Biomedical subjects

J Boya

Publications and source records attributed to J Boya.

At least 73 records · Page 4Linked to original sources

PubMed1979

Evolution of the pineal gland in the adult chicken.

The structural pattern of the pineal gland in the hen corresponds to a more advanced stage of the evolution which began in an early period of the animal's life. This evolution corresponds mainly to the transformation of the large follicular cavities into cellular 'rosettes'. The parafollicular layer disappears from the rosette wall which thus remains with only one row of cells (A and B pinealocytes). The cellular hypertrophy and the great development of the pinealocyte organelles in the adult pineal gland makes us think of this gland as a functionally active organ. This functional activity must have remained during the entire period of the time studied (1--5 years), due to the ultrastructural uniformity found and due to the fact that we could not observe any type of degenerative process in the gland.

Acid Phosphatase↗

PubMed1979

The origin of microglial cells.

The rat brain has been studied between 6 hours after birth and 100 days, using histochemical techniques for acid phosphatase and peroxidase, and silver impregnation for microglial cells. The results indicate that microglia come initially from acid phosphatase-positive cells of the meninges. These invade the nervous parenchyma and transform into ramified microglia. At 3 days of age similar cells are present on the outer surface of the large blood vessels, from which site they migrate into the nervous parenchyma. In 100 days old rats the acid phosphatase-positive cells are practically all pericytes. None of the microglial cells or their precursors give a positive reaction for peroxidase.

Acid Phosphatase↗

PubMed1978

Post-hatching evolution of the pineal gland of the chicken.

The authors studied the evolution of the pineal gland of the chicken (Gallus gallus) from hatching until 34 months of age. They describe the progressive decrease of the follicular cavities and the appearance of solid-looking cavities. The stroma increases with age, dividing the pineal parenchyma into territories of small caliber.

Age Factors↗

PubMed1978

Embryonic development of the pineal gland of the chicken (Gallus gallus).

A study of the embryonic development of the pineal gland of the chicken was performed with the optical microscope. The time of apparition of the first outline, as a derivative of the roof of the third ventricle, was fixed at 3 days. The major portion of the pineal parenchyma is derived from the frontal wall of the outline. All the vesicles and follicles were formed by solid mammilliform projections which subsequently presented a central lumen. In no case was a communication of the follicular cavities with the pineal recess observed. Three categories of vesicles or follicles can be distinguished according to their origin.

Animals↗

PubMed1976

An ultrastructural study of the relationship between pericytes and cerebral macrophages.

We studied, with the electron microscope, the normal cerebral cortex of white rats and zones adjacent to puncture wounds. The data obtained in this study, demonstrated the passage of pericytes to the nervous tissue, after the rupture of the basal membrane, and their transformation into macrophages. We suggest the possibility of the transformation of the pericytes into microglial cells.

Animals↗

PubMed1975

Contribution to the ultrastructural study of microglia in the cerebral cortex.

The author studied the ultrastructural characteristics of the microglial cell in the cerebral cortex of the adult rat and rabbit, admitting the identity and independence of this glial type in relation to the other cells of the nervous tissue. He also discussed the microglial nature of the pericytes ("pericytial microglia").

Animals↗

PubMed1975

Ultrastructural study of the pineal gland of the chicken (Gallus gallus).

The authors studied the pineal glands of chickens (Gallus gallus) between the ages of 2 and 5 days with the electron microscope. They described two distinct areas in the parenchyma of the organ: the follicles, formed by two cellular categories, the pineal A and B cells, and the parafollicular zone, which surrounds and separates the follicles from the connective walls. This area is formed, fundamentally, by two types of cells and nerve fibers. These cells occasionally delimit cavities. We propound the hypothesis of the possible transformation of the parafollicular zone into follicles.

Age Factors↗

PubMed1974