Effects of dexamethasone on the morphometry and biometry of immune organs of broiler chicken / Efectos de la dexametasona en la morfometría y biometría de los Órganos Inmunes del pollo de engorde

The study was conducted to examine the histological changes i.e. morphology and biometry of immune organs (thymus, spleen and bursa cloacalis or «Fabricius¼) of broilers in response to dietary dexamethasone (DEX). The day old chicks were obtained from the commercial hatchery and randomly divided into two groups i.e. control and experimental or treated group. The control group was reared on commercial broiler ration and the experimental group (n=25) was maintained on commercial broiler ration with corticosteroid (Dexamethasone-Decason, BP 0.5 mg, Opsonin @ 7 mg/kg feed). Samples (bursa cloacalis, spleen, and thymus) were collected from the ten control and ten experimental broilers at 14 and 28 days of experiment; then tissues were stained with Hematoxylin and Eosin. The biometric measurements of the samples were performed by the calibrated stage micrometer. Finally, the obtained data were analyzed using GraphPad Prism 8 software. In DEX treated group, the morphology of thymus, spleen and bursa cloacalis did not show any abnormal alterations. But their development rate was slower on visual inspection in DEX treated group. The length and width of bursal follicle of bursa cloacalis, thymic lobule of thymus and white pulp of spleen were statistically consisted but numerically decreased in DEX treated group than the control. The present findings suggested that DEX does not affect the histological architectures of immune organs except causing developmental arrest. Numerical decrease in the biometry of immune organs indicates that DEX causes apoptosis of immune cells in lymphoid organs of broiler.

El estudio se realizó para examinar los cambios histológicos, es decir, la morfología y la biometría de los órganos inmunes (timo, bazo y bolsa cloacal) de pollos de engorde en respuesta a la dexametasona en la dieta (DEX). Los pollitos de un día se obtuvieron de un criadero comercial y se dividieron aleatoriamente en dos grupos, control y experimental. El grupo control se crió con una ración comercial de pollos de engorde y el grupo experimental (n = 25) se mantuvo con una ración comercial de pollos de engorde con corticosteroides (DexamethasoneDecason, BP 0,5 mg, Opsonin @ 7 mg/kg). Se recogieron muestras (bolsa cloacal, bazo y timo) de los diez pollos del grupo control y diez del grupo de engorde experimental, a los 14 y 28 días de experimento. Luego, los tejidos se tiñeron con hematoxilina y eosina. Las mediciones biométricas de las muestras fueron realizadas con un micrómetro calibrado. Finalmente, los datos obtenidos se analizaron utilizando el software GraphPad Prism 8. En el grupo tratado con DEX, la morfología del timo, el bazo y la bolsa cloacal no mostraron alteraciones anormales. Pero su tasa de desarrollo fue más lenta en la inspección visual en el grupo tratado con DEX. La longitud y el ancho del folículo bursal de la bolsa cloacal, el lóbulo tímico del timo y la pulpa blanca del bazo fueron estadísticamente consistentes, pero disminuyeron numéricamente en el grupo tratado con DEX en relación al control. Los hallazgos actuales sugirieron que DEX no afecta la arquitectura histológica de los órganos inmunes, excepto que causa una detención del desarrollo. La disminución numérica en la biometría de los órganos inmunes indica que DEX provoca apoptosis de las células inmunes en los órganos linfoides de los pollos de engorde.

In vivo redox effects of Aspidosperma quebracho-blanco Schltdl., Lantana grisebachii Stuck and Ilex paraguariensis A. St.-Hil. on blood, thymus and spleen of mice.

Argentinian native plants Aspidosperma quebracho-blanco, Lantana grisebachii and Ilex paraguariensis are known to have antiinflammatory and antioxidant properties. We demonstrated it in vivo by the redox changes in murine hemolymphatic tissues after infusive extract intake of these plants as revealed in organic trophism, tissue phenolics, hydroperoxides, superoxide, nitrites and γ-glutamyltranspeptidase in thymus, blood and spleen. A. quebracho-blanco reduced hydroperoxidation in blood and spleen of both sexes, with γ-glutamyltranspeptidase negativization in lymphatic organs and thymic nitrosative up-regulation. Males have shown increased phenolic content in blood after treatment. L. grisebachii and I. paraguariensis treatment exhibited incomplete antioxidation and oxidative induction in the studied tissues. Different results according to sex were found in redox response to phenolics and their kinetics, with males showing antioxidant effects, whereas females showed oxidative susceptibility. A. quebracho-blanco exhibited protection of murine tissues against oxidation in both sexes and modulation of their trophism, supporting its therapeutic uses in inflammatory diseases. Also, gender had significant influence in phenolic biodistribution and redox response.

