Biomedical subjects

H Koyama

Publications and source records attributed to H Koyama.

At least 127 records · Page 7Linked to original sources

PubMed1999

Cloning of translocation breakpoints associated with Shwachman syndrome and identification of a candidate gene.

Shwachman syndrome is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency, bone-marrow dysfunction, and metaphyseal chondrodysplasia. A de novo balanced translocation was recently documented in a patient with this disease. Toward isolating the gene(s) responsible for Shwachman syndrome, we cloned and sequenced the translocation breakpoints in the DNA of this patient. The nucleotide sequences around the breakpoints contained neither repetitive elements nor motifs reported to be implicated in recombination events, although we did detect gains or losses of oligonucleotides at the translocation junctions. By large-scale genomic sequencing and in silico gene trapping, we identified two novel transcripts in the vicinity of the breakpoints that might represent candidate genes for Shwachman syndrome, one on chromosome 6 and the other on chromosome 12. The gene on chromosome 12 was actually disrupted by the translocation.

Amino Acid Sequence↗

PubMed1999

Sentinel node biopsy guided by indocyanine green dye in breast cancer patients.

BACKGROUND: We aimed to evaluate whether dye-guided sentinel node biopsy is a useful indicator of axillary node involvement in breast cancer patients and whether clinicopathological features affect its success in identifying sentinel nodes. METHODS: Sentinel node biopsy was performed in patients with stage I or II breast cancer using an indocyanin green dye-guided method. RESULTS: We could identify sentinel nodes in 127 (73.8%) of 172 patients. The mean number of sentinel nodes per patient was 1.7 (range, 1-8) and the mean node size was 9.3 mm (range, 3.0-28.0 mm). Of the 127 patients, 40 (31.5%) also had axillary node involvement. In 16 (40.0%) of these, the sentinel node was the only node involved. There was concordance between sentinel node and axillary node status in 122 (96.1%) of the 127 patients. Success in identifying sentinel nodes was not affected by tumor size, operative procedure, histological type of tumor or tumor location; however, the success rate was significantly lower in patients with axillary node involvement (65.7 vs 79.0% in axillary node-negative patients, p = 0.039) and the presence or absence of lymphatic or vascular invasion in the tumor (63.8 vs 78.9% in patients without lymphatic or vascular invasion, p = 0.043). Sentinel nodes could also be identified significantly more frequently in patients under 50 years old (83.3%) than in those over 50 years old (64.8%, p = 0.009). CONCLUSIONS: Sentinel node biopsy guided by indocyanin green dye is an easy technique with an acceptable success rate in detecting sentinel nodes and predicting axillary nodal status. Axillary node status, the presence or absence of lymphatic or vascular invasion in the tumor and patient age affect its success in identifying sentinel nodes.

Adult↗

PubMed1999

Risk factors for breast cancer in Japan, with special attention to anthropometric measurements and reproductive history.

BACKGROUND: Breast cancer incidence has increased rapidly in Japan recently, but there have been only a few studies on the risk factors for breast cancer in Japan. A case-control study was conducted to evaluate the roles of anthropometric and reproductive factors in the etiology of breast cancer in Osaka. METHODS: Based on information from a self-administered questionnaire at Osaka Medical Center for Cancer and Cardiovascular Diseases, body mass index, body weight and height were compared between 376 cases and 430 controls, together with other factors such as age at menarche, age at first delivery and family history of breast cancer by menopausal status. Logistic regression analysis was employed for adjusting confounding factors and estimating odds ratios with their 95% confidence interval for breast cancer. RESULTS: A body mass index of >25 was significantly associated with the risk among post-menopausal women (age-adjusted odds ratio: 1.90, 95% confidence interval: 1.10-3.24) as compared with the risk for a body mass index of < or = 20. A weight of > or =58 kg showed significantly increased risk compared with a weight of < or = 47 kg among post-menopausal women (1.83, 1.10-3.01), while height of > or = 159 cm showed a significantly elevated risk than height of < or = 149 cm among pre-menopausal women (2.51, 1.17-5.39). Age at menarche of < or = 13 years resulted in a higher risk of breast cancer among post-menopausal women, while age at first delivery of > or = 28 years was associated with the risk among pre-menopausal women. Family history of breast cancer was associated with the risk for breast cancer. CONCLUSIONS: These results were all very consistent with findings observed in western countries.

