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Biomedical subjects

J M Affanni

Publications and source records attributed to J M Affanni.

At least 19 recordsLinked to original sources
PubMed1997

Purification and partial structural characterization of a fatty acid-binding protein from the liver of the South American armadillo Chaetophractus villosus.

The fatty acid-binding protein (FABP) from armadillo liver was purified to homogeneity by a procedure involving gel filtration and two anion exchange chromatography steps. The purified protein proved to have a pI between 5.0 and 5.2 and migrated by sodium dodecyl sulfate-polyacrilamyde gel electrophoresis as a single entity of approximately 14 kDa. The armadillo FABP cross-reacted with antiserum against rat liver FABP but not against rat intestinal FABP. The same as other members of the family, it has a blocked N-terminus. Amino acid sequencing of peptides obtained by cyanogen bromide cleavage and in-gel tryptic digestion shows that the armadillo, despite being one of the less evolved mammals, has a liver FABP of the same type as that of highly evolved mammals.

Amino Acid Sequence↗
PubMed1996

Highly sensitive method for the determination of melatonin by normal-phase high-performance liquid chromatography with fluorometric detection.

In the present study a new chromatographic method was developed to quantify melatonin in rat pineal that can be extended to other tissues. Melatonin was extracted from an acid homogenate with ethyl acetate to avoid amine interference. HPLC was performed with silica normal-phase column and fluorescence detection. This method is sensitive enough for detecting melatonin in a single pineal gland with a detection limit of 3 pg/mg tissue.

Acetates↗
PubMed1996

Identification of immunoreactive mammalian gonadotropin-releasing hormone in the brain of metamorphic larvae of Bufo arenarum Hensel (Amphibia: Anura).

Gonadotropin-releasing hormone (GnRH) immunoreactivity in brain extracts of Bufo arenarum tadpoles were investigated by high-performance liquid chromatography, followed by radioimmunoassay analysis using two different antisera raised against different GnRH variants. Only one immunoreactive peak was identified, eluting in the same position as synthetic mammalian GnRH. This result was further confirmed by serial dilution studies using more specific mammalian GnRH antisera. Our results suggest that mammalian GnRH is most likely an endogenous peptide in the brain of the developing larvae and froglets of Bufo arenarum and quite likely it is the only GnRH variant present during those development stages. The distribution and density of cell bodies and fibers were analysed by immunocytochemical procedures. Immunoreactive cell bodies appeared in the olfactory epithelium and across the olfactory nerve at late prometamorphic larval stages. Near the metamorphic climax and in froglets, perikarya and fibers were detected in basal forebrain, preoptic and hypothalamic areas. No immunoreaction was observed at midbrain, hindbrain and spinal cord levels. This study suggests that mammalian GnRH is most likely an endogenous peptide and is probably the only GnRH variant in the brain of the developing larvae and froglets of Bufo arenarum.

Animals↗
PubMed1996

Standardization of fixation, processing and staining methods for the central nervous system of vertebrates.

This paper reports the standardization of methods used for processing and embedding various vertebrate brains of different size in paraffin. Other technical details developed for avoiding frequent difficulties arising during laboratory routine are also reported. Some modifications of the Nissl and Klüver-Barrera staining methods are proposed. These modifications include: 1) a Nissl stain solution with a rapid and efficient action with easier differentiation; 2) the use of a cheap microwave oven for the Klüver-Barrera stain. These procedures have the advantage of permitting Nissl and Klüver-Barrera staining of nervous tissue in about five and fifteen minutes respectively. The proposed procedures have been tested in brains obtained from fish, amphibians, reptiles and mammals of different body sizes. They are the result of our long experience in preparing slides for comparative studies. Serial sections of excellent quality were regularly obtained in all the specimens studied. These standardized methods, being simple and quick, are recommended for routine use in neurobiological laboratories.

Animals↗
PubMed1995

Decrease of body temperature in armadillos experimentally covered by soil.

The armadillo Chaetophractus villosus does not stop breathing when experimentally covered with soil. Under that condition, there is a gradual but considerable drop in deep rectal temperature (TB): after 90 minutes, mean +/- SD = 1.7 +/- 0.4 degrees C (n = 8). As soon as the soil is removed and the animal breathes open air, TB gradually increases.

