What Do Chronologically Aged Cells Die From

The chronological life span of a yeast cell begins under conditions highly favorable for growth low cell density, optimal temperature, high nutrient availability, and the presence of a preferred carbon source (glucose). These conditions allow cells to enter an exponential growth phase, during which cells generate ATP primarily through glycolysis and fermentation of pyruvate to ethanol. As glucose becomes depleted, yeast cells progress through the diauxic shift, a growth phase characterized by...

Antiinflammatory Approaches

Inflammation in stroke is characterized by the accumulation of leukocytes and activation of resident microglial cells. Inflammatory cells can contribute to stroke pathology through two basic mechanisms they form aggregates in the venules after reperfusion or enter infarcted tissue and exacerbate cell death through production of free radicals and cytokines. Cell adhesion molecules such as selectins, integrins, and ICAMs permit endothelial-inflammatory cell interactions. Treatment with...

The Belmont Report

The Belmont Report begins by recognizing that while research involving human subjects has produced important social benefits including reduced morbidity, greater longevity and improved quality of life, this research has also posed challenging and troubling ethical questions. The report also explicitly distinguishes clinical practice and medical research. The purpose of clinical practice is to enhance the well-being of the patient by using interventions for which there is an expectation for...

Research Involving Elderly Persons With Impaired Decisionmaking Capacity

Approximately 10 percent of elders older than 65 years and 22 percent older than 80 years have dementia. Furthermore, a majority of nursing home residents have some form of cognitive impairment (Cassel, C., 1988). In addition, many elders experience delirium during hospi-talizations for acute illnesses (Rummans, T., et al., 1995). Many of these patients are incapable of giving valid informed consent. Nevertheless, to better understand illnesses that uniquely afflict elders including those...

Bats as Models for Aging Research Advantages and Disadvantages

Uncovering differences and similarities in patterns of aging among various organisms from a broad phylo-genetic spectrum is likely to yield insight into universal mechanisms of senescence. The inclusion of out-groups in aging research would allow investigators to assess whether these mechanisms or traits are unique to a given study species or shared by a broader taxonomic group (Austad, 1997). Bats may be an excellent out-group because they share life history traits with primates and other...

Psychological Aging A Contextual View

Lang In this chapter we review theories on the psychological dynamics of person-environment relations as people age. The chapter begins with an introduction to the issue of aging in context by contrasting perspectives of the biology of aging, the social sciences, and psychological gerontology. We also consider the historical background important for the understanding of a contextual view of aging in the evolution of gerontology, as well as introduce core theory...

References

Altman, PL., and Dittmer, D.S. (1972). Biology Data Book, Vol. 1. Federation of the American Sciences for Experimental Biology, Bethesda, MD. Austad, S. (1997). Birds as models of aging in biomedical research. ILAR J. Online 38(3). Austad, S.N. (1993). The comparative perspective and choice of animal models in aging research. Aging (Milano) 5, 259-267. Austad, S.N., and Fischer, K.E. (1991). Mammalian aging, metabolism, and ecology Evidence from the bats and marsupials. J. Gerontol. Biol. Sci....

Aging Immunity Importance Of Innate Immunity In Zebrafish

Finch and Crimmins proposed that the reduction in lifetime exposure to infectious diseases and other sources of inflammation has made an important contribution to the historical decline in old-age mortality (Finch and Crimmins, 2004). This will likely also be true in zebrafish, because one of the most critical problems in their husbandry late in life derives from multiple microbial infections. Resistance to microbial infectious diseases obviously declines with age in adult zebrafish. The...

Autonomy and Protection of Older Adults in Research How Much Is Enough

The aging process presents some unique challenges to respect for autonomy among older adults, particularly in relation to obtaining informed consent and in the research environment those challenges are even more exquisitely complex. We will consider three possibilities that correspond roughly to the variations in decision-making capacities of older adults. The first two possibilities address recognizing and supporting the capacity of older adults to consent to research. The third addresses the...

