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Biomedical subjects

K Hosoda

Publications and source records attributed to K Hosoda.

At least 91 records · Page 5Linked to original sources
PubMed1996

Development of radioimmunoassay for human leptin.

Using recombinant human leptin, we have produced an antiserum for human leptin and developed a radioimmunoassay (RIA) specific and sensitive for human leptin. We detected leptin-like immunoreactivity (-LI) in culture media of adipose tissue from subcutaneous abdominal fat in human. The plasma leptin-LI concentration in nonobese subjects (17.6 <body mass index (BMI)<23.0) was 5.6 +/- 1.3 (mean +/-SE) ng/ml, while that in obese subjects (29.0 <BMI) was 43.0 +/- 9.4 (mean +/- SE) ng/ml. In gel permeation chromatographic analyses, leptin-LI in culture media and plasma consisted of single component emerging at the elution position of recombinant human leptin. These findings indicate that leptin is secreted from the adipose tissue into the circulating blood as a large molecular form corresponding to recombinant leptin. The RIA developed in the present study will be a powerful tool to investigate the physiological and pathophysiological significance of leptin in human.

Adipose Tissue↗
PubMed1996

Augmented expression of obese (ob) gene during the process of obesity in genetically obese-hyperglycemic Wistar fatty (fa/fa) rats.

Expression of the obese (ob) gene is up-regulated in the adipose tissue in several obese rodent models. To study the regulation of the ob gene expression during the development of obesity, we examined the ob gene expression in genetically obese-hyperglycemic Wistar fatty (fa/fa) rats at several stages of obesity. The ob mRNA levels in the adipose tissue from Wistar fatty rats was unequivocally augmented and continued to rise in the process of obesity. Furthermore, the ob gene expression in this obese model was much more rapidly enhanced in the mesenteric fat than in the subcutaneous fat. Moreover, the ob gene expression was more greatly augmented in the mesenteric fat than the lipoprotein lipase gene expression. These results suggest the presence of obesity-linked and region-specific regulation of the ob gene expression.

Adipose Tissue↗
PubMed1996

Serum N-terminal osteocalcin is a good indicator for estimating responders to hormone replacement therapy in postmenopausal women.

To estimate the response to hormone replacement therapy (HRT) by bone metabolic markers, 36 patients with postmenopausal osteoporosis or osteopenia were studied to assess the correlation between percent baseline changes in lumbar bone mineral density (BMD) after 12 months and those in various bone metabolic markers after 3, 6, and 12 months of HRT. All the patients were treated with 0.625 mg of conjugated estrogen and 2.5 mg of medroxyprogesterone per day and continued for 12 months. BMD was significantly increased up to 4.19 +/- 0.87% after 6 months and 4.93 +/- 1.27% after 12 months of HRT (p = 0.0001 by analysis of variance). In accordance with this, changes in the levels of osteocalcin (p = 0.041), alkaline phosphatase (p = 0.0001), N-terminal osteocalcin (p = 0.0001), urinary excretion of pyridinoline/Cr (p = 0.0001), and deoxypyridinoline/Cr (p = 0.0001) were significantly decreased, respectively. Among these bone metabolic markers, only the change in the serum N-terminal osteocalcin at 3 months (r = 0.557, p = 0.0022), at 6 months (r = 0.470, p = 0.0184), and at 12 months (r = 0.545, p = 0.0061) significantly correlated with the change in BMD 12 months after HRT. The elution profiles of immunoreactive osteocalcin-related molecules in serum fractionated by reverse-phase high performance liquid chromatography revealed that the N-terminal fragment as well as the intact osteocalcin molecule decreased after 3 months of HRT. These results demonstrate that N-terminal osteocalcin is a suitable predictor for estimating good responders to HRT in postmenopausal women.

Analysis of Variance↗
PubMed1996

Evaluation of the subacute pulmonary and testicular inhalation toxicity of diborane in rats.

