Toxic inhalation of sodium metabisulphite by-products from a shipping container.

Logistics workers who handle cargo containers are at risk of toxic inhalation injuries, although prevalence and severities of these injuries are not well characterized. We report on a previously healthy 37-year-old supervisor who was acutely exposed to sodium metabisulphite and its thermal degradation by-products during a routine inspection of a shipping container. The employee developed chemical pneumonitis with acute non-cardiogenic pulmonary oedema and subsequent severe reactive airway dysfunction syndrome.

Expression of coagulin A with low cytotoxic activity by Pediococcus pentosaceus ST65ACC isolated from raw milk cheese.

AIMS: We aimed to evaluate some specific conditions for growth of Pediococcus pentosaceus ST65ACC and its bacteriocin expression through ABC transporters; to purify the bacteriocin and determine its sequence; and to evaluate the cytotoxicity potential of the purified bacteriocin(s). METHODS AND RESULTS: The results presented for growth behaviour of P. pentosaceus ST65ACC showed that the bacterial growth was slightly influenced when cultured in MRS broth with different amounts of inoculum: 1, 2, 5 and 10%. The bacteriocin activity increased when 5 and 10% inocula were used. The carbon source (glucose) used in different amounts (1, 2, 3 or 4%) had no significant effect on growth and bacteriocin production. The studied strain P. pentosaceus ST65ACC was able to metabolize xylooligosaccharide (XOS) as the sole carbon source, resulting in the production of an antimicrobial peptide. The genes involved in the ABC transport system and sugar metabolism of P. pentosaceus ST65ACC were expressed at different levels. The bacteriocin produced by P. pentosaceus ST65ACC was partially purified by precipitation with ammonium sulphate (40% saturation), followed by reversed-phase liquid chromatography, resulting in the identification of an active bacteriocin. Tandem mass spectrometry was used to identify the partial sequence KYYGNGVTCGKHSCSVDWGK sharing high similarity to coagulin A. The semi-purified bacteriocin had low cytotoxicity based on estimated values for maximal nontoxic concentration (MNC) and cytotoxicity concentration (CC50 ). CONCLUSIONS: The bacteriocin produced by P. pentosaceus ST65ACC is similar to coagulin, with low cytotoxicity, strong antimicrobial activity and possible additional metabolite routes in the producer cell. In addition to MRS broth, bacteriocin was produced also in medium containing XOS (as the single carbon source). SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is the first report of evaluation of the role of ABC transporters in the expression of bacteriocin by P. pentosaceus, cultured in MRS and XOS.

Self-induced steady-state magnetic field in the negative ion sources with localized rf power deposition.

The study is in the scope of a recent activity on modeling of SPIDER (Source for Production of Ions of Deuterium Extracted from RF plasma) which is under development regarding the neutral beam injection heating system of ITER. The regime of non-ambipolarity in the source, established before, is completed here by introducing in the model the steady state magnetic field, self-induced in the discharge due to the dc current flowing in it. Strong changes in the discharge structure are reported.

Spatial distribution of the plasma parameters in a radio-frequency driven negative ion source.

Results from initial stage of modeling of the SPIDER source of negative hydrogen/deuterium ions currently under development in Consorzio RFX (Padova) regarding ITER are presented. A 2D model developed within the fluid plasma theory for low-pressure discharges (free-fall regime maintenance) is applied to the gas-discharge conditions planned and required for the SPIDER source: gas pressure of 0.3 Pa and radio-frequency (rf) power of 100 kW absorbed in a single driver. The results are for the spatial distribution of the plasma characteristics (charged particle densities, electron temperature and electron energy flux, plasma potential, and dc electric field) with conclusions for the role of the electron energy flux in the formation of the discharge structure.

[Replication of the subgenomic hepatitis C virus replicon in the presence of the NS3 protease inhibitors: a stochastic model].

