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1.
J Steroid Biochem Mol Biol ; 185: 248-250, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30244048

RESUMO

As part of our program on synthesis of labeled vitamin D metabolites and analogs, we describe here an efficient and versatile synthetic approach to 28,28,28-trideutero- 25-hydroxydihydrotachysterol2 where isotopic labeling was incorporated stereoselectively in the last step of the synthesis. This deuterated compound will allow the study this analog in vitro or in vivo and to measure AT10-like compounds in serum by LC-MS/MS.


Assuntos
Di-Hidrotaquisterol/análogos & derivados , Di-Hidrotaquisterol/análise , Di-Hidrotaquisterol/química , Vitamina D/análogos & derivados , Vitamina D/metabolismo , Deutério/química , Di-Hidrotaquisterol/síntese química , Coloração e Rotulagem , Vitamina D/química
2.
Nephrol Ther ; 14(4): 231-236, 2018 Jun.
Artigo em Francês | MEDLINE | ID: mdl-29709532

RESUMO

INTRODUCTION: Hypercalcemia is not a rare event and can lead to severe consequences. Its main etiologies are primary hyperparathyroidism and neoplasic conditions. The iatrogenic etiology by vitamin D intoxication is more rarely found. CASE PRESENTATION: A 76-year-old finish woman comes to the emergency room for chest pain. Her medical history is impossible to specify due to the language barrier and initial confusion. She has severe hypercalcaemia (4.14mmol/L), renal insufficiency, cardiac arrhythmia later complicated by an ischemic cardiac episode. Clinic and biologic examinations initially guided the research towards a hematological and neoplasic pathology. The iatrogenic etiology will be permitted by the contribution of details on its medical history and treatment learnt secondly. She was treated for post-surgical hypoparathyroidism by dihydrotachysterol, a vitamin D derivative. The cessation of substitution, treatment with hydration and biphosphonates allowed the rapid correction of hypercalcemia. DISCUSSION: Dihydrotachysterol intoxication is a rare etiology of hypercalcemia. Because of the longer half-life of this molecule, the risk of hypercalcemia seems to be greater than with other vitamin D derivatives. This molecule, withdrawn from the French market in 1982, is not detected by the dosage of 25 and 1.25 OH vitamin D. CONCLUSION: We report an original case of intoxication by dihydrotachysterol. The risk of hypercalcemia encountered with this molecule must be known. The close medical follow-up recommended in case of hypoparathyroidism seems to be particularly necessary in case of supplementation by this molecule.


Assuntos
Di-Hidrotaquisterol/envenenamento , Hipercalcemia/etiologia , Vitamina D/envenenamento , Idoso , Cálcio/sangue , Difosfonatos/uso terapêutico , Feminino , Hidratação/métodos , Humanos , Hipercalcemia/terapia , Hipoparatireoidismo/tratamento farmacológico , Doença Iatrogênica
3.
Biochem Biophys Res Commun ; 491(2): 361-367, 2017 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-28728841

RESUMO

Although several etiological factors contribute to the complexity of the aging process, the ultimate component of macromolecular damage and consequent cell death involves the altered redox balance inclined towards increased ROS production and/or decreased antioxidant protection. Given that, the chronic dihydrotachysterol (DHT) intoxication in rats induce Hutchinson Gilford progeria like syndrome, the present study provides the evidence for altered redox balance as evidenced by alteration in parameters of oxidative stress in blood plasma and erythrocytes including MDA, GSH, FRAP AOPP PMRS, AGEs, AChE and osmotic fragility which substantiate the suitability of the model for aging studies.


Assuntos
Envelhecimento/metabolismo , Antioxidantes/metabolismo , Eritrócitos/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Progéria/sangue , Espécies Reativas de Oxigênio/sangue , Acetilcolinesterase/sangue , Produtos da Oxidação Avançada de Proteínas/sangue , Envelhecimento/efeitos dos fármacos , Envelhecimento/patologia , Animais , Di-Hidrotaquisterol , Modelos Animais de Doenças , Eritrócitos/metabolismo , Feminino , Proteínas Ligadas por GPI/sangue , Glutationa/sangue , Humanos , Malondialdeído/sangue , Estresse Oxidativo , Progéria/induzido quimicamente , Progéria/patologia , Ratos , Ratos Wistar
4.
Kidney Int ; 91(5): 1070-1087, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28139295

