Living in the paddies: a social science perspective on how inland valley irrigated rice cultivation affects malaria in Northern Côte d'Ivoire

The potential impact of irrigated agriculture on water‐related vector‐borne diseases has been an increasing source of concern for researchers from the bio‐medical sector. While most research on the potential impacts of irrigation on the health of local populations focuses on vector densities, levels of exposures, health services and technologies (prophylaxis, mosquito nets), we argue that it is essential to enlarge the scope of investigation and consider the complex mechanisms by which factors such as agriculture‐generated changes in ecosystems, gender repositioning in the family organization as a result of access to new crops, and production activities combine together in increasing disease risks and producing new scenarios in the management of disease. This paper presents the results of an investigation of how transformations induced on the local society by the intensification of inland valley irrigated rice cultivation influence malaria health care systems and modulate risks to the health of local populations, within well‐defined geographical boundaries in northern Côte d'Ivoire. Our results indicate that socio‐economic transformations and gender repositioning induced, or facilitated, by the intensification of inland valley irrigated rice cultivation lead to a reduction of the capacity of women to manage disease episodes, contributing therefore to increase malaria incidence among farming populations.     

Cost-utility analysis of patient care in children with meningeal signs

OBJECTIVES: We designed a model of diagnostic and therapeutic interventions applied in children with meningeal signs. Using this model, we determined in a cost-utility analysis the consequences for society of different diagnostic strategies in terms of quality-adjusted life-years (QALYs) and costs. METHODS: Data were used from 360 children (0.1-15 years) visiting the pediatric emergency department of the Sophia Children's Hospital Rotterdam, The Netherlands (1988-98) with meningeal signs. Model inputs included probabilities of meningitis and adverse outcome, QALYs for years lived with long-term sequelae, and costs of tests and treatments. Mean outcome measures were costs and effects of diagnostic and therapeutic interventions in children suspected of bacterial meningitis, key determinants of the model outcomes, and evaluation of alternative diagnostic strategies and two vaccination programs in an analysis. RESULTS: The population comprised 99 children with bacterial meningitis (adverse outcome in 10), 36 with serious other bacterial infections, and 225 with self-limiting diseases. Key determinants were the risk of bacterial meningitis or sequelae, costs of treatment, and long-term morbidity. Minimizing lumbar punctures and empirical treatments using a diagnostic decision rule, without missing a single case of meningitis, was a dominant strategy to actual practice. Vaccination strategies of Streptococcus pneumoniae and Neisseria meningitidis resulted in our model in incremental cost-utility ratios of 401,965 Euro dollar ([symbol: see text])/QALY and [symbol: see text]22,635/QALY, respectively. CONCLUSIONS: Costs of long-term morbidity of bacterial meningitis largely outweigh diagnostic and treatment costs. Modeling interventions in children at risk of bacterial meningitis should include long-term consequences in terms of costs and QALYs.     

Coherent infrared emission from myoglobin crystals: an electric field measurement

We introduce coherent infrared emission interferometry as a chi(2) vibrational spectroscopy technique and apply it to studying the initial dynamics upon photoactivation of myoglobin (Mb). By impulsive excitation (using 11-fs pulses) of a Mb crystal, vibrations that couple to the optical excitation are set in motion coherently. Because of the order in the crystal lattice the coherent oscillations of the different proteins in the crystal that are associated with charge motions give rise to a macroscopic burst of directional multi-teraHertz radiation. This radiation can be detected in a phase-sensitive way by heterodyning with a broad-band reference field. In this way both amplitude and phase of the different vibrations can be obtained. We detected radiation in the 1,000-1,500 cm(-1) frequency region, which contains modes sensitive to the structure of the heme macrocycle, as well as peripheral protein modes. Both in carbonmonoxy-Mb and aquomet-Mb we observed emission from six modes, which were assigned to heme vibrations. The phase factors of the modes contributing to the protein electric field show a remarkable consistency, taking on values that indicate that the dipoles are created "emitting" at t = 0, as one would expect for impulsively activated modes. The few deviations from this behavior in Mb-CO we propose are the result of these modes being sensitive to the photodissociation process and severely disrupted by it.     

