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Biomedical subjects

N Sato

Publications and source records attributed to N Sato.

At least 577 records · Page 32Linked to original sources
PubMed1998

[Basic evaluation for new antimicrobial susceptibility testing of Mycobacterium tuberculosis by bioluminescence assay of mycobacterial ATP].

It has been reported that the number of living bacteria is correlated to their ATP contents. Based on this, ATP measurement was applied to the susceptibility test for Mycobacterium tuberculosis to antimicrobial agents. ATP was extracted from the bacterial suspension prepared from M. tuberculosis H37Rv grown on 1% Ogawa medium and measured by bioluminescent assay. The highest relative light units (RLU) was obtained when ATP was extracted with the reagent supplied by Kikkoman Inc. (Chiba, Japan) at 100 degrees C for 3 minutes. The amounts of ATP recovered was constant at 100 degrees C for 8 minutes. The ATP contents correlated well with the number of bacteria expressed as CFU. The ATP contents of M. tuberculosis H37Rv inoculated into the Middlebrook 7H9 broth medium containing antituberculous agents were measured at days of 0, 3, 5 and 7. The control culture showed the time-dependent increase in the RLU values, while cultures supplemented with antimicrobial agents reduced their ATP contents concomitant with the concentrations of drugs. The growth of tubercle bacilli was expressed as RLU ratio, the ratio of RLU in the drug-containing cultures to those in drug-free ones. RLU ratio of 0.5 or less was determined as sensitive and the ratio of more than 0.5 as resistant to drugs. The inoculum size of bacteria did not affect the days giving RLU ratio below 0.5 or 0.3. Within 7 days, susceptibilities to drugs could be determined. In conclusion, this test is simple, rapid, sensitive and highly reproducible and useful for the assessment of susceptibility.

Adenosine Triphosphate↗
PubMed1998

[A case of non-photosensitive, self-induced epileptic seizures with pacygyria].

We report an 11-year-old boy with a non-photosensitive epileptic self-induced seizures, pacygyria and familial ataxia. His grandmother and aunts had dysarthria, and his mother had developed progressive ataxia and myoclonus since 40 years old. His older sister had ataxia, mental retardation and epilepsy. As for the boy, motor developmental delay with muscle hypertonicity of left extremities was recognized at the age of 5 months. Mental retardation and ataxia was recognized at the age of 3 years and slight mental regression is recognized at the age of 11 years. No special findings were detected in an examination of his blood and cerebrospinal fluid, including amino acids, lysosomal enzymes activity and genetic analysis for dentatorubralpallidoluysian atrophy. Brain magnetic resonance imaging revealed pachygyria of the right cerebral cortecies. At the age of two, he began to induce seizures with impairment of consciousness in himself by waving his right hand over his face which was directed toward a source of bright light. At the age of seven, he developed spontaneous seizures with impairment of consciousness. An EEG showed frequent spikes in the occipital areas, on the right and left sides occurring either independently or synchronously. Intermittent photic stimulation and pattern stimulation did not induce a paroxysmal discharge in EEG. Ictal EEG suggested that the origin of the seizures was the occipital lobe. Treatment with valporate and zonisamide was effective in reducing the seizures. The findings of our case imply the pathogenesis of self-induced seizures and the relationship between PME and neuronal migration disorders.

Ataxia↗
PubMed1998

Hepatic stellate cell contraction is inhibited by lipo-prostaglandin E1 in vitro.

Prostaglandin E1 (PGE1) has been reported to have, experimentally and clinically, a protective effect against liver damage. This effect may result from the relaxation of hepatic stellate cells, whose contraction induces vasoconstriction of hepatic sinusoids. However, prostaglandins are unstable and a new drug delivery system is necessary to administer a sufficient amount of prostaglandin to achieve a protective effect in the liver. The aim of the study is to investigate the effects of lipo-prostaglandin E1 (lipo-PGE1) which has a novel drug delivery system on the stellate cell contraction induced by endothelin-1 in vitro. Lipo-PGE1 inhibited endothelin-1-induced stellate cell contraction in concentrations of 10, 30 and 50 ng/mL. Therefore, lipo-PGE1 may show a cytoprotective effect in the liver through the relaxation of stellate cells and an increase in the hepatic sinusoidal blood flow.

Alprostadil↗
PubMed1998

Liver regeneration, liver cancers and cyclins.

