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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 91 records · Page 5Linked to original sources
PubMed2000

A 38 kb segment containing the cdc2 gene from the left arm of fission yeast chromosome II: sequence analysis and characterization of the genomic DNA and cDNAs encoded on the segment.

A genomic 38 kbp segment on the c1750 cosmid clone containing the cdc2 gene, located in the left arm of chromosome II from Schizosaccharomyces pombe, was sequenced. The segment was found to have five previously known genes, pht1, cdc2, his3, act1 and mei4. Among 11 coding sequences (CDSs) predicted by the gene finding software INTRON.PLOT., four CDSs, pi007, pi010, pi014 and pi016, had considerable similarity to 40S ribosomal protein, glycosyltransferase, cdc2-related protein kinase and alpha-1, 2-mannosyltransferase, respectively. Another unusually huge open reading frame (ORF) (pi011), consisting of 2233 amino acids, existed, having significant homology to alpha-amylase, granule-bound glycogen synthase and the Sz. pombe YS 1110 clone product at the N-terminal, middle and C-terminal regions, respectively. All the predicted 11 CDSs were experimentally analysed by RACE PCR. The sequencing of the RACE products revealed that there were two small overlaps at the 3' untranslated regions (UTRs) between pi004 and pi005 (17 bp) and between pi007 and pi008 (2 bp). The distances between 5' end of the 5'UTR and the putative translation initiation codon varied from 10 to 302 nucleotides (nt) among the nine CDSs successfully analysed by 5'-RACE. The expression level of each CDS on this clone was determined. Among the 16 genes on this clone, the previously determined genes, pht1, cdc2, his3 and act1, were found to be most highly expressed. Finally, cDNAs of all the newly identified genes were detected by RACE, proving the actual expression of these genes. The nucleotide sequence has been submitted to the EMBL database under Accession No. AB004534.

Base Sequence↗
PubMed2000

Simultaneous analysis of [3H]-thymidine uptake and alpha 1(I) procollagen mRNA expression in systemic sclerosis skin fibroblasts--an in situ hybridization study.

Heterogeneity of DNA synthesis and collagen synthesis has been reported in skin fibroblasts from systemic sclerosis (SSc) patients. The uptake of [3H]-thymidine and expression of alpha 1(I) procollagen mRNA by cultured skin fibroblasts from four normal controls and four SSc patients was analyzed simultaneously. The grains overlying the cytoplasm representing alpha 1(I) procollagen mRNA and overlying the nucleus representing [3H]-thymidine uptake were counted using computer-aided image analysis. The results were analyzed statistically. Procollagen mRNA expression by SSc fibroblasts was significantly greater than by control fibroblasts (P < 0.01). The distribution curve of [3H]-thymidine uptake showed two peaks representing low- and high-uptake cells. Significantly more SSc fibroblasts than control fibroblasts showed high [3H]-thymidine uptake (P < 0.05). The number of SSc fibroblasts expressing low amounts of alpha 1(I) procollagen mRNA was significantly lower than the number of control fibroblasts (P < 0.05). [3H]-thymidine uptake by SSc fibroblasts expressing high amounts of alpha 1(I) procollagen mRNA was significantly lower than by those expressing low amounts (P < 0.05). These results indicate that elevated DNA synthesis and elevated collagen mRNA synthesis in SSc skin fibroblasts are due to different clones with high DNA-synthesizing ability and high collagen-producing ability.

Aged↗
PubMed2000

Midazolam as a first-line agent for status epilepticus in children.

Midazolam is a water-soluble benzodiazepine, and has recently emerged as a safe and effective treatment option after ordinary antiepileptic therapy in the management of status epilepticus. However, midazolam as a first-line agent for status epilepticus in children has not been fully investigated. Intravenous midazolam was used for status epilepticus in 27 children (38 convulsive episodes) from January 1997 to December 1999 in our hospital. Among them, 10 patients (16 convulsive episodes) were treated with intravenous midazolam as a first-line agent. The causes of the seizures varied. Midazolam was administered as an intravenous bolus dose (0.1-0.3 mg/kg), followed by continuous intravenous infusion (1-8 microg/kg per min). In all epileptic episodes but one, the seizures stopped within 1 min without any adverse effects. These results were compatible with the previously reported ones. It is important to terminate status epilepticus which can cause brain damage. Midazolam seems to be effective and safe as a first-line therapy for status epilepticus in children.