RESUMO

Hypercalcemia can cause renal dysfunction such as nephrogenic diabetes insipidus (NDI), but the mechanisms underlying hypercalcemia-induced NDI are not well understood. To elucidate the early molecular changes responsible for this disorder, we employed mass spectrometry-based proteomic analysis of inner medullary collecting ducts (IMCD) isolated from parathyroid hormone-treated rats at onset of hypercalcemia-induced NDI. Forty-one proteins, including the water channel aquaporin-2, exhibited significant changes in abundance, most of which were decreased. Bioinformatic analysis revealed that many of the downregulated proteins were associated with cytoskeletal protein binding, regulation of actin filament polymerization, and cell-cell junctions. Targeted LC-MS/MS and immunoblot studies confirmed the downregulation of 16 proteins identified in the initial proteomic analysis and in additional experiments using a vitamin D treatment model of hypercalcemia-induced NDI. Evaluation of transcript levels and estimated half-life of the downregulated proteins suggested enhanced protein degradation as the possible regulatory mechanism. Electron microscopy showed defective intercellular junctions and autophagy in the IMCD cells from both vitamin D- and parathyroid hormone-treated rats. A significant increase in the number of autophagosomes was confirmed by immunofluorescence labeling of LC3. Colocalization of LC3 and Lamp1 with aquaporin-2 and other downregulated proteins was found in both models. Immunogold electron microscopy revealed aquaporin-2 in autophagosomes in IMCD cells from both hypercalcemia models. Finally, parathyroid hormone withdrawal reversed the NDI phenotype, accompanied by termination of aquaporin-2 autophagic degradation and normalization of both nonphoshorylated and S256-phosphorylated aquaporin-2 levels. Thus, enhanced autophagic degradation of proteins plays an important role in the initial mechanism of hypercalcemic-induced NDI.


Assuntos
Aquaporina 2/metabolismo , Autofagia , Diabetes Insípido Nefrogênico/fisiopatologia , Hipercalcemia/complicações , Túbulos Renais Coletores/fisiopatologia , Animais , Cromatografia Líquida , Diabetes Insípido Nefrogênico/etiologia , Diabetes Insípido Nefrogênico/metabolismo , Di-Hidrotaquisterol/toxicidade , Modelos Animais de Doenças , Regulação para Baixo , Imunofluorescência , Meia-Vida , Humanos , Hipercalcemia/induzido quimicamente , Junções Intercelulares/metabolismo , Junções Intercelulares/ultraestrutura , Túbulos Renais Coletores/metabolismo , Glicoproteínas de Membrana Associadas ao Lisossomo/metabolismo , Masculino , Microscopia Imunoeletrônica , Proteínas Associadas aos Microtúbulos/metabolismo , Hormônio Paratireóideo/farmacologia , Fosforilação , Proteólise , Proteômica/métodos , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas em Tandem
5.
J Am Vet Med Assoc ; 245(4): 419-24, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25075826

RESUMO

CASE DESCRIPTION: A 4-year-old castrated male domestic ferret (Mustela putorius furo) was examined because of a 3-week history of intermittent seizures, signs of depression, hypocalcemia, and hyperphosphatemia. CLINICAL FINDINGS: Plasma biochemical analysis confirmed hyperphosphatemia (17.7 mg/dL) and low concentrations of total (4.3 mg/dL) and ionized (0.49 mmol/L) calcium. Serum parathyroid hormone concentration (2.30 pmol/L) was low or in the low part of the reference interval. TREATMENT AND OUTCOME: Calcium gluconate was administered (2.0 mg/kg/h [0.9 mg/lb/h], IV), followed by a transition to administration of calcium carbonate (53 mg/kg [24.1 mg/lb], PO, q 12 h) and dihydrotachysterol (0.02 mg/kg/d [0.009 mg/lb/d], PO). Attitude of the ferret improved and seizures ceased as blood calcium concentrations increased. The ferret was reexamined because of seizures approximately 1 year after oral maintenance administration of dihydrotachysterol and calcium was initiated. The ferret responded well to emergency and long-term treatment but then was lost to follow-up monitoring. The ferret died approximately 2 years after the initial evaluation and treatment. Hypertrophic cardiomyopathy was diagnosed during necropsy, but the parathyroid glands could not be identified. CLINICAL RELEVANCE: To the authors' knowledge, primary hypoparathyroidism has not previously been reported in a ferret. The condition should be considered for ferrets with hypocalcemia and hyperphosphatemia without azotemia. Treatment with dihydrotachysterol and oral supplementation of calcium appeared to be a viable option for long-term management.


