Doxorubicin enhances transient expression of p-glycoprotein and modulates activity and isoform expression of protein-kinase-C in ah66 rat hepatoma-cells

Intracellular changes in enzyme activity and the isoform pattern of protein kinase C (PKC) during treatment with doxorubicin (DXR) were examined in a rat ascites hepatoma AH66 parental cell line (AH66P), which shows slight expression of P-glycoprotein (Pgp) on the cell membrane and is classified as an intrinsic multidrug-resistant cell. AH66P cells, treated for 10 days with DXR at the concentrations of 0.3 or 5.0 muM, exhibited moderate to severe inhibition of PKC activity after transient increase of the activity, which mainly was either Ca2+-independent and phospholipid-dependent or Ca2+-independent and phospholipid-independent. PKC isoform analysis of the treated cells also indicated the transient 1.5- and 1.8-fold increase of PKC-delta and PKC-zeta as well as slight increase of PKC-alpha in treatment with 0.3 muM DXR and 1.9- and 1.6-fold increase of PKC-alpha and PKC-zeta with slight increase of PKC-delta in treatment with 5.0 muM, respectively. A small, but interesting discrepancy between the markedly elevated enzyme activity, which was composed particularly of both cofactor-independent forms, and the relatively low levels of isoform expression, was found when the cells were treated with 5.0 muM DXR. It is of great interest that DXR-treatment, while only slight increasing P-glycoprotein (Pgp) phosphorylation, enhanced the transient expression of Pgp on the cell membrane with good correlation with the fluctuating change in PKC activity. These results indicate that the possible expression of some or novel specific isoform(s) of PKC may modulate and be associated with expression of the Pgp.

Characteristic changes in protein-kinase-C activity and isoforms in ah66 cells during the acquisition of multidrug-resistant phenotype

Changes in enzyme activity and the isoform pattern of protein kinase C (PKC) during the process of acquiring of drug resistance to doxorubicin (DXR) was examined in rat ascites hepatoma AH66 parental cells (AH66P) and several established clones of DXR-resistant AH66DR cells. In the weakly resistant cell line, AH66DR-0.3, which was resistant to DXR at the concentration of 0.3 mu M, reduced PKC activity and significantly decreased expression of its isoforms (alpha, delta and zeta) were observed. By contrast, AH66DR-30, the clone with the highest resistance, showed increased PKC activity, which was mainly either Ca2+-independent and phospholipid-dependent or Ca2+-independent and phospholipid-independent. PKC-isoform analysis of the AH66DR-30 cells disclosed high levels of PKC-delta and -zeta and a quite low level of PKC-alpha relative to that of the AH66P cells. In both cell lines, phosphorylation of P-glycoprotein (Pgp), which is known as a drug efflux pump, was induced by PKC not only with Ca2+-dependent, but also with Ca2+-independent reactions. These results indicate that the expression of one or more specific isoform(s) of PKC, particularly the Ca2+-independent type, may be necessary for expression as well as activation of the function of Pgp.

Ca(2)Y(2)Cu(5)O(10): the first frustrated quasi-1D ferromagnet close to criticality

Ca(2)Y(2)Cu(5)O(10) is built up from edge-shared CuO(4) plaquettes forming spin chains. From inelastic neutron scattering data we extract an in-chain nearest-neighbor exchange J(1)≈-170  K and the frustrating next-neighbor J(2)≈32  K interactions, both significantly larger than previous estimates. The ratio α=|J(2)/J(1)|=0.19±0.01 places the system close to the critical point α(c)=0.25 of the J(1)-J(2) chain but in the 1D ferromagnetic regime. We establish that the vicinity to criticality only marginally affects the dispersion and coherence of the spin-wave-like magnetic excitations but instead results in a dramatic T dependence of high-energy Zhang-Rice singlet excitation intensities.

