bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Mutation in Murine Hepatitis Virus nsp5, the Viral 3C-Like Proteinase, Causes Temperature-Sensitive Defects in Viral Growth and Protein Processing
Authors: Sparks Jennifer S. , Donaldson Eric F. , Lu Xiaotao , Baric Ralph S. , Denison Mark R. 
Published: April 2008

ABSTRACT

Sequencing and reversion analysis of murine hepatitis virus (MHV) temperature-sensitive (
ts
) viruses has identified putative
ts
mutations in the replicase nonstructural proteins (nsp's) of these coronaviruses. In this study, reverse transcriptase PCR sequencing of the RNA genome of an isolate of the MHV
ts
virus Alb
ts
6, referred to as Alb/ts/nsp5/V148A, identified a putative
ts
mutation in nsp5 (T10651C, Val148Ala), the viral 3C-like proteinase (3CLpro). The introduction of the T10651C mutation into the infectious MHV clone resulted in the recovery of a mutant virus, the nsp5/V148A virus, that demonstrated reduced growth and nsp5 proteinase activity identical to that of Alb/ts/nsp5/V148A at the nonpermissive temperature. Sequence analysis of 40°C revertants of Alb/ts/nsp5/V148A identified primary reversion to Ala148Val in nsp5, as well as two independent second-site mutations resulting in Ser133Asn and His134Tyr substitutions in nsp5. The introduction of the Ser133Asn or His134Tyr substitution into the cloned nsp5/V148A mutant virus background resulted in the recovery of viruses with increased growth fitness and the partial restoration of nsp5 activity at the nonpermissive temperature. Modeling of the nsp5 structure of Alb/ts/nsp5/V148A predicted that the Val148Ala mutation alters residue 148 interactions with residues of the substrate binding S1 subsite of the nsp5 active-site cavity. This study identifies novel residues in nsp5 that may be important for regulating substrate specificity and nsp5 proteinase activity.
Comprehensive Immunological Evaluation Reveals Surprisingly Few Differences between Elite Controller and ProgressorMamu-B*17-Positive Simian Immunodeficiency Virus-Infected Rhesus Macaques
Authors: Maness Nicholas J. , Yant Levi J. , Chung Chungwon , Loffredo John T. , Friedrich Thomas C. , Piaskowski Shari M. , Furlott Jessica , May Gemma E. , Soma Taeko , León Enrique J. , Wilson Nancy A. , Piontkivska Helen , Hughes Austin L. , Sidney John , Sette Alessandro , Watkins David I. 
Published: April 2008

ABSTRACTThe association between particular major histocompatibility complex class I (MHC-I) alleles and control of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) replication implies that certain CD8+T-lymphocyte (CD8-TL) responses are better able than others to control viral replication in vivo. However, possession of favorable alleles does not guarantee improved prognosis or viral control. In rhesus macaques, the MHC-I alleleMamu-B*17is correlated with reduced viremia and is overrepresented in macaques that control SIVmac239, termed elite controllers (ECs). However, there is so far no mechanistic explanation for this phenomenon. Here we show that the chronic-phase Mamu-B*17-restricted repertoire is focused primarily against just five epitopes—VifHW8, EnvFW9, NefIW9, NefMW9, andenvARFcRW9—in both ECs and progressors. Interestingly, Mamu-B*17-restricted CD8-TL do not target epitopes in Gag. CD8-TL escape variation occurred in all targeted Mamu-B*17-restricted epitopes. However, recognition of escape variant peptides was commonly observed in both ECs and progressors. Wild-type sequences in the VifHW8 epitope tended to be conserved in ECs, but there was no evidence that this enhances viral control. In fact, no consistent differences were detected between ECs and progressors in any measured parameter. Our data suggest that the narrowly focused Mamu-B*17-restricted repertoire suppresses virus replication and drives viral evolution. It is, however, insufficient in the majority of individuals that express the “protective” Mamu-B*17 molecule. Most importantly, our data indicate that the important differences betweenMamu-B*17-positive ECs and progressors are not readily discernible using standard assays to measure immune responses.
Human Immunodeficiency Virus Type 1 Vpr Binds to the N Lobe of the Wee1 Kinase Domain and Enhances Kinase Activity for Cdc2
Authors: Kamata Masakazu , Watanabe Nobumoto , Nagaoka Yoshiko , Chen Irvin S. Y. 
Published: April 2008

