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Biomedical subjects

H Perrot

Publications and source records attributed to H Perrot.

At least 19 recordsLinked to original sources
PubMed2001

Elaboration and characterization of spatially controlled assemblies of complementary polyphenol oxidase-alkaline phosphatase activities on electrodes.

The electrooxidation of a biotin pyrrole has allowed the formation of biotinylated polypyrrole films. Gravimetric measurements based on a quartz crystal microbalance demonstrate the efficient coupling of avidin, biotinylated polyphenol oxidase (PPO-B) and avidin-labeled alkaline phosphatase (AP-A) with the underlying biotinylated polymer film. The estimated mass increase corresponds to the anchoring of 1.6-1.8 equivalent layer of proteins. A step-by-step construction of bienzyme multilayers composed of PPO-B and AP-A was carried out on the electrode surface modified by the biotinylated polypyrrole film through avidin-biotin bridges. A spatially controlled distribution of the two enzymes was performed by the formation of one AP-A layer on 1, 5, and 10 PPO-B layers. The resulting bienzyme electrodes were applied to the determination of phenyl phosphate on the basis of amperometric detection of enzymically generated o-quinone at -0.2 V. Their analytical performances were analyzed in relation to the design of the enzyme architectures and in comparison with the amperometric behavior of the monoenzymatic electrodes (PPO-B electrode and AP-A electrode). It appears that at the 10-layer-PPO-B polypyrrole electrode only 4% of phenol is transformed, whereas 42-69% of phenyl phosphate is enzymatically consumed and detected at the AP-A polypyrrole electrode, depending on the enzyme activity. For the bienzymatic AP-A/PPO-B polypyrrole electrodes, the activity of each immobilized enzyme clearly affects the biosensor performance, the main limiting factor being the very low efficiency of PPO-B at pH 8.8.

Alkaline Phosphatase↗
PubMed2001

Multiple idiopathic mucocutaneous neuromas: a new entity?

We report a 53-year-old woman who presented with multiple painful red cutaneous papules that had been growing slowly for 13 years. Histopathology showed typical features of neuroma. Biological, morphological and genetic investigations were negative and excluded the diagnosis of multiple endocrine neoplasia type 2b. After reviewing the literature, we concluded that our patient has an extremely unusual acquired disease, which must be considered as a distinct entity in the spectrum of cutaneous neurological disorders.

Diagnosis, Differential↗
PubMed2001

[Role of the hemochromatosis gene in prophyria cutanea tarda. Prospective study of 56 cases].

BACKGROUND: The cause of iron overload in prophyria cutanea tada is unknown. The aim of this work was to determine the frequency of the hemochromatosis gene (HFE) in 56 patients with porphyria cutanea tarda. We analyzed the relationship between HFE mutations and biochemical abnormalities in porphyria cutanea tarda and the interaction with other triggering factors of porphyria cutanea tarda (alcohol abuse, hepatitis C, drugs). PATIENTS AND METHODS: Hepatitis C, alcohol abuse, drug intake and HFE mutations were determined in 56 patients with porphyria cutanea tarda (44 men and 12 women). Iron status was determined from transferrin saturation, serum iron, and serum ferritin. Liver metabolism was determined from liver chemistries: alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase. RESULTS: Thirty-nine patients (69.4 p. 100) carried HFE mutations, 18 (32.1 p. 100) were H63D heterozygous, 4 (7.1 p. 100) were H63D homozygous, 9 (16 p. 100) C282Y heterozygous, 8 (14.2 p. 100) compound C282Y/H63D heterozygous and none were C282Y homozygous. Comparison between porphyria cutanea tarda with and without mutations showed that compound C282Y/H63D heterozygous status was significantly linked to iron overload: transferrin saturation=0.61 vs 0.39 (p=0.0001) and serum iron=32.9 vs 22.4 (p=0.0046). H63D homozygous status was linked to iron overload but non-significantly: transferrin sturatin=0.53 vs 0.39 (p=0.06). The class with high iron overload (transferrin saturation > 0.45) was not linked with triggering factors of porphyria cutanea tarda. Hepatatic cytolysis was linked to alcohol abuse and hepatitis C but not to HFE mutations. DISCUSSION: The frequencies of HFE mutations in Lyons France are halfway between Anglo-Saxon and Italian papers, highlighting the Celtic origin of C282Y mutation. Compound heterozygous and to a lesser degree H63D homozygous status explained the highest iron overload in our patients. This favors clinical expression of porphyria cutanea tarda. This iron overload due to HFE mutations is a new triggering factor of porphyria cutanea tarda independent of classical triggering factors: mutation of the erythrocytic uroporpyrinogen decarbocylase gene, alcohol abuse, hepatitis C, and drugs.

