Medical Library

Activity of abrB310 promoter in wild type and spo0A-deficient strains of Clostridium acetobutylicum.

In Clostridium acetobutylicum, abrB310 is transcribed from two transcription start sites (designated A1 and A2) forming an abundant large, and a five- to tenfold less abundant small transcript, respectively throughout exponential, acidogenic growth and early in the transitional period to stationary, solventogenic growth. beta-galactosidase reporter vectors were constructed to compare the transcriptional activity of the entire abrB310 promoter and the A1 and A2 transcription start sites individually. In stark contrast to the primer extension data, the A2 start site was threefold more active than the entire promoter, which was threefold more active than the A1 start site in wild type C. acetobutylicum. The activity expressed from all three reporter vectors declined as the cultures transitioned from exponential to stationary growth. In the spo0A-deficient strain SKO1, reporter vector activity continued for 10 h into stationary growth. The removal of the putative Spo0A binding site from all three vectors had no significant effect on promoter activity in either wild type or SKO1. We conclude that the presence of both the A1 and A2 transcription start sites is required for the correct control of abrB310 expression, and that AbrB310 is necessary but not sufficient for the correct transition between acidogenic and solventogenic growth.

Scotcher MC, Bennett GN.

Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, Houston, TX, 77005, USA.

Determination of human arterial wall parameters from clinical data.

This study suggests a method to compute the material parameters for arteries in vivo from clinically registered pressure-radius signals. The artery is modelled as a hyperelastic, incompressible, thin-walled cylinder and the membrane stresses are computed using a strain energy. The material parameters are determined in a minimisation process by tuning the membrane stress to the stress obtained by enforcing global equilibrium. In addition to the mechanical model, the study also suggests a preconditioning of the pressure-radius signal. The preconditioning computes an average pressure-radius cycle from all consecutive cycles in the registration and removes, or reduces, undesirable disturbances. The effect is a robust parameter identification that gives a unique solution. The proposed method is tested on clinical data from three human abdominal aortas and the results show that the material parameters from the proposed method do not differ significantly (p < 0.01) from the corresponding parameters obtained by averaging the result from consecutive cycles.

Stålhand J.

Division of Mechanics, Linköping Institute of Technology, 581 83, Linköping, Sweden, jonas.stalhand@liu.se.

Redistributive effects in public health care financing.

This article focuses on the redistributive effects of different measures to finance public health insurance. We analyse the implications of different financing options for public health insurance on the redistribution of income from good to bad health risks and from high-income to low-income individuals. The financing options considered are either income-related (namely income taxes, payroll taxes, and indirect taxes), health-related (co-insurance, deductibles, and no-claim), or neither (flat fee). We show that governments who treat access to health care as a basic right for everyone should consider redistributive effects when reforming health care financing.

Honekamp I, Possenriede D.

Chair of Empirical Microeconomics, University of Bamberg, Feldkirchenstr. 21, 96045, Bamberg, Germany, ivonne.honekamp@uni-bamberg.de.

Serogroup distribution and antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae among Beijing children with upper respiratory infections (2000-2005).

The aims of this study were to estimate pneumococcal carriage rate, antimicrobial resistance and serogroup distribution of nasopharyngeal isolates of Streptococcus pneumoniae among children with acute upper respiratory infections (AURIs) aged 1 month to 5 years attending outpatient department of the Beijing Children\’s Hospital between 2000 and 2005. Susceptibilities to penicillin, amoxicillin-clavulanic acid, ceftriaxone, cefuroxime, cefaclor, erythromycin, tetracycline, sulfamethoxazole-trimethoprim and chloramphenicol were assessed using the E-test and disc diffusion. We also analyzed the correlation between antibiotic consumption and rates of resistance. The prevalence of penicillin-nonsusceptible pneumococci increased from 26% during 2000-2001 and 21% during 2002-2003 to 31.5% in 2004-2005. The percentage of S. pneumoniae resistant to cefaclor and cefuroxime increased from about 6% during 2000-2001 to about 23% during 2004-2005 (P<0.01). The frequency of resistance to erythromycin ranged from 87% to 94%. Tetracycline and co-trimoxazole resistance rates were greater than 80%. We conclude that resistance rates for most antibiotics are increasing, possibly due to misues of antibiotics in the hospital setting. However, chloramphenicol resistance was found to decrease, which correlated with the cessation of chloramphenicol administration in 1999. Pneumococcal strains (n=519) were analyzed by serogroup, and only 296 were found to be seven-valent pneumococcal conjugate vaccine-related serotype isolates. This serotype distribution is important for surveillance of the new conjugate vaccine.

Yu S, Yao K, Shen X, Zhang W, Liu X, Yang Y.

Department of Microbiology and Immunology, Beijing Children’s Hospital Affiliated to Capital Medical University, Nanlishi Road 56#, Beijing, 100045, China.

Epidemiologic impact of blood culture practices and antibiotic consumption on pneumococcal bacteraemia in children.

