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1.
Malar J ; 23(1): 196, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38918779

RESUMEN

BACKGROUND: Malaria risk maps are crucial for controlling and eliminating malaria by identifying areas of varying transmission risk. In the Greater Mekong Subregion, these maps guide interventions and resource allocation. This article focuses on analysing changes in malaria transmission and developing fine-scale risk maps using five years of routine surveillance data in Laos (2017-2021). The study employed data from 1160 geolocated health facilities in Laos, along with high-resolution environmental data. METHODS: A Bayesian geostatistical framework incorporating population data and treatment-seeking propensity was developed. The models incorporated static and dynamic factors and accounted for spatial heterogeneity. RESULTS: Results showed a significant decline in malaria cases in Laos over the five-year period and a shift in transmission patterns. While the north became malaria-free, the south experienced ongoing transmission with sporadic outbreaks. CONCLUSION: The risk maps provided insights into changing transmission patterns and supported risk stratification. These risk maps are valuable tools for malaria control in Laos, aiding resource allocation, identifying intervention gaps, and raising public awareness. The study enhances understanding of malaria transmission dynamics and facilitates evidence-based decision-making for targeted interventions in high-risk areas.


Asunto(s)
Malaria , Laos/epidemiología , Incidencia , Humanos , Malaria/epidemiología , Malaria/transmisión , Medición de Riesgo , Teorema de Bayes
2.
Malar J ; 23(1): 297, 2024 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-39367414

RESUMEN

BACKGROUND: Namibia, a low malaria transmission country targeting elimination, has made substantial progress in reducing malaria burden through improved case management, widespread indoor residual spraying and distribution of insecticidal nets. The country's diverse landscape includes regions with varying population densities and geographical niches, with the north of the country prone to periodic outbreaks. As Namibia approaches elimination, malaria transmission has clustered into distinct foci, the identification of which is essential for deployment of targeted interventions to attain the southern Africa Elimination Eight Initiative targets by 2030. Geospatial modelling provides an effective mechanism to identify these foci, synthesizing aggregate routinely collected case counts with gridded environmental covariates to downscale case data into high-resolution risk maps. METHODS: This study introduces innovative infectious disease mapping techniques to generate high-resolution spatio-temporal risk maps for malaria in Namibia. A two-stage approach is employed to create maps using statistical Bayesian modelling to combine environmental covariates, population data, and clinical malaria case counts gathered from the routine surveillance system between 2018 and 2021. RESULTS: A fine-scale spatial endemicity surface was produced for annual average incidence, followed by a spatio-temporal modelling of seasonal fluctuations in weekly incidence and aggregated further to district level. A seasonal profile was inferred across most districts of the country, where cases rose from late December/early January to a peak around early April and then declined rapidly to a low level from July to December. There was a high degree of spatial heterogeneity in incidence, with much higher rates observed in the northern part and some local epidemic occurrence in specific districts sporadically. CONCLUSIONS: While the study acknowledges certain limitations, such as population mobility and incomplete clinical case reporting, it underscores the importance of continuously refining geostatistical techniques to provide timely and accurate support for malaria elimination efforts. The high-resolution spatial risk maps presented in this study have been instrumental in guiding the Namibian Ministry of Health and Social Services in prioritizing and targeting malaria prevention efforts. This two-stage spatio-temporal approach offers a valuable tool for identifying hotspots and monitoring malaria risk patterns, ultimately contributing to the achievement of national and sub-national elimination goals.


Asunto(s)
Malaria , Análisis Espacio-Temporal , Namibia/epidemiología , Malaria/epidemiología , Malaria/prevención & control , Humanos , Incidencia , Teorema de Bayes , Estaciones del Año , Medición de Riesgo/métodos
3.
Anal Bioanal Chem ; 414(10): 3165-3175, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35028692

RESUMEN

This article will debate the usefulness of POCT measurements and the contribution microdialysis can make to generating valuable information. A particular theme will be the rarely considered difference between ex vivo sampling, which typically generates only a static measure of concentration, and in vivo measurements that are subject to dynamic changes due to mass transfer. Those dynamic changes provide information about the patients' physiological state.


