Biomedical subjects

M Fukuyama

Publications and source records attributed to M Fukuyama.

At least 19 recordsLinked to original sources

PubMed2007

Genogrouping of vaccine breakdown strains (VBS) of feline calicivirus in Japan.

Although prevention of feline calcivirus (FCV) infection by vaccination has been attempted, and isolation of FCV, development of the disease, and a few fatal cases in vaccinated cats have been reported. Fifteen FCV strains isolated from cats that had been vaccinated with commercially available FCV vaccines (F9, FCV-255, and FC-7) were genogrouped. Molecular analysis of viral genomes involved the construction of a phylogenetic tree of capsid genes using the NJ method. Cat anti-F9 serum and rabbit anti-FCV-255 serum were used for virus neutralization tests. Molecular phylogenetic analysis of the amino acid sequences of 15 virus isolates and those of the previously published and GenBank-deposited 9 global and 14 Japanese strains showed that 8 (53%) of the 15 virus isolates as well as the vaccine strains F9 and FCV-255 belonged to genogroup I (G(A)I), and 7 (47%) belonged to genogroup II (G(A)II). Of the 8 G(A)I strains, 2 were isolated from cats that had been vaccinated with an F9 strain live vaccine, 5 from cats vaccinated with an FCV-255-derived vaccine, and 1 from a cat vaccinated with an FC-7-derived vaccine. Of the 7 GAll strains, 5 were isolated from cats that had been vaccinated with the F9 strain live vaccine, 1 from a cat vaccinated with the FCV-255-derived vaccine, and 1 from a cat vaccinated with the FC-7-derived vaccine. These results indicate that more vaccine breakdown strains isolated from the cats vaccinated with the F9 strain-derived vaccine belong to G(A)II than to G(A)I, whereas more vaccine breakdown strains isolated from the cats vaccinated with the FCV-255 strain-derived vaccine belong to G(A)I than to G(A)II, and that when the FC-7 strain-derived vaccine is used, the vaccine breakdown strains belong almost equally to G(A)I and G(A)II. Thus, the genogroups of virus isolates varied with the vaccine strain used (p < 0.05). On the other hand, the neutralizing titres of feline anti-F9 serum and rabbit anti-FCV-255 serum against the 15 isolates were very low, showing no relationships between neutralizing antibody titres and genogroups. The DNA sequence identities between the virus isolates and the vaccine strains were low, at 70.6-82.9%, and no strains were found to have sequences derived from the vaccine strains. Alignment of amino acid sequences showed that the G(A)I or G(A)II virus isolates from the F9-vaccinated cats differed at position 428 of the 5' hypervariable region (HVR) of capsid region of the F9 strain, whereas those from the FCV-255-vaccinated cats differed at positions 438, 453, and 460 of the 5'HVR of capsid region E of the F9 strain. We speculate that these differences influence genogrouping. The amino acid changes within the F9 linear epitopes common to G(A)I and G(A)II were noted at positions 450, 451, 457 of 5'HVR of the capsid region E in the isolates from F9-derived vaccine-treated cats, and 449, 450, and 451 of 5'HVR of capsid region E in the isolates from FCV-255-derived vaccine-treated cats, suggesting that these amino acid changes are involved in escapes. These results suggest that alternate vaccination with the F9 and FCV-255 strains or the use of a polyvalent vaccine containing GAll strains serves to inhibit development.

Animals↗

PubMed2006

Detection of feline calicivirus (FCV) from vaccinated cats and phylogenetic analysis of its capsid genes.

We analysed genogroups of four feline calcivirus (FCV) isolates (FCV-S, H10, Ao198-1 and ML89) obtained from cats that experienced FCV infection after having been vaccinated against FCV. New PCR primer sets (8F/8R, Ao-S/Ao-A, cp-S/cp-A) were also designed, since the conventional Seal primer failed to amplify the target sequences in two samples. The genogroups of the four isolates as well as eight global and 17 domestic strains were determined by phylogenetic analysis of their amino acid sequences. One out of the four strains (25%) isolated in this study, H10, was grouped into genogroup I, along with the vaccine strains F9 and FCV-255. The other three isolates (75%) belonged to genogroup II. Thus, there were more isolates in genogroup II than in genogroup I. However, the antibody values of the four isolates against cat anti-F9 antisera were significantly decreased. There may be no relationship between the neutralizing antibody titre and genogroup. Amino acid sequence alignment of the four isolates showed that only a single amino acid in region C, which is involved in neutralization epitopes, was different in ML89 strain from that of F9. The other three strains, H10, Ao198-1 and FCV-B, shared the same amino acid sequence with F9. Alignment of amino acids for linear epitopes in the F9 strain, which are located at regions D and E, showed variations in 5' hypervariable region (HVR) of E, whereas D and conE had only synonymous substitutions i.e. no change in the amino acid sequence. This mutation in 5' HVR of region E suggested a vaccine breakdown, as the region is known to be essential for antigenicity. The genogroup II FCV is likely to be the cause of the FCV infection in this study, while the vaccine strains belong to genogroup I. Thus, the existing vaccine may need reevaluation for its effectiveness.

