795 research outputs found
PGI10 EXAMINATION OF RESOURCE UTILIZATION PATTERNS ACROSS SUBGROUPS OF GASTROESOPHAGEAL REFLUX DISEASE PATIENTS
Efficacy of some essential oils in mice infected with Trypanosoma cruzi
Purpose: To evaluate the efficacy of orally administered Cymbopogon citratus, Zingiber officinale and Syzygium aromaticum essential oils (EOs) in mice infected with Trypanosoma cruzi.Methods: Three experiments were conducted with 48 Swiss mice each. The animals were inoculated with 2 x 106 metacyclic trypomastigotes of T. Cruzi Y-strain and allocated into the following groups (N = 12): 1) untreated control; 2) treated with benznidazole (BZ); 3) treated with EO 100 mg/kg; and 4) treated with EO 250 mg/kg. The groups were evaluated by fresh blood test, blood culture, conventional polymerase chain reaction (PCR), real-time PCR and cure rate (CR).Results: All the animals were completely infected with T. cruzi. Treatment with C. citratus and Z. officinale EOs altered some of the parameters derived from the parasitemia curve, but CRs did not differ from BZ. Treatment with S. Aromaticum EO, on the other hand, not only altered all the parameters derived from the parasitemia curve, similar to BZ, but at the dose of 100 mg/kg, CR was also significantly higher than BZ.Conclusion: The results indicate that the essential oils tested, especially S. aromaticum, exhibited anti- Trypanosoma cruzi effect and therefore should be investigated for the treatment of Chagas disease.Keywords: Chagas disease, Trypanosoma cruzi, Cymbopogon citratus, Zingiber officinale, Syzygium aromaticum, Essential oils, Chemotherap
MGMT enrichment and second gene co-expression in hematopoietic progenitor cells using separate or dual-gene lentiviral vectors
AbstractThe DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) allows efficient in vivo enrichment of transduced hematopoietic stem cells (HSC). Thus, linking this selection strategy to therapeutic gene expression offers the potential to reconstitute diseased hematopoietic tissue with gene-corrected cells. However, different dual-gene expression vector strategies are limited by poor expression of one or both transgenes. To evaluate different co-expression strategies in the context of MGMT-mediated HSC enrichment, we compared selection and expression efficacies in cells cotransduced with separate single-gene MGMT and GFP lentivectors to those obtained with dual-gene vectors employing either encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) or foot and mouth disease virus (FMDV) 2A elements for co-expression strategies. Each strategy was evaluated in vitro and in vivo using equivalent multiplicities of infection (MOI) to transduce 5-fluorouracil (5-FU) or Lin−Sca-1+c-kit+ (LSK)-enriched murine bone marrow cells (BMCs). The highest dual-gene expression (MGMT+GFP+) percentages were obtained with the FMDV-2A dual-gene vector, but half of the resulting gene products existed as fusion proteins. Following selection, dual-gene expression percentages in single-gene vector cotransduced and dual-gene vector transduced populations were similar. Equivalent MGMT expression levels were obtained with each strategy, but GFP expression levels derived from the IRES dual-gene vector were significantly lower. In mice, vector-insertion averages were similar among cells enriched after dual-gene vectors and those cotransduced with single-gene vectors. These data demonstrate the limitations and advantages of each strategy in the context of MGMT-mediated selection, and may provide insights into vector design with respect to a particular therapeutic gene or hematologic defect
The association between physical activity and mental health during the first year of the COVID-19 pandemic: a systematic review
© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.Introduction: The Coronavirus disease-19 (COVID-19) pandemic affected countries worldwide and has changed peoples' lives. A reduction in physical activity and increased mental health problems were observed, mainly in the first year of the COVID-19 pandemic. Thus, this systematic review aims to examine the association between physical activity and mental health during the first year of the COVID-19 pandemic.
Methods: In July 2021, a search was applied to PubMed, Scopus, and Web of Science. Eligibility criteria included cross-sectional, prospective, and longitudinal study designs and studies published in English; outcomes included physical activity and mental health (e.g., depressive symptoms, anxiety, positive and negative effects, well-being).
Results: Thirty-one studies were included in this review. Overall, the studies suggested that higher physical activity is associated with higher well-being, quality of life as well as lower depressive symptoms, anxiety, and stress, independently of age. There was no consensus for the optimal physical activity level for mitigating negative mental symptoms, neither for the frequency nor for the type of physical activity. Women were more vulnerable to mental health changes and men were more susceptive to physical activity changes.
