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1.
Physiol Rep ; 9(16): e15008, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34405571

RESUMO

Medial artery calcification results from deposition of calcium hydroxyapatite crystals on elastin layers, and osteogenic changes in vascular smooth muscle cells. It is highly prevalent in patients with chronic kidney disease, diabetes, and peripheral artery disease (PAD), and when identified in lower extremity vessels, it is associated with increased amputation rates. This study aims to evaluate the effects of medial calcification on perfusion and functional recovery after hindlimb ischemia in rats. Medial artery calcification and acute limb ischemia were induced by vitamin D3 (VitD3 ) injection and femoral artery ligation in rats. VitD3 injection robustly induced calcification in the medial layer of femoral arteries in vivo. Laser Doppler perfusion imaging revealed that perfusion decreased and then partially recovered after hindlimb ischemia in vehicle-injected rats. In contrast, VitD3 -injected rats showed markedly impaired recovery of perfusion following limb ischemia. Accordingly, rats with medial calcification showed worse ischemia scores and delayed functional recovery compared with controls. Immunohistochemical and histological staining did not show differences in capillary density or muscle morphology between VitD3 - and vehicle-injected rats at 28 days after femoral artery ligation. The evaluation of cardiac and hemodynamic parameters showed that arterial stiffness was increased while cardiac function was preserved in VitD3 -injected rats. These findings suggest that medial calcification may contribute to impaired perfusion in PAD by altering vascular compliance, however, the specific mechanisms remain poorly understood. Reducing or slowing the progression of arterial calcification in patients with PAD may improve clinical outcomes.


Assuntos
Doença Arterial Periférica/fisiopatologia , Traumatismo por Reperfusão/fisiopatologia , Calcificação Vascular/fisiopatologia , Animais , Artérias/patologia , Colecalciferol/toxicidade , Membro Posterior/irrigação sanguínea , Masculino , Doença Arterial Periférica/complicações , Doença Arterial Periférica/etiologia , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/complicações , Calcificação Vascular/complicações , Calcificação Vascular/etiologia
2.
Food Chem ; 360: 129979, 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33984561

RESUMO

Vitamin D is a water-insoluble compound presented in two main forms (D2 and D3), susceptible to environmental conditions. Microencapsulation is an alternative to supplements and preserve vitamin D properties in foods. Entrapment efficiency (EE) is the main property to evaluate the encapsulation effectiveness and therefore it is of interest the study of analytical methods for the identification and quantification of this compound within the particle. This paper describes a low cost UV-Vis methodology validation to the identification and quantification of vitamin D3 in microparticles produced by hot homogenization. The method was validated following the International Conference on Harmonization (ICH) guidelines. To guarantee safe application in foodstuff, microparticles toxigenicity was evaluated with Allium cepa L. in vivo model, showing no cytotoxic nor genotoxic potential. High entrapment efficiency was obtained, the results also demonstrated that the concentration of vitamin D3 in microparticles can be safely accessed by the validated method.


Assuntos
Colecalciferol/análise , Colecalciferol/toxicidade , Suplementos Nutricionais/análise , Análise de Alimentos/métodos , Microesferas , Colecalciferol/química , Contaminação de Alimentos/análise , Cebolas/química
3.
Drug Chem Toxicol ; 44(6): 661-667, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31412708

RESUMO

Predictive toxicology plays an integral role in determining the toxicological profiles of chemicals for safety assessment. Vitamin D is an essential vitamin for the regulation of calcium absorption and homeostasis, as well as the treatment and prevention of several diseases such as rickets and osteomalacia. According to European Medicines Agency (EMA) Guideline on setting health-based exposure limits for use in risk identification in the manufacturing of different medicinal products in shared facilities, permitted daily exposure (PDE) calculation for active pharmaceutical ingredients (APIs) should be done by the medicinal product producers. PDE calculation is mainly based on critical toxicological endpoints such as repeated dose toxicity, genotoxicity, carcinogenicity, developmental and reproductive toxicity, and hypersensitivity potential. During this procedure, critical toxicological endpoints data of an API can be used to predict the PDE of another API that has a similar chemical structure. In the present paper, human toxicological endpoints of vitamin D2, D3, and their metabolites were evaluated and afterwards the data gaps in the toxicological endpoints were filled by forming a category. The read-across was justified by the structural and metabolic similarities. Molecular similarity and mechanistic relevance were found to be substantial, resulting in low uncertainty. The untested vitamin D analogs within the category can be read across with confidence to complete the data gaps related to the human health endpoints.


