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Biomedical subjects

E Parrat

Publications and source records attributed to E Parrat.

9 recordsLinked to original sources
PubMed2001

Electrophysiological effects of corticosteroids on the retinal pigment epithelium.

PURPOSE: As corticosteroids appear to intervene in pathogenesis of central serous chorioretinopathy, ion transport changes within the retinal pigment epithelium (RPE) might be involved. Electrophysiological responses to corticosteroid administration were recorded in vivo and in vitro. METHODS: Clinical study: The standing ocular potential was recorded during intravenous (IV) infusion of glucose 5% and glucose 5% + prednisolone 0.2% in 14 patients with relapsing multiple sclerosis. The results were compared with a control group receiving two successive identical glucose 5% infusions. In vitro study: Native tissue explants (RPE + choroid, porcine, and bovine) were placed in a Ussing-type chamber. After baseline determination of the transepithelial potential (PD), short circuit current (I(sc)) and transepithelial resistance (R(t)), the effect of apical hydrocortisone (HC) 10(-4) M was determined. RESULTS: Clinical study: A significant rise of the standing potential was found after glucose infusion (P = 0.005), whereas no change was detected after IV glucose + prednisolone (P = 0.695). In vitro study: In the porcine RPE, the mean baseline PD and I(sc) were significantly reduced (both P: = 0.012) after applying apical 10(-4) HC. R(t) was also significantly reduced (P = 0.01). The same type of response, observed in bovine RPE, was reduced in low chloride/low bicarbonate conditions. CONCLUSIONS: Corticosteroids modified electrophysiological parameters representing RPE function in vivo. The existence of an RPE-specific effect was confirmed in vitro. Further work is required to link the observed ion transport changes to a reduction of apical, subretinal fluid absorption.

Animals↗
PubMed1999

[Fuchs' uveitic syndrome in a patient with ocular toxoplasmosis].

We report a case of Fuchs' uveitic syndrome associated with toxoplasmic chorioretinis scars, and a positive Desmonts' coefficient. This allows us to emphasize ocular toxoplasmosis as a main association to be searched for clinically. In the cases in which this association is found, it would be warranted, if a high level of specific antitoxoplasmic antibodies is demonstrated in aqueous humor, to consider toxoplasmosis as one of the potential etiopathogenic factors of the Fuchs' uveitic syndrome.

Adult↗
PubMed1998

[Biological perspectives].

The tumour biology of non-small cell bronchial cancer integrates recent developments and a dynamic schema of the phenomena of tumour progression and diffusion of the metastatic disease. There is no leap of known biological disruption between Stage II and Stage III. The latter is defined by anatomical criteria and is a transition in the continuum of the natural history of these cancers. The moto for the tumour progression is the genotypic instability and phenotypic diversification. Metastatic microscopic disease constitutes the first cause of failure in the treatment of Stage III non-small cell bronchial cancer. Among prognostic factors for survival emphasis is placed on the alterations of p53 expression, different types of aneuploidy, anomalies of the expression of cellular adhesion molecules and finally, tumour diversification towards a metastatic phenotype.

Aneuploidy↗
PubMed1997

[Retinochoroidal involvement of type II membranoproliferative glomerulonephritis. An angiographic study with indocyanine green].

PURPOSE: Type II measangiocapillary glomerulonephritis is related to dense deposits within the glomerular basal membrane and the basal membrane of the pigment epithelium (Bruch's membrane). Being a vasculitis, an angiographic study by indocyanine green (ICG) could possibly enlarge the semiologic features of this disease. METHODS: The indocyanine green angiographic changes in 3 patients with predialitic renal failure due to type II measangiocapillary glomerulonephritis (MCGN II) (dense deposit disease) are reported. A complete ophthalmologic examination, electroretinography, electro-oculography, fluorescein and indocyanine green angiography (ICG) were performed for each patient. RESULTS: Abnormal hyperfluorescent dots were seen on the same part of the fundus on both fluorescein and ICG angiography, though these locations were different for each of the three patients. These results seem to link the deposits to vascular changes within the choriocapillaris, which opposes them to drusen encountered in age related macular degeneration (ARMD). It appears that the choriocapillary lesions could be similar to the glomerular disease. CONCLUSION: Beyond the diagnostic challenges related to the nephrologic disease, it is known that subretinal neovascularization occurs in some cases of MCGN II, although the pathophysiologic mechanism of the deposits is probably not the same as in ARMD. Therefore, ICG angiography should be performed when MCGN II is first known, serving as an initial examination for further follow-up.

Adult↗
PubMed1996

Lung cancer chemotherapy. Response-survival relationship depends on the method of chest tumor response evaluation.

In a previous study we found that tumor responses as assessed by CT scan and fiberoptic bronchoscopy are sometimes discordant. We hypothesize that the response-survival relationship might vary according to the method of tumor response assessment. In a multivariate analysis of survival using the landmark method, we evaluated the prognostic significance of tumor response assessed by CT scan or fiberoptic bronchoscopy together with bronchial tumor location and histology of bronchial biopsies at restaging. A total of 133 lung cancer patients (50 small cell lung cancers and 83 non-small cell lung cancers) were entered in controlled chemotherapy trials and prospectively evaluated for chest tumor response by CT scan and fiberoptic bronchoscopy (FOB). Only 106 patients were fully evaluable for response by both methods. For these patients, a statistical concordance was observed between the two tests (kappa = 0.271; p < 0.001). There was a significant correlation between response and survival whatever the test used. However, only CT scan evaluation resulted in a classification showing that the more unfavorable the response stage was, the worse the survival became with no intersection between survival curves. Cox's hazard model demonstrated that CT-evaluated progression, proximal bronchial location at second FOB (intermediate, main bronchus or trachea) and positive histologic status at restaging were all prognostic determinants of poor survival. In conclusion, CT-evaluated response led to the best response-survival relationship as this method classified patients into four groups with different outcomes. Fiberoptic bronchoscopy should be avoided in patients who were found to have no endobronchial lesion during the pretreatment staging. For patients with pretreatment assessable endobronchial lesions, the decision of a second FOB depends on the results of CT restaging: FOB is probably unnecessary in patients for whom progression is disclosed by CT scan. In patients for whom CT scan discloses tumor response or stabilization, bronchial tumor location and histology of bronchial biopsies at second FOB are independent prognostic factors.