This study aimed to clarify the subacute pulmonary and testicular inhalation toxicity of diborane (B2H6, CAS: 19287-45-7) in rats. Male Wistar rats were exposed for 8 weeks to 0.11 or 0.96 ppm of diborane for 6 hr/day, 5 days/week. The control group was exposed to filtered air. Bronchoalveolar lavage fluid (BALF), hematological, biochemical, and histopathological examinations were conducted. Sperm counts and spermatic morphological changes were examined in epididymides, and histopathological examination was carries out in testes. BALF examinations revealed that the percentage of neutrophils increased in a dose-dependent manner and that of macrophages decreased in rats exposed to 0.96 ppm. Quantities of total and individual phospholipids in BALF increased in rats exposed to 0.96 ppm. The proportion of phosphatidylglycerol plus sphingomyelin decreased, and phosphatidylethanolamine and phosphatidylinositol increased in rats exposed to 0.96 ppm. LDH increased in rats exposed to 0.96 ppm, and ALP showed a dose-dependent increase. In serum, alpha 1-antitrypsin and superoxide dismutase activities increased in rats exposed to 0.11 or 0.96 ppm. These changes showed dose-dependent effects on the lung in rats exposed to diborane, possibly indicating that the hyperenergia of type II cells with proliferation and/or hypertrophy without histopathological changes occurred even in rats exposed to 0.11 ppm. Testicular examinations revealed no particular findings. The TLV-TWA of diborane (0.1 ppm) seems to be high and possibly unsafe, considering that the no-observed-effect level over 8 weeks for rat lung was under 0.11 ppm.

Administration, Inhalation↗
PubMed1996

Local bone turnover in the metaphysis of the proximal tibia and the lumbar vertebra during the early periods after ovariectomy in rats.

To clarify the local changes in bone formation and resorption during the early period after ovariectomy (OVX), 200 SD rats, 4 months of age, underwent OVX or sham surgeries and seven to nine rats from each group were terminated at 1, 3, 7, 11, 15, 19, 23, 28, 35, 63, and 91 days postsurgery after tetracycline labeling. Serum intact osteocalcin levels were measured. Undecalcified sections of the 5th lumbar body (L5) and the right proximal tibia were measured for trabecular bone area, the labeled perimeters and the interlabeling distances after Villanueva's staining. On the 4th lumbar body (L4) and the left proximal tibia, undecalcified sections were measured for the trabecular osteoclast by tartrate-resistant acid phosphatase staining. The uterine horns were atrophied on the 3rd postovariectomy day (day 3). Serum osteocalcin levels increased on day 7 and reached the highest value on day 23. In either L5 or the metaphysis of the proximal tibia, trabecular bone volume (BV/TV) significantly decreased on day 15. The trabecular bone loss on day 28 was approximately 50% in the tibia and 15% in the L5. In either the lumbar or the tibia, osteoclast numbers significantly increased at day 3, and peaked between days 15 and 23. In the tibia, however, the bone formation rates (BFR/BS) were significantly reduced on the 3rd and 7th post-surgical days compared with the start value for both the OVX and sham groups. The BFR/BS values in L5 did not decrease during the first 7 days in either group. The BFR/BS values were then increased for both L5 and the tibia after day 7. These data clearly demonstrated that the local bone turnover 7 days post-OVX was identical in the proximal tibia and the lumbar vertebra. In the proximal tibia, however, it may be suggested that the increased bone resorption and reduced formation within 7 days after OVX due to the combined effects of both an estrogen deficiency and the surgical intervention would possibly play a critical role in the greater magnitude of the trabecular bone loss.

Animals↗
PubMed1996

Measurement of intact rat osteocalcin in osteoblast (ROS17/2.8) cells and in ovariectomized rats with a sandwich enzyme immunoassay.

We developed a sandwich enzyme immunoassay system for intact rat osteocalcin to improve the region specificity for the detection of this molecule. We synthesized two peptides of N-terminal 20 residues and C-terminal 10 residues of rat osteocalcin. After conjugating these peptides with carrier protein, we obtained anti-N- and anti-C-terminal rat osteocalcin antibodies in rabbits raised against these two peptides, respectively. By using these antibodies, we measured intact rat osteocalcin levels in a two-site immunoassay manner. These antibodies did not show the cross-reactivity to human osteocalcin. The immunoreactive peak corresponding to the intact molecules was detected by our intact osteocalcin method after high-performance liquid chromatographic fractionation of osteocalcin fragments in plasma from uremic rats. Furthermore, the intact rat osteocalcin was stable over 8 hours at 25 degrees C. Intact rat osteocalcin levels extracellularly secreted from ROS 17/2.8 cells were measured by this method, showing time- and dose-dependent significant increases when administered 1,25(OH)2D3. The inhibition for the secretion of intact osteocalcin by actinomycin D was also detected quantitatively with this method. In ovariectomized rats, intact osteocalcin levels in plasma were acutely elevated after ovariectomy, and its elevation was significantly depressed by 17beta-estradiol administration. These data suggest that this sandwich method is able to measure the intact form of osteocalcin secreted by osteoblasts. As the antibodies identify the specific regions of osteocalcin molecule, this method would be useful for sensitive estimation of bone turnover for various experimental conditions in rats.