Adaptation, Physiological↗
PubMed1995

Bradycardia in armadillos experimentally covered with soil.

Chaetophractus villosus is able to maintain efficient respiratory movements when its nostrils are experimentally covered with soil. Under these conditions, a progressive bradycardia develops. It would depend on hypothermia and asphyxia.

Adaptation, Physiological↗
PubMed1995

New and peculiar cytoplasmic membranous bodies in the acinar cells of the harderian gland of the armadillo Chaetophractus villosus.

A new and peculiar morphological feature in acinar cells of the Harderian gland of the South American armadillo Chaetophractus villosus (Mammalia, Dasipodidae) is reported. The gland of adult males and females was studied at macroscopic, microscopic and electron microscopic levels. The gland is the largest structure in the bony orbit. It is located in its medial (nasal) and basal side. It shows a tubuloalveolar structure characterized by large alveoli with a single layer of columnar or cuboidal cells. Myoepithelial cells are located between the secretory ones and the basement membrane. The peculiar morphological feature consists of large intracellular membranous bodies located in the supranuclear cytoplasmic region. They are seen in every acinar cell of males and females. Their size is prominent being almost as large as the nucleus. Only one body is observed in each cell. The structure of the bodies displays an outstanding geometrical pattern which differs completely from other membranous structures described in other species.

Animals↗
PubMed1987

On the presence of a peculiar alpha rhythm in the olfactory tubercle of waking armadillos.

A very regular 8-12 rhythm was found in the olfactory tubercle of the armadillo Chaetophractus villosus. The rhythm was observed during wakefulness. Considerable sinusoidal activity was also observed not only during wakefulness, but during synchronized (slow) and desynchronized (paradoxical) sleep. The significance of this novel rhythm is discussed together with considerations that establish an important difference between it and the other 'alpha rhythms' known.

Alpha Rhythm↗
PubMed1987

Absence of apnea in armadillos covered by soil.

The armadillo Chaetophractus villosus shows a remarkable respiratory adaptation when the nostrils are completely covered by soil: it is able to maintain efficient respiratory movements with the corresponding filling of the lungs, thanks to a mechanism that allows it to use the air filling the space between the soil particles, without invasion of the nasal cavities by those particles.

Anesthesia↗
PubMed1986

A novel receptive area of key importance for the onset of diving responses in the duck.

We have found that the stimulation of the mucosa of the rhinopharynx elicits apnea and bradycardia in the duck. This appears to be the most important area involved in the production of diving responses. The laryngeal mucosa and other areas, as the external nares, were found to be of lesser relevance. We have also observed that visual and thermal stimuli may participate in the elicitation of the responses to submersion.

Acoustic Stimulation↗
PubMed1986

Neocortical and olfactory bulb activity, in armadillos submitted to covering with soil.

Armadillos were submitted to an experimental condition in which their head and thorax were covered by a layer of soil 30 cm high. In this condition the electrical activity of the neocortex and of the olfactory bulbs was studied. Neocortical activity did not show signs of damage remaining without gross changes before, during and after the covering with soil. The olfactory bulbs showed a great decrease of bursting sinusoidal activity which almost instantaneously reversed when the soil was removed. The mechanisms of these changes are discussed.

Animals↗
PubMed1984

Spatial learning in South American opossums and armadillos.

This experiment compares spatial learning in the South American opossum (Didelphis albiventris) and armadillo (Chaetophractus villosus) in a Y-maze. Ss learned to turn to one arm of the maze for food reinforcement. To earn further reinforcements, they had to return to the start-box (after consuming the food) where they were restrained for a fixed intertrial interval. The number of entries to the unbaited arm en route to the goal-box (Ri errors), and in the way back to the start-box (Rf errors) were the dependent measures. Opossums and armadillos did not differ in Ri errors. However, only armadillos mastered the task of returning directly to the start-box after each reinforcement. Moreover, a significant within-session improvement in Rf errors was observed in armadillos, but failed to appear in opossums. Results are discussed in terms of species differences in sensitivity to temporal delays.

Animals↗