The small-molecule kinase inhibitor ceritinib, unlike imatinib, causes a significant disturbance of lipid membrane integrity: A combined experimental and MD study

Ceritinib and imatinib are small-molecule protein kinase inhibitors which are applied as therapeutic agents against various diseases. The fundamentals of their clinical use, i.e. their pharmacokinetics as well as the mechanisms of the inhibition of the respective kinases, are relatively well studied. However, the interaction of the drugs with membranes, which can be a possible cause of side effects, has hardly been investigated so far. Therefore, we have characterized the interaction of both drugs with lipid membranes consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in the absence and in the presence of cholesterol. For determining the membrane impact of both drugs on a molecular level, different experimental (NMR, ESR, fluorescence) and theoretical (MD simulations) approaches were applied. The data show that ceritinib, in contrast to imatinib, interacts more effectively with membranes significantly affecting various physico-chemical membrane parameters like membrane order and transmembrane permeation of polar solutes. The pronounced membrane impact of ceritinib can be explained by a strong affinity of the drug towards POPC which competes with the POPC-cholesterol interaction by that attenuating the ordering effect of cholesterol. The data are relevant for understanding putative toxic and cytotoxic side effects of these drugs such as the triggering of cell lysis or apoptosis.

Effects of the RNA-Polymerase Inhibitors Remdesivir and Favipiravir on the Structure of Lipid Bilayers-An MD Study

The structure and dynamics of membranes are crucial to ensure the proper functioning of cells. There are some compounds used in therapeutics that show nonspecific interactions with membranes in addition to their specific molecular target. Among them, two compounds recently used in therapeutics against COVID-19, remdesivir and favipiravir, were subjected to molecular dynamics simulation assays. In these, we demonstrated that the compounds can spontaneously bind to model lipid membranes in the presence or absence of cholesterol. These findings correlate with the corresponding experimental results recently reported by our group. In conclusion, insertion of the compounds into the membrane is observed, with a mean position close to the phospholipid head groups.

Drug-Membrane Interactions: Effects of Virus-Specific RNA-Dependent RNA Polymerase Inhibitors Remdesivir and Favipiravir on the Structure of Lipid Bilayers

The two RNA-dependent RNA polymerase inhibitors remdesivir and favipiravir were originally developed and approved as broad-spectrum antiviral drugs for the treatment of harmful viral infections such as Ebola and influenza. With the outbreak of the global SARS-CoV-2 pandemic, the two drugs were repurposed for the treatment of COVID-19 patients. Clinical studies suggested that the efficacy of the drugs is enhanced in the case of an early or even prophylactic application. Because the contact between drug molecules and the plasma membrane is essential for a successful permeation process of the substances and therefore for their intracellular efficiency, drug-induced effects on the membrane structure are likely and have already been shown for other substances. We investigated the impact of remdesivir and favipiravir on lipid bilayers in model and cell membranes via several biophysical approaches. The measurements revealed that the embedding of remdesivir molecules in the lipid bilayer results in a disturbance of the membrane structure of the tested phospholipid vesicles. Nevertheless, in a cell-based assay, the presence of remdesivir induced only weak hemolysis of the treated erythrocytes. In contrast, no experimental indication for an effect on the structure and integrity of the membrane was detected in the case of favipiravir. Regarding potential prophylactic or accompanying use of the drugs in the therapy of COVID-19, the physiologically relevant impacts associated with the drug-induced structural modifications of the membrane might be important to understand side effects and/or low effectivities.

Binding of the small-molecule kinase inhibitor ruxolitinib to membranes does not disturb membrane integrity

Ruxolitinib is a small-molecule protein kinase inhibitor, which is used as a therapeutic agent against several diseases. Due to its anti-inflammatory impact, ruxolitinib has also been considered recently for usage in the treatment of Covid-19. While the specific effects of ruxolitinib on Janus kinases (JAK) is comparatively well investigated, its (unspecific) impact on membranes has not been studied in detail so far. Therefore, we characterized the interaction of this drug with lipid membranes employing different biophysical approaches. Ruxolitinib incorporates into the glycerol region of lipid membranes causing an increase in disorder of the lipid chains. This binding, however, has only marginal influence on the structure and integrity of membranes as found by leakage and permeation assays.

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The drug ruxolitinib binds to lipid membranes.

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Ruxolitinib intercalates into the glycerol region of the bilayer.

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The membrane binding of ruxolitinib causes an increased disorder of the lipid chains.