Preferential recognition of methylglyoxal-modified calf thymus DNA by circulating antibodies in cancer patients.

Methylglyoxal (MG) has been implicated in mutagenesis and cancer. Present study probes the antigenicity of MG damaged DNA in cancer patients. Purified calf thymus DNA was damaged by the synergistic action of MG, lysine (Lys) and CuSO4 for 24 h at 37oC. DNA modifications produced single-strand breaks, hyperchromicity in UV spectrum and increased fluorescence intensity. Binding characteristics of auto-antibodies in cancer patients were assessed by direct binding and inhibition ELISA. These antibodies exhibited enhanced binding with the modified DNA, as compared to the native form. The effect was more pronounced when affinity-purified IgG was used in place of the serum. In conclusion, MG-modified DNA presents unique epitopes which are recognized as non-self by the immune system and may, therefore, be one of the factors for the autoantibody induction in cancer patients.

Glucocorticoids, master modulators of the thymic catecholaminergic system?

There is evidence that the major mediators of stress, i.e., catecholamines and glucocorticoids, play an important role in modulating thymopoiesis and consequently immune responses. Furthermore, there are data suggesting that glucocorticoids influence catecholamine action. Therefore, to assess the putative relevance of glucocorticoid-catecholamine interplay in the modulation of thymopoiesis we analyzed thymocyte differentiation/maturation in non-adrenalectomized and andrenalectomized rats subjected to treatment with propranolol (0.4 mg·100 g body weight-1·day-1) for 4 days. The effects of β-adrenoceptor blockade on thymopoiesis in non-adrenalectomized rats differed not only quantitatively but also qualitatively from those in adrenalectomized rats. In adrenalectomized rats, besides a more efficient thymopoiesis [judged by a more pronounced increase in the relative proportion of the most mature single-positive TCRαβhigh thymocytes as revealed by two-way ANOVA; for CD4+CD8- F (1,20) = 10.92, P < 0.01; for CD4-CD8+ F (1,20) = 7.47, P < 0.05], a skewed thymocyte maturation towards the CD4-CD8+ phenotype, and consequently a diminished CD4+CD8-/CD4-CD8+ mature TCRαβhigh thymocyte ratio (3.41 ± 0.21 in non-adrenalectomized rats vs 2.90 ± 0.31 in adrenalectomized rats, P < 0.05) were found. Therefore, we assumed that catecholaminergic modulation of thymopoiesis exhibits a substantial degree of glucocorticoid-dependent plasticity. Given that glucocorticoids, apart from catecholamine synthesis, influence adrenoceptor expression, we also hypothesized that the lack of adrenal glucocorticoids affected not only β-adrenoceptor- but also α-adrenoceptor-mediated modulation of thymopoiesis.

[Isolation and primary culture of rat thymic epithelial cells using actinidin enzyme of kiwi fruit]

Proteolytic enzymes specially collagenase are used for degredation of extracellular matrix, cell isolation and primary cell culture. It is important to substitute a low cost and easily obtained plant or animal protease for collagenase. In the present study the enzyme actinidin which is found abundantly in kiwi fruit, was used to isolate thymic epithelial cells from rat thymus. Actinidin with different concentrations [from 1 to 10 mg/ml] and at different times [3, 4 or 5h] was used to isolate rat thymic epithelial cells. The isolated epithelial cells were cultured on collagen coated dishes in Willam's E medium. The percentage of viable isolated cells was estimated by the trypan blue test and morphology of the cells examined microscopically after staining with Papanicoloau. Actinidin with a concentration of 4 mg/ml for 3.5-4 h digested extra-cellular matrix of rat thymus and isolated thymic epithelial cell appropriately. The rate of viability of the separated cells was estimated 90-95% in all isolates. The results of this study indicated actinidin is comparable to collagenase in isolation of epithelial cells from the thymus of rat and probably other animals. Considering its simpler purification and its low cost, this enzyme is a suitable and sale substitute for collagenase which can be used for isolation of thymic epithelial cells from rat and probably other animals

