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1.
Cureus ; 16(8): e65938, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39221397

RESUMO

Background The United States Agency for International Development (USAID) Reaching Impact, Saturation, and Epidemic Control (RISE) program funded Jhpiego to support the Government of Lesotho's COVID-19 response, including two national COVID-19 treatment centers. To evaluate the status of post-pandemic pediatric respiratory care in Lesotho, we analyzed pediatric treatment center data and healthcare worker (HCW) performance on pediatric COVID-19 training offered to HCWs at COVID-19 treatment centers. Methods We conducted a retrospective cohort study of patients 15 years of age or less hospitalized at two COVID-19 treatment centers in Lesotho from May 1, 2020, to April 30, 2022. Patient data were extracted from hospital files. We used the independent sample t-test, Mann-Whitney U test, or Fisher's exact test to evaluate associations between exposure variables and death. We also assessed differences between pre- and post-training examination scores of three one-day HCW training on pediatric COVID-19 using paired t-tests. Results Overall, <15-year-olds comprised 18/1,448 (1.2%) hospitalizations. Twenty-two percent (4/18) of children were hypoxemic (oxyhemoglobin saturation <94%) within the first 24 hours and 44% (8/18) at any point in the hospitalization. Oxygen utilization increased over the two-year period (p=0.004) and all eight children with hypoxemia received oxygen (p<0.001). Four of 18 (22%) patients died. For HCW training, pre- and post-training examinations were completed by 76/82 (92.7%) participants. The overall mean pretraining score was 44.6% (standard deviation (SD) 15.7%). Mean scores improved by an average of 32.2% (95% confidence interval (CI) 27.7%, 36.6%, p<0.001) on the same day post-training examination. Conclusions National COVID-19 treatment center data indicate a low burden of severe pediatric COVID-19 disease in Lesotho. However, recognized HCW knowledge gaps suggest deficiencies in identifying and referring severely ill children, which may detrimentally impact the ongoing post-pandemic care of children with severe lower respiratory infections.

2.
Health Aff (Millwood) ; 43(8): 1137-1146, 2024 08.
Artigo em Inglês | MEDLINE | ID: mdl-39102598

RESUMO

Nearly all patients with type 1 diabetes and 20-30 percent of patients with type 2 diabetes use insulin to manage glycemic control. Approximately one-quarter of patients who use insulin report underuse because of cost. In response, more than twenty states have implemented monthly caps on insulin out-of-pocket spending, ranging from $25 to $100. Using a difference-in-differences approach, this study evaluated whether state-level caps on insulin out-of-pocket spending change insulin usage among commercially insured enrollees. The study included 33,134 people ages 18-64 who had type 1 diabetes or who used insulin to manage type 2 diabetes with commercial insurance coverage that was subject to state-level oversight and was included in the 25 percent sample of the IQVIA PharMetrics database during 2018-21. Insulin out-of-pocket caps did not significantly increase quarterly insulin claims for enrollees who had type 1 diabetes or who used insulin to manage type 2 diabetes. State-level caps on insulin out-of-pocket spending for commercial enrollees did not significantly increase insulin use; that may be in part because of out-of-pocket expenses being lower than cap amounts.


Assuntos
Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Gastos em Saúde , Hipoglicemiantes , Insulina , Humanos , Insulina/uso terapêutico , Insulina/economia , Feminino , Pessoa de Meia-Idade , Adulto , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/economia , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/economia , Masculino , Estados Unidos , Gastos em Saúde/estatística & dados numéricos , Hipoglicemiantes/uso terapêutico , Hipoglicemiantes/economia , Adolescente , Revisão da Utilização de Seguros , Cobertura do Seguro/estatística & dados numéricos , Adulto Jovem , Seguro Saúde/economia , Seguro Saúde/estatística & dados numéricos , Custos de Medicamentos/estatística & dados numéricos
3.
Clin Infect Dis ; 79(2): 354-363, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-38690892