Adult↗
PubMed2000

A new Mr 55,000 surface protein implicated in melanoma progression: association with a metastatic phenotype.

Emergence of the invasive phenotype is a key event in the progression of human melanoma from benign proliferative lesions to malignant lesions. Recently we successfully selected in vivo from a poorly metastatic M4Beu. human melanoma cell line two variants (7GP and T1P26) that generate a higher frequency of spontaneous metastases to the lungs into immune-suppressed neonatal rats. Both cell lines showed no significant differences in the integrin profile of the subunits analyzed except for beta3, which was reduced to a background level in metastatic variants. To investigate how these variant sublines of human melanomas manage to sustain growth in the absence of alpha(v)beta3, a subtractive immunization approach was used to elicit host antibody response against cell surface proteins expressed on metastatic variants. In this study, a new monoclonal antibody (MoAb), LY1, that is highly specific for the 7GP and T1P26 variants, was isolated. LY1 identifies a membrane protein of Mr 55,000 on melanoma variants with epitopes that were resistant to sugar-cleaving enzymes. Immunostaining cells from variants by LY1 showed that staining is distributed to the cell periphery with high labeling intensity at the cell-to-cell contact points. This MoAb significantly inhibited invasion of metastatic variants through a reconstituted basement membrane (Matrigel) in vitro. Moreover, tumor growth of melanoma variants was dramatically affected in vivo with this MoAb. In vitro studies indicate that the LY1 MoAb does not inhibit chemotactic migration of the metastatic variants, the adhesion of tumor cells to vitronectin, collagen IV, fibronectin, and laminin, or cell proliferation. Expression of this antigen is high in human striated muscle, heart, spleen, brain, and lung and absent in kidney, liver, and pancreas. Using 59 fixed, paraffin-embedded archival tissues of human melanomas and nevi, LY1-reactive cells were not observed in melanocytes, nevi, or radial growth phase primary melanomas. In sharp contrast, LY1 selectively stained melanocytes derived from the vertical growth phase of many primary melanomas and metastatic melanomas. These results provide evidence that the Mr 55,000 protein expressed by selected variants with increased metastatic properties in vivo plays a functionally important role in determining metastasis. This molecule may represent a new metastatic risk marker in human melanoma and may be of biological importance in the identification of fatal metastatic subpopulations that have acquired competence for metastasis production.

Animals↗
PubMed2000

Genomic amplification of the human plakophilin 1 gene and detection of a new mutation in ectodermal dysplasia/skin fragility syndrome.

Ectodermal dysplasia/skin fragility syndrome is a recently described autosomal recessive disease affecting skin, nails, and hair (MIM 604536), that results from mutations in plakophilin 1, a structural component of desmosomes. We report a new plakophilin 1 mutation in an affected patient as well as detailing the intron-exon organization of the gene to facilitate future polymerase chain reaction-based mutation screening. Using polymerase chain reaction amplification of genomic DNA, we identified 15 exons spanning approximately 50 kb. Direct sequencing disclosed several nonpathogenic intragenic polymorphisms, as well as a homozygous splice site mutation (1233-2 A-->T; GenBank Z73678) in a 17 y old affected male. The clinical features comprised skin erosions, dystrophic nails, sparse hair, and painful thickening and cracking of palms and soles. Skin biopsy showed negative immunolabeling with an anti-plakophilin 1 antibody and small desmosomes. These results expand the database of plakophilin 1 mutations and demonstrate the importance of this protein in the stabilization of desmosomal adhesion in terminally differentiating keratinocytes.

