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1.
Environ Sci Technol ; 55(18): 12694-12703, 2021 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-34506717

RESUMEN

Saharan dust is an important phosphorus (P) supply to remote and oligotrophic parts of the oceans and American lowland tropical rainforests. Phosphorus speciation in aeolian dust ultimately controls the release and bioavailability of P after dust deposition, but the speciation in Saharan dust and its change during the trans-Atlantic transport remains unclear. Using P K-edge X-ray absorption near edge structure (XANES) spectroscopy, we showed that with increasing dust traveling distance from the Sahara Desert to Cape Verde and to Puerto Rico, about 570 and 4000 km, respectively, the proportion of Ca-bound P (Ca-P), including both apatite and non-apatite forms, decreased from 68-73% to 50-71% and to 21-37%. The changes were accompanied by increased iron/aluminum-bound P proportion from 14-25% to 23-46% and to 44-73%, correspondingly. Laboratory simulation experiments suggest that the changes in P speciation can be ascribed to increasing degrees of particle sorting and atmospheric acidification during dust transport. The presence of relatively soluble non-apatite Ca-P in the Cape Verde dust but not in the Puerto Rico dust is consistent with the higher P water solubility of the former than the latter. Our findings provide insights into the controls of atmospheric processes on P speciation, solubility, and stability in Saharan dust.


Asunto(s)
Polvo , Fósforo , Polvo/análisis , Océanos y Mares , Fósforo/análisis , Espectroscopía de Absorción de Rayos X , Rayos X
2.
Med J Malaysia ; 75(1): 83-85, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-32008028

RESUMEN

Kimura disease (KD) is a rare benign chronic inflammatory disease that presents as a nodule mostly involving deep subcutaneous tissue of the head and neck region with frequent regional lymphadenopathy and peripheral blood eosinophilia. KD shares some clinical and histopathological similarity with angiolymphoid hyperplasia with eosinophilia (ALHE). Consequently, KD and ALHE were once considered variants of the same disease spectrum. We present here rare cases of Kimura disease and ALHE involving the eyelid and lacrimal gland and discuss their differential features.


Asunto(s)
Hiperplasia Angiolinfoide con Eosinofilia/diagnóstico , Párpados/fisiopatología , Enfermedad de Kimura/diagnóstico , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud
3.
Aust Vet J ; 102(3): 67-73, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37875328

RESUMEN

Classical swine fever virus (CSFV) identification has witnessed significant advancements with the development of rapid reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assays. However, conventional RT-LAMP assays for CSFV diagnosis are hindered by a laborious RNA extraction step. Moreover, the need for thermal incubators and expensive micropipettes has limited their application in field settings. Addressing these challenges, our study presents a groundbreaking solution-an electro-free and point-of-care (POC) tool known as the field-LAMP assay-for the rapid clinical detection of CSFV. By eliminating the RNA extraction requirement, advancing the colorimetric read-out and lyophilized reaction reagents, our field-LAMP assay streamlines the diagnostic process, saving valuable time and effort. This novel approach also overcomes the dependency on electric-dependent thermal incubators and expensive micropipettes, making it practical and accessible for use in the field. The successful development of the field-LAMP assay marks a significant milestone in CSFV detection. This electro-free and POC tool offers several advantages, including its ability to deliver rapid results without compromising accuracy, facilitating prompt response and containment measures.