Adolescent↗
PubMed2000

Expression of T-cell cytokines in challenged skin of murine allergic contact photosensitivity: low responsiveness is associated with induction of Th2 cytokines.

Murine contact photosensitivity (CPS) to 3,3',4', 5-tetrachlorosalicylanilide (TCSA) is genetically controlled mainly by the major histocompatibility complex. The H-2(b,d) haplotypes are closely associated with high responders, whereas mice with H-2(k) are low or non-responders. We found that BALB/c (H-2(d)) mice were high responders in CPS not only to TCSA but also to chlorpromazine (CPZ) and benzocaine, whereas AKR/n (H-2(k)) mice were hyporesponsive to these three photoallergic agents. To elucidate the relationship between CPS responsiveness and T helper cell induction, the expression of T-cell cytokines was examined by reverse transcriptase polymerase chain reaction in the elicited skin of CPS to the three chemicals. The expression levels of interleukin(IL)-2 and interferon-gamma mRNAs were markedly higer in BALB/c mice than AKR/n mice, whereas mRNA for IL-4 was expressed strongly in AKR/n mice. These data suggest that the hyporesponsiveness of CPS to the photoallergens in AKR/n mice is closely associated with the activation/induction of Th2 cytokines at the challenged sites.

Allergens↗
PubMed2000

Identification and characterization of Clostridium paraputrificum M-21, a chitinolytic, mesophilic and hydrogen-producing bacterium.

A strictly anaerobic, mesophilic and chitinolytic bacterial strain, M-21, was isolated from a soil sample collected from Mie University campus and identified as Clostridium paraputrificum based on morphological and physiological characteristics, and 16S rRNA sequence analysis. C. paraputrificum M-21 utilized chitin and N-acetyl-D-glucosamine (GlcNAc), a constituent monosaccharide of chitin, to produce a large amount of gas along with acetic acid and propionic acid as major fermentation products. Hydrogen and carbon dioxide accounted for 65% and 35% of the gas evolved, respectively. The conditions for 1 l batch culture of C. paraputrificum, including pH of the medium, incubation temperature and agitation speed, were optimized for hydrogen production with GlcNAc as the carbon source. The bacterium grew rapidly on GlcNAc with a doubling time of around 30 min, and produced hydrogen gas with a yield of 1.9 mol H2/mol GlcNAc under the following cultivation conditions: initial medium pH of 6.5, incubation temperature of 45 degrees C, agitation speed of 250 rpm, and working volume of 50% of the fermentor. The dry cell weight harvested from this culture was 2.0 g/l.

Journal Article↗
PubMed2000

Ascorbate regeneration by the reduced form of 2-amino-3-carboxy-1, 4-naphthoquinone, a strong growth stimulator for bifidobacteria.

Nonenzymatic reduction of dehydroascorbate into ascorbate by the reduced form (quinol form) of 2-amino-3-carboxy-1,4-naphthoquinone, a strong growth stimulator for bifidobacteria, has been found. The bimolecular reaction rate constant was evaluated as 9 M(-)(1) s(-)(1) at pH 7.0. This reaction has been successfully coupled with enzymatic regeneration of the naphthoquinol by NAD(P)H in cell-free extracts of Bifidobacterium longum 6001. The overall reaction is a regeneration of NAD(P)(+) by dehydroascorbate [or a regeneration of ascorbate by NAD(P)H], in which the naphthoquinone/quinol redox couple functions as an electron transfer mediator. Kinetic study of the reduction of dehydroascorbate with related quinol compounds suggested the significance of the amino substituent of the naphthoquinol. A mechanism of the electron transfer from the quinol to dehydroascorbate is proposed, where the first step of the reaction is a nucleophilic addition of the C(2)-amino substituent of the naphthoquinol to the C(2)-position of dehydroascorbate to form a Schiff base intermediate.

Ascorbic Acid↗
PubMed2000

Medical markup language (MML) for XML-based hospital information interchange.

