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Biomedical subjects

H Nakano

Publications and source records attributed to H Nakano.

At least 325 records · Page 18Linked to original sources
PubMed1999

Prevention of reactive oxygen-induced endothelial cell injury by blocking its process.

Endothelial cell (EC) injury induced by reactive oxygen species (ROS) was investigated and effects of Ca(2+) channel blockers, agents which elevate intracellular cAMP levels ([cAMP](i)), and protein kinase inhibitors on H(2)O(2)-induced EC injury were analyzed using human umbilical vein EC cultures. Exposure to H(2)O(2) increased intracellular Ca(2+) levels and decreased [cAMP](i). Ca(2+) channel blockers, [cAMP](i)-elevating agents, and protein kinase inhibitors significantly inhibited H(2)O(2)-induced EC injury. Data suggest that H(2)O(2)-induced EC injury is mediated by extracellular Ca(2+) influx, intracellular cAMP efflux, and intracellular signaling, each of which is blocked by Ca(2+) channel blockers, [cAMP](i)-elevating agents, or protein kinase inhibitors. It is suggested that ischemia/reperfusion injury induced by ROS may be prevented by Ca(2+) channel blockers, [cAMP](i)-elevating agents, and protein kinase inhibitors.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Depression of peripheral chemosensitivity by a dopaminergic mechanism in patients with obstructive sleep apnoea syndrome.

In the present study, respiratory drives to chemical stimuli and peripheral chemosensitivity were evaluated in patients with obstructive sleep apnoea (OSAS). The effects of oral administration of domperidone, a selective dopamine D2-receptor antagonist, were also examined, to study the respiratory effects of endogenous dopamine on peripheral chemoreceptors. Sixteen patients with OSAS and nine normal control subjects were studied. Respiratory responses to hypercapnia and hypoxia were measured using the rebreathing method and isocapnic progressive hypoxia method, respectively. The hypoxic withdrawal test, which measures the decrease in ventilation caused by two breaths of 100% O2 under mild hypercapnic hypoxic conditions (end-tidal oxygen and carbon dioxide tensions approximately 8.0 kPa and 5.3-6.7 kPa, respectively), was used to evaluate peripheral chemosensitivity. In the patients with OSAS, ventilatory responses to hypercapnia and hypoxia were significantly decreased compared with those of control subjects. Hypoxic withdrawal tests showed that peripheral chemosensitivity was significantly lower in patients with OSAS than in normal subjects. Hypercapnic ventilatory response and peripheral chemosensitivity were enhanced by administration of domperidone in the patients with OSAS, although no changes in either of these were observed in the control subjects. The hypoxic ventilatory response and peripheral chemosensitivity in the patients with OSAS were each significantly correlated with severity of hypoxia during sleep. These findings suggest that peripheral chemosensitivity in patients with obstructive sleep apnoea syndrome may be decreased as a result of abnormality in dopaminergic mechanisms and that the reduced chemosensitivity observed in patients with obstructive sleep apnoea syndrome may affect the severity of hypoxia during sleep.

Adult↗
PubMed1999

Role of neutrophil elastase in ozone-induced airway responses in guinea-pigs.

Ozone-induced airway hyperresponsiveness occurs concurrently with neutrophilic inflammation and epithelial injury in various species including humans. The mechanism of neutrophil-induced airway hyperresponsiveness, however, has not yet been fully clarified. Neutrophil elastase (NE) is a multipotent protease released from activated neutrophils, which may play a role in ozone-induced airway hyperresponsiveness. In order to address this issue, the effects of ONO-5046, a specific NE inhibitor, were investigated in ozone-exposed guinea-pigs. Awake animals were exposed to ozone at 3 parts per million for 2 h, airway responsiveness to acetylcholine (ACh) measured and examination of bronchoalveolar lavage fluid (BALF) performed. Ozone exposure increased airway responsiveness to both inhaled and intravenous ACh, the concentration of NE in BALF and the number of neutrophils and airway epithelial cells in BALF. Although pretreatment with ONO-5046 (200 mg x kg(-1), i.p.) had no effect on these changes immediately after the exposure, it significantly inhibited airway hyperresponsiveness to inhaled ACh, whilst decreasing the number of neutrophils and epithelial cells in BALF 3-5 h after the exposure. In contrast, ONO-5046 showed no significant effect on airway hyperresponsiveness to intravenous ACh at any time. These results suggest that neutrophil elastase contributes to ozone-induced airway hyperresponsiveness developing during the hours after exposure, presumably by means of inducing epithelial injury.

