PubMed Health⌕ Search

Biomedical subjects

F Cousin

Publications and source records attributed to F Cousin.

At least 19 recordsLinked to original sources
PubMed2004

[Vaccine-induced urticaria: how to differentiate allergy (IgE) from pseudoallergy?].

BACKGROUND: The occurrence of allergic-type manifestations during the course of vaccination is relatively common, and in the majority of cases, these are benign reactions which are also known as "pseudoallergy". They are not immunological in nature and do not activate the effectors of specific immunity. OBJECTIVE: The aim of our work was to propose a practical diagnostic approach following an immediate and/or accelerated post-vaccination accident. PATIENTS AND METHODS: We report our experience in four adults who were referred for urticaria which appeared following vaccination and in two children who were allergic to eggs and were referred for assessment before administration of vaccines containing egg proteins. RESULTS: The immunoallergological examinations (prick-test and intradermal tests with immediate reading) confirmed the absence of immediate hypersensitivity to the vaccine in question and all the patients could be vaccined without incident. CONCLUSION: The majority of post-vaccination reactions with an allergic appearance is benign and do not contra-indicate further vaccination. If there is a suspicion of a true IgE dependent allergy, an immunoallergological investigation will differentiate true allergy from pseudoallergy.

Adolescent↗
PubMed2003

Tuning the interactions of a magnetic colloidal suspension.

We present a versatile experimental system of magnetic charged nanospheres dispersed in water that belongs to both dipolar and electrostatic systems. In this system, the interactions can be continuously tuned by varying the ionic strength I. At low I, the potential is a strongly repulsive Yukawa potential that leads to a phase diagram similar to the one of repulsive spheres (fluid and solid phases). At high I, the potential is a globally attractive Lennard-Jones potential that leads to a phase diagram similar to the one of atomic systems (gas, liquid, fluid, and solid phases).

Journal Article↗
PubMed2003

[Immediate hypersensitivity is rarely implicated in drug induced urticaria].

INTRODUCTION: The unexpected appearance of acute urticaria during the course of drug treatment gives rise to the following question: is it an allergic urticaria (due to an immediate hypersensitivity: IgE mediated specific immunity) or is it pseudo-allergic? We report our findings in an immuno-allergological study of patients who were sent for drug intolerance which presented as immediate hypersensivity (urticaria, angiooedema, anaphylactic shock). METHODS: A prospective study was conducted including all the patients who were sent to the unit for urticaria or angiooedema type drug intolerance. Patients were questioned about previous chronic urticaria and also about urticaria after taking different medicines. The clinical examination looked for a dermographism. All the patients then took skin tests for immediate hypersensitivity, the molecule was contra-indicated and tests for cross-reactivity were conducted. PATIENTS: Three hundred fifty patients were sent to this unit between February 2000 and April 2001 for drug intolerance, mostly with urticaria/angiooedema but in 7 cases with anaphylactic shock. The incriminated drugs were varied: 50 p. 100 were due mainly to penicillins and cephalosporins. Other drug groups were also involved: non steroid anti-inflammatories, aspirin and paracetamol for the most part, along with local anesthetics, morphine-based products, contrast iodine products, corticosteroids. RESULTS: Of the 350 patients tested, only 22 were allergic and had positive tests for the incriminated drug. In these 22 patients, with the exception of 2 of them, the effects were severe (anaphylactic shock in 7 patients) and the urticaria was only a minor manifestation of the reaction. The drugs responsible were cephalosporin (10 patients), the penicillin (6 patients), insulin (2 patients), gonadorelin (1 patient), carboxymethylcellulose (1 patient), lidocain (1 patient), and sulfamethoxazole (1 patient). The 328 other patients had negative tests and were able to retake the tested molecule without incident. Most of them had antecedents of chronic urticaria or dermographism. DISCUSSION: Only 22 patients of the 350, i.e. 6 p. 100 were genuinely allergic. These patients were those who presented the most severe symptoms. The other patients, i.e. the majority, suffered from pseudo-allergic drug-induced urticaria, which made retaking the medicines possible.

