PubMed Health⌕ Search

Biomedical subjects

V Callot

Publications and source records attributed to V Callot.

11 recordsLinked to original sources
PubMed2000

Dynamic imaging of hyperpolarized (3)He distribution in rat lungs using interleaved-spiral scans.

The use of spiral scan techniques is investigated for (3)He lung imaging on small animals. Dynamic series of up to 40 high temporal resolution (3)He ventilation images are obtained using a single bolus of gas. General properties of the spiral technique are discussed and compared to those of standard imaging techniques in relation to the specific case of rare gas imaging. To improve temporal resolution of the image series, the efficiency of a sliding window technique, combining data from two consecutive spiral images, is demonstrated. An example of the typical global (3)He signal variation during the (3)He breathing of the animal is shown. Pixel-by-pixel measurements of the (3)He signal derivative during the gas inspiration are performed. A corresponding lung map of the magnetization per time unit entering the lung during gas inflow is presented.

Animals↗
PubMed2000

Laser-polarized (3)He as a probe for dynamic regional measurements of lung perfusion and ventilation using magnetic resonance imaging.

Magnetic resonance imaging (MRI) using laser-polarized noble gases, such as (129)Xe and (3)He, allows unparalleled noninvasive information on gas distribution in lung airways and distal spaces. In addition to pulmonary ventilation, lung perfusion assessment is crucial for proper diagnosis of pathological conditions, such as pulmonary embolism. Magnetic resonance perfusion imaging usually can be performed using techniques based on the detection of water protons in tissues. However, lung proton imaging is extremely difficult due to the low proton density and the magnetically inhomogeneous structure of the lung parenchyma. Here we show that laser-polarized (3)He can be used as a noninvasive probe to image, in a single MRI experiment, not only the ventilation but also the perfusion state of the lungs. Blood volume maps of the lungs were generated based on the (3)He signal depletion during the first pass of a superparamagnetic contrast agent bolus. The combined and simultaneous lung ventilation and perfusion assessments are demonstrated in normal rat lungs and are applied to an experimental animal model of pulmonary embolism. Magn Reson Med 44:1-4, 2000.

Animals↗
PubMed2000

Olmsted syndrome: report of two new cases and literature review.

Olmsted syndrome is a rare keratinization disorder; 18 cases have been published so far. It associates a mutilating cogenital palmoplantar keratoderma with periorificial erythematokeratotic lesions. We report herein two new unrelated male children with Olmsted syndrome (OS), one of whom was studied by light and electron microscopy. Our histological, immunohistochemical, and ultrastructural findings suggest that this disease is related to epidermal hyperproliferation. We present herein a review of the twenty cases published so far and discuss the major clinicopathological and genetic features of this disease.

Child↗
PubMed1996

[Histiocytosis].

Histiocytic disorders are a group of heterogeneous diseases. A logical classification can be based on the type of proliferating cell, either monocyte-macrophage or Langerhans/dendritic cell, and depends whether the proliferating cells are "reactive" or malignant. The classification now mainly depends on the histological examination. Regarding Langerhans cell histiocytosis (Hand-Schüller-Christian disease, Letterer-Siwe disease and eosinophilic granuloma), the diagnosis suspected on various clinical signs, is confirmed with histological examination showing infiltration with CD1 positive histiocytes disclosing intracytoplasmic Birbeck granules at electron microscopic examination. The prognosis depends on the patient's age at onset and the extension of the disease. Treatment is based on chemotherapy and corticotherapy.

Histiocytosis↗
PubMed1996

Drug-induced pseudolymphoma and hypersensitivity syndrome. Two different clinical entities.

OBJECTIVE: To test the hypothesis that drug-induced pseudolymphoma and hypersensitivity syndrome are 2 distinct clinical entities. DESIGN: Retrospective study from 1980 to 1993. SETTING: Departments of dermatology and medicine of 5 referral universitary hospitals. PATIENTS: Twenty-four patients who met arbitrary criteria selected as being suggestive of lymphoma, with probable drug cause. Patients with other definite cutaneous drug-induced eruptions were excluded. INTERVENTION: None. MAIN OUTCOME MEASURES: Suspect drugs; clinical, biological, and pathological findings; and evolution of each case and of 110 published case reports. RESULTS: Two groups were separated according to their mode of onset and clinical aspect. Three patients (and 15 cases in the literature) had subacute papulonodular or infiltrated plaques, without visceral involvement. Skin biopsy specimens showed a dense lymphocytic infiltrate mimicking lymphoma. Healing was constant when the drug was stopped. The 21 remaining patients (and 95 published cases) had an acute widespread eruption, with fever, enlarged lymph nodes, and multivisceral involvement. Lymphocytosis, atypical lymphocytes, eosinophilia, hepatitis, and high levels of lactate dehydrogenase were frequent. Skin biopsy findings were usually not specific (lymphocytic infiltrate and keratinocyte necrosis) but sometimes mimicked lymphoma. Severe forms and relapses occurred, even after the drug was stopped. The inducing drugs were the same in the 2 groups. CONCLUSIONS: These 2 groups correspond to drug-induced pseudolymphoma and hypersensitivity syndrome. We think that they are 2 distinct entities with different clinical and biological features and outcome, even if the pathological findings are sometimes similar. Prospective studies are needed to confirm these facts, to evaluate the therapy, and to follow up patients.

Adolescent↗
PubMed1995

Pachydermodactyly and atrophia maculosa varioliformis cutis.

Pachydermodactyly is a rare form of superficial digital fibromatosis characterized by progressive asymptomatic thickening of the back and sides of the proximal interphalangeal joints of the fingers. Atrophia maculosa varioliformis cutis is an acquired dermal atrophy, localized on the cheeks. Only a few cases of each pathology have been published. We find it interesting to report the case of a patient with both conditions as these two connective-tissue diseases are very rare. The association is probably fortuitous.

Adult↗
PubMed1994

[Pemphigus].

Pemphigus is a rare autoimmune bullous disease of the skin and mucosae. It has predisposing genetic factors and, in the case of pemphigus foliaceus, environmental factors; some therapeutic drugs may trigger off pemphigus. The disease often begins with painful buccal erosions, followed by flaccid bullae on healthy skin. Some lesions are erythematous plaques involving the seborrheic areas. Cytology shows acantholysis and histology, intraepidermal cleavage. Direct immunofluorescence confirms the diagnosis by showing a network deposit of immunoglobulins and complement. The titres of circulating antibodies to the intracellular substance vary with the course of the disease. The loss of cohesion between keratinocytes is induced by autoantibodies directed against antigens of the epidermal cell junction zone; the molecular weight of these antibodies is 130 and 85 kD for pemphigus vulgaris and 160 and 85 for superficial pemphigus. Paraneoplastic pemphigus is a recently individualized entity. Treatment consists of systematic corticosteroid therapy, sometimes associated with immunosuppressants; it has improved the prognosis of this once lethal disease.

Humans↗
PubMed1994

[Acute arthritis during isotretinoin treatment].

We report a case of acute arthritis of the knee which occurred in a dose-dependent manner during treatment with isotretinoin. Recurrence was seen at rechallenge. Only three observations of acute arthritis induced by isotretinoin have been reported in the literature. This side effect is rare and does not require drug withdrawal but rather an adapted dose.

Acne Vulgaris↗