RESUMO

BACKGROUND: Metformin has antiviral activity against RNA viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The mechanism appears to be suppression of protein translation via targeting the host mechanistic target of rapamycin pathway. In the COVID-OUT randomized trial for outpatient coronavirus disease 2019 (COVID-19), metformin reduced the odds of hospitalizations/death through 28 days by 58%, of emergency department visits/hospitalizations/death through 14 days by 42%, and of long COVID through 10 months by 42%. METHODS: COVID-OUT was a 2 × 3 randomized, placebo-controlled, double-blind trial that assessed metformin, fluvoxamine, and ivermectin; 999 participants self-collected anterior nasal swabs on day 1 (n = 945), day 5 (n = 871), and day 10 (n = 775). Viral load was quantified using reverse-transcription quantitative polymerase chain reaction. RESULTS: The mean SARS-CoV-2 viral load was reduced 3.6-fold with metformin relative to placebo (-0.56 log10 copies/mL; 95% confidence interval [CI], -1.05 to -.06; P = .027). Those who received metformin were less likely to have a detectable viral load than placebo at day 5 or day 10 (odds ratio [OR], 0.72; 95% CI, .55 to .94). Viral rebound, defined as a higher viral load at day 10 than day 5, was less frequent with metformin (3.28%) than placebo (5.95%; OR, 0.68; 95% CI, .36 to 1.29). The metformin effect was consistent across subgroups and increased over time. Neither ivermectin nor fluvoxamine showed effect over placebo. CONCLUSIONS: In this randomized, placebo-controlled trial of outpatient treatment of SARS-CoV-2, metformin significantly reduced SARS-CoV-2 viral load, which may explain the clinical benefits in this trial. Metformin is pleiotropic with other actions that are relevant to COVID-19 pathophysiology. CLINICAL TRIALS REGISTRATION: NCT04510194.


Assuntos
Antivirais , Tratamento Farmacológico da COVID-19 , COVID-19 , Metformina , SARS-CoV-2 , Carga Viral , Humanos , Metformina/uso terapêutico , Metformina/farmacologia , Carga Viral/efeitos dos fármacos , Masculino , SARS-CoV-2/efeitos dos fármacos , Feminino , Pessoa de Meia-Idade , Método Duplo-Cego , Antivirais/uso terapêutico , Antivirais/farmacologia , Adulto , COVID-19/virologia , Ivermectina/uso terapêutico , Ivermectina/farmacologia , Fluvoxamina/uso terapêutico , Fluvoxamina/farmacologia , Idoso
4.
J Genet ; 1032024.
Artigo em Inglês | MEDLINE | ID: mdl-38258319

RESUMO

Dissecting the molecular basis of adaptation remains elusive despite our ability to sequence genomes and transcriptomes. At present, most genomic research on selection focusses on signatures of selective sweeps in patterns of heterozygosity. Other research has studied changes in patterns of gene expression in evolving populations but has not usually identified the genetic changes causing these shifts in expression. Here we attempt to go beyond these approaches by using machine learning tools to explore interactions between the genome, transcriptome, and life-history phenotypes in two groups of 10 experimentally evolved Drosophila populations subjected to selection for opposing life history patterns. Our findings indicate that genomic and transcriptomic data have comparable power for predicting phenotypic characters. Looking at the relationships between the genome and the transcriptome, we find that the expression of individual transcripts is influenced by many sites across the genome that are differentiated between the two types of populations. We find that single-nucleotide polymorphisms (SNPs), transposable elements, and indels are powerful predictors of gene expression. Collectively, our results suggest that the genomic architecture of adaptation is highly polygenic with extensive pleiotropy.


