Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 39
Filter
2.
Ann Oncol ; 29(2): 361-369, 2018 02 01.
Article in English | MEDLINE | ID: mdl-29077785

ABSTRACT

Background: Cisplatin-based combination chemotherapy is the standard treatment of advanced urinary tract cancer (aUTC), but 50% of patients are ineligible for cisplatin according to recently published criteria. We used a multinational database to study patterns of chemotherapy utilization in patients with aUTC and determine their impact on survival. Patients and methods: This was a retrospective study of patients with: UTC (bladder, renal pelvis, ureter or urethra); advanced disease (stages T4b and/or N+ and/or M+); urothelial, squamous or adenocarcinoma histology. Primary objective was overall survival (OS). Eligibility-for-cisplatin was defined by Eastern Cooperative Oncology Group performance status ≤ 1, creatinine clearance ≥ 60 ml/min, no hearing loss, no neuropathy and no heart failure. Cox regression multivariate analyses were used to establish independent associations of cisplatin versus noncisplatin-based chemotherapy on OS. Results: 1794 patients treated between 2000 and 2013 at 29 centers were analyzed. Median follow-up was 29.1 months. About 1333 patients (74%) received first-line chemotherapy: the use of first-line chemotherapy was associated with longer OS: [hazard ratio (HR): 1.91, 95% confidence interval (CI): 1.67-2.20]. Type of first-line chemotherapy received was: cisplatin-based 669 (50%), carboplatin-based 399 (30%) and other 265 (20%). Cisplatin use was an independent favorable prognostic factor (HR: 1.54, 95% CI: 1.35-1.77). This benefit was independent of baseline characteristics or comorbidities but was associated with eligibility-for-cisplatin: eligible patients treated with cisplatin lived longer than those who were not (HR: 1.74, 95% CI: 1.36-2.21), while such benefit was not observed among ineligible patients. About 26% of patients who did not receive cisplatin were eligible for this agent. Median OS of ineligible patients was poor irrespective of the chemotherapy used. Conclusions: The importance of applying published criteria of eligibility-for-cisplatin was confirmed in a multinational, real-world setting in aUTC. The reasons for deviations from these criteria set targets to improve adherence. Effective therapies for cisplatin-ineligible patients are needed.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Urologic Neoplasms/drug therapy , Cisplatin/administration & dosage , Humans , Retrospective Studies , Treatment Outcome , Urologic Neoplasms/mortality
3.
Kidney Cancer ; 1(1): 31-40, 2017 Jul 26.
Article in English | MEDLINE | ID: mdl-30334002

ABSTRACT

In 2017, there is no adjuvant systemic therapy proven to increase overall survival in non-metastatic renal cell carcinoma (RCC). The anti-PD-1 antibody nivolumab improves overall survival in metastatic treatment refractory RCC and is generally tolerable. Mouse solid tumor models have revealed a benefit with a short course of neoadjuvant PD-1 blockade compared to adjuvant therapy. Two ongoing phase 2 studies of perioperative nivolumab in RCC patients have shown preliminary feasibility and safety with no surgical delays or complications. The recently opened PROSPER RCC trial (A Phase 3 RandOmized Study Comparing PERioperative Nivolumab vs. Observation in Patients with Localized Renal Cell Carcinoma Undergoing Nephrectomy; EA8143) will examine if the addition of perioperative nivolumab to radical or partial nephrectomy can improve clinical outcomes in patients with high risk localized and locally advanced RCC. With the goal of increasing cure and recurrence-free survival (RFS) rates in non-metastatic RCC, we are executing a three-pronged, multidisciplinary approach of presurgical priming with nivolumab followed by resection and adjuvant PD-1 blockade. We plan to enroll 766 patients with clinical stage ≥T2 or node positive M0 RCC of any histology in this global, randomized, unblinded, phase 3 National Clinical Trials Network study. The investigational arm will receive two doses of nivolumab 240 mg IV prior to surgery followed by adjuvant nivolumab for 9 months. The control arm will undergo the current standard of care: surgical resection followed by observation. Patients are stratified by clinical T stage, node positivity, and histology. The trial is powered to detect a 14.4% absolute benefit in the primary endpoint of RFS from the ASSURE historical control of 55.8% to 70.2% at 5 years (HR = 0.70). The study is also powered to detect a significant overall survival benefit (HR 0.67). Key safety, feasibility, and quality of life endpoints are incorporated. PROSPER RCC exemplifies team science with a host of planned correlative work to investigate the impact of the baseline immune milieu and changes after neoadjuvant priming on clinical outcomes.

