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Biomedical subjects

F Kondo

Publications and source records attributed to F Kondo.

At least 19 recordsLinked to original sources
PubMed2002

Bisphenol a degradation by bacteria isolated from river water.

Recently, there is increasing interest in the microbial degradation of endocrine disruptors. This study was conducted to show the isolation and property of bacteria having bisphenol A (BPA) biodegradability in river water and to identify the difference of BPA degradation under aerobic and anaerobic conditions. Three river water samples spiked with BPA (1 mg/L) were rapidly degraded under aerobic conditions. The half-life for BPA degradation ranged from 2 to 3 days, and BPA was below detection limit (less than 0.005 mg/L) on the 10th day. But a decrease of BPA under anaerobic conditions was hardly identified at 30 degrees C for 10 days (less than 10%). Also, most bacteria (10 out of 11) isolated from three river waters had BPA biodegradability, but there were differences in removal rates of BPA (18% to 91%). Moreover, two strains that had high BPA biodegradability (about 90%) were identified as a Pseudomonas sp. and a Pseudomonas putida strain.

Benzhydryl Compounds↗
PubMed2002

Development of a combined filtration-enrichment culture followed by a one-step duplex PCR technique for the rapid detection of Campylobacter jejuni and C. coli in human faecal samples.

A new combined filtration-enrichment culture followed by a PCR technique for the rapid detection of Campylobacterjejuni and C. coli in human faeces has been developed. Only bacteria that passed through the membrane could multiply in the enrichment culture; target bacteria were detected by a one-step duplex PCR technique with combinations of primers that are specific for different Campylobacter spp., which should allow for the detection of a mixed infection in a single patient. A Falcon cell-culture insert and 24-well tissue-culture plates were used. After 2 days, both C. jejuni and C. coli were reliably detected in diluted faeces that were seeded with as few as 10 cells which corresponds to a concentration of 10(3) cfu/g. Even allowing for the dilution of faecal samples, this represents an increase in sensitivity of two-to-three orders of magnitude over the conventional filtration method.

Campylobacter coli↗
PubMed2001

Co-production of microcystins and aeruginopeptins by natural cyanobacterial bloom.

The relationship between Microcystis composition and the production of microcystins and nontoxic peptides in bloom cells, which was regularly collected in Lake Suwa, Japan, in the summer season from 1991 to 1994, was investigated. In order to determine the structures of the nontoxic peptides, we collected large amounts of bloom materials from the same lake on July 23, 1991, and isolated three nontoxic peptides. They were named as aeruginopeptins 917S-A, -B, and -C, and their structures were mainly determined by a mass spectrometry/mass spectrometry (MS/MS) technique as 19-membered cyclic depsipeptides possessing the Ahp (3-amino-6-hydroxy-2-piperidone) moiety. An analysis of the microcystins and aeruginopeptins in the collected blood cells and their Microcystis composition suggested that the M. aeruginosa large cell size produces both microcystins and aeruginopeptins, and the production of both compounds is genetically closely related.

Cell Size↗
PubMed2001

Progressive cortical atrophy after forebrain ischemia in diabetic rats.

The morphological changes in the brain of diabetic rats were examined up to 8 weeks after transient forebrain ischemia produced by transient occlusion of both carotid arteries. Using histochemistry, we also examined the extent and rate of development of atrophic changes in the brain, appearance of astrocytes, activated microglia, and glucose transporter 1 (GLUT1) in streptozotocin-treated rat brains after forebrain ischemia. Atrophic changes appeared in the hippocampus in both non-diabetic-- and diabetic--ischemic groups 4 weeks after ischemia. In diabetic--ischemic rats, the atrophic changes were more severe and progressed more rapidly in the hippocampus, and were also observed in the frontal, temporal and parietal cortices, but not in any cortical areas of the non-diabetic--ischemic rats and non-ischemic--diabetic rats. We observed reduced density of GLUT1 in all cortical regions and hippocampus in ischemic-diabetic rats at 4--8 weeks, when the number of activated microglias and astroglias increased in all cortical regions. Although severe atrophic changes were observed in the gray matter, no serious injury was noted in the white matter in the diabetic-ischemic group. Our results indicate that brain ischemia in the presence of diabetes causes more severe late-onset damage culminating in brain atrophy, compared with non-diabetics.