Asunto(s)
Virus de la Fiebre Porcina Clásica , Peste Porcina Clásica , Enfermedades de los Porcinos , Porcinos , Animales , ARN , Sensibilidad y Especificidad , Peste Porcina Clásica/diagnóstico , ARN Viral , Enfermedades de los Porcinos/diagnóstico
4.
Chemosphere ; 349: 140797, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38016526

RESUMEN

Arsenic (As) turnover in rice paddy agro-ecosystems has received much attention because As can enter the food chain through its accumulation in rice, thereby affecting human health. Returning straw to soil is a common practice to retain nutrients for soil and crops, but it also cycles As within the rice paddy field ecosystems. However, there is still a lack of detailed understanding of the fate of As in rice straw, and how or to what extent it is recycled back into the soil environment. This study aims to elucidate the relationship between the microstructure of rice straw and the release of As during rice straw decomposition. The microstructure of rice straw was found to comprise both organic and silica (phytolith) components. These two constituents are inter-embedded to form a composite-like structure that contains up to 6.48 mg As Kg-1. The 30-day batch experiments revealed that the biochemical release of As simultaneously depends upon the decomposition of the organic component and the desilicification of the silica component. Accompanying the release of As was the release of other elements such as Fe, Al, P and S. These elements can further interact with As to form less mobile compounds. The introduction of either Trichoderma harzianum or Bacillus velezensis was expected to accelerate the decomposition of rice straw, and enhance the silica dissolution, hence contributing to an increase in the As release. Despite these expectations, our observations showed the opposite effects. Microorganisms presumably have facilitated the change in solution chemistry or the inclusion of As into the newly-formed precipitates. The biochemical decomposition process can reduce straw particle size, while the negatively-charge surface will involve microsized straw particles in the electrostatic interaction, thereby favoring the dispersibility state. Therefore, the co-transport of micro-sized straw particles with As under field conditions should not be neglected.


Asunto(s)
Arsénico , Oryza , Humanos , Oryza/química , Ecosistema , Suelo/química , Dióxido de Silicio
5.
Nano Lett ; 11(11): 4800-4, 2011 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-22007874

RESUMEN

We perform transmission electron microscopy, electron diffraction, and Raman scattering experiments on an individual suspended double-walled carbon nanotube (DWCNT). The first two techniques allow the unambiguous determination of the DWCNT structure: (12,8)@(16,14). However, the low-frequency features in the Raman spectra cannot be connected to the derived layer diameters d by means of the 1/d power law, widely used for the diameter dependence of the radial-breathing mode of single-walled nanotubes. We discuss this disagreement in terms of mechanical coupling between the layers of the DWCNT, which results in collective vibrational modes. Theoretical predictions for the breathing-like modes of the DWCNT, originating from the radial-breathing modes of the layers, are in a very good agreement with the observed Raman spectra. Moreover, the mechanical coupling qualitatively explains the observation of Raman lines of breathing-like modes, whenever only one of the layers is in resonance with the laser energy.


Asunto(s)
Nanoestructuras/química , Nanoestructuras/ultraestructura , Adhesividad , Ensayo de Materiales , Tamaño de la Partícula , Estrés Mecánico , Resistencia a la Tracción
6.
Med J Malaysia ; 67(6): 571-6, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23770947

RESUMEN

INTRODUCTION: Our study was to examine prevalence and treatment outcomes of medical emergencies at two urban public health clinics in the Petaling district, Selangor, Malaysia. METHODS: A prospective universal sampling was employed to recruit all emergencies over one month period (12 April to 11 May 2011). A structured case record form was used to capture demographic data, whether the index case was selfpresenting or decided by health care workers as a medical emergency, presenting complaints, diagnoses, concurrent chronic diseases and their treatment outcomes at the clinic level. Emergency presentations and diagnoses were classified according to the International Classification of Primary Care, revised second edition (ICPC-2-R). RESULTS: A total of 125 medical emergencies with 276 presenting complaints were recorded. The mean age was 30.7 years old (SD 19.9). The prevalence of medical emergency was 0.56% (125/22,320). Chief complaints were mainly from ICPC-2-R chapter R (respiratory system) and chapter A (general and unspecified), 40.0% and 28.0% respectively. The most common diagnosis was acute exacerbation of bronchial asthma (34.6%). Forty percent were referred to hospitals. After adjusting for age and gender, patients who presented with painful emergency (OR 4.9 95% CI 2.0 to 11.7), cardiovascular emergency (OR 63.4 95% CI 12.9 to 310.4) and non-respiratory emergency were predictors of hospital referral (OR 4.6 95% CI 1.1 to 19.1). CONCLUSION: There was about one medical emergency for every 200 patients presenting to these urban public polyclinics which were mainly acute asthma. More than half were discharged well and given a follow-up.


