RESUMO
In recent years, specially designed patches containing beta emitters have been developed for contact brachytherapy of skin lesions. The aim of the present work was to evaluate the biological effects of the (32)P-patch on the skin of Sencar mice as a result of a brachytherapy treatment. For this purpose, a (32)P-patch was prepared with Chromic (32)P-phosphate and silicone and the classical model of two-stage skin carcinogenesis was reproduced in Sencar mice. Animals were divided in six groups. Four groups received the contact brachytherapy treatments using a scheme of a single session of 40 and 60Gy (SD40 and SD60) and a scheme of two sessions of 40 and 60Gy each (FD40 and FD60). The other two groups were used as controls of the single (CSD) and the fractionated (CFD) treatments. Radiation doses were estimated with equations derived from the MIRD DOSE scheme, and biologically effective doses (BED) were calculated according to equations derived from the linear-quadratic model. The endpoint to evaluate the treatments effects was tumor size after a follow-up period of 44 days. Finally, animals were sacrificed in order to get samples of all tumors for histological analysis and PCNA staining. Erythema, dermatitis and skin ulceration developed in almost all treated animals, but they gradually healed with regeneration of tissue during the follow-up period. Radiation effects on the skin of SD40, SD60, FD40 and FD60 showed a significant reduction of the tumor size with regard to controls, independently of the scheme and the radiation dose considered. PCNA staining scores of control groups were higher than for treated groups, independently of the scheme and the radiation dose considered. This radioactive (32)P-silicone-patch which is easy to prepare and use in the treatment of skin diseases, seems promising as a radioactive device for clinical use.
Assuntos
Braquiterapia/métodos , Radioisótopos de Fósforo/uso terapêutico , Neoplasias Cutâneas/radioterapia , Pele/efeitos da radiação , Administração Cutânea , Animais , Feminino , Camundongos , Camundongos Endogâmicos SENCAR , Antígeno Nuclear de Célula em Proliferação/metabolismo , Dosagem Radioterapêutica , Neoplasias Cutâneas/metabolismoRESUMO
The purpose of the present work was to evaluate the iron bioavailability of a new ferric pyrophosphate salt stabilized and solubilized with glycine. The prophylactic-preventive test in rats, using ferrous sulfate as the reference standard, was applied as the evaluating methodology both using water and yogurt as vehicles. Fifty female Sprague-Dawley rats weaned were randomized into five different groups (group 1: FeSO(4); group 2: pyr; group 3: FeSO(4) + yogurt; group 4: pyr + yogurt and group 5: control). The iron bioavailability (BioFe) of each compound was calculated using the formula proposed by Dutra-de-Oliveira et al. where BioFe % = (HbFef - HbFei) x 100/ToFeIn. Finally, the iron bioavailability results of each iron source were also given as relative biological value (RBV) using ferrous sulfate as the reference standard. The results showed that both BioFe % and RBV % of the new iron source tested is similar to that of the reference standard independently of the vehicle employed for the fortification procedure (FeSO(4) 49.46 +/- 12.0% and 100%; Pyr 52.66 +/- 15.02% and 106%; FeSO(4) + yogurth 54.39 +/- 13.92% and 110%; Pyr + yogurt 61.97 +/- 13.54% and 125%; Control 25.30 +/- 6.60, p < 0.05). Therefore, the stabilized and soluble ferric pyrophosphate may be considered as an optimal iron source for food fortification.
Assuntos
Difosfatos/química , Alimentos Fortificados , Ferro da Dieta/farmacocinética , Ferro/química , Análise de Variância , Animais , Disponibilidade Biológica , Dieta , Difosfatos/farmacocinética , Feminino , Compostos Ferrosos/química , Compostos Ferrosos/farmacocinética , Ferro/farmacocinética , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Padrões de Referência , Solubilidade , Água , IogurteRESUMO
The purpose of this study was to design and evaluate a 32P patch for brachytherapy of skin diseases. We employed Phosphoric-32P-acid and Chromic 32P-phosphate in combination with natural rubber or silicone to produce the patches. Stability studies in vitro to evaluate the leakage of radioactivity, autoradiographic studies to evaluate homogeneity and shielding, as well as therapeutic efficacy in an animal model of skin cancer of the selected 32P patch were performed. The 32P-silicone-patch demonstrated its safety for external application. Tumor growth was arrest and complete regressions of tumors were seen in some other cases with 40 Gy applied in a single-dose scheme. In conclusion, the 32P-silicone-patch is easy to prepare and use in the treatment of skin diseases.
