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Biomedical subjects

A C Levi

Publications and source records attributed to A C Levi.

28 records · Page 2Linked to original sources
PubMedDate not supplied

Experimental investigation on histocompatibility of bovine collagen in rat tongue.

Authors injected a 1.5-2 cc Gax-Collagen into the tongue of 13 rats in order to examine the reactivity of the tissues around the graft and its attitude and duration. The research had practical purposes as the material is mainly used in E.N.T. for reconstructing the vocal cords. The animals have been sacrificed from 1 day to 9 months and the tongue subjected to the ordinary histologic methods. Our conclusions are as follows: a) a moderate inflammatory reaction following the introduction of the foreign body, then it attenuates and disappears at the third month; b) the implant is well tolerated, does not cause structural alterations in the surrounding tissues, in particular in the musculature where it is placed; c) a neovascularization appears, it lessens over the time, keeping itself only at the edge of the graft; d) in the formed fissures, fibroblasts, traces of collagen and neocollagen are present. All these conditions allow for taking root and the persistence of the implant. It is remarkable that the spherical form of the Gax-Collagen does not modify even if it has been implanted into a muscular organ and therefore subjected to severe and continuous mechanical stress.

Animals↗
PubMedDate not supplied

Questions about the uncertain presence of muscle spindles in the human external anal sphincter.

The verification of the uncertain presence of muscle spindles in the external anal sphincter is important in the comprehension of the pathophysiology of continence. The authors failed to demonstrate these proprioceptive structures in 10 human sphincters examined with different histological techniques, whereas they found some typical muscle spindles in the puborectalis muscles. The possible interpretations of the different results on the subject in the literature together with their functional implications are discussed.

Adult↗
PubMedDate not supplied

[Melanocytes in the epithelium of the gingival mucosa in different conditions of edentia].

Gingival crest melanocytes were examined in partial and total edentulates (with and without prostheses). Where the epithelium showed signs of epidermisation, the cells displayed their normal form and melanogenetic activity. In the presence of involution (acanthosis, reduction of the surface layers, smallcell infiltration), they withdrew their typical cytoplasmic expansion, while the Dopa reaction revealed poor thyrosinase activity. It is felt that these patterns confirm the epithelio-melanocyte symbiosis theory put forward by Quevedo et al. One total edentulate with a mucosally supported prosthesis displayed Dopa-positive dendritic cells on the gingival corium and tunica propria. These are seen as true melanocytes that had migrated from the epithelium.

Adult↗
PubMedDate not supplied

Preliminary spectroscopic studies on the neuromelanic pigment of human substantia nigra nucleus.

The neuromelanic pigment obtained from human mid-brain Substantia Nigra Nucleus was studied by I.R. spectroscopy and compared with synthetic dopamine melanin. Natural neuromelanin and synthetic dopamine melanin show very similar features in two characteristic I.R. absorption regions: 1400 cm-1, typical of phenolic OH groups, and 3200 cm-1 band, typical of aminic groups. Natural mid-brain neuromelanin shows a different absorption in the I.R. region at 3000 cm-1 and in the 1300-900 cm-1 range probably due to the presence of lipidic residues bound to the molecule. The results of the U.V. spectroscopic analysis suggest a correlation between the optical density of human neuromelanic pigment and the different ages of the subjects providing the specimens.

Adult↗
PubMedDate not supplied

Observations on surgical anatomy for rectal cancer surgery.

BACKGROUND/AIMS: The investigators studied the surgical anatomy of the main structures involved in the mobilization of the rectum (Denonvilliers' fascia, mesorectum, middle rectal artery, superior and inferior hypogastric plexuses). METHODOLOGY: The study was carried out on 20 cadavers (17 unembalmed and 3 embalmed). To study Denonvilliers' fascia, ten embryos and fetuses (11 mm to 80 mm CRL) were also examined. RESULTS: Denonvilliers' fascia originates from the fusion of the primary pouch of Douglas. The two leaves making up this structure are easily separated. The mesorectum surrounds the rectum on three sides; it is easily separated from the presacral fascia and its connective tissue is bordered by a thin membrane. The middle rectal artery varies in appearance rate, origin, size, distribution and anastomosis. It runs under the lateral ligament and also sends branches to the genital apparatus. Of the two hypogastric plexuses, the inferior is the most difficult one to identify. Its superior branches extend to the rectum, and the inferior ones to the genital apparatus. Because the anterior part contains the parasympathetic nerves and the middle rectal artery, this region is at major risk during surgical dissection. CONCLUSIONS: A sound understanding of the surgical anatomy of the rectum enables the surgeon to perform a more correct and reasonable procedure in terms of both the extent of surgical treatment and the preservation of important anatomical structures.

Adolescent↗