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H Komatsu

Publications and source records attributed to H Komatsu.

At least 181 records · Page 10Linked to original sources
PubMed1997

[dl-Camphor Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material of dl-camphor was examined for the preparation of the "dl-Camphor Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained are as follows: UV spectrum, lambda max = 290 nm; IR spectrum, the same as that of the present JP Camphor Reference Standard (Control 953); melting point, 179.1 degrees C; purity test by gas-chromatography (GC), three kinds of impurities were detected; assay by GC, 99.8%. Based on the above results, the candidate raw material was authorized as the dl-Camphor Reference standard (Control 961) National Institute of Health Sciences (Japanese Pharmacopoeia).

Camphor↗
PubMed1997

[Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material for chlormadinone acetate was tested for preparation of the "Chlormadinone Acetate Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 215. 3 degrees C; UV spectrum, lambda max = 283.5 nm; IR spectrum, the same as that of JP Chlormadinone Acetate Reference Standard (Control 885); optical rotation, [alpha]20D = -13.0 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, two impurities were detected; loss on drying, 0.01%; assay, 99.4% by spectrophotometry and 99.5% by HPLC. Based on the above results, the raw material was authorized as the Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Chlormadinone Acetate↗
PubMed1996

Ethanol-enhanced permeation of phosphatidylcholine/ phosphatidylethanolamine mixed liposomal membranes due to ethanol-induced lateral phase separation.

Effects of ethanol on permeability of large unilamellar vesicles (ca. 160 nm in diameter), composed of dipalmitoyl phosphatidylcholine/dilauroyl phosphatidylethanolamine (DLPE) mixture, were studied by monitoring leakage of the fluorescent dye, calcein, entrapped in the inner aqueous phase of the vesicles. In the presence of 2.1 M ethanol, permeabilities of membranes in various phases were G (bilayer gel) phase > L (bilayer liquid-crystalline) phase with a high mole fraction of DLPE and (I (ethanol-induced interdigitated gel phase) + G) phase > (I + L) at 20 mol % DLPE. Arrhenius plots of the leakage rate constants demonstrated that the permeability was greater with 2.1 M ethanol than without ethanol, especially in the temperature above 33 degrees C, suggesting that the presence of ethanol can induce lateral phase separation of liposomal membranes and cause them to have a high permeability even if they are stable and have low permeability in its absence.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Efficacy of interferon in treating chronic hepatitis C in children with a history of acute leukemia.

Interferon (IFN) is effective in treating adults as well as children with chronic hepatitis C. We investigated the efficacy of IFN therapy in 13 children with underlying acute leukemia who had chronic hepatitis C (age range, 5 to 17 years; mean age, 9.9 years). Natural IFN- alpha was administered at a dose of 0.1 mega unit (MU)/kg (maximum dose, 6.0 MU) daily for 2 weeks and then three times per week for an additional 22 weeks (total dose, 8 MU/kg). IFN treatment was initiated at least 2 years after the completion of treatment for acute leukemia. A complete response was obtained in 5 children (38%). The serum level of anti-hepatitis C virus core antibody was closely related to the response to IFN. IFN therapy was well tolerated by all but 1 of the children, who developed mild transient heart failure 4 months after the initiation of therapy. IFN therapy for children with chronic hepatitis C who had underlying acute leukemia was beneficial. However, further trials are required to confirm the safety and improve the dosage schedule of IFN therapy.

Acute Disease↗
PubMed1996

Effects of glucose and its oligomers on the stability of freeze-dried liposomes.

