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Biomedical subjects

H Tamai

Publications and source records attributed to H Tamai.

At least 37 records · Page 2Linked to original sources

Long-term clinical outcomes after unprotected left main trunk percutaneous revascularization in 279 patients.

BACKGROUND: Percutaneous coronary revascularization (PCI) has been increasingly applied to unprotected left main trunk (LMT) lesions, with varied long-term success. This study attempts to define the predictors of outcome in this population. METHODS AND RESULTS: Two hundred seventy-nine consecutive patients who had LMT PCI at 1 of 25 sites between 1993 and 1998 were studied. Forty-six percent of these patients were deemed inoperable or at high surgical risk. Thirty-eight patients (13.7%) died in hospital, and the rest were followed up for a mean of 19 months. The 1-year incidence was 24.2% for all-cause mortality, 20.2% for cardiac mortality, 9.8% for myocardial infarction, and 9.4% for CABG. Independent correlates of all-cause mortality were left ventricular ejection fraction </=30%, mitral regurgitation grade 3 or 4, presentation with myocardial infarction and shock, creatinine >/=2.0 mg/dL, and severe lesion calcification. For the 32% of patients <65 years old with left ventricular ejection fraction >30% and without shock, the prevalence of these adverse risk factors was low. No periprocedural deaths were observed in this low-risk subset, and the 1-year mortality was only 3.4%. CONCLUSIONS: Patients undergoing unprotected LMT PCI have frequent serious comorbidities and consequently have high event rates. PCI may be an alternative to CABG for a select proportion of elective patients and may also be appropriate for highly symptomatic inoperable patients. Meticulous follow-up of hospital survivors is required because of the rather high mortality during the first few months after treatment.

Aged↗

Identification of susceptibility loci for autoimmune thyroid disease to 5q31-q33 and Hashimoto's thyroiditis to 8q23-q24 by multipoint affected sib-pair linkage analysis in Japanese.

Autoimmune thyroid disease (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT), is caused by multiple genetic and environmental factors. The clinical and immunological features of GD and HT are distinct; however, there are multiplex families with both GD and HT, and cases in which GD evolves into HT. Thus, there may be specific susceptibility loci for GD or HT, and common loci controlling the susceptibility to both GD and HT may exist. A genome-wide analysis of data on 123 Japanese sib-pairs affected with AITD was made in which GD- or HT-affected sib-pairs (ASPs) were studied to detect GD- or HT-specific susceptibility loci, and all AITD-ASPs were used to detect AITD-common susceptibility loci. Our study revealed 19 regions on 14 chromosomes (1, 2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15, 18 and 22) where the multipoint maximum LOD score (MLS) was >1. Especially, chromosome 5q31-q33 yielded suggestive evidence for linkage to AITD as a whole, with an MLS of 3.14 at D5S436, and chromosome 8q23-q24 yielded suggestive evidence for linkage to HT, with an MLS of 3.77 at D8S272. These observations suggest the presence of an AITD susceptibility locus at 5q31-q33 and a HT susceptibility locus at 8q23-q24.

Abatacept↗

Impact of peri-stent remodeling on restenosis: a volumetric intravascular ultrasound study.

BACKGROUND: Vessel remodeling is an important mechanism of late lumen loss after nonstent coronary interventions. However, its impact on in-stent restenosis has not been systematically investigated. METHODS AND RESULTS: Serial volumetric intravascular ultrasound analyses (poststent and follow-up) were performed in 55 lesions treated with a balloon-expandable stent (ACS MultiLink) using standard stent deployment techniques. The vessel volume (VV), lumen volume (LV), and volume bordered by the stent (SV) were measured using Simpson's method. The volume of plaque and neointima outside the stent (peri-stent volume, PSV) and volume of neointima within the stent (intrastent volume) were also measured. The change of each parameter during the follow-up period (follow-up minus poststent) was calculated and then divided by SV to normalize these values (designated as percent change [%]). As expected, %PSV directly correlated with %VV (P<0.0001, r=0.935), with no significant SV. A highly significant inverse correlation was seen between %PSV and the percent change of intrastent volume (P<0.0001, r=0.517). Consequently, %LV significantly correlated with peri-stent remodeling, as measured by %VV (P<0.0001, r=0.602). CONCLUSION: Positive remodeling of the vessel exterior to a coronary stent occurs to a variable degree after stent implantation. There is a distinct trade-off between positive remodeling and in-stent hyperplasia: in segments in which the degree of peri-stent remodeling is less, intrastent neointimal proliferation is greater and accompanied by more significant late lumen loss.