Assuntos
Carbonato de Cálcio/uso terapêutico , Gluconato de Cálcio/uso terapêutico , Di-Hidrotaquisterol/uso terapêutico , Furões , Hipoparatireoidismo/veterinária , Vitaminas/uso terapêutico , Animais , Carbonato de Cálcio/administração & dosagem , Gluconato de Cálcio/administração & dosagem , Di-Hidrotaquisterol/administração & dosagem , Hipocalcemia/veterinária , Hipoparatireoidismo/sangue , Hipoparatireoidismo/tratamento farmacológico , Masculino , Vitaminas/administração & dosagem
6.
Respir Res ; 15: 53, 2014 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-24766747

RESUMO

OBJECTIVES: We aimed to explore the association between vitamin D levels and the severity, mortality and microbiological etiology of community-acquired pneumonia. METHODS: Vitamin D levels (both, the reservoir form 25-OH and the activated form 1,25-OH2) of 300 randomly selected patients with community-acquired pneumonia due to pre-specified pathogens included in the German competence network (CAPNETZ) study were measured. Prior to statistical analysis, values of 25-OH and 1,25-OH2 were power-transformed to achieve parametric distribution. All further analyses were performed with seasonally and age adjusted values. RESULTS: There was only a modest (Spearman Coefficient 0.38) positive correlation between 25-OH and 1,25-OH2. For 1,25-OH2 but not 25-OH, the general linear model revealed a significant inverse correlation between serum concentration and CURB score (p = 0.011). Liver and respiratory co-morbidity were associated with significantly lower 25-OH values and renal co-morbidity with significantly lower 1,25-OH2 values. No significant differences of 1,25-OH2 or 25-OH between different pathogens (influenza virus, Legionella spp., Streptococcus pneumoniae) were detected. CONCLUSION: For 1,25-OH2, we found a significant and independent (controlled for age, season and pathogen) negative correlation to pneumonia severity. Therefore, supplementation of non-activated vitamin D to protect from pneumonia may be non-sufficient in patients that have a decreased capacity to hydroxylate 25-OH to 1,25-OH2.


Assuntos
Di-Hidrotaquisterol/análogos & derivados , Pneumonia/sangue , Estações do Ano , Índice de Gravidade de Doença , Deficiência de Vitamina D/sangue , Adulto , Idoso , Biomarcadores/sangue , Estudos de Coortes , Infecções Comunitárias Adquiridas/sangue , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/epidemiologia , Estudos Transversais , Di-Hidrotaquisterol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia/diagnóstico , Pneumonia/epidemiologia , Estudos Prospectivos , Vitamina D/sangue , Deficiência de Vitamina D/diagnóstico , Deficiência de Vitamina D/epidemiologia
8.
Prostaglandins Other Lipid Mediat ; 99(1-2): 45-50, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22800939

RESUMO

The effect of tumor necrosis factor-alpha (TNF) on cyclooxygenase-2 (COX-2) expression in the renal outer medulla (OM) was determined in a model of dihydrotachysterol (DHT)-induced hypercalcemia. Increases in serum calcium and water intake were observed during ingestion of a DHT-containing diet in both wild type (WT) and TNF deficient mice (TNF(-/-)). Polyuria and a decrease in body weight were observed in response to DHT treatment in WT and TNF(-/-) mice. A transient elevation in urinary TNF was observed in WT mice treated with DHT. Moreover, increased urinary levels of prostaglandin E(2) (PGE(2)) and a corresponding increase in COX-2 expression in the OM were observed in WT mice fed DHT. Increased COX-2 expression was not observed in TNF(-/-) mice fed DHT, and the characteristics of PGE(2) synthesis were distinct from those in WT mice. This study demonstrates that COX-2 expression in the OM, secondary to hypercalemia, is TNF-dependent.


Assuntos
Ciclo-Oxigenase 2/biossíntese , Hipercalcemia/metabolismo , Medula Renal/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Animais , Di-Hidrotaquisterol , Hipercalcemia/induzido quimicamente , Masculino , Camundongos , Poliúria/induzido quimicamente , Fator de Necrose Tumoral alfa/deficiência , Fator de Necrose Tumoral alfa/urina
9.
Turk J Gastroenterol ; 22(2): 134-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21796548

RESUMO

BACKGROUND/AIMS: Helicobacter pylori-associated corpus atrophy and autoimmune gastric atrophy share similar histopathologic and clinical aspects. In our study, the relation between Helicobacter pylori and autoimmune gastritis was investigated. METHODS: Eighty-two consecutive histologically and serologically Helicobacter pylori-positive and 96 Helicobacter pylori-negative patients were enrolled in the study. All patients underwent diagnostic upper esophagogastroduodenal endoscopy. Three biopsy specimens from the antrum and corpus greater curvature were obtained for histologic evaluation. Serum samples were collected for detection of anti-parietal cell antibody, anti-Helicobacter pylori IgG and vitamin B12. Statistical analyses were determined with Student t-test and chi-square test. Statistical significance was determined with a p-value <0.05. RESULTS: Of 82 Helicobacter pylori-positive patients, 45 were female and 36 were male, with a mean age 45.1 ± 15.1. There was no significant difference in age, gender and corpus atrophy between the Helicobacter pylori-positive and -negative groups. Eleven Helicobacter pylori-positive patients (13.4%) and 14 (14.6%) Helicobacter pylori-negative patients were positive for anti-parietal cell antibody; the difference between the two groups was not statistically significant (p>0.05). Differences in esophagogastroduodenal endoscopy findings, antrum and corpus inflammation, antrum and corpus atrophy, and vitamin B12 levels were found to be insignificant between parietal cell antibody-positive and -negative groups (p>0.05). CONCLUSIONS: We did not find any relation between Helicobacter pylori infection and anti-parietal cell antibody, a marker of autoimmune gastritis. Long-term follow-up of Helicobacter pylori-infected patients and also determination of the relation between eradication of Helicobacter pylori and autoimmune atrophic gastritis are needed.