Assuntos
Colecalciferol , Ergocalciferóis , Colecalciferol/toxicidade , Humanos , Medição de Risco
4.
Mult Scler ; 25(9): 1326-1328, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30358476

RESUMO

Knowledge about complications of chronic ultra-high dose vitamin D supplementation is limited. We report a patient with primary progressive multiple sclerosis (MS) who presented with generalized weakness caused by hypercalcemia after uncontrolled intake of more than 50,000 IU of cholecalciferol per day over several months. Various treatment strategies were required to achieve normocalcemia. However, renal function improved only partly and further progression of MS was observed. We conclude that patients need to be informed about the risks of uncontrolled vitamin D intake and neurologists need to be alert of biochemical alterations and symptoms of vitamin D toxicity.


Assuntos
Colecalciferol/toxicidade , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Hipercalcemia/induzido quimicamente , Esclerose Múltipla Crônica Progressiva/tratamento farmacológico , Vitaminas/toxicidade , Colecalciferol/administração & dosagem , Humanos , Hipercalcemia/complicações , Masculino , Pessoa de Meia-Idade , Insuficiência Renal/etiologia , Vitaminas/administração & dosagem
5.
Vet Clin North Am Small Anim Pract ; 48(6): 1027-1038, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30173927

RESUMO

This article focuses on the 3 most commonly used rodenticide types: anticoagulants, bromethalin, and cholecalciferol. It is important to verify the active ingredient in any rodenticide exposure. Many owners use the term D-con to refer to any rodenticide regardless of the brand or type of rodenticide. The Environmental Protection Agency released their final ruling on rodenticide risk mitigation measures in 2008 and all products sold had to be compliant by June 2011, changing to consumer products containing either first-generation anticoagulants or nonanticoagulants, including bromethalin and cholecalciferol. These regulations have caused an increase in the number of bromethalin and cholecalciferol cases.


Assuntos
Anticoagulantes/toxicidade , Doenças do Gato , Doenças do Cão , Rodenticidas/toxicidade , Compostos de Anilina/toxicidade , Animais , Antídotos/uso terapêutico , Doenças do Gato/induzido quimicamente , Doenças do Gato/diagnóstico , Doenças do Gato/fisiopatologia , Doenças do Gato/terapia , Gatos , Colecalciferol/toxicidade , Doenças do Cão/induzido quimicamente , Doenças do Cão/diagnóstico , Doenças do Cão/fisiopatologia , Doenças do Cão/terapia , Cães , Vitamina K/uso terapêutico
6.
Can Vet J ; 57(12): 1284-1286, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27928177

RESUMO

The recommended daily allowance of vitamin D has been increased. Toxicosis in pets may increase as a result. A dog ingested ~ 200 000 IU of vitamin D, serum concentrations were above the reference range (RR) and decreased to the RR after lipid treatment. This is the first known report of lipid treatment for hypervitaminosis D.


Réduction des concentrations sériques de 25-hydroxyvitamine D à l'aide d'une émulsion intraveineuse de lipides chez un chien. L'apport quotidien recommandé de vitamine D a été accru. La toxicose chez les animaux de compagnie peut augmenter en raison de cette hausse. Un chien a ingéré ~ 200 000 UI de vitamine D, les concentrations sériques étaient supérieures à la fourchette de référence (FR) et a chuté à la FR après le traitement aux lipides. Il s'agit du premier rapport connu de traitement aux lipides pour la toxicose à l'hypervitaminose D.(Traduit par Isabelle Vallières).


Assuntos
Colecalciferol/toxicidade , Doenças do Cão/induzido quimicamente , Overdose de Drogas/veterinária , Emulsões Gordurosas Intravenosas/uso terapêutico , Vitamina D/análogos & derivados , Animais , Doenças do Cão/tratamento farmacológico , Cães , Overdose de Drogas/tratamento farmacológico , Masculino , Vitamina D/sangue
8.
Int J Pharm ; 487(1-2): 101-9, 2015 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-25835266

RESUMO

The natural selection of anticoagulant resistant rats has resulted in a need for an alternative to anticoagulant rodenticides which differs in both active ingredient and in the method of dosing. Cholecalciferol toxicity to rodents using the dermal route is demonstrated using a variety of penetration enhancing formulations in two in-vitro models and finally in-vivo. A 1 ml dose of 50/50 (v/v) DMSO/ethanol containing 15% (v/v) PEG 200 and 20% (w/v) cholecalciferol was judged as 'sufficiently effective' in line with the European Union's Biocidal Products Regulation (No. 528/2012) during in-vivo studies. This dose was found to cause 100% mortality in a rat population in 64.4h (± 22h).


