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At least 415 records · Page 23Linked to original sources
PubMed2002

Amygdala or ventral hippocampal lesions at two early stages of life differentially affect open field behaviour later in life; an animal model of neurodevelopmental psychopathological disorders.

Psychiatric disorders like schizophrenia or autism are thought to result from disruption of the normal pattern of brain development. Abnormalities in the amygdaloid complex and hippocampus have been reported in these disorders. In the present study rats were lesioned in the amygdala or ventral hippocampus on day 7 of life (immature brain) or day 21 of life (almost mature brain) and open field behaviour was determined later in life before and after puberty. Lesioning on day 7 resulted in behavioural changes, interpreted as locomotor stereotypy and decreased anxiety in case of amygdala or hippocampus, respectively. These effects were more profoundly present after puberty. Lesioning on day 21 did not result in these behavioural changes, which subscribes to the importance of the stage of brain maturation on functional development. The results suggest that the behavioural changes in rats lesioned on day 7 may due to a malfunctioning of structures connected to the amygdala or ventral hippocampus. Brain lesions made on day 7 of life may serve as a potential model of psychopathological neurodevelopmental disorders.

Aging↗
PubMed2000

Shelf life of modified atmosphere packed cooked meat products: addition of Na-lactate as a fourth shelf life determinative factor in a model and product validation.

Cooked meat products are often post-contaminated because of a packaging and/or slicing step after the pasteurisation process. The shelf life is therefore limited and can be extended by adding Na-lactate. A previously developed model for the spoilage of gas packed cooked meat products, including temperature, water activity and dissolved CO2 as independent variables, was extended with a fourth factor: the Na-lactate concentration in the aqueous phase of the meat product. Models were developed for the maximum specific growth rate mu(max) and the lag phase lambda of the specific spoilage organism Lactobacillus sake subsp. carnosum. Quadratic response surface equations were compared with extended Ratkowsky models. In general, response surface equations fitted the experimental data best but in the case of mu(max) the response surface model predicted illogical growth behaviour at low water activities and high Na-lactate concentrations. A extensive product validation of the mathematical models was performed by means of inoculated as well as naturally contaminated industrially prepared cooked meat products. The deviations of the experimentally determined versus predicted growth parameters in inoculated cooked meat products were in general small. Both types of models were also able to predict the shelf life of naturally contaminated cooked meat products, except for pâté where an under-estimation of the shelf life was predicted by the response surface equations. The validation studies revealed higher accuracy of the extended Ratkowsky models in comparison to the response surface equations. A significant shelf life extending effect of Na-lactate was predicted, which was more pronounced at low refrigerated temperatures. A synergistic effect has also been noticed between Na-lactate and carbon dioxide which, at least partly, could be explained by the pH-decreasing effect of CO2.

Animals↗
PubMed2001

Long-term, progressive hippocampal cell loss and dysfunction induced by early-life administration of corticotropin-releasing hormone reproduce the effects of early-life stress.

Stress early in postnatal life may result in long-term memory deficits and selective loss of hippocampal neurons. The mechanisms involved are poorly understood, but they may involve molecules and processes in the immature limbic system that are activated by stressful challenges. We report that administration of corticotropin-releasing hormone (CRH), the key limbic stress modulator, to the brains of immature rats reproduced the consequences of early-life stress, reducing memory functions throughout life. These deficits were associated with progressive loss of hippocampal CA3 neurons and chronic up-regulation of hippocampal CRH expression. Importantly, they did not require the presence of stress levels of glucocorticoids. These findings indicate a critical role for CRH in the mechanisms underlying the long-term effects of early-life stress on hippocampal integrity and function.

Animals↗
PubMed2002

Does the rapid appearance of life on Earth suggest that life is common in the universe?

It is sometimes assumed that the rapidity of biogenesis on Earth suggests that life is common in the Universe. Here we critically examine the assumptions inherent in this if-life-evolved-rapidly-life-must-be-common argument. We use the observational constraints on the rapidity of biogenesis on Earth to infer the probability of biogenesis on terrestrial planets with the same unknown probability of biogenesis as the Earth. We find that on such planets, older than approximately 1 Gyr, the probability of biogenesis is > 13% at the 95% confidence level. This quantifies an important term in the Drake Equation but does not necessarily mean that life is common in the Universe.