Biomarkers of Healthy Eating

Biomarkers are used to assess nutritional intakes and nutritional status because they are believed to provide more accurate estimates of intake bioavailability of specific nutrients, especially where these are combined (as in most meals) or cooked to variable extent. There are also concerns about the validity of food composition tables when foods are known to vary over time (as with industrialized food processing) or cultivated in different soils or climatic conditions. Although some...

Heritability Estimates

Twin studies have estimated the heritability of life expectancy to range between 25 and 30 (McGue, Vaupel, Holm, and Harvald, 1993). These twin studies cannot infer the heritability of living to extreme old age because the oldest subjects in these studies are only octogenarians. In contrast, centenarians who live an additional 15 to 20 years beyond average life expectancy may require more than an advantage in their habits and environment. They may require a genetic advantage that translates...

Energy Balance and Body Composition

Although we are seeing a marked increase in the number of elderly subjects in the population who are either overweight or obese, it is important to recognize that involuntary weight loss is a common feature of aging and is more common than weight gain. There are a number of reasons for this weight loss, including increased energy expenditure and decreased appetite arising from disease states that are common in the elderly. Involuntary weight loss in the elderly is associated with functional...

Biochemical Studies Of Agerelated Cataracts

Crystallin modifications associated with cataracts The lens crystallins are a major potential target for accumulating damage associated with age-related cataracts, although there are certainly others. Thus, as the crystal-lins accumulate modifications and damage over the lifetime of an individual, their ability to participate in appropriate intermolecular interactions, and even to remain in solution, decreases. Whether proteins in age-related cataracts become insoluble as a result of complete...

Telomeric Aging Markers

All vertebrate telomeres contain a characteristic 6-base repeated sequence, TTAGGG (Meyne et al., 1989). According to the telomere hypothesis, DNA replication in somatic cells leads to telomere shortening, which forms the basis of a cellular mitotic clock (Sherr and DePinho, 2000). Moreover, several premature aging syndromes lead to accelerated loss of telomeric DNA, which eventually results in accelerated replicative senescence of the cells (Kipling et al., 2004 Metcalfe et al., 1996 Pandita,...

Herd Immunity

Herd immunity is essentially a simple concept describing the totality of naturally acquired and vaccine-based immunity to a given infectious agent as a proportion of the whole population. While the individual objective of vaccination is clearly to prevent or reduce the risk of infection for the individual concerned, the public health objective of vaccination is to increase the level of herd immunity to that required for control or elimination of the infection from the population, and in the...

Husbandry Of The Rhesus Macaque

There are extensive data on the maintenance of the rhesus macaque in laboratory conditions as well as in outdoor pens. The type of housing may vary with the experimental paradigm and the objectives of the study. In the case of studies in which diet or other interventions are used to determine effects during aging, animals are likely to be housed individually in standard primate caging that meet the NIH Guide for the Care and Use of Laboratory Animals. Studies in which social behavior and family...

Sequential Sound Segregation

A second form of primitive grouping takes place along the time axis, and auditory streaming acts as a striking psychophysical demonstration of how sequential sound segregation works (see Figure 64.2C). In a typical experiment, participants are presented with ABA ABA sequences in which A and B are sinusoidal tones of different frequencies and is a silent interval. The frequency separation between the A and B tones is manipulated to promote either the perception of a single gallop-like rhythm...

Transgenic Models Of Hypertension

The use of transgenic animal models to study the role that specific genes play in causing hypertension has been a focus of much research. However, to our knowledge there are no studies in which the mice were allowed to age. With the exception of a few models that are severely hypertensive and will not survive more than a few weeks or months, the lack of data in aging hypertensive trans-genics likely reflects the specific interest of the investigators who developed the strains that is, the...