The hepatitis C virus (HCV) belongs to Flaviviridae family and causes hazardous liver diseases leading frequently to cirrhosis and hepatocellular carcinoma. HCV is able to rapidly acquire drug resistance and for this reason there is currently no effective anti-HCV therapy in spite of appearance of new potential drugs. Mathematical models are relevant to predict the efficacy of potential drugs against virus or host targets. One of the promising targets for development of new drugs is the viral NS3 protease. Here we developed a stochastic model of the subgenomic HCV replicon replication in Huh-7 cells and in the presence of the NS3 protease inhibitors. Along with consideration of the stochastic nature of the subgenomic HCV replicon replication the model takes into account the existence and generation of main NS3 protease drug resistant mutants, namely BILN-2061 (A156T, D168V, R155Q), VX-950 (A156S, A156T, T54A) and SCH-503034 (A156T, A156S, T54A). The model reproduces well the viral RNA kinetics in the cell from the moment of the subgenomic HCV replicon transfection to steady state, as well as the viral RNA suppression kinetics in the presence of NS3 protease inhibitors BILN-2061, VX-950 and SCH-503034. We showed that the resistant mutants should be taken into account for the correct description of biphasic kinetics of the viral RNA suppression. The mutants selected in the presence of different inhibitor concentrations have maximal replication capacity in the given inhibitor concentration range. Our model can be used to interpret the results of the new anti-HCV drug testing in replicon systems, as well as to predict the efficacy of new potential drugs and optimize the regimen of their use.

Comparative assessment of the cytotoxic effects of carboxylato-bridged dinuclear platinum (II) complexes against human tumor cell lines.

The cytotoxic effects of a series of carboxylato-bridged dinuclear platinum (II) complexes with acetate (BAP), propionate (BPP) and valerate (BVP) ligands were evaluated in a panel of human tumor cell lines. BAP proved to be the most potent antineoplastic agent, whose cytotoxic effect reached and even outclassed that of the referent drug cisplatin. This compound also exerted substantial efficacy against a broader spectrum of tumor models including the multidrug-resistant HL-60/Dox cell line. In the latter case, BAP showed lower resistance index than cisplatin. BAP was furthermore found to induce apoptosis in different cell lines as evidenced by DNA-laddering and Cell-death ELISA. Our experimental data give us reason to conclude that the dinuclear Pt(II) complex with acetate ligands is perspective for further detailed pharmacological and toxicological evaluation as an antineoplastic drug candidate.

Effect of Putrescine, 4-PU-30, and Abscisic Acid on Maize Plants Grown under Normal, Drought, and Rewatering Conditions.

The experiments were carried out with maize (Zea mays L.) seedlings, hybrid Kneja 530, grown hydroponically in a growth chamber. Twelve-day-old plants were foliar treated with putrescine, N1-(2-chloro-4-pyridyl)-N2-phenylurea (4-PU-30), and abscisic acid (ABA) at concentrations of 10(-5) m. Twenty-four hours later the plants were subjected to a water deficit program, induced by 15% polyethylene glycol (PEG; molecular weight, 6,000). Three days after drought stress half of the plants were transferred to nutrient solution for the next 3 days. The effects of the water shortage, rewatering, and plant growth regulator (PGR) treatment on the fresh and dry weights, leaf pigment content, proline level, relative water content (RWC), transpiration rate, activities of catalase and guaiacol peroxidase, hydrogen peroxide content, and level of the products of lipid peroxidation were studied. It was established that the application of PGRs alleviated to some extent the plant damage provoked by PEG stress. At the end of the water shortage program the plants treated with these PGRs possessed higher fresh weight than drought-subjected control seedlings. It was found also that putrescine increased the dry weight of plants. Under drought, the RWC and transpiration rate of seedlings declined, but PGR treatment reduced these effects. The accumulation of free proline, malondialdehyde, and hydrogen peroxide was prevented in PGR-treated plants compared with the water stress control. The results provided further information about the influence of putrescine, 4-PU-30, and ABA on maize plants grown under normal, drought, and rewatering conditions. Key Words. Maize-Putrescine-4-PU-30-ABA-Drought

Comparison of three urease tests for detection of Helicobacter pylori in gastric biopsy specimens.

OBJECTIVE: To propose two modified urease tests for the detection of Helicobacter pylori in gastric biopsy specimens. PATIENTS AND METHODS: The presence of H. pylori infection was determined in 237 patients undergoing upper gastrointestinal endoscopy. Three media were used for the urease tests: Christensen's 2% urea broth and two urea agar media, modified by increasing the concentration of urea (to 4% and 10%) and phenol red and omitting the nutrients. RESULTS: The modified tests had good sensitivity (> 78%), specificity (96%) and accuracy (> or = 86%) at 2 h using small amounts (15%) of biopsy homogenates. They were statistically more sensitive and accurate than Christensen's broth. CONCLUSION: Both the modified 4% and 10% urea agar tests are simple, sensitive and specific and can be performed with small amounts of sample.