ABSTRACT

Human immunodeficiency virus type 1 Vpr is a virion-associated accessory protein that has multiple activities within an infected cell. One of the most dramatic effects of Vpr is the induction of cell cycle arrest at the G
2
/M boundary, followed by apoptosis. This effect has implications for CD4
+
cell loss in AIDS. In normal cell cycle regulation, Wee1, a key regulator for G
2
-M progression, phosphorylates Tyr15 on Cdc2 and thereby blocks the progression of cells into M phase. We demonstrate that Vpr physically interacts with Wee1 at the N lobe of the kinase domain analogous to that present in other kinases. This interaction with Vpr enhances Wee1 kinase activity for Cdc2. Overexpression of Wee1 kinase-deficient mutants competes for Vpr-mediated cell cycle arrest, and deletion of the region of Wee1 that binds Vpr abrogates that competition. However, the Vpr mutants I74P and I81P, which fail to induce G
2
arrest, can bind to and increase the kinase activity of Wee1 to the same extent as wild-type Vpr. Therefore, we conclude that the binding of Vpr to Wee1 is not sufficient for Vpr to activate the G
2
checkpoint, and it may reflect an independent function of Vpr.
Tumor Antigen LRRC15 Impedes Adenoviral Infection: Implications for Virus-Based Cancer Therapy
Authors: O'Prey Jim , Wilkinson Simon , Ryan Kevin M. 
Published: April 2008

ABSTRACT
Adenoviruses for gene or oncolytic therapy are under development. Notable among these strategies is adenoviral delivery of the tumor suppressor p53. Since all therapeutics have limitations in certain settings, we have undertaken retroviral suppressor screens to identify genes conferring resistance to adenovirus-delivered p53. These studies identified the tumor antigen LRRC15, which is frequently overexpressed in multiple tumor types, as a repressor of cell death due to adenoviral p53. LRRC15, however, does not impede p53 function per se but impedes adenoviral infection. Specifically, LRRC15 causes redistribution of the coxsackievirus-adenovirus receptor away from the cell surface. This effect is manifested in less adenoviral binding to the surfaces of LRRC15-expressing cells. This discovery, therefore, not only is important for understanding adenoviral biology but also has potentially important implications for adenovirus-based anticancer therapeutics.
Structural and Functional Constraints Limit Options for Cytotoxic T-Lymphocyte Escape in the Immunodominant HLA-B27-Restricted Epitope in Human Immunodeficiency Virus Type 1 Capsid
Authors: Schneidewind Arne , Brockman Mark A. , Sidney John , Wang Yaoyu E. , Chen Huabiao , Suscovich Todd J. , Li Bin , Adam Rahma I. , Allgaier Rachel L. , Mothé Bianca R. , Kuntzen Thomas , Oniangue-Ndza Cesar , Trocha Alicja , Yu Xu G. , Brander Christian , Sette Alessandro , Walker Bruce D. , Allen Todd M. 
Published: April 2008

