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Biomedical subjects

K Kanai

Publications and source records attributed to K Kanai.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cloning of hepatitis C virus genomes and their properties.

A random primed lambda gt11-cDNA library was constructed from donors plasma presumably infected by blood-borne non-A, non-B hepatitis (hepatitis C:HC) agent and immunoscreened with serum pooled from patients with acute or chronic HC. Twelve lambda gt11-cDNA clones were isolated that was shown to encode antigens associated specifically with HC infection in Japan as well as in USA. Of these two, as well as another clone which is specific only to Japanese HC infection, have unique nucleotide sequences and were extensively studied. They are not derived from host DNA and have no homology to the sequences of known human viruses including hepatitis A, B and D viruses, Ebstein-Barr virus, coxsackievirus, immunodeficiency virus type 1 or Japanese encephalitis virus. These results suggest that they are derived from the genome of HC agent(s). In addition, of these, one clone seems to encode epitopes derived from both the core and the surface polypeptides of the agent.

Antigens, Viral↗
PubMed1990

Two distinct types of inwardly rectifying K+ channels in bull-frog atrial myocytes.

1. Single atrial myocytes were enzymatically isolated from the bull-frog as previously described (Hume & Giles, 1981), and patch-clamp techniques were used in an attempt to identify and separate two inwardly rectifying K+ channels in this tissue. 2. Single-channel measurements consistently demonstrated the existence of two different resting K+ channels, which both exhibited strong inward rectification. The unitary conductances of these K+ channels were 34 +/- 4 and 22 +/- 3 pS (mean +/- S.D., at 22-24 degrees C) when measured with 110 mM-K+ in the pipette solution, and their mean open times were 0.87 +/- 0.33 and 129.9 +/- 49.4 ms, respectively. 3. In the absence of acetylcholine (ACh) in the pipette, openings of the larger channels with the shorter open times occurred at a very low frequency. When ACh was present in the patch pipette, the activity of this channel increased significantly, although the single-channel conductance and gating behaviour were very similar either with or without ACh in the pipette. 4. The zero-current voltage (extrapolated from the inward currents through these types of channels) depended on the extracellular K+ concentration. [K+]o, in the fashion expected for a predominantly K(+)-selective channel: it shifted by 58 mV for a tenfold change in [K+]o. Very similar results were obtained from whole-cell voltage-clamp measurements (53 mV for a tenfold change in [K+]o). 5. The conductance of both types of K+ channels depended on [K+]o. The single-channel conductances were 25 +/- 3 and 13 +/- 2 pS with 50 mM [K+]o, and 19 +/- 4 and 9 +/- 2 pS with 20 mM [K+]o, respectively. 6. These results demonstrate that two types of resting inwardly rectifying K+ channels can be identified in single atrial myocytes. One of these is an inwardly rectifying K+ channel (IK1) previously identified in whole-cell voltage-clamp experiments (Hume & Giles, 1983). The second channel is the muscarinic receptor-regulated K+ channel (IK(ACh) which was first described in mammalian nodal and atrial cells. 7. N-Ethylmaleimide (NEM), a reagent which alkylates sulphydryl groups, affects these two types of K+ channels differentially. In the cell-attached patch configuration, bath application of NEM (50 microM) completely abolished the activity of IK(ACh), without affecting the IK1 channel activity. 8. To obtain further evidence that these two currents, IK1 and IK(ACh), were different, the inside-out patch-clamp technique was used.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed1990

In vitro susceptibilities of Pseudomonas pseudomallei to 27 antimicrobial agents.

Clinical isolates of Pseudomonas pseudomallei isolated in Thailand from 1981 to 1989 were tested for their in vitro susceptibilities to 27 antimicrobial agents, including older and newer quinolones, broad-spectrum cephems, carbapenems, monobactams, penicillins, tetracyclines, chloramphenicol, rifamycin, sulfamethoxazole, trimethoprim, and fosfomycin. Tosufloxacin, meropenem, CS-533, and minocycline were active against P. pseudomallei at levels comparable to or even greater than those of antimicrobial agents tested in previous studies, such as ciprofloxacin, ceftazidime, imipenem, carumonam, and piperacillin. Drug-resistant P. pseudomallei was found in only 1% of the isolates. The drug-resistant P. pseudomallei isolates displayed a unique pattern of susceptibility to the above-listed drugs.

