Biomedical subjects

Bernard Jeune

Publications and source records attributed to Bernard Jeune.

35 records · Page 2Linked to original sources

PubMed2004

[Descartes and medicine].

The French philosopher and mathematician René Descartes (1596-1650) gave a high priority to medicine and dedicated a great deal of his life to medical studies. Nevertheless his relation to medicine has always been much discussed. However, a number of recent works have contributed to reassessing the earlier critique which nearly wrote him out from medical history. The recent biographical dismissal of a number of earlier allegations and the recent interpretations of the medical contents of his collected writings ought to result in Descartes' reinstatement in medical history. His novel anti-Aristotelian methodology had a crucial influence on the medicine of the subsequent decades. Also his early defense of Harvey's theory of blood circulation had great influence. Especially his thoughts about a mechanical physiology by means of which the functions of the body could be explained without involvement of "occult faculties" influenced that time. His empirical mistakes, including the central role which he ascribed to the corpus pineale, are offset, which already Steno noted, by his brilliant thoughts about the function and importance of the brain. Although he did not make any really new empirical discoveries within medicine, he advanced a number of concrete ideas which later lead to actual discoveries such as visual accommodation, the reflex concept and the reciprocal innervations of antagonistic muscles. Descartes' psychosomatic view of the importance of the interplay between sensations, "the passions of the soul", and the free will in the preservation of health shows in addition that his fundamental soul-body dualism was far more nuanced than is often claimed.

Historiography↗

PubMed2003

Elevated levels of tumor necrosis factor alpha and mortality in centenarians.

BACKGROUND: Aging is accompanied by low-grade inflammation. Tumor necrosis factor (TNF) alpha initiates the cytokine cascade, and high levels are associated with dementia and atherosclerosis in persons aged 100 years. We hypothesized that TNF-alpha was also a prognostic marker for all-cause mortality in these persons. METHODS: We enrolled 126 subjects at or around the time of their 100th birthday. Plasma levels of TNF-alpha, interleukin (IL)-6, IL-8, and C-reactive protein were measured at baseline, and we determined the associations between the markers of inflammation and mortality during the subsequent 5 years. RESULTS: Only 9 subjects were alive after 5 years. Elevated levels of TNF-alpha were associated with mortality in both men and women (hazard ratio = 1.34 per SD of 2.81 pg/mL; 95% confidence interval: 1.12 to 1.60, P = 0.001). Levels of IL-6 and IL-8 did not affect survival; levels of C-reactive protein were not associated with mortality when levels of TNF-alpha were included in the analysis. Dementia and cardiovascular diseases represented the major causes of comorbid conditions at baseline. TNF-alpha was still associated with mortality in multivariate models that included these parameters as confounders. CONCLUSION: TNF-alpha was an independent prognostic marker for mortality in persons aged 100 years, suggesting that it has specific biological effects and is a marker of frailty in the very elderly.

Aged↗

PubMed2003

Predictors of mortality in 2,249 nonagenarians--the Danish 1905-Cohort Survey.

OBJECTIVES: : To elucidate whether well-known predictions of mortality are reduced or even reversed, or whether mortality is a stochastic process in the oldest old. DESIGN: : A multidimensional survey of the Danish 1905 cohort conducted in 1998 with follow-up of vital status after 15 months. SETTING: : Denmark. PARTICIPANTS: : All Danes born in 1905, irrespective of physical and mental status were approached. Two thousand two hundred sixty-two persons of 3,600 participated in this survey. MEASUREMENTS: : Professional interviewers collected data concerning sociodemographic factors, smoking, alcohol consumption, body mass index, physical and cognitive performance, and health during a visit at the participant's residency. Cox regression models were used to evaluate predictors of mortality. RESULTS: : Five hundred seventy-nine (25.7%) of the 2,249 participants eligible for the analysis died during the 15 months follow-up. Multivariate analyses showed that marital status, education, smoking, obesity, consumption of alcohol, and number of self-reported diseases were not associated with mortality. Disability and cognitive impairment were significant risk factors in men and women. In addition poor self-rated health was associated with an increase in mortality in women. CONCLUSION: : In the oldest old, several known predictors of mortality, such as sociodemographic factors, smoking, and obesity, have lost their importance, but a high disability level, poor physical and cognitive performance, and self-rated health (women only), predict mortality, which shows that mortality in the oldest old is not a stochastic process.