The effects of glucose and its oligomers (maltodextrins) on the stability of sonicated liposomes during freeze-drying were studied by monitoring the retention of the fluorescent dye, Calcein, entrapped in the liposomal inner aqueous phase and by the use of differential scanning calorimetry (DSC). Glucose showed weak cryoprotective effects on dioleoylphosphatidylcholine (DOPC) or egg yolk phosphatidylcholine (eggPC) liposomes, while it had a relatively high cryoprotective effect on dipalmitoylphosphatidylcholine (DPPC) liposomes. Maltose and maltotriose showed high cryoprotective effects on eggPC liposomes, while other maltodextrin, longer oligomers, showed low cryoprotective effects. No saccharide was effective to protect DOPC liposomes. The fluidity and/or packing of lipid membranes had considerable influences on the stability of liposomes during the lyophilization. Maltodextrins showed relatively high cryoprotective effects on DPPC liposomes at low saccharide/lipid molar ratios, although the cryoprotective effects decreased with the increase in the molar ratios. Size measurements suggested that glucose and maltose completely prevented the aggregation and/or fusion of liposomes during lyophilization, and that other maltodextrins induced them due to their weak hydrophobic properties.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Sequence-selective carbohydrate-DNA interaction: dimeric and monomeric forms of the calicheamicin oligosaccharide interfere with transcription factor function.

The synthetic oligosaccharide moiety of the antibiotic calicheamicin and the head-to-head dimer of this oligosaccharide are known to bind to the minor groove of DNA in a sequence-selective manner preferring distinct target sequences. We tested these carbohydrates for their ability to interfere with transcription factor function. The oligosaccharides inhibit binding of transcription factors to DNA in a sequence-selective manner, probably by inducing a conformational change in DNA structure. They also interfere with transcription by polymerase II in vitro. The effective concentrations of the oligosaccharides for inhibition of transcription factor binding and for transcriptional inhibition are in the micromolar range. The dimer is a significantly more active inhibitor than is the monomer.

Aminoglycosides↗
PubMed1996

Modulation of Ca2+-activated K+ channels by Mg2+ and ATP in frog oxyntic cells.

Ca2+-activated K+ channels in the basolateral plasma membrane of bullfrog oxynticopeptic cells are intimately involved in the regulation of acid secretion. Patch-clamp techniques were applied to study the regulating mechanism of these channels. In the excised inside-out configuration, intracellular Mg2+ decreased channel activity in a dose-dependent manner. In the absence of Mg2+, administration of adenosine 5'-trisphosphate (ATP) to the cytoplasmic side also inhibited channel activity. On the other hand, in the presence of Mg2+, addition of ATP markedly increased channel activity. At a fixed concentration of free Mg2+, the Mg-ATP complex caused channel activation and shifted the dose response relationship between channel activity and the intracellular Ca2+ concentration to the left. A nonhydrolysable ATP analogue, adenosine 5'-[beta,gamma-imido]triphosphate (AMP-PNP) adenylyl [beta,gamma-methylene]diphosphate (AMP-PCP), could not substitute for ATP in channel activation, but a hydrolysable ATP analogue, adenosine 5'-O-(3-thiotriphosphate) (ATP[gammaS]) could do so. Furthermore, application of alkaline phosphatase to the cytoplasmic side inhibited channel activity. These results demonstrate that Ca2+-activated K+ channels are regulated by Mg2+ and ATP, and suggest that a phosphorylation reaction may be involved in the regulation mechanism of these channels.

Adenosine Triphosphate↗
PubMed1996

Is thrombomodulin useful as a tumor marker of a lung cancer?

To evaluate whether thrombomodulin (TM) can be considered a tumor marker of lung cancer, we examined serum TM levels in 179 lung cancer patients by an enzyme immunoassay. Further, in 91 resected cases, we also investigated the TM presence in lung cancer tissue by an immunohistochemical method. Our findings revealed that 58 (32%) of 179 lung cancer patients had higher serum TM levels than our cutoff levels. No difference was seen in the serum TM-positive ratio between histologic types, but patients with Stage IV disseminated cancer showed a higher serum TM-positive ratio than those with Stage I-IIIB localized cancer, especially cases of adenocarcinoma. Immunostaining results showed a TM presence in the cancer cells of 32 (35%) of 91 lung cancer cases. The TM presence in cancer cells was higher in cases with squamous cell carcinoma than with adenocarcinoma; no differences were seen among the disease stages. No correlation was found between the serum TM and the presence of TM in cancer cells. Further, serum TM status appears to have little clinical significance as a method to detect early lung cancer or for predicting the recurrence after the surgical excision of a lung cancer. Thus, we have concluded that, although serum TM levels are elevated in some lung cancer patients, it is doubtful that the TM status is useful as a tumor marker of lung cancer.