Accumulating evidence has revealed that malignant cell growth is regulated by complex mechanisms involved in genetic and epigenetic factors. Among human cancers, cancer in the liver (hepatocellular carcinoma (HCC)) is characterized by the evidence that it is usually based on chronic liver diseases such as liver cirrhosis or chronic hepatitis, in which the liver is persistently regenerating following hepatic injury. This raises the possibility that repeated hepatocyte proliferation may cause disorder of genes that are regulating the cell cycle in hepatocytes, thus causing HCC. In this article, recent studies focusing on liver regeneration and cancer are reviewed from the viewpoint of the cell cycle that is regulated by cyclin and the associated proteins.

Carcinoma, Hepatocellular↗
PubMed1998

[Mantle cell lymphoma with marked lymphocytosis at the presentation and with discordant morphology between the lymph node and peripheral blood].

A 72-year-old man was referred to our hospital because of lymphadenopathy, splenomegaly, and leukocytosis. His WBC count was 54,300/microliter, with 89.6% atypical lymphocytes two to three times the diameter of red blood cells, cleaved nuclei, and one or two nucleoli. A lymph node specimen revealed a vaguely nodular pattern, and the diagnosis of mantle cell lymphoma (MCL) was made. The lymphoma cells appeared smaller and more mature than the leukemic cells. The phenotype of the peripheral blood and the lymph node cells was CD5+ CD10- CD19+ CD20+ and the same rearranged JH bands were detected, suggesting that their lymphocytes were of the same origin. In addition, the phenotype of the leukemic cells was CD23+ CD38+ CD43- CD44+ FMC-7+ micro+ chi+. Cytogenetic analysis revealed complex anomalies but not t(11; 14). Cyclin D1 protein was not detected. Because the lymphocyte morphology of the peripheral blood and lymph nodes was discordant, we speculated that variant large cells had proliferated mainly in the peripheral blood. The patient achieved a partial response after 6 courses of CHOP regimen, and was then placed on a COP regimen. He seemed to have MCL, but the following findings were unusual: marked lymphocytosis at initial presentation, discordant morphology, CD5+ CD10- CD23+ CD43- phenotype with neither t(11; 14) or cyclin D1 over-expression.

Aged↗
PubMed1998

In vitro expansion of CD34+/CD41+ cells from human peripheral blood CD34+/CD41- cells: role of cytokines for in vitro proliferation and differentiation of megakaryocytic progenitors.

The aim of this study is to clarify the transitional change of the proliferation and differentiation of human peripheral blood CD34+ cells to megakaryocytic lineage, focusing on its clinical application. We developed a rapid system to purify human peripheral blood CD34+ cells from healthy volunteers, which produced CD34+ cells with a 90% purity. The purified CD34+ cells predominantly consisted of CD41- cells, and the rate of coexpression of CD41 was 0.6% +/- 0.5%. When the purified cells were cultured in liquid phase for 10 days in the presence of recombinant human stem cell factor (rSCF: a ligand for c-kit), interleukin-3 (rIL-3), and thrombopoietin (rTPO: a ligand for Mpl), the number of CD34+/CD41+ cells increased to 19% +/- 7% of total expanded cells on day 4 (4 days of liquid culture) and then gradually decreased to 2.2% +/- 0.6% on day 10. The absolute number of CD34+/CD41+ cells increased and reached a plateau on day 6, and 1.7 +/- 0.6 x 10(5) CD34+/CD41+ cells were produced by 1 x 10(5) CD34+/CD41- day 0 cells. The CD34-/CD41+ cells appeared on day 6, continuously increased in number until day 10, and constituted the main population of expanded cells on day 10, with a value of 38% +/- 18%. On day 10, 19.5 +/- 10.6 x 10(5) of CD34-/CD41+ cells were produced by 1 x 10(5) CD34+/CD41- day 0 cells. The deletion of rTPO from this cytokine combination decreased the number of CD34+/CD41+ and CD34-/CD41+ cells, after days 6 and 8, respectively. Day 0 cells required rIL-3 for promoting colonies containing megakaryocytes, whereas rTPO alone promoted almost no megakaryocytic colonies from day 0 cells. Thus, a combination of IL-3 and SCF expands CD34+/CD41+ cells from CD34+/CD41- cells, and TPO mainly acts to increase CD34-/CD41+ cells. This study suggests that if the expansion of CD34+/CD41+ is performed in vitro, the 6 days' culture of peripheral blood CD34+/CD41- cells with a combination of IL-3 and SCF with TPO provides the most rapid and stable products of CD34+/CD41+ cells for the rapid recovery of platelets in patients with peripheral blood stem cell transplantation.