Activities of Daily Living↗

PubMed2003

Differences in suicide between the old and the oldest old.

OBJECTIVES: The purpose of our study is to examine suicide trends among the old (65-79 years) and oldest old (80+ years). METHODS: All persons aged 50 or older who committed suicide in Denmark during 1972-1998 are included in the analysis. Suicide trends are analyzed by sex, age, civil status, and methods. Age, period, and cohort effects are examined graphically. RESULTS: In all, 17,729 persons (10,479 men and 7,250 women) committed suicide. During the study period, the suicide trends among the middle-aged and the old adults decreased. The trend among the oldest old, by contrast, remained stable. Marriage ceases to have a preventive effect among the oldest old. The oldest old tend to use more determined suicide methods. DISCUSSION: Distinct differences in suicide mortality between the old and the oldest old were found. The suicide trend of the oldest old does not reflect the recent improvements found in their overall mortality. Interestingly, it seems that the preventive effect of marriage seems to be ceasing with increasing age.

Age Factors↗

PubMed2002

[Do children of long-lived parents age more successfully?].

INTRODUCTION: Long-lived individuals are rare and may be selected in part for the genetic factors that promote successful ageing. The children of long-lived parents may therefore age more successfully than the children of short-lived parents. MATERIAL AND METHODS: We used three major cross-sectional, population-based surveys to study the association of parental longevity with successful ageing in offspring. The measures of ageing were hand-grip strength, cognitive performance (mini mental state examination (MMSE) and a cognitive composite score), self-reported diseases, and self-rated health. RESULTS: For every additional ten years the parents lived, grip strength increased by 0.32 kg (95% CI = 0.00-0.63), the MMSE score by 0.20 points (95% CI = 0.03-0.37), and cognitive composite score by 0.24 points (95% CI = 0.07-0.40). A ten-year increment of parental life was associated with a reduction by approximately 0.20 in the adjusted OR for having each of the following conditions: diabetes, hypertension, ischaemic heart disease, heart failure, stroke, or fair, poor or very poor self-rated health. Almost all the effects were seen solely in the cohort of 70+ year-olds, but not in the middle-aged or nonagenarians. DISCUSSION: Parental life span is positively associated with physical and cognitive functioning and avoidance of some of the common chronic diseases. However, overall the effects are small and are seen in the elderly, but not in the middle-aged or the very old.

Adult Children↗

PubMed2002

High age-adjusted prevalence of Parkinson's disease among Inuits in Greenland.

The prevalence of PD among Inuits in Greenland has not been determined. The authors found 40 patients with PD at the prevalence date January 1, 2000. The crude prevalence of PD was estimated to be 81.0 per 100.000 inhabitants born in Greenland. However, owing to the low proportion of 50+ year old Inuits (16.5 vs 33.5% in Denmark) the age-adjusted prevalence was much higher-187.5 per 100,000 persons.

Age Distribution↗

PubMed2002

Living longer--but better?

The highest attained age has increased by about 20 years since the beginning of the 19th century. In the course of the 1990s, more than ten individuals reached 115 years or more, including Jeanne Calment who attained the age of 122 years. In low-mortality countries, the number of centenarians has doubled every decade since 1950. This dramatic increase was mainly due to periodical effects related to the drastic fall in mortality among the elderly. The fact that centenarians are survivors does not mean that they are healthy. A high prevalence of comorbidity is found, and many centenarians have survived major diseases thanks to medical treatment and surgery. It is, however, possible that the comorbidity is less serious than in younger elderly. Certain personality traits may also be important in surviving health-threatening conditions. Furthermore, a number of biological and cognitive functions seem to be well-preserved in several centenarians. The influence of the apoE-gene and other genes involved in fundamental mechanisms illustrates that with advancing age and increasing mortality even small risks may have a substantial effect on survival to 100 years. A small proportion of long-livers may be considered as relatively autonomous, and this proportion will probably increase in the future. We are living longer and seem to postpone the terminal dependent phase to higher ages. Longevity may thus be perceived as part of our postmodern condition with its mix of pleasure and suffering.