ABSTRACTControl of human immunodeficiency virus type 1 (HIV-1) by HLA-B27-positive subjects has been linked to an immunodominant CD8+cytotoxic T-lymphocyte (CTL) response targeting the conserved KK10 epitope (KRWIILGLNK263-272) in p24/Gag. Viral escape in KK10 typically occurs through development of an R264K substitution in conjunction with the upstream compensatory mutation S173A, and the difficulty of the virus to escape from the immune response against the KK10 epitope until late in infection has been associated with slower clinical progression. Rare alternative escape mutations at R264have been observed, but factors dictating the preferential selection of R264K remain unclear. Here we illustrate that while all observed R264mutations (K, G, Q, and T) reduced peptide binding to HLA-B27 and impaired viral replication, the replicative defects of the alternative mutants were actually less pronounced than those for R264K. Importantly, however, none of these mutants replicated as well as an R264K variant containing the compensatory mutation S173A. In assessing the combined effects of viral replication and CTL escape using an in vitro coculture assay, we further observed that the compensated R264K mutant also displayed the highest replication capacity in the presence of KK10-specific CTLs. Comparisons of codon usage for the respective variants indicated that generation of the R264K mutation may also be favored due to a G-to-A bias in nucleotide substitutions during HIV-1 replication. Together, these data suggest that the preference for R264K is due primarily to the ability of the S173A-compensated virus to replicate better than alternative variants in the presence of CTLs, suggesting that viral fitness is a key contributor for the selection of immune escape variants.
A Direct Comparison of Human Papillomavirus Type 16 L1 Particles Reveals a Lower Immunogenicity of Capsomeres than Viruslike Particles with Respect to the Induced Antibody Response
Authors: Thönes Nadja , Herreiner Anna , Schädlich Lysann , Piuko Konrad , Müller Martin 
Published: April 2008

ABSTRACTCapsomeres are considered to be an alternative to viruslike particle (VLP)-based vaccines as they can be produced in prokaryotic expression systems. So far, no detailed side-by-side comparison of VLPs and capsomeres has been performed. In the present study, we immunized mice with insect cell-derived human papillomavirus type 16 VLPs and capsomeres. VLPs induced consistently higher antibody titers than capsomeres but the two forms induced similar CD8 T-cell responses after subcutaneous, intranasal, and oral immunization, and at least 20 to 40 times more L1 in the form of capsomeres than in the form of VLPs was needed to achieve comparable antibody responses. These results were confirmed by DNA immunization. The lower immunogenicity of capsomeres was independent of the isotype switch, as it was also observed for the early immunoglobulin M responses. Although there were differences in the display of surface epitopes between the L1 particles, these did not contribute significantly to the differences in the immune responses. capsomeres were less immunogenic than VLPs in Toll-like receptor 4 (TLR4)-deficient mice, suggesting that the lower immunogenicity is not due to a failure of capsomeres to trigger TLR4. We observed better correlation between antibody results from enzyme-linked immunosorbent assays and neutralization assays for sera from VLP-immunized mice than for sera from capsomere-immunized mice, suggesting qualitative differences between VLPs and capsomeres. We also showed that the lower immunogenicity of capsomeres could be compensated by the use of an adjuvant system containing MPL. Taken together, these results suggest that, presumably because of the lower degree of complexity of the antigen organization, capsomeres are significantly less immunogenic than VLPs with respect to the humoral immune response and that this characteristic should be considered in the design of putative capsomere-based prophylactic vaccines.
Identification of a Highly Conserved, Functional Nuclear Localization Signal within the N-Terminal Region of Herpes Simplex Virus Type 1 VP1-2 Tegument Protein
Authors: Abaitua F. , O'Hare P. 
Published: April 2008

ABSTRACT
VP1-2 is a large structural protein assembled into the tegument compartment of the virion, conserved across the herpesviridae, and essential for virus replication. In herpes simplex virus (HSV) and pseudorabies virus, VP1-2 is tightly associated with the capsid. Studies of its assembly and function remain incomplete, although recent data indicate that in HSV, VP1-2 is recruited onto capsids in the nucleus, with this being required for subsequent recruitment of additional structural proteins. Here we have developed an antibody to characterize VP1-2 localization, observing the protein in both cytoplasmic and nuclear compartments, frequently in clusters in both locations. Within the nucleus, a subpopulation of VP1-2 colocalized with VP26 and VP5, though VP1-2-positive foci devoid of these components were observed. We note a highly conserved basic motif adjacent to the previously identified N-terminal ubiquitin hydrolase domain (DUB). The DUB domain in isolation exhibited no specific localization, but when extended to include the adjacent motif, it efficiently accumulated in the nucleus. Transfer of the isolated motif to a test protein, β-galactosidase, conferred specific nuclear localization. Substitution of a single amino acid within the motif abolished the nuclear localization function. Deletion of the motif from intact VP1-2 abrogated its nuclear localization. Moreover, in a functional assay examining the ability of VP1-2 to complement growth of a VP1-2-ve mutant, deletion of the nuclear localization signal abolished complementation. The nuclear localization signal may be involved in transport of VP1-2 early in infection or to late assembly sites within the nucleus or, considering the potential existence of VP1-2 cleavage products, in selective localization of subdomains to different compartments.
Association between walking distance and percentiles of body mass index in older and younger men
Authors: Williams P T 
Published: April 2008