Amino Acid Sequence↗

PubMed2005

Capsid protein genetic analysis and viral spread to the spinal cord in cats experimentally infected with feline calicivirus (FCV).

We investigated primitively the molecular basis of the neural spread of a feline calcivirus isolate (FCV-S) from the spinal cord of a cat that died after manifesting excitation. Experimental infections of cats with three clones from parent virus isolate FCV-S, isolated based on plaque size, were performed, and virus recovery from the spinal cord and the nucleotide and predicted amino acid sequences of the viral capsid protein region (ORF2) were compared. In the experimental infection with the one-time cloned virus (C1L1) isolated from a large plaque, the C1L1 was recovered from the spinal cord. In contrast, seven-times cloned C6L7 (from large plaque) and five-times cloned C5S2 (isolated from small plaque) were not recovered from the spinal cord. Genetic analysis of the capsid protein gene of the three viral clones revealed that four bases were different and two amino acids were different at positions 34 (Val in C6L7 and Ala in C1L1 and C5S2) and 46 (Leu in C6L7 and Pro in C1L1 and C5S2) between C6L7 (with large plaque) and C5S2 (with small plaque). The amino acid at position 434 of C1L1 was different from those of C6L7 and C5S2 (Gly in C1L1, D (Asp) in C6L7 and C5S2). From these results, the plaque size seemed not to be related to the spread of virus to the spinal cord. Clone C1L1, which spread to the spinal cord, had a difference of one amino acid from the other two clones, which may be related to the ability to spread to the spinal cord.

Amino Acid Sequence↗

PubMed2002

Phylogenetic analysis of field isolates of feline calcivirus (FCV) in Japan by sequencing part of its capsid gene.

The molecular epidemiology of the infectious disease caused by feline calcivirus (FCV) in Japan was investigated by analysing the phylogenetic relationship among 21 Japanese field isolates, including the F4 strain, and 30 global isolates. Parts of the capsid gene (B-F) of the isolates were amplified by RT-PCR, and the amino acid sequences were compared with those from the global isolates. Thirty-seven and 14 out of a total of 51 isolates were clustered into two distinct genogroups, I and II respectively, by UPGMA and NJ analysis. Seven of the 21 Japanese isolates (33%) fell into group I together with 30 global isolates, while the other 14 Japanese isolates (67%) belonged to group II. The bootstrap repetition analysis of groups I and II formed by the NJ method gave a value of 99.00%. The 14 latter Japanese isolates were clearly separated from the isolates in group I, and they were different from any previously known FCV, forming a new genogroup, which implies that this lineage has been confined to Japan. Comparing the amino acid sequences shared by groups I and II, the amino acid at position 377 in B region was asparagine (Asn or Asp (NH2)) in group I, while it was lysine (Lys) in all the strains in group II. Similarly, the amino acid at position 539 in the F region was alanine (Ala) or proline (Pro) in group I, while it was valine (Val) in group II; glycine (Gly) at position 557 in group I was serine (Ser) in Group II; and phenylalanine (Phe) or leucine (Leu) at position 566 in genogroup I was tyrosine (Tyr) in group II.

Amino Acid Sequence↗

PubMed2001

Passive immunization with milk produced from an immunized cow prevents oral recolonization by Streptococcus mutans.