Aged↗

PubMed2002

Reproduction life history and hip fractures.

PURPOSE: The present study assesses the association between reproduction and hip fractures. METHODS: We used two surveys on elderly Danish twins of both sexes and the Danish National Register of Patients. In a cross-sectional study of 2045 twins aged 75-98 years in 1995, we studied the association between different aspects of reproduction and hip fractures leading to hospitalization between 1977 and 1994. In a prospective study, 3057 twins aged 66-99 years in 1977 were followed for a total of 29,112 years, and the association between number of children and incidence of hip fractures was investigated. RESULTS: In the cross-sectional study, as well as the prospective study, we found, for both sexes, that having no children was associated with a higher risk of hip fracture compared to having at least one child. When excluding persons without children, we found no effect of number of birth events/children. In the cross-sectional study, we found no effect of birth interval length or age at first birth. For women, we found an effect of age at last birth. CONCLUSIONS: No "cost-of-reproduction" in terms of hip fractures was observed. On the contrary, we found that having one or more children was associated with a lower risk of hip fracture.

Aged↗

PubMed2002

The dose-response curve of the gravitropic reaction: a re-analysis.

The dose-response curve of the gravitropic reaction is often used to evaluate the gravisensing of plant organs. It has been proposed (Larsen 1957) that the response (curvature) varies linearly as a function of the logarithm of the dose of gravistimulus. As this model fitted correctly most of the data obtained in the literature, the presentation time (tp, minimal duration of stimulation in the gravitational field to induce a response) or the presentation dose (dp, minimal quantity in g.s of stimulation to induce a response) were estimated by extrapolating down to zero curvature the straight line representing the response as a function of the logarithm of the stimulus. This method was preferred to a direct measurement of dp or tp with minute stimulations, since very slight gravitropic response cannot be distinguished from the background oscillations of the extremity of the organs. In the present review, it is shown that generally the logarithmic model (L) does not fit the experimental data published in the literature as well as the hyperbolic model (H). The H model in its simplest form is related to a response in which a ligand-receptor system is the limiting phase in the cascade of events leading to the response (Weyers et al. 1987). However, it is demonstrated that the differential growth, responsible for the curvature (and the angle of curvature), would vary as a hyperbolic function of the dose of stimulation, even if several steps involving ligand-receptor systems are responsible for the gravitropic curvature. In the H model, there is theoretically no presentation time (or presentation dose) since the curve passes through the origin. The value of the derivative of the H function equals a/b and represents the slope of the cune at the origin. It could be therefore used to estimate gravisensitivity. This provides a measurement of graviresponsiveness for threshold doses of stimulation. These results imply that the presentation time (or presentation dose) derived from the L model cannot be used anymore as an estimate of gravisensitivity. On the contrary, the perception time (minimal duration of a repeated stimulation which induces a response), which is less than 1 s, should be related to the perception of gravity. The consequences of these results on the mode of action and the nature of graviperception are discussed.

Journal Article↗

PubMed2002

C-reactive protein: a serological marker for preterm delivery?

BACKGROUND: We studied the association between the C-reactive protein level in the maternal serum early in the second trimester with that in preterm delivery. METHODS: The present study is a prospective nested case-control study including 84 singleton, preterm deliveries (cases) and 400 singleton, term deliveries (controls), based at the Odense University Hospital, Denmark. These cases were identified from a cohort of 2846 women, monitored from their first prenatal care visit until their delivery. All the participants were examined at enrollment (median 16.3 weeks of gestation). Conventional statistical methods were used for analyses. RESULTS: We found statistically significant differences in the C-reactive protein levels measured in early pregnancy between the women delivering preterm and those delivering at term. Different statistically significant odds ratios of between 1.7 and 2.0 were calculated, depending on the C-reactive protein level's cut-off value, and ranged from 5.6 mg/l (75th percentile) to 16.4 mg/l (95th percentile). The highest level was achieved at the 85th percentile (7.6 mg/l); odds ratio 2.0 (95%CI, 1.2-3.5). CONCLUSION: A high C-reactive protein level at the beginning of a pregnancy is associated with a nearly twofold increased risk of preterm delivery; however, the clinical value at this point is still limited.

