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2.
New Phytol ; 235(5): 1719-1728, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35599356

RESUMEN

Climate change has advanced plant phenology globally 4-6 d °C-1 on average. Such shifts are some of the most reported and predictable biological impacts of rising temperatures. Yet as climate change has marched on, phenological shifts have appeared muted over recent decades - failing to match simple predictions of an advancing spring with continued warming. The main hypothesis for these changing trends is that interactions between spring phenological cues - long-documented in laboratory environments - are playing a greater role in natural environments due to climate change. Here, we argue that accurately linking shifts observed in long-term data to underlying phenological cues is slowed by biases in observational studies and limited integration of insights from laboratory studies. We synthesize seven decades of laboratory experiments to quantify how phenological cue-space has been studied and how treatments compare with shifts caused by climate change. Most studies focus on one cue, limiting our ability to make accurate predictions, but some well-studied forest species offer opportunities to advance forecasting. We outline how greater integration of controlled-environment studies with long-term data could drive a new generation of laboratory experiments, built on physiological insights, that would transform our fundamental understanding of phenology and improve predictions.


Asunto(s)
Cambio Climático , Señales (Psicología) , Bosques , Estaciones del Año , Temperatura
3.
Glob Chang Biol ; 27(20): 4947-4949, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34355482

RESUMEN

Recently, multiple studies have reported declining phenological sensitivities (∆ days per ℃) with higher temperatures. Such observations have been used to suggest climate change is reshaping biological processes, with major implications for forecasts of future change. Here, we show that these results may simply be the outcome of using linear models to estimate nonlinear temperature responses, specifically for events that occur after a cumulative thermal threshold is met-a common model for many biological events. Corrections for the nonlinearity of temperature responses consistently remove the apparent decline. Our results show that rising temperatures combined with linear estimates based on calendar time produce the observations of declining sensitivity-without any shift in the underlying biology. Current methods may thus undermine efforts to identify when and how warming will reshape biological processes.


Asunto(s)
Cambio Climático , Temperatura
4.
New Phytol ; 230(2): 462-474, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33421152

RESUMEN

Climate change causes both temporal (e.g. advancing spring phenology) and geographic (e.g. range expansion poleward) species shifts, which affect the photoperiod experienced at critical developmental stages ('experienced photoperiod'). As photoperiod is a common trigger of seasonal biological responses - affecting woody plant spring phenology in 87% of reviewed studies that manipulated photoperiod - shifts in experienced photoperiod may have important implications for future plant distributions and fitness. However, photoperiod has not been a focus of climate change forecasting to date, especially for early-season ('spring') events, often assumed to be driven by temperature. Synthesizing published studies, we find that impacts on experienced photoperiod from temporal shifts could be orders of magnitude larger than from spatial shifts (1.6 h of change for expected temporal vs 1 min for latitudinal shifts). Incorporating these effects into forecasts is possible by leveraging existing experimental data; we show that results from growth chamber experiments on woody plants often have data relevant for climate change impacts, and suggest that shifts in experienced photoperiod may increasingly constrain responses to additional warming. Further, combining modeling approaches and empirical work on when, where and how much photoperiod affects phenology could rapidly advance our understanding and predictions of future spatio-temporal shifts from climate change.


Asunto(s)
Cambio Climático , Fotoperiodo , Plantas , Estaciones del Año , Temperatura
5.
Sci Rep ; 11(1): 818, 2021 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-33436640

RESUMEN

Urbanization-driven landscape changes are harmful to many species. Negative effects can be mitigated through habitat preservation and restoration, but it is often difficult to prioritize these conservation actions. This is due, in part, to the scarcity of species response data, which limit the predictive accuracy of modeling to estimate critical thresholds for biological decline and recovery. To address these challenges, we quantify effort required for restoration, in combination with a clear conservation objective and associated metric (e.g., habitat for focal organisms). We develop and apply this framework to coho salmon (Oncorhynchus kisutch), a highly migratory and culturally iconic species in western North America that is particularly sensitive to urbanization. We examine how uncertainty in biological parameters may alter locations prioritized for conservation action and compare this to the effect of shifting to a different conservation metric (e.g., a different focal salmon species). Our approach prioritized suburban areas (those with intermediate urbanization effects) for preservation and restoration action to benefit coho. We found that prioritization was most sensitive to the selected metric, rather than the level of uncertainty or critical threshold values. Our analyses highlight the importance of identifying metrics that are well-aligned with intended outcomes.