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The membrane binding of ruxolitinib has no influence on the membrane integrity.

Membrane Interaction of Ibuprofen with Cholesterol-Containing Lipid Membranes

Deciphering the membrane interaction of drug molecules is important for improving drug delivery, cellular uptake, and the understanding of side effects of a given drug molecule. For the anti-inflammatory drug ibuprofen, several studies reported contradictory results regarding the impact of ibuprofen on cholesterol-containing lipid membranes. Here, we investigated membrane localization and orientation as well as the influence of ibuprofen on membrane properties in POPC/cholesterol bilayers using solid-state NMR spectroscopy and other biophysical assays. The presence of ibuprofen disturbs the molecular order of phospholipids as shown by alterations of the ²H and ³¹P-NMR spectra of the lipids, but does not lead to an increased membrane permeability or changes of the phase state of the bilayer. ¹H MAS NOESY NMR results demonstrate that ibuprofen adopts a mean position in the upper chain/glycerol region of the POPC membrane, oriented with its polar carbonyl group towards the aqueous phase. This membrane position is only marginally altered in the presence of cholesterol. A previously reported result that ibuprofen is expelled from the membrane interface in cholesterol-containing DMPC bilayers could not be confirmed.

Interaction of the small-molecule kinase inhibitors tofacitinib and lapatinib with membranes

Lapatinib and tofacitinib are small-molecule kinase inhibitors approved for the treatment of advanced or metastatic breast cancer and rheumatoid arthritis, respectively. So far, the mechanisms which are responsible for their activities are not entirely understood. Here, we focus on the interaction of these drug molecules with phospholipid membranes, which has not yet been investigated before in molecular detail. Owing to their lipophilic characteristics, quantitatively reflected by large differences of the partition equilibrium between water and octanol phases (expressed by logP values), rather drastic differences in the membrane interaction of both molecules have to be expected. Applying experimental (nuclear magnetic resonance, fluorescence and ESR spectroscopy) and theoretical (molecular dynamics simulations) approaches, we found that lapatinib and tofacitinib bind to lipid membranes and insert into the lipid-water interface of the bilayer. For lapatinib, a deeper embedding into the membrane bilayer was observed than for tofacitinib implying different impacts of the molecules on the bilayer structure. While for tofacitinib, no influence to the membrane structure was found, lapatinib causes a membrane disturbance, as concluded from an increased permeability of the membrane for polar molecules. These data may contribute to a better understanding of the cellular uptake mechanism(s) and the side effects of the drugs.

Dual Photoisomerization on Distinct Potential Energy Surfaces in a UV-Absorbing Rhodopsin

UV-absorbing rhodopsins are essential for UV vision and sensing in all kingdoms of life. Unlike the well-known visible-absorbing rhodopsins, which bind a protonated retinal Schiff base for light absorption, UV-absorbing rhodopsins bind an unprotonated retinal Schiff base. Thus far, the photoreaction dynamics and mechanisms of UV-absorbing rhodopsins have remained essentially unknown. Here, we report the complete excited- and ground-state dynamics of the UV form of histidine kinase rhodopsin 1 (HKR1) from eukaryotic algae, using femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy, covering time scales from femtoseconds to milliseconds. We found that energy-level ordering is inverted with respect to visible-absorbing rhodopsins, with an optically forbidden low-lying S₁ excited state that has Ag^– symmetry and a higher-lying UV-absorbing S₂ state of Bu⁺ symmetry. UV-photoexcitation to the S₂ state elicits a unique dual-isomerization reaction: first, C13=C14 cis–trans isomerization occurs during S₂–S₁ evolution in <100 fs. This very fast reaction features the remarkable property that the newly formed isomer appears in the excited state rather than in the ground state. Second, C15=N16 anti–syn isomerization occurs on the S₁–S₀ evolution to the ground state in 4.8 ps. We detected two ground-state unprotonated retinal photoproducts, 13-trans/15-anti (all-trans) and 13-cis/15-syn, after relaxation to the ground state. These isomers become protonated in 58 μs and 3.2 ms, respectively, resulting in formation of the blue-absorbing form of HKR1. Our results constitute a benchmark of UV-induced photochemistry of animal and microbial rhodopsins.

