Natural Lifespan Research Articles

Molecular medicine: Prometheus unbound

Molecular Medicine can be defined as the thorough and detailed mechanistic understanding of health and disease at the cellular and molecular level, and the application of this knowledge to the design, validation, and implementation of novel strategies to promote health and prevent, diagnose, treat, and cure disease. It capitalizes on the fruits of biomedical research, which includes all biology-based scientific research that ultimately aims at understanding and improving the human condition. The observational and descriptive approach of traditional medical investigation is being gradually complemented – and will ultimately be superseded – by a science-founded approach focused on the mechanisms that underpin health and illness. The great promise for the future of medicine lies in the application of this mechanistic approach to the design of new strategies for disease treatment and prevention. The genomic transformation of medicine (functional genomics through proteomics/metabolomics to clinomics) has already begun, but its consolidation is not likely to be easy. All stages of the new paradigm face significant problems such as the inability to define clear-cut molecular disease entities and the low positive predictive values of genetic tests. Moreover, Molecular Medicine is an expensive concept all the way from the level of research and development up to the cost of the genomic testing of individual patients. However, taken together, the anticipated decreases in the number of adverse drug reactions, the number of failed drug trials, the time necessary to facilitate a drug's approval, the length of time patients are on medication, the number of medications patients must take to find an effective therapy, the toll of a disease on the body (through early detection), and the increase in the range of possible drug targets are likely to counterbalance the cost of molecular profiling and thus promote a net decrease in the cost of health care. Therefore, pharmaceutical companies have already begun to travel this one-way road at high speed with the confidence that the results will eventually offset the cost of the investment. Decision-makers in the political field also need to be informed about the need to prioritize genome science and finance genomic research. Despite the promises of the post-genomic era, there are skeptics who suggest that the prospect of the novel – molecular – paradigm in medicine is highly optimistic. Such critics argue that, although molecular biology has contributed tremendously to our understanding of the basis of health and disease, it has yet to contribute much to the day-to-day care of patients. From their viewpoint, the distance between understanding molecular circuitries and developing clinically useful interventions is vast and may never be bridged. Being actively involved in informing and educating both the end users – physicians and patients – and the lay public about the benefits and promises of Molecular Medicine, I cannot share this frustrating pessimism. I believe that since mankind has consciously decided to embark on this bold and ambitious journey to decipher the secrets of life, sooner or later the riddles of health and disease will be solved. Insights from systems biology can have a crucial role to this end. Most cellular functions are carried out by a complex network of genes, proteins, and metabolites that interact through biochemical and physical interactions (human interactome). Discovering systematic correlations between cellular networks, environmental/lifestyle factors and disease patterns may help unveil hitherto unknown disease pathways. The characterization of molecular events involved in the onset of a pathology will not only enable us to identify new putative pharmacological targets, and hence resolve complex diseases, but also to predict an individual's health and extend the human body's natural lifespan by preventing diseases (personalized therapy). Whether this shift in the practice of medicine will translate into global relief of human suffering will probably depend on society as a whole and not only on the fruits of biomedical research. However, with sound prioritization of goals and rational allocation of resources, it should be only a matter of time until the novel paradigm of Molecular Medicine is broadly established as the ultimate standard of care. Perhaps the most challenging task in the post-genomic era will be to translate the advancements of biomedical science to an improvement of the quality of life across all members of society, which will increasingly depend on a responsible and conscious loyalty to the moral principles of the “art” of medicine.

Rationing Health Care at the End of Life

This paper discusses the main arguments for and against rationing health care at the end of life in the United States. It was published in 2010 in connection with a National Debate and Discussion Series by the University of Virginia’s Miller Center on End-of-Life Care. The perspectives discussed in the paper against rationing health care at the end of life include the following: (a) there is nothing wrong with spending large amounts of money on health care, including at the end of life; (b) cost-savings at the end of life can be achieved by “rational care” rather than by rationing care; and (c) targeting end-of-life care for rationing would be unethical and result in only small cost savings. The primary argument in favor of rationing at the end of life is that rationing health care in some way is unavoidable and inevitable and that rationing at the end of life is far preferable to our current system of rationing. “End of life” may mean the end of a particular individual’s life, no matter the person’s age or cause of dying. Under a second meaning, “end of life” refers to old age, or the end of a natural life span. Arguments in favor of rationing at the end of life in both senses is explored.