6.
Ecol Lett ; 22(4): 748-763, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30687988

RESUMEN

To understand and forecast biological responses to climate change, scientists frequently use field experiments that alter temperature and precipitation. Climate manipulations can manifest in complex ways, however, challenging interpretations of biological responses. We reviewed publications to compile a database of daily plot-scale climate data from 15 active-warming experiments. We find that the common practices of analysing treatments as mean or categorical changes (e.g. warmed vs. unwarmed) masks important variation in treatment effects over space and time. Our synthesis showed that measured mean warming, in plots with the same target warming within a study, differed by up to 1.6  ∘ C (63% of target), on average, across six studies with blocked designs. Variation was high across sites and designs: for example, plots differed by 1.1  ∘ C (47% of target) on average, for infrared studies with feedback control (n = 3) vs. by 2.2  ∘ C (80% of target) on average for infrared with constant wattage designs (n = 2). Warming treatments produce non-temperature effects as well, such as soil drying. The combination of these direct and indirect effects is complex and can have important biological consequences. With a case study of plant phenology across five experiments in our database, we show how accounting for drier soils with warming tripled the estimated sensitivity of budburst to temperature. We provide recommendations for future analyses, experimental design, and data sharing to improve our mechanistic understanding from climate change experiments, and thus their utility to accurately forecast species' responses.


Asunto(s)
Cambio Climático , Suelo , Plantas , Temperatura
7.
Am J Bot ; 105(10): 1771-1780, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30324664

RESUMEN

PREMISE OF THE STUDY: Plant phenology is a critical trait, as the timings of phenophases such as budburst, leafout, flowering, and fruiting, are important to plant fitness. Despite much study about when individual phenophases occur and how they may shift with climate change, little is known about how multiple phenophases relate to one another across an entire growing season. We test the extent to which early phenological stages constrain later ones, throughout a growing season, across 25 angiosperm tree species. METHODS: We observed phenology (budburst, leafout, flowering, fruiting, and senescence) of 118 individual trees across 25 species, from April through December 2015. KEY RESULTS: We found that early phenological events weakly constrain most later events, with the strongest constraints seen between consecutive stages. In contrast, interphase duration was a much stronger predictor of phenology, especially for reproductive events, suggesting that the development time of flowers and fruits may constrain the phenology of these events. CONCLUSIONS: Much of the variation in later phenological events can be explained by the timing of earlier events and by interphase durations. This highlights that a shift in one phenophase may often have cascading effects on later phases. Accurate forecasts of climate change impacts should therefore include multiple phenophases within and across years.


Asunto(s)
Cambio Climático , Clima , Árboles/crecimiento & desarrollo , Tiempo (Meteorología) , Boston , Flores/crecimiento & desarrollo , Reproducción , Estaciones del Año
8.
J Dev Orig Health Dis ; 9(4): 432-441, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29665872