MerMAIDs: a family of metagenomically discovered marine anion-conducting and intensely desensitizing channelrhodopsins

Channelrhodopsins (ChRs) are algal light-gated ion channels widely used as optogenetic tools for manipulating neuronal activity. ChRs desensitize under continuous bright-light illumination, resulting in a significant decline of photocurrents. Here we describe a metagenomically identified family of phylogenetically distinct anion-conducting ChRs (designated MerMAIDs). MerMAIDs almost completely desensitize during continuous illumination due to accumulation of a late non-conducting photointermediate that disrupts the ion permeation pathway. MerMAID desensitization can be fully explained by a single photocycle in which a long-lived desensitized state follows the short-lived conducting state. A conserved cysteine is the critical factor in desensitization, as its mutation results in recovery of large stationary photocurrents. The rapid desensitization of MerMAIDs enables their use as optogenetic silencers for transient suppression of individual action potentials without affecting subsequent spiking during continuous illumination. Our results could facilitate the development of optogenetic tools from metagenomic databases and enhance general understanding of ChR function.

Channelrhodopsins (ChRs) are algal light-gated ion channels used as optogenetic tools for manipulating neuronal activity. Here authors present a metagenomically identified family of phylogenetically distinct anion-conducting ChRs (MerMAIDs) which desensitize during continuous illumination due to accumulation of a non-conducting photointermediate.

Photoreactions of the Histidine Kinase Rhodopsin Ot-HKR from the Marine Picoalga Ostreococcus tauri

The tiny picoalga, Ostreococcus tauri, originating from the Thau Lagoon is a member of the marine phytoplankton. Because of its highly reduced genome and small cell size, while retaining the fundamental requirements of a eukaryotic photosynthetic cell, it became a popular model organism for studying photosynthesis or circadian clock-related processes. We analyzed the spectroscopic properties of the photoreceptor domain of the histidine kinase rhodopsin Ot-HKR that is suggested to be involved in the light-induced entrainment of the Ostreococcus circadian clock. We found that the rhodopsin, Ot-Rh, dark state absorbs maximally at 505 nm. Exposure to green-orange light led to the accumulation of a blue-shifted M-state-like absorbance form with a deprotonated Schiff base. This Ot-Rh P400 state had an unusually long lifetime of several minutes. A second long-living photoproduct with a red-shifted absorbance, P560, accumulated upon illumination with blue/UVA light. The resulting photochromicity of the rhodopsin is expected to be advantageous to its function as a molecular control element of the signal transducing HKR domains. The light intensity and the ratio of blue vs green light are reflected by the ratio of rhodopsin molecules in the long-living absorbance forms. Furthermore, dark-state absorbance and the photocycle kinetics vary with the salt content of the environment substantially. This observation is attributed to anion binding in the dark state and a transient anion release during the photocycle, indicating that the salinity affects the photoinduced processes.

The two parallel photocycles of the Chlamydomonas sensory photoreceptor histidine kinase rhodopsin 1

Histidine kinase rhodopsins (HKRs) belong to a class of unexplored sensory photoreceptors that share a similar modular architecture. The light sensing rhodopsin domain is covalently linked to signal-transducing modules and in some cases to a C-terminal guanylyl-cyclase effector. In spite of their wide distribution in unicellular organisms, very little is known about their physiological role and mechanistic functioning. We investigated the photochemical properties of the recombinant rhodopsin-fragment of Cr-HKR1 originating from Chlamydomonas reinhardtii. Our spectroscopic studies revealed an unusual thermal stability of the photoproducts with the deprotonated retinal Schiff base (RSB). Upon UV-irradiation these Rh-UV states with maximal absorbance in the UVA-region (Rh-UV) photochemically convert to stable blue light absorbing rhodopsin (Rh-Bl) with protonated chromophore. The heterogeneity of the sample is based on two parallel photocycles with the chromophore in C₁₅=N-syn- or -anti-configuration. This report represents an attempt to decipher the underlying reaction schemes and interconversions of the two coexisting photocycles.

Predictive Modeling of Tacrolimus Dose Requirement Based on High-Throughput Genetic Screening

Any biochemical reaction underlying drug metabolism depends on individual gene-drug interactions and on groups of genes interacting together. Based on a high-throughput genetic approach, we sought to identify a set of covariant single-nucleotide polymorphisms predictive of interindividual tacrolimus (Tac) dose requirement variability. Tac blood concentrations (Tac C₀ ) of 229 kidney transplant recipients were repeatedly monitored after transplantation over 3 mo. Given the high dimension of the genomic data in comparison to the low number of observations and the high multicolinearity among the variables (gene variants), we developed an original predictive approach that integrates an ensemble variable-selection strategy to reinforce the stability of the variable-selection process and multivariate modeling. Our predictive models explained up to 70% of total variability in Tac C₀ per dose with a maximum of 44 gene variants (p-value <0.001 with a permutation test). These models included molecular networks of drug metabolism with oxidoreductase activities and the multidrug-resistant ABCC8 transporter, which was found in the most stringent model. Finally, we identified an intronic variant of the gene encoding SLC28A3, a drug transporter, as a key gene involved in Tac metabolism, and we confirmed it in an independent validation cohort.

