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1.
Physiol Rep ; 9(16): e15008, 2021 08.
Article in English | MEDLINE | ID: mdl-34405571

ABSTRACT

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.


Subject(s)
Peripheral Arterial Disease/physiopathology , Reperfusion Injury/physiopathology , Vascular Calcification/physiopathology , Animals , Arteries/pathology , Cholecalciferol/toxicity , Hindlimb/blood supply , Male , Peripheral Arterial Disease/complications , Peripheral Arterial Disease/etiology , Rats , Rats, Sprague-Dawley , Reperfusion Injury/complications , Vascular Calcification/complications , Vascular Calcification/etiology
2.
Food Chem ; 360: 129979, 2021 Oct 30.
Article in English | MEDLINE | ID: mdl-33984561

ABSTRACT

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.


Subject(s)
Cholecalciferol/analysis , Cholecalciferol/toxicity , Dietary Supplements/analysis , Food Analysis/methods , Microspheres , Cholecalciferol/chemistry , Food Contamination/analysis , Onions/chemistry
3.
Drug Chem Toxicol ; 44(6): 661-667, 2021 Nov.
Article in English | MEDLINE | ID: mdl-31412708

ABSTRACT

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.


Subject(s)
Cholecalciferol , Ergocalciferols , Cholecalciferol/toxicity , Humans , Risk Assessment
4.
Mult Scler ; 25(9): 1326-1328, 2019 08.
Article in English | MEDLINE | ID: mdl-30358476

ABSTRACT

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.


Subject(s)
Cholecalciferol/toxicity , Drug-Related Side Effects and Adverse Reactions , Hypercalcemia/chemically induced , Multiple Sclerosis, Chronic Progressive/drug therapy , Vitamins/toxicity , Cholecalciferol/administration & dosage , Humans , Hypercalcemia/complications , Male , Middle Aged , Renal Insufficiency/etiology , Vitamins/administration & dosage
5.
Vet Clin North Am Small Anim Pract ; 48(6): 1027-1038, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30173927

ABSTRACT

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.


Subject(s)
Anticoagulants/toxicity , Cat Diseases , Dog Diseases , Rodenticides/toxicity , Aniline Compounds/toxicity , Animals , Antidotes/therapeutic use , Cat Diseases/chemically induced , Cat Diseases/diagnosis , Cat Diseases/physiopathology , Cat Diseases/therapy , Cats , Cholecalciferol/toxicity , Dog Diseases/chemically induced , Dog Diseases/diagnosis , Dog Diseases/physiopathology , Dog Diseases/therapy , Dogs , Vitamin K/therapeutic use
6.
Can Vet J ; 57(12): 1284-1286, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27928177

ABSTRACT

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).


Subject(s)
Cholecalciferol/toxicity , Dog Diseases/chemically induced , Drug Overdose/veterinary , Fat Emulsions, Intravenous/therapeutic use , Vitamin D/analogs & derivatives , Animals , Dog Diseases/drug therapy , Dogs , Drug Overdose/drug therapy , Male , Vitamin D/blood
8.
Int J Pharm ; 487(1-2): 101-9, 2015 Jun 20.
Article in English | MEDLINE | ID: mdl-25835266

ABSTRACT

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).


Subject(s)
Cholecalciferol/administration & dosage , Rodenticides/administration & dosage , Administration, Cutaneous , Animals , Behavior, Animal/drug effects , Cellulose , Chemistry, Pharmaceutical , Cholecalciferol/chemistry , Cholecalciferol/toxicity , Diffusion , Dimethyl Sulfoxide , Ethanol , Europe , Legislation, Drug , Male , Polyethylene Glycols , Rats , Rats, Sprague-Dawley , Rodenticides/chemistry , Rodenticides/toxicity , Skin Absorption , Solvents
9.
PLoS One ; 8(8): e70683, 2013.
Article in English | MEDLINE | ID: mdl-23950982

ABSTRACT

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.