Asunto(s)
Microdiálisis , Humanos , Microdiálisis/métodos
4.
Anal Bioanal Chem ; 414(10): 3243-3255, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34936009

RESUMEN

The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more than one analyte with replicate measurements. The device is equipped with a microfluidic system, which provides sample mixing with the necessary chemicals and pumping samples, reagents and buffers into the measurement chip, and with integrated thin film amorphous silicon photodiodes for the fluorescence detection. Submicrometric fluorescent magnetic particles are used as support in the immunoassay in order to improve the efficiency of the assay. In particular, the magnetic feature is used to concentrate the antibody onto the sensing layer leading to a much faster implementation of the assay, while the fluorescent feature is used to increase the optical signal leading to a larger optical dynamic change and consequently a better sensitivity and a lower limit of detection. The design and development of the whole integrated optical device are here illustrated. In addition, detection of mycophenolic acid and cyclosporine A in spiked solutions and in microdialysate samples from patient blood with the implemented device are reported.


Asunto(s)
Inmunosupresores , Dispositivos Ópticos , Humanos , Inmunoensayo , Microfluídica , Silicio
5.
Clin Chem Lab Med ; 59(5): 935-945, 2021 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-33554521

RESUMEN

OBJECTIVES: Therapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for the initial phase of immunosuppressant therapy, e.g., with cyclosporine (CsA) and mycophenolic acid (MPA). METHODS: We analyzed the time course over 8 h of total and free of immunosuppressive drug (CsA and MPA) concentrations measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 16 kidney transplant patients. Besides repeated blood sampling, intravenous microdialysis was used for continuous sampling. Free drug concentrations were determined from ultracentrifuged EDTA-plasma (UC) and compared with the drug concentrations in the respective microdialysate (µD). µDs were additionally analyzed for free CsA using a novel immunosensor chip integrated into a fluorescence detection platform. The potential of microdialysis coupled with an optical immunosensor for the TDM of immunosuppressants was assessed. RESULTS: Using LC-MS/MS, the free concentrations of CsA (fCsA) and MPA (fMPA) were detectable and the time courses of total and free CsA comparable. fCsA and fMPA and area-under-the-curves (AUCs) in µDs correlated well with those determined in UCs (r≥0.79 and r≥0.88, respectively). Moreover, fCsA in µDs measured with the immunosensor correlated clearly with those determined by LC-MS/MS (r=0.82). CONCLUSIONS: The new microdialysis-supported immunosensor allows real-time analysis of immunosuppressants and tailor-made dosing according to the AUC concept. It readily lends itself to future applications as minimally invasive and continuous near-patient TDM.


Asunto(s)
Técnicas Biosensibles , Inmunosupresores , Cromatografía Liquida , Monitoreo de Drogas , Humanos , Inmunoensayo , Ácido Micofenólico , Preparaciones Farmacéuticas , Espectrometría de Masas en Tándem
6.
J Sci Food Agric ; 101(5): 2100-2107, 2021 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-32978810

RESUMEN

BACKGROUND: Soluble solids concentration (SSC), dry matter concentration (DMC) and flesh firmness (FF) are important fruit quality parameters in stone fruits. This study investigated the ability of a commercial visible/near-infrared (NIR) spectrometer to determine SSC, DMC and FF in nectarine, peach, apricot and Japanese plum cultivars at harvest. The work was conducted in summer 2019/2020 on 14 stone fruit cultivars at Tatura, Australia. Two sub-samples of 100 fruit each were collected before and after commercial maturity (± 5 days) in order to maximize sample variability. RESULTS: Partial least square (PLS) regression models based on the second derivative of the absorbance in the 729-975 nm spectral region proved accurate for the prediction of SSC and DMC (R2 CV > 0.750). Only the model generated for SSC in 'Golden May' apricot was less precise compared to other cultivars. No visible/NIR models were accurate enough to predict FF in the cultivars under study (R2 CV < 0.750). CONCLUSION: This study demonstrated that the visible/NIR spectrometer was a reliable tool to monitor SSC and DMC in stone fruits at harvest but proved less useful for FF estimation. These results highlight the potential of visible/NIR spectrometry to evaluate stone fruit quality both in situ pre-harvest and in the laboratory after harvest. © 2020 Society of Chemical Industry.


