bluuebunny/crossref_metadata_2025_split huggingface dataset:
Demographic Issues in Longevity Risk Analysis
Authors: Stallard Eric 
Published: December 2006

AbstractFundamental to the modeling of longevity risk is the specification of the assumptions used in demographic forecasting models that are designed to project past experience into future years, with or without modifications based on expert opinion about influential factors not represented in the historical data. Stochastic forecasts are required to explicitly quantify the uncertainty of forecasted cohort survival functions, including uncertainty due to process variance, parameter errors, and model misspecification errors. Current applications typically ignore the latter two sources although the potential impact of model misspecification errors is substantial. Such errors arise from a lack of understanding of the nature and causes of historical changes in longevity and the implications of these factors for the future. This article reviews the literature on the nature and causes of historical changes in longevity and recent efforts at deterministic and stochastic forecasting based on these data. The review reveals that plausible alternative sets of forecasting assumptions have been derived from the same sets of historical data, implying that further methodological development will be needed to integrate the various assumptions into a single coherent forecasting model. Illustrative calculations based on existing forecasts indicate that the ranges of uncertainty for older cohorts' survival functions will be at a manageable level. Uncertainty ranges for younger cohorts will be larger and the need for greater precision will likely motivate further model development.
Fully vs. partially rough implants in maxillary sinus floor augmentation: a randomized‐controlled clinical trial
Authors: Stavropoulos Andreas , Karring Thorkild , Kostopoulos Lambros 
Published: December 2006

AbstractObjectives: To compare implants with a rough surface in their whole length (FR) with implants having a 2 mm coronal machined portion (PR) when used in association with a sinus‐lift procedure.Material and methods: Twenty‐six patients with 2 mm≤x≤9 mm residual alveolar crest were prosthetically restored with implants after a staged sinus‐lift procedure using osteotomes. In 13 randomly chosen patients, no more than one FR implant was placed (test group), while the rest were PR implants. The other 13 patients received only PR implants (control group). For comparisons, only one implant from each patient was used, i.e., from the test group only the 13 FR implants were used, while from the control group, one PR implant was randomly chosen. The presence/absence of plaque, BOP, PPD and REC were registered at the day of delivery of the restorations and after 1 year. Residual alveolar crest height and marginal bone levels around the implants were evaluated on standardized periapical radiographs taken at various stages.Results: Four FR and two PR implants were lost, and the cumulative survival rate was 82.9% (six lost out of 35). There were no significant differences between the two groups. Implant type, residual alveolar crest height, time of osseointegration, time of implant loading and smoking did not seem to influence implant survival.Conclusions: FR and PR implants placed in augmented sinuses did not differ in their clinical performance.
Therapy with hydroxyurea is associated with reduced adhesion molecule gene and protein expression in sickle red cells with a concomitant reduction in adhesive properties
Authors: Gambero Sheley , Canalli Andreia A. , Traina Fabiola , Albuquerque Dulcinéia M. , Saad Sara T.O. , Costa Fernando F. , Conran Nicola 
Published: December 2006

AbstractPropagation of the vaso‐occlusive process in sickle cell anaemia (SCA) is a complex process involving the adhesion of steady–state SCA patients red cells and reticulocytes to the vascular endothelium. The effect of hydroxyurea therapy (HUT) on the adhesive properties of sickle cells and the expression of adhesion molecule genes by erythroid cells of SCA individuals is not yet fully understood. The expressions of the CD36 gene and the VLA‐4‐integrin subunit genes, CD49d (α‐subunit) and CD29 (β‐subunit), were compared in the reticulocytes of steady–state SCA patients and patients on HUT using real‐time PCR. Basal adhesion of red cells from these subjects was also compared using static adhesion assays, as was surface protein expression, using flow cytometry. Basal sickle red cell adhesion to fibronectin was significantly greater than that of normal cells (P < 0.01); in contrast, HUT was associated with significantly lower levels (P < 0.01) of red cell adhesion that were similar to those of control cells; this decrease could not be justified solely by altered reticulocyte numbers in this population. Accordingly, flow cytometry demonstrated that reticulocytes from patients on HUT had significantly lower CD36 and CD49d surface expressions (P < 0.01) and, importantly, significantly lower expressions of the CD36, CD49d and CD29 genes (P < 0.05) than reticulocytes of SCA patients not on HUT. Taken together, data support the hypothesis that HUT reduces the adhesive properties of sickle cells and that this decrease appears to be mediated, at least in part, by a decrease in the gene and, consequently, surface protein expression of adhesion molecules such as VLA‐4 and CD36.
Identification of intracellular oral species within human crevicular epithelial cells from subjects with chronic periodontitis by fluorescence in situ hybridization
Authors: Colombo A. V. , Da Silva C. M. , Haffajee A. , Colombo A. P. V. 
Published: December 2006

