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F Capron

Publications and source records attributed to F Capron.

At least 19 recordsLinked to original sources
PubMed1992

Towards continuous glucose monitoring: in vivo evaluation of a miniaturized glucose sensor implanted for several days in rat subcutaneous tissue.

A miniaturized amperometric, enzymatic, glucose sensor (outer diameter 0.45 mm) was evaluated after implantation in the subcutaneous tissue of normal rats. A simple experimental procedure was designed for the long-term assessment of the sensor's function which was performed by recording the current during an intraperitoneal glucose load. The sensor was calibrated by accounting for the increase in the current during the concomitant increase in plasma glucose concentration, determined in blood sampled at the tail vein. This made it possible to estimate the glucose concentration in subcutaneous tissue. During the glucose load, the change in subcutaneous glucose concentration followed that in blood with a lag time consistently shorter than 5 min. The estimations of subcutaneous glucose concentration during these tests were compared to the concomitant plasma glucose concentrations by using a grid analysis. Three days after implantation (n = 6 experiments), 79 estimations were considered accurate, except for five which were in the acceptable zone. Ten days after implantation (n = 5 experiments), 101 estimations were accurate, except for one value, which was still acceptable. The sensitivity was around 0.5 nA.mmol-1.l-1 on day 3 and day 10. A longitudinal study on seven sensors tested on different days demonstrated a relative stability of the sensor's sensitivity. Finally, histological examination of the zone around the implantation site revealed a fibrotic reaction containing neocapillaries, which could explain the fast response of the sensor to glucose observed in vivo, even on day 10. We conclude that this miniaturized glucose sensor, whose size makes it easily implanted, works for at least ten days after implantation into rat subcutaneous tissue.

Animals↗
PubMed1992

Benign lymphocytic angiitis and granulomatosis: a T-cell lymphoma?

Benign lymphocytic angiitis and granulomatosis is a T-cell lymphoproliferative disorder confined to the lung and corresponding to a low-grade angiocentric immunoproliferative lesion. Controversy remains as to whether these lesions are lymphomas. We report such a case in an 8-year-old patient with Burkitt's lymphoma in remission who presented with persistent bronchopneumopathy and bilateral pulmonary infiltrates on tomodensitometry. Surgical resection revealed the histologic changes of benign lymphocytic angiitis and granulomatosis. Immunohistochemistry showed no aberrant pan T-cell marker loss. Genetic analysis of frozen tissue by Southern blot DNA hybridization with probes to T-cell receptor beta- and gamma-chain genes and to the immunoglobulin heavy chain joining region gene (JH) identified no clonal rearrangement. Search for Epstein-Barr virus-DNA sequences by in situ hybridization and Southern blot analysis provided negative results. Our data imply that lowgrade angiocentric immunoproliferative lesions are not exclusively lymphomas but might represent a borderline lymphoproliferative disease (seen in the course of many diseases), perhaps corresponding to host immune response.

Burkitt Lymphoma↗
PubMed1992

Occupational hypersensitivity pneumonitis in a smelter exposed to zinc fumes.

A smelter exposed to zinc fumes reported severe recurrent episodes of cough, dyspnea and fever. Bronchoalveolar lavage showed a marked increase in lymphocytes count with predominance of CD8 T-lymphocytes. Presence of zinc in alveolar macrophages was assessed by analytic transmission electron microscopy. This is the first case of recurrent bronchoalveolitis related to zinc exposure in which the clinical picture and BAL results indicate a probable hypersensitivity pneumonitis.

Adult↗
PubMed1992

[Diagnostic criteria, physiopathology and etiology of intra-alveolar hemorrhage].

In the first part of this article the clinical and paraclinical criteria of intra-alveolar haemorrhages are reviewed. The principal signs and symptoms are dyspnoea, haemoptysis, anaemia and bilateral alveolar and interstitial opacities. Computerized tomography of the chest shows a non-systematized alveolar filling. In the second part, the cytological and histological criteria are considered; they are provided by examination of the alveolar lavage fluid and by lung biopsy. Finally, the main elements in the physiopathology and causes of these haemorrhages are successively described.