Adult↗

PubMed1999

Alphav integrin regulates TNF-alpha-induced nitric oxide synthesis in rat mesangial cells--possible role of osteopontin.

BACKGROUND: Tumour necrosis factor-alpha (TNF-alpha) induces nitric oxide (NO) synthesis in rat mesangial cells (MCs). We previously demonstrated that osteopontin (OP), a matrix protein that mainly interacts with the alphav integrin family, increased time-dependently by TNF-alpha stimulation at gene and protein levels. The regulation of NO synthesis by integrins or matrix proteins is unclear. METHODS: We examined whether integrin, especially alphav integrin, regulates NO synthesis in rat MCs and whether OP, an alphav integrin ligand, has an effect on TNF-alpha-induced NO synthesis. Furthermore, OP and inducible NO synthase (iNOS) gene expression was examined by Northern blotting. RESULTS: TNF-alpha increased NO synthesis in MCs in a time-dependent manner. Synthetic GRGDSP peptide, which is known to inhibit various integrins that interact with RGD-containing extracellular matrices, increased TNF-alpha-induced NO levels in a dose-dependent manner. Cyclical RGD peptide, the specific inhibitor of alphav integrin, also exhibited a dose-dependent effect of increasing NO levels, while GRGESP peptide, which has very low affinity to integrins, had no effect. In addition, NO synthesis was found to be significantly reduced when MCs were plated on OP-coated dishes compared to type I or IV collagen-coated dishes. Furthermore, anti-OP antibody increased NO synthesis in MCs. iNOS mRNA levels were increased by TNF-alpha, and were abruptly diminished after OP mRNA was significantly induced. CONCLUSIONS: The present study demonstrated the involvement of alphav integrin in TNF-alpha-induced NO synthesis in rat MCs, and the possible role of OP was suggested in the mechanism. TNF-alpha and extracellular matrices can co-operate to regulate the behaviour of MCs at least partly through NO synthesis, which may participate in the course of glomerular diseases.

Animals↗

PubMed1999

Over expression of mitochondrial citrate synthase gene improves the growth of carrot cells in Al-phosphate medium.

A mitochondrial citrate synthase (CS) of Arabidopsis thaliana was introduced into carrot (Daucus carota L. cv. MS Yonsun) cells by Agrobacterium tumefaciens-mediated transformation. Transgenic cell lines had high CS activity, the highest value observed was 0.24 mumol (mg protein)-1 min-1 which was 1.9-fold of that in wild-type cells. Transcript levels of DcCS were similar between transgenic lines, but those of AtCS were increased as the CS activity of cells was increased. Isoelectric focussing revealed that the CS polypeptide of the transgenic lines had a pI value different from that of the wild-type cells, although the molecular mass was the same. These results indicate that the CS polypeptides of A. thaliana were expressed and processed to the mature form in carrot cells. The growth rate and excretion was 2.2-2.8 and 2.8-4.0 fold greater in the transgenic cells than in the wild type cells, respectively. Phosphate uptake from Al-phosphate also increased in transgenic cells. It appears, the overexpression of mitochondrial citrate synthase in carrot cells improves the growth rate in Al-phosphate medium possibly as a result of increased citrate excretion.

Agrobacterium tumefaciens↗

PubMed1999

Development of cellular polarity of hamster embryos during compaction.

Development of cellular polarity is an important event during early mammalian embryo development and differentiation. Blastomeres of hamster embryos at various stages were examined by scanning electron microscopy (SEM) and immunocytochemical staining. SEM observations revealed that 1- to 7-cell-stage embryos showed a uniform distribution of microvilli throughout the cell surface. Microvillous polarization was initially noted in the blastomeres (10-35%) of 8-cell-stage embryos. The polarized microvilli were observed mostly in the basal region of cell-cell contact and occasionally at the apical, outward-facing surface of the blastomere. Fluorescein-isothiocyanate-conjugated concanavalin A failed to reveal any polarity in the blastomeres regardless of the stages of the embryos. Actin staining showed that microfilaments were present beneath the cell surface, and in addition, areas of cell contact were more heavily stained, indicating a thick microfilament domain. Microtubules were located throughout the cytoplasm and were heavily concentrated near the nucleus during interphase, although they became redistributed in the region of the mitotic spindle during karyokinesis. The position of nucleus changed from the cell center to the apical, outward-facing surface of the cell, and it distanced itself from the basal microvillous pole. It is suggested that the changes in the cell surface and nuclear position are the first manifestations of cell polarity in peri-compacted hamster embryos, which appear as early as the 8-cell stage; furthermore, the outward migration of the nuclei may parallel the redistribution of microtubules in the cytoplasm.

