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Biomedical subjects

T Kubota

Publications and source records attributed to T Kubota.

At least 271 records · Page 15Linked to original sources
PubMed1999

Compensatory response of colon tissue to dextran sulfate sodium-induced colitis.

Depletion of goblet cells (the main mucin-producing cells in the colon) is one of the most reliable histological characteristics of ulcerative colitis, whereas a major symptom of this disease is bloody diarrhea containing a large amount of mucus. The discrepancy between these phenomena was investigated in a time-course study in rats with experimental colitis induced by treatment with oral dextran sulfate sodium (DSS) for 1, 3, or 5 days. Biochemical analysis showed a reduction in mucin content in the distal side of the colon that was proportional to the duration of DSS administration. In the proximal side of the colon, however, there was a significant increase in mucin content already on the first day of treatment with DSS. This increase in colonic mucin content continued for the 5 days of treatment. In the distal side, both sulfomucin and sialomucin decreased proportionally to the duration of DSS administration. In the proximal side, there was an increase in high iron diamine-Alcian blue-positive mucins, and confirming the proliferation of goblet cells. The proliferated glands were predominantly sialylated. Goblet cell depletion and an increase in mucin production occurred in different parts of the colon. This phenomenon may be a type of compensatory function of colon tissue in response to the localized decrease of mucin production in certain portions of the colon.

Animals↗
PubMed1999

Alterations of calcium/calmodulin-dependent protein kinase II activity in ischaemia-induced neuronal death and neuronal protection against ischaemia in the gerbil hippocampus.

To clarify the relation between neuronal protection against ischaemia and calcium/calmodulin-dependent protein kinase II (CaM kinase II) activity, we investigated temporal alterations of the kinase activity in the hippocampus after transient forebrain ischaemia under neuroprotective conditions, employing the gerbil bilateral carotid artery occlusion model. The hippocampal CA1 neuronal density at 2 hours after 5 minutes of forebrain ischaemia was 214.7 +/- 25.8/mm (mean +/- S.D.), and did not differ from the control significantly; however, it decreased to 11.7 +/- 4.2/mm at 7 days after the ischaemia. The neuronal density at 7 days after the ischaemia was 185.1 +/- 18.5 under the hypothermic conditions, 128.7 +/- 19.6 with the brief ischaemic pretreatment, 65.0 +/- 13.4 with administration of MK-801, and 20.5 +/- 4.2 with the repetitive hyperthermic pretreatment, respectively. The Ca2+/calmodulin-dependent activity of CaM kinase II in the hippocampal cytosolic fraction was decreased to 47.5% of the control value at 2 hours after the ischaemia, when CA1 neuronal death was not observed. In contrast, the activity was 98.8% of the control under the hypothermic conditions, 91.4% with the brief ischaemic pretreatment, 71.2% with administration of MK-801, and 47.9% with the repetitive hyperthermic pretreatment, respectively. These results indicated that the preservation of the Ca2+/calmodulin-dependent activity of cytosolic CaM kinase II after ischaemia parallelled the neuroprotective effect in the gerbil hippocampus. Thus, it is suggested that the preservation of the activity may be involved in the mechanism of neuronal protection against ischaemia.

Animals↗
PubMed1999

Clinical applications of two-color telomeric fluorescence in situ hybridization for prenatal diagnosis: identification of chromosomal translocation in five families with recurrent miscarriages or a child with multiple congenital anomalies.

Two-color fluorescence in situ hybridization (FISH) analysis using human chromosome arm-specific telomeric probes (telomeric probes) was used successfully to detect each derivative chromosome of a translocation carrier in five couples who requested a prenatal diagnosis in future pregnancies. Most of the human chromosome terminal bands are G-band-negative, and even FISH analysis using whole-chromosome painting (wcp) probes are often of insufficient complexity to detect subtle chromosomal changes. A complete set of human telomeric probes was developed to improve the sensitivity of diagnosis of microdeletions or other cryptic rearrangements in telomeric regions. Two-color telomeric FISH was the only possible method for precise prenatal diagnosis of one of the couples, because the carrier's chromosomal aberration was too subtle to be detected by wcp FISH or conventional methods. We have demonstrated that two-color telomeric FISH has the potential to be a powerful new tool in the detection of cryptic chromosomal rearrangements involving telomeric regions in prenatal diagnosis precisely and in time.