The natural lifespan of a safety policy: violations and system migration in anaesthesia

BackgroundSafety rules continue growing rapidly, as if constraining human behaviour was the unique avenue for reaching ultimate safety. Safety rules are essential for a safe system, but their multiplication can...

CONCERNING THE HEALTH EFFECTS OF INTERNALLY DEPOSITED RADIONUCLIDES

The ionizing radiation dose-response relationships for internally deposited radionuclides are examined using data from humans involving Ra and laboratory animal studies involving alpha-emitters Ra, Ra, Ra, Th, Pu, Pu, and Am and beta-emitters Y, Sr, Y, and Ce. Intake routes included ingestion, inhalation, and injection. The lifetime effects are best described by three-dimensional average-dose-rate/time/response surfaces that compete with other causes of death during an individual's lifetime. Using maximum likelihood survival regression methods, the characteristic logarithmic slope for cancer induction was found to be about negative one-third for alpha-emitters or about negative two-thirds for beta-emitters. At the higher average dose-rates the principal deleterious effects were those associated with radiation-induced injury while at intermediate average dose-rates radiation-induced cancer predominates. The relative biological effectiveness for cancer induction of high linear energy transfer alpha radiation with respect to low linear energy transfer beta radiation is a strong function of dose-rate. As average dose-rate decreases, the effectiveness of the beta irradiation drops off more rapidly than that of the alpha irradiation. The cumulative dose yielding a specific level of induced cancer risk is less at lower dose-rates than at higher dose-rates showing an apparent inverse dose-rate effect (up to a factor of about 10 for high linear energy transfer alpha radiation and a factor of about 2 for low linear energy transfer beta radiation). The cumulative radiation dose is neither an accurate nor an appropriate measure of cancer risk associated with protracted ionizing radiation exposure. Cancer risk associated with protracted ionizing radiation exposure is a non-linear function of lifetime average dose-rate to the affected tissues. At low average dose-rates the long latency time required for radiation-induced cancer may exceed the natural lifespan. This long latency results in a lifespan virtual threshold (cancer risk p < 0.001) for each internally deposited radionuclide. For young adult beagles, bone sarcoma induction from alpha-emitting radionuclides was unlikely for cumulative doses below about 1 Gy (20 Sv) delivered specifically to the sensitive tissues at bone surfaces in a manner associated with radionuclide relative potency from highest for Th, Pu, and Pu to lowest for Ra. Bone sarcoma induction from ingested Sr was unlikely for cumulative beta radiation doses below about 20 Gy (20 Sv), but beta irradiation of tissues adjacent to bone also induced leukemia and soft tissue carcinomas above 10 Gy (10 Sv). Inhaled radionuclides tended to be most potent in producing lung carcinoma when the radiation dose was most uniformly distributed in the lung. In young adult beagles lung carcinoma from inhaled alpha-emitting Pu in the dispersible nitrate form was unlikely for cumulative doses below about 0.5 Gy (10 Sv) and below higher cumulative doses for other forms of Pu and Pu depending on relative potency. Lung carcinoma from inhaled beta-emitting Y in relatively insoluble fused aluminosilicate particles was unlikely for cumulative doses below about 5 Gy (5 Sv) and below higher doses for inhaled particles with Y, Ce, or Sr in order of decreasing potency.