Asunto(s)
Frutas/química , Espectroscopía Infrarroja Corta/métodos , Dureza , Prunus armeniaca/química , Prunus domestica/química , Prunus persica/química
7.
Sensors (Basel) ; 20(22)2020 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-33212792

RESUMEN

Technology for rapid, non-invasive and accurate determination of fruit maturity is increasingly sought after in horticultural industries. This study investigated the ability to predict fruit maturity of yellow peach cultivars using a prototype non-destructive fluorescence spectrometer. Collected spectra were analysed to predict flesh firmness (FF), soluble solids concentration (SSC), index of absorbance difference (IAD), skin and flesh colour attributes (i.e., a* and H°) and maturity classes (immature, harvest-ready and mature) in four yellow peach cultivars-'August Flame', 'O'Henry', 'Redhaven' and 'September Sun'. The cultivars provided a diverse range of maturity indices. The fluorescence spectrometer consistently predicted IAD and skin colour in all the cultivars under study with high accuracy (Lin's concordance correlation coefficient > 0.85), whereas flesh colour's estimation was always accurate apart from 'Redhaven'. Except for 'September Sun', good prediction of FF and SSC was observed. Fruit maturity classes were reliably predicted with a high likelihood (F1-score = 0.85) when samples from the four cultivars were pooled together. Further studies are needed to assess the performance of the fluorescence spectrometer on other fruit crops. Work is underway to develop a handheld version of the fluorescence spectrometer to improve the utility and adoption by fruit growers, packhouses and supply chain managers.


Asunto(s)
Frutas , Prunus persica , Espectrometría de Fluorescencia , Color , Productos Agrícolas
8.
South Med J ; 110(5): 319-324, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28464171

RESUMEN

OBJECTIVES: The flipped classroom module incorporates independent study in advance of in-class instructional sessions. It is unproven whether this methodology is effective within a medical school second-year organ system module. We report the development, implementation, and effectiveness of the flipped classroom methodology in a second-year medical student dermatology module at the University of Miami Leonard M. Miller School of Medicine. METHODS: In a retrospective cohort analysis, we compared attitudinal survey data and mean scores for a 50-item multiple-choice final examination of the second-year medical students who participated in this 1-week flipped course with those of the previous year's traditional, lecture-based course. RESULTS: Each group comprised nearly 200 students. Students' age, sex, Medical College Admission Test scores, and undergraduate grade point averages were comparable between the flipped and traditional classroom students. The flipped module students' mean final examination score of 92.71% ± 5.03% was greater than that of the traditional module students' 90.92% ± 5.51% (P < 0.001) score. Three of the five most commonly missed questions were identical between the two cohorts. The majority of students preferred the flipped methodology to attending live lectures or watching previously recorded lectures. CONCLUSIONS: The flipped classroom can be an effective instructional methodology for a medical school second-year organ system module.


Asunto(s)
Dermatología/educación , Educación de Pregrado en Medicina/métodos , Evaluación Educacional , Femenino , Florida , Humanos , Masculino , Estudios Retrospectivos , Facultades de Medicina , Estudiantes de Medicina , Encuestas y Cuestionarios , Adulto Joven
9.
Trop Med Infect Dis ; 8(7)2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-37505659

RESUMEN

No studies have yet examined high-resolution shifts in the spatial patterns of human movement in Australia throughout 2020 and 2021, a period coincident with the repeated enactment and removal of varied governmental restrictions aimed at reducing community transmission of SARS-CoV-2. We compared overlapping timeseries of COVID-19 pandemic-related restrictions, epidemiological data on cases and vaccination rates, and high-resolution human movement data to characterize population-level responses to the pandemic in Australian cities. We found that restrictions on human movement and/or mandatory business closures reduced the average population-level weekly movement volumes in cities, as measured by aggregated travel time, by almost half. Of the movements that continued to occur, long movements reduced more dramatically than short movements, likely indicating that people stayed closer to home. We also found that the repeated lockdowns did not reduce their impact on human movement, but the effect of the restrictions on human movement waned as the duration of restrictions increased. Lastly, we found that after restrictions ceased, the subsequent surge in SARS-CoV-2 transmission coincided with a substantial, non-mandated drop in human movement volume. These findings have implications for public health policy makers when faced with anticipating responses to restrictions during future emergency situations.

