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T Ogawa

Publications and source records attributed to T Ogawa.

At least 109 records · Page 6Linked to original sources
PubMed2001

Osteoclast differentiation factor modulates cell cycle machinery and causes a delay in s phase progression in RAW264 cells.

Osteoclast differentiation factor (ODF) induces differentiation of mouse RAW264 cells to mature osteoclasts. To understand the mechanism controlling a coupling between withdrawal from the cell cycle and differentiation, we examined cell cycle progression and expression profiles of cell cycle regulatory genes at the initial phase in committed cells. ODF rapidly converted the hyperphosphorylated form of the retinoblastoma protein (pRb) into the hypophosphorylated form. The p21 protein was induced by ODF treatment in the same time course with that of dephosphorylation of pRb, followed by a sharp decline. After this period, a delayed entry of the S phase started accompanying the induction of CycD3 and cdk6 in differentiating cells. Hydroxyurea treatment indicated that the S phase entry was a prerequisite for osteoclast formation. Thus, ODF induces pleiotropic effects on cell cycle regulatory genes in RAW264 cells during the initial phase of the differentiation process to osteoclasts.

Animals↗
PubMed2001

Nondestructive quantification of neutral lipids by thin-layer chromatography and laser-fluorescent scanning: suitable methods for "lipidome" analysis.

A simple method for separation and quantification of neutral lipids was developed using thin-layer chromatography (TLC) and high-performance fluorescent scanning. Neutral lipid classes were separated using the double-developing TLC method and detected by rhodamine 6G and a laser-excited fluorescent scanner. The amount of lipids applied correlated with scanned intensity volume in a dose-dependent manner. The mass of each neutral lipid band was determined by comparing band intensities of unknown samples to dilution curves of authentic standards. After scanning the dye-sprayed TLC, acyl chain species of triglyceride (TG) extracted from TLC could be determined by gas chromatography. Using this method, we quantified the amounts of TG in mouse liver and found that the measured total mass of TG correlated with that obtained by enzymatic methods. Our method should provide the basic technique for "lipidome" analysis, designed to determine and compare total lipid classes and mass present in biological samples.

Animals↗
PubMed2001

3-hydroxy-3-methylglutaryl coenzyme A reductase is sterol-dependently cleaved by cathepsin L-type cysteine protease in the isolated endoplasmic reticulum.

We have recently shown that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, an endoplasmic reticulum (ER) membrane protein, is degraded in ER membranes prepared from sterol pretreated cells and that such degradation is catalyzed by a cysteine protease within the reductase membrane domain. The use of various protease inhibitors suggested that degradation of HMG-CoA reductase in vitro is catalyzed by a cathepsin L-type cysteine protease. Purified ER contains E-64-sensitive cathepsin L activity whose inhibitor sensitivity was well matched to that of HMG-CoA reductase degradation in vitro. CLIK-148 (cathepsin L inhibitor) inhibited degradation of HMG-CoA reductase in vitro. Purified cathepsin L also efficiently cleaved HMG-CoA reductase in isolated ER preparations. To determine whether a cathepsin L-type cysteine protease is involved in sterol-regulated degradation of HMG-CoA reductase in vivo, we examined the effect of E-64d, a membrane-permeable cysteine protease inhibitor, in living cells. While lactacystin, a proteasome-specific inhibitor, inhibited sterol-dependent degradation of HMG-CoA reductase, E-64d failed to do so. In contrast, degradation of HMG-CoA reductase in sonicated cells was inhibited by E-64d, CLIK-148, and leupeptin but not by lactacystin. Our results indicate that HMG-CoA reductase is degraded by the proteasome under normal conditions in living cells and that it is cleaved by cathepsin L leaked from lysosomes during preparation of the ER, thus clarifying the apparently paradoxical in vivo and in vitro results. Cathepsin L-dependent proteolysis was observed to occur preferentially in sterol-pretreated cells, suggesting that sterol treatment results in conformational changes in HMG-CoA reductase that make it more susceptible to such cleavage.