Medical Markup Language (MML) has been developed over the last 6 years in order to create a set of standards by which medical data, within Japan and hopefully worldwide, can be stored, accessed and exchanged in any number of physical locates. The MML version 2.21 is characterized by XML as meta-language, module structure for each document and enhancement of linking function among documents. Data exchange specification has been also added for query and reply. MML instances are composed of MML header and MML body. The MML header includes information for data transmission, while MML body includes several module items. One module item contains two elements: document information and module content. Nine MML module contents are defined at the present time: patient information, health insurance information, diagnosis information, lifestyle information, basic clinic information, particular information at the time of first visit, progress course information, surgery record information and clinical summary information.

Clinical Laboratory Techniques↗
PubMed2000

Clear cell odontogenic tumor in the mandible: report of a case with duct-like appearances and dentinoid induction.

A case of clear-cell odontogenic tumor with unusual histological features is presented. A 61-year-old Japanese man was admitted because of swelling of the left premolar-molar region of the mandible. Radiological examination revealed a multilocular radiolucency with irregular margins. Histological examination of the resected specimen showed infiltrative proliferation of both clear and eosinophilic cells into the adjacent soft tissue without encapsulation, suggesting the malignant potential of the tumor. The tumor cells sporadically formed cystic lesions. In addition, several tumor cell nests showed duct-like characteristics, and many eosinophilic dentin-like structures were attached to the tumor cell nests, suggesting the potential for epithelial-mesenchymal induction. Histochemically, the clear tumor cells possessed cytoplasmic glycogen granules. Both clear and eosinophilic tumor cells showed positive immunoreactivities for cytokeratin 19, epithelial membrane antigen and filaggrin, indicating an odontogenic epithelial origin.

Dentin↗
PubMed2000

Digital ulcers and necroses: novel manifestations of angiocentric lymphoma.

We describe a patient with angiocentric lymphoma whose presenting features were multiple areas of digital ulceration and necrosis, including deep ulcers on both great toes. He lacked the lateral halves of both earlobes because of multiple ulcers. Skin biopsy revealed a patchy and diffuse infiltrate of lymphoid cells with nuclear atypia in the dermis and subcutaneous tissue. Angiocentric and angiodestructive features of the lymphoid cells, a prominent histiocytic infiltrate and some epithelioid cell granulomas were found. The results of immunohistochemical staining showed a T-cell phenotype, and showed positive staining for apoptosis. He died in July 1999. Peripheral vascular disturbances including Raynaud's phenomenon, digital skin ulcers and necroses are novel clinical symptoms in patients with angiocentric lymphoma, which should be added to the differential diagnosis in patients with peripheral vascular disturbances.

Adult↗
PubMed2000

Correlation between diffuse pigmentation and keratinocyte-derived endothelin-1 in systemic sclerosis.

BACKGROUND: The precise mechanism of diffuse pigmentation in systemic sclerosis (SSc) is still unknown. We suspected the participation of endothelin-1 (ET-1), which is produced by keratinocytes, in the hyperpigmentation in SSc. The aims of this study are to demonstrate the hyperproductivity of ET-1 from epidermal cells in SSc by in situ hybridization histochemistry, and to show a correlation between the hyperproductivity of ET-1 in keratinocytes and skin hyperpigmentation. METHODS: In situ hybridization histochemistry was performed on nine SSc specimens (five cases of diffuse scleroderma (dSSc), four cases of acrosclerosis (lSSc)), and compared with four normal control specimens. We counted the grains on 10 x 10 microm(2) of epidermis and microvessels in each histology and examined the degree of skin pigmentation using the skin reflectance factor (Y). RESULTS: In the specimens of the SSc patients, the number of grains on the epidermis was remarkably higher than those of the control specimens (P < 0.01). We found a close correlation between the number of grains and the skin reflectance factor in dSSc patients (P = 0.02). Correlations were not identified between serum ET-1 and skin pigmentation and between serum ET-1 and the frequency of grains on the epidermis. As for grains on microvessels, lSSc patients showed a greater frequency than dSSc patients. CONCLUSIONS: The findings of this study suggest that an increase in the ET-1 productivity of keratinocytes is experienced in SSc patients, especially in dSSc patients. The results suggest a strong correlation between the ET-1 productivity of keratinocytes and skin pigmentation in severe cases of SSc. We conclude from these results that keratinocyte-derived ET-1 plays an important role in the pathogenesis of the hyperpigmentation of the skin in SSc patients.