Animals↗

PubMed1999

Comparison of the hemodynamic effects of amrinone in patients who required low-to-moderate-dose and high-dose catecholamines after cardiac valve replacement.

OBJECTIVES: To determine hemodynamic response to amrinone in patients after cardiac surgery, in relation to the postoperative cardiac function, which was indicated by the required doses of catecholamines. DESIGN: Prospective clinical study. SETTING: Surgical intensive care unit in a university hospital. PATIENTS: Fourteen patients who required a low-to-moderate dose of dopamine and dobutamine (group L) and 14 patients who required a high dose of dopamine and dobutamine (group H) after cardiac valve replacement. INTERVENTIONS: A loading dose of amrinone (0.75 mg/kg) was administered during a 15-min period and the continuous infusion was followed incrementally by doses of 5, 10, and 20 microg/kg/min every 60 mins on the first postoperative day. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables were determined by the radial and pulmonary artery catheters at a dose of 0, 5, 10, and 20 microg/kg/min. Two-way repeated-measures analysis of variance showed significant interaction in the two groups in cardiac index and mean systemic arterial pressure. Cardiac index increased in a dose-dependent manner in group L but was unchanged in group H. Systemic vascular resistance index decreased in a dose-dependent manner in both groups. The mean systemic arterial pressure decreased in group L at a dose of 5 microg/kg/min and returned to the baseline level at doses of 10 and 20 microg/kg/min. On the other hand, the mean systemic arterial pressure significantly decreased in group H at a dose of 20 microg/kg/min. CONCLUSIONS: The inotropic effects of amrinone after cardiac valve replacement may be associated with the postoperative myocardial reserve, which was indicated by the required doses of catecholamines, although a similar vasodilative effect was observed in both groups.

Adult↗

PubMed1999

Errors in the spleen-blood partition coefficient for water in C15O2 steady-state PET.

The aim of this study was to clarify if the value of 0.93, determined for patients with normal livers, is useful as a pathological spleen-blood partition coefficient for water when the splenic blood flow is quantified by the C15O2 steady-state method. A steady-state PET scan with continuous inhalation of C15O2 and a dynamic PET scan with a H(2)15O bolus injection were performed. From 157 patients, 392 slices were chosen as having planes that encompassed the spleen and provided regions of interest with full signal imaging. A comparison of the results of the steady-state and dynamic methods was performed. When 0.93 was adopted as the spleen-blood partition coefficient for water, an error of about 25% was seen in the splenic blood flow of patients with cirrhosis. When measuring splenic blood flow, the H(2)15O dynamic method is necessary. However, a rough estimate of splenic blood flow is possible by the C15O2 PET steady-state method, if this error is known.

Adult↗

PubMed1999

Temporal and spatial patterns of accumulation of the transcript of Myo-inositol-1-phosphate synthase and phytin-containing particles during seed development in rice.

Myo-inositol-1-phosphate (I[1]P) synthase (EC 5.5.1.4) catalyzes the reaction from glucose 6-phosphate to I(1)P, the first step of myo-inositol biosynthesis. Among the metabolites of I(1)P is inositol hexakisphosphate, which forms a mixed salt called phytin or phytate, a storage form of phosphate and cations in seeds. We have isolated a rice (Oryza sativa L.) cDNA clone, pRINO1, that is highly homologous to the I(1)P synthase from yeast and plants. Northern analysis of total RNA showed that the transcript accumulated to high levels in embryos but was undetectable in shoots, roots, and flowers. In situ hybridization of developing seeds showed that the transcript first appeared in the apical region of globular-stage embryos 2 d after anthesis (DAA). Strong signals were detected in the scutellum and aleurone layer after 4 DAA. The level of the transcript in these cells increased until 7 DAA, after which time it gradually decreased. Phytin-containing particles called globoids appeared 4 DAA in the scutellum and aleurone layer, coinciding with the localization of the RINO1 transcript. The temporal and spatial patterns of accumulation of the RINO1 transcript and globoids suggest that I(1)P synthase directs phytin biosynthesis in rice seeds.

