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Biomedical subjects

R Kobayashi

Publications and source records attributed to R Kobayashi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Differences in electroencephalogram power densities between genuine narcolepsy and secondary narcolepsy.

Diagnosing narcolepsy is not always simple. Some patients secondarily show narcoleptic tetrad through irregular sleep patterns or psychotic diseases. The power densities of daytime electroencephalograms in genuine narcolepsy and secondary narcolepsy were analysed and compared. Electroencephalogram power densities for a 6.5-h period after waking in genuine narcoleptic patients were lower than those of secondary narcoleptic patients in the 11.0-12.5 Hz bands. Arousal levels may be lower in genuine narcoleptic patients than in secondary narcoleptic patients. Spectral analysis may be useful in clarifying differences between the two groups.

Adolescent↗
PubMed2000

Autonomic nervous function after evening bright light therapy: spectral analysis of heart rate variability.

In order to investigate the effects of 5000 lx evening bright light on autonomic nervous function, a spectral analysis was used to assess heart rate variability in consecutive 5-min epochs just after 60 min of bright light therapy was given to 12 young women (range: 20-21 years of age). The study revealed that a low frequency band (LF) increased in bright light conditions (BL) in comparison with controlled conditions (CL). High frequency band (HF), LF:HF ratio and the coefficient of variance (CV R-R) were not significantly different between the two conditions. These results indicate that 5000 lx evening bright light may affect sympathetic nervous system activity in healthy women.

Adult↗
PubMed2000

Effect of short duration morning bright light in elderly men: sleep structure.

Sleep structure was measured in five healthy elderly men in their homes. The subjects were exposed to bright light (6000 lx) for 30 min in the morning or instructed to sit in front of a desktop lighting device without light. Relative to the control conditions, bright light exposure significantly decreased time in bed and the number of awakenings. Rapid eye movement sleep was significantly fragmented by stage 1 sleep in the control condition compared with the bright light condition. These findings indicate that a short duration of morning bright light changes sleep structure and is effective in maintaining sleep.

Aged↗
PubMed2000

Effect of Helicobacter pylori eradication on malignant transformation of gastric adenoma.

BACKGROUND: A nonrandomized trial of Helicobacter pylori eradication was conducted in patients with endoscopically diagnosed gastric adenoma to determine the long-term effect of antimicrobial treatment on progression of the adenoma. METHODS: Of 64 patients with an endoscopically diagnosed gastric adenoma and H pylori infection, 32 were treated with omeprazole and antibiotics to eradicate the infection, and 32 were not. RESULTS: During 2 years of follow-up, 4 (12.5%) of the 32 patients in the untreated group developed an early stage, intestinal-type gastric cancer, whereas no gastric cancer was found in the 32 patients in the treated group. CONCLUSION: H Pylori eradication may inhibit progression of gastric adenoma to carcinoma.

Adenoma↗
PubMed2000

Intravenous detergent poisoning.

CASE REPORT: In the literature regarding surfactant poisoning, the route of exposure has almost always been oral. We report a case in which about 40 mL of bath detergent for home use was self-injected. The primary pathophysiologic effects were relative hypovolemia and cardiac dysfunction. The patient experienced frequent ventricular tachycardia, acute renal failure, rhabdomyolysis, hemolysis, and coagulation dysfunction. Intensive care included the administration of antiarrythmial agents and hemodialysis. The patient survived and was discharged from our hospital without sequelae.

Acute Kidney Injury↗
PubMed2000

Detection of lymphocytes productively infected with Epstein-Barr virus in non-neoplastic tonsils.

Epstein-Barr virus (EBV) persists for life in the infected host. Little is known about EBV reactivation and regulation of virus persistence in healthy individuals. We examined tonsils of chronic tonsillitis patients to detect EBV transcripts, EBV genomes and lytic proteins. LMP1 transcripts were observed in 11 of 15 specimens and BZLF1 transcripts were detected in six. Multiple copies of EBV genome equivalents per cell, and ZEBRA- and viral capsid antigen-positive cells were also detected in tonsillar lymphocytes. These results indicate that EBV productively infected cells may survive in the face of immune surveillance in the tonsils. Thus, EBV replication may occur in tonsillar lymphocytes, and tonsillar lymphoid tissues may play a role in the maintenance of EBV load in vivo.

DNA, Viral↗
PubMed2000

The human SWI-SNF complex protein p270 is an ARID family member with non-sequence-specific DNA binding activity.

p270 is an integral member of human SWI-SNF complexes, first identified through its shared antigenic specificity with p300 and CREB binding protein. The deduced amino acid sequence of p270 reported here indicates that it is a member of an evolutionarily conserved family of proteins distinguished by the presence of a DNA binding motif termed ARID (AT-rich interactive domain). The ARID consensus and other structural features are common to both p270 and yeast SWI1, suggesting that p270 is a human counterpart of SWI1. The approximately 100-residue ARID sequence is present in a series of proteins strongly implicated in the regulation of cell growth, development, and tissue-specific gene expression. Although about a dozen ARID proteins can be identified from database searches, to date, only Bright (a regulator of B-cell-specific gene expression), dead ringer (a Drosophila melanogaster gene product required for normal development), and MRF-2 (which represses expression from the cytomegalovirus enhancer) have been analyzed directly in regard to their DNA binding properties. Each binds preferentially to AT-rich sites. In contrast, p270 shows no sequence preference in its DNA binding activity, thereby demonstrating that AT-rich binding is not an intrinsic property of ARID domains and that ARID family proteins may be involved in a wider range of DNA interactions.