Adult↗
PubMed2000

The role of endoscopic retrograde cholangiopancreatography in infants with cholestasis.

BACKGROUND/PURPOSE: Endoscopic retrograde cholangiopancreatography (ERCP) was assessed in the diagnosis of cholestatic liver disease in infants. METHODS: ERCP was performed in 50 infants who had prolonged cholestasis. Their ages ranged from 25 to 274 days (mean, 69 days), and their weight ranged from 2.6 to 6.7 kg (mean, 4.7 kg). Incomplete visualization of the biliary tree or visualization of only the pancreatic duct was followed by exploratory laparotomy. In those in whom the biliary tree was visualized completely, the caliber of the bile duct was compared with that of the pancreatic duct. RESULTS: ERCP was completed in 43 patients (success rate, 86%) without complications. In the 7 patients in whom ERCP failed, 6 had biliary atresia (BA) diagnosed by exploratory laparotomy. The other patient had congenital biliary dilatation (CBD). In 29 of the 43 patients, the biliary tree was seen partially or only the pancreatic duct was visualized. These patients had BA diagnosed by laparotomy. Complete visualization of the biliary tree was obtained in 14 patients. Of these, 9 had neonatal hepatitis (NH), 2 had a paucity of intrahepatic bile ducts (PIBLD), and 3 had CBD. In all of the patients with NH, cholestasis improved spontaneously. The 2 patients with PIBLD had biopsy-proven disease. The caliber of the bile duct was larger than that of the pancreatic duct in NH. This relationship was not observed in PIBLD. CONCLUSIONS: ERCP is safe in infants. It is useful in the diagnosis of prolonged cholestasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed2000

Corneal endothelial cell loss in eyes undergoing lensectomy with and without anterior lens capsule removal combined with pars plana vitrectomy and gas tamponade.

PURPOSE: To assess prospectively the comeal endothelial damage associated with pars plana vitrectomy combined with lensectomy and gas tamponade. METHODS: The corneal endothelium was examined with a specular microscope preoperatively and 6 months postoperatively in 42 eyes that underwent pars plana vitrectomy combined with total lensectomy and gas tamponade with SF6 (19 eyes) or C3F8 (23 eyes), and in 12 control eyes that underwent vitrectomy combined with anterior capsule-preserved lensectomy and gas tamponade. RESULTS: The mean +/- SD endothelial cell loss was 17.19+/-7.88% in the SF6 tamponade group, 27.54+/-10.57% in the C3F8 tamponade group, and 3.49+/-2.68% in the control group. Significant differences were found in the mean cell loss among these three groups. The degree of cell loss was significantly related to gas tamponade duration in the eyes with total lensectomy. CONCLUSION: These results suggest that ophthalmic surgeons must try to preserve the lens capsule as much as possible in vitrectomy combined with lensectomy and long-acting gas tamponade in order to prevent corneal endothelial damage.

Adolescent↗
PubMed2000

Decline in the HIV-1 isolation rate in Japan: a 12-year observation.

Since 1988, we have isolated HIV-1 from 614 HIV-1-infected persons (total sample=2,785) in Japan. During the past 12 years, we have found a decline in the HIV-1 isolation rate in Japan, with two identifiable turning points, 1991-1992 and 1996-1997. The two turning points correspond to shifts in anti-HIV-1 therapy. These findings suggest that HIV-1 in Japan is currently biologically well controlled, probably due to anti-HIV-1 therapy. On the other hand, this decline is inconsistent with the recent increase of genetic drug-resistant HIV-1 in Japan. Further studies are needed to clarify mechanisms that might explain the discrepancy.

Adolescent↗
PubMed2000

Suppression of acute viremia by short-term postexposure prophylaxis of simian/human immunodeficiency virus SHIV-RT-infected monkeys with a novel reverse transcriptase inhibitor (GW420867) allows for development of potent antiviral immune responses resulting in efficient containment of infection.

