Biomedical subjects

M Barbara

Publications and source records attributed to M Barbara.

At least 37 records · Page 2Linked to original sources

PubMed1995

Glycolipidic component of the epithelial cell coat of the endolymphatic sac.

The endolymphatic sac (ES) is thought to synthesize and secrete glycoconjugates such as sulfated glycoproteins into the endolymphatic lumen. Ganglioside Gm1 is a specialized glycolipid containing one sialic acid molecule, which is generally found in the outer leaflet of the cell membrane. This glycolipid, which is known to be a specific receptor for cholera toxin (CT), acts as a membrane transducer and is involved in the modulation of cell metabolism, growth and regeneration. In the present study we identified Gm1 by studying the distribution of the FITC-labeled CT-subunit B in the ES epithelium of adult guinea pigs. Our findings indicate the presence of this ganglioside in the ES, with a predominant localization in the basolateral aspect of the epithelial cell layer. No detectable differences between ES cell types could be identified, whilst the ES distal and intermediate portions showed more reactivity than the proximal portion. This study, which represents the first description of a lipidic glycoconjugate component in the ES, provides evidence in support of the role of the ES in the turnover and regulation of inner ear fluids.

Animals↗

PubMed1994

Early hearing evaluation after microdrill stapedotomy.

Stapedectomy is known to give good results for otosclerosis. In this study, an audiometric evaluation of patients who underwent small-opening stapedotomy has been carried out at an early stage (3 and 5 days after surgery), and 1 month after surgery. At day 5 almost 60% of the patients showed a good functional result (mean residual post-op air conduction/pre-op bone conduction gap within 5 dB). While the timing of 4 kHz recovery overlapped that of the lower frequencies, recovery for 8 kHz was evident only at day 30, and was less likely to occur than for 4 kHz.

Audiometry, Pure-Tone↗

PubMed1994

Natural course of Menière's disease in surgically-selected patients.

Menière's disease (MD) is considered a complex otologic disorder characterized by exacerbation and remission periods which often make its natural course unpredictable. Several studies in the past have analyzed the evolutionary course of MD through comparison between patients under medical treatment and those surgically treated. The present paper aimed to study the evolution of MD in a group of patients who were selected for endolymphatic sac surgery on the basis of a fluctuating stage and uncontrollable recurrent vertigo; some of them, however, did not undergo surgery for different reasons and were used as control for MD at a homogenous stage. Vertigo and tinnitus were improved by surgery in a significant number of patients in comparison with the non-surgical group. Hearing function, which improved few months after surgery in some patients, was found to deteriorate in the long run, in surgical and non-surgical groups. Sac surgery yielded significantly better results for two out of three Meniere's symptoms, i.e. vertigo and tinnitus, and can be considered to play a significant role in the therapy of MD at the fluctuating stage.

Ear, Inner↗

PubMed1993

False-positive MRI in a patient with otoneurological pathology.

After a short survey on the diagnostic work-up for acoustic neuroma, the authors underline the importance of magnetic resonance (MRI), enhanced by gadolinium, for otoneurological pathology. Through the presentation of a clinical case, the pros and cons for the routine application of MRI in suspect cerebellopontine angle (CPA) tumours in particular are reviewed. The possibility of false-positive MRI findings is discussed, although in this specific case a proper therapeutic approach was eventually carried out in order to resolve the associated VIIth nerve disturbance.

Adult↗

PubMed1993

Initial experience of peroperative electrocochleography monitoring in stapedectomy.

Clinical experience of intraoperative ECochG monitoring during stapes surgery is reported. Selected surgical phases have been taken into consideration, laying particular stress on the phase corresponding to the opening of the labyrinthine spaces. Compound action potential (CAP) amplitude and latency showed, a supposed, an inversely proportional relationship in most of the cases. Abnormal findings were also recorded in some patients, thus giving rise to different electrophysiological hypotheses. A proposal for an "in vivo" model for the study of the electrophysiological changes due to the opening of labyrinthine spaces is made.