Mesenteric phlebosclerosis associated with long-term oral intake of geniposide, an ingredient of herbal medicine

BACKGROUND

Idiopathic mesenteric phlebosclerosis (IMP) is a rare disease, characterised by thickening of the wall of the right hemicolon with calcification of mesenteric veins. However, the aetiology remains unknown.

AIM

To investigate the possible association of herbal medicines with IMP.

METHOD

The clinical data of four of our own patients were collected. Furthermore, we searched for previous reports about similar patients with detailed descriptions of herbal prescriptions that they had taken. We compared herbal ingredients to identify the toxic agent as a possible aetiological factor.

RESULTS

Clinical data on a total of 25 patients were summarised. Mean age was 61.8 years and there was female predominance (6 men and 19 women). The used Kampo prescription, the number of cases, and the mean duration of use were as follows: kamisyoyosan in 12 cases for 12.8 years, inshin-iseihaito in 5 cases for 13.4 years, orengedokuto in 4 cases for 14.3 years, inchinkoto in 1 case for 20 years, kamikihitou in 1 case for 19 years, seijobofuto in 1 case for 10 years and gorinsan in 1 case for an unknown duration. Only one ingredient, sansisi, was common to the herbal medicines of all 25 patients. This crude drug called geniposide in English is a major constituent of the Gardenia fruits.

CONCLUSION

The long-term use of geniposide in herbal medicines appears to be associated with mesenteric phlebosclerosis.

magnetic dispersion and anisotropy in multiferroic BiFeO3

We have determined the full magnetic dispersion relations of multiferroic BiFeO3. In particular, two excitation gaps originating from magnetic anisotropies have been clearly observed. The direct observation of the gaps enables us to accurately determine the Dzyaloshinskii-Moriya (DM) interaction and the single ion anisotropy. The DM interaction supports a sizable magnetoelectric coupling in this compound.

Expression and analysis of a cytolethal distending toxin (cdt) gene operon in Campylobacter lari

The present study examines the expression of cytolethal distending toxin (cdt) gene encoding a cytotoxin in Campylobacter lari (n=6 urease-negative [UN] C. lari; n=4 urease-positive thermophilic Campylobacter [UPTC]). When reverse transcription polymerase chain reaction (RT-PCR) was carried out with 10 C. lari isolates using a primer pair to amplify the cdtB gene transcript segment, an approximate 260 bp RT-PCR amplicon was generated with all the isolates. In addition, cdtA, cdtB and cdtC gene operon was identified to be polycistronicly transcribed in the C. lari cells. The cdtB gene translation in the C. lari cells was also confirmed by Western blot analysis. Thus, the cdt gene operon in C. lari organisms, including UN C. lari and UPTC, was expressed at the transcriptional and translational levels in the cells. The present results suggest that all three cdt genes may be functional in the cells.

Comparative analysis of Campylobacter lari cytolethal distending toxin (CDT) effect on HeLa cells

We aimed to clarify if Campylobacter lari exerts a cytolethal distending toxin (CDT) effect on HeLa cells. Campylobacter cell lysates (CCLys) from C. jejuni 81-176 and urease-positive thermophilic Campylobacter (UPTC) CF89-12 and UPTC NCTC12893 isolates were shown to exert a CDT effect on HeLa cells with morphological changes examined by Giemsa staining and microscopy. However, Campylobacter lari JCM2530(T) isolate showed no effect. In addition, Campylobacter cell culture supernatant wash gave low or absent toxic effects with both C. jejuni and C. lari organisms. When western blot analysis was carried out to clarify if there was a CDTB effect in the CCLys and soluble fractions from Campylobacter isolates, which had a CDT effect on HeLa cells or did not have any effect, anti-recombinant CjCDTB antibodies identified an immunoreactively positive signal at around approximately 25 kDa on all the C. lari isolates examined, as well as the C. jejuni 81116 strain. Thus, all the Campylobacter isolates including those without any CDT effect were shown to express CDTB at the translational level.