Amino Acid Sequence↗

PubMed1999

Melatonin stimulates proliferation and type I collagen synthesis in human bone cells in vitro.

The pineal secretory product melatonin reportedly regulates release of growth hormone in humans and prevents phototherapy-induced hypocalcemia in newborn rats, suggesting that melatonin affects bone metabolism. Little is known about the effects of melatonin on bone in vitro or in vivo. The present study was undertaken to examine whether melatonin acts directly on normal human bone cells (HOB-M cells) and human osteoblastic cell line (SV-HFO cells) to affect osteogenic action in vitro. The effect of melatonin on bone cell proliferation was determined using the 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carbo xanilide (XTT) assay after a 24 hr incubation with melatonin. Melatonin significantly and dose-dependently increased the proliferation in HOB-M cells and SV-HFO cells by 215 +/- 22.1%, and 193 +/- 6.4%), respectively, with a maximal effect at a concentration of 50 microM. To evaluate the effect of melatonin on bone cell differentiation, alkaline phosphatase (ALP) activity, osteocalcin secretion and procollagen type I c-peptide (PICP) production (a measure of type I collagen synthesis) were measured after a 48 hr treatment. While melatonin at micromolar concentrations did not significantly affect either the ALP activity or the osteocalcin secretion, it significantly and dose-dependently increased the PICP production in HOB-M cells and SV-HFO cells by 983 +/- 42.2%, and 139 +/- 4.2%, respectively, with the maximal stimulatory doses between 50 and 100 microM. These results provide new evidence that melatonin stimulates the proliferation and type I collagen synthesis in human bone cells in vitro, suggesting that melatonin may act to stimulate bone formation.

Alkaline Phosphatase↗

PubMed1999

Severe impairment in early host defense against Candida albicans in mice deficient in myeloperoxidase.

Myeloperoxidase (MPO) catalyzes the reaction of hydrogen peroxide with chloride ion to produce hypochlorous acid (HOCl), which is used for microbial killing by phagocytic cells. Despite the important role of MPO in host defense, however, MPO deficiency is relatively common in humans, and most of these individuals are in good health. To define the in vivo role of MPO, we have generated by gene targeting mice having no MPO activity in their neutrophils and monocytes. The mice without MPO developed normally, were fertile, and showed normal clearance of intraperitoneal Staphylococcus aureus. However, they showed increased susceptibility to pneumonia and death following intratracheal infection with Candida albicans. Furthermore, the lack of MPO significantly enhanced the dissemination of intraperitoneally injected C. albicans into various organs during the first 7 days. Thus, MPO is important for early host defense against fungal infection, and the inability to generate HOCl cannot be compensated for by other oxygen-dependent systems in vivo in mice. The mutant mice serve as a model for studying pulmonary and systemic candidiasis.

Animals↗

PubMed1999

A randomized controlled comparative study of oral medroxyprogesterone acetate 1,200 and 600 mg in patients with advanced or recurrent breast cancer.

A randomized controlled comparative study of oral medroxyprogesterone acetate (MPA) 1,200 mg (arm I) and 600 mg (arm II) was conducted in 80 patients with advanced or recurrent breast cancer. There were no significant differences between arm I and arm II in terms of response rate, duration of response and survival, or in terms of incidence and severity of adverse reactions. The lowest serum MPA concentration in responders tended to be higher than that in nonresponders. In the cohort of this study, the lowest concentration in partial response was 17.4 ng/ml, suggesting that this level may be the required minimum serum concentration.

Antineoplastic Agents, Hormonal↗

PubMed1999

Malignant seeding of the lumpectomy cavity upon breast-conserving surgery.