RESUMEN

This study investigates relations of maternal N-3 and N-6 polyunsaturated fatty acids (PUFA) intake during pregnancy with offspring body mass index (BMI), height z-score and metabolic risk (fasting glucose, C-peptide, leptin, lipid profile) during peripuberty (8-14 years) among 236 mother-child pairs in Mexico. We used food frequency questionnaire data to quantify trimester-specific intake of N-3 alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); N-6 linoleic acid and arachidonic acid (AA); and N-6:N-3 (AA:EPA+DHA), which accounts for the fact that the two PUFA families have opposing effects on physiology. Next, we used multivariable linear regression models that accounted for maternal education and parity, and child's age, sex and pubertal status, to examine associations of PUFA intake with the offspring outcomes. In models where BMI z-score was the outcome, we also adjusted for height z-score. We found that higher second trimester intake of EPA, DHA and AA were associated with lower offspring BMI and height z-score. For example, each 1-s.d. increment in second trimester EPA intake corresponded with 0.25 (95% CI: 0.03, 0.47) z-scores lower BMI and 0.20 (0.05, 0.36) z-scores lower height. Accounting for height z-score in models where BMI z-score was the outcome attenuated estimates [e.g., EPA: -0.16 (-0.37, 0.05)], suggesting that this relationship was driven by slower linear growth rather than excess adiposity. Maternal PUFA intake was not associated with the offspring metabolic biomarkers. Our findings suggest that higher PUFA intake during mid-pregnancy is associated with lower attained height in offspring during peripuberty. Additional research is needed to elucidate mechanisms and to confirm findings in other populations.


Asunto(s)
Adiposidad/fisiología , Estatura , Índice de Masa Corporal , Ácidos Grasos Omega-3/administración & dosificación , Ácidos Grasos Omega-6/administración & dosificación , Obesidad/prevención & control , Efectos Tardíos de la Exposición Prenatal/prevención & control , Adiposidad/efectos de los fármacos , Adolescente , Adulto , Niño , Femenino , Humanos , Recién Nacido , Masculino , Persona de Mediana Edad , Obesidad/metabolismo , Embarazo , Estudios Prospectivos , Adulto Joven
9.
Methods Cell Biol ; 137: 143-172, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28065302

RESUMEN

Neural stem and progenitor cells in the developing cerebral cortex, but also when grown in culture, display a range of distinct phenomena during cytokinesis. Cleavage furrow ingression in neural progenitor cells can bisect their basal processes and, later on, result in midbody formation at the apical surface. After abscission, these midbodies are released as membrane-bound particles into the extracellular space, in contrast to uptake and degradation of postabscission midbodies in other cell types. Whether these cellular dynamics are unique to neural stem cells, or more ubiquitously found, and what biological significance these processes have for cell differentiation or cell-cell communication, are open questions that require a combination of approaches. Here, we discuss techniques to study the specific membrane dynamics underlying the basal process splitting and postabscission midbody release in neural stem cells. We provide some basic concepts and protocols to isolate, enrich and stain released midbodies, and follow midbody dynamics over time. Moreover, we discuss techniques to prepare cortical sections for high-voltage electron microscopy to visualize the fine basal processes of progenitor cells.


Asunto(s)
Separación Celular/métodos , Rastreo Celular/métodos , Citocinesis/genética , Células-Madre Neurales/ultraestructura , Animales , Diferenciación Celular/genética , División Celular/genética , Membrana Celular , Corteza Cerebral/ultraestructura , Células HeLa , Humanos , Microscopía Fluorescente
10.
Pediatr Obes ; 11(1): 68-74, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25891908

RESUMEN

BACKGROUND: Consumption of sugar-sweetened beverages (SSB) has been associated with risk of obesity, but little evidence exists to evaluate if age of introduction and cumulative SSB consumption increases risk in children. OBJECTIVES: The objective of the study was to estimate the relationship between age of introduction and cumulative SSB consumption with risk of obesity in 227 Mexican children. METHODS: SSB intake was measured every 6 months; age of introduction and cumulative consumption during the pre-school period were calculated. Height, weight, waist circumference, SSB intake and other relevant variables were measured at age 8-14 years and obesity defined using standard criteria. RESULTS: All participants were introduced to SSB before age 24 months and most (73%) before 12 months. Early SSB introduction (≤12 months) was not significantly associated with increased odds of obesity (odds ratio [OR] = 2.00, 95% confidence interval [CI]: 0.87, 4.59). However, children in the highest tertile of cumulative SSB consumption, compared with the lowest, had almost three times the odds of general (OR = 2.99, 95% CI: 1.27, 7.00) and abdominal (OR = 2.70, 95% CI: 1.03, 7.03) obesity at age 8-14 years. CONCLUSIONS: High SSB consumption increased the likelihood of obesity in 8-14-year-old children. Our results suggest that SSB intake should be delayed and excessive SSB consumption in pre-school period should be avoided.