Histological and genetic studies on the effect of dexamethasone on the thymus gland of adult male albino rat

Despite of Glucocorticoids have a well known immunosuppressive action, a little is known about its induction of lymphoid cell death through activation of programmed-cell death known as apoptosis. This work was undertaken with the aim of studying the histological and genetic changes in the thymus gland of albino rats following dexamethasone administration and withdrawal using different doses. Thirty-six adult male albino rats weighting 180-200 gm were used in the present study. The rats were divided into three equal groups [12 animals for each]. Group I [control], injected daily intraperitoneally [IP] with 1ml distilled water. Group H, injected daily [IP] with low dose of dexamathazone [1 gm / Kg b.w.] for seven days and group III, injected daily [IP] with high dose of dexamathazon [2 gm / Kg b.w.] for seven days. Specimens were taken one day after the 1st, 3[rd] and 7[th] injection and three animals from each group were left for recovery and sacrificed seven days after stoppage of treatment. From each specimen, a part was taken for histological, and immunohistochemical studies under light microscopy and the other part was processed for gel electrophoresis. Histological results demonstrated apoptotic changes in thymocytes after a single dose of dexamethasone, more pronounced with the high dose. Aggregation of apoptotic lymphocytes and many large macrophages engulfing apoptotic materials were seen in the cortex. The apoptotic changes were confirmed with positive reaction for Fas-ligand immune activity after a single dose of dexamethasone injection. Severe atrophy of the gland was seen more with high dose where the cortex appeared depleted from lymphocytes. Withdrawal of the drug revealed considerable degree of resolution. The lymphocytes appeared morphologically normal with dispersion of their nuclear chromatin. Our results were confirmed by the results obtained by gel electrophoresis which showed DNA ladders after one day of injection in both low and high doses and complete disappearance of ladders after seven days of medication and in recovered animals. From this study, it was concluded that dexamethasone induced apoptotic changes in thymocytes early after a short period of adminestratione and these changes were timed and dose-dependant with recovery periods proportional to the dose

Fetal Central Nervous System and Thymic Alterations Following Cyclophosphamide Treatment of Pregnant Mice / Alteraciones del Sistema Nervioso Central Fetal y Tunicas Posterior al Tratamiento con Ciclofosfamida en Ratas Preñadas

The present study assessed central nervous system (CNS) and immune system changes in murine fetuses after cyclophosphamide (CP) exposure during intrauterine life. A single CP dose of 0, 10, or 20mg/kg body weight was administered by intraperitoneal inj ection to pregnant mice (20/group) on day 11 of gestation (GD 11) and fetuses were evaluated on day 19 of gestation (GD 19). Fetuses were examined for external changes, and then the brains and thymuses were removed for further evaluations of histological changes, protein content, apoptotic cell count, DNA fragmentation, and in vitro cell proliferation using 1 fetus/litter for each assessment. Brains and thymuses from CP-exposed fetuses were smaller in size and distorted in overall shape compared to those from the control group. Estimated mean protein content (mg/mL) of brains was decreased in the CP-exposed groups. In both brain cells and thymocytes there was an increase in mean apoptotic cell counts and in mean percent DNA fragmentation in the exposed groups. The in vitro cell proliferation assays conducted with cells from exposed fetuses exhibited a mean decrease in the number of both brain cells and thymocytes generated. These findings indicate that maternal CP treatment on GD 11 in mice results in marked fetal toxicity characterized by reduced live litter size, fetal body weights as well as brain and thymic weights and malformations which are accompanied by changes in brain protein content, brain and thymic apoptosis, DNA fragmentation and in vitro cell proliferation at term.