Light-Dark Adaptation of Channelrhodopsin Involves Photoconversion between the all-trans and 13-cis Retinal Isomers

Channelrhodopsins (ChR) are light-gated ion channels of green algae that are widely used to probe the function of neuronal cells with light. Most ChRs show a substantial reduction in photocurrents during illumination, a process named "light adaptation". The main objective of this spectroscopic study was to elucidate the molecular processes associated with light-dark adaptation. Here we show by liquid and solid-state nuclear magnetic resonance spectroscopy that the retinal chromophore of fully dark-adapted ChR is exclusively in an all-trans configuration. Resonance Raman (RR) spectroscopy, however, revealed that already low light intensities establish a photostationary equilibrium between all-trans,15-anti and 13-cis,15-syn configurations at a ratio of 3:1. The underlying photoreactions involve simultaneous isomerization of the C(13)═C(14) and C(15)═N bonds. Both isomers of this DAapp state may run through photoinduced reaction cycles initiated by photoisomerization of only the C(13)═C(14) bond. RR spectroscopic experiments further demonstrated that photoinduced conversion of the apparent dark-adapted (DAapp) state to the photocycle intermediates P500 and P390 is distinctly more efficient for the all-trans isomer than for the 13-cis isomer, possibly because of different chromophore-water interactions. Our data demonstrating two complementary photocycles of the DAapp isomers are fully consistent with the existence of two conducting states that vary in quantitative relation during light-dark adaptation, as suggested previously by electrical measurements.

Bistable retinal schiff base photodynamics of histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii

The photodynamics of the recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii was studied by absorption and fluorescence spectroscopy. The retinal cofactor of HKR1 exists in two Schiff base forms RetA and RetB. RetA is the deprotonated 13-cis-retinal Schiff base (RSB) absorbing in the UVA spectral region. RetB is the protonated all-trans RSB absorbing in the blue spectral region. Blue light exposure converts RetB fully to RetA. UVA light exposure converts RetA to RetB and RetB to RetA giving a mixture determined by their absorption cross sections and their conversion efficiencies. The quantum efficiencies of conversion of RetA to RetB and RetB to RetA were determined to be 0.096 ± 0.005 and 0.405 ± 0.01 respectively. In the dark thermal equilibration between RetA and RetB with dominant RetA content occurred with a time constant of about 3 days at room temperature. The fluorescence emission behavior of RetA and RetB was studied, and fluorescence quantum yields of ϕ(F) (RetA) = 0.00117 and ϕ(F) (RetB) = 9.4 × 10(-5) were determined. Reaction coordinate schemes of the photodynamics are developed.

A photochromic histidine kinase rhodopsin (HKR1) that is bimodally switched by ultraviolet and blue light

Rhodopsins are light-activated chromoproteins that mediate signaling processes via transducer proteins or promote active or passive ion transport as ion pumps or directly light-activated channels. Here, we provide spectroscopic characterization of a rhodopsin from the Chlamydomonas eyespot. It belongs to a recently discovered but so far uncharacterized family of histidine kinase rhodopsins (HKRs). These are modular proteins consisting of rhodopsin, a histidine kinase, a response regulator, and in some cases an effector domain such as an adenylyl or guanylyl cyclase, all encoded in a single protein as a two-component system. The recombinant rhodopsin fragment, Rh, of HKR1 is a UVA receptor (λ(max) = 380 nm) that is photoconverted by UV light into a stable blue light-absorbing meta state Rh-Bl (λ(max) = 490 nm). Rh-Bl is converted back to Rh-UV by blue light. Raman spectroscopy revealed that the Rh-UV chromophore is in an unusual 13-cis,15-anti configuration, which explains why the chromophore is deprotonated. The excited state lifetime of Rh-UV is exceptionally stable, probably caused by a relatively unpolar retinal binding pocket, converting into the photoproduct within about 100 ps, whereas the blue form reacts 100 times faster. We propose that the photochromic HKR1 plays a role in the adaptation of behavioral responses in the presence of UVA light.

