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Biomedical subjects

H Tamai

Publications and source records attributed to H Tamai.

At least 55 records · Page 3Linked to original sources
PubMed2000

Initial and 6-month results of biodegradable poly-l-lactic acid coronary stents in humans.

BACKGROUND: Although metallic stents are effective in preventing acute occlusion and reducing late restenosis after coronary angioplasty, many concerns still remain. Compared with metallic stents, poly-l-lactic acid (PLLA) stents are biodegradable and can deliver drugs locally. The aim of this study was to evaluate the feasibility, safety, and efficacy of the PLLA stent. METHODS AND RESULTS: Fifteen patients electively underwent PLLA Igaki-Tamai stent implantation for coronary artery stenoses. The Igaki-Tamai stent is made of a PLLA monopolymer, has a thickness of 0.17 mm, and has a zigzag helical coil pattern. A balloon-expandable covered sheath system was used, and the stent expanded by itself to its original size with an adequate temperature. A total of 25 stents were successfully implanted in 19 lesions in 15 patients, and angiographic success was achieved in all procedures. No stent thrombosis and no major cardiac event occurred within 30 days. Coronary angiography and intravascular ultrasound were serially performed 1 day, 3 months, and 6 months after the procedure. Angiographically, both the restenosis rate and target lesion revascularization rate per lesion were 10.5%; the rates per patient were 6.7% at 6 months. Intravascular ultrasound findings revealed no significant stent recoil at 1 day, and they revealed stent expansion at follow-up. No major cardiac event, except for repeat angioplasty, developed within 6 months. CONCLUSIONS: Our preliminary experience suggests that coronary PLLA biodegradable stents are feasible, safe, and effective in humans. Long-term follow-up with more patients will be required to validate the long-term efficacy of PLLA stents.

Adult↗
PubMed2000

Angiographic and clinical outcome of a new self-expanding intracoronary stent (RADIUS): results from multicenter experience in Japan.

The RADIUS coronary stent featuring a multisegmented slotted tube design and self-expanding nitinol delivery system has a high radial force and flexibility, uniform expansion, and contours to the shape of the vessel. Successful stent deployment was achieved in 104 stable angina patients (106 lesions; 44% LAD, 19% circumflex, and 37% RCA). Mean minimal lumen diameter (MLD) increased from 0.77 +/- 0.46 mm to 2.88 +/- 0.61 mm and mean percent diameter stenosis (% DS) decreased from 73 +/- 14% to 6 +/- 13% immediately after the procedure. At 6-month follow-up, two patients (2%) underwent urgent target revascularization, and cerebral bleeding occurred in one patient (1%). Angiographic follow-up was performed in 94 lesions (89%) and mean MLD and mean % DS were 2.08 +/- 0.92 mm and 30% +/- 24%, respectively. Stent restenosis (>50% diameter stenosis at follow-up) was observed in 16 (17%) of all lesions. The high success rate for stent deployment, low incidence of major adverse cardiac event, and lower restenosis rate after stent implantation indicate that the RADIUS stent is useful for coronary intervention.

Adult↗
PubMed2000

Three-dimensional magnetic resonance angiography of vascular lesions in children.

We applied three-dimensional (3D) magnetic resonance (MR) angiography to vascular lesions in children and evaluated the clinical usefulness of this technique. Ten patients, whose ages ranged from 1 month to 16 years, underwent 3D MR angiography for 12 vascular lesions, including lesions in seven pulmonary arteries, two thoracic aortae, a pair of renal arteries, and one iliac artery. Three-dimensional MR angiography was performed with body-or pelvic-phased array coils on a 1.5-T scanner using fast spoiled gradient echo sequence. Data were acquired with the following parameters: TE, 1.9 ms; TR, 10.1 ms; flip angle, 20-60 degrees ; 1 or 2 NEX; field of view, 24-48 x 18-40 cm; matrix, 256 or 512 x 128 or 256; slice thickness, 1.2-7.5 mm; and 12, 28, or 60 partitions. Vascular imaging was enhanced with 20% gadolinium-diethylenetriaminepentaacetic acid. The examination was performed under breath-holding in six patients and with shallow breathing in four patients. In a comparative study with other noninvasive methods, 3D MR angiography was superior in seven of nine cases to other noninvasive examinations and in two cases, all methods evaluated the lesions. Furthermore, six cases were compared with conventional angiography. In five of the six cases, both methods depicted the lesions similarly, and in one case, MR angiography was more effective. A quantitative comparison of vascular diameter in the MR image was made with that in the conventional angiographic image. The correlation between them was excellent: y = 1.145x-2.090 (r = 0.987; P < 0.0001), where x is the diameter in the conventional angiographic images, y is the diameter in the MR images, and r is the correlation coefficient. In conclusion, 3D MR angiography is useful for depicting peripheral vascular lesions in children.

