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Biomedical subjects

D Leroy

Publications and source records attributed to D Leroy.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Cutaneous localization of T-cell prolymphocytic leukemia].

INTRODUCTION: T cell prolymphocytic leukemia (T PLL) is a rare variant of mature lympho-proliferative disorder. The main physical sign is a gross splenic enlargement contrasting with no enlargement of lymph nodes. Skin involvement is found in 30 p. 100 cases. Twenty-one cases of cutaneous lesions of PLL have been reported, mainly with T PLL, only 2 cases of B PLL: Clinical lesions are polymorphous; histology shows a dermal prolymphocytic infiltrate. The main cytogenetic abnormalities are: translocation (14; 14) (q11; q32), inversion of chromosome 14 (q11; q32), isochromosome 8q. CASE REPORT: We report a case of an 87-year-old patient presenting a T cell prolymphocytic leukemia CD4+ with specific papular lesions of the back. Electron microscopy showed typical prolymphocytes and cytogenetic studies showed a tendency to polyploidy, with the lost of chromosome 14, translocation 8-22 and inversion of chromosome 13. After 12 months of treatment with a combination of chloraminophen and prednisone the patient was in partial remission and the cutaneous lesions disappeared. DISCUSSION: This case is rare and the patient has an unusual long survival (mean survival is 7 months). Contrary to the other hematologic disorders, cutaneous involvement does not change the prognosis of T PLL:

Aged↗
PubMed1995

[Cryptococcal whitlow in a HIV positive patient].

INTRODUCTION: Cutaneous cryptococcosis is a systemic fungal disease; it is commonly observed in immunocompromised patients. OBSERVATION: We report the case of a cryptococcal whitlow in an HIV positive patient. The mycologic culture of the cutaneous lesion was positive for Cryptococcus neoformans serotype D. The detection of the blood antigen was positive but there was no pulmonary nor central nervous system involvement. The lesions cured with fluconazole (400 mg/day during 2 months and 200 mg/day after). DISCUSSION: This unusual clinical presentation of cutaneous cryptococcosis has never been reported in an HIV positive patient. As the dermatologic manifestations of cryptococcosis are polymorphous mycologic examination of skin lesions is very important.

Aged↗
PubMed1994

Characterization of an active GST-human Cdc2 fusion protein kinase expressed in the fission yeast Schizosaccharomyces pombe: a new approach to the study of cell cycle control proteins.

Characterization of cdk (cyclin dependent kinases) substrates and studies of their regulation require purified enzymatic complexes of cdc2-related catalytic and cyclin regulatory subunits. We produced human Cdc2 kinase in the fission yeast Schizosaccharomyces pombe as a fusion protein with glutathione S-transferase (GST). The GST-human Cdc2p fusion protein was active in vivo since it rescued a temperature-sensitive allele of cdc2. The fusion protein was purified using a one-step chromatography procedure with glutathione-Sepharose and exhibited a catalytic activity in vitro. Yeast cyclin B and suc1 were found in association with GST-Cdc2. A 17-fold stimulation of GST-Cdc2 kinase activity was obtained by incubation of recombinant human cyclin A with the S. pombe cellular extract prior to affinity purification. This indicates that cyclin concentration is limiting in this overexpression system. These findings describe a fast and easy production of active recombinant human Cdc2 kinase in yeast that can be used for biochemical studies.

CDC2 Protein Kinase↗
PubMed1994

Contact dermatitis from a textile flame retardant.

We report a case of contact sensitivity to Flammentin ASN, a flame retardant used on cotton and wool. The patient was a painter who was protecting his face with a white cotton cap. He presented with eczema of the forehead at the sites of cap contact. Patch tests with the treated cap and flame retardant were positive; a formaldehyde patch test was negative. Flame retardants are used in construction, materials and textiles. Contact sensitivity is rarely described and we compare our case to those published in the literature.

Adult↗
PubMed1994

Modulation of the molecular organization and activity of casein kinase 2 by naturally occurring polyamines.

Polyamines have been reported to stimulate casein kinase 2 (CK2) in vitro. We have shown that the phosphorylation of different substrates is diversely stimulated by basic effectors and that the responsiveness of CK2 activity may be influenced by the overall conformation of the protein substrate but also by a specific interaction with the enzyme itself. Our data show that native hetero tetrameric CK2 is a spermine binding protein and a spermine binding site was identified in the N-terminal region of the beta subunit of CK2. We found that recombinant CK2 undergoes a progressive polymerization in low salt conditions, giving rise to three different polymer structures. A ring-like structure formed by the association of four protomers alpha 2 beta 2 was characterized by gel filtration, sucrose density gradient analysis and electron microscopy. Polyamines like spermine, when added under conditions where the enzyme preparation contains a mixture of various oligomers, could trigger their dissociation and their interconversion in the fully active ring structure. These results suggest that in the presence of positive effectors like polyamines, CK2 adopts a ring-like structural organization which may represent the active state of this kinase.