Modelling tritium flux from water to atmosphere: application to the Loire River

Tritium (³H or T) is one of the major radionuclides released by nuclear power plants (NPP) into rivers. However, tritiated water (HTO) flux from water to air is seldom considered when assessing health effects of such releases. The aim of this paper is to present the result of a research program, called LORA, conducted on the Loire River (France). To improve our understanding of HTO flux from surface water to air, three field campaigns were organised during the NPP's radioactive releases to measure simultaneously the activity concentrations in air on the riverbank, using an innovative system, and in river water. The measurements showed that during radioactive releases, water vapour was enriched in ³H. These results were used to calibrate exchange velocities. The average of these estimated exchange velocities was more than one order of magnitude higher than those calculated in the literature from indoor experiments. The variability of these values was also larger, showing that outdoor studies cover a wide range of conditions influencing HTO flux. No correlation was observed between exchanges velocities and meteorological conditions. However, there was a significant difference between day and night with a higher value observed during the day. Two approaches used to calculate HTO evaporation from water (i.e. the approach based on water evaporation and the approach considering that HTO follows its own concentration gradient) were included in a hydrodynamic model, which was used to evaluate HTO air activity along the Loire River. In conclusion, only the approach considering that HTO follows its own gradient led to a good agreement between measurements and predictions. A one-year simulation was done to estimate the contribution of this process to the dose. Its contribution can be considered as negligible in this case compared to the other pathways such as ingestion of water or foodstuffs.

Cervical screening: Perceptions and barriers to uptake among Somali women in Camden

OBJECTIVES

To explore barriers to, and ways to improve, uptake of cervical screening among Somali women in Camden, London.

STUDY DESIGN

A qualitative research study using focus group discussions and in-depth interviews.

METHODS

A qualitative study (comprising seven focus groups and eight in-depth interviews) was conducted with 50 first-generation Somali women aged 25-64 years. Both the groups and the interviews explored participants' understanding of the purpose of cervical screening, and the various risk factors for cervical cancer, as well as their opinions on barriers to screening and suggestions for overcoming those barriers.

RESULTS

Knowledge about the purpose of cervical screening was limited among Somali women. There was also a lack of understanding of risk factors for cervical cancer, and many of the women held fatalistic attitudes, associated with the idea of 'God's will', about this cancer and other aspects of health. Another culturally specific barrier was embarrassment associated with female circumcision, i.e. female genital mutilation. Other barriers suggested by the participants were: lack of knowledge about the need for cervical screening, practical problems such as appointment times and childcare needs, language difficulties, fear of the test and negative past experiences. Possible solutions suggested by the participants included the provision of education and information about cervical screening in the Somali language by Somali community workers. They also suggested that healthcare staff should be trained about Somali culture, particularly regarding female circumcision, and that general practitioners should more proactively encourage Somali women to attend screening.

CONCLUSIONS

Language difficulties and specific cultural issues are key barriers to first-generation Somali women attending cervical screening. Providing education and information orally, as well as improving access to a more culturally appropriate screening service, could lead to improved uptake among this group.

A dynamic model for assessing radiological consequences of tritium routinely released in rivers. Application to the Loire River

A dynamic model for assessing the transfer of tritium in a food chain was applied to the Loire River, where 14 nuclear power plants situated on five different sites operate. The model considers several potential exposure pathways in the aquatic and terrestrial ecosystems: transfer of tritium through the aquatic food chain (especially fish); use of river water for agricultural purposes (irrigation) and transfer of radionuclides through the terrestrial food chain (vegetables, meat, milk); subsequent internal exposure of humans due to ingestion of contaminated foodstuffs. For biological environmental compartments, the transfer of tritium to organic matter (i.e. OBT) was simulated. For each of the parameters introduced in this model, a probability density function, allowing further uncertainty and sensitivity analyses, was proposed. Uncertainty/sensitivity analyses were performed to determine a confidence interval for the mean annual dose to critical groups and to identify the parameters responsible for the uncertainty and subsequent research priorities.

