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Biomedical subjects

N Kato

Publications and source records attributed to N Kato.

At least 505 records · Page 28Linked to original sources
PubMed1995

Absorption of nitrogen dioxide and nitric oxide by soda lime.

Inhaled nitric oxide (NO) is used for the treatment of pulmonary hypertension as a selective pulmonary vasodilator. However, NO is oxidized rapidly to the more toxic nitrogen dioxide (NO2). Elimination of NO2 from inspired gas is essential for safe clinical use NO. We therefore investigated the efficacy of soda lime in absorbing NO2 from NO2-containing gases. Commercially available soda limes (Soda sorb and Wako lime-A), were exposed to the following six gas mixtures containing NO and NO2 in a hypoxic carrier gas for 20 min: No. 1: NO 40 ppm; No. 2: NO 35 ppm and NO2 5 ppm; No. 3: NO 30 ppm and NO2 10 ppm; No. 4: NO 20 ppm and NO2 20 ppm; No. 5: NO 10 ppm and NO2 30 ppm; and No. 6: NO2 40 ppm. Both types of soda lime completely absorbed the NO2 in all samples when it was present (Nos 2-6). NO concentration in these gas mixtures was reduced by an amount equal to the NO2 absorbed by soda lime. NO was absorbed minimally when NO2 was not present in the mixture. Nitrite was detected from the Wako lime-A granules exposed to the test gas by the chemical analysis. These findings suggest that soda lime completely absorbs NO2 by chemical neutralization, but NO is absorbed as simultaneously absorbed NO2 only where NO and NO2 coexist. Therefore, we conclude that soda lime is useful for NO2 absorption during NO inhalation therapy but NO monitoring from a point distal to the soda lime is required for precise control of inspired NO concentration.

Absorption↗
PubMed1995

Bacteriology of chronic otitis media, chronic sinusitis, and paranasal mucopyocele in Japan.

A bacteriologic study of cases of chronic otitis media, chronic sinusitis, and paranasal mucopyocele diagnosed at Gifu University Hospital was performed between 1989 and 1992. Bacteria were isolated from all of 13 samples of discharge from the ears of patients with chronic otitis media, all of 14 mucosal biopsy specimens from patients with chronic sinusitis, 8 of 10 aspirate samples from patients with chronic sinusitis, and 9 of 15 aspirates samples from patients with mucopyocele. Cultures often yielded polymicrobial growth, with an average of 3.1, 3.8, and 4.2 species per positive specimen from chronic otitis media, chronic sinusitis, and mucopyocele, respectively. The most commonly encountered anaerobes were Peptostreptococcus, Propionibacterium, and Prevotella species; the most common aerobes were Staphylococcus and Streptococcus species. One strain of Prevotella melaninogenica highly resistant to ampicillin and two strains of Peptostreptococcus resistant to cefaclor were found.

Adolescent↗
PubMed1995

Antibiotic susceptibility profiles of Bacteroides fragilis and Bacteroides thetaiotaomicron in Japan from 1990 to 1992.

The antimicrobial susceptibility of clinical isolates of Bacteroides fragilis and Bacteroides thetaiotaomicron collected from December 1990 through November 1992 was determined by the agar dilution technique. Metronidazole, imipenem, and cefoperazone/sulbactam remained highly active against both organisms. Rates of resistance to those agents were 0, 2%, and 0.9% in B. fragilis and 0, 0.9%, and 3% in B. thetaiotaomicron, respectively. Cefoxitin and other cephamycins were active against B. fragilis; rates of resistance to these agents did not tend to increase. With the inclusion of these data, the variation of rates of resistance to several agents was summarized for each year from 1987 to 1992. Rates of resistance to imipenem decreased in 1991 and 1992 among isolates of B. fragilis (2.3% in 1991, 1.8% in 1992) and B. thetaiotaomicron (2.4% in 1991, 0 in 1992). Rates of resistance to cefoxitin in B. thetaiotaomicron varied from 10% to 38% during these 6 years, though the distributional peak of MIC values did not change. The rate of resistance to ofloxacin in B. fragilis increased from 42% in 1989 to 81% in 1992. The rate of resistance to ampicillin in B. thetaiotaomicron was 68% in 1992--approximately 30% lower than before. Mostly, however, the rates of resistance to the antimicrobial agents examined did not change significantly.

Anti-Bacterial Agents↗
PubMed1995

Supplemental dietary cystine elevates kidney metallothionein in rats by a mechanism involving altered zinc metabolism.

