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Biomedical subjects

K Kanai

Publications and source records attributed to K Kanai.

At least 37 records · Page 2Linked to original sources
PubMed1999

Clinical implications of mutations C-to-T1653 and T-to-C/A/G1753 of hepatitis B virus genotype C genome in chronic liver disease.

Among many mutational "hot spots" on hepatitis B virus (HBV) genome, A-to-T1762 and G-to-A1764 within the core promoter have been underscored in view of disease association as well as viral expression/replication. Although to a lesser extent, C-to-T1653 and T-to-V(C/A/G)1753 were also noteworthy in our previous study. To assess the clinical significance of these mutations, we determined the nucleotide sequence of an HBV DNA fragment covering these sites in HBsAg-positive blood donors (n = 160) and patients with chronic hepatitis (n = 66), liver cirrhosis (n = 45), and hepatocellular carcinoma (n = 58), most of whom were infected with genotype C HBV (subtype adr). In cases where HBe antigen was positive, the frequency of T1653 and/or V1753 showed a striking increment from chronic hepatitis patients (18%) to liver cirrhosis and/or hepatoma patients (82%), whereas that of T1762/A1764 was already high in chronic hepatitis patients (76%). In HBe antigen-negative cases, by contrast, significant difference in the frequency of T1653/V1753 mutants was found between blood donors (22%) and chronic hepatitis patients (67%). Our results suggest that T1653/V(particularly C)1753 mutants are more closely associated than T1762/A1764 with the progression of liver disease from chronic hepatitis to cirrhosis in HBe antigen-positive patients. A system of site-directed mutagenesis PCR RFLP was constructed to diagnose T1653 and C/A1753 more conveniently. Detecting T1653 and C/A1753 by this method would contribute to the differential diagnosis of HBV-associated liver disease.

Base Sequence↗
PubMed1999

Genotypes of TT virus (TTV) compared between liver disease patients and healthy individuals using a new PCR system capable of differentiating 1a and 1b types from others*.

TT virus (TTV) lacks obvious pathogenicity; almost all of the infected hosts are symptom-free. A possibility remains, however, that certain strains can cause liver disease while most others are non-pathogenic. Genotypes 1 a and 1 b have been proposed to contain such pathogenic strains. To test this possibility, we constructed a PCR system capable of detecting TTV of the 1 a and 1 b genotypes differentially from the other genotypes, and compared the frequencies of these genotypes between patients with liver disease of unknown etiology (n=42) and healthy individuals (n=50). The assay comprised 3 steps: i) PCR to amplify a 3.2-kb fragment using universal primers; ii) 2nd-round PCR, starting from the 3.2-kb amplicon, for a approximately 280-nt fragment by use of genotype 1-specific primers; and iii) digestion of the approximately 280-nt amplicon with MboI and BanI to discriminate between 1 a and 1 b. Eventually, 40 (95%) of the patients and 47 (94%) of the controls were positive for the 3.2-kb amplicon, and the 1 a, 1 b, 1 a+1 b, and non-1 genotypes of TTV were found in 2 (5%) vs 4 (9 percent), 5 (13%) vs 4 (9%), 1 (3%) vs 1 (2%) and 32 (80%) vs 38 (81%) of the 40 patients and 47 controls, respectively: the distribution was almost identical between the two groups. The hypothesis that the genotype 1 of TTV may be more closely associated with liver disease than other genotypes was not supported by this study.

Base Sequence↗
PubMed1999

Efficacy of NND-502, a novel imidazole antimycotic agent, in experimental models of Candida albicans and Aspergillus fumigatus infections.