Kinesin-1/Hsc70-dependent mechanism of slow axonal transport and its relation to fast axonal transport

Cytoplasmic protein transport in axons ('slow axonal transport') is essential for neuronal homeostasis, and involves Kinesin-1, the same motor for membranous organelle transport ('fast axonal transport'). However, both molecular mechanisms of slow axonal transport and difference in usage of Kinesin-1 between slow and fast axonal transport have been elusive. Here, we show that slow axonal transport depends on the interaction between the DnaJ-like domain of the kinesin light chain in the Kinesin-1 motor complex and Hsc70, scaffolding between cytoplasmic proteins and Kinesin-1. The domain is within the tetratricopeptide repeat, which can bind to membranous organelles, and competitive perturbation of the domain in squid giant axons disrupted cytoplasmic protein transport and reinforced membranous organelle transport, indicating that this domain might have a function as a switchover system between slow and fast transport by Hsc70. Transgenic mice overexpressing a dominant-negative form of the domain showed delayed slow transport, accelerated fast transport and optic axonopathy. These findings provide a basis for the regulatory mechanism of intracellular transport and its intriguing implication in neuronal dysfunction.

Compound Deficiency of Nrf2 and Selenoproteins in Hematopoietic Cells Leads to Severe Defects in Erythroid and Lymphoid Lineage Development.

Abstract 1993Poster Board I-1015Precise regulation of reactive oxygen species (ROS) level is essential for normal cellular homeostasis. Defect of ROS scavenging system results in excess accumulation of ROS in cells, leading to the cellular aging and senescence. Nrf2 (NF-E2-related factor 2) is a basic leucine zipper-type transcription factor, which regulates expression of a set of genes related to the ROS scavenging and detoxification. While accumulating lines of evidence support the significance of Nrf2 for the cellular protection in many types of cells, Nrf2-deficient mice live out their natural life span under the homeostatic condition, and show no significant hematological abnormality except for anemia with aging. We previously found that the Nrf2 activity rose in the macrophages and liver cells derived from conditional knockout (CKO) mice of the selenocystein tRNA (Trsp) gene. The Trsp gene is essential for production of selenoproteins, including glutathione peroxidase and thioredoxin reductase. Thus, there are two prevalent ROS scavenging systems based on different molecular mechanisms; Nrf2 and selenoproteins seemingly act compensatory and cooperatively for maintenance of hematopoietic homeostasis. To explore the roles Nrf2 and selenoproteins play in hematopoietic cells, we conducted conditional knockout of the Trsp gene by crossing Trsp-floxed mice with the interferon-inducible Mx1-Cre transgenic mice in combination with Nrf2 gene knockout (KO) in germline. The Trsp-CKO mice in the background of Nrf2 wild type (Trsp single KO mice) showed thymic atrophy with massive reduction of CD4/CD8 double-positive cells in thymus. This T-lymphocytic phenotype was not changed in the Trsp-CKO mice under the circumstance of Nrf2-null condition (Trsp:Nrf2 double KO mice), suggesting that selenoproteins were prerequisite for the T-cell development. The Trsp single KO mice suffered from mild anemia with increased number of erythroid progenitors in bone marrow and spleen, and importantly this erythroid phenotype was dramatically exacerbated in the Trsp:Nrf2 double KO mice. A large number of poikilocytes and teardrop-shaped cells were observed in the blood smear of the Trsp:Nrf2 double KO mice, whereas these deformed red blood cells were vaguely found in the Trsp single KO mice. Intracellular ROS level was significantly elevated in erythroid progenitors recovered from the Trsp:Nrf2 double KO mice, although that of the Trsp single KO mice were maintained within normal level, indicating that Nrf2 compensates for the defect of ROS scavenging function caused by the loss of selenoproteins in erythroid cells. These results thus demonstrate for the first time that the ROS scavenging conducted by Nrf2 and selenoproteins is essential for the homeostatic maintenance in erythroid and lymphoid cells in a lineage-specific manner. Disclosures:No relevant conflicts of interest to declare.

