Mutagenic Evaluation of Fluoxetine and Fluoxetine-Galactomannan Complex Through the Analysis of Chromosomal Aberrations in Human Peripheral Leukocytes and Salmonella typhimurium/Microssome Assay / Avaliação Mutagênica de Fluoxetina e Complexo Fluoxetina-Galactomanana Através da Análise de Aberrações Cromossômicas em Leucócitos Periféricos Humanos e em Salmonella typhimurium / Ensaio Microssômico

Objectives: The purpose of this study was to evaluate the mutagenic potential of fluoxetine and fluoxetine-galactomannan. Methods: Chromosomal aberration test and Salmonella typhimurium/microsome mutagenicity assay. Results: The results showed that fluoxetine (250 µg/mL) can cause chromosomal breaks of treated leukocytes and increase the frequency of reversion of the tester strains of S. typhimurium / microsome assay only at the highest concentration (5 mg/mL), while fluoxetine encapsulated in galactomannan did not cause these changes (leukocytes and S. typhimuriums strains). Conclusion: In summary, fluoxetine showed a mutagenic effect detectable only at high concentrations in both eukaryotic and prokaryotic models. Furthermore, the fluoxetine/galactomannan complex, in this first moment, prevented the mutagenicity attributed to fluoxetine, emphasizing that the present encapsulation process can be an alternative in preventing these effects in vitro.

Objetivos: avaliar o potencial mutagênico da fluoxetina e da fluoxetina-galactomanana. Métodos: Teste de aberração cromossômica e ensaio de mutagenicidade de Salmonella typhimurium /microssoma. Resultados: a fluoxetina (250 µg/mL) pode causar quebras cromossômicas de leucócitos tratados e aumentar a frequência de reversão das cepas testadoras de S. typhimurium /microssoma apenas na concentração mais alta (5 mg/mL), enquanto a fluoxetina encapsulada em galactomanano não causou essas alterações (leucócitos e cepas de S. typhimurium). Conclusão: a fluoxetina mostrou um efeito mutagênico detectável apenas em altas concentrações em modelos eucarióticos e procarióticos. Além disso, o complexo fluoxetina/galactomanan, neste primeiro momento, evitou a mutagenicidade atribuída à fluoxetina, ressaltando que o presente processo de encapsulamento pode ser uma alternativa na prevenção desses efeitos in vitro.

Evaluation of frequency of autoimmune hepatitis autoantibodies in children with type 1 diabetes / Frecuencia de anticuerpos de hepatitis autoinmune en niños con diabetes tipo I

Background: Diabetes mellitus type 1 (T1DM) is one of the childhood diseases with growing prevalence. Various accompanying autoimmune diseases were seen with type 1 diabetes. The most common autoimmune diseases with T1DM are autoimmune thyroiditis and celiac disease. In some reports, autoimmune hepatitis has been reported in association with DM-1. Objectives: The aim of this study was to evaluate autoimmune hepatitis autoantibodies in children with T1DM. Materials and methods: In this crosssectional study, 202 children with T1DM were evaluated (47.5% were males and 52.5% were girls). Liver enzymes, autoimmune hepatitis related autoantibodies such as anti-nuclear antibodies (ANA), anti-smooth muscle (ASMA) and anti liver and kidney microsomal antibodies (LKM-1) were measured. Liver ultrasound was done for participants and biopsy of liver was taken for children with increased echogenicity of the liver, hepatomegaly or elevated liver enzymes. Results analyzed by statistical software spss-16, Descriptive statistics and chi-square test, paired T-TEST. Level of less than 5% was considered statistically significant. Results: In 6 patients ANA and in 4 patients (2%) ASMA was positive,1 patient was ASMA positive but ANA negative. None of the patients were Anti LKM-1 positive. 3 patients had positive ANA and ASMA, and increased liver echogenicity on ultrasound simultaneously. Histological evaluation was showed that 2 patients had findings in favor of autoimmune hepatitis. Conclusion: Auto antibodies were positive in 10 cases. ANA was positive in 6 (2.97%) of all cases. ASMA was positive in 4 (1.98%) cases. Increased echogenicity was found in 3 cases. Histological evaluation showed 2 patients had biopsy confirmed autoimmune hepatitis. AIH-2 was not seen among our cases.