Anaphylaxis↗
PubMed2003

[Immunological and non immunological mechanisms in urticaria].

Urticaria involve mast cell activation which could be mediated by immunological or non-immunological mechanisms. Interaction of allergens with the IgE/IgE receptor at the surface of mast cells has been postulated as the main immunologic type of mast cell activation. However, recent experimental and clinical studies have highlighted the existence of other mechanisms involving specific antibodies and T cells. IgG antibodies of different specificities (anti-IgE and/or anti-IgE receptor autoantibodies) have been characterized in a subgroup of patients suffering from chronic "autoimmune" urticaria. Circulating immune complexes may activate mast cells by interaction with the membrane-bound receptor for IgG. Interaction of mast cells with specific T cells could induce mast cell activation. Thus, immune-mediated urticaria appears to be secondary to different types of mast cell activation which could explain the various clinical presentation of the disease.

Arachidonic Acids↗
PubMed2001

Endogenous megakaryocytic colony formation and thrombopoietin sensitivity of megakaryocytic progenitor cells are useful to distinguish between essential thrombocythemia and reactive thrombocytosis.

Diagnosis of essential thrombocythemia (ET) is controversial and remains mainly an exclusion diagnosis. Endogenous megakaryocyte colony (EMC) formation have been largely evaluated to identify specific criteria for ET, but results are impeded by the lack of medium standardization. We evaluated megakaryocyte (MK) colony formation in a serum-free collagen-based medium, without cytokine and in the presence of various concentrations of thrombopoietin (TPO). Thirty-six bone marrows from patients diagnosed with ET (n = 11), polycythemia vera (PV; n = 12), reactive thrombocytosis (RT; n = 6) and healthy donors (n = 7) were assessed. We demonstrate that 11 out 11 of the ET patients had spontaneous megakaryocyte colony-forming unit (CFU-MK) formation, in contrast to none of the RT patients and healthy donors. MK progenitors from ET patients remained responsive to TPO, because exogenous addition of TPO significantly increased cloning efficiency. Moreover, at low doses of TPO (0.5 ng/ml and 5 ng/ml), the number of positive cultures and mean number of TPO stimulated CFU-MK were significantly higher in cultures of cells from patients with ET than in patients with RT. In summary, we have described a standardized serum-free, collagen-based assay that allows differential diagnosis of ET and RT, according to endogenous CFU-MK formation and sensitivity to TPO.

Bone Marrow↗
PubMed2000

Expression of the pro-apoptotic caspase 3/CPP32 in cutaneous basal and squamous cell carcinomas.

Apoptosis, a process of programmed cell death, plays an important role in normal and pathologic tissue homeostasis. The apoptotic cascade is triggered by caspases, a family of cystein proteases, among which caspase 3 (CPP32) seems to be the most directly related to apoptosis. Until now, few, if any, data exist on the role of CPP32 in skin tumors. We studied by immunohistochemistry, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) the expression of CPP32 in specimens of normal human skin, basal and squamous cell carcinomas. CPP32 (both at the protein and mRNA level) was detected within epidermal and adnexal keratinocytes. CPP32 was also expressed in tumor masses of squamous cell carcinomas and more weakly in basal cell carcinomas; no correlation was found between CPP32 expression and depth of tumor invasion. CPP32 was occasionally expressed in tumor-infiltrating lymphocytes and peritumor endothelial cells. The expression of CPP32 in normal skin and in tumors arising from it suggests that this enzyme is involved in their homeostasis; its precise functional significance awaits further investigation.

Blotting, Western↗
PubMed1998

Effects of two sex steroids (17beta estradiol and testosterone) on proliferation and clonal growth of the human monoblastic leukemia cell line, U937.

