Biomedical subjects

K Kawasaki

Publications and source records attributed to K Kawasaki.

At least 19 recordsLinked to original sources

PubMed1992

Phenol-treatment and a homologous pairing-assay.

Homologous pairing is a key step in homologous genetic recombination. In the early stage of trials for the identification of homologous pairing-promoting proteins from a fission yeast, Schizosaccharomyces pombe, we treated DNA products with phenol in the presence of a salt for the removal of tightly bound proteins from DNA before the assay, but we found that this treatment caused very efficient protein-independent double-strand formation from complementary single-stranded DNAs. Using an assay including the phenol treatment, we detected another species of apparent homologous pairing-promoting proteins in the nuclei, in addition to a homologous pairing-promoting protein consisting of three components which we reported previously. However, studies involving the use of an assay without the phenol-treatments revealed that the second one was not really a homologous pairing-protein. Thus, the protein-independent double-strand formation by phenol-treatment in the presence of a salt could cause the erroneous identification of homologous pairing-promoting proteins.

Bacteriophages↗

PubMed1992

Membrane fusion of influenza virus with phosphatidylcholine liposomes containing viral receptors.

pH-dependent membrane fusion of influenza virus with liposomes made of phosphatidylcholine was studied by the spin-labelling method. Efficiency of viral fusion with liposomes composed of dimyristoyl phosphatidylcholine or dipalmitoyl phosphatidylcholine was considerably lower compared to dioleoyl phosphatidyl choline or egg yolk phosphatidylcholine, suggesting importance of unsaturation of acyl chains of lipid bilayers. Reconstitution of specific viral receptors such as Glycophorin or sialylparagloboside strongly enhanced fusion with liposomes composed of dimyristoyl phosphatidylcholine. A direct comparison between the activities of the receptors showed that Glycophorin was about 50 times more effective than sialyparagloboside at the same receptor/phosphatidylcholine molar ratio.

Animals↗

PubMed1992

Identification of two types of homologous DNA pairing activity in mouse cells.

We have identified two types of homologous DNA pairing activity in mouse cell extracts by a strand-transfer assay. Both activities are separated from each other by anion-exchange chromatography; neither of them needs ATP. One requires magnesium ion and is stimulated by Escherichia coli single-stranded DNA binding protein, whereas the other does not require the ion and shows a higher affinity for a left-handed Z-DNA.

Adenosine Triphosphate↗

PubMed1992

A multicomponent protein of a fission yeast that promotes joint molecule formation from homologous DNAs.

We developed a quantitative assay ("homologous pairing gel assay") adequate for the purification of the activity promoting the formation of joint molecules, an intermediate of homologous recombination ("homologous pairing"). With this assay, one can measure the extent of homologous pairing between a single-stranded DNA and a strand of 3H-labeled double-stranded DNA by crude enzyme preparations. Since the total activity did not significantly change during the sporulation process, we tried to purify the activity from a whole cell extract of mitotic cells of a fission yeast, (Schizosaccharomyces pombe). Through quantitative assaying of a single fraction or of mixed fractions, we obtained three fractions, all of which were required for the maximum level of the ATP-independent homologous pairing: Fractions 65, 100, and 30. In Fractions 100 and 30, polypeptides of approximately 100 and approximately 30 kDa (the 100- and 30-kDa polypeptides), respectively, were the sole detectable components. Fraction 65 contained a polypeptide of approximately 65 kDa (the 65-kDa polypeptide) as the major component and also small amounts of the 30- and 100-kDa polypeptides. Fraction 65 by itself promoted homologous pairing, but the reaction was saturated at a level of approximately 20% of the maximum level achieved with the recA protein. Even when added in excess, Fraction 30 or 100 alone did not promote detectable homologous pairing. A mixture of Fractions 65 and 100 at a rather strict optimum ratio only promoted homologous pairing, the level being 50-70% that with the recA protein, suggesting a stoichiometric complex of these polypeptides as the active form. Fraction 30 alone did not enhance the reaction with Fraction 65, but stimulated homologous pairing promoted by the optimum mixture of Fractions 65 and 100 to the maximum level achieved with the recA protein. Therefore, the homologous pairing-promoting protein from the fission yeast is likely to be a multicomponent protein.

Chromatography, Affinity↗

PubMed1992

A multicenter comparison of nicorandil and diltiazem on serum lipid, apolipoprotein, and lipoprotein levels in patients with ischemic heart disease.