T Cells

Similar to B cell development, T cell development undergoes several stages and can be followed by the combined expression of specific cell-surface receptors. Certain cell-surface markers have different expression patterns in humans and mice. For example, Thy-1, an Ig-like glycoprotein, is present on both thymocytes and peripheral T cells in mice but only on rat thymocytes (Tokugawa et al., 1997). In humans, Thy-1 expression is found only on stem cells and disappears from thymic progenitors....

Methods of Age Determination in Bats

Bats are difficult to age once they reach adulthood, and the currently available methods of age determination have several limitations. To begin with, bats show no visible markers of aging, and the few traits that have been correlated with age to establish reference standards show significant variation due to genetic structuring of populations and environmental variation which impacts development. Additionally, available reference standards lack data from very old bats, likely because the...

Rpe Cells

As previously stated, postmitotic cells perform numerous metabolic functions throughout our lives, not only for themselves, but also for the photoreceptors. From about 20 years of age, the RPE cells show alteration as a result of their constant activity in the course of the years. Each single RPE cell metabolically supports around 30 photoreceptors (Dryja et al., 1998). Everyday, 10 to 15 of the acromeres of each rod are phagocyted by the RPE cells and replaced. The highest turnover of...

Age Related Hippocampa Dysfunction Early Alzheimers Disease vs Normal Aging

As we age, all of us will experience an inexorable slide into forgetfulness. Age-related memory decline localizes, in part, to the hippocampal formation, a brain circuit made up of separate but interconnected hippocampal subregions. Human studies have established that Alzheimer's disease targets the hippocampal circuit early in its course, and since Alzheimer's disease affects older individuals it is one cause of age-related hippocampal dysfunction. Animal studies, however, have established...

Experimental Models Linking Diabetes Mellitus to Aging and Longevity

In some species, caloric restriction (CR) is associated with reduction of aging and increased longevity. It was observed that a reduced body size was correlated to an increased life span in mice, dogs, Caenorhabditis elegans, or Drosophila melanogaster. One very recent study could not find a clear general effect of body size on life span (Hafen, 2004 McCulloch et al., 2003). The question has been asked why smaller individuals would live longer. One explanation that has been put forward, mainly...

Augmentation And Novel Treatment Strategies

Lithium has demonstrated some benefits when used as augmentation to antidepressants in older patients, with a 50 response acute rate (Zullino et al., 2001). Lithium augmentation significantly reduced relapse rates compared to antidepressants alone over two years (Wilkinson et al., 2002). However, it is recommended that special care be taken when treating elderly patients with lithium, because of a higher risk of adverse effects. No benefit was seen when total sleep deprivation was added to...

Systems Failure And Reliability Structure

A branch of reliability theory, which studies reliability of an entire system given the reliability of its components and components' arrangement (reliability structure), is called system reliability theory (Rausand and Hoyland, 2003). System reliability involves the study of the overall performance of systems of interconnected components. The main objective of system reliability is the construction of a model that represents the times-to-failure of the entire system based on the life...

Caspase Regulation

Caspase-3 is markedly activated after HI in the immature rat brain (Zhu et al., 2000 Wang et al., 2001 Benjelloun et al., 2003) compared to ischemia in the adult brain (Namura et al., 1998). In P7 rat brain, caspase-3 activation contributes substantially to cell death after ischemia with reperfusion not only in the penumbra but also in the core (Benjelloun et al., 2003 Manabat et al., 2003), and cells with the cleaved active form of caspase-3 colocalize with markers of DNA fragmentation in...

Body Composition Changes And Obesity

Aging is characterized by a profound reshaping of the body composition (Hughes et al., 2004). There is a typical decline in the lean body mass, while the fat cell mass is increasing. The reduction of lean body mass is explained mainly by loss of muscle mass, a process called sarcopenia (Nair, 2005 Clarke, 2004). The decline of muscle mass has been estimated to be about 6 per decade between the age of 30 and 80. The exact cause of this decline is not known, but neuro-endocrine factors, reduced...