Assuntos
Drosophila , Genômica , Animais , Drosophila/genética , Perfilação da Expressão Gênica , Heterozigoto , Mutação INDEL
6.
JAMA ; 330(23): 2297-2298, 2023 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-38039053

RESUMO

A 72-year-old man presented to the emergency department with fevers, night sweats, and rash 3 days after condomless vaginal intercourse. Results of a fourth-generation HIV test were positive and HIV-1-/2 antibody differentiation testing was negative. How would you interpret these results?


Assuntos
Infecções por HIV , Teste de HIV , Humanos , Infecções por HIV/diagnóstico , Teste de HIV/métodos
7.
Neurology ; 101(20): 907-908, 2023 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-37748893
8.
medRxiv ; 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37333243

RESUMO

Current antiviral treatment options for SARS-CoV-2 infections are not available globally, cannot be used with many medications, and are limited to virus-specific targets.1-3 Biophysical modeling of SARS-CoV-2 replication predicted that protein translation is an especially attractive target for antiviral therapy.4 Literature review identified metformin, widely known as a treatment for diabetes, as a potential suppressor of protein translation via targeting of the host mTor pathway.5 In vitro, metformin has antiviral activity against RNA viruses including SARS-CoV-2.6,7 In the COVID-OUT phase 3, randomized, placebo-controlled trial of outpatient treatment of COVID-19, metformin had a 42% reduction in ER visits/hospitalizations/death through 14 days; a 58% reduction in hospitalizations/death through 28 days, and a 42% reduction in Long COVID through 10 months.8,9 Here we show viral load analysis of specimens collected in the COVID-OUT trial that the mean SARS-CoV-2 viral load was reduced 3.6-fold with metformin relative to placebo (-0.56 log10 copies/mL; 95%CI, -1.05 to -0.06, p=0.027) while there was no virologic effect for ivermectin or fluvoxamine vs placebo. The metformin effect was consistent across subgroups and with emerging data.10,11 Our results demonstrate, consistent with model predictions, that a safe, widely available,12 well-tolerated, and inexpensive oral medication, metformin, can be repurposed to significantly reduce SARS-CoV-2 viral load.

9.
Lancet Infect Dis ; 23(10): 1119-1129, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37302406

RESUMO

BACKGROUND: Post-COVID-19 condition (also known as long COVID) is an emerging chronic illness potentially affecting millions of people. We aimed to evaluate whether outpatient COVID-19 treatment with metformin, ivermectin, or fluvoxamine soon after SARS-CoV-2 infection could reduce the risk of long COVID. METHODS: We conducted a decentralised, randomised, quadruple-blind, parallel-group, phase 3 trial (COVID-OUT) at six sites in the USA. We included adults aged 30-85 years with overweight or obesity who had COVID-19 symptoms for fewer than 7 days and a documented SARS-CoV-2 positive PCR or antigen test within 3 days before enrolment. Participants were randomly assigned via 2 × 3 parallel factorial randomisation (1:1:1:1:1:1) to receive metformin plus ivermectin, metformin plus fluvoxamine, metformin plus placebo, ivermectin plus placebo, fluvoxamine plus placebo, or placebo plus placebo. Participants, investigators, care providers, and outcomes assessors were masked to study group assignment. The primary outcome was severe COVID-19 by day 14, and those data have been published previously. Because the trial was delivered remotely nationwide, the a priori primary sample was a modified intention-to-treat sample, meaning that participants who did not receive any dose of study treatment were excluded. Long COVID diagnosis by a medical provider was a prespecified, long-term secondary outcome. This trial is complete and is registered with ClinicalTrials.gov, NCT04510194. FINDINGS: Between Dec 30, 2020, and Jan 28, 2022, 6602 people were assessed for eligibility and 1431 were enrolled and randomly assigned. Of 1323 participants who received a dose of study treatment and were included in the modified intention-to-treat population, 1126 consented for long-term follow-up and completed at least one survey after the assessment for long COVID at day 180 (564 received metformin and 562 received matched placebo; a subset of participants in the metformin vs placebo trial were also randomly assigned to receive ivermectin or fluvoxamine). 1074 (95%) of 1126 participants completed at least 9 months of follow-up. 632 (56·1%) of 1126 participants were female and 494 (43·9%) were male; 44 (7·0%) of 632 women were pregnant. The median age was 45 years (IQR 37-54) and median BMI was 29·8 kg/m2 (IQR 27·0-34·2). Overall, 93 (8·3%) of 1126 participants reported receipt of a long COVID diagnosis by day 300. The cumulative incidence of long COVID by day 300 was 6·3% (95% CI 4·2-8·2) in participants who received metformin and 10·4% (7·8-12·9) in those who received identical metformin placebo (hazard ratio [HR] 0·59, 95% CI 0·39-0·89; p=0·012). The metformin beneficial effect was consistent across prespecified subgroups. When metformin was started within 3 days of symptom onset, the HR was 0·37 (95% CI 0·15-0·95). There was no effect on cumulative incidence of long COVID with ivermectin (HR 0·99, 95% CI 0·59-1·64) or fluvoxamine (1·36, 0·78-2·34) compared with placebo. INTERPRETATION: Outpatient treatment with metformin reduced long COVID incidence by about 41%, with an absolute reduction of 4·1%, compared with placebo. Metformin has clinical benefits when used as outpatient treatment for COVID-19 and is globally available, low-cost, and safe. FUNDING: Parsemus Foundation; Rainwater Charitable Foundation; Fast Grants; UnitedHealth Group Foundation; National Institute of Diabetes, Digestive and Kidney Diseases; National Institutes of Health; and National Center for Advancing Translational Sciences.


