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Biomedical subjects

K Fujiwara

Publications and source records attributed to K Fujiwara.

At least 55 records · Page 3Linked to original sources
PubMed2002

Relation between colour vision loss and occupational styrene exposure level.

AIMS: To investigate the relation between colour vision loss and the exposure level of styrene. Exposure level included the current exposure concentration, past cumulative exposure, and the maximum exposure level in the past. METHODS: Colour vision was examined by the Lanthony desaturated panel D-15 test for 76 subjects exposed to styrene in a fibreglass reinforced plastics boat plant (as an exposed group) and 102 non-exposed subjects (as a control group). The current exposure level was expressed by the concentration of atmospheric styrene and end shift urinary mandelic acid (MA) and phenylglyoxylic acid (PGA) levels. The individual cumulative exposure index (CEI) was calculated, based on the exposure frequency and urinary MA concentrations measured for the past eight years. RESULTS: The Colour Confusion Index (CCI) of the exposed group showed a significant difference from the age matched controls. However, only a slight significant relation was found between CCI and the concentration of urinary MA plus PGA. In this study, the exposed group was further divided into two subgroups (as sub-MA+PGA groups) by the median of urinary MA plus PGA of each subject. The dividing line between the subgroups was 0.24 g/g creatinine, which was equivalent to an atmospheric concentration of styrene of about 10 ppm. The CCI values of both the sub-MA+PGA groups were significantly higher than that of the control group. The relation between CCI value and the maximum exposure concentration in the past eight years was examined. It was found that the CCI values of the group with the maximum exposure concentration of styrene over 50 ppm were significantly higher than that of the other groups. CONCLUSIONS: Exposure to styrene would impair colour vision even if the exposure concentration was lower than 10 ppm. Furthermore, if the maximum concentration of styrene exposure transiently exceeded 50 ppm in the past, the styrene related damage might remain. Thus, the safe limit of exposure to styrene and the relation between exposure to styrene and the degree of damage to ocular structure, retina, optic nerve, and brain need to be re-examined.

Adult↗
PubMed2002

[Intrapleural streptokinase-streptodornase in the treatment of empyema and hemothorax].

Fourteen of 15 patients (93%) with retained pleural collections underwent successful enzymatic debridement and tube drainage with streptokinase-streptodornase (SK-SD) injections. No significant adverse reactions occurred. One patient required decortication when SK-SD therapy failed. Intrapleural SK-SD is a safe, effective means of removing retained proteinaceous collections in the pleural space. It may obviate the need for more invasive procedures.

Adolescent↗
PubMed2002

Plasma hepatocyte growth factor levels after open heart surgery for congenital heart disease.

BACKGROUND: Hepatocyte growth factor (HGF) is a polypeptide which acts protectively against endothelial cell dysfunction. A high plasma level of HGF is shown when the endothelium is injured. We measured plasma HGF levels during and after open heart operations for congenital heart disease, to elucidate its involvement with endothelial cell injury. METHODS EXPERIMENTAL DESIGN: prospective study. SETTING: perioperative setting. PATIENTS: 18 children electively operated upon for congenital heart disease using CPB. RESULTS: Plasma HGF levels (ng/ml) before cardiopulmonary bypass (CPB) were 0.36+/-0.07 in 10 children (S-group) who were older and with simpler diseases, and 0.48+/-0.12 in 8 children (C-group) who were younger and with relatively complex diseases. HGF levels significantly increased after CPB, and gradually decreased thereafter. Plasma HGF levels 3 and 6 hours after CPB were significantly greater in the C-group than in the S-group (1.13+/-0.12 vs 1.68+/-0.1 6 3 hours after, and 1.09+/-0.19 vs 2.35+/-0,43 6 hours after; p<0.05 for both). There were significant positive correlations between HGF levels 6 hours after CPB and the duration of the CPB, the aortic crossclamping time, and plasma thrombomodulin levels just after CPB in all patients (p<0.05 for all). CONCLUSIONS: This data suggests that increased HGF levels are associated with endothelial cell injury induced by CPB, and that the increases are much greater in younger patients with complex anomalies.

