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Biomedical subjects

M Arai

Publications and source records attributed to M Arai.

At least 217 records · Page 12Linked to original sources
PubMed1998

Expression of Aspergillus aculeatus No. F-50 cellobiohydrolase I (cbhI) and beta-glucosidase 1 (bgl1) genes by Saccharomyces cerevisiae.

A cellobiohydrolase I (cbhI) and a beta-glucosidase 1 (bgl1) gene of Aspergillus aculeatus were expressed in Saccharomyces cerevisiae. The transformed cells secreted the enzymes efficiently in an active form. The recombinant CBHI gave two bands of different molecular mass (110 and 90 kDa) and the recombinant BGL1 gave one band (180 kDa) by SDS-PAGE. The recombinant CBHI and BGL1 had the same enzymatical properties as the native enzyme except for the specific activity toward cellulosic substrates. By the combination of three different types of cellulases, FI-CMCase, CBHI, and BGL1, we could hydrolyze Avicel up to 59% under our experimental conditions.

Aspergillus↗
PubMed1998

Involvement of vitamin D in lead-induced cutaneous calcification in rodents.

Experimental cutaneous calcification was induced by a subcutaneous injection of lead acetate in parathyroidectomized (PTX) rats and vitamin D-deficient rats whose plasma calcium concentrations were controlled by diets containing various amounts of calcium. Although, in PTX rats, the calcium content of the calcified plaque induced by lead acetate was correlated with their plasma calcium concentration, calcium content of the calcified plaque in vitamin D-deficient rats with normocalcemia was significantly lower than those in control and PTX rats with normocalcemia. A subcutaneous administration of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) following the lead acetate injection increased calcium content of the calcified plaque in vitamin D-deficient mice, suggesting the involvement of vitamin D in the cutaneous calcification. As the synthesis of osteocalcin, osteopontin and interleukin-1 (IL-1) receptor is well known to be increased by 1 alpha,25(OH)2D3, gene expressions of mRNAs of these proteins were examined in the skin with calcified plaque by reverse transcription polymerase chain reaction (RT-PCR) analysis. These mRNA expressions in the skin with calcified plaque were increased by a subcutaneous administration of 1 alpha,25(OH)2D3 following the lead acetate injection. On the contrary, they decreased in vitamin D-deficient mice. These findings suggest that vitamin D is directly involved in the process of experimental calcification.

Animals↗
PubMed1998

Bilateral coronary ostial stenosis and aortic regurgitation due to syphilitic aortitis.

Coronary ostial stenosis in otherwise normal coronary vessels, is a rare complication of syphilitic aortitis, and most of the cases are found at autopsy. We report here a case in which bilateral coronary ostial stenosis and aortic regurgitation due to syphilitic aortitis was diagnosed; coronary artery bypass graft and aortic valve replacement were then performed. The macroscopic finding and the histopathological examination of the ascending aorta revealed the presence of syphilitic aortitis. It is important to note that syphilis is one of the causes of coronary ostial stenosis in young adults associated with aortic regurgitation.

Adult↗
PubMed1998

Morphometric study of skin grooves of the head and neck.

The skin surface contains furrows called wrinkles, Langer's lines, and skin grooves that are characteristic ultrastructures of the skin. When a skin incision line is determined, these features should be considered. Many studies have examined skin wrinkles, the number of which increases with age. Langer's lines have also been studied extensively in cadavers. However, these studies may not consistently reflect Langer's lines in living individuals. Most of the studies of skin grooves have examined dermatoglyphics such as fingerprinting, palm printing, and sole printing. Very few studies have examined skin grooves in other areas or quantified their characteristics. The present study analyzed skin grooves of the head and neck in relationship to age, sex, and region. Subjects consisted of 50 nursery school children aged 6 years, 50 college students aged 20 years, and 50 adults aged over 60 years. Impressions were obtained from: 1) forehead, 2) root of the nose, 3) lateral ocular angle, 4) cheek, and 5) neck. The samples were cut into cubes (5.0 x 5.0 x 1.0 mm) and ion-coated with Au-Pdin by a cool sputter coater. Then scanning electron micrographs (x 50) were taken and analyzed by computer morphometry CB-TASPER. Densities of skin grooves and the specific length representing the complexity of grooves per unit area were analyzed using computer morphometry CB-TASPER software. The density of skin grooves differed according to the area, especially among samples taken from the forehead, root of the nose, and the neck. Females had more grooves than males, particularly in the neck region. Skin grooves decreased with age; they appear to change and be absorbed by increasing wrinkles, thus becoming indistinct.

Adult↗
PubMed1998

Impaired expression of atrial natriuretic peptide in diabetic rats with myocardial infarction.