Anti-Bacterial Agents↗
PubMed1990

Microphotometric analysis of cytochrome P-450 in periportal, midzonal, and perivenular hepatocytes of mice treated with phenobarbital.

To obtain detailed information on the increase of cytochrome P-450 (P-450) content in periportal, midzonal, and perivenular hepatocytes after phenobarbital (PB) administration, and to study the mechanism of increased P-450 in the endoplasmic reticulum (ER), we estimated microphotometrically the P-450 content and morphometrically the area of ER in hepatocytes of three zones from mice injected with 35, 50, 100, or 150 mg/kg of PB for 3 days. The amount of P-450 per unit cytoplasmic volume and the number of P-450 molecules per unit ER area (P-450 number) were increased by injection of 50, 100, or 150 mg/kg, and the ER area per unit cytoplasmic volume was increased by injection of 100 or 150 mg/kg, in hepatocytes from all three zones. Thus, the amount of P-450 in hepatocytes appeared in general to increase multiplicatively by simultaneous increases in both the P-450 number and the ER area. Furthermore, we could recognize two general types of relationship in the P-450 number and ER area between the patterns of change and the increasing doses: (a) increase in the P-450 number without ER proliferation (active type) in periportal and perivenular hepatocytes after injection of low doses; and (b) increase in ER proliferation without increase in the P-450 number (passive type) in hepatocytes of all three zones after injection of high doses.

Animals↗
PubMed1990

Immunofluorescence, enzyme-linked immunosorbent assay, particle agglutination and western blot for the detection of antibody to human immunodeficiency virus type 1.

Immunofluorescence assay (IFA) has been applied for detection of antibody to human immunodeficiency virus type 1 (HIV-1). To compare the IFA with an enzyme-linked immunosorbent assay (ELISA) and particle agglutination (PA), we examined the antibody response to HIV-1 in 475 sera from AIDS, PGL and ARC patients as well as several risk groups and healthy persons by three methods. The positive results by any methods were confirmed by western blot (WB). The results by all methods were well correlated on the sera from 45 asymptomatic male homosexuals and 70 female prostitutes. There were some false positive results by ELISA in the sera from prisoners and healthy persons. Four sera from drug abusers were positive only by PA and IFA and were negative by ELISA. All were WB-inconclusive. Particle agglutination and IFA results were compared with western blot analysis on 208 ELISA-positive sera. All IFA-strongly positive sera (84%) were positive by western blot. The sera with weakly positive, negative and inconclusive results by IFA (16%) were possibly any of positive, inconclusive or negative by western blot. By PA, 200 of 208 (97%) sera were PA-positive and 1% of these sera were WB-inconclusive while the PA-negative sera were either negative or inconclusive by western blot. These results suggested that PA is a simple and sensitive method for screening of HIV-1 antibody while IFA could be a primary confirmatory test and western blot would then be used for confirming any IFA-negative or inconclusive results.

Agglutination Tests↗
PubMed1989

Partial purification of a growth factor synthesized by a rat hepatoma cell line established in serum-free medium.

A rat hepatoma cell line was established from primary culture using RPMI 1640 without supplements. Hepatomas were induced in rats by 0.06% 3'-methyl-4-dimethylaminoazobenzene. An established cell line, FF101, has been maintained as a monolayer for longer than 34 months and subcultured for 42 passages. The population-doubling time was 78 h. The modal chromosome number was 66. FF101 was transplantable, and morphological examination of the transplanted tumors revealed a mixed type of hepatocellular and cholangiocellular carcinoma. FF101 retained the ability to express tyrosine aminotransferase and glucose-6-phosphatase. Also, FF101 synthesized alpha-fetoprotein. FF101-conditioned medium stimulated DNA synthesis and proliferation of several cell lines such as AH66, K562, and BALB/c3T3. The growth-promoting activity of FF101-conditioned medium was abolished by protease, dithiothreitol, acidic treatment, and heating. Gel filtration of conditioned medium on Sephacryl S-200 disclosed the growth-promoting activity at the molecular size of approximately 60,000 Da, and the isoelectric point (pI) was between 5.5 and 6.5. These results suggest that FF101 synthesizes a novel growth factor which has little specificity in both species and organs.

