bluuebunny/crossref_metadata_2025_split huggingface dataset:
Previously Infected and Recovered Chimpanzees Exhibit Rapid Responses That Control Hepatitis C Virus Replication upon Rechallenge
Authors: Major Marian E. , Mihalik Kathleen , Puig Montserrat , Rehermann Barbara , Nascimbeni Michelina , Rice Charles M. , Feinstone Stephen M. 
Published: July 2002

ABSTRACT

Responses in three chimpanzees were compared following challenge with a clonal hepatitis C virus (HCV) contained in plasma from an animal that had received infectious RNA transcripts. Two of the chimpanzees (Ch1552 and ChX0186) had recovered from a previous infection with HCV, while the third (Ch1605) was a naïve animal. All animals were challenged by reverse titration with decreasing dilutions of plasma and became serum RNA positive following challenge. Ch1605 displayed a typical disease profile for a chimpanzee. We observed increasing levels of serum RNA from week 1 postinoculation (p.i.), reaching a peak of 10
6
copies/ml at week 9 p.i., and alanine aminotransferase (ALT) elevations and seroconversion to HCV antibodies at week 10 p.i. In contrast, both Ch1552 and ChX0186 exhibited much shorter periods of viremia (4 weeks), low serum RNA levels (peak, 10
3
copies/ml), and minimal ALT elevations. A comparison of intrahepatic cytokine levels in Ch1552 and Ch1605 showed greater and earlier gamma interferon (IFN-γ) and tumor necrosis factor alpha responses in the previously infected animal, responses that were 30-fold greater than baseline responses at week 4 p.i. for IFN-γ in Ch1552 compared to 12-fold in Ch1605 at week 10 p.i. These data indicate (i) that clonal HCV generated from an infectious RNA transcript will lead to a typical HCV infection in naïve chimpanzees, (ii) that there are memory immune responses in recovered chimpanzees that control HCV infection upon rechallenge, and (iii) that these responses seem to be T-cell mediated, as none of the animals had detectable antibody against the HCV envelope glycoproteins. These observations have encouraging implications for the development of a vaccine for HCV.
Antibody-Mediated Enhancement of Human Immunodeficiency Virus Type 1 Infectivity Is Determined by the Structure of gp120 and Depends on Modulation of the gp120-CCR5 Interaction
Authors: Guillon Christophe , Schutten Martin , Boers Patrick H. M. , Gruters Rob A. , Osterhaus Albert D. M. E. 
Published: July 2002

ABSTRACTIn this study, we characterized the viral determinants of coreceptor usage in relation to susceptibility to antibody-mediated neutralization or enhancement of infectivity by using chimeras of three highly related human immunodeficiency virus type 1 (HIV-1) isolates of different phenotypes. We found that the V3 region was the main determinant of antibody-mediated enhancement and coreceptor specificity but that the overall structure of gp120 was also important for these properties. Constructs susceptible to antibody-mediated enhancement preferentially use CCR5 as a coreceptor, in contrast to constructs that were neutralized or not affected. Using monoclonal antibodies directed against CD4 or CCR5, we were able to show that antibody-mediated enhancement was CD4 dependent. Altogether, our results suggest that the modulation of the interaction of gp120 with CCR5 is the mechanism underlying antibody-mediated enhancement of HIV-1 infectivity.
Both Viral Transcription and Replication Are Reduced when the Rabies Virus Nucleoprotein Is Not Phosphorylated
Authors: Wu Xianfu , Gong Xiaoming , Foley Heather D. , Schnell Matthias J. , Fu Zhen F. 
Published: July 2002

