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Biomedical subjects

H Komatsu

Publications and source records attributed to H Komatsu.

At least 19 recordsLinked to original sources
PubMed1998

Hypomethylation status of CpG sites at the promoter region and overexpression of the human MDR1 gene in acute myeloid leukemias.

Selection of human cells for resistance to vincristine or doxorubicin often induces overexpression of the multidrug resistance 1 gene (MDR1), which encodes the cell surface P-glycoprotein, as a result of gene amplification or transcriptional activation. Moreover, overexpression of the MDR1 gene has been shown to be associated closely with clinical outcome in various hematological malignancies, including acute myeloid leukemia (AML). However, the precise mechanism underlying overexpression of the MDR1 gene during acquisition of drug resistance remains unclear. We recently described an inverse correlation between the methylation status of CpG sites at the promoter region and expression of the MDR1 gene in malignant cell lines. In this study, we expanded this analysis to 42 clinical AML samples. We adapted a quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay for gene expression and a quantitative PCR after digestion by Hpa II for methylation status of the MDR1 gene. We observed a statistically significant inverse correlation between methylation and MDR1 expression in clinical samples. The hypomethylation status of the MDR1 promoter region might be a necessary condition for MDR1 gene overexpression and establishment of P-glycoprotein-mediated multidrug resistance in AML patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Simultaneous determination of bile acids in rat liver tissue by high-performance liquid chromatography.

A method for the simultaneous determination of bile acids in rat liver tissue by high-performance liquid chromatography was developed. Without prior fractionation and alkaline hydrolysis, 30 unconjugated, glycine- and taurine-conjugated bile acids were detected by post-column enzymatic reaction and fluorescence detection. They were separated on a reversed-phase column using a linear gradient solvent system of 10 mM tribasic ammonium phosphate-acetonitrile-methanol (44:12:5, v/v/v) and 20 mM dibasic ammonium phosphate-acetonitrile-methanol (2:1:2, v/v/v). The limits of detection were 1-5 pmol, and calibration curves were linear for concentrations ranging between 10 and 4000 pmol per 10 microl injection. This rapid and reliable method is effective for measuring bile acid levels in liver tissue not only of rats but also of patients with hepatobiliary and other diseases.

Animals↗
PubMed1998

Selective portal blood flow diversion in auxiliary partial orthotopic liver transplantation to induce regeneration of the graft.

Experience with auxiliary partial orthotopic liver transplantation (APOLT) is still very limited and many questions remain to be solved. In this article, we present the case of a 5-year-old girl with ornithine transcarbamylase deficiency who initially did well after APOLT. During a severe rejection episode 16 months after transplantation, she developed encephalopathy and hyperammonemia. Despite a good clinical and histopathological response to antirejection therapy, the graft had become smaller and the native liver had undergone compensatory hypertrophy. After we surgically ligated the right portal branch, the graft recovered and the patient was able to stop her medication 1 month after surgery. We have estimated that the minimum volume of normal liver required to correct the metabolic defect in ornithine transcarbamylase deficiency is 8 cm3/kg. The ligation of the right portal branch was a safe and effective method of inducing a gradual and progressive involution of the hypertrophic native liver and regeneration of the atrophic graft.

Atrophy↗
PubMed1998

Detection of bcr/abl fusion transcripts by semiquantitative multiplex RT-PCR combined with a colormetric assay in Ph positive leukemia.