Adenocarcinoma↗
PubMed1996

(+/-)-3-[4-(2-dimethylamino-1-methylethoxy)-phenyl]-1H-pyrazolo[3,4- B]pyridine-1-acetic acid (Y-25510) stimulates production of IL-1 beta and IL-6 at the level of messenger RNA expression in cultured human monocytes.

(+/-)-3-[4-(2-Dimethylamino-1-methylethoxy)phenyl]-1H-pyrazolo[3, 4-b]pyridine-1-acetic acid (Y-25510) stimulated the mRNA expression for interleukin-1 beta (IL-1 beta), and enhanced the expression induced by lipopolysaccharide (LPS) in cultured human peripheral blood mononuclear cells (PBMC) and THP-1 cells, a cell-line derived from human monocytic leukemia. Y-25510 also stimulated the mRNA expression for IL-6 in both types of the cells, however, the stimulation required the presence of LPS. In THP-1 cells, the stimulation of IL-1 beta mRNA expression by Y-25510 was suppressed by cycloheximide, an inhibitor of protein synthesis. This phenomenon indicates that the stimulation requires de norv protein synthesis. In contrast, the stimulation of mRNA expression for IL-6 by Y-25510 was not suppressed by cycloheximide but suppressed by N alpha-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK), an inhibitor of nuclear transcription factor-kappa B (NF-kappa B) activation, in the presence of LPS, suggesting that the stimulation requires NF-kappa activation. These results demonstrate that Y-25510 stimulates the mRNA expression for IL-1 beta and IL-6 by different mechanisms. Dexamethasone suppressed the LPS-induced expression of mRNA for IL-1 beta and IL-6 in THP-1 cells, whereas the drug never suppressed the mRNA expression for these cytokines in the presence of Y-25510. The result indicates that Y-25510 stimulates the mRNA expression for IL-1 beta and IL-6 by different mechanisms from those of LPS.

Culture Media↗
PubMed1996

Mutations in a cyclic nucleotide-gated channel lead to abnormal thermosensation and chemosensation in C. elegans.

The C. elegans tax-4 mutants are abnormal in multiple sensory behaviors: they fail to respond to temperature or to water-soluble or volatile chemical attractants. We show that the predicted tax-4 gene product is highly homologous to vertebrate cyclic nucleotide-gated channels. Tax-4 protein expressed in cultured cells functions as a cyclic nucleotide-gated channel. The green fluorescent protein (GFP)-tagged functional Tax-4 protein is expressed in thermosensory, gustatory, and olfactory neurons mediating all the sensory behaviors affected by the tax-4 mutations. The Tax-4::GFP fusion is partly localized at the sensory endings of these neurons. The results suggest that a cyclic nucleotide-gated channel is required for thermosensation and chemosensation and that cGMP is an important intracellular messenger in C. elegans sensory transduction.

Amino Acid Sequence↗
PubMed1996

Surface representation in the visual system.

Perception of surface accompanies the impression that a certain area of the visual field is occupied by some quality, such as color, brightness and transparency. This does not mean, however, that information about surface quality must be obtained throughout the area. It has been shown in many situations that our visual system has ability to interpolate information obtained at the border of the surface and to perceive homogeneous surfaces. The most dramatic demonstration of this is the perceptual filling-in at the blind spot. In order to understand the neural representation of surface in the visual system, we conducted a series of experiments using macaque monkeys. First, we examined if neurons in the primary visual cortex (V1) respond when a homogeneous surface is presented on the receptive field. Neurons representing the parafoveal visual field were tested and it was found that about one third of neurons showed significant responses when the cell's receptive field was contained in a homogeneous surface. Then we examined neuron activities in the retinotopic representation of the blind spot in V1. Although there is no retinal input in the blind spot, a homogeneous surface is perceived within the blind spot as a result of filling-in. We tested whether neurons in this region were activated when a homogeneous surface was perceived in the blind spot as a result of filling-in. We found some neurons in V1 were activated by stimuli which lead to the filling-in. These results indicate that when a surface area is perceived, neurons are activated throughout the region in V1 topographically corresponding to the perceived surface and not restricted to the region representing the border of the surface.