Dietary sulfur-containing amino acids influence zinc and copper status. This study was conducted to investigate the relationship between the status of these elements and tissue metallothionein in rats fed diets supplemented with sulfur-containing amino acids. In a series of experiments, a diet containing 100 g casein/kg diet was unsupplemented or supplemented with L-cystine (3-50 g/kg diet) or L-methionine (3 or 30 g/kg diet). Kidney concentrations of zinc and copper in rats fed the diet supplemented with high levels of cystine (25 or 50 g/kg) were significantly higher than those in rats fed the unsupplemented diet. Kidney concentrations of metallothionein and metallothionein mRNA were also significantly higher in rats fed cystine-supplemented diets. There was a correlation (r = 0.838, P < 0.01) between the levels of zinc and metallothionein in kidney of rats fed the diets with different levels of cystine and zinc. However, in the rats fed the diets with different levels of cystine and copper, the correlation was not as strong (r = 0.587, P < 0.01). The changes in kidney metallothionein concentration due to the addition of 3 or 30 g/kg cystine were associated with parallel changes in serum zinc concentration and in apparent absorption of zinc, but not in serum copper concentration or apparent absorption of copper. Addition of 3 or 30 g methionine/kg diet to the diet did not affect kidney concentrations of metallothionein or zinc. These results indicate that supplementation of cystine to the diet can induce kidney metallothionein through a mechanism involving altered zinc metabolism.

Amino Acids, Sulfur↗
PubMed1995

Novel genotypes of hepatitis C virus in Thailand.

We examined 24 C-type hepatitis specimens from Thailand and detected hepatitis C virus (HCV) RNA in all of them by RT-nested PCR for a portion of the HCV 5' non-coding (5' NC) region and a portion of the HCV core region. However, we failed to detect HCV RNA in 11 specimens by RT-nested PCR for a portion in the non-structural protein 5 (NS5) region that has been used commonly for HCV genotyping. We designed a new primer set for a separate portion of the NS5 region. Using this primer set, we succeeded in amplifying this portion in all 24 specimens. Two novel HCV genotypes, tentatively designated HCV-VII and HCV-VIII, were identified by sequencing these amplified regions. Our newly designed primers for RT-nested PCR may be useful for diagnosing infection as well as for genotyping unidentified HCV genomes.

Base Sequence↗
PubMed1995

Cytokine stimulation during Salmonella typhimurium sepsis in Itys mice.

Cytokine production was measured in mice during Salmonella typhimurium sepsis and intoxication. In mice given live S. typhimurium (10 cfu/mouse), by intra-peritoneal injection, serum levels of tumour necrosis factor (TNF)-alpha and interleukin-6 increased steadily from day 1 until day 4. Interferon-gamma levels showed a transient peak on day 3. Interleukin-1-alpha levels were very low. There were high bacterial counts in the livers at day 3 and deaths occurred from day 4 onwards. Intraperitoneal injection of lipopolysaccharide or heat-killed bacteria also induced all of the cytokines, but their time of appearance and levels varied greatly. Cytokine induction by heat-killed bacteria was more marked. Endotoxaemia decreased with time during intoxication and increased during sepsis. Bioactive TNF, as measured by a cytotoxicity assay, was found only in mice given heat-killed bacteria.

Animals↗
PubMed1995

Saphenous vein graft donor site dermatitis in Japan.

Four cases of saphenous vein graft donor site dermatitis are reported from Japan for the first time. The patients were four Japanese men aged from 57 to 69. They noted pruritic eruptions along the lower extremity scar after coronary artery bypass graft surgery using the autogenous saphenous vein. The eruptions appeared mainly on and around the lower end of the venectomy scars from 1.5 to 9 months after graft operations performed at three different hospitals. All four patients showed an objective sensory deficit of the saphenous nerve around the saphenous vein incision scar, although none of them complained of saphenous neuralgia subjectively. Histologically, two patients showed mild epidermal acanthosis, spongiosis, intraepidermal blisters, and perivascular infiltration of lymphocytes and a few eosinophils around dermal blood vessels. The eruption responded well to topical corticosteroids in all cases, although it recurred again in two patients. The entity is characterized by a subacute (belatedly appearing, then slowly disappearing) dermatitis and a mild sensory deficit of the saphenous nerve. Apparently, mild impediment of the saphenous nerve due to an ablational procedure of saphenous venectomy can play a role in causing saphenous vein graft donor site dermatitis.

Aged↗
PubMed1995

Familial lichen nitidus.