Conclusion: Physical activity has been a good and effective choice to mitigate the negative effects of the COVID-19 pandemic on mental health during the first year of the COVID-19 pandemic. Public health policies should alert for possibilities to increase physical activity during the stay-at-home order in many countries worldwide.AI acknowledges support from the Swiss National Centre of Competence in Research LIVES – Overcoming vulnerability: life course perspectives, granted by the Swiss National Science Foundation (grant number: 51NF40-185901). AI acknowledges support from the Swiss National Science Foundation (grant number: 10001C_189407). André Werneck is supported by the São Paulo Research Foundation (FAPESP) with a PhD scholarship (FAPESP process: 2019/24124-7).info:eu-repo/semantics/publishedVersio
Thermoregulation in desert birds : scaling and phylogenetic variation in heat tolerance and evaporative cooling
Evaporative heat dissipation is a key aspect of avian thermoregulation
in hot environments.We quantified variation in avian thermoregulatory
performance at high air temperatures (Ta) using published data on
body temperature (Tb), evaporative water loss (EWL) and resting
metabolic rate (RMR) measured under standardized conditions of very
low humidity in 56 arid-zone species. Maximum Tb during acute heat
exposure varied from 42.5±1.3°C in caprimulgids to 44.5±0.5°C in
passerines. Among passerines, both maximum Tb and the difference
between maximum and normothermic Tb decreased significantly with
body mass (Mb). Scaling exponents for minimum thermoneutral EWL
and maximum EWL were 0.825 and 0.801, respectively, even though
evaporative scope (ratio of maximum to minimum EWL) varied widely
among species. Upper critical limits of thermoneutrality (Tuc) varied by
>20°C and maximumRMR during acute heat exposure scaled toMb
0.75
in both the overall data set and among passerines. The slope of RMR
at Ta>Tuc increased significantly with Mb but was substantially higher
among passerines, which rely on panting, comparedwith columbids, in
which cutaneous evaporation predominates. Our analysis supports
recent arguments that interspecific within-taxon variation in heat
tolerance is functionally linked to evaporative scope and maximum
ratios of evaporative heat loss (EHL) to metabolic heat production
(MHP). We provide predictive equations for most variables related to
avian heat tolerance. Metabolic costs of heat dissipation pathways,
rather than capacity to increase EWL above baseline levels, appear to
represent the major constraint on the upper limits of avian heat
tolerance.The National Research Foundation and the National Science Foundation.http://jeb.biologists.orgam2022Zoology and Entomolog
Mapping evaporative water loss in desert passerines reveals an expanding threat of lethal dehydration
Extreme high environmental temperatures produce a variety of consequences for wildlife, including mass die-offs. Heat waves are increasing in frequency, intensity, and extent, and are projected to increase further under climate change. However, the spatial and temporal dynamics of die-off risk are poorly understood. Here, we examine the effects of heat waves on evaporative water loss (EWL) and survival in five desert passerine birds across the southwestern United States using a combination of physiological data, mechanistically informed models, and hourly geospatial temperature data. We ask how rates of EWL vary with temperature across species; how frequently, over what areas, and how rapidly lethal dehydration occurs; how EWL and die-off risk vary with body mass; and how die-off risk is affected by climate warming. We find that smaller-bodied passerines are subject to higher rates of mass-specific EWL than larger-bodied counterparts and thus encounter potentially lethal conditions much more frequently, over shorter daily intervals, and over larger geographic areas. Warming by 4 °C greatly expands the extent, frequency, and intensity of dehydration risk, and introduces new threats for larger passerine birds, particularly those with limited geographic ranges. Our models reveal that increasing air temperatures and heat wave occurrence will potentially have important impacts on the water balance, daily activity, and geographic distribution of arid-zone birds. Impacts may be exacerbated by chronic effects and interactions with other environmental changes. This work underscores the importance of acute risks of high temperatures, particularly for small-bodied species, and suggests conservation of thermal refugia and water sources
Ericaceae do Parque Estadual da Serra do Papagaio, Minas Gerais, Brasil