Antecedentes: La diabetes mellitus tipo 1 (DM1) es una de las enfermedades infantiles con mayor prevalencia. Se observaron varias enfermedades autoinmunes acompañantes con diabetes tipo 1. Las enfermedades autoinmunes más comunes con DM1 son la tiroiditis autoinmune y la enfermedad celíaca. En algunos reportes, se ha encontrado hepatitis autoinmune en asociación con DM-1. Objetivos: El objetivo de este estudio fue evaluar los autoanticuerpos de hepatitis autoinmunes en niños con DM1. Materiales y métodos: En este estudio transversal, se evaluaron 202 niños con DM1 (47,5% eran hombres y 52,5% eran niñas). Se midieron las enzimas hepáticas, los autoanticuerpos autoinmunes relacionados con la hepatitis, como los anticuerpos antinucleares (ANA), el músculo liso (ASMA) y los anticuerpos microsomales hepáticos y renales (LKM-1). Se realizó una ecografía hepática para los participantes y se tomó una biopsia del hígado para niños con mayor ecogenicidad del hígado, hepatomegalia o enzimas hepáticas elevadas. Los resultados fueron analizados por el software estadístico spss-16 usando estadística descriptiva y prueba de chi-cuadrado, T-TEST pareado. Se consideró estadísticamente significativo un nivel menor del 5%. Resultados: En 6 pacientes con ANA y en 4 pacientes (2%) ASMA fue positiva, 1 paciente fue ASMA positiva pero ANA negativa. Ninguno de los pacientes fue anti LKM-1 positivo. 3 pacientes tuvieron ANA y ASMA positivas, y aumentaron la ecogenicidad hepática en la ecografía simultáneamente. La evaluación histológica mostró que 2 pacientes tenían hallazgos a favor de la hepatitis autoinmune. Conclusión: Los autoanticuerpos fueron positivos en 10 casos. ANA fue positivo en 6 (2,97%) de todos los casos. La ASMA fue positiva en 4 (1,98%) casos. Se encontró mayor ecogenicidad en 3 casos. La evaluación histológica mostró que 2 pacientes tenían biopsia confirmada de hepatitis autoinmune. AIH-2 no fue visto entre nuestros casos.

Biotransformation of bromhexine by Cunninghamella elegans, C. echinulata and C. blakesleeana

Abstract Fungi is a well-known model used to study drug metabolism and its production in in vitro condition. We aim to screen the most efficient strain of Cunninghamella sp. among C. elegans, C. echinulata and C. blakesleeana for bromhexine metabolites production. We characterized the metabolites produced using various analytical tools and compared them with mammalian metabolites in Rat liver microsomes (RLM). The metabolites were collected by two-stage fermentation of bromhexine with different strains of Cunninghamella sp. followed by extraction. Analysis was done by thin layer chromatography, high performance thin layer chromatography, Fourier transform infrared spectroscopy, high performance liquid chromatography and Liquid chromatography–mass spectrometry. The role of Cytochrome P3A4 (CYP3A4) enzymes in bromhexine metabolism was studied. Fungal incubates were spiked with reference standard – clarithromycin to confirm the role of CYP3A4 enzyme in bromhexine metabolism. Three metabolites appeared at 4.7, 5.5 and 6.4 min retention time in HPLC. Metabolites produced by C. elegans and RLM were concluded to be similar based on their retention time, peak area and peak response of 30.05%, 21.06%, 1.34%, and 47.66% of three metabolites and bromhexine in HPLC. The role of CYP3A4 enzyme in metabolism of bromhexine and the presence of these enzymes in Cunninghamella species was confirmed due to absence of peaks at 4.7, 5.4 and 6.7 min when RLM were incubated with a CYP3A4 enzyme inhibitor – clarithromycin.

