Home About us Contact
|
Home About us Contact | ||
|
|
||
Thus
Kinds of Thus Selected AbstractsDifferential age-related changes in motor unit properties between elbow flexors and extensorsACTA PHYSIOLOGICA, Issue 1 2010B. H. Dalton Abstract Aim:, Healthy adult ageing of the human neuromuscular system is comprised of changes that include atrophy, weakness and slowed movements with reduced spinal motor neurone output expressed by lower motor unit discharge rates (MUDRs). The latter observation has been obtained mostly from hand and lower limb muscles. The purpose was to determine the extent to which elbow flexor and extensor contractile properties, and MUDRs in six old (83 ± 4 years) and six young (24 ± 1 years) men were affected by age, and whether any adaptations were similar for both muscle groups. Methods:, Maximal isometric voluntary contraction (MVC), voluntary activation, twitch contractile properties, force,frequency relationship and MUDRs from sub-maximal to maximal intensities were assessed in the elbow flexors and extensors. Results:, Both flexor and extensor MVCs were significantly (P < 0.05) less (,42% and ,46% respectively) in the old than in the young. Contractile speeds and the force,frequency relationship did not show any age-related differences (P > 0.05). For the elbow flexors contraction duration was ,139 ms and for the extensors it was ,127 ms for both age groups (P > 0.05). The mean MUDRs from 25% MVC to maximum were lower (,10% to ,36%) in the old than in the young (P < 0.01). These age-related differences were larger for biceps (Cohen's d = 8.25) than triceps (Cohen's d = 4.79) brachii. Conclusion:, Thus, at least for proximal upper limb muscles, mean maximal MUDR reductions with healthy adult ageing are muscle specific and not strongly related to contractile speed. [source] Effects of Habitat Disturbance on Stream Salamanders: Implications for Buffer Zones and Watershed ManagementCONSERVATION BIOLOGY, Issue 3 2003John D. Willson To minimize the impacts of development on aquatic habitats, numerous conservation measures have been implemented, including the use of riparian buffer zones along streams and rivers. We examined the effectiveness of current buffer-zone systems for management of small watersheds in conserving stream-dwelling salamander populations in 10 small streams ( draining <40.5 ha ) in the western Piedmont of North Carolina. We captured salamanders by means of funnel traps and systematic dipnetting and used a geographic information system to calculate the percentage of disturbed habitat within the watershed of each stream and within 10.7-, 30.5-, and 61.0 -m buffer zones around each stream, upstream from our sampling locations. Although the relative abundance of salamanders was strongly inversely proportional to the percentage of disturbed habitat in the entire watersheds ( R2 = 0.71 for Desmognathus fuscus and 0.48 for Eurycea cirrigera ), we found little to no correlation between the relative abundance of salamanders and the percentage of disturbed habitat present within buffer zones ( R2 = 0.06,0.27 for D. fuscus and 0.01,0.07 for E. cirrigera ). Thus, conservation efforts aimed at preserving salamander populations in headwater streams must consider land use throughout entire watersheds, rather than just preserving small riparian buffer zones. Resumen: La destrucción y degradación del hábitat se encuentra entre la mayores amenazas a la vida silvestre, junto con el aumento global de la población humana. Para minimizar los impactos del desarrollo sobre hábitats acuáticos, se han instrumentado numerosas medidas de conservación, incluyendo el uso de zonas de amortiguamiento riparias a lo largo de arroyos y ríos. Examinamos la efectividad de los actuales sistemas de zonas de amortiguamiento usados en el manejo de cuencas pequeñas para la conservación de poblaciones de salamandras de arroyo en 10 arroyos pequeños ( que drenan <40.5 ha ) al pie de monte del occidente de Carolina del Norte. Capturamos salamandras con trampas de embudo y mediante el uso sistemático de redes y utilizamos un sistema de información geográfica para calcular el porcentaje de hábitat perturbado dentro de la cuenca de cada arroyo y dentro de zonas de amortiguamiento de 10.7-, 30.5- y 61.0-m alrededor de cada arroyo, río arriba de nuestros sitios de muestreo. Aunque los valores de abundancia relativa de salamandras fueron inversamente proporcionales al porcentaje de hábitat perturbado en el total de las cuencas ( R2 = 0.71 para Desmognathus fuscus y 0.48 para Eurycea cirrigera ), encontramos una correlación débil o inexistente entre las abundancias relativas de salamandras y el porcentaje de hábitat perturbado en las zonas de amortiguamiento R2 = 0.06,0.27 para D. fuscus y 0.01,0.07 para E. cirrigera ). Por lo tanto, los esfuerzos de conservación dirigidos a preservar poblaciones de salamandras de arroyos de cabecera deben tomar en cuenta el uso de la tierra en la superficie entera de las cuencas, en lugar de preservar pequeñas zonas de amortiguamiento riparias. [source] Genetic aspects of the Paget's disease of bone: concerns on the introduction of DNA-based tests in the clinical practice.EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2010Advantages, disadvantages of its application Eur J Clin Invest 2010; 40 (7): 655,667 Abstract Background, A large amount of genetic studies have clearly demonstrated the existence of a genetic susceptibility to Paget's disease of bone (PDB). Although the disease is genetically heterogeneous, the SQSTM1/p62 gene, encoding a protein with a pathophysiological role in both osteoclast differentiation and activity, has been found worldwide to harbour germline mutations in most of the PDB patients from geographically distant populations originating from different areas of Europe, both in sporadic and familial cases. Materials and Methods, Thus, SQSTM1/p62 gene mutations may confer an increased lifetime risk of developing PDB. Results, Several different genotype-phenotype analyses have shown a high penetrance for such mutations. These results suggest the opportunity to perform genetic testing in affected individuals and then, after the identification of a SQSTM1/p62 gene germline mutation, in their relatives as a real and concrete strategy to increase the diagnostic sensitivity in most of the asymptomatic mutant carriers. However, it is of note to underlie that an incomplete penetrance for SQSTM1/p62 gene mutations has also been reported. Conclusions, In light of all these contradictory evidences, a review on whether, when and why apply the DNA test to those subjects, its interpretation and clinical application is necessary. In fact, a growing number of preventive care options are now available to affected patients and families and the process of systematically assessing risk is becoming increasingly important for both patients and physicians. [source] Kinetics of stem cell engraftment and clearance of leukaemia cells after allogeneic stem cell transplantation with reduced intensity conditioning in chronic myeloid leukaemiaEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2002Karl-Anton Kreuzer Abstract: It is hypothesised that an effective graft-vs.