Assuntos
Doenças Autoimunes/epidemiologia , Gastrite/epidemiologia , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/imunologia , Adulto , Idoso , Anticorpos Antibacterianos/sangue , Autoanticorpos/sangue , Doenças Autoimunes/imunologia , Doenças Autoimunes/microbiologia , Estudos de Casos e Controles , Di-Hidrotaquisterol , Feminino , Mucosa Gástrica/imunologia , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Gastrite/imunologia , Gastrite/patologia , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/patologia , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Células Parietais Gástricas/imunologia , Células Parietais Gástricas/microbiologia , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Vitamina B 12/sangue
10.
Biophys J ; 96(11): 4376-86, 2009 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-19486662

RESUMO

Coefficients for active transport of ions and heat in vesicles with Ca(2+)-ATPase from sarcoplasmic reticulum are defined in terms of a newly proposed thermodynamic theory and calculated using experiments reported in the literature. The coefficients characterize in a quantitative manner different performances of the enzyme isoforms. Four enzyme isoforms are examined, namely from white and red muscle tissue, from blood platelets, and from brown adipose mitochondria. The results indicate that the isoforms have a somewhat specialized function. White muscle tissue and brown adipose tissue have the same active transport coefficient ratio, but the activity level of the enzyme in white muscle is higher than in brown adipose tissue. The thermogenesis ratio is high in both white muscle and brown adipose tissue, in agreement with a specific role in nonshivering thermogenesis. Other isoforms do not have this ability to generate heat. A calcium-dependence of the coefficients is found, which can be understood as being in accordance with the role of this ion as a messenger in muscle contraction as well as in thermogenesis. The investigation points to new experiments related to structure as well as to function of the isoforms.


Assuntos
Transporte Biológico Ativo , Isoenzimas/química , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/química , Termogênese , Tecido Adiposo Marrom/química , Tecido Adiposo Marrom/enzimologia , Algoritmos , Animais , Plaquetas/química , Plaquetas/enzimologia , Cálcio/química , Membrana Celular/química , Membrana Celular/enzimologia , Di-Hidrotaquisterol/química , Temperatura Alta , Humanos , Mitocôndrias/química , Mitocôndrias/enzimologia , Fibras Musculares de Contração Rápida/química , Fibras Musculares de Contração Rápida/enzimologia , Fibras Musculares de Contração Lenta/química , Fibras Musculares de Contração Lenta/enzimologia , Coelhos , Ratos , Termodinâmica , Vesículas Transportadoras/química , Vesículas Transportadoras/enzimologia
11.
Neuroscience ; 152(2): 371-80, 2008 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-18280666

RESUMO

ATP-sensitive potassium (K(ATP)) channels play an important role in controlling insulin secretion and vascular tone as well as protecting neurons under metabolic stress. We have previously demonstrated that stimulation of the K(ATP) channel by nitric oxide (NO) requires activation of Ras- and extracellular signal-regulated kinase (ERK) of the mitogen-activated protein kinase (MAPK) family. However, the mechanistic link between ERK and the K(atp) channel remained unknown. To investigate how ERK modulates the function of K(ATP) channels, we performed single-channel recordings in combination with site-directed mutagenesis. The Kir6.2/SUR1 channel, a neuronal K(ATP) channel isoform, was expressed in human embryonic kidney (HEK) 293 cells by transient transfection. Direct application of the activated ERK2 to the cytoplasmic surface of excised, inside-out patches markedly enhanced the single-channel activity of Kir6.2/SUR1 channels. The normalized open probability (NPo) and opening frequency were significantly increased, whereas the mean closed duration was reduced. The single-channel conductance level was not affected. The ERK2-induced stimulation of Kir6.2/SUR1 channels was prevented by heat-inactivation of the enzyme. Furthermore, alanine substitutions of T341 and S385 to disrupt the potential ERK phosphorylation sites present in the Kir6.2 subunit significantly abrogated the stimulatory effects of ERK2, while aspartate substitutions of T341 and S385 to mimic the (negative) charge effect of phosphorylation rendered a small yet significant reduction in the ATP sensitivity of the channel. Taken together, here we report for the first time that ERK2/MAPK activates neuronal-type K(ATP) channels, and this stimulation requires ERK phosphorylation of the Kir6.2 subunit at T341 and S385 residues. The ERK2-induced K(ATP) channel stimulation can be accounted for by changes in channel gating that destabilize the closed states and by reduction in the ATP sensitivity. As Kir6.2 is the pore-forming subunit of K(ATP) channels, ERK2-mediated phosphorylation may represent a common mechanism for K(ATP) channel regulation in different tissues.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Ativação do Canal Iônico/fisiologia , Canais de Potássio Corretores do Fluxo de Internalização/fisiologia , Trifosfato de Adenosina/farmacologia , Análise de Variância , Ácido Aspártico/metabolismo , Linhagem Celular Transformada , Di-Hidrotaquisterol/farmacologia , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/farmacologia , Proteínas de Fluorescência Verde/biossíntese , Temperatura Alta , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Potenciais da Membrana/efeitos da radiação , Mutagênese Sítio-Dirigida/métodos , Técnicas de Patch-Clamp/métodos , Fosforilação , Transfecção/métodos
12.
Lab Invest ; 87(6): 540-7, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17401435