Role of 11â-hydroxysteroid dehydrogenase 2 renal activity in potassium homeostasis in rats with chronic renal failure

Aldosterone concentrations vary in advanced chronic renal failure (CRF). The isozyme 11â-hydroxysteroid dehydrogenase 2 (11â-HSD2), which confers aldosterone specificity for mineralocorticoid receptors in distal tubules and collecting ducts, has been reported to be decreased or normal in patients with renal diseases. Our objective was to determine the role of aldosterone and 11â-HSD2 renal microsome activity, normalized for glomerular filtration rate (GFR), in maintaining K+ homeostasis in 5/6 nephrectomized rats. Male Wistar rats weighing 180-220 g at the beginning of the study were used. Rats with experimental CRF obtained by 5/6 nephrectomy (N = 9) and sham rats (N = 10) were maintained for 4 months. Systolic blood pressure and plasma creatinine (Pcr) concentration were measured at the end of the experiment. Sodium and potassium excretion and GFR were evaluated before and after spironolactone administration (10 mg·kg-1·day-1 for 7 days) and 11â-HSD2 activity on renal microsomes was determined. Systolic blood pressure (means ± SEM; Sham = 105 ± 8 and CRF = 149 ± 10 mmHg) and Pcr (Sham = 0.42 ± 0.03 and CRF = 2.53 ± 0.26 mg/dL) were higher (P < 0.05) while GFR (Sham = 1.46 ± 0.26 and CRF = 0.61 ± 0.06 mL/min) was lower (P < 0.05) in CRF, and plasma aldosterone (Pald) was the same in the two groups. Urinary sodium and potassium excretion was similar in the two groups under basal conditions but, after spironolactone treatment, only potassium excretion was decreased in CRF rats (sham = 0.95 ± 0.090 (before) vs 0.89 ± 0.09 µEq/min (after) and CRF = 1.05 ± 0.05 (before) vs 0.37 ± 0.07 µEq/min (after); P < 0.05). 11â-HSD2 activity on renal microsomes was lower in CRF rats (sham = 0.807 ± 0.09 and CRF = 0.217 ± 0.07 nmol·min-1·mg protein-1; P < 0.05), although when normalized for mL GFR it was similar in both groups. We conclude that K+ homeostasis is ...

Evaluation of extracts from Coccoloba mollis using the Salmonella/microsome system and in vivo tests

The common everyday use of medicinal plants is an ancient, and still very widespread practice, whereby the need for studies on their possible toxicity and mutagenic properties. The species Coccoloba mollis has been much used in phytotherapy, mainly in cases involving loss of memory and stress. In order to investigate its genotoxic and mutagenic potential, ethanolic extracts from the leaves and roots underwent Salmonella/microsome assaying (TA98 and TA100 strains, with and without exogenous metabolism - S9), besides comet and micronucleus tests in vivo.There was no significant increase in the number of revertants/plate of Salmonella strains in any of the analyzed root-extract concentrations, although the extract itself was extremely toxic to the Salmonella TA98 strain in the tests carried out with S9 (doses varying from 0.005 to 0.5 µg/plate). On the other hand, the leaf-extract induced mutations in the TA98 strain in the absence of S9 in the highest concentration evaluated, although at very low mutagenic potency (0.004 rev/µg). Furthermore, there was no statistically significant increase in the number of comets and micronuclei, in treatments involving Swiss mice. It was obvious that extracts of Coccoloba mollis, under the described experimental conditions, are not mutagenic.

Benznidazole biotransformation in rat heart microsomal fraction without observable ultrastructural alterations: comparison to Nifurtimox-induced cardiac effects

Benznidazole (Bz) and Nifurtimox (Nfx) have been used to treat Chagas disease. As recent studies have de-monstrated cardiotoxic effects of Nfx, we attempted to determine whether Bz behaves similarly. Bz reached the heart tissue of male rats after intragastric administration. No cytosolic Bz nitroreductases were detected, although microsomal NADPH-dependent Bz nitroreductase activity was observed, and appeared to be mediated by P450 reductase. No ultrastructurally observable deleterious effects of Bz were detected, in contrast to the overt cardiac effects previously reported for Nfx. In conclusion, when these drugs are used in chagasic patients, Bz may pose a lesser risk to heart function than Nfx when any cardiopathy is present.

