Several hypotheses have been put forward to explain the evolution of senescence. One of the leading hypotheses, the disposable soma hypothesis, predicts a trade‐off, whereby early‐life investment in ...reproduction leads to late‐life declines in survival (survival senescence). Testing this hypothesis in natural populations is challenging, but important for understanding the evolution of senescence. We used the long‐term data set from a contained, predator‐free population of individually marked Seychelles warblers (Acrocephalus sechellensis) to investigate how age‐related declines in survival are affected by early‐life investment in reproduction and early‐life environmental conditions. The disposable soma hypothesis predicts that higher investment in reproduction, or experiencing harsh conditions during early life, will lead to an earlier onset, and an increased rate, of senescence. We found that both sexes showed similar age‐related declines in late‐life survival consistent with senescence. Individuals that started breeding at a later age showed a delay in survival senescence, but this later onset of breeding did not result in a less rapid decline in late‐life survival. Although survival senescence was not directly related to early‐life environmental conditions, age of first breeding increased with natal food availability. Therefore, early‐life food availability may affect senescence by influencing age of first breeding. The disposable soma hypothesis of senescence is supported by delayed senescence in individuals that started breeding at a later age and therefore invested less in reproduction.
PurposeThe aim of this study was to determine a sequence of structural changes in acute posterior multifocal placoid pigment epitheliopathy (APMPPE) using optical coherence tomography-angiography ...(OCT-A) and comparing with other imaging modalities.Patients and methodsPatients with a new diagnosis of acute-onset APMPPE referred to a regional specialist centre from October 2015 to October 2016 were included. Multimodal imaging employed on all patients from diagnosis included the following: fundus fluorescein angiography, indocyanine green angiography, fundus autofluorescence, spectral domain-OCT (SD-OCT), and OCT-A. All non-invasive imaging processes were repeated during follow-up.ResultsTen eyes of five patients were included in the study, three males and two females, with a mean age of 26.2 years (range: 21-32) and a mean follow-up of 6.4 months (range: 2.6-13.3). All patients presented with bilateral disease and macular involving lesions. OCT-A imaging of the choriocapillaris was supportive of hypoperfusion at the site of APMPPE lesions during the acute phase of this condition with normalisation of choroidal vasculature during follow-up. Multimodal imaging consistently highlighted four sequential phases from presentation to resolution of active disease.ConclusionsMultimodal imaging in patients with APMPPE in acute and long-term follow-up demonstrates a reversible choroidal hypoperfusion supporting the primary inciting pathology as a choriocapillaritis. The evolution shows resolution of the ischaemia through a defined sequence that results in persistent changes at the level of the retinal pigment epithelium and outer retina. OCT-A was able to detect preclinical changes and chart resolution at the level of the choriocapillaris.
An Integrated Nanoliter DNA Analysis Device Burns, Mark A.; Johnson, Brian N.; Brahmasandra, Sundaresh N. ...
Science (American Association for the Advancement of Science),
10/1998, Letnik:
282, Številka:
5388
Journal Article
Recenzirano
A device was developed that uses microfabricated fluidic channels, heaters, temperature sensors, and fluorescence detectors to analyze nanoliter-size DNA samples. The device is capable of measuring ...aqueous reagent and DNA-containing solutions, mixing the solutions together, amplifying or digesting the DNA to form discrete products, and separating and detecting those products. No external lenses, heaters, or mechanical pumps are necessary for complete sample processing and analysis. Because all of the components are made using conventional photolithographic production techniques, they operate as a single closed system. The components have the potential for assembly into complex, low-power, integrated analysis systems at low unit cost. The availability of portable, reliable instruments may facilitate the use of DNA analysis in applications such as rapid medical diagnostics and point-of-use agricultural testing.
Plague is an infectious disease with a high mortality rate that has repeatedly impacted human society. It remains a threat in many parts of the world today. Plague is caused by the bacterium, ...Yersinia pestis (Y. pestis), which has as one of its required virulence factors, the protein-tyrosine phosphatase, YopH. Therefore, YopH represents a potential target for the treatment of Y. pestis infection. Recent recognition of Y. pestis as a possible bioterrorism agent and the fact that it is still the cause of endemic disease around the world make it an important object of study and heighten the need for new anti-plague agents. The current review covers aspects of plague and its historical occurrence and summarizes approaches to developing YopH inhibitors.
In cases of brain pathology, current levels of cognition can only be interpreted reliably relative to accurate estimations of pre-morbid functioning. Estimating levels of pre-morbid intelligence is, ...therefore, a crucial part of neuropsychological evaluation. However, current methods of estimation have proven problematic.
To evaluate if standardised leaving certificate (LC) performance can predict intellectual functioning in a healthy cohort. The LC is the senior school examination in the Republic of Ireland, taken by almost 50 000 students annually, with total performance distilled into Central Applications Office points.
A convenience sample of university students was recruited (
= 51), to provide their LC results and basic demographic information. Participants completed two cognitive tasks assessing current functioning (Vocabulary and Matrix Reasoning (MR) subtests - Wechsler Abbreviated Scale of Intelligence, Second Edition) and a test of pre-morbid intelligence (Spot-the-Word test from the Speed and Capacity of Language Processing). Separately, LC results were standardised relative to the population of test-takers, using a computer application designed specifically for this project.