Acetylcysteine↗
PubMed2001

Characterization of whole blood aggregation with a new type of aggregometer by a screen filtration pressure method.

A new type of platelet aggregometer of whole blood, based on the screen filtration pressure method, has been developed and characterized. It measures resistance of flow of whole blood samples through a screen of microsieve with 30-microm(2) openings and provides pressure rate as an index of platelet aggregation. On optical microscopic observation, platelet aggregates, but not fibrin fibers, were found to be trapped on microsieves, and the pressure rate and protein amounts on microsieves are correlated. The aggregometer showed good reproducibility for investigations performed on different days. The time course of pressure rates indicated a bell curve change, where the pressure rate was very low immediately after blood collection and gradually increased up to 60 min thereafter. Use of the aggregometer was able to confirm that orally administered aspirin inhibits ADP- and collagen-induced whole blood aggregation as well as platelet aggregation. The results suggest that this platelet aggregometer might be useful in research and clinical diagnosis of thrombotic diseases.

Adenosine Diphosphate↗
PubMed2001

Nicotine exposure during pregnancy is a factor which influences serotonin transporter density in the rat brain.

We examined the effects of nicotine exposure during pregnancy on serotonin transporter (SERT) expression in the brain. Nicotine (6 mg/kg/day) was administered to pregnant rats via subcutaneous injections or infusion pumps. Irrespective of the route of administration, nicotine increased SERT density in the forebrain on postnatal day 22, but not in the other brain regions. Our results suggest that nicotine use by pregnant women might be an environmental factor influencing SERT expression in their children.

Animals↗
PubMed2001

Evaluation of hydration states of protein in freeze-dried amorphous sugar matrix.

A model to analyze the hydration state of protein in freeze-dried amorphous sugar matrix was proposed, based on the assumptions that there is a limit to the amount of protein that a given amount of amorphous sugar could embed and that the freeze-dried sugar-protein mixture is composed of the four components, i.e., sugars with and without hydrogen bonding to proteins and proteins with and without hydrogen bonding to sugar. Bovine serum albumin and three kinds of disaccharides, i.e., sucrose, maltose, and trehalose, were used as samples. Using the analytical equations derived from the model and experimental sugar content dependencies of the water sorption at various relative humidities, the amount of hydration water for bovine serum albumin, and the minimum amount of sugar to embed the protein were determined. On the basis of these results, the degree of interaction between the three sugars and protein was discussed, with respect to their stabilizing effect on the protein.

Carbohydrates↗
PubMed2001

CpG island of rat sphingosine kinase-1 gene: tissue-dependent DNA methylation status and multiple alternative first exons.

It is generally recognized that CpG islands are not methylated in normal tissues. SPHK1 is a key enzyme catalyzing the production of sphingosine 1-phosphate, a novel signaling molecule for the proliferation and differentiation of various cells, including neural cells. Sequencing of genomic DNA and cDNA reveals that rat Sphk1a consists of six exons encoding 383 amino acids. Furthermore, we identified six alternative first exons for mRNA subtypes (Sphk1a, -b, -c, -d, -e, and -f) within a 3.7-kb CpG island. The CpG island contains a tissue-dependent, differentially methylated region (T-DMR; approximately 200 bp), which is located - 800 bp upstream of the first exon of Sphk1a. T-DMR is hypomethylated in the adult brain where Sphk1a is expressed, whereas it is hypermethylated in the adult heart where the gene is not expressed. In fetal tissues, hypomethylation of T-DMR is not associated with expression of Sphk1a, which suggests that differential availability of transcription factors is also likely to be involved in the mechanism of its expression. Here, we identify rat Sphk1, using multiple alternative first exons for the subtypes, and demonstrate that there is a CpG island bearing T-DMR.

Alternative Splicing↗
PubMed2001

Blood transfusion causes deterioration in liver regeneration after partial hepatectomy in rats.