Adult↗

PubMed1993

Effect of intraoperative manipulation and preservation on fascia temporalis used in tympanoplasty.

Fascia temporalis (FT) is generally used as grafting material for primary or revision surgery for chronic ear disease. In the latter case, homologous FT, stored in various solutions after the intraoperative preparation, that aims to dehydrate, is often used. In this study, an ultrastructural analysis of FT has been carried out in order to determine whether its structure is affected by the different steps that take place before its application as a homograft. As well as light, transmission and scanning electron microscopy, immunoperoxidase technique for testing monoclonal antibodies against different collagen types was performed. The surface appearance of FT proved to be increasingly affected by the intraoperative manoeuvres. Moreover, 10% formalin proved to give a better preservation of the surface appearance of FT than did 70% alcohol which, also after a short period of preservation (15 days), caused severe surface alterations. No particular changes in the ultrastructural appearance of FT were noticed that could have been attributed to the length of preservation. Type IV collagen was detected in the 30-day samples of both alcohol- and formalin-preserved specimens. From these results, one can speculate that, despite the major ultrastructural changes induced in FT by the intraoperative preparation and by its preservation, this tissue is still able to maintain a proper connective network. This finding could explain the reliability of homologous FT for the repair of tympanic membrane perforations.

Ethanol↗

PubMed1992

Model of bronchial allergic inflammation in the brown Norway rat. Pharmacological modulation.

Exposure of non-sensitized Brown Norway (BN) rats to a 10%-ovalbumin aerosol induced an increase in the number of neutrophils in the broncho-alveolar lavage (BAL) fluid 3 and 6 h later but with no change in number of cells at 24 h. When the BN rats were actively sensitized (i.m. injection of 10 mg/kg ovalbumin and i.p. injection of killed Bordetella pertussis) and exposed 12-14 days later to a 10%-ovalbumin aerosol there was an increase in the number of eosinophils in the BAL fluid, maximal 24-48 h after the anaphylactic reaction. The increase in the number of neutrophils in the bronchial lumen 3 and 6 h after the anaphylactic reaction was larger than that obtained in non-specific inflammation and in contrast to this was still present 24-48 h after ovalbumin exposure. In passively sensitized BN rats exposed to ovalbumin aerosol, no inflammation appeared in the BAL fluid 24 h after the anaphylactic reaction. Various drugs, administered twice, 5 min and 5 h after the anaphylactic reaction, have been evaluated for their effects on the 24-h inflammation obtained in actively sensitized rats. Dexamethasone acetate (0.08 mg/kg i.p.) and theophylline (50 mg/kg i.p.) decreased the number of eosinophils and neutrophils. Ketotifen fumarate (12.5 mg/kg), cetirizine dihydrochloride (12.5 mg/kg), salbutamol (2 mg/kg), disodium cromoglycate (50 mg/kg) all given intraperitoneally, reduced the number of eosinophils. Tioxamast decreased the number of eosinophils at 12.5 mg/kg i.p. and by the oral route.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuterol↗

PubMed1991

Pharmacological modulation of a model of bronchial inflammation after aerosol-induced active anaphylactic shock in conscious guinea pigs.

Twenty-four hours after an active anaphylactic shock induced by inhalation of antigen in conscious guinea pigs sensitized by a large dose of ovalbumin in complete Freund's adjuvant, a noteworthy bronchial inflammation, characterized by increased numbers of neutrophils, mononuclear cells and eosinophils in the bronchoalveolar lavage fluid, was observed. Some drugs administered after the anaphylactic shock were investigated using this model. Disodium cromoglycate primarily reduced the number of mononuclear cells and eosinophils. Dexamethasone and theophylline decreased the number of eosinophils. Salbutamol and mepyramine increased neutrophils. Indomethacin did not give rise to any significant effect. This test appears to be of use for the investigation of anti-inflammatory compounds in the prophylactic treatment of asthma.