Earth, Planet↗
PubMed2006

Relationship with others and life satisfaction in later life: do gender and widowhood make a difference?

In this study we investigated whether social relationship is a stronger determinant of life satisfaction in older women than in older men, and whether this is more obvious in widowed than in married persons, in a representative sample of Chinese individuals aged 60 or older in Hong Kong (N=1,616). We tested the moderating effect of gender and widowhood by means of a multigroup analysis in structural equation modeling that incorporated other major predictors of life satisfaction. Consistent with predictions, relatedness was much more important for women than for men. Furthermore, relatedness was the most important determinant of life satisfaction in women, regardless of marital status, but it was only a moderate predictor in married men, and even an irrelevant factor in widowers. We discuss the results in terms of how gender roles shape relationship goals, and thus how men and women evaluate life satisfaction differently in the context of relationship with others.

Age Factors↗
PubMed1975

Mid-life temperature-transfer effects on life-span of annual fish.

When annual fish are transferred from 20 C. to 15 C. at slightly less than the midpoint of lifespan of those kept throughout life at 20 C., the survival of the transferees exceeds theoretical expectations. They live longer than those maintained throughout life at 15 C., which had previously manifested the longest survival. These results indicate that the influence of temperature on life-span is not uniform throughout the life of a poikilothermic vertebrate. The phenomenon of partial temperature-independency had been previously demonstrated in invertebrates.

Aging↗
PubMed2002

What's end of life got to do with it? Research ethics with populations at life's end.

PURPOSE: This study addressed key concerns that gave rise to the question of whether special guidelines were needed to monitor research at the end of life. DESIGN AND METHODS: Summary of established ethical and legal guidelines that govern the conduct of research with human subjects, with discussion of issues relevant to populations at life's end. Discussion of whether special guidelines are indicated focuses on four questions concerning: (a). time periods; (b). methods and approaches; (c). informed consent; and (d). obligations of researchers. RESULTS: Although research involving patients at end of life does present important ethical and moral challenges to researchers and should be scrutinized carefully by institutional review boards (IRBs), special guidelines are not required. IMPLICATIONS: Closer examination of the dimensions discussed will enhance the research endeavor and model the qualities for which end-of-life research should become known.

Aged↗
PubMedDate not supplied

Distinguishing between life-saving and life-sustaining treatments: when the physician and spouse disagree.

There is a fine distinction between life-saving measures and life-sustaining ones. In the case presented below the husband of a wife with cancer did not understand the continuation of life-sustaining treatment after the decision to reject life-saving measures was made. This resulted in a conflict between the husband and physician that placed the nurse, as family advocate, in the middle. The case is followed by an analysis with recommendations on how to handle this type of situation.

Adult↗
PubMed2003

Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

Adipose Tissue↗
PubMed1996

Dimensions of life meaning: a qualitative investigation at mid-life.

Meaning in life is integral to psychological functioning. Empirical research into this construct has focused on sources of meaning. Reker & Wong (1988) have proposed a theoretical outline for a multidimensional structure of meaning which challenges a source-based approach. The present study used a qualitative approach to explore people's accounts of their experiences of life meaning and focused on the following key dimensions: sources; cognitive, motivational and affective components; breadth; and depth. Thirty-eight adults at mid-life were interviewed in depth. Five categories of sources accounted for material reported in previous studies, but a sixth was required to contain experiences of meaning relating to the natural environment. All sources revealed cognitive, motivational and affective components. Accounts showed variation in breadth and depth of meaning, although the assessment of depth proved problematic. Results from this qualitative exploration generally confirm Reker & Wong's structural model. Furthermore, many people have coherent frameworks of meaning which structure their life experiences, and serve to integrate these theoretical dimensions.

Adult↗
PubMed1993

Guidelines for basic life support. European Resuscitation Council Basic Life Support Working Group.

A basic life support working group of the European Resuscitation Council was set up in 1991. It was given the objective of producing agreed standards of basic life support to ensure uniform teaching of the techniques to health care professionals and lay people throughout Europe. A common complaint in the past, particularly from members of the public who have received instruction in basic life support, is that different organisations teach different techniques. This problem exists within countries as well as among countries. The European Resuscitation Council presents below its basic life support guidelines, which it hopes will be detailed enough to avoid any ambiguities and to be acceptable for use in all the countries represented by the council.