-leukaemia reaction contributes substantially to the therapeutic effect of reduced intensity conditioning stem cell transplantation in chronic myeloid leukaemia. However, kinetic data on eradication of leukaemia cells and stem cell engraftement which could support this assumption are lacking . Thus, we investigated bcr/abl fusion transcripts and haematopoietic chimerism in 14 patients undergoing such a transplantation protocol. Ten of them obtained a complete molecular remission, and two patients achieved haematologic remissions but remained bcr/abl positive. Weekly determinations of bcr/abl transcript numbers by qualitative and quantitative polymerase chain reaction and donor chimerism revealed that 10 responders cleared bcr/abl positive cells from the peripheral blood within a median of 9 wk (range 3,22 wk). The close relation (P = 0.0075) between the firstoccurrence of graft-vs.-host disease and the complete clearance ofbcr/abl positive blood cells argues in favour of an effective graft-vs.-leukaemia reaction. [source] EFFECTS OF GENETIC DRIFT ON VARIANCE COMPONENTS UNDER A GENERAL MODEL OF EPISTASISEVOLUTION, Issue 10 2004N.H. Barton Abstract We analyze the changes in the mean and variance components of a quantitative trait caused by changes in allele frequencies, concentrating on the effects of genetic drift. We use a general representation of epistasis and dominance that allows an arbitrary relation between genotype and phenotype for any number of diallelic loci. We assume initial and final Hardy-Weinberg and linkage equilibrium in our analyses of drift-induced changes. Random drift generates transient linkage disequilibria that cause correlations between allele frequency fluctuations at different loci. However, we show that these have negligible effects, at least for interactions among small numbers of loci. Our analyses are based on diffusion approximations that summarize the effects of drift in terms of F, the inbreeding coefficient, interpreted as the expected proportional decrease in heterozygosity at each locus. For haploids, the variance of the trait mean after a population bottleneck is var(,z,) =where n is the number of loci contributing to the trait variance, VA(1)=VA is the additive genetic variance, and VA(k) is the kth-order additive epistatic variance. The expected additive genetic variance after the bottleneck, denoted (V*A), is closely related to var(,z,); (V*A) (1 ,F)Thus, epistasis inflates the expected additive variance above VA(1 ,F), the expectation under additivity. For haploids (and diploids without dominance), the expected value of every variance component is inflated by the existence of higher order interactions (e.g., third-order epistasis inflates (V*AA)). This is not true in general with diploidy, because dominance alone can reduce (V*A) below VA(1 ,F) (e.g., when dominant alleles are rare). Without dominance, diploidy produces simple expressions: var(,z,)==1 (2F) kVA(k) and (V*A) = (1 ,F)k(2F)k-1VA(k) With dominance (and even without epistasis), var(,z,)and (V*A) no longer depend solely on the variance components in the base population. For small F, the expected additive variance simplifies to (V*A)(1 ,F) VA+ 4FVAA+2FVD+2FCAD, where CAD is a sum of two terms describing covariances between additive effects and dominance and additive × dominance interactions. Whether population bottlenecks lead to expected increases in additive variance depends primarily on the ratio of nonadditive to additive genetic variance in the base population, but dominance precludes simple predictions based solely on variance components. We illustrate these results using a model in which genotypic values are drawn at random, allowing extreme and erratic epistatic interactions. Although our analyses clarify the conditions under which drift is expected to increase VA, we question the evolutionary importance of such increases. [source] Quantitative analysis of the synthesis and secretion of type VII collagen in cultured human dermal fibroblasts with a sensitive sandwich enzyme-linked immunoassayEXPERIMENTAL DERMATOLOGY, Issue 2 2007Satoshi Amano Abstract:, Type VII collagen is the major component of anchoring fibrils in the epidermal basement membrane. Its expression has been analyzed by immunostaining or Northern blotting, but rarely at the protein level. In this study, we have quantitatively examined the effects of ascorbic acid and various cytokines/growth factors on the protein synthesis and secretion of type VII collagen by human dermal fibroblasts in culture, using a developed, highly sensitive sandwich enzyme-linked immunoassay with two kinds of specific monoclonal antibodies against the non-collagenous domain-1. Ascorbic acid and its derivative induced a twofold increase in type VII collagen synthesis, and markedly increased the secretion of type VII collagen into the medium when compared with the control culture. This effect was not influenced by the presence of transforming growth factor- ,1 (TGF- ,1). The synthesis of type VII collagen was elevated by TGF- ,1, platelet-derived growth factor, tumor necrosis factor- ,, and interleukin-1,, but not by TGF- ,. Thus, our data indicate that the synthesis and secretion of type VII collagen in human dermal fibroblasts are regulated by ascorbate and the enhancement of type VII collagen gene expression by cytokines/growth factors is accompanied with elevated production of type VII collagen at the protein level. [source] Carbon sequestration under Miscanthus: a study of 13C distribution in soil aggregatesGCB BIOENERGY, Issue 5 2009MARTA DONDINI Abstract The growing of bioenergy crops has been widely suggested as a key strategy in mitigating anthropogenic CO2 emissions. However, the full mitigation potential of these crops cannot be assessed without taking into account their effect on soil carbon (C) dynamics. Therefore, we analyzed the C dynamics through four soil depths under a 14-year-old Miscanthus plantation, established on former arable land. An adjacent arable field was used as a reference site. Combining