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Biomedical subjects

M Barbara

Publications and source records attributed to M Barbara.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1989

Carbohydrate content of the endolymphatic sac. A histochemical and lectin-labelling study in the Mongolian gerbil.

A secretory activity has recently been attributed to the endolymphatic sac (ES), as a possible way to contribute to the fluid balance of the entire endolymphatic compartment. Previous histochemical studies have indicated the existence of carbohydrate complexes in the secretory product, both neutral and acidic in nature. A thorough analysis of these compounds in the gerbilline ES was carried out using both transmission electron microscopic (TEM) histochemistry, using dialyzed iron and periodic acid--chromic--silver staining techniques, as well as immunoflourescence with fluorescein-labelled lectins (FITC-lectins). N-acetylglucosamine was found to be one of the major carbohydrate components both of the epithelial layer of the ES and of the luminal precipitate. Proofs for a local secretory activity and its intracellular pathway are presented, suggesting to be involved in the regulation of pressure and volume of inner ear fluids.

Acetylglucosamine↗
PubMed1989

Turnover of sulphur compounds in the endolymphatic sac: an autoradiographic study in the Mongolian gerbil.

Complex macromolecules are suggested to play an important role for the function of the endolymphatic sac (ES). As proposed in previous experimental studies, proteoglycans are supposed to be present in the ES. As they are composed of a proteic core linked to chains of glycosaminoglycans, chemical identification of the glycosaminoglycans is of particular importance, bearing in mind that all but hyaluronic acid contain sulphur. In order to follow the short-term turnover of sulphur in the ES, an autoradiographic study has been carried out in the Mongolian gerbil using 35S as tracer. Radioactive labelling of the gerbilline ES was controlled 15, 20, 30 and 60 min after intraperitoneal injection. While the first signs of the presence of radioactive sulphur were noticed after 20 min in the blood vessels and in the basal aspect of the ES epithelium, after 60 min it was possible to observe the presence of the tracer both within the epithelial cell layer as well as in the lumen of the ES. These findings are consistent with the presence of a fast turnover of sulphur molecules in the gerbilline ES.

Animals↗
PubMed1988

The surface morphology of the endolymphatic sac of the Mongolian gerbil (Meriones unguiculatus) (a scanning electron microscopic study).

A scanning electron microscopic study of the endolymphatic sac of the mongolian gerbil is presented. As described in other animal species and in man, three rather distinct regions on the epithelial surface can also be recognized in this rodent. Light and dark cells are seen to line the sac epithelium throughout. At the level of the intermediate portion, however, a different cell type--the granular cell--is present, with its luminal surface covered by large amounts of solid material. On the basis of light and transmission electron microscopic studies presented elsewhere, a higher degree of functional specialization in this portion of the gerbilline sac is proposed.

Animals↗
PubMed1988

Hypotheses on a possible role of some mediators in various inflammatory reactions on mouse ear.

Thanks to local application of various compounds that inhibit the effects or the synthesis of histamine, serotonin, prostaglandins, thromboxanes and leukotrienes, hypotheses are proposed about the possible role of these mediators in various experimental inflammations induced on mouse ear: reactions to arachidonic acid, croton oil and cantharidin (6-h and 24-h phases); primary irritation and delayed hypersensitivity reaction to picryl chloride; and semi-delayed (6-h) and delayed (24-h) hypersensitivity to oxazolone. Histamine seems to play a major role in the acute phase (6-h) of the reaction to cantharidin and in the primary irritation due to picryl chloride. Serotonin seems to be more involved in edema due to arachidonic acid and to croton oil and in the semi-delayed phase of hypersensitivity to oxazolone. Leukotrienes seem to have a more pronounced role in arachidonic-acid-induced inflammation and in the primary irritation and delayed hypersensitivity reactions to picryl chloride. Prostaglandins and/or thromboxanes might have some influence in edema due to arachidonic acid and to croton oil, and in the primary irritation reaction to picryl chloride.

Animals↗
PubMed1988

Psychologic evolution of patients with Menière's disease in relation to therapy.

The state of anxiety experienced by menieric patients indicates the importance of the psychologic component in this disease. Uncertainties as to the type of treatment that is actually curative for this disease have put doubts on the favorable outcome for patients referred for endolymphatic shunt procedures; some clinicians claim that in such cases surgery simply had a psychologic support function. To evaluate the effectiveness of such a statement, the authors have studied three groups of patients: patients who underwent surgery; patients who underwent medical treatment; and nonmenieric, otosclerotic subjects prior to surgery as a control group. The first group was further divided into subjects with and without improvement after surgery. The following personality tests were used: Minnesota Multiphase Personality Inventory, reduced version; Adjective Check List; State-Trait Anxiety Inventory; and Symptom Check List. The results relative to the whole menieric group show a tendency toward a state of dysphoria and more striking somatizations than in the otosclerotic group. In regard to the distinction between operated and nonoperated patients, the former group showed a personality with a strong neurotic trait associated with dysphoria and a state of free anxiety tending toward hypochondria. The outcome of the operation (improvement of the vertigo) does not seem to influence the personality of the subjects, even though there are signs of higher anxiety levels than in subjects without improvement.

Adult↗
PubMed1988

Comparison of the cutaneous/systemic antiinflammatory activity ratios for desonide and hydrocortisone in various experimental models.