We studied the feasibility of the clinical application of a new bcr/abl analysis system, C-TRAK t(9;22), consisting of a multiplex RT-PCR and a colormetric assay. With this system, bcr/abl transcripts could be detected in all of 24 cytogenetic Philadelphia chromosome (Ph) positive leukemia patients and in none of eight Ph negative patients. Multiple bcr/abl transcripts could be detected in three of the 24 Ph positive patients, the fusion of bcr exon 1 to abl exon 2 (e1a2 junction) dominated that of bcr exon 13 to abl exon 2 (b2a2 junction) in two cases and that of bcr exon 14 to abl exon 2 (b3a2 junction) and b2a2 dominated e1a2 in one case. This system was sensitive enough to be able to detect even one bcr/abl transcript-producing cell in 50000 bcr/abl negative background cells, thus making it suitable for semiquantitative evaluation. Minimal residual disease (MRD) was monitored in one Ph positive leukemia patient who underwent allogenic bone marrow transplantation (allo-BMT). After allo-BMT, a weak positivity of the bcr/abl transcript continued with no clinical relapse; this result was consistent with that of a conventional nested PCR assay using ethidium bromide staining. Including all the procedures for RNA extraction, it took only about 10 h to detect the bcr/abl transcripts. Our findings indicate that this bcr/abl analysis system provides a quick and sensitive method for screening bcr/abl transcripts and possibly for monitoring MRD in Ph positive leukemia patients.

Acute Disease↗
PubMed1998

Low permeability of liposomal membranes composed of bipolar tetraether lipids from thermoacidophilic archaebacterium Sulfolobus acidocaldarius.

The physical origin of the extremely high thermal stability of tetraether liposomes composed of the polar lipid fraction E (PLFE) from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius has been investigated. The leakage rate of trapped 5, 6-carboxyfluorescein (5(6)CF) and the proton permeability in PLFE liposomes have been measured using fluorescence probe techniques in the temperature range of 25-85 degrees C. The results are compared with those obtained from nonarchaebacterial liposomes. Egg yolk phosphatidylglycerol (eggPG) and PLFE liposomes exhibit similar large negative zeta-potentials (-31 to -34 mV) and low permeability coefficients for 5(6)CF, indicating that membrane surface charge is responsible for the low leakage rate of 5(6)CF in PLFE liposomes. This assertion is confirmed by the observation of an increased leakage rate of 5(6)CF with decreasing membrane surface negative charge via varying the content of egg yolk phosphatidylcholine (eggPC) in eggPC/eggPG binary mixtures. Gel-state dipalmitoylphosphatidylcholine bilayers and PLFE liposomes exhibit similar permeability coefficients for 5(6)CF, suggesting that lipid packing also plays an important role in the low leakage rate of 5(6)CF. PLFE liposomes, especially those approximately 60 nm in diameter, are remarkably thermally stable in regard to proton permeability, which increases by less than 2 x 10(-10) cm/s from 25 to 82 degrees C. The proton permeability comparison of various liposomes reveals that the tight and rigid lipid packing is the major contributor of the extremely low proton permeation in PLFE liposomes; the inositol moiety and the branched methyl groups may also contribute, but to a much lesser extent.

Fluoresceins↗
PubMed1998

Microsatellite instability is rare in the clinical course of myelodysplastic syndrome studied with DNA from fresh and paraffin-embedded tissues.

Microsatellite instability (MSI) has been reported to occur in various types of malignant neoplasms. We performed a polymerase-chain-reaction-based assay for MSI between the initial and the most recently available ("latest") samples from 23 patients with myelodysplastic syndrome (MDS). Of these patients, 15 were informative at more than three microsatellite loci. Seven patients showed an increase in leukemic cells while 8 patients did not during the interval between the two analyses. Only 1 of the patients, who had refractory anemia with excess blasts, which changed to acute myelogenous leukemia, showed microsatellite alteration at the analysis times. Among all 23 patients, two alterations were detected in the 42 informative paired samples that showed an increase in leukemic cells (4.8%), while none was detected in the 59 paired samples without such an increase. In total, therefore only two alterations were detected among 101 informative paired samples (2%). This indicates that MSI is rare in the clinical course of MDS irrespective of disease status, and is consequently not a critical genetic event for disease progression in most MDS patients.

Adult↗
PubMed1998

Early pulmonary resection for localized Mycobacterium avium complex disease.