In vitro and in vivo anti-Candida albicans and anti-Aspergillus fumigatus activities of NND-502, a new imidazole-antimycotic, were compared with those of fluconazole (FCZ), itraconazole (ITZ) and/or amphotericin B (AmB). NND-502 exhibited strong in vitro antifungal activity against both fungal species; its MIC against C. albicans was 1-4 times lower than that of FCZ, and its MIC against A. fumigatus was at least 60-2000 times lower than that of ITZ and AmB. In vivo antifungal treatments with each drug were initiated 1 h after inoculation in the experimental models, so that antifungal potential reflected prophylactic activity rather than therapeutic activity. The oral regimen of NND-502 in a murine model of systemic C. albicans infection was much less effective than that of FCZ. In vivo anti-A. fumigatus activity of oral NND-502 in a murine model of systemic infection was apparently superior to that of FCZ and ITZ in terms of prolonging survival. In addition to the murine model of systemic aspergillosis, intravenous NND-502 was shown to be highly effective in a rat model of pulmonary aspergillosis compared with intravenous AmB; 90% of animals survived at a dose of 2.5 mg/kg per day of NND-502 while only 30% of animals escaped death when 5 mg/kg per day of AmB was used. This potent efficacy of NND-502 was also confirmed in a sublethal challenge study in which the administration of the agent at a dose as low as 1.25 mg/kg per day resulted in the significant reduction of organisms in the lung; no comparable effect of AmB was found.

Amphotericin B↗
PubMed1999

Selective agars for the isolation of Streptococcus iniae from Japanese flounder, Paralichthys olivaceus, and its cultural environment.

Two kinds of selective agar were developed for the isolation of Streptococcus iniae, the causal agent of streptococcosis, from Japanese flounder (Paralichthys olivaceus) and from culture tanks in flounder farms. The selective agars were heart infusion agar with added thallium acetate and oxlinic acid (TAOA), and colistin sulphate and oxolinic acid (CSOA). For samples containing various bacterial flora, selective agars were supplemented with defibrinated horse blood in order to distinguish beta-haemolytic colonies of Strep. iniae. Streptococcus iniae was quantitatively isolated from the brain and kidney of diseased flounders in pure culture. Two-thirds of isolates picked up from selective blood agars inoculated with intestinal samples were identified as Strep. iniae. The bacterial colony numbers of deposits and water from culture tanks on selective blood agars were about 10-10(5) times smaller than those on control heart infusion agar; Strep. iniae was isolated from few deposit and water samples.

Agglutination Tests↗
PubMed1999

Inhibition of sterol 14 alpha-demethylation of Candida albicans with NND-502, a novel optically active imidazole antimycotic agent.

To investigate the mode of action of the newly synthesized optically active imidazole compound, NND-502, (-)-(E)-[4-(2, 4-dichlorophenyl)-1,3-dithiolan-2-ylidene]-1-imidazolylacetonit rile, its effect on ergosterol biosynthesis in cell-free extracts of Candida albicans was examined and compared with that of the (S)-enantiomer of NND-502 in addition to lanoconazole and bifonazole, both of which are clinically used for the treatment of dermatomycoses. NND-502 was found to interfere with ergosterol biosynthesis by inhibition of sterol 14alpha-demethylase, while no interference due to the (S)-enantiomer of NND-502 was found, indicating that the stereochemical orientation of the 2, 4-dichlorophenyl group plays an important role in the interaction with the enzyme. In terms of drug concentration exerting 50% inhibition of ergosterol biosynthesis, NND-502 was 2.5 and 28 times more effective than that of lanoconazole and bifonazole, respectively.

Antifungal Agents↗
PubMed1999

Suppressive activity of a macrolide antibiotic, roxithromycin, on pro-inflammatory cytokine production in vitro and in vivo.

This study was designed to examine the influence of a macrolide antibiotic, roxithromycin (RXM), on the production of pro-inflammatory cytokines, interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. In the first experiments, we examined the effect of RXM on in vitro cytokine production from lipopolysaccharide (LPS)-stimulated human peripheral blood monocytes. The monocytes were cultured in the presence of various doses of the agent. After 24 h, the culture supernatants were obtained and assayed for IL-1beta and TNF-alpha contents by enzyme-linked immunosorbent assay. RXM suppressed the in vitro production of IL-1beta and TNF-alpha in response to LPS stimulation. This was dose dependent and first noted at a concentration of as little as 0.05 microg/ml, which is much lower than therapeutic blood levels. In the second part of the experiments, we examined the influence of RXM on the appearance of IL-1beta and TNF-alpha in mouse lung extract induced by LPS inhalation. RXM was administered orally into BALB/c mice at a single dose of 2.5 mg/kg once a day for 5-12 weeks. These mice were then instilled with LPS into the trachea and examined for the presence of cytokines in aqueous lung extracts. Pretreatment of mice with RXM for 5 weeks did not influence of the appearance of both IL-1beta and TNF-alpha in aqueous lung extracts. However, pretreatment for more than 7 weeks dramatically suppressed the cytokine appearance in the extracts.