Subject(s)
Aspirin/toxicity , Cholecalciferol/toxicity , Gastrointestinal Tract/drug effects , Pest Control/methods , Trichosurus/physiology , Animals , Aspirin/pharmacokinetics , Body Weight/drug effects , Cholecalciferol/pharmacokinetics , Drug Synergism , Female , Introduced Species , Lethal Dose 50 , Male , New Zealand , Pest Control/economics
10.
J Avian Med Surg ; 27(2): 136-47, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23971222

ABSTRACT

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.


Subject(s)
Animals, Zoo , Bird Diseases/chemically induced , Cholecalciferol/toxicity , Rodenticides/poisoning , Animals , Bird Diseases/pathology , Birds , Female , Male , Rodenticides/toxicity
11.
Rev. lab. clín ; 5(1): 49-53, ene.-mar. 2012.
Article in Spanish | IBECS | ID: ibc-99803

ABSTRACT

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)


Subject(s)
Humans , Male , Infant , Drug Overdose/complications , Drug Overdose/therapy , Vitamin D/administration & dosage , Vitamin D/adverse effects , Diuresis/physiology , Chromatography , Chromatography, High Pressure Liquid/instrumentation , Chromatography, High Pressure Liquid , Weight by Height/physiology , Electrocardiography , Diuresis , Ergocalciferols/toxicity , Cholecalciferol/toxicity
12.
J Pharm Biomed Anal ; 55(1): 64-70, 2011 Apr 28.
Article in English | MEDLINE | ID: mdl-21300513

ABSTRACT

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.


Subject(s)
Cholecalciferol/analysis , Cod Liver Oil/chemistry , Dietary Supplements/analysis , Food Inspection/methods , Cholecalciferol/chemistry , Cholecalciferol/toxicity , Chromatography, High Pressure Liquid , Dietary Supplements/toxicity , Food Labeling , Food Safety , Humans , Mass Spectrometry/methods , Nutrition Disorders/chemically induced , Nutrition Disorders/etiology , Reproducibility of Results , Solid Phase Extraction
13.
J Korean Med Sci ; 25(9): 1305-12, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20808673

ABSTRACT

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.


Subject(s)
Cholecalciferol/toxicity , Hydrochlorothiazide/therapeutic use , Hypercalciuria/drug therapy , Sodium Chloride Symporter Inhibitors/therapeutic use , Animals , Calcium/therapeutic use , Calcium/urine , Calcium Channels/genetics , Calcium Channels/metabolism , Hypercalciuria/chemically induced , Rats , Rats, Sprague-Dawley , Sodium-Glucose Transporter 1/genetics , Sodium-Glucose Transporter 1/metabolism , Sodium-Hydrogen Exchanger 3 , Sodium-Hydrogen Exchangers/genetics , Sodium-Hydrogen Exchangers/metabolism , Sodium-Potassium-Chloride Symporters/genetics , Sodium-Potassium-Chloride Symporters/metabolism , Solute Carrier Family 12, Member 1 , TRPV Cation Channels/genetics , TRPV Cation Channels/metabolism
14.
Article in English | WPRIM (Western Pacific) | ID: wpr-177038

ABSTRACT

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.


Subject(s)
Animals , Rats , Calcium/therapeutic use , Calcium Channels/genetics , Cholecalciferol/toxicity , Hydrochlorothiazide/therapeutic use , Hypercalciuria/chemically induced , Rats, Sprague-Dawley , Sodium Chloride Symporter Inhibitors/therapeutic use , Sodium-Glucose Transporter 1/genetics , Sodium-Hydrogen Exchangers/genetics , Sodium-Potassium-Chloride Symporters/genetics , TRPV Cation Channels/genetics
15.
Pest Manag Sci ; 64(2): 197-202, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17912688

ABSTRACT

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.