ABSTRACT
Rabies virus nucleoprotein (N) plays vital roles in regulation of viral RNA transcription and replication by encapsidation of the nascent genomic RNA. Rabies virus N is phosphorylated, and previous studies demonstrated that mutation of the phosphorylated serine at position 389 to alanine resulted in reduction of viral transcription and/or replication of a rabies virus minigenome. In the present study, we mutated the serine (S) at position 389 to alanine (A), glycine (G), aspartic acid (D), asparagine (N), glutamic acid (E), and glutamine (Q) and examined the effects of these mutations on rabies virus transcription and replication in the minigenome. Furthermore, mutations from S to A, S to D, and S to E were also incorporated into the full-length infectious virus. Mutation of the serine to each of the other amino acids resulted in the synthesis of an unphosphorylated N and reduction of viral transcription and replication in the minigenome. Mutations from S to A and S to D also resulted in reduction of both viral transcription and replication in full-length infectious viruses. Growth curve studies indicated that production of the mutant virus with the S-to-A mutation (L16A) was as much as 10,000-fold less than that of the wild-type virus (L16). Northern blot hybridization with rabies virus gene probes revealed that the rates of viral transcription and replication were reduced by as much as 10-fold in the mutant viruses when the N was not phosphorylated. Interpretation of the data from the minigenome system and the full-length infectious virus indicates that phosphorylation of rabies virus N is necessary for replication. Further studies involving cycloheximide treatment of infected cells revealed that viral transcription was also reduced when the N was not phosphorylated. Taken together, these results provide definitive evidence that N phosphorylation plays an important role in the processes of rabies virus transcription and replication.
Does physical activity reduce the risk of developing peptic ulcers?
Authors: Cheng Yiling , Macera Caroline A , Davis Dorothy R , Blair Steven N 
Published: July 2002

Background—AlthoughHelicobacter pylorihas been identified as a major cause of chronic gastritis, not all infected patients develop ulcers, suggesting that other factors such as lifestyle may be critical to the development of ulcer disease.Aim—To investigate the role physical activity may play in the incidence of peptic ulcer disease.Methods—The subjects were men (8529) and women (2884) who attended the Cooper Clinic in Dallas between 1970 and 1990. The presence of gastric or duodenal ulcer disease diagnosed by a doctor was determined from a mail survey in 1990. Subjects were classified into three physical activity groups according to information provided at the baseline clinic visit (before 1990): active, those who walked or ran 10 miles or more a week; moderately active, those who walked or ran less than 10 miles a week or did another regular activity; the referent group consisting of those who reported no regular physical activity.Results—With the use of gender specific proportional hazards regression models that could be adjusted for age, smoking, alcohol use, body mass index, and self reported tension, active men were found to have a significant reduction in risk for duodenal ulcers (relative hazard (95% confidence interval) for the active group was 0.38 (0.15 to 0.94) and 0.54 (0.30 to 0.96) for the moderately active group). No association was found between physical activity and gastric ulcers for men or for either type of ulcer for women.Conclusions—Physical activity may provide a non-pharmacological method of reducing the incidence of duodenal ulcers among men.
Effectiveness of headgear in a pilot study of under 15 rugby union football
Authors: McIntosh A S , McCrory P 
Published: July 2002

Objective—To determine whether protective headgear reduced the incidence of concussion in a pilot study of under 15 rugby union.Methods—Sixteen under 15 rugby union teams were recruited from three interschool competitions in metropolitan Sydney and the adjacent country region. A prospective study was undertaken over a single competitive season. The study had two arms: a headgear arm and a control arm. Headgear wearing rates and injury data were reported to the investigators and verified using spot checks.Results—A total of 294 players participated in the study. There were 1179 player exposures with headgear and 357 without headgear. In the study time frame, there were nine incidences of concussion; seven of the players involved wore headgear and two did not. There was no significant difference between concussion rates between the two study arms.Conclusions—Although there is some controversy about the desirability of wearing protective headgear in football, this pilot study strongly suggests that current headgear does not provide significant protection against concussion in rugby union at a junior level.
A reduction in training volume and intensity for 21 days does not impair performance in cyclists
Authors: Rietjens G J W M , Keizer H A , Kuipers H , Saris W H M 
Published: July 2002