Anti-Glomerular Basement Membrane Disease↗
PubMed1992

[Pulmonary lesions in Wegener's disease. Report of the French Anatomo-clinical Research Group. Study of 40 pulmonary biopsies].

We report the results of a morphological analysis of 60 pulmonary biopsies gathered from a multi center study, organised by the clinico-pathological research group on Wegener's Disease under the auspices of the French Language Society of Thoracic Medicine. Forty of the sixty cases analysed were retained after indexing the histological aspects in order to specify their diagnostic value. Two groups of lesions were distinguished, which had different significance. Group A: These include the three major diagnostic criteria, which reinforce one another as they associate: 1) The polymorphoneutrophil microabscesses with limited central necrosis or an extended necrosis like the contours of a relief map. 2) An angiitis (arteries, veins, capillaries) with eccentric focal parietal crescent-shaped microabscesses. 3) Polymorphous granulomas with giant cells. Group B: In this group are the minor morphological observations (table II) of a lesser value and significance. 1) Acute or chronic lesions with alveolar haemorrhage, endogenous lipid pneumonia, xanthomatous granulomas, an organising pneumonia with an alveolitis. 2) Bronchial lesions: Bronchitis and necrotising bronchiolitis, which is more rarely follicular. 3) Sero-fibrinous or infiltrative neutrophil pleural lesions with focal microabscesses, elastolysis and elastophagia with giant cells in the elastic lamina. Thirteen cases presented with misleading lesions, which was a possible source of diagnostic error and led to a discussion of several associated disorders (Goodpasture's syndrome, and collagen disorder syndrome) or there may be systemic angiitis (Giant cell or lymphocytic) or also systemic or tissue eosinophilia (Churg-Strauss syndrome, bronchocentric granulomatosis) or necrotising bronchitis (atrophic polychondritis) or other forms of nodular interstitial fibrosis, such as histiocytosis X. We would like to stress the great polymorphic variation of the lesions and the difficulties which confront pathologists in the diagnosis of Wegener's Disease, above all when it is localised to the lung. There is value in finding at least one major diagnostic criteria which is associated with a minor criteria and with the help of the C.ANCA levels may lead to a narrow clinicopathological correlation and allows for a fairly precise approach to the diagnosis and identification of early or unusual lesions and thus to the early treatment of patients before irreversible renal failure appears.

Biopsy↗
PubMed1992

[Histologic examinations during bronchial endoscopy: bronchial and transbronchial biopsy].

Flexible fiberoptic bronchoscopy was introduced by S. Ikeda at the end of the 1960's and has enabled considerable progress to be made in the diagnosis of tumours but equally for interstitial pathology. The different techniques are described and the techniques of transbronchial biopsy are stressed as well as side effects and specific complications such as pneumothorax or haemorrhage. The handling and servicing of the biopsies and the laboratory techniques are detailed. It is the overall quality of these practical aspects on which a correct interpretation of these tiny fragments depends.

Biopsy↗
PubMed1991

[Histopathological diagnosis of diffuse interstitial lung diseases].

The histopathological diagnosis of chronic diffuse infiltrative lung diseases rests on elements provided by bronchoalveolar lavage, fibroscopic transbronchial biopsy and, less frequently, surgical lung biopsy. The microscopic study sometimes leads to an accurate diagnosis that fits with the clinical context, but in other cases the morphological evaluation is purely lesional and must be discussed in the light of clinical, radiological and functional data.

Biopsy↗
PubMed1991

[Wegener's granulomatosis. Therapeutic indications and follow-up course. Apropos of 5 cases].