Assuntos
Colecalciferol/administração & dosagem , Rodenticidas/administração & dosagem , Administração Cutânea , Animais , Comportamento Animal/efeitos dos fármacos , Celulose , Química Farmacêutica , Colecalciferol/química , Colecalciferol/toxicidade , Difusão , Dimetil Sulfóxido , Etanol , Europa (Continente) , Legislação de Medicamentos , Masculino , Polietilenoglicóis , Ratos , Ratos Sprague-Dawley , Rodenticidas/química , Rodenticidas/toxicidade , Absorção Cutânea , Solventes
9.
PLoS One ; 8(8): e70683, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23950982

RESUMO

The introduced Australian brushtail possum is a major vertebrate pest in New Zealand, with impacts on conservation and agriculture being managed largely through poisoning operations. Cholecalciferol (vitamin D3) is registered for use in controlling possums and despite its many advantages it is expensive and relatively inhumane. Combination of a high proportion of aspirin with a low proportion of cholecalciferol was effective in killing high proportions of groups of acclimatised, caged possums: this is attributed to both an unexpectedly high toxicity of the type of cholecalciferol used, and a proposed synergistic mechanism between the two compounds. Death was caused by localised damage to heart ventricles by aspirin, and inhibition of tissue repair by both aspirin and cholecalciferol. The observed toxicosis had lower impact on the welfare of possums than either compound administered alone, particularly aspirin alone. Residue analyses of bait remains in the GI tract suggested a low risk of secondary poisoning by either compound. The combination of cholecalciferol and aspirin has the potential to meet key requirements of cost-effectiveness and humaneness in controlling possum populations, but the effect of the combination in non-target species has yet to be tested.


Assuntos
Aspirina/toxicidade , Colecalciferol/toxicidade , Trato Gastrointestinal/efeitos dos fármacos , Controle de Pragas/métodos , Trichosurus/fisiologia , Animais , Aspirina/farmacocinética , Peso Corporal/efeitos dos fármacos , Colecalciferol/farmacocinética , Sinergismo Farmacológico , Feminino , Espécies Introduzidas , Dose Letal Mediana , Masculino , Nova Zelândia , Controle de Pragas/economia
10.
J Avian Med Surg ; 27(2): 136-47, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23971222

RESUMO

Over a 2-month period, individual birds belonging to species in multiple avian families, including Bucerotidae, Sturnidae, Columbidae, Corvidae, and Anatidae, were presented to the Animal Care Center at the Phoenix Zoo for emergency medical care. Common clinical findings were subdued behavior, weight loss, and an inability to fly. Biochemical abnormalities commonly included high calcium and uric acid concentrations and high to high-normal phosphorus concentrations. In cases in which necropsies were done, mineralization of organs often was present, frequently of the kidneys and cardiovascular system. Because of the high calcium and phosphorus concentrations, mineralization of tissues, cases representing multiple avian species, and the recent addition of rodent bait boxes containing cholecalciferol to the zoo's pest control program, a presumptive diagnosis of cholecalciferol toxicosis was made. Treatment most commonly consisted of daily fluid diuresis. These cases demonstrate that, although cholecalciferol is considered unlikely to cause relay toxicosis, primary toxicosis still should be considered in cases with sudden onset of nonspecific signs when exposure to cholecalciferol was possible.


Assuntos
Animais de Zoológico , Doenças das Aves/induzido quimicamente , Colecalciferol/toxicidade , Rodenticidas/envenenamento , Animais , Doenças das Aves/patologia , Aves , Feminino , Masculino , Rodenticidas/toxicidade
11.
Rev. lab. clín ; 5(1): 49-53, ene.-mar. 2012.
Artigo em Espanhol | IBECS | ID: ibc-99803