Background and Objective:  Interactions between oral bacteria and gingival epithelial cells play an important role in the pathogenesis of periodontal diseases. This study used in situ hybridization with 16 rRNA probes and confocal microscopy to detect the periodontal pathogens Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Tannerella forsythia, and Treponema denticola within epithelial cells from periodontal pockets, gingival crevice, and buccal mucosa collected from subjects with chronic periodontitis (n = 14) and good periodontal health (n = 8).Material and Methods:  Each green fluorescent species‐specific and universal probe was hybridized with all 58 epithelial samples from the 22 patients. The samples were observed by confocal microscopy to confirm the intracellular localization of oral species of bacteria. The mean frequency of detection and number of intracellular bacteria per epithelial cell were computed for each sample.Results:  The frequency of cells with internalized bacteria was higher in samples from the gingival crevice than in samples from the oral mucosa. Epithelial cells from all subjects harbored intracellular bacteria; however, patients with periodontitis presented significantly higher counts of bacteria per cell than periodontally healthy individuals (p < 0.05). Periodontal pathogens showed a trend to be detected in higher numbers in epithelial cells from periodontitis patients. In particular, T. forsythia and T. denticola were significantly more prevalent in periodontal pocket cells than healthy sulci and buccal cell samples in the periodontitis group (p < 0.05).Conclusion:  Those findings indicate that crevicular and buccal cells present internalized bacteria, regardless of periodontal status. However, higher bacterial loads are detected in cells from subjects with periodontitis.
Impact of Elevated PCO2 on Mass Flow of Reduced Nitrogen in Trees†
Authors: Liu Xi‐Ping 
Published: December 2006

AbstractTo analyze the effects of elevated carbon dioxide concentration (PCO2) on the mass flow of reduced nitrogen (N) in the phloem and xylem of trees, juvenile beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.) were grown in phytotrons and exposed to ambient and elevated PCO2 (plus 687.5 mg/m3 CO2) for three growing seasons. Elevated PCO2 significantly decreased the mass flow of N from the shoot to roots of beech by significantly reducing the concentration of soluble amino compounds in the phloem, even if the area of conductive phloem of cross‐sectional bark tissue was significantly increased, because of less callus deposition in the sieve elements. In spruce, the downward mass flow of reduced N also tended to be decreased, similar to that in beech. Resembling findings in the phloem, N mass flow from roots to shoot in both tree species was significantly diminished owing to significantly reduced concentrations of amino compounds in the xylem and a lower transpiration rate. Therefore, the mass flow of reduced N between shoots and roots of trees was mainly governed by the concentrations of soluble amino compounds in the phloem and xylem in relation to the loading of reduced N in both long‐distance transport pathways.(Managing editor: Ya‐Qin Han)
Functional Characterization of Mi, a Root‐knot Nematode Resistance Gene from Tomato (Lycopersicon esculentum L.)
Authors: Chen Ru‐Gang , Zhang Li‐Ying , Zhang Jun‐Hong , Zhang Wei , Wang Xue , Ouyang Bo , Li Han‐Xia , Ye Zhi‐Biao 
Published: December 2006

AbstractRoot‐knot nematodes (Meloidogyne spp.) cause major economic damage to numerous crop species around the world. Plant resistance is the most important attribute that is able to suppress invasion by the root‐knot nematodes. In the present study, a candidate root‐knot nematode resistance gene (Mi) was isolated from the resistant tomato (Lycopersicon esculentum L.) line RN‐1. Expression profiling analysis revealed that this gene was expressed specifically in the roots, stems, and leaves, but not in the flowers or fruits. To verify the real function of this candidate gene, both sense and inteference RNA (RNAi) vectors were constructed. We obtained 31 transgenic plants with between one and seven copies of T‐DNA inserts of sense Mi from two nematode‐susceptible tomato cultivars as assayed by polymerase chain reaction (PCR) and Southern blotting analysis. Reverse transcription‐PCR analysis revealed that expression levels of the Mi gene varied in different transgenic plants. Nematode assays showed that the resistance to root‐knot nematodes was significantly improved in some transgenic lines compared with untransformed susceptible controls and that the resistance was heritable in selfed progeny. Loss of function via RNAi further confirmed the role of the Mi gene and the original resistant lines became susceptible to root‐knot nematodes.(Managing editor: Li‐Hui Zhao)
Rice Mitochondrial Genes Are Transcribed by Multiple Promoters That Are Highly Diverged
Authors: Zhang Qun‐Yu , Liu Yao‐Guang 
Published: December 2006