Amino Acid Sequence↗
PubMed2000

Genotyping of feline MHC (FLA) class II DRB by PCR-RFLP method using group-specific primers.

For genotyping of feline major histocompatibility complex (FLA) class II DRB, the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method using group-specific primers was tried. Sixty-six DRB genes were classified into 8 groups according to differences in the first 5' amino acid sequences. The group-specific primers were designed as forward ones, which were specific for 5' base sequences of genes in each group. Three to 7 appropriate restricted enzymes were selected by computer analysis for RFLP typing of the genes divided into each group. In 6 out of 9 cats, the results of DRB typed by direct sequence method agreed with results of the PCR-RFLP method using group-specific primers. In the other 3 cats, the number of genes amplified by group-specific primers was I or 2 more than those detected by direct sequence method. The direct sequence method in 9 cats identified 5 new FLA-DRB genes. The PCR-RFLP method using group-specific primers could divide 66 genes into 37 genes and 10 subgroups from the RFLP pattern. One to 6 genes in each cat, and a total of 203 genes and subgroups were detected in 68 domestic cats. The genes detected might be biased to the subgroup G1-1a (28.8%), DRB*0501 (10.3%), G1-2a (9.4%) and G6b (7.4%). The PCR-RFLP method using group-specific primers may be useful in typing FLA class II DRB.

Animals↗
PubMed2000

Squamous cell carcinoma of the oral cavity in an infant cynomolgus monkey.

Squamous cell carcinoma was observed in the oral cavity in a one-year-old male cynomolgus monkey. Histopathologically, the tumor consisted of various shaped cells and its assemblies infiltrated into the surrounding connective tissues. Although no obvious metaplastic keratinized cancer pearls were found in the tumor cells, the intercellular bridges were observed. Immunohistochemically, tumor cells were stained with anti-keratin, but not with anti-vimentin. On virological examinations, no papilloma virus antigen or Epstein-Barr Virus small mRNA could not be detected. Under the electron microscope, incomplete tonofibrils and desmosomes in the cytoplasm and microvillus of the cell membrane were observed, suggesting a malignancy or low differentiation of the tumor cells in the present case. This is the first case of squamous cell carcinoma observed in very young macaques, to our knowledge.

Animals↗
PubMed2000

[Mycobacterial infection within a pulmonary bulla].

The patient was a 31-year-old man. Chest X-ray films and computed tomographic (CT) scans disclosed fluid retention within an 11-cm diameter pulmonary bulla that had been detected in the upper lobe of his left lung 1 year earlier. CT films also disclosed a 1.5-cm nodular lesion in the apical segment of the left lower lobe. The patient had no symptoms and laboratory examinations disclosed no signs of inflammation. Thoracoscopic examination revealed a yellow-turbid fluid with caseous necrosis within the bulla. Although Ziehl-Neelson staining of a bulla tissue specimen was 1 on the Gaffky scale, culture of the fluid was negative. Histologically, the bulla wall and pulmonary nodule revealed granuloma with caseous necrosis, thus yielding a diagnosis of mycobacterial infection within the bulla and lung. Following an operation, anti-tuberculous drugs were administered and the patient was well without recurrence of tuberculosis 30 months afterward. We concluded that infectious bulla with few or no symptoms and limited inflammatory findings may occasionally be caused by Mycobacterium infection.

Adult↗
PubMed2000

[Low body mass index and exercise capacity in patients with chronic obstructive pulmonary disease (COPD)].

This study examined retrospectively the relationships between body weight and exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Seventeen patients with a %FEV1 less than 55% (mean +/- SD 36% +/- 8.8%) and minimum body weights of the body mass index (BMI) less than 20 (17.3 +/- 1.7) performed incremental exercise testing using a treadmill. Seventeen %FEV1-matched control patients with normal body weights were selected. There were no significant differences in the patients' characteristics or their pulmonary function tests (including vital capacity, carbon monoxide diffusing capacity, and arterial blood gases). Low BMI patients Is this the weaning of (67.8 +/- 6.3 years old) were younger than the control patients (73.1 +/- 8.5 years old), but the difference was not statistically significant. The exercise capacities of low BMI patients were significantly superior to those of the control patients (316.5 +/- 171.5 seconds vs 204.1 +/- 116.3 seconds, p = 0.038) and total walking distance without statistical significance (194.9 +/- 117.0 m vs 125.7 +/- 98.0 m, p = 0.071). Also, low BMI patients achieved higher maximal minute ventilation volume during exercise than the controls. The major factor limiting exercise in patients with low BMI was ventilation. Moderately low body weight may not be a risk factor in Japanese COPD patients.

Aged↗
PubMed1999

The RCAF complex mediates chromatin assembly during DNA replication and repair.

