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Biomedical subjects

B Jeune

Publications and source records attributed to B Jeune.

At least 19 recordsLinked to original sources
PubMed2001

Recent advances in human gene-longevity association studies.

This paper reviews the recent literature on genes and longevity. The influence of genes on human life span has been confirmed in studies of life span correlation between related individuals based on family and twin data. Results from major twin studies indicate that approximately 25% of the variation in life span is genetically determined. Taking advantage of recent developments in molecular biology, researchers are now searching for candidate genes that might have an influence on life span. The data on unrelated individuals emerging from an ever-increasing number of centenarian studies makes this possible. This paper summarizes the rich literature dealing with the various aspects of the influence of genes on individual survival. Common phenomena affecting the development of disease and longevity are discussed. The major methodological difficulty one is confronted with when studying the epidemiology of longevity involves the complexity of the phenomenon, which arises from the polygenic nature of life span and historical mortality change. We discuss this issue and suggest new methodological approaches.

Humans↗
PubMed2001

Non-independence of individuals in a population of Drosophila melanogaster: effects on spatial distribution and dispersal.

We used a simple quadrat analysis to globally categorise the spatial distribution of Drosophila melanogaster individuals. Individuals were spatially aggregated and this was not only due to sexual attraction. This aggregation seemed to be maintained during dispersal, hence explaining the great variability of this behaviour observed in our work and by other authors. Thus, individuals are expected to arrive as small groups into a new patch. This may induce costs through competition and benefits by ensuring the presence of reproductive mates and/or if there is a phenomenon of local resource enhancement by the presence of conspecifics, hence influencing the evolution of dispersal.

Animals↗
PubMed2001

Outbreak of Hepatitis B among injecting drug users in Denmark.

BACKGROUND: The incidence of hepatitis B is low in Denmark, but injecting drug users (IDUs) remains a high-risk group for this infection. OBJECTIVES: The aim of the study was to describe a hepatitis B outbreak among IDUs by comparing existing registers. Additionally, we wanted to analyze the genetic variation of the hepatitis B virus involved in the outbreak. STUDY DESIGN: In the County of Funen, registers of laboratory diagnosis, hospital records and reports from clinicians to the Medical Officer of Health (MOH) were compared between 1992 and 1998. HBsAg positive sera recovered from the epidemic were sequenced and compared to known HBV strains. RESULTS: We identified 648 cases of hepatitis B of which 51% (332) were acute infections. The laboratory database identified 96% (319/332) of these, 45% (150/332) were admitted to hospital and 38% (127/332) were reported to public health. By capture-recapture analysis based on MOH reports and hospital records the estimated total number of acute cases were 334 (95% C.I. 283-385). We sequenced 75 HBsAg positive samples and identified two very similar strains of genotype D (serotype ayw3) among IDUs involved in the outbreak. CONCLUSIONS: The current surveillance system did not detect the majority of acute hepatitis B cases in County of Funen. We suggest laboratory-based surveillance of hepatitis B to be implemented at a national level as this may identify new outbreaks faster and more complete than the current surveillance system.

Denmark↗
PubMed2001

Functional status and self-rated health in 2,262 nonagenarians: the Danish 1905 Cohort Survey.