Aged↗

Initial and long-term results of directional coronary atherectomy in unprotected left main coronary artery.

Angioplasty in the unprotected left main coronary artery (LMCA) has been controversial. Recently, several studies have suggested that new procedures and devices such as directional coronary atherectomy (DCA) and stents may change this situation. Although there are many reports of unprotected LMCA stenting, there are few reports of DCA of this lesion. Therefore, initial and long-term results were evaluated in 101 patients who underwent DCA for unprotected LMCA in our hospital. Emergency procedures were performed in 15 patients and electively in 86 patients. Scheduled angiographic follow-up was routinely performed, and all patients were clinically followed for >4 months after DCA. Technical success was achieved in 99%, and in-hospital outcomes were cardiac death (2%), noncardiac death (4%), Q-wave myocardial infarction (1%), non-Q-wave myocardial infarction (8.9%), coronary artery bypass grafting (0%), and repeat angioplasty (4%). In-hospital results varied considerably, depending on presentation. In-hospital mortality was significantly higher in the emergency, left ventricular ejection fraction < or =35%, and high-risk surgical subgroups. The angiographic restenosis rate was 20.4% at follow-up, and its predictor was postminimal lumen diameter by multivariate analysis. Mean clinical follow-up was 2.8 years; estimated 1- and 3-year survival rates were 87% and 80.7%, respectively. The cardiac survival rate of the low-risk surgical subgroup was significantly higher than that of the high-risk surgical subgroup (p <0.05). Thus, our data show that DCA can be performed safely and effectively in unprotected LMCA with an acceptable low restenosis rate and high survival rate.

Adult↗

Coenzyme A stimulates collagen production in cultured fibroblasts; possible mechanisms in enzymatic and gene expression.

Coenzyme A, a cofactor in enzymatic acetyl transfer reactions, stimulates collagen production in cultured fibroblasts. The mechanisms involved in this collagen stimulation were investigated. Enzymatic studies using radiolabeled procollagen as substrate revealed that coenzyme A enhanced prolyl hydroxylase activity. Prolyl hydroxylase is a key enzyme in collagen synthesis acting by hydroxylation of proline residues in procollagen peptide, which is necessary for stabilizing collagen. Northern blot analysis demonstrated that coenzyme A also enhanced mRNA levels of both the alpha subunit of prolyl hydroxylase and the alpha1 chain of type I collagen. The levels of protein production of prolyl hydroxylase and type I collagen were also increased in cultured fibroblasts by coenzyme A, which correlated well with observations from Northern blotting. On the other hand, coenzyme A did not stimulate the activity nor the gene expression of two other processing enzymes: lysyl hydroxylase, which provides the sites for glycosylation and crosslinking between collagen peptides, and lysyl oxidase, a fundamental enzyme in intermolecular crosslinking. These results indicate that coenzyme A stimulates collagen production by at least two separate mechanisms: by enhancing prolyl hydroxylase activity as well as stimulating gene expression of the alpha subunit of this enzyme, and by stimulating gene expression of alpha1 chain of type I collagen.

3T3 Cells↗

Detection and cytotoxicity of cisplatin-induced superoxide anion in monolayer cultures of a human ovarian cancer cell line.

Superoxide anions (O2-) generated by cisplatin [cis-diamminedichloroplatinum (II), DDP] were determined by measuring the chemiluminescence from the luminescence probe, 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (methyl Cypridina luciferin analog, MCLA), in monolayer cultures of a human ovarian cancer cell line (A2780) in physiological saline at pH 7.0. In a time-course study, chemiluminescence of MCLA (C-MCLA) showed a peak level at 10 min and a background level at 60 min after the addition of DDP. The intensity of C-MCLA increased with increasing concentrations of DDP or MCLA in a limited concentration range, and was significantly correlated (r = 0.960) with the number of A2780 cells. DDP-induced C-MCLA was completely inhibited by the addition of the O2- scavenger, superoxide dismutase (SOD). However, SOD did not decrease DDP cytotoxicity in terms of clonogenic cell survival. These findings suggest that DDP generates extracellular O2-, probably by interaction with the cellular membrane in A2780 cells, and O2- does not lead to cellular damage.