Asunto(s)
Bebidas/efectos adversos , Promoción de la Salud/organización & administración , Obesidad Infantil/prevención & control , Niño , Fenómenos Fisiológicos Nutricionales Infantiles , Preescolar , Sacarosa en la Dieta , Femenino , Humanos , Masculino , México/epidemiología , Valor Nutritivo , Oportunidad Relativa , Obesidad Infantil/etiología , Estudios Prospectivos , Instituciones Académicas , Edulcorantes , Circunferencia de la Cintura
11.
Environ Int ; 83: 63-71, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26101084

RESUMEN

BACKGROUND: Studies from several countries report increases in rates of gestational diabetes mellitus (GDM) over recent decades. Exposure to environmental chemicals could contribute to this trend. OBJECTIVES: To determine the associations between plasticisers and metals measured in early pregnancy with impaired glucose tolerance (IGT) and GDM in a Canadian pregnancy cohort. METHODS: Women enrolled in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study were included if they had a singleton delivery and did not have pre-existing diabetes. Eleven phthalate metabolites and total bisphenol A (BPA) were measured in first-trimester urine samples, and four metals (lead, cadmium, mercury and arsenic) were measured in first-trimester blood samples. IGT and GDM were assessed in accordance with standard guidelines by chart review. Chemical concentrations were grouped by quartiles, and associations with outcomes were examined using logistic regression with adjustment for maternal age, race, pre-pregnancy BMI, and education. Restricted cubic spline analysis was performed to help assess linearity and nature of any dose-response relationships. RESULTS: Of 2001 women recruited into the MIREC cohort, 1274 met the inclusion criteria and had outcome data and biomonitoring data measured for at least one of the chemicals we examined. Elevated odds of GDM were observed in the highest quartile of arsenic exposure (OR = 3.7, 95% CI = 1.4-9.6) in the adjusted analyses. A significant dose-response relationship was observed in a cubic spline model between arsenic and odds of GDM (p < 0.01). No statistically significant associations were observed between phthalates or BPA or other metals with IGT or GDM. CONCLUSIONS: Our findings add to the growing body of evidence supporting the role of maternal arsenic exposure as a risk factor for gestational diabetes.


Asunto(s)
Compuestos de Bencidrilo/metabolismo , Diabetes Gestacional/epidemiología , Contaminantes Ambientales/metabolismo , Exposición Materna , Metales/metabolismo , Fenoles/metabolismo , Ácidos Ftálicos/metabolismo , Adolescente , Adulto , Arsénico/sangre , Arsénico/orina , Compuestos de Bencidrilo/sangre , Compuestos de Bencidrilo/orina , Canadá/epidemiología , Estudios de Cohortes , Diabetes Gestacional/etiología , Contaminantes Ambientales/sangre , Contaminantes Ambientales/orina , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Modelos Logísticos , Metales/sangre , Metales/orina , Fenoles/sangre , Fenoles/orina , Ácidos Ftálicos/sangre , Ácidos Ftálicos/orina , Embarazo , Primer Trimestre del Embarazo , Factores de Riesgo , Adulto Joven
12.
Pediatr Obes ; 10(5): 345-52, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25405952

