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1.
Glob Chang Biol ; 30(1): e17013, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37994377

RESUMO

Lakes worldwide are affected by multiple stressors, including climate change. This includes massive loading of both nutrients and humic substances to lakes during extreme weather events, which also may disrupt thermal stratification. Since multi-stressor effects vary widely in space and time, their combined ecological impacts remain difficult to predict. Therefore, we combined two consecutive large enclosure experiments with a comprehensive time-series and a broad-scale field survey to unravel the combined effects of storm-induced lake browning, nutrient enrichment and deep mixing on phytoplankton communities, focusing particularly on potentially toxic cyanobacterial blooms. The experimental results revealed that browning counteracted the stimulating effect of nutrients on phytoplankton and caused a shift from phototrophic cyanobacteria and chlorophytes to mixotrophic cryptophytes. Light limitation by browning was identified as the likely mechanism underlying this response. Deep-mixing increased microcystin concentrations in clear nutrient-enriched enclosures, caused by upwelling of a metalimnetic Planktothrix rubescens population. Monitoring data from a 25-year time-series of a eutrophic lake and from 588 northern European lakes corroborate the experimental results: Browning suppresses cyanobacteria in terms of both biovolume and proportion of the total phytoplankton biovolume. Both the experimental and observational results indicated a lower total phosphorus threshold for cyanobacterial bloom development in clearwater lakes (10-20 µg P L-1 ) than in humic lakes (20-30 µg P L-1 ). This finding provides management guidance for lakes receiving more nutrients and humic substances due to more frequent extreme weather events.


Assuntos
Cianobactérias , Fitoplâncton , Lagos/microbiologia , Substâncias Húmicas , Eutrofização , Nutrientes , Fósforo/análise , China
2.
J Asthma Allergy ; 15: 1217-1226, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36071746

RESUMO

Purpose: Ailanthus altissima is one of the world's most invasive species with a globally problematic spread. Pollen is dispersed locally and partially airborne. We aimed at investigating if (i) A. altissima pollen can be detected in relevant quantity in the air and if (ii) sensitization to A. altissima can be detected in patients with seasonal exacerbation of atopic diseases. Patients and Methods: We recorded distribution of A. altissima in Leipzig, Germany. In 2019 and 2020, pollen was collected with a Hirst-type pollen trap placed on the roof of the University Hospital. Specific IgE investigations were performed in children and adults with history of atopic diseases with deterioration between May and July. We analysed specific IgE for A. altissima, Alternaria sp., birch, grasses, profilins, polcalcins and crossreacting carbohydrates. Results: We found abundant growth of A. altissima and pollen was detected from early June to mid-July with a maximum pollen concentration of 31 pollen/m3. Out of 138 patients (63 female, 69 children/adolescents), 95 (69%) had seasonal allergic rhinitis, 84 (61%) asthma, and 43 (31%) atopic dermatitis. Sensitization to A. altissima was shown in 59 (42%). There were no significant differences between age groups. In 59% of patients sensitized (35/59), there was no sensitization to possibly cross-reacting structures. Conclusion: Sensitization to A. altissima pollen could be detected in 42% of our patients with atopic diseases, suggesting allergenic potential of this neophyte. In the context of further spread with climate change, eradication strategies and population-based sensitization studies are needed.

3.
Cytometry A ; 101(9): 782-799, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35670307

RESUMO

Environmental monitoring involves the quantification of microscopic cells and particles such as algae, plant cells, pollen, or fungal spores. Traditional methods using conventional microscopy require expert knowledge, are time-intensive and not well-suited for automated high throughput. Multispectral imaging flow cytometry (MIFC) allows measurement of up to 5000 particles per second from a fluid suspension and can simultaneously capture up to 12 images of every single particle for brightfield and different spectral ranges, with up to 60x magnification. The high throughput of MIFC has high potential for increasing the amount and accuracy of environmental monitoring, such as for plant-pollinator interactions, fossil samples, air, water or food quality that currently rely on manual microscopic methods. Automated recognition of particles and cells is also possible, when MIFC is combined with deep-learning computational techniques. Furthermore, various fluorescence dyes can be used to stain specific parts of the cell to highlight physiological and chemical features including: vitality of pollen or algae, allergen content of individual pollen, surface chemical composition (carbohydrate coating) of cells, DNA- or enzyme-activity staining. Here, we outline the great potential for MIFC in environmental research for a variety of research fields and focal organisms. In addition, we provide best practice recommendations.