Abnormalities, Multiple↗
PubMed1999

Production and characterization of monoclonal antibodies that recognize bovine Kit receptor.

Kit receptor is a transmembrane tyrosine kinase that is the receptor for stem cell factor (SCF). The extracellular domain of bovine Kit receptor (boKit) was produced by a baculovirus expression system. Six monoclonal antibody (MAb) clones designated as bK-1 to bK-6 were obtained upon immunization of mice with the recombinant protein. Immunoprecipitation and flow cytometric analysis indicated that all of the MAbs specifically bound to boKit expressed in COS-7 cells transfected with boKit cDNA. Four of the six MAbs neutralized the biological activity of recombinant bovine SCF, whereas the other two did not. The boKit-positive and boKit-negative cell fractions were sorted from cryopreserved bovine bone marrow cells by the use of MAb bK-1. Colony formation assays indicated that the cells which were able to grow in response to bovine SCF were enriched in the boKit-positive fraction. These MAbs would be valuable in studying possible boKit-positive cell species such as bovine hematopoietic cells, and in defining the biological role of Kit receptor in cattle.

Animals↗
PubMed1999

The effects of nitrous oxide and ketamine on the bispectral index and 95% spectral edge frequency during propofol-fentanyl anaesthesia.

In this study, we have sought to establish whether N2O and ketamine alter the bispectral index during propofol-fentanyl anaesthesia. Fourteen surgical patients were randomly assigned to one of two groups: the N2O group (n = 7) and the ketamine group (n = 7). In both groups, anaesthesia was induced with propofol 1.5-2 mg kg-1 and fentanyl 2 micrograms kg-1 and maintained with propofol 5-7 mg kg-1 hr-1 to target the bispectral index between 40 and 50. After the bispectral index value had stabilized the propofol infusion rate was fixed. In the N2O group, the following concentrations of N2O were subsequently inhaled at 20-min intervals; 20, 40, 60 and 70%, and then N2O was terminated. In the ketamine group, ketamine (0.4 mg kg-1 + 1.0 mg kg-1h-1) was given. The bispectral index and 95% spectral edge frequency were recorded 20 min after each change in concentration of N2O or ketamine infusion. The bispectral index and 95% spectral edge frequency did not change significantly in the N2O group, but increased significantly from 44.1 +/- 0.7 and 16.0 +/- 0.5 to 58.6 +/- 1.4 and 19.5 +/- 0.3 (P < 0.01), respectively, in the ketamine group. Additional N2O or ketamine did not decrease the bispectral index and 95% spectral edge frequency values. The depth of sedation should be assessed carefully using a bispectral index monitor when these anaesthetic agents are used together.

Adult↗
PubMed1999

Hemodynamic and metabolic changes following cerebral revascularization in patients with cerebral occlusive diseases.

Changes in cerebral hemodynamics and metabolism following cerebral revascularization were evaluated using positron emission tomography (PET). Ten patients who had received nonsurgical treatment for 3-6 months for minor completed stroke underwent superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery. All patients showed no extensive infarction on MR, and responsible vascular lesions were detected in the anterior circulation. A PET study of cerebral blood flow (CBF), oxygen extraction fraction (OEF), cerebral metabolic rate for oxygen (CMRO2), and cerebral metabolic rate for glucose (CMRGlu) measurements was performed before and 1.5 months after surgery using a steady state technique. Angiographically, anastomotic sites were patent in all patients. Seven patients showed neurological improvement after surgery and the others showed no improvement. The decreases in CBF, CMRO2 and CMRGlu recovered to some extent not only on the lesion side but also on the contralateral side after surgery. The increase in OEF values on the lesion side subsequently decreased after surgery. CMRO2 and CMRGlu showed parallel changes. It is concluded that the metabolic improvement afforded by the cerebral revascularization resulted in the neurological improvement, and that PET study is a powerful method for evaluating patients with cerebral occlusive diseases.