RESUMO

An essential coagulation factor, tissue factor (TF), is rapidly expressed by human monocytes when exposed to a variety of agonists, such as lipopolysaccharide or tumor necrosis factor (TNF). We previously found that 1alpha,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) and its potent synthetic analogs downregulate TF and upregulate thrombomodulin expression on monocytic cells, counteracting the effects of TNF at the level of transcription. The human TF gene has characteristic binding sequences for activator protein-1 (AP-1) (c-Jun/c-Fos), nuclear factor-kappaB (NF-kappaB), Sp-1, and early growth response factor-1 (Egr-1). In this study, we investigated the regulatory mechanisms by which 1,25(OH)(2)D(3) inhibits TNF-induced TF expression in human monocytic cells. 1,25(OH)(2)D(3) reduced basal and TNF-induced TF activities. Gel-shift assay and luciferase assay with the respective reporter vectors showed that 1,25(OH)(2)D(3) reduced basal and TNF-induced activities of the nuclear proteins AP-1 and NF-kappaB, but not Egr-1. 1,25(OH)(2)D(3) inhibited TNF-induced phosphorylation of c-Jun without affecting phosphorylation of the other pathways. On the other hand, 1,25(OH)(2)D(3) directly inhibited nuclear binding and activities of NF-kappaB in the nucleus without affecting phosphorylation of the NF-kappaB activation pathway. These results indicate that 1,25(OH)(2)D(3) suppresses basal and TNF-induced TF expression in monocytic cells by inhibition of AP-1 and NF-kappaB activation pathways, but not of Egr-1. Our results may help to elucidate the regulatory mechanisms of 1,25(OH)(2)D(3) in TF induction, and may have physiological significance in the clinical challenge to use potential 1,25(OH)(2)D(3) analogs in antithrombotic therapy as well as immunomodulation and antineoplastic therapy of leukemia.


Assuntos
Di-Hidrotaquisterol/análogos & derivados , Monócitos/metabolismo , NF-kappa B/antagonistas & inibidores , Tromboplastina/antagonistas & inibidores , Fator de Transcrição AP-1/antagonistas & inibidores , Fator de Necrose Tumoral alfa/farmacologia , Células Cultivadas , Di-Hidrotaquisterol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Monócitos/efeitos dos fármacos , Tromboplastina/genética
13.
Perit Dial Int ; 25(4): 362-6, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16022093

RESUMO

BACKGROUND: Peritoneal dialysis (PD) patients are at risk for 25(OH) vitamin D deficiency due to effluent loss in addition to traditional risk factors. OBJECTIVES: To measure 25(OH) vitamin D deficiency in prevalent PD patients, to evaluate a replacement dose, and to determine the effects of correction. METHODS: 25(OH) vitamin D levels were drawn on prevalent PD patients. Patients deficientin 25(OH) vitamin D were given ergocalciferol, 50000 IU orally once per week for 4 weeks. Patients scored muscle weakness, bone pain, and fatigue on a scale of 0 (none) to 5 (severe). Serum calcium, phosphate, parathyroid hormone (PTH), and 25(OH) vitamin D, and 1,25(OH)2 vitamin D levels were obtained before and after treatment. RESULTS: 25(OH) vitamin D levels were measured in 29 PD patients. Deficiency (<15 ng/mL) was found in 28/29 (97%); 25/29 (86%) had undetectable levels (<7 ng/mL). One course of ergocalciferol corrected the deficiency in all but 1 patient, who required a second course. Scores for muscle weakness and bone pain fell from pre- to posttreatment (p < 0.001). 1,25(OH)2 vitamin D levels rose post ergocalciferol (from 20 to 26 pg/mL, n = 20, p = 0.09). Serum calcium, phosphate, and PTH levels did not change with ergocalciferol. CONCLUSIONS: Most PD patients had marked 25(OH) vitamin D deficiency, which was readily and safely corrected with one course of 50000 IU ergocalciferol, having no effect on serum calcium, phosphorus, or PTH, but complaints of muscle weakness and bone pain decreased. A prospective, placebo-controlled double-blinded study is needed to determine whether replacement of 25(PH) vitamin D is beneficial in PD patients.