Assuntos
Monitoramento Ambiental , Microscopia , Alérgenos , Citometria de Fluxo/métodos , Coloração e Rotulagem
4.
Sci Total Environ ; 755(Pt 1): 142881, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33097263

RESUMO

The SARS-CoV-2 pandemic co-occurred with pollen season in Europe 2020 and recent studies suggest a potential link between both. Air samples collected at our measuring station in Leipzig and purified pollen were analyzed for SARS-CoV-2 typical signals or for virus-induced cytopathic effects, to test if the virus could bind to bioaerosols and if so, whether these complexes are infectious. The results show that neither our air samples nor purified pollen were infectious or could act as carrier for virus particles.


Assuntos
COVID-19 , Material Particulado , Europa (Continente) , Humanos , Material Particulado/análise , Pólen/química , SARS-CoV-2
5.
New Phytol ; 229(1): 593-606, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32803754

RESUMO

Pollen identification and quantification are crucial but challenging tasks in addressing a variety of evolutionary and ecological questions (pollination, paleobotany), but also for other fields of research (e.g. allergology, honey analysis or forensics). Researchers are exploring alternative methods to automate these tasks but, for several reasons, manual microscopy is still the gold standard. In this study, we present a new method for pollen analysis using multispectral imaging flow cytometry in combination with deep learning. We demonstrate that our method allows fast measurement while delivering high accuracy pollen identification. A dataset of 426 876 images depicting pollen from 35 plant species was used to train a convolutional neural network classifier. We found the best-performing classifier to yield a species-averaged accuracy of 96%. Even species that are difficult to differentiate using microscopy could be clearly separated. Our approach also allows a detailed determination of morphological pollen traits, such as size, symmetry or structure. Our phylogenetic analyses suggest phylogenetic conservatism in some of these traits. Given a comprehensive pollen reference database, we provide a powerful tool to be used in any pollen study with a need for rapid and accurate species identification, pollen grain quantification and trait extraction of recent pollen.


Assuntos
Aprendizado Profundo , Citometria de Fluxo , Filogenia , Pólen , Polinização
6.
Innov Aging ; 3(3): igz031, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31660442

RESUMO

BACKGROUND AND OBJECTIVES: Numerous non-pharmacological programs for family caregivers and persons with dementia (PWDs) have been found efficacious in randomized controlled trials. Few programs have been tested in translation studies that assess feasibility and outcomes in less-controlled, real-world implementations. This translation study tested the impact of the partnership version of BRI Care Consultation, "Partners in Dementia Care (PDC)," on outcomes for PWDs and their family/friend caregivers. PDC was delivered via partnerships between the Louis Stokes Department of Veterans Affairs Medical Center and the Greater East Ohio Alzheimer's Association Chapter and the Western Reserve Area Agency on Aging. PDC is a personalized coaching program done by telephone, e-mail, and regular mail. RESEARCH DESIGN AND METHODS: For this translation study, the program was implemented in a manner that mirrored a non-research implementation. The study sample included 148 caregivers and 84 PWDs who used PDC for 12 months. Research data came from 2 structured telephone interviews, one before program implementation and a follow-up after program completion. PWDs and caregivers averaged 14 telephone contacts with Care Consultants over the 12-month study period, and 12 behavioral action steps to address problems or concerns. RESULTS: Repeated measures ANOVAs showed the use of PDC was related to significant improvements across several outcomes for PWDs and caregivers, with greater benefits in more difficult caregiving situations. Caregivers had decreased levels of isolation, physical health strain, unmet needs; and increased confidence in caregiving capacity, informal helpers, and support service use. PWDs had decreased embarrassment about memory problems and unmet needs; and increased informal support and community service use. DISCUSSION AND IMPLICATIONS: Overall, improved outcomes for PWDs and caregivers in this translation study were similar to findings from previous randomized trials, and affirmed the value of the program when delivered as a regular service offering by health care and community service organizations.