Objectives—(a) To investigate the effects of reduced training on physical condition and performance in well trained cyclists; (b) to study whether an intermittent exercise programme would maintain physiological training adaptations more effectively than a continuous exercise programme during a period of reduced training.Methods—Twelve male cyclists participated in a 21 day training programme and were divided into two training groups. One group (age 25.3 (7) years; weight 73.3 (5.7) kg; Vo2max58.6 (4.5) ml/kg/min; means (SD)) underwent a continuous endurance exercise training programme (CT) whereas the second group (age 22.8 (3.5) years; weight 74.1 (7.0) kg; Vo2max59.7 (6.7) ml/kg/min) followed an intermittent endurance exercise training programme (IT). During this reduced training period, both groups trained for two hours a day, three days a week.Results—Neither group showed changes in maximal workload (Wmax) (4.6 (0.5)v4.8 (0.5) W/kg and 4.6 (0.5)v4.7 (0.6) W/kg for the CT and IT group respectively) and Vo2max(58.6 (4.5)v60.1 (5.8) ml/kg/min and 59.7 (6.7)v58.8 (7.5) ml/kg/min for the CT and IT group respectively). During the submaximal steady state exercise test, substrate use and heart rate remained unchanged after reduced training.Conclusions—These results indicate that well trained cyclists who reduce training intensity and volume for 21 days can maintain physiological adaptations, as measured during submaximal and maximal exercise. An intermittent training regimen has no advantage over a continuous training regimen during a detraining period.
Randomised controlled trial of prophylactic etamsylate: follow up at 2 years of age
Authors: Elbourne D , Ayers S , Dellagrammaticas H , Johnson A , Leloup M , Lenoir-Piat S 
Published: July 2002

AIMTo assess the role of etamsylate* in reducing the risk of haemorrhagic brain damage and its consequences.DESIGNFollow up of babies recruited into a randomised controlled trial.METHODSA total of 334 infants born before 33 weeks gestation in France and Greece were randomly allocated within the first four hours of birth either to receive etamsylate or to act as controls. The principal outcomes in the trial were death or impairment and/or disability at the age of 2 years.RESULTSFifty nine children were lost to follow up. A total of 115 (34%) either died or had some impairment or disability, and 88 (26%) either died or had severe impairment or disability at 2 years of age. These outcomes did not differ significantly between the two randomised groups: relative risks and 95% confidence intervals 1.14 (0.78 to 1.4) and 1.17 (0.82 to 1.68) respectively. The findings were similar for all the prespecified subgroup analyses stratified by key prognostic factors at trial entry: country of birth, gestational age < or ⩾ 29 weeks, inborn or outborn, age < or ⩾  1 hour, and with or without cerebral scan abnormality.CONCLUSIONThese findings do not support the use of etamsylate. Other strategies need to be evaluated for the prevention of mortality and morbidity in these vulnerable infants.Key messagesThe findings from the only published follow up of children from a randomised controlled trial of etamsylate do not support its use when given within the first four hours of birth to infants born before 33 weeks gestationCentres in Greece and France recruited 334 infants into the trial, and did not find that etamsylate reduced the risk of haemorrhagic brain damage or its consequences in terms of death or impairment and/or disabilityOther strategies need to be evaluated for the prevention of mortality and morbidity in these vulnerable infants
BRCA1 andBRCA2 mutation status and cancer family history of Danish women affected with multifocal or bilateral breast cancer at a young age
Authors: Bergthorsson J T , Ejlertsen B , Olsen J H , Borg A , Nielsen K V , Barkardottir R B , Klausen S , Mouridsen H T , Winther K , Fenger K , Niebuhr A , Harboe T L , Niebuhr E 
Published: July 2002