RESUMEN

BACKGROUND: In adolescents the temporal directionality to the asthma and adiposity association remains unclear. Asthma may be a consequence of obesity; however, asthma may increase adiposity. OBJECTIVES: This study aimed to assess the associations between (i) baseline weight status and subsequent asthma and (ii) baseline asthma and subsequent weight status after 4 and 11 years of follow-up (N = 1543 and N = 1596, respectively) using data from three, sequentially enrolled population-based surveys of Norwegians aged 12-30 years from 1995 to 2008. METHODS: Weight status was defined as general (body mass index) or abdominal (waist circumference) underweight, normal weight, overweight or obesity. Self-report physician-diagnosed asthma defined asthma status. RESULTS: Over the longitudinal 11-year follow-up, baseline generally overweight or abdominally obese adolescents had increased risk of asthma. Likewise, baseline asthmatics had increased risk of general overweight or abdominal obesity. After sex stratification, these associations were stronger in males. Generally (odds ratio [OR] 1.90; 95% confidence interval [CI] 1.32, 2.73) or abdominally (OR 1.66; 95% CI 1.13, 2.44) overweight males were at increased risk of asthma. Baseline asthmatic males were also at increased risk of general (OR 2.14; 95% CI 1.54, 2.98) and abdominal (OR 1.77; 95% CI 1.27, 2.47) overweight. CONCLUSIONS: Among Norwegian adolescents, a bidirectional association of asthma and adiposity was observed in males. Each baseline condition increased the risk of the other condition over time. No association was observed in females.


Asunto(s)
Asma/fisiopatología , Obesidad Abdominal/fisiopatología , Adiposidad , Adolescente , Adulto , Asma/epidemiología , Asma/etiología , Índice de Masa Corporal , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Noruega/epidemiología , Obesidad Abdominal/complicaciones , Obesidad Abdominal/epidemiología , Oportunidad Relativa , Sobrepeso , Circunferencia de la Cintura , Adulto Joven
13.
Ecology ; 92(6): 1323-31, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21797160

RESUMEN

Does climate determine species' ranges? Rapid rates of anthropogenic warming make this classic ecological question especially relevant. We ask whether climate controls range limits by quantifying relationships between climatic variables (precipitation, temperature) and tree growth across the altitudinal ranges of six Pacific Northwestern conifers on Mt. Rainier, Washington, USA. Results for three species (Abies amabilis, Callitropsis nootkatensis, Tsuga mertensiana) whose upper limits occur at treeline (> 1600 m) imply climatic controls on upper range limits, with low growth in cold and high snowpack years. Annual growth was synchronized among individuals at upper limits for these high-elevation species, further suggesting that stand-level effects such as climate constrain growth more strongly than local processes. By contrast, at lower limits climatic effects on growth were weak for these high-elevation species. Growth-climate relationships for three low-elevation species (Pseudotsuga menziesii, Thuja plicata, Tsuga heterophylla) were not consistent with expectations of climatic controls on upper limits, which are located within closed-canopy forest (< 1200 m). Annual growth of these species was poorly synchronized among individuals. Our results suggest that climate controls altitudinal range limits at treeline, while local drivers (perhaps biotic interactions) influence growth in closed-canopy forests. Climate-change-induced range shifts in closed-canopy forests will therefore be difficult to predict accurately.


Asunto(s)
Altitud , Clima , Cupressaceae/crecimiento & desarrollo , Pinaceae/crecimiento & desarrollo , Nieve , Árboles/crecimiento & desarrollo , Washingtón
14.
Vox Sang ; 98(2): 108-15, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19719460

RESUMEN

BACKGROUND: The Mirasol Pathogen Reduction Technology System (PRT) for Plasma (CaridianBCT) is based on a riboflavin and UV light treatment process resulting in pathogen inactivation due to irreversible, photochemically induced damage of nucleic acids. This study evaluated the in vitro protein quality of plasma products treated with riboflavin and UV light following treatment and subsequent storage for up to 104 weeks at -30 degrees C. MATERIALS AND METHODS: Apheresis and whole blood-derived plasma products were combined with riboflavin solution and exposed to ultraviolet light. Treated plasma was then flash frozen, within 8 h of collection, stored at -30 degrees C for up to 104 weeks and analysed at different stages of storage using standard coagulation assays. Results were compared with paired, untreated units stored for the same intervals. RESULTS: The average percent protein retention for all time-points in PRT-treated plasma samples after 36, 69, 87 and 104 weeks of storage at -30 degrees C in comparison with controls held under similar conditions were: Total Protein, 101%, Factor VIII, 79%, Fibrinogen, 78%, Factor II, 87%, Factor XII, 86%, Factor X, 84% and Factor IX, 81%. Anticoagulant and inhibitor proteins showed between 90% and 100% retention after 1 year (52 weeks) and 69 weeks of storage. No clinically relevant complement activation was observed in treated and stored samples. CONCLUSION: Riboflavin and UV light-treated plasma demonstrates reductions in several plasma coagulation factors following treatment. This reduction in activity levels is noted immediately after treatment and remains relatively constant during 2 years of storage at -30 degrees C.