Identification of Biomarkers of Zebrafish Aging and Senescence

As has already been mentioned, compared with other model organisms, the aging process of zebrafish is in a very early stage of investigation, and we are currently unable to tell precisely how the fish age physiologically, and what the pathophysiological symptoms and lesions are, in zebrafish aging and in their age-associated diseases, respectively. Therefore, first and foremost, it is important to set forth some principles for evaluating the functional aging process in zebrafish. To determine...

Practical Aspects of Honeybee Research

There are several excellent sources for information on how to establish and maintain an apiary or a honeybee breeding program (e.g., Atkins et al., 1975). Moreover, there are special resources available that describe experimental handling procedures and protocols for behavioral (Frisch, 1967 Seeley, 1995) and physiological (Snodgrass, 1956) data collection. Yet, we will provide a brief overview of tools, protocols and experimental considerations that are of specific relevance for research on...

The Utility Of A Rat Model

Rats provide an excellent and reproducible system in which to study age-related cognitive decline. There are surprising similarities between rodents and humans in the anatomy of brain systems, including those that are particularly vulnerable to cognitive decline during aging (e.g., the medial temporal lobe system). In addition, the availability of rodent subjects, as well as ethical concerns regarding the invasive procedures necessary for neuro-biological research in humans, necessitates the...

Table 223

Extrinsic factors that affect lifespan in Drosophila Heat shock, cold stress, hypergravity, low levels of radiation Prolongs the duration of development time and extends adult lifespan results in smaller adult size Prolongs the duration of development time and extends adult lifespan results in larger adult size Fewer viable eggs and offspring have shorter lifespan Shortens lifespan Virgins live longer than mated flies in both sexes, but the magnitude of increase in lifespan is greater in...

Health Precautions For Researchers Handling Bats

Rabies is a significant concern for researchers handling bats, not because bats exhibit a higher incidence of rabies infection than other wild mammals, but because without prompt treatment rabies is nearly always fatal in humans. The virus is most commonly transmitted via contact with infected saliva through a bite, but other means of transmission include contact of infected saliva and nervous tissue with mucous membranes of the mouth, nose and eyes. There have also been two cases of...

Plasma Adiponectin

Plasma adiponectin concentrations are inversely correlated with body fat content (Havel, 2004) that is, they are lowered in obese patients and animals. Adiponectin exerts an antidiabetic effect by sensitizing insulin action and augmenting fatty acid oxidation in the muscles. It also exhibits an antiatherosclerotic effect by attenuating inflammatory insults in the vascular wall. These metabolic and anti-inflammatory effects are also thought to be some of the beneficial effects of CR (Masoro,...

Statistical Issues for Longevity Studies in Animal Models

Keith, Kevin R. Fontaine, and David B. Allison In this chapter we provide an overview of basic statistical concepts and procedures that are germane to researchers interested in aging. We include discussions of hypothesis testing, research design, statistical power, data collection, statistical significance, parametric and nonpara-metric statistical methods, and choosing an appropriate statistical test. We also provide brief introductions to the different types of data...

Protein Kinase C Activation

In recent years, protein kinase C has emerged as a potential target for therapeutic agents that reduce the risk of complications in diabetes. PKC is a calcium-dependent enzyme involved in signal transduction through changes in the phosphorylation of key cellular proteins. High blood glucose levels increase phospholipase D activity, which in turn, activates the membrane-bound PKC. This activation accounts at least in part for the increased cell permeability and vascular resistance. In...

Contributors

The number in parentheses indicates the chapter to which the author contributed. Rotman Research Institute, Baycrest Centre for Care, Toronto, Ontario Department of Psychology, University of Toronto, Ontario, Canada Department Cell Biology and Neuroscience, University of South Alabama, Mobile, Section on Statistical Genetics, Department of Biostatistics and Clinical Nutrition Research Center, Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama School of...