Antineoplastic Agents↗

Vitamin B-12-deficiency affects immunoglobulin production and cytokine levels in mice.

To clarify the role of B-12 in the immunological function, serum C3, IgM, IgG, IgE contents, splenocytes expression of CD4, CD8, and CD4 positive intracellular IFN-gamma and IL-4 were examined in B-12-deficient mice, and the effect of the administration of CH3-B-12 was also studied. Serum C3, IgM and IgG contents were lower in B-12-deficient mice than in the control mice. On the other hand, serum IgE content was significantly higher in B-12-deficient mice, and the value in CH3-B-12 administered mice, administered CH3-B-12 to B-12-deficient mice for 48 h before the end of feeding period, showed a tendency to recovery. CD4+CD8- cells and CD4+CD8-/CD4-CD8+ ratio in splenocytes were significantly higher in B-12-deficient mice than in control mice. CD4+IFN-gamma+ cells was significantly lower in B-12-deficient mice than in control mice, and CD4+IL-4+ was significantly higher in B-12-deficient mice than in control mice. These results suggest that B-12-deficiency causes CD4+CD8-T cells shift from the T helper type 1 to the T helper type 2, which participate in the IgE production and elevates CD4+CD8-/CD4-CD8+ ratio. Thus, B-12 plays a role in maintaining the immune function in mice.

Animals↗

Role of endothelin in endotoxin-induced hepatic microvascular dysfunction in rats fed chronically with ethanol.

BACKGROUND: We examined the role of endothelin in endotoxin-induced hepatic microcirculatory disturbance in pair-fed rats given a liquid diet containing ethanol or isocaloric control. METHODS AND RESULTS: One lobe of the liver was observed with the use of an intravital microscope. Erythrocytes (RBCs) labeled with fluorescein isothiocyanate (FITC) were injected, and the flow velocity of the FITC-RBCs in the sinusoids was measured with an off-line velocimeter. The flow velocity decreased 30 min after 1 mg/kg of lipopolysaccharide (LPS) was administered to the controls, and portal pressure (PP) was increased at 60 min. In ethanol-fed rats, however, both the flow velocity and PP increased in the early phase (at 10 min), and in the late phase, flow velocity decreased and PP increased more than in the controls. The LPS-induced decrease in flow velocity was blunted, when BQ-123, an antagonist of endothelin receptor subtype A, was infused into ethanol-fed rats, and BQ-123 also attenuated the change in PP. The plasma endothelin levels in both systemic and portal blood of the ethanol-fed rats were higher than in the controls. CONCLUSIONS: These results suggest that endothelin plays a role in the LPS-induced hepatic microcirculatory disturbance, especially in alcohol-fed animals.

Alanine Transaminase↗

A Japanese herbal medicine, Sho-saiko-to, prevents gut ischemia/reperfusion-induced hepatic microvascular dysfunction in rats.

BACKGROUND AND AIM: We have reported that gut ischemia/reperfusion (I/R) causes hepatic microvascular dysfunction. Nitric oxide (NO) has been found to be a modulator of the adhesive interactions between leukocytes, platelets, and endothelial cells. Sho-saiko-to (TJ-9), a Japanese herbal medicine, is reported to have protective effects against liver injury and to regulate NO production. The objective of this study was to determine whether TJ-9 affects hepatic microvascular dysfunction elicited by gut I/R, and to investigate the role of NO. METHODS: Male Wistar rats were exposed to 30 min of gut ischemia followed by 60 min of reperfusion. Intravital microscopy was used to monitor leukocyte recruitment and the number of non-perfused sinusoids (NPS). Plasma tumor necrosis factor (TNF)-alpha and alanine aminotransferase (ALT) activities were measured. In another set of experiments, TJ-9 (1 g/kg per day intragastrically) was administered to rats for 7 days. In some experiments, dexamethasone (ST) (2 mg/kg per day intravenously) was administered. RESULTS: In control rats, gut I/R elicited increases in the number of stationary leukocytes, NPS, and plasma TNF-alpha and ALT activities, and these changes were mitigated by the pretreatment with TJ-9. Pretreatment with an NO synthase inhibitor diminished the protective effects of TJ-9 on the increase in leukostasis in the pericentral region, NPS, and plasma TNF-alpha levels, but not its effect on the increase in leukostasis in the midzonal region, total number of stationary leukocytes, or plasma ALT activities. Pretreatment with TJ-9 increased plasma nitrite/nitrate levels. The responses caused by gut I/R were attenuated by the pretreatment with ST. Pretreatment with an NO synthase inhibitor did not affect the effect of ST. CONCLUSIONS: These results suggest that TJ-9 attenuates the gut I/R-induced hepatic microvascular dysfunction and inflammatory responses such as TNF-alpha production in the early phase via enhancement of NO production, and sequential hepatocellular damage via its anti-inflammatory effect like corticosteroid effect.