Albuterol↗

PubMed1991

Theophylline reduces pulmonary eosinophilia after various types of active anaphylactic shock in guinea-pigs.

The action of theophylline was studied on the inflammatory reaction obtained in bronchoalveolar lavage fluid 24 h after an active anaphylactic shock had been induced by ovalbumin inhalation in conscious sensitized guinea-pigs. The compound was administered twice by intraperitoneal administration after the anaphylactic reaction at a dose of 50 mg kg-1. When the guinea-pigs were sensitized by intramuscular injection of 30 mg kg-1 ovalbumin or by ovalbumin aerosol, theophylline reduced the number of eosinophils and mononuclear cells in the fluid. When animals were sensitized by intramuscular injection of 30 mg kg-1 ovalbumin mixed with Freund's complete adjuvant, treatment with the xanthine derivative decreased only the number of eosinophils. In the three models theophylline did not modify significantly the number of neutrophils. Thus theophylline always reduced pulmonary eosinophilia irrespective of the mode of sensitization used to induce anaphylactic shock.

Aerosols↗

PubMed1991

Vascular supply of the endolymphatic sac. A gross and ultrastructural study in the Mongolian gerbil under normal and experimental conditions.

The vascular network of the gerbilline endolymphatic sac (ES) and its dynamics were studied using different morphological procedures. The normal condition was compared to serum osmotic alterations induced by changing the daily water intake of the animals. The gross morphology was studied after intracardiac injection of Berlin Blue, while light (LM) and transmission electron microscopy (TEM) were applied for the ultrastructural analysis. A rich vascular supply was seen in the intermediate portion of the normal ES, and the presence of micropores and fenestrations confirmed also in this animal species the importance of this region for fluid exchange. The lacunar arrangement of the vessels in the distal portion of the ES, together with the close vicinity of this area to the bone marrow, led to the hypothesis that the distal ES possesses a functional role as blood reservoir. The hyperosmotic condition induced by water deprivation appeared to affect mostly the morphology of the red cells. In some of the capillaries, a thrombus-like occlusion was also evident. This vascular occlusive condition appeared to be partly reversible when water intake was reestablished, although the morphological alterations induced by the hyperosmotic condition to the subepithelial tissue appeared not to be reversible.

Animals↗

PubMed1991

Bronchial inflammation and hyperreactivity after anaphylactic shock in guinea pigs actively sensitized by systemic or aerosol route.

Hyperreactivity and bronchial inflammation resulting from active anaphylactic shock induced by aerosol have been studied in guinea pigs after sensitization by intramuscular injection of large-dose ovalbumin or aerosol ovalbumin. When animals were sensitized by i.m. injection of 30 mg/kg ovalbumin, hyperreactivity to inhalation of histamine was obtained 1-3 h after shock. In bronchoalveolar lavage (BAL) fluid an increase in the number of eosinophils (6-48 h after shock) and neutrophils (6-24 h) was observed. When guinea pigs were sensitized by aerosol route, the hyperreactivity to histamine inhalation appeared 1-6 h after shock. In BAL fluid the number of mononuclear cells dropped (1-3 h) and then increased (24-48 h); the number of neutrophils (6-48 h) and eosinophils (24-48 h) increased. The results observed during these two types of sensitization were compared to those obtained after sensitization by injection of a large dose of ovalbumin mixed with Freund's complete adjuvant.

Aerosols↗

PubMed1990

Model of bronchial hyperreactivity after active anaphylactic shock in conscious guinea pigs.