Administration, Inhalation↗
PubMed1999

Spontaneous lymphoma in a Japanese White rabbit.

Lymphoma was observed in a 4-month-old female Japanese White rabbit. Grossly, the markedly enlarged mesenteric lymph nodes, prominent Peyer's patches of jejunum, splenomegaly, and enlargement of tracheobronchial lymph nodes, adrenal glands and ovaries were observed. Histologically, neoplastic lymphoid cells proliferated diffusely showing frequent mitotic figures and a characteristic 'starry sky' appearance. Their basophilic cytoplasm contained a few lipid droplets. The mesenteric lymph nodes, Peyer's patches of jejunum, and tracheobronchial lymph nodes were largely replaced by the tumor tissues. The stomach, small intestines, especially the jejunum, liver, spleen, ovaries, and adrenal glands were heavily infiltrated with neoplastic cells. These results suggest that the present lymphoma may have originated from the gastrointestinal lymphoid tissue.

Animals↗
PubMed1998

Hepatitis C virus infection and mutations of mannose-binding lectin gene MBL.

We assessed the genetic polymorphism of mannose-binding lectin (MBL) in 93 patients with chronic hepatitis C (45 responders and 48 nonresponders to interferon) and 218 healthy controls. Mutant allele was identified only at codon 54 (Gly-->Asp), leading to three genotypes (54 m/m, 54 W/m, and 54 W/W). Frequency of 54 m/m was significantly lower in interferon-responders (2.2%), compared to those in nonresponders (14.6%) and controls (10.6%): p < 0.05. Our results suggest that homozygous carriage of the variant allele of codon 54 of MBL may predict poor response to interferon in chronic hepatitis C patients.

Adult↗
PubMed1998

High-dose (9 MU) long-term (60 weeks) alfa-interferon therapy for chronic hepatitis patients infected with HCV genotype 1b.

Efficacy of standard regimens (e.g., 3-6 MU for 24 weeks) of alfa-IFN therapy for chronic hepatitis C has been limited, particularly in patients with HCV/1b. To see if higher-dose longer term treatment is more effective, we tried a 9 MU 60-week regimen. HCV/1b-infected chronic hepatitis patients received 9 MU IFN alpha 2a everyday but Sunday for 2 weeks and thrice a week for next 10 weeks, and 76 patients became HCV RNA-negative while 81 remained positive. The RNA-negative patients were then randomized to receive 3 MU (group I, n = 37) or 9 MU (group II, n = 39) for 48 weeks. Of the RNA-positive patients, only those with normal ALT received another 9 MU 48-week treatment (group III, n = 45). Sustained responders (SR) were defined as those with negative RNA and normal ALT 6 months after the therapy. SR rates based on intent-to-treat principle did not differ significantly between groups I and II (30% vs 41%), but those based on the protocol-compatible cases showed a significantly lower than those in group II. Adverse effects of IFN, developed more frequently in groups II and III than in group I, were mostly reversible. In conclusion, our results encourage 9 MU 60-week IFN alpha treatment in HCV/1b-infected patients with careful attention to adverse effects, and suggest that the treatment should be discontinued if HCV RNA does not disappear within 12 weeks.

Genotype↗
PubMed1998

Fibroblast-migration in a wound model of ascorbic acid-supplemented three-dimensional culture system: the effects of cytokines and malotilate, a new wound healing stimulant, on cell-migration.