RESUMO

El objetivo de esta nota técnica es la descripción y comentarios de un caso clínico reciente de intoxicación por sobredosificación por vitamina D, y la correcta interpretación clínica y de los parámetros de laboratorio. Caso clínico. Lactante de 6 meses en tratamiento con Biominol® (suplemento vitamínico), ingresó debido a un estado de decaimiento e irritabilidad. Las analíticas iniciales muestran concentraciones de calcio iónico en sangre de 2,11mmol/L (intervalo de referencia (IR): 1,15-1,29mmol/L), y concentración de calcio total plasmático de 5,5mmol/L (IR: 2,25-2,75mmol/L). En nuestro laboratorio, las vitaminas D2 y D3 fueron determinadas por cromatografía líquida de alta resolución (HPLC), y por un método electroquimioluminiscente, que mide la vitamina D total. Los valores de vitamina D2 fueron 419ng/mL y vitamina D total 482ng/mL (IR: 30-100ng/mL). La intoxicación de vitamina D tuvo origen exógeno, debido al incremento de vitamina D2. El diagnóstico definitivo fue hipercalcemia severa secundaria a intoxicación por vitamina D y nefrocalcinosis secundaria a esta con función renal normal con hipercalciuria. Como conclusión, cabe destacar la importancia de la correcta dosificación de los pacientes y la determinación de las diferentes formas de vitamina D para averiguar su origen, realizando una correcta interpretación (AU)


The objective of this technical note describes and comments on a recent clinical case of poisoning by overdose of vitamin D, and the correct interpretation of clinical and laboratory parameters. Vitamin D is a fat-soluble vitamin involved in the absorption of calcium and phosphorus in the intestine. Administration of high doses for prolonged periods can cause hypercalcemia, leading to kidney failure and renal calcifications. Clinical case. The definitive diagnosis of this patient was severe hypercalcemia secondary to exogenous vitamin D poisoning, and nephrocalcinosis secondary to this with normal renal function with hypercalciuria. In conclusion, the correct dosing of patients and determination of different forms of vitamin D to trace its origin and making a correct interpretation is important. Male, 6 months old in treatment with Biominol® (vitamin D supplement), was admitted to the emergency department because of a state of decline and irritability. The initial analytical results showed an ionized calcium concentration in blood of 2.11mmol/L (reference interval (RI): 1.15 - 1.29mmol/L), and plasma total calcium concentration of 5.5mmol/L (RI: 2.25-2.75mmol/L). In our laboratory, Vitamin D2 and D3 were determined by liquid chromatography high resolution (HPLC), and an electrochemiluminescence method. The results showed a vitamin D2 419ng/mL and total vitamin D 482ng/mL (RI: 30-100ng/mL). It was found that the vitamin D overdose was of exogenous origin, due to increased vitamin D2 (AU)


Assuntos
Humanos , Masculino , Lactente , Overdose de Drogas/complicações , Overdose de Drogas/terapia , Vitamina D/administração & dosagem , Vitamina D/efeitos adversos , Diurese/fisiologia , Cromatografia , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão , Peso-Estatura/fisiologia , Eletrocardiografia , Diurese , Ergocalciferóis/toxicidade , Colecalciferol/toxicidade
12.
J Pharm Biomed Anal ; 55(1): 64-70, 2011 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-21300513

RESUMO

A reliable, accurate and reproducible method to quantify vitamin D3 (Vit. D3) in oily dietary supplements was developed after three Vit. D3 intoxications were diagnosed as reasonably resulting from a dietary administration of a cod liver oil based supplement. Liquid chromatography coupled to mass spectrometry operating in atmospheric pressure chemical ionization conditions (LC-APCI) and by using a deuterium labelled internal standard resulted to be an effective technique to reach the analytical aim. Due to the complexity of the oily matrix, the new analytical approach required a solid phase extraction step prior to analysis. The amount of Vit. D3 declared on the label of the cod liver oil based supplement for each soft capsule is 1.5µg. Consequently, the method was developed to quantify Vit. D3 amounts in the range 1-5µg/mL. To improve reliability of obtained data, both MS and MS/MS acquisition methods were employed. The method was evaluated by measuring the characteristic parameters such as linearity, precision, accuracy and robustness and cross checked against a certified pharmaceutical preparation. The LC-APCI-MS and MS/MS methods were applied in order to assess the Vit. D3 content in the dietary supplements taken by the intoxicated patients, found about three order of magnitude higher than that declared. The Vit. D3 content of other batches of the same commercial product was found as declared.