I report familial lichen nitidus in a 33-year-old father and his 3-year-old daughter. Histopathology of small papules in both cases revealed typical features of lichen nitidus. Immunohistochemical examination showed UCHL1-positive, L-26-negative lymphocytes and HAM56-positive histiocytes and multinucleated giant cells in the dermal infiltrate in both cases.

Adult↗
PubMed1995

The 24-hour rhythms in plasma growth hormone, prolactin and thyroid stimulating hormone: effect of sleep deprivation.

Twenty-four hour secretory rhythms of growth hormone (GH), prolactin (PRL) and thyroid stimulating hormone (TSH) were investigated in 9 normal adult men by means of serial blood sampling at 30 min intervals. The profiles of pituitary hormones were compared in 6 subjects between in normal nocturnal sleep condition and in delayed sleep condition. Plasma GH was measured with use of highly sensitive enzyme immunoassay (EIA) recently developed. Plasma TSH was also evaluated by highly sensitive time-resolved fluorometric immunoassay (TR-FIA). Time series analysis of plasma GH and PRL was performed by auto- and cross- correlation and spectral analysis. The detection limit of EIA for GH was 0.3 pg/ml and all plasma GH levels were within the detectable range of this EIA. Cross-correlation and spectral analysis suggested the presence of approximately 2-3 h rhythmicity of plasma GH. Plasma PRL appeared to have some 24-hour rhythmicity besides its sleep-dependent component. Sleep deprivation caused marked elevation of plasma TSH during night time. It is suggested that there appears two mechanisms regulating GH secretion: one has a sleep-independent and ultradian rhythm and another has a sleep-dependent rhythm.

Activity Cycles↗
PubMed1995

[Detection of Bacteroides fragilis enterotoxin from extraintestinal clinical isolates of B. fragilis group organisms].

A total of 300 extraintestinal clinical isolates of Bacteroides fragilis group organisms were assayed for enterotoxin using HT29/C1 cells. Of the 179 strains of B. fragilis, 36 (20.0%) were positive for cell culture assay, a positivity which was neutralized by anti-B. fragilis enterotoxin serum; all 36 strains were confirmed to be enterotoxigenic B. fragilis (ETBF). Among B. fragilis isolated from blood, 18 (31%) of 59 strains were ETBF while 18 (15.0%) of 120 strains isolated from non-blood specimens were ETBF (p < 0.05). None of the 121 strains of the B. fragilis group other than B. fragilis were positive for cell culture assay. These results demonstrated that isolation of ETBF from extraintestinal clinical specimens is not uncommon and that B. fragilis enterotoxin, a metalloprotease, may play a role as a pathogenic factor in blood stream infection and sepsis.

Animals↗
PubMed1995

Effect of a bacterial lipopolysaccharide on biliary excretion of a beta-lactam antibiotic, cefoperazone, in rats.

Klebsiella pneumoniae O3 lipopolysaccharide (LPS) has been found to dramatically modify the pharmacokinetics of the beta-lactam antibiotic cefazolin in rats. This study investigated the effect of LPS on the biliary excretion of the beta-lactam antibiotic cefoperazone (CPZ) in rats. CPZ is known to be actively secreted into the bile by a carrier-mediated transport system. LPS (250 micrograms/kg of body weight) was infused for 20 to 30 min 2 h before an intravenous administration of CPZ (20 mg/kg). The pharmacokinetic parameters of CPZ were estimated by a noncompartment model. LPS induced a significant decrease in the systemic clearance (by approximately 50%) and an increase in the mean residence time of CPZ. Significant decreases were also seen in the bile flow rate and in the biliary recovery of unchanged CPZ in the LPS-treated rats. LPS tended to increase the proportion of urinary excretion of CPZ. LPS significantly decreased the biliary clearance (by approximately 55%) and renal clearance (by approximately 35%) of CPZ. However, no changes in the volume of distribution at steady state for CPZ were observed between the treatment groups. Our findings suggest that LPS induces changes in the pharmacokinetics of CPZ as a result of changes occurring in the biliary secretory system.

Animals↗
PubMed1995

Plasmid-mediated dissemination of the metallo-beta-lactamase gene blaIMP among clinically isolated strains of Serratia marcescens.