Animals↗

Cerebrospinal fluid and serum neuron-specific enolase levels after febrile seizures.

PURPOSE: Neuron-specific enolase (NSE) has been established as a reliable marker of neuronal damage in various neurologic disorders. The aim of this study was to evaluate whether febrile seizures (FS) cause brain damage, based on the serum and cerebrospinal fluid (CSF) levels of NSE. METHODS: Fifty-three patients aged from 6 months to 7 years were enrolled. Among them, 36 patients had generalized seizures, and 17 had partial seizures. The maximal seizure duration was 90 min. Blood and CSF samples for measurement of NSE were obtained immediately after the seizure. NSE was measured using an enzyme immunoassay (EIA). RESULTS: Serum and CSF levels of NSE ranged up to 10 ng/mL, but very high levels were not observed. In patients with partial seizures, the NSE level in the CSF and the ratio of the CSF to serum NSE levels showed a strong correlation with seizure duration. Conversely, there were no correlations between NSE levels and seizure duration in the patients with generalized seizures. CONCLUSIONS: These results indicate that FS seldom cause severe neurologic damage, but prolonged partial seizures may cause slight neuronal injury.

Biomarkers↗

Duodenal erosions after eradication of Helicobacter pylori infection.

BACKGROUND: There is interest in the development of GERD after Helicobacter pylori eradication. In contrast, the development of duodenal erosions after therapy has received scant attention. Patients were examined after eradication of H pylori infection to determine the frequency of post-therapy duodenal erosions (primary outcome) and whether there was a relation between development of duodenal and esophageal erosions. Additionally, factors were searched for that would identify patients at increased risk for duodenal erosions. METHODS: A single-center, endoscopist-blinded, observational study was conducted of 196 patients in whom H pylori was eradicated. The presence of esophageal or duodenal erosions was evaluated 4 weeks and 6 months after eradication. Serum gastrin and pepsinogen I (PG I) and II (PG II) levels were also determined for 83 patients entering the study during its final year. RESULTS: Multiple small duodenal erosions developed in 8.6% of patients after H pylori eradication and were more common in patients with pre-eradication duodenal ulcer (27.8%) compared with those with gastric ulcer (6.7%) or atrophic gastritis (1.4%) (p < 0.05). Duodenal erosions were associated with high levels of PG I before and after eradication. The frequency of duodenal erosions decreased over time (3.1% by 6 months). CONCLUSION: Duodenal erosions occur after H pylori eradication and appear to be related to duodenal ulcer and increased PG I levels, both of which are associated with increased acid secretion. Measurement of PG I may help to identify patients who have duodenal erosions develop after H pylori therapy for studies of the pathogenesis of these lesions.

Duodenal Ulcer↗

Blood transfusion increases radical promoting non-transferrin bound iron in preterm infants.