To assess the migratory response of fibroblasts in vitro, normal human dermal fibroblasts (NHDF) were cultured in the presence of L-ascorbic acid 2-phosphate to induce a multilayered structure. Round wounds were made by punching, and the migratory response was evaluated by counting the number of migrating cells in the wounded areas. Collagenase activity in the culture-medium was then measured. When the wound model was treated with bFGF, IL-1 alpha or PDGF, the migratory response was facilitated with increased collagenase secretion. In contrast, treatment with TGF-beta reduced the migratory response and collagenase secretion. Since the multilayered structure is rich in collagenous matrix, degradation of the matrix by secreted collagenase is probably necessary for the cells to migrate into the wounded areas. Furthermore, malotilate, which is now under development as an agent for wound therapy, facilitated the migratory response of NHDF with increased collagenase secretion in this wound model, suggesting that the wound healing effect of malotilate is in part attributable to stimulated migration of fibroblasts to wounded areas subsequent to extracellular matrix-degradation.

Ascorbic Acid↗
PubMed1997

Response to interferon-alpha 2a in patients with e antigen-negative chronic hepatitis B.

Sixty-eight consecutive patients with chronic hepatitis B received 702 million units of recombinant interferon-alpha 2a. Of the 24 patients negative for hepatitis B e antigen (HBeAg) in serum, the normalization of serum transaminase occurred in 14 (58%) at the completion of interferon therapy and in 13 (54%) at 12 months thereafter; it was normalized in 17 (39%) and 13 (30%), respectively, of the 44 HBeAg-positive patients. Of the HBeAg-negative patients, hepatitis B virus DNA was cleared from serum in six (25%) at the completion and in one (4%) at 12 months thereafter, in contrast to only one (2%, p < 0.05) and none of the HBeAg-positive patients, respectively. The 1896th nucleotide of G (G1896) for codon 28 for tryptophan or A (A1896) for the stop codon 28 in the precore region was determined by restriction fragment length polymorphism. The ten HBeAg-negative patients with A1896 only in the precore region had lower pretreatment levels of viral markers, which decreased more rapidly and extensively after interferon than in the 14 HBeAg-negative patients with a mixture of G1896 and A1896 or in the 44 HBeAg-positive patients. These results indicate that patients with HBeAg-negative chronic hepatitis B may respond better to interferon than HBeAg-positive patients, and that the precore mutant with the stop codon 28 may be sensitive to interferon.

Adult↗
PubMed1997

Effect of intraluminal pressure on the intimal thickening in injured rabbit carotid arteries in an organ-culture system.

We developed an organ culture system in order to examine the effect of intraluminal pressure on intimal thickening in injured arteries. After endothelial denudation, an excised rabbit common carotid artery was incubated at 37 degrees C in a glass bottle perfused with Dulbecco's modified Eagle medium containing 10% fetal calf serum at a constant flow rate of 6 ml/h at various static pressure of 60, 95, 130, 165, or 200 cmH2O. Intimal thickening, which consisted of smooth muscle cells and extracellular matrix, increased in a time- and pressure-dependent manner up to 130 cmH2O. Excessive pressured (165 and 200 cmH2O), however, caused necrosis in the media. These results suggest that a rise in intraluminal pressure accelerates intimal thickening in injured arteries.

Animals↗
PubMed1997

Long-lasting muscle relaxant activity of eperisone hydrochloride after percutaneous administration in rats.

Potency and duration of muscle relaxant activity of eperisone hydrochloride were examined after percutaneous administration in the intercollicular decerebrated rat rigidity model and compared to those of eperisone after intravenous injection. A continuous movement was loaded on the hindlimb of the rat model to maintain stable rigidity. The tonus of the hindlimb was recorded by EMG from the triceps surae and was quantified by using the public domain NIH Image program. Eperisone ointment administered percutaneously showed significant muscle relaxant activity at 8.4 cm2 (4.2 mg of eperisone)/rat. The effect was dose-dependent and lasted over 60 min. Intravenously injected eperisone showed significant activity at 1.25 mg/kg, but the decrease of tone was lost within 30 min after injection. Plasma eperisone levels were monitored in the same model, and they were well correlated to the dosage. These results suggest that percutaneously administered eperisone is absorbed efficiently and shows potent and long-lasting muscle relaxant activity.