Assuntos
Ergocalciferóis/uso terapêutico , Diálise Peritoneal/efeitos adversos , Deficiência de Vitamina D , Vitamina D/análogos & derivados , Administração Oral , Adulto , Idoso , Di-Hidrotaquisterol/análogos & derivados , Di-Hidrotaquisterol/sangue , Ergocalciferóis/administração & dosagem , Feminino , Seguimentos , Humanos , Falência Renal Crônica/sangue , Falência Renal Crônica/terapia , Masculino , Pessoa de Meia-Idade , Prevalência , Radioimunoensaio , Estudos Retrospectivos , Resultado do Tratamento , Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/etiologia
14.
Exp Clin Endocrinol Diabetes ; 113(7): 376-80, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16025398

RESUMO

BACKGROUND: The half synthetic Vitamin D analogue dihydrotachysterol (DHT) is widely used for hypocalcaemic hypoparathyroidism following surgical removal of parathyroids. Such treatment generally initiated by surgeons right after surgery has to be continued in clinical practice. Unfortunately, the required careful monitoring of calcium metabolism is often lacking and as demonstrated may lead to life-threatening conditions. PATIENTS AND METHODS: Here we report on five patients referred to our nephrology unit because of unknown impairment of renal function during therapy with DHT. All patients had clinical signs of hypercalcaemia. Since most symptoms are nonspecific they were not perceived by primary care physicians. In fact DHT treatment was continued for 4 - 50 years. In all cases calcium levels were determined after inadequate long intervals ranging from 3.08 to 4.97 mmol/l. Creatinine levels ranged from 277 to 365 micromol/l. All patients suffered from symptoms of severe hypercalcaemia, three of them needing intensive care unit treatment. RESULTS: All patients were treated effectively with a regimen consisting of intravenous saline, a loop diuretic, and application of bisphosphonates. As confirmed by renal biopsy persisting alleviation of renal function was due to calcifications. After discontinuation of DHT therapy patients were safely switched to shorter acting vitamin D derivates maintaining a normal calcium level. CONCLUSIONS: In comparison to short acting vitamin-D derivates hypercalcaemic episodes with DHT appear to last longer and may therefore occur with higher incidence. A future option could be the use of synthetic parathyroid hormone (s-PTH) recently shown to be safe and effective. Nevertheless a customized therapy and careful monitoring is indispensable in any case to prevent irreversible organ damage.


Assuntos
Di-Hidrotaquisterol/efeitos adversos , Di-Hidrotaquisterol/uso terapêutico , Hipoparatireoidismo/tratamento farmacológico , Insuficiência Renal/induzido quimicamente , Vitamina D/análogos & derivados , Idoso , Monitoramento de Medicamentos , Feminino , Humanos , Hipercalcemia/induzido quimicamente , Hipercalcemia/terapia , Masculino , Insuficiência Renal/terapia , Vitamina D/efeitos adversos , Vitamina D/uso terapêutico
16.
J Neurosci Res ; 80(4): 549-61, 2005 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-15825190

RESUMO

The mechanisms by which polyglutamine expansion causes common features of neuronal death remain unclear. Here we describe an approach for delivering polyglutamine expansions directly into cultured sympathetic neurons. Glutamine (Q) residues (n = 10, 22, 30) were conjugated with a peptide possessing translocation properties across plasma membranes (PDP) and a nuclear localization signal (NLS). These peptides were rapidly incorporated into sympathetic neurons and showed neurotoxicity in a length- and dose-dependent manner. A robust induction of c-jun and cyclin D1 occurred following treatment with PDP-Q22-NLS. Enhanced c-Jun phosphorylation showed c-Jun N-terminal kinase (JNK) activation. Coincidentally, TrkA tyrosine phosphorylation was decreased in association with loss of phospho-Akt, the downstream target of PI-3 kinase. Despite such proapoptotic signals, neither release of cytochrome c from mitochondria nor caspase-3/7 activation was detected. TdT-mediated dUTP nick-end labeling-positive nuclear condensation, but no fragmentation, occurred. At 24 hr of treatment, cytoplasmic Ca2+ levels began to become elevated, and the cellular level of ATP was decreased. Cytoplasmic Ca2+ responses to KCl depolarization displayed a delayed recovery, providing evidence for lack of Ca2+ homeostasis. The neurons became committed to death at about 36 hr when mitochondrial Ca2+ uptake declined concurrently with loss of mitochondrial membrane potential. Collectively, these results show that, despite induction of early apoptotic signals, nonapoptotic neuronal cell death occurred via perturbed Ca2+ homeostasis and suggest that mitochondrial permeability transition may play important roles in this model of neuronal death.


