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Biomedical subjects

S A Bencosme

Publications and source records attributed to S A Bencosme.

At least 19 recordsLinked to original sources
PubMed1981

Reflex hypoglycemia initiated by insulin.

The injection of a bolus of insulin (40 millimicrons) in the coeliac trunk in anesthetized rabbits elicits an immediate rapid rise of arterial IRI. Inferior vena cava and jugular glucose levels drop precipitously 2 min after insulin injection, increasing the A-V glucose difference. The same amount of insulin injected via the coeliac trunk in abdominal-vagotomized rabbits, failed to induce any significant changes in venous glucose concentration and A-V glucose, although there was a similar rise of IRI concentration in arterial plasma. Electrical stimulation of the central stump of the abdominal vagi does not alter the IRI levels in arterial plasma, however, arterial blood glucose increases suddenly, venous blood glucose drops in the first 2 min of stimulation and the A-V glucose difference increases; there are no significant changes in blood flow, arterial pressure and oxygen saturation in cephalic circulation. These data suggest that small amounts of insulin injected or secreted in a zone irrigated by the coeliac trunk, trigger a hypoglycemic reflex. Evidence is provided to suggest that this is by causing a rapid increase in glucose both by the brain and leg muscle mass.

Animals↗
PubMed1978

Intracellular pancreatic B cell serotonin and the dynamics of insulin release.

The role of intracellular pancreatic B cell serotonin in the dynamics of insulin release was investigated in an in situ perfused rat pancreas preparation. Animals were pretreated with 5-hydroxytryptophan (5-HTP) to increase the intracellular levels of serotonin (5-HT) as shown by fluorescence histochemistry. Despite a clear induction of intracellular 5-HT fluorescence in pancreatic islets neither the pattern nor the total amount of insulin released were significantly modified after perfusion with either glucose or tolbutamide. However, the L-amino acid decarboxylase inhibitor, RO 4--4602, significantly decreased both phases of glucose-mediated insulin release in normal animals as well as in those receiving 5-HTP.

5-Hydroxytryptophan↗
PubMed1978

Atrial specific granules of the rat heart: light microscopic staining and histochemical reactions.

An investigation was carried out to determine general staining and histochemical properties of rat atrial specific granules. It was found that these granules may be demonstrated using aldehyde fuchsin after pretreatments which involve oxidation or thiosulfation. This new way of demonstrating atrial granules is compared to other staining methods in terms of sensitivity and selectivity as well as to the nature of reactive groups that may be involved in the staining reactions. No lipid or carbohydrate were detected histochemically. Overall assessment of reactions suggests that atrial granules are a site of storage for a protein or polypeptide. Some of the tests indicate that these may contain tryptophan and sulfur-containing amino acids.

Amino Acids, Sulfur↗
PubMed1975

Selective light microscopic demonstration of the specific granulation of the rat atrial myocardium by lead-hematoxylin-tartrazine.

MacConaill's lead-hematoxylin as modified by Solcia et al. was found to be a highly selective stain for the specific granulation of atrial cardiocytes in the rat. The specific atrial granules were stained blue-black. Contrast was enhanced by counterstaining in a saturated solution of tartrazine in Cellosolve. The stain is compatible with several fixatives and may be used with paraffin or Epon-embedded material.

Animals↗
PubMed1975

Autoradiographic analysis of label distribution in mammalian atrial and ventricular cardiocytes after exposure to tritiated leucine.

Radiolabeled leucine was used as a marker for newly synthesized proteins in rat atrial and ventricular muscle. The fate of these proteins was assessed during time-course experiments using high resolution autoradiography. Special attention was paid to the labeling pattern in the central sarcoplasmic cores of atrial cardiocytes. The data obtained are compatible with the view that these cells synthesized, concentrate, and a store a product of protein nature in a fashion similar to that observed in some secretory cell types.

Animals↗
PubMed1973

Staining procedures for the endocrine cells of the upper gastrointestinal mucosa: light-electron microscopic correlation for the gastrin-producing cell.

Although histochemical, immunohistochemical, and electron microscopic methods have led to the identification of a large variety of endocrine cells in the upper gastrointestinal mucosa, no conventional light microscopic technique capable of the simultaneous identification of these cells has been reported. Such a staining method would be of considerable value to the pathologist as the malfunction of the endocrine cells of the gut, which produce numerous digestive hormones and biogenic amines, is closely related to a number of clinical conditions afflicting man. In this work, after testing three different polychrome staining methods, it has been concluded that a slightly modified Herlant's tetrachrome in tissues fixed in Zenker-formol is the procedure of choice. This method allows the distinction of several different cell types in the upper gastrointestinal mucosa of man and dog and permits the easy identification of the gastrin-producing cells on a routine basis. This identification has been confirmed in the case of two patients with gastrin cell hyperplasia, seen by both light and electron microscopy. Herlant's tetrachrome has proven valuable in the screening of human as well as experimental gastrointestinal tissues and it has been found to be very suitable for recognizing gastrin-producing cell hyperplasias. The usefulness of this method is expected to increase with the establishment of further correlations between the light and electron microscopy of the endocrine cells of the gut.

Adenocarcinoma↗