10.
Brain ; 134(Pt 2): 484-94, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21247930

RESUMEN

Secondary insults can adversely influence outcome following severe traumatic brain injury. Monitoring of cerebral extracellular chemistry with microdialysis has the potential for early detection of metabolic derangements associated with such events. The objective of this study was to determine the relationship between the fundamental biochemical markers and neurological outcome in a large cohort of patients with traumatic brain injury. Prospectively collected observational neuromonitoring data from 223 patients were analysed. Monitoring modalities included digitally recorded intracranial pressure, cerebral perfusion pressure, cerebrovascular pressure reactivity index and microdialysis markers glucose, lactate, pyruvate, glutamate, glycerol and the lactate/pyruvate ratio. Outcome was assessed using the Glasgow Outcome Scale at 6 months post-injury. Patient-averaged values of parameters were used in statistical analysis, which included univariate non-parametric methods and multivariate logistic regression. Monitoring with microdialysis commenced on median (interquartile range) Day 1 (1-2) from injury and median (interquartile range) duration of monitoring was 4 (2-7) days. Averaged over the total monitoring period levels of glutamate (P = 0.048), lactate/pyruvate ratio (P = 0.044), intracranial pressure (P = 0.006) and cerebrovascular pressure reactivity index (P = 0.01) were significantly higher in patients who died. During the initial 72 h of monitoring, median glycerol levels were also higher in the mortality group (P = 0.014) and median lactate/pyruvate ratio (P = 0.026) and lactate (P = 0.033) levels were significantly lower in patients with favourable outcome. In a multivariate logistic regression model (P < 0.0001), which employed data averaged over the whole monitoring period, significant independent positive predictors of mortality were glucose (P = 0.024), lactate/pyruvate ratio (P = 0.016), intracranial pressure (P = 0.029), cerebrovascular pressure reactivity index (P = 0.036) and age (P = 0.003), while pyruvate was a significant independent negative predictor of mortality (P = 0.004). The results of this study suggest that extracellular metabolic markers are independently associated with outcome following traumatic brain injury. Whether treatment-related improvement in biochemistry translates into better outcome remains to be established.


Asunto(s)
Lesiones Encefálicas/metabolismo , Corteza Cerebral/lesiones , Corteza Cerebral/metabolismo , Líquido Extracelular/química , Microdiálisis/métodos , Adulto , Biomarcadores/metabolismo , Lesiones Encefálicas/mortalidad , Corteza Cerebral/irrigación sanguínea , Femenino , Escala de Coma de Glasgow , Escala de Consecuencias de Glasgow , Glucosa/metabolismo , Ácido Glutámico/metabolismo , Glicerol/metabolismo , Humanos , Presión Intracraneal , Ácido Láctico/metabolismo , Masculino , Persona de Mediana Edad , Ácido Pirúvico/metabolismo
11.
J Res Med Sci ; 17(3): 298-303, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23267384

RESUMEN

BACKGROUND: Despite an increased need, residents of rural communities have decreased access to healthcare and oftenpresentuniquehealthcare challenges associated with their rurality. Ensuring medical students receive adequate exposure to these issues is complicated by the urban location of most medical schools. Health fairs (fairs) conducted in rural communities can provide students exposure to ruralhealth;however, it is unknown how participation affects attitudes regarding these issues. MATERIALS AND METHODS: During the 2010-2011 academic year, first-year medical students were surveyed before and after participating in a rural fair regarding the importance of rural health issues, the need for exposure to rural healthcare, their plans to practice in a rural community,andthe educational impact of fairs. RESULTS: Of the 121participating students, 77% and 61% completed pre- and post-fair surveys, respectively. Few had lived in a rural area or planned to practice primary care. Participants strongly agreed that the delivery of healthcare in rural areas was important, and that all physicians should receive rural health training (4.8 and 3.7 out of 5, respectively) despite less than halfplanning to practice in a rural community. After participating in a rural fair, student attitudes were unchanged, although 87% of participants strongly agreed their involvement had contributed to improving patient health and 70% that the fairs provided rural medicine experience. CONCLUSIONS: Among urban medical school students with varied interests in primary care, there was strong interest in volunteering at rural fairs and appreciation for the importance of rural health. Fairs provided interested students with rural medicine experience that reinforced student attitudes regarding rural health. Further, students felt their participation improved patient health.