AbstractPlant mitochondrial genes are often transcribed into complex sets of mRNA. To characterize the transcription initiation and promoter structure, the transcript termini of four mitochondrial genes, atp1, atp6, cob, rps7, in rice (Oryza sativa L.), were determined by using a modified circularized RNA reverse transcription‐polymerase chain reaction method. The results revealed that three genes (atp1, atp6, rps7) were transcribed from multiple initiation sites, indicating the presence of multiple promoters. Two transcription termination sites were detected in three genes (atp6, cob, rps7), respectively. Analysis on the promoter architecture showed that the YRTA (Y=T or C, R=A or G) motifs that are widely present in the mitochondrial promoters of other monocotand dicot plant species were detected only in two of the 12 analyzed promoters. Our data suggest that the promoter sequences in the rice mitochondrial genome are highly diverged in comparison to those in other plants, and the YRTA motif is not an essential element for the promoter activity.(Managing editor: Li‐Hui Zhao)
Photosynthetic Properties of Photosystem II in Arabidopsis thaliana Ipa1 Mutant
Authors: Peng Lian‐Wei , Guo Jin‐Kui , Ma Jin‐Fang , Chi Wei , Zhang Li‐Xin 
Published: December 2006

AbstractIn a previous study, we characterized a high chlorophyll fluorescence Ipa1 mutant of Arabidopsis thaliana, in which approximately 20% photosystem (PS) II protein is accumulated. In the present study, analysis of fluorescence decay kinetics and thermoluminescence profiles demonstrated that the electron transfer reaction on either the donor or acceptor side of PSII remained largely unaffected in the Ipa1 mutant. In the mutant, maximal photochemical efficiency (Fv/Fm, where Fm is the maximum fluorescence yield and Fv is variable fluorescence) decreased with increasing light intensity and remained almost unchanged in wild‐type plants under different light conditions. The Fv/Fm values also increased when mutant plants were transferred from standard growth light to low light conditions. Analysis of PSII protein accumulation further confirmed that the amount of PSII reaction center protein is correlated with changes in Fv/Fm in Ipa1 plants. Thus, the assembled PSII in the mutant was functional and also showed increased photosensitivity compared with wild‐type plants.(Managing editor: Ping He)
Muscle Tuning During Running: Implications of an Un-tuned Landing
Authors: Boyer Katherine A. , Nigg Benno M. 
Published: December 2006

AbstractBackground: The impact force in heel-toe running is an input signal into the body that initiates vibrations of the soft tissue compartments of the leg. These vibrations are heavily damped and the paradigm of muscle tuning suggests the body adapts to different input signals to minimize these vibrations. The objectives of the present study were to investigate the implications of not tuning a muscle properly for a landing with a frequency close to the resonance frequency of a soft tissue compartment and to look at the effect of an unexpected surface change on the subsequent step of running. Method: Thirteen male runners were recruited and performed heel-toe running over two surface conditions. The peak accelerations and biodynamic responses of the soft tissue compartments of the leg along with the EMG activity of related muscles were determined for expected soft, unexpected hard and expected hard landings. Results and Conclusions: For the unexpected hard landing there was a change in the input frequency of the impact force, shifting it closer to the resonance frequency of the soft tissue compartments. For the unexpected landing there was no muscle adaptation, as subjects did not know the running surface was going to change. In support of the muscle-tuning concept an increase in the soft tissue acceleration did occur. This increase was greater when the proximity of the input signal frequency was closer to the resonance frequency of the soft tissue compartment. Following the unexpected change in the input signal a change in pre-contact muscle activity to minimize soft tissue compartment vibrations was not found. This suggests if muscle tuning does occur it is not a continuous feedback response that occurs with every small change in the landing surface properties. In previous studies with significant adaptation periods to new input signals significant correlations between the changes in the input signal frequency and the EMG intensity have been shown, however, changes in soft tissue accelerations have not been found. The results of the present study showed that changes in these soft tissue accelerations can occur in response to a resonance frequency input signal when a muscle reaction has not happened.
Protection of Mice from Lethal
Escherichia coli
Infection by ChimericHuman Bactericidal/Permeability-Increasing Protein and ImmunoglobulinG1 Fc Gene Delivery
Authors: Chen Jindong , Li Chengyao , Guan Yuanzhi , Kong Qingli , Li Chen , Guo Xianghua , Chen Qinghua , Jing Xuefang , Lv Zhe , An Yunqing 
Published: December 2006