Acetylcholine↗
PubMed1999

Interaction of radicicol with members of the heat shock protein 90 family of molecular chaperones.

The Hsp90 family of proteins in mammalian cells consists of Hsp90 alpha and beta, Grp94, and Trap-1 (Hsp75). Radicicol, an antifungal antibiotic that inhibits various signal transduction proteins such as v-src, ras, Raf-1, and mos, was found to bind to Hsp90, thus making it the prototype of a second class of Hsp90 inhibitors, distinct from the chemically unrelated benzoquinone ansamycins. We have used two novel methods to immobilize radicicol, allowing for detailed analyses of drug-protein interactions. Using these two approaches, we have studied binding of the drug to N-terminal Hsp90 point mutants expressed by in vitro translation. The results point to important drug contacts with amino acids inside the N-terminal ATP/ADP-binding pocket region and show subtle differences when compared with geldanamycin binding. Radicicol binds more strongly to Hsp90 than to Grp94, the Hsp90 homolog that resides in the endoplasmic reticulum. In contrast to Hsp90, binding of radicicol to Grp94 requires both the N-terminal ATP/ADP-binding domain as well as the adjacent negatively charged region. Radicicol also specifically binds to yeast Hsp90, Escherichia coli HtpG, and a newly described tumor necrosis factor receptor-interacting protein, Trap-1, with greater homology to bacterial HtpG than to Hsp90. Thus, the radicicol-binding site appears to be specific to and is conserved in all members of the Hsp90 family of molecular chaperones from bacteria to mammals, but is not present in other molecular chaperones with nucleotide-binding domains.

3T3 Cells↗
PubMed1999

Synthesis of benzimidazole derivatives as antiallergic agents with 5-lipoxygenase inhibiting action.

Syntheses were conducted of novel benzimidazole derivatives that suppress histamine release from mast cells, inhibit 5-lipoxygenase, and possess antioxidative action. Among the compounds synthesized, 1-[2-[2-(4-hydroxy- 2,3,5-trimethylphenoxy)ethoxy]ethyl]-2-(4-methyl-1- homopiperazino)benzimidazole (22) potently suppressed histamine release from rat peritoneal mast cells triggered by the antigen-antibody reaction, inhibited 5-lipoxygenase in rat basophilic leukemia-1 (RBL-1) cells, and prevented the NADPH-dependent lipid peroxidation induced by Fe(3+)-ADP in rat liver microsomes, in addition to an antagonizing the contraction of guinea pig ileum caused by histamine.

Animals↗
PubMed1999

Enzymatic synthesis of N-acetylglucosaminyl-cyclodextrin by the reverse reaction of N-acetylhexosaminidase from jack bean.

Novel heterobranched cyclodextrins (CDs), N-acetylglucosaminyl-cyclodextrins (GlcNAc-CD), were synthesized from a mixture of GlcNAc and alpha, beta, or gamma CD by the reverse reaction of N-acetylhexosaminidase from jack bean. Optimum pH and temperature for the production of GlcNAc-alpha CD by N-acetylhexosaminidase were pH 4.9 and 50-70 degrees C, respectively. The maximum yield of GlcNAc-alpha CD was 17.5% (mol/mol) at the concentration of 1 M GlcNAc and 0.25 M alpha CD. The reverse reaction product, GlcNAc-alpha CD, was separated into two peaks by HPLC analysis on the ODS column. Their structures were identified as 6-O-beta-D-N-acetylglucosaminyl-alpha CD and 2-O-beta-D-N-acetylglucosaminyl-alpha CD by FAB-MS and NMR spectroscopies. N-Acetylhexosaminidase from jack bean also synthesized N-acetylgalactosaminyl-alpha CD from N-acetylgalactosamine and alpha CD.

Chromatography↗
PubMed1999

Effect of age on urinary excretion of N-acetyl-beta-D-glucosaminidase.

