DNA susceptibility of Saccharomyces cerevisiae to Zeocin depends on the growth phase.

The aim of this study was to evaluate the level of Zeocin-induced double-strand breaks (DSBs) in Saccharomyces cerevisiae cells in a different growth phase, using constant-field gel electrophoresis (CFGE). Saccharomyces cerevisiae diploid strain D7ts1 with enhanced cellular permeability was used. The effects of growth phase and treatment time were evaluated based on Zeocin-induced DSBs, measured by CFGE.

Providing free pregnancy test kits to community health workers increases distribution of contraceptives: results from an impact evaluation in Madagascar.

Objectives: To improve access to contraceptives in remote and rural areas, sub-Saharan African countries are allowing community health workers (CHWs) to distribute hormonal contraceptives. Before offering hormonal contraceptives, CHWs must determine pregnancy status but often lack a reliable way to do so. No studies have evaluated the impact of providing CHWs with urine pregnancy test kits.

Antioxidant, antimutagenic, and anticarcinogenic effects of Papaver rhoeas L. extract on Saccharomyces cerevisiae.

The aim of this work was to analyze the antioxidant and antimutagenic/anticarcinogenic capacity of Papaver rhoeas L. water extract against standard mutagen/carcinogen methyl methanesulfonate (MMS) and radiomimetic zeocin (Zeo) on a test system Saccharomyces cerevisiae. The following assays were used: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, quantitative determination of superoxide anion (antireactive oxygen species [antiROS test]), DNA topology assay, D7ts1 test--for antimutagenic--and Ty1 transposition test--for anticarcinogenic effects.

Antioxidant and HSP70B responses in Chlamydomonas reinhardtii genotypes with different resistance to oxidative stress.

Today, the information from model species that differ in their resistance to oxidative stress and the determination of suitable plant markers for screening stress-resistant genotypes are essential for better understanding of plant stress responses and for selection. Here we aimed to assess the differences in antioxidant and HSP70B responses to paraquat treatment between genotypes susceptible and resistant to oxidative stress. Four genotypes of Chlamydomonas reinhardtii were chosen as a model of plant cells: two susceptible genotypes: wild type and paraquat-sensitive; and two paraquat-resistant genotypes: with high and moderate resistance.

Heat shock protein HSP70B as a marker for genotype resistance to environmental stress in Chlorella species from contrasting habitats.

The cellular response of three Chlorella species that differ in their temperature preferences and tolerance - Chlorella vulgaris - Antarctic, C. vulgaris strain 8/1 - thermophilic, and Chlorella kesslery - mesophilic - is analysed. Interspecies variability is found for the sensitivity of the species, with respect to the constitutive and induced levels of HSP70B.

A community-based approach to promote household water treatment in Rwanda.

Treatment of drinking water at the household level is one of the most effective preventive interventions against diarrhea, a leading cause of illness and death among children in developing countries. A pilot project in two districts in Rwanda aimed to increase use of Sûr'Eau, a chlorine solution for drinking water treatment, through a partnership between community-based health insurance schemes and community health workers who promoted and distributed the product. Evaluation of the pilot, drawing on a difference-in-differences design and data from pre- and post-pilot household surveys of 4,780 households, showed that after 18 months of pilot implementation, knowledge and use of the product increased significantly in two pilot districts, but remained unchanged in a control district.

Extract of Lillium candidum L. can modulate the genotoxicity of the antibiotic zeocin.

Lilium candidum L. extract (LE) is well known in folk medicine for the treatment of burns, ulcers, inflammations and for healing wounds. This work aims to clarify whether the genotoxic potential of the radiomimetic antibiotic zeocin (Zeo) could be modulated by LE.

Health workforce attrition in the public sector in Kenya: a look at the reasons.

Background: Kenya, like many other countries in sub-Saharan Africa, has been affected by shortages of health workers in the public sector. Data on the rates and leading reasons for health workers attrition in the public sector are key in developing effective, evidence-based planning and policy on human resources for health.

Methods: This study analysed data from a human resources health facility survey conducted in 2005 in 52 health centres and 22 public hospitals (including all provincial hospitals) across all eight provinces in Kenya.

Does single-dose cell resistance to the radio-mimetic zeocin correlate with a zeocin-induced adaptive response in Chlamydomonas reinhardtii strains?