This study examined the roles of two different diagnostic approaches to children with fever of unknown origin in determining the patterns of pneumococcal bacteraemia in two Spanish regions by comparing their main epidemiologic characteristics. Whereas a blood culture is routinely obtained in this setting in Navarre, this is not generally the case in Majorca. Additionally, the potential role of antibiotic consumption in each region was also analysed. Cumulative incidences in children under the age of 14 years were 26.6 per 100,000 child-years in Navarre (121.1 in children <2 years of age) and 7.3 per 100,000 child-years in Majorca (33.3 in children <2 years of age). In contrast, the incidences per 1,000 blood cultures were similar in both regions. The relative risks of occult bacteraemia, bacteraemic pneumonia and meningitis among the children of Navarre compared to Majorcan children were 11.8, 2.6 and 0.8, respectively. The risk for less virulent (vaccine serotypes plus 6A, 19A and 23A) and for more virulent serotypes (1 and 7) was 4.9 and 3.1 times higher in Navarre, respectively. The number of 7-valent pneumococcal conjugate vaccine (PCV7) doses administered between 2003 and 2004 were also higher in Navarre. Conversely, antibiotic resistance and paediatric prescriptions for broad-spectrum antibiotics were greater in Majorca. Although the most salient differences between both regions, including the effectiveness of pneumococcal conjugate vaccine in Navarre, appeared to be confounded by the higher frequency of blood cultures taken there, certain differences in serotype composition may be explained by the higher antibiotic consumption in Majorca.

Pérez A, Herranz M, Segura M, Padilla E, Gil F, Durán G, Ferres F, Esteve A, Blanquer D, Bernaola E.

Paediatric Department, Fundación Hospital Manacor, Ctra. Manacor-Alcudia, 07500, Manacor, Islas Baleares, Spain, arperez@hospitalmanacor.org.

Molecular evidence of founder effects of fatal familial insomnia through SNP haplotypes around the D178N mutation.

This work presents a detailed investigation of the genomic region surrounding the PRNP gene in a sample of patients diagnosed with fatal familial insomnia (FFI) from several European countries, notably Spain. The main focus of the study was to explore the origins of the chromosomes carrying the D178N mutation by designing a single-nucleotide polymorphism (SNP) haplotype around the PRNP gene. Haplotypes were constructed by genotyping six SNPs (rs2756271, rs13040327, rs6037932, rs13045348, rs6116474, and rs6116475) in 25 FFI patients from all over Spain. To augment the geographical scope of our study, 13 further FFI cases from Germany (9) and Italy (4) were also examined. Genotyping of SNPs in conjunction with the analysis of genealogical data for a group of FFI patients revealed the existence of two distinct haplotypes potentially associated with the D178N mutation. Of them, GCATTA-M proved to be the common haplotype of Spanish patients, whereas ACATTA-M was typical of the German cases. It is interesting to note that both haplotypes were identified in the Italian samples: GCATTA-M in a family from the Tuscany region and ACATTA-M in a family from the Veneto region. Our findings suggest the occurrence of two independent D178N-129M mutational events in Europe, preserved and transmitted from one generation to the next until nowadays. Likewise, results based on the analysis of SNP data indicate that previous hypotheses postulating that the D178N mutation had independent origins for each family and that its global distribution was determined by recurrent mutational events must be regarded with caution.

Rodríguez-Martínez AB, Alfonso-Sánchez MA, Peña JA, Sánchez-Valle R, Zerr I, Capellari S, Calero M, Zarranz JJ, de Pancorbo MM.

Departamento de Zoología y Biología Celular, Facultad de Farmacia, Universidad del País Vasco, 01006, Vitoria-Gasteiz, Alava, Spain.

Health behaviors of Australian colorectal cancer survivors, compared with noncancer population controls.

GOAL: A better understanding of health behaviors after a cancer diagnosis is important, as these behaviors are related to physical functioning, disease recurrence, development of second primary cancers, and risk of other chronic diseases. Body weight and health behaviors (smoking status, alcohol consumption, and physical activity) were examined in a population-based sample of colorectal cancer survivors and compared to a matched population group. MATERIALS AND METHODS: Data were collected by telephone interviews pre-diagnosis (retrospectively reported), 6 and 12 months post-diagnosis for colorectal cancer survivors (n = 1,250). Comparison data were from a population-based cancer risk survey (n = 6,277). RESULTS: Colorectal cancer survivors were most likely to be overweight/obese pre-diagnosis (66%) than at 6 months (54%) or 12 months post-diagnosis (61%). There was little variation from 6 to 12 months in the proportion of current smokers (7% and 8%, respectively) or high-risk drinkers (both 22%). The greatest changes were for physical activity, with 53% of survivor\’s sufficiently active pre-diagnosis, 32% at 6 months, and 38% at 12 months post-diagnosis. At 12 months, colorectal cancer survivors were more likely than the comparison group to be: underweight (OR = 2.14, 95% CI = 1.38-3.31); a former smoker (OR = 1.44, 95% CI = 1.26-1.63); a low-risk (OR = 1.25, 95% CI = 1.09-1.44) or high-risk drinker (OR = 1.70, 95% CI = 1.43-2.03); and insufficiently active (OR = 1.57, 95% CI = 1.34-1.83) or inactive (OR = 2.76, 95% CI = 2.39-3.19). However, colorectal cancer survivors were significantly less likely to be a current smoker (OR = 0.68, 95% CI = 0.54-0.85). CONCLUSIONS: Our findings show particular scope for physical activity interventions for colorectal cancer survivors. Improving the general health of cancer survivors should help to decrease morbidity in this population and associated health system expenditure.