The effects of nicorandil and diltiazem on serum lipid, apolipoprotein, and lipoprotein levels in 37 patients with ischemic heart disease were examined in a randomized, multicenter study. Nicorandil (n = 20, 10-40 mg/day, b.i.d.) and diltiazem (n = 17, 60-240 mg/day, b.i.d.) were administered for 12 weeks. Both nicorandil and diltiazem administration showed an effective antianginal effect. Diltiazem administration showed a significant hypotensive action. There were no significant changes in serum lipids, apolipoproteins, and lipoproteins for both nicorandil and diltiazem. There were no significant changes in body weight, uric acid, and fasting blood sugar levels during the test period for both drugs. These data show that nicorandil, like diltiazem, does not have any adverse effects on lipid metabolism and that it is a favorable drug to use as an agent for treating arteriosclerotic heart disease.

Aged↗

PubMed1992

Evaluation of retinal integrity in eyes with retained intraocular metallic foreign body by ERG and EOG.

In three eyes with a retained intraocular metallic foreign body, the neural retina and retinal pigment epithelial (RPE) integrity were evaluated by means of ERG (a-wave, b-wave, oscillatory potentials) and non-photic EOG responses from the RPE (hyperosmolarity response, Diamox response, bicarbonate response). All three cases were judged in an early stage of retinal impairment on the basis of a well-preserved or supernormal b-wave amplitude and showed good postoperative prognosis. Out of three non-photic responses from the RPE, only the bicarbonate response was preoperatively reduced in two out of the three eyes.

Adult↗

PubMed1992

Spectral characteristics of rapid off-response in congenital deuteranomaly in one of monozygotic female twins.

The spectral sensitivity of the rapid off-response in the electroretinogram was studied in monozygotic female twins. One case was diagnosed as congenital deuteranomaly, and the other was normal. The log ratio of the sensitivity at 480 nm to the sensitivity at 620 nm (log S480/S620) was within the deutan range in the first case and within the normal range in the second. The two case were determined to be different at the retinal receptor level by study of the rapid off-response. This result of the rapid off-response was consistent with the results of the psychophysical examinations.

Adult↗

PubMed1992

Methylation status of ribosomal RNA gene clusters in the flow-sorted human acrocentric chromosomes.

Southern blot analysis of the human acrocentric chromosomes that were flow-sorted from B-lymphoblastoid cell line GM130B revealed that the sensitivity of the ribosomal RNA (rDNA) gene clusters to the restriction enzyme NotI differs among these rDNA-containing chromosomes: the rDNA clusters of Chromosomes (Chr) 13, 14, and 15 are much more sensitive to NotI digestion than those of Chrs 21 and 22 in this particular cell line. Detailed analysis by use of methylation-sensitive enzymes HpaII and HhaI and methylation-insensitive enzyme MspI confirmed the significant variation in the methylation status of rDNA clusters among these chromosomes. Quantitative analysis by fluorescent in situ hybridization (FISH) indicated that copy number of rDNA varies among individual chromosomes, but the average copy number in the acrocentric Chrs 21 and 22 is significantly greater than that of the Chrs 13, 14, and 15 in GM130B cells. Similar analysis reveals that the methylation status of rDNA clusters in another B-lymphoblastoid cell line GM131 was different from that of GM130B. These data together indicate that the copy number and methylation patterns of rDNA clusters differ among individual acrocentric chromosomes in a given cell line, and they are different among cell lines.

Blotting, Southern↗

PubMed1992

Construction of a thermotaxis chamber providing spatial or temporal thermal gradients monitored by an infrared video camera system.

A thermotaxis chamber was constructed to quantitatively study thermotaxis in eukaryotic amoeboid cells. The apparatus provided either spatial or temporal temperature gradients in an observation chamber set in an inverted microscope. With an infrared video camera system, spatial thermal gradients were monitored directly and the temperature at the actual location of the cells could be estimated accurately. This enabled a precise determination of the strength of thermal stimuli. With this apparatus, we were able to simultaneously measure temperature and observe cellular behavior directly. This feature permits quantitative studies on stimulus-response relationships. The utility of the apparatus was demonstrated by thermotaxis assay under a spatial thermal gradient in polymorphonuclear leukocytes. Since this apparatus can also provide temporal thermal gradients, it may have several applications in studies of temperature-dependent phenomena in cell biology.

Amoeba↗

PubMed1992

Quantitative immunoelectron microscopic localization of Na, K-ATPase alpha-subunit in the epithelial cells of rat vestibular apparatus.