Adolescent↗
PubMed2000

Pachymeningitis with pseudo-Foster Kennedy syndrome.

PURPOSE: To report a case of pachymeningitis with pseudo-Foster Kennedy syndrome in a patient who was positive for perinuclear antineutrophil cytoplasmic antibody. METHODS: Case report. A 44-year-old man was examined for headache and diplopia. RESULTS: Left eye showed limitation of abduction. Ocular fundus, computed tomography (CT), and magnetic resonance imaging (MRI) of the head and orbits were normal. The diplopia subsided spontaneously. Six months later, he noticed sudden visual loss in the left eye. The left eye showed optic disk atrophy and episcleritis, and the right eye showed papilloedema. Computed tomography and MRI exhibited thickened dura mater. Serum perinuclear antineutrophil cytoplasmic antibody level was highly increased. CONCLUSION: Pachymeningitis with ocular involvement sometimes requires repeated CT or MRI for diagnosis. This disorder may be caused by microvasculitis.

Adult↗
PubMed2000

Changes in CD4+CD8-/CD4-CD8+ ratio and humoral immune functions in vitamin B12-deficient rats.

To clarify the role of vitamin B12 in the function of cell-mediated and humoral immune functions, the splenocytes expression of CD4, CD8 and serum C3, IgM, IgG concentrations were examined in vitamin B12-deficient rats, and the effect of the administration of methylcobalamin was also studied. The CD4+CD8-/CD4-CD8+ ratio in splenocytes was significantly higher in vitamin B12-deficient rats than in control rats (p < 0.05). The value in the 48 hours after methylcobalamin administration group, was within the normal range (p < 0.05). From these results, the elevation of the CD4+CD8-/CD4-CD8+ ratio by vitamin B12-deficiency was confirmed in rats. The serum C3, IgM and IgG concentrations were lower in the vitamin B12-deficient group than in the control group. These findings suggest that vitamin B12 plays a role in maintaining the immune function in rats.

Animals↗
PubMed2000

A novel mutation (296 del G) of the SOX90 gene in a patient with campomelic syndrome and sex reversal.

The human SOX9 gene is responsible for the campomelic syndrome (CMPS) and sex reversal. This gene encodes a transcription factor containing a DNA binding domain homologous to the SRY high mobility group (HMG) domain. A novel mutation of SOX9, i.e. a single G deletion in one allele at nt 296 from A of the first ATG in the open reading frame, was identified in a patient with CMPS with sex reversal. The deletion resulted in a frameshift mutation upstream of the HMG box and a stop codon 30 bp downstream of the HMG box. The predicted truncated SOX9 protein contained 108 amino acids instead of the 509 amino acids of the normal SOX9 protein, removing nearly 80% of the SOX9 protein, including the HMG and the C-terminal transactivation domain. Most patients with CMPS reported previously died within the neonatal period. Our findings that the patient has survived, although has been in daily need of mechanical ventilation support for 5 years and 3 months despite a severely impaired SOX9 protein, do not support a linear relationship between the type of mutation and severity of the clinical outcome.

Abnormalities, Multiple↗
PubMed2000

Critical value for the index of body fat distribution based on waist and hip circumferences and stature in obese girls.

OBJECTIVE: To determine the critical value for the standard deviation score (SDS) of waist-hip ratio (WHR)/height (Ht), as an age-adjusted measure of body fat distribution, in relation to occurrence of biochemical complications in obese girls. DESIGN: Cross-sectional, clinical study. The (WHR/Ht)-SDS was calculated as described previously. Obese girls were classified into two groups according to the occurrence of abnormal values in either serum triglyceride, alanine aminotransferase or insulin level. The criteria for obesity were subjected to the receiver operating characteristic (ROC) analysis. SUBJECTS: One-hundred and twenty-four outpatient Japanese obese girls, ranging in age from 9 to 15 y. MEASUREMENTS: Height, body weight, waist girth and hip girth as anthropometric measures. Percentage overweight, waist girth, WHR and (WHR/Ht)-SDS as criteria for obesity. Clinical laboratory analysis for fasting blood samples of obese children. RESULTS: Fifty-nine girls were classified into the no complication group, and 65 girls into the complication group. Those with complications were older, more obese, and their waist girth and WHR were larger, than the girls without complications. The (WHR/Ht)-SDS was >2-fold higher and lipoprotein profile was more atherogenic in the complication group than in the no complication group. Among the four criteria of obesity, (WHR/Ht)-SDS gave the ROC curve skewed furthest into the top left corner of the diagram. Both sensitivity and specificity for (WHR/Ht)-SDS were >80% at the critical value of 2.00. The sensitivity for waist girth was as high as that for specificity for the rest of the criteria were <80%. CONCLUSION: Only (WHR/Ht)-SDS showed high enough sensitivity and specificity to predict metabolic derangement in the present obese girls. (WHR/Ht)-SDS can serve as the diagnostic criterion that classifies obesity in Japanese adolescent girls into two types.