Asunto(s)
Eliminación de Componentes Sanguíneos/métodos , Proteínas Sanguíneas/análisis , Patógenos Transmitidos por la Sangre/aislamiento & purificación , Plasma/fisiología , Riboflavina/farmacología , Conservación de la Sangre/métodos , Criopreservación/métodos , Humanos , Plasma/efectos de los fármacos , Plasma/efectos de la radiación , Rayos Ultravioleta
15.
Bull Exp Biol Med ; 146(6): 812-5, 2008 Dec.
Artículo en Inglés, Ruso | MEDLINE | ID: mdl-19513392

RESUMEN

Three types of light mesh endoprostheses with different jersey structure were implanted into the anterior abdominal walls of 18 rabbits. Changes in the geometrical size and mechanical properties of the prostheses detected 3 months after implantation largely depended on the jersey structure and distribution of mature connective tissue in the structure of the material.


Asunto(s)
Fenómenos Biomecánicos , Prótesis e Implantes , Mallas Quirúrgicas , Pared Abdominal , Animales , Masculino , Ensayo de Materiales , Conejos
16.
Neurology ; 69(21): 2020-7, 2007 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-17928576

RESUMEN

BACKGROUND: Providers are increasingly being held accountable for the quality of care provided. While quality indicators have been used to benchmark the quality of care for a number of other disease states, no such measures are available for evaluating the quality of care provided to adults with epilepsy. In order to assess and improve quality of care, it is critical to develop valid quality indicators. Our objective is to describe the development of quality indicators for evaluating care of adults with epilepsy. As most care is provided in primary and general neurology care, we focused our assessment of quality on care within primary care and general neurology clinics. METHODS: We reviewed existing national clinical guidelines and systematic reviews of the literature to develop an initial list of quality indicators; supplemented the list with indicators derived from patient focus groups; and convened a 10-member expert panel to rate the appropriateness, reliability, and necessity of each quality indicator. RESULTS: From the original 37 evidence-based and 10 patient-based quality indicators, the panel identified 24 evidence-based and 5 patient-based indicators as appropriate indicators of quality. Of these, the panel identified 9 that were not necessary for high quality care. CONCLUSION: There is, at best, a poor understanding of the quality of care provided for adults with epilepsy. These indicators, developed based on published evidence, expert opinion, and patient perceptions, provide a basis to assess and improve the quality of care for this population.


Asunto(s)
Atención a la Salud/métodos , Atención a la Salud/normas , Epilepsia/diagnóstico , Epilepsia/terapia , Garantía de la Calidad de Atención de Salud/métodos , Garantía de la Calidad de Atención de Salud/normas , Terminología como Asunto , Humanos , Internacionalidad
17.
Bull Exp Biol Med ; 141(6): 688-90, 2006 Jun.
Artículo en Inglés, Ruso | MEDLINE | ID: mdl-17364050

RESUMEN

Burn trauma increased blood chemiluminescence, while lipopolysaccharide in a dose of 1 mg/kg potentiated this effect, activated LPO, and decreased plasma antioxidant activity. In erythrocytes, superoxide dismutase activity increased, while activity of peroxide-utilizing enzymes decreased. Myeloperoxidase content increased in the lungs and epidermis. The preparation of alpha-tocopherol, selenium aspartate, and ubiquinone abolished the effect of lipopolysaccharide, but did not modulate the increase in chemiluminescence under the influence of this agent.