7.
Environ Microbiol ; 21(1): 34-49, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30246449

RESUMO

Non-predatory mortality of zooplankton provides an abundant, yet, little studied source of high quality labile organic matter (LOM) in aquatic ecosystems. Using laboratory microcosms, we followed the decomposition of organic carbon of fresh 13 C-labelled Daphnia carcasses by natural bacterioplankton. The experimental setup comprised blank microcosms, that is, artificial lake water without any organic matter additions (B), and microcosms either amended with natural humic matter (H), fresh Daphnia carcasses (D) or both, that is, humic matter and Daphnia carcasses (HD). Most of the carcass carbon was consumed and respired by the bacterial community within 15 days of incubation. A shift in the bacterial community composition shaped by labile carcass carbon and by humic matter was observed. Nevertheless, we did not observe a quantitative change in humic matter degradation by heterotrophic bacteria in the presence of LOM derived from carcasses. However, carcasses were the main factor driving the bacterial community composition suggesting that the presence of large quantities of dead zooplankton might affect the carbon cycling in aquatic ecosystems. Our results imply that organic matter derived from zooplankton carcasses is efficiently remineralized by a highly specific bacterial community, but does not interfere with the bacterial turnover of more refractory humic matter.


Assuntos
Bactérias/metabolismo , Ciclo do Carbono , Daphnia/química , Água Doce/microbiologia , Zooplâncton/química , Animais , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Carbono/metabolismo , Daphnia/metabolismo , Daphnia/microbiologia , Ecossistema , Processos Heterotróficos , Zooplâncton/metabolismo , Zooplâncton/microbiologia
8.
PLoS One ; 12(11): e0188198, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29190760

RESUMO

The oceans absorb ~25% of the annual anthropogenic CO2 emissions. This causes a shift in the marine carbonate chemistry termed ocean acidification (OA). OA is expected to influence metabolic processes in phytoplankton species but it is unclear how the combination of individual physiological changes alters the structure of entire phytoplankton communities. To investigate this, we deployed ten pelagic mesocosms (volume ~50 m3) for 113 days at the west coast of Sweden and simulated OA (pCO2 = 760 µatm) in five of them while the other five served as controls (380 µatm). We found: (1) Bulk chlorophyll a concentration and 10 out of 16 investigated phytoplankton groups were significantly and mostly positively affected by elevated CO2 concentrations. However, CO2 effects on abundance or biomass were generally subtle and present only during certain succession stages. (2) Some of the CO2-affected phytoplankton groups seemed to respond directly to altered carbonate chemistry (e.g. diatoms) while others (e.g. Synechococcus) were more likely to be indirectly affected through CO2 sensitive competitors or grazers. (3) Picoeukaryotic phytoplankton (0.2-2 µm) showed the clearest and relatively strong positive CO2 responses during several succession stages. We attribute this not only to a CO2 fertilization of their photosynthetic apparatus but also to an increased nutrient competitiveness under acidified (i.e. low pH) conditions. The stimulating influence of high CO2/low pH on picoeukaryote abundance observed in this experiment is strikingly consistent with results from previous studies, suggesting that picoeukaryotes are among the winners in a future ocean.