Adipose Tissue↗
PubMed2000

Psychosocial factors affecting psychosomatic symptoms in Japanese schoolchildren.

BACKGROUND: In a previous study we reported the prevalence of psychosomatic symptoms in 1619 Osaka elementary schoolchildren using our original general health questionnaire assessed by their parents. We found that psychosomatic symptoms were increasing with age. This study was designed to investigate psychosocial factors responsible for increasing psychosomatic symptoms with age. METHODS: We calculated a correlation coefficient between the physical complaints score (PCS) and these psychosocial variables using quantitation I of multiple regression analysis separately in the older (10-12 years, n = 860) and the younger age group (7-9 years, n = 759). RESULTS: A stronger relationship between PCS and psychosocial problems was found in the older (r = 0.719, P < 0.0001) than in the younger age group (r = 0.570, P < 0.0001). Further analysis demonstrated that difficulties in school performance and increasing psychological conflicts with human relationships were major causes of somatic complaints in the older age group. In the younger age group, however, immaturity of social skills seems to be a primary problem. In addition, poor parental interaction and the playing of computer games were found to increase somatic complaints in children. CONCLUSION: Children in the older age reflect the closer bio-psycho-socio interaction compared with their younger counterparts. This may give rise to a high incidence of psychosomatic disorders and school refusal in Japanese children. We emphasize that psychological support by parents in daily life is necessary to reduce psychosomatic symptoms in children.

Age Factors↗
PubMed2000

KL-6, a mucinous glycoprotein, as an indicator of chronic lung disease of the newborn.

KL-6 is a mucinous glycoprotein that is preferentially expressed by alveolar type 2 cells. Plasma KL-6 was higher in infants with chronic lung disease (n = 12) than in infants without chronic lung disease (n = 14) on day 0-1, 10, and 30 (P =.04). KL-6 correlated with the alveolar-arterial oxygen tension difference on day 10 and day 30. Plasma KL-6 may be useful as an early marker of chronic lung disease and an indicator of severity.

Antigens↗
PubMed2000

Blood pressure and cardiovascular autonomic function in healthy children and adolescents.

OBJECTIVES: To investigate the relationship between blood pressure levels and cardiovascular autonomic function in adolescents and preadolescents. STUDY DESIGN: We measured variability of beat-to-beat arterial pressure and R-R intervals using power spectral analysis in 56 adolescents (aged 13-16 years; mean age, 9.0 +/- 1.4 years) and 71 preadolescents (6-12 years; mean age, 13.5 +/- 1.1 years) in the supine and standing positions. RESULTS: Adolescents had higher levels of systolic arterial pressure and lower high-frequency power of RR intervals than preadolescents. Correlation between the basal level of arterial pressure and autonomic function was observed in adolescents but not in preadolescents. In adolescents, multivariate analysis indicated that the basal level of arterial pressure was inversely related with the high-frequency power of RR intervals and positively with the ratio of low-frequency and high-frequency power. No significant relation was found in preadolescents. During standing, adolescents had a more marked increase in diastolic arterial pressure, heart rate, low frequency of R-R intervals, and low frequency of arterial pressure compared with those of preadolescents. Changes in diastolic pressure showed a significant negative correlation with changes in high frequency of R-R intervals. CONCLUSION: Cardiovascular autonomic function plays an important role in increasing blood pressure levels associated with increased modulation of vagal tone of the heart after puberty but does not in the preadolescent.

Adolescent↗
PubMed2000

Mechanism of alpha-tocopheryl succinate-induced apoptosis of promyelocytic leukemia cells.

Selective induction of apoptosis in tumor cells is important for treating patients with cancer. Because oxidative stress plays an important role in the process of apoptosis, we studied the effect of alpha-tocopheryl succinate (VES) on the fate of cultured human promyelocytic leukemia cells (HL-60). The presence of fairly low concentrations of VES inhibited the growth and DNA synthesis of HL-60 cells, and also induced their apoptosis via a mechanism that was inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), an inhibitor of pan-caspases. VES activated various types of caspases, including caspase-3, 6, 8, and 9, but not caspase-1. VES triggered the reaction leading to the cleavage of Bid, a member of the death agonist Bcl-2 family, and released cytochrome c (Cyt.c) from the mitochondria into the cytosol by a z-VAD-fmk-inhibitable mechanism. VES transiently increased the intracellular calcium level [Ca2+]i and stimulated the release of Cyt.c in the presence of inorganic phosphate (Pi). However, high concentrations of VES (approximately 100 microM) hardly induced swelling of isolated mitochondria but depolarized the mitochondrial membrane potential by a cyclosporin A (CsA)-insensitive mechanism. These results indicate that VES-induced apoptosis of HL-60 cells might be caused by activation of the caspase cascade coupled with modulation of mitochondrial membrane function.