Asunto(s)
Urgencias Médicas , Salud Pública , Asma , Servicio de Urgencia en Hospital , Humanos , Estudios Prospectivos , Resultado del Tratamiento
7.
Animal ; 14(6): 1167-1175, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31907083

RESUMEN

To reduce competition with human-edible feed resources, it is of interest to incorporate by-products from the food industry in animal feeds. The current research investigated the effect of including increasing amounts of tofu by-product (TF) in practical pig diets on animal performance, nitrogen balance and ammonia emissions from manure. Two experiments were conducted including a control diet without TF, containing 160 g/kg dietary non-starch polysaccharides (NSPs) and three diets including 122, 246 and 360 g TF/kg DM (TF122, TF246 and TF360, respectively) to reach 220, 280 and 360 g/kg NSP. All diets had the same level of CP and protein digestible in the small intestine which particularly was realized by replacing rice bran with TF. Animal performance was assessed in a first experiment with 40 growing barrows with initial BW of 26.6 ± 1.80 kg (M ± SD) being allocated to the 4 treatments, during 2 growth phases (i.e. until 50 kg BW and from 50 to 80 kg BW). In the growth phase until 50 kg, feed intake and average daily gain (ADG) were linearly reduced by dietary TF inclusion, while this negative impact disappeared during the second growth phase (50 to 80 kg BW). Tofu by-product inclusion even positively affected the feed conversion ratio during this second growth phase (3.4 to 2.7 kg feed/kg ADG for 0 to 360 g/kg dietary TF). Over the entire growth period, performance and feed intake were negatively affected at the highest dietary TF level. Experiment 2 was conducted to assess digestibility, nitrogen balance and ammonia emission from manure. For this purpose, 16 pigs with BW of 62.8 ± 3.6 kg (M ± SD) were assigned to either 1 of the 4 treatments. There was no difference in total tract apparent digestibility of dietary organic matter or CP, while NDF digestibility increased with increasing TF level, suggesting increasing importance of the hindgut fermentation when digesting diets with increasing TF levels. Nevertheless, this was not reflected in increasing levels of faecal volatile fatty acids or purines, nor in reduced manure pH. As a result, ammonia emission from slurry was not reduced through dietary TF inclusion, despite the linear decrease in urinary nitrogen. In conclusion, TF can be included in pigs' diets up to an inclusion rate of 25% without risk of impaired animal performance; however, this dietary strategy fails to mitigate ammonia emission from slurry.


Asunto(s)
Amoníaco/metabolismo , Ácidos Grasos Volátiles/metabolismo , Nitrógeno/metabolismo , Alimentos de Soja/análisis , Porcinos/fisiología , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Digestión , Heces/química , Fermentación , Tracto Gastrointestinal/fisiología , Masculino , Estiércol/análisis
8.
J Environ Qual ; 48(3): 670-676, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31180432

RESUMEN

Silicic acid and soluble Fe are among the most abundant components in acid mine drainage. During the oxidation of Fe(II), the interaction between silicic acid and freshly formed Fe oxides might change the colloidal dynamics, altering surface charge properties. However, the effects of silicic acid on colloidal Fe oxides formed from acid mine drainage are not fully understood. In this work, we examined the colloidal dynamics of freshly formed Fe oxides in synthetic acid mine drainage (prepared from FeSO solution) under the effect of silicic acid as a function of changes in pH and ionic strength. The results demonstrate that through adsorption, silicic acid progressively slows oxidation and enhances the dispersion of freshly formed Fe oxides by shifting the surface charge toward more negative values. This effect was most prominent between pH 5 and 9. The current results demonstrate that silicic acid enhances the dispersion and transport of freshly formed Fe oxides and suggest that aggregation-based techniques for the treatment of Fe-rich drainage may require further consideration of this effect.