Reliability of a multiplex PCR assay for the identification of the major Campylobacter taxa

The primer pair (C412F/C1228R) constructed previously for the polymerase chain reaction (PCR) identification of the genus Campylobacter using an approximate 800 base pair (bp) 16S rRNA gene target segment proved to be useful for the identification of a total of 49 Campylobacter lari isolates including urease-positive thermophilic Campylobacter (UPTC) organisms (n=25). When the primer pair (CLF/R) developed previously for the PCR identification of C. lari species using an approximate 250 bp glyA segment was employed, 27 C. lari isolates, including all the UPTC isolates, were identified to be PCR-negative (55%). Therefore, this PCR procedure developed for the molecular identification of C. lari was shown to be unreliable for C. lari identification. Nucleotide sequencing analysis clarified the reason(s) why PCR-negative examples occurred in many C. lari isolates, including UPTC isolates. The primer pair target sequences in the C. lari-specific PCR-negative isolates apparently varied at the 3' end region, as compared with C. lari-specific PCR-positive isolates. Thus, the multiplex PCR assay developed previously was shown to be unreliable for the molecular identification of C. lari subspecies organisms.

Magnetic structure of CuCrO₂: a single crystal neutron diffraction study

This paper presents results of a recent study of multiferroic CuCrO(2) by means of single crystal neutron diffraction. This system has two close magnetic phase transitions at T(N) = 24.2 K and T(mf) = 23.6 K. The low temperature magnetic structure below T(mf) is unambiguously determined to be a fully three-dimensional proper screw. Between T(N) and T(mf) antiferromagnetic order is found that is essentially two-dimensional. In this narrow temperature range, magnetic near neighbor correlations are still long range in the (H,K) plane, whereas nearest neighbors along the L direction are uncorrelated. Thus, the multiferroic state is realized only in the low temperature three-dimensional state and not in the two-dimensional state.

Molecular characterisation of the quinolone resistance-determining regions (QRDR) including gyrA, gyrB, parC and parE genes in Streptococcus pneumoniae

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia (CAP). Currently, empirical treatment with quinolones is being used due to the emergence of beta-lactam and macrolide resistance in S. pneumonaie. Although the prevalence of quinolone-resistant S. pneumoniae remains low, increasing numbers of resistant isolates are being seen. Genetic mechanisms leading to fluoroquinolone resistance in pneumococci are complex. This study aims to use molecular methods to characterise all isolates through sequence analysis of their QRDR regions. Thirty-two S. pneumoniae isolates were obtained from nasal swabs from adult and paediatric patients attending local general practices in Northern Ireland. Phenotypic minimum inhibitory concentration (MIC) was determined for Clinical and Laboratory Standards Institute (CLSI) broth microdilution against ciprofloxacin, levofloxacin and norfloxacin. Simultaneously, the QRDR regions of gyrA, gyrB, parC and parE were analysed by sequence typing for all pneumococci obtained. Only one isolate (3.1%) showed reduced susceptibility to ciprofloxacin and levofloxacin. Two amino acid positions were discordant in the S. pneumoniae R6 strain and eight (25%) and 23 (71.9%) isolates contained the mutations Ile460Val in gyrA and Lys137Asn in parC (deposited in GenBank, accession numbers GQ999587-GQ999589), respectively. No mutations were found in either the gyrB or parE loci. In conclusion, the study demonstrated increased fluoroquinolone resistance which could not be accounted for simply through QRDR mutations, and, reciprocally, that mutations in the QRDR region do not necessarily result in overt phenotypic resistance.