El presente estudio evaluó los cambios en el sistema nervioso e inmunológico en fetos de roedores, luego de exposición a ciclofosfamida (CF) durante la vida intrauterina. Una dosis única de CF de 0, 10, y 20 mg/kg de peso se administró por medio de inyección intraperitoneal en ratas preñadas (grupo de 20) en el día 11 de gestación (DG11) y luego los fetos se evaluaron en el día 19 de gestación (DG19). Fueron examinados los cambios externos de los fetos, y los cerebros y timos se extrajeron para evaluar los cambios histológicos, contenido de proteínas, conteo de células apoptóticas, fragmentación de DNA y proliferación de células in vitro, usando 1 feto por carnada para cada evaluación. Los cerebros y timos de fetos expuestos a CF eran pequeños y completamente deformados , comparado con los del grupo control. La estimación del contenido proteico (mg/mL) de los cerebros estuvo disminuida en los grupos expuestos a CF. En las células del cerebro y timocitos hubo un incremento en el promedio del conteo de células apoptóticas y el porcentaje promedio de la fragmentación de DNA en los grupos expuestos. Los ensayos de proliferación celular in vitro realizados en células de fetos expuestos, mostraron una disminución en el promedio de células cerebrales y timocitos generados. Estos hallazgos indican que el tratamiento materno en el DG11 con CF en ratones significa una marcada toxicidad fetal caracterizada por un reducido tamaño de los nacidos vivos de la carnada, reducidos pesos fetal, cerebral y del timo y malformaciones, las cuales son acompañadas por cambios en el contenido proteico cerebral, apoptosis de células cerebrales y del timo, fragmentación del DNA y proliferación celular in vitro al término.

Estudio comparativo entre dos fuentes alimentarias aportadoras de ácidos grasos poliinsaturados n-3 y su efecto sobre el timo y el perfil lipídico de ratas / Comparative study between two different sources of n-3 poliunsaturated fatty acids and it effect on thymus and lipid profile in rats

En este trabajo se estudia el efecto que diferentes dietas de recuperación enriquecidas en ácidos grasos poliinsaturados n-3 (AGPI n-3) producen sobre el timo y el perfil lipídico sérico. Ratas Wistar con desnutrición proteica severa al destete (grupo D) fueron divididas en tres grupos que recibieron durante 10 días dieta a base de caseína al 20% suplementada con EPA+DHA (grupo Cas), dieta al 20% de proteína preparada usando una leche en polvo parcialmente descremada enriquecida en ácidos linoleico y linolénico (grupo L) y dieta a base de caseína al 20% (grupo control C). Cas y L aportan cada una 24 mg/día de AGPI n-3 siendo la relación n-6/n-3 de 8.1/1 y 7.6/1, respectivamente. Se extrajo y pesó el timo, determinándose el recuento de timocitos; se extrajo sangre midiéndose en suero: colesterol, triglicéridos, HDL y LDL-colesterol y los ácidos: mirístico, palmítico, esteárico, oleico, linoleico, linolénico, araquidónico, EPA y DHA. La información se analizó aplicando test de Anova. El recuento de timocitos de Cas (44.48±8.20) y L (56.45±14.72) fue superior (p<0.01) al de los grupos D (1.80±0.70) y C (23.70±4.04). L presentó concentraciones séricas de colesterol, HDL y LDLcolesterol menores (p<0.01) y triglicéridos mayores (p<0.05) que Cas, siendo EPA (p<0.05) y DHA (p<0.01) superiores en Cas. A igual aporte de AGPI n-3, ambas dietas lograron revertir la atrofia tímica presentando un efecto hipolipemiante diferente condicionado a las fuentes de AGPI n-3 utilizadas.