Assuntos
Concentração de Íons de Hidrogênio , Oceanos e Mares , Fitoplâncton/metabolismo , Biomassa
9.
Clin Vaccine Immunol ; 24(3)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28100496

RESUMO

Both preexisting immunity to influenza and age have been shown to be correlates of influenza vaccine responses. Frailty, an indicator of functional impairment in older adults, was also shown in one study to predict lower influenza vaccine responses among nonveterans. In the current study, we aimed to determine the associations between frailty, preexisting immunity, and immune responses to influenza vaccine among older veterans. We studied 117 subjects (age range, 62 to 95 years [median age, 81 years]), divided into three cohorts based on the Fried frailty test, i.e., nonfrail (NF) (n = 23 [median age, 68 years]), prefrail (n = 50 [median age, 80 years]), and frail (n = 44 [median age, 82 years]), during the 2010-2011 and 2011-2012 influenza seasons. Subjects received the seasonal trivalent inactivated influenza vaccine, and baseline and postvaccination samples were obtained. Anti-influenza humoral immunity, as measured by hemagglutination inhibition (HI) and microneutralization assays, was measured for influenza B, A(H1N1)pdm09, and A(H3N2) viruses. Postvaccination titers were not different between frail and NF subjects overall in this older subset of veterans. However, preexisting HI titers were strongly correlated with postvaccination titers among all functional status groups. When microneutralization titers were compared, the association between preexisting immunity and vaccine responses varied by frailty status, with the strongest correlation being observed for the NF group. In conclusion, preexisting immunity rather than frailty appeared to predict postvaccination titers in this older veteran cohort.


Assuntos
Anticorpos Antivirais/sangue , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/administração & dosagem , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Veteranos
10.
PLoS One ; 11(8): e0159068, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27525979

RESUMO

Every year, the oceans absorb about 30% of anthropogenic carbon dioxide (CO2) leading to a re-equilibration of the marine carbonate system and decreasing seawater pH. Today, there is increasing awareness that these changes-summarized by the term ocean acidification (OA)-could differentially affect the competitive ability of marine organisms, thereby provoking a restructuring of marine ecosystems and biogeochemical element cycles. In winter 2013, we deployed ten pelagic mesocosms in the Gullmar Fjord at the Swedish west coast in order to study the effect of OA on plankton ecology and biogeochemistry under close to natural conditions. Five of the ten mesocosms were left unperturbed and served as controls (~380 µatm pCO2), whereas the others were enriched with CO2-saturated water to simulate realistic end-of-the-century carbonate chemistry conditions (~760 µatm pCO2). We ran the experiment for 113 days which allowed us to study the influence of high CO2 on an entire winter-to-summer plankton succession and to investigate the potential of some plankton organisms for evolutionary adaptation to OA in their natural environment. This paper is the first in a PLOS collection and provides a detailed overview on the experimental design, important events, and the key complexities of such a "long-term mesocosm" approach. Furthermore, we analyzed whether simulated end-of-the-century carbonate chemistry conditions could lead to a significant restructuring of the plankton community in the course of the succession. At the level of detail analyzed in this overview paper we found that CO2-induced differences in plankton community composition were non-detectable during most of the succession except for a period where a phytoplankton bloom was fueled by remineralized nutrients. These results indicate: (1) Long-term studies with pelagic ecosystems are necessary to uncover OA-sensitive stages of succession. (2) Plankton communities fueled by regenerated nutrients may be more responsive to changing carbonate chemistry than those having access to high inorganic nutrient concentrations and may deserve particular attention in future studies.