BACKGROUND: Results of antituberculous chemotherapy for Mycobacterium avium complex disease remain disappointing. Pulmonary resection during an early stage of the disease, therefore, may be beneficial to patients whose disease is localized and who can tolerate a resectional operation. METHODS: Thirty-three patients with localized M avium complex disease underwent 33 pulmonary resections between 1979 and 1996. There were 17 males and 16 females, with a mean age of 50 years (range, 30 to 69 years). Lobectomy was performed in 26 patients, pleuropneumonectomy in 1, segmentectomy in 5, and wedge resection in 1. RESULTS: There was no operative mortality. After pulmonary resection, 31 (94%) patients attained sputum-negative status. Bronchopleural fistula occurred in one patient who underwent a right upper lobectomy. There were two late deaths. A patient with bronchopleural fistula died of respiratory failure two years postoperatively. Another patient died of an unknown cause 12 years postoperatively. Of the 31 patients with negative sputum status postoperatively, only 2 patients (6%) had relapse at 1 and 9 years after operation. CONCLUSIONS: We recommend that patients with this disease be considered for pulmonary resection as early as possible.

Adult↗
PubMed1998

Mycoplasma pneumoniae meningoencephalitis and cerebellitis with antiganglioside antibodies.

A male patient with acute meningoencephalitis and cerebellitis associated with Mycoplasma pneumoniae infection is described. T2-weighted MRI demonstrated a high-intensity lesion involving the deep white matter of the right cerebellar hemisphere, which was not enhanced on injection of gadolinium. Brain perfusion scintigraphy revealed hypoperfusion in the bilateral cerebellar hemisphere. Polymerase chain reaction analysis using M. pneumoniae-specific primers failed to reveal the existence of the M. pneumoniae genome in cerebrospinal fluid. Conversely, serum antibodies to gangliosides (GM1, GM2, and GT1b) were detected, suggesting a mycoplasma-related neurologic disorder mediated by an immunologic mechanism. These findings support the hypothesis that vasculopathy and demyelination caused by an immunologic mechanism play an important role in the pathogeneses of neurologic disorders associated with M. pneumoniae infection.

Autoantibodies↗
PubMed1998

Effect of valine-depleted total parenteral nutrition on fatty liver development in tumor-bearing rats.

Valine-depleted amino acid imbalance, while having a suppressive effect on tumor growth, may induce fatty liver. We administered valine-depleted total parenteral nutrition (TPN) solution to rats subcutaneously transplanted with ascites containing hepatoma AH-109A and examined the time course of the development of fatty liver. An accumulation of fatty vacuoles was observed in hepatocytes on day 4. To prevent the development of fatty liver in tumor-bearing rats, we administered a small amount of valine in addition to the valine-depleted imbalance solution via the central vein. Such treatment, however, resulted in neither the prevention of fatty liver development nor the suppression of tumor growth. To supply valine to the liver, we administered a low concentration of valine via the portal vein simultaneously with central venous administration of valine-depleted TPN solution. As a result, the peripheral blood valine level of these rats was < 0.5 that of the control group, but the valine in the liver was maintained at the same level as that of the control group, and accumulation of triacylglycerols in the liver was slight. However, the suppressive effect on tumor growth was maintained, as the tumor weight was suppressed to almost the same degree as that of rats administered only the valine-depleted solution.

Amino Acids↗
PubMed1998

Arginine vasopressin stimulates phospholipid methylation in cultured rat mesangial cells: possible role for PGE2 production.

Incorporation of [3H-methyl] groups into phospholipids and prostaglandin E2 (PGE2) production in cultured rat mesangial cells were examined in the presence and absence of arginine vasopressin (AVP). In cells stimulated with AVP, a rapid increase in the incorporation of [3H-methyl] group into phospholipids was observed within 1 min after stimulation. The [3H-methyl] group present in the phospholipids began to decline 2.5 min after stimulation. The production of PGE2 increased with AVP treatment, and the decline in methylated phospholipids paralleled the release of PGE2 in AVP-stimulated cells. The inhibition of phospholipid methylation by treatment with adenosyl-S-isobutyl mercaptan (SIBA) resulted in a marked decrease in AVP-stimulated PGE2 production. In order to determine the identity of the methylated phospholipids, [3H-methyl] incorporation into phosphatidylethanolamine derivatives was examined. In AVP-stimulated cells, an increase of [3H-methyl] labeled phosphatidylcholine and lysophosphatidylcholine was observed after stimulation with AVP, followed by an apparent increase of [3H-methyl] labeled lysophosphatidylcholine. These findings indicate that AVP stimulates phospholipid methylation in cultured rat mesangial cells and phosphatidylcholine, synthesized by a transmethylation pathway, may be a source for PGE2 production.