Biomarkers↗
PubMed2001

Polyamines in prostatic epithelial cells and adenocarcinoma; the effects of androgen blockade.

BACKGROUND: Recent identification of eosinophilic prostatic secretory granules (PSG) as the major secretory mechanism of the prostate gland and their loss in neoplasia has prompted scrutiny of their chemical constituents. Polyamines, in particular spermine and spermidine (sp/spd) are the major cations found within prostatic secretions, yet their secretory mechanism in normal and neoplastic tissues has not been investigated. METHODS: Normal prostatic tissues and adenocarcinoma from intact and chemically castrated men were preserved in a glutaraldehyde-based fixative (Solufix((R))). Immunostains for sp/spd were performed before and after harsh acid hydrolysis whereby all protein was removed from tissue sections. RESULTS: Sp/spd immunoreactivity correlated with PSG as recognized in routine stains in tissues from intact patients before and after acid digestion. Decrease in sp/spd in untreated carcinomas was directly related to loss of PSG. After chemical castration, normal glands were mostly devoid of sp/spd while surviving malignant cells stained positively, despite a significant reduction or absence of PSG. Similarly, cancers progressing after castration were intensely decorated with anti-spermine, despite an almost complete loss of PSG. Cytoplasmic sp/spd staining of these androgen resistant clones was in contrast to normal glands no longer acid resistant. CONCLUSIONS: The intense eosinophilia of PSG is attributable to polyamines. Androgen blockade arrests sp/spd production in normal tissue. In contrast, sp/spd production continues in androgen resistant tumor clones, thereby uncoupling polyamines from their normal androgen dependent environment.

Adenocarcinoma↗
PubMed2001

Derivatization of fullerene dimer C120 by the Bingel reaction and a 3He NMR study of 3He@C120 monoadducts.

Cyclopropanation with diethyl bromomalonate and base (the Bingel reaction) was conducted on fullerene dimer C120 to give a mixture of "monoadducts" (45% yield) and "bisadducts" (< or =37% yield), while 18% of the C120 remained unchanged. The "monoadducts" were separated into five positional isomers, i.e., e(face), e(edge), trans-4, trans-3, and trans-2, by preparative HPLC. Assignments were made based on 1H (and 13C) NMR and confirmed by theoretical calculations of the addends' 1H NMR chemical shifts. The relative yields of these isomers were in fair agreement with those observed for the Bingel bisaddition of C60. The Bingel reaction was also carried out on the dimer C120 encapsulating 3He in one of the C60 cages. Each positional isomer of the "monoadduct" exhibited a pair of 3He NMR signals corresponding to an isomer with functionalization on the 3He-containing cage and the other isomer with functionalization on the empty cage. Using the 3He NMR spectroscopy, a pair of signals for the trans-1 isomer, which eluded detection by 1H NMR, were observed, in addition to pairs of signals for e(face), e(edge), trans-4, trans-3, and trans-2 isomers. The 3He NMR signals for isomers with functionalization on the 3He-containing cage were spread out over a 1.82-ppm range reflecting the direct effects of the addition pattern on the C60 surface. In contrast, the isomers with functionalization on the empty cage exhibited 3He NMR signals that appeared over a 0.14-ppm range, which was shown to be primarily due to changes in the diamagnetism of the functionalized cage based on theoretical calculations of 3He NMR chemical shifts for the model system in which the C60 cage encapsulating 3He was removed.

Journal Article↗
PubMed2001

Tumor-specific cytotoxic T lymphocyte responses against chondrosarcoma with HLA haplotype loss restricted by the remaining HLA class I allele.

Although loss of HLA expression by malignant cells has also been demonstrated, it has not been clarified how the loss of HLA expression observed in vitro actually results in immune escape. We demonstrated two major findings: (i) a part of chromosome 6 coding for HLA haplotypes was deleted from the genome of chondrosarcoma cell line, OUMS-27; furthermore, immunohistostaining for HLA-A11 showed that the original chondrosarcoma tissue lost the expression of HLA-A11, implicating that HLA haplotype loss was already present in the original tumor tissue and (2) HLA class I-restricted and autologous tumor-specific cytotoxic T cells (CTL) were generated from peripheral blood lymphocytes of the patient with chondrosarcoma, from whom OUMS-27 originated. This CTL line was maintained by weekly stimulation with OUMS-27, and lysed OUMS-27 in an HLA-A24 dependent manner but did not either K562 or autologous (EBV)-transformed B cells. These observations indicated that OUMS-27 and its original tumor are still immunogenic and can present antigen peptides with the remaining HLA-A24, even if HLA expression is partially lost. Tumor specific immunotherapy can be applied to the treatment of malignancies, even if HLA expression is partially lost.