Life Course Approach

Life course epidemiology studies the long-term effects on later health- or disease-risk of physical or social exposures during gestation, childhood, adolescence, young adulthood, and later adult life (Kuh et al., 2003). It allows the integration of biological, behavioral, clinical, psychological, and social processes that interact across a person's life (Ben-Shlomo et al., 2002). This is not a new concept in aging research. Over 50 years ago Nathan Shock wrote, ''In the broadest sense, problems...

General Characteristics and Life History Traits of the Order Chiroptera

With over 1100 species of bats worldwide, the order Chiroptera is the second most multispecied among mammals, accounting for almost one-fourth of all mammalian species. The order is divided into two suborders. The Megachiroptera is a group of just under 200 species, which includes the flying foxes and fruit bats of the Old World. The Microchiroptera with over 900 species includes all the bats of the New World and some Old World species. The two suborders differ in sensory and feeding...

Focal Ischemic Stroke Models

Focal ischemic stroke models, whether in larger mammals such as cats, dogs, or nonhuman primates, or in small mammals such as rodents, usually involve occlusion of one MCA (Lipton 1999). Focal ischemia is differentiated from global ischemia in two ways. First, even at the core of the lesion, the blood flow is almost always higher than during global ischemia so that longer insults are required to cause damage. Second, there is a significant gradation of ischemia from the core of the lesion to...

Historical Development of Animal Models of Aging

Austad The use of animal models for research parallels the rise of modern science, beginning in the late 19th century with relatively primitive experiments and increasing in sophistication as relevant science progressed. The science of aging (gerontology) was relatively late in development, and its rise both parallels and is the result of the development of new, effective animal models. Many models, including inbred strains of mice and diet-restricted mice and...

The Genetics of Chronological Aging Yeast Methuselah Genes

Using this aging paradigm, we have identified several mutations that promote life-span extension and resistance to both heat and oxidative stress. Among these is the deletion of the gene coding for the serine-threonine kinase Sch9. Lack of Sch9 promotes high-stress resistance and extends the life span up to 3-fold (Fabrizio et al., 2001). Sch9 is part of a glucose-sensing pathway, which regulates cell division, cell size, ribosomal synthesis, and the expression of stress resistance proteins...

Aging And Longevity Of Cells

Aging and longevity of differentiated cells in vitro That replicative senescence the model of aging in vitro probably is related to a chaperone deficit can be assumed from the increase in life span obtained by transfection with protein-chaperones, as well as from the attainment of cellular immortalization by heat shock procedures or transfection with RNA-chaperones (Kroll, 2004). Aging and longevity of differentiated cells in vivo The great variability in the life span of differentiated cells...

Mammalian Vs Nonmammalian Systems

A debate rages over the relevance of nonmammalian animal models to what is a uniquely human disease. Much has been learned about the basic biology of AD mechanisms from nonmammalian systems. Biochemical processes tend to follow general precepts that are comparable in simple and complex organisms. The yeast Saccharomyces cerevisiae allows the use of powerful classical and molecular genetic tools, although this organism lacks a nervous system. The roundworm Caenorhabditis elegans and the fruit...

Adipose Tissue Dysfunction

There are only scarce data on the contribution of adipose tissue dysfunction to the etiology of diabetes mellitus type 2 in relation to aging. The role of the adipose tissue is well established in relation to the increased release of free fatty acids (FFA) interfering with insulin signaling in insulin-sensitive tissues (Lewis et al., 2002). The loss of peripheral fat tissue in hereditary or acquired lipodystrophic syndromes has been associated with intramyocellular and intrahepatic fat...

The Three Longevity Phenotypes of Drosophila

One fact that has emerged from the past several decades of aging research is that aging is not simple. The work that my colleagues and I have done on Drosophila longevity bears this out. We reported that aging in our Ra strain of wild-type flies is rather complex, being characterized by at least three different extended longevity phenotypes, each of which was induced by specific stimuli and had different demographic mortality and survival profiles (Arking et al., 2002). As shown in Figure...