A nonnucleoside reverse transcriptase (RT) inhibitor, GW420867, was tested for postexposure prophylaxis (PEP) in rhesus macaques experimentally infected with 100 50% tissue culture infective doses of a chimeric simian/human immunodeficiency virus (SHIV) containing the RT gene of HIV-1 (SHIV-RT). Animals were either mock treated, or treated for 4 weeks starting at 8 or 24 h postinfection (p.i.) with GW420867. While such therapy led to undetectable plasma viremia in three of six monkeys, a transient plasma viremia was noted in the other three treated animals at 2 to 4 weeks following cessation of therapy. Following this transient viremia all drug-treated animals showed low or undetectable levels of plasma viremia up to the last sample examined at 90 weeks p.i. Despite low and/or undetectable viremia, virus-specific cytotoxic T lymphocyte and viral Env-specific proliferative responses were seen in the peripheral blood mononuclear cells of both mock- and drug-treated animals as early as 3 weeks p.i. Such virus-specific cellular responses, however, were better maintained in the drug-treated animals than the mock-treated animals. In contrast to the virus-specific cellular response, the magnitude and kinetics of virus specific humoral responses appeared to correlate with the detection of viremia. These data support the view that a short-term PEP with GW420867 permits the generation and maintenance of long-lasting virus-specific cell-mediated immune responses while markedly reducing viral loads to undetectable levels for a prolonged period of time (90 weeks) and leads to long-term disease protection. This model provides a unique means to define mechanisms and correlates of disease protection.

Animals↗
PubMed2000

Anti-tetanus toxoid antibody production and protection against lethal doses of tetanus toxin in hu-PBL-SCID mice.

BACKGROUND: In this study, severe combined immunodeficiency (SCID) mice, which permit the survival of lymphoid cells of human origin, were used to study the human anti-tetanus immune response. METHODS: Human peripheral blood lymphocytes (hu-PBL) obtained from 88 healthy donors (aged from 18 to 62) were transplanted into SCID mice, and anti-tetanus toxoid (Ttd) antibody production and protection against lethal doses of tetanus toxin (Ttx) were investigated in the hu-PBL-SCID mice. RESULTS: The transfer of human PBL evoked significant human anti-Ttd IgG antibody production for 37.5% of the donors. After in vivo immunization, the percentage of donors with PBL exhibiting positive anti-TtD IgG production in the mice increased to 54.5%. Mean anti-Ttd IgG levels in the sera were also significantly elevated in response to immunization. The mean IgG titer for the mice injected with PBL from donors under the age of 40 was significantly higher than that of the mice injected with PBL from donors aged 40 or older. Four weeks after the cell transfer, the mice were challenged with Ttx. The induction of protection against Ttx challenge was observed mostly in mice with PBL transferred from donors under the age of 40. In vivo immunization in SCID mice with Ttd increased the number of cases of resistance to Ttx. CONCLUSIONS: These results suggest that hu-PBL-SCID mice might serve as a tool for predicting the protective ability against pathogens in PBL donors and also for evaluating vaccine efficacy.

Adolescent↗
PubMed2000

Lipodystrophia centrifugalis abdominalis infantilis-- immunohistochemical demonstration of an apoptotic process in the degenerating fatty tissue.

We report a case of lipodystrophia centrifugalis abdominalis infantilis (LCAI) showing apoptosis during the lipoatrophic process by immunohistochemical staining. A 3-year-old boy was seen with a 3-month history of a centrifugally spreading depressed eruption without pain and pruritus on his abdomen. He had fever, diarrhea and vomiting for a week at the beginning of his eruption. Physical examination revealed a palm-sized well-demarcated atrophic plaque on his lower abdomen and left inguinal fold. His plaque showed fine erythema peripherally. A skin biopsy specimen showed remarkably decreased subcutaneous fatty tissue. Inflammatory cell infiltration including lymphocytes and histiocytes was noted in the degenerating fatty tissue. In the degenerating subcutaneous fatty tissue, positive staining for HLA-DR, Fas, bcl-2, p53 and transferase-mediated uridine nick end labeling in mononuclear cells were observed. He was diagnosed as having LCAI. The present case showed the possible involvement of apoptosis in the fatty tissue degeneration in LCAI.

Abdomen↗