In the present paper we analyzed the effect caused by different recovery diets enriched with n-3 polyunsaturated fatty acids (PUFA n-3) on thymus and serum lipid pattern. Severe depleted weanling Wistar rats (D) were divided in three groups that received during 10 days a 20% casein diet supplemented with EPA+DHA (group Cas), a 20% protein milk diet prepared using a commercial reduced-fat product enriched with linolenic and linoleic acids (group L) and a 20% casein diet as control group C. Cas and L gave each other 24 mg/day of PUFA n-3 being the ratio n-6/n-3 8.1/ 1 and 7.6/1, respectively. Thymus was removed and weighted and cell number were determined; blood was recollected and Total cholesterol, triacylglycerol, HDL and LDL-cholesterol fractions and myristic, palmitic, stearic, oleic, linoleic, linolenic, araquidonic, EPA and DHA fatty acid concentrations were measured in serum. Statistical analysis was performed using Anova test. Cell number were higher (p<0.01) in Cas (44.48±8.20) and in L (56.45±14.72) when compared to group D (1.80±0.70) and group C (23.70±4.04). L presented lower values of cholesterol, HDL and LDL-cholesterol (p<0.01) and higher values of triacylglycerol (p<0.05) when compared to Cas, being EPA (p<0.05) and DHA (p<0.01) higher in Cas. Being PUFA n-3 contribution the same in Cas and L, both diets were able to reverse the thymic athropy presenting a different hipolipemic behavior due to the different sources of PUFA n-3 used in the diets.

Free radical scavenging and metal chelation by Tinospora cordifolia, a possible role in radioprotection.

Aqueous extract of T. cordifolia inhibited Fenton (FeSO4) reaction and radiation mediated 2-deoxyribose degradation in a dose dependent fashion with an IC50 value of 700 microg/ml for both Fenton and radiation mediated 2-DR degradation. Similarly, it showed a moderate but dose dependent inhibition of chemically generated superoxide anion at 500 microg/ml concentration and above with an IC50 value of 2000 microg/ml. Aqueous extract inhibited the formation of Fe2+-bipiridyl complex and formation of comet tail by chelating Fe2+ ions in a dose dependent manner with an IC50 value of 150 microg/ml for Fe2+-bipirydyl formation and maximally 200 microg/ml for comet tail formation, respectively. The extract inhibited ferrous sulphate mediated lipid peroxidation in a dose-dependent manner with an IC50 value of 1300 microg/ml and maximally (70%) at 2000 microg/ml. The results reveal that the direct and indirect antioxidant actions of T. cordifolia probably act in corroboration to manifest the overall radioprotective effects.

Thymic structural changes in relation to seasonal cycle and testosterone administration in wall lizard Hemidactylus flaviviridis (Ruppell).

Light microscopic and ultrastructural studies of thymus in wall lizard showed remarkable season dependent structural changes. In winter, the thymus was involuted and its cortico-medullary differentiation was not distinct. Thymocytes were sparsely distributed. The epithelial cells exhibited atrophic features such as an appreciable decrease in the nuclear-cytoplasmic ratio and accordingly reduction in cell organelles. The reconstruction of thymus commenced during spring and it became fully developed with marked delineation of cortico-medullary regions during summer. The thymus was then densely populated with thymocytes and epithelial cells showed voluminous cytoplasm having numerous cell organelles. The thymus regression started again by the beginning of autumn. The results suggest that the thymic development in wall lizard have inverse relationship with the androgen level, as the testicular steroidogenic activity was seen maximum during winter and least in summer. This assumption gets support by castration and testosterone replacement experiments. Castration of lizards during winter resulted in profound development of thymus with an appreciable increase in thymocytes mainly in the cortex region . The cortex became delineated from the medulla. Following testosterone treatment, the thymus underwent regression and was comparable to testis-intact lizard's thymus during winter season. After withdrawal of testosterone treatment, the thymus exhibited dense lymphoid and thymocyte population with a demarcation of cortico-medullary regions and sub-cortical region was regenerated.

Efecto del Aloe Barbadensis en la involución tímica del ratón balb/c / Effect of Aloe Barbadensis on the thymus gland involution of balb/c mice

Ratones Balb/c recién destetados recibieron por vía subcutánea 300 µg de extracto acuoso inyectable de Aloe barbadensis Miller o vera Linné durante 97 d consecutivos, con el objetivo de corroborar la aparición o no de cambios estructurales en el timo producidos por el medicamento, los que pudieran alterar incluso la involución normal de éstos. Los resultados de los exámenes histológicos fueron comparados con los exámenes homólogos de ratones de un grupo control sin tratamiento y los otros tratados con inyecciones de solución de cloruro de sodio al 0,9 porciento. La mayoría de los timos de los ratones tratados con Aloe b mostraron gran proliferación de linfocitos T a nivel de la corteza tímica, lo que retrasó la infiltración grasa de la involución a ese nivel. La infiltración sí estuvo presente en los timos de los otros grupos. Al aplicar la técnica X2 para comparar la presencia o no de proliferación linfocitaria resultó haber diferencias significativas (a : 0,05) entre el grupo tratado con Aloe b y los otros dos que evolucionaron normalmente