Exposure to clinical X-ray radiation does not alter antibiotic susceptibility or genotype profile in gram-negative and gram-positive clinical pathogens

Inadvertent exposure of bacterial pathogens to X-ray radiation may be an environmental stress, where the bacterium may respond by increasing mutational events, thereby potentially resulting in increased antibiotic resistance and alteration to genotypic profile. In order to examine this, four clinical pathogens, including the Gram-negative organisms Escherichia coli O157:H7 NCTC12900 and Pseudomonas aeruginosa NCTC10662, as well as the Gram-positive organisms Staphylococcus aureus NCTC6571 and Enterococcus faecium were exposed to X-rays (35,495 cGy/cm2) over a seven-day period. Antibiotic susceptibility was assessed before, during and after exposure by examining susceptibility, as quantified by E-test with six antibiotics, as well as to a further 11 antibiotics by measurement of susceptibility zone sizes (mm). Additionally, the DNA profile of each organism was compared before, during and after exposure employing the enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC PCR). Results indicated that exposure of these organisms to this amount of X-ray radiation did not alter their antibiotic susceptibility, nor their genomic DNA profile. Overall, these data indicate that exposure of bacteria to X-ray radiation does not alter the test organisms' antibiotic susceptibility profiles, nor alter genomic DNA profiles of bacteria, which therefore does not compromise molecular epidemiological tracking of bacteria within healthcare environments in which patients have been exposed to X-ray radiation.

Transient pulmonary edema following Adrenal Infarction in a patient with primary Anti-phospholipid syndrome

We report a patient with primary anti-phospholipid syndrome (APS) who developed pulmonary edema following sudden-onset pain in the left, lower back of the chest. Radiological examinations demonstrated fresh infarction of the left adrenal gland but no obvious thrombi in pulmonary arteries. The patient quickly recovered from pulmonary edema with anti-coagulation therapy alone. Primary APS may have caused adrenal infarction in the patient, leading to transient pulmonary edema via microthrombosis and/or excessive release of catecholamine.

Molecular characterisation of the quinolone resistance-determining region (QRDR) of the parC gene locus in viridans-group streptococci

Forty-eight isolates of viridans-group streptococci (VGS) from adults and children in the community are examined for their resistance to ciprofloxacin phenotypically by determination of the minimum inhibitory concentration (MIC). In addition, the parC gene locus is amplified and sequenced in all isolates and mutations noted. Overall, 44 VGS organisms were found to be susceptible to ciprofloxacin by the broth microdilution method, and the remaining four strains had intermediate susceptibility. Reduced MICs were observed with intermediate strains when reserpine was added to the broth, inhibiting any efflux activity. Overall, the effect of adding reserpine to the broth medium was to add one doubling dilution to the MIC in the case of Streptococcus mitis, S. oralis and S. salivarius, as well as to increase the MIC by two doubling dilutions in two of the three S. parasanguinis isolates. Amino acid sequence analysis of the quinolone resistance-determining region (QRDR) of the parC gene locus showed good correlation to the phenotypic resistance to ciprofloxacin, where no confirmed mutation conferring quinolone resistance was found. Eleven amino acid positions showed discordance with S. pneumoniae R6 and eight (S52, F55, S58, N91, E135, K137, F141 and S167) were common in the VGS species examined. In addition, minor substitutions were found at three positions (D51, T54 and V86). In conclusion, this study demonstrates the low occurrence of ciprofloxacin resistance in a population of VGS isolated from the community. In addition, several silent mutations were noted in VGS organisms without any increase in MIC against ciprofloxacin.

Molecular identification and characterization of clustered regularly interspaced short palindromic repeats (CRISPRs) in a urease-positive thermophilic Campylobacter sp. (UPTC)

Novel clustered regularly-interspaced short palindromic repeats (CRISPRs) locus [7,500 base pairs (bp) in length] occurred in the urease-positive thermophilic Campylobacter (UPTC) Japanese isolate, CF89-12. The 7,500 bp gene loci consisted of the 5'-methylaminomethyl-2-thiouridylate methyltransferase gene, putative (P) CRISPR associated (p-Cas), putative open reading frames, Cas1 and Cas2, leader sequence region (146 bp), 12 CRISPRs consensus sequence repeats (each 36 bp) separated by a non-repetitive unique spacer region of similar length (26-31 bp) and the phosphatidyl glycerophosphatase A gene. When the CRISPRs loci in the UPTC CF89-12 and five C. jejuni isolates were compared with one another, these six isolates contained p-Cas, Cas1 and Cas2 within the loci. Four to 12 CRISPRs consensus sequence repeats separated by a non-repetitive unique spacer region occurred in six isolates and the nucleotide sequences of those repeats gave approximately 92-100% similarity with each other. However, no sequence similarity occurred in the unique spacer regions among these isolates. The putative σ(70) transcriptional promoter and the hypothetical ρ-independent terminator structures for the CRISPRs and Cas were detected. No in vivo transcription of p-Cas, Cas1 and Cas2 was confirmed in the UPTC cells.