Assuntos
Braquiterapia/métodos , Radioisótopos de Fósforo/administração & dosagem , Neoplasias Cutâneas/radioterapia , Animais , Compostos de Cromo/administração & dosagem , Compostos de Cromo/química , Sistemas de Liberação de Medicamentos/métodos , Feminino , Histocitoquímica , Camundongos , Camundongos Endogâmicos SENCAR , Fosfatos/administração & dosagem , Fosfatos/química , Ácidos Fosfóricos/administração & dosagem , Ácidos Fosfóricos/química , Radioisótopos de Fósforo/química , Planejamento da Radioterapia Assistida por Computador , Distribuição Aleatória , Borracha/administração & dosagem , Borracha/química , Silicones/administração & dosagem , Silicones/químicaRESUMO
Keloids are the result of excessive fibroblast proliferation and then over-abundant collagen deposition. There is no method able to guarantee absolute success in the therapeutic approach to keloids. Our case report involves a female patient with six lesions treated with a 32P-patch brachyradiotherapy. Pre-treatment and adjuvant treatment of the lesions were performed with thiomucase, 5-fluoruracil, procaine and triamcinolone. Taking into account the activity contained in each of the patches and the total radiation dose to be administered according to clinical practice, dosimetric calculations were done for each lesion. Separate silicone patches with chromic [32P]phosphate were designed for each lesion based on these calculations. Total remission was achieved in three treated lesions. The other lesions did not achieve total remission yet, but their sizes are diminishing. The differences observed in treatment outcome may be related with lesion features, adjuvant treatments and/or treatment schedule.
Assuntos
Braquiterapia/métodos , Cicatriz Hipertrófica/radioterapia , Queloide/radioterapia , Radioisótopos de Fósforo/uso terapêutico , Idoso de 80 Anos ou mais , Cicatriz Hipertrófica/patologia , Feminino , Humanos , Queloide/patologia , Doses de Radiação , Pele/patologiaRESUMO
The aim of the present study was to assess dietary zinc effects on femur weight and mineral content in growing rats. For this purpose, 70 weanling Sprague-Dawley rats were divided into four groups. Each group was subject to a diet containing 2 (BZ), 5 (DZ), 10 (MZ), and 30 (CZ) ppm zinc. The calcium and magnesium content in all diets was 5 g/kg and 507 mg/kg, respectively. The animals were kept on this regime for 28 d and then sacrificed and their femurs were removed for analysis using atomic absorption spectrophotometry. The weights of the BZ and DZ groups were significantly different from the MZ and CZ groups (38.5+/-10.5, 89.9+/-13.7, 118.6+/-13.6, and 134+/-19.9 g, p<0.01) respectively. There were no differences between the MZ and CZ groups. Femur weight also varied with dietary zinc, as it was significantly different among all groups (BZ, 265+/-49 mg; DZ, 380+/-40 mg; MZ, 452+/-54 mg; CZ, 735+/-66 mg; p<0.01). The femur zinc content varied with diets, following a different pattern than the above parameters. Femur zinc from the BZ group (51.5+/-5.4 ppm) was significantly different from the MZ and CZ groups (115.9+/-14.2 and 175.0+/-13.5 ppm, respectively), whereas the DZ group (62.5+/-11.3 ppm) did not differ from the other three groups. The femur content of calcium (BZ, 83.2+/-9.8 mg/g; DZ, 88.0+/-9.2 mg/g; MZ, 90.2+/-13.6 mg/g; CZ, 83.1+/-14.7 mg/g) and magnesium (BZ, 1.82+/-0.13 mg/g; DZ, 1.98+/-0.09 mg/g; MZ, 1.93+/-14 mg/g; CZ, 1.83+/-0.19 mg/g) were not significantly different among the groups, nor was the calcium-magnesium ratio. These results suggest that although dietary zinc deficiency retards growth and causes bone fragility, bone deposition of calcium and magnesium and its ratio are not affected.
Assuntos
Desenvolvimento Ósseo/fisiologia , Osso e Ossos/metabolismo , Cálcio/metabolismo , Dieta , Magnésio/metabolismo , Zinco/fisiologia , Animais , Relação Dose-Resposta a Droga , Fêmur/crescimento & desenvolvimento , Masculino , Tamanho do Órgão/fisiologia , Ratos , Aumento de Peso/fisiologiaRESUMO
Zinc deficiency remains a serious health problem worldwide affecting developed as well as developing countries. Despite the evidence proving that zinc deprivation during the periods of rapid growth negatively affects the cognitive brain as well as sexual development, there are few complete studies carried out in children. The present article proposes a revision of the evidence gathered until now on the relationship existing between zinc deficiency and intellectual and sexual development during the stages of childhood, preadolescence, and adolescence.