Cardiopulmonary Resuscitation↗
PubMed2005

Further study of prolongation of life span associated with immunological modification by chronic low-dose-rate irradiation in MRL-lpr/lpr mice: effects of whole-life irradiation.

MRL-lpr/lpr mice carry a deletion in the apoptosis-regulating Fas gene that markedly shortens life due to multiple severe diseases. In our previous study (Radiat. Res. 161, 168- 173, 2004), chronic low-dose-rate gamma irradiation of mice at 0.35 or 1.2 mGy/h for 5 weeks markedly prolonged the life span, accompanied by immunological activation. This report shows that extension of the irradiation period to the entire life of the mice at the same dose rates improved survival further. The 50% survival time for untreated mice, 134 days, was prolonged to 502 days by 1.2 mGy/h life-long irradiation. Also obtained were a time course and a radiation dose-rate response for the activation of the immune system as indicated by a significant increase in CD4+ CD8+ T cells in the thymus and CD8+ T cells in the spleen and also by a significant decrease in CD3+ CD45R/B220+ cells and CD45R/B220+ CD40+ cells in the spleen. Drastic ameliorations of multiple severe diseases, i.e. total-body lymphadenopathy, splenomegaly and serious autoimmune diseases including proteinuria, and kidney and brain-central nervous system syndromes, were found in parallel with these immunological activations, with lifelong low-dose-rate irradiation being more effective than 5-week irradiation at low dose rates.

Adaptation, Physiological↗
PubMedDate not supplied

The female life course: life situations and perception of control.

The adult life course can be divided into socially defined age status periods differentiated not only by members' chronological age, but also by their experience within the family and work life cycles and degree of socially accorded rights, power, and privilege. The effects of individuals' social age status (adolescence, adulthood, retired adulthood) and gender on subjective perception of control and personal efficacy in familiar life situations from three domains (work, home, school) are examined within a multivariate cohort study. Results indicate that the adults, regardless of gender, perceived the greatest direct personal control or indirect control through the ability to influence powerful others. The adult females perceived a greater degree of influence on powerful others than adolescent or retired females, but the same as males of any status period. The implications of these results for the female life course are discussed.

Achievement↗
PubMed1999

[Life-span developmental processes from the point of view of the elderly: an examination of vocational life].

The purpose of this study was to examine the experiences and meanings of crises and to clarify types of the vocational life-cycle the elderly recognized in life review. Subjects were 50 elderly persons at home (male: 39, female: 11, 66-79 years old), who took part in an individually semi-structured interview. Vocational life processes involved school decision making, career decision making, career development, retirement, and final retirement from the work. As a result, more than 50% of the elderly had experienced crises at final school decision making, and with career development in their thirties' and forties'. Moreover, four types of vocational life-cycles were found. They were the appreciating type, the decision making type, the career development type, and the moderate type. The appreciating type was further sub-categorized into the consistent type, the modifying type, the overcoming type and the unfolding type. Finally, relationships between these types and attitudes toward retirement were examined. Positive attitudes toward retirement were high in the consistent type, while negative attitudes were high in the modifying type.

Aged↗
PubMed1983

The measurement of stress-inducing life events and life styles: questions of conceptual independence and discriminant validity.

Research on psycho-social sources of coronary heart disease (CHD) has focused on two basic ideas: on the one hand that CHD is the result of the accumulation of stress-inducing events and, on the other hand, that CHD stems from the way in which individuals live their lives and respond to events that do occur. While it is relatively easy to separate these ideas at the conceptual level, the research reported here indicates that the two most prominent operationalizations of life situation and life style share some degree of commonality in their domains. Specifically, a comparison of the responses of 205 individuals indicate that variations in scores on the Jenkins Activity Survey are associated with variations in scores on subjective but not objective items on the Recent Life Changes Questionnaire. The implications of these results for the study of psycho-social factors in CHD are discussed.

Adult↗
PubMed1997

Regional patterns of disability-free life expectancy and disability-adjusted life expectancy: global Burden of Disease Study.