Asunto(s)
Hierro , Ácido Silícico , Compuestos Férricos , Oxidación-Reducción , Óxidos
9.
Cancer Res ; 52(22): 6168-74, 1992 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-1423260

RESUMEN

Dissemination of tumor to the leptomeninges and cerebrospinal fluid represents a common pattern of metastasis for many cancers; however, few chemotherapeutic agents are available for intrathecal (i.t.) use and treatment results are often poor. We studied the neurotoxicity and pharmacokinetics of i.t. 4-hydroperoxycyclophosphamide (4-HC) in the rabbit and the activity of i.t. 4-HC in a VX2 rabbit model of leptomeningeal carcinomatosis to evaluate the potential use of 4-HC in the treatment of leptomeningeal tumors. Toxicity studies examined 4-HC doses ranging from 0.5 to 6.0 mumol administered by intraventricular injection weekly for 4 to 8 weeks. Clinical or histological neurotoxicity was not observed in rabbits treated with < 1.0 mumol 4-HC for 4 weeks. Clinical toxicity, characterized by lethargy, weight loss, seizures, or death, was apparent at doses > 2.0 mumol. Vasculitis of superficial arteries was observed in rabbits treated with > 1.0 mumol 4-HC. In cerebrospinal fluid pharmacokinetic studies, the mean drug half-life after intraventricular or intralumbar administration was 24.3 and 18.2 min. Regional inequities in drug exposure were apparent as area under the clearance curve values for cerebrospinal fluid distant from the injection site were lower than those of proximate sites (P < 0.001). Weekly intraventricular treatment of VX2 leptomeningeal tumor-bearing rabbits with 0.5 or 1.0 mumol of 4-HC resulted in an increased life span of 22.5 and 35%, respectively. These results indicate that i.t. 4-HC, at doses lower than those producing neurotoxicity in the rabbit, is effective treatment for VX2 leptomeningeal carcinomatosis.


Asunto(s)
Ciclofosfamida/análogos & derivados , Neoplasias Meníngeas/tratamiento farmacológico , Enfermedades del Sistema Nervioso/inducido químicamente , Animales , Aracnoides/patología , Conducta Animal/efectos de los fármacos , Ciclofosfamida/farmacocinética , Ciclofosfamida/farmacología , Ciclofosfamida/toxicidad , Modelos Animales de Enfermedad , Inyecciones Espinales , Masculino , Neoplasias Meníngeas/patología , Enfermedades del Sistema Nervioso/patología , Piamadre/patología , Conejos
10.
Zoonoses Public Health ; 63(7): 569-576, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-26952244

RESUMEN

This study was conducted to estimate the prevalence of Salmonella spp. and their antimicrobial susceptibilities on poultry and swine farms, sampled in 2 regions in Central Vietnam. A total of 67 poultry farms and 46 swine farms were sampled in a period of 5 months (from September 2012 to January 2013). Salmonella spp. was prevalent in 46.3% and 71.7% of poultry and swine farms, respectively. Altogether, 99 non-typhoidal Salmonella were isolated and the most common serovars were Salmonella Weltevreden (19%), followed by Salmonella Typhimurium (12%) and Salmonella 4,[5],12:i:- (11%). Overall, 71 of 99 (72%) Salmonella isolates were resistant to at least one of the 14 antimicrobial agents tested. Both in poultry and swine farms, high levels of resistance were observed for ampicillin, chloramphenicol, ciprofloxacin, sulphamethoxazole and tetracycline. The presence of Salmonella isolates from poultry and swine farms which were resistant to different classes of antimicrobials suggests that alternative control measures to antimicrobials should be implemented. Moreover, an effective policy should be promoted to encourage a prudent use of these agents in animal farming in Vietnam.