To examine the relationship between the concentrations of urinary NAG and age, we measured ratios of urinary N-acetyl-beta-D-glucosaminidase (NAG) to urinary creatinine (NAG index) in 137 healthy subjects, aged from 19 to 88 years. The study is also designed to evaluate the relationship between urinary NAG and blood pressure. The subjects were divided into 7 subgroups, according to their age (< 30, 30-39, 40-49, 50-59, 60-69, 70-79, 80 or more years). There was a positive correlation between NAG index and age (r = 0.36; P < 0.001). The regression equation relating NAG index (y) to age (x) was y = 0.065x + 0.97. The mean NAG indexes for the 7 subgroups divided by age were significantly different (P < 0.01). There was a positive correlation between NAG index and systolic blood pressure (r = 0.18; P < 0.05), but was not between diastolic blood pressure and NAG index. In multiple regression analysis, age and BUN significantly correlated with NAG index (r = 0.32; P < 0.01, r = 3.3; P = 0.07, respectively), although there was no correlation between systolic blood pressure and NAG index. This cross-sectional study showed a clear elevation in NAG index with age. The rate of elevation was 0.65 per decade. Urinary excretion of NAG may be unrelated to blood pressure.

Acetylglucosaminidase↗
PubMed1999

Perioperative hepatic functional risk assessed with technetium-99m diethylenetriamine pentaacetic acid-galactosyl human serum albumin liver scintigraphy in patients undergoing pancreaticoduodenectomy complicated by obstructive jaundice.

CONCLUSION: Liver scintigraphy with technetium-99m diethylenetriamine pentaacetic acid-galactosyl human serum albumin (Tc-GSA) can be used to predict outcome of biliary drainage and hepatic function after pancreaticoduodenectomy in patients with pancreatic, biliary, and ampullary carcinomas complicated by obstructive jaundice. BACKGROUND: Preoperative obstructive jaundice has been reported as a crucial risk factor for serious postoperative complications in patients undergoing pancreaticoduodenectomy. The aim of the present study was to investigate whether Tc-GSA liver scintigraphy can assess hepatic functional risk in patients with pancreatic, biliary, and ampullary carcinomas complicated by obstructive jaundice. METHODS: Liver scintigraphy was performed before biliary drainage in 18 patients with obstructive jaundice. The maximum removal rate of Tc-GSA (GSA-Rmax; standard normal value > or = 0.60) was calculated. These patients underwent pancreaticoduodenectomy with wide lymphadenectomy. The efficacy of preoperative biliary drainage was assessed with the decrease in serum bilirubin concentration in the first week after biliary drainage. Postoperative liver function was assessed with the increase in serum bilirubin concentration, which was the difference between the immediate preoperative and maximal postoperative bilirubin concentrations. RESULTS: Serum bilirubin decreased more in the first week after biliary drainage in patients with GSA-Rmax > or = 0.60 (7.64 +/- 1.09 mg/Dl/wk) than in patients with GSA-Rmax < 0.60 (3.56 +/- 1.25 mg/DL/wk, p = 0.042). Postoperative bilirubin increased less in patients with GSA-Rmax > or = 0.60 (0.81 +/- 0.30 mg/dL) than in patients with GSA-Rmax < 0.60 (4.00 +/- 0.69 mg/DL, p = 0.0012). Multivariate analysis showed that GSA-Rmax significantly predicted the postoperative bilirubin increase (p = 0.020).

Adult↗
PubMed1999

[Spontaneous extradural spinal hematoma. Case report].

We report a case of a 55-year-old woman, that has a mild hypertension, in use of a betablocker drugs, who had a sudden spinal cord compression syndrome with intense cervical pain, tetraplegia and sensitivity level in C4. Extradural spinal hematoma of the cervical spine was diagnosed by magnetic resonance. The patient underwent a laminectomy and aspiration of the hematoma. The patient is on physiotherapy and presents progressive motor and sensitivity improvement.

Decompression, Surgical↗
PubMed1999

Intrabronchial Aspergillus nidulans infection in an immunocompetent man.

We describe the first report of intrabronchial Aspergillus nidulans infection in an immunocompetent patient, which fit the description of bronchocentric granulomatosis. The patient had a history of accidental aspiration of light grade oil. Fiberoptic bronchoscopy revealed that the right B4aii alpha was obstructed. Endobronchial biopsy specimens contained fungal hyphae. The fungus was confirmed to be Aspergillus nidulans by culture. We suspected that aspiration of light grade oil had injured the bronchial mucosa, after which airborne Aspergillus nidulans had entered the lesion and multiplied. Intrabronchial fungal infection can occur in a healthy person without immunologic abnormalities, if a bronchial lesion provides an entry portal.