OBJECTIVES: To describe the functional capacity and self-rated health of a large cohort of nonagenarians. DESIGN: A cross-sectional survey of all Danes born in 1905 (92-93 years of age), carried out August to October 1998. SETTING: Participants' homes. PARTICIPANTS: Two thousand two hundred and sixty-two nonagenarians, corresponding to a participation rate of 63% (of these, 20% participated by proxy). MEASUREMENTS: Activities of daily living (ADLs) and self-rated health were assessed by interview. Five items from Katz's ADLs (bathing, dressing, transfer, toileting, and eating) were used to construct a three-level five-item ADL scale (not disabled (no disabilities), moderately disabled (1-2 disabilities), severely disabled (3-5 disabilities)). From responses to a more extensive list of questions on ADLs (26 items), we identified scales of strength and agility by means of factor analysis. Furthermore, a 26-item ADL scale was made. Physical performance tests (chair stand, timed walk, lifting a 2.7 kg box, maximum grip-strength, and flexibility tests) were performed among nonproxy responders. RESULTS: According to the five-item ADL scale, 50% of the men and 41% of the women were categorized as not disabled, while 19% and 22%, respectively, were categorized as severely disabled. The five-item ADL scale correlated highly with the 26-item ADL scale (r = 0.83). The ADL scales showed moderate-to-good correlation with each other (r = 0.74-0.83), and with the physical performance tests (r = 0.31-0.58). Only 3.7% of the women and 6.3% of the men walked (normal pace) with a speed of at least 1 meter per second, which is the minimum walking speed required to cross signaled intersections in Denmark. A total of 56% considered their health to be excellent or good. Of the participants, 74% were always or almost always satisfied with their lives, even though only 45% reported that they "felt well enough to do what they wanted." The analyses showed that no single ADL item seemed to be of particular importance for how the participants rated their health. CONCLUSION: The Danish 1905 cohort survey is the largest and the only nationwide survey of a whole birth-cohort of nonagenarians. A total of 2,262 fairly nonselected nonagenarians participated. The level of both self-reported disability and functional limitations measured by physical performance tests among nonagenarians was high. Despite their lower mortality, women were more disabled than men and did not perform as well as men in the physical performance tests. Nevertheless, the majority of the participants considered their health to be good and were satisfied with their lives.

Activities of Daily Living↗
PubMed2001

Dementia is not inevitable: a population-based study of Danish centenarians.

The authors evaluated the prevalence of dementia in centenarians. In this population-based survey, persons living in Denmark who turned 100 during the period April 1, 1995--May 31, 1996 (N = 276) were interviewed and examined at their residences. Additional health information was retrieved from medical files, including the National Discharge Registry. A participation rate was 75%, and no differences were found between participants and nonparticipants regarding sex and type of housing. The prevalence of mild to severe dementia in centenarians was 51%; 37% had no signs of dementia. Among the 105 demented centenarians, 13 (12%) had diseases (vitamin B12 and folic acid deficiencies, hypothyroidism, Parkinson's disease) that could contribute to a dementia diagnosis. Of the remaining 92 demented participants, 46 (50%) had 1 one or more cerebro- or cardiovascular diseases known to be risk factors in the development of dementia. The prevalence of these risk factors was the same in demented and nondemented participants, whereas hypertension was significantly more frequent in nondemented than demented participants. Dementia is common but not inevitable in centenarians. Cerebro- and cardiovascular diseases are equally common in demented and nondemented persons.

Age Distribution↗
PubMed2000

X-linked genetic factors regulate hematopoietic stem-cell kinetics in females.

X inactivation makes females mosaics for 2 cell populations, usually with an approximate 1:1 distribution. Skewing of this distribution in peripheral blood cells is more common among elderly women. The depletion of hematopoietic stem cells followed by random differentiation may explain the acquired skewing with age. However, an animal model suggests that selection processes based on X-linked genetic factors are involved. We studied peripheral blood cells from 71 monozygotic twin pairs aged 73 to 93 years and from 33 centenarians, and we found that with age, 1 of the cell populations becomes predominant for most women. We also observed a strong tendency for the same cell line to become predominant in 2 co-twins. This suggests that X-linked genetic factors influence human hematopoietic stem cell kinetics. The fact that females have 2 cell lines with different potentials could be one of the reasons women live longer than men.

Aged↗
PubMed2000

Estimation of apolipoprotein E genotype-specific relative mortality risks from the distribution of genotypes in centenarians and middle-aged men: apolipoprotein E gene is a "frailty gene," not a "longevity gene".