Animals↗
PubMed1996

Structure determination of an immunopotentiator peptide, cinnamycin, complexed with lysophosphatidylethanolamine by 1H-NMR1.

The three-dimensional structure of a complex of cinnamycin, a 19-amino acid residue immunopotentiator peptide, and lysophosphatidylethanolamine was determined by 1H-NMR. The complex was cylindrical in shape, 11 A in diameter and 26 A in length, excluding the acyl chain of the phospholipid. The peptide had a hydrophobic pocket surrounded by residues Phe-7 through Ala(S)-14 to bind to the head group of the ligand. Fitting of the head group to the hydrophobic pocket was so good that other than a glycerophosphoethanolamine head group would be unable to fit the pocket. The goodness of the fitting is compatible with the strict specificity of ligand binding of the peptide.

Amino Acid Sequence↗
PubMed1996

Regulation of obese gene expression in KK mice and congenic lethal yellow obese KKAy mice.

To elucidate the regulation of obese (ob) gene expression in obesity and diabetes, we examined ob gene expression in KK mice and congenic lethal yellow obese KKAy mice. Northern blot analysis revealed that the ob mRNA levels are roughly equivalent in each of the epididymal, mesenteric, and subcutaneous white adipose tissue (WAT) from KK and KKAy mice at 4 wk of age, when the obese phenotype of KKAy mice was not apparent. Expression of the ob gene was augmented in the mesenteric and subcutaneous WAT but was unchanged in the epididymal WAT in KKAy mice at 12 wk of age, when KKAy mice developed marked obesity with hyperglycemia, hyperlipidemia, and hyperinsulinemia. The ob gene expression was also examined during fasting in 12-wk-old KK and KKAy mice. After 24 or 72 h of fasting in both mouse strains, ob gene expression was downregulated in the epididymal and mesenteric WAT but was unchanged in the subcutaneous WAT. The present study demonstrates that adipose tissue expression of the ob gene is regulated depending on the nutritional status in KK and KKAy mice.

Animals↗
PubMed1996

Endothelin-1 and its receptor in hypertrophic cardiomyopathy.

Endothelin-1, a potent vasoconstrictor produced by vascular endothelial cells, activates the hypertrophic program in cultured heart muscle cells. However, the role of endothelin-1 in cardiac hypertrophy in humans is unknown. Therefore, we studied hypertrophic cardiomyopathy patients with normal pulmonary arterial pressure, in whom cardiac hypertrophy is a specific feature of the disease. Radioimmunoassay with a monoclonal antibody to human endothelin-1 showed that the plasma level of immunoreactive endothelin was more than twofold higher in hypertrophic cardiomyopathy patients than in control subjects (P < .005). In situ hybridization analysis of endomyocardial biopsy specimens showed positive signals of endothelin-1 type A receptor mRNA in ventricular myocytes of all specimens. The receptor expression in ventricular myocytes was similar between hypertrophic cardiomyopathy patients and control subjects. We propose that endothelin-1 might represent an important factor involved in hypertrophic cardiomyopathy. Whether endothelin-1 plays a causal role in cardiac hypertrophy or is a marker of its occurrence needs to be clarified.

Analysis of Variance↗
PubMed1996

Multiple burr-hole operation for adult moyamoya disease.

Excellent results from multiple burr-hole operations for adult moyamoya disease are reported in this study. Ten patients had between one and four burr holes (mean 2.1) drilled in each hemisphere. In four patients new burr holes were added on the opposite side after depression of cerebral blood flow (CBF) was detected by follow-up single-photon emission computerized tomography imaging of the brain with N-isopropyl-p-[123I]iodoamphetamine. The postoperative follow-up period ranged from 6 to 62 months (mean 34.7 months). Beginning at 6 months postsurgery, angiograms disclosed rich neovascularization at 41 of 43 burr holes, first from the middle meningeal artery, then from the superficial temporal artery. Neovascularization did not occur at two burr holes at which there was subdural effusion and local cerebral atrophy, respectively. Progression of stenosis of the major vessels was seen in six patients. Moyamoya vessels were decreased at six sites in four patients. The CBF study revealed that the reactivity to acetazolamide improved in all six patients tested. Transient ischemic attacks disappeared in all six patients presenting with this symptom, and preoperative symptoms improved in both of the patients who presented with cerebral infarction and in both patients with intraventricular hemorrhage. There was no mortality or morbidity, and no new neurological deficits or rebleeding developed during the follow-up period. The authors strongly recommend the multiple burr- hole operation as the surgical treatment of choice for adult moyamoya disease because of its safety and effectiveness.