12.
Am J Gastroenterol ; 106(10): 1741-6, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21979199

RESUMEN

OBJECTIVES: Only half of eligible patients in the United States undergo colorectal cancer (CRC) screening as recommended. Hypothesizing that the medical philanthropy platform may be effective in improving access to CRC screening, we aimed to demonstrate the feasibility of a flexible sigmoidoscopy (FS)-based CRC screening "health fair" for uninsured patients. METHODS: Uninsured patients older than 50 years who had not undergone CRC screening in the preceding 10 years were recruited through local free clinics and health fairs. A standard medical clinic was transformed into a fully functional endoscopy unit. Medicolegal protection for volunteers was obtained through the Florida Department of Health's Volunteer Health Care Provider Program. Unsedated FS with polypectomy was performed. Those with high-risk endoscopic features were given instructions on obtaining a full colonoscopy. RESULTS: Fifty-two patients without access to any form of CRC screening underwent FS. Ninety-four percent had an adequate bowel preparation, although 40% required on-site enema. Eighteen patients had a total of 22 polyps, 4 of which were adenomatous. There were no complications. The total cost of the fair, excluding donated resources such as endoscopes and processors, was $6,531.47, amounting to $126 per patient screened. CONCLUSIONS: Health fair-style CRC screening for uninsured patients is feasible. With improved efficiency, widespread application of CRC screening using the medical philanthropy platform may represent a viable approach to reducing the underuse of CRC screening among the uninsured.


Asunto(s)
Neoplasias Colorrectales/economía , Neoplasias Colorrectales/prevención & control , Costos Directos de Servicios , Detección Precoz del Cáncer/economía , Obtención de Fondos , Accesibilidad a los Servicios de Salud , Sigmoidoscopía/economía , Anciano , Neoplasias Colorrectales/diagnóstico , Costos Directos de Servicios/estadística & datos numéricos , Estudios de Factibilidad , Femenino , Florida , Accesibilidad a los Servicios de Salud/economía , Humanos , Masculino , Persona de Mediana Edad , Estados Unidos
13.
South Med J ; 104(8): 598-603, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21886071

RESUMEN

OBJECTIVES: Residents of rural communities, especially in the Southeast, have decreased access to health care. Ensuring medical students receive adequate exposure to their issues is complicated by the urban location of most schools. We describe health fairs conducted in rural communities to suggest how having medical students use screening tools can identify patients with risk factors for disease which can offer students the opportunity to learn about rural health issues through patient counseling. METHODS: The Mitchell Wolfson Sr. Department of Community Service, a University of Miami Miller School of Medicine student-led organization, conducts fairs at four sites throughout the rural Florida Keys. Medical students, under the supervision of attending physicians, offer screening and preventive health services including risk factor screening for cardiovascular disease, ophthalmological exams, dermatologic exams, osteoporosis screening, and female exams with pap smears. These fairs were reviewed. RESULTS: In the past three years, 1694 unique patients were seen. Many lacked a primary care provider (46%) or health insurance (43%) and were provided screening for several disorders including cardiovascular disease risk factors (hypertension, diabetes, dyslipidemia, and obesity). Screening revealed that many patients (41%) had multiple markers of elevated cardiovascular disease risk. This provided experiences to more than 200 students each year. CONCLUSION: Fairs provide medical students exposure to rural health issues through the valuable opportunity of using risk factor screening tools and counseling. This provides valuable information to patients of rural communities. Future research should examine how fairs influence student knowledge and attitudes toward rural health and affect health outcomes.