Assuntos
Plâncton/metabolismo , Estações do Ano , Água do Mar/química , Dióxido de Carbono/química , Concentração de Íons de Hidrogênio , Plâncton/crescimento & desenvolvimento
11.
Sleep Health ; 1(4): 322-330, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27066526

RESUMO

OBJECTIVES: Light therapy has shown promise as a nonpharmacological treatment to help regulate abnormal sleep-wake patterns and associated behavioral issues prevalent among individuals diagnosed with Alzheimer's disease and related dementia (ADRD). The present study investigated the effectiveness of a lighting intervention designed to increase circadian stimulation during the day using light sources that have high short-wavelength content and high light output. METHODS: Thirty-five persons with ADRD and 34 caregivers completed the 11-week study. During week 1, subjective questionnaires were administered to the study participants. During week 2, baseline data were collected using Daysimeters and actigraphs. Researchers installed the lighting during week 3, followed by 4 weeks of the tailored lighting intervention. During the last week of the lighting intervention, Daysimeter, actigraph and questionnaire data were again collected. Three weeks after the lighting intervention was removed, a third data collection (post-intervention assessment) was performed. RESULTS: The lighting intervention significantly increased circadian entrainment, as measured by phasor magnitude and sleep efficiency, as measured by actigraphy data, and significantly reduced symptoms of depression in the participants with ADRD. The caregivers also exhibited an increase in circadian entrainment during the lighting intervention; a seasonal effect of greater sleep efficiency and longer sleep duration was also found for caregivers. CONCLUSIONS: An ambient lighting intervention designed to increase daytime circadian stimulation can be used to increase sleep efficiency in persons with ADRD and their caregivers, and may also be effective for other populations such as healthy older adults with sleep problems, adolescents, and veterans with traumatic brain injury.

12.
Fed Pract ; 32(2): 42-45, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30766046

RESUMO

Although research has yet to provide a definitive answer about whether circadian-active light can benefit patients with dementia, a VA pilot study shows promising results.

13.
Clin Interv Aging ; 9: 1527-37, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25246779

RESUMO

BACKGROUND: Light therapy has shown great promise as a nonpharmacological method to improve symptoms associated with Alzheimer's disease and related dementias (ADRD), with preliminary studies demonstrating that appropriately timed light exposure can improve nighttime sleep efficiency, reduce nocturnal wandering, and alleviate evening agitation. Since the human circadian system is maximally sensitive to short-wavelength (blue) light, lower, more targeted lighting interventions for therapeutic purposes, can be used. METHODS: The present study investigated the effectiveness of a tailored lighting intervention for individuals with ADRD living in nursing homes. Low-level "bluish-white" lighting designed to deliver high circadian stimulation during the daytime was installed in 14 nursing home resident rooms for a period of 4 weeks. Light-dark and rest-activity patterns were collected using a Daysimeter. Sleep time and sleep efficiency measures were obtained using the rest-activity data. Measures of sleep quality, depression, and agitation were collected using standardized questionnaires, at baseline, at the end of the 4-week lighting intervention, and 4 weeks after the lighting intervention was removed. RESULTS: The lighting intervention significantly (P<0.05) decreased global sleep scores from the Pittsburgh Sleep Quality Index, and increased total sleep time and sleep efficiency. The lighting intervention also increased phasor magnitude, a measure of the 24-hour resonance between light-dark and rest-activity patterns, suggesting an increase in circadian entrainment. The lighting intervention significantly (P<0.05) reduced depression scores from the Cornell Scale for Depression in Dementia and agitation scores from the Cohen-Mansfield Agitation Inventory. CONCLUSION: A lighting intervention, tailored to increase daytime circadian stimulation, can be used to increase sleep quality and improve behavior in patients with ADRD. The present field study, while promising for application, should be replicated using a larger sample size and perhaps using longer treatment duration.