BACKGROUND: This study investigated the effects of blood transfusion on liver regeneration and function after hepatectomy in rats. METHODS: Inbred male Sprague-Dawley rats underwent a sham operation or a 70% hepatectomy (PHx) and were randomly divided into seven groups according to transfusion type: groups I and II underwent a sham operation and received saline (I) or whole blood (II). Groups III to VII underwent PHx with saline (III), whole blood (IV), irradiated/leukocyte-depleted whole blood (V), plasma (VI), or autologous blood (VII). The liver regeneration rate, proliferating cell nuclear antigen (PCNA) labeling index, serum aspartate aminotransferase, alanine aminotransferase, purine nucleoside phosphorylase (PNP) activity, hepatocyte growth factor (HGF), and activated transforming growth factor beta1 (TGF-beta(1)) were measured 6 and 24 h and 5 days after PHx. RESULTS: The liver regeneration rate and PCNA labeling index were lower in groups IV and V than in the other groups. Serum liver enzymes 6 h after PHx were worst in groups IV and V. PNP activity increased most in group IV, 6 and 24 h after PHx. The HGF values 6 h after PHx in all the transfused groups were lower than in group III. The activated TGF-beta(1) level 6 h after surgery was highest in group IV. CONCLUSION: Whole blood or irradiated/leukocyte-depleted whole blood impaired liver regeneration after PHx, probably through the production of activated TGF-beta(1) and HGF outside the liver, and plasma or autologous blood reduced the deleterious effects.

Animals↗
PubMed2001

Brain perfusion SPECT study with 99mTc-bicisate: clinical pitfalls and improved diagnostic accuracy with a combination of linearization and scatter-attenuation correction.

To evaluate the usefulness of a combination of linearization and scatter-attenuation correction on 99mTc-bicisate (ECD)-single photon emission tomographic (SPECT) images, both cerebral blood flow (CBF)-positron emission tomographic (PET) images and ECD-SPECT images from fifteen patients with chronic cerebral infarction were acquired. We measured radioactivity counts in regions of interest (ROIs) on all sets of both images and obtained a 2D scattered graph between ECD-SPECT and CBF-PET data. To evaluate diagnostic accuracy, the sensitivity, specificity and accuracy of ECD-SPECT images were calculated by means of discriminant analysis. The same analysis was also performed on the ECD-SPECT images corrected by a combination of linearization and scatter-attenuation correction. An overall nonlinear relationship was observed between ECD-SPECT and CBF-PET. The sensitivity, specificity, and accuracy of ECD-SPECT images were 69.6%, 91.4% and 73.0%, and those of ECD images corrected by the combination of linearization and scatter-attenuation correction were 79.5%, 95.7% and 82.0% respectively. The clinically diagnostic accuracy of ECD-SPECT images corrected by the combined method apparently increased. So that the linearization with the scatter-attenuation method is useful for improving the diagnostic accuracy of ECD-SPECT images.

Aged↗
PubMed2001

FK506 is superior to methotrexate in therapeutic effects on advanced stage of rat adjuvant-induced arthritis.

OBJECTIVE AND DESIGN: The anti-arthritic properties of FK506 were compared with methotrexate (MTX) in established adjuvant-induced arthritis (AIA) in rats. MATERIAL: Female Lewis rats. TREATMENT: Arthritic rats were orally administered with FK506 (1-5.6 mg/kg) and MTX (0.1-1 mg/kg) from days 15-24. METHODS: Arthritis was induced by injection of Mycobacterium tuberculosis into the right hind footpad on day 0. Efficacy was determined on the basis of paw inflammation measured by paw volume and histological change, hyperalgesia and grip strength. Grip strength measurement was employed as an indication of function of paws in arthritic rats. Peripheral white blood cell (WBC) counts and thymus weights were measured, mainly as indicators of toxic side effects. RESULTS: FK506 suppressed paw inflammation and hyperalgesia without toxic effects on WBC and thymus in established AIA. MTX slightly suppressed paw inflammation and hyperalgesia at the highest dose (1 mg/kg). Toxic effects were observed at lower doses than the effective treatment dose with MTX. Grip strength was found to decrease during development of AIA. FK506, but not MTX, treated rats recovered grip strength loss. CONCLUSIONS: The results show that FK506 is more effective and less toxic than MTX in treating established AIA in rats.