Asunto(s)
Exposiciones Educacionales en Salud/métodos , Promoción de la Salud , Accesibilidad a los Servicios de Salud , Tamizaje Masivo , Población Rural , Estudiantes de Medicina , Adolescente , Adulto , Anciano , Enfermedades Cardiovasculares/diagnóstico , Educación Médica/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Adulto Joven
14.
Acta Neurochir (Wien) ; 151(1): 51-61; discussion 61, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19099177

RESUMEN

BACKGROUND: Microdialysis continuously monitors the chemistry of a small focal volume of the cerebral extracellular space. Positron emission tomography (PET) establishes metabolism of the whole brain but only for the scan's duration. This study's objective was to apply these techniques together, in patients with traumatic brain injury, to assess the relationship between microdialysis (extracellular glucose, lactate, pyruvate, and the lactate/pyruvate (L/P) ratio as a marker of anaerobic metabolism) and PET parameters of glucose metabolism using the glucose analogue [(18)F]-fluorodeoxyglucose (FDG). In particular, we aimed to determine the fate of glucose in terms of differential metabolism to pyruvate and lactate. MATERIALS AND METHODS: Microdialysis catheters (CMA70 or CMA71) were inserted into the cerebral cortex of 17 patients with major head injury. Microdialysis was performed during FDG-PET scans with regions of interest for PET analysis defined by the location of the gold-tipped microdialysis catheter. Microdialysate analysis was performed on a CMA600 analyser. FINDINGS: There was significant linear relationship between the PET-derived parameter of glucose metabolism (regional cerebral metabolic rate of glucose; CMRglc) and levels of lactate (r = 0.778, p < 0.0001) and pyruvate (r = 0.799, p < 0.0001), but not with the L/P ratio. CONCLUSION: The results suggest that in this population of patients, glucose was metabolised to both lactate and pyruvate, but was not associated with an increase in the L/P ratio. This suggests an increase in glucose metabolism to both lactate and pyruvate, as opposed to a shift towards anaerobic metabolism.


Asunto(s)
Lesiones Encefálicas/diagnóstico por imagen , Lesiones Encefálicas/metabolismo , Encéfalo/metabolismo , Glucosa/metabolismo , Tomografía de Emisión de Positrones/métodos , Adolescente , Adulto , Anciano , Biomarcadores/análisis , Biomarcadores/metabolismo , Encéfalo/fisiopatología , Lesiones Encefálicas/fisiopatología , Metabolismo Energético/fisiología , Líquido Extracelular/metabolismo , Femenino , Fluorodesoxiglucosa F18 , Glucosa/análisis , Glucólisis/fisiología , Humanos , Ácido Láctico/análisis , Ácido Láctico/metabolismo , Masculino , Microdiálisis/métodos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Ácido Pirúvico/análisis , Ácido Pirúvico/metabolismo , Adulto Joven
15.
J Plant Physiol ; 237: 104-110, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31055228

RESUMEN

Biophysical fruit growth depends on a balance among the vascular and transpiration flows entering/exiting the fruit via phloem, xylem and through the epidermis. There is no information on vascular flows of Japanese plums, a species characterized by high-sugar content of its fruit at harvest. Vascular flows of Angeleno plums were monitored by fruit gauges during late fruit development, under the dry environment of the Goulburn Valley, Victoria, Australia. Phloem, xylem flows and skin transpiratory losses were determined, as well as diurnal leaf, stem and fruit pressure potentials. Fruit seasonal development, skin conductance and dry matter accumulation were also monitored. Fruit grew following a double-sigmoid pattern, but fruit size increased only 3.1 g over the last 3 weeks of development. Fruit grew very little in the morning, primarily due to phloem inflows (0.05 g fruit-1hr-1), while water left the fruit via the xylem. Negligible skin transpiration was recorded for vapour pressure deficit (VPD) values below 3 kPa. This growth pattern, in the absence of skin transpiration, suggests apoplastic phloem unloading. However, at VPD values over 3 kPa (e.g. from early afternoon to a peak around 18:00 h), transpiratory losses through the skin (up to 0.25 g fruit-1hr-1) caused fruit to shrink, leading to enhanced phloem and xylem inflows (ca. 0.15 g fruit-1hr-1), a scenario that would correspond to symplastic phloem unloading. Over 24 h the fruit showed a slightly negative total growth, consistent with fruit growth measured in situ during the season at weekly intervals. A few fruit species are known to alter their phloem unloading mechanism, switching from symplastic to apoplastic during the season. Our data support the coexistence in Japanese plum of different phloem unloading strategies within the same day.


