M. A. Gómez

Identification of Somatomammotroph Cells in Lactating Goats (Capra hircus) by Fluorescence and Immunogold Techniques

The occurrence and ultrastructural morphology of somatomammotroph cells, in the anterior pituitary tissue of the goat, is studied using fluorescence microscopic double staining and two methods of double immunogold staining combined with electron microscopy. Under the fluorescence microscope numerous monohormonal cells, either mammotroph cells (prolactin, PRL, cells) or somatotroph cells (growth hormone, GH, cells) are observed, but cells containing both hormones (somatomammotroph or SMT cells) are scarce. SMT cells do not differ ultrastructurally from monohormonal cells, and the cytoplasm contains two populations of granules, each reactive only for one of the antisera, either antisheep GH or antisheep PRL.

Pathological changes of spontaneous dual infection of tuberculosis and paratuberculosis in goats.

Abstract Dual spontaneous infection of tuberculosis and paratuberculosis was studied in 23 goats from different herds in the region of Murcia, Spain. Animals were selected because of positive reaction to the CTID test, and showed clinical signs of Mycobacterium bovis and M. paratuberculosis following anatomo-pathological procedures, which were confirmed in the case of M. bovis by bacteriological analysis. Tuberculosis was found in different stages of infection: a primary complex in two animals, early generalization in six animals, organic-chronic tuberculosis in 10 animals and late generalization in five animals. Paratuberculosis lesions were observed in the intestine of 22 animals, in the mesenteric lymph nodes of 13 animals, and in the liver of 17 animals. Lesions of both diseases were found in the intestines of three animals, in the mesenteric lymph nodes of six animals, and in the liver of seven animals.

POSTNATAL DEVELOPMENT OF LYMPHOCYTE SUBPOPULATIONS IN THE INTESTINAL MUCOSA IN GOAT

The incidence and location of CD2+, CD4+, CD8+ and gamma/delta T-lymphocytes and B-lymphocytes were studied in the intestinal mucosa in goats of one week, one month, three months and seven months old, using monoclonal antibodies and immunohistochemical methods. At all ages CD2+ lymphocytes were the major subpopulation in the intestinal mucosa, more numerous in the small than in the large intestine and in the villi than in the crypt region. In one week-old animals most of CD2+ lymphocytes were scattered in the lamina propria and the number of lymphocytes that expressed CD4 was less than those that expressed CD8, resulting in a CD4/CD8 ratio less than 1. CD2+ lymphocytes increased markedly until one month old, with a higher increase of CD4+ subpopulation than CD8+ with an inversion of the CD4/CD8 ratio. CD4+ lymphocytes were localised in the lamina propria forming clusters, whereas CD8+ lymphocytes were scattered peripherally under the epithelium and in older animals from three month old, CD8+ lymphocytes were also abundant between epithelial cells. The gamma/delta T-lymphocytes recognised with the mAb CACTB6A represented a minor subpopulation located between epithelial cells or in the lamina propria, no evident changes were observed with age. IgM+ cells were a minor subpopulation in all animals (never higher than 1 cell per 1500 microns-2) located in the crypt region of the lamina propria.

Immunogold Identification of Prolactin Cells of Goats in Anoestrus, Pregnancy and Milk Production: Ultrastructural Variations

Prolactin (PRL) cells of the goat adenohypophysis have been identified by the IgG-gold procedure with anti-sheep PRL serum. The secretion of these cells show differences in size and labelling in the three reproductive stages under study. Cells containing PRL can be grouped into low secretory activity cells (PRL-I) and high secretory activity cells (PRL-II) regarding their ultrastructure and functional significance. PRL-I were the most frequent cells in animals at the anoestrus stage, presenting numerous secretory granules and scarce development of the rough endoplasmic reticulum (RER) and Golgi complex (GC). At anoestrus and pregnancy stages there are frequent granule fusions, and the hormonal content partially disappears, perhaps by digestion. PRL-II cells were the most numerous at the lactating stage, presenting a moderate number of secretory granules and well-developed GC and RER. Some PRL-II cells of lactating animals exhibiting scarce granules and numerous exocytosis suggesting a high secretory activity. In both anoestrus and pregnancy stages most granules range in diameter from 450 to 750 nm, in contrast to the lactating stage in which most granules range in diameter from 150 to 450 nm.