Glucosa-6-fosfatasa de envoltura nuclear de hígado de rata / Glucose-6-phosphatase from nuclear envelope in rat liver

Se comparó la actividad de la glucosa-6-fosfatasa (G-6-Pasa) de envoltura nuclear (EN) con la microsomal. Los microsomas intactos fueron incapaces de hidrolizar manosa-6-fosfato (M-6-P); por el contrario, la EN intacta fue capaz de hidrolizar dicho substrato. La galactosa-6-fosfato mostró ser un buen substrato tanto para la enzima de EN como microsomal, con una latencia similar a la obtenida para M-6-P utilizando microsomas, por lo cual galactosa-6-fosfato fue usado para medir el porcentaje de EN intactas. Los parámetros cinéticos (Kii y Kis) de la inhibición por floricina de la G-6-Pasa de EN intactas, utilizando glucosa-6-fosfato (G-6-P) y M-6-P como substrato, fueron aproximadamente iguales. El transportador T1 de EN fue más sensible a la amiloride que el microsomal. Por el contrario, el sistema microsomal fue más sensible al efecto de N-etilmaleimida (NEM) que el de EN y este último, fue prácticamente insensible a los inhibidores de transporte aniónico DIDS y SITS, los cuales afectan fuertemente la enzima microsomal. Los resultados anteriores permiten sugerir que en la EN existe un transportador de hexosas-6-fosfato, capaz de transportar G-6-P y M-6-P y quizás otras hexosas-6-fosfato y que, o es diferente al T1 microsomal, o si es igual es influenciado por las características del sistema membranoso en el cual está incluido. La capacidad superior de hidrólisis de PPi de la G-6-Pasa de EN intacta, en comparación con la de microsomas intactos, sugiere diferencias en el transportador de Pi/PPi (T2) de ambos sistemas. La menor sensibilidad de la G-6-Pasa de EN al NEM sugiere que la subunidad catalítica de este sistema también podría tener algunas diferencias con la isoforma microsomal.

Genotoxicidad de Justicia pectoralis Jacq: (tilo) / Genotocixity of Justicia pectoralis Jacq: (tilo)

Objetivo: determinar el efecto genotóxico del extracto hidroalcohólico 30 por ciento de partes aéreas de Justicia pectoralis Jacq. (variedad pectoralis) secado por spray dryer. Métodos: se empleó el ensayo Salmonella/microsomas con las líneas TA 1535, TA 1537, TA 98 y TA 100 con un rango de concentraciones de 50 a 5 000 mg de polvo/placa (± S9) según el protocolo de incorporación en placas; para el ensayo de micronúcleos en médula ósea se utilizaron ratones Cenp: NMRI de los 2 sexos, que recibieron dosis isovolumétricas (10 mL/kg) de 500, 1 000 y 2 000 mg de polvo/kg, por vía intragástrica, separadas 24 h, con sacrificio 24 h después de la última aplicación. Resultados: no se encontró efecto genotóxico con ninguna de las cepas en el ensayo de Salmonella/microsomas y el extracto no causó un aumento estadísticamente significativo en la frecuencia de eritrocitos policromáticos micronucleados en los ratones tratados y no mostró relación dosis respuesta positiva. Conclusiones: el polvo no reveló efecto genotóxico en las condiciones experimentales de este estudio.

Objective: to detemine the genotoxic effect of the hydroalcoholic extract 30 of aerial parts of Justicia pectoralis Jacq. (variety pectoralis) dried by spray drier. Methods: the Salmonella/microsomes with lines TA 1535, TA 1537, TA 98 and TA 100 with a concentration range from 50 to 5 000 ìg of powder/plaque (± S9) was used according to the protocol of incorporation in plaques; for the bone marrow micronucleus assay there were used Cenp mice: NMRI of both sexes that received isovolumetric doses (10 mL/kg) of 500, 1 000 y 2 000 mg of powder/kg by intragastric route at intervals of 24 h and were sacrificed 24 h after the last application. Results: no genotoxic effect was found with any of the strains in the assay of Salmonella/microsomes. The extract did not cause a statistically significant increase in the frequency of micronucleated polychromatic erythrocytes in the mice treated. No dose/positive response relation was observed. Conclusions: the powder did not reveal genotoxic effect under the experimental conditions of this.