Asunto(s)
Floema/fisiología , Transpiración de Plantas/fisiología , Prunus domestica/fisiología , Aumento de la Célula , Ambiente , Frutas/crecimiento & desarrollo , Frutas/fisiología , Victoria
16.
Front Plant Sci ; 10: 805, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31333685

RESUMEN

Continuous assessment of plant water status indicators provides the most precise information for irrigation management and automation, as plants represent an interface between soil and atmosphere. This study investigated the relationship of plant water status to continuous fruit diameter (FD) and inverse leaf turgor pressure rates (p p) in nectarine trees [Prunus persica (L.) Batsch] throughout fruit development. The influence of deficit irrigation treatments on stem (Ψ stem) and leaf water potential, leaf relative water content, leaf stomatal conductance, and fruit growth was studied across the stages of double-sigmoidal fruit development in 'September Bright' nectarines. Fruit relative growth rate (RGR) and leaf relative pressure change rate (RPCR) were derived from FD and p p to represent rates of water in- and outflows in the organs, respectively. Continuous RGR and RPCR dynamics were independently and jointly related to plant water status and environmental variables. The independent use of RGR and RPCR yielded significant associations with midday Ψ stem, the most representative index of tree water status in anisohydric species. However, a combination of nocturnal fruit and leaf parameters unveiled an even more significant relationship with Ψ stem, suggesting a changing behavior of fruit and leaf water flows in response to pronounced water deficit. In conclusion, we highlight the suitability of a dual-organ sensing approach for improved prediction of tree water status.

17.
J Neurosci ; 26(15): 3942-50, 2006 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-16611810

RESUMEN

Dysfunction of the 140 aa protein alpha-synuclein plays a central role in Lewy body disorders, including Parkinson's disease, as well as in multiple system atrophy. Here, we show that the expression of truncated human alpha-synuclein(1-120), driven by the rat tyrosine hydroxylase promoter on a mouse alpha-synuclein null background, leads to the formation of pathological inclusions in the substantia nigra and olfactory bulb and to a reduction in striatal dopamine levels. At the behavioral level, the transgenic mice showed a progressive reduction in spontaneous locomotion and an increased response to amphetamine. These findings suggest that the C-terminal of alpha-synuclein is an important regulator of aggregation in vivo and will help to understand the mechanisms underlying the pathogenesis of Lewy body disorders and multiple system atrophy.


Asunto(s)
Dopamina/fisiología , Cuerpos de Lewy/patología , Enfermedad por Cuerpos de Lewy/patología , Neuronas/patología , Bulbo Olfatorio/patología , Sustancia Negra/patología , alfa-Sinucleína/genética , Animales , Humanos , Enfermedad por Cuerpos de Lewy/genética , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Ratones Transgénicos , Enfermedad de Parkinson/genética , Enfermedad de Parkinson/patología , Regiones Promotoras Genéticas , Ratas , Tirosina 3-Monooxigenasa/genética
18.
J Neurotrauma ; 24(10): 1545-57, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17970618

RESUMEN

Following traumatic brain injury (TBI), cascades of inflammatory processes occur. Laboratory studies implicate the cytokines interleukin-1alpha (IL-1alpha) and IL-1beta in the pathophysiology of TBI and cerebral ischemia, whilst exogenous and endogenous interleukin-1 receptor antagonist (IL-1ra) is neuroprotective. We analyzed IL-1alpha, IL-1beta, and IL-1ra in brain microdialysates (100-kDa membrane) in 15 TBI patients. We also analyzed energy-related molecules (glucose, lactate, pyruvate, glutamate, and the lactate/pyruvate ratio) in these brain microdialysates. Mean of mean (+/-SD) in vitro microdialysis percentage recoveries (extraction efficiencies) were IL-1alpha 19.7+/-7.6%, IL-1beta 23.9+/-10.5%, and IL-1ra 20.9+/-6.3%. In the patients' brain microdialysates, mean of mean cytokine concentrations (not corrected for percentage recovery) were IL-1alpha 5.6+/-14.8 pg/mL, IL-1beta 10.4+/-14.7 pg/mL, and IL-1ra 2796+/-2918 pg/mL. IL-1ra was consistently much higher than IL-1alpha and IL-1beta. There were no significant relationships between IL-1 family cytokines and energy-related molecules. There was a significant correlation between increasing IL-1beta and increasing IL-1ra (Spearman r=0.59, p=0.028). There was also a significant relationship between increasing IL-1ra and decreasing intracranial pressure (Spearman r=-0.57, p=0.041). High concentrations of IL-1ra, and also high IL-1ra/IL-1beta ratio, were associated with better outcome (Mann Whitney, p=0.018 and p=0.0201, respectively), within these 15 patients. It is unclear whether these IL-1ra concentrations are sufficient to antagonize the effects of IL-1beta in vivo. This study demonstrates feasibility of our microdialysis methodology in recovering IL-1 family cytokines for assessing their inter-relationships in the injured human brain, and suggests a neuroprotective role for IL-1ra. It remains to be seen whether exogenous IL-1ra or other agents can be used to manipulate cytokine levels in the brain, for potential therapeutic effect.