ABSTRACT

To
evaluate the potentiality of applying gene therapy to bacterial
infections, especially for preventing infection in high-risk patients,
we investigated protection of mice from challenge with lethal
Escherichia coli
infection by adeno-associated virus serotype
2 (AAV2)-mediated gene transfer of a chimeric
BPI
23
-Fcγ1 gene, which consisted of human
bactericidal/permeability-increasing protein (BPI) gene encoding the
functional N terminus (amino acid residues 1 to 199) of human BPI and
an Fcγ1 gene encoding the Fc segment of human immunoglobulin
G1. Here we show that the target protein that was expressed and
secreted into the serum of the gene-transferred mice demonstrated the
activity of a neutralizing endotoxin, killing
E. coli
and
mediating opsonization. After lethal
E. coli
infection, the
count of bacteria and the levels of endotoxin and proinflammatory
cytokines in the gene-transferred mice were decreased. The survival
rate of BPI
23
-Fcγ1 gene-transferred mice markedly
increased, especially in conjunction with antibiotics. Our data suggest
that AAV2-mediated chimeric BPI
23
-Fcγ1 gene delivery
could potentially be used clinically for the protection and treatment
of infection with gram-negative bacteria in high-risk
individuals.
Moxifloxacin, Ofloxacin, Sparfloxacin, and Ciprofloxacin against
Mycobacterium tuberculosis
: Evaluation of In Vitro and Pharmacodynamic Indices That Best Predict In Vivo Efficacy
Authors: Shandil Radha K. , Jayaram Ramesh , Kaur Parvinder , Gaonkar Sheshagiri , Suresh B. L. , Mahesh B. N. , Jayashree R. , Nandi Vrinda , Bharath Sowmya , Balasubramanian V. 
Published: December 2006

ABSTRACT

Members of the fluoroquinolone class are being actively evaluated for inclusion in tuberculosis chemotherapy regimens, and we sought to determine the best in vitro and pharmacodynamic predictors of in vivo efficacy in mice. MICs for
Mycobacterium tuberculosis
H37Rv were 0.1 mg/liter (sparfloxacin [SPX]) and 0.5 mg/liter (moxifloxacin [MXF], ciprofloxacin [CIP], and ofloxacin [OFX]). The unbound fraction in the presence of murine serum was concentration dependent for MXF, OFX, SPX, and CIP. In vitro time-kill studies revealed a time-dependent effect, with the CFU reduction on day 7 similar for all four drugs. However, with a J774A.1 murine macrophage tuberculosis infection model, CIP was ineffective at up to 32× MIC. In addition, MXF, OFX, and SPX exhibited less activity than had been seen in the in vitro time-kill study. After demonstrating that the area under the concentration-time curve (AUC) and maximum concentration of drug in plasma were proportional to the dose in vivo, dose fractionation studies with total oral doses of 37.5 to 19,200 mg/kg of body weight (MXF), 225 to 115,200 mg/kg (OFX), 30 to 50,000 mg/kg (SPX), and 38 to 100,000 mg/kg (CIP) were performed with a murine aerosol infection model. MXF was the most efficacious agent (3.0 ± 0.2 log
10
CFU/lung reduction), followed by SPX (1.4 ± 0.1) and OFX (1.5 ± 0.1). CIP showed no effect. The ratio of the AUC to the MIC was the pharmacodynamic parameter that best described the in vivo efficacy. In summary, a lack of intracellular killing predicted the lack of in vivo activity of CIP. The in vivo rank order for maximal efficacy of the three active fluoroquinolones was not clearly predicted by the in vitro assays, however.
Length Effects in Antimicrobial Peptides of the (RW)nSeries
Authors: Liu Zhigang , Brady Anna , Young Anne , Rasimick Brian , Chen Kang , Zhou Chunhui , Kallenbach Neville R. 
Published: December 2006