Animals↗
PubMed2001

Spermatogonial transplantation: the principle and possible applications.

Spermatogenesis is the process of male germ cell proliferation and differentiation that begins at puberty and lasts throughout life. Spermatogonia, especially stem spermatogonia, are the cells essential for the continued maintenance of spermatogenesis. Although many studies of spermatogonia have been performed with morphological methods, the very nature of spermatogonia still remains unknown. The technique of spermatogonial transplantation, developed in 1994, made it possible to study functional aspect of spermatogonial stem cells. Many new developments, such as cryopreservation, xenotransplantation, purification, and culturing of spermatogonial stem cells, have been achieved and are still under investigation. The techniques could be used not only for basic research but also for medicine and other disciplines.

Animals↗
PubMed2001

High-intensity facial nerve lesions on T2-weighted images in chronic persistent facial nerve palsy.

Our aim was to estimate the value of MRI in detecting irreversibly paralysed facial nerves. We examined 95 consecutive patients with a facial nerve palsy (14 with a persistent palsy, and 81 with good recovery), using a 1.0 T unit, with T2-weighted and contrast-enhanced T1-weighted images. The geniculate ganglion and tympanic segment had gave high signal on T2-weighted images in the chronic stage of persistent palsy, but not in acute palsy. The enhancement pattern of the facial nerve in the chronic persistent facial nerve palsy is similar to that in the acute palsy with good recovery. These findings suggest that T2-weighted MRI can be used to show severely damaged facial nerves.

Adolescent↗
PubMed2001

Developmental changes in cyclooxygenase mRNA expression in the kidney of rats.

Prostaglandins, synthesized by cyclooxygenase (COX), regulate renal hemodynamics and also epithelial water and solute transport. To determine whether COX mRNA expression changes with age, we studied expression in renal medulla and in cortex in developing rats at various ages. We also examined age-related changes in COX mRNA expression induced by lipopolysaccharide (LPS). COX mRNA was quantitatively analyzed in a real-time polymerase chain reaction (PCR) with dual-labeled fluorogenic probes. COX-1 mRNA expression did not change with age in cortex or medulla. COX-2 mRNA expression was highest in 1-week-old rats and lowest in 4- and 8-week-old rats. Lipopolysaccharide treatment did not alter COX-1 mRNA expression in infantile or adult rats. In adults, LPS at 1, 5, and 10 mg/kg induced COX-2 mRNA expression in renal medulla; the higher doses, 5 and 10 mg/kg, induced COX-2 expression in cortex. In infantile rats, COX-2 mRNA, already high in the unmanipulated state, was further increased by only 1 mg/kg LPS in both renal cortex and medulla. Age-related changes in the expression of COX-2 mRNA might be responsible for changing physiologic characteristics of renal function during postnatal development in rats, and may be important in renal cortical development.

Aging↗
PubMed2001

Comparison of laparoscopic versus open cholecystectomy in patients with cardiac valve replacement.

To evaluate the benefits and safety of laparoscopic cholecystectomy (LC) in patients with cardiac valve replacement (which frequently leads to cholelithiasis), 12 patients with cholelithiasis associated with cardiac valve replacement were studied. The patients were divided into two groups, of 6 patients each, according to the type of operation performed, open cholecystectomy (OC) or LC. The postoperative course was monitored with respect to laboratory data on postoperative days (POD) 1, 3, and 7. The mean duration of operation, blood loss, days to food resumption, length of hospital stay, and morbidity were compared between the two groups. Significant differences (P < 0.05) were found between the OC and LC groups in white blood cell counts on POD 1 (12 980 +/- 3040/mm3 vs 8300 +/- 1590/mm3), days to food resumption (2.7 +/- 0.4 days vs 1.0 +/- 0.7 days), and length of postoperative stay (15.8 +/- 1.0 days vs 10.8 +/- 1.6 days). There were no complications in the LC group, but 1 patient in the OC group had heart failure postoperatively. Our findings indicate the efficacy and safety of LC in patients with cardiac valve replacement.