Assuntos
Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Modelos Biológicos , Neurônios/efeitos dos fármacos , Peptídeos/toxicidade , Clorometilcetonas de Aminoácidos/farmacologia , Animais , Animais Recém-Nascidos , Western Blotting/métodos , Carbonil Cianeto m-Clorofenil Hidrazona/farmacologia , Caspase 3 , Caspase 7 , Caspases/metabolismo , Contagem de Células/métodos , Células Cultivadas , Colforsina/farmacologia , Ciclina D1/genética , Ciclina D1/metabolismo , Cicloeximida/farmacologia , Di-Hidrotaquisterol/metabolismo , Relação Dose-Resposta a Droga , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Homeostase/efeitos dos fármacos , Imuno-Histoquímica/métodos , Marcação In Situ das Extremidades Cortadas/métodos , Ionóforos/farmacologia , Ácido Láctico/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Necrose/induzido quimicamente , Necrose/metabolismo , Fator de Crescimento Neural/farmacologia , Neurônios/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/farmacologia , Permeabilidade/efeitos dos fármacos , Inibidores da Síntese de Proteínas/farmacologia , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , RNA Mensageiro/metabolismo , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Estaurosporina/farmacologia , Gânglio Cervical Superior/citologia , Fatores de Tempo
17.
Brain Res Mol Brain Res ; 133(2): 215-23, 2005 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-15710238

RESUMO

3-nitropropionic acid (3-NPA), a complex II inhibitor of the electron transport chain, causes Huntington disease-like symptoms after administration into animals. However, primary mechanisms of cell death are not clearly understood. This study tested the hypothesis that 3-NPA leads to the generation of reactive oxygen species (ROS), mitochondrial DNA damage, and loss of mitochondrial function. Amplex red and horseradish peroxidase were used to accurately measure the amount of H2O2, and showed that PC12 cells treated with 3-NPA (4 mM) lead to the production of hydrogen peroxide (1 nmol/10(6) cells/h). This amount of 3-NPA also leads to a rapid decline of ATP levels. There was time- and dose-dependent mitochondrial DNA damage following 3-NPA treatment. Overexpression of the proto-oncogene bcl-2 protects cells from apoptosis induced by various stimuli. Overexpression of Bcl-2 leads to almost threefold higher levels of ATP and also decreased the 3-NPA-mediated induction of hydrogen peroxide by over 50%. Bcl-2-overexpressing PC12 cells were also protected from mitochondrial DNA damage. These data show that ROS production followed by mitochondrial DNA damage is the primary event in 3-NPA toxicity, and Bcl-2 protects PC12 cells from 3-NPA toxicity by preventing mitochondrial DNA damage.


Assuntos
Dano ao DNA/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Propionatos/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Contagem de Células/métodos , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Convulsivantes/farmacologia , DNA Mitocondrial/efeitos dos fármacos , DNA Mitocondrial/metabolismo , Di-Hidrotaquisterol/metabolismo , Relação Dose-Resposta a Droga , Citometria de Fluxo/métodos , Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Nitrocompostos , Células PC12 , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , RNA Mensageiro/metabolismo , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Tempo
18.
Exp Clin Endocrinol Diabetes ; 112(8): 444-50, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15372365