Animals↗
PubMed1989

Cloning of serum RNA associated with hepatitis C infection suggesting heterogeneity of the agent(s) responsible for the infection.

Fifty-six lambda gt11-random-primed-cDNA recombinants of which translation products react with antibodies in the serum drawn from patients with hepatitis C (blood-borne non-A, non-B hepatitis) were cloned from serum pooled from donors presumably infected with hepatitis C. The specificity of these clones for hepatitis C infection was determined using 3 test panels. Of these 29 clones were determined to be specific for Japanese hepatitis C infection. However one of the 29 clones was positive for 1 out of 5 normals in an American test panel while 12 clones were positive for the American panel as well. The remaining 28 clones reacted well with serum from transfusion associated chronic hepatitis C comparing to the sporadic cases in the Japanese panel. When they were tested with normal donors, another clone reacted with a distinct donor group with which the other clones did not react. These results may suggest the presence of heterogeneity in Japanese hepatitis C.

Cloning, Molecular↗
PubMed1989

A new microphotometric method for measurement of cytochrome P-450 in sections of liver.

We developed a new microphotometric method for measuring the amounts of cytochrome P-450 (P-450) in fresh frozen sections of liver. Four serial frozen sections cut from the liver were separately incubated in 50 mM Tris-HCl buffer (pH 8.0) alone, in buffer containing sodium dithionite, in buffer saturated with carbon monoxide (CO), and in buffer saturated with CO and containing sodium dithionite. The difference between absorbance at 450 nm and that at 490 nm was measured in these sections with a simple microphotometer system. This method yielded precise amounts of P-450 in sections by measuring the true extinction of P-450 and by minimizing the effect of contaminating hemoproteins. Livers of adult rats contained large amounts of P-450, which was greater in perivenular hepatocytes than in periportal hepatocytes. In livers of newborn rats, however, small amounts of the enzyme were distributed evenly throughout the lobule.

Aging↗
PubMed1989

High activity of acid phosphatase of Pseudomonas pseudomallei as a possible attribute relating to its pathogenicity.

Phosphatase activities were compared quantitatively among selected species of pseudomonads. P. pseudomallei showed the highest activity of a bell-shaped pH pattern with a peak at around pH 5.0. P. cepacia had a similar pattern of milder intensity. In contrast, P. aeruginosa revealed an alkaline phosphatase activity with a pH optimum higher than 8.0, but the level of activity was much lower than those of the above two species. The enzymatic reactions of other species were slight or negligible at their optimum pH in the same test system. These data were discussed in reference to their growth behavior in different pH environments and also in connection with such recent information that the high activity of microbial acid phosphatase may be a favorable attribute to their intracellular parasitism.

Acid Phosphatase↗
PubMed1989

[Pathologic response of the retinal pigment epithelium. The effect of mucopolysaccharide in the subretinal space to phagocytosis. Part 5].

Previously we reported that retinal pigment epithelial cells (RPE) showed different phagocytotic activity according to the charge characteristics of the surface of polystyrene particles which were injected into the subretinal space of albino rats. In this study we examined whether subretinal mucopolysaccharide controls RPE phagocytosis or not, using positive or negative charged particles (3 microns in diameter). The technique of ruthenium red staining, a cationic dye, was employed with special efforts to detect the relationship between acid mucopolysaccharide and particles at the electron microscopic level. Six hours after injection of the positive charged particles, the ruthenium red staining revealed fine granular electron-dense materials, coating the surfaces of many small substances surrounding polystyrene particles which were not yet phagocytized by RPE. On the other hand, there was no staining of negative ones which were already phagocytized by RPE. At 24 hours, no staining was observed on the surface of either particles. These findings suggest that an anionic property of mucopolysaccharide in the subretinal space controls the phagocytosis of RPE.

