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1.
Science ; 385(6708): 517-521, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39088605

RESUMEN

Tropical glaciers have retreated over recent decades, but whether the magnitude of this retreat exceeds the bounds of Holocene fluctuations is unclear. We measured cosmogenic beryllium-10 and carbon-14 concentrations in recently exposed bedrock at the margin of four glaciers spanning the tropical Andes to reconstruct their past extents relative to today. Nuclide concentrations are near zero in almost all samples, suggesting that these locations were never exposed during the Holocene. Our data imply that many glaciers in the tropics are probably now smaller than they have been in at least 11,700 years, making the tropics the first large region where this milestone has been documented.

2.
J Antibiot (Tokyo) ; 59(9): 583-90, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17136890

RESUMEN

Structural features associated with the antimalarial activity of the marine natural product crambescidin 800 were studied using synthetic analogues of the related compound ptilomycalin A. The study suggests that the guanidine moiety is cytotoxic, whereas the spermidine-containing aliphatic chain increases activity. The most active analogue, compound 11, had in vitro activity against Plasmodium falciparum strain 3D7 (IC50=490 nM) that was stronger than the in vitro activity against murine L5178Y cells (IC50 = 8.5-59 microM). In vitro growth inhibition of liver stages of P. yoelii yoelii in mouse hepatocytes was observed (IC50 = 9.2 microM). The compound did not significantly prolong median survival time after a single subcutaneous administration of 80 mg/kg in P. berghei-infected mice. Compound 11 did not cause DNA fragmentation in an in vitro micronucleus assay.


Asunto(s)
Antimaláricos/química , Antimaláricos/farmacología , Guanidina/análogos & derivados , Malaria/tratamiento farmacológico , Plasmodium falciparum/efectos de los fármacos , Plasmodium yoelii/efectos de los fármacos , Compuestos de Espiro/química , Compuestos de Espiro/farmacología , Animales , Antimaláricos/toxicidad , Células Cultivadas , Modelos Animales de Enfermedad , Eritrocitos/parasitología , Guanidina/química , Guanidina/farmacología , Guanidina/toxicidad , Hepatocitos/parasitología , Ratones , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Compuestos de Espiro/toxicidad , Análisis de Supervivencia
3.
Ophthalmol Clin North Am ; 18(1): 119-28, ix, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15763197

RESUMEN

This article describes surgical methods for resecting uveal melanoma, emphasizing techniques for preventing complications. Outcomes of surgery and the indications, contraindications, and controversies of resecting uveal melanoma are discussed.


Asunto(s)
Melanoma/cirugía , Procedimientos Quirúrgicos Oftalmológicos/métodos , Neoplasias de la Úvea/cirugía , Anestesia/métodos , Humanos , Melanoma/patología , Complicaciones Posoperatorias/prevención & control , Pronóstico , Resultado del Tratamiento , Neoplasias de la Úvea/patología
4.
Hosp Med ; 63(2): 92-4, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11902095

RESUMEN

The use of profound induced hypotension to provide better operating conditions for surgery is long established. However, it is a controversial technique and it may be argued that it is inappropriate in modern anaesthetic practice. A currently used technique is reviewed against the benchmark of a lawsuit concerning profound hypotension.


Asunto(s)
Anestesia/métodos , Anestesiología/legislación & jurisprudencia , Ética Médica , Hipotensión Controlada , Mala Praxis , Humanos , Hipotensión Controlada/efectos adversos , Hipotensión Controlada/normas , Monitoreo Intraoperatorio/normas
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