Molecular and comparative analyses of the full-length cytolethal distending toxin (cdt) gene operon and its adjacent genetic loci from urease-positive thermophilic Campylobacter (UPTC) organisms

Molecular and comparative analyses of the full-length cytolethal distending toxin (cdt) gene operon and its adjacent genetic loci (2.7-9.4 kilo base pairs in length) are carried out with 12 urease-positive thermophilic Campylobacter (UPTC) isolates using several polymerase chain reaction (PCR) primer pairs. Three putative open reading frames (ORFs) for cdtA, cdtB and cdtC, two putative promoters and a hypothetically intrinsic rho-independent transcription terminator were identified in all the operons of the 12 UPTC isolates examined. Although the number of amino acid residues slightly varied for the putative cdtA and cdtC ORFs, those for the cdtB were similar among all the UPTC isolates, as well as the six urease-negative (UN) C. lari examined previously. Regarding the cdt genes in UPTC CF89-12, each ORF commenced with an ATG start codon and terminated with a TAG stop codon for cdtA and cdtB and a TAA for cdtC. Start and stop codons of the three ORFs for the other 11 UPTC isolates were identical to those from the UPTC CF89-12 isolate except for the TTG start codon for cdtC in the two isolates (NCTC12892 and 12893) and the TGA stop codon for cdtA in five isolates (A1, A2, A3, 89049 and 92251). Two putative promoter structures, consisting of sequences at the -35-like (TTAATA) and -10-like (TATTAA) regions, as well as the start codon (ATG), were identified for the transcriptional promoter, immediately upstream of the cdtA gene in all the 12 isolates, Although the genetic heterogeneity of the cdtB gene locus occurred in all 28 C. lari isolates (n = 16 UN C. lari; n = 12 UPTC) examined, all nine amino acid-specific DNase residues were completely conserved in all their cdtB genes. Variable gene insertions with heterogeneous order and combinations occurred between cdtC and lpxB genes in the all UPTC organisms examined.

Uneven distribution of the luxS gene within the genus Campylobacter

Polymerase chain reaction (PCR) amplification was performed on 20 isolates of five Campylobacter species using a degenerate primer pair designed in silico to generate a product of the luxS gene or its homologue from Campylobacter organisms. Although the primer pair successfully amplified products of approximately 500 base pairs (bp) with the eight isolates of C. jejuni and C. coli and some of C. upsaliensis and C. fetus, it failed to amplify fragments with all four isolates of C. lari (two urease-negative C. lari; two urease-positive thermophilic campylobacters). When Southern blot hybridisation analysis was carried using the mixed luxS gene fragments prepared from the C. jejuni, C. coli, C. upsaliensis and C. fetus strains as a probe, all C. jejuni, C. coli, C. upsaliensis and C. fetus isolates gave positive signals, but no positive signal was detected with any C. lari isolate. These results clearly indicate that C. jejuni, C. coli, C. upsaliensis and C. fetus carry the luxS gene or its homologue. However, no luxS gene or its homologue was identified to occur in the C. lari genome. Although autoinducer-2 assays were positive in C. jejuni, C. coli, C. upsaliensis and C. fetus isolates, it was negative with all the C. lari isolates examined. In addition, a biofilm formation assay demonstrated that biofilm formation in the C. lari species does not appear to correlate with the occurrence of the luxS gene because biofilm formation occurred among some isolates of C. lari.