Does verapamil help overcome multidrug resistance in tumor cell lines and cancer patients?

The aim of these experimental and clinical studies was to determine if verapamil helps overcome multidrug resistance in tumor cells and in cancer patients. The effect of the calcium channel blocker verapamil on the antiproliferative activity of epirubicin (Farmorubicin, Farmitalia) was followed up in in vitro studies on two constant human leukemia cell lines: CEM/O (P-gp negative) and CEM/VCR 1000 with a positive multidrug resistant (MDR) phenotype. The MTT assay was used to study the antiproliferative activity. Verapamil in concentrations of 3 and 10 micrograms/ml enhanced by 10-fold and 19-fold, respectively, the effect of epirubicin in CEM/VCR 1000 cells and had no significant effect on epirubicin activity in CEM/O. Eleven patients with measurable stage IV breast cancer, clinically resistant to anthracycline treatment, received the FEC combination (5-fluorouracil-epirubicin-cyclophosphamide) twice with verapamil pretreatment, p.o. at the doses of 1280-2560 mg. There were two complete remissions (soft tissue metastases), four partial remissions (soft tissue metastases and lung metastases), and three stable diseases. These studies confirm the possibilities of overcoming multidrug resistance by the administration of verapamil in tumor cells and in cancer patients.

Cell cycle effects of thaliblastine.

The non-myelotoxic antitumor drug thaliblastine (thalicarpine, NSC-68075, CAS-5373-42-21) has a novel chemical structure; it is a complex dimeric-type aporphine benzylisoquinoline alkaloid possessing antiproliferative and antitumor activities in experimental and clinical studies. In this study the effect of this drug on the cell cycle progression of ovarian tumor line O-342 and its cisplatin-resistant subline O-342/DDP was evaluated. As assessed by flow cytometric analysis, thaliblastine affected the cell cycle progression. In both lines, a comparable pattern of cell cycle arrest was found. Within the first 5 h of thaliblastine exposure, a G2/M block was observed; thereafter cell-cycle arrest in G1 became prominent, while S-phase cells finished DNA replication.

Antiproliferative activity of liposomal epirubicin on experimental human gliomas in vitro and in vivo after intratumoral/interstitial application.

Liposomal epirubicin was prepared using the controlled detergent dialysis method. The entrapment rate was 65.5 +/- 6.4%. The mean particle size was 210 +/- 38 nm. In vitro, a concentration-dependent antiproliferative activity of free epirubicin was observed. Liposome-entrapped epirubicin was superior to the free drug; the ID50 of the liposomal preparation was about 1.6-fold lower as compared to the free drug. Intratumoral/interstitial (i.t./i.s.) application of liposomal epirubicin was likewise superior to i.t./i.s. application of the free drug.

Spin labeled amino acid nitrosourea derivatives--synthesis and antitumour activity.

The synthesis of three spin labeled derivatives of N-[N'-(chloroethyl)-N'-nitrosocarbamoyl] amino acids is reported. The new nitrosoureas are obtained by condensation of the corresponding N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl] amino acid with 2,2,6,6-tetramethyl-1-oxyl-4-aminopiperidine using dicyclohexylcarbodiimide. Their chemical structures are confirmed by elemental analysis, IR, MS, and EPR spectroscopy. All newly synthesized compounds showed high antitumour activity against the lymphoid leukemia L1210 in BDF1 mice.

Dominant-lethal mutations and micronucleus induction in male BALB/c, BDF1 and H mice by tobacco smoke.