Polymorphism at the avpr1a locus in male prairie voles correlated with genetic but not social monogamy in field populations

Integrative studies of genetics, neurobiology and behaviour indicate that polymorphism in specific genes contributes to variation observed in some complex social behaviours. The neuropeptide arginine vasopressin plays an important role in the regulation of a variety of social behaviours, including social attachment of males to females, through its action on the vasopressin 1a receptor (V1aR). In socially monogamous prairie voles (Microtus ochrogaster), polymorphism in the length of microsatellite DNA within the regulatory region of the gene (avpr1a) encoding the V1aR predicts differences among males in neural expression of V1aRs and partner preference under laboratory conditions. However, understanding the extent to which V1aR mediates variation in prairie vole social and reproductive behaviour observed in nature requires investigating the consequences of avpr1a polymorphism and environmental influences under ecologically relevant conditions. We examined the relationship between avpr1a length polymorphism and monogamy among male prairie voles living in 0.1 ha enclosures during a time similar to their natural lifespan. We found no evidence that avpr1a genotype of males predicts variation in social monogamy measured in the field but some indices of social monogamy were affected by population density. Parentage data indicated that a male's avpr1a genotype significantly influenced the number of females with which he sired offspring and the total number of offspring sired. Total brain concentrations of V1aR mRNA were not associated with either male behaviour or avpr1a genotype. These data show that melding ecological field studies with neurogenetics can substantially augment our understanding of the effects of genes and environment on social behaviours.

Extending platelet storage: safety and quality considerations

Although the natural life span of platelets is 7–10 days,platelet transfusion to stop or prevent bleeding is currentlyrestricted by storage limits of 4–7 days, depending on theregulatory authority and whether bacterial risk mitigationis performed. Not only the risk of bacterial growth, but alsoplatelet function and storage-dependent deterioration,referred to as platelet storage lesion (PSL) should be consid-ered. The extent of PSL correlates with reduced platelet invivorecovery and survival as well as haemostatic activityafter transfusion [1].

Building a new bridge between metabolism, free radicals and longevity

Building a new bridge between metabolism, free radicals and longevity

Sex differences in nutrient‐dependent reproductive ageing

Evolutionary theories of aging predict that fitness-related traits, including reproductive performance, will senesce because the strength of selection declines with age. Sexual selection theory predicts, however, that male reproductive performance (especially sexual advertisement) will increase with age. In both bodies of theory, diet should mediate age-dependent changes in reproductive performance. In this study, we show that the sexes exhibit dramatic, qualitative differences in age-dependent reproductive performance trajectories and patterns of reproductive ageing in the cricket Teleogryllus commodus. In females, fecundity peaked early in adulthood and then declined. In contrast, male sexual advertisement increased across the natural lifespan and only declined well beyond the maximum field lifespan. These sex differences were robust to deviations from sex-specific dietary requirements. Our results demonstrate that sexual selection can be at least as important as sex-dependent mortality in shaping the signal of reproductive ageing.

SNP'ing for longevity

SNP'ing for longevity

Effect of in vitro maturation of mouse oocytes on the health and lifespan of adult offspring

In vitro maturation of oocytes can, in some circumstances, provide an alternative approach to gonadotrophin-induced maturation in clinical settings. However, the consequences of these protocols on the long-term health of offspring are unknown. Here, the long-term health status and lifespans of offspring produced by in vitro maturation of mouse oocytes was compared with that of oocytes induced to mature in vivo using gonadotrophin treatment. Mouse oocytes were matured in vitro using both an established optimized system and in the absence of amino acids to produce a suboptimal condition for maturation. Oocytes induced to mature in vivo with gonadotrophins constituted the control group. All metaphase II oocytes were fertilized in vitro and transferred at the 2-cell stage to the oviducts of pseudo-pregnant foster mothers for development to term. Offspring were subjected to a wide variety of physiological and behavioral tests for the first year of life and natural lifespan determined. There was no difference among the groups in lifespan or in most of the physiological and behavioral analyses. However, the pulse rate and cardiac output were slightly, but significantly, reduced in the optimized in vitro matured group compared with the in vivo matured group (P = 0.0119 and P = 0.0197, respectively). Surprisingly, these decreases were largely abrogated in the in vitro group matured without amino acids. Evidence presented here using a mouse model suggests that the in vitro maturation of oocytes has minimal effects on the long-term health of offspring. However, a finding of slight reductions in pulse rate and cardiac output may focus future clinical attention.