Asunto(s)
Antibacterianos/farmacología , Pollos , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/microbiología , Salmonella/clasificación , Enfermedades de los Porcinos/microbiología , Animales , Farmacorresistencia Bacteriana , Vivienda para Animales , Enfermedades de las Aves de Corral/epidemiología , Salmonella/efectos de los fármacos , Salmonella/aislamiento & purificación , Salmonelosis Animal/epidemiología , Porcinos , Enfermedades de los Porcinos/epidemiología , Vietnam
11.
J Leukoc Biol ; 67(1): 46-52, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10647997

RESUMEN

Monochloramine derivatives are physiological oxidants produced by activated neutrophils. We report the effects of chemically prepared monochloramine (NH2Cl) on Fas-induced apoptosis in Jurkat T cells. When the cells were pretreated with NH2Cl (20-70 microM), subsequent addition of apoptosis-inducing anti-Fas antibody resulted in a synergistic enhancement of apoptosis. Treatment of NH2Cl (50-70 microM) alone resulted in a slight but definite apoptosis. Caspase activities, as measured by DEVD and IETD cleavage activities, were also elevated synergistically by NH2Cl + anti-Fas antibody stimulation. Moreover, a broad caspase inhibitor, Z-VAD-fmk, almost completely inhibited the apoptosis induced by NH2Cl and/or anti-Fas antibody. Fas expression on the Jurkat cell surface was not affected by the NH2Cl treatment. After 3 h of NH2Cl treatment, when the apoptosis was beginning to increase, the cells showed cytochrome c release from mitochondria, proteolytic activation of caspase 9, and poly (ADP-ribose) polymerase cleavage, regardless of Fas stimulation. Z-VAD-fmk almost completely inhibited this poly (ADP-ribose) polymerase cleavage, but not cytochrome c release. By contrast, Fas stimulation alone resulted in neither cytochrome c release nor caspase 9 activation at 3 h, and the increase in the DEVD cleavage activity and apoptosis became evident at later time points. These results suggested that NH2Cl enhanced Fas-induced apoptosis through the cytochrome c release and caspase 9 activation at the early stage of apoptosis. Chloramines derived from acute inflammation may modify immune reactions, such as cell-mediated cytotoxicity and some autoimmune diseases, by the enhancement of Fas-induced apoptosis.


Asunto(s)
Apoptosis/efectos de los fármacos , Cloraminas/farmacología , Linfocitos T/patología , Receptor fas/inmunología , Apoptosis/inmunología , Humanos , Células Jurkat , Transducción de Señal/efectos de los fármacos , Linfocitos T/inmunología
12.
J Neuropathol Exp Neurol ; 46(2): 223-31, 1987 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-3546601

RESUMEN

The following report using light and electron microscopic and immunological techniques is based on a series of 19 Burmese patients who died of cerebral malaria. The principal change was blockage of cerebral capillaries by Plasmodium falciparum-infected erythrocytes. Ring hemorrhages and segmental necrosis of cerebral capillaries were common. Cerebral edema was variable in these cases. Electron-dense knobs, 40 X 80 nm in size, which protruded from the membrane of infected erythrocytes, formed focal junctions between endothelial cells and erythrocytes. These junctions resulted in the entrapment of erythrocytes and caused blockage in the capillary lumen. Immunoperoxidase study revealed that P. falciparum antigens and IgG deposits in the capillary basement membrane. This implies that damage to the cerebral capillary could be related to immune mechanisms.