A model of bronchial hyperreactivity at various times after an active anaphylactic shock in conscious guinea pigs is described. The bronchial inflammation was quantified in parallel by determination of the number of mononuclear cells, neutrophils, and eosinophils in bronchoalveolar lavage (BAL) fluids. The guinea pigs were sensitized by an intramuscular (i.m.) injection of a large dose of ovalbumin in Freund's complete adjuvant. The administration of ovalbumin (to induce anaphylactic shock) and of histamine to investigate bronchial hyperreactivity was by aerosol. The bronchial hyperreactivity to histamine was observed 3-6 hr after the anaphylactic shock. In the BAL fluid a decrease (1-3 hr) and then an increase (24-48 hr) in the number of mononuclear cells was found as well as an increase in neutrophils (3-48 hr) and in eosinophils (6-48 hr). The hyperreactivity was not correlated with changes in one category of cell in the BAL fluid. This model constitutes one simple test for investigating bronchial hyperreactivity in conscious guinea pigs. Further work is needed to try to determine the possible inflammatory parameters responsible for the hyperreactivity.

Administration, Inhalation↗

PubMed1990

Antiallergic and anti-inflammatory action of tioxamast in rats. I. Antiallergic activity in vivo and in vitro.

Tioxamast (F 1865) is an antiallergic drug that, administered systemically, reduces anaphylaxis in various models in rats. This action is due mainly to the inhibition of the synthesis and release of certain mediators. Orally or intraduodenally administered tioxamast inhibits IgE-dependent passive cutaneous anaphylaxis (ED50 = 0.8 mg/kg), IgE-dependent passive pulmonary anaphylaxis (ED50 = 0.5 mg/kg), and IgG-dependent passive cutaneous anaphylaxis (ED50 = 0.6 mg/kg). It has little or not effect on the increase of cutaneous capillary permeability induced by various mediators. In IgE-dependent passive peritoneal anaphylaxis in rats, tioxamast reduces the release of histamine (IC50 = 0.024 micrograms/ml) and of beta-glucuronidase (IC50 = 0.102 micrograms/ml). Also, histamine release is inhibited in IgG-dependent peritoneal anaphylaxis (IC50 = 0.103 micrograms/ml). The antiallergic compound has less effect on the release of histamine induced by the compound 48/80 in the peritoneal cavity of rats (IC50 = 1.67 micrograms/ml). Tioxamast inhibits the synthesis in vitro of leukotriene B4 (LTB4) by peritoneal neutrophils from rats stimulated by A23187 (IC50 = 8.88 micrograms/ml). At higher tioxamast concentrations, metabolites of the cyclo-oxygenase pathway are inhibited at concentrations of the same order of magnitude as those that inhibit Naja naja phospholipase A2 (IC50 = 144 micrograms/ml). Tioxamast also reduces the production of free radicals by leukocytes from the pleural cavity of rats which had phagocytosed opsonized zymosan (IC50 = 5.21 micrograms/ml).

Anaphylaxis↗

PubMed1990

Antiallergic and anti-inflammatory action of tioxamast in rats. II. Anti-inflammatory action in vivo.

Tioxamast is an antiallergic drug that inhibits anaphylaxis in various models in rats, and it inhibits the release and synthesis of certain mediators of inflammation [see Tarayre et al., this issue]. Here we report that the drug also has an anti-inflammatory effect in vivo in various nonimmunological models in rats. It reduces zymosan-induced inflammation in the paw and pleural cavity, starting at doses from 1.5625 to 3.125 mg/kg given intraperitoneally. In pleurisy, tioxamast lowers the concentration of leukotriene B4 (LTB4) in the exudate, at doses from 50 mg/kg i.p. Also, at doses from 12.5 mg/kg i.p., the compound reduced PAF-acether-induced pleurisy and the concentrations of LTB4 and peptidoleukotrienes in the exudate. An anti-inflammatory action against carrageenin-induced edema of the paw was seen only at doses of 50 mg/kg i.p. or more. The anti-inflammatory and antiallergic effect of tioxamast makes it a potentially useful drug in the treatment of allergies in humans.

Animals↗

PubMed1990

Effect of mechanical trauma on the stapedial footplate after stapedectomy. A scanning electron microscopic study.