Asunto(s)
Química Encefálica/fisiología , Lesiones Encefálicas/fisiopatología , Inflamación/fisiopatología , Proteína Antagonista del Receptor de Interleucina 1/análisis , Interleucina-1alfa/análisis , Interleucina-1beta/análisis , Adolescente , Adulto , Anciano , Lesiones Encefálicas/metabolismo , Femenino , Humanos , Inflamación/metabolismo , Proteína Antagonista del Receptor de Interleucina 1/metabolismo , Interleucina-1alfa/metabolismo , Interleucina-1beta/metabolismo , Masculino , Microdiálisis , Persona de Mediana Edad
19.
Acad Med ; 82(4): 383-9, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17414196

RESUMEN

In August 2007, the first class of University of Miami Miller School of Medicine (UM) medical students will begin the four-year undergraduate medical education program at the regional medical campus at Florida Atlantic University (FAU) The authors describe how UM and FAU were able to make a successful case to state policymakers for a regional medical campus as a cost-effective approach to expanding undergraduate and graduate medical education opportunities in southeast Florida The authors discuss what motivated UM and FAU to partner to create a regional medical campus, and they describe the challenges that have been encountered since 2004, particularly those relating to delivering a comparable two-year program on two campuses using distance-learning technologies. The opportunities that have resulted from expansion of the regional campus from two to four years are also described, including the development of a new and innovative four-year curriculum emphasizing comprehensive chronic disease management and case-based and patient-centered education using collaborative, small-group student learning communities. UM medical students thus have a choice between two educational tracks. The authors conclude that no significant impediments have resulted from the Florida collaboration between a public and a private university and that the regional medical campus model can serve as a viable option for other states and institutions attempting to expand medical school enrollment and meet physician workforce needs in an efficient and cost-effective manner.


Asunto(s)
Educación de Postgrado en Medicina , Educación de Pregrado en Medicina , Financiación del Capital/economía , Análisis Costo-Beneficio , Educación de Postgrado en Medicina/economía , Educación de Pregrado en Medicina/economía , Florida , Humanos , Internado y Residencia , Formulación de Políticas , Ubicación de la Práctica Profesional , Asignación de Recursos , Facultades de Medicina/economía , Estudiantes de Medicina
20.
Ambio ; 46(1): 98-108, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27380216

RESUMEN

The wetlands of Saudi Arabia are located in a water-stressed region that is highly vulnerable to climate and other global changes. Sebkhas, mudflats, mangroves, and wadis are the dominant wetlands in the arid regions of North Africa and the Arabian Peninsula. These unique wetlands are recognized as a sanctuary for biodiversity and for their economic services generated from mineral extraction, agriculture, and grazing. Despite their ecological values and societal services, the long-term permanence of Saudi Arabia's wetlands faces strong challenges resulting from human activities associated with sustained population growth, habitat degradation, and coastal development. This paper consolidates a literature review of Saudi Arabia's wetlands from local to global importance, highlights their biodiversity, and identifies threats and evolution of these vulnerable ecosystems in the arid Arabian Peninsula by focusing on the status of key freshwater taxa (Odonata, freshwater fishes, amphibians, and waterbirds) and documenting changes affecting important wetlands.


Asunto(s)
Organismos Acuáticos/crecimiento & desarrollo , Conservación de los Recursos Naturales/métodos , Conservación de los Recursos Naturales/tendencias , Humedales , Organismos Acuáticos/clasificación , Biodiversidad , Imágenes Satelitales , Arabia Saudita
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