soil organic matter (SOM) fractionation with 13C natural abundance analyses, we were able to trace the fate of Miscanthus -derived C in various physically protected soil fractions. Integrated through the whole soil profile, the total amount of soil organic carbon (SOC) was higher under Miscanthus than under arable crop, this difference was largely due to the input of new C. The C stock of the macroaggregates (M) under Miscanthus was significantly higher than those in the arable land. Additionally, the C content of the micro-within macroaggregates (mM) were higher in the Miscanthus soil as compared with the arable soil. Analysis of the intramicroaggregates particulate organic matter (POM) suggested that the increase C storage in mM under Miscanthus was caused by a decrease in disturbance of M. Thus, the difference in C content between the two land use systems is largely caused by soil C storage in physically protected SOM fractions. We conclude that when Miscanthus is planted on former arable land, the resulting increase in soil C storage contributes considerably to its CO2 mitigation potential. [source] Analyses of ultraviolet-induced focus formation of hREV1 proteinGENES TO CELLS, Issue 3 2006Yoshiki Murakumo Translesional DNA synthesis (TLS) is one of the DNA damage tolerance mechanisms that allow cells with DNA damage to continue DNA replication. Each of the mammalian Y-family DNA polymerases (Pol ,, Pol ,, Pol ,, and REV1) has been shown to carry out TLS by itself or in combination with another enzyme in vitro. Recently, the C-terminal region of mammalian REV1 (the total 1251 residues in human) was found to interact with Pol ,, Pol ,, and Pol ,, as well as with the REV7 subunit of another TLS enzyme, Pol ,. Thus, it is proposed that REV1 plays a pivotal role in TLS in vivo. We here describe our study on the localization of human REV1 protein (hREV1) in nondamaged and ultraviolet (UV)-irradiated cells. Ectopically expressed hREV1 in mammalian cells was localized to the nucleus and exhibited dozens of tiny foci in approximately 3% of nondamaged cells. The percentage of focus-forming cells markedly increased after UV irradiation in a time- and dose-dependent manner. The focus formation was associated with UV-induced DNA damage. Interestingly, although the hREV1 foci in S-phase cells colocalized with PCNA foci, suggesting the association of hREV1 with the replication machinery, hREV1 focus formation was observed not only in the S phase but also outside S phase. Furthermore, it was found that the hREV1 focus formation after UV irradiation required a region near the C-terminal (826,1178). [source] Usefulness of measuring serum markers in addition to comprehensive geriatric assessment for cognitive impairment and depressive mood in the elderlyGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2006Hidenori Arai Background: To determine the utility of various serum markers for assessment of cognitive and mental functions in the elderly, we performed a Comprehensive Geriatric Assessment (CGA) in the out-patient clinic in Kyoto University Hospital. Methods: We measured serum levels of dehydroepiandrosterone (DHEA), DHEA-S, malondialdehyde low-density lipoproteins (MDA-LDL), and high-sensitivity C-reactive protein (hs-CRP) in 145 patients to find the association of these markers with activities of daily living (ADL), cognitive impairment and depressive symptoms. Results: We found that the levels of hs-CRP were significantly higher in patients with lower scores in Mini-Mental State Examination (MMSE) and Kohs block design test, and higher scores in the button test, indicating that hs-CRP may be associated with the cognitive function in elderly patients. We also found that the levels of DHEA-S were lower in patients with higher scores (9 or over) on the Geriatric Depression Scale-15 (GDS), indicating that DHEA-S may be associated with depressive mode in elderly patients. Total cholesterol, high-density cholesterol (HDL-C), or albumin were not statistically different in each group studied. Conclusions: Thus, our data indicate that measuring hs-CRP and DHEA-S would be helpful to assess the cognitive function and depressive symptoms in elderly patients. [source] Temporal dynamics and spatial variability in the enhancement of canopy leaf area under elevated atmospheric CO2GLOBAL CHANGE BIOLOGY, Issue 12 2007HEATHER R. McCARTHY Abstract Increased canopy leaf area (L) may lead to higher forest productivity and alter processes such as species dynamics and ecosystem mass and energy fluxes. Few CO2 enrichment studies have been conducted in closed canopy forests and none have shown a sustained enhancement of L. We reconstructed 8 years (1996,2003) of L at Duke's Free Air CO2 Enrichment experiment to determine the effects of elevated atmospheric CO2 concentration ([CO2]) on L before and after canopy closure in a pine forest with a hardwood component, focusing on interactions with temporal variation in water availability and spatial variation in nitrogen (N) supply. The dynamics of L were reconstructed using data on leaf litterfall mass and specific leaf area for hardwoods, and needle litterfall mass and specific leaf area combined with needle elongation rates, and fascicle and shoot counts for pines. The dynamics of pine L production and senescence were unaffected by elevated [CO2], although L senescence for hardwoods was slowed. Elevated [CO2] enhanced pine L and the total canopy L (combined pine and hardwood species; P<0.050); on average, enhancement following canopy closure was ,16% and 14% respectively. However, variation in pine L and its response to elevated [CO2] was not random. Each year pine L under ambient and elevated [CO2] was spatially correlated to the variability in site nitrogen availability (e.g. r2=0.94 and 0.87 in 2001, when L was highest before declining due to droughts and storms), with the [CO2]-induced enhancement increasing with N (P=0.061). Incorporating data on N beyond the range of native fertility, achieved through N fertilization, indicated that pine L had reached the site maximum under elevated [CO2] where native N was highest. Thus closed canopy pine forests may be able to increase leaf area under elevated [CO2] in moderate fertility sites, but are unable to respond to [CO2] in both infertile sites (insufficient resources) and sites having high levels of fertility (maximum utilization of resources). The total canopy L, representing the combined L of pine and hardwood species, was constant across the N gradient under both ambient and elevated [CO2], generating a constant enhancement of canopy L. Thus, in mixed species