Assuntos
Colecalciferol/análise , Óleo de Fígado de Bacalhau/química , Suplementos Nutricionais/análise , Inspeção de Alimentos/métodos , Colecalciferol/química , Colecalciferol/toxicidade , Cromatografia Líquida de Alta Pressão , Suplementos Nutricionais/toxicidade , Rotulagem de Alimentos , Inocuidade dos Alimentos , Humanos , Espectrometria de Massas/métodos , Distúrbios Nutricionais/induzido quimicamente , Distúrbios Nutricionais/etiologia , Reprodutibilidade dos Testes , Extração em Fase Sólida
13.
J Korean Med Sci ; 25(9): 1305-12, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20808673

RESUMO

Thiazide is known to decrease urinary calcium excretion. We hypothesized that thiazide shows different hypocalciuric effects depending on the stimuli causing hypercalciuria. The hypocalciuric effect of hydrochlorothiazide (HCTZ) and the expression of transient receptor potential vanilloid 5 (TRPV5), calbindin-D(28K), and several sodium transporters were assessed in hypercalciuric rats induced by high calcium diet and vitamin D(3). Urine calcium excretion and the expression of transporters were measured from 4 groups of Sprague-Dawley rats; control, HCTZ, high calcium-vitamin D, and high calcium-vitamin D with HCTZ groups. HCTZ decreased urinary calcium excretion by 51.4% in the HCTZ group and only 15% in the high calcium-vitamin D with HCTZ group. TRPV5 protein abundance was not changed by HCTZ in the high calcium-vitamin D with HCTZ group compared to the high calcium-vitamin D group. Protein abundance of NHE3, SGLT1, and NKCC2 decreased in the hypercalciuric rats, and only SGLT1 protein abundance was increased by HCTZ in the hypercalciuric rats. The hypocalciuric effect of HCTZ is attenuated in high calcium and vitamin D-induced hypercalciuric rats. This attenuation seems to have resulted from the lack of HCTZ's effect on protein abundance of TRPV5 in severe hypercalciuric condition induced by high calcium and vitamin D.


Assuntos
Colecalciferol/toxicidade , Hidroclorotiazida/uso terapêutico , Hipercalciúria/tratamento farmacológico , Inibidores de Simportadores de Cloreto de Sódio/uso terapêutico , Animais , Cálcio/uso terapêutico , Cálcio/urina , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Hipercalciúria/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Transportador 1 de Glucose-Sódio/genética , Transportador 1 de Glucose-Sódio/metabolismo , Trocador 3 de Sódio-Hidrogênio , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo , Simportadores de Cloreto de Sódio-Potássio/genética , Simportadores de Cloreto de Sódio-Potássio/metabolismo , Membro 1 da Família 12 de Carreador de Soluto , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/metabolismo
14.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-177038

RESUMO

Thiazide is known to decrease urinary calcium excretion. We hypothesized that thiazide shows different hypocalciuric effects depending on the stimuli causing hypercalciuria. The hypocalciuric effect of hydrochlorothiazide (HCTZ) and the expression of transient receptor potential vanilloid 5 (TRPV5), calbindin-D(28K), and several sodium transporters were assessed in hypercalciuric rats induced by high calcium diet and vitamin D3. Urine calcium excretion and the expression of transporters were measured from 4 groups of Sprague-Dawley rats; control, HCTZ, high calcium-vitamin D, and high calcium-vitamin D with HCTZ groups. HCTZ decreased urinary calcium excretion by 51.4% in the HCTZ group and only 15% in the high calcium-vitamin D with HCTZ group. TRPV5 protein abundance was not changed by HCTZ in the high calcium-vitamin D with HCTZ group compared to the high calcium-vitamin D group. Protein abundance of NHE3, SGLT1, and NKCC2 decreased in the hypercalciuric rats, and only SGLT1 protein abundance was increased by HCTZ in the hypercalciuric rats. The hypocalciuric effect of HCTZ is attenuated in high calcium and vitamin D-induced hypercalciuric rats. This attenuation seems to have resulted from the lack of HCTZ's effect on protein abundance of TRPV5 in severe hypercalciuric condition induced by high calcium and vitamin D.