The possible occurrence of inner-ear trauma linked to stapedectomy was studied by scanning electron microscopy of the medial (or labyrinthine) side of human stapedial footplates after performing a hole with different instruments. The anatomic variations induced experimentally by the different procedures are presented in detail and discussed. Manual instruments were shown to induce irregularities on the rim of the hole, whilst the utilization of either electric or pneumatic drills produced more regular margins. Finally, laser-produced holes were also examined. Rather neat rims were observed, but the thermal effect produced by this device has to be considered the major parameter involved in a possible inner-ear postoperative trauma.

Humans↗

PubMed1990

Comparative actions of immunosuppressants, glucocorticoids and non-steroidal anti-inflammatory drugs on various models of delayed hypersensitivity and on a non-immune inflammation in mice.

Various models of delayed hypersensitivity (DH) were used in mice: contact hypersensitivity reactions to picryl chloride and oxazolone and reactions to methylated bovine serum albumin (MBSA) and sheep red blood cells (SRBC). Drugs of different classes were tested in these models by systemic treatment around the challenge period: non-steroidal anti-inflammatory drugs (cyclooxygenase inhibitors, and inhibitors of both cyclooxygenase and lipoxygenase); glucocorticoids and immunosuppressants (cyclosporin A. CsA; cyclophosphamide, Cy; methotrexate, Mtx; azathioprine, Aza). These compounds were also studied and compared for their effects on the 3-h and 24-h phase of the carrageenin mouse-paw edema (in which inflammation is maximal after 24 h). Non-steroidal anti-inflammatory drugs (including double inhibitors of cyclooxygenase and lipoxygenase) had little or no effect on DH models, except indometacin. Glucocorticoids inhibited all immune reactions except that to MBSA. Of the immunosuppressants, CsA reduced all the DH reactions while Aza mainly reduced the reaction to SRBC; Cy and Mtx were mainly active on SBRC and MBSA inflammations. On another hand CsA, Cy and Mtx were inactive on the 3-h phase but decreased the 24-h phase of carrageenin edema. At doses active on the DH models and on carrageenin inflammation, Cy induced a lasting blood leukopenia, but CsA and Mtx did not. This combination of tests in the mouse seems to be of interest to demonstrate any action on DH and any anti-inflammatory effect and to suggest whether these activities are related to a possible leukopenic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Lectin detection of carbohydrates in the endolymphatic sac.

The carbohydrate contents of the guinea pig endolymphatic sac were investigated by the use of lectins. The lumen of the endolymphatic sac was filled with stainable precipitate containing N-acetyl glucosamine, mannose, glucose, galactose and fucose. N-Acetyl galactosamine was also detected but in minute amounts. This composition corresponded to other areas in the inner ear, such as the cupula, the otolithic membrane and the tectorial membrane. The function of these carbohydrates may play an important role in preventing the lumen of the endolymphatic sac from collapsing as well as in regulating transepithelial fluid transport.

Acetylgalactosamine↗

PubMed1989

Does severe water deprivation affect the inner ear? An experimental study of the gerbilline endolymphatic sac.

Through an ultrastructural study of the endolymphatic duct (ED) and sac (ES) system, the effects of an impaired body fluid metabolism on the inner ear fluid environment in the mongolian gerbil has been evaluated. A dehydrative state has been determined depriving of water for both five and twelve days this desert animal, which is known to withstand long periods of water abstinence. The morphological changes of the ED and ES under these circumstances have been compared with those induced by ethacrynic acid intoxication. Although the cochlear partition did not show signs of damage, the ED and ES system seems to be negatively influenced by the dehydrative state and displays a marked imbibition of the subepithelial tissue, which at places shows accumulation of an organic matrix. A regulating role for the antidiuretic hormone on the inner ear fluids of the mongolian gerbil is also proposed and discussed.

Animals↗