BACKGROUND: Information on non-fatal health outcomes of disease and injury has been largely neglected in health planning because of the conceptual and definitional complexity of measuring morbidity and disability in populations. One of our major objectives was to quantify disability for inclusion in health policy debates. We analysed these health outcomes in terms of disability-free life expectancy (DFLE) and disability-adjusted life expectancy (DALE). METHODS: Published and unpublished data were systematically reviewed to estimate the incidence, prevalence, and duration of 483 disabling sequelae of 107 diseases and injuries. To ensure internal consistency of these estimates, a software programme (DISMOD) was applied many times until consistent parameters were identified. The severity of disability, on a scale of 0 (perfect health) to 1 (death), was measured in a deliberate manner by the person-trade-off method. Spearman's and Pearson's correlation coefficients were used to measure disability weights among groups. Prevalence of seven classes of disability was back-calculated from the distribution of each disabling sequela across disabilities. Prevalence for each class of disability for different age-sex groups was used to calculate seven forms of DFLE and DALE based on Sullivan's method. FINDINGS: Prevalence of most disability classes is highest in sub-Saharan Africa and lowest in established market economies. Low-severity disabilities (class I and class II) are the most common. The expectation at birth of class I disability ranges from 6.5 years in established market economies to 14.7 years in sub-Saharan Africa, and for class II disabilities, from 8.5-18.4 years. DFLE varies significantly among regions: DFLE for class I disabilities at birth ranges from 9.9 years in sub-Saharan Africa to 47.7 years in established market economies for females and DFLE for class V disabilities ranges from 43.4 years for men in sub-Saharan Africa to 74.8 years for women in established market economies. The proportion of expected life span at birth lived with disability adjusted for severity, varies from about 8% in established market economies to 15% in sub-Saharan Africa, with little difference between men and women. In high-income regions, nearly 90% of expected disability is due to non-communicable diseases and most of the remainder to injuries. In poorer regions, almost half of expected disability is due to communicable diseases and injuries. INTERPRETATION: The higher proportion of lifespan spent disabled in high-mortality populations is consistent with the compression of morbidity hypothesis. The threshold definition of disability used substantially affects the results of DFLE, DALE, which incorporates severity weights for disabilities, is a useful summary measure of the burden of disability and mortality.

Adolescent↗
PubMed2000

Income-related inequality in life-years and quality-adjusted life-years.

We estimate the income-related inequality in Sweden with respect to life-years and quality-adjusted life-years (QALYs). We use a large data set from Sweden with over 40,000 individuals followed up for 10-16 years, to estimate the survival and quality-adjusted survival in different income groups. For both life-years and QALYs, we discover inequalities in health favouring the higher income groups. For men (women) in the youngest age-group (20-29 years), the number of QALYs is 43.7 (45.7) in the lowest income decile and 47.2 (49.0) in the highest income decile.

Adult↗
PubMed2002

Prehospital advanced life support provided by specially trained physicians: is there a benefit in terms of life years gained?

BACKGROUND: The benefit of prehospital advanced life support (ALS) is disputed, as is the prehospital use of specially trained, hospital-based physicians. The purpose of the study was to assess the health benefit from an anesthesiologist-manned prehospital emergency medical service (EMS), and to separate the benefit of the anesthesiologist from that of rapid transport. METHODS: The anesthesiologist-manned helicopter and rapid response car service at Rogaland Central Hospital assisted 1106 patients at the scene during the 18-month study period. Two expert panels assessed patients with a potential health benefit for life years gained (LYG) using a modified Delphi technique. The probability of survival as a result of the studied EMS was multiplied by the life expectancy of each patient. The benefit was attributed either to the anesthesiologist, the rapid transport or a combination of both. RESULTS: The expert panels estimated a benefit of 504 LYG in 74 patients (7% of the total study population), with a median age of 54 years (range 0-88). The cause of the emergency was cardiac diseases (including cardiac arrest) in 61% of the 74 patients, trauma in 19%, and cardio-respiratory failure as a result of other conditions in 20%. The LYG were equally divided between air and ground missions, and the majority (88%) were attributed solely to ALS by the anesthesiologist. CONCLUSION: The expert panels found LYG in every 14th patient assisted by this anesthesiologist-manned prehospital EMS. There was no difference in LYG between the helicopter and the rapid response car missions. The role of the anesthesiologist was crucial for health benefits.

Adolescent↗