Animals↗
PubMed2001

Benign nodular hepatocellular lesions caused by abnormal hepatic circulation: etiological analysis and introduction of a new concept.

Problems in definitive diagnosis and etiology of various benign nodular hepatocellular lesions were evaluated. Of these lesions, focal nodular hyperplasia (FNH), nodular regenerative hyperplasia (NRH), nodular lesions associated with idiopathic portal hypertension (IPH), non-cirrhotic large regenerative nodules (LRN), hepatocellular adenoma (HA)-like hyperplastic nodules, and partial nodular transformation (PNT) have been suggested to be related to abnormal hepatic circulation. However, the following points are considered to need further clarification: (i) is the abnormal circulation caused by thrombosis, vasculitis, or congenital anomaly?; (ii) is thrombosis a cause or a result of congestion?; (iii) are impaired blood vessels primarily the portal veins or arteries?; (iv) how are these disorders related to various syndromes, immunological abnormalities and abnormal blood flow of other organs, which are reported to coexist with these lesions often?; and (v) how should non-typical cases, which differ from typical cases, be interpreted? In addition, a concept that may lead to solving these problems (anomalous portal tract syndrome; a hypothesis that congenital vascular anomaly is the origin of these benign nodular hepatocellular lesions) was introduced.

Focal Nodular Hyperplasia↗
PubMed2001

Characterization of hyperplastic foci observed in surgical specimens of hepatocellular carcinoma.

By reviewing previous surgical specimens of hepatocellular carcinoma, 17 cases with hyperplastic foci (HPF) characterized by discernible increase in nuclear densities, could be histologically selected. Nuclear densities of HPF and control hepatic parenchyma were assessed quantitatively by counting the nuclear number of hepatic cells, and proliferating cell nuclear antigen labeling index was measured. HPF occurred multifocally, confined within a lobular unit, smoothly merging into surrounding hepatic parenchyma. Nuclear densities of HPF were 1.71 times greater than those of control hepatic parenchyma. The hepatocytes of HPF also showed significantly higher proliferative activities than those of control parenchyma. In addition, noticeable structural distortions, such as focal trabecular thickening or microacinar formation of hepatocytes, were sometimes observed in HPF. However, these HPF seemed to be distinguished from minute de novo hepatocellular carcinoma (HCC) or intrahepatic HCC metastasis, because of paucity of distinctive atypical changes, and intimate correlation with neighboring hepatocytes. Several adjacent HPF were aggregated to form a much larger unit of a hyperplastic area with loss of fibrous septa of liver cirrhosis. It was suggested that grossly detectable large regenerative nodules are produced via fusion of several adjacent HPF.

Adult↗
PubMed2001

Clinicopathological study of a hilar nodule in the livers of long-term survivors with biliary atresia.

With the application of liver transplantation for patients with biliary atresia (BA), we have had the opportunity to review the clinicopathologic features of the native livers from 10 transplanted BA patients. A single large nodule at porta hepatis (hilar nodule) was noted in three of 10 patients, and an ill-defined nodule-like lesion at porta hepatis was present in two other patients. The three BA patients with hilar nodules were long-term survivors, compared to the patients with nodule-like and those without nodules. The hilar nodules measured between 5.0 cm and 8.0 cm and histologically, they were partly surrounded by fibrous septa with relatively well-preserved liver architectures and fewer inflammatory cells at the portal triads when compared to the surrounding cirrhotic lesions. No nuclear or cellular atypia was observed. Proliferating cell nuclear antigen labeling index was higher in the surrounding cirrhotic lesions than the hilar nodules. The nodule-like lesions at porta hepatis also showed similar light microscopic and immunohistochemical features as the hilar nodules. These hilar nodules did not seem to contain any malignant potential. The benign histology with relatively well-preserved liver architecture and the preferential site of occurrence at porta hepatis where bile seemed to flow more smoothly, suggested possible residues of less-affected hepatic tissues.

Biliary Atresia↗
PubMed2001

Low metacarpal bone density, tooth loss, and periodontal disease in Japanese women.

