Comparative ecotoxicity of single and binary mixtures exposures of cadmium and zinc on growth and biomarkers of Lemna gibba

In the present study, single and mixture effects of cadmium (Cd) and zinc (Zn) on Lemna gibba were analyzed and compared using growth parameters, based on frond number and fresh weight, and biochemical parameters, such as pigment, protein content and activity of antioxidant enzymes. Plants were exposed for 7 days to these metals in nutrient solution. Single and mixture exposures affected plant growth and the biomarkers of the antioxidant response. Considering the growth parameters, Cd was found to be much more toxic than Zn. IC50-7d, based on growth rate calculated on frond number, were 17.8 and 76.73 mg/L, and on fresh weight were 1.08 and 76.93 mg/L, for Cd and Zn respectively. For Cd, LOEC values were obtained at 2.06 and 1.03 mg/L, for frond number and fresh weight respectively; while for Zn, at 20.1 and 74.6 mg/L. A high toxicity effect, considering the same response variables, was observed in plants exposed to the mixtures. Three fixed ratios, based on toxic units (TU) were assayed, ratio 1: 2/3 Cd−1/3 Zn, ratio 2: 1/2 Cd−1/2 Zn and ratio 3: 1/3 Cd−2/3 Zn. Ratio 3 (where Zn was added in higher proportion) was the less toxic. All concentrations of Ratio 1 and 2 significantly inhibited plant growth, showing a 100% inhibition of growth rate at the highest concentrations when based on frond number. Catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APOX; EC 1.11.1.11) and guaiacol peroxidase (GPOX; EC 1.11.1.7) activities in single metals assays were higher than controls. In mixture tests, the activity of APOX and GPOX was significantly stimulated in plants exposed to all evaluated combinations, while CAT was mainly stimulated in Ratio 3. It was observed that the activity of the enzymes was increased in the mixtures compared with similar concentrations evaluated individually. APOX activity was observed to fit the CA model and following a concentration-response pattern. The response of this antioxidant enzyme could serve as a sensitive stressor biomarker for Cd–Zn interactions. Frond number in Cd–Zn mixtures was not well predicted from dissolved metal concentration in solution using concentration addition (CA) as reference model, as results showed that toxicity was more than additive, with an average of ΣTU = 0.75. This synergistic effect was observed up to 50 mg Zn/L in the mixture, but when it was present in higher concentrations a less than additive effect was observed, indicating a protective effect of Zn. A synergistic and dose-ratio deviations from CA model were also observed.     

Vertical transmission of hepatitis C Virus: An epidemiological study on 2,980 pregnant women in Italy

The risk of mother-to-infant transmission of hepatitis C virus (HCV) varies according to the population studied and the tests used. Aim of the current study was to investigate HCV vertical transmission rate in children born to 30 HCV positive/HIV negative pregnant women in Italy. We investigated the potential vertical transmission of HCV by identifying HCV antibody seropositive pregnant women, by analyzing HCV-RNA in the peripheral blood using PCR and by prospectively following their offspring until 24 months of age. During the third trimester, 2,980 consecutive pregnant women were examined for anti-HCV antibodies by a second generation Enzyme-Linked Immunosorbent Assay (EIA2) and re-assayed by a second generation Recombinant Immunoblot Assay (RIBA2). A total of 32 mothers (1.07%) were positive for EIA2 test; 30 out of 32 had a reactive confirmatory RIBA2 test for HCV All anti-HCV positive mothers were negative for HIV. These 30 mothers and their 30 babies formed the study cohort. Of the 30 anti-HCV positive mothers, 10 were also positive for serum HCV-RNA by PCR. All the babies born to the 30 anti-HCV positive mothers were initially negative for HCV-RNA (cord blood specimens), but three babies became positive at three months of age and remained positive thereafter. These babies had been born to 3 of the 10 mothers with viremia during the third trimester of pregnancy. These results suggest that HCV vertical transmission is possible in 10% of anti-HCV positives and in about 33% of the HCV-RNA seropositive mothers.     

Effect of cholinergic agonists and antagonists on gallbladder volume in fasting man

Summary The effect of direct cholinergic stimulation and blockade on gallbladder volume, determined by real-time ultrasonography (RUS), was evaluated in twenty normal, fasting subjects. Eleven subjects received atropine sulphate or placebo and 9 subjects a series of 3 injection of prostigmine, bethanechol or placebo, randomly assigned, at intervals of 24 h.RUS was performed under basal conditions after fasting for 12 h and every 5 min after drug injection up to 45 min in the atropine study and up to 60 min after prostigmine and bethanechol.There was no significant variation from fasting gallbladder volume after placebo in either group. After atropine sulphate gallbladder volume at first decreased and then significantly increased. With bethanechol and prostigmine, the volume fell significantly to a trough after 30 to 35 min, and then it returned to the basal value within 60 min. It is suggested that cholinergic mediation is involved in maintaining fasting tone in the gallbladder and that cholinergic stimulation causes contraction of the gallbladder by a direct effect.     