Assuntos
Ritmo Circadiano/efeitos da radiação , Demência/complicações , Depressão/prevenção & controle , Fototerapia , Agitação Psicomotora/prevenção & controle , Transtornos do Sono-Vigília/prevenção & controle , Atividades Cotidianas , Idoso de 80 Anos ou mais , Doença de Alzheimer/complicações , Feminino , Humanos , Masculino , Entrevista Psiquiátrica Padronizada , Casas de Saúde , Inquéritos e Questionários , Resultado do Tratamento
14.
J Adv Nurs ; 70(5): 1164-73, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24164506

RESUMO

AIMS: To describe light exposure, sleep-wake patterns, mood, pain and their relationships in adult medical inpatients. BACKGROUND: The hospital environment may contribute to patient discomfort by providing a lighting structure that interferes with circadian rhythmicity, sleep, mood and pain. DESIGN: A descriptive correlational design was used in this preliminary study. METHODS: Between May 2011-April 2012, data were collected from a convenience sample of 23 women and 17 men admitted to a large academically affiliated hospital in the United States. Over 72 hours, light exposure and sleep-wake patterns were continuously measured with wrist actigraph/light meters for each participant. Mood was measured daily using the Profile Of Mood States Brief™ Form. Subjective pain scores were abstracted from medical records. RESULTS: Light exposure levels were low: mean daytime light intensity was 104·80 lux. Sleep time was fragmented and low: mean 236·35 minutes of sleep/night. Intra-daily stability scores indicated little sleep-wake synchronization with light. Fatigue and total mood disturbance scores were high and inversely associated with light. Pain levels were also high and positively associated with fatigue, but not directly with light exposure. Low light exposure significantly predicted fatigue and total mood disturbance. CONCLUSION: Medical inpatients were exposed to light levels insufficient for circadian entrainment. Nevertheless, higher light exposure was associated with less fatigue and lower total mood disturbance in participants with pain, suggesting the need for further investigation to determine if manipulating light exposure for medical inpatients would be beneficial in affecting sleep-wake disturbances, mood and pain.


Assuntos
Afeto , Pacientes Internados , Iluminação , Serviço Hospitalar de Engenharia e Manutenção , Dor , Sono , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
15.
Geriatr Gerontol Int ; 14(1): 78-83, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23530477

RESUMO

AIM: Frailty is a common phenomenon in geriatric patients. In the present translational research study, we assessed two frailty instruments (Fried 2001; Gill 2002), comparing the usefulness and scoring classifications for frailty screening in an academically affiliated geriatrics clinic. METHODS: Assessment was completed on 162 male veterans (mean age 83.7 years, 57% African American) enrolled in a geriatric clinic. The instruments' component criteria, which are well known to gerontological clinicians, were administered in a standard order and scoring was identical to original instruments. RESULTS: The five-item Fried frailty instrument required 15-20 min to complete; the two-item Gill frailty instrument required less than 2 min. Of the 162 participants assessed, 72 were determined to be frail by at least one of the instruments, but just 33 were frail by both instruments. Correlations between the instruments were Spearman = 0.55 (P < 0.001) and kappa = 0.25, (P < 0.001). There were no differences in frailty scores based on race, and there were equivocal results based on age, even though this was an older sample, with almost 17% ≥90 years. A total of 63% (103/162) of the sample met the criterion for weak grip strength, and decreasing grip strength correlated with increasing age (r = -0.238, P = 0.002). CONCLUSION: Expedient identification of the frailty syndrome remains an unmet necessity for clinical practice. The different results by the Fried and Gill frailty instruments are likely due to differences in component domains and testing methods. The present results support previous findings that showed that grip strength might be an important indicator of increasing frailty.


Assuntos
Instituições de Assistência Ambulatorial , Idoso Fragilizado , Avaliação Geriátrica/métodos , Serviços de Saúde para Idosos , Atividade Motora/fisiologia , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Perfil de Impacto da Doença , Estados Unidos
16.
Ecology ; 94(12): 2754-66, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24597222