The Perception of Good Death Among Human Service Students in South Korea: A Q-Methodological Approach

The purpose of this study was to examine the subjective opinions of Korean college students about good death. Q methodology was used to analyze 34 Q-statements from 37 respondents who majored in social work, nursing, or education at a university in South Korea. With the use of a PC-QUANL software package, 4 types of perceptions about good death were identified. They are a resolute acceptance type; a reasonable, natural lifespan type; a relational, sentimental type; and an altruistic, satisfied type. Results of this study indicate that approaches to death education need to be differentiated to take into account this typology and the characteristics of the students that fall into each category.

Genomic Instability Is Associated with Natural Life Span Variation in Saccharomyces cerevisiae

Increasing genomic instability is associated with aging in eukaryotes, but the connection between genomic instability and natural variation in life span is unknown. We have quantified chronological life span and loss-of-heterozygosity (LOH) in 11 natural isolates of Saccharomyces cerevisiae. We show that genomic instability increases and mitotic asymmetry breaks down during chronological aging. The age-dependent increase of genomic instability generally lags behind the drop of viability and this delay accounts for ∼50% of the observed natural variation of replicative life span in these yeast isolates. We conclude that the abilities of yeast strains to tolerate genomic instability co-vary with their replicative life spans. To the best of our knowledge, this is the first quantitative evidence that demonstrates a link between genomic instability and natural variation in life span.

A unique life history among tetrapods: An annual chameleon living mostly as an egg

The approximately 28,300 species of tetrapods (four-limbed vertebrates) almost exclusively have perennial life spans. Here, we report the discovery of a remarkable annual tetrapod from the arid southwest of Madagascar: the chameleon Furcifer labordi, with a posthatching life span of just 4-5 months. At the start of the active season (November), an age cohort of hatchlings emerges; larger juveniles or adults are not present. These hatchlings grow rapidly, reach sexual maturity in less than 2 months, and reproduce in January-February. After reproduction, senescence appears, and the active season concludes with population-wide adult death. Consequently, during the dry season, the entire population is represented by developing eggs that incubate for 8-9 months before synchronously hatching at the onset of the following rainy season. Remarkably, this chameleon spends more of its short annual life cycle inside the egg than outside of it. Our review of tetrapod longevity (>1,700 species) finds no others with such a short life span. These findings suggest that the notorious rapid death of chameleons in captivity may, for some species, actually represent the natural adult life span. Consequently, a new appraisal may be warranted concerning the viability of chameleon breeding programs, which could have special significance for species of conservation concern. Additionally, because F. labordi is closely related to other perennial species, this chameleon group may prove also to be especially well suited for comparative studies that focus on life history evolution and the ecological, genetic, and/or hormonal determinants of aging, longevity, and senescence.

Rosalià Abreu and the Apes of Havana

Rosalia Abreu (1862–1930) was a wealthy amateur collector and keeper of primates, including apes. She was the first person to keep orangutans and chimpanzees alive in captivity for their natural lifespans, and the first to breed chimpanzees. Although not a scientist, she made her animals available for scientific study, and it was on her animals that the first published observations of chimpanzee mating, birth, and development were made. The system of husbandry that she designed for apes, with an emphasis on spacious cages, vegetarian diet, cleanliness, and social contact (preferably conspecific, but heterospecific where conspecifics were not available), were groundbreaking in their time. Through her extensive correspondence, her methods of husbandry spread and formed the basis of captive ape practices around the world. Though much of Abreu’s work was forward-looking, other aspects, such as her belief that chimpanzees were monogamous and had psychic abilities, strike modern readers as eccentric. Nonetheless primatologists today may be helped to see the cultural assumptions that underlie today’s research by noting those that guided research in the past.