One of the etiologic factors involved in local recurrence after breast-conserving surgery may be malignant seeding of the wound during the lumpectomy procedure. A total of 340 patients with stage I and II breast cancer were entered into the study. Of these, 270 patients received breast-conserving surgery (BCS group), and the other 70 patients underwent mastectomy (control group). After resection, lavage cytology was performed at the surgical wound. There were 55 patients (20.4%) who showed positive lavage cytology in the BCS group. In the control group, there were only 3 patients (4.3%) with positive cytology. Positivity was significantly higher in the former group (p = 0.00064). Patients with evidence of cutting across cancer lesions showed significantly higher positive rates in lavage cytology (p < 0.00001). Positivity in lavage cytology was significantly higher in patients with positive surgical margins evaluated by frozen sections (p = 0.0017), touch cytology (p < 0.0001) and formalin-fixed, paraffin-embedded sections (lateral or medial margin; p = 0.0036, anterior and posterior margin: p = 0.0210). The positivity was also significantly higher in patients with an extensive intraductal component (p < 0.0001), and less than or equal to 50 (p = 0.0061) years of age. Multivariate analysis revealed that the highest relative risk factor for positive cytology was evidence of cutting across cancer lesions (relative risk = 8. 166; p < 0.00001).

Adult↗

PubMed1999

Comparison of the bronchodilator effects of salbutamol delivered via a metered-dose inhaler with spacer, a dry-powder inhaler, and a jet nebulizer in patients with chronic obstructive pulmonary disease.

The aim of this study was to compare the bronchodilator effects of salbutamol delivered via three different devices: a dry-powder inhaler (DPI), a metered-dose inhaler (MDI) with a large-volume spacer and a jet nebulizer (NEB) in patients with stable chronic obstructive pulmonary disease (COPD). Ten male patients with stable COPD [age: 67.2 +/- 3.8 years, forced expiratory volume in 1 s (FEV1): 1.56 +/- 0.32 liters] were studied in a randomized, double-blind and crossover manner. Each patient received 200 or 1, 000 microg salbutamol via an MDI with an InspirEaseTM spacer, a RotahalerTM, or a DeVilbiss 646(TM) nebulizer (NEB), or matching placebo on 7 separate days. Spirometry was performed before and 15, 30, 60, 90, 120, and 240 min after inhalation. With the 200- microg dose, only DPI produced a small but greater response in maximum FEV1 and in area under the time-response curve (AUC-FEV1) compared with placebo. With the 1,000- microg dose, DPI and MDI produced equally greater improvements in both maximum FEV1 and AUC-FEV1 than NEB. An equal bronchodilating effect can be obtained using either DPI or MDI with a spacer device, whereas the NEB was less effective when the same dose was administered.

Administration, Inhalation↗

PubMed1999

A novel, short, and simple questionnaire to measure health-related quality of life in patients with chronic obstructive pulmonary disease.

A novel, short, and simple questionnaire, the Airways Questionnaire 20 (AQ20), has been developed to measure and quantify disturbances in the health-related quality of life (HRQoL) of patients with asthma or chronic obstructive pulmonary disease (COPD). The AQ20 has 20 items with yes/no responses, and should take 2 min to complete and score. The purpose of this study was to assess the discriminative properties and responsiveness of the AQ20 in patients with COPD. First, in a cross- sectional study, 165 patients with mild-to-severe COPD (mean age, 69 +/- 7 yr; FEV1, 40 +/- 16% of predicted) completed the AQ20, the St. George's Respiratory Questionnaire (SGRQ), the Chronic Respiratory Disease Questionnaire (CRQ), pulmonary function tests, a progressive cycle ergometer exercise test, and an assessment of their dyspnea and anxiety. The score distribution of the AQ20 was skewed toward the mild end of the scale, whereas the SGRQ and CRQ showed a normal distribution. The AQ20 showed a moderately strong correlation with the maximal oxygen uptake and the assessment of dyspnea (Spearman's correlation coefficients [rs] = -0.49, -0.60, respectively), but a weak correlation with the FEV1 (rs = -0.18). Moderate to strong correlations were also recognized between the AQ20 and SGRQ and CRQ (rs = -0.80, -0.72, respectively). Multiple regression analysis revealed that dyspnea and anxiety accounted for 43% of the variance in the AQ20, almost the same as in the SGRQ and CRQ. Second, longitudinal changes over time in the FEV1, AQ20, SGRQ, and CRQ were examined in 86 patients with newly detected COPD (mean age, 69 +/- 8 yr; FEV1, 45 +/- 19% of predicted). All three measures showed significant improvements in their scores over a 3-mo period after initiating medical intervention. The change in the AQ20 showed a moderate to strong correlation with each dimension of the SGRQ and CRQ (rs = 0.56, -0.52, respectively), but no significant correlation was noted with the FEV1. In conclusion, the AQ20 may have discriminative properties and responsiveness that are similar to more complex questionnaires such as the SGRQ and CRQ. Because it is short and can be quickly answered and scored, the AQ20 may be useful in studies with limited time for HRQoL assessments.