RESUMO

In aquatic systems, terrestrial dissolved organic matter (t-DOM) is known to stimulate bacterial activities in the water column, but simultaneous effects of autumnal leaf input on water column and sediment microbial dynamics in littoral zones of lakes remain largely unknown. The study's objective was to determine the effects of leaf litter on bacterial metabolism in the littoral water and sediment, and subsequently, the consequences for carbon cycling and food web dynamics. Therefore, in late fall, we simultaneously measured water and sediment bacterial metabolism in the littoral zone of a temperate shallow lake after adding terrestrial particulate organic matter (t-POM), namely, maize leaves. To better evaluate bacterial production (BP) and community respiration (CR) in sediments, we incubated sediment cores with maize leaves of different quality (nonleached and leached) under controlled laboratory conditions. Additionally, to quantify the incorporated leaf carbon into microbial biomass, we determined carbon isotopic ratios of fatty acids from sediment and leaf-associated microbes from a laboratory experiment using 13C-enriched beech leaves. The concentrations of dissolved organic carbon (DOC) increased significantly in the lake after the addition of maize leaves, accompanied by a significant increase in water BP. In contrast, sediment BP declined after an initial peak, showing no positive response to t-POM addition. Sediment BP and CR were also not stimulated by t-POM in the laboratory experiment, either in short-term or in long-term incubations, except for a short increase in CR after 18 hours. However, this increase might have reflected the metabolism of leaf-associated microorganisms. We conclude that the leached t-DOM is actively incorporated into microbial biomass in the water column but that the settling leached t-POM (t-POML) does not enter the food web via sediment bacteria. Consequently, t-POML is either buried in the sediment or introduced into the aquatic food web via microorganisms (bacteria and fungi) directly associated with t-POM(L) and via benthic macroinvertebrates by shredding of t-POM(L). The latter pathway represents a "benthic shortcut" which efficiently transfers t-POM(L) to higher trophic levels.


Assuntos
Bactérias/metabolismo , Carbono/química , Carbono/metabolismo , Ecossistema , Ciclo do Carbono , Sedimentos Geológicos/microbiologia , Microbiologia da Água
17.
J Alzheimers Dis ; 31(4): 711-5, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22699845

RESUMO

The absence of daily robust light-dark exposure patterns may contribute to sleep disturbances in persons with Alzheimer's disease and related dementias (ADRD). Personal light-dark and activity-rest patterns were measured for healthy older adults and for persons with ADRD. Persons with ADRD experienced lower light levels, exhibited lower activity levels, and had greater levels of circadian disruption than healthy older adults during winter. Seasonal differences were observed for persons with ADRD; lower levels of light exposure and greater levels of circadian disruption were seen during the winter than during the summer, although activity levels did not differ for the two seasons.


Assuntos
Ritmo Circadiano/fisiologia , Demência/psicologia , Fotoperíodo , Vigilância da População/métodos , Estações do Ano , Luz Solar , Idoso , Doença de Alzheimer/complicações , Doença de Alzheimer/psicologia , Doença de Alzheimer/terapia , Demência/complicações , Demência/terapia , Feminino , Humanos , Luz , Masculino , Transtornos do Sono-Vigília/etiologia , Transtornos do Sono-Vigília/prevenção & controle
18.
Am J Alzheimers Dis Other Demen ; 25(4): 353-61, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20237336

RESUMO

BACKGROUND: This methodological case study describes light exposure and rest-activity patterns in an older adult with dementia and his caregiver spouse. METHODS: Two devices were used to measure rest-activity and light exposure data: a wrist-worn actigraph with a light sensor to record full spectrum light exposure data and an eye-level wavelength-sensitive light meter (Daysimeter). The wife wore both devices simultaneously; the husband wore only the actigraph. RESULTS: There were minimal feasibility issues in using the devices in the home setting. The wife's light exposure was considerably better than her husband's, but she spent little time in bright lighting. Her circadian stimulus (CS) and rest-activity values suggest a high level of circadian disruption. CONCLUSION: This case study provides beginning support for the use of the Daysimeter in the home setting while also highlighting unrecognized circadian disturbances and very low light levels in an older couple's home.


