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Biomedical subjects

H Perrot

Publications and source records attributed to H Perrot.

At least 37 records · Page 2Linked to original sources
PubMed1993

Study of immunoglobulin G thin layers obtained by the Langmuir-Blodgett method: application to immunosensors.

Nowadays, immunosensors play a leading part in the field of bioanalytical chemistry research. As with any biosensor, they need appropriate transducers and a suitable technique to immobilize the active biocomponents. In this study, two transduction modes were chosen: mass effects (quartz microbalance measurements) and geometric and dielectric effects (capacitance measurements). The Langmuir-Blodgett (LB) method appears to be quite suitable for generating biospecific surfaces. This work has focused on the detection of staphylococcal enterotoxin B, the corresponding antibody being immobilized at the surface of fatty acids by a variant of the LB method. The composition of the film and the nature of antibody-fatty acid interactions were studied by means of the two transducers mentioned above. FTIR (Fourier transform infra-red) spectroscopy and protein diagnostic assay. Influence of several parameters (pH, ionic strength, transfer pressure, antibody concentration in the subphase) was investigated. The immobilization rate reached its maximum when experimental conditions allowed optimal electrostatic interactions. In this case, the quartz crystal microbalance response, in air, reached 55 Hz per monolayer of immobilized immunoglobulin G and the equivalent capacitance variation, measured in liquid media, was around 300 pF cm-2. Activity of the biospecific LB films, when binding enterotoxin, was checked by the classical ELISA (enzyme immuno-linked assay) technique.

Antigen-Antibody Reactions↗
PubMed1992

Liver transplantation for erythropoietic protoporphyria. Report of a new case with subsequent medium-term follow-up.

We report a new case of successful liver transplantation in a 36-year-old patient with terminal hepatic failure due to erythropoietic protoporphyria. Data regarding protoporphyrin levels in erythrocytes and feces, before and after transplantation, seem to indicate that in this case protoporphyrin overproduction was in part due to liver synthesis. Four years after surgery, the patient is completely free of skin photosensitivity. His liver function tests are normal; there are no visible protoporphyrin deposits or ultrastructural abnormalities in his new liver. However, recurrence of the disease in the long term cannot be excluded, since erythrocyte protoporphyrin levels remained elevated after liver transplantation.

Adult↗
PubMed1992

[Superficial disseminated porokeratosis with dermal amyloidosis].

A case of non-actinic disseminated superficial porokeratosis with dermal amyloid deposits in a 53 year-old-man is reported. The lesions of the trunk and arms were typical, but annular lesions of the ankles were lichenoid. The amyloid deposits were present under the cornoid lamella in the typical lesions and absent in the annular lesions. The different clinical variants of porokeratosis are discussed. The origin of amyloidosis is debated; it seems to be epidermic, due to degeneration of the keratinocytes. The secondary cutaneous amyloidosis is usually described in association with epithelial tumors or psoriasis, but exceptionally with porokeratosis.

Amyloidosis↗
PubMed1987

[Barraquer and Simons lipodystrophy. Complement anomalies and cutaneous leukocytoclasic vasculitis].

In a 56-year old woman progressive partial lipodystrophy began at the age of 6 years on the face, thereafter extending slowly down to mid-thigh level (fig. 1 and 2), with moderate hypertrophy of the subjacent fatty tissue and a fatty macroglossia (fig. 3). Histological examination of the lipodystrophic skin not only showed an absence of fatty tissue, but also abnormalities at the dermis-epidermis junction with hyaline bodies (fig. 4). At the age of 23 she developed purpura, predominantly on the legs, which rapidly became chronic (fig. 5); histological examination showed leucocytoclasic vasculitis of dermal vessels (fig. 6) with granular deposits of C3 on the vessels and of IgM at the dermis-epidermis junction. Episodes of polyarthralgia and headaches were frequent. Regressive neuritis of the external popliteal nerve occurred when she was 53-year old. Renal function tests proved normal, but renal biopsy was not performed. There was no diabetes mellitus, but an oral glucose tolerance test and a somatostatin insulin glucose test elicited definite resistance to insulin. A search for a serum factor inhibiting insulin receptors was negative. Permanent abnormalities in serum were a very deep fall in C3, a pronounced fall in CH50 and a low C4 level. Besides, a C3 nephritic factor (NeF) at a high level and circulating immune complexes were present (table I); a mixed IgM-IgG cryoglobulin was found intermittently (fig. 7). Clearance of the immune complexes by splenic macrophages was extremely slow. During a series of plasma exchanges, serum C3 increased transiently, whereas serum C4 remained unchanged (fig. 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Complex↗
PubMed1986

[Ito's hypomelanosis. Review of the literature apropos of 3 cases].

Initially described as incontinentia pigmenti achromians, Ito's hypomelanosis is a congenital disease characterized dermatologically by depigmented maculae arranged in a specific pattern. These maculae appear suddenly, unheralded by an inflammatory process, and are arranged on the limbs as lines and on the trunk as whirlwinds or mottled cakes. Other abnormalities, notably neurological, ophthalmic or musculoskeletal may be associated with this spray-like depigmentation of the skin. We report here three cases of this disease, which is probably more common than the scarcity of cases hitherto published would suggest. Case no. 1. A 9-year-old boy presented since the age of 5 with generalized convulsive fits predominant on the right side. Neurological examinations between fits were negative. IQ, FO and CT scans of the brain were normal. During the first months of life, the child had developed a spray-like depigmentation on the right half of his back and on the anterior and posterior aspects of his right arm. Case no. 2. A 2-year-old girl was examined for a cutaneous depigmentation which had developed when she was about 3 months' old and had progressively extended from her left knee to her left hypochondrium. Case no. 3. An 8-year-old girl presented with mental retardation and myopia, but also with a spray-like depigmentation on the left part of her chest. The skin lesion had been noticed by her parents after she had exposed herself to the sun in a tropical country. Histological examination performed in the first two patients showed some degree of hypopigmentation of the epidermis without pigmentary incontinence.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1983

[Clear cell acanthoma. Ultrastructural and immunohistological study].

We report a new case of a clear-cell acanthoma with an unusual location (para-anal), which was studied by electronmicroscopic and immuno-histological methods, using monoclonal antibodies. The results of this study showed that: a) the inflammatory cellular infiltrate comprised a small number of T-suppressor/cytotoxic lymphocytes and a small number of Langerhans cells, b) Langerhans cells were present in the affected epidermis in reduced numbers (2.2 p. 100) when compared to normal epidermis (4-6 p. 100), c) there was a disorder of both keratinization and epidermal differentiation as was shown by the abnormal reactivity of the tumor to monoclonal antibodies KL1 and BL7, d) human papilloma viruses do not seem to be involved in the genesis of the tumour, e) tumoral cells did not show (secretory) eccrine differentiation, f) the pemphigus antigen was present in the intercellular space of the affected epidermis.

Anal Canal↗