Designing novel pH-sensitive non-phospholipid vesicle: Characterization and cell interaction

In an effort to enhance the oral bioavailability of scutellarin, ethyl, benzyl and N,N-diethylglycolamide ester of scutellarin were synthesized. The hydrolysis of the prodrugs follows first-order kinetics in aqueous solution, and produced a V-shaped pH profile. The N,N-diethylglycolamide ester is highly susceptible to enzymatic hydrolysis in human plasma (t_1/2 ≈ 7 min) with a high stability in aqueous solution (t_1/2 ≈ 16 day, pH 4.2). Compared with the solubility of scutellarin, the solubility of glycolamide ester was about ten times in pH 4.0 buffer, and about thirty five times in water. Its apparent partition coefficient increased significantly from −2.56 to 1.48. Glycolamide ester of scutellarin was chosen to investigate the intestinal metabolism and in vivo bioavailability. Degradation studies in the intestinal tract content and homogenates indicated intestinal metabolism before absorption was a crucial obstacle for the prodrug. N,N-Diethylglycolamide ester can be protected from the degradation in the intestinal lumen by an emulsion. A significant increase in the plasma AUC and C_max of the prodrug emulsion was observed in rats, compared with that of the scutellarin–cyclodextrin complex (P < 0.01). The emulsion of N,N-diethylglycolamide ester produces a 1.58-fold enhancement in apparent bioavailability and 1.4-fold increase in the absolute bioavailability compared to the scutallarin–cyclodextrin complex.     

A replication-competent adenovirus assay for E1-deleted Ad35 vectors produced in PER.C6 cells

The presence of replication-competent adenovirus (RCA) is a safety concern for biologics based on recombinant adenoviruses and RCA testing is therefore mandatory for release of clinical material. RCA, which arises from homologous recombination between Ad5 vectors and HEK-293 cells, can be eliminated by the use of PER.C6 cells in combination with a matched vector. However, little is known on RCA formation with vectors based on adenovirus serotypes other than Ad5 and reliable RCA assays to test them are generally lacking. Here we report on the development and qualification of a sensitive RCA assay for Ad35, a promising alternative to Ad5 vectors. The assay is able to detect 1 RCA in 3x10(10) vector particles with 95% confidence, thus meeting current FDA requirements, and can discriminate between RCA and other rare CPE-causing entities, including helper dependent E1 positive particles (HDEP). Using this assay, the first batches of Ad35 vectors produced in PER.C6 cells were analysed and found to be free of RCA and HDEP. Based on the statistical model used, we anticipate that our approach to RCA assay development can be broadly applicable to other adenoviral vectors.     

A sensitive cell-based assay for the detection of residual infectious West Nile virus

Ensuring complete viral inactivation is critical for the safety of vaccines based on an inactivated virus. Detection of residual infectious virus is dependent on sensitivity of the assay, sample volume analyzed and the absence of interference with viral infection. Here we describe the development and qualification of a sensitive cell-based assay for the detection of residual infectious West Nile Virus (WNV). The results of the assay are in good agreement with the assumption that at low concentrations the number of infectious units in relatively small samples follows a Poisson distribution. The assay can detect 1 infectious unit with a confidence of 99%, provides statistical controls for interference and can easily be scaled up to test large amounts of vaccine material. Furthermore, we show equivalence in sensitivity between the cell-based assay and an in vivo assay for detection of infectious WNV. Finally, the assay has been used for successful release testing of clinical lots of inactivated WNV vaccine. Given the principle and generic setup of the method we envision broad applicability to the detection of very low concentrations of infectious virus.     

Analysis of prognostic factors in 106 cases of carcinoma of the rhinopharynx treated with cobalt teletherapy

A series of 106 patients affected with nasopharyngeal carcinomas and treated by definitive external irradiation from January 1975 to December 1986 was retrospectively reviewed. The median follow-up, from the end of the treatment, was 43 months (range 24-90). The nasopharynx received not less than 60 Gy to the midplane: the clinically negative neck (N0) was treated with a total dose of 50 Gy and the patients who had N1-3 disease received not less than 60 Gy. Thirty-eight patients had a recurrence in the irradiated areas (31 in the nasopharynx, and 7 in the neck); 17 patients developed distant metastases. Disease-free survival at 60 months was 42%. The most significant prognostic factor (p less than 0.05) was the presence of advanced neck involvement (N2-3), since most of the lymphatic and distant recurrences were observed in this group of patients. The overall results did not reveal but slight differences in the survival according to histology, even though patients with undifferentiated carcinomas had a local recurrence rate significantly lower than those with squamous cell carcinomas. Our findings suggest that patients with N2-3 neck diseases or with locally advanced involvement (T3-4) be treated by adjuvant chemotherapy in order to decrease the risk of local and distant relapses.     

Motor effect of dopamine on human sigmoid colon. Evidence for specific receptors

The effect of dopamine on human sigmoid motility has been studied in 26 subjects. To record mechanical activity of the sigmoid colon, two small, air-filled balloons mounted on a probe introduced through a sigmoidoscope were used. The recordings were made at a distance of 25 and 15 cm from the anal edge. Dopamine was infused for 10 min after a 30-min control infusion of physiologic solution. Mean amplitude, mean duration, mean frequency, percentage of motor activity, and motility index of the pressure waves were determined. The motor response to dopamine was characterized by an increased baseline pressure with phasic waves superimposed. Dopamine produced a significant response at the dose of 5 microgram/kg/min. Alpha and beta antagonizing agents failed to oppose the effect of dopamine, while anticholinergic drugs enhanced its motor action. These studies suggest that dopamine may stimulate the motor function of human large bowel through specific receptors.