Assuntos
COVID-19 , Metformina , Adulto , Gravidez , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Incidência , Ivermectina/uso terapêutico , Síndrome de COVID-19 Pós-Aguda , Tratamento Farmacológico da COVID-19 , Fluvoxamina , Pacientes Ambulatoriais , SARS-CoV-2 , Metformina/uso terapêutico , Método Duplo-Cego , Resultado do Tratamento
10.
Physiol Biochem Zool ; 96(3): 192-205, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37278586

RESUMO

Drosophila experimental evolution, with its well-defined selection protocols, has long supplied useful genetic material for the analysis of functional physiology. While there is a long tradition of interpreting the effects of large-effect mutants physiologically, identifying and interpreting gene-to-phenotype relationships has been challenging in the genomic era, with many labs not resolving how physiological traits are affected by multiple genes throughout the genome. Drosophila experimental evolution has demonstrated that multiple phenotypes change because of the evolution of many loci across the genome, creating the scientific challenge of sifting out differentiated but noncausal loci for individual characters. The fused lasso additive model method allows us to infer some of the differentiated loci that have relatively greater causal effects on the differentiation of specific phenotypes. The experimental material that we use in the present study comes from 50 populations that have been selected for different life histories and levels of stress resistance. Differentiation of cardiac robustness, starvation resistance, desiccation resistance, lipid content, glycogen content, water content, and body masses was assayed among 40-50 of these experimentally evolved populations. Through the fused lasso additive model, we combined physiological analyses from eight parameters with whole-body pooled-seq genomic data to identify potentially causally linked genomic regions. We have identified approximately 2,176 significantly differentiated 50-kb genomic windows among our 50 populations, with 142 of those identified genomic regions that are highly likely to have a causal effect connecting specific genome sites to specific physiological characters.