Effect of superoxide dismutase from bovine erithrocytes on different activity parameters in Ajuvant-Induced arthritis

Background. The purpose of this work was to evaluate the effect of superoxide dismutase (SOD) on primary swelling, lipoperoxidation, body thymus, and spleen weight in the adjuvants-induced arthritis (AIA) model in rats. Methods. Orally and intraperitoneally administered SOD (100 U/kg) from bovine erythrocytes, as well as naproxen (40 mg/kg) and dexamethasone (25 mg/kg), were evaluated againts placebo. Results. Primary edema was not decreased by SOD; in contrast, naproxen and dexamethasone showed good anti-inflammatory activity. Lipoperoxidation increased 1.8, 2.5, and 2.8 times with intraperitoneal SOD, naproxen, and dexamethasone administration, respectively, while oral SOD decreased lipoperoxidation levels to approximately one-half of that found in the control group. Body weight increased with SOD but decreased with dexamethasone. Naproxen did not change the animal weight. Thymus weight remained unchanged with SOD and naproxen, while it decreased with dezamethasone. Splee weight remained the same wih SOD, but increased with naproxen and decreased with dezamethasone. No side of gastrointestinal hemorrhage, and 50 percent of the rats in the dexamethasone group, of pulmonary infection. Conclusions. In conclusion, SOD showed no anti-inflammatory activity but decreased lipoperoxidation when administered orally. No deleterious effects in primary and secondary immunologic organs were observed with this agent

Efecto de los acidos grasos poliinsaturados n-3 PUFA sobre el timo de ratas con deplecion proteica severa / Effect of n-3 PUFA plyunsatured fatty acids on the thymus of rats submetted to severe protein depletion

Se estudia el efecto de la malnutrición proteica severa y la posterior recuperación nutricional sin y con el agregado de (n-3) PUFA, sobre el timo de ratas en período de crecimiento activo. Se determina recuento celular, población T total y actividad de adenosina deaminasa (ADA) y purina nucleósido fosforilasa (PNP). La deprivación proteica several al destete provova un frenado en la proliferación y maduración celular del timo junto con el aumento de la actividad de las enzimas ADA y PNP. La administración de la dieta de caseína al 20 por ciento durante 9 días, sólo fue suficiente para revertir el efecto observado sobre la actividad de las enzimas estudiadas. La suplementación con 24mg/d de n-3 PUFA permite restablecer la proliferación y la maduración celular tímica.

Alteraçöes metabólicas e funcionais em células e órgäos do sistema imunológico de ratos induzidas pela administraçäo intragástrica do óleo de peixe / Metabolic and functional changes in cells and organs of immune system of rats due to the fish oil administrated by gavage

O consumo de cápsulas de óleo de peixe (OP) por humanos visa a atenuaçäo dos sintomas e prevençäo de várias patologias. As alteraçöes metabólicas e funcionais em células e órgäos do sistema imunológico causadas pelo OP pela administraçäo intragástrica (AIG) foram avaliadas. Ratos recém-desmamados (50-70 g) foram submetidos a AIG diária com óleo de peixe, óleo de soja ou manteiga de cacau (0,4 por cento do peso), por 28 dias. Os dados da AIG do OP foram também comparados com os da dieta enriquecida com OP. Foram avaliados: aumento de permeabilidade vascular (reaçäo anafilática), funcionalidade de macrófagos (produçäo de 'H IND. 2O IND. 2', 'O IND. 2' e fagocitose), proliferaçäo de linfócitos, a atividade máxima das enzimas: hexoquinase, glicose-6-fosfato desidrogenase, citrato sintase (metabolismo de glicose), catalase, glutationa peroxidase e superóxido dismutase (antioxidantes) no baço, linfonodo mesentérico e timo. A concentraçäo de TBARs nos mesmos órgäos e no plasma e a capacidade antioxidante do plasma foram também determinadas