Adult↗
PubMed1998

Preoperative exocrine pancreatic function predicts risk of leakage of pancreaticojejunostomy.

BACKGROUND: The objective of this study was to clarify the relationship between preoperative exocrine pancreatic function and pancreatic anastomotic leakage after pancreatectomy. METHODS: Fifty-five patients who underwent proximal pancreatectomy with pancreaticojejunostomy were reviewed with regard to preoperative exocrine pancreatic function, size of the main pancreatic duct, postoperative pancreatic juice output, and pancreaticojejunostomy leakage. RESULTS: There were 32 patients with a normal value at the preoperative N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion test (> 70%) and 23 with a low BT-PABA value (< or = 70%). The greatest diameter of the main pancreatic duct in the group with normal BT-PABA results was significantly smaller than that in the group with low BT-PABA results (4.6 +/- 2.7 mm vs 7.1 +/- 4.2 mm; P < .05). The output of pancreatic juice during a 10-day period (from postoperative days 5 through 14) in the group with normal BT-PABA results was significantly higher than that in the group with low BT-PABA results (1738 +/- 898 mL vs 1072 +/- 1174 mL; P < .05). Pancreatic leakage occurred in 8 (25%) of the 32 patients in the group with normal BT-PABA results and in none of the 23 patients in the group with low BT-PABA results (P < .01). CONCLUSIONS: Patients with normal exocrine pancreatic function produce a larger amount of pancreatic juice than those with low exocrine pancreatic function and have a potential risk of anastomotic leakage after pancreatectomy.

4-Aminobenzoic Acid↗
PubMed1997

Interventional treatment for children with severe coronary artery stenosis with calcification after long-term Kawasaki disease.

BACKGROUND: About 4% of children with Kawasaki disease (KD) eventually develop ischemic heart disease, which is often associated with calcified stenosis. We assessed the utility of the percutaneous transluminal coronary rotational ablation (PTCRA) in children with coronary artery stenosis after KD. METHODS AND RESULTS: Four children (three boys and one girl; age, 12 to 13 years) with coronary artery stenosis underwent percutaneous transluminal coronary angioplasty (PTCA) and PTCRA 11.8+/-0.9 years after the onset of KD. Morphology of the coronary artery wall was evaluated by intravascular ultrasound imaging. In one patient, the targeted lesion for intervention was in the left anterior descending artery (90% stenosis); in the other three patients, it was in the middle of the right coronary artery (75% to 90% stenosis). PTCA failed in three patients because of severe stenosis with calcification. However, PTCRA proved effective, with stenosis rates reduced from 90% to 25%. Follow-up coronary angiography performed 4 months after the procedure demonstrated no restenosis, but mild aneurysms occurred in two patients. CONCLUSIONS: This study suggests that PTCRA is useful for revascularizing coronary arteries with severe stenosis and calcification as long-term sequelae of KD. Intravascular ultrasound imaging is useful in assessing the coronary artery wall pathology and in selecting the best treatment intervention.

Adolescent↗
PubMed1997

Molecular cloning of a new aquaporin from rat pancreas and liver.

A new water channel (aquaporin-8, gene symbol AQP8) was isolated from rat pancreas and liver by homology cloning. Ribonuclease protection assay showed intense expression of the gene in pancreas and liver, less intense in colon and salivary gland, and negligible in other organs. The full-length cDNA was obtained by ligation of approximately 1.4-kilobase (kb) cDNA isolated from the rat liver cDNA library to approximately 0.5 kb of the 5'-end fragment obtained by the rapid amplification of cDNA ends method. A major transcript of approximately 1.45 kb was demonstrated in liver and colon by Northern blot analysis. Expression of the cRNA in Xenopus oocytes markedly enhanced osmotic water permeability in a mercury-sensitive manner, indicating a water channel function of this molecule. The open reading frame encoded a 263-amino acid protein with a predicted molecular size of 28 kDa. Hydropathy analysis represented six membrane-spanning domains and five connecting loops containing two sites of NPA motif as preserved in other aquaporins. Unlike other mammalian aquaporins, AQP8 has an unusual structure with a long N terminus and a short C terminus, which are found in plant aquaporin, gamma-tonoplast intrinsic protein. By in situ hybridization, AQP8 mRNA expression was assumed in hepatocytes, acinal cells of pancreas and salivary gland, and absorptive colonic epithelial cells. The physiological role(s) of AQP8 remain to be elucidated.