INTRODUCTIONA small fraction of breast cancer is the result of germline mutations in theBRCA1 and BRCA2cancer susceptibility genes. Mutation carriers frequently have a positive family history of breast and ovarian cancer, are often diagnosed at a young age, and may have a higher incidence of double or multiple primary breast tumours than breast cancer patients in general.OBJECTIVESTo estimate the prevalence and spectrum of BRCA1 andBRCA2 mutations in young Danish patients affected with bilateral or multifocal breast cancer and to determine the relationship of mutation status to family history of cancer.SUBJECTSFrom the files of the Danish Breast Cancer Cooperative Group (DBCG), we selected 119 breast cancer patients diagnosed before the age of 46 years with either bilateral (n=59) or multifocal (n=61) disease.METHODSDNA from the subjects was screened for BRCA1 andBRCA2 mutations using single strand conformation analysis (SSCA) and the protein truncation test (PTT). Observed and expected cancer incidence in first degree relatives of the patients was estimated using data from the Danish Cancer Registry.RESULTSTwenty four mutation carriers were identified (20%), of whom 13 had aBRCA1 mutation and 11 carried aBRCA2 mutation. Two mutations inBRCA1 were found repeatedly in the material and accounted for seven of the 24 (29%) mutation carriers. The mutation frequency was about equal in patients with bilateral (22%) and multifocal breast cancer (18%). The incidence of breast and ovarian cancer was greatly increased in first degree relatives ofBRCA1 and BRCA2mutation carriers, but to a much lesser degree in relatives of non-carriers. An increased risk of cancer was also noted in brothers of non-carriers.CONCLUSIONSA relatively broad spectrum of germline mutations was observed inBRCA1 and BRCA2and most of the mutations are present in other populations. Our results indicate that a diagnosis of bilateral and multifocal breast cancer is predictive of BRCA1 andBRCA2 mutation status, particularly when combined with information on the patients' age at diagnosis and family history of breast/ovarian cancer.
Exposure to silica and silicosis among tin miners in China: exposure-response analyses and risk assessment
Authors: Chen W , Zhuang Z , Attfield M D , Chen B T , Gao Pi , Harrison J C , Fu C , Chen J-Q , Wallace W E 
Published: July 2002

OBJECTIVESTo investigate the risk of silicosis among tin miners and to investigate the relation between silicosis and cumulative exposure to dust (Chinese total dust and respirable crystalline silica dust).METHODSA cohort study of 3010 miners exposed to silica dust and employed for at least 1 year during 1960–5 in any of four Chinese tin mines was conducted. Historical total dust data from China were used to create a job exposure matrix for facility, job title, and calendar year. The total dust exposure data from China were converted to estimates of exposure to respirable crystalline silica for comparison with findings from other epidemiological studies of silicosis. Each worker's work history was abstracted from the complete employment records in mine files. Diagnoses of silicosis were based on 1986 Chinese pneumoconiosis Roentgen diagnostic criteria, which classified silicosis as stages I-III—similar to an International Labour Organisation (ILO) classification of 1/1 or greater.RESULTSThere were 1015 (33.7%) miners identified with silicosis, who had a mean age of 48.3 years, with a mean of 21.3 years after first exposure (equivalent to 11.0 net years in a dusty job). Among those who had silicosis, 684 miners (67.4%) developed silicosis after exposure ended (a mean of 3.7 years after). The risk of silicosis was strongly related to cumulative exposure to silica dust and was well fitted by the Weibull distribution, with the risk of silicosis less than 0.1% when the Chinese measure of cumulative exposure to total dust (CTD) was under 10 mg/m3-years (or 0.36 mg/m3-years of respirable crystalline silica), increasing to 68.7% when CTD exposure was 150 mg/m3-years (or 5.4 mg/m3-years of respirable crystalline silica). Latency period was not correlated to the risk of silicosis or cumulative dose of exposure. This study predicts about a 36% cumulative risk of silicosis for a 45 year lifetime exposure to these tin mine dusts at the CTD exposure standard of 2 mg/m3, and a 55% risk at 45 years exposure to the current United States Occupational Safety and Health Administration and Mine Safety and Health Administration standards of 0.1 mg/m3100% respirable crystalline silica dust.CONCLUSIONSA clear exposure-response relation was detected for silicosis in Chinese tin miners. The study results were similar to most, but not all, findings from other large scale exposure-response studies.
Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey
Authors: Dumortier P , Çoplü L , Broucke I , Emri S , Selcuk T , de Maertelaer V , De Vuyst P , Baris I 
Published: July 2002