Assuntos
Animais , Ratos , Cálcio/uso terapêutico , Canais de Cálcio/genética , Colecalciferol/toxicidade , Hidroclorotiazida/uso terapêutico , Hipercalciúria/induzido quimicamente , Ratos Sprague-Dawley , Inibidores de Simportadores de Cloreto de Sódio/uso terapêutico , Transportador 1 de Glucose-Sódio/genética , Trocadores de Sódio-Hidrogênio/genética , Simportadores de Cloreto de Sódio-Potássio/genética , Canais de Cátion TRPV/genética
15.
Pest Manag Sci ; 64(2): 197-202, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17912688

RESUMO

BACKGROUND: Overcoming bait and poison shyness is critical to the success of pest control operations against rats and other rodents. The authors hypothesized that the N-methyl-D-aspartate receptor blocker, dextromethorphan, could prevent the acquired memory of sickness and sickness-induced anorexia resulting from rodents eating poisoned bait. RESULTS: Cholecalciferol (1/4 LD(50)) was mixed with dextromethorphan and fed to rats on two 2 day sessions, with an 18 day break in between. Dextromethorphan did not prevent poison shyness; during the second poisoning period, both the cholecalciferol only and the cholecalciferol plus dextromethorphan groups had lower intakes of the bait compared with the control and dextromethorphan only groups. In addition to the previously recorded symptoms of cholecalciferol poisoning, the rats in this trial were observed to have nose bleeds, weepy eyes, laboured breathing and, in the case of the cholecalciferol only treated group, a period of decreased water intake followed by a period of increased water intake. There was also a period of increased water intake in the cholecalciferol plus dextromethorphan group. CONCLUSION: Dextromethorphan failed to prevent poison shyness and the anorectic effect of cholecalciferol. However, it did reduce anorexia from 17 days in the cholecaliferol group to 8 days in the cholecalciferol plus dextromethorphan group.


Assuntos
Anorexia/tratamento farmacológico , Colecalciferol/toxicidade , Dextrometorfano/uso terapêutico , Comportamento Alimentar/efeitos dos fármacos , Venenos/toxicidade , Rodenticidas/toxicidade , Animais , Antagonistas de Aminoácidos Excitatórios/farmacologia , Masculino , Memória/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
16.
Anticancer Drugs ; 18(4): 447-57, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17351397

RESUMO

Analogs of 1,25-dihydroxyvitamin D3 with a reversed configuration at C-1 or C-24 and E or Z geometry of the double bond at C-22 in the side chain or at C-5 in the triene system were examined for their antiproliferative activity in vitro against a spectrum of various human cancer cell lines. The analogs coded PRI-2201 (calcipotriol), PRI-2202 and PRI-2205, such as calcitriol and tacalcitol (used as a referential agents), revealed antiproliferative activity against human HL-60, HL-60/MX2, MCF-7, T47D, SCC-25 and mouse WEHI-3 cancer cell lines. The toxicity studies in vivo showed that PRI-2202 and PRI-2205 are less toxic than referential agents. Even at total doses of 2.5-5.0 mg/kg distributed during 5 successive days, no changes in body weight were observed. Calcitriol and tacalcitol showed toxicity in the same protocol at 100 times lower doses. Calcipotriol was lethal to all mice after administration of a total dose of 5.0 mg/kg. The analog PRI-2205 appeared to be more active in mouse Levis lung cancer tumor growth inhibition than calcitriol, calcipotriol or PRI-2202. This analog did not reveal calcemic activity at doses which inhibit tumor growth in vivo nor at higher doses.


Assuntos
Antineoplásicos/farmacologia , Colecalciferol/análogos & derivados , Colecalciferol/farmacologia , Animais , Antineoplásicos/toxicidade , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Antígeno CD11b/metabolismo , Calcitriol/análogos & derivados , Calcitriol/farmacologia , Cálcio/sangue , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/patologia , Ciclo Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colecalciferol/toxicidade , Corantes , Feminino , Fibroblastos/metabolismo , Células HL-60 , Humanos , Receptores de Lipopolissacarídeos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Rodaminas , Estereoisomerismo , Sais de Tetrazólio , Tiazóis
17.
J Nutr ; 136(4): 1117-22, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16549491