Na, K-ATPase was quantitatively localized in the epithelial cells of rat vestibular apparatus such as macula utriculi, macula sacculi and crista ampullaris. Immunogold localization method was carried out at the saturation level of antibody using an affinity purified antibody against the alpha-subunit of rat kidney Na, K-ATPase. Numerous gold particles were found on the basolateral membrane of the dark cells, a small number of gold particles were found on the basolateral membrane of the transitional epithelium cells and hair cells, but the luminal surface membranes of the hair cells, transitional epithelium cells, planum semilunatum cells and dark cells were rarely labeled by gold particles. Significance of the abundant localization of Na, K-ATPase on the basolateral surface of the dark cells in the production of endolymph was discussed.

Animals↗

PubMed1992

Shotgun polymerase chain reaction: construction of clone libraries specific to a NotI fragment of flow-sorted human chromosome 22.

We have developed the "shotgun polymerase chain reaction," a method for obtaining a large number of DNA markers specific to a giant DNA fragment, which facilitates analysis of a particular chromosomal region. We applied this method to a giant NotI fragment which carries the immunoglobulin lambda constant region on chromosome 22. NotI digests of chromosome 22 flow-sorted from human B-lymphoblastoid cell line GM130B were size fractionated by pulsed-field gel electrophoresis. Preliminary Southern hybridization analysis revealed that the immunoglobulin lambda constant region was conveyed on 1.4- and 1.3-Mb NotI fragments in this cell line. The agarose gel corresponding to 1.2 to 1.5 Mb in size was excised into slices and subjected to polymerase chain reaction to identify gel slices containing NotI fragments carrying Ke-Oz+, a subtype of the immunoglobulin lambda constant region. From the NotI fragment thus identified, a large number of small DNA segments were amplified through the ligation-mediated random polymerase chain reaction method. The amplified products were cloned and analyzed for chromosomal origin and localization to particular NotI fragments. Seven of eighteen clones originated from the 1.4-Mb NotI fragment of chromosome 22 in GM130B cells, which appears to be exactly the same as detected by a probe for the immunoglobulin lambda constant region.

Base Sequence↗

PubMed1992

Depletion of CD8 positive cells in nephrotoxic serum nephritis of WKY rats.

Following a small dose of nephrotoxic serum (NTS) WKY rats demonstrated crescentic glomerulonephritis, which was characterized by the early infiltration of CD8 positive cells in glomeruli. In vivo depletion of CD8 positive cells from WKY rats completely prevented proteinuria (4.6 +/- 4.8 mg/day vs. 105.3 +/- 11.6 mg/day on day 10; N = 19, P less than 0.001) and crescent formation (2.7 +/- 2.9% vs. 94.3 +/- 2.6%; P less than 0.001). Immunofluorescence revealed complete inhibition of the influx of CD8 positive cells and subsequent reduction of the infiltration of macrophages in the glomeruli. Glomerular binding of 125I-anti-rat glomerular basement membrane antibodies, host anti-rabbit IgG production and the C3 level in the circulation were the same as in the control. These data indicate that CD8 positive cells play a key role in glomerular injury and crescent formation. This model provides a useful system for studying the cellular mechanisms that lead to glomerular injury and subsequent crescent formation.

Animals↗

PubMed1992

Separate isolation of Clostridium difficile spores and vegetative cells from the feces of newborn infants.

A modified taurocholate-cefoxitin-cycloserine-fructose agar medium, pH 5.5, on which vegetative cells alone could grow, was newly devised for separate isolation of Clostridium difficile vegetative cells and spores from feces. The ratio of C. difficile-positive feces from healthy newborn infants younger than 10 days of the age was 30.8%, and 93.3% of feces from healthy infants older than 20 days were positive for C. difficile. C. difficile spores alone were detected in twenty-one samples (75%) of C. difficile-positive Twenty-eight specimens. Only 10.7% (3/28) C. difficile vegetative cells alone were detected. C. difficile spores alone were detected in one of nine healthy adults. These collective results offer potential explanations for high frequent isolations of C. difficile from newborn infants without occurrence of pseudomembranous colitis.

Bottle Feeding↗

PubMed1992

Caries experience in subjects 18-22 years of age after 13 years' discontinued water fluoridation in Okinawa.

The purpose of this study is to compare the state of teeth in young adults who had consumed fluoridated water from birth to 5-8 yr of age with the subjects who had non-fluoridated water. The sample consisted of 117 18-22-yr-old female nursing school students. The data obtained in dental examinations were sorted according to their place of residence, and then divided into groups depending on whether their place of residence had been supplied with fluoridated water or not. The fluoride concentration in the water had been 0.7-1.0 ppm in the six water supply systems which were under the control of the US military base. In the subjects who had fluoridated water, the following differences were found when compared to the control subjects: missing teeth and highly progressed caries occurred less frequently; significantly lower caries prevalence was present on free smooth and approximal surfaces; the overall DMFT differences in favor of the fluoridated subjects were small and non-significant.