Cell surface protein antigen (PAc) and water-insoluble glucan-synthesizing enzyme (GTF-I) produced by cariogenic Streptococcus mutans are two major factors implicated in the colonization of the human oral cavity by this bacterium. We examined the effect of bovine milk, produced after immunization with a fusion protein of functional domains of these proteins, on the recolonization of S. mutans. To prepare immune milk, a pregnant Holstein cow was immunized with the fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region (PAcA) of PAc and the glucan-binding (GB) domain of GTF-I. After eight adult subjects received cetylpyridinium chloride (CPC) treatment, one subgroup (n = 4) rinsed their mouths with immune milk and a control group (n = 4) rinsed with nonimmune milk. S. mutans levels in saliva and dental plaque decreased after CPC treatment in both groups. Mouth rinsing with immune milk significantly inhibited recolonization of S. mutans in saliva and plaque. On the other hand, the numbers of S. mutans cells in saliva and plaque in the control group increased immediately after the CPC treatment and surpassed the baseline level 42 and 28 days, respectively, after the CPC treatment. The ratios of S. mutans to total streptococci in saliva and plaque in the group that received immune milk were lower than those in the control group. These results suggest that milk produced from immunized cow may be useful for controlling S. mutans in the human oral cavity.

Adult↗

PubMed2000

Sensitive enzyme-linked immunosorbent assays for the detection of bacterial superantigens and antibodies against them in human plasma.

Enzyme-linked immunosorbent assays for the quantitation of bacterial superantigens, staphylococcal enterotoxins A, B and C, toxic-shock syndrome toxin-1 and streptococcal pyrogenic exotoxin A, were developed. The assays had sensitivity to quantitate these toxins to 1.4, 5.9, 16.3, 2.5 and 4.3 pg/ml, respectively, in a buffer including 50% human plasma. It takes only 150 min to complete the assays after plate preparation. Specificity of the assays agreed with those of reverse latex agglutination assay. We also developed enzyme-linked immunosorbent assays to detect antibodies against these five superantigens. The assays are expected to be significant tools for the study of superantigens in several diseases.

Animals↗

PubMed2000

[Drug sensitivity, conjugative R plasmids and plasmid profiles of Salmonella isolated from humans with infectious enteritis].

Using 92 Salmonella strains isolated from patients suspected of having infectious diseases of the intestinal tract who visited 13 hospitals in Japan during the six years between 1991 and 1996, we investigated the drug susceptibility, prevalence of conjugative R plasmid, and the plasmid profiles. 1) Of the bacterial isolates tested, 52.2% showed drug-resistance. Regarding the drug-resistance patterns, 70.8% of the isolates were resistant to a single drug, while 29.2% were multi drug-resistant. 2) Dividing the resistance patterns by the serotypes, among Salmonella Enteritidis isolates, single-drug resistance to SM was the most frequent, being detected in 27 isolates. Single-drug resistance to NA and two-drug resistance to SM/TC were the second-most frequent, each being detected in isolates. Among Salmonella Hadar isolates, four isolates showed two-drug resistance to SM/TC, and one isolate showed single-drug resistance to TC. Among Salmonella Typhimurium isolates, one isolate each showed three-drug resistance to ABPC/CER/KM and KM/TC/CP. Among Salmonella Agona isolates, one isolate each showed two-drug resistance to SM/TC and single-drug resistance to SM. Among Salmonella Derby isolates, two isolates showed single-drug resistance to SM. 3) The prevalence of conjugative R plasmid was investigated in 48 drug-resistant isolates, and six isolates (12.5%) contained the plasmid. 4) The prevalence of the plasmid was investigated in 29 drug-resistant S. Enteritidis isolates, and 22 isolates (75.9%) contained the plasmid. These isolated were classified by the plasmid profiles into types H1 to H7. 5) Regarding the plasmid profiles of the S. Enteritidis isolates, a position corresponding to 60 Kbp was the most frequently detected in 90.5%.

Anti-Bacterial Agents↗

PubMed2000

[Antibacterial activity of fosfomycin against the causative bacteria isolated from bacterial enteritis].

The in vitro antibacterial activities of fosfomycin (FOM) and 3 fluoroquinolones against Salmonella spp., pathogenic Escherichia coli, Campylobacter spp. and Shigella spp. were investigated. The activity upon the environmental condition in the inflammation was compared with standard condition in vitro. On standard condition, the MIC90 of tosfloxacin (TFLX), norfloxacin (NFLX) and levofloxacin (LVFX) against E. coli (77 strains), Shigella spp. (50) and Salmonella spp. (41) were < or = 0.025-0.10, 0.10, and 0.05 microgram/ml, respectively. The MIC90 of FOM against those organisms was 0.39-1.56 micrograms/ml. The MIC90 of TFLX, NFLX, LVFX against Campylobacter spp. were 6.25, 100 and 3.13 micrograms/ml, respectively. The MIC90 of FOM was 50 micrograms/ml. The activity of FOM was unaffected by pH and in anaerobic condition. On the other hand, the activity of NFLX was decreased in low pH and in anaerobic condition. In the presence of horse blood and addition of Na+, the activities of both agents were unaffected. These results suggested that FOM is equally active with or superior to fluoroquinolone in the intestinal infection treatment.

