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1.
Cleve Clin J Med ; 85(7): 543-550, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30004379

RESUMO

Calcium, a key component of bone, is obtained through diet or supplements, or both, and vitamin D is necessary for normal calcium absorption. Controversy exists as to the efficacy and even the safety of calcium. Our opinion, backed by studies and guidelines, is that adequate amounts of calcium are a must for patients concerned about bone health, and cardiovascular safety is not a concern.


Assuntos
Cálcio da Dieta/administração & dosagem , Vitamina D/administração & dosagem , Densidade Óssea/fisiologia , Cálcio da Dieta/efeitos adversos , Dieta , Suplementos Nutricionais , Humanos
2.
J Clin Densitom ; 21(1): 125-129, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-27422238

RESUMO

The International Society for Clinical Densitometry guidelines recommend using locally derived precision data for spine bone mineral densities (BMDs), but do not specify whether data derived from L1-L4 spines correctly reflect the precision for spines reporting fewer than 4 vertebrae. Our experience suggested that the decrease in precision with successively fewer vertebrae is progressive as more vertebrae are excluded and that the precision for the newer Horizon Hologic model might be better than that for the previous model, and we sought to quantify. Precision studies were performed on Hologic densitometers by acquiring spine BMD in fast array mode twice on 30 patients, according to International Society for Clinical Densitometry guidelines. This was done 10 different times on various Discovery densitometers, and once on a Horizon densitometer. When 1 vertebral body was excluded from analysis, there was no significant deterioration in precision. When 2 vertebrae were excluded, there was a nonsignificant trend to poorer precision, and when 3 vertebrae were excluded, there was significantly worse precision. When 3 or 4 vertebrae were reported, the precision of the spine BMD measurement was significantly better on the Hologic Horizon than on the Discovery, but the difference in precision between densitometers narrowed and was no longer significant when 1 or 2 vertebrae were reported. The results suggest that (1) the measurement of in vivo spine BMD on the new Hologic Horizon densitometer is significantly more precise than on the older Discovery model; (2) the difference in precision between the Horizon and Discovery models decreases as fewer vertebrae are included; (3) the measurement of spine BMD is less precise as more vertebrae are excluded, but still quite reasonable even when only 1 vertebral body is included; and (4) when 3 vertebrae are reported, L1-L4 precision data can reasonably be used to report significance of changes in BMD. When 1 or 2 vertebrae are reported, precision data for 1 or 2 vertebrae, respectively, should be used, because the exclusion of 2-3 vertebrae significantly worsens precision.


Assuntos
Absorciometria de Fóton/instrumentação , Densidade Óssea , Vértebras Lombares/diagnóstico por imagem , Absorciometria de Fóton/normas , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Reprodutibilidade dos Testes
3.
Proc Natl Acad Sci U S A ; 110(9): E818-27, 2013 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-23382191

RESUMO

Leptin is an adipocyte-derived hormone that controls food intake and reproductive and immune functions in rodents. In uncontrolled human studies, low leptin levels are associated with impaired immune responses and reduced T-cell counts; however, the effects of leptin replacement on the adaptive immune system have not yet been reported in the context of randomized, controlled studies and/or in conditions of chronic acquired leptin deficiency. To address these questions, we performed a randomized, double-blinded, placebo-controlled trial of recombinant methionyl-human leptin (metreleptin) administration in replacement doses in women experiencing the female triad (hypothalamic amenorrhea) with acquired chronic hypoleptinemia induced by negative energy balance. Metreleptin restored both CD4(+) T-cell counts and their in vitro proliferative responses in these women. These changes were accompanied by a transcriptional signature in which genes relevant to cell survival and hormonal response were up-regulated, and apoptosis genes were down-regulated in circulating immune cells. We also observed that signaling pathways involved in cell growth/survival/proliferation, such as the STAT3, AMPK, mTOR, ERK1/2, and Akt pathways, were activated directly by acute in vivo metreleptin administration in peripheral blood mononuclear cells and CD4(+) T-cells both from subjects with chronic hypoleptinemia and from normoleptinemic, lean female subjects. Our data show that metreleptin administration, in doses that normalize circulating leptin levels, induces transcriptional changes, activates intracellular signaling pathways, and restores CD4(+) T-cell counts. Thus, metreleptin may prove to be a safe and effective therapy for selective CD4(+) T-cell immune reconstitution in hypoleptinemic states such as tuberculosis and HIV infection in which CD4(+) T cells are reduced.


Assuntos
Linfócitos T CD4-Positivos/citologia , Leptina/análogos & derivados , Leptina/deficiência , Doenças Metabólicas/tratamento farmacológico , Doenças Metabólicas/imunologia , Adolescente , Adulto , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células/efeitos dos fármacos , Citocinas/biossíntese , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Feminino , Perfilação da Expressão Gênica , Hormônios/sangue , Humanos , Inflamação/sangue , Leptina/administração & dosagem , Leptina/sangue , Leptina/farmacologia , Leptina/uso terapêutico , Doenças Metabólicas/sangue , Doenças Metabólicas/patologia , Fenótipo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transcrição Gênica/efeitos dos fármacos , Resultado do Tratamento , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , Adulto Jovem
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