A dynamic model for assessing radiological consequences of routine releases in the Loire river: parameterisation and uncertainty/sensitivity analysis

A dynamic model for assessing the transfer of several radionuclides ((58)Co, (60)Co, (110 m)Ag, (134)Cs, (137)Cs, (54)Mn and (131)I) in a food-chain was applied on the Loire river, where 14 nuclear power plants situated on five different sites operate. The model considers the following potential exposure pathways: (i) transfer of radionuclides through the aquatic food chain and the subsequent internal exposure of humans due to ingestion of contaminated water and/or fish; (ii) use of river water for agricultural purposes (irrigation), transfer of radionuclides through the terrestrial food chain and the subsequent internal exposure of humans due to ingestion of contaminated foodstuffs; (iii) internal exposure due to inhalation of dust originating from resuspension of contaminated soil particles; (iv) external exposure from radionuclides present in the river or deposited on the river sediments or the soil. For each of the parameters introduced in this model, a probability density function, allowing further uncertainty and sensitivity analysis, was proposed. Uncertainty/sensitivity analysis were performed to: (i) compare calculations to empirical data; (ii) determine a confidence interval for the mean annual dose to critical groups; and (iii) identify the parameters responsible for the uncertainty and subsequent research priorities.

Chronic myelocytic leukemia in a juvenile rhesus macaque (Macaca mulatta)

Myeloid neoplasia has been studied extensively in human beings but has not been reported in macaques. A 2-year-old female rhesus macaque that was experimentally exposed to lead as a neonate, was noted to have immature circulating myelocytic cells, including 1% blasts, and normocytic normochromic anemia on a blood sample obtained for monthly health monitoring. The animal was treated with hydroxyurea, blood transfusion, and recombinant human erythropoietin to reduce the leukocytosis and correct the anemia. The disease had a relatively indolent course for 3 months, when it progressed to blast crisis. After the onset of blast crisis, the animal was euthanized because of bleeding problems, anemia, and a progressive decline in her health. The animal was negative by serology, polymerase chain reaction (PCR) assays, and/or culture for simian retrovirus (SRV), simian T-lymphotropic virus type I (STLV-I), and simian immunodeficiency virus (SIV). PCR assay for the bcr-ABL chromosomal translocation using primers made for the human gene was negative. Serology for Epstein-Barr virus (EBV)-like viruses was positive for IgG directed against the viral nucleocapsid antigen, but epidemiologic factors make it unlikely that the leukemia was associated with EBV-induced viral transformation. Lead exposure has been associated with neoplasia in human beings, and the possible role of neonatal lead exposure in hematologic neoplasias deserves further scrutiny.

Mobilizing demand for contraception in rural Gambia

A community trial was conducted in rural Gambia in order to determine whether a community-based intervention designed to mobilize latent demand for contraception would increase use of modern contraceptives, even in the absence of improved availability of family planning services. Analysis of trial data indicates that the demand-mobilization intervention had a statistically significant positive effect on nonusers' adoption of modern contraception and that coterminous implementation of an intervention designed to improve access to services offered no additional benefit. The program component found to have the greatest impact was the "kabilo approach," in which village women provide basic health and family planning counseling to other women in their extended families. These results suggest that the principal barriers to increased contraceptive use in rural Gambia are psychosocial and that these barriers can be overcome through village-based interventions designed to provide socially appropriate counseling to potential contraceptive users.

Safe motherhood intervention studies in Africa: a review

OBJECTIVE

To review the findings of safe motherhood intervention studies conducted in African settings.

DATA SOURCES

Published literature regarding interventions designed to reduce maternal mortality in African settings.

STUDY SELECTION

Studies conducted in sub-Saharan Africa to assess the effects of interventions designed to reduce maternal mortality.

DATA EXTRACTION

Search of Medline database for the years 1988 to 1998 with additional manual search of references cited in Medline-referenced studies.

DATA SYNTHESIS

Few of the 34 intervention studies identified used a double-blind, randomized controlled trial design (4/34), or outcome measures directly related to maternal mortality or maternal health (7/34). Six of the studies produced reasonably convincing evidence of a positive effect on maternal health outcomes. Of these, three showed that changes in delivery practices brought about improved maternal outcomes, two found that a combined intervention consisting of upgrading of emergency obstetric services and community education increased the number of major obstetric complications treated, and one showed that a range of improvements in hospital equipment and management reduced facility-based maternal mortality ratios. No study sought to reduce maternal mortality associated with unsafe termination of pregnancy.

CONCLUSIONS

More than a decade after the launching of the Safe Motherhood Initiative, there exists little evidence regarding which interventions will reduce maternal mortality levels in African settings. Intervention studies conducted in Africa have identified several low-tech improvements in emergency obstetric services which improve maternal outcomes and deserve replication and testing in a variety of settings. Further operational research should be conducted to identify and test other promising safe motherhood interventions, in particular interventions designed to reduce the important proportion of maternal mortality associated with unsafe termination of pregnancy.