Asunto(s)
Encefalopatías/patología , Malaria/patología , Adolescente , Adulto , Membrana Basal/metabolismo , Membrana Basal/parasitología , Encéfalo/parasitología , Encéfalo/patología , Encéfalo/ultraestructura , Encefalopatías/parasitología , Niño , Preescolar , Femenino , Humanos , Inmunoglobulina G/metabolismo , Malaria/parasitología , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Plasmodium falciparum/aislamiento & purificación
13.
Free Radic Biol Med ; 30(8): 932-40, 2001 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-11295536

RESUMEN

Monochloramine (NH(2)Cl) is a physiological oxidant produced by activated neutrophils, and it affects apoptosis signaling. We studied the effects of NH(2)Cl on the cell death induced by etoposide, a widely used anticancer agent that is directed to DNA topoisomerase II. Jurkat T cells, a human acute T cell leukemia cell line, were pretreated with 70 microM of NH(2)Cl for 10 min. After 24 h, 5-30 microM of etoposide was added to the NH(2)Cl pretreated and control cells, and their apoptosis, caspase activity, cell morphology, and cellular DNA contents were measured. NH(2)Cl pretreatment significantly inhibited apoptosis and caspase activation induced by etoposide or camptothecin, a DNA topoisomerase I poison, but not by staurosporine or Fas stimulation. The apoptosis inhibition actually resulted in the proliferation of the survived cells and, notably, the survived cells showed more aberrant morphology, such as variation in nuclear size, nuclear fragments, and multinucleated cells. DNA content analysis of the survived cells showed an increase in aneuploid nuclei. Cell cycle analysis after 24 h of NH(2)Cl treatment showed a significant decrease in S phase cells with a concurrent increase in G(0)/G(1) phase cells, which suggested that NH(2)Cl induced G(1) arrest. Using synchronized Jurkat cells, etoposide and camptothecin were found to be particularly cytotoxic to S phase cells, whereas staurosporine and Fas stimulation were not. Thus NH(2)Cl-induced G(1) arrest was a likely cause of the observed resistance to etoposide. These observations suggested that inflammation-derived oxidants may make the tumor cells more resistant to etoposide and increase the risk of tumor progression and the development of secondary tumors by increasing the survival of DNA damage-bearing cells.


Asunto(s)
Apoptosis/efectos de los fármacos , Cloraminas/farmacología , Daño del ADN/efectos de los fármacos , Etopósido/antagonistas & inhibidores , Oxidantes/farmacología , Aneuploidia , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales de Origen Murino , Antineoplásicos Fitogénicos/antagonistas & inhibidores , Antineoplásicos Fitogénicos/farmacología , Camptotecina/antagonistas & inhibidores , Camptotecina/farmacología , Caspasas/metabolismo , Ciclo Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Tamaño de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , ADN/análisis , Daño del ADN/genética , Activación Enzimática/efectos de los fármacos , Etopósido/farmacología , Humanos , Células Jurkat , Estaurosporina/farmacología
14.
Neurology ; 59(1): 40-8, 2002 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-12105305

RESUMEN

BACKGROUND: Assumptions about the damaging effects of radiotherapy (XRT) are based on studies in which total dose, dose fraction, treatment volume, degree of malignancy, chemotherapy, tumor recurrence, and neurologic comorbidity interact with XRT effects. This is a prospective, long-term study of XRT effects in adults, in which total dose and dose fraction were constrained and data related to tumor recurrence and neurologic comorbidity (e.g., hypertension) were excluded. METHODS: The effects of XRT on the cognitive and radiographic outcomes of 26 patients with low-grade, supratentorial, brain tumors yearly from baseline (6 weeks after surgery and immediately before XRT) and yearly to 6 years were examined. Radiographic findings were examined regionally. RESULTS: Selective cognitive declines (in visual memory) emerged only at 5 years, whereas ratings of clinical MRI (T2 images) showed mild accumulation of hyperintensities with post-treatment onset from 6 months to 3 years, with no further progression. White matter atrophy and total hyperintensities demonstrated this effect, with subcortical and deep white matter, corpus callosum, cerebellar structures, and pons accounting for these changes over time. About half of the patients demonstrated cognitive decline and treatment-related hyperintensities. CONCLUSIONS: There was no evidence of a general cognitive decline or progression of white matter changes after 3 years. Results argue for limited damage from XRT at this frequently used dose and volume in the absence of other clinical risk factors.