Adult↗

PubMed2002

Proinflammatory cytokines, antibodies to Chlamydia pneumoniae and age-associated diseases in Danish centenarians: is there a link?

Plasma levels of tumour necrosis factor (TNF)-alpha levels increase with age. High levels are associated with dementia and atherosclerosis in centenarians. Chlamydia pneumoniae induces the production of proinflammatory cytokines and has been related to the pathogeneses of Alzheimer's disease and cardiovascular diseases. The purpose of this study was to test the hypothesis that circulating levels of TNF-alpha represent a link between C. pneumoniae, high prevalences of dementia and cardiovascular diseases in 126 Danish centenarians. IgA antibody titres against C. pneumoniae were linearly correlated with high plasma levels of TNF-alpha in centenarians. However, both parameters were also correlated with total IgA in the blood and the association between C. pneumoniae IgA and TNF-alpha was not significant when total IgA was included in a multiple linear regression model. Accordingly, the association between C. pneumoniae-specific IgA and TNF-alpha may reflect immune activation rather than a specific antibody response. No associations were found between antibodies to C. pneumoniae and dementia or cardiovascular diseases. Although TNF-alpha is likely to be involved in the pathogenesis of atherosclerosis and dementia, the present study does not support the hypothesis that TNF-alpha represents a link between chronic C. pneumoniae infection and these disorders.

Aged↗

PubMed2002

Study of homeosis in the flower of Philodendron (araceae): a qualitative and quantitative approach.

This study deals specifically with floral organogenesis and the development of the inflorescence of Philodendron squamiferum and P. pedatum. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. An intermediate zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the sterile male and female floral zones. In general, the portion of bisexual flowers facing the male zone forms staminodes, and the portion facing the female zone develops an incomplete gynoecium with few carpels. The incomplete separation of some staminodes from the gynoecial portion of the whorl shows that they belong to the same whorl as the carpels. There are two levels of aberrant floral structures in Philodendron: The first one is represented by the presence of atypical bisexual flowers, which are intermediates between typical female flowers and typical sterile male flowers. The second one is the presence of intermediate structures between typical carpels and typical staminodes on a single atypical bisexual flower. The atypical bisexual flowers of P. squamiferum and P. pedatum are believed to be a case of homeosis where carpels have been replaced by sterile stamens on the same whorl. A quantitative analysis indicates that in both species, on average, one staminode replaces one carpel.

Flowers↗

PubMed2002

A case-only approach for assessing gene by sex interaction in human longevity.

As one aspect of the complex feature of longevity, gene by sex interaction plays an important role in influencing human life span. With advances in molecular genetics, more studies aimed at assessing gene by sex interaction are expected. New and valid statistical methods are needed. In this article, we introduce a nontraditional approach, the case-only design, which was originally proposed for assessing gene and disease associations, to detect gene by sex interaction in human longevity. Applications of this method to data collected from centenarian studies show that it can produce consistent results as compared with results obtained from case-control and other approaches. The method cannot be used as a substitute for traditional case-control studies since it is limited to the detection of interactions only. However, the easily applicable case-only approach can be an important tool for screening many potential genes that contribute to human longevity.

Aged↗

PubMed2002

Do children of long-lived parents age more successfully?