We evaluated the effects of myocardial infarction (MI) on the hemodynamics and the expression of atrial natriuretic peptide (ANP) mRNA in rats with streptozotocin-induced diabetes. Eight weeks after streptozotocin injection, the diabetic rats and age-matched nondiabetic controls underwent coronary artery ligation. One week later, the left ventricular end-diastolic pressure, systolic blood pressure, infarct size, and serum ANP levels did not differ significantly between the diabetic and nondiabetic rats. Compared with control animals without MI, the atrial ANP/beta-actin mRNA ratio in rats with MI was increased to 195% in diabetic animals and 213% in nondiabetic animals. In the left ventricle, however, the ANP/beta-actin mRNA ratio in diabetic animals with MI was increased to only 131% compared with control animals, whereas the corresponding increase in nondiabetic animals was 240% (p<0.05). Thus, the modulation of ANP mRNA expression after MI was impaired in the left ventricle, but not in the atria, of diabetic rats. A reduced myocardial expression of ANP could increase the morbidity and mortality associated with cardiovascular disorders in patients with diabetes.

Animals↗
PubMed1998

[A case of Guillain-Barré syndrome associated with bilateral ballism: an overlap between Fisher's syndrome and Guillain-Barré syndrome].

A 29-year-old woman developed diplopia and ataxic gait. Neurological examination revealed total ophthalmoplegia, cerebellar ataxia, and areflexia. Muscle weakness in four limbs was also noted. We diagnosed the patient as having an overlap between Fisher's syndrome and Guillain-Barré syndrome. On day 5, she suddenly had flinging involuntary movements affecting the face and four extremities. Surface EMG recording revealed 1.5- 2 Hz rhythmic grouping discharges. The involuntary movements were considered as ballism. Brain CT and MRI could not detect any abnormal findings in subthalamic nucleus, but, electrophysiological findings revealed CNS lesions. Therefore, the clinical diagnosis also were Bickerstaff's brainstem encephalitis. She had high titer of IgG antibody to GQ 1b (1:64,000). Sera taken from patients with Fisher's syndrome, Guillain-Barré syndrome with ophthalmoparesis and Bickerstaff's brainstem encephalitis during the acute phases of these syndromes frequently have IgG antibody to GQ 1b ganglioside. It is concluded that some cases of acute ophthalmoparesis subsequent to infection or immunization may be categorized as autoimmune diseases. Hence, such disease which show external ophthalmoparesis may be designated the "anti-GQ 1 b IgG antibody syndrome". This is the first report on the patient with Guillain-Barré syndrome and the related disorders who showed ballism.

Adult↗
PubMed1997

Nicorandil reduces myocardial infarct size by opening the K(ATP) channel in rabbits.

UNLABELLED: We examined whether nicorandil reduces myocardial infarct size (1) when administered before ischemia, and (2) when administered before reperfusion, and whether (3) infarct size is influenced by the plasma nicorandil concentration and the opening of the K(ATP) channel. Anesthetized open-chest Japanese white male rabbits were subjected to a 30 min coronary occlusion (ischemia) and a 48 h reperfusion in the following six groups; Group 1 (n=9): control group, Group 2 (n=9): pre-ischemia to post-reperfusion group (nicorandil 10 microg/kg/min, i.v.), Group 3 (n=7): pre-ischemia to post-reperfusion+glibenclamide group (glibenclamide 0.3 microg/kg, i.v.+nicorandil 10 microg/kg/min, i.v.), Group 4 (n=8): pre-reperfusion to post-reperfusion group (nicorandil 10 microg/kg/min, i.v.), Group 5 (n=8): pre-ischemia low-dose group (nicorandil 10 microg/kg/min for 5 min i.v.), Group 6 (n=7): pre-ischemia high-dose group (nicorandil 100 microg/kg/min for 5 min i.v.). The plasma nicorandil concentrations were measured from blood samples taken immediately before the ischemia. After the 48 h reperfusion, the size of the infarct was measured histologically with immunohistochemical actin staining and expressed as a percentage of the area at risk. RESULTS: Infarct sizes were as follows; Group 1 (control): 41.0+/-3.5%, Group 2: 31.3+/-2.0% (P<0.05 vs. control), Group 3: 40.9+/-3.4%, Group 4: 45.2+/-4.4%, Group 5: 35.8+/-3.3%, Group 6: 25.2+/-3.9% (P<0.05 vs. control). Infarct size was inversely correlated with the plasma nicorandil concentrations (y=-0.031x+41.0, r=0.65, P<0.05). CONCLUSIONS: The pre-ischemic but not post-ischemic administration of nicorandil reduced the size of myocardial infarct by opening the K(ATP) channels, and this effect was dependent on the plasma nicorandil concentrations immediately before the ischemia induced in rabbits.