O Parque Estadual da Serra do Papagaio está localizado na Serra da Mantiqueira, sul de Minas Gerais, abrigando um importante remanescente de Floresta Atlântica. Possui uma área de 22.917 ha., dos quais cerca de 50% apresenta altitudes acima de 1.800m. O levantamento florÃstico foi realizado entre os anos de 2009 e 2013 e os espécimes coletados foram depositados no Herbário Leopoldo Krieger (CESJ), da Universidade Federal de Juiz de Fora. O objetivo deste estudo foi apresentar o tratamento taxonômico para Ericaceae nesta unidade de conservação. Foram registradas 10 espécies pertencentes a três gêneros, sendo Gaultheria e Gaylussacia os mais ricos, ambos representados por quatro espécies cada, e Agarista representado por apenas duas espécies. São apresentadas chaves de identificação, descrições das espécies, ilustrações de caracteres diagnósticos e comentários de distribuição geográfica, ecológicos e taxonômicos
The impact of humidity on evaporative cooling in small desert birds exposed to high air temperatures
Environmental temperatures that exceed body temperature
(Tb) force endothermic animals to rely solely on evaporative
cooling to dissipate heat. However, evaporative heat dissipation
can be drastically reduced by environmental humidity,
imposing a thermoregulatory challenge. The goal of this study
was to investigate the effects of humidity on the thermoregulation
of desert birds and to compare the sensitivity of cutaneous
and respiratory evaporation to reduced vapor density
gradients. Rates of evaporative water loss, metabolic rate, and
Tb were measured in birds exposed to humidities ranging from
∼2 to 30 g H2O m23 (0%–100% relative humidity at 307C) at
air temperatures between 447 and 567C. In sociable weavers, a
species that dissipates heat primarily through panting, rates of
evaporative water loss were inhibited by as much as 36% by
high humidity at 487C, and these birds showed a high degree
of hyperthermia. At lower temperatures (407–447C), evaporative
water loss was largely unaffected by humidity in this
species. In Namaqua doves, which primarily use cutaneous
evaporation, increasing humidity reduced rates of evaporative
water loss, but overall rates of water loss were lower than those
observed in sociable weavers. Our data suggest that cutaneous
evaporation is more efficient than panting, requiring less water
to maintain Tb at a given temperature, but panting appears
less sensitive to humidity over the air temperature range investigated
here.DST/National Research Foundation Centre of
Excellencehttp://www.journals.uchicago.edutoc/pbz/tm201
Avian thermoregulation in the heat : evaporative cooling capacity of arid-zone Caprimulgiformes from two continents
Birds in the order Caprimulgiformes (nightjars and allies) have a
remarkable capacity for thermoregulation over a wide range of
environmental temperatures, exhibiting pronounced heterothermy in
cool conditions and extreme heat tolerance at high environmental
temperatures. We measured thermoregulatory responses to acute
heat stress in three species of Caprimulgiformes that nest in areas of
extreme heat and aridity, the common poorwill (Phalaenoptilus
nuttallii: Caprimulgidae) and lesser nighthawk (Chordeiles
acutipennis: Caprimulgidae) in the Sonoran Desert of Arizona, and
the Australian owlet-nightjar (Aegotheles cristatus: Aegothelidae) in
the mallee woodlands of South Australia. We exposed wild-caught
birds to progressively increasing air temperatures (Ta) and measured
resting metabolic rate (RMR), evaporative water loss (EWL), body
temperature (Tb) and heat tolerance limit (HTL; the maximum Ta
reached). Comparatively low RMR values were observed in all
species (0.35, 0.36 and 0.40 Wfor the poorwill, nighthawk and owletnightjar,
respectively), with Tb approximating Ta at 40°C and mild
hyperthermia occurring as Ta reached the HTL. Nighthawks and
poorwills reached HTLs of 60 and 62°C, respectively, whereas the
owlet-nightjar had a HTL of 52°C. RMR increased gradually above
minima at Ta of 42, 42 and 35°C, and reached 1.7, 1.9 and 2.0 times
minimum resting values at HTLs in the poorwill, nighthawk and owletnightjar,
respectively. EWL increased rapidly and linearly as Ta
exceeded Tb and resulted in maximum rates of evaporative heat
dissipation equivalent to 237–424% of metabolic heat production.
Bouts of gular flutter resulted in large transient increases in evaporative heat loss (50–123%) accompanied by only small
increments in RMR (<5%). The cavity-nesting/roosting owletnightjar
had a lower HTL and less efficient evaporative cooling
compared with the species that nest and/or roost on open desert
surfaces. The high efficiency of gular flutter for evaporative cooling,
combined with mild hyperthermia, provides the physiological basis for
defending Tb well below Ta in extreme heat and is comparable to the
efficient cooling observed in arid-zone columbids in which cutaneous
EWL is the predominant cooling pathway.The National Science Foundation
under IOS-1122228 to B.O.W.http://jeb.biologists.org2018-10-01am2018Zoology and Entomolog
The effect of orthodontic forces on calcitonin gene-related peptide (CGRP) expression in the human periodontal ligament and its relationship with the human dental pulp
The purpose of this study was to quantify the effect of moderate and severe orthodontic forces on Calcitonin gene-related peptide (CGRP) expression in the healthy human periodontal ligament (PDL) and its possible relationship with the human dental pulp
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