Assuntos
Desenvolvimento Humano/fisiologia , Desenvolvimento Sexual/fisiologia , Zinco/deficiência , Animais , Sistema Nervoso Central/metabolismo , Cognição/fisiologia , Humanos , Desnutrição/fisiopatologia , Zinco/metabolismoRESUMO
Diabetes mellitus is a group of metabolic disorders, the incidence of which varies widely throughout the world. The treatment of diabetes mellitus includes insulin, oral antidiabetic agents, and dietary regimens. Although the emphasis is on macronutrients intakes, there is strong evidence that there is an abnormal metabolism of several micronutrients in diabetic individuals. Zinc is one of the essential micronutrients of which status and metabolism is altered in this condition. This work is a short review about the close relation among zinc, glucose metabolism, and insulin physiology, as well as about the few experimental data about zinc absorption and zinc supplementation in diabetes mellitus patients.
Assuntos
Diabetes Mellitus/sangue , Diabetes Mellitus/tratamento farmacológico , Zinco/farmacologia , Complicações do Diabetes , Suplementos Nutricionais , Radicais Livres , Glucose/metabolismo , Humanos , Insulina/metabolismoRESUMO
Microencapsulated ferrous sulfate with soy lecithin (SFE-171) has been used as an iron source for the fortification of milk and dairy products. With the purpose to extend the use of this agent to other kind of foods or even to pharmaceutical preparations for oral administration, the SFE-171 was turned into a fluid powder (SFE-171-P) by means of vacuum drying. The iron bioavailability (BioFe) of SFE-171-P was evaluated in this work by means of the prophylactic-preventive method in rats, using ferrous sulfate as reference standard. Both iron sources were separately added to a basal diet of low iron content in a concentration of 10 mg iron/kg diet. Two groups of 10 weaned rats 25 days old received the fortified diets during 28 days, while a third group of the same size received the basal diet without iron additions. The weights and haemoglobin concentrations (HbC) of every animal were determined before and after the treatment, thus allowing the calculation of the mass of iron incorporated into haemoglobin (HbFe) during this period. The BioFe of the iron sources were obtained as the percentage ratio between the HbFe and the mass of iron consumed by each animal. The results were also given as Relative Biological Value (RBV), which relates the BioFe of the studied source with that of the reference standard. The liver iron concentration (LIC) of each animal was determined at the end of the experiment in order to evaLuate the influence of the studied iron sources on the liver iron stores. SFE-171-P presented BioFe, RBV and LIC values of (47 +/- 7)%, 109% and (46.6 +/- 3.4) mg/kg respectively, while the corresponding values for the reference standard were of (43 +/- 7)%, 100% and (45.0 +/- 4.7) mg/kg. These results show that the drying process used to produce the SFE-171-P does not affect its bioavailability, which is also adequate for the potential use of this product in food fortification or with pharmaceutical purposes.
Assuntos
Compostos Ferrosos/farmacocinética , Ferro/farmacocinética , Fosfatidilcolinas/farmacocinética , Animais , Química Clínica/métodos , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Composição de Medicamentos , Feminino , Hemoglobinas/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
The essentiality of zinc for humans was first documented by Prasad in the 1960s. The main clinical manifestations associated with zinc deficiency are growth retardation, hypogonadism, diarrhea, and increased susceptibility to infectious diseases. Thus, in the past 25 yr, there was an increased interest of researchers in studying the role of zinc in human immunity. Although mechanistic research has been carried out using animal models, there are several studies in humans with similar results. This work is an attempt to review the information available in this field to understand the important role that zinc plays in the normal development and function of the immune system.
Assuntos
Sistema Imunitário/fisiologia , Estado Nutricional , Zinco/metabolismo , Idoso , Animais , Criança , Humanos , Timo/metabolismo , Timo/fisiologiaRESUMO
Food fortification with a proper zinc compound is an economic and effective strategy to prevent zinc deficiency. BioZn-AAS, a zinc gluconate stabilized with glycine, was compared with zinc sulfate (reference standard), zinc hydroxide, and zinc gluconate, all of them labeled with (65)Zn. This preclinical study was performed on Sprague-Dawley rats of both sexes, and the administered dose was 85 microg/kg of zinc. Bioavailability studies showed that absorption of BioZn-AAS was not statistically different than absorption from other sources in female rats (25.65% +/- 2.20% for BioZn-AAS, 28.24% +/- 4. 60% for ZnSO(4), 24.91% +/- 4.02% for Zn[OH](2), and 25.51% +/- 2. 70% for Zn-gluconate). In the case of the male rats, absorption of BioZn-AAS (27.97% +/- 4.20%) was higher (P<0.05) than that from the other compounds (23.15% +/- 2.90% for ZnSO(4), 22.62% +/- 3.90% for Zn[OH](2), and 22.30% +/- 3.90% for Zn-gluconate). Biodistribution studies demonstrated that the zinc from BioZn-AAS followed the same metabolic pathway as zinc from the other sources. Toxicity studies were performed with 50 female and 50 male rats. The value of oral lethal dose 50 (LD(50)) was 2000 mg/kg for female rats and 1900 mg/kg for male rats. Therefore, we conclude that BioZn-AAS has adequate properties to be considered a proper zinc compound for food fortification or dietary supplementation.