Loss of cardiac tetralinoleoyl cardiolipin in human and experimental heart failure

The mitochondrial phospholipid cardiolipin is required for optimal mitochondrial respiration. In this study, cardiolipin molecular species and cytochrome oxidase (COx) activity were studied in interfibrillar (IF) and subsarcolemmal (SSL) cardiac mitochondria from Spontaneously Hypertensive Heart Failure (SHHF) and Sprague-Dawley (SD) rats throughout their natural life span. Fisher Brown Norway (FBN) and young aortic-constricted SHHF rats were also studied to investigate cardiolipin alterations in aging versus pathology. Additionally, cardiolipin was analyzed in human hearts explanted from patients with dilated cardiomyopathy. A loss of tetralinoleoyl cardiolipin (L(4)CL), the predominant species in the healthy mammalian heart, occurred during the natural or accelerated development of heart failure in SHHF rats and humans. L(4)CL decreases correlated with reduced COx activity (no decrease in protein levels) in SHHF cardiac mitochondria, but with no change in citrate synthase (a matrix enzyme) activity. The fraction of cardiac cardiolipin containing L(4)CL became much lower with age in SHHF than in SD or FBN mitochondria. In summary, a progressive loss of cardiac L(4)CL, possibly attributable to decreased remodeling, occurs in response to chronic cardiac overload, but not aging alone, in both IF and SSL mitochondria. This may contribute to mitochondrial respiratory dysfunction during the pathogenesis of heart failure.

Reply

We thank Drs Gonzalez-García and Castells for their commentary on our paper (Cancer cell, 2006;9:199–207). We have little to add, but we appreciate the opportunity we have been given to highlight the interesting difference between the genetic and epigenetic alterations observed in gastrointestinal cancer. Although somatic mutations must be present in normal tissues, they are not reproducibly found by the techniques used for mutational analyses. This means that mutations must be very rare. If they are nonfunctional, they remain undetectable, confined to a few normal cells in the intestinal epithelium. If they contribute to neoplastic or malignant transformation (for instance, APC, K-ras), then, the normal tissue cells where they occur do not stay normal for long. By contrast, epigenetic alterations (both DNA hypermethylation and hypomethylation) are frequently detected in normal tissues adjacent to tumors. This means that they must occur with relatively high frequency, thereby allowing for clonal expansion of normal cells harboring these alterations in their natural life spans. The intestinal epithelium is a tissue with very high cell turnover, continuously replenished by self-renewing stem cells. During aging, the destruction of stem cells in the intestinal crypts entails a necessary expansion of larger patches of normal tissue derived from the same single stem cells. Detection of epigenetic alterations accumulating with aging is thus possible, especially when sensitive techniques are used. Whether these epigenetic alterations occur in the normal tissues of all people or only cancer patients remains to be determined. In this context, our unpublished results show the accumulation of global demethylation in normal gastric tissues adjacent to gastric cancers, and in normal tissues of cancer-risk chronic gastritis patients, compared with the normal tissues from cancer-free individuals. We also wish to correct Drs González-García and Castells in their citation of our past work “…Ionov et al (Nature 1993;363:558–561) showed that some tumors accumulated hundreds or thousands of somatic mutations in microsatellite sequences. …” We reported the existence of hundreds of thousands of somatic, clonal mutations in these tumors. It may be a typographical error, but does make a big difference. Finally, our only disagreement with González-García and Castells is with the last sentence of their commentary “More studies are needed to clarify this controversial [CIMP] issue.” We disagree that the CIMP issue is controversial. Although more DNA methylation experiments are necessary regarding many important issues (see above), we do not think there are more needed regarding the CIMP issue. The CIMP story is a fascinating example of how untenable hypotheses can be perpetuated in the absence of supporting evidence. It is fascinating, because the concept is defended by converted followers of the hypothesis despite being in contradiction with each other (Nat Genet 2006;38:787–793; Gastroenterology 2007;132:127–138), even when the original proponents hauled down the sails (“The controversy over CIMP will almost certainly one day be considered a storm in a tea pot,” Gastroenterology 2005;129:1121–1124). A methylator phenotype implies the existence of underlying methylator genes. Eight years after the original proposal of the CIMP hypothesis (Proc Natl Acad Sci U S A 1999;96:8681–8686), we are still waiting to know where and what the methylator genes are. New Insights into a Controversial Topic: The Methylation–Cancer ConnectionGastroenterologyVol. 132Issue 5PreviewSuzuki K, Suzuki I, Leodolter A, Horiuchi S, Yamashita K, Perucho M (Burnham Institute for Medical Research, Cancer Genetics and Epigenetics Research Program, La Jolla, CA). Global DNA demethylation in gastrointestinal cancer is age dependent and precedes genomic damage. Cancer Cell 2006;9:199–207. Full-Text PDF