RESUMO

The tolerable upper intake level (UL) for vitamin D is 50 mcg/d (2000 iu/d) in North America and in Europe. In the United Kingdom a guidance level exists for vitamin D, 25 mcg/d (1000 iu/d), defined as the dose "of vitamins and minerals that potentially susceptible individuals could take daily on a life-long basis, without medical supervision in reasonable safety." Exposure of skin to sunshine can safely provide an adult with vitamin D in an amount equivalent to an oral dose of 250 mcg/d. The incremental consumption of 1 mcg/d of vitamin D3 raises serum 25-hydroxyvitamin D [25(OH)D ] by approximately 1 nmol/L (0.4 microg/L). Published reports suggest toxicity may occur with 25(OH)D concentrations beyond 500 nmol/L (200 microg/L). Older adults are advised to maintain serum 25(OH)D concentrations >75 nmol/L. The preceding numbers indicate that vitamin D3 intake at the UL raises 25(OH)D by approximately 50 nmol/L and that this may be more desirable than harmful. The past decade has produced separate North American, European, and U.K. reports that address UL or guidance-level values for vitamin D. Despite similar well-defined models for risk assessment, each report has failed to adapt its message to new evidence of no adverse effects at higher doses. Inappropriately low UL values, or guidance values, for vitamin D have hindered objective clinical research on vitamin D nutrition, they have hindered our understanding of its role in disease prevention, and restricted the amount of vitamin D in multivitamins and foods to doses too low to benefit public health.


Assuntos
Política Nutricional , Necessidades Nutricionais , Vitamina D/administração & dosagem , Adulto , Animais , Calcifediol/sangue , Calcifediol/toxicidade , Colecalciferol/administração & dosagem , Colecalciferol/toxicidade , Suplementos Nutricionais , Alimentos Fortificados , Humanos , Hipercalcemia/induzido quimicamente , Luz Solar , Deficiência de Vitamina D/prevenção & controle
18.
Regul Pept ; 129(1-3): 125-32, 2005 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15927707

RESUMO

Adrenomedullin (ADM) has the vasodilatory properties and involves in the pathogenesis of vascular calcification. ADM could be degraded into more than six fragments in the body, including ADM(27-52), and we suppose the degrading fragments from ADM do the same bioactivities as derived peptides from pro-adrenomedullin. The present study carries forward by assessing the effects on vascular calcification of the systemic administration of ADM(27-52). The rat vascular calcific model was replicated with vitamin D3 and nicotine. ADM or/and ADM(27-52) were systemically administrated with mini-osmotic pump beginning at seventh day after the model replication for 25 days. Vascular calcific nodules histomorphometry, vascular calcium content, vascular calcium uptake, alkaline phosphatase activity, and osteopontin-mRNA quantification in aorta were assessed. ADM limited 40.2% vascular calcific nodules (P<0.01), did not effect on calcium content (P>0.05), reduced 44.4% calcium uptake (P<0.01), lowered 21.1% alkaline phosphatase activity (P<0.01), and regulated 40.9% downwards osteopontin-mRNA expression (P<0.01) in the aorta of rats with vascular calcification. ADM(27-52) receded 32.0% vascular calcific nodules (P<0.01), taken from 55.5% calcium content (P<0.01), did not affect calcium uptake (P>0.05), inhibited 22.5% alkaline phosphatase activity (P<0.01), and restrained 21.9% osteopontin-mRNA expression (P<0.01) in the aorta of rats with vascular calcification. Both of ADM and ADM(27-52) did interact on vascular calcification each other. ADM could partially antagonize the effects of ADM(27-52) in taking from calcium content (17.5%, P<0.01) and in receding vascular calcific nodules (18.6%, P<0.01). ADM could obviously enhance the action of ADM(27-52) in inhibiting alkaline phosphatase activity (14.4%, P<0.01) and in reducing calcium uptake (11.4%, P<0.01). ADM(27-52) could partially antagonize the effects of ADM on regulating downwards osteopontin-mRNA expression (17.0%, P<0.01). It is concluded that ADM(27-52) derived from ADM acts as an inhibitory agent on vascular calcification, with special mechanisms different from ADM derived from ADM progenitor molecule.


Assuntos
Aorta Torácica/metabolismo , Calcinose/tratamento farmacológico , Fragmentos de Peptídeos/administração & dosagem , Adrenomedulina , Animais , Aorta Torácica/patologia , Calcinose/induzido quimicamente , Calcinose/metabolismo , Colecalciferol/toxicidade , Masculino , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Fragmentos de Peptídeos/metabolismo , Ratos , Ratos Sprague-Dawley
19.
Regul Pept ; 129(1-3): 167-76, 2005 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15927713

