP) kinase activation in cultured rat vascular smooth muscle cells (VSMC). MATERIALS AND METHODS: VSMC were obtained from the aortas of male Wistar rats by the media explant technique. After being stimulated by insulin with SB-203580, PD-98059, or GF109203X, the cells were solubilized and the expressions of MAP kinases, MAP kinase kinases and p70 S6 kinase were examined by immunoblot analysis. The amount of DNA synthesis was measured by [3H]thymidine incorporation. RESULTS: Insulin activated p38 MAP kinase phosphorylation in a dose-dependent manner, and the phosphorylation was specifically inhibited by SB-203580, a p38 MAP kinase-specific inhibitor, but not by PD-98059, a specific inhibitor of upstream kinase (MEK), of extracellular signal-regulated kinase (ERK), or GF209203X, a protein kinase C-specific inhibitor. Insulin also activated MAP kinase kinase (MKK) 3/MKK 6 phosphorylation, the upstream kinase of p38 MAP kinase, but neither stress-activated protein kinase (SAPK)/ERK kinase (SEK1/MKK4) nor SAPK/c-jun NH2-terminal protein kinase. Surprisingly, phosphorylation of p70 S6 kinase and an increase of DNA synthesis by insulin were suppressed dose dependently by SB-203580. CONCLUSION: These results have established that insulin activates the p38 MAP kinase cascade via an MKK 3/6 pathway in rat VSMC, independently of a MEK-ERK cascade, and partly regulates cell growth.

Animals↗
PubMed2000

Novel process for enzymatic hydrolysis of proteins in an aqueous two-phase system for the production of peptide mixture.

A novel process for the production of peptide mixtures is proposed. Biologically active peptides were synthesized using a thermolysin-catalyzed hydrolysis of a corn protein (zein) in an aqueous two-phase system. The mixture of peptides which was selectively recovered from the dextran-rich bottom phase had a higher angiotensin-converting enzyme (ACE) inhibitory activity than native zein.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Maximal and minimal motor conduction velocity in amyotrophic lateral sclerosis and X-linked bulbospinal muscular atrophy measured by Harayama's collision method.

Measurement of the maximal (Vmax) and minimal (Vmin) motor nerve conduction velocities was performed in amyotrophic lateral sclerosis (ALS), bulbospinal muscular atrophy (BSMA), and control subjects. The collision method as described initially by Harayama and coworkers was used. This allowed for the correction of the velocity recovery effect (VRE) in Hopf's original method. The purpose of this study is to clarify the controversial results regarding the Vmin and the difference between Vmax and Vmin (Vmax-Vmin) in ALS and to compare these results with BSMA, and clarify the usefulness of Harayama's method. In ALS, a reduction of Vmax and Vmin, and an increase of Vmax-Vmin were found in both median and posterior tibial nerve. In BSMA, a reduction of Vmin and an increase of Vmax-Vmin in the median nerve were noted. Some patients whose results of conventional nerve conduction study were entirely within normal range showed abnormal results in Vmin and/or Vmax-Vmin. These results suggest that the correction of VRE is essential to determine a Vmin, and motor fibers with abnormally slow conduction velocities were present in ALS and BSMA. Harayama's collision method is useful to detect abnormalities of motor fibers with submaximal conduction velocities.

Adult↗
PubMed2000

Symbiobacterium thermophilum gen. nov., sp. nov., a symbiotic thermophile that depends on co-culture with a Bacillus strain for growth.

A Gram-negative and tryptophanase-positive thermophile, whose growth is dependent on co-culture with an associating Bacillus strain, had been reported and tentatively named Symbiobacterium thermophilum strain T(T). Axenic culture of strain T(T) was recently established by dialysing cultures with the supporting bacterial strains or adding their culture broth. Phylogenetic analysis of strain T(T), based on the 16S rDNA sequence, was conducted for the validation of S. thermophilum. The sequence of strain T(T) was located at the outermost position in the high-G+C Gram-positive group distinctly isolated from any other branches hitherto known. Ten sequences identical to that of strain T(T), and one sequence closely related to it, were identified for the first time from soil and compost samples. The outer membrane of strain T(T) had a three-layered structure, outside the cytoplasmic membrane, which is similar to the S-layer in the cells of members of the Bacillaceae. Chemical analysis of the cells revealed that menaquinone-6 is a major component of the quinone system. According to these results, along with several previous observations (i.e. a G+C DNA content of 65 mol% and the identification of iso-C15:0 and iso-C17:0 acids as major cellular fatty acids), the new taxon Symbiobacterium thermophilum gen. nov., sp. nov. is proposed. The type strain is S. thermophilum strain T(T) (= IAM 14863T).

Bacillus↗