Aged↗
PubMed2001

Purification, characterization, and cDNA cloning of lipoate-activating enzyme from bovine liver.

In mammals, lipoate-activating enzyme (LAE) catalyzes the activation of lipoate to lipoyl-nucleoside monophosphate. The lipoyl moiety is then transferred to the specific lysine residue of lipoate-dependent enzymes by the action of lipoyltransferase. We purified LAE from bovine liver mitochondria to apparent homogeneity. LAE activated lipoate with GTP at a 1000-fold higher rate than with ATP. The reaction absolutely required lipoate, GTP, and Mg(2+) ion, and the reaction product was lipoyl-GMP. LAE activated both (R)- and (S)-lipoate to the respective lipoyl-GMP, although a preference for (R)-lipoate was observed. Similarly, lipoyltransferase equally transferred both the (R)- and (S)-lipoyl moieties from the respectively activated lipoates to apoH-protein. Interestingly, however, only H-protein carrying (R)-lipoate was active in the glycine cleavage reaction. cDNA clones encoding a precursor LAE with a mitochondrial presequence were isolated. The predicted amino acid sequence of LAE is identical with that of xenobiotic-metabolizing/medium-chain fatty acid:CoA ligase-III, but an amino acid substitution due to a single nucleotide polymorphism was found. These results indicate that the medium-chain acyl-CoA synthetase in mitochondria has a novel function, the activation of lipoate with GTP.

Acyltransferases↗
PubMed2001

Cervical spondylotic amyotrophy with intramedullary cavity formation.

STUDY DESIGN: A case report. OBJECTIVE: To show that an intramedullary lesion was the cause of cervical spondylotic amyotrophy. SUMMARY OF BACKGROUND DATA: Cervical spondylotic amyotrophy is the clinical syndrome characterized by muscle wasting and weakness in the upper extremities without a remarkable sensory loss or spastic tetraparesis. It is still unclear whether the ventral roots or the anterior horn are selectively damaged. METHODS: Magnetic resonance imaging and delayed computed tomographic myelography were performed on a patient who showed severe wasting of the left triceps muscle without any sensory disturbance or long tract sign. RESULTS: On sagittal magnetic resonance images, a linear area was noted within the spinal cord at C6 and C7 spinal segments, which showed low signal intensity on T1-weighted image and high signal intensity on T2-weighted image. On axial T1-weighted image intramedullary low signal intensity area was observed, which was located in the left anterior horn. On axial T2-weighted image the area showed high signal intensity. A delayed (6 hours) computed tomographic scan after intrathecal injection of metrizamide revealed intramedullary enhancement in the area corresponding to the left anterior horn, which would represent cavitation or cystic necrosis. CONCLUSIONS: This is the first case report of cervical spondylotic amyotrophy, in which intramedullary lesion was confirmed only at the affected side of the spinal cord.

Arm↗
PubMed2001

Rho-kinase--mediated contraction of isolated stress fibers.

It is widely accepted that actin filaments and the conventional double-headed myosin interact to generate force for many types of nonmuscle cell motility, and that this interaction occurs when the myosin regulatory light chain (MLC) is phosphorylated by MLC kinase (MLCK) together with calmodulin and Ca(2+). However, recent studies indicate that Rho-kinase is also involved in regulating the smooth muscle and nonmuscle cell contractility. We have recently isolated reactivatable stress fibers from cultured cells and established them as a model system for actomyosin-based contraction in nonmuscle cells. Here, using isolated stress fibers, we show that Rho-kinase mediates MLC phosphorylation and their contraction in the absence of Ca(2+). More rapid and extensive stress fiber contraction was induced by MLCK than was by Rho-kinase. When the activity of Rho-kinase but not MLCK was inhibited, cells not only lost their stress fibers and focal adhesions but also appeared to lose cytoplasmic tension. Our study suggests that actomyosin-based nonmuscle contractility is regulated by two kinase systems: the Ca(2+)-dependent MLCK and the Rho-kinase systems. We propose that Ca(2+) is used to generate rapid contraction, whereas Rho-kinase plays a major role in maintaining sustained contraction in cells.