Succimer and the urinary excretion of essential elements in a primate model of childhood lead exposure

Succimer is considered to be a safe and effective treatment for lead (Pb) poisoning, since it reduces body Pb levels without an apparent diuresis of other essential elements. However, while existing clinical data indicate that succimer does not significantly increase the excretion of non-target elements, those studies have also reported a wide range of outcomes. Therefore, we investigated whether succimer treatment measurably increased the urinary excretion of essential elements in a primate model of childhood Pb exposure. Infant rhesus monkeys (Macaca mulatta) were exposed to Pb from birth through one year of age, and presented blood Pb levels of approximately 40-50 microg/dL at the start of treatment. Subsequently, they were treated with succimer (30 mg/kg/day x 5 days followed by 20 mg/kg/day x 14 days, n = 15) or vehicle (n = 14) for 19 days. Complete urine samples were collected over the first 5 days of treatment, and were analyzed for levels of calcium (Ca), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese (Mn), nickel (Ni), and zinc (Zn), using trace metal-clean techniques and magnetic sector-ICP-MS. Succimer treatment significantly (p < 0.05) reduced blood Pb levels when compared to the vehicle group over the treatment period, and concomitantly produced a significant >4-fold increase in urinary Pb excretion. Succimer treatment also significantly (p < 0.05, multivariate ANOVA) increased the urinary excretion of essential elements, but only when the cumulative total excretion over treatment days 1-5 for all elements were considered. None of these relative increases reached statistical significance for any particular element x day, although increases in Zn (day 3) excretion were only marginally non-significant (0.1 > p > 0.05). Multivariate analyses of a subset of elements (Cu, Fe, Mn, Zn) similarly indicated no significant effect of succimer treatment overall, although the urinary excretion of Mn was significantly increased on day 3 of treatment. Collectively, these data indicate that succimer does contribute to an increase in the urinary excretion of essential elements, although not significantly for any single element considered here. This may be important in Pb-exposed children, who can possess reduced trace element reserves due to nutritional deficiencies.

Can information technology help ward sisters become ward managers?

AIM

This paper describes an evaluation methodology that focuses on management decisions at the ward level in a hospital.

BACKGROUND

Successive governments in the 1990s have provided considerable funds to introduce decision support systems for ward management, but few have been evaluated rigorously. This paper reviews the approaches to systems' evaluation that have been developed.

METHODS

Measuring instruments were designed to define and measure management decisions and those organizational factors which affect decision making. The resulting difficulty index was validated in a before-and-after study of ward decision making.

FINDINGS

Changes in decision making, after the implementation of a decision support system, were found to relate to the identified organizational factors.

CONCLUSION

The evaluation methodology described in this paper showed that the potential benefits of a computerized management system would not be realized unless managers, doctors and nurses carried out an organizational review before implementation and then took joint ownership of the system.

Organizing community nursing: an exploratory study

The NHS in the 1990s places increasing emphasis on primary care and puts pressure on general practitioners (GPs) and community nurses to deliver a broad range of high quality care in the most cost-effective possible way. In attempting to achieve these objectives, the British National Health Service (NHS) and its individual health authorities have re-examined the available range of organizational choices and increasingly the tendency is to organize community nursing around the focal point of general practice. The authors' evaluation of six innovative 'pilot projects' showed the effects of different organizational choices with respect to basing, purchasing, provision and management of community nursing services. It was found that there are some advantages to focusing primary care on the GP; basing of nurses on the practice is particularly advantageous. There are, however, some very clear indications that the adoption by GPs of multiple, and sometimes conflicting, roles of manager, provider and purchaser of community nursing inhibits the development of fully integrated primary health care teams and can be detrimental to the nursing function. It is concluded that the NHS needs to explore other less GP-centred organizational configurations within primary care.

Cultural differences in functional ability among elderly people in Birmingham, England, and Glostrup, Denmark

The purpose of this article is to compare patterns of functional ability among four groups of elderly people with different cultural backgrounds. The data originates from (1) a study of 369 65 to 74 year old people in Birmingham, born in England, the West Indies, and Asia, and (2) a study of 734 rafter homogeneous 70 year old people in Glostrup, Denmark. In both surveys functional ability was measured by interviews about Physical and Instrumental Activities of Daily Living (PADL and IADL). With regard to PADL there were only a few differences between the four study populations, whereas larger differences were found in IADL. The general pattern was that the Glostrup population had better functional ability than the other study populations and that Asians had the poorest functional ability. The reasons for these differences may arise from different patterns of disease, variations in life style, and differing access to and response from social and health services in the four cultural groups.