Aspergillosis↗
PubMed1999

Changes in coagulation factors and fibrinolytic components of postmenopausal women receiving continuous hormone replacement therapy.

OBJECTIVE: The effect of hormone replacement therapy (HRT) on coagulation factors and fibrinolytic components in postmenopausal women was studied for 6 months to elucidate whether continuous HRT has an influence on thrombosis. METHODS: One hundred and thirty-four postmenopausal women were divided into three groups according to treatment: 39 women who had undergone hysterectomy and oophorectomy received 0.625 mg/day of conjugated equine estrogen (CEE) continuously (CEE therapy), 48 postmenopausal women received both 0.625 mg/day of CEE and 2.5 mg/day of medroxyprogesterone acetate (MPA) continuously (CEE/MPA therapy) and 47 postmenopausal women received placebo as control. The following variables were measured before treatment as well as after 1, 3 and 6 months of treatment: factor VII activity, protein C activity, fibrinogen level, antithrombin III activity, plasminogen activator inhibitor-1 (PAI-1) level and the plasma concentration of tissue-type plasminogen activator (t-PA). RESULTS: After 1 month of treatment, protein C activity increased by 9.6% and 11.4% of the initial value (p < 0.05), fibrinogen level decreased by 7.8% and 6.1% of the initial value (p < 0.05) and PAI-1 decreased by 19.4% and 14.3% of the initial value (p < 0.05) in the CEE therapy group and the CEE/MPA therapy group, respectively. Factor VII activity increased by 10.1% of the initial value (p < 0.05) in the CEE therapy group only. Antithrombin III and t-PA levels did not change throughout either treatment. CONCLUSION: Except for an increase in factor VII activity in the case of continuous CEE therapy, continuous HRT had no unfavorable effects on either coagulation factors or fibrinolytic components.

Antithrombin III↗
PubMed1999

[An elderly case of giant infected liver cyst that decreased dramatically without percutaneous aspiration].

A 70-year-old woman was referred to our hospital for treatment of cholelithiasis. A giant liver cyst (6 cm in diameter) had been diagnosed three years earlier. On admission, she had low grade fever and hepatomegaly. High values were observed for WBC (9900/microliter), CRP (8.9 mg/dl), GPT (45 IU/l), ALP (1399 IU/l), gamma-GTP (333 IU/l) and LAP (249 IU/l). The diagnosis of infected liver cyst (8 cm in diameter) was made based on contrast-enhanced CT scan. Endoscopic retrograde cholangiopancreaticography showed no communication between the cyst and the intrahepatic bile duct. She was successfully managed with antibiotics and discharged without percutaneous aspiration the cyst. On abdominal CT scan 4 months after the discharge, the liver cyst had decreased dramatically in size (1 cm in diameter). The patient remains healthy without symptoms.

Aged↗
PubMed1999

[Sulfonylureas and daily blood glucose profiles in elderly diabetics].

The aim of this study is to clarify the relationship between the efficacy of sulfonylureas and duration of diabetes in elderly diabetics. Daily blood glucose profiles were measured in 87 Type 2 elderly diabetic patients on sulfonylureas (tolbutamide, gliclazide or glibenclamide). Plasma glucose concentrations were determined at 08.00 (before breakfast), 10.00, 12.00 (before lunch), 14.00, 18.00 (before dinner), 20.00, 24.00, 03.00, 06.00, 08.00 hours. The subjects were divided into 4 sub-groups, according to their duration of the diabetes (< 10, 10-14, 15-19, 20 or more years). Mean plasma glucose values at 08.00, 10.00, 20.00, 03.00 and 06.00 hours were not significantly different among the four groups. However, mean plasma glucose values at 12.00, 14.00, 18.00, 00.00 hours and mean total blood glucose area under the daily profile (total BG) were significantly different among the four groups and the values in patients with a history of diabetes of 15 years or more increased. Duration of diabetes positively correlated with blood glucose values at 12.00, 14.00, 18.00, 00.00, 03.00 hours and total BG, and the dose of sulfonylureas positively correlated with blood glucose values at 12.00, 14.00, 18.00, 00.00 hours and total BG in multiple regression analysis. These results suggest that duration of diabetes and dose of sulfonylureas are important determinants of blood glucose control with sulfonylureas in elderly diabetic patients.

Aged↗
PubMed1999

[Effect of age, gender, and body fat distribution on serum leptin concentrations].