Asunto(s)
Trastornos del Conocimiento/etiología , Radioterapia/efectos adversos , Neoplasias Supratentoriales/radioterapia , Adulto , Corteza Cerebral/patología , Trastornos del Conocimiento/patología , Depresión/diagnóstico , Fatiga/diagnóstico , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Pruebas Neuropsicológicas , Estudios Prospectivos , Dosificación Radioterapéutica , Neoplasias Supratentoriales/mortalidad , Neoplasias Supratentoriales/patología
15.
J Med Chem ; 44(12): 1986-92, 2001 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-11384243

RESUMEN

The prevention of xenograft rejection is substantially dependent on inhibiting antibodies (Ab) produced by B-cells independently of T-cell signals (TI-1). Due to their ubiquitous biochemical mechanisms of action, the immunosuppressants currently employed not only fail to discriminate between B- and T-cells but also have a narrow therapeutic window and, thus, their prolonged use in complex immunosuppressive regimens is problematic. By capitalizing on the target enzyme-bound (DHODH) structure 1b of one of these compounds, leflunomide, and modulating part of its multiple mechanisms of action to gain selectivity, the quinoline-8-carboxamide 3 was designed as a potentially weak enzyme inhibitor but effective immunosuppressant. Compound 3 fulfilled the mechanistic criteria set and had 10-fold B-cell over T-cell selectivity. Its pyridyl analogue 4 was found to be a highly potent and selective B-cell immunosuppressant with a 75-fold selectivity for B- over T-cells (as judged by the MLR data) and no general cytotoxicity at concentrations up to 160-fold higher than those required to inhibit B-cells. In the mouse, 4 effectively blocked TI-1 Ab production and suppressed Ab-mediated xenograft rejection in a xenotransplantation model under a once-daily dosing regimen, with efficacy down to 0.3 mg/kg/day po. These are the first data demonstrating the feasibility of the development of drugs specific for impeding Ab production.


Asunto(s)
Linfocitos B/efectos de los fármacos , Rechazo de Injerto/prevención & control , Inmunosupresores/síntesis química , Quinolinas/síntesis química , Trasplante Heterólogo/inmunología , Animales , Formación de Anticuerpos/efectos de los fármacos , Linfocitos B/inmunología , Cricetinae , Diseño de Fármacos , Supervivencia de Injerto/efectos de los fármacos , Trasplante de Corazón/inmunología , Inmunosupresores/sangre , Inmunosupresores/química , Inmunosupresores/farmacología , Lipopolisacáridos/farmacología , Mesocricetus , Ratones , Ratones Desnudos , Modelos Moleculares , Conformación Molecular , Quinolinas/química , Quinolinas/farmacocinética , Quinolinas/farmacología , Relación Estructura-Actividad , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología
16.
Physiol Behav ; 56(2): 237-9, 1994 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7938232

RESUMEN

Sucrose thresholds were measured at three points during the menstrual cycle for 14 women who were not taking oral contraceptives. Thirteen men also were tested at similar intervals. Sucrose thresholds of the men remained constant throughout the experiment. During menstruation and postovulation, the thresholds of the women were similar to the thresholds of the men, whereas during preovulation the thresholds of the women are significantly lower. The stable sucrose thresholds of the men suggest that ovarian hormones may be involved in the variation in sucrose sucrose thresholds of the women. The increase in sensitivity of the women during preovulation may have been related to the high level of estrogen, whereas the decrease in sensitivity during postovulation may be due to some type of interaction between estrogen and progesterone.