BACKGROUND: Long-lived individuals are rare and may be selected in part for the genetic factors that promote successful aging. The children of long-lived parents may therefore age more successfully than the children of short-lived parents. METHODS: We used three major cross-sectional population-based surveys to study the association of parental longevity with successful aging in offspring. The measures of aging were hand-grip strength, cognitive performance (Mini Mental State Examination and a cognitive composite score), self-reported diseases, and self-rated health. RESULTS: For every additional 10 years the parents lived, their children's grip strength increased by 0.32 kg (95% CI = 0.00-0.63), Mini Mental State Examination score by 0.20 points (95% CI = 0.03-0.37), and cognitive composite score by 0.24 points (95% CI = 0.07-0.40). A 10-year increment of parental life was associated with a reduction by approximately 0.20 in the adjusted odds ratio for their children having each of the following conditions: diabetes; hypertension; ischemic heart disease; heart failure; stroke; or fair, poor, or very poor self-rated health. Almost all the effects were seen solely in the cohort of 70+-year-olds, but not among middle-aged or nonagenarian subjects. CONCLUSIONS: Parental life span is positively associated with the children's physical and cognitive functioning and avoidance of some of the common chronic diseases. However, the effects are small and are seen among offspring who are elderly, but not among the middle-aged or the oldest old.

Age Distribution↗

PubMed2002

Cognitive impairment and mortality among nonagenarians: the Danish 1905 cohort survey.

Cognitive impairment has been associated with increased mortality. Most studies, however, have only included small numbers, if at all, of the very old. In a large nationwide survey of all Danes born in 1905 and still alive in 1998, where the baseline examination was conducted, we examined the impact of cognitive impairment on mortality over a 2-year period. No cognitive impairment was defined as a score of 24-30 points on the Mini Mental State Examination, mild cognitive impairment was defined as a score of 18-23 points, and severe impairment was defined as a score of 0-17 points. Cox regression analysis was applied to adjust for a number of known and suspected factors known or suspected of being associated with cognition and mortality (e.g. sociodemographic factors, sex, smoking, alcohol consumption, depressive symptoms, and physical abilities), and yielded hazard ratios (95% confidence interval) of 1.24 (1.00-1.55) for mildly impaired and 1.73 (1.37-2.20) for severely impaired Danes compared to individuals with no impairment. Cognitive impairment predicts mortality among the very old, even after controlling for most known predictors of mortality.

Aged↗

PubMedDate not supplied

High circulating levels of tumor necrosis factor-alpha in centenarians are not associated with increased production in T lymphocytes.

BACKGROUND: Aging is characterized by increased inflammatory activity reflected by increased plasma levels of proinflammatory cytokines, concomitant with an altered cytokine profile of T lymphocytes. High plasma levels of tumor necrosis factor (TNF)-alpha are strongly associated with morbidity and mortality in elderly humans. However, the cellular source and mechanisms for the increased circulating TNF-alpha levels are unknown. OBJECTIVE: The aim of the present study was to investigate if high plasma levels of TNF-alpha are associated with increased production of TNF-alpha by T lymphocytes in elderly humans. METHODS: TNF-alpha production by CD4+ and CD8+ T lymphocytes was measured by flow cytometry following stimulation with phorbol 12-myristate 13-acetate and ionomycin in 28 young controls, 14, 81-year-olds and 25 centenarians. RESULTS: Plasma levels of TNF-alpha increased with increasing age. An increased percentage and number of T lymphocytes from the 81 year olds expressed TNF-alpha, whereas centenarians did not show this altered TNF-alpha secretion profile. CONCLUSION: T cells may contribute to the elevated levels of plasma TNF-alpha in healthy elderly subjects, whereas other mechanisms are responsible in very old individuals.

Adult↗

PubMedDate not supplied

Complexity and information in regular and random phyllotactic patterns.

In biology, the theory of information has been used to study the degree of order of many living systems. Different concepts of entropy have been applied to the analysis of phyllotaxis. In the present paper we will determine the degree of order of disorganized patterns by using informational entropy concepts deduced from the work of Brillouin, Shannon, and Yagil. As case studies, we will apply these concepts of entropy to the disorganized patterns found in mutants of Arabidopsis. The calculation of entropy gives a precise idea of the degree of order of a phyllotactic system.

Biology↗