Subject(s)
Anorexia/drug therapy , Cholecalciferol/toxicity , Dextromethorphan/therapeutic use , Feeding Behavior/drug effects , Poisons/toxicity , Rodenticides/toxicity , Animals , Excitatory Amino Acid Antagonists/pharmacology , Male , Memory/drug effects , Rats , Rats, Sprague-Dawley
16.
Anticancer Drugs ; 18(4): 447-57, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17351397

ABSTRACT

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.


Subject(s)
Antineoplastic Agents/pharmacology , Cholecalciferol/analogs & derivatives , Cholecalciferol/pharmacology , Animals , Antineoplastic Agents/toxicity , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , CD11b Antigen/metabolism , Calcitriol/analogs & derivatives , Calcitriol/pharmacology , Calcium/blood , Carcinoma, Lewis Lung/drug therapy , Carcinoma, Lewis Lung/pathology , Cell Cycle/drug effects , Cell Differentiation/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cholecalciferol/toxicity , Coloring Agents , Female , Fibroblasts/metabolism , HL-60 Cells , Humans , Lipopolysaccharide Receptors/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/pathology , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Rhodamines , Stereoisomerism , Tetrazolium Salts , Thiazoles
17.
J Nutr ; 136(4): 1117-22, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16549491

ABSTRACT

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.


Subject(s)
Nutrition Policy , Nutritional Requirements , Vitamin D/administration & dosage , Adult , Animals , Calcifediol/blood , Calcifediol/toxicity , Cholecalciferol/administration & dosage , Cholecalciferol/toxicity , Dietary Supplements , Food, Fortified , Humans , Hypercalcemia/chemically induced , Sunlight , Vitamin D Deficiency/prevention & control
18.
Regul Pept ; 129(1-3): 125-32, 2005 Jul 15.
Article in English | MEDLINE | ID: mdl-15927707

ABSTRACT

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.


Subject(s)
Aorta, Thoracic/metabolism , Calcinosis/drug therapy , Peptide Fragments/administration & dosage , Adrenomedullin , Animals , Aorta, Thoracic/pathology , Calcinosis/chemically induced , Calcinosis/metabolism , Cholecalciferol/toxicity , Male , Nicotine/toxicity , Nicotinic Agonists/toxicity , Peptide Fragments/metabolism , Rats , Rats, Sprague-Dawley
19.
Regul Pept ; 129(1-3): 167-76, 2005 Jul 15.
Article in English | MEDLINE | ID: mdl-15927713

ABSTRACT

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.


Subject(s)
Aorta/metabolism , Calcinosis/drug therapy , Muscle, Smooth, Vascular/metabolism , Peptide Hormones/administration & dosage , Animals , Aorta/pathology , Calcinosis/chemically induced , Calcinosis/metabolism , Cells, Cultured , Cholecalciferol/toxicity , Ghrelin , Male , Muscle, Smooth, Vascular/pathology , Nicotine/toxicity , Nicotinic Agonists/toxicity , Rats
20.
Atherosclerosis ; 183(1): 41-7, 2005 Nov.
Article in English | MEDLINE | ID: mdl-15907853

ABSTRACT

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.


Subject(s)
Aorta/physiopathology , Atherosclerosis/etiology , Baroreflex , Carotid Arteries/physiopathology , Reflex, Abnormal/physiology , Animals , Aorta/chemistry , Aorta/innervation , Aorta/pathology , Aortic Diseases/etiology , Aortic Diseases/physiopathology , Atherosclerosis/physiopathology , Autonomic Denervation , C-Reactive Protein/analysis , Carotid Arteries/innervation , Cholecalciferol/toxicity , Diet, Atherogenic , Hypercholesterolemia/complications , Hypertension/chemically induced , Hypertension/complications , Intercellular Adhesion Molecule-1/analysis , Male , Myocardium/chemistry , Myocardium/pathology , Phenylephrine/toxicity , Rats , Rats, Sprague-Dawley , Vascular Cell Adhesion Molecule-1/analysis
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