RESUMO
BACKGROUND: Serum vitamin D level shows a seasonal variation, being lower in winter than in summer in healthy subjects. The aim of this study was to determine whether there is presence of such a seasonal variation in hemodialysis patients. METHODS: A total of 102 patients on hemodialysis were enrolled in February 2017 (winter) for analyses of serum levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] and treatments for chronic kidney disease-mineral and bone disorder (CKD-MBD). The examinations were repeated in August 2017 (summer). After exclusion of patients with malignancy, loss of follow-up and missing data, 78 patients contributed to the analyses. RESULTS: Serum level of 25(OH)D, but not that of 1,25(OH)2D, was significantly lower in winter (14.0 ng/mL) than in summer (15.5 ng/mL), though there was no significant difference in regimen for CKD-MBD treatment including vitamin D receptor activators (VDRAs) between the two seasons. Serum intact parathyroid hormone level tended to be higher and alkaline phosphatase was significantly higher in winter than in summer. Linear mixed-effects model analysis showed that level of 25(OH)D, but not that of 1,25(OH)2D, was significantly associated with season (winter and summer) after adjustment of age, sex, dialysis vintage, albumin level and use of drugs for CKD-MBD. CONCLUSION: Serum 25(OH)D has a seasonal variation, being lower in winter than in summer, independent of CKD-MBD treatment including treatment with VDRAs in Japanese hemodialysis patients. The impact of the seasonal variation on risk of vitamin D deficiency and its effect on prognosis remain to be investigated.
Assuntos
Nefropatias/terapia , Diálise Renal , Estações do Ano , Deficiência de Vitamina D/sangue , Vitamina D/análogos & derivados , Idoso , Biomarcadores/sangue , Feminino , Humanos , Japão , Nefropatias/sangue , Nefropatias/diagnóstico , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Vitamina D/sangue , Deficiência de Vitamina D/diagnósticoRESUMO
Four new bromotyrosine alkaloids, tyrokeradines C-F (1-4), have been isolated from Okinawan marine sponges of the order Verongidae. The structures of 1-4 were elucidated on the basis of spectroscopic data. Tyrokeradines C (1) and D (2) are new bromotyrosine alkaloids possesing an imidazole ring, while tyrokeradines E (3) and F (4) are new bromotyrosine alkaloids possesing a cyano group.
Assuntos
Alcaloides/isolamento & purificação , Poríferos/química , Tirosina/análogos & derivados , Alcaloides/química , Animais , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Tirosina/química , Tirosina/isolamento & purificaçãoRESUMO
Two new bromotyrosine alkaloids, tyrokeradines A (1) and B (2), with an imidazolyl-quinolinone moiety have been isolated from an Okinawan marine sponge of the order Verongida. The structures of 1 and 2 were elucidated on the basis of spectroscopic data.