The relationship between periodontitis and systemic bone mineral density in Japanese women is undetermined. We tested the hypothesis that periodontitis was more frequent in women with low metacarpal bone mineral density (m-BMD). Subjects were 190 Japanese women (89 premenopausal, 101 post-menopausal). Periodontal status was evaluated according to the Community Periodontal Index of Treatment Need (CPITN). M-BMD was measured by computed x-ray densitometry. The proportion of subjects with periodontitis (CPITN > or = 3) increased as m-BMD decreased in pre-menopausal (18.2%, 36.9%, and 66.6% in the normal, borderline, and very low m-BMD groups, p < 0.02) and post-menopausal women (41.5%, 54.8%, 60%, and 68.4% in the normal, borderline, low, and very low m-BMD groups, p < 0.05). Among post-menopausal women, those with very low m-BMD had fewer teeth present than women with normal m-BMD (19.9+/-7.2 vs. 25.1+/-4.1, p < 0.01). These results indicate that m-BMD loss is associated with periodontitis in Japanese women, and with tooth loss after menopause.

Adult↗
PubMed2001

Improved agar diffusion method for detecting residual antimicrobial agents.

The improved agar diffusion method for determination of residual antimicrobial agents was investigated, and the sensitivities of various combinations of test organisms and assay media were determined using 7 organisms, 5 media, and 31 antimicrobial agents. Bacillus stearothermophilus and synthetic assay medium (SAM) showed the greatest sensitivity for screening penicillins (penicillin G and ampicillin). The combination of Bacillus subtilis and minimum medium (MM) was the most sensitive for tetracyclines (oxytetracycline and chlortetracycline), B. stearothermophilus and SAM or Micrococcus luteus and Mueller-Hinton agar (MHA) for detecting tylosin and erythromycin, B. subtilis and MHA for aminoglycosides (streptomycin, kanamycin, gentamicin, and dihydrostreptomycin), B. stearothermophilus and SAM for polyethers (salinomycin and lasalocid), and B. subtilis and MM or Clostridium perfringens and GAM for polypeptides (thiopeptin, enramycin, virginiamycin, and bacitracin). However, gram-negative bacterium Escherichia coli ATCC 27166 and MM were better for screening for colistin and polymixin-B. For detecting the synthetic drugs tested, the best combination was B. subtilis and MM for sulfonamides, E. coli 27166 and MM for quinolones (oxolinic acid and nalidixic acid), B. subtilis and MM for furans (furazolidone), and the bioluminescent bacterium Photobacterium phosphoreum and luminescence assay medium for chloramphenicol and oxolinic acid. The results showed that the use of four assay plates, B. stearothermophilus and SAM, B. subtilis and MM, M. luteus and MHA, and E. coli 27166 and MM, was superior to the currently available techniques for screening for residual antimicrobial agents in edible animal tissues.

Agar↗
PubMed2001

Occurrence of false-positive results of inhibitor on milk samples using the Delvotest SP assay.

Three hundred twenty-one quarter, 207 whole udder, 310 bulk tank, and 93 tank-lorry milk samples were examined for confirmation of the presence of inhibitor by Delvotest SP assay. Four hundred twenty-six Holstein cows of no drug treatment for at least 30 days from January 1998 to September 1999 were used. Reading time was 2.50, 2.75, and 3.00 h, and results of sampling were recorded by four types according to comparison with the color of the well containing the control milk sample. False-positive outcome was identified by Delvotest SP assay in quarter (13 of 321), whole udder (9 of 207), and bulk tank milk samples (4 of 310), but was not shown on tank-lorry milk samples (0 of 93) at the reading time of 2.50 h. All of the 26 false-positive samples were negative from the examination after heat treatment at 82 degrees C for 5 min. But, two bulk tank milk samples that appeared to have positive results in LacTek and Charm II tests were positive from the test following heat treatment. Somatic cell counts (SCC) were related to the probability of a false-positive result. The more SCC increased, the more the occurrence of a false-positive result increased. In our investigations, 4 of 310 bulk tank milk samples at the reading time of 2.50 h produced false-positive results, and no false-positive results were apparent at a reading time of 2.75 h. Also, the occurrence of false-positive results in quarter and whole udder milk samples decreased when agar was cultured for 2.75 to 3.00 h. There were no false-positive results from tank-lorry milk samples. These results indicate that the Delvotest SP assay may provide a suitable means for the detection of drug residues in not only quarter and whole udder milk of cows but also in bulk tank and tank-lorry milk following reading times of 2.75 to 3.00 h.