We developed a method to estimate genotype-specific average relative mortality risk, R, from genotype distributions in cross-sectional studies of people belonging to different age-groups, and applied the method to new data from a study of apolipoprotein E genotypes (apoE) in 177 Danish centenarians and data from a study of 40-year-old Danish men. Twenty-one percent of the centenarians were epsilon 2-carriers (genotypes epsilon 2 epsilon 2 and epsilon 3 epsilon 2) and 15% were epsilon 4-carriers (genotypes epsilon 4 epsilon 4 and epsilon 4 epsilon 3) compared to 13 and 29%, respectively, of the young men. The R-values were 0.95 (95% CI 0.88 to 1.02) for epsilon 2-carriers and 1.13 (95% CI 1.05 to 1.22) for epsilon 4-carriers, using epsilon 3 epsilon 3- and epsilon 4 epsilon 2 genotypes as reference. Corresponding values for epsilon 4-carriers were obtained by using published data from a French and a Finnish study of centenarians, whereas the values for epsilon 2-carriers were about 0.90 with these data. The method to estimate mortality risk and the results associate with the view that the apoE gene is a "frailty gene." On the other hand, if odds ratios are used to summarize data from studies of this kind, they are more impressive and may propagate the misconception that apoE is a "longevity gene".

Adult↗
PubMed2000

Virulence variability of the Drosophila C virus and effects of the microparasite on demographic parameters of the host (Drosophila melanogaster).

We carried out experiments with the Drosophila C virus (DCV), a nonhereditary virus acting on demographic parameters of infected Drosophila host populations. It is well known that DCV increases mortality rate, decreases developmental time, and increases daily fecundity. As usual for Drosophila viruses, the DCV was multiplied in vivo. In this study we tested the hypothesis of virulence variability in DCV strains by isolating different stocks of the virus. The flies were tested for susceptibility to injection of such isolates and for virulence variability. Possible interactions between demographic parameters in three Drosophila host populations and injected isolates were studied under two egg densities (low and high). The hypothesis of virulence variability of DCV was supported by significant differences in mortality rates, depending on whether virus isolates were ingested or injected. When DCV was ingested, differences between host mortality rates were independent of the Drosophila host populations. Nevertheless, the developmental time was equally decreased by each virus isolate, independent of the host population. Moreover, the two viral stocks strongly increased the egg production of the flies. This experimental approach clearly showed that DCV could be considered a polymorphic virus. The phenotypic interactions between DCV and host flies varied according to parasite genotype.

Animals↗
PubMed2000

Maximal oxygen uptake, muscle strength and walking speed in 85-year-old women: effects of increased physical activity.

This study explores the effect of regular training on blood pressure, maximal oxygen uptake, maximal isometric muscle strength, and walking speed in the very old. A total of 55 community-dwelling women, 85-year-old, were enrolled in a training group (N = 22) or a control group (N = 33). These groups were reduced to 19 and 26 subjects, respectively, after the training period. Training was performed once a week over eight months, and consisted of various exercises with particular attention to movements important for everyday activities. Training reduced diastolic blood pressure (p < 0.05), and showed a similar trend for systolic blood pressure. Measurements of maximal oxygen uptake before the start of the training (15 mL min-1 kg-1) revealed a level close to the presumed limit for independent living (13 mL min-1 kg-1). Training improved VO2 max by 18% (p < 0.05), whereas the control group experienced a trend towards a reduction. Maximal isometric muscle strength of both the right and left leg showed a tendency to increase with training, but no significant changes were evident in the trunk flexor and extensor muscles. The training group showed a significant increase of 17% in maximal walking speed after the training period. However, one year later, without training, this improvement was reduced to 8% (p < 0.05). No major changes were observed in the control group for any of these parameters. This study demonstrates a maximal oxygen capacity in very old community-dwelling women close to a threshold level indicating dependency. Furthermore, 8 months of regular training appears to lower blood pressure, and to increase maximal oxygen uptake and maximal walking speed. This suggests that physical reactivation of the very old may reduce the risk for acquiring age-related diseases associated with an elevated blood pressure, and may improve parameters crucial for independence.

Aged↗
PubMed2000

Lentil root statoliths reach a stable state in microgravity.