stands, L of canopy hardwoods which developed on lower fertility sites (,3 g N inputs m,2 yr,1) may be sufficiently enhanced under elevated [CO2] to compensate for the lack of response in pine L, and generate an appreciable response of total canopy L (,14%). [source] Immobilization, stabilization and remobilization of nitrogen in forest soils at elevated CO2: a 15N and 13C tracer studyGLOBAL CHANGE BIOLOGY, Issue 10 2005Frank Hagedorn Abstract The fate of immobilized N in soils is one of the great uncertainties in predicting C sequestration at increased CO2 and N deposition. In a dual isotope tracer experiment (13C, 15N) within a 4-year CO2 enrichment (+200 ppmv) study with forest model ecosystems, we (i) quantified the effects of elevated CO2 on the partitioning of N; (ii) traced immobilized N into physically separated pools of soil organic matter (SOM) with turnover rates known from their 13C signals; and (iii) estimated the remobilization and thus, the bio-availability of newly sequestered C and N. (1) CO2 enrichment significantly decreased NO3, concentrations in soil waters and export from 1.5 m deep lysimeters by 30,80%. Consequently, elevated CO2 increased the overall retention of N in the model ecosystems. (2) About 60,80% of added 15NH415NO3 were retained in soils. The clay fraction was the greatest sink for the immobilized 15N sequestering 50,60% of the total new soil N. SOM associated with clay contained only 25% of the total new soil C pool and had small C/N ratios (<13), indicating that it consists of humified organic matter with a relatively slow turn over rate. This implies that added 15N was mainly immobilized in stable mineral-bound SOM pools. (3) Incubation of soils for 1 year showed that the remobilization of newly sequestered N was three to nine times smaller than that of newly sequestered C. Thus, inorganic inputs of N were stabilized more effectively in soils than C. Significantly less newly sequestered N was remobilized from soils previously exposed to elevated CO2. In summary, our results show firstly that a large fraction of inorganic N inputs becomes effectively immobilized in relative stable SOM pools and secondly that elevated CO2 can increase N retention in soils and hence it may tighten N cycling and diminish the risk of nitrate leaching to groundwater. [source] Ergonomics interventions for wafer-handling task in semiconductor manufacturing industryHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 3 2002Hsiu-Chen Chung This article presents the ergonomic interventions in a semiconductor manufacturing company, with a focus on evaluating the effect of pod (wafer container) type and carrying distance on participants' maximal acceptable weight of lift (MAWL), heart rate (HR), wrist posture, and perceived exertion rating. Sixteen field operators participated in this study. The results indicate using the new pod with power grip handles produced greater MAWL than the old pod with pinch grip handles. On the other hand, the new pod also induced greater radial deviations than the old type. Recommendation for improving pod handle design is provided. Further, the increased carrying distance caused a decrease in MAWL and an increase in HR. Thus, using cart for intrabay pod transfer and minimizing manual carrying is also recommended. © 2002 Wiley Periodicals, Inc. [source] Barriers for dental treatment of primary teeth in East and West GermanyINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 2 2009CHRISTIAN H. SPLIETH Background., In many countries, restorative treatment in primary teeth is suboptimal. Aim., Thus, this study tried to detect barriers for dentists to restore primary teeth in kindergarten children (3,6 years). Design., For a representative survey, 320 dentists (184 West, 136 East Germany) were randomly selected from the dental associations' registers and asked to answer a questionnaire on their profile, their view of the National Health System, and possible barriers for restoring primary teeth. Results., The analysis (response rate 57.7%) showed that the parents were no barrier and the dentists felt the need of restoring primary teeth. In addition to the children's anxiety, the inadequate reimbursement for fillings were perceived as clear barrier. The comparison of West and East German dentists detected statistically significantly higher barriers in West Germany, where , in contrast to the German Democratic Republic , no structured training in paediatric dentistry was compulsory before unification. Only 35% of the East German dentists rated restorative treatment in 3- to 6-year-olds as stressful in contrast to 65% in West Germany, where especially male dentists found no time to treat children. Conclusion., This study reveals that dentists can also be a considerable barrier to restorative treatment in small children, especially without adequate training in dental schools. [source] Relating juvenile spatial distribution to breeding patterns in anadromous salmonid populationsJOURNAL OF ANIMAL ECOLOGY, Issue 2 2010Anders Foldvik Summary 1. Spatial within-population heterogeneity in density probably affects competition intensity and may have a fundamental role in shaping population dynamics and carrying capacity. This may be particularly relevant for organisms where limitations on juvenile mobility cause maternal choice of breeding locations to influence the spatial distribution of younger life stages. 2. In this study, we mapped redd locations and the resulting densities of juveniles the following year along the entire reach (9·2 km) of a river holding natural populations of anadromous salmonids (Atlantic salmon and brown trout). These data were used to quantify the spatial scale over which breeding influences juvenile densities, and hence becomes important for density-dependent processes. 3. Although the observed cumulative distributions indicated a relatively uniform distribution of breeding along the river, autocorrelation analyses identified spatial patchiness of both breeding and resulting juveniles on a local scale. Furthermore, cross-correlations suggested a close spatial relationship between distribution of redds and juveniles. 4. Using spatially explicit hockey-stick stock,recruitment functions, we found juvenile salmonid density to be mostly influenced by the amount of breeding upstream of a given location. This influence decreased rapidly within the first 75,150 m. Thus, female choice with regard to breeding location gave rise to a heterogeneous distribution of offspring on a spatial scale of almost two orders of magnitude finer than that of the whole population (9·2 km). 