The mutagenicity of whole tobacco smoke (TS) was examined in male BALB/c, BDF1 and H mice using the dominant lethal and micronucleus tests in bone marrow polychromatic erythrocytes. Male mice (about 80 days old) from the three strains were treated with TS on 5 days/week for 8 weeks. The animals were divided into three groups for every strain: control and two experimental groups. Two doses--low (1h treatment/day) and high (2 h treatment/day)--were used. In the first case 8 exposures of 7.5 min each with 1-min intervals were given and to realize the high dose this was repeated 4 h later. It was found that TS induces significant dominant-lethal mutations in both experimental groups of BALB/c, BDF1 and H mice (p < 0.001), but some strain differences existed. The data obtained suggest that in BALB/c and BDF1 mice TS induces dominant-lethal mutations mainly in spermatocytes, spermatogonia and gonial stem cells, while in H mice only spermatids and spermatocytes are affected. The bone marrow from each strain and each dose group was investigated for the presence of micronucleated polychromatic erythrocytes (PCE) at 5, 19, 38, 54, and 63 days after beginning of the treatment with TS, using the same exposure regimen. Exposure of male mice to TS caused an up to 2-3-fold increase in the number of PCE in the bone marrow of BALB/c and BDF1 mice in both dose groups. In H mice this effect is observed only on days 19 and 38 of sampling. No cumulative or dose-dependent effects were detected. Increased formation of micronuclei within PCE of femoral bone marrow after passive smoking was regarded as being due to the effect of TS.

Collateral sensitivity to thaliblastine and/or hyperthermia exhibited by a rat ovarian tumor cell line selected for resistance to cisplatin.

Drug resistance severely limits the effectiveness of clinical cancer chemotherapy. Employment of drugs other than the selected compounds with different mechanisms of action may provide a potential way to improve the therapeutic effects. Thaliblastine (TBL), a natural compound, showed a 2-fold higher cytotoxicity in a cisplatin (DDP) resistant rat ovarian tumor cell line (0-342/DDP) than in its parental sensitive line (0-342), as determined by an antiproliferation assay with 24 h continuous exposure. This phenomenon was also observed following 2 h pulse exposure if combined with heat treatment (40 degrees C). Further escalation of the temperature to 43 degrees C alone brought about 74.7 +/- 17.0% growth inhibition in the sensitive and 97.2 +/- 1.8% in the resistant line. Under this condition, the ID50 of TBL was again only half as much in 0-342/DDP cells as in the parental cells (12 vs 24 micrograms/ml) when compared to the hyperthermic treatment alone. In a colony formation assay with 2 h pulse exposure, the hypersensitivity of the resistant cells to DDP and/or heat was further confirmed. Alkaline elution showed that 24 h continuous treatment with TBL induced DNA single-strand breaks (SSB) in a dose-dependent manner in 0-342/DDP cells, whereas there was almost no DNA-SSB production by TBL in the sensitive line, possibly in part accounting for the hypersensitivity of the DDP resistant cells to TBL. The heat treatment (40 degrees C for 2 h) induced SSB in both lines, which was further enhanced by combination with TBL. This damage was repaired in part in 0-342 but almost completely in 0-342/DDP line after cells grew in drug-free medium for 48 h following the exposure, indicating that resistant cells can more efficiently repair DNA damage by either TBL or hyperthermia. Altogether, these results suggest that TBL may have potential to be used clinically as an alternative in the treatment of cisplatin-resistant malignancies with hyperthermia.

Antitumor activity of thaliblastine (NSC-68075) in experimental ovarian tumor cell lines sensitive and resistant to cisplatin.

Cytotoxicity of thaliblastine (thalicarpine, TBL; NSC-68075) and/or cisplatin (DDP) in DDP-sensitive (O-342) and-resistant (O-342/DDP) rat ovarian tumor cell lines was comparatively determined using the MTT assay. The 50% inhibitory dose (ID50) of DDP was found to be 6.2 microM in O-342 cells and 23.4 microM in O-342/DDP cells, while, vice versa, the ID50 of TBL was 39.3 micrograms/ml in the sensitive line and 27.3 micrograms/ml in the resistant line. Furthermore, simultaneous exposure of cells to DDP and TBL showed a significant superiority over DDP alone in O-342 cells, as evaluated with variance analysis (P less than 0.001). This enhancing effect of TBL on DDP cytotoxicity, however, was not observed in the resistant cells.

Antiproliferative activity of the non-myelotoxic antitumour agent of plant origin, Thaliblastine, on two human glioma cell lines.

The antiproliferative activity of the non-myelotoxic antitumour agent of plant origin, Thaliblastine, on two human glioma cell lines is described. Thaliblastine was added once one day following start of culture; proliferation was monitored over 7 days. The antiproliferative activity of Thaliblastine was strongly dependent on concentration and time of incubation. The ID50 of Thaliblastine in T406 and GW27 glioma lines was 5.1 micrograms/ml and 8.2 micrograms/ml (7.0 microM and 11.2 microM), respectively.