Amino Acid Sequence↗
PubMed1997

Cloning and expression of the cDNA encoding rat caspase-2.

We have isolated cDNA clones for rat caspase-2 (also called Nedd2/Ich-1), that encodes a protein similar to interleukin-1beta-converting enzyme (ICE) and the product of the nematode Caenorhabditis elegans cell death gene ced-3 both of which play an important role in programmed cell death (PCD). The rat caspase-2 cDNA clones have an open reading frame (ORF) of 452 amino acids (aa). The predicted aa sequence of rat caspase-2 is highly similar to that of mouse Nedd2 (97.3%) and human Ich-1L (91.3%). The aa sequence QACRG containing the active Cys residue, that is necessary for the proteolytic activity of ICE/Ced-3 (caspase) family of proteases, is also conserved in rat caspase-2. Rat caspase-2 also has several Asp residues in the amino and carboxyl cleavage regions similar to other caspase family proteins. We have developed PC12 cells carrying an on/off switching cassette of caspase-2 (named PC-Nd cells), which contains the neo gene flanked by a pair of loxP sites, the Cre-specific recognition sequence of 34 nucleotides (nt), that lies between the promoter and the caspase-2 cDNA. This expression cassette was designed to express the neo gene initially and to turn on the expression of caspase-2 by site-specific recombinase Cre-mediated excisional deletion of the neo gene. After infection with Cre-producing recombinant adenovirus (re-Ad), the expression of caspase-2 was highly induced in PC-Nd cells and presumptive actively processed fragments of caspase-2 were also observed. This gene activation strategy of caspase-2 will be useful for the study of the biological effects of caspase family proteins in PCD.

Amino Acid Sequence↗
PubMed1997

The role of the cytoskeleton in migration and proliferation of a cultured human gastric cancer cell line using a new metastasis model.

Using an in vitro model for investigating the mechanism of migration and proliferation of a cultured human gastric cancer cell line which we established recently, we studied the suppressive effect of inhibitors of the cytoskeleton proteins, actin and myosin, on the migration and proliferation of cancer cells. These inhibitors suppressed the capacity of cancer cells to migrate and proliferate dose-dependently. Thus the integrity of the cytoskeletal system may play an important role in the mechanism of metastasis of gastric cancer cells.

Actins↗
PubMed1997

Manipulation of Th1/Th2 balance in vivo by adoptive transfer of antigen-specific Th1 or Th2 cells.

We have investigated the possibility that the Th1/Th2 balance in vivo may be modulated by adoptive transfer of Th1 or Th2 cells induced in vitro. Thl cells were induced from I-Ad-binding OVA323-339-specific T-cell receptor-transgenic (TCR-Tg) mouse spleen cells by culturing with OVA323-339 peptide and antigen presenting cells (APC) in the presence of IL-2, IL-12 and anti-IL-4 mAb. Th2 cells were induced from TCR-Tg mouse spleen cells by culturing with IL-2, IL-4 and anti-IL-12 mAb in addition to OVA323-339 plus APC. Immunomodulating activities of both Th1 and Th2 cells were determined by their effect on delayed type hypersensitivity (DTH) responses or cytokine production. No significant DTH responses (footpad swelling) were observed in untreated BALB/c mice following a single injection of OVA323-339-pulsed syngeneic spleen cells. However, adoptive transfer of Th1 cells into BALB/c mice induced strong dose dependent DTH responses in response to I-Ad-bound OVA323-339 but not unrelated peptide. In contrast, only slight DTH responses were detected in BALB/c mice transferred with Th2 cells. In parallel with the DTH responses, increased levels of serum IFN-gamma were demonstrated in mice adoptively transferred with Th1, while no significant increase was observed in Th2-transferred mice. In vitro analysis also demonstrated that both spleen cells and popliteal lymph node cells prepared from Th1-transferred mice showed Th1-type cytokine production, while cells obtained from Th2-transferred mice revealed Th2-dominant cytokine production. Such immune deviation induced by antigen-specific Th1 cells was demonstrated up to three months after cell transfer. Therefore, it may be possible to manipulate the Th1/Th2 balance in vivo by adoptive transfer of antigen-specific Th1 or Th2 cells.