Asunto(s)
Preferencias Alimentarias/fisiología , Ciclo Menstrual/fisiología , Umbral Gustativo/fisiología , Adolescente , Adulto , Estrógenos/fisiología , Femenino , Humanos , Masculino , Progesterona/fisiología , Sacarosa
17.
Artículo en Inglés | MEDLINE | ID: mdl-11939545

RESUMEN

A mathematical model was developed for the study of the D,L-dansylamino acid retention mechanism in reversed-phase liquid chromatography using a C18 column as a stationary phase and human serum albumin (HSA) as an eluent modifier. The solute retention factor is dependent on the HSA concentration in the eluent as well as the binding constant of the guest-HSA complex. A determination of the degree of complexation n(c) (the percent of the complexed guest) could be carried out. Different Van 't Hoff plot shapes of the degree of complexation were observed with different eluent pH, confirming a change in the solute complexation mechanism for physiological pH (between 7-7.5). Enthalpy-entropy compensation was also analysed in relation to this mathematical model to confirm the solute complexation behavior with HSA. These results finally confirmed that at physiological pH and temperature (approximately 35 degrees C) values the HSA was in a favorable structural conformation for its binding with a great majority of drugs.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Albúmina Sérica/química , Humanos , Concentración de Iones de Hidrógeno , Reproducibilidad de los Resultados , Espectrofotometría Ultravioleta , Temperatura , Termodinámica
18.
Am J Geriatr Cardiol ; 12(2): 107-9, 112, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12624580

RESUMEN

The authors reviewed all negative preoperative dobutamine stress echocardiograms (DSEs) performed over a 3-year period to determine the value of negative DSE for preoperative risk assessment in elderly patients. All patients with negative DSE performed for preoperative evaluation were followed. Cardiac event rates during and after the operative procedure were determined for hard end points (nonfatal myocardial infarction, cardiac death) and soft end points (emergency room visits, hospitalization for unstable angina, congestive heart failure, coronary angioplasty, coronary artery bypass graft surgery). Results noted that DSEs were negative for ischemia in 82 preoperative evaluations. Group 1 (age >/=65; n=41) had hard and soft event rates per patient/year of 0.97% and 7.3%, while group 2 (age <65; n=41) had hard and soft event rates per patient/year of 0.81% and 10.8%. There were no significant differences in event rates between the two groups (p=NS). In conclusion, the authors found that negative DSEs predict low cardiac event rates in elderly patients during the perioperative and long-term postoperative periods, which are not significantly different from the cardiac event rates in a younger cohort.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Ecocardiografía de Estrés , Cardiopatías/diagnóstico , Cardiopatías/cirugía , Cuidados Posoperatorios , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/etiología , Cuidados Preoperatorios , Anciano , California/epidemiología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Cardiopatías/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/epidemiología , Medición de Riesgo , Factores de Riesgo , Tiempo , Resultado del Tratamiento
19.
J Laryngol Otol ; 113(1): 79-81, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10341929

RESUMEN

We report a case of verruciform xanthoma of the nasal skin. The case is unique because the lesion both bled and has shown evidence of multicentricity.


Asunto(s)
Enfermedades Nasales/patología , Xantomatosis/patología , Adulto , Femenino , Humanos , Enfermedades Nasales/cirugía , Xantomatosis/cirugía
20.
Southeast Asian J Trop Med Public Health ; 24(1): 198-201, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8362297

RESUMEN

Serum and urine concentrations of fibrin (-ogen) degradation products (FDP) were estimated in 20 proven Russell's viper bite (RVB) cases with severe defribination. All patients had similar degrees of high serum FDP levels. However, the ten who developed into acute renal failure (ARF) had significantly (p < 0.001) higher urinary FDP levels than those who did not. The urinary FDP levels of ARF cases increased correspondingly with high serum FDP levels but not in cases without ARF. Serial comparison of serum and urinary FDP levels in RVB cases with severe defibrination may be of value in predicting the likelihood of developing ARF. The present study favored disseminated intravascular coagulation as the main cause of ARF in Myanmar RVB cases.


Asunto(s)
Productos de Degradación de Fibrina-Fibrinógeno/orina , Mordeduras de Serpientes/orina , Humanos , Insuficiencia Renal/etiología , Insuficiencia Renal/orina , Venenos de Víboras/toxicidad
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