Adult↗
PubMed1995

Augmented expression of the obese gene in the adipose tissue from rats fed high-fat diet.

Expression of the obese (ob) gene is augmented in the adipose tissue in several rodent models of genetic obesity. In the present study, we examined the ob gene expression in a rodent model of acquired obesity obtained by pure overfeeding of normal rats. Male Sprague-Dawley rats at 8 weeks of age were fed standard diet or high-fat diet. Rats fed high-fat diet developed moderate degree of obesity, hyperglycemia, and hyperlipidemia as compared with rats fed standard diet. Northern blot analysis revealed that the ob gene is expressed abundantly in the adipose tissue obtained from the epididymal, mesenteric, subcutaneous, retroperitoneal, and interscapular fat pads in rats fed standard diet. Expression of the ob gene was augmented in all the adipose tissue examined in rats fed high-fat diet. The present study demonstrates that the ob gene expression is augmented in the adipose tissue in diet-induced obesity, thereby suggesting the pathophysiologic roles of the ob gene in acquired obesity.

Adipose Tissue↗
PubMed1995

Sandwich immunoassay specific for the N-terminal sequence of osteocalcin.

A monoclonal antibody (10B) against the N-terminal sequence of human osteocalcin was selected to characterize its epitope and species specificity. The cross-reactivity of 10B with human and rat osteocalcin demonstrated that the reactivities of 10B with both human and rat osteocalcins were very similar. The pin technology method was used to determine the epitope and clearly demonstrated that the epitope recognized by 10B was localized to residues 12-16, the sequence of which is identical in rat and human osteocalcin molecules. This monoclonal antibody was found to be useful for designing region-specific sandwich immunoassay systems for human and rat N-terminal osteocalcin (N-OC) molecules using rabbit anti-hN20 and anti-rN20 polyclonal antibodies, respectively. The osteocalcin levels in serum determined by this N-OC method were stable during prolonged storage at 25 degrees C and the method could be usefully applied in the development of immunoassay systems for many osteocalcin molecules from many other species.

Amino Acid Sequence↗
PubMed1995

Tau in cerebrospinal fluids: establishment of the sandwich ELISA with antibody specific to the repeat sequence in tau.

Clinical diagnosis for Alzheimer's disease (AD) is provided by the criteria of DSMIV and clinical progress in addition to imaging analysis with MRI after negative screening. The final exclusive diagnosis is confirmed by the neuropathological findings of neurofibrillary tangles and senile plaques in autopsy brains. We developed a new ELISA system to measure the amount of tau in cerebrospinal fluids (CSF) using phosphorylation-independent and sequence-specific antibodies. The present ELISA was sensitive enough to detect tau in CSF of normal subjects. The amount of tau was significantly elevated in CSF of AD subjects compared with those of normal subjects and subjects with dementia of cerebrovascular disease, suggesting that tau in CSF reflects the massive and continuous neuronal cell death in the AD brain. In conclusion, we established an ELISA system which enabled us to detect tau in CSF and demonstrated that tau was significantly and specifically elevated in CSF of AD subjects. This assay system can provide us with a potent diagnostic tool for clinical AD.

Alzheimer Disease↗
PubMed1995

Efficacy of longterm interferon treatment in chronic liver disease evaluated by sensitive polymerase chain reaction assay for hepatitis C virus RNA.

Effects of interferon treatment on hepatitis C virus were examined by investigating the presence of hepatitis C virus ribonucleic acid and anti-hepatitis C virus antibody in 70 patients with non-A, non-B chronic liver diseases. Twenty one patients were treated with three million units of interferon alfa 2a three times a week for 52 weeks, 24 patients were treated similarly for eight weeks, and 25 patients were given a placebo for eight weeks and served as control. Sixty six of 70 patients (94%) were positive for both hepatitis C virus RNA and second generation anti-hepatitis C virus antibody. Fourteen of 21 (67%) receiving the longterm treatment had a normalised alanine aminotransferase (ALT) activity, and in 12 of these hepatitis C virus ribonucleic acid became undetectable by the end of treatment and remained so during the three year follow up after the treatment. Anti-hepatitis C virus antibody determined by first generation assay became negative in one case at the end of the 52 week treatment, and in four cases at the end of the one year follow up. In contrast, only one of 24 (4%) who received the eight week treatment and only one of 25 (4%) who received the placebo had normalised ALT activities. Hepatitis C virus ribonucleic acid became negative in two patients undergoing short-term treatment and in none receiving the placebo. Thus, longterm interferon treatment seems effective in clearing hepatitis C virus from serum of patients with chronic liver disease.