The aim of this study was to clarify the relationship between serum leptin concentration and age, gender and body fat distribution. Serum leptin concentrations were determined 267 subjects (138 men and 129 women), aged 30 to 91. The thicknesses of the preperitoneal fat layer (Pmax) and subcutaneous fat layer (Smin) in the abdomen were measured by ultrasonography. Fat mass and percent fat were measured by the bioelectrical impedance analysis method. Women had higher leptin and leptin/fat mass values than men in all BMI groups (BMI < 20, 20-23.9, 24-25.9, > or = 26). The leptin concentration correlated significantly with BMI, fat mass, percent fat, waist, hip, waist/hip ratio (W/H), Pmax, Smin and serum Cr in both men and women. The leptin concentration correlated significantly with age in men only and P/S in female only. Leptin/fat mass values significantly correlated with age, fat mass, and percent fat, but not with BMI, waist, hip, W/H, Pmax, Smin and P/S in men. In women, leptin/fat mass values significantly correlated with BMI, fat mass, percent fat, waist, hip, Pmax, Smin and P/S, but not with age or W/H. Multiple regression analysis showed that fat mass and serum creatinine were significant determinants of the leptin and leptin/fat mass values both in men and women, but that age was a significant determinant of these values only in men. These results suggest that the influence of aging on serum leptin concentration exists only in men.

Adipose Tissue↗
PubMed1999

[Multiple primary cancers of oral cavity and pharynx].

Multiple primary cancers were found in 23 of 68 patients (34%) with an index cancer in the oral cavity or pharyngeal area treated in our institute from June 1995 to July 1998. Four cases had triple primary cancers. All 68 cases underwent upper and lower gastrointestinal endoscopy as well as ultrasonography of the liver. Lung CT was performed in cases with abnormal findings on chest roentgenograms. Multiple cancers were found in 5 of 25 oral cavity cases (20%), 6 of 14 mesopharynx cases (43%) and 12 of 29 hypopharynx cases (41%). Nine of 23 cases (39%) were synchronous and 14 (61%) were metachronous. Eighteen of 27 (69%) secondary cancers occurred in the upper aerodigestive tract with an especially high incidence (22%) in the esophagus. Gastroendoscopy also revealed 7 neoplastic lesions, aside from cancers, with the total abnormal rate of 24% (24/68). Thus, gastroendoscopy is useful for the diagnosis of multiple primary cancers. The frequency of multiple primary cancers in males (33%) was not different from that in females (35%). The average age of multiple primary cancer patients (65.1 years) was a little higher than that of single cancer patient (62.7 years). Smoking or drinking was not related to the incidence of multiple cancers. The interval between the first and the second cancer in metachronous cancer cases was 25.5 months on average, and within 4 years in 71% (10/14) of the cases. This result suggests that close follow-up including endoscopy should be required for at least 4 years after treatment of oral or pharyngeal cancer. Radical treatment for each of the multiple cancer lesions was performed in 22 of 23 cases, and the mortality rate of multiple primary cancer cases was not significantly different from that of single cancer cases. Among 7 cases who died of disease, 5 cases died of distant metastasis, suggesting that control of distant metastasis is an important issue in the treatment of multiple primary cancers.

Adult↗
PubMed1999

[Loss of heterozygosity of 3p21 and 9p21 in head and neck squamous cell carcinomas and its prognostic implication].

To examine whether genetic factors influence the prognosis of cancer patients, several microsatellite markers were used to determine the allelic loss of certain areas of the genome. Three microsatellite markers, D3S1067, IFNA and D9S171 were used to study the loss of heterozygosity (LOH) of 3p21 and 9p21 in 93 head and neck squamous cell carcinomas. Of 57 informative cases, LOH was detected in 27 of 57 (47%) DNA samples obtained from cancer specimens when at least one marker was used. The frequency of LOH was not correlated with the clinical factors. However, the frequency of LOH was significantly higher in the recurrent cases than in the non-recurrent cases, and patients with 3p21 and/or 9p21 LOH tended to survive for a shorter period of time. These results suggested that the allelic loss at 3p21 and/or 9p21 could be correlated with the prognosis of the patients, and that it was a novel prognostic factor independent of other clinical factors concerning head and neck cancers. LOH at 3p21 and/or 9p21 may help to identify head and neck cancer patients with a poor prognosis, who need an intensive postoperative follow-up protocol, or who are suitable for novel investigational therapeutic approaches.

Carcinoma, Squamous Cell↗