OBJECTIVESThe high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos.METHODSFerruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy.RESULTSFBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 μm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite.CONCLUSIONAnalysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.
Sickness absence in diabetic employees
Authors: Škerjanc A 
Published: July 2002

OBJECTIVESTo compare sickness absence among diabetic and non-diabetic employees.METHODSA cross sectional case-control study was conducted in a random sample of 400 diabetic employees 21–50 years old from Ljubljana that compared their sickness absence in the year 1996 with sickness absence of non-diabetic employees matched by sex, age, and occupation. Sickness absence was compared in total and also in subgroups formed by sex, age, occupation, and disability. Non-parametric statistics were used (χ2test, Wilcoxon matched pairs test).RESULTSThe randomised sample consisted of 61.2% of men (245) and 38.8% of women (155) with a mean age of 42.5 years. Unskilled workers made up 30.2% of employees, and less than 16.4% were highly educated. Among diabetic employees there were 7.0% disabled and among non-diabetic employees 2.0%. The mean frequency of sickness absences of diabetic employees was 0.89 times in the year 1996 (95% confidence interval (95% CI) 0.70 to 1.08), and of non-diabetic employees 0.56 times (95% CI 0.47 to 0.65), p=0.01. The mean total duration of sickness absence of diabetic employees was 31.71 days (95% CI 24.86 to 38.57), of non-diabetic employees 16.57 days (95% CI 11.72 to 21.42), p<0.01. Differences were also found in subgroups but the size of subgroups was not sufficient to detect significant differences.CONCLUSIONSThe study confirmed that diabetes affects the ability to work. Appropriate work and good control of the disease are important to prevent long term complications.
The EMECAM project: a multicentre study on air pollution and mortality in Spain: combined results for particulates and for sulfur dioxide
Authors: Ballester F , Sáez M , Pérez-Hoyos S , Iñíguez C , Gandarillas A , Tobías A , Bellido J , Taracido M , Arribas F , Daponte A , Alonso E , Cañada A , Guillén-Grima F , Cirera L , Pérez-Boíllos M J , Saurina C , Gómez F , Tenías J M 
Published: July 2002

Objective: The EMECAM study is a collaborative effort to evaluate the impact of air pollution on mortality in Spain. In this paper the combined results are presented for the short term effects of particulates and sulfur dioxide on both daily mortality for all and for specific causes.Methods: The relation between daily mortality for all causes, cardiovascular diseases, and respiratory diseases, and air pollution for particulates (daily concentrations) and SO2(24 and 1 hour concentrations) was assessed in 13 Spanish cities for the period 1990–6. With a standardised method, magnitude of association in each city was estimated by Poisson regression in a generalised additive model. Local estimates were obtained from both single and two pollutant analyses. Lastly, combined estimates for each cause and pollutant were obtained.Results: For combined results, in single pollutant models a 10 μg/m3increase in the concentration of the mean of the concurrent and one day lag for black smoke was associated with a 0.8% (95% confidence interval (95% CI) 0.4 to 1.1%) increase in total mortality. The estimates for total suspended particles (TSPs) and particulate matter of aerodynamic diameter <10 μm (PM10) and total mortality were slightly lower. The same increase in concentrations of SO2was associated with a 0.5% increase in daily deaths. For groups of specific causes, higher estimations were found, specially for respiratory conditions. Peak concentrations of SO2showed significant associations with the three groups of mortality. When two pollutant analyses were performed, estimates for particulates, specially for black smoke, did not substantially change. The estimates for daily concentrations of SO2were greatly reduced, but, on the contrary, the association with peak concentrations of SO2did not show any change.Conclusions: There is an association between mortality and pollution through particulates among city populations in Spain. Peak rather than daily concentrations of SO2were related to mortality. Results suggest that populations in Spanish cities are exposed to health risks derived from air pollution.