RESUMO

This observational study analyzes Ca-P metabolism and its impact on bone mass accrual and density and the muscle-bone mass/mass relationships in male and female children and adolescents who were parathyroidectomized because of thyroid carcinoma. Two hundred and eight children and adolescents (119 girls and 89 boys) from Gomel city (Belarus) and its rural surroundings were referred to our institution after having undergone total thyroidectomy for the treatment of advanced papillary thyroid cancer. A subgroup of children with demonstrated primary hypoparathyroidism received dihydrotachysterol (AT-10) and/or Ca supplementation. Among routine procedures over a maximum follow-up period of 5 years (average 3.7 years, maximum 8 visits), whole-body scans were taken using dual energy X-ray absorptiometry (DXA) at each visit in order to determine whole-body bone mineral content (TBMC), projected "areal" bone mineral density (TBMD), total lean mass (TLM) and total fat mass (TFM). The average serum Ca, P and AP concentrations over the whole observation period were significantly different between the groups; however, TBMC z-scores for all studied children were statistically similar in all visits. In girls, no between-group differences in height- and weight-controlled TBMC and TBMD or the TBMC/TLM ratio were observed (ANCOVA) and supplementation exerted no effect on these data, suggesting that the total bone mass accrual was not impaired by PTH deficiency in the studied conditions. However, non-supplemented boys showed lower values of the TBMC/TLM ratio than girls, and supplementation normalized these values in direct correlation with the induced improvement in serum P availability to bone. Results indicate that the primary impairment in parathyroid function and bone metabolism indicators in the thyroidectomized children was unrelated to any measurable change in crude bone mass values. However, in boys this condition impaired the TBMC/TLM ratio in such a way that the administered supplementation could normalize it as a function of improved P availability. Girls' skeleton seemed to have been naturally protected against the negative metabolic effect of the studied condition. An estrogen-induced enhancement of the biomechanical impact of muscle contractions on bone mass and structure could not be excluded in this group.


Assuntos
Densidade Óssea , Cálcio/uso terapêutico , Di-Hidrotaquisterol/uso terapêutico , Hipoparatireoidismo/tratamento farmacológico , Tireoidectomia/métodos , Absorciometria de Fóton , Adolescente , Fosfatase Alcalina/sangue , Composição Corporal , Cálcio/sangue , Carcinoma Papilar/cirurgia , Criança , Feminino , Seguimentos , Humanos , Hipoparatireoidismo/etiologia , Masculino , Hormônio Paratireóideo/sangue , Fosfatos/sangue , República de Belarus , Fatores Sexuais , Neoplasias da Glândula Tireoide/cirurgia
20.
Nephron Physiol ; 94(4): p62-73, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12972708

RESUMO

BACKGROUND: New 'non-calcaemic' analogues of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are entering the clinical arena and some of them have been shown to have differential effects in bone. This may have a bearing on the evolution of bone lesions in uraemic patients receiving vitamin D therapies. A potential mechanism for differential effects of analogues lies in their target cell inactivation. METHODS: Using a human osteoblastic cell line, MG-63, three analogues, 22-oxacalcitriol (OCT), 19-nor-1,25-dihydroxyvitamin D2 (paricalcitol) and 1alpha,25-dihydroxydihydrotachysterol2(1,25(OH)2DHT2), were compared with 1,25(OH)2D3 for (1) their affinity for the vitamin D receptor (VDR) by competitive displacement of tritiated 1,25(OH)2D3 from calf thymus VDR; (2) effects on 24-hydroxylase mRNA expression using comparative RT-PCR, and (3) rates of metabolism, using high performance liquid chromatography, over a 24-hour time course. RESULTS: Relative VDR-binding affinities (IC50) were 1,25(OH)2D3 (100%), OCT (25%), paricalcitol (14%) and 1,25(OH)2DHT2 (0.3%). A > or =3-fold increase in 24-hydroxylase mRNA expression was observed for all compounds at 2 h peaking at 7- to 8-fold above control levels by 12 h, with no significant difference between the analogues and 1,25(OH)2D3. Differences in their rates of metabolism were observed [calculated t(1/2) values = OCT (1.2 h) > paricalcitol (2.3 h) > 1,25(OH)2D3 (2.6 h) > 1,25(OH)2DHT2 (3.4 h)], with OCT having a significantly shorter half-life. CONCLUSION: In MG-63 cells these analogues up-regulate 24-hydroxylase mRNA expression with similar potency, in each case accelerating ligand inactivation, despite significant differences in VDR affinity. VDR affinity did not correspond to either 24-hydroxylase mRNA expression or the rates of ligand disappearance, suggesting cellular metabolism is one of several factors that determine the analogue specificity of these agents in bone.


Assuntos
Calcitriol/análogos & derivados , Calcitriol/farmacologia , Sistema Enzimático do Citocromo P-450/biossíntese , Osteoblastos/efeitos dos fármacos , Osteoblastos/enzimologia , Esteroide Hidroxilases/biossíntese , Animais , Calcitriol/metabolismo , Bovinos , Linhagem Celular , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Di-Hidrotaquisterol/química , Di-Hidrotaquisterol/metabolismo , Ergocalciferóis/metabolismo , Ergocalciferóis/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Hidroxilação/efeitos dos fármacos , Oxigenases de Função Mista/metabolismo , Osteoblastos/química , Ligação Proteica/efeitos dos fármacos , Receptores de Calcitriol/metabolismo , Esteroide Hidroxilases/genética , Esteroide Hidroxilases/metabolismo , Timo/química , Timo/enzimologia , Timo/metabolismo , Vitamina D3 24-Hidroxilase
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