BACKGROUND: Blood transfusion has been recognised as a risk factor for the development of retinopathy of prematurity (ROP) or chronic lung disease (CLD) in preterm infants, but the precise mechanism involved is not understood. AIM: To investigate the level of non-transferrin bound "free" iron, which has the potential to promote the generation of reactive oxygen species, and its redox status in the plasma of preterm infants immediately before and after blood transfusion. METHODS: Twenty one preterm infants with a median gestational age and birth weight of 27 weeks and 1021 g respectively were prospectively enrolled in the study. Sixteen of the 21 infants developed ROP and/or CLD. The infants were transfused with concentrated red blood cells at a median age of 32 days. The plasma concentration of total bleomycin detectable iron (BDI) was measured and also the ferrous iron (Fe(2+)) activity by bleomycin-iron complex dependent degradation of DNA. RESULTS: Even before blood transfusion, BDI was detectable in one third of the blood samples, and all but one sample had ferrous iron activity. After transfusion, both BDI and ferrous iron activity were significantly increased, in contrast with the situation in full term infants. Plasma ascorbic acid (AA) concentration was significantly decreased after blood transfusion, whereas the level of its oxidation product, dehydroascorbic acid (DHAA), and the DHAA/AA ratio were significantly increased compared with before the transfusion. The activity of plasma ferroxidase, which converts iron from the ferrous to the ferric state, was appreciably decreased in preterm infants, as expected from their very low plasma caeruloplasmin concentration. CONCLUSIONS: Plasma non-transferrin bound iron was significantly increased in preterm infants after blood transfusion and existed partly in the ferrous form, because of the low ferroxidase activity and the reduction of ferric iron (Fe(3+)) by ascorbic acid. This finding was specific to preterm infants and was not observed in full term infants after blood transfusion. Non-transferrin bound "free" iron may catalyse the generation of reactive oxygen species, which may be responsible for the clinical association of blood transfusion with ROP and CLD.

Anti-Bacterial Agents↗

Primary hepatic Burkitt's lymphoma with chronic hepatitis C.

The liver is an uncommon primary site for malignant lymphoma, and primary hepatic lymphoma has been found to make up 0.4% of all extranodal lymphomas. We report a rare case of a 75-year-old Japanese male with primary hepatic Burkitt's lymphoma, according to both the revised European-American Lymphoma classification and the new World Health Organization classification. As not only histological findings but also immunological features are deemed essential in the diagnosis of Burkitt's lymphoma, the previous 7 cases of primary hepatic Burkitt's lymphoma were not fully evaluated, using these criteria. As far as we know, this is the first case of primary hepatic Burkitt's lymphoma with typical features on histological, immunological and cytogenetical analysis. He had a history of chronic hepatitis C over several decades with subsequent liver cirrhosis. From our review of the literature and our case, the relationship between hepatitis C virus infection and the development of primary hepatic Burkitt's lymphoma remains obscure.

Aged↗

[Usefulness of near-infrared spectroscopy for identification of epileptic foci in two localization-related epilepsy patients].

We monitored cerebral blood volume (CBV) using near-infrared spectroscopy (NIRS) of two patients with symptomatic localization-related epilepsy who had no epileptic discharges in ictal scalp EEG. Case 1 was a 9-month-old boy who was suspected to have frontal lobe epilepsy. Although epileptic discharges were not identified on his ictal EEG due to motion artifacts, NIRS demonstrated an increase of CBV of the left brain during the seizure. Ictal single photon emission CT (SPECT) was dominant at the left side. Case 2 was a 3-year-old girl who was suspected to have temporal lobe epilepsy. Ictal EEG tracings, theta waves revealed prominent but did not enable identification of the focus. She had cortical dysplasia in the right cerebral hemisphere. NIRS monitoring demonstrated an increase in CBV in the right frontal region, which began 10 minutes before the seizure onset and lasted for 3 hours. Thus NIRS is a sensitive and non-invasive procedure for monitoring CBV changes during the seizure, and is useful in identification of the epileptic focus.

Cerebrovascular Circulation↗

[Role of new devices for angioplasty in the unprotected left main coronary artery].