Prevalência de anticorpos antimicrossomais em pacientes com esclerose múltipla / Prevalence of antimicrosomal antibodies in patients with multiple sclerosis

O objetivo deste estudo consiste em avaliar a prevalência de anticorpos antimicrossomais (AAM), a função tireóidea e a ocorrência de sintomas relacionados ao hipotireoidismo em pacientes com esclerose multipla (EM). Em um grupo de 21 pacientes com EM, foi realizado exameclínico, foram dosados o TSH, T4 e T4 livre e pesquisados AAM. A média de idade foi 41,05 anos e a média de tempo de doença foi 85,9 meses. Os sintomas relacionados ao hipotireoidismo foram fadiga, fraqueza, letargia e parestesias. Os AAM foram encontrados em 4 pacientes (19 por cento). O tempo de doença foi dividido em três períodos: <60 meses (3 pacientes AAM+/7AAM-), 60-120 meses (8 pacientes AAM-) e >120 meses (1 paciente AAM+/2 AAM-). Dois pacientes apresentaram níveis de T4 livre diminuídos, porém com T4 e TSH normais. Em 1 paciente, constatou-se hipotireoidismo subclínico, e em outro, hipotireoidismo clássico. Conclui-se que na avaliação dos pacientes com EM, em vista da falta de precisão na avaliação clínica do hipotireoidismo ocasionada pela sobreposição de sintomas referentes à EM, devam ser incorporadas as dosagens das provas de função tireóidea (PFT) e dos AAM.

Abnormal subcellular distribution of GLUT4 protein in obese and insulin-treated diabetic female dogs

The GLUT4 transporter plays a key role in insulin-induced glucose uptake, which is impaired in insulin resistance. The objective of the present study was to investigate the tissue content and the subcellular distribution of GLUT4 protein in 4-to 12-year-old control, obese and insulin-treated diabetic mongrel female dogs (4 animals per group). The parametrial white adipose tissue was sampled and processed to obtain both plasma membrane and microsome subcellular fractions for GLUT4 analysis by Western blotting. There was no significant difference in glycemia and insulinemia between control and obese animals. Diabetic dogs showed hyperglycemia (369.9 ± 89.9 mg/dl). Compared to control, the plasma membrane GLUT4, reported per g tissue, was reduced by 55 percent (P < 0.01) in obese dogs, and increased by 30 percent (P < 0.05) in diabetic dogs, and the microsomal GLUT4 was increased by approximately 45 percent (P < 0.001) in both obese and diabetic animals. Considering the sum of GLUT4 measured in plasma membrane and microsome as total cellular GLUT4, percent GLUT4 present in plasma membrane was reduced by approximately 65 percent (P < 0.001) in obese compared to control and diabetic animals. Since insulin stimulates GLUT4 translocation to the plasma membrane, percent GLUT4 in plasma membrane was divided by the insulinemia at the time of tissue removal and was found to be reduced by 75 percent (P < 0.01) in obese compared to control dogs. We conclude that the insulin-stimulated translocation of GLUT4 to the cell surface is reduced in obese female dogs. This probably contributes to insulin resistance, which plays an important role in glucose homeostasis in dogs.

Standardization of conditions for the metabolic activation of N-nitrosodiethylamine in mutagenicity tests

Like all nitrosamines, N-nitrosodiethylamine (NDEA) requires metabolic activation in order to exert its carcinogenic effects. This activation involves cytochrome P450s (CYP), which generates unstable metabolites that react with the DNA of cells in the immediate vicinity of metabolite formation. Although NDEA is carcinogenic, it has been considered a weak mutagen in classic genotoxicity assays. We used optimized Salmonella/mammalian microsome genotoxicity assays to assess the mutagenicity and toxicity of low concentrations of NDEA. Using a fixed concentration of NDEA (36.5 mg/ml), we varied the length of preincubation in the presence of different concentrations of an S9 metabolic activation mixture. Salmonella typhimurium strains TA97 and TA102 were resistant to NDEA-induced mutagenesis, even after a preincubation of up to 120 min and the use of different concentrations of the S9 mix. Strain TA98 was susceptible to mutagenesis by NDEA in the absence of the S9 mix and after preincubation with NDEA for 90 min. When bacteria of this strain were preincubated with NDEA for 60 min, mutagenesis was detected at an S9 mix concentration >9.55 mg/ml. NDEA also induced mutagenesis in strain TA100 after preincubation for 90 or 120 min, and this effect was dependent on the S9 concentration. E. coli strain BH990 also showed a concentration-dependent response, with only 60% of the cells surviving after a 120-min preincubation with NDEA in the presence of 19.1 mg S9 mix/ml.