Analysis of Variance↗
PubMed1997

Expression of mRNAs for neuropeptide receptors and beta-adrenergic receptors in human osteoblasts and human osteogenic sarcoma cells.

In human periosteum-derived osteoblastic cells (SaM-1) and human osteosarcoma-derived cells (SaOS-2, HOS, MG-63), the mRNA expressions of calcitonin gene-related peptide receptor (CGRP-R), substance P receptor (SP-R), neuropeptide Y receptor (NPY-R), beta-adrenergic receptors (beta1-R, beta2-R, beta3-R), vasoactive intestinal polypeptide type 1 and type 2 receptors (VIP-1R, VIP-2R) and pituitary adenylate cyclase activating polypeptide receptor (PACAP-R) were examined by reverse transcription-polymerase chain reaction (RT-PCR). According to the magnitude of the mRNA expression of alkaline phosphatase (ALP), the relative state of commitment of these osteoblastic cell lines to the osteoblast lineage was SaM-1 > SaOS-2 > HOS > MG-63. CGRP-R, NPY-R, VIP-1R and beta2-R, but not SP-R, VIP-2R, PACAP-R, beta1-R and beta3-R, were expressed in osteoblasts as well as osteosarcoma cells. Expression of these receptors seems to be a common feature in osteoblastic cells, but the magnitude of expression was not dependent upon the relative state of commitment of the osteoblastic cells to the osteoblast lineage. In addition, VIP mRNA was not expressed in osteoblastic cells, suggesting the absence of an autocrine system of VIP in osteoblasts. These observations suggest that these neuropeptides and norepinephrine are involved in local regulation of human bone metabolism.

Adult↗
PubMed1997

A novel association of Fc receptor gamma-chain with glycoprotein VI and their co-expression as a collagen receptor in human platelets.

The mechanism by which occupancy of collagen receptors is coupled to platelet activation has been uncertain. Our group previously demonstrated that glycoprotein (GP) VI, an uncharacterized platelet membrane protein, is specifically required for collagen-platelet interaction leading to activation of protein-tyrosine kinase Syk. Since collagen stimulation of platelets has recently been found to induce tyrosine phosphorylation of Fc receptor (FcR) gamma-chain, a signal-generating subunit of FcR, we further investigated the relationships between FcR gamma-chain and GPVI in human platelets. Our present study revealed the following. FcR gamma-chain was physically and stably associated with GPVI in human platelets; both FcR gamma-chain and GPVI were proportionally absent in GPVI-deficient platelets; GPVI cross-linking or collagen stimulation of platelets resulted in tyrosine phosphorylation of GPVI-associated FcR gamma-chain accompanied by Syk association and activation. These findings strongly suggest that the associated complex of GPVI and FcR gamma-chain is a collagen receptor featuring the signaling through immune receptors.

Blood Platelets↗
PubMed1997

Resistance to fas-mediated apoptosis of peripheral T cells in human T lymphocyte virus type I (HTLV-I) transgenic mice with autoimmune arthropathy.

Transgenic mice carrying the env-pX region of human T lymphocyte virus type I (HTLV-I) develop autoimmune arthropathy in high incidence. Adopting the approach that Fas-mediated apoptosis has a critical function in the elimination of self-reactive T cells, we examined the involvement of this apoptosis in the induction of autoimmunity in HTLV-I transgenic mice. Splenic T cells derived from the transgenic mice were more resistant to apoptosis induced by anti-Fas mAb than those of the nontransgenic mice, whereas no appreciable difference in apoptosis was detected for thymocytes from either mouse's type. The resistance of transgenic T cells may be due to Tax coded in the pX region, since Tax mediates the inhibition of anti-Fas- induced apoptosis in mature T cell line, Jurkat. Among the transgenic mice, the extent of the resistance to Fas-mediated apoptosis was further enhanced in transgenic T cells with disease. These results suggest that the escape of self-reactive T cells from Fas-mediated apoptosis in the periphery, is critical for the development of autoimmune arthropathy in HTLV-I transgenic mice.

Animals↗
PubMed1997

The Promotion of Alkaline Fading of Crystal Violet by AOT Micelles Dispersed in Supercritical Ethane Medium

The alkaline fading of crystal violet (CV) is accelerated by using a w/o microemulsion of H2 O/AOT/ethane under supercritical conditions. The rate of fading can be changed by three orders of magnitude with the molar ratio of water to AOT and operating pressure. The highest rate of CV fading observed is larger by a factor of 100 or more compared to those reported so far in the literature. The structure of AOT molecules and the type of interior water molecules seem to account for the rate enhancement with an increase in the water/AOT molar ratio. It is suggested that the intermicellar and AOT-ethane interactions are of significance for the promotion effect of pressure.