5. The results are consistent with smaller scale experimental studies of salmonids, and emphasize the role for maternal choice of breeding locations in causing substantial spatial heterogeneity in juvenile densities within natural populations. Due to effects of density heterogeneity on overall levels of competition, this adds another layer of complexity to the dynamics of salmonid populations even in populations where breeding appears to be relatively uniformly distributed through space, and potentially also for a range of other organisms where juvenile dispersal is constrained. [source] Prevalence of vaccine-derived polioviruses in stools of immunodeficient children in South AfricaJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006D.N. Pavlov Abstract Aims:, The aim of the study was to determine the prevalence of vaccine-derived polioviruses (VDPVs) in stool specimens of immunodeficient patients such as HIV-positive children (including those with an AIDS indicator condition, according to the Centres for Disease Control and Prevention classification) by applying various molecular techniques. Methods and Results:, A total of 164 stool samples from HIV-positive children and 23 stool samples from healthy immunocompetent children (the control group) were analysed during 2003 and 2004. By applying a reverse transcription polymerase chain reaction (RT-PCR) in combination with a nested PCR, a total of 54 enteroviruses were detected in the stool specimens of the immunodeficient children. The use of restriction enzymes and a Sabin specific RT-triplex PCR confirmed the presence of 13 polioviruses (PVs), such as seven Sabin PV type 1, four Sabin PV type 3 and two Sabin PV type 2 isolates. The 5,untranslated region and the VP1 capsid-encoding protein of the 13 PVs and the three PVs from the stools of the immunocompetent children were partially sequenced and their genetic relatedness was deduced from the constructed phylogenetic trees. The majority of the PVs isolated from the stools of the immunodeficient children (10 of 13 isolates) were classified as ,oral poliovirus vaccine (OPV)-like viruses', as these isolates had close sequence relationships (>99% in VP1 nucleotide sequences) to the original Sabin PV vaccine strains. Three PVs showed ,99% VP1 sequence identity to the Sabin PV vaccine strains and were classified as ,suspected' immunodeficient VDPVs (iVDPVs). All of the OPV-like isolates and the ,suspected' iVDPVs carried mutations at specific positions in their partially sequenced regions, which have been associated with reversion of the attenuated Sabin PV vaccine strains to increased neurovirulence. Conclusions:, Thus, this study adds further evidence to the observation that immunodeficient individuals may excrete OPV strains with potential neurovirulent phenotypes. Significance and Impact of the Study:, Prolonged excretion of PVs by immunodeficient individuals is of major concern, because continued replication of PVs in the human gut could result in the reversion of these viruses to greater neurovirulence. When exposed to OPV, immunodeficient patients may become chronically infected, spreading potentially neurovirulent VDPVs for many months or years to close contacts and children who are no longer being vaccinated after termination of OPV vaccination in the near future. [source] Disposition and pharmacokinetics of a lubricant contaminant, 2,6-di- tert -butyl 4-nitrophenol, in grafted human skinJOURNAL OF APPLIED TOXICOLOGY, Issue 5 2006Lynn K. Pershing Abstract Disposition and uptake/elimination profiles of topical 2,6-di- t -butyl, 4-nitrophenol (DBNP), the nitrated metabolite of an antioxidant additive of lubricant and hydraulic fluids was quantified in human skin grafted on athymic mice after a single topical 75 µg dose in corn oil. DBNP was quantified throughout the stratum corneum (SC), epidermis (E) and dermis (D) in punch biopsies collected from treated skin 0.5, 1, 2, 4, 8 and 24 h after application. SC samples were harvested from the treated skin with 20 adhesive discs. E and D were generated from the biopsy using a manual sectioning method. Detectable DBNP concentrations were measured in all skin compartments at all time points investigated. The Cmax of DBNP in SC was 1663 ± 602 µg cm,3, and ,30 and ,300 fold greater than the Cmax for E and D, respectively. Tmax occurred at 1.0, 0.5 and 1.0 in the SC, E and D, respectively. Over a 24 h interval (AUC0,24 h) there was 52 and 520 fold more DBNP in the SC than E and D, respectively. The elimination half-life of DBNP was 11 h from the SC and 9 h from both E and D. Thus, DBNP was quickly absorbed into the outermost layer of skin and established a steep concentration profile through human skin. The data are consistent with the vast majority of DBNP remaining on the surface (77%) or within human skin (15%) in vivo with only 0.2% of the DBNP dose quantified in the systemic blood circulation. Copyright © 2006 John Wiley & Sons, Ltd. [source] Rheological properties of acrylic bone cement during curing and the role of the size of the powder particlesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Gladius Lewis Abstract A dynamic compressive rheometric technique was used to determine the true or complex viscosity (,*) of three poly (methyl methacrylate), PMMA-based bone cement formulations (one commercially available and two experimental), as a function of the time that elapsed from commencement of hand mixing of the cement constituents (t). For each cement, two rheological parameters [namely, the time of onset of cure (tons) and the critical cure rate (CCR), which is herein defined as the complex viscosity rate computed at tons] were determined from the ,*,t data. For each cement, particle analysis was used to obtain the powder particle size distribution, from which the following parameters were obtained: (a) the overall mean particle diameter Dm, and (b) the relative amounts of small-sized PMMA beads (mean diameter d between 0 and 40 ,m) (,) and large-sized PMMA beads (d > 75 ,m) (,). It is seen that the key particle parameter is not Dmper se but , and ,. Thus, the highest values of tons and CCR were obtained from a cement with the highest values of , and ,. An explanation for these trends is given, and two areas for further research work in this field are outlined. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 63: 191,199, 2002; DOI 10.1002/jbm.10127 [source] Epidermal growth factor stimulates proton efflux from chondrocytic cellsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2002Kevin E.H. Lui Proton efflux from chondrocytes alters the extracellular pH and ionic composition of cartilage, and influences the synthesis and degradation of extracellular matrix. Epidermal growth factor (EGF) promotes chondrocyte proliferation during skeletal development and accumulates in the synovial fluid in rheumatoid arthritis. The purpose of this study was to investigate the effect of EGF on proton efflux from chondrocytes. When monitored using a Cytosensor microphysiometer, EGF was found to rapidly activate proton efflux from CFK2 chondrocytic cells and rat articular chondrocytes. The actions of EGF were concentration-dependent with half-maximal effects at 0.3,0.7 ng/ml. Partial desensitization and time-dependent recovery of the response were observed following repeated exposures to EGF. EGF-induced proton efflux was dependent on extracellular glucose, and inhibitors of Na+/H+ exchange (NHE) markedly attenuated the initial increase in proton efflux. The response was diminished by inhibitors of phosphatidylinositol 3-kinase and phospholipase C, but not by inhibitors of MEK (MAPK/ERK kinase) or protein kinase A or C. Thus, EGF-induced proton efflux involves glucose metabolism and NHE, and is regulated by a discrete subset of EGF-activated signaling pathways. In vivo, proton efflux induced by EGF may lead to an acidic environment, enhancing turnover of cartilage matrix during development and in rheumatoid arthritis. © 2002 Wiley-Liss, Inc. [source] Inoculum strategies for Penicillium simplicissimum lipase production by solid-state fermentation using a residue from the babassu oil industryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2007Melissa L. E. Gutarra Abstract Two alternative inoculation strategies for lipase production by the fungus Penicillium simplicissimum were tested in solid-state fermentation using a residue from the babassu oil industry (babassu cake). Conventional spore inoculation was compared with fungal pellets grown in liquid medium and with inocula consisting of fermented cake. Fungal pellets delayed lipase production whereas fermented cake accelerated enzyme synthesis, yielding a productivity of 0.45 U g,1 h,1, which is equivalent to the highest values obtained with conventional inocula. Therefore, a 22 factorial design was used to determine the best conditions for lipase production with fermented cake as inoculum strategy, varying the inoculum propagation time and inoculum concentration. Lipase activity and productivity reached 30 U g,1 and 0.63 U g,1 h,1, respectively, with 10% inoculum and 36 h. Thus, fermented cake inocula increased production 1.5-fold with 10 times fewer spores than in conventional inoculation, indicating that fermented solids are an interesting alternative for inoculum development in solid-state fermentation, mainly for large-scale processes. Copyright © 2007 Society of Chemical Industry [source] A Continuous High Pressure Carbon Dioxide System for Microbial Reduction in Orange JuiceJOURNAL OF FOOD SCIENCE, Issue 5 2005Dilek Kincal ABSTRACT: A continuous high-pressure carbon dioxide system, run at ambient conditions, was tested on its performance in reducing both natural and inoculated microbial loads. The prototype system continuously processes orange juice with carbon dioxide (CO2) at high pressures. A central composite design was originally used to examine the variables of pressure, residence time, and CO2/juice ratio. For microbial reduction, residence time was the major factor followed by pressure. The CO2/juice ratio showed no influence on microbial load, and in this equipment, was difficult to control. The unit was able to cause a 5-log reduction of the natural flora in spoiled juice, and could attain a 5-log decrease in numbers of pathogenic Escherichia coli O157:H7, Salmonella typhimurium, and Listeriamonocytogenes. No viable cells of E. coli O157:H7 orS. typhimurium were cultured after the treated juices were stored at room temperature (22 °C) for 14 d. Thus, non-thermal pathogen reduction is possible with this system. [source] Dysplasia and carcinoma development in a repeated dextran sulfate sodium-induced colitis modelJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2002Isao Okayasu Abstract Background: As an important mechanism underlying the increased risk of colorectal carcinoma development in patients with long-standing ulcerative colitis, promotion as a result of the regenerative process has been proposed. In the present study, a dysplasia-carcinoma sequence in a novel repeated colitis model in mice is documented. Methods: Repeated colitis was induced by nine administration cycles of 3% dextran sulfate sodium (DSS; molecular weight, 54 000): each administration cycle comprised 3% DSS for 7 days followed by distilled water for the subsequent 14 days, to give conditions similar to the clinically observed active and remission phases in humans. Results: Multiple colorectal tumors (nine low- and four high-grade dysplasias and two carcinomas) developed in 25 mice. These neoplastic lesions consisted of tubular structures, presenting as various types of elevated, flat and depressed tumor, similar to those in ulcerative colitis patients. A time-course study with assessment of the severity of colitis and in vivo bromodeoxyuridine uptake during a single 3% DSS administration cycle revealed a high level of regenerative activity in the colitis-affected mucosal epithelia. Conclusion: Thus, with the present repeated colitis model, regeneration and neoplastic lesions were apparent, the biological features of which provide evidence of a colorectal dysplasia,invasive carcinoma sequence in ulcerative colitis. [source] Difference in prognosis between patients infected with hepatitis B virus with genotype B and those with genotype C in the Okinawa Islands: A prospective studyJOURNAL OF MEDICAL VIROLOGY, Issue 3 2003Tomokuni Nakayoshi Abstract The factors contributing to the prognosis of hepatitis B virus (HBV)- related chronic liver disease were assessed prospectively in 72 patients with chronic hepatitis B confirmed clinically and pathologically. A comparative study was undertaken between patients infected with genotype B and those with genotype C. During the follow-up period, 13 (81.3%) of 16 patients with genotype B who were initially hepatitis B e antigen (HBeAg) positive became HBeAg negative and 14 (51.9%) of 27 with genotype C became HBeAg negative. HBeAg had been cleared in 8 (61.5%) of 13 patients with genotype B within the first 2 years of the follow-up, but in only one (7.1%) of 14 with genotype C (P,<,0.05). Four (11.4%) of 35 patients with genotype B had progressed to cirrhosis, whereas, 12 (32.4%) of 37 patients with genotype C progressed to cirrhosis, including two patients with hepatocellular carcinoma. Multivariate analysis showed that difference in HBV genotype influenced significantly either the clearance of HBeAg or the development of cirrhosis. In conclusion, HBeAg was cleared from sera more frequently and earlier in patients with genotype B compared with those with genotype C, and development of cirrhosis occurred less frequently in patients with genotype B compared with those with genotype C. Thus, HBV genotypes may influence the prognosis of HBV-related chronic liver disease. J. Med. Virol. 