Adoptive Transfer↗
PubMed1997

Domain structures and immunogenic regions of the 90-kDa heat-shock protein (HSP90). Probing with a library of anti-HSP90 monoclonal antibodies and limited proteolysis.

Domain structures of the 90-kDa heat-shock protein (HSP90) have been investigated with a library of anti-HSP90 monoclonal antibodies (mAbs) and by limited proteolysis with trypsin and chymotrypsin. Thirty-three mAbs were obtained by immunization with bacterially expressed human HSP90alpha and HSP90beta isoforms. Among them, ten and three mAbs reacted specifically with HSP90alpha and HSP90beta, respectively. Immunoblotting and enzyme-linked immunosorbent analyses revealed that major immunogenic domains were located at two restricted regions of HSP90alpha, i.e. amino acids 227-310 (designated Region I) and 702-716 (Region II), corresponding to a highly charged region and a region near the C terminus, respectively. Taken together with the characteristics of the amino acid sequences, these two immunogenic regions appeared to be exposed at the outer surface of HSP90. We further investigated the domain structures of HSP90 by limited proteolysis in combination with N-terminal sequencing and immunoblotting analyses. Tryptic cleavages of HSP90alpha at low concentrations revealed the existence of major susceptible sites at Arg400-Glu401, Lys615-Ala616, and Arg620-Asp621. Proteolysis at higher trypsin concentrations caused successive cleavages only toward the N-terminal direction from these sites, and Region I was included in the region selectively deleted during this process, thereby further suggesting its surface location. From these results, we propose three domain structures of HSP90 consisting of amino acids 1-400, 401-615, and 621-732. Differences in the protease sensitivity and immunogenicity further suggest that every domain is composed of two subdomains. This is the first study describing the domain structures and the immunogenic regions of HSP90.

Amino Acid Sequence↗
PubMed1997

Prolonged survival of rat skin allograft by treatment with FK506 ointment.

BACKGROUND: We studied the effect of FK506 ointment on rat skin allograft survival. METHODS: Lewis rat (RT1(1)) skin allografts were histologically evaluated on day 7 after transplantation to recipient ACI (RT1a) rats. We set histological gradings for rejection as follows: grade 1, intraepidermal blister formation; grade 2, incomplete epidermal separation from the dermis; and grade 3, complete epidermal separation from the epidermis. According to these histological criteria, the immunosuppressive effect of FK506 ointment was assessed. RESULTS: Our data indicated that all recipient rats without FK506 ointment showed grade 3 rejection on day 7 after transplantation. In contrast, the allografts treated with FK506 ointment showed grade 1 rejection. Furthermore the blood concentration of FK506 was below 0.5 ng/ml, minimizing the systemically adverse effects of FK506. CONCLUSIONS: Thus, the present study suggests that the topical administration of FK506 on the skin allografts may be useful and effective in the suppression of skin allograft rejection.

Animals↗
PubMed1997

Human and Xenopus cDNAs encoding budding yeast Cdc7-related kinases: in vitro phosphorylation of MCM subunits by a putative human homologue of Cdc7.

Saccharomyces cerevisiae Cdc7 kinase is essential for initiation of DNA replication, and Hsk1, a related kinase of Schizosaccharomyces pombe, is also required for DNA replication of fission yeast cells. We report here cDNAs encoding Cdc7-related kinases from human and Xenopus (huCdc7 and xeCdc7, respectively). The cloned cDNA for huCdc7 contains an open reading frame consisting of 574 amino acids with a predicted molecular weight of 63,847 that possesses overall amino acid identity of 32% (54% including similar residues) to Cdc7 and Hsk1. huCDC7 is transcribed in the various tissues examined, but most abundantly in testis. Three transcripts of 4.4, 3.5 and 2.4 kb in length are detected. The 3.5 kb transcript is the most predominant and is expressed in all the tissues examined. A cDNA containing a 91 nucleotide insertion at the N-terminal region of huCDC7 is also detected, suggesting the presence of multiple splicing variants. The huCdc7 protein is expressed at a constant level during the mitotic cell cycle and is localized primarily in nuclei in interphase and distributed diffusibly in cytoplasm in the mitotic phase. The wild-type huCdc7 protein expressed in COS7 cells phosphorylates MCM2 and MCM3 proteins in vitro, suggesting that huCdc7 may regulate processes of DNA replication by modulating MCM functions.

Amino Acid Sequence↗