Journal Article↗
PubMed1997

Preferential esterification of endogenously formed 5-hydroxyeicosatetraenoic acid to phospholipids in activated polymorphonuclear leukocytes.

The esterification of endogenously formed 5-hydroxyeicosatetraenoic acid (5-HETE) to cellular lipids in rat polymorphonuclear leukocytes (PMNL) was studied quantitatively by a fluorometric method using HPLC. Rapid and maximal production of free 5-HETE was observed after a 5-min stimulation of PMNL with A23187. The amount of free 5-HETE then declined rapidly, while that of 5-HETE esterified to phospholipids and triacylglycerol concomitantly increased in a time-dependent manner. Stimulation by A23187 yielded approximately 100 ng/10(7) cells esterified 5-HETE in 60 min, which corresponded to the decrease in the amount of free 5-HETE from 5 min to 60 min and indicated that free 5-HETE, which was formed endogenously, was metabolized predominantly by esterification to cellular lipids. The esterification profile of exogenous 5-HETE was different from that of endogenous 5-HETE. 5-[3H]HETE, which was added exogenously to the culture medium, was rapidly incorporated into PMNL and almost 80% of the total radioactivity was located in triacylglycerol. A quantitative study revealed that endogenous 5-HETE was esterified equally to phospholipids and triacylglycerol. Like PMNL, peritoneal macrophages treated with A23187 released significant amounts of 5-HETE. However, less 5-HETE was esterified to cellular lipids than in PMNL. Negligible amounts of 12-HETE, produced by activated peritoneal macrophages or activated platelets after a challenge with A23187, were esterified during the entire incubation. Exogenous 5-HETE was rapidly taken up by PMNL, but was incorporated into macrophages much more slowly than into PMNL. No uptake of 12-HETE into macrophages was observed. The rapid uptake of exogenous 5-HETE was strongly inhibited by the suppression of acylation of 5-HETE by triacsin C. These results suggest that esterification might be one of the factors that regulate the rate of incorporation of 5-HETE.

Animals↗
PubMed1997

The Nature and Structure of Water/AOT/Ethane (W/O) Microemulsion under Supercritical Conditions Studied by High-Pressure FT-IR Spectroscopy

High-pressure FT-IR spectroscopy was used to study a W/O microemulsion system of AOT micelles dispersed in supercritical ethane. The system was found to be in a single-phase state depending on the pressure (P), temperature (T), and water-to-AOT molar ratio (W0). The number of water molecules that the AOT micelles were able to solubilize reached about 15 at 35.0 MPa and 343.1 K. This presents a striking contrast to AOT micelles in ordinary organic liquids, in which the number of solubilized water molecules ranges from 2 to 6. The solubilized water molecules were present in three different types and their relative quantities depended on W0, P, and T. The presence of trans-like and/or gauche-like AOT isomers also depended on the operating variables, which affected the interactions between AOT molecules and the water molecules solubilized in them. The solubilization of water and the rotational isomerism of AOT were significantly influenced in different ways by the addition of salts, including lithium chloride, guanidine hydrochloride, and cesium iodide.

Journal Article↗
PubMed1997

Mutations of the Ki-ras, p53 and APC genes in adenocarcinomas of the human small intestine.

In contrast to the origins of colorectal carcinomas, the mechanisms of carcinogenesis in the small intestine remain unclear. We therefore analyzed the mutational status of the Ki-ras, p53, and adenomatous polyposis coli (APC) genes in primary carcinomas of the small intestine and compared the mutation patterns with those established for colorectal cancers. DNA was extracted from 15 formalin-fixed, paraffin-embedded lesions. Codons 12, 13 and 61 of the Ki-ras gene, exons 5-8 of the p53 gene, and codons 1268-1569, which contain the mutation cluster region (MCR) of the APC gene, were amplified by means of PCR, subcloned and sequenced. Mutations of the Ki-ras and p53 genes were observed in 8 (53.3%) and 4 lesions (26.7%), respectively. The mutational frequency of the Ki-ras gene in the present series of small intestinal carcinomas was similar, while that of the p53 gene was slightly lower than the reported frequencies for colorectal carcinomas. Only one case showed a mutation of the APC gene, involving an insertional mutation of an adenine at codons 1554-1556 with formation of a stop codon immediately downstream. Since the occurrence of an APC mutation is considered an early event in colorectal carcinogenesis, our findings indicating an extremely low frequency of such changes in and around the MCR suggest that carcinomas of the small intestine arise via a genetic pathway distinct from that involved in the development of carcinomas of the colorectum.

