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Biomedical subjects

A Bron

Publications and source records attributed to A Bron.

At least 19 recordsLinked to original sources
PubMed2000

[Drugs and the eye].

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Adrenal Cortex Hormones↗
PubMed2000

Bronchial angiogenesis in severe glucocorticoid-dependent asthma.

To examine the role of the bronchial microvasculature and adhesion molecule expression in severe asthma, the authors have performed an immunohistochemical study on bronchial biopsies comparing 15 glucocorticoid-dependent asthmatics, 15 mild asthmatics and eight control subjects. Serially cut glycol methacrylate-embedded sections were stained with monoclonal antibodies identifying the vessel marker EN-4, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, E- and P-selectin. Sections were also stained for lymphocyte function associated antigen (LFA)-1 and very late antigen (VLA)-4. By comparison with mild asthma and nonasthma, severe asthma was characterized by increased numbers of submucosal vessels (p=0.009) which was associated with increased numbers of vessels expressing ICAM-1 (p=0.005). A highly significant correlation was found between the total number of EN-4+ vessels and the vessels expressing ICAM-1 (r=0.85, p=0.01). In contrast, E-selectin expression was lower in severe as compared with mild asthma (p=0.01) but not different from normal. No differences were found between the three groups in the expression of VCAM-1 and P-selectin nor in numbers of LFA-1+ and VLA-4+ cells. The results of this study support the notion that mucosal neovascularization is an important feature of airways remodelling in severe asthma. This is associated with a relatively higher density of vessels expressing intercellular adhesion molecule-1, although the expression of this adhesion molecule per vessel was not raised.

Adolescent↗
PubMed2000

Low-dose methotrexate treatment in severe glucocorticoid-dependent asthma: effect on mucosal inflammation and in vitro sensitivity to glucocorticoids of mitogen-induced T-cell proliferation.

The authors have investigated whether the steroid-sparing effect of methotrexate (MTX) in severe orally glucocorticoid-insensitive asthmatics may be accounted for by the ability of this drug to increase the T-cell responsiveness sensitivity to dexamethasone in vitro. In addition the authors have investigated whether low-dose MTX treatment is associated with anti-inflammatory effects in peripheral blood and the bronchial mucosa. In eight patients with severe atopic asthma, using > or =15 mg x day(-1) prednisolone, the inhibitory effect of dexamethasone on mitogen stimulated peripheral blood mononuclear cells (PBMC) in vitro was tested before and after 8 weeks of uncontrolled treatment with MTX. Endobronchial biopsies were taken before and after MTX therapy in seven subsequent patients, and analysed using immunohistochemistry. In eight patients, serum was drawn for measuring levels of free interleukin (IL)-8. The in vitro sensitivity of PBMC to dexamethasone (at 1.6 x 10(-9) and 3.2 x 10(-10) mol x L(-1)) was significantly lower in the asthmatics before treatment when compared with the control subjects (p=0.03 and =0.001) but increased significantly after MTX treatment (p=0.04 and =0.02) to normal responsiveness. This was not associated with a decrease in peripheral blood T-cell numbers or activation. Except for a significant increase in the numbers of CD3+ (p=0.04), no significant numerical changes in activated T-cells, eosinophils, or mast cells were found (p>0.05). However, MTX treatment was associated with a significant fall in serum levels of free IL-8 (p=0.03). It is hypothesized that the steroid-sparing effect of methotrexate originates from increased sensitivity of lymphocytes to the inhibitory effects of glucocorticoids. The absence of an inhibitory effect on inflammatory cells in blood and mucosa suggests that this effect is achieved by modulating cell function rather than cell number.

Adolescent↗
PubMed2000

[Accidental laser burn].

A student suffered an accidental parafoveal laser burn during a physics experiment. We discuss here the clinical features and management and follow-up. This case presents a good example of photic injuries which can occur in many different settings.

Accidents↗
PubMed2000

[Hemorrhage].

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Eye Hemorrhage↗
PubMed1999

[Infectious uveitis].

Half a century ago, bacterial diseases such as tuberculosis and syphilis were thought to cause the majority of cases of uveitis. Nowadays, a number of infectious diseases are responsible for uveitis. In our countries, herpes virus and toxoplasmosis are the principal causes of uveitis. Furthermore, because specific antimicrobial therapy can be curative and prevent long-term visual sequel, early diagnosis of infectious causes of uveitis should be a priority for all practitioners.