Objective:To assess the association of weekly walking distance to body weight and waist circumference in elderly (age ⩾75 years), senior (55⩽ age <75 years), middle-aged (35⩽ age <55 years), and younger men (18⩽ age <35 years old).Design:Cross-sectional analyses of baseline questionnaires from 7082 male participants of the National Walkers’ Health Study.Results:Standard regression analyses showed that body mass index (BMI) was inversely and significantly associated with walking distance (kg/m2per km/week) in elderly (slope (SE): −0.032 (0.008)), senior (−0.045 (0.005)) and middle-aged men (−0.037 (0.007)), as were their waist circumferences (−0.090 (0.025), −0.122 (0.012) and −0.091 (0.015) cm per km/week, respectively), and that these slopes remained significant when adjusted statistically for reported weekly servings of meat, fish, fruit and alcohol. However, percentile regression analyses showed that the declines in BMI per km/week walked were greater at the higher than the lower percentiles of the BMI distribution. In men ⩾74 years old the decline per km walked was 4.9-fold greater among the heaviest men (that is, 90th BMI percentile; −0.076 kg/m2per km/week) than among the leanest men (that is, 10th BMI percentile; −0.015 kg/m2per km/week). The differences in slope at the 90th compared to the 10th BMI percentile were 5.4-fold among men 55–74 years old and sixfold among men 35–54 years old. Per km/week walked, the declines at the 90th percentile of waist circumference were also greater than at its 10th percentile, and intermediate for percentiles in between. Whereas standard regression analyses suggest that the average declines in BMI per km/week walked reported here are consistent with those reported previously per km/week run in male runners 35–54 years old (−0.036 (0.001) kg/m2per km/week) and ⩾50 years old (−0.038 (0.001) kg/m2per km/week), percentile regression analyses showed that when adjusted to the leaner body weights of the runners the declines per km walked were between 49% and 59% less for walkers than runners.Conclusions:Declines in BMI and waist circumferences with walking distance depend upon the percentile of the BMI distribution, with the decline per km walked being significantly greater among heavier men.
Regular Tai Chi Chuan exercise improves T cell helper function of patients with type 2 diabetes mellitus with an increase in T-bet transcription factor and IL-12 production
Authors: Yeh S-H , Chuang H , Lin L-W , Hsiao C-Y , Wang P-W , Liu R-T , Yang K D 
Published: April 2008

Background:Exercise has been shown to be beneficial in the treatment of type 2 diabetes mellitus (DM); its benefit to immune function, however, remains to be determined.Objective:This study investigated the effect of a 12-week course of Tai Chi Chuan (TCC) exercise on T cell helper (Th) reaction in patients with type 2 DM.Methods:A case-control study was performed in 30 pairs of patients with type 2 DM and normal age-matched adults. Fasting blood glucose, HbA1c, mediators (interleukin (IL)-12, IL-4 and transforming growth factor (TGF)β) and transcription factors (T-bet, GATA-3 and FoxP3) of Th1/Th2/T regulatory (Treg) reaction were measured before and after a 12-week TCC exercise programme.Results:Fasting glucose and HbA1c levels in the patients with type 2 DM were significantly higher than in age-matched controls before exercise. After TCC exercise, HbA1c levels in patients with type 2 DM significantly decreased (7.59 (0.32)% vs 7.16 (0.22)%; p = 0.047) and blood levels of IL-12 increased significantly (5.96 (1.10) vs 12.96 (3.07); p = 0.035). To study the molecular Th1/Th2/Treg reaction, patients with type 2 DM were found to have lower T-bet but not GATA-3 or FoxP3 expression than normal controls before TCC exercise. After the 12-week TCC exercise T-bet expression significantly increased in patients with type 2 DM.Conclusions:A 12-week TCC exercise programme decreases HbA1c levels along with an increase in the Th1 reaction. A combination of TCC with medication may provide an even better improvement in both metabolism and immunity of patients with type 2 DM.
Comparison of fat oxidation during exercise in lean and obese pubertal boys: clinical implications
Authors: Zunquin G , Theunynck D , Sesboüé B , Arhan P , Bouglé D 
Published: April 2008