Aged↗
PubMed1999

Inhibitory effect of clonidine on ketamine-induced norepinephrine release from the medial prefrontal cortex in rats.

We have investigated the effect of clonidine on ketamine-induced norepinephrine release from the medial prefrontal cortex in rats using microdialysis. Twenty-one male Wistar rats weighing 200-300 g were allocated randomly to one of four groups: i.p. injection of ketamine 100 mg kg-1 with clonidine 0 (saline: group C0, n = 6), 3 (group C3, n = 5), 30 (group C30, n = 5) and 300 micrograms kg-1 (group C300, n = 5). As reported previously, ketamine increases norepinephrine release. In groups C0 and C3, marked increases in norepinephrine release were observed with maximum values of mean 483 (SEM 55)% and 412 (53)% compared with basal values, respectively. Although significant increases in norepinephrine release were also observed (276 (43)%) in group C30, they were significantly lower than those in groups C0 and C3 (P < 0.01 and P < 0.05, respectively). In group C300, there was a significant reduction in norepinephrine release (62 (13)%) compared with basal and the three other groups (P < 0.01). This inhibitory effect of clonidine on norepinephrine may be related to reduction in undesirable emergence reactions after ketamine anaesthesia.

Adrenergic alpha-Agonists↗
PubMed1999

The spectrum of mutations in UBE3A causing Angelman syndrome.

Angelman syndrome (AS) is characterized by mental retardation, absence of speech, seizures and motor dysfunction. AS is caused by maternal deletions for chromosome 15q11-q13, paternal uniparental disomy (UPD), imprinting defects or loss-of-function mutations in the UBE3A locus which encodes E6-AP ubiquitin-protein ligase. The UBE3A gene is imprinted with paternal silencing in human brain and similar silencing of the Ube3a locus in Purkinje cells and hippocampal neurons in the mouse. We have sequenced the major coding exons for UBE3A in 56 index patients with a clinical diagnosis of AS and a normal DNA methylation pattern. The analysis identified disease-causing mutations in 17 of 56 patients (30%) including 13 truncating mutations, two missense mutations, one single amino acid deletion and one stop codon mutation predicting an elongated protein. Mutations were identified in six of eight families (75%) with more than one affected case, and in 11 of 47 isolated cases (23%); no mutation was found in one family with two siblings, one with a typical and one with an atypical phenotype. Mutations were de novo in nine of the 11 isolated cases. An amino acid polymorphism of threonine substituted for alanine at codon 178 was identified, and a 3 bp length polymorphism was found in the intron upstream of exon 8. In all informative cases, phenotypic expression was consistent with imprinting with a normal phenotype when a mutation was on the paternal chromosome and an AS phenotype when a mutation was on the maternal chromosome. Laboratory diagnosis and genetic counseling for AS are complex, and mutation analysis is valuable in clinically typical AS patients with a normal methylation analysis.

Angelman Syndrome↗
PubMed1999

Expression of inducible nitric oxide synthase in human cultured endometrial stromal cells.

The aim of the present study was to investigate the expression of mRNA and protein for inducible nitric oxide synthase (iNOS) in human cultured endometrial stromal cells. The endometrial stromal cells were cultured in the absence or the presence of cytokines such as interleukin (IL)-1beta and interferon (IFN)-gamma, which are inherently detectable in the endometrium. Nested reverse transcription-polymerase chain reaction detected iNOS mRNA in stromal cells cultured without cytokines. Northern blot analysis failed to detect iNOS mRNA in stromal cells cultured for 9 h in the absence of cytokines or in the presence of IL-1beta (10-100 ng/ml) or IFN-gamma (10-1000 U/ml) alone, but could detect iNOS mRNA cultured in combinations of IL-1beta and IFN-gamma. The concentrations of iNOS mRNA were increased as early as 3 h after the addition of the cytokine combination and persisted for up to 36 h. Western blot analysis demonstrated iNOS protein in stromal cells cultured for 12 h with combined IL-1beta and IFN-gamma. These results raise the possibility that nitric oxide locally synthesized by iNOS may be involved in the control of endometrial functions.