Aged↗

PubMed1999

Water channel protein AQP3 is present in epithelia exposed to the environment of possible water loss.

Aquaporins (AQPs) are membrane water channel proteins expressed in various tissues in the body. We surveyed the immunolocalization of AQP3, an isoform of the AQP family, in rat epithelial tissues. AQP3 was localized to many epithelial cells in the urinary, digestive, and respiratory tracts and in the skin. In the urinary tract, AQP3 was present at transitional epithelia. In the digestive tract, abundant AQP3 was found in the stratified epithelia in the upper part, from the oral cavity to the forestomach, and in the simple and stratified epithelia in the lower part, from the distal colon to the anal canal. In the respiratory tract, AQP3 was present in the pseudostratified ciliated epithelia from the nasal cavity to the intrapulmonary bronchi. In the skin, AQP3 was present in the epidermis. Interestingly, AQP3 was present at the basal aspects of the epithelia: in the basolateral membranes in the simple epithelia and in the multilayered epithelia at plasma membranes of the basal to intermediate cells. During development of the skin, AQP3 expression commenced late in fetal life. Because these AQP3-positive epithelia have a common feature, i.e., they are exposed to an environment of possible water loss, we propose that AQP3 could serve as a water channel to provide these epithelial cells with water from the subepithelial side to protect them against dehydration. (J Histochem Cytochem 47:1275-1286, 1999)

Aging↗

PubMed1999

Age-related alteration of carbamazepine-serum protein binding in man.

To determine whether biological maturation influences the kinetics of carbamazepine-serum protein binding, the carbamazepine free fraction (%) was investigated in the serum of 66 patients, ranging from 4 to 83 years, with epilepsy or trigeminal neuralgia, treated with carbamazepine alone or carbamazepine in combination with phenytoin, phenobarbital, and/or valproic acid, over a relatively long period. Biochemical parameters such as levels of albumin and non-glycated albumin showed a significant relationship with carbamazepine free fraction (r = -0.521, P < 0.001 for albumin; r = -0.700, P < 0.001 for non-glycated albumin). Non-glycated albumin was more strongly correlated with carbamazepine free fraction. The biochemical parameters showed a significant relationship with age (r =-0.243, P < 0.1 for albumin; r =0.666, P < 0.001 for glycated albumin; r = -0.459, P < 0.001 for non-glycated albumin; r = 0.640, P < 0.001 for carbamazepine free fraction). Glycated albumin (%), non-glycated albumin and carbamazepine free fraction (%) were strongly correlated with age, whereas albumin showed only a weak correlation with age. To evaluate the effects of ageing on carbamazepine-serum protein binding, the patients were divided into three groups according to age: children, 4-15 years; adults, 16-64 years; elderly, 65-83 years. Albumin and non-glycated albumin were much lower, and glycated albumin (%) and carbamazepine free fraction (%) much higher in the elderly group than in the other two groups. The results of this study showed that the major ligand of carbamazepine in the serum was non-glycated albumin, which decreased with age. These observations suggested that in elderly patients, the elevation of free carbamazepine concentrations in the serum caused by reduced non-glycated albumin levels, induces increases in the sensitivity of the pharmacological effects of carbamazepine and the risk of drug interactions.

Adolescent↗

PubMed1999

A simple hydroponic culture method for the development of a highly viable root system in Arabidopsis thaliana.

In the studies of nutritional absorption and metal toxicity in the root, it is important to grow plants without technical damage. We established a simple hydroponic culture system for Arabidopsis thaliana to obtain a healthy plant having a well-developed root system with many lateral roots. The phytotoxic effects of Cr, Cu, and Al ions were examined by FDA-PI staining using this culture system. The pattern of root inhibition varied with the ion, suggesting the usefulness of this culture system.

Aluminum↗