Anti-Bacterial Agents↗

PubMed1999

Relationship between apparent accomodation and corneal multifocality in pseudophakic eyes.

OBJECTIVE: To investigate whether any association exists between apparent accommodation in pseudophakic eyes and multifocal corneal effects. DESIGN: A prospective observational case series. PARTICIPANTS: A total of 121 eyes of 98 patients who had undergone phacoemulsification and posterior chamber intraocular lens implantation were studied. METHODS: The amount of apparent accommodation was measured using an accommodometer. The degree of corneal multifocality was determined on the corneal topography by measuring the maximum and minimum corneal refractive powers within the pupillary area. Refractive astigmatism, keratometric astigmatism, pupillary diameter, and age were also analyzed. MAIN OUTCOME MEASURES: Apparent accommodation, corneal multifocality, refractive and keratometric astigmatism, pupillary diameter, and age. RESULTS: Multiple regression analysis revealed that corneal multifocality and pupillary diameter had significant positive correlations with apparent accommodation, whereas other explanatory variables showed no relationship with apparent accommodation. CONCLUSION: Multifocal corneal effects contribute to apparent accommodation in pseudophakic eyes.

Accommodation, Ocular↗

PubMed1999

Radial keratotomy to treat myopic refractive error after cataract surgery.

PURPOSE: To assess the predictability and effectiveness of radial keratotomy in patients with myopic refractive error and unacceptable anisometropia after cataract surgery. SETTING: A prospective multicenter study. METHODS: This study comprised 40 eyes of 40 Japanese patients who had had cataract surgery. Radial keratotomy was performed, and the 6 month postoperative data were analyzed. RESULTS: Mean patient age was 71.0 years +/- 7.4 (SD) (range 51 to 84 years) and mean preoperative anisometropia -3.41 +/- 1.69 D (range -1.25 to -7.75 D). The surgery decreased mean anisometropia to -1.01 +/- 0.94 D (P < .000001, Wilcoxon signed-rank test), a mean reduction of 2.22 +/- 1.23 D (range 0.75 to 5.88 D). Postoperative anisometropia ranged from 0.81 to -3.13 D. The surgical effects were overestimated by the nomograms developed for the correction of naturally occurring myopia in the eyes of white patients. Multiple regression analysis revealed that optical zone size and number of incisions were significantly correlated with the amount of myopic correction, and the regression equation (R2 = 0.77) was expressed as follows: Effects = (-1.45 x optical zone size) + (0.24 x incision number) + 7.60. A new nomogram was derived based on this equation. CONCLUSIONS: Radial keratotomy was a safe and efficient procedure to treat myopic refractive error in pseudophakic eyes. Separate nomograms are necessary for white and Asian populations.

Aged↗

PubMed1999

Antimutagenic activity of polymethoxyflavonoids from Citrus aurantium.

The methanol extract from Citrus aurantium showed a suppressive effect on umu gene expression of SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract from C. aurantium was successively re-extracted with hexane, dichloromethane, butanol, and water. A dichloromethane fraction showed a suppressive effect. The suppressive compounds in the dichloromethane fraction were isolated by SiO(2) column chromatography and identified as tetra-O-methylscutellarein (1), sinensetin (2), and nobiletin (3) by EI-MS and (1)H- and (13)C NMR spectroscopy. These compounds suppressed the furylfuramide-induced SOS response in the umu test. Gene expression was suppressed 67%, 45%, and 25% at a concentration of 0.6 micromol/mL, respectively. The ID(50) value (50% inhibition dose) of compound 1 was 0. 19 micromol/mL. These compounds were assayed with other mutagens, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires liver metabolizing enzymes, activated Trp-P-1, and UV irradiation. These compounds showed of all mutagen-induced SOS response in the umu test. In addition, compounds 1-3 exhibited antimutagenic activity in the S. typhimurium TA100 Ames test.

Antimutagenic Agents↗

PubMed1999

Biologically active components against Drosophila melanogaster from Podophyllum hexandrum.