Assuntos
Drosophila , Inanição , Animais , Drosophila/genética , Drosophila melanogaster/genética , Fenótipo , Aprendizado de Máquina
12.
J Clin Neurol ; 18(5): 514-521, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36062768

RESUMO

BACKGROUND AND PURPOSE: The Individualized Neuromuscular Quality of Life questionnaire (INQoL) is a widely used measure of the quality of life in patients with neuromuscular diseases. The purpose of this study was to translate and validate the Korean version of INQoL in Korean patients with neuromuscular diseases. METHODS: We translated the original INQoL version into Korean while applying appropriate language adaptations. The internal consistency, known-group validity, and test-retest reliability were also assessed. Construct validity was measured using the modified Rankin Scale (mRS) score and the manual muscle testing (MMT)-sum score based on the Medical Research Council scale, and concurrent validity was measured using the 36-item Short Form Survey (SF-36) questionnaire. RESULTS: This study enrolled 193 patients. The coefficients for internal consistency (Cronbach's α=0.805 to 0.987) and test-retest reliability (Spearman's ρ=0.453 to 0.886) were adequately high for all subscales except in the 'treatment effects' dimension. INQoL subscales other than those for locking, droopy eyelids, double vision, and swallowing difficulties were significantly associated with their relevant SF-36 domains (Spearman's ρ=-0.274 to -0.833). Functional status and muscle strength were most strongly associated with independence (Spearman's ρ=0.753 and p<0.001 for mRS score, Spearman's ρ=-0.741 and p<0.001 for MMT-sum score). CONCLUSIONS: The Korean INQoL is a reliable and validated measurement tool for Korean patients with neuromuscular diseases.

13.
WMJ ; 121(4): e66-e70, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36637849

RESUMO

INTRODUCTION: Although histoplasmosis is an extremely rare cause of bowel obstruction, this case describes disseminated gastrointestinal histoplasmosis as it progresses from acute colitis to subacute recurrent bowel obstructions. CASE PRESENTATION: A White man in his early 80s with history of multiple myeloma presented to the emergency department with lightheadedness and diarrhea. Following a diagnostic journey for unspecified colitis, urine antigen testing and endoscopic biopsies led to the diagnosis. During the initial 12 weeks of antifungal treatment, the disease process transitioned from an acute inflammatory syndrome into a recurrent bowel obstruction. DISCUSSION/CONCLUSIONS: Only one other case of histoplasmosis causing recurrent bowel obstruction has been reported; however, that patient succumbed to the disease without surgical intervention. No clear guidelines exist of how to manage bowel obstructions from rare infectious sources, such as histoplasmosis, but close surveillance, multidisciplinary care, and an understanding of gastrointestinal pathology can guide clinicians when encountering atypical etiologies of bowel obstruction.


Assuntos
Colite , Histoplasmose , Obstrução Intestinal , Masculino , Humanos , Histoplasmose/complicações , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Obstrução Intestinal/diagnóstico por imagem , Obstrução Intestinal/etiologia , Obstrução Intestinal/patologia , Biópsia/efeitos adversos
14.
Disabil Rehabil ; 44(23): 7312-7320, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-34606392

RESUMO

PURPOSE: Measuring the physical activity of adults with progressive muscle diseases is important to inform clinical practice, for activity recommendations and for outcomes meaningful to participants in clinical trials. Despite its wide use, the measurement properties of the International Physical Activity Questionnaire (IPAQ) have not been established in a muscle disease population. MATERIALS AND METHODS: The sample of 103 adults with progressive muscle diseases included independently mobile participants and wheelchair users. Their home-based activity measured by the IPAQ was compared to simultaneous weeks of accelerometer activity data collected remotely in a longitudinal, measure evaluation study. Validity, reliability, and responsiveness were evaluated for the IPAQ alone, and for the IPAQ used in conjunction with a smart activity monitor. RESULTS: The IPAQ did not demonstrate satisfactory criterion validity, reliability or responsiveness and it systematically overestimated moderate and vigorous physical activity time by 161 minutes per week. Measurement properties of the IPAQ were improved when it was used in combination with a smart activity monitor. CONCLUSIONS: The IPAQ did not have satisfactory measurement properties compared to accelerometry in adults with progressive muscle disease. Combining self-report and objective activity measures might improve the accuracy of physical activity assessment in this and other comparable populations.Implications for RehabilitationPhysical activity is a meaningful health outcome for adults with progressive muscle diseases, for whom precise activity quantification is important because of the potential for activity-related disease exacerbation.The International Physical Activity Questionnaire (IPAQ) had unsatisfactory measurement properties compared to accelerometry; however, these were improved by adjunctive smart activity monitoring.Objective or combined physical activity measurement is recommended over self-report alone for clinical assessment of physical activity as part of rehabilitation and self-management programmes.