The ratios of antiinflammatory activity after oral administration (oral ED50/cutaneous ED50) for desonide (Locapred) and hydrocortisone (hydrocortisone acetate) were compared in various nonimmunological and immunological experimental models on mouse ears: edema induced by croton oil; primary irritation due to picryl chloride; the acute phase (6 h) and the beginning of the chronic phase (24 h) of inflammation due to cantharidin; delayed contact hypersensitivity to picryl chloride; and the semi-delayed (6 h) and delayed (24 h) phases of contact hypersensitivity to oxazolone. These investigations showed that, besides having a better antiinflammatory effect, desonide had a better ratio of local activity to systemic effect in all the models. In addition, by contrast with orally active doses, locally active doses did not induce any thymolytic effect. Such results were confirmed in rats in which desonide reduced 24 h carrageenin abscess after cutaneous application without any significant thymolytic effect. Hydrocortisone was inactive.

Abscess↗
PubMed1987

Ultrastructure of the endolymphatic sac in the mongolian gerbil.

We describe our findings in an ultrastructural study of the endolymphatic sac of the mongolian gerbil. In conjunction with its specific renal physiology, enabling this animal to withstand long-term water deprivation, we have used our findings to hypothesize the existence of a local monitoring system within the endolymphatic space. The presence of elastic tissue in the subepithelial space of the endolymphatic sac could explain the mechanism through which this structure equilibrates endolymphatic pressure changes. Finally, we propose that a secretion of water-retaining macromolecules may act through osmotic forces to modulate inner ear fluid.

Animals↗
PubMed1987

Pharmacological modulation of PAF-acether-induced pleurisy in rats.

Injection of platelet-activating factor (PAF-acether) into the pleural cavity of rats induced the accumulation of a moderately intense exudate within 30 to 60 minutes. By comparison with animals given injections of the vehicle alone, the animals given this mediator had elevated levels of leukotriene C4-immunoreactive material (LTC4 im) in the exudate and decreased quantities of thromboxane B2 (TxB2) and of 6-Keto-F1 alpha-prostaglandin (6-Keto PGF1 alpha). Nifedipine, verapamil, and diltiazem reduced the pleural exudate with no major effect on the mediators. Both salbutamol and theophylline reduced the exudate and the levels of LTC4 im. Acetylsalicylic acid, phenylbutazone and indomethacin significantly inhibited the exudate, greatly lowered the quantities of cyclooxygenase derivatives and tended to increase LTC4 im. Phenidone, which inhibits the cyclooxygenase and lipoxygenase pathways, decreased the exudate and the three mediators. The phospholipase A2 inhibitor, chloroquine, decreased both the amount of exudate and moderately the concentration of LTC4 im. The glucocorticoids studied had no effect on the exudate or on the mediators. These results suggest that the role of the increased LTC4 im in the induction of the pleurisy is not clear.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Cutaneously applied erythromycin base reduces various types of inflammatory reactions in mouse ear.

Erythromycin base was tested by brushing a solution onto the skin in various models of non-immune and immune inflammation produced in mouse ear, namely inflammations induced by croton oil and cantharidin, primary irritation by picryl chloride, and contact hypersensitivity reactions to oxazolone and picryl chloride. On the non-immune inflammations, erythromycin displayed a greater effect than indomethacin, phenylbutazone or acetylsalicylic acid, though less than that of hydrocortisone acetate. It inhibited the hypersensitivity reactions less well. These results suggest some participation of an anti-inflammatory mechanism in the clinical effectiveness of cutaneously applied erythromycin base in some forms of acne.

Administration, Topical↗
PubMed1986

Inflammatory action of PAF-acether in the rat pleural cavity.

The injection of PAF-acether into the pleural cavity of the rat induced a maximal exudate after 30-60 min which then decreased and disappeared after 24 hours. In addition, the mediator produced a decrease in the number of leukocytes in the pleural cavity 30 min after injection and an increase in the number of cells after 6 hours.

Animals↗
PubMed1986

Rehabilitation of radical mastoidectomy.

Radical mastoidectomy has for years been the method chosen for the treatment of chronic middle ear disease. The numerous inflammatory problems linked to this cavity have been dealt with differently by various authors. We have examined the literature and refer to our own data, from a study carried out in twenty-four subjects, showing unsatisfactory results subsequent to a previous radical mastoidectomy. In ten of these subjects, middle ear cleft reconstruction was performed using a posterior canal wall prosthesis in Ceravital; in the remaining fourteen subjects complete obliteration with costal cartilage and a mixture of bone paté and fibrin glue (Tissucol) was carried out. In both groups the reconstruction of the conductive system was carried out by the insertion of total or partial ossicular replacement prostheses in Plastipore. The comparison of findings in the two groups revealed slightly better functional results in all two-stage procedures and in reconstructions performed with Ceravital. However, the one-stage procedure proved to be equally effective in resolving the inflammatory problems.

Biocompatible Materials↗
PubMed1985

Juvenile Menière's disease.

The authors report their experience in the diagnosis and treatment of Menière's disease in childhood. They believe it to be essential to carry out a complete battery of audio-vestibular tests, with particular reference to dehydration procedures, which in this age group are considered to be more significant for a correct diagnosis than in adults. After stressing the importance of eliminating other forms of disease which manifest themselves with vertigo, the authors conclude by asserting the efficacy of medical treatment with diuretics and they support the surgical procedure of endolymphatic-mastoid drainage as a valid means of contending with the hydrops.

Adolescent↗