Hierarchical regression analysis revealed that standardised LC performance F(2,48) = 3.90,
= 0.03 and Spot-the-Word F(2,47) = 5.88,
= 0.005 significantly predicted current intellect. Crawford & Allen's demographic-based regression formula did not. Furthermore, after controlling for gender, English F(1,49) = 11.27,
= 0.002 and Irish F(1,46) = 4.06,
= 0.049) results significantly predicted Vocabulary performance, while Mathematics results significantly predicted MR F(1,49) = 8.80,
= 0.005.
These results suggest that standardised LC performance may represent a useful resource for clinicians when estimating pre-morbid intelligence.
Amplified fragment length polymorphism (AFLP) fingerprint data are now commonly collected using DNA sequencers. AFLP genotypes are still often scored by eye from such data -- a time-consuming, ...error-prone and subjective process. We present a semi-automated method of genotyping sequencer-collected AFLPs at predefined fragment locations (loci) within the fingerprint. Our method uses thresholds of AFLP-polymerase chain reaction-product fluorescence intensity (peak height) in order to: (i) exclude AFLP loci that are likely to contribute high rates of error to data sets, and (ii) determine the AFLP phenotype (fragment presence or absence) at the retained loci. Error rate analysis is an integral part of this process and is used to determine optimal thresholds that minimize genotyping error, while maximizing the numbers of retained loci. We show that application of this method to a large AFLP data set allows genotype calls that are rapid, objective and repeatable, facilitating the extraction of reliable genotype data for molecular ecological studies.
Abstract The present study endeavored to calculate a conservative estimate of both incidence- and prevalence-based costs of nonepileptic attack disorder (NEAD) in Ireland by applying previously ...identified prevalence figures to Irish population figures. Variables related to the economic cost of NEAD were identified based on a retrospective chart review of patients diagnosed with NEAD at Beaumont Hospital, Dublin. The annual cost per patient of undiagnosed NEAD was calculated as €20,995.30. The combined cost of diagnosis and psychological treatment of NEAD was estimated at €8728. Although it is difficult to determine precise economic costings, early diagnosis and intervention would result in a significant economic saving to the exchequer, a reduction in hospital waiting-list times, and a better prognosis for patients.
Epigenetic control of gene expression is a consistent feature of differentiated mammalian cell types. Epigenetic expression patterns are mitotically heritable and are stably maintained in adult ...cells. However, unlike somatic DNA mutation, little is known about the occurrence of epigenetic change, or epimutation, during normal adult life. We have monitored the age-associated maintenance of two epigenetic systems--X inactivation and genomic imprinting--using the genes Atp7a and Igf2, respectively. Quantitative measurements of RNA transcripts from the inactive and active alleles were performed in mice from 2 to 24 months of age. For both genes, older animal cohorts showed reproducible increases in transcripts expressed from the silenced alleles. Loss of X chromosome silencing showed cohort mean increases of up to 2.2%, while imprinted-gene activation increased up to 6.7%. The results support the hypothesis that epigenetic loss of gene repression occurs in normal tissues and may be a contributing factor in progressive physiological dysfunction seen during mammalian aging. Quantitatively, the loss of epigenetic control may be one to two orders of magnitude greater than previously determined somatic DNA mutation.
Repeatability of parental care, let alone heritability of care, has been rarely measured, although there has been much research linking sexual selection to male parental care and also examining ...biparental care in relation to game theory models. We investigated within‐ and between‐year repeatabilities of incubation and nestling provisioning and how these two types of parental care were related in a sexually dimorphic species, the house sparrow, Passer domesticus. We found that between‐ and within‐year repeatabilities of feeding rate were high in males and low to moderate in females, but that between‐ and within‐year repeatabilities of incubation time were low to moderate in both sexes. Interestingly, the amount of time during which neither sex incubated significantly predicted the subsequent male feeding rate but not the female feeding rate. Our results suggest a need for a new theoretical framework that encompasses variation in the predictability and plasticity of parental investment by individuals.
The purpose of this study was to evaluate the utility of transcatheter thrombolytic therapy in 20 patients with acute or subacute (symptoms <40 days) portal and/or mesenteric vein thrombosis with ...severe symptoms, deteriorating clinical condition, and/or persistent symptoms despite anticoagulation.
This retrospective study examined 12 male patients and eight female patients seen over a period of 11 years. The average age was 37.6 years. Four of the patients had previously undergone liver transplantation. An anatomic classification system was established to describe the extent of thrombus at the time of diagnosis. Patients were treated with thrombolytic therapy via the transhepatic route, common femoral vein route, and/or superior mesenteric artery route. Improvement in symptoms, avoidance of bowel resection, complications, and radiographic evidence of clot resolution were the main clinical outcomes.
Fifteen of the 20 patients exhibited some degree of lysis of the thrombus. Three patients had complete resolution, 12 had partial resolution, and five had no resolution. Eighty-five percent of patients (n = 17) had resolution of symptoms. Sixty percent of patients (n = 12) developed a major complication. No patients required bowel resection after thrombolytic therapy. One patient died with gastrointestinal hemorrhage and septic shock 2 weeks after thrombolytic therapy. Other major complications included bleeding and conditions requiring transfusion. No patients developed new portal or mesenteric thromboses. Two of the patients who received transplants eventually required repeat transplantation.
Transcatheter thrombolysis was beneficial in avoiding patient death, resolving thrombus, improving symptoms, and avoiding bowel resection. However, there was a high complication rate, indicating that this therapy should be reserved for patients with severe disease. Further evaluation of these techniques and outcomes should continue to be pursued.
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