RESUMO

Ghrelin is a new peptide with regulatory actions in growth hormone secretion in the anterior pituitary gland and in energy metabolism. Currently, ghrelin has potently protective effects in cardiovascular diseases. We used an in vivo model of rat vascular calcification induced by vitamin D3 and nicotine and one of cultured rat vascular smooth muscular cells (VSMCs) calcification induced by beta-glycerophosphate to study the possible mechanism in the regulatory action of ghrelin in vascular calcification. Calcification increased total Ca2+ content and 45Ca2+ deposition in aortas and VSMCs and alkaline phosphatase (ALP) activation in plasma, aortas and VSMCs. However, calcified aortas and VSMCs showed a significant decrease in osteopontin (OPN) mRNA expression and a marked reduction of ghrelin levels in plasma and its mRNA expression in aortas. The aortic calcification was significantly attenuated by subcutaneous administration of ghrelin 30 and 300 nmol kg(-1) day(-1) for 4 weeks, and the latter dosage was more potent than the former. Ghrelin treatment at the two dosages reduced the total aorta Ca2+ content by 24.4% and 28.1%, aortic 45Ca2+ deposition by 18.4% and 24.9%, plasma ALP activity by 36.6% and 76.7%, and aortic ALP activity by 10.3% and 47.6% (all P < 0.01 or 0.05), respectively. Ghrelin at 10(-8)-10(-6) mol/L attenuated the calcification in cultured VSMCs, with decreased total Ca2+ content, 45Ca2+ deposition and ALP activity and increased OPN mRNA expression, in a concentration-dependent manner. In addition, endothelin levels in plasma and aortas and its mRNA expression in aortas significantly increased with calcification, but ghrelin treatment significantly decreased endothelin levels and mRNA expression, with the high dosage being more potent than the lower dosage. These results indicate that local ghrelin in vascular was down-regulated during vascular calcification, whereas administration of ghrelin effectively attenuated vascular and VSMCs calcification.


Assuntos
Aorta/metabolismo , Calcinose/tratamento farmacológico , Músculo Liso Vascular/metabolismo , Hormônios Peptídicos/administração & dosagem , Animais , Aorta/patologia , Calcinose/induzido quimicamente , Calcinose/metabolismo , Células Cultivadas , Colecalciferol/toxicidade , Grelina , Masculino , Músculo Liso Vascular/patologia , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Ratos
20.
Atherosclerosis ; 183(1): 41-7, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15907853

RESUMO

The present study was designed to test the hypothesis that arterial baroreflex dysfunction promotes the development of atherosclerosis. Experiment 1: the baroreflex sensitivity (BRS) was measured in 30 Sprague-Dawley (SD) rats in conscious state with a computerized blood pressure monitoring system. Four weeks later, the rats were administered with Vitamin D3, and fed with the high-cholesterol diet for 8 weeks to induce atherosclerosis. The hearts and aortae were removed for pathological examination. A negative correlation was found between BRS and the scores of coronary (r=-0.464, P<0.01) or aortic atherosclerosis (r=-0.524, P<0.01) in SD rats. Experiment 2: sinoaortic denervation (SAD) was performed in SD rats. Then atherosclerosis was also induced. The atherosclerosis scores in SAD rats were significantly higher than those in sham-operated rats (aortic score: 1.50+/-0.41 versus 1.10+/-0.39, P<0.05; coronary score: 1.70+/-0.35 versus 1.25+/-0.54, P<0.05). Using immunohistochemistry and Western blotting methods, it was found that the expressions of C-reactive protein, intercellular adhesion molecule-1 and vascular-cell adhesion molecule-1 in coronary artery and aorta were increased in SAD rats compared with sham-operated rats. These results indicate that arterial baroreflex dysfunction promotes the development of atherosclerosis in rats, and that inflammation may be involved in this process.


Assuntos
Aorta/fisiopatologia , Aterosclerose/etiologia , Barorreflexo , Artérias Carótidas/fisiopatologia , Reflexo Anormal/fisiologia , Animais , Aorta/química , Aorta/inervação , Aorta/patologia , Doenças da Aorta/etiologia , Doenças da Aorta/fisiopatologia , Aterosclerose/fisiopatologia , Denervação Autônoma , Proteína C-Reativa/análise , Artérias Carótidas/inervação , Colecalciferol/toxicidade , Dieta Aterogênica , Hipercolesterolemia/complicações , Hipertensão/induzido quimicamente , Hipertensão/complicações , Molécula 1 de Adesão Intercelular/análise , Masculino , Miocárdio/química , Miocárdio/patologia , Fenilefrina/toxicidade , Ratos , Ratos Sprague-Dawley , Molécula 1 de Adesão de Célula Vascular/análise
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