Biomedical subjects

F Giannessi

Publications and source records attributed to F Giannessi.

41 records · Page 3Linked to original sources

PubMed1981

Toxic effect of carrageenan on lymphoid-follicle associated epithelial cells of the bursa of Fabricius of chickens.

The lymphoid-follicle associated epithelial (FAE) cells of the bursa Fabricii of chickens show enzymatic and micropinocytotic activities; they can perform functions reminiscent of those of macrophages. To test this relationship, we checked whether FAE cells are sensitive to carrageenan, a substance widely known to be toxic for macrophages. This substance was gently introduced into the bursal lumen and was left there for a period of 72 to 120 h. The bursae of Fabricius were then examined histologically and histochemically. The result was that the FAE areas had been reduced in number and that their structural pattern had been modified. This effect suggests that FAE cells may be sensitive to carrageenan. The immunological response to SRBC was studied in one group of animals that had received carrageenan. The antibody seemed to elicit an increase in the agglutinins and in the number of direct PFC/spleen against SRBC in comparison with control chickens. On the basis of the morphological and immunological results obtained, the origin and the role of the FAE cells of the bursa of Fabricius are discussed.

Animals↗

PubMed1980

[Horseradish peroxidase (HRP) in intravenous administration is not present in the bursal lumen after interruption of the connection between the bursa and cloaca].

A surgical technique, which we recently described, was used to interrupt the anatomical connection between the bursa of Fabricius and the cloaca. This was done in order to ascertain whether H.R.P. e.v. injected into the wing vein might reach the bursal lumen through the follicle associated epithelial cells, as suggested by Bockman and Stevens, or to establish whether, on the contrary, the way used by H.R.P. to gain access to the bursal lumen might be another:e.v. injected H.R.P. may be excreted by the chicken kidneys, as we demonstrated, then it may pass into the bursal lumen through the cloaca thanks to the duct connecting the two organs. In the present paper we show that the interruption of this connection prevents e.v. injected H.R.P. from gaining access to the bursal lumen.

Animals↗

PubMedDate not supplied

Ultrastructural localization of NADPH-diaphorase activity in the endothelial cells of human nasal respiratory mucosa.

The cavernous sinuses are the most peculiar feature of the nasal angioarchitecture, due to their ability to retain a large quantity of blood in reply to a variety of topical and systemic stimuli. Recently, nitric oxide (NO) has seemed to be crucially involved in the nasal vascular regulation. The distribution of NO-synthase (NOS), the enzyme that catalyzes the formation of NO, was studied in the endothelium of nasal blood vessels by the ultracytochemical detection of reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) enzymic activity. The endothelium of the cavernous sinuses appeared strongly positive, whereas the endothelium of arterioles was occasionally labeled. The endothelial cells of capillaries and venules were found to be NADPH-d negative. The strong enzymic activity observed in the cavernous sinuses suggests a major role of NO in the capacitance vessels compared to the resistance vessels. The hypothesis of a reciprocal inhibition between the NOS enzymic pathways present in the respiratory epithelium and in the endothelium of cavernous sinuses is put forward. The nasal disorders characterized by anomalous vasomotility and vascular permeability could be caused in part by the irregular control of these complex interactions.

Adolescent↗

PubMedDate not supplied

Changes in the chicken bursa of Fabricius and immune response after treatment with melatonin.

Since melatonin causes considerable reduction in the thymic weight of chickens, the aim of the present study was to find out whether the bursa of Fabricius and the immune response are also affected by this substance. The results show that melatonin also acts on the bursa of Fabricius depending upon the administration route. When injected subcutaneously it does not reduce bursal weight and the histological pattern does not change, while primary and secondary immune responses are significantly lowered. When melatonin is introduced into the bursa, it causes a considerable decrease in bursal weight and the histological pattern is greatly modified. A significant reduction in antibody production is observed involving the primary immune response alone. Transmission electronic microscopy seems to show that melatonin affects the reticulo-epithelial (REp) cells.

Animals↗

PubMedDate not supplied

Ultrastructural demonstration of the NADPH-diaphorase activity in peritubular myoid cells and fibroblasts of the lamina propria of the mouse seminiferous tubules.

The NOS-related NADPH-diaphorase activity was studied by transmission electron microscopy in the peritubular myoid cells and fibroblasts of normal mouse testis. The reaction product was observed on the membranes of the endoplasmic reticulum, on the Golgi apparatus and nuclear envelope. The peritubular myoid cells and fibroblasts showed similar ultracytochemical features; the intensity of the enzymatic reaction was suggestive of an important role of the NOS/cGMP enzymatic system in these cells. Some hypotheses on the role of NO in the peritubular myoid cells and fibroblasts are proposed.

Animals↗