Light and Ultrastructural Immunocytochemical Study of Prolactin Cells in Ovine Adenohypophysis

The influence of lactation and weaning on the number, distribution, and structure of mammotroph cells (PRL cells) in ewes was studied using immunocytochemical procedures for light and electron microscopy, as well as morphometric and stereological techniques. The adenohypophyseal gland of 12 ewes of the Segureña breed at different stages of milk production and weaning were analysed, while the same organ of 3 ewes in anestrus served as control. During lactation, PRL cells increased in number and decreased in size. Ultrastructurally, these cells showed a well-developed rough endoplasmic reticulum (RER) and Golgi complex (GC), and large secretory granules. These findings point to increased synthesis and secretion activities during lactation, and a decrease after weaning. One day after weaning ‘storage’ cells increased in number, and crinophagy became evident 7 days after weaning, when the first ‘inactive’ cells were seen (10% of total cells). In anestrus these last cells represented 40% of the total, and showed scarce granules, signs of inactivity, lysosomes and lipid droplets.

Immunocytochemical Light- and Electron-Microscopic Studies of Growth Hormone, Prolactin and Somatomammotroph Cells in Female Goat

We have studied the structural and ultrastructural changes that occur in growth hormone (GH), prolactin (PRL) and somatomammotroph (SMT) cells of female goats of the Murciano-Granadina breed during different physiological stages: prepuberty, anestrus, pregnancy and lactation. Serial sections were stained with double immunolabeling, alkaline phosphatase and avidin-biotin complex for light microscopy, and immunogold labeling was used for electron microscopy. These techniques allowed the identification of GH, PRL and SMT cells, which were evenly distributed throughout the whole pars distalis. PRL cells were the most frequent. Both PRL and GH cells showed morphological changes that may be related to a given physiological stage. These changes include the number of cells and the number and size of the secretory granules. SMT cells were clearly identified by having two types of monohormonal secretory granule showing single labeling, in spite of their similar ultrastructural characteristics to the other adenohypophysary cells. They are found in low percentages (0.6%). We postulate that cell aggregates which look like SMT syncytia may be artifacts caused by interdigitation of PRL and GH cells, and that cells which are normally taken to be SMT cells are not an interconversion stage between monohormonal cells.

Osteoblastic osteosarcoma in a fattening pig

Electrophysiology 15, 2068-2073 RISHNIW, M., TOBIAS, A. H. & SLINKER, B. K. (1996) Characterisation of chronotropic and dysrhythmogenic effects of atropine in dogs with bradycardia. American Journal of Veterinary Research 57, 337-341 SAITO, D., MATSUBARA, K., YAMANARI, H., OBAYASHI, N., UCHIDA, S., MAEKAWA, K., SATO, T., MITZUO, K., KOBAYASHI, H. & HARAOKA, S. (1993a) Effects of oral theophylline in sick sinus syndrome. Journal of the American College of Cardiology 21, 1199-1204 SAITO, D., YAMANARI, H., MATSUBARA, K., MAEKAWA, K., MIZUO, K., SATO, T., KOBAYASHI, H., MORITA, H. & HARAKOA, S. (1993b) Intravenous injection of adenosine triphosphate for assessing sinus node dysfunction in patients with sick sinus syndrome. Arzneimittelforschung 43, 1313-1316 SGARBOSSA, E. B., PINSKI, S. L., TROHMAN, R. G., CASTLE, L. W. & MALONEY, J. D. (1994) Single-chamber ventricular pacing is not associated with worsening of heart failure in sick sinus syndrome. American Journal of Cardiology 73,693-697 SISSON, D. D. (1989) Bradyarrhythmias and cardiac pacing. In Current Veterinary Therapy X. Ed R. W. Kirk. Philadelphia, W. B. Saunders. pp 286294 SISSON, D. D., THOMAS, W. P., WOODFIELD, J., PION, P. D., LUETHY, M. & DELELLIS, L. A. (1991) Permanent transvenous pacemaker implantation in forty dogs. Journal of Veterinary Internal Medicine 5, 322-331 SMITH, F. W. K., Jr & HADLOCK, D. J. (1995) Electrocardiography. In Manual of Canine and Feline Cardiology. 2nd edn. Eds M. S. Miller, L. P. Tilley. Philadelphia, W. B. Saunders. pp 47-74 SNEDDON, J. F. & CAMM, A. J. (1992) Sinus node disease: current concepts in diagnosis and therapy. Drugs 44,728-737 TILLEY, L. P. (1992) Sick sinus syndrome. In Essentials of Canine and Feline Electrocardiography. 3rd edn. Ed L. P. Tilley. Philadelphia, Lea & Febiger. pp 184-187 ZIPES, D. P. (1997) Specific arrhythmias: diagnosis and treatment. In Heart Disease: a Textbook of Cardiovascular Medicine. 5th edn. Ed E. Braunwald. Philadelphia, W. B. Saunders. pp 648-649