Animals↗
PubMed1996

Binding properties of human immunodeficiency virus type-2 (HIV-2) RNA corresponding to the packaging signal to its nucleocapsid protein.

The nucleocapsid (NC) protein of human immunodeficiency virus type-1 (HIV-1) contains two zinc finger motifs (ZFMs), and binds specifically to the packaging signal which is located in the 5' leader sequence of the viral genomic RNA between the first splice donor and the gag initiator codon (AUG). In this study, we analyzed the specificity of the binding of the corresponding region of HIV-2 (Region 3) to its NC protein (NCp8), by performing a competitive ultraviolet (UV) cross-linking assay using in vitro-synthesized 32P-labeled and unlabeled RNAs corresponding to a sequence between the primer binding site and the gag AUG (Region 1). Binding of 32P-labeled Region 1 RNA to NCp8 was inhibited specifically by adding unlabeled Region 1 and 3 RNAs and no specific binding was detected using deletion mutant peptides of NCp8. These findings suggest that the region(s) which bind(s) specifically to HIV-2 NCp8 lie(s) between the first splice donor and the gag AUG in the 5' leader sequence and that NCp8 is the minimum binding region responsible for the specific binding of the region downstream of the first splice donor site of HIV-2 RNA.

Amino Acid Sequence↗
PubMed1996

Multiple but different genetic factors underlie enflurane and isoflurane requirements studied through backcross analysis in C57BL and ddN mice.

We performed a classic backcross analysis to examine the basic genetic nature of enflurane (ENF) and isoflurane (ISO) anesthetic requirement in two inbred mice strains, C57BL (BL) and ddN. We have previously reported different ENF and ISO anesthetic requirements in these two strains. BL (n = 22) and ddN (n = 26) mice were used as parents and were reciprocally crossed to produce F1 hybrid mice. Each F1 offspring was crossed to its parent to produce backcross siblings (BF1). Anesthetic end point was determined as the loss of righting reflex. Measurement of anesthetic requirement was performed during 8-12 wk after birth. Although ddN mice showed slightly less resistance to ENF and ISO compared with our previous report, they were more resistant than BL mice. Multivariate regression analysis of parents' and F1 hybrids' data revealed that, while maternal factors and factors on autosomes were related to both anesthetics, the factors on the X chromosome were ENF specific. A wide variation in anesthetic requirements among BF1 progeny suggested multifactorial inheritance. The regression equations obtained did not always predict anesthetic requirement in BF1 progeny. These discrepancies may be due to the epistatic interaction of related genes. We conclude that multiple but different genetic factors are involved in determining ENF and ISO anesthetic requirements in BL and ddN mice.

Anesthetics, Inhalation↗
PubMed1996

Effects of 3,6-dimethylpyrazine-2-thiol on reproductive and accessory reproductive organs in male rats.

The weights of prostate and seminal vesicle were decreased by treatment with 3,6-dimethylpyrazine-2-thiol(3,6-DMP-SH) but the weights of testes and the plasma testosterone levels were not changed. The recovery of the weight of prostate and seminal vesicles of testosterone-treated orchidectomized rats were inhibited by treatment with 3,6-DMP-SH. Direct injection of 3,6-DMP-SH into accessory reproductive organs also induced the decrease in the weight of relevant organs. Administration of oxendrone or chlormazinone along with 3,6-DMP-SH decreased the weights of accessory reproductive organs more than administration of only one substance. In vitro uptake of testosterone into prostate and seminal vesicle were blocked by the presence of 3,6-DMP-SH. These results suggest that 3,6-DMP-SH directly inhibited testosterone uptake into the accessory reproductive organs.