Morphologic and biochemical changes in male rat lung after surgical and pharmacological castration

The morphology of the rat lung was studied by light microscopy in different situations: after surgical and pharmacological castration and after administration of testosterone to the castrated rat to determine if the androgen is required to maintain the normal morphology of the lung. We also determined the effect of flutamide on the phospholipid composition of both the surfactant and microsomes of the lung. Rats were separated into five groups: I - control non-castrated rats, II - castrated rats sacrificed 21 days after castration, III - castrated rats that received testosterone daily from day 2 to day 21 after castration, IV - castrated rats that received testosterone from day 15 to day 21 after castration, and V - control rats injected with flutamide for 7 days. The amount of different phospholipids in the surfactant and microsomes of the lung was measured in group I and V rats. At the light microscopy level, the surgical and pharmacological castration provoked alterations in the morphology of the lung, similar to that observed in human lung emphysema. The compositions of surfactant and microsomes of the lung were similar to those previously reported by us for the surgically castrated rats. These results indicate that androgens are necessary for the normal morphology as well as for some metabolic aspects of the lung.

Inhibition of rat microsomal lipid peroxidation by the oral administration of D002

The effect of D002, a defined mixture of higher primary alcohols purified from bee wax, on in vivo and in vitro lipid peroxidation was studied. The extent of lipid peroxidation was measured on the basis of the levels of thiobarbituric acid reactive substances (TBARS). When D002 (5-100 mg/kg body weight) was administered orally to rats for two weeks, a partial inhibition of the in vitro enzymatic and non-enzymatic lipid peroxidation was observed in liver and brain microsomes. Maximal protection (46 percent) occurred at a dose of 25 mg/kg. D002 behaved differently depending on both the presence of NADPH and the integrity of liver microsomes, which suggests that under conditions where microsomal metabolism was favored the protective effect of D002 was increased. D002 (25 mg/kg) also completely inhibited carbon tetrachloride- and toluene-induced in vivo lipid peroxidation in liver and brain. Also, D002 significantly lowered in a dose-dependent manner the basal level of TBARS in liver (19-40 percent) and brain (28-44 percent) microsomes. We conclude that the oral administration of D002 (5, 25 and 100 mg/kg) for two weeks protected rat liver and brain microsomes against microsomal lipid peroxidation in vitro and in vivo. Thus, D002 could be useful as a dietary natural antioxidant supplement. More studies are required before these data can be extrapolated to the recommendation for the use of D002 as a dietary antioxidant supplement for humans

Prevalencia de anticuerpos antitiroglobulina y antimicrosomales en enfermedad tiroidea autoinmune / Antithyroglobulin and microsomal antibodies prevalence in autoimmune thyroid disease