Animals↗
PubMed2001

A simple classification method for residual antibiotics using E. coli cells transformed by the calcium chloride method and drug resistance plasmid DNA.

Using three different plasmid DNA codings for kanamycin (KM), chloramphenicol (CP), and ampicillin- (AMP) and tetracycline- (TC) resistance, four different competent Escherichia coli strains were transformed by the calcium chloride method to produce KM-, CP- and AMP- and TC-resistant strains. Evaluation of minimum inhibitory concentrations (MIC) of 22 antibiotics, showed KM-resistant E. coli to be cross resistant only to fradiomycin (FRM); CP-resistant E. coli, especially HB101 and JM109 strains, exhibited cross-resistance only to thiamphenicol (TP). On the other hand, AMP- and TC-resistant E. coli showed cross resistance to several penicillins, tetracyclines and erythromycin. E. coli ATCC-27166, the strain most sensitive to all drugs in this experiment, was employed for disc diffusion experiments and from the pattern of appearance of the inhibition zone, eight major antibiotics were divided into three groups depending on their activity against containing each of the three plasmids. Only gentamicin (GM) activity was not affected by any of the drug resistant strains. Assay techniques utilizing three resistant strains may be the technique for screening foods for antibiotic residues in the future.

Aminoglycosides↗
PubMed2001

The effects of subminimal inhibitory concentrations of beta-lactam antibiotics against Clostridium perfringens.

The effects of subminimal inhibitory concentrations (sub-MIC) of four beta-lactam antibiotics [penicillin-G (PCG), ampicillin (AMP), cephaloridine (CER), cephalothin (CET)] were tested against Clostridium perfringens type A PB6K, after determining the minimum inhibitory concentrations (MIC) of 29 different Clostridium strains. The majority of the strains were sensitive to all beta-lactam antibiotics. Morphological changes, such as filamentous development and lysis, occurred at concentrations considerably lower than the MIC of CER and CET in C. perfringens. Clear cooperation of AMP and CER with rabbit polymorphonuclear leucocytes (PMNL) against C. perfringens was observed. The filamentous bacteria produced as a result of exposure to sub-MIC of each antibiotic, were phagocytosed easily. The ratios between the drug concentrations (microg/ml) at which the morphological changes began to occur, the minimum antibiotic concentrations (MAC), and the MIC values (microg/ml), were calculated. A large ratio indicated a wide range of effective concentrations below the MIC value for the antibiotics.

Animals↗
PubMed2001

DNA diversity of the wla gene cluster among serotype HS:19 and non-HS:19 Campylobacter jejuni strains.

Campylobacter jejuni infection is an important trigger of Guillain-Barré syndrome (GBS), and serotype HS:19 strains are over-represented among GBS-associated isolates. Structures in C. jejuni lipooligosaccharide (LOS) resemble human gangliosides, suggesting that molecular mimicry could be important in triggering the neural injury. We assessed the genetic diversity among 36 C. jejuni serotype HS:19 and non-HS:19 strains by analysis of PCR-based restriction fragment length polymorphism (RFLP) patterns of 12 LOS biosynthesis-related genes (wla cluster). PCR amplification revealed that the size, order, and direction of each wla gene was identical among all strains tested. However, an additional ORF, located between wlaI and wlaK, was detected in 28 of the 36 isolates examined, and nucleotide sequence analysis revealed that the gene was identical to orfE in C. jejuni strain NCTC 11168. An inverted repeat motif was found downstream of the wlaI stop codon and upstream of the orfE stop codon, an organization allowing pairing of repeated sequences that could lead to deletion of the internal segment. Digestion of the PCR products with restriction endonuclease DdeI or AluI and cluster analysis of RFLP banding patterns showed that all HS:19 strains were closely related and distinct from non-HS:19 strains, consistent with earlier analyses, suggesting that HS:19 strains represent a highly clonal population. RFLP analysis of wla genes also may be useful for epidemiological studies.