Animals↗
PubMed1998

Mechanisms of central color vision.

In monkey cerebral cortex, color information is processed along the ventral visual pathway. This pathway starts in the primary visual cortex and ends in area TE of the inferior temporal cortex. Recent studies indicate that the transformation of cone signals occurs early in the pathway to form neurons selective to a narrow range of hues. In addition, it has become apparent that area TE plays a vital role in color discrimination.

Animals↗
PubMed1998

Transient appearance of CD3+CD8+ T lymphocytes with monoclonal gene rearrangement of T-cell receptor beta locus.

A benign, transient proliferation of atypical lymphocytes and a monoclonal rearrangement of the T-cell receptor beta (TRB) locus was found in a 60-year-old woman who presented with low-grade fever, anorexia and fatigue. A marked and transient atypical lymphocytosis (white blood cell count 90.5 x 10(9)/l) with CD8 surface antigen improved without specific treatment. Although tests for IgM antibodies to hepatitis A, varicella zoster, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) were all negative, a monoclonal gene rearrangement of TRB locus was observed in the DNA of the proliferated atypical lymphocytes by Southern blotting. The clonal rearrangement and the atypical lymphocytes disappeared after 14 d, and the patient has remained well for 7 years. These results suggest that monoclonal proliferation of CD8 lymphocytes can occur based on a non-neoplastic aetiology.

Blotting, Southern↗
PubMed1998

A normative, community-based study of Mini-Mental State in elderly adults: the effect of age and educational level.

We investigated community-based data of the Mini-Mental State Examination (MMSE) scores of elderly residents along with the effects of age and educational level. MMSE was planned for all residents over 65 years of age in a town in northern Japan. The number of elders who took the MMSE was 2,266 (90%). The score significantly declined with age and lower educational level, although no effect of sex was apparent. For the MMSE subitems, all the values except for that of naming showed effects of both age and educational level. Those screened by MMSE who fell in the range of cognitive impairment (< 24) accounted for 21.8% and those with severe cognitive impairment (< 18) constituted 6.0%. Despite the differences in language and culture, the mean scores are remarkably similar between Japan and other countries. This is the first normative, community-based study of MMSE among elderly adults in Japan.

Aged↗
PubMed1998

Comparison of patient-controlled epidural analgesia with and without background infusion after gastrectomy.

UNLABELLED: To assess the analgesic efficacy and side effects of concurrent infusion in patient-controlled epidural analgesia (PCEA) after upper abdominal surgery, 40 patients undergoing elective gastrectomy under general anesthesia were allocated to two groups in this randomized, double-blind study: one received a 2.5-mL incremental bolus in a solution of 0.2% bupivacaine and 10 microg/mL fentanyl, and the other received the same bolus dose plus a 2.5-mL/h infusion of the same solution. The number of demands was smaller (P < 0.001) in the PCEA plus infusion group than in the PCEA alone group during the 48-h postoperative period. The average hourly fentanyl and bupivacaine doses were larger (P < 0.0001) in the PCEA plus infusion group than in the PCEA alone group. Visual analog scale pain scores on coughing in the PCEA plus infusion group were lower than in the PCEA alone group (P < 0.05). There was a greater incidence of pruritus in the PCEA plus infusion group (P < 0.05), but no serious side effects were observed in either group. In conclusion, a background infusion in PCEA with a mixture of fentanyl and bupivacaine decreases the incidence of postoperative pain and reduces the degree of pain associated with coughing without serious side effects after gastrectomy. IMPLICATIONS: A background infusion in patient-controlled epidural analgesia with a mixture of fentanyl and bupivacaine decreased the incidence of postoperative pain and reduced the degree of the pain associated with coughing without serious side effects in this randomized, double-blind study after gastrectomy.