Pathogenesis of Diabetes Mellitus Type 2 in Relation to Aging

ALTERED INSULIN ACTION INSULIN RESISTANCE One factor clearly contributing to this age-related glucose intolerance is a decline with physiologic aging in sensitivity to the metabolic effects of insulin that is, the reduction of insulin sensitivity. This means a reduction in the activity of insulin on its target tissues such as muscle, liver, and adipose tissue. In the muscle this results in a decrease of glucose disposal. In the adipocytes this results in the inability of insulin to inhibit the...

Normal Aging Or Disease

A key issue for AD model development is whether AD is a pathological process or whether it is part of the normal sequence of aging. It is not as easy to decide this as it might seem. Sporadic AD is a condition of advanced age average onset in the general population is 80-85 years. In fact, advancing age is the single most important risk factor for AD. Some of the symptoms and many of the lesions of AD are observed in normal persons as they age, a significant number of whom never develop...

Annual Fish as Models for Aging

We believe that Nothobranchius rachovvi, a killifish, is a better vertebrate model for longevity genetics because their maximum lifespan is about ten months (Herrera and Jagadeeswaran, 2004). Nothobranchius rachovvi are tele-ostei like zebrafish and have already been used in aging studies. They have been shown to begin senescent changes at approximately four months of age. They are relatively easy to breed and are approximately 2 inches in size. The females lay approximately 20 eggs per day....

Dyslipidemia

The role of dyslipidemia in atherosclerosis has been clearly established. Both elevated LDL-cholesterol and reduced HDL-C are risk factors for atherosclerosis. This dyslipidemia has been shown to be related to bone mass and bone fragility and might represent a common underlying factor for both osteoporosis and atherosclerotic disease (Yamagushi et al., 2002). In a study of 214 postmenopausal Japanese women, plasma LDL-cholesterol levels were inversely correlated with bone mineral density at the...

Chronological Aging And Response To Stress

It has been proposed that aging in nondividing yeast cells is largely under the control of the transcription factors Msn2 and Msn4 (Fabrizio et al., 2001). Msn2 and Msn4 bind to stress response elements (STRE) contained in the promoters of many genes coding for proteins involved in adaptation to starvation and stress, such as heat shock proteins, catalase, superoxide dismutase, and glycogen and trehalose biosynthetic enzymes (Smith et al., 1998). Msn2 and Msn4 are repressed by the nutrient...

Effects of Oxidative Stress and Genotoxic Stress on Zebrafish Aging and Senescence

Several lines of evidence suggest that genotoxic or oxidative stress promote the aging process (Campisi, 2005 Finkel and Holbrook, 2000 Lombard et al., 2005). It is well known that the aging process diminishes the capability to adapt to environmental stresses. We hypothesized that genotoxic and oxidative stress leads to mutations and general declines in reproductive ability, ultimately producing the spectrum of age-related characteristics in zebrafish. Support for this idea comes from the fact...

Clinical Cohorts

A major hurdle involved in patient-oriented research in general is the effort and expense involved in recruiting a well-characterized cohort. Consequently, existing cohorts can be a fast and convenient way to test a new hypothesis as patient data, blood samples, and DNA are already collected and allow retrospective study. Health ABC Study The Health ABC Study was specifically designed to investigate connections between changes in body composition and strength, functioning, and mortality. The...

Mechanisms of Premature Aging in Diabetes

The clinical and phenotypic similarities between aging and diabetes suggest that there may be shared biochemical pathways leading to the tissue changes. Glucose is the principal metabolic fuel for many animal species. In general, with few exceptions, the plasma glucose level in various animals is maintained within a narrow range (60-140 mg dl). It is possible that the lower limit of blood glucose levels is determined by the minimum tissue requirements of metabolic fuel, and the upper limit...