Five cases of Wegener's granulomatosis treated with cyclophosphamide (CPM) and prednisolone are reported. Four of these patients received intermittent intravenous boluses of cyclophosphamide with the aim of improving the prognosis and renal function and at the same time to attenuate any haematological or vesical toxicity of CPM. The initial response to treatment by boluses of CPM was favourable in all cases but three patients presented with relapses, which were sometimes repeated and boluses of CPM did not enable a remission to be maintained at the time. Recourse to continuous oral therapy in place of bolus therapy proved viable for the maintenance of remission in two cases. The bladder and haematological tolerance to the bolus was satisfactory but an episode of severe neutropenia led to an adaptation of the dose of CPM. The intermittent administration above all the low cumulative dose of CPM obtained with the boluses will explain the better vesical and haematological tolerance observed depending on the capacity to maintain a prolonged remission. The indications for boluses of CPM in the treatment of Wegener's granulomatosis remain uncertain and do not seem to be totally without inconvenience.

Administration, Oral↗
PubMed1991

[Icterohemorrhagic leptospirosis with acute respiratory distress syndrome and pulmonary hemorrhage].

We report a case of the respiratory distress syndrome occurring in a patient with leptospirosis ictero-haemorrhagica (LIH). The respiratory failure was associated with pulmonary haemorrhage. There was a rapid favourable outcome after treatment with antibiotics and artificial ventilation. The diagnosis of LIH has been confirmed by serological examination. The mechanisms of the pulmonary disorder during the course of LIH were discussed.

Adult↗
PubMed1990

High-performance liquid chromatography analysis of circulating insulins distinguishes between endogenous insulin production (a potential pitfall with streptozotocin diabetic rats) and islet xenograft function.

Porcine islets of Langerhans were microencapsulated according to the alginate-polylysine procedure, and implanted into the peritoneal cavity of 15 streptozotocin-induced (70 mg/kg) diabetic rats (6000 microencapsulated islets per rat). In four animals, a sustained decrease in plasma glucose level below 8.3 mmol/l was observed for up to nine months. However, it was possible to recover microcapsules from the peritoneal cavity of only one rat, and they were found to be damaged and containing no detectable tissue. When insulin in the plasma of three of these animals was analysed by reversed phase high-performance liquid chromatography, only rat insulins I and II, but not porcine insulin was detectable, indicating unambiguously that at the time of analysis, the correction of diabetes in these animals was due to the function of the recipient's own pancreas rather than the continued, long-term, function of the implanted porcine islets. These data confirm that in this model of diabetes, function of the host pancreas can resume following islet transplantation, leading in turn to the potential for a major bias in the interpretation of the data. In the case of an islet xenograft, when the donor's and recipient's insulins can be separated by high-performance liquid chromatography, this non-invasive analytical method should prove useful for identifying the source of insulin in the circulation, and thus the relative functional status of the endogenous and transplanted islets.

Animals↗
PubMed1990

Comparative study of microencapsulated rat islets implanted in different diabetic models in mice.

Microencapsulated rat islets of Langerhans (alginatepolylysine microcapsules) were implanted into the peritoneal cavity of diabetic mice (500 rat islets per mouse) in order 1) to evaluate the ability of this xenograft in correcting hyperglycemia in different models of diabetes and 2) to examine the implanted material recovered from the recipients after several weeks. 1) In the high-dose streptozotocin model in Balb/c mice (n = 14), 6 had a sustained (over one month) decrease in plasma glucose concentration from 401 +/- 7 to 171 +/- 7 mg/dl, with no effect in the other. 2) In the low dose streptozotocin model in C57BL/6J mice (n = 17), plasma glucose levels decreased in 9 mice, from 439 +/- 27 to 180 +/- 30 mg/dl, and remained below 250 mg/dl up to 60 days. In 8 mice, only a transient effect was observed. Empty capsule transplantation had no effect. Plasma insulin in successfully transplanted mice was higher in fed than in fasted state. 3) Microencapsulated rat islets had no effect on plasma glucose in male NOD mice made diabetic by cyclophosphamide treatment (n = 10). Thus, microencapsulated rat islets can improve the diabetic state in some, but not all diabetic mice. In this study, microcapsules were consistently surrounded by an inflammatory reaction, which remains a major concern.

Animals↗