Objective:To examine fat oxidation rates during exercise in lean and obese pubescent children.Design:A graded leg cycle ergometry test was performed by two groups of pubescent boys (13 lean: mean (SD) age 12.0 (0.5) years, body mass index (BMI) 18.56 (1.12) kg/m2; 17 obese: mean (SD) age 12.1 (0.1) years, BMI 26.68 (3.37) kg/m2; p<0.001). The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. The mean ventilatory gas measurement was obtained during the last 30 s of each step for calculation of fat oxidation rate vs exercise intensity.Results:At low intensity (0–30% of peak oxygen consumption) when fat-free mass is considered, the fat oxidation rate was identical for the two groups. At higher intensities (40%, 50% and 60% of peak oxygen consumption) the fat oxidation rate was significantly higher in lean boys than in obese boys.Conclusion:These results confirm that obese pubertal boys have fat-free mass decreased capacities to use fat during moderate exercise. The findings suggest that obese boys need to practise physical activity at a lower intensity than healthy boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.
Randomized controlled trial of ionization and photoelectric smoke alarm functionality
Authors: Mueller B A , Sidman E A , Alter H , Perkins R , Grossman D C 
Published: April 2008

Objective:To compare functionality, reasons for non-function, and nuisance alarm levels of two common types of smoke alarms after installation in low- to mid-level income households in King County, Washington.Methods:Randomized controlled trial of 761 households. An ionization or photoelectric smoke alarm was installed between June 1, 2000 and July 31, 2002. Main outcome measures were: percentage of study alarms that were working, observed reasons for non-functional status, and self-reported frequency of nuisance alarms at 9 and 15 months of follow-up.Results:At 9 months after installation, 20% of ionization, vs 5% of photoelectric alarms were non-functional, a difference that persisted at 15 months, with the most common reasons for both types being a disconnected or absent battery. The risk ratio for ionization, relative to photoelectric alarms, being non-functional or removed was 2.7 (95% CI 1.8 to 4.1) at 15 months of follow-up. These findings were not altered by educational level, or the presence of smokers, children <5 years, or adults ⩾65 years.Conclusions:Burn prevention efforts are geared towards increasing smoke alarm ownership and improving maintenance of functional status. Results suggest that the selective use of photoelectric alarms by fire injury prevention programs or consumers may provide longer-term protection in similar populations. Designing smoke alarms that minimize nuisance alarming may also result in longer term functionality.
Feasibility of standardized injury surveillance and reporting: a comparison of data from four Asian nations
Authors: Nakahara S , Jayatilleke A U , Ichikawa M , Marasinghe A , Kimura A , Yoshida K 
Published: April 2008

Background:To address the increasing number of injuries in developing countries, the World Health Organization (WHO) encourages the establishment of hospital-based surveillance systems and systematic data collection. Although a computerized system is preferable in terms of efficiency, many developing countries have difficulty accessing the appropriate resources.Objectives:To assess the possibility of comparing and sharing data among countries, and then to discuss the possibility of establishing an international data management system through the internet.Methods:A point-by-point comparison of data directories from injury surveillance systems in Thailand, Cambodia, Sri Lanka, and Japan was conducted using guidelines published by WHO as the standard.Results:Thailand, Cambodia, and Sri Lanka used data items that are comparable to each other and to WHO guidelines, with few, readily amenable, differences. The Japanese system used quite different data items.Conclusions:Data comparability suggests the feasibility of a global data management system that can store data from various countries. Such a system, if made accessible over the internet, would benefit resource-constrained countries by providing them with a ready-made framework to implement a surveillance system at low cost.