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Biomedical subjects

P Sesma

Publications and source records attributed to P Sesma.

At least 19 recordsLinked to original sources
PubMed2003

[Treatment of chronic obstructive pulmonary disease].

Chronic obstructive pulmonary disease (COPD) is a highly prevalent condition and most epidemiological studies have found that COPD prevalence, morbidity and mortality have increased over the last few years. Recent trials suggest that treatments are improving. Several studies have demonstrated the usefulness of the long-acting inhaled beta-2-agonists. Inhaled glucocorticoids, although unable to alter the progression of COPD, may reduce the frequency of acute exacerbations and health status deterioration in a limited group of patients with COPD. Likewise, these drugs may offer benefits in combination with long-acting inhaled beta-agonists. Finally, a better understanding of the molecular and cellular mechanisms involved in COPD pathogenesis should lead to effective treatments that slow or halt the course of the disease. New classes of agents such as the phosphodiesterase inhibitors are now in development.

Bronchodilator Agents↗
PubMed2002

[Chronic lead poisoning].

Epidemiologic studies have shown a steady decrease in the blood lead concentrations in populations from developed countries. This decrease is due to the promulgation of legislative measures designed to reduce sources of environmental lead exposure. As a result, during the last several years, lead poisoning has been reported with a minor frequency. We describe here three patients with chronic lead poisoning owing to chronic ingestion of water contaminated by lead pipes.

Chronic Disease↗
PubMed2001

Syncope.

Explore the source record for details and available documents.

Accidental Falls↗
PubMed2001

Immunocytochemical and ultrastructural characterization of endocrine cells in the larval stomach of the frog Rana temporaria tadpoles: a comparison with adult specimens.

According to immunostaining and ultrastructural patterns, Rana temporaria tadpole stomach displays a well-differentiated endocrine population comprising, at least, six cellular types: ECL, EC [serotonin], D [somatostatin] - all three of them abundant -, P [bombesin] - less numerous -, CCK-8 [cholecystokinin/gastrin] and A [glucagon/glicentin] - both very scarce. Larval endocrine cells are mainly located in the surface epithelium and show open or closed morphologies. Cellular diversity is similar in tadpoles and frogs, with the exception of immunoreactivity for gastrin-17, found in adults in numerous cells. Larval cells display mature ultrastructural traits, although with smaller secretory granules. The different distribution of endocrine cells, which in adults are preferentially located in the glands, probably refers to different functional requirements. However, the rich vascular plexus present in larval mucosa may be an efficient transport medium of surface hormones to-gastric targets. The enhancement in adults of endocrine population and correlative increase in hormonal secretion indicates a more active functional role, probably related to the shift from herbivorous to carnivorous habits. In summary, the tadpole gastric endocrine population, although not as numerous as that of adult frogs, displays histological traits that indicate a relevant (immunoreactive and ultrastructural properties, cellular diversity) and specific (surface location, relative abundance of open-type cells) role of local regulatory factors in amphibian larval gastric function.

Animals↗
PubMed2000

Characterization of pancreatic endocrine cells of the European common frog Rana temporaria.

To characterize the endocrine cell types of the pancreas of Rana temporaria, conventional staining, silver impregnation, and immunocytochemical methods for light and electron microscopy have been applied to paraffin, thin and semithin sections, many of them serial pairs. Quantitative data on the frequency and distribution (insular, extrainsular among the exocrine cells, or within the pancreatic ducts) of each endocrine cell type are also reported. Four distinct endocrine cell types have been identified: insulin (B) cells, which are also immunoreactive for [Met]enkephalin; glucagon/PP (A/PP) cells, also immunoreactive for GLP1; somatostatin (D) cells; and a fourth endocrine-like cell type (X cells) of unknown content and function. X cells display characteristic ultrastructure and tinctorial traits but are nonimmunoreactive for all of the 37 antisera tested. The presence of [Met]enkephalin in amphibian pancreatic endocrine cells is now reported for the first time. Almost half (44.9 +/- 7.9) of the total endocrine cell population lies outside the islets, mainly spread among the exocrine cells. Approximately 37.2 +/- 4.6% of the total endocrine cell population was immunoreactive for insulin, 48.8 +/- 6.9% was immunoreactive for glucagon/PP, and 14.0 +/- 4.9% was immunoreactive for somatostatin; 79.2 +/- 6.4% of glucagon/PP cells are found within the exocrine parenchyma, representing the majority (86.4 +/- 4.3%) of extrainsular endocrine component. On the contrary, most B cells (94.2 +/- 2.1%) are located within the islets; 30.8 +/- 12.9% of D cells are found outside the islets.

Animals↗
PubMed2000

The nervous system of the chicken proventriculus: an immunocytochemical and ultrastructural study.