Hawkes AL, Lynch BM, Youlden DR, Owen N, Aitken JF.

Viertel Centre for Research in Cancer Control, The Cancer Council Queensland, P.O. Box 201, Spring Hill, Brisbane, 4004, Australia, Anna.Hawkes@gmail.com.

Fermentation of acid hydrolysates from olive-tree pruning debris by Pachysolen tannophilus.

The influence of the type and concentration of acid in the hydrolysis process and its effect on the subsequent fermentation by Pachysolen tannophilus (ATCC 32691) to produce ethanol and xylitol was studied. The hydrolysis experiments were performed using hydrochloric, sulphuric and trifluoroacetic acids in concentrations ranging from 0.1 to 1.0 N, a temperature of 90 degrees C, and a time of 240 min. The fermentation experiments were conducted on a laboratory scale in a batch-culture reactor at pH 4.5 and 30 degrees C. The hydrolysis with the highest acid concentration produced the complete solubilization of hemicellulose to monosaccharides. The highest values for the specific rate of ethanol production were registered in cultures hydrolyzed with trifluoroacetic acid, and values were found to decrease as the acid concentration increased. The highest values of overall ethanol yields ( [Formula: see text] = 0.37 kg kg(-1)) were also found in the fermentation of the hydrolysates of trifluoroacetic acid.

Moya AJ, Bravo V, Mateo S, Sánchez S.

Department of Chemical, Environmental and Materials Engineering, University of Jaén, 23071, Jaen, Spain.

Early spring leaf out enhances growth and survival of saplings in a temperate deciduous forest.

Saplings of many canopy tree species in winter deciduous forests receive the major portion of their light budget for their growing season prior to canopy closure in the spring. This period of high light may be critical for achieving a positive carbon (C) gain, thus contributing strongly to their growth and survival. This study of saplings of Aesculus glabra and Acer saccharum in Trelease Woods, Illinois, USA, tested this hypothesis experimentally by placing tents of shade cloth over saplings during their spring period of high light prior to canopy closure in three consecutive years. Leaf senescence began 16 days (year 0) and 60 days (year 1) earlier for shaded A. glabra saplings than control saplings. No change in senescence occurred for A. saccharum. The annual absolute growth in stem diameter of both species was negligible or negative for shaded saplings, but positive for control saplings. Only 7% of the shaded A. glabra saplings were alive after 2 years, while all control saplings survived for 3 years; only 20% of the shaded A. saccharum saplings survived for 3 years, while 73% of control saplings were alive after the same period. Early spring leaf out is a critical mechanism that allows the long-term persistence of saplings of these species in this winter deciduous forest. Studies and models of C gain, growth, and survival of saplings in deciduous forests may need to take into account their spring phenology because saplings of many species are actually \”sun\” individuals in the spring prior to their longer period in the summer shade.

Augspurger CK.

Department of Plant Biology, University of Illinois, Urbana, IL, 61801, USA, carolaug@uiuc.edu.

Nitrogen preferences and plant-soil feedbacks as influenced by neighbors in the alpine tundra.

Plant resource partitioning of chemical forms of nitrogen (N) may be an important factor promoting species coexistence in N-limited ecosystems. Since the microbial community regulates N-form transformations, plant partitioning of N may be related to plant-soil feedbacks. We conducted a (15)N tracer addition experiment to study the ability of two alpine plant species, Acomastylis rossii and Deschampsia caespitosa, to partition organic and inorganic forms of N. The species are codominant and associated with strong plant-soil feedbacks that affect N cycling. We manipulated interspecific interactions by removing Acomastylis or Deschampsia from areas where the species were codominant to test if N uptake patterns varied in the presence of the other species. We found that Deschampsia acquired organic and inorganic N more rapidly than Acomastylis, regardless of neighbor treatment. Plant N uptake-specifically ammonium uptake-increased with plant density and the presence of an interspecific neighbor. Interestingly, this change in N uptake was not in the expected direction to reduce niche overlap and instead suggested facilitation of ammonium use. To test if N acquisition patterns were consistent with plant-soil feedbacks, we also compared microbial rhizosphere extracellular enzyme activity in patches dominated by one or the other species and in areas where they grew together. The presence of both species was generally associated with increased rhizosphere extracellular enzyme activity (five of ten enzymes) and a trend towards increased foliar N concentrations. Taken together, these results suggest that feedbacks through the microbial community, either in response to increased plant density or specific plant neighbors, could facilitate coexistence. However, coexistence is promoted via enhanced resource uptake rather than reduced niche overlap. The importance of resource partitioning to reduce the intensity of competitive interactions might vary across systems, particularly as a function of plant-soil feedbacks.

Ashton IW, Miller AE, Bowman WD, Suding KN.

Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, 92697-2525, USA, iashton@uci.edu.