Biomedical subjects

A Verna

Publications and source records attributed to A Verna.

41 records · Page 3Linked to original sources

PubMed1975

Loss of chemoreceptive properties of the rabbit carotid body after destruction of the glomus cells.

Glomus cells of the rabbit carotid body were destroyed by local freezing. Electrophysiological recording of baroreceptor afferent activities showed that carotid sinus nerve regeneration was completed after 3 months. Nevertheless, ventilatory reaction as well as chemoreceptor afferent activity were no longer observed in response to the usual stimuli of arterial chemoreceptors (O2 test, NaCN). Results support the view that glomus cells are necessary for chemoreception and question the specificity of their afferent innervation.

Animals↗

PubMedDate not supplied

Long-term hypoxia increases the number of norepinephrine-containing glomus cells in the rat carotid body: a correlative immunocytochemical and biochemical study.

A group of adult rats was divided into two subgroups: one was submitted to long-term normobaric hypoxia (10% O2, two weeks) while the other (control group) was kept in the same room, breathing air. Animals from each subgroup were used to study either the norepinephrine content of the carotid body by high pressure liquid chromatography or to localize norepinephrine-containing structures using an immunocytochemical procedure (peroxidase-labelled antibodies on cryostat sections). The biochemical study showed, as expected, a large increase in carotid body norepinephrine content (19-fold) and turnover (ten-fold) in hypoxic rats. The immunocytochemical study revealed only a few norepinephrine-immunopositive glomus cells in sections through the carotid body of normoxic rats, whereas the carotid body of hypoxic rats showed a very large number of norepinephrine-positive glomus cells. This increase was quantified, using an image analyser, and it was found to constitute a 61-fold increase in the number of immunopositive profiles per section and a 29-fold increase in the immunopositive profile area/section area ratio. It is concluded that long-term hypoxia increases rat carotid body norepinephrine content by inducing norepinephrine synthesis in glomus cells in which this amine was not detectable previously, before hypoxia.

Animals↗

PubMedDate not supplied

Histopathological classification of lesions associated with natural paratuberculosis infection in cattle.

Paratuberculosis-associated lesions in 116 naturally infected adult cows, with or without clinical signs, were classified histopathologically. Tissue samples obtained focused on gut-associated lymphoid tissue. Lesions were divided into five categories. Focal lesions (n=68 cases), consisted of small granulomas in the ileal and jejunal lymph nodes or the ileocaecal lymphoid tissue. In the multifocal type (n=13 cases), small granulomas or scattered giant cells appeared in some intestinal villi, as well as in the lymph nodes. Diffuse multibacillary lesions (n=15 cases), associated with severe granulomatous enteritis affecting different intestinal locations and lymph nodes, were formed by macrophages containing large numbers of acid-fast bacilli. In diffuse lymphocytic lesions (n=3 cases), lymphocytes were the main inflammatory cells, with some macrophages or giant cells containing few if any mycobacteria. In diffuse intermediate forms (n=17 cases), the infiltrate was formed by abundant lymphocytes and macrophages, and mycobacteria were present to varying degrees related to the number of macrophages. Clinical signs and gross lesions were mainly associated with diffuse forms. Thickening of the intestinal wall, which was the most common macroscopical finding, was related to the degree of submucosal change. Mycobacterium avium subsp. paratuberculosis was identified by culture or PCR in all cows with diffuse lesions, and in 55.5 and 37% of those with multifocal or focal forms, respectively. The importance of sampling the ileal and caudal jejunal lymph nodes to find histological lesions of paratuberculosis in cattle is emphasized.

Animals↗

PubMedDate not supplied

Unexpected original property of elastin derived proteins: spontaneous tight coupling with natural and synthetic polymers.

Elastin fibres can be decomposed into their constituting proteins using several processes; in particular by saponification of some bonds with KOH in aqueous tertiobutyl alcohol, elastin solubilized proteins - ESP- of 10 to 200 KDa were produced with a good yield (70-80%). It is demonstrated that some of these proteins were capable of tightly re-associating with the native elastin fibres and remained bound on the fibres, in spite of several drastic washes using 1 M Guanidinium, HCl at 37 degrees C for 1 h. At pH 4-5, approximately 30-40 microg ESP were retained per mg elastin. The same association is also shown to occur, under similar conditions, with Poly-ethylene-terephthalate, Poly-hexamethylene diamine-adipic acid but not with polyurethanes. The optimal conditions of the coupling were described as depending on ESP concentration, time, pH, ionic strength and Ca++. It was also shown that opposite pH conditions, i.e. pH 14, 0.5 M NaOH, could allow the retained proteins to desorb from polyesters. Hence, it will be possible to determine the sort of proteins which could be involved. This property of ESP allows us (1) to better understand the exceptional capacity of tissue repair certainly due to adhesive properties of the artificial connective matrices containing elastin or ESP, developed in our laboratory, (2) to provide a new approach for elucidating elastin microstructure and function, (3) especially to provide a new mode for coating certain fibres, yielding materials with bioactive and biofunctional qualities.

Animals↗

PubMedDate not supplied

[Perioperative blood gas analysis in 100 patients in spontaneous respiration treated with ND-YAG laser for endoluminal tracheo-bronchial neoplasms].

OBJECTIVE: To determine the reliability on spontaneous ventilation of small continuously associated doses of ketamine and propofol during yag-laser therapy for upper airways neoplastic obstructions. DESIGN: Prospective description of blood gas analysis variation throughout the intervention and in the early postoperative period. SETTING: Operating theatre and postoperative Intensive Care Unit of the National Institute for Cancer Research. PATIENTS: A hundred consecutive cancer patients referred to our Institution for upper airways tumoral progressive obstruction. INTERVENTION: Yag-laser firing. MEASUREMENTS AND MAIN RESULTS: Pre-intra and postoperative blood gas analysis, BP, HR, Sat O2 have been registered every 10'. Mean intraoperative pCO2 rose to 47.3 mmHg (30-60), but within 2 to 3.20 hrs returned close to preoperative value (38.3 mmHg) allowing early patient discharge. CONCLUSIONS: The i.v. association of 0.7-1.0 mg/kg Ketamine and 1 mg/kg propofol, followed by 5 micrograms/kg/h and 3 mg/kg/h respectively, turned out to be satisfactory for both patients and anaesthetists in terms of anaesthesia and spontaneous breathing maintenance during yag-laser firing for obstructive upper airways cancer patients.

Adult↗