Objetivo: Analizar la prevalencia de anticuerpos antitiroideos en enfermedades tiroideas, su relación con variables clínicas y epidemiológicas, y su utilidad diagnóstica. Métodos: Se determinaron anticuerpos antimicrosomales y antitiroglobulina por aglutinación de partículas de gelatina en 32 pacientes sanos (25 mujeres, 7 hombres) y 108 (92 mujeres, 16 hombres) con enfermedad tiroidea; diagnosticados por examen clínico, confirmados por laboratorio y cuando fue necesario por ecografía, pruebas de captación, biopsia y otras. Se consideró la patología, edad y sexo de los pacientes. Resultados: Las enfermedades tiroideas autoinmunitarias predominaron sobre las no autoinmunes en la población estudiada, 64,8 por ciento vs 35,2 por ciento. Los anticuerpos antimicrosomales fueron positivos en altos títulos en la mayoría de los pacientes con enfermedad de Graves y Hashimoto, mientras que pacientes con enfermedades tiroideas no autoinmune presentaron baja frecuencia. La prevalencia de anticuerpos anti tiroglobulina en enfermedades tiroideas autoinmunes fue significativamente menor a la de antimicrosomales, (44,3 por ciento vs 98,6 por ciento p<0,05). Aunque no fue estadísticamente significativo, se encontró cierta asociación entre enfermedades tiroideas autoinmunes y otros desórdenes autoinmunes (Enfermedad de Addison) y no autoinmunes (Diabetes mellitus tipo II). No hubo relación entre parotiditis previa y autoinmunidad tiroidea. Los anticuerpos antimicrosomales mostraron mayor sensibilidad que los antitiroglobulina (98,6 por ciento y 44,3 por ciento), con especificidad comparable (85,7 por ciento y 95,7 por ciento). Conclusiones: Debido a la mayor prevalencia y sensibilidad presentada por los anticuerpos antimocrosomales, el diagnóstico de tiroiditis autoinmune podría basarse en la valoración de dichos anticuerpos, con determinación de anticuerpos antitiroglobulina en casos especiales. Existen factores hereditarios involucrados en el desarrollo de enfermedades autoinmunes tiroideas

Effect of methyl-prednisone and cyclosporine on the lipid pattern and polyunsaturated fatty acid biosynthesis in the rat

The hyperlipidemia posttransplant has been largely attributed to immunosuppressant agents. In the present work we evaluated the effect of oral administration of cyclosporine (5 mg/kg/day) and/or methyl1-prednisone (1 mg/kg/day) on lipid composition and polyunsaturated fatty acid biosynthesis in normal adult male rats. The results obtained showed that both agents produced a delay on the growth together with a significant loss of body weight. In liver microssomal fraction from rats treated with methyl1-prednisone, a depression in delta 6 and delta 5 desaturation activited, was observed. This effect was corroborated in the fatty acid pattern through the enhancement of linoleic and dihomo-gamma-linolenic acids, and a depression of arachidonic acid. Similar results were noticed in those rats treated with both drugs when compared to the controls. No changes were observed either in the amount of liver microsomal total lipids or in the fatty acid composition of kidney and testis microsomes, as well as in erythrocyte membranes, among the different groups studied. Cyclosporine alone produced a significant depression in plasma triglycerides and showed no modifications in the other lipid parameters studied compared to the controls. Fluorescence anisotropy measured in the different membranes was not modified by the several treatments used. In view of the aforementioned data, in can be stated that methyl-prednisone would be the responsible for many of the lipid disorders that can be observed in posttransplant patients when they are subjected to the combined immunotherapy with cyclosporine.

Effect of calcium deficiency on acyl-CoA synthetase activity in microsomes from various rat tissues

The specific activity of long-chain acyl-CoA synthetase in microsomes from various tissues of control and calcium-deficient rats was determined. It was found that the saturated acids, palmitic and stearic, were preferential substrates compared to the non-saturated linoleic, alpha-linolenic and eicosa-8,11,14-trienoic acids. All of them showed similar Vm values with different affinity constants. After 60-day treatment on a calcium-deficient diet (0.5 g Ca/kg diet), a significant increase in the acyl-CoA synthetase activity was observed for all the tested fatty acids in liver and kidney microsomes. These changes were e voked without any modification in the substrate selectivities shown for the control microsomes, and they were well-correlated with calcium level in both tissues. Under the calcium deficient state an increase in Vm values was observed for palmitic and eicosatrienoic acids with no changes in the corresponding Km, suggesting an increment in the number of active enzyme molecules within the microsomal membrane.