Adult↗
PubMed1999

Reflective meniscometry: a non-invasive method to measure tear meniscus curvature.

AIMS: To devise a method to measure tear meniscus curvature by a non-invasive specular technique. METHODS: A photographic system was devised. The system consisted of a camera and an illuminated target with a series of black and white stripes oriented parallel to the axis of the lower tear meniscus. The target was mounted on a flash gun close to the objective of a Brown macrocamera and calibrated using a graduated series of glass capillaries of known diameter, ground down to expose the inner wall. It was then applied to normal human eyes (n = 45) to measure the tear meniscus curvature. A video system was also assessed which provided qualitative online information about the tear meniscus. RESULTS: Using the photographic system, measured values for capillary radii were in excellent agreement with theoretical calculations (r2 = 0.996, p < 0.0001). The radii of curvature of lower tear menisci in normal human subjects (mean 0.365 (SD 0.153) mm, range 0.128-0.736; n = 45) were similar to those reported in the literature. Both systems demonstrated variations in meniscus shape. The video system provided stable images of human menisci over prolonged periods of time and promises to be useful for the analysis of dynamic changes in meniscus volume. CONCLUSIONS: Reflective meniscometry is a non-invasive technique providing quantitative information about tear meniscus shape and volume and of potential value in the study of ocular surface disease.

Calibration↗
PubMed1999

Mucosal inflammation in severe glucocorticoid-dependent asthma.

To improve our understanding of the inflammatory mechanisms underlying severe disease, a biopsy study was performed comparing 15 clinically unstable glucocorticoid-dependent asthmatics, 10 mild asthmatics, and 10 control subjects. Compared with mild asthma, severe asthma was characterized by reduced mucosal eosinophilia. Whilst no significant differences were found in the numbers of mast cells, neutrophils, CD3+ and CD4+ T-cells between the three groups, up to a 4-fold increase In the numbers of activated T-lymphocytes bearing the interleukin (IL)-2 receptor (IL-2R) was found in the mucosa in severe asthma compared to mild asthma (p = 0.03) and control subjects (p = 0.003). Compared to control subjects, the mucosa of severe asthmatics contained significantly (p = 0.02) higher numbers of IL-5+ cells, with no differences between mild and severe disease. In contrast, staining for the anti-IL-4 monoclonal antibody 3H4 revealed that biopsies from mild asthmatics contained more IL4+ cells than biopsies from severe asthmatics and control subjects (p = 0.0008). In the severe asthmatics, a close correlation (r(s) = 0.76, p = 0.005) was found between the numbers of IL-2R-bearing cells and the variability in peak expiratory flow. In conclusion, persistent T-cell activation is a prominent feature of severe asthma. These results also indicate that interleukin-5, and not interleukin-4, is upregulated in severe disease.

Administration, Topical↗
PubMed1999

[Is corneal thickness measurement reliable and useful?].

PURPOSE: We evaluated the accuracy and the reproducibility of central corneal thickness measurements using an ultrasound pachymeter, and its usefulness in clinical practice. METHODS: We calculated the intra-observer, inter-observer, and inter-session variability in control subjects (n = 38). We observed the diurnal variation (n = 8) and the role of surgery (n = 12) on central corneal thickness. We measured and compared central corneal thickness and intraocular pressure in 6 groups (control subjects n = 134, primary open-angle glaucoma n = 111, ocular hypertension n = 66, normal tension glaucoma n = 12, diabetes mellitus n = 62, corneal graft n = 27). We studied the influence of dorzolamide on central corneal thickness (n = 16). RESULTS: The intra-observer variability was 9 +/- 4 microns, whereas the inter-observer and inter-session variabilities were 4 microns and 5% m respectively. The central corneal thickness in patients with ocular hypertension (587 +/- 41 microns) was significantly greater than control subjects (548 +/- 32 microns) and all the other groups (p < 0.001). No influence of dorzolamide was observed on central corneal thickness. CONCLUSION: Central corneal thickness assessed with an ultrasound pachymeter may be a useful and accurate method in selected patients whose intraocular pressure measurement does not correlate with other clinical findings.

Adolescent↗