Administration, Cutaneous↗
PubMed1997

Studies on the antifungal activity of the new imidazole antimycotic lanoconazole in infected sites. Distribution in the skin and in vitro activity in the presence of stratum corneum.

To answer the question why topically applied lanoconazole (CAS 101530-10-3, NND-318) is so highly effective in the treatment of dermatomycoses in both animal models and human patients, the antifungal activity of lanoconazole in infected sites was investigated. 1. Distribution of lanoconazole in rat skin: The distribution of lanoconazole within the dorsal skin of rats was examined by measurement of radioactivity and microscopic autoradiography. 24 h after dermal application of 14C-lanoconazole cream formulation, 83% of the total radioactivity in the skin was recovered from the stratum corneum, and thereafter the radioactivity decreased gradually up to 96 h. Metabolite analysis showed that more than 94% of the extractable radioactivity was lanoconazole itself after 24 and 48 h. Microautoradiograms of the skin also supported the radioactivity distribution. 2. In vitro antifungal activity in stratum corneum-containing medium: Candida albicans TIMM 2640 was incubated for 10 days at 27 degrees C in a vitamin-supplemented yeast carbon base medium containing 5 mg/ml of human stratum corneum and different concentrations of lanoconazole or bifonazole (CAS 60628-96-8, reference agent). Compared with the control culture, lanoconazole strongly inhibited fungal growth in a concentration dependent manner at concentration above 0.1 microgram/ml, resulting in a reduction of viable cell recovery to less than 50% after 10 days. The inhibitory activity of bifonazole was clearly weaker than that of lanoconazole. At concentrations of 0.1-10 micrograms/ml lanoconazole reduced keratinolytic acid proteinase activity in the culture-supernate to 40-70% of the control value, while bifonazole showed 50% reduction of the activity at a concentration of 10 micrograms/ml. These results indicate that lanoconazole is mainly distributed and retained in the stratum corneum after topical application where it exerts strong antifungal activity.

Administration, Topical↗
PubMed1997

Specific binding of Burkholderia pseudomallei cells and their cell-surface acid phosphatase to gangliotetraosylceramide (asialo GM1) and gangliotriaosylceramide (asialo GM2).

Specific binding between bacterial cells and host tissue is an early step of the pathogenesis of infection. Burkholderia pseudomallei cells, the causative micro-organisms of melioidosis, were demonstrated to bind specifically to tissue glycolipids (asialo GM1 and asialo GM2) by solid phase binding assay on thin layer chromatograms. The detection limit was around 400 pmol of the glycolipids. Acid phosphatase purified from the culture filtrate of B. pseudomallei was tested for such binding properties, and the same results were obtained. According to our previous studies, the enzyme is a glycoprotein located on the cell surface, and hydrolysed tyrosine phosphate most actively among the substrates so far tested. The mode of binding between the enzyme and the glycolipids was analyzed by comparison of binding levels among three samples different in protein content, sugar content and specific phosphatase activities per protein and sugar residue. The results suggested the possibility of a receptor-ligand relationship between the bacterial enzyme and the host-cell glycolipids (asialo GM).

Acid Phosphatase↗
PubMed1996

A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map.

The 718,122 base pair sequence of the Escherichia coli K-12 genome corresponding to the region from 12.7 to 28.0 minutes on the genetic map is described. This region contains at least 681 potential open reading frames, of which 277 (41%) have been previously identified, 147 (22%) are homologous to other known genes, 139 (20%) are identical or similar to the hypothetical genes registered in databases, and the remaining 118 (17%) do not show a significant similarity to any other gene. In this region, we assigned a cluster of cit genes encoding multienzyme citrate lyase, two clusters of fimbrial genes and a set of lysogenic phage genes encoding integrase, excisionase and repressor in the e14 genetic element. In addition, a new valine tRNA gene, designated valZ, and a family of long directly repeated sequences, LDR-A, -B and -C, were found.

DNA, Bacterial↗