Androgen Antagonists↗
PubMed1996

Estimations of average particle sizes and size distributions of commercially available human-insulin aqueous suspensions using laser-light diffraction spectroscopy.

The average diameter and size distribution of particles in commercially available isophane-insulin and zinc-insulin aqueous suspensions (11 products) were examined using laser-light diffraction spectroscopy (LLDS). Wide variation was observed between products in volume-weighted and number-weighted average diameters. The particles in the insulin aqueous suspensions were found to be mono-dispersed within relatively narrow size distributions. Sonication for a short time led to a downshift in the apparent average diameter, which was most remarkable with isophane-insulin aqueous suspensions. This could be ascribed to dispersion of aggregated needle-like crystals and/or crystal breakage. In the case of biphasic isophane-insulin aqueous suspensions, the average size as well as the size distribution shifted toward the smaller end of the scale with decrease in the isophane content.

Humans↗
PubMed1996

[Anemia in elderly patients with malignant tumors].

Complications, prognosis, and efficacy of treatments were retrospectively studied in elderly patients, some of whom had lung, stomach, colon, pancreatic, and liver cancers. Hemoglobin concentration and characteristics of erythrocytes were measured for up to sixty months. Eighty-eight patients died of cancer, and malignant tumors were detected before death in 57. The average survival periods were 11 months for patients with gastric cancer. 9 months for those with colon cancer, and 7 months for those with lung cancer. Malignancies of the digestive organs and lung were often detected in elderly patients with anemia. In elderly people who were without cancer for more than 78 months the hemoglobin concentration did not change significantly, but in those with a malignancy the hemoglobin concentration continuously decreased. Patients with colon cancer who were given blood transfusions survived longer than those who were not given the transfusions, but the same was not true of patients with gastric or lung cancers. Iron therapy, however, was generally effective in patients with malignant tumors of the gastrointestinal tract. Among those who were near death, the red cell distribution widths differed significantly between patients with different types of carcinomas, but differences in mean corpuscular hemoglobin and in mean corpuscular volume were not statistically significant. In conclusion, hemoglobin concentration and characteristics of erythrocytes should not be neglected in the diagnosis and treatment of cancers in the elderly.

Aged↗
PubMed1996

[Changes in erythrocyte structure and in platelets in elderly patients with disseminated intravascular coagulation].

We measured the platelet distribution width, the mean platelet volume, the volume percentage of platelets, and the platelet-to-large-cell ratio in 15 elderly patients with disseminated intravascular coagulation (DIC). Peripheral venous blood mixed with ehtylenediaminetetraacetic acid was analyzed with a Sysmex E-4000 analyzer. The underlying diseases were sepsis, pneumonia, pyelonephritis, and other inflammatory diseases. The mean duration of survival from the onset of DIC was 16.9 +/- 23.9 days. The distribution of red cell sizes before the onset of DIC did not differ significantly from that in patients without DIC, but fragmentation of erythrocytes on blood films was more common in the early stage of DIC (p < 0.01). Before the onset of DIC, the two groups did not differ significantly in the frequency of giant platelets on blood smears. At the onset of DIC, the platelet distribution width, the mean platelet volume, and the platelet-to-large-cell ratio were significantly higher than in patients without DIC. The concentration of glutamic-oxaloacetic transaminase and those of other serum enzymes did not change significantly, but the serum creatinine concentration and the blood urea nitrogen level increased as the platelet-to-large-cell ratio increased. No significant relation was evident between the levels of serum C-reactive protein and creatinine, between the platelet-to-large-cell ratio and the mean volume of red blood cells, or between the platelet-to-large-cell ratio and the distribution of red cell sizes. These data suggest that studies of platelets are more useful in the diagnosis of DIC at early stages of impaired organ function than are other indicators of inflammation such as the level of C-reactive protein.

Aged↗