4.
Genome Res ; 26(6): 787-98, 2016 06.
Article in English | MEDLINE | ID: mdl-27197209

ABSTRACT

Gene duplications play a key role in the emergence of novel traits and in adaptation. But despite their centrality to evolutionary processes, it is still largely unknown how new gene duplicates are initially fixed within populations and later maintained in genomes. Long-standing debates on the evolution of gene duplications could be settled by determining the relative importance of genetic drift vs. positive selection in the fixation of new gene duplicates. Using the Drosophila Global Diversity Lines (GDL), we have combined genome-wide SNP polymorphism data with a novel set of copy number variant calls and gene expression profiles to characterize the polymorphic phase of new genes. We found that approximately half of the roughly 500 new complete gene duplications segregating in the GDL lead to significant increases in the expression levels of the duplicated genes and that these duplications are more likely to be found at lower frequencies, suggesting a negative impact on fitness. However, we also found that six of the nine gene duplications that are fixed or close to fixation in at least one of the five populations in our study show signs of being under positive selection, and that these duplications are likely beneficial because of dosage effects, with a possible role for additional mutations in two duplications. Our work suggests that in Drosophila, theoretical models that posit that gene duplications are immediately beneficial and fixed by positive selection are most relevant to explain the long-term evolution of gene duplications in this species.


Subject(s)
Drosophila melanogaster/genetics , Transcriptome , Animals , DNA Copy Number Variations , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Evolution, Molecular , Gene Duplication , Gene Frequency , Male , Selection, Genetic
5.
Br J Cancer ; 110(8): 1917-22, 2014 Apr 15.
Article in English | MEDLINE | ID: mdl-24691425

ABSTRACT

BACKGROUND: Limited data exist on outcomes for metastatic renal cell carcinoma (mRCC) patients treated with multiple lines of therapy. Benchmarks for survival are required for patient counselling and clinical trial design. METHODS: Outcomes of mRCC patients from the International mRCC Database Consortium database treated with 1, 2, or 3+ lines of targeted therapy (TT) were compared by proportional hazards regression. Overall survival (OS) and progression-free survival (PFS) were calculated using different population inclusion criteria. RESULTS: In total, 2705 patients were treated with TT of which 57% received only first-line TT, 27% received two lines of TT, and 16% received 3+ lines of TT. Overall survival of patients who received 1, 2, or 3+ lines of TT were 14.9, 21.0, and 39.2 months, respectively, from first-line TT (P<0.0001). On multivariable analysis, 2 lines and 3+ lines of therapy were each associated with better OS (HR=0.738 and 0.626, P<0.0001). Survival outcomes for the subgroups were as follows: for all patients, OS 20.9 months and PFS 7.2 months; for those similar to eligible patients in the first-line ADAPT trial, OS 14.7 months and PFS 5.6 months; for those similar to patients in first-line TIVO-1 trial, OS 24.8 months and PFS 8.2 months; for those similar to patients in second-line INTORSECT trial, OS 13.0 months and PFS 3.9 months; and for those similar to patients in the third-line GOLD trial, OS 18.0 months and PFS 4.4 months. CONCLUSIONS: Patients who are able to receive more lines of TT live longer. Survival benchmarks provide context and perspective when interpreting and designing clinical trials.