Adenocarcinoma↗
PubMed1996

Cytokeratins as serum markers in lung cancer: a comparison of CYFRA 21-1 and TPS.

We examined two recently described cytokeratin markers, CYFRA 21-1 (cytokeratin fragment recognized by KS 19-1 and BM 19-21 antibodies) and TPS (specific M3 epitope of the tissue polypeptide antigen), in 405 lung cancer patients (91 small-cell and 314 non-small-cell lung cancers) and 59 patients presenting with nonmalignant pulmonary disease. Sensitivity-specificity relationship, as analyzed by receiver operating characteristic curves, demonstrated a higher accuracy of CYFRA 21-1 in comparison with TPS in both small-cell and non-small-cell lung cancers. Thresholds of 3.6 ng/ml and 140 U/L for CYFRA 21-1 and TPS respectively gave a 90% to 95% specificity. Sensitivity of CYFRA 21-1 was the highest in squamous-cell carcinomas (0.61) and the lowest in small-cell lung cancers (0.36), whereas sensitivity of TPS did not vary significantly according to histology (overall sensitivity, 0.40). In non-small-cell lung cancers, both serum CYFRA 21-1 and serum TPS distributions varied significantly according to Mountain's stage of the disease, nodal status, tumor status, and performance status, inasmuch as the worse each above-mentioned variable became, the higher the median and interquartile serum marker level was. Neither CYFRA 21-1 nor TPS was able to accurately discriminate between stage IIIa (marginally resectable) and stage IIIb (unresectable) non-small-cell lung cancers, however. In both small-cell and non-small-cell lung cancers, univariate survival analyses demonstrated that either a CYFRA 21-1 level over 3.6 ng/ml or a TPS level over 140 U/L significantly indicated a poor survival rate. In the whole population, taking into account other significant variables, Cox's model analysis demonstrated that a poor performance index, an advanced stage of the disease, the presence of metastases, elevated serum lactate dehydrogenase, and high serum CYFRA 21-1 (odds ratio, 1.74; 95% confidence interval, [1.33-2.27] were independent prognostic variables. We concluded that CYFRA 21-1 is a significant determinant of survival. Other applications of cytokeratin markers in lung cancer are still limited.

Adult↗
PubMed1995

[Evaluation of tumor response during chemotherapy of bronchial cancer].

Chemotherapy of lung cancer is still an experimental approach requiring careful evaluation. Tumour response (marker of anticancer activity) is not perfectly correlated to survival (marker of chemotherapy efficacy), but its evaluation remains a milestone inasmuch as reporting a wrong tumour response rate might lead to the rejection of active new treatments. This review deals with the method of tumour response measurements and its use during a chemotherapy protocol. Recommendations drawn from the analysis of the literature are: 1) to assess and classify all lesions which can be identified at the beginning of the treatment; 2) to define the target lesions, mainly the ones which can be bidimensionally measured; 3) to use the World Health Organization recommendations for reporting the overall response; 4) to confirm complete response by negative rebiopsies; 5) to avoid second fiberoptic bronchoscopy to patients with stable or progressive disease on CT-scan, and finally; 6) to assess response quality by evaluating response duration and improvement of quality of life.

Antineoplastic Agents↗
PubMed1993

Chest tumor response during lung cancer chemotherapy. Computed tomography vs fiberoptic bronchoscopy.

Tumor response is one of the most important criteria in the analysis of chemotherapy. A chest computed tomographic (CT) scan and fiberoptic bronchoscopy (FOB) might give different results, as they analyze different aspects of the effects of chemotherapy on lung cancer. The response of the chest tumor in 103 patients with stage III or IV lung cancer (35 with small-cell lung cancer [SCLC] and 68 with non-small-cell lung cancer [NSCLC]) who prospectively entered chemotherapy trials was studied in order to determine the concordance between the chest CT scan and FOB. The chest CT scan allowed an assessment of tumor response in almost all patients, whereas FOB was not able to evaluate this response in 15 of the 103. The frequency of an evaluable endobronchial lesion did not depend on histology (SCLC, 97 percent; NSCLC, 93 percent; chi 2 = 0.85; not significant [NS]) or tumor T classification (T1-2, 83 percent; T3, 94 percent; T4, 97 percent; chi 2 = 1.49; NS). Tumor location in the bronchial airway did not differ when SCLC and NSCLC were compared. Thus, it is not possible to predict a subgroup of patients in whom FOB may be optional. In the group of 88 patients who were evaluable for response using both FOB and CT scan, a statistical concordance of the response classification was observed. The response was overevaluated by CT scan in 22 patients for whom data obtained by FOB appeared to be critical in the evaluation of tumor response. The concordance of response data obtained when the 2 methods were used was lower in NSCLC in comparison with SCLC. Thus, the use of FOB in the analysis of tumor response might be important, especially for NSCLC, inasmuch as FOB modulates the CT-evaluated response.

Adult↗