Tcc Receptors And Signal Transduction

T cell functions are mediated by intracellular signaling via surface receptors such as the antigen receptor and the costimulator CD28, as discussed earlier, from the membrane (early events) through the cytoplasm (intermediate events) to the nucleus (late events). Age-related immune alterations can be partially explained by defects in receptor signal transduction. For instance, decreased calcium mobilization, MAPKinase phosphorylation, PKC0 recruitment to the membrane, NF-kB translocation to the...

Morphological and Functional Organization of the Human Retina

The retina is the most internal of the three sheets that coat the posterior wall of the eye. This sheet extends from the optical nerve to the pupil-iris border, and it can be divided into an optical part, dedicated to the function of vision, and a blind part, in conjunction with the border of the pupil. The two parts are separated by the ora serrata. The retina is structurally divided into two shares one outer and one inner. The outer share of the retina consists of the retinal pigment...

Aging And Heat Shock Proteins

A characteristic feature of aging is a progressive impairment in the ability to maintain homeostasis in the face of environmental challenges. Heat shock proteins (Hsps) consist of a family of proteins that modulate stresses to the body. Hsps are ubiquitous, highly conserved proteins that have been found in the cells of all organisms studied thus far, including plants, bacteria, yeast, flies, and vertebrates. They are part of a multigene family that has been divided into 6 subfamilies based on...

Morphological Changes Accompanying Aging In S Ratti

Autofluorescence In C. elegans, there is an increase in intestinal autofluorescence with age (Garigan et al., 2002), similar to accumulation of age-pigment (lipofuscin) seen during mammalian aging. There is a similar increase in autofluorescence with age in free-living S. ratti morphs (Gardner et al., 2004). By contrast, little such autofluorescence was seen in parasitic females, even in 11-month-old individuals (Gardner, Gems and Viney, submitted). Lipofuscin accumulation reflects organismal...

Diabetes

Diabetes is highly prevalent in older individuals, and significantly increases the risk of cardiovascular events. A meta-analysis found that the rate of depression among individuals with diabetes was twice that of individuals without diabetes (Anderson et al., 2001). In a long-term follow-up of a community cohort, the presence of depressive symptoms at baseline more than doubled the risk of developing type 2 diabetes (Palinkas et al., 2004). In addition, the presence of depression has been...

Rabbits

The rabbit has the distinction of being the first species recognized to develop diet-induced atheromatous lesions, in the landmark report by Anitschkow in 1914 (Anitschkow, 1914). New Zealand white rabbits develop lesions primarily in the aorta, and their development is associated with extraordinarily high plasma cholesterol levels (in the 1000-3000 mg dl range), which can compromise other organ systems in ways that affect the experimental utility of this model. Disease of epicardial coronary...

Rate Of Living Metabolism And Oxidative Damage

The first substantive biological theory of aging, the rate of living theory, was developed from studies on Drosophila. The early work of Loeb and Northorp (1917) demonstrated that temperature was negatively associated with lifespan in Drosophila. Raymond Pearl, a biostatis-tician who worked on population genetics, put forward this phenomenon as the rate of living theory.'' He found that the coefficient relating lifespan to ambient temperature in flies had a magnitude between two and three,...

Nonpoultry Domestic Avian Models For Aging Studies

Avian models for learning and neuroregeneration Small songbirds, including canaries, zebra finches, and sparrows, as well as small parrots and pigeons, have been used for decades in neurobiology, particularly in studies of song learning and reproductive and courtship behavior. More recently, these laboratory bird models have also become the focus of research on the potential for regeneration of certain brain regions. Male canaries normally change their songs each new breeding season as they...

Zebrafish as Model for Human Disease

Zebrafish have been used extensively in a variety of medical and scientific disciplines including cardiology, neurology, ophthalmology, and environmental toxicology. However, the majority of these studies have explored developmental aspects. Studies in mature zebrafish, and even their normal anatomy, have been largely unexplored, though they have tremendous potential as animal models for diseases that occur later in life. Their small size makes Figure 27.2. Sagittal section of zebrafish. This...