Subject(s)
Carcinoma, Renal Cell/drug therapy , Molecular Targeted Therapy , TOR Serine-Threonine Kinases/antagonists & inhibitors , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Aged , Aged, 80 and over , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Carcinoma, Renal Cell/pathology , Clinical Trials as Topic , Disease-Free Survival , Female , Humans , Male , Middle Aged , Neoplasm Metastasis , Proportional Hazards Models , Survival Analysis , Treatment Outcome
6.
Br J Cancer ; 109(10): 2548-53, 2013 Nov 12.
Article in English | MEDLINE | ID: mdl-24129239

ABSTRACT

BACKGROUND: A phase III trial demonstrated an overall survival advantage with the addition of vinflunine to best supportive care (BSC) in platinum-refractory advanced urothelial cancer. We subsequently examined the impact of an additional 2 years of survival follow-up and evaluated the influence of first-line platinum therapy on survival. METHODS: The 357 eligible patients from the phase III study were categorised into two cohorts depending on prior cisplatin treatment: cisplatin or non-cisplatin. Survival was calculated using the Kaplan-Meier method. RESULTS: The majority had received prior cisplatin (70.3%). Survival was higher in the cisplatin group (HR: 0.76; CI 95% 0.58-0.99; P=0.04) irrespective of treatment arm. Multivariate analysis including known prognostic factors (liver involvement, haemoglobin, performance status) and prior platinum administration did not show an independent effect of cisplatin. Vinflunine reduced the risk of death by 24% in the cisplatin-group (HR: 0.76; CI 95% 0.58-0.99; P=0.04) and by 35% in non-cisplatin patients (HR: 0.65; CI 95% 0.41-1.04; P=0.07). INTERPRETATION: Differences in prognostic factors between patients who can receive prior cisplatin and those who cannot may explain the survival differences in patients who undergo second line therapy. Prior cisplatin administration did not diminish the subsequent benefit of vinflunine over BSC.


Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Transitional Cell/drug therapy , Carcinoma, Transitional Cell/mortality , Cisplatin/therapeutic use , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/mortality , Vinblastine/analogs & derivatives , Adult , Aged , Aged, 80 and over , Carcinoma, Transitional Cell/pathology , Chemotherapy, Adjuvant , Cohort Studies , Drug Resistance, Neoplasm , Female , Humans , Male , Middle Aged , Neoplasm Metastasis , Survival Analysis , Urinary Bladder Neoplasms/pathology , Urothelium/pathology , Vinblastine/therapeutic use
7.
Heredity (Edinb) ; 109(4): 226-34, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22760232

ABSTRACT

One of the persistent problems in biology is understanding how genetic variation contributes to phenotypic variation. Associations at many levels have been reported, and yet causal inference has remained elusive. We propose to rely on the knowledge of causal relationships established by molecular biology approaches. The existing molecular knowledge forms a firm backbone upon which hypotheses connecting genetic variation, transcriptional variation and phenotypic variation can be built. The sex determination pathway is a well-established molecular network, with the Yolk protein 1-3 (Yp) genes as the most downstream target. Our analyses reveal that genetic variation in expression for genes known to be upstream in the pathway explains variation in downstream targets. Relationships differ between the two sexes, and each Yp has a distinct transcriptional pattern. Yp expression is significantly negatively correlated with longevity, an important life history trait, for both males and females.


Subject(s)
Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Genetic Variation , Longevity/genetics , Models, Molecular , Systems Biology , Animals , Cluster Analysis , Dosage Compensation, Genetic , Drosophila melanogaster/physiology , Egg Proteins/genetics , Female , Gene Regulatory Networks , Male , Sex Determination Processes , Transcriptome , Vitellogenins/genetics
8.
Minerva Pediatr ; 64(2): 159-69, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22495190

ABSTRACT

Chronic kidney disease (CKD) is a continuum of progressive reduction in kidney function lasting for more than three months, due to either structural and/or functional renal abnormalities that may lead to irreversible kidney damage. The term "renal supportive therapy" (RST) generally characterizes the spectrum of dialysis therapies available to support existing renal function in patients with CKD during progression to end-stage renal disease (ESRD) and/or renal transplantation. Chronic RST modalities include conventional hemodialysis, peritoneal dialysis and home hemodialysis therapies. The modality chosen to deliver RST in the pediatric patient is often guided by a variety of factors including institutional resources, local expertise, patient characteristics, treatment goals, and physician preference. Chronic RST in a pediatric population requires the flexible utilization of multiple delivery modalities for effective care across infancy into adulthood and is not typically initiated until GFR declines to between 15-30 mL/min per 1.73 m2, although thresholds for initiation of RST will vary between patients. This review will provide an overview of current approaches to management and technical approaches to pediatric patients requiring chronic hemodialysis.