Base Sequence↗
PubMed2000

Delayed neuronal death in hippocampal CA1 pyramidal neurons after forebrain ischemia in hyperglycemic gerbils: amelioration by indomethacin.

Hyperglycemia worsens ischemic-induced neuronal damage. Many reports argue the delayed neuronal cell death (DND) after forebrain ischemia in gerbils is due to apoptosis. We examined the effects of hyperglycemia and indomethacin on DND after forebrain ischemia in gerbils. Complete occlusion of both common carotid arteries was performed for 3.5 min followed by declamping and reperfusion. Blood glucose levels were maintained at 25-30 mmol/1 for 24 h after reperfusion in the hyperglycemic groups. We examined morphological changes consistent with DND using Nissel-stained sections and DNA fragmentation using TUNEL staining, at 12, 24, 36, 48, 60, 72, 84, 96, 108, 120 h, and 7 days after reperfusion. DND was noted 96-120 h after ischemia in normoglycemic group. Hyperglycemia enhanced the development of DND at an earlier stage (48-84 h after ischemia). TUNEL positive neurons were detected 72-108 h after reperfusion in normoglycemic group, but very few TUNEL positive neurons were detected in hyperglycemic group at 36-48 h. Indomethacin reduced the number of TUNEL-positive cells in normoglycemia and completely inhibited the appearance of TUNEL-positive cells under hyperglycemia. The number of viable neurons at 7 days after ischemia was markedly higher in indomethacin-treated groups than vehicle-treated group. Our results indicate that hyperglycemia worsens DND after forebrain ischemia in gerbils but such process is not associated with DNA fragmentation. Our results also showed that indomethacin provides a neuroprotective effect in normo- and hyperglycemic conditions.

Animals↗
PubMed2000

First report on the distribution of orally administered microcystin-LR in mouse tissue using an immunostaining method.

The purpose of this study was to investigate the distribution of microcystin-LR (MCLR) orally administered to mice using an immunostaining method. MCLR was orally dosed at 500 microg/kg to aged Balb/C and ICR mice and their lethality was 23.9%. The former was more sensitive to MCLR than the latter, suggesting that oral toxicity by MCLR is related to the animal strains tested, although the pathological and immunostaining changes were essentially the same in both strains. According to this method the distribution of MCLR and related compounds were indicated as the red staining. Particularly, livers of dead aged mice were intensively stained. The main route of absorption was considered to be the small intestine because the villi contained a large amount of MCLR in both surface epithelial cells and lamina propria, resulting in erosion. The absorbed MCLR was contained in blood plasma and moved to the liver, lung, and heart, and finally to capillaries of the whole body. Excretion of MCLR was shown in the mucous from goblet cells in both the small intestine and large intestine.

Animals↗
PubMed2000

Immunoaffinity purification method for detection and quantification of microcystins in lake water.

We have developed a new clean-up method, which consisted of solid-phase extraction on a Sep-Pak PS-2 (styrene-divinylbenzene copolymer) or Excelpak SPE-GLF (polymethacrylate) cartridge instead of conventional ODS silica gel and silica gel together with following immunoaffinity purification using anti-microcystin-LR monoclonal antibodies. This newly developed method was demonstrated to eliminate co-existing substances and to concentrate microcystins in the lake water. The recoveries from lake water (1 liter) spiked with 100 ng each of microcystins-RR, -YR and -LR were 85.5, 89.2 and 92.2%, respectively, with coefficients of variation of 3.3-7.6%. Only 3 h were required to complete the total procedures starting from the microcystin extraction, the immunoaffinity purification, and the quantification using HPLC. The detection limits for all of the 3 microcystins in lake water were 0.005 microg/l. Applicability of this method has been demonstrated by measuring the concentrations of microcystins in water samples collected from lakes where water blooms occurred, which turned out to be 0.012-0.177 microg/l of total microcystins.

Antibodies, Monoclonal↗