Adult↗
PubMed1997

Collagen-stimulated activation of Syk but not c-Src is severely compromised in human platelets lacking membrane glycoprotein VI.

Activation of circulating platelets by subendothelial collagen is an essential event in vascular hemostasis. In human platelets, two membrane glycoprotein (GP) abnormalities, integrin alpha2 beta1 deficiency and GPVI deficiency, have been reported to result in severe hyporesponsiveness to fibrillar collagen. Although it has been well established that integrin alpha2 beta1, also known as the GPIa-IIa complex, functions as a primary platelet adhesion receptor for collagen, the mechanism by which GPVI contributes to collagen-platelet interaction has been ill defined to date. However, our recent observation that GPVI cross-linking couples to cyclic AMP-insensitive activation of c-Src and Syk tyrosine kinases suggested a potential role for GPVI in regulating protein-tyrosine phosphorylation by collagen (Ichinohe, T., Takayama, H., Ezumi, Y., Yanagi, S., Yamamura, H., and Okuma, M. (1995) J. Biol. Chem. 270, 28029-28036). To further investigate this hypothesis, here we examined the collagen-induced protein-tyrosine phosphorylation in GPVI-deficient platelets expressing normal amounts of alpha2 beta1. In response to collagen, these platelets exhibited alpha2 beta1-dependent c-Src activation accompanied by tyrosine phosphorylation of several substrates including cortactin. In contrast, severe defects were observed in collagen-stimulated Syk activation and tyrosine phosphorylation of phospholipase C-gamma2, Vav, and focal adhesion kinase, implicating a specific requirement of GPVI for recruiting these molecules to signaling cascades evoked by collagen-platelet interaction.

Adult↗
PubMed1997

Comparison of Snellen acuity and objective assessment using the spatial frequency sweep PVER.

BACKGROUND: We compared the vision objectively assessed by spatial frequency sweep pattern-reversal visual-evoked response (SPVER) with the Snellen acuity in patients. METHODS: SPVER acuity and Snellen acuity were measured in 100 patients with various ocular pathologies, including macular diseases, diffuse retinal degeneration, optic nerve diseases, glaucoma, and high myopia. For SPVER, 10 sinusoidally modulated vertical gratings were presented as stimuli. The responses were averaged and displayed through the discrete Fourier transform on the monitor display. The PVER acuity was determined by extrapolating the SPVER amplitude-spatial frequency function to baseline. RESULTS: Vision ranged from 20/15 to 20/400 with Snellen acuity, and from 20/25 to 20/190 with SPVER. The overall correlation between the two acuities was r = 0.666. The correlation varied from r = 0.895 in eyes with glaucoma to r = 0.436 in eyes with optic nerve disease. Seventy-seven eyes (77%) had a visual acuity agreement of within 1.0 octave between the two measurements. CONCLUSION: The SPVER acuity and the Snellen acuity correlated to a certain degree. Discrepancies were found in certain diseases, with the highest disparity in patients with optic nerve disease. We conclude that the SPVER is effective in estimating vision objectively, particularly in patients in whom the standard Snellen test is impossible to perform or yields unreliable results.

Adolescent↗
PubMed1997

Comparison of preferential looking acuity and pattern reversal visual evoked response acuity in pediatric patients.

BACKGROUND: We compared the visual acuities obtained with preferential looking (PL), the most widely used method of pediatric vision assessment, with those obtained with the spatial frequency sweep pattern-reversal visual evoked response (SPVER). METHODS: Eighty patients (ages 1.5 months to 12 years) with various ocular pathologies participated in this study. The PL acuity was determined using the up-and-down staircase procedure. The PVER was recorded with the spatial frequency sweep method using 10 spatial frequencies; the acuity was determined by placing the best-fit regression line on the descending slope of the PVER amplitude-spatial frequency function toward the higher spatial frequency to the baseline. RESULTS: The PL acuities ranged from 20/25 to < 20/1600 (mean 20/155). The correlation between the two methods was good (r = 0.847). Fifty-six patients (70%) had an acuity agreement within 1.0 octave. When the PL acuity was > 20/128, it was on average better than the PVER acuity. When the PL acuity was lower, the PVER acuity was usually better. This tendency was marked when the visual acuities were very poor (y = 0.552x + 0.362). CONCLUSION: The methods correlate well, although there is a dissociation of acuities in the presence of very low vision. PVER may be a useful addition to PL in assessment of vision in infants and young children.

Child↗