Calcium↗
PubMed2001

Apoptosis in dissociation between DNA synthesis and cellular functions of activated hepatic stellate cells--a study with carbon tetrachloride-induced rat liver injury.

It is widely believed that DNA synthesis and expressions of smooth muscle alpha actin and TGF-beta are all together increased in activated hepatic stellate cells both in vitro and in vivo. Our previous reports disclosed that these increases did not always coexist under experimental conditions. Liver necrosis was induced in rats by oral administration of carbon tetrachloride. Hepatic stellate cells were isolated from these rats 2 days later. When these cells were cultured on plastic dishes for 3 days, they showed marked DNA synthesis and smooth muscle alpha actin and TGF-beta mRNA expressions assessed by (3)H-thymidine incorporation and Northern blotting, respectively. In the cells further cultured for 7 days, the DNA synthesis was decreased, whereas both smooth muscle alpha actin and TGF-beta mRNA expressions were increased, compared to the cells cultured for 3 days. The cells cultured for 10 days showed apoptotic nuclei positive for nick-end labeling, and DNA extracted from the cells revealed laddering patterns on agarose gels by electrophoresis. Apoptotic nuclei were also immunohistochemically found in stellate cells in the liver of rats 4 days after the intoxication. We conclude that apoptosis developed in activated hepatic stellate cells both in vitro and in vivo, and this may contribute to the discrepancy between DNA synthesis and cellular functions of the cells.

Actins↗
PubMed2001

Evaluation of glass microspheres for intra-arterial radiotherapy in animal kidneys.

PURPOSE: To evaluate the histologic distribution of nonradioactive microspheres when intra-arterially infused into normal kidneys, and to evaluate the histologic changes after the infusion. MATERIALS AND METHODS: The glass microspheres were SiO2 microspheres with a smooth spherical shape measuring 20-30 micrometers in diameter with a specific gravity of 2.2 g/cm3. After the microspheres were mixed with contrast medium, they were infused into the renal artery. Twelve rabbits were sacrificed at 1 day, 3 days, 1 week, and 8 weeks after the treatment, respectively. The specimen was fixed with 10% buffered formalin, specially embedded in methyl methacrylate (MMA) resin and was stained by hematoxylin-eosin. The distribution of the microspheres in the kidney was analyzed microscopically, and histologic changes were also evaluated. RESULTS: The microspheres were found in arterioles whose diameters were about 20-30 micrometers, within normal kidneys. All vessels containing microspheres were confined to arterioles or arteries. No migration of microspheres was detected in the normal lung or the contralateral kidney. Severe ischemic changes were observed in kidneys, developing within 8 weeks of the infusion. CONCLUSION: Glass microspheres seemed to be a useful embolic material for intra-arterial radiation therapy.

Animals↗
PubMed2001

Functional roles of ionic and hydrophobic surface loops in smooth muscle myosin: their interactions with actin.