Assuntos
Acelerometria , Exercício Físico , Adulto , Humanos , Reprodutibilidade dos Testes , Inquéritos e Questionários , Exercício Físico/fisiologia , Músculos
15.
Disabil Rehabil ; 44(24): 7543-7553, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-34719329

RESUMO

PURPOSE: Measuring physical activity informs activity recommendations in clinical practice and provides outcomes in clinical trials that are meaningful to patients. Activity assessment in muscle disease is challenging and there is insufficient evidence to support any single activity measure; however, multi-modal activity measurement might have potential. MATERIALS AND METHODS: This two-part study included 20 and 95 adults with progressive muscle diseases with mobility ranging from independent to assisted, including wheelchair users. Their activity was measured using a multi-sensor Fitbit activity monitor, for which criterion validity and acceptability were tested in study 1 and validity, reliability, and responsiveness were tested in the longitudinal, home-based study 2. RESULTS: Study 1: Fitbit was acceptable and had strong criterion validity (rho/kappa ≥0.90), although up to 15% measurement error. Study 2: Fitbit had satisfactory concurrent and construct validity, reliability, and responsiveness. However, Fitbit active minutes registered 75 min more activity per week than gold standard moderate and vigorous physical activity (MVPA) time. CONCLUSIONS: Fitbit had satisfactory measurement properties for monitoring physical activity in adults with progressive muscle diseases. However, Fitbit should not be considered an exact step counter, heart rate monitor or calorimeter and Fitbit active minutes are not synonymous with MVPA time.Implications for rehabilitationPeople with progressive muscle diseases mobilise independently, with walking aids and with wheelchairs; physical activity measurement can be challenging in this population.Multisensor smart activity monitoring by Fitbit had satisfactory validity, reliability, responsiveness, and acceptability for the estimation of physical activity in adults with progressive muscle diseases.Fitbit active minutes are not synonymous with moderate and vigorous physical activity (MVPA) time measured using a research grade accelerometer.


Assuntos
Exercício Físico , Monitores de Aptidão Física , Adulto , Humanos , Reprodutibilidade dos Testes , Exercício Físico/fisiologia , Monitorização Fisiológica , Músculos , Monitorização Ambulatorial , Acelerometria
16.
BMJ Neurol Open ; 3(1): e000140, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34192259

RESUMO

INTRODUCTION: This short article summarises findings about reduced physical activity of adults with progressive muscle disease as a result of COVID-19 lockdown. METHODS: As part of an ongoing longitudinal cohort study, we prospectively and objectively measured physical activity using accelerometry at baseline in 2019 and follow-up in 2020. A subset of 85 participants incidentally had follow-up data collected during the first UK COVID-19 lockdown from 23 March to 4 July 2020. Thus, for this cohort we had activity data from before and during the COVID-19 pandemic and we were able to prospectively and accurately quantify the changes in their physical activity. RESULTS: Our data highlighted reduced overall activity intensity and reduced light activity time in particular. CONCLUSIONS: From our findings, we can infer specific evidence-based recommendations about how to redress inactivity secondary to COVID-19 restrictions for adults with progressive muscle diseases. These recommendations are likely to be generalisable to other groups who are vulnerable to functional decline secondary to prolonged inactivity.