Animals↗
PubMed1989

[Non-granulomatous anterior uveitis and HLA-B27 antigen].

In Caucasians, there is close correlation between acute anterior uveitis and histocompatibility antigen HLA-B27. But in Japanese, this is not clear. Therefore, we examined 58 patients with non-granulomatous anterior uveitis (NGAU) about HLA typing in our uveitis clinic at Tokyo Women's Medical College Hospital. HLA-B27 was identified in 20 out of 58 patients (34.5%) with NGAU and it was statistically significant. We also studied the clinical features of patients with HLA-B27 positive NGAU. We found that in HLA-B27-positive NGAU, the visual acuity was more strongly affected during the attack and the duration of inflammation was longer than HLA-B27 negative NGAU patients. The duration of the first attack was longer than re-attack, and the duration of the first attack was longer than HLA-B27 negative NGAU patients. It was less commonly associated with systemic disorders in Japanese HLA-B27 positive anterior uveitis than in Caucasian. However, in Japanese NGAU patients without systemic disorders, there was the same tendency concerning the HLA-B27 positive rate as in Caucasians.

Asian People↗
PubMed1989

[Pathologic response of the weak damaged retinal pigment epithelium (RPE)--affected by sodium iodate (NaIO3)].

We examined the cellular responses of the retinal pigment epithelium (RPE) damaged by sodium iodate. RPE was damaged by intravenous administration of sodium iodate, 10mg per kg body weight, in rats. This dose of the agent damaged RPE weakly. Twenty-four hours after the administration of sodium iodate, polystyrene particles were injected into the subretinal space trans-sclerally. Rats were sacrificed at 6 hours to 4 days after injection of particles. Twenty four hours after injection of sodium iodate, RPE were weakly damaged. The cell organelles were swollen and ruptured, but cell structures were not destroyed. Then particles were injected into the subretinal space, RPE did not phagocytize the particles until 24 hours after the injection of particles. After 48 hours, RPE showed proliferation. After 4 days, RPE formed thick multilayers in the subretinal space and transformed to spindle shapes, and RPE underwent metaplasia to fibroblast-like cells. However proliferation of RPE was not marked. RPE cells weakly damaged by sodium iodate showed delay in phagocytosis of the particles and decrease in proliferation and metaplasia to fibroblast-like cells.

Animals↗
PubMed1989

[Pathologic response of the regenerated retinal pigment epithelium (RPE)--affected by sodium iodate (NaIO3)].

Phagocytosis, proliferation and metaplasia to fibroblast-like cells in the regenerated retinal pigment epithelial cell (RPE) were examined after damage caused by administration of sodium iodate. The solution of sodium iodate (40 mg/kg) was given in a single intravenous injection in rats. Three days after injection, RPE showed marked necrotic damage, but in 2 weeks flat regenerated RPE with short microvilli and no basal infolding were seen on Bruch's membrane. Polystyrene particles were then injected into the subretinal space. The rats were sacrificed 6 hours to 4 days after injection of the particles. The regenerated RPE showed phagocytosis within 6 hours. After 48 hours, they showed multilayer proliferation. After 4 days RPE transformed to spindle-shaped fibroblast-like cells. However proliferation and metaplasia of RPE markedly decreased. The results showed significant decrease in the function of regenerated RPE-cells as a result of their damage.

Animals↗
PubMed1988

Expression of a hepatocyte membrane antigen during hepatocarcinogenesis and in the developing liver of the rat.