Light and ultrastructural immunocytochemical study of somatotropic cells (GH cells) in ovine adenohypophysis: lactation and weaning influences.

The influence of lactation period and weaning on the distribution, number, and structure of somatotropic cells (GH cells) in ewes was studied using immunocytochemical procedures for light and electron microscopy, as well as morphometric and stereological techniques. The adenohypophyseal gland of 12 ewes of the Segureña breed in different stages of milk production and weaning was studied, while three ewes in anoestrus served as controls. The size of secretory granules was heterogeneous in all stages, suggesting that this characteristic is not related to functional activity. During lactation and weaning the size of GH cells decreased, while the number of ‘synthesis cells’ increased. The rough endoplasmic reticulum and Golgi complex appeared more developed and small secretory granules showed lower gold particle labelling. These data suggest that GH cells are more active during lactation, particularly during late lactation.

Postnatal Development of Lymphocyte Subpopulations in the Intestinal Lymph Nodes in Goats

The incidence and location of CD2+, CD4+, CD8+ and γ/δ T lymphocytes and IgM+ B lymphocytes were studied in the intestinal lymph nodes in 1‐week, 1‐month, 3‐month and 7‐month‐old goats, using monoclonal antibodies and immuno‐histochemical methods. The cortical area of the intestinal lymph nodes in 1‐week‐old animals contains only primary follicles occupied by IgM+ B lymphocytes and some CD2+CD4+ T lymphocytes. In goats older than 1 month, secondary follicles, that increased in number and size with age, were observed; the light zone of the germinal centre was occupied by IgM+ lymphocytes and some CD2+ and CD4+ T lymphocytes. In the other compartments of the lymph nodes, B lymphocytes were scarce, their number increasing with age in the medulla and diminishing in the paracortex. The numerous CD2+ T lymphocytes in the interfollicular area increased in number in the paracortical area of the 7‐month‐old goats, simultaneously with an increase in the MHC II+ dendritic cells and the CD4/CD8 ratio, which was greater than 1. The γ/δ T lymphocytes represented a minor subpopulation scattered through the lymph nodes.

Structure and ultrastructure of adrenocorticotropic hormone cells in goats in anoestrus, gestation and milk production.

The structural and ultrastructural characteristics of adrenocorticotropic hormone cells in adult female goats in anoestrus, gestation and milk production were studied with an immunohistochemical method (peroxidase-antiperoxidase). Only one cellular type has been identified and is characterized by numerous secretory granules of different electron density and an average diameter of 275 nm. During pregnancy these cells increase in number and size, and there is a frequent presence of vacuoles. During lactation the number of size of the cells decreases but without reaching the state observed in anoestrus and the involution of the cytoplasmic vacuolizations which appear in pregnancy.