Adolescent↗
PubMed2000

[Acquired peeling skin syndrome in an adult].

BACKGROUND: Peeling skin syndrome is a rare form of congenital ichthyosis. The term was coined in 1982 by Levy and Goldsmith and the syndrome is clinically characterized by generalized scaling. Histologically, there is an epidermal separation in the stratum corneum. CASE REPORT: We report the case of a 73-year-old woman who had ichthyosis without cicatricial progressive alopecia since her first pregnancy. An ultrastructural study was performed confirming the clinical diagnosis of peeling skin syndrome. DISCUSSION: The peeling skin syndrome designates several different clinical entities classed by Traupe in type A and type B. Mevorah and al. expanded this classification with a type C. This classification has remained valid after additional information provided by ultrastructural studies and may suggest different pathogenic mechanisms underlying the dermatosis. A critical review of the literature shows that the case reported here is exceptional and had a late clinical onset.

Adult↗
PubMed2000

Guess what! SALT - related B-cell lymphoma presenting as a xanthomatous infiltration of the neck.

A 37-year-old man without previous medical history working as a lock keeper was seen in our unit for a progressive painless subcutaneous flesh coloured infiltration of the lower anterior area of the neck growing slowly over 5 months. Clinical cutaneous findings showed a non pruriginous yellowish papulonodular eruption mimicking xanthomas (Figs. 1 and 2). No other clinical abnormalities were found. A cutaneous biopsy specimen was performed. Histopathological examination revealed, under a normal epidermis, a dense lymphoplasmocytoid infiltrate involving the dermis with periadnexal and perivascular reinforcement (Figs. 3 and 4).

Adult↗
PubMed2000

[Chicken pox recurrence revealing a renal adenocarcinoma in an adult].

A new episode of chicken pox in adults who had a well documented infection previously is usually observed in immunocompromised individuals. The principal immunodeficiency factors are hematology diseases, acquired immunodeficiency disease and old age. We report here the case of a young woman who after a contaminating contact presented a recurrence of typical chicken pox. Morphological investigations evidenced a right kidney tumor which pathology revealed to be a renal adenocarcinoma. We discuss this pathological association and review cases reported in the literature.

Acyclovir↗
PubMed1999

A biotinylated conducting polypyrrole for the spatially controlled construction of an amperometric biosensor.

A new biotin derivative functionalized by an electropolymerizable pyrrole group has been synthesized. The electrooxidation of this biotin pyrrole has allowed the formation of biotinylated conducting polypyrrole films in organic electrolyte. Gravimetric measurements based on a quartz crystal microbalance, modified by the biotinylated polymer, revealed an avidin-biotin-specific binding at the interface of polymer-solution. The estimated mass increase corresponded to the anchoring of 1.5 avidin monolayers on the polypyrrole surface. In addition, the subsequent grafting of biotinylated glucose oxidase was corroborated by electrochemical permeation studies. Enzyme multilayers composed of glucose oxidase or polyphenol oxidase were elaborated on the electrode surface modified by the biotinylated polypyrrole film. The amperometric response of the resulting biosensors to glucose or catechol has been studied at +0.6 or -0.2 V vs SCE, respectively.

Biosensing Techniques↗
PubMed1999

Primary cutaneous marginal zone B-cell lymphoma: a report of 9 cases.