Glutathathione synthetase of bovine lens: anomalies of the enzyme-catalyzed formation of ophthalmic acid

The activity of glutathione synthetase from bovine lens was examined as a functions of the concentration of L-gamma-glutamyl-L-alpha-aminobutyrate, the dipeptide substrate required in the formation of ophthalmic acid. Several significant anomalies of the glutathione synthetase-catalyzed formation of ophthalmic acid were found. Curvilinearity of double reciprocal plots occurred with this substrate; this curvilinearity shows substrate activation of the reaction which is likely a result of negative cooperativity. Both ATP4- and, to a lesser extent Mg2+ inhibited the reaction, whereas MgATP2- is the substrate; maximum activity occurred with 2 mM Mg2+ in excess of the concentration of added ATP. This investigation shows that it is necessary to establish a defined set of conditions for reporting enzyme activity and that the usual practice of using very large concentrations of Mg2+ relative to ATP, and 5- to 20-fold excess of the dipeptide will give less than optimum activity. The unit of enzyme activity is suggested to be that activity in ml using 2 mM ATP, 4 mM Mg2+, 30 mM glycine and 15 mM L-gamma-glutamyl-alpha-aminobutyrate, which results in the formation of 1 nmole/minute of ADP or P(i). In this study, 5'-AMP was for the first time, shown to be an inhibitor of the reaction with a K(i) of 0.9 mM.     

Disaster-related posttraumatic stress symptoms and sustained attention: evaluation of depressive symptomatology and sleep disturbances as mediators

Research about attentional functioning following trauma has almost exclusively been performed in patient populations with combat-related posttraumatic stress disorder (PTSD). In this study the relationship between sustained attention and PTSD symptoms was examined in a community sample of survivors of a major disaster using the Paced Auditory Serial Addition Task (PASAT) and the Self-Rating Scale for PTSD (SRS-PTSD) 2-3 years postdisaster. Analyses revealed low but significant partial correlations between PTSD symptoms and the least difficult subtests, ruling out the effects of age, education, depressive symptomatology, and sleep disturbances. These results demonstrate that PTSD symptoms link to attentional dysfunction 2-3 years postdisaster.     

Combined training of GPs and practice-assistants on peripheral arterial disease: positive effects after six months

OBJECTIVES: To improve the use of the ankle-brachial index (ABI) measurement, and management of patients with peripheral arterial disease (PAD) a combined training, targeting GPs and practice assistants (PAs) was developed. To measure the effect of the combined training on the management of patients with PAD, a cross-sectional study was performed. METHODS: Fifty consecutive patients referred by GPs to a vascular surgery out-patient clinic were analysed. Six months after the training an additional fifty patients were included. In all patients the ABI measurement, risk factor management, and treatment as performed by the GP, prior to referral, were analysed. RESULTS: The measurement of the ABI significantly increased from 10% before the training to 53% after the training (GPs with training: 83%, GPs without training: 35%; P: 0.001). The referral of patients with actual PAD significantly increased from 32% before the training to 70% after the training (GPs with training: 83%, GPs without training: 59%; P: 0.05). The presence and treatment of risk factors did not differ between the groups. CONCLUSIONS: Within the limitations of a before and after study the combined training of GPs and PAs appears to be an effective method to increase ABI measurements and significantly improve adequate diagnostics.     

Therapeutic vaccination against chronic hepatitis B virus infection

Chronic liver disease and hepatocellular carcinoma associated with chronic hepatitis B virus (HBV) infection are among the most serious human health problems in highly endemic regions. Despite the existence for many years of effective vaccines against HBV, more than 370 million people remain persistently infected with HBV today. Currently available therapies fail to provide long-term control of viral replication in most patients. Viral persistence has been associated with a defect in the development of HBV-specific cell-mediated immunity. Strategies to boost or to broaden the weak virus-specific T-cell response of patients with chronic hepatitis B have been proposed as a means of terminating this persistent infection. The immunogenicity of HBV envelope- or capsid-based vaccines, new formulations for recombinant vaccines as well as DNA-based vaccines are currently under investigation in clinical trials. Although improvements are still required, vaccination would be the therapeutic procedure with the lowest cost and the potentially greatest benefit.