Asunto(s)
Antioxidantes/uso terapéutico , Quemaduras/complicaciones , Endotoxemia/tratamiento farmacológico , Endotoxemia/etiología , Animales , Epidermis/metabolismo , Eritrocitos/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Lipopolisacáridos/sangre , Lipopolisacáridos/toxicidad , Mediciones Luminiscentes , Pulmón/metabolismo , Masculino , Neutrófilos/metabolismo , Peroxidasa/metabolismo , Ratas , Ratas Wistar , Compuestos de Selenio/uso terapéutico , Superóxido Dismutasa/metabolismo , Ubiquinona/uso terapéutico , alfa-Tocoferol/uso terapéutico
18.
Patol Fiziol Eksp Ter ; (4): 21-4, 2004.
Artículo en Ruso | MEDLINE | ID: mdl-15568499

RESUMEN

The experimental model of rat bilateral subdiaphragmatic stem vagotomy was used to study the role of parasympathetic nervous system in regulation of circulation and oxygen supply to the small intestine. Cut of the vagus nerves is shown to cause redistribution of the blood flow between gastroduodenal organs, to slow down local circulation, to reduce oxygen tension in the muscular lining of the jejunum, to raise water content in the wall and change magnetorelaxational characteristics. Morphologically this manifested in altered arteriolar and capillary configuration, dilation of the capacity microvessels, dystrophia of microvessel wall, red cell aggregation in capillaries and venules, defective permeability of the vascular wall. The above indices changed most 7 and 30 days after vagotomy. It is evident that impaired vagus innervation produces secondary circulation hypoxia in the small intestine.


Asunto(s)
Yeyuno/irrigación sanguínea , Consumo de Oxígeno , Sistema Nervioso Parasimpático/fisiología , Animales , Yeyuno/inervación , Masculino , Microcirculación/fisiología , Ratas , Flujo Sanguíneo Regional/fisiología , Factores de Tiempo , Vagotomía
19.
Bull Exp Biol Med ; 136(4): 420-2, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14714099

RESUMEN

Four variants of polytetrafluorethylene films differing by size of micropores and manufacturing technology were used for closing of the abdominal cavity under conditions of experimental peritonitis in rats. The results of tensiometry and planimetry helped us to select the optimal variant of polytetrafluorethylene film characterized by sufficient strength, minimum size of micropores, and causing minimum complications.


Asunto(s)
Abdomen/cirugía , Materiales Biocompatibles/uso terapéutico , Ensayo de Materiales/métodos , Peritonitis/cirugía , Peritonitis/terapia , Politetrafluoroetileno/uso terapéutico , Cavidad Abdominal/patología , Animales , Elasticidad , Masculino , Peritonitis/complicaciones , Peritonitis/etiología , Peritonitis/patología , Ratas , Ratas Wistar , Reoperación , Supuración/complicaciones , Resistencia a la Tracción , Factores de Tiempo
20.
Vestn Khir Im I I Grek ; 160(2): 81-6, 2001.
Artículo en Ruso | MEDLINE | ID: mdl-11496500

RESUMEN

Experiments in 5 pigs and 18 mongrel dogs have shown the possibility to close perforating ulcers with plates of biopolymer "Tachocomb". The method is proposed as an alternative to suturing perforations in the zone of pylorus in order to prevent stenosis of the pyloric part of the stomach. The experimental data obtained have confirmed good adhesive and stimulating properties of the fibrin-collagen substance. Successful results of using the method were demonstrated in 2 patients with perforating ulcers.


Asunto(s)
Adhesivo de Tejido de Fibrina , Hemostáticos , Úlcera Péptica Perforada/cirugía , Úlcera Gástrica/complicaciones , Adhesivos Tisulares , Adulto , Animales , Perros , Drenaje , Estudios de Seguimiento , Humanos , Masculino , Úlcera Péptica Perforada/patología , Estómago/patología , Úlcera Gástrica/patología , Porcinos , Factores de Tiempo
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