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Kim J. Brolin Ribacke Alex J. van Duinen Helena Nordenstedt Jonas H?ijer Ragnhild Molnes Torunn Wigum Froseth AP Koroma Elisabeth Darj H?kon Angel Bolkan AnnaMia Ekstr?m 《PloS one》2016,11(2)
Background
As Sierra Leone celebrates the end of the Ebola Virus Disease (EVD) outbreak, we can begin to fully grasp its impact on already weak health systems. The EVD outbreak in West Africa forced many hospitals to close down or reduce their activity, either to prevent nosocomial transmission or because of staff shortages. The aim of this study is to assess the potential impact of EVD on nationwide access to obstetric care in Sierra Leone.Methods and Findings
Community health officers collected weekly data between January 2014—May 2015 on in-hospital deliveries and caesarean sections (C-sections) from all open facilities (public, private for-profit and private non-profit sectors) offering emergency obstetrics in Sierra Leone. This was compared to official data of EVD cases per district. Logistic and Poisson regression analyses were used to compute risk and rate estimates. Nationwide, the number of in-hospital deliveries and C-sections decreased by over 20% during the EVD outbreak. The decline occurred early on in the EVD outbreak and was mainly attributable to the closing of private not-for-profit hospitals rather than government facilities. Due to difficulties in collecting data in the midst of an epidemic, limitations of this study include some missing data points.Conclusions
Both the number of in-hospital deliveries and C-sections substantially declined shortly after the onset of the EVD outbreak. Since access to emergency obstetric care, like C-sections, is associated with decreased maternal mortality, many women are likely to have died due to the reduced access to appropriate care during childbirth. Future research on indirect health effects of health system breakdown should ideally be nationwide and continue also into the recovery phase. It is also important to understand the mechanisms behind the deterioration so that important health services can be reestablished. 相似文献4.
A lumped model for cell growth and secondary metabolite production in an immobilized live cell bioreactor has been developed. This model is applied here to simulate the performance of an immobilized bioreactor under steady-state conditions and under conditions of periodically varying concentration of a growth-limiting substrate. The results of the simulation study were experimentally verified in the case of the production of the antibiotic candicidin by Streptomyces griseus in an immobilized bioreactor with forced periodic operation. The results of the studies suggest that periodically operated immobilized live cell bioreactors can provide a potent alternative for the production of non-growth-associated biochemicals, as compared to free cell fermentations, pulsed fermentations with process cycle regeneration, and nonregenerated bioreactors. This work has demonstrated that by frequent pulsing of the growth limiting nutrient, stable extended production can be obtained at high specific cellular productivities. 相似文献
5.
The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press. 相似文献
6.
Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections 总被引:11,自引:4,他引:11 下载免费PDF全文
A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules. 相似文献
7.
Alkis Constantinides Daleep Bhatia Wolf R. Vieth 《Biotechnology and bioengineering》1981,23(4):899-916
In this study, live cells of Brevibacterium flavum were immobilized for the production of glutamic acid. The reason for such a choice was that glutamic acid fermentation is an extensively studied fermentation and one which requires the viability of entire cellular faculties for the acid production. Brevibacterium flavum was chosen because it is an industrially used bacterium, and is very potent via a vis glutamic acid production. Studies were performed to find aeration and agitation conditions for optimal growth and glutamic acid productivity. Experiments were also done to find the optimum harvesting time. The cell activity peaks during the run of fermentation, and the time at which the peak occurs, was found. Conventional methods for immobilizing the cells on collagen were found to be lacking. The pH and drying were the two main reasons for loss of viability of the cells; the latter being more important. A modified immobilization procedure has been devised, which can immobilize live cells at any given pH and ionic strength, in contrast to the conventional method which requires the pH to be above 11 or below 3. This new method involves dialysis of collagen in suitable dialysis bags against water at pH7 (or buffer at any desired pH). The dialysed collagen blended at 20,000 rpm, resulted in a very smooth dispersion, unnoticeably different from collagen dispersion prepared at pH 11. The dispersed collagen was then cast and dried at an elevated temperature, and high air flow rate over the cast membrane, decreasing the time of drying from 6–8 hr ( in the conventional method) to 1.5–2 hr. The membrane has been tested for glutamic acid producing capabilities in a column reactor with the membrane spirally wound. The reactor has been operated under continuous conditions for 5–10 days with stable activities. 相似文献
8.
Substitution rates of organelle and nuclear genes in sharks: implicating metabolic rate (again) 总被引:3,自引:4,他引:3
Rates of nucleotide substitution for nuclear genes are thought to be
governed primarily by the number of germ line replication events (the
so-called "generation time" hypothesis). In contrast, rates of
mitochondrial DNA evolution appear to be set primarily by DNA damage
pathways of mutation mediated by mutagenic by-products of oxidative
phosphorylation (the so-called "metabolic-rate" hypothesis). Comparison of
synonymous substitution rates estimated for the mitochondrial cytochrome b
gene and nuclear-encoded dlx, hsp70, and RAG-1 genes in mammals and sharks
shows that rates of molecular evolution for sharks are approximately an
order of magnitude slower than those for mammals for both nuclear and
mitochondrial genes. In addition, there is significant positive covariation
of substitution rate for mitochondrial and nuclear genes within sharks.
These results, interpreted in light of the pervasiveness of DNA damage by
mutagenic by-products of oxygen metabolism to both nuclear and
mitochondrial genes and coupled with increasing evidence for cross-genome
activity of DNA repair enzymes, suggest that molecular clocks for
mitochondrial and nuclear genes may be set primarily by common mutational
mechanisms.
相似文献
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AP Shoko SM Limbu HA Lamtane MA Kishe-Machumu B Sekadende EE Ulotu 《African Journal of Aquatic Science》2019,44(1):15-24
Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system. 相似文献