Chromatin assembly is a fundamental biological process that is essential for the replication and maintenance of the eukaryotic genome. In dividing cells, newly synthesized DNA is rapidly assembled into chromatin by the deposition of a tetramer of the histone proteins H3 and H4, followed by the deposition of two dimers of histones H2A and H2B to complete the nucleosome-the fundamental repeating unit of chromatin. Here we describe the identification, purification, cloning, and characterization of replication-coupling assembly factor (RCAF), a novel protein complex that facilitates the assembly of nucleosomes onto newly replicated DNA in vitro. RCAF comprises the Drosophila homologue of anti-silencing function 1 protein ASF1 and histones H3 and H4. The specific acetylation pattern of H3 and H4 in RCAF is identical to that of newly synthesized histones. Genetic analyses in Saccharomyces cerevisiae demonstrate that ASF1 is essential for normal cell cycle progression, and suggest that RCAF mediates chromatin assembly after DNA replication and the repair of double-strand DNA damage in vivo.

Amino Acid Sequence↗
PubMed1999

Purification and characterization of human RNPS1: a general activator of pre-mRNA splicing.

Biochemical purification of a pre-mRNA splicing activity from HeLa cells that stimulates distal alternative 3' splice sites in a concentration-dependent manner resulted in the identification of RNPS1, a novel general activator of pre-mRNA splicing. RNPS1 cDNAs, encoding a putative nucleic-acid-binding protein of unknown function, were previously identified in mouse and human. RNPS1 is conserved in metazoans and has an RNA-recognition motif preceded by an extensive serine-rich domain. Recombinant human RNPS1 expressed in baculovirus functionally synergizes with SR proteins and strongly activates splicing of both constitutively and alternatively spliced pre-mRNAs. We conclude that RNPS1 is not only a potential regulator of alternative splicing but may also play a more fundamental role as a general activator of pre-mRNA splicing.

Alternative Splicing↗
PubMed1999

Identification of the cell cycle regulator VCP (p97/CDC48) as a substrate of the band 4.1-related protein-tyrosine phosphatase PTPH1.

The human band 4.1-related protein-tyrosine phosphatase PTPH1 was introduced into NIH3T3 cells under the control of a tetracycline-repressible promoter. Ectopic expression of wild type PTPH1 dramatically inhibited cell growth, whereas a catalytically impaired mutant showed no effect. To identify the direct target of PTPH1 in the cell, we generated a substrate-trapping mutant, in which an invariant aspartate residue was changed to alanine (D811A in PTPH1). The PTPH1-D811A mutant trapped primarily a 97-kDa tyrosine-phosphorylated protein, which was determined to be VCP (also named p97 or yeast CDC48), from various cell lysates in vitro. However, when expressed in mammalian cells, the D811A mutant was observed to contain high levels of phosphotyrosine and did not trap substrates. Mutation of tyrosine 676 to phenylalanine (Y676F) in the PTPH1-D811A mutant led to a marked reduction in phosphotyrosine content. Furthermore, this double mutant specifically trapped VCP in vivo and recognized the C-terminal tyrosines of VCP, whose phosphorylation is important for cell cycle progression in yeast. Like wild type PTPH1, this double mutant also inhibited cell proliferation. Moreover, induction of wild type PTPH1 resulted in specific dephosphorylation of VCP without changing the overall phosphotyrosine profile of the cells. VCP has been implicated in control of a variety of membrane functions, including membrane fusions, and is a regulator of the cell cycle. Our results suggest that PTPH1 may exert its effects on cell growth through dephosphorylation of VCP, thus implicating tyrosine phosphorylation as an important regulator of VCP function.

3T3 Cells↗
PubMed1999

ACF consists of two subunits, Acf1 and ISWI, that function cooperatively in the ATP-dependent catalysis of chromatin assembly.

The assembly of core histones and DNA into periodic nucleosome arrays is mediated by ACF, an ISWI-containing factor, and NAP-1, a core histone chaperone, in an ATP-dependent process. We describe the isolation of Drosophila acf1 cDNA, which encodes the p170 and p185 forms of the Acf1 protein in ACF. Acf1 is a novel protein that contains two PHD fingers, one bromodomain, and two new conserved regions. Human WSTF, which is encoded by one of multiple genes that is deleted in Williams syndrome individuals, is the only currently known mammalian protein with each of the conserved motifs in Acf1. Purification of the native form of Acf1 led to the isolation of ACF comprising Acf1 (both p170 and p185 forms) and ISWI. Native Acf1 did not copurify with components of NURF or CHRAC, which are other ISWI-containing complexes in Drosophila. Purified recombinant ACF, consisting of Acf1 (either p185 alone or both p170 and p185) and ISWI, catalyzes the deposition of histones into extended periodic nucleosome arrays. Notably, the Acf1 and ISWI subunits function synergistically in the assembly of chromatin. ISWI alone exhibits a weak activity that is approximately 3% that of ACF. These results indicate that both Acf1 and ISWI participate in the chromatin assembly process and suggest further that the Acf1 subunit confers additional functionality to the general 'motor' activity of ISWI.

Adenosine Triphosphatases↗