70:350,354, 2003. © 2003 Wiley-Liss, Inc. [source] Diazepam Promotes ATP Recovery and Prevents Cytochrome c Release in Hippocampal Slices After In Vitro IschemiaJOURNAL OF NEUROCHEMISTRY, Issue 3 2000Francesca Galeffi Abstract: Benzodiazepines protect hippocampal neurons when administered within the first few hours after transient cerebral ischemia. Here, we examined the ability of diazepam to prevent early signals of cell injury (before cell death) after in vitro ischemia. Ischemia in vitro or in vivo causes a rapid depletion of ATP and the generation of cell death signals, such as the release of cytochrome c from mitochondria. Hippocampal slices from adult rats were subjected to 7 min of oxygen-glucose deprivation (OGD) and assessed histologically 3 h after reoxygenation. At this time, area CA1 neurons appeared viable, although slight abnormalities in structure were evident. Immediately following OGD, ATP levels in hippocampus were decreased by 70%, and they recovered partially over the next 3 h of reoxygenation. When diazepam was included in the reoxygenation buffer, ATP levels recovered completely by 3 h after OGD. The effects of diazepam were blocked by picrotoxin, indicating that the protection was mediated by an influx of Cl - through the GABAA receptor. It is interesting that the benzodiazepine antagonist flumazenil did not prevent the action of diazepam, as has been shown in other studies using the hippocampus. Two hours after OGD, the partial recovery of ATP levels occurred simultaneously with an increase of cytochrome c (,400%) in the cytosol. When diazepam was included in the reoxygenation buffer, it completely prevented the increase in cytosolic cytochrome c. Thus, complete recovery of ATP and prevention of cytochrome c release from mitochondria can be achieved when diazepam is given after the loss of ATP induced by OGD. [source] Topology and patch-clamp analysis of the sodium channel in relationship to the anti-lipid a antibody in campylobacteriosisJOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2008Seigo Usuki Abstract An infecting strain VLA2/18 of Campylobacter jejuni was obtained from an individual with campylobacteriosis and used to prepare chicken sera by experimental infection to investigate the role of serum anti-ganglioside antibodies in Guillain-Barré syndrome. Both sera of the patient and chicken contained anti-ganglioside antibodies and anti-Lipid A (anti-Kdo2-Lipid A) antibodies directed against the lipid A portion of the bacterial lipooligosaccharide. The anti-Kdo2-Lipid A activities inhibited voltage-gated Na (Nav) channel of NSC-34 cells in culture. We hypothesized that anti-Kdo2-Lipid A antibody acts on the functional inhibition of Nav1.4. To test this possibility, a rabbit peptide antibody (anti-Nav1.4 pAb) against a 19-mer peptide (KELKDNHILNHVGLTDGPR) on the , subunit of Nav1.4 was produced. Anti-Nav1.4 pAb was cross-reactive to Kdo2-Lipid A. Anti-Kdo2-lipid A antibody activity in the chicken serum was tested for the Na+ current inhibition in NSC-34 cells in combination with ,-Conotoxin and tetrodotoxin. Contrary to our expectations, the anti-Kdo2-Lipid A antibody activity was extended to Nav channels other than Nav1.4. By overlapping structural analysis, it was found that there might be multiple peptide epitopes containing certain dipeptides showing a structural similarity with v-Lipid A. Thus, our study suggests the possibility that there are multiple epitopic peptides on the extracellular domains of Nav1.1 to 1.9, and some of them may represent target sites for anti-Kdo2-Lipid A antibody, to induce neurophysiological changes in GBS by disrupting the normal function of the Nav channels. © 2008 Wiley-Liss, Inc. [source] Isoflurane attenuates dynorphin-induced cytotoxicity and downregulation of Bcl-2 expression in differentiated neuroblastoma SH-SY5Y cellsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2009G.-J. WU Background: It has been proposed that the volatile anesthetic isoflurane induces neuroprotection and that the endogenous opioid peptide dynorphin induces neurocytotoxicity in cells. The levels of dynorphin are often significantly elevated in neuropathophysiological conditions, and dynorphin can directly induce toxicity. However, the neuroprotective effects of isoflurane on dynorphin-induced cytotoxicity are still unclear. Methods: In order to determine the effect of isoflurane on dynorphin-induced cytotoxicity in neuronal cells, we have designed a device wherein cultured human neuroblastoma SH-SY5Y cells can be exposed to isoflurane. Fully differentiated SH-SY5Y cells were obtained by treating the cells with retinoic acid for 6 days. We examined SH-SY5Y cell survival, apoptosis, and antiapoptotic protein expression by cell viability, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling stain, and Western blot analysis, respectively. Results: After 16 h of dynorphin (10 ,M) treatment, the SH-SY5Y cells showed significant cytotoxicity, apoptosis, and downregulation of the antiapoptotic Bcl-2 protein expression. These effects of dynorphin were significantly inhibited by isoflurane exposure for 32 h [pretreatment for 16 h and posttreatment (after dynorphin treatment) for 16 h]. Conclusion: Thus, our results suggest that isoflurane exerts neuroprotective effects in the case of dynorphin-induced pathophysiological disruption. [source] Processing-induced phase transitions of theophylline,implications on the dissolution of theophylline tabletsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2007Jaidev S. Tantry Abstract Aqueous wet massing of stable anhydrous theophylline (A) with polyvinylpyrrolidone (PVP) resulted in its complete transformation to theophylline monohydrate (M). Drying at 45°C, resulted in the formation of metastable anhydrous theophylline (A*) which then transformed to A. PVP, a known crystallization inhibitor, was effective in inhibiting the A*,,,A transition. The higher molecular weight polymer, PVP K90, was more effective in inhibiting the A*,,,A transition as compared to PVP K17. The disappearance of