17.
Rejuvenation Res ; 24(5): 331-344, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32924860

RESUMO

Healthspan science aims to add healthy, functional years to human life. Many different methods of improving healthspan have been investigated, chiefly focusing on just one aspect of an organism's health such as survival. Studies in Drosophila melanogaster have demonstrated that a reversal to a long-abandoned ancestral diet results in improved functional health, particularly at later ages. Meanwhile, pharmaceutical studies have demonstrated that botanical extracts have potent antiaging properties, capable of extending the mean lifespan of D. melanogaster by up to 25%, without a decrease in early fecundity. In this study, we combine these two different approaches to healthspan extension to examine whether a combination of such treatments results in a synergistic or antagonistic effect on Drosophila healthspan. One botanical extract, derived from Rhodiola rosea, mimicked the effects of the ancestral apple diet with better performance at later ages compared with the control. Another extract, derived from Rosa damascena, decreased age-specific survivorship when combined with the apple diet providing support for the "Poisoned Chalice" hypothesis that combinations of various supplements or diets can elicit adverse physiological responses. More experiments in model organisms should be completed researching the effects of combining healthspan-extending substances in various diet backgrounds.


Assuntos
Drosophila melanogaster , Longevidade , Animais , Dieta , Suplementos Nutricionais , Fertilidade
18.
PLoS One ; 15(10): e0240132, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33007000

RESUMO

Our intuitive understanding of adaptation by natural selection is dominated by the power of selection at early ages in large populations. Yet, as the forces of natural selection fall with adult age, we expect adaptation to be attenuated with age. Explicit simulations of age-dependent adaptation suggest that populations adapt to a novel environment quickly at early ages, but only slowly and incompletely at later adult ages. Experimental tests for age-dependent adaptation to a novel diet were performed on populations of Drosophila melanogaster. The results support the prediction that populations should perform better on an ancestral, long-abandoned diet, compared to an evolutionarily recent diet, only at later ages. D. melanogaster populations also perform poorly on a novel diet compared to an evolutionarily recent diet that has been sustained for hundreds of generations, particularly at earlier ages. Additional experiments demonstrate that the timing of the shift to better performance in our populations on the long-abandoned diet is dependent on when the forces of natural selection weaken in the evolutionary history of experimental populations. Taken together, these experimental findings suggest that the forces of natural selection scale the rate of adaptation to novel environments.


Assuntos
Adaptação Fisiológica , Envelhecimento/fisiologia , Drosophila melanogaster/fisiologia , Meio Ambiente , Modelos Biológicos , Animais , Dieta , Modelos Lineares
20.
Physiol Biochem Zool ; 92(6): 591-611, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31603376

RESUMO

In experimental evolution, we impose functional demands on laboratory populations of model organisms using selection. After enough generations of such selection, the resulting populations constitute excellent material for physiological research. An intense selection regime for increased starvation resistance was imposed on 10 large outbred Drosophila populations. We observed the selection responses of starvation and desiccation resistance, metabolic reserves, and heart robustness via electrical pacing. Furthermore, we sequenced the pooled genomes of these populations. As expected, significant increases in starvation resistance and lipid content were found in our 10 intensely selected SCO populations. The selection regime also improved desiccation resistance, water content, and glycogen content among these populations. Additionally, the average rate of cardiac arrests in our 10 obese SCO populations was double the rate of the 10 ancestral CO populations. Age-specific mortality rates were increased at early adult ages by selection. Genomic analysis revealed a large number of single nucleotide polymorphisms across the genome that changed in frequency as a result of selection. These genomic results were similar to those obtained in our laboratory from less direct selection procedures. The combination of extensive genomic and phenotypic differentiation between these 10 populations and their ancestors makes them a powerful system for the analysis of the physiological underpinnings of starvation resistance.


Assuntos
Drosophila melanogaster/genética , Genômica , Longevidade , Adaptação Fisiológica , Animais , Peso Corporal , Drosophila melanogaster/metabolismo , Regulação da Expressão Gênica , Metabolismo dos Lipídeos , Seleção Genética , Inanição
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