Aged↗
PubMed1998

Repetitive post-training exposure to enflurane modifies spatial memory in mice.

BACKGROUND: Previously the authors found that a single post-training exposure to enflurane or isoflurane, but not halothane, enhanced memory storage in an active avoidance task, which is a behavior with underlying mechanisms that are poorly understood and still debated. In contrast, spatial tasks are known to depend on hippocampal functions. This study investigated the effects of repetitive post-training exposure to enflurane on spatial memory in mice. METHODS: Using an eight-arm radial maze, 80 mice were trained to eat a pellet placed on the end of each of the eight arms. Training occurred on four consecutive days with one trial per day. The number of errors in the first eight choices was recorded to determine performances for each day of training. Immediately after each training session, mice in the enflurane group received 1 h exposure to 0.5%, 1%, or 2% enflurane in air through a calibrated vaporizer. The performance ratios (the ratio of errors on each day compared with the first day of the 4 days) in the control and the enflurane groups were compared. RESULTS: The performance ratios (which equals the mean of the error in the fourth day/the error in the first day) in the control, and 0.5%, 1%, and 2% enflurane groups were 0.66, 0.65, and 0.32 (P < 0.01, vs. control), and 0.46 (P < 0.05, vs. control), respectively. CONCLUSIONS: Repetitive post-training exposure to 1% and 2% enflurane significantly enhanced spatial memory in the eight-arm radial maze task. Enflurane enhances consolidation of spatial memory, possibly by affecting hippocampal activity.

Anesthetics, Inhalation↗
PubMed1998

Treatment of subdural effusion with hydrocephalus after ruptured intracranial aneurysm clipping.

OBJECTIVE: This study was conducted to determine whether a ventriculoperitoneal shunt alone was effective in treating subdural effusion with hydrocephalus. METHODS: Using only a ventriculoperitoneal shunt, we successfully treated eight patients who had subdural effusion with hydrocephalus after ruptured intracranial aneurysmal clipping, despite ventricular deformity and midline shift. RESULTS: For all of the patients, both the subdural effusion and ventriculomegaly subsided and clinical symptoms lessened after surgery. CONCLUSION: Ventriculoperitoneal shunting alone is an effective and satisfactory procedure; no subdural peritoneal shunt is needed for patients with subdural effusion accompanied by hydrocephalus. To-and-fro communication between the subdural effusion and ventricles is considered to be present in these patients. When selecting the treatment for subdural effusion, it is important to consider whether hydrocephalus (disturbance of cerebrospinal fluid circulation) is present.

Adult↗
PubMed1998

Values for urinary beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase in normal healthy infants.

BACKGROUND: Measuring urinary beta 2 microglobin (B2M) and N-acetyl-beta-D-glucosaminidase (NAG) excretion is widely used as a valuable clinical tool in assessing renal tubular lesions. However, few data are available on normal values for urinary excretion of B2M and NAG in infancy. METHODS: Urinary B2M and NAG were measured in healthy infants. The logarithmic values of urinary B2M, NAG, B2M/creatinine ratio and NAG/creatinine ratio were distributed almost normally and reference ranges were calculated from the logarithms of the observed values. RESULTS: The levels of urinary B2M and B2M/creatinine ratio were highest in the 1-month-old group, followed by a decrease during the first 3 months. Urinary B2M excretions in the 3-month-old group showed rather lower levels than those of the 12-month-old and 36-month-old groups. Although urinary NAG excretions were almost constant throughout all groups, urinary NAG/creatinine ratio decreased gradually until 3 years of age. CONCLUSIONS: We suggest that these reference ranges are of importance in evaluating tubular damage due to a variety of renal diseases in infancy.

Acetylglucosaminidase↗