Changes in the expression of a cell membrane antigen during hepatocarcinogenesis and in the developing liver were analyzed by HAM.4, a monoclonal antibody (MAb) against a membrane glycoprotein of normal rat hepatocyte. Of the precancerous lesions observed during hepatocarcinogenesis induced by diethylnitrosamine, 2-acetylaminofluorene and partial hepatectomy, early neoplastic foci were uniformly stained by HAM.4. In contrast, some cells in the neoplastic nodules at the late stage did not express HAM.4 antigen on the cell surface. Of the cancer tissues, well-differentiated hepatocellular carcinomas were stained by HAM.4 whereas poorly differentiated carcinomas did not bind HAM.4 In developing rat liver, HAM.4 antigen was first expressed on fetal hepatocytes at the 18th day of gestation. It gradually increased until 4 weeks after birth when the intensity of the stain was almost the same as in adult rat liver. These results suggest that the expression of a membrane antigen defined by HAM.4 is closely associated with the differentiation of bile canalicular face and that HAM.4 might be useful in characterizing differentiation of cells during malignant transformation of hepatocytes.

Animals↗
PubMed1988

Morphological differences between secretory cells of wet and dry types of human ceruminous glands.

Morphological differences between secretory cells of the wet and dry types of human ceruminous glands were examined. The heights of secretory cells varied from tall and medium to low in both wet- and dry-type glands. The two gland types differed in morphologic features of the tall cells and the cells of medium height. The Golgi apparatus was well developed in the tall cells and fairly well developed in the cells of medium height in the wet-type gland, whereas it was generally small in the corresponding cells of the dry type. Light granules were abundant in the tall cells and in the cells of medium height in the wet-type gland, whereas light granules were rare in these cells in the dry-type gland. Furthermore, the light granules in the wet-type gland cells were observed in close relation to a well-developed Golgi apparatus, and sometimes showed a morphologic appearance suggesting exocytosis. Apical protrusions, probably related to apocrine secretion, were generally large and round and bore "microvilli and light granules" or "very few microvilli and no light granules" in the tall cells of the wet-type gland. However, the protrusions of the tall cells of the dry-type gland were generally large and slender and possessed no microvilli and no granules. The protrusions were not observed in the cells of medium height or in low cells in either type of gland. The results show that eccrine secretion characterizes the wet-type gland, but it is not clearly evident in the dry-type gland. This differences may be related to differences in composition between the wet and dry cerumens.

Adult↗
PubMed1988

High glucose-6-phosphatase activity in osteoblasts in the metaphysis of femur of growing rats.

Glucose-6-phosphatase (G6Pase) activity was examined cytochemically in the metaphysis of femurs of 3- and 7-day-old rats. G6Pase and hexokinase activities were also examined biochemically in the femur and tibia of 3-day-old animals. The reaction product for G6Pase activity was seen in the endoplasmic reticulum and nuclear envelope of all cell types composing the metaphysis. The amount of the reaction product was abundant in osteoblasts, moderate in osteocytes, and moderate to scarce in osteoclasts and capillary endothelial cells. Biochemical G6Pase activity in the bones was higher than that in the brain, submandibular gland, or pancreas of the animals. Hexokinase activity in the bones was not different from that in the submandibular gland, pancreas, or kidney. The activity ratio of G6Pase and hexokinase in the bones (0.603) was greater than that in the submandibular gland, pancreas, or brain and smaller than that in the kidney. Possible physiological significances of the higher G6Pase activity in osteoblasts are discussed.

Animals↗
PubMed1988

Antithrombin III concentrate in the treatment of fulminant hepatic failure.

Twenty-six patients with fulminant hepatic failure were treated with daily infusions of antithrombin III concentrate until recovery of consciousness or death. Seven patients were alive (group A), 7 survived 17 to 47 days after treatment (group B), and 12 died within 9 days (group C). Decreased plasma antithrombin III levels increased on the day after treatment, irrespective of the pretreatment levels in all patients. Continuous or temporary normalization was seen in all patients in groups A and B, but in only 5 in group C patients whose bleeding was extensive (p less than 0.05). An abrupt drop in peripheral platelet counts occurred when plasma antithrombin III levels were below normal. General bleeding accompanied this drop. These results suggest that maintained normal plasma antithrombin III levels are beneficial for prolonged survival time in fulminant hepatic failure, probably through controlling intravascular coagulation, and that antithrombin III infusion may be useful for such treatment.

Antithrombin III↗