In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, a dichloromethane extract of Podophyllum hexandrum was found to give an insecticidal activity against larvae of Drosophila melanogaster Meigen. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as podophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays for insecticidal activity, 1 showed a LC(50) value of 0.24 micromol/mL diet against larvae of D. melanogaster and a LD(50) value of 22 microg/adult against adults. Acetylpodophyllotoxin (1A), however showed slight insecticidal activity in both assays, indicating that the 4-hydroxyl group was an important function for enhanced activity of 1.

Animals↗

PubMed1999

Bovine milk antibodies against cell surface protein antigen PAc-glucosyltransferase fusion protein suppress cell adhesion and alter glucan synthesis of Streptococcus mutans.

Cell surface protein antigen (PAc) and glucosyltransferases (GTF) produced by Streptococcus mutans are considered major colonization factors of the organism, and the inhibition of these factors is thought to prevent dental caries. In this study, 8-mo-old pregnant Holstein cows were immunized with fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region (PAcA) of PAc with the glucan binding (GB) domain of GTF-I, an enzyme catalyzing the synthesis of water-insoluble glucan from sucrose. High titers of immunoglobulin antibodies specific for the fusion protein were found in normal milk after reimmunization, and they persisted for approximately 3 mo. The immunoglobulin G (IgG) antibodies against PAcA-GB were purified from immunized milk. The antibodies significantly inhibited the adhesion of S. mutans cells to saliva-coated hydroxyapatite beads. IgG antibodies purified from immunized milk also inhibited total glucan synthesis by cell-associated GTF preparation and GTF-I from S. mutans. The immunized milk may be useful as a means of passive immunization for the prevention of dental caries in humans.

Animals↗

PubMed1999

[Study on the verotoxin-producing Escherichia coli--isolation of the bacteria from deer dung].

To identify the source and route of verotoxin-producing Escherichia coli (VTEC) infection in humans, we tried to isolate VTEC from fresh deer dung collected from free-range animals in two parks during the period from August 1997 to January 1998. The results are presented below. 1) VTEC were isolated from 21 of 200 deer dung samples (10.5%), consisting of 15 of 100 samples (15.0%) collected in park A and 6 of 100 samples (6.0%) collected in park B, suggesting that the incidence of VTEC isolation differs depending on location. 2) With respect to typing of verotoxin, the 21 isolated VTEC strains consisted of 10 strains (47.6%) as VT1 producer, 5 strains (23.8%) as VT2 producer, and 6 strains (28.6%) as double producer of both types. 3) With respect to serogroup of the isolated VTEC strains, 2 strains belonged to O128:H2.1 strain each belonged to the O8:H10, O128:H12, and O169:HUT groups. The remaining 16 strains failed to be identified as particular serotypes. Regarding local distribution of the serotype, in park A, 1 strain each belonged to the O128:H2, O8:H10, and O169:HUT groups. The remaining 12 strains did not clearly show particular serotypes. In park B, 2 strains belonged to O128:H2, and 4 strains failed to show particular serotypes. The remaining 1 strains showed autoagglutination. In conclusion, we isolated VTEC strains from deer that showed types of toxin and serogroups identical to those of human VTEC. Therefore, VTEC found in deer dung could well be a source of VTEC-infectious diseases in humans.

Animals↗

PubMed1999

[Prevalence and serotypes of verocytotoxin-producing Escherichia coli (VTEC) isolates from dairy cattle].

To clarify the source of infection and route of transmission of Verocytotoxin-producing Escherichia coli (VTEC) in humans, we collected fresh feces from healthy dairy cattle reared in Hokkaido, Fukushima, Kanagawa and Okinawa prefectures between June 1996 and March 1997, and attempted to isolate VTEC. The results are described below. 1) VTEC was isolated from 68 (27.1%) of 251 fecal samples tested. VTEC was isolated from 14 (28.0%) of 50 in Hokkaido, 13 (26.0%) of 50 in Fukushima, 20 (39.2%) of 51 in Kanagawa and 21 (21.0%) of 100 in Okinawa. There were no difference in the prevalence among the prefectures. 2) Toxin type and serotype of 85 isolates were determined. Thirty-three isolaties (38.8%) were classified into VT1 toxin and VT2 toxin, respectively, and 19 isolates (22.4%) were classified as the strain that produces both VT1 and VT2 toxins. The toxin types of these isolates were divided by serotypes. The VT1-producing isolates were the most frequent among O111:H-. The VT2-producing isolates included O2:H12, O2:H29, O2:H-, O82:H8, O82:HUT, O153:H19, O153:H42 and O153:H-. Among the isolates producing both VT1 and VT2 toxins, O153:H19 was relatively frequent. Based on findings that many bacterial strains coinciding with toxin types and serotypes of human-derived VTEC isolated from dairy cattle, it was suggested that dairy cattle are closely related to VTEC infection in human as a source of infection.