Adult↗
PubMed1999

Volatile anesthetics augment expression of proinflammatory cytokines in rat alveolar macrophages during mechanical ventilation.

BACKGROUND: Previous studies indicate that anesthesia and surgery induce an inflammatory reaction in alveolar macro phages. However,they filed to independently evaluate the relative contributions of factors including mechanical ventilation, general anesthesia, and surgical stress. Therefore, the authors tested the hypothesis that inflammatory reactions at the cellular level in alveolar macrophages are induced within 2 h of inhalation of volatile anesthetics under mechanical ventilation. METHODS: After administration of pentobarbital, rats were allocated to the nonventilated control or spontaneous or mechanical ventilation (n = 15/group) for 2 h at a fraction of inspired oxygen (FI(O2)) of 0.21. In a separate series of experiments, rats were mechanically ventilated without volatile anesthesia, or during exposure to halothane, enflurane, isoflurane, or sevoflurane (n = 15/group). Pulmonary lavage was performed, and RNA was extracted from harvested cells. The mRNA for the proinflammatory cytokines interleukin (IL)-1alpha, IL-1beta, IL-6, macrophage inflammatory protein-2 (MIP-2), interferon gamma (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha) were measured by semiquantitative reverse transcription-polymerase chain reaction using beta-actin as an internal standard. Pulmonary lavage concentrations of these cytokines were measured by enzyme-linked immunoassay. RESULTS: The lavage cell count and cytology were similar in each series of the experiment. Gene expression of MIP-2 and TNF-alpha was greater during mechanical than spontaneous ventilation and nonventilation control However, the concentrations of cytokines except MIP-2 and TNF-alpha were less than detection levels. During exposure to volatile anesthetics, gene expression for IL-1beta, MIP-2, IFN-gamma, and TNF-alpha all increased significantly compared with mechanical ventilation alone. Significant increases in lavage concentrations of MIP-2 and TNF-alpha were also observed. CONCLUSIONS: Gene expression of proinflammatory cytokines increase after inhalation of volatile anesthetics under mechanical ventilation. These data indicate that inhalation of volatile anesthetics under mechanical ventilation induces an inflammatory response at the transcriptional level within 2 h.

Anesthetics, Inhalation↗
PubMed1999

Preventive effect of matrix metalloproteinase inhibitor, R-94138, in combination with mitomycin C or cisplatin on peritoneal dissemination of human gastric cancer cell line TMK-1 in nude mice.

R-94138, a matrix metalloproteinase inhibitor, was examined for the ability to prevent peritoneal dissemination of a human gastric cancer xenograft, TMK-1. When the supernatant of a co-culture of TMK-1 cells and human normal fibroblast cells was subjected to gelatin zymography, it was clear that the protein expression of MMP-2 had been inhibited by R-94138. When TMK-1 was injected intraperitoneally (i.p.) into nude mice at 5 x 10(5) cells/body, the resulting peritoneal dissemination mimicked clinical carcinomatous peritonitis. When the maximum tolerated dose of mitomycin C (MMC) or cisplatin (DDP) was given 12 h after the tumor inoculation, peritoneal dissemination was completely inhibited, while the effect of R-94138 was limited when it was given i.p. at a dose of 20 mg/kg in a schedule of q.d. x 5 starting 12 h after tumor injection. MMC and DDP also suppressed peritoneal dissemination when they were administered 1 week after the tumor inoculation at a single dose of 2 and 3 mg/kg i.p., respectively. R-94138 inhibited peritoneal dissemination when it was administered i.p. at a dose of 30 mg/kg in a schedule of q.d. x 5 starting from 1 week after tumor injection. The combination of MMC and R-94138 increased the preventive effect on peritoneal dissemination. R-94138 seems to be a promising candidate to prevent peritoneal dissemination of gastric cancer.

Acetamides↗
PubMed1999

Epileptic spasms preceded by partial seizures with a close temporal association.