Adult↗
PubMed1995

Aberrant appearance of lung surfactant protein A in sera of patients with idiopathic pulmonary fibrosis and its clinical significance.

Pulmonary surfactant protein A (SP-A) is known to be a major phospholipid-associated glycoprotein in pulmonary surfactant, which is specific to the lung. In this study, the SP-A concentrations in sera of patients with various lung diseases were determined using an enzyme-linked immunosorbent assay. Patients with idiopathic pulmonary fibrosis (IPF) and pulmonary alveolar proteinosis (PAP) exhibited prominently high concentrations of serum SP-A compared to those of other lung diseases and healthy volunteers, although there were significant increases in serum SP-A concentrations in patients with pulmonary tuberculosis, chronic pulmonary emphysema, diffuse panbronchiolitis and bacterial pneumonia compared to those of healthy volunteers. Successive measurement in 2 patients with IPF showed that serum SP-A levels reflect the disease activity of IPF. In patients with IPF, serum SP-A concentrations were significantly correlated with those of serum lactate dehydrogenase, whereas there were no significant correlations of serum SP-A concentrations with erythrocyte sedimentation rate, arterial oxygen saturation, vital capacity and carbon monoxide diffusing capacity. Determination of serum SP-A will contribute to diagnosing IPF and PAP, and may reflect the disease activity of IPF.

Biomarkers↗
PubMed1995

A morphologic study of lung secretory leukoprotease inhibitor in pneumonia.

The present study was undertaken to determine the localization of cells laden with secretory leukoprotease inhibitor (SLPI) in bronchial/bronchiolar epithelium (B/Br-E) by histochemical techniques to see whether SLPI production occurs in conjunction with pathologic bronchopneumonia. Ten lung were obtained at autopsy from patients between 63 and 100 yr of age, including six with pathologic pneumonia and four without pneumonia. SLPI-laden cells in the B/Br-E corresponded mostly to goblet cells with apparent hyperplasia. A morphometric study performed on the B/Br-E indicated that the percentage of SLPI-laden cells was significantly correlated with the percentage of mucus-containing cells (r = 0.72, p < 0.001). This trend was similar in the bronchi (r = 0.60, p < 0.05) and in the bronchioles (r = 0.90, p < 0.01). The increased percentage of mucus and SLPI-laden cells in the B/Br-E was closely correlated with acute inflammatory changes in the adjacent alveoli, particularly in bronchi rather than in bronchioles. From these observations we conclude that the number of SLPI-laden cells in the airways increases in correlation with goblet cell hyperplasia. In addition, these morphologic changes are associated with the existence of acute inflammatory cell infiltration in the alveolar area.

Aged↗
PubMed1995

Molecular cloning of rat obese cDNA and augmented gene expression in genetically obese Zucker fatty (fa/fa) rats.

The obese (ob) gene has recently been isolated through a positional cloning approach, the mutation of which causes a marked hereditary obesity and diabetes mellitus in mice. In the present study, we isolated rat ob cDNA and examined the tissue distribution of the ob gene expression in rats. We also studied the gene expression in genetically obese Zucker fatty (fa/fa) rats. The rat ob gene product, a 167 amino acid protein with a putative signal sequence, was 96 and 83% homologous to the mouse and human ob proteins, respectively. Northern blot analysis using the rat ob cDNA probe identified a single mRNA species of 4.5 kb in size in the adipose tissue, while no significant amount of ob mRNA was present in other tissues in rats. The ob gene was expressed in the adipose tissue with region specificities. The rank order of the ob mRNA level in the adipose tissue was epididymal, retroperitoneal, and pericardial white adipose tissue > mesenteric and subcutaneous white adipose tissue > or = interscapular brown adipose tissue. The ob gene expression occurred in mature adipocytes rather than in stromalvascular cells isolated from the rat adipose tissue. Expression of the ob gene was markedly augmented in all the adipose tissue examined in Zucker fatty (fa/fa) rats at the stage of established obesity. The present study leads to the better understanding of the physiologic and pathophysiologic roles of the ob gene.

Adipose Tissue↗