BACKGROUND: Primary cutaneous B-cell lymphoma is a heterogeneous group among which marginal zone B-cell lymphoma (MZL) appears to be the most common subtype. OBJECTIVE: We analyze clinical presentation, histologic aspects, and outcome of patients with primary cutaneous MZL. METHODS: All samples classified as primary cutaneous lymphoma over the past 10 years were reviewed, and cases of primary MZL were identified. RESULTS: Nine cases of MZL were analyzed, all from the upper body region, with a predominance in elderly women. Histologic aspects included a dense, nodular, deep-seated infiltrate containing various proportions of small cells displaying a centrocyte-like, plasmacytoid or monocytoid appearance. Surface expression of CD5, CD10, and CD23 was negative. Long survival was noted but relapses in the skin, nodes, orbit, salivary glands, and breast were observed. CONCLUSION: MZL is the predominant primary cutaneous lymphoma of our study. It has distinctive histologic and clinical features as well as outcome.

Female↗
PubMed1999

Linear cutaneous lupus erythematosus in an adult.

We report on a 32-year-old female with a 3-year history of an asymptomatic erythema of the forehead. The lesion had a linear distribution following the lines of Blaschko. Histopathological findings and direct immunofluorescence allowed to establish the diagnosis of cutaneous lupus erythematosus. Treatment with local corticosteroid and antimalarial agents given for 2 months resulted in a complete remission.

Adolescent↗
PubMed1999

[Cutaneous lymphangiectasias acquired after surgical and radiotherapy treatment of breast cancer. Two cases].

We report 2 cases of acquired lymphangiectasias after breast radiosurgical treatment. This well known, rarely reported complication is probably due to a mechanical obstruction of the lymphatic network, and is generally preceded by lymphedema. Our 2 cases, however, did not have previous lymphedema. After a review of the literature, we discuss the role of reparative surgery and other treatment options.

Biopsy↗
PubMed1999

Ulcerated cutaneous epithelioid hemangioendothelioma.

Epithelioid hemangioendothelioma described first by Weiss and Enzinger in 1982 is an uncommon vascular tumor usually involving soft tissue, less frequently the lung and the liver and exceptionally the skin. We herein report a 52-year-old woman who presented an isolated moderately painful persistant ulceration of the concha of her left ear. Histopathological findings showed strands and nests of epithelioid endothelial cells typical of cutaneous epithelioid hemangioendothelioma. Immunohistochemical stainings confirmed the vascular nature of the tumor. Surgical excision by ear amputation was performed. In a review of the literature, to our knowledge, this clinical presentation as ulceration has never previously been reported.

Biopsy, Needle↗
PubMed1998

Validation of antibody-based recognition by piezoelectric transducers through electroacoustic admittance analysis.

The development of immunosensors based on piezoelectric transducers is widely investigated due to their attractive potentialities. The quartz crystal microbalance (QCM) may give a direct response signal which characterizes the binding event between a sensitive layer, immobilized onto the surface transducer, and the analysis to be detected. However, for small biomolecules, such as some antigens, it is quite difficult to obtain an observable signal. This is mainly due to the lack of sensitivity of the commonly used QCM (5 to 10 MHz quartz crystal). Moreover, the mass estimated with the QCM response through the Sauerbrey equation and the mass which can be measured thanks to other analytical techniques, in our case an enzymatic assay, are different: the deposited mass is generally overestimated by the QCM. To validate QCM mass measurements and, therefore antigens recognition, the interactions of acoustic shear waves with a biolayer were investigated during enzyme adsorption onto the microbalance gold electrode or during the antibody/antigen binding. Electroacoustic admittance was measured around the resonance frequency of a 27 MHz quartz resonator in parallel with microbalance measurements. The parameters which characterize the quartz microbalance equivalent circuit were compared with the classical microbalance frequency. The mass overestimation, given by the microbalance, could be explained either by modification of the rheological properties of the sensitive layers and/or by an inadequacy of the assay performed.

Acoustic Impedance Tests↗