PURPOSE: To investigate the distinctive features of patients with West syndrome who had partial seizures followed by epileptic spasms (PS-ES). METHODS: We examined 45 patients with West syndrome whose epileptic spasms were recorded with simultaneous video-electroencephalography (EEG) monitoring between 1982 and 1996. We investigated the patients who had PS-ES and compared the PS-ES patients with the 37 patients without PS-ES. RESULTS: Of the 45 patients who had epileptic spasms in clusters (ES) and hypsarrhythmia on the interictal EEG, eight (17%) had ES preceded by partial seizures (PS) with a close temporal association. Seven of these eight were female patients. The underlying disorders were tuberous sclerosis (one patient), Aicardi syndrome (one), nonketotic hyperglycinemia (one), and focal cortical dysplasia (one). The etiology was unknown in the remaining four patients, but was suspected to be of prenatal origin in three. Three types of seizure sequence were identified: PS followed several seconds later by ES (two patients), alternating PS and ES starting with PS (three), and PS gradually replaced by ES with overlapping of the two (three). PS-ES disappeared or was replaced by other types of seizures in 1-34 months. Six patients could not walk, and all patients could not speak any sentences at age 3 years. CONCLUSIONS: Compared with patients without PS-ES, those with PS-ES more often had organic brain lesions of prenatal origin, other types of seizures before the onset of ES, asymmetric hypsarrhythmia on the EEG, and poor psychomotor outcome.

Age of Onset↗
PubMed1999

Characterization of a novel missense mutation in the pore of HERG in a patient with long QT syndrome.

INTRODUCTION: A new strategy to elucidate the molecular mechanisms underlying the long QT syndrome (LQTS) is now available with genetic mutational analyses and characterization of ion channel mutations. METHODS AND RESULTS: In a 26-year-old woman with LQTS, we identified a novel missense mutation in the pore of HERG by using polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP) and sequencing of her genomic DNA. The mutation resulted in an amino acid substitution of a positively charged lysine for a highly conserved uncharged asparagine at codon 629 (N629K). Whole cell, patch clamp studies were conducted in COS7 cells by transfecting with wild-type (WT) and/or the mutant N629K HERG. The WT HERG produced an I(Kr)-like, E-4031-sensitive conductance with an inward rectification. In contrast, the cells transfected with the N629K HERG did not display any time-dependent current. Cotransfection of WT and N629K HERG (at a ratio of 1:1) produced a significantly smaller conductance when compared with WT HERG (WT 59.9 +/- 7.3 pA/pF [n = 22] vs WT+N629K 5.5 +/- 2.3 pA/pF [n = 11]; P < 0.01), but did not alter K+ ion selectivity and tail current-voltage dependence. Because aprindine hydrochloride was effective in preventing ventricular tachycardias, we also tested the effect of the drug on WT HERG (I(Kr)) and KvLQT1/KCNE1 (I(Ks)) currents expressed in COS7. CONCLUSION: Functional analyses of a novel missense mutation in the pore of HERG suggest that the mutation causes marked reduction of I(Kr) via a dominant negative effect.

Adult↗
PubMed1999

Prevalence of human papillomavirus infection in women attending a sexually transmitted disease clinic.

The purpose of this study was to determine the prevalence of infection due to human papillomavirus (HPV) types of high and intermediate oncogenic risk, which was most frequently associated with uterine cervical neoplasia. The subjects were 236 prostitutes who visited a sexually transmitted diseases (STD) clinic in a metropolitan area in 1998. Another 95 women who visited a university hospital were selected as a normal control group. A swab sample collected from the uterine cervix and external os was subjected to hybrid capture assays for low-oncogenic-risk HPV types (HPV A; including types 6, 11, 42, 43 and 44) and high- and intermediate-oncogenic-risk HPV types (HPV B; including 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68). Chlamydia trachomatis and Neisseria gonorrhoeae. Fisher's exact test was used for statistical analyses. Among the microorganisms tested, the positive rate for HPV B was the highest both in the women attending the STD clinic (STD group) and in the control group. The positive rate for HPV B in the STD group was 47.5% (112 of 236), and this was significantly higher than the 5.3% (5 of 95) in the control group (p < 0.0001). These findings suggest that HPV examination is recommended for women who visit an STD clinic to assess the future risk of cervical neoplasia.

Adolescent↗