The kinetics of the movement of statoliths in gravity-perceiving root cap cells of Lens culinaris L. and the force responsible for it have been analysed under 1 g and under microgravity conditions (S/MM-03 mission of Spacehab 1996). At the beginning of the experiment in space, the amyloplasts were grouped at the distal pole of the statocytes by a root-tip-directed 1-g centrifugal acceleration. The seedlings were then placed in microgravity for increasing periods of time (13, 29, 46 or 122 min) and chemically fixed. During the first 29 min of microgravity there were local displacements (mean velocity: 0.154 microm min(-1)) of some amyloplasts (first at the front of the group and then at the rear). Nevertheless, the group of amyloplasts tended to reconstitute. After 122 min in microgravity the bulk of amyloplasts had almost reached the proximal pole where further movement was blocked by the nucleus. After a longer period in microgravity (4 h; experiment carried out 1994 during the IML 2 mission) the statoliths reached a stable position due to the fact that they were stopped by the nucleus. The position was similar to that observed in roots grown continuously in microgravity. Treatment with cytochalasin D (CD) did not stop the movement of the amyloplasts but slowed down the velocity of their displacement (0.019 microm min(-1)). Initial movement patterns were the same as in control roots in water. Comparisons of mean velocities of amyloplast movements in roots in space and in inverted roots on earth showed that the force responsible for the movement in microgravity (Fc) was about 86% less (Fc = 0.016 pN) than the gravity force (Fg = 0.11 pN). Treatment with CD reduced Fc by two-thirds. The apparent viscosity of the statocyte cytoplasm was found to be 1 Pa s or 3.3 Pa s for control roots or CD treated roots, respectively. Brownian motion or elastic forces due to endoplasmic reticulum membranes do not cause the movement of the amyloplasts in microgravity. It is concluded that the force transporting the statoliths is caused by the actomyosin system.

Fabaceae↗
PubMed2000

Prevention of secondary cases of meningococcal disease in Denmark.

Close contacts of cases of meningococcal disease are at increased risk of disease themselves. We identified household-like contacts of index cases, to investigate whether relevant target groups are informed, receive and follow recommended chemoprophylaxis and vaccination, and to ascertain the time delay for implementation of these measures. A telephone interview of 172 households of index cases and a questionnaire survey among 634 parents of contacts of cases in institutions were carried out. Results were compared with reports from Medical Officers of Health. In 21% of the cases, Medical Officers reported fewer household-like contacts than were identified in this study. Written information was effective. However, 59% of households, and 36% of parents of contacts in institutions felt a lack of information about how the disease is acquired, the risk and signs of illness. For household-like contacts the coverage rate for chemoprophylaxis with an appropriate drug was 90% and for vaccination 59%. No secondary cases occurred among those treated with chemoprophylaxis, but among those not treated, there were two secondary cases. The study design provided a useful audit methodology to evaluate the completeness of implementation and the success of prophylactic measures for meningococcal disease.

Adolescent↗
PubMed2000

A two-fold difference in the age-adjusted prevalences of Parkinson's disease between the island of Als and the Faroe Islands.

With the aim of comparing the previously found high prevalence of idiopathic Parkinson's disease (PD) in the Faroe Islands with the prevalence of PD in an area of Denmark, we used the same case-finding methods for case ascertainment and the same strict criteria to diagnose PD on the island of Als. During the last year before the prevalence date (1 January 1998), we found in various registries from pharmacies, hospital, private neurologist and general practitioners 121 patients with suspected Parkinsonism out of 56,839 inhabitants on the island of Als. After exclusion of those who had other diseases, a total of 79 patients were left for further examinations. Among these we found 58 with PD. The overall prevalence of PD was estimated to be 102.0 and the age-adjusted prevalence to be 98.3 per 100,000 persons compared with 187.6 and 209.0 in the Faroe Islands. Compared with the previous results from the Faroe Islands (prevalence date 1 July 1995) we found an even lower mean age at onset of PD symptoms and at onset of treatment, a lower proportion of definite PD and a lower average dose of levodopa. We therefore conclude that the two-fold higher prevalence in the Faroe Islands than on the island of Als was not due to an early diagnosis and a higher ascertainment of cases with mild PD, which was suggested as being one possible explanation for our previous finding of a high prevalence of PD in the Faroe Islands.

Age Distribution↗
PubMed2000

An epidemic of parvovirus B19 in a population of 3,596 pregnant women: a study of sociodemographic and medical risk factors.