Ethnic influence on health and dependency of elderly inner city residents

The objectives of the study were to assess and compare the social characteristics, prevalence of disease, health needs, dependency and use of health services by elderly people in the different ethnic groups living in an inner city. A prevalence study was conducted using a questionnaire administered to people aged 65 years and over living at home, selected from the registers of inner city general practices in West Birmingham. Contact was made with 736 individuals from the original sample of 1,450 names, and completed questionnaires were obtained from 669 individuals (297 men, 372 women). Respondents were divided by place of birth into four groups: UK, Asia, West Indies, and 'Other'. Outcome measures were demographic data, language, household composition, prevalence of disease and health problems, help with activities of daily living, and contact with and knowledge of community health services. We found that those born in the UK were likely to be older, female, unmarried and living alone. In the Asian group, only 15% spoke English and 59% lived in a household with more than three other people compared with 4% in both the UK and West Indian groups. Hypertension was more common in West Indians, arthritis in Asians and diabetes mellitus more common in both groups than in the UK group. Asians were more likely to complain of poor vision. The level of dependency was similar in all groups despite age differences. Contact with community health services was low among Asians who also had a low awareness of the availability of these services. The conclusions from the study were that the average age of elderly individuals in ethnic minority groups is less than that of the indigenous population, making direct comparison difficult. Nevertheless, they have a higher prevalence of age-related disease and a similar level of dependency. They are less well served by, and have little knowledge of the existence of, community health services. For older Asians, difficulty in communicating with English-speaking health personnel is a major barrier to effective health care. Access to health care by older people from ethnic minorities needs to be improved, and services developed in a more culturally sensitive manner.

Peripartum liver triglyceride and plasma metabolites in dairy cows

Nine pregnant, nonlactating cows were used to monitor liver triglycerides before and after parturition. Estimates were made of the contribution of depressed feed intake and parturition to plasma NEFA concentrations and development of fatty liver. Liver biopsies and plasma samples were obtained on d 19, 10, 5, 3, and 1 prior to calving and on d 1, 7, 14, and 21 after calving. Depression of DMI started on d 2 prior to calving and was 40% of DMI on d 3 prior to depression of feed intake. Elevation of plasma NEFA concentrations started prior to DMI depression, on d 5 before parturition. Liver triglyceride infiltration did not occur until the concentration of plasma NEFA was maximized on d 1 after calving. This result implicated the acute rise in NEFA at calving as a contributing factor to triglyceride accumulation in the liver. The increasing plasma glucose and decreasing plasma BHBA prior to calving may have reflected metabolic changes toward gluconeogenesis. Liver glycogen decreased 70% during the final 19 d prior to calving. Hepatic triglyceride infiltration (7.7% DM basis) on d 1 post-partum and duration of DMI depression prepartum were less severe than those observed in previous studies. Frequent liver biopsies did not affect DMI.

Working women in the sex industry and their perception of risk from HIV/AIDS

The present research project provided women who are normally marginalized by society with an opportunity to give their opinions on health matters that are directly related to their working and personal lives. Discussion groups were held with women working in saunas or massage parlors (the sex industry) to obtain their views on sexual health and the risk of infection from the human immunodeficiency virus. The sauna workers said they have less chance of becoming infected than women not working in the sex industry, because they are very careful about their activities in the sauna. The women were very concerned about their children and wanted information to give to their children rather than for themselves. Although these women used condoms at work, they said they were reluctant to use condoms in their social relationships because of the association with work.

Cloning and sequence analysis of a cDNA from human ovarian granulosa cells encoding the C-terminal part of human elongation factor 2

A cDNA clone, pHGR81, encoding 358 amino-acid residues of the C-terminal region of human elongation factor 2 (EF-2), was isolated from a human ovarian granulosa cell cDNA library. The deduced amino-acid sequence of pHGR81, when compared with the known identical amino-acid sequences of hamster as well as rat EF-2 revealed a substitution of a glutamine by an alanine residue in the partially determined human sequence. The 15 amino-acid-residue sequence comprising the histidine-715, supposed to be of importance for the biological function of EF-2, is preserved in human EF-2. The coding region of the cDNA insert of pHGR81 displays a homology of 87% to hamster and of 88% to rat EF-2 cDNA. In Northern-transfer analysis, pHGR81 specifically hybridizes with an mRNA species of 3.1 kb.