Subject(s)
Kidney Failure, Chronic/therapy , Renal Dialysis , Child , Hemodialysis, Home/statistics & numerical data , Humans , Interdisciplinary Communication , Peritoneal Dialysis/statistics & numerical data , Quality of Life , Renal Dialysis/statistics & numerical data , Survival Analysis , Time Factors , Treatment Outcome
9.
J Evol Biol ; 25(2): 378-87, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22151916

ABSTRACT

Laboratory selection for resistance to starvation has been conducted under relatively controlled conditions to investigate direct and correlated responses to artificial selection. With regard to starvation resistance, there are three physiological routes by which the trait can evolve: resource accumulation, energy conservation and starvation tolerance. A majority of energetic compounds and macromolecules including triglycerides, trehalose and other sugars, and soluble protein increased in abundance as a result of selection. Movement was additionally investigated with selected males moving less than control males and selected females exhibiting a similar response to selection. Results obtained from this study supported two of the possible evolutionary mechanisms for adaptation to starvation: energy compound storage and conservation. If the response to selection is based on an evolutionarily conserved pattern of genetic correlations (elevated lipid, elevated sugars and reduced movement), then the response to selection is medically relevant and the genetic architecture should be investigated in depth.


Subject(s)
Biological Evolution , Drosophila melanogaster/metabolism , Animals , Body Composition , Body Size , Drosophila melanogaster/anatomy & histology , Drosophila melanogaster/genetics , Female , Food Deprivation , Lipid Metabolism , Male
10.
J Evol Biol ; 23(7): 1386-98, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20500366

ABSTRACT

Sperm storage organs are common and broadly distributed among animal taxa. However, little is known about how these organs function at the molecular level. Additionally, there is a paucity of knowledge about the evolution of genes expressed in these organs. This investigation is an evolutionary expressed sequence tag (EST) study of genes expressed in the seminal receptacle, one of the sperm storage organs in Drosophila. The incidence of positive selection is higher for the seminal receptacle genes than Drosophila reproductive genes as a whole, but lower than genes associated with the spermatheca, a second type of Drosophila sperm storage organ. By identifying overrepresented classes of proteins and classes for which sperm storage function is suggested by the nature of the proteins, candidate genes were discovered. These candidates belong to protein classes such as muscle contraction, odorant binding and odorant receptor, protease inhibitor and immunity.


Subject(s)
Drosophila melanogaster/genetics , Expressed Sequence Tags , Genes, Insect/genetics , Genitalia, Female/metabolism , Animals , Base Sequence , DNA, Complementary/genetics , Drosophila melanogaster/metabolism , Evolution, Molecular , Female , Likelihood Functions , Models, Genetic , Molecular Sequence Data , Sequence Alignment , Sequence Analysis, DNA
11.
Insect Mol Biol ; 18(4): 465-75, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19453766

ABSTRACT

The occurrence of female sperm storage across taxa indicates the importance of this complex and dynamic process. Organs responsible for sperm storage (SSOs) and proteins expressed therein, are important in fundamental aspects of reproduction and could play a major role in evolutionary processes such as post-mating sexual selection. Given the essential role of SSOs, it is surprising that the process of sperm storage is so poorly understood. This study investigated the transcriptome of female Drosophila melanogaster SSOs (seminal receptacle and spermathecae). Spermathecae were enriched for proteases and metabolic enzymes while the seminal receptacle was enriched for genes involved in localization, signaling and ion transport. Differences in functional gene categories indicate that these organs play unique roles in sperm storage.