ABSTRACTA class of antimicrobial peptides involved in host defense consists of sequences rich in Arg and Trp-R and -W. Analysis of the pharmacophore in these peptides revealed that chains as short as trimers of sequences such as WRW and RWR have antimicrobial activity (M. B. Strom, B. E. Haug, M. L. Skar, W. Stensen, T. Stiberg, and J. S. Svendsen, J. Med. Chem. 46:1567-1570, 2003). To evaluate the effect of chain length on antimicrobial activity, we synthesized a series of peptides containing simple sequence repeats, (RW)n-NH2(wherenequals 1, 2, 3, 4, or 5), and determined their antimicrobial and hemolytic activity. The antimicrobial activity of the peptides increases with chain length, as does the hemolysis of red blood cells. Within the experimental error, longer peptides (nequals 3, 4, or 5) show similar values for the ratio of hemolytic activity to antibacterial activity, or the hemolytic index. The (RW)3represents the optimal chain length in terms of the efficacy of synthesis and selectivity as evaluated by the hemolytic index. Circular dichroism spectroscopy indicates that these short peptides appear to be unfolded in aqueous solution but acquire structure in the presence of phospholipids. Interaction of the peptides with model lipid vesicles was examined using tryptophan fluorescence. The (RW)npeptides preferentially interact with bilayers containing the negatively charged headgroup phosphatidylglycerol relative to those containing a zwitterionic headgroup, phosphatidylcholine.
Cathepsin A Is the Major Hydrolase Catalyzing the Intracellular Hydrolysis of the Antiretroviral Nucleotide Phosphonoamidate Prodrugs GS-7340 and GS-9131
Authors: Birkus Gabriel , Wang Ruth , Liu Xiaohong , Kutty Nilima , MacArthur Holly , Cihlar Tomas , Gibbs Craig , Swaminathan Swami , Lee William , McDermott Martin 
Published: December 2006

ABSTRACTGS-7340 and GS-9131 {9-[(R)-2-[[(S)-[[(S)-1-(isopropoxycarbonyl)ethyl]amino]phenoxyphosphinyl]methoxy]-propyl]adenine and 9-(R)-4′-(R)-[[[(S)-1-[(ethoxycarbonyl)ethyl]amino]phenoxyphosphinyl]methoxy]-2′-fluoro-1′-furanyladenine, respectively} are novel alkylalaninyl phenyl ester prodrugs of tenofovir {9-R-[(2-phosphonomethoxy)propyl]adenine} (TFV) and a cyclic nucleotide analog, GS-9148 (phosphonomethoxy-2′-fluoro-2′, 3′-dideoxydidehydroadenosine), respectively. Both prodrugs exhibit potent antiretroviral activity against both wild-type and drug-resistant human immunodeficiency virus type 1 strains and excellent in vivo pharmacokinetic properties. In this study, the main enzymatic activity responsible for the initial step in the intracellular activation of GS-7340 and GS-9131 was isolated from human peripheral blood mononuclear cells and identified as lysosomal carboxypeptidase A (cathepsin A [CatA]; EC 3.4.16.5). Biochemical properties of the purified hydrolase (native complex and catalytic subunit molecular masses of 100 and 29 kDa, respectively; isoelectric point [pI] of 5.5) matched those of CatA. Recombinant CatA and the isolated prodrug hydrolase displayed identical susceptibilities to inhibitors and identical substrate preferences towards a panel of tenofovir phosphonoamidate prodrugs. Incubation of both enzymes with14C-labeled GS-7340 or [3H]difluorophosphonate resulted in the covalent labeling of identical 29-kDa catalytic subunits. Finally, following a 4-h incubation with GS-7340 and GS-9131, the intracellular concentrations of prodrug metabolites detected in CatA-negative fibroblasts were approximately 7.5- and 3-fold lower, respectively, than those detected in normal control fibroblasts. Collectively, these data demonstrate the key role of CatA in the intracellular activation of nucleotide phosphonoamidate prodrugs and open new possibilities for further improvement of this important class of antiviral prodrugs.
Plasmid-Mediated KPC-2 in a
Klebsiella pneumoniae
Isolate from China
Authors: Wei Ze-Qing , Du Xiao-Xing , Yu Yun-Song , Shen Ping , Chen Ya-Gang , Li Lan-Juan 
Published: December 2006

ABSTRACT

A carbapenem-resistant isolate of
Klebsiella pneumoniae
producing class A carbapenemase KPC-2 was identified in Zhejiang, China. The KPC-2 gene was located on an approximately 60-kb plasmid in a genetic environment partially different from that of
bla
KPC-2
in the isolates from the United States and Colombia.