OBJECTIVES: To estimate the incidence of human parvovirus B19 among pregnant women before and during an epidemic, to elucidate possible sociodemographic and medical risk factors during pregnancy and to estimate the association between parvovirus B19 infection and negative pregnancy outcome. DESIGN: Prospective study among pregnant women followed from their first antenatal visit before 24 full weeks of gestation until delivery. SETTING: Department of Obstetrics and Gynaecology, Odense University Hospital, Denmark, November 1992 to February 1994. METHODS: 3,596 pregnant women were invited to participate. The women were examined at first antenatal visit in the period from November 1992 to February 1994 and at delivery. The last delivery was in August 1994 and samples were thus collected before and during a large parvovirus B19 epidemic in Denmark January to September 1994. A blood sample for parvovirus B19 serology was taken at enrollment and from the umbilical cord at delivery. Three questionnaires were completed during 2nd and 3rd trimesters and a registration form at delivery. In total, 3,174 (87.6%) were enrolled and 79.5% completed the study. RESULTS: The prevalence of B19 IgG seropositivity at the first antenatal visit before 24 full weeks of gestation was 66% . The cumulative prevalence proportion of acute parvovirus B19 infection during pregnancy among IgG negative women was found to be 10.3% (IgM seropositivity and/or IgG seroconversion). The IgG seroconversion incidence increased significantly from 1.0% to 13.5% among 932 seronegative pregnant women before and during the epidemic, respectively (P < 0.001). Independent risk factors related to increased risk of B19 infection during pregnancy, adjusted for other sociodemographic and medical factors, were: children at home (adjusted OR 2.1, 95% CI 1.3-3.2); serious medical disease (adjusted OR 3.0, 95% CI 1.0-8.5); and a stressful job (adjusted OR 1.8, 95% CI 1.0-3.3). Parvovirus B 19 IgM seropositivity was associated with events of late spontaneous abortions and stillbirths (crude OR 9.9; 95% CI 3.3-29.4). CONCLUSION: Before and during an epidemic of acute B19 infection incidences were measured among pregnant women to be 1.0% and 13.5%, respectively. Three factors, significantly increasing the risk of acute B19, were identified as: having children at home; suffering from serious medical diseases; and having a stressful job. IgM positivity for parvovirus B19 was associated with negative outcome of pregnancy.

Abortion, Spontaneous↗
PubMed1999

Optimized lymphocyte protein extraction performed simultaneously with DNA and RNA isolation: application to the study of factors affecting DNA, RNA, and protein recovery from lymphocytes of the oldest individuals.

We describe an optimized procedure for protein extraction performed simultaneously with that of DNA and RNA from a single tissue sample that is, unlike the original protocol, suitable for quantitative studies. This optimized protocol is particularly well adapted to studies where gene regulation at DNA, RNA, and protein levels must be examined simultaneously, and when the amount of starting biological material is limited. We applied this procedure to the study of factors affecting both qualitatively and quantitatively the extraction of DNA, RNA, and proteins from lymphocytes of very old individuals, since we observed variability in the recovery of these molecular species with advanced age. Therefore, we investigated the combined effects of age and time delay between blood collection and lymphocyte isolation on the recovery of DNA, RNA, and proteins simultaneously extracted from Danish nonagenarians and centenarians versus younger adult samples. Our results suggest that neither RNA nor DNA nor protein contents of lymphocytes are altered with aging. However, the quantity of RNA and protein recovery is affected by a 24-h delay in blood processing. This effect is more pronounced in the oldest, particularly for RNA, and may affect data interpretation of age-dependent gene expression studies.

3T3 Cells↗
PubMed1999

[Occupational hand injuries. A population-based description of the incidence and referral to casualty departments].

The overall incidence of self-reported occupational hand injuries in a Danish population was estimated to 4.7%, with the highest incidence among the youngest, men and employees in the production and building industries. The life-time risk were 93% for men and 73% for women. Age and gender were found to be independent risk factors for the occupational hand injuries. The proportion treated in the casualty department was 0.28, for injuries with disability and time off work the proportions were 0.46 and 0.69 respectively. No age, gender or occupation specific selection for attending the hospital was found. Prevention-trials against hand injuries should therefore have a high priority, and it is recommended that hospital data files are used increasingly in future prevention programs.

Accidents, Occupational↗