The proventriculus constitutes the glandular region of the chicken stomach. This organ is innervated by two parasympathetic networks, the myenteric and submucous plexus, and here we present a systematic study of this system by immunohistochemistry and electron microscopy. All the neurons and fibres were positive for the neural markers, protein gene product 9.5 and the amidating enzymes. Immunoreactivities for the constitutive neuronal isoform of the enzyme nitric oxide synthase and the vasoactive intestinal peptide were present in neuronal bodies suggesting an intrinsic origin for the similarly immunoreactive fibres found in the proventriculus. On the other hand, immunoreactivity to gastric inhibitory peptide was only found in varicose fibres making contact with the blood vessels and the glandular epithelium, but never in the neuronal somas, suggesting that this substance may be provided by an extrinsic nervous system whose neuronal bodies are located elsewhere. Electron microscopy revealed frequent neuromuscular and neuroepithelial connections in the muscle layers, the wall of the blood vessels and the epithelium. In addition, synapsis-like structures were identified in the proximity of cells belonging to the diffuse endocrine system, providing a new example of neuroendocrine contacts. No positivity was found for antibodies against other neural substances including somatostatin, peptide histidine-isoleucine, peptide tyrosine-tyrosine, neuropeptide tyrosine, bombesin, met-enkephalin, serotonin, substance P, galanin, calcitonin gene-related peptide and S-100 protein.

Animals↗
PubMed2000

Colocalization of numerous immunoreactivities in endocrine cells of the chicken proventriculus at hatching.

The colocalization of regulatory peptide immunoreactivities in endocrine cells of the chicken proventriculus at hatching has been investigated using the avidin-biotin technique in serial sections and double immunofluorescence in the same section for light microscopy, and double immunogold staining for electron microscopy. In addition to the eight immunoreactivities previously described in this organ, cells immunoreactive for peptide histidine isoleucine (PHI), peptide gene product 9.5 (PGP), and the amidating enzyme, peptidylglycine alpha-amidating monooxygenase (PAM) were observed. All the cells immunoreactive to glucagon were also immunostained by the PHI antiserum. In addition, all the glucagon-like peptide 1, avian pancreatic polypeptide, and some of the neurotensin-like cells costored also glucagon- and PHI-immunoreactive substances. PGP- and PAM-immunoreactivities were also found in the glucagon-positive cells. A small proportion of the somatostatin-containing cells were positive for PHI but not for other regulatory peptides. These results could suggest either the existence of a very complex regulatory system or that the endocrine system of the newborn chickens is not yet fully developed.

Animals↗
PubMed1999

Light and electron microscopic study of the hindgut of the ant (Formica nigricans, hymenoptera): I. Structure of the ileum.

The study of the ileum of the ant Formica nigricans by light and electron microscopy revealed the existence of three differentiated regions: proximal, middle, and distal ileum. The middle region constitutes most of the length of the organ. Its wall is made up by a folded simple epithelium lined by a cuticle, which is surrounded by an inner circular muscle layer and various external longitudinal muscle fibers adjacent to the hemolymph. A subepithelial space is present between the epithelium and the circular muscle layer. Epithelial cells show extensive infoldings of the apical, and to a lesser extent the basolateral plasma membrane. Apical infoldings are characterized by the presence of 10-nm particles (portasomes) covering the cytoplasmic side of the membrane. Mitochondria are abundant throughout the cytoplasm, although they mainly are present underneath the apical infoldings. Lateral borders of epithelial cells display an apical junctional complex, mainly constituted by a long and convoluted pleated septate junction. These features support the view that epithelial cells in the middle ileum are specialized in ion solutes and water transport. The proximal ileum connects with the ampulla into which the Malpighian tubules drain. As opposed to the middle ileum, epithelial cells of the proximal ileum show less developed basolateral infoldings, and the apical plasma membrane is devoid of portasomes and only occasionally invaginates. These features suggest that the proximal ileum plays no relevant role in ion and water transport. The distal ileum penetrates into the rectal sac, forming a valve-like structure; this region presumably controls the amount of urine reaching the rectum.

Animals↗
PubMed1999

Light and electron microscopic study of the hindgut of the ant (Formica nigricans, hymenoptera): II. Structure of the rectum.

The rectum of the ant Formica nigricans is composed of six ovoid rectal papillae inserted into a rectal pouch. The wall of the rectal pouch is made up of a flat epithelium of simple rectal cells lined by cuticle, and surrounded by a circular muscle layer. Each rectal papilla is comprised by a simple columnar epithelium of principal cells facing the lumen, and a simple cuboid epithelium of secondary cells towards the hemolymph; a group of 20-25 slender junctional cells lies laterally between both epithelia enclosing an intrapapillar sinus. The muscle layer of the rectal wall also surrounds the base of the papillae. Principal cells do not exhibit extensive infoldings at the apical and basal plasma membranes. Lateral membranes, in contrast, develop highly folded mitochondria-scalariform junction complexes enclosing very narrow intercellular canaliculi between adjacent cells. These canaliculi open to wider intercellular sinuses that ultimately drain into the intrapapillar sinus at the sites of entry of tracheal cells. The lateral plasma membranes do not link to the apical or basal plasma membrane, thus originating a syncytium throughout the principal cells. The apical plasma membrane of secondary cells shows invaginations in relation with an apical tubulovacuolar system, bearing portasomes to the cytoplasmic side of the membrane. Secondary cells unite by convoluted septate junctions, and basolateral infoldings are also developed. These ultrastructural traits, some of them different from those found in other insects, are discussed and examined in relation to their role in water and solute absorption. A route for rectal transport in F. nigricans is proposed.

Animals↗