Subject(s)
Drosophila melanogaster/metabolism , Gene Expression Profiling , Genitalia, Female/metabolism , Animals , Cluster Analysis , Cytochrome P-450 Enzyme System/metabolism , Drosophila melanogaster/genetics , Female , Gene Expression Regulation/physiology , Insect Hormones/metabolism , Male , Reproduction/physiology , Spermatozoa
12.
Insect Biochem Mol Biol ; 37(12): 1359-65, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17967354

ABSTRACT

The 458 amino acid sequence of a mature JHE protein from the cricket Gryllus assimilis was identified after isolating the partial cDNA sequence encoding this protein from a fat body and midgut cDNA library. This hemimetabolan JHE sequence shows over 40% amino acid similarity to the known JHE sequences of several holometabolous insects. It also includes previously determined peptide sequences for G. assimilis JHE as well as two other motifs associated with JHE enzymes in holometabolous insects. The predicted molecular weight of the protein agrees with that of the JHE previously purified from G. assimilis. Partial genomic sequence encoding the Jhe contains two large (1330 and 2918bp) introns. No coding DNA sequence variation was observed over a 1293bp region between selected lines differing six to eight-fold in hemolymph JHE activity. However, a 19bp indel was found in one of the introns; the insertion was strongly associated with elevated hemolymph activity, both in the selected lines and in the F(2) progeny of crosses between them. Phylogenetic analyses localised the G. assimilis JHE to a clade containing dipteran and coleopteran JHEs, with lepidopteran JHEs occurring in a separate clade.


Subject(s)
Carboxylic Ester Hydrolases/metabolism , Fat Body/enzymology , Gryllidae/enzymology , Hemolymph/enzymology , Amino Acid Sequence , Animals , Base Sequence , Carboxylic Ester Hydrolases/genetics , Carboxylic Ester Hydrolases/isolation & purification , Cloning, Molecular , Gastrointestinal Tract/enzymology , Gene Library , Gryllidae/chemistry , Gryllidae/genetics , Introns , Isoenzymes/genetics , Isoenzymes/isolation & purification , Isoenzymes/metabolism , Molecular Probe Techniques , Molecular Sequence Data , Phylogeny , Selection, Genetic , Sequence Analysis, DNA , Structure-Activity Relationship
13.
Heredity (Edinb) ; 99(3): 313-21, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17593945

ABSTRACT

Identification of genes underlying complex traits is an important problem. Quantitative trait loci (QTL) are mapped using marker-trait co-segregation in large panels of recombinant genotypes. Most frequently, recombinant inbred lines derived from two isogenic parents are used. Segregation patterns are also studied in pedigrees from multiple families. Great advances have been made through creative use of these techniques, but narrow sampling and inadequate power represent strong limitations. Here, we propose an approach combining the strengths of both techniques. We established a mapping population from a sample of natural genotypes, and applied artificial selection for a complex character. Selection changed the frequencies of alleles in QTLs contributing to the selection response. We infer QTLs with dense genotyping microarrays by identifying blocks of linked markers undergoing selective changes in allele frequency. We demonstrated this approach with an experimental population composed from 20 isogenic strains. Selection for starvation survival was executed in three replicated populations with three control non-selected populations. Three individuals per population were genotyped using Affymetrix GeneChips. Two regions of the genome, one each on the left arms of the second and third chromosomes, showed significant divergence between control and selected populations. For the former region, we inferred allele frequencies in selected and control populations by pyrosequencing. We conclude that the allele frequency difference, averaging approximately 40% between selected and control lines, contributed to selection response. Our approach can contribute to the fine scale decomposition of the genetics of direct and indirect selection responses, and genotype by environment interactions.


Subject(s)
Alleles , Chromosome Mapping , Drosophila melanogaster/genetics , Gene Frequency/genetics , Genome, Insect/physiology , Quantitative Trait Loci/genetics , Animals , Female , Genetics, Population , Inbreeding , Male , Selection, Genetic
14.
Evolution ; 55(8): 1600-8, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11580019

ABSTRACT

Little is known about physiological mechanisms that underlie the cost of reproduction. We tested the hypothesis that stress susceptibility is a cost of reproduction. In one test of our hypothesis, Drosophila melanogaster females were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster was employed as a control for reproduction. Exposure of fertile females to methoprene resulted in an increase in female reproduction and increased susceptibility to oxidative stress and starvation (compared to solvent controls). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated egg production. As a second test of our hypothesis, mated females were compared to virgin females. Mated fertile females were relatively susceptible to oxidative stress, but this relationship was not evident when mated and virgin sterile females were compared. The results of the present study support the hypothesis that stress susceptibility is a cost of reproduction.