Amino Acid Chloromethyl Ketones↗
PubMed2000

Beta-carotene 15,15'-dioxygenase activity in streptozotocin-induced diabetic rats.

We measured retinol levels and beta-carotene 15,15'-dioxygenase activity in rats with streptozotocin-induced diabetes mellitus to assess the relationship between the disease and the conversion of beta-carotene to retinol. The plasma retinol level was significantly lower in diabetic rats than in control rats, but the hepatic retinol level was significantly higher than the control. The hepatic dioxygenase activity, but not that of the intestinal mucosa, was significantly lower in diabetic rats than in control rats. The hepatic dioxygenase activity showed a significant negative correlation with the hepatic retinol levels. The results suggest the disturbed secretion of retinol from the liver and suppression of hepatic dioxygenase activity by the retinol increased in the liver in diabetic rats.

Animals↗
PubMed2000

Effect of acute ethanol administration on the intestinal absorption of endotoxin in rats.

BACKGROUND: Endotoxin has been implicated in the pathogenesis and progression of alcoholic liver disease. Not only inactivation of reticuloendothelial function, which reduces clearance of endotoxin, but also an increase in absorption of endotoxin from the intestine may be involved in mechanisms of ethanol-induced endotoxemia. However, it is unclear how ethanol affects absorption of endotoxin from the intestine in vivo. METHODS: We gave 10 mg/kg of lipopolysaccharides to rats with water (group 1), 5% ethanol (group 2), or 20% ethanol (group 3) using an intubation tube to the stomach. Blood samples were collected and plasma endotoxin levels were measured. We used fluorescence spectrophotometer to examine permeability of the gut to macromolecules (fluorescein isothiocyanate-dextran; 4,000 Da [FD4] or 20,000 Da [FD20]). RESULTS: Plasma endotoxin levels were not different between group 1 (9 +/- 2 pg/ml) and group 2 (14 +/-3 pg/ml), whereas they significantly increased in group 3 with a peak at 60 min (87 +/- 35 pg/ml). Acute ethanol administration did not affect clearance of endotoxin in rats. Hemorrhagic erosions of the proximal small intestine with epithelial cell loss were observed in group 3 at 4 hr, but no significant histological change was observed at 30 min by light microscopy. Acute ethanol administration (20%) increased the permeability of the small intestine to FD4 and FD20 in 30 min when no hemorrhagic erosions of the proximal small intestine with epithelial cell loss were observed. CONCLUSIONS: Acute ethanol administration increases intestinal permeability before pathological changes are revealed by light microscopy. Acute ethanol ingestion, especially at high concentrations, facilitates the absorption of endotoxin from rats' small intestine via an increase in intestinal permeability, which may play an important role in endotoxemia observed in alcoholic liver injury.

Animals↗
PubMed2000

Comparison of cyanamide and disulfiram in effects on liver function.

BACKGROUND: Cyanamide, an aversive drug widely used in Japan, develops ground-glass inclusion bodies in the hepatocytes at high incidences, which may be associated with portal inflammation and fibrosis. When cyanamide-treated alcoholics relapse drinking, the combined effect of cyanamide and alcohol produce more severe portal inflammation along with the emergence of ground-glass inclusions. Disulfiram also causes hepatitis, but there have been no comparative studies of effects of cyanamide and disulfiram on liver function. METHODS: We reviewed the laboratory data of 408 alcoholics admitted for a 3 month course of alcohol detoxification and rehabilitation. Patients tested negative for hepatitis virus markers and were diagnosed as not having cirrhosis. Among the subjects, 222 patients received cyanamide treatment (a daily dose of 70 mg) without a history of disulfiram treatment, and 186 received disulfiram (a daily dose of 200 mg) without a history of cyanamide treatment. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels obtained at 0, 4, 8, and 12 weeks of administration of each aversive drug were compared between the two alcoholic groups. RESULTS: Elevation of serum transaminases (AST > ALT) probably due to alcoholic liver disease quickly fell after abstinence. In patients who took cyanamide, the ALT levels were significantly higher at 4 and 12 weeks than in those who took disulfiram. Re-elevations of ALT after alcohol detoxification were more frequently observed in those who took cyanamide than in those who took disulfiram (19.4% vs. 5.9%, p < 0.001). The re-elevations of ALT were slight to moderate, being more than 3-fold in three (1.4%) patients who took cyanamide and four (2.2%) who took disulfiram. The re-elevations occurred more frequently in those with a history of cyanamide treatment before the present treatment than in those who took cyanamide for the first time (31.1% vs. 16.4%, p < 0.05). CONCLUSIONS: Cyanamide, compared with disulfiram, was more frequently associated with elevations of ALT that persisted after abstinence.

Adult↗