We investigated the effects of two sex steroids (17beta estradiol and testosterone) on five human leukemia cell lines. We observed a statistically significant inhibition of proliferation, dose and time dependent, of the human monoblastic leukemia cell line U937. This inhibition was associated with a dose dependent decrease in the number of CFU-blasts in clonogenic cultures. Cytostatic effect was obtained with doses of 5 microM for estrogen and 10 microM for androgen and was not due to a non-specific cytotoxic effect, some cell viability remained high (> 90%) even after 6 days of incubation. More accurately, we demonstrated that growth inhibition was associated with a cell cycle arrest, U937 cells accumulating in G2/M phase. This blockade was dose related with a maximum number of cells accumulating at day 4. Sensitivity of these cells to an S-phase specific agent (hydroxyurea) was not increased, suggesting that these cells were blocked in G2/M and did not undergo mitosis. Expression in U937 cells of high affinity nuclear receptors for estrogen and androgen was negative which was in favour of a type II estrogen binding site, mediated mechanism. Moreover, a small fraction of these cells underwent apoptosis or differentiation with about 12% apoptotic cells and a significant increase (more than 30%) of two myelomonocytic markers (CD13 and CD64). These results demonstrate that the proliferation of some leukemic cells may be inhibited by micromolar concentrations of sex steroids, independently of nuclear receptor expression. The main mechanism seems to be a block in cell cycle associated with modulation of apoptosis and differentiation. It provided additional evidence for the potential value of sex steroids and their analogues in the treatment of leukemias.

Apoptosis↗
PubMed1998

Use of collagen for standardization of PBSC graft quality evaluation: a multicenter comparative analysis of commercial collagen-based and methylcellulose-based colony-forming unit (CFU) assay kits.

The colony-forming unit-granulocyte-macrophage (CFU-GM) assay, an essential test in evaluation of the quality of autologous grafts of hematopoietic stem cells, has yet to be standardized. With this aim in view, we carried out a multicenter study of five commercially available culture kits for CFU-GM evaluation. Four kits were methylcellulose-based (H4431, H4434, H4435, StemBio1d) and one was collagen-based (EasyClone-Multi). Using fresh and frozen samples of PBSC grafts, we compared CFU-GM and burst-forming unit-erythrocytes (BFU-E) growth using the EasyClone kit to each of the methylcellulose kits. BFU-E and CFU-GM clonogenicity of both fresh and frozen PBSC was clearly inferior with the H4431 kit, which provides conditioned medium only. CFU-GM numbers obtained with fresh and frozen PBSC samples were significantly higher with the EasyClone kit than with the H4434 and StemBio kits. BFU-E numbers were also higher with the EasyClone kit, but only when colonies were scored after May-Grünwald-Giemsa (MGG) staining. Finally, although the H4435 kit provides higher doses of recombinant cytokines than the EasyClone kit, CFU-GM and BFU-E numbers obtained for fresh or frozen PBSC with both kits were similar. In addition, CFU-GM and BFU-E numbers correlated well with CD34+ cell numbers for all five kits for both fresh and frozen PBSC. In summary, our study shows that the EasyClone-Multi and H4435 kits provide the best CFU-GM growth. The collagen-based EasyClone kit has the additional advantage of allowing gel staining and storage, which facilitates colony identification and, more importantly, makes gel exchange possible for standardization of the CFU-GM assay.

Adolescent↗
PubMed1998

[Melkersson-Rosenthal syndrome].

Melkersson-Rosenthal syndrome is a rare entity and is, in its complete presentation, characterized by the association of recurrent orofacial swelling, peripheral facial palsy and plicated tongue. Clinical diagnosis of incomplete forms, frequently described, is based on major and minor features, currently accepted by numerous clinicians. For most investigators, Miescher's granulomatous macrocheilitis is a monosymptomatic form of the affection. Histopathological findings reveal non-caseating epithelioid cell granulomas, with sometimes perivascular pathognomnic arrangement, which typically shows an obliterant epithelioid lymphangitis. The etiology of the disorder is unknown; a possible association with Crohn's disease has been proposed. Local or general corticosteroids therapy is usually proposed possibly with a cheiloplastic procedure.