Animals↗

PubMed1999

An enzyme-linked immunosorbent assay using nuclear antigen for detection of feline herpesvirus 1 antibody.

To detect antibody against feline herpesvirus 1 (FHV-1) in the sera of cats, the sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) using nuclear antigen was investigated. The standardized optical density readings (ODs) of the ELISA obtained by the 1-step serum dilution (1:80) method were compared with the serum neutralization test (SNT) results, with a correlation of 0.993, and with the hemagglutination inhibition (HI) test results, with a correlation of 0.851. The ODs for the ELISA titers were obtained using the serial serum dilution method and were compared with the SNT results, with a correlation of 0.933, and with the HI test results, with a correlation of 0.987. In the experimental infection of 4 specific-pathogen-free cats, the results of different serologic tests (SNT and HI) and the ELISA using the serial serum dilution method revealed rapid production of antibodies after inoculation, whereas the ELISA using the one-step serum dilution method indicated that titers increased more slowly. These results indicate that with the present ELISA using nuclear antigen, there are fewer demands on time and labor, making the method convenient for monitoring FHV-1 infection.

Animals↗

PubMed1998

Arcuate keratotomy to treat corneal astigmatism after cataract surgery: a prospective evaluation of predictability and effectiveness.

OBJECTIVE: Although several nomograms are available for the incisional keratotomy to correct naturally occurring astigmatism, astigmatic keratotomy in eyes after cataract surgery has not been well analyzed. The predictability and effectiveness of arcuate keratotomy in pseudophakic eyes were studied. DESIGN: A prospective, multicenter study. PARTICIPANTS: One hundred four eyes of 86 patients with residual corneal astigmatism of 1.5 diopters (D) or more after cataract surgery were examined. INTERVENTION: Arcuate keratotomy was performed in nine centers by nine surgeons. MAIN OUTCOME MEASURES: The amount of astigmatic correction was calculated using the vector analysis of preoperative and 6-month postoperative refractive cylinder results. RESULTS: Multiple regression analysis showed that optical zone size, number of incisions, and incision length had significant correlations with the amount of astigmatic correction. The regression equation was expressed as effects = (-0.643 x optical zone size) + (0.998 x incision number) + (0.057 x incision length) + 2.356. The parameter of predictability (r2: 35%) was lower than that reported for congenital astigmatism (48 to approximately 56%). A new nomogram was derived based on the multiple regression equation. CONCLUSIONS: Astigmatic keratotomy in pseudophakic eyes is less predictable than that in eyes with idiopathic astigmatism, but the procedure is sufficiently effective in reducing the residual astigmatism after cataract surgery. Individual nomograms are necessary for astigmatic keratotomy in eyes with naturally occurring and postsurgical astigmatism.

Aged↗

PubMed1998

[Mechanism of resistance of Shigella flexneri 2a resistant to new quinolone antibiotics].

A Shigella flexneri 2a strain, which did not respond clinically or in laboratory tests to treatment with new quinolone derivatives, was isolated for the first time in Japan from a patient admitted for diarrhea to a Tokyo hospital. The mechanism of resistance was examined by sequencing the quinolone resistance determining region (QRDR) of the gyrA (a quinolone target enzyme) gene and by comparing the active efflux mechanisms of two strains isolated from this patient (before hospitalization and after tosufloxacin treatment) and one strain isolated from a patient with secondary infection with that of the standard strain ATCC 29903. DNA sequencing revealed that two amino acid substitutions, namely, Ser (TCG)-83-->Leu (TTG) and Asp (GAC)-87-->Gly (GGC), had occurred in the gyrA of all 3 strains isolated from the patients. Examination of the accumulation of antibiotics in these 3 strains revealed that the strain isolated after tosufloxacin treatment had the highest resistance to tosufloxacin, and exhibited decreased accumulation of tosufloxacin in the bacterial cells discharged after 5 days of treatment with this antibiotic. However, accumulation was restored by addition of a proton-pump inhibitor. These results suggest that the strains isolated from the inpatient and the patient with secondary infection acquired resistance due to dual gyrA mutation induced by treatment with new quinolone antibiotics. Furthermore, in addition to this dual mutation, the active efflux mechanism also appears to be associated with resistance in bacteria that have been exposed to tosufloxacin.

Anti-Infective Agents↗