The distribution of strains producing metallo-beta-lactamase among 105 strains of Serratia marcescens was investigated. All of these strains were isolated in seven general hospitals located in Aichi Prefecture, Japan, from April to May 1993. Southern hybridization analysis suggested that four S. marcescens strains, AK9373, AK9374, AK9385, and AK9391, had a metallo-beta-lactamase genes similar to the blaIMP gene found by our laboratory (E. Osano, Y. Arakawa, R. Wacharotayankun, M. Ohta, T. Horii, H. Ito, F. Yoshimura, and N. Kato, Antimicrob. Agents Chemother. 38:71-78, 1994), and these four strains showed resistance to carbapenems as well as to the other broad-spectrum beta-lactams. In particular, strains AK9373, AK9374, and AK9391 showed an extraordinarily high-level resistance to imipenem (MICs, > or = 64 micrograms/ml), whereas strain AK9385 demonstrated moderate imipenem resistance (MIC, 8 micrograms/ml). The imipenem resistance of AK9373 was transferred to Escherichia coli CSH2 by conjugation with a frequency of 10(-5). The DNA probe of the blaIMP gene hybridized to a large plasmid (approximately 120 kb) transferred into the E. coli transconjugant as well as to the large plasmids harbored by AK9373. On the other hand, although we failed in the conjugational transfer of imipenem resistance from strains AK9374, AK9385, and AK9391 to E. coli CSH2, imipenem resistance was transferred from these strains to E. coli HB101 by transformation. A plasmid (approximately 25 kb) was observed in each transformant which acquired imipenem resistance. The amino acid sequence at the N terminus of the enzyme purified from strain AK9373 was identical to that of the metallo-beta-lactamase IMP-1. In contrast, strains ES9348, AK9386, and AK93101, which were moderately resistant to imipenem (MICs, > or = 4 to < or = 8 micrograms/ml), had no detectable blaIMP gene. As a conclusion, 19% of clinically isolated S. marcescens strains in Aichi Prefecture, Japan, in 1993 were resistant to imipenem (MICs, > or = 2 micrograms/ml), and strains which showed high-level imipenem resistance because of acquisition of a plasmid-mediated blaIMP-like metallo-beta-lactamase gene had already proliferated as nosocomial infections, at least in a general hospital.

Bacterial Outer Membrane Proteins↗
PubMed1995

A novel integron-like element carrying the metallo-beta-lactamase gene blaIMP.

A plasmid-mediated metallo-beta-lactamase gene was cloned from a carbapenem-resistant Serratia marcescens strain, AK9373. The metallo-beta-lactamase gene was identical to the blaIMP, and it was located in the space between an integrase-like gene and an aac(6')-Ib-like gene. The deduced amino acid sequence for the putative integrase gene showed considerable identity (60.9%) to that of the Escherichia coli integrase reported. Sequences similar to the GTTRRRY and an atypical 59-base element containing a 67-bp inverted repeat sequence, which were peculiar to the integrase-dependent recombination, were also conserved in the flanking regions of the blaIMP gene. These findings imply that the metallo-beta-lactamase gene in S. marcescens AK9373 is carried by a novel integron-like element that is mediated by a transferable large plasmid.

Amino Acid Sequence↗
PubMed1995

Distribution and properties of fructosyl amino acid oxidase in fungi.

Fructosyl amino acid oxidase, and enzyme that can be used for the determination of glycated proteins in blood samples from diabetic patients, was used to screen cultures in our microorganism culture collection. Fructosyl amino acid oxidase was found only in the strains of four genera of fungi, Aspergillus, Fusarium, Gibberella, and Penicillium and exhibited different substrate specificities against fructosyl valine and N epsilon-fructosyl N alpha-Z-lysine. A fructosyl valine-specific enzyme from Penicillium janthinellum AKU3413 was monomeric (M(r), 49,000), was most active at 35 degrees C and pH 8.0, and had a covalently bound flavin adenine dinucleotide as a prosthetic group.

Amino Acid Oxidoreductases↗
PubMed1995

Properties of poly(3-hydroxybutyrate) depolymerase from a marine bacterium, Alcaligenes faecalis AE122.

Alcaligenes faecalis AE122 that used poly(3-hydroxybutyrate) (PHB) as a sole source of carbon was newly isolated from a coastal seawater sample. The strain required seawater for growth on PHB as well as in a nutrient broth, in which seawater could be replaced by an appropriate concentration of NaCl. PHB depolymerase was purified to homogeneity from the culture supernatant of A. faecalis AE122 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme consisted of a monomer subunit with a molecular mass of 95.5 kDa. The N-terminal amino acid sequence was GAWQNNLAGGFNKV. The dimeric and trimeric esters of 3-hydroxybutyrate were the main hydrolysis products of the purified enzyme. The enzyme was most active at pH 9.0 and 55 degrees C and was inhibited by phenylmethylsulfonyl fluoride. Several cations in seawater greatly enhanced the enzyme activity.

Alcaligenes↗