This study aimed to test whether a correlation exists between single-dose resistance to zeocin and the ability to develop a zeocin-induced adaptive response (AR) in Chlamydomonas reinhardtii strains. Three genotypes were used: wild type (WT) strain 137C and two strains (H-3 and AK-9-9), which are highly resistant to radiation based on survival studies. Based on a micro-colony assay, the strains could be arranged according to their single-dose resistance to zeocin as follows: AK-9-9 > H-3 > 137C.

Impact of mutual health organizations: evidence from West Africa.

Mutual health organizations (MHOs) are voluntary membership organizations providing health insurance services to their members. MHOs aim to increase access to health care by reducing out-of-pocket payments faced by households. We used multiple regression analysis of household survey data from Ghana, Mali and Senegal to investigate the determinants of enrollment in MHOs, and the impact of MHO membership on use of health care services and on out-of-pocket health care expenditures for outpatient care and hospitalization.

Induction of DNA double-strand breaks by zeocin in Chlamydomonas reinhardtii and the role of increased DNA double-strand breaks rejoining in the formation of an adaptive response.

This study aimed to test the potential of the radiomimetic chemical zeocin to induce DNA double-strand breaks (DSB) and "adaptive response" (AR) in Chlamydomonas reinhardtii strain CW15 as a model system. The AR was measured as cell survival using a micro-colony assay, and by changes in rejoining of DSB DNA. The level of induced DSB was measured by constant field gel electrophoresis based on incorporation of cells into agarose blocks before cell lysis.

Genetic variability in Daphnia magna and ecotoxicological evaluation.

The fresh water crustacean Daphnia magna is widely used as a test organism in aquatic toxicology to assess the adverse effects of individual substances or complex mixtures, e.g. industrial wastewaters.

[The potential of 1,1'-hexamethylenebis [3-(3,5-dichloro-4-pyridyl)] urea to modify genotoxic actions of chemical mutagens in various test-systems].

The main tasks of this investigation were to investigate the potential genotoxic effect of 1,1'-hexamethylenebis [3-(3,5-dichloro-4-pyridyl)] urea and to analyze its capacity to induce adaptive response (AR) against chemical mutagens in various test-systems. Microbiological, cytogenetical and biochemical end-points were used. The sensitivity of test systems can be arranged as followed: human lymphocyte cultures > Chlamydomonas reinhardtii > Hordeum vulgare.

Acceleration of DNA-double strand rejoining during the adaptive response of Chlamydomonas reinhardtii.

Newly developed constant-field low voltage electrophoresis (adapted for algae cells by us) was applied to quantify the induction and repair of nuclear DNA double-strand breaks, by measuring the movement of DNA out of the starting wells into the electrophoresis gel using a UV-gel scan and computer analysis of DNA-ethidium bromide fluorescense (Syngene; Gene tools). A cell-wall-less mutant strain of Chlamydomonas reinhardtii (CW15) was used; the DNA and proteins are easily accessible because of the lack of an outer cell wall. Our results showed that giving a small priming dose (50 Gy) led to a small acceleration of dsb rejoining.

Some aspects of the plant radioresistance.

Mutant strains of unicellular green algae--Chlorella and Chlamydomonas which differ in their radioresistance have been investigated at different levels: cellular, molecular, biochemical and ultrastructural. It is obtained that several futures are typical for investigated strains. There are several features typical for radioresistant mutant strains investigated by us: in some cases a relationship was found between radioresistance and ssb-DNA repair efficiency; a high level of SH-groups; SOD; pigments content, especially carotenoids and chlorophyll a; a lower level of Pro content; a stability of the ultrastructural cell components or/and of the presence and structure of the cell envelope.

[Genotoxic effect of cadmium chloride in various test-systems].

Many industrial regions of Bulgaria are contaminated with cadmium. Induction of various genetic damages by four concentrations of cadmium chloride was studied in various test systems. None of the tested concentrations induced gene mutations in Salmonella typhimurium.

Repair of radiation induced DNA damages in unicellular green algae.

Two cell repair systems--photoreactivation and repair of single-strand DNA breaks have been studied using unicellular green algae as a test-system. Effects of the genotype and the intensity of pico/second UV-laser irradiation on the degree of the photoreactivation have been investigated. It has been shown that the lower intensity (I = 8.