M, and the formation of A* and A was simultaneously monitored by XRD. An increase in the drying temperature from 45 to 55°C accelerated the A*,,,A transition. In granules prepared by the high-shear process, approximately 50% of theophylline existed as A and the rest as A*. In contrast, the fluid-bed granulation process yielded granules containing only A. Thus, the physical form of theophylline in tablets was influenced by the molecular weight of the binding agent, the granulation method, and the drying temperature. Using A as the starting material, tablets were manufactured by high-shear aqueous wet granulation process and the A* content was quantified. These tablets were stored under various relative humidity (RH) conditions at 25°C for 2 weeks. Storage at RH,,,33% caused complete A*,,,A conversion accompanied by a pronounced decrease in the initial dissolution rate indicating that phase transitions during processing and storage can have a significant influence on product performance. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 1434,1444, 2007 [source] In vitro synergistic effect of gentamicin with the anti-inflammatory agent diclofenac against Listeria monocytogenesLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009N.K. Dutta Abstract Aims:, A total of nine Listeria monocytogenes strains (seven serotypes) were studied to ascertain whether the non-steroidal anti-inflammatory drug diclofenac (Dc) used in combination with the conventional antilisterial antibiotic gentamicin (Gm) or ampicillin (Am) synergistically augments the efficacy of the antibiotic in vitro. Methods and Results:, The effect of combination was evaluated by the checkerboard method to obtain a fractional inhibitory concentration (FIC) index followed by kill curves. Dc was synergistic with Gm (FIC 0·37) and there was indifference with Am (FIC 1) against L. monocytogenes ATCC 51774. The magnitude of the differences between killing by a single agent and the combination observed at 24 h was significant (P < 0·05) for Dc plus Gm but not Dc plus Am. Conclusions:, Thus, the ability of extended antibiotic therapy may be improved with the help of this synergistic drug pair in listeriosis. Significance and Impact of the Study:, Such findings may indicate parallel administration of anti-inflammatory and anti listeriosis drugs. [source] Rapid detection of Haemophilus influenzae by hel gene polymerase chain reactionLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2003M.C. Yadav Abstract Aims: To evaluate the efficiency of hel gene polymerase chain reaction (PCR) to detect Haemophilus influenzae in various clinical/non-clinical samples. Methods and Results: Seventy-four clinical samples (cerebrospinal fluid, blood, sputum, throat and nasal swabs) and throat swabs of 17 asymptomatic carriers were collected. Primers were used to amplify the hel gene of H. influenzae encoding P4 outer membrane protein directly from the processed samples. The samples were also examined by conventional culture methods and the results were compared with those of PCR. The culture methods showed positive results in 60 (65·9%) of 91 samples in contrast to 62 (68·12%) samples tested positive by PCR. None of the culture-positive samples were PCR-negative while two of the culture-negative samples were PCR-positive. The specificity of the products was confirmed by Southern hybridization and failure of various other organisms to amplify the hel gene product. The sensitivity of the PCR assay was found to be 50 pg of DNA. Conclusions: These findings suggest that the hel gene PCR is a rapid, sensitive and a specific new method for direct identification of H. influenzae. Significance and Impact of the study: Thus, this PCR test can improve the detection rate of H. influenzae in suspected clinical samples as compared with that of conventional culture methods. [source] Local existence for the one-dimensional Vlasov,Poisson system with infinite massMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 5 2007Stephen Pankavich Abstract A collisionless plasma is modelled by the Vlasov,Poisson system in one dimension. We consider the situation in which mobile negative ions balance a fixed background of positive charge, which is independent of space and time, as ,x, , ,. Thus, the total positive charge and the total negative charge are both infinite. Smooth solutions with appropriate asymptotic behaviour are shown to exist locally in time, and criteria for the continuation of these solutions are established. Copyright © 2006 John Wiley & Sons, Ltd. [source] Variable small protein (Vsp)-dependent and Vsp-independent pathways for glycosaminoglycan recognition by relapsing fever spirochaetesMOLECULAR MICROBIOLOGY, Issue 4 2000Loranne Magoun Tick-borne relapsing fever, caused by pathogenic Borrelia such as B. hermsii and B. turicatae, features recurrent episodes of bacteraemia, each of which is caused by a population of spirochaetes that expresses a different variable major protein. Relapsing fever is also associated with the infection of a variety of tissues, such as the central nervous system. In this study, we show that glycosaminoglycans (GAGs) mediate the attachment of relapsing fever spirochaetes to mammalian cells. B. hermsii strain DAH bound to immobilized heparin, and heparin and dermatan sulphate blocked bacterial binding to host cells. Bacterial binding was diminished by inhibition of host cell GAG synthesis or sulphation, or by the enzymatic removal of GAGs. GAGs mediated the attachment of relapsing fever spirochaetes to potentially relevant target cells, such as endothelial and glial cells. B. hermsii was able to attach to GAGs independently of variable major proteins, because strains expressing the variable major proteins Vsp33, Vlp7 or no variable major protein at all each recognized GAGs. Nevertheless, we found that a variable major protein of B. turicatae directly promoted GAG binding by this relapsing fever spirochaete. B. turicatae strain Oz1 serotype B, which expresses the variable major protein VspB, bound to GAGs more efficiently than did B. turicatae Oz1 serotype A, which expresses VspA. Recombinant VspB, but not VspA, bound to heparin and dermatan sulphate. Previous studies have shown that strain Oz1 serotype B grows to higher concentrations in the blood than does Oz1 serotype A. Thus, relapsing fever spirochaetes have the potential to express Vsp-dependent and Vsp-independent GAG-binding activities and, for one pair of highly related B. turicatae strains, differences in GAG binding correlate with differences in tissue tropism. [source] | ||||||||||||||||||||||||||||||||||||||||