Subject(s)
Drosophila melanogaster/physiology , Oocytes/physiology , Oxidative Stress/physiology , Animals , Drosophila melanogaster/drug effects , Drosophila melanogaster/genetics , Female , Free Radicals/metabolism , Herbicides/pharmacology , Male , Methoprene/pharmacology , Mortality , Paraquat/pharmacology , Reproduction , Starvation
15.
Exp Gerontol ; 36(8): 1349-59, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11602209

ABSTRACT

The present study tests the hypothesis that reproduction is correlated with decreased oxidative stress resistance. In numerous species, it has been observed that longevity is negatively correlated with reproduction but the physiological basis of this cost is not well understood. In the present study, female egg production was stimulated by adding live yeast to the surface of Drosophila food. After females were held on yeast-supplemented and unmodified medium for 6-12 days, susceptibility to oxidative stress was measured by exposure to methyl viologen. Added yeast was associated with stress susceptibility of fertile females but not of sterile females. The results of the present study suggest that oxidative stress susceptibility is a physiological cost of reproduction.


Subject(s)
Drosophila melanogaster/physiology , Oogenesis/physiology , Oxidative Stress , Aging/metabolism , Animals , Female , Fertility/physiology , Infertility, Female/metabolism , Longevity/physiology , Models, Biological , Reproduction/physiology
16.
Science ; 292(5514): 104-6, 2001 Apr 06.
Article in English | MEDLINE | ID: mdl-11292874

ABSTRACT

The Drosophila melanogaster gene chico encodes an insulin receptor substrate that functions in an insulin/insulin-like growth factor (IGF) signaling pathway. In the nematode Caenorhabditis elegans, insulin/IGF signaling regulates adult longevity. We found that mutation of chico extends fruit fly median life-span by up to 48% in homozygotes and 36% in heterozygotes. Extension of life-span was not a result of impaired oogenesis in chico females, nor was it consistently correlated with increased stress resistance. The dwarf phenotype of chico homozygotes was also unnecessary for extension of life-span. The role of insulin/IGF signaling in regulating animal aging is therefore evolutionarily conserved.


Subject(s)
Aging/physiology , Drosophila Proteins , Drosophila melanogaster/physiology , Insect Proteins/genetics , Insect Proteins/metabolism , Intracellular Signaling Peptides and Proteins , Longevity/physiology , Receptor Protein-Tyrosine Kinases , Receptor, Insulin/metabolism , Alleles , Animals , Body Constitution , Carrier Proteins/genetics , Carrier Proteins/metabolism , Crosses, Genetic , Drosophila melanogaster/genetics , Female , Fertility , Genes, Insect , Heterozygote , Hot Temperature , Insulin/metabolism , Insulin Receptor Substrate Proteins , Male , Mutation , Oxidative Stress , Protein-Tyrosine Kinases/genetics , Protein-Tyrosine Kinases/metabolism , Reproduction , Signal Transduction , Somatomedins/metabolism , Starvation , Superoxide Dismutase
17.
J Gerontol A Biol Sci Med Sci ; 56(2): B89-93, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11213272

ABSTRACT

Large-scale experiments on medflies that were subjected to sterilizing doses of ionizing radiation (plus intact controls) and maintained on either sugar-only or full, protein-enriched diets revealed that, whereas the mortality trajectories of both intact and irradiated male cohorts maintained on both diets are similar, the mortality patterns of females are highly variable. Mean mortality rates at 35 days in male cohorts ranged from 0.2 to 0.3 but in female cohorts ranged from 0.09 to 0.35, depending on treatment. The study reports three main influences: (a) qualitative differences exist in the sex-mortality response of medflies subjected to dietary manipulations and irradiation; (b) the female mortality response is linked to increased vulnerability due to the nutritional demands of reproduction; and (c) female sensitivity to environmental changes underlies the dynamics of the sex-mortality differential.