This investigation ascertains whether, in (smooth muscle) myosin, certain residues engage in functional interactions with their actin conjugates in an actomyosin complex. Such interactions have been postulated from putting together crystallographic models of the two proteins [Rayment, I., Rypniewski, W. R., Schmidt-Bäse, K., Smith, R., Tomchick, D. R., Benning, M. M., Winkelmann, D. A., Wesenberg, G., and Holden, H. M. (1993) Science 261, 50-58]. Here, in several instances, we ask whether mutation of a particular residue significantly impairs a function, and find that the answers are largely rationalized by the original postulation. Additionally, a novel element emerges from our investigation. To assess function, we test the wild type and mutant systems as they perform in the steady state of ATP degradation. In doing so, we assume, as usual, that degradation proceeds from an early stage in which the complex forms (and is described by parameter K(app)) to a later stage during which the product leaves the complex (and is described by parameter V(max)). Interestingly, certain defects induced by the mutations are associated with changes in K(app), and other defects are associated with changes in V(max), suggesting that our procedure at least roughly distinguishes between events according to the time in the degradation at which they occur. In this framework, we suggest that (1) in the actin-myosin association phase, cationic residues Lys-576 and Lys-578 interact with anionic residues of the so-called second actin, and (2) in the product leaving phase, hydrophobic residues Trp-546, Phe-547, and Pro-548, as well as the Thr-532/Asn-533/Pro-534/Pro-535 sequence, sever connections with the so-called first actin. The role of Glu-473 is also examined.

Actins↗
PubMed2001

VEGF can act as vascular permeability factor in the hepatic sinusoids through upregulation of porosity of endothelial cells.

VEGF is shown to be a vascular permeability factor (VPF) as well as a growth stimulatory factor on endothelial cells. In the hepatic sinusoids, endothelial cells express flt-1 and KDR/flk-1, receptors for VEGF. These cells, in primary culture, proliferate in response to VEGF stimulation. However, the role of VEGF as VPF in the hepatic sinusoids is to be elucidated. The effect of VEGF on the porosity of sinusoidal endothelial cells was studied. Sinusoidal endothelial cells were isolated from rats and cultured in DMEM containing 10% FCS on plastic dishes coated with type I collagen for 16 and 48 h for morphological examination and cell-number measurement, respectively. When the cells were cultured without VEGF addition, their number was decreased at 48 h compared to that at 16 h. However, the number was unchanged in the cells cultured with VEGF at 10 ng/mL and increased with addition of VEGF at 100 ng/mL. Scanning electron microscopic examination revealed that sieve-plate appearance of the cells was impaired in culture with no VEGF addition, but the appearance was maintained in culture with VEGF at 10 ng/mL or more. The cells cultured with VEGF at 100 ng/mL showed significantly increased number and size of pores compared to the cells cultured with VEGF at 10 ng/mL, suggesting that sinusoidal endothelial cells proliferating in response to VEGF may increase their porosity. It is concluded that VEGF can act as VPF in the hepatic sinusoids through regulation of endothelial cell porosity.

Animals↗
PubMed2001

Induction of primary root curvature in radish seedlings in a static magnetic field.

Primary roots of radish (Raphanus sativus L.) seedlings were exposed to an inhomogeneous static magnetic field generated by a permanent magnet, during continuous rotation on a 0.06 rpm clinostat, thereby reducing the unilateral influence of gravity. The roots responded tropically to the static magnetic field with the tropism appearing to be negative. These roots responded significantly (P < 0.05) to the south pole of the magnet. The significant tropic response was found for a magnetic flux density of 13-68 mT, for a field gradient of 1.8-14.7 T/m, and for the product of magnetic field and field gradient of 0.023-1.0 T(2)/m. A small, but insignificant, response of the roots to the north pole has also been found.

Brassicaceae↗
PubMed2001

Incomplete atrioventricular septal defect with hypoplastic left ventricle and left atrioventricular valve stenosis.

A 2-month-old male infant with incomplete atrioventricular septal defect associated with a hypoplastic left ventricle and left atrioventricular valve stenosis successfully underwent biventricular repair. Echocardiography showed marked dilatation in the right ventricle and a diminutive left ventricle. However, the left ventricular chamber occupied the apex. Left atrioventricular valve stenosis was due to a solitary papillary muscle. Cardiac catheterization showed pulmonary/systemic flow ratio of 3.61, left ventricular end-diastolic volume of 63% of normal, and right ventricular end-diastolic volume of 324% of normal. During surgical repair, the solitary papillary muscle was divided longitudinally and the ostium primum was closed with a bovine pericardium. Postoperative left ventricular function was appropriate. Even when the preoperative end-diastolic left ventricular volume is small, if the left ventricle chamber is at the apex, then the left ventricular performance can be expected to be appropriate to tolerate the volume load after ostium primum closure.

Heart Septal Defects, Atrial↗