Adolescent↗

PubMed1992

Intraocular kinetics of ceftazidime (Modacin).

The concentration of ceftazidime was determined in the aqueous humor and the vitreous body of normal, vitrectomized and aphakic/vitrectomized eyes and in the serum of albino rabbits 1 h after intravenous injection of 100 mg/kg ceftazidime. The intravitreal ceftazidime concentration was low (0.1-0.2 microgram/ml) in normal eyes 1 h after intravenous injection, and high (8.7 +/- 8.5 micrograms/ml) in vitrectomized and aphakic/vitrectomized eyes when injected immediately after surgery. The ceftazidime concentration was also determined in the aqueous humor and the vitreous body of normal eyes and in the serum of albino rabbits 3, 6, 12, 24 and 48 h after intravitreal injection of 200 micrograms. The intravitreal ceftazidime concentration after intravitreal injection decreased exponentially for 12 h (half-life about 7.4 h). It decreased more slowly thereafter and remained at 13.0 micrograms/ml (mean) even 48 h after injection. This concentration exceeded the minimum inhibitory concentrations against common gram-positive and gram-negative organisms causing endophthalmitis.

Animals↗

PubMed1992

Amino acids and peptides. XVI. Synthesis of N-terminal tetrapeptide analogs of fibrin alpha-chain and their inhibitory effects on fibrinogen/thrombin clotting.

N-Terminal tetrapeptide analogs of fibrin alpha-chain were synthesized by the solution method using a new active ester, the ester of the oxime of p-nitroacetophenone, and by the solid-phase method. Their inhibitory effects on fibrinogen/thrombin clotting were examined. Of the synthetic peptides, amide analogs of Gly-Pro-Arg-Pro exhibited a more potent inhibitory effect.

Amino Acid Sequence↗

PubMed1992

Effects of folinic acid on 5-fluorouracil induced cell lethality with or without cisplatin against head and neck laryngeal squamous carcinoma multicellular tumor spheroids.

We evaluated the efficacy of folinic acid (Leucovorin, LV) on cell lethality induced by 5-fluorouracil (FU) alone or in combination with cisplatin (DDP) by using the HEp-2 laryngeal squamous carcinoma multicellular tumor spheroids (MTS) system. For LV, non-toxic concentration of 10(-5) M was used. For cells in the monolayer, 6 and 24 h exposure to LV increased FU-induced cell lethality approximately 7- and 2-fold, respectively, whereas LV did not influence the effect of FU for MTS. LV's lack of effect on cells in MTS may be interpreted to mean that LV cannot penetrate the MTS. For the monolayer, simultaneous exposure to 3 drugs, DDP, FU and LV, produced synergistic interaction. However, sequential exposures were marginally synergistic or antagonistic, irrespective of sequence of DDP first or last. In contrast, DDP followed by FU plus LV was most synergistic for MTS. Simultaneous exposure was also synergistic, however, FU plus LV followed by DDP was antagonistic. These results suggest that LV is unable to penetrate into the MTS core to potentiate FU activity. DDP appears to have enhanced LV penetration into the MTS core. The exploration of means to overcome limited penetration of LV appears important for successful treatment of head and neck carcinoma.

Carcinoma, Squamous Cell↗

PubMed1992

Effects of lisinopril and low-dose trichlormethiazide on lipoprotein metabolism in patients with mild to moderate hypertension.

Fifty-six hypertensive patients were recruited to participate in a 12 week, randomised, multicentre trial to compare the effects of lisinopril (n = 31) and low-dose trichlormethiazide (n = 25) administration on blood pressure and lipoprotein metabolism. Both systolic and diastolic BPs decreased significantly after administration of lisinopril (5-40mg/day, mean dose 11 mg/day) and trichlormethiazide (2.0-4.0 mg/day, mean dose 2.2 mg/day). There were no significant changes in lipids, lipoproteins or apolipoproteins with either drug for 12 weeks and no significant differences between the two drugs for these parameters. It is concluded that lisinopril and low-dose trichlormethiazide administration are effective antihypertensive measures without any adverse effects after 12 weeks on lipoprotein metabolism in patients with mild to moderate essential hypertension.

Adult↗