Hormonas tímicas como mediadoras de la integración inmunogonadotropa / Thymic hormones as mediators of the inmunogonadotroph integration

Existe significativa evidencia sobre la existencia de un eje timo-hipofiso-gonadal. En razón de que estudios previos de los autores habían demostrado que la Hormona Homeostática Tímica, un dímero de histonas H2A y H2B, posee múltiples efectos in vivo sobre la secreción de hormonas hipofisarias, resultó de interés evaluar el efecto in vitro de distintas preparaciones tímicas y proteínas nucleares relacionadas, sobre la liberación de prolactina (Prl), hormona foliculoestimulante (FSH) y hormona luteinizante (LH). Células hipofisarias frescas de ratas hembras se dispersaron con colagenasa y se empaquetaron en una columna de Biogel P-2 mantenida a 37oC. Las células se perifundieron continuamente con medios EBSS, o,5 por ciento de BSA, 1 por ciento de ácido ascórbico y 50 IU de aprotinina/ml (medio de perifusión, MP). Las sustancias a ser testeadas (estímulos) se disolvieron en MP, perifundiéndose en un volumen de 1,5 ml por estímulo a través del circuito de perifusión, al final del cual se recogieron fracciones de 1 ml. Las hormonas liberadas se dosaron por radioinmunoensayo. La viabilidad de las células dispersas osciló entre 84 y 96 porciento. Distintas diluciones de extractos de eminencia media de rata generaron, para cada hormona, una respuesta estimulatoria dosis-dependiente. En general, tanto las preparaciones de histona H2A como las de nucleohistona (ambas a una concentración de 500 µg/ml) indujeron picos secretorios significativos de LH, FSH y Prl, siendo los más elevados los correspondientes a Prl. Asimismo, la hormona tímica timulina y sobrenadantes provenientes de cultivo de células epiteliales tímicas de rata y ratón, pero no la timosina fracción ÷ o el péptido tímico MB-35, resultaron estimulatorios. Los resultados del presente trabajo sugieren que ciertos productos tímicos podrían participar en la integración inmuno-gonadotropa, actuando como señales hipofisotropas

Radioprotection of chick thymus by vitamin E.

One day and 7 days old male white leghorn chicks were administered vitamin E prior to their exposure to sublethal dose (2.25 Gy) of gamma radiation from 60C source. The results show that vitamin E helps in faster recovery of damage in chick thymus caused by irradiation.

Spleen and thymus histology and proliferative response of splenic cells in rats fed raw and cooked Phaseolus vulgaris beans

Histological studies of the spleen and thymus of rats fed raw black beans (Phaseolus vulgaris) show an atrophy of both lymphoid organs. Decrease in relative thymus weight was most marked. All histological organization of this organ appeared altered. An evident decrease in cell number was also observed in both organs. Proliferative response of splenic cells stimulated in vitro with Concanavalin A was increased as compared to that from animals fed the control diet. It is likely that histological changes observed in the spleen and the thymus are due mainly to a protein caloric deficiency, although the possibility that toxic factors present in the raw diet have an effect on the immune system of the rat can not be overruled

Pathogenesis of wasting disease after cyclophosphamide treatment of neonatal mice.

Cyclophosphamide is a potent immunosuppressive agent and is being widely used in organ transplantation. The effects of this anti-rejection drug on lymphoid organs are poorly understood. Newborn Swiss mice injected with various doses of cyclophosphamide suffered from wasting disease at 4 weeks post treatment. The incidence of wasting disease was dose dependent. Haematological picture of the wasting animals revealed leukocytosis of variable degree. Lymphocyte/granulocyte ratio was not inhibited. The cyclophosphamide treatment caused shrinkage of lymphoid organs. Bone marrow showed degeneration of haematopoietic cells. The failure to sustain lymphopoiesis by the potential lymphoid sites following cyclophosphamide treatment and the associated immunological insufficiency resulted in the fatal wasting disease.