Assuntos
Demência , Luz , Transtornos do Sono do Ritmo Circadiano/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Cuidadores , Ritmo Circadiano , Demência/complicações , Feminino , Humanos , Masculino , Ohio , Transtornos do Sono do Ritmo Circadiano/complicações
19.
J Clin Immunol ; 30(3): 373-83, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20182777

RESUMO

BACKGROUND: The majority of deaths (90%) attributed to influenza are in person's age 65 or older. Little is known about whether defects in innate immune responses in geriatric individuals contribute to their susceptibility to influenza. OBJECTIVE: Our aim was to analyze interferon-alpha (IFN-alpha) production in peripheral blood mononuclear cells (PBMCs) isolated from young and geriatric adult donors, stimulated with influenza A or Toll-like receptor (TLR) ligands. IFN-alpha is a signature anti-viral cytokine that also shapes humoral and cell-mediated immune responses. RESULTS: Geriatric PBMCs produced significantly less IFN-alpha in response to live or inactivated influenza (a TLR7 ligand) but responded normally to CpG ODN (TLR9 ligand) and Guardiquimod (TLR7 ligand). All three ligands activate plasmacytoid dendritic cells (pDCs). While there was a modest decline in pDC frequency in older individuals, there was no defect in uptake of influenza by geriatric pDCs. DISCUSSION AND CONCLUSION: Influenza-induced production of IFN-alpha was defective in geriatric PBMCs by a mechanism that was independent of reduced pDC frequency or viability, defects in uptake of influenza, inability to secrete IFN-alpha, or defects in TLR7 signaling.


Assuntos
Fatores Etários , Células Dendríticas/metabolismo , Influenza Humana/imunologia , Interferon-alfa/metabolismo , Orthomyxoviridae/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Dendríticas/imunologia , Células Dendríticas/patologia , Células Dendríticas/virologia , Suscetibilidade a Doenças , Feminino , Humanos , Imunidade Inata , Influenza Humana/epidemiologia , Influenza Humana/patologia , Interferon-alfa/genética , Interferon-alfa/imunologia , Ligantes , Masculino , Orthomyxoviridae/patogenicidade , Receptores Toll-Like/imunologia
20.
J Med Case Rep ; 2: 300, 2008 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-18783609

RESUMO

INTRODUCTION: Metformin is a widely prescribed biguanide antidiabetic drug that has been implicated as a cause of hemolytic anemia in three previous case reports. We report a case of rapidly fatal hemolysis that was temporally associated with the initiation of metformin treatment for diabetes. Clinicians need to be aware of this rare but potentially serious side effect of metformin. CASE PRESENTATION: A 56-year-old Caucasian man with type 2 diabetes mellitus was started on metformin to improve glycemic control. Shortly afterwards, he developed progressive fatigue, exertional dyspnea, cranberry-colored urine and jaundice. Laboratory studies showed severe hemolysis, with a drop in hemoglobin from 14.7 to 6.6 g/dl over 4 days, markedly elevated lactate dehydrogenase, bilirubin and reticulocyte counts, and a low haptoglobin level. A peripheral blood smear showed no schistocytes, and a direct Coombs test was positive for anti-IgG and negative for anti-C3. Despite corticosteroid treatment and transfusion of packed red blood cells, the patient developed increasing dyspnea, hypotension, further decline in hemoglobin to 3.3 g/dl, and fatal cardiorespiratory arrest 12 hours after admission. CONCLUSION: The serologic findings in this case suggest an autoimmune hemolytic anemia, caused either by a drug-induced autoantibody or a warm autoantibody. Based on the temporal association with metformin and the lack of other clear precipitating causes, we propose that metformin-induced hemolysis with a drug-induced autoantibody is a strong possibility. This mechanism differs from a previously described case with a possible antibody to the erythrocyte-drug complex. It has been shown, however, that hemolysis may occur via multiple mechanisms from the same drug. Clinicians should consider the possibility of metformin-associated immune hemolytic anemia in patients with otherwise unexplained hemolysis.

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