A New Antireflux Technique: Mucosal Flap Barrier

Introduction: In this study, our aim was to evaluate the effectiveness of the mucosal flap barrier (MFB) upon the incompetent ureteral orifice of an experimentally produced rabbit reflux model. The rabbit reflux model was done in the first stage of the study. This method is a new and original procedure which is different from Bischoff’s and Witherington’s osteoplasty techniques. Materials and Methods: We performed the mucosal flap procedure in eight 2–2.5 kg male New Zealand rabbits with experimentally produced refluxing ureters. The first stage of our study was to create refluxing ureters. Due to the upward and inward ‘J’ fishhook course of the intravesical ureter of rabbits, we performed two deep 12- and 4-o’clock incisions by suturing the edges of the intravesical ureter apart with catgut sutures. Additionally, to stop the tilting action of the trigonum during micturition, we performed two parallel incisions between the ureteral meatus. These parallel incisions were the authors’ modifications for the rabbit reflux model and which gives long-lasting reflux for the rabbit. We checked the reflux at the end of the 3rd month and performed our new MFB antireflux procedure. This mucosal flap made a cover on the incompetent ureteral orifice. This technique is completely different from the osteoplasty techniques described by Bischoff and Witherington. Results: Four months after the MFB application, we performed intravenous urography, cystometry and cinefluorography. There was no obstruction or reflux. Two rabbits were sacrificed at the 4th month. Both flaps were fully intact without any fixation at the medial side causing obstruction. At present, 3 rabbits are still alive. We did cinefluorography and cystometry at the 15th month and there was no obstruction or reflux. We are trying to keep them alive till the end of their natural lifespan. Conclusions: During the formation of the rabbit reflux model, we observed that spontaneous reflux even at high intravesical pressures did not have high percentages as previously mentioned in the literature. But it is possible and enough to produce an experimental reflux model by using meatotomy and interureteric incisions. Moreover, in rabbits with vesicoureteral regurgitation produced by ureteral meatotomy and interureteral incisions, reflux can be eliminated the MFB procedure. This method is an easy procedure for small bladders or dilated ureters after any kind of open reimplantation applications and it could be used by pneumovesical applications in the future.

High-Resolution Mapping of Quantitative Trait Loci Affecting Increased Life Span in Drosophila melanogaster

Limited life span and senescence are near-universal characteristics of eukaryotic organisms, controlled by many interacting quantitative trait loci (QTL) with individually small effects, whose expression is sensitive to the environment. Analyses of mutations in model organisms have shown that genes affecting stress resistance and metabolism affect life span across diverse taxa. However, there is considerable segregating variation for life span in nature, and relatively little is known about the genetic basis of this variation. Replicated lines of Drosophila that have evolved increased longevity as a correlated response to selection for postponed senescence are valuable resources for identifying QTL affecting naturally occurring variation in life span. Here, we used deficiency complementation mapping to identify at least 11 QTL on chromosome 3 that affect variation in life span between five old (O) lines selected for postponed senescence and their five base (B) population control lines. Most QTL were sex specific, and all but one affected multiple O lines. The latter observation is consistent with alleles at intermediate frequency in the base population contributing to the response to selection for postponed senescence. The QTL were mapped with high resolution and contained from 12 to 170 positional candidate genes.