Subject(s)
Diet , Diptera/physiology , Diptera/radiation effects , Sex Characteristics , Animals , Carbohydrates/pharmacology , Dietary Proteins/pharmacology , Diptera/drug effects , Female , Life Expectancy , Male , Mortality , Reproduction/physiology , Sex Distribution
18.
J Gerontol A Biol Sci Med Sci ; 55(9): B415-7, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10995037

ABSTRACT

Stress resistance is associated with longevity in Drosophila melanogaster and other model organisms used for genetic research. The present study tests for oxidative stress resistance in one set of lines selected for late-life reproduction and extended longevity. Both females and males from the selected lines were appreciably more resistant to oxidative stress than were flies from the control lines. A relative increase in oxidative stress resistance is a correlated response to selection in this laboratory selection experiment. Increased oxidative stress resistance appears to be a relatively robust correlated response to laboratory selection for late-life reproduction and extended longevity.


Subject(s)
Longevity , Oxidative Stress/physiology , Selection, Genetic , Analysis of Variance , Animals , Drosophila melanogaster , Female , Herbicides/adverse effects , Longevity/drug effects , Longevity/genetics , Male , Oxidative Stress/drug effects , Oxidative Stress/genetics , Paraquat/adverse effects , Reproduction/genetics , Survival Rate , Water
19.
J Gerontol A Biol Sci Med Sci ; 54(10): B432-40, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10568526

ABSTRACT

Vitellogenic and previtellogenic oocyte stages, as well as ovariole numbers, were characterized in the selected (O) lines of D. melanogaster that have been selected for late-life reproduction and extended longevity. On day 4 post-eclosion, O females had more ovarioles than control (B) females, but this difference diminished at older ages. From days 4 to 24, O females showed a marked increase in average vitellogenic oocyte stage, whereas this parameter did not increase in B females as they aged. The previtellogenic gradient of oocyte maturation declined in both B and O females. Specifically, terminal previtellogenic stages were lost with advancing age, and this loss occurred relatively gradually in O females regardless of food regime. Among the reproductive traits assessed, differential persistence of the previtellogenic gradient of maturation is most strongly associated with selected versus control line differences in longevity.


Subject(s)
Drosophila melanogaster/physiology , Longevity/physiology , Ovary/cytology , Aging/physiology , Animals , Diet , Drosophila melanogaster/anatomy & histology , Female , Oocytes/cytology , Oocytes/growth & development , Oogenesis , Ovary/physiology , Reproduction/physiology , Vitellogenesis
20.
Exp Gerontol ; 34(2): 173-84, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10363785

ABSTRACT

Lines of Drosophila melanogaster selected for late-life female reproduction typically exhibit correlated responses of reduced early fecundity and increased longevity. This relationship suggests a tradeoff between reproductive effort and somatic maintenance, which in turn, underlies some evolutionary theories of senescence. The mechanistic basis of the apparent tradeoff between increased longevity and reduced early-age fecundity has remained obscure. The present manuscript addresses the issues of whether the reduced early-age fecundity in selected lines corresponds to reduced yolk-protein mRNA production, and whether long-lived flies exhibit somatic maintenance in terms of relatively reduced yolk-protein mRNA production in the fat body. Yolk protein is one of the most abundant proteins used for female reproduction. By comparing a set of lines selected for late life reproduction with the corresponding control lines, we show that that yolk-protein gene mRNA relative abundance during the first four days posteclosion did not correspond to reduced early-life fecundity in the selected lines. In D. melanogaster, yolk protein is produced in the fat body and ovarian follicle cells. On the fourth day posteclosion, relatively more yolk-protein gene mRNA was present in the fat body. On day 1 posteclosion, supplemental yeast did not alter relative yolk-protein gene mRNA abundance. However, on day 4 posteclosion, supplemental yeast stimulated yolk-protein gene mRNA production in the fat body, which suggests an underlying mechanism for the nutrition-based phenotypic plasticity of fecundity previously documented in these lines. On medium without supplemental yeast, the relatively low abundance of fat body yolk-protein gene mRNA in the selected lines on day 4 posteclosion corresponds to a prediction derived from the disposable soma theory.


Subject(s)
Drosophila melanogaster/genetics , Egg Proteins/genetics , Longevity/genetics , Aging/genetics , Aging/physiology , Animals , Drosophila melanogaster/physiology , Fat Body/metabolism , Female , Fertility/genetics , Fertility/physiology , Longevity/physiology , Ovary/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...