Diagnosis, Differential↗
PubMed1987

[Myelofibrosis. Pathology of the microenvironment].

Myelofibrosis is the most representative model of the association between the hemopoiesis failure end the abnormalities of the myeloid microenvironment. Long term culture in Dexter's liquid system is a good model for the in vitro study of myeloid differentiation. An experimental in vitro system using an irradiated under layer and aplastic patients plasma has yielded some preliminary results allowing the production of megakaryocytic colonies. Close contact between these colonies and the fibroblasts or stromal cells in the adherent layer could probably be used for the study of the interrelation between the stromal abnormalities and myeloid pathology.

Hematopoietic Stem Cells↗
PubMed1984

[Caloric value of food and coverage of the recommended nutritional intake of vitamins in the adult human. Principle foods containing vitamins].

Two daily food consumption models were defined. One of them (I) is representative of the French eating habits, the other (E) of a diet with a theoretically balanced content of macronutrients for a caloric intake of 2,500 kcal. For each of these two models, four menus were calculated to obtain four caloric levels (1,500, 2,000, 2,500 and 3,000 kcal). The vitamin content of these menus was established on the basis of the literature (food composition tables). Nutritional losses resulting from usual cooking methods were taken into account. The results show that the dietary intake of some vitamins, such as folic acid, pantothenic acid, vitamin A, beta-carotene, vitamin C and B1, was likely to be inadequate and are in agreement with those of epidemiologic surveys carried out in developed countries. The threshold of 80% of the recommended allowances is not reached with a caloric level of 2,500 kcal (balanced diet) or 2,700 kcal (unbalanced diet). For an allowance of 1,500 kcal, most of the vitamins do not reach or just reach 50% of the recommended level. This result shows that the former eating habits of the French population, whose caloric intake was high (more than 3,000 kcal), were correct as they covered the recommended intakes of micronutrients. This work corroborates the great importance of some food groups in covering the recommended vitamin intakes and underlines the necessity of diversifying food.

Adult↗
PubMed1982

Platelet arachidonic acid metabolism in severe cerebrovascular disease.

The ability of platelets to synthetise thromboxane B2 and hydroxylated fatty acids from arachidonic acid was studied simultaneously with arachidonic acid-induced aggregation in 42 patients suffering from severe cerebral atherosclerosis and also in 34 healthy controls. Additionally, phospholipase-A2-induced aggregation was performed as a probe for arachidonic acid located at the platelet surface. All the assays were performed with washed platelets, eliminating a possible influence of plasma. Platelets from patients were found responsive to significantly lower concentrations of arachidonic acid whereas thromboxane and hydroxylated fatty acid biosynthesis did not differ from controls. In the experimental conditions used, 75% of the control platelets underwent aggregation with phospholipase A2 plus sphingomyelinase C, in comparison to only 50% for the patients, indicating the necessity for further analysis of the platelet membrane lipids in atherosclerosis.

Adult↗
PubMed1980

[Limits of platelet aggregation tests for investigating thromboses (author's transl)].

Three methods--spontaneous aggregation, ADP-induced aggregation and levels of circulating platelet aggregates--were used to test for platelet hyperaggregation in 87 adult patients divided into three groups. Group A comprised 26 patients with severe arterial diseases, including cerebral vascular accidents (16) and peripheral thrombosis (10) ; group B consisted of 31 patients with venous conditions, including deep phlebitis (22) and recurrent thrombo-embolic disease (9) ; group C, which served as control, comprised 30 patients with various non-vascular disorders. Spontaneous aggregation and enhanced reactivity to ADP correlated well with each other and were more frequent in patients with vascular diseases. However, one-third of patients in group C had pathological results, while one-third of patients in groups A and B had normal results, independently of any clinical particularity or therapeutic regimen. There were no significant differences between the three groups with regard to circulating platelet aggregates. These tests, therefore, appear to be of statistical and epidemiological interest, but of questionable practical value.

Adenosine Diphosphate↗