OBJECTIVES: Angioplasty for the unprotected left main trunk remains controversial, but new procedures and devices such as directional coronary atherectomy and stenting have improved the results. We compared the results of angioplasty with the inflexible balloon and new devices. METHODS: The procedures were performed in 239 consecutive lesions in 160 patients between April 1986 and March 2000. This study excluded emergency cases and repeat angioplasty cases, and included 120 initial and elective cases. Initial and long-term results were compared between the balloon group (n = 29) and the new device group (n = 91). RESULTS: Lesion success rate was lower in the balloon group (90% vs 100%, p < 0.05), but there were no significant differences in in-hospital results including cardiac death (0% vs 0%), noncardiac death (0% vs 3.3%), Q-wave myocardial infarction (0% vs 2.2%), non-Q wave myocardial infarction (3.4% vs 6.6%), bypass surgery (0% vs 0%) and repeat angioplasty (6.9% vs 1.1%). Quantitative angiography showed significant improvements in minimal lumen diameter (mean 2.17 vs 3.16 mm, p < 0.001) and percentage diameter stenosis (mean 31% vs 13%, p < 0.001) in the new device group after the procedures. The minimum lumen diameter remained larger at 3 (p < 0.001) and 6 months (p < 0.05) in the new device group. Therefore, angiographic restenosis rate was higher in the balloon group (55% vs 21%, p < 0.005). Five-year survival rate showed no significant difference between the groups (75.0% vs 83.8%). CONCLUSIONS: New devices significantly improved the minimal lumen diameter after angioplasty for unprotected left main trunk disease, and lead to significant improvement of restenosis rate at follow-up.

Aged↗

A novel cytoplasmic GTPase XAB1 interacts with DNA repair protein XPA.

The xeroderma pigmentosum group A protein (XPA) plays a central role in nucleotide excision repair (NER). To identify proteins that bind to XPA, we screened a HeLa cDNA library using the yeast two-hybrid system. Here we report a novel cytoplasmic GTP-binding protein, designated XPA binding protein 1 (XAB1). The deduced amino acid sequence of XAB1 consisted of 374 residues with a molecular weight of 41 kDa and an isoelectric point of 4.65. Sequence analysis revealed that XAB1 has four sequence motifs G1-G4 of the GTP-binding protein family in the N-terminal half. XAB1 also contains an acidic region in the C-terminal portion. Northern blot analysis showed that XAB1 mRNA is expressed ubiquitously, and immunofluorescence analysis revealed that XAB1 is localized mainly in the cytoplasm. Consistent with the GTP-binding motif, purified recombinant XAB1 protein has intrinsic GTPase activity. Using the yeast two-hybrid system, we elucidated that XAB1 binds to the N-terminal region of XPA. The deletion of five amino acids, residues 30-34 of XPA, required for nuclear localization of XPA abolished the interaction with XAB1. These results suggest that XAB1 is a novel cytoplasmic GTPase involved in nuclear localization of XPA.

Adenosine Triphosphatases↗

Dialysis-related spinal canal stenosis: a clinicopathological study on amyloid deposition and its AGE modification.

Three cases operated for spinal canal stenosis induced by dialysis-related amyloidosis (DRA) were investigated clinicopathologically. Cases were all-male, and had undergone hemodialysis around 20 years. In two cases, cervical plain X-rays showed only minor spondylotic changes. However, magnetic resonance imaging (MRI), myelography, and computed tomography (CT) showed extradural thickness with compression on the cervical spinal cord and cauda equina. In one case cervical X-rays showed typical destructive spondyloarthropathy (DSA), and MRI showed compression myelopathy. Surgical treatment on both cervical and lumbar spine in two cases and on cervical spine only in one case successfully reduced the symptoms. Extradural thickened tissue and ligament flavum obtained during surgery were studied histopathologically and immunostained by using anti-CD68, anti-beta2-microglobulin (beta2m), and anti-advanced glycation end product (AGE) antibody. Congo red stain showed diffuse or nodular amyloid deposition, and immunostaining with anti-beta2m and anti-AGE antibodies also demonstrated the same distribution pattern. Thus, beta2m-positive amyloid tissue in the extradural thickness (extradural amyloid deposition) was immunohistochemically demonstrated to be modified with AGE. Inflammatory reaction with histiocytic and giant cell infiltration was also shown around the amyloid tissues. There were CD68-positive cells, and some cells were positive for AGE and beta2m. These findings suggest that beta2m accumulation and inflammatory reaction finally promote destruction of connective tissues. MRI, CT and/or myelography are necessary for diagnosing spinal canal stenosis accompanied by DRA. In conclusion, we propose a more comprehensive concept of dialysis-related spinal canal stenosis, which includes both DSA and myeloradiculopathy induced by extradural thickness.

Amyloid↗