Effects of estradiol benzoate on 5'-iodothyronine deiodinase activities in female rat anterior pituitary gland, liver and thyroid gland

There is little information on the possible effects of estrogen on the activity of 5'-deiodinase (5'-ID), an enzyme responsible for the generation of T3, the biologically active thyroid hormone. In the present study, anterior pituitary sonicates or hepatic and thyroid microsomes from ovariectomized (OVX) rats treated or not with estradiol benzoate (EB, 0.7 or 14 mug/100 g body weight, sc, for 10 days) were assayed for type I 5'-ID (5'-ID-I) and type II 5'-ID (5'-ID-II, only in pituitary) activities. The 5'-ID activity was evaluated by the release of (125)I from deiodinated (125)I rT3, using specific assay conditions for type I or type II. Serum TSH and free T3 and free T4 were measured by radioimmunoassay. OVX alone induced a reduction in pituitary 5'-ID-I (control = 723.7 + 67.9 vs OVX = 413.9 + 26.9; P<0.05), while the EB-treated OVX group showed activity similar to that of the normal group. Thyroid 5'-ID-I showed the same pattern of changes, but these changes were not statistically significant. Pituitary and hepatic 5'-ID-II did not show major alterations. The treatment with the higher EB dose (14 mug), contrary to the results obtained with the lower dose, had no effect on the reduced pituitary 5'-ID-I of OVX rats. However, it induced an imporatnt increment of 5'-ID-I in the thyroid gland (0.8 times higher than that of the normal group: control = 131.9 + 23.7 vs OVX + EB 14 mug = 248.0 + 31.2; P<0.05), which is associated with increased serum TSH (0.6-fold vs OVX, P<0.05) but normal serum free T3 and free T4. The data suggest that estrogen is a physiological stimulator of anterior pituitary 5'-ID-I and a potent stimulator of the thyroid enzyme when employed at high doses.

The effect of diazepan and exercise training on selected biochemical and histochemical properties of rat skeletal muscle

The effects of chronic diazepan (D) treatment and exercise training on total body mass (TBM), microsomal protein yield (MPY), calcium uptake by fragmented sarcoplasmic reticulum (SR), muscle fibre cross-sectional area, and both PFK and SDH activities were investigated in the tibialis anterior (TA), soleus (Sol), and plantaris (Plt) muscles of 50 male albino Sprague-Dawley rats. Rats were assigned randomly to control (C), sprint-trained (S), or endurance-trained (E) groups. Training was of 12 weeks duration. One-half of each group received daily intraperitoneally D doses of 5 mg kg(-1) of TBM. Exercise reduced TBM (p<0.05); increased the relative BM of the TA (E=2.02+0.02, p<0.01) and Plt (E=1.15+0.02, p<0.01; S=1.13+0.03, p<0.01), as well as the Ca++ uptake of the Sol SR (C=0.08+0.02, E=0.16+01, p<0.05). MPY was elevated in S-Sol (C=1.12+0.6, S=1.52+0.1, p<0.01). Delevated Sol MPY as well as TA PFK. S-trained animals had lower mean fibre areas than the E-trained (D-treated and untreated) animals. The elevated relative masses of TA and Plt are explained by a decreased TBM with exercise. The increased Ca++ uptake of the Sol indicates that E enhances this function, and the increased MPY probably implies an increased SR. The D could be responsible for the D-elevated Sol MPY as well as the TA PFK. El D did not reduce neuromuscular activity to a level adversely affecting oxidative enzyme activity, but in the case of PFK activity in the TA muscle, such a reduction was evident.

Effect of policosanol on the hepatic cholesterol biosynthesis of normocholesterolemic rats

We have suggested previously, measuring 14C-acetate incorporation into free cholesterol, that oral administration of policosanol inhibits hepatic cholesterol biosynthesis in rats. Nevertheless, since acetate has limitations to study cholesterol synthesis in vivo, we now investigate rates of incorporation of labeled water into hepatic sterol after policosanol treatment. Absolute rates of incorporation of 3H-water in sterols were depressed by policosanol by about 20 percent, giving a more accurate degree of cholesterol biosynthesis inhibition in this species. Since policosanol did not inhibit labeled mevalonate incorporation into cholesterol in rat liver, we also studied the effect of policosanol on hydroxy-methylglutaryl-coenzyme A (HMG-CoA) reductase. Reductase activity assayed in microsomes treated with policosanol remained unchanged, suggesting that cholesterol synthesis is not inhibited by a direct action of policosanol on this enzyme