Adult↗
PubMed2001

Mucin-producing tumor of the pancreas associated with pyothorax: report of a case.

We report herein the case of a 76-year-old man for whom an invasive mucin-producing tumor of the pancreas (MPTP) was successfully treated by surgery. A cystic lesion of the pancreas had been found by computed tomography (CT) 9 years earlier, 2 years following which suction drainage for left pyothorax had been carried out. A pancreatic cyst fistula to the thorax had subsequently been found during decortication for recurrent pyothorax 2 years later. Methicillin-resistant Staphylococcus aureus was detected in the pleural discharge after the thoracotomy, and thoracic fenestration was performed. A CT scan done 4 years later showed enlargement of the pancreatic cysts and a cystography revealed communication to the duodenum via the main pancreatic duct. Endoscopic retrograde cholangiopancreatography (ERCP) showed dilatation of the main pancreatic duct. The pancreatic cyst fistulated to the stomach and to the fenestrated thorax. Since MPTP was suspected from this clinical course, a distal pancreatectomy, partial gastrectomy, and omentopexy to the thorax were performed. The pathological diagnosis was intraductal papillary-mucinous tumor of the pancreas with a megacyst. While MPTP is recognized as a low-grade malignancy, some cases of invasive disease have been reported. To the best of our knowledge, this is the first case of MPTP associated with pyothorax due to fistula formation.

Aged↗
PubMed2001

Penetration of the duodenum by an ingested needle with migration to the pancreas: report of a case.

A case of a penetration of the duodenum by a needle with migration to the pancreas in a 50-year-old man is reported herein. The patient was referred to us with a chief complaint of diarrhea. An abdominal plain roentgenogram showed a needle in the upper abdominal area. An abdominal computed tomography scan and contrast X-ray revealed the foreign body to be located outside of the duodenum and in the head of the pancreas. An emergency operation was therefore performed on the first day and the needle in the head of the pancreas was thus extirpated safely. A perforation of the gastrointestinal tract by an ingested foreign body is difficult to accurately and quickly diagnose when no peritonitis or abscess formation is observed. Therefore, the use of contrast X-ray is considered to be useful in the diagnosis of such a perforation.

Contrast Media↗
PubMed2001

Random amplified polymorphic DNA analysis applied to acute otitis media caused by penicillin non-susceptible Streptococcus pneumoniae.

The spread of penicillin non-susceptible Streptococcus pneumoniae (PNSSP) is an emerging problem for the treatment of acute otitis media (AOM). Attendance of children at day care centers, as well as the spread of PNSSP, is a risk factor for AOM. The status of the spread of PNSSP during the acute infection phase of AOM has not been evaluated. We examined the clonality of samples from seven children in a day care center who simultaneously developed AOM caused by PNSSP. The seven isolates from the children, and six control samples were grouped by serotyping, by determining resistance to antimicrobial agents, and by genotyping, carried out by sequencer-based random amplified polymorphic DNA (RAPD), and validated by bootstrap analysis. There was no evidence to indicate the direct dissemination of PNSSP among these patients in the day care center, although the simultaneous occurrence of PNSSP AOM had initially suggested a clonal outbreak. The possible presence of a common ancestral strain suggested the importance of surveillance during the carrier state. The result of RAPD genotyping was highly reproducible, as validated by the high bootstrap score. The use of an automated sequencer, in combination with a careful choice of primers, and commercially established kits, played a significant role in the reproducibility of the studies.

Child↗