Amino Acid Sequence↗
PubMed1994

Photocontact allergy to oxybenzone: ten years of experience.

Intolerance of sunscreen agents has often been reported in the literature. This mainly comprises photosensitization to sunscreens such as oxybenzone. The aims of this study were to establish the incidence of photocontact allergy to oxybenzone and its relationship with the use of other cosmetics. From 1982 to 1992 we performed photopatch tests on 283 patients with suspected photodermatosis. Forty-six patients (16%) had positive reactions: 61 positive photopatch tests and 9 positive patch tests. Photocontact allergy to sunscreens was divided into 2 main groups: 35 cases to oxybenzone and 17 cases to para-aminobenzoic acid and its derivatives. Among our 35 cases of photoallergy to oxybenzone, more than one third had photoallergy to a daily moisturizer that contained oxybenzone.

4-Aminobenzoic Acid↗
PubMed1994

Contact photosensitivity to nonoxynol used in antiseptic preparations.

Nonoxynols are nonionic surface-active agents used as surfactant in numerous cosmetic products and antiseptic preparations. Recently nonoxynol contact allergy has been described. We report two patients who presented a contact photosensitivity to nonoxynol 10 contained in Hexomédine transcutanée. Among 32 control subjects, we found 13 positive photopatch tests to Hexomédine transcutanée and 4 positive photopatch tests to nonoxynol 10. Surprisingly, the authors observed that only undiluted nonoxynol was phototoxic.

Administration, Cutaneous↗
PubMed1994

Dissimilar alterations of sodium-coupled uptake by platinum-coordination complexes in renal proximal tubular cells in primary culture.

The potent anticancer drug cis-diamminedichloroplatinum (II) (CDDP) interferes early with electrolyte transport by the renal proximal tubule. To study the early effects of platinum coordination complexes on apical Na(+)-coupled transport systems, we examined the effect of increasing concentrations of CDDP, trans-diamminedichloroplatinum (II) (TDDP) and cis-diammine-1,1-cyclobutane-dicarboxylate platinum (II) (CBDCA) on Na(+)-coupled uptake of P(i), methyl-alpha-D-glucopyranoside (MGP) and L-alanine by rabbit proximal tubule cells in primary culture. At 17 microM CDDP and 540 microM CBDCA, 1) cell viability (lactate dehydrogenase release) and ATP content were unaffected, 2) Na(+)-K(+)-ATPase activity was reduced by 40%, 3) Na(+)-coupled uptake of MGP and P(i) was reduced, whereas 4) Na(+)-coupled uptake of alanine rose to twice the control value. Alterations of Na(+)-coupled uptake of P(i), MGP and alanine were due to changes in Km, with no significant change in Vmax. At 333 microM TDDP, Na(+)-dependent P(i) and MGP uptake decreased, whereas Na(+)-independent uptake increased markedly and was associated with a decline in cell viability and ATP content. We conclude that 1) the TDDP-induced decrease in Na+/P(i) and Na+/glucose cotransport was associated with reduced cell viability, 2) both CDDP and CBDCA had different effects on Na+/P(i), Na+/glucose and Na+/alanine cotransport, arguing against an alteration of the Na+ gradient due to reduced Na(+)-K(+)-ATPase activity and 3) CBDCA induced alterations of Na(+)-coupled uptake similar to those of CDDP at concentrations 20 to 30 times higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1994

A new human mtDNA polymorphism: tRNA(Gln)/4336 (T-->C).

We report the observation of a polymorphism in the human mitochondrial tRNA(Gln) gene. This polymorphism is detectable by both NlaIII and Sau961, whose recognition sequences overlap at the polymorphic base pair.

Base Sequence↗
PubMed1994

[Squamous cell carcinoma and disseminated superficial actinic porokeratosis].

Disseminated superficial actinic porokeratosis was first described by Chernosky and Anderson in 1969. It is characterized by multiple small keratotic lesions on sun-exposed areas beginning in the third of fourth decade. The development of a squamous cell carcinoma within lesions of porokeratosis or the association of superficial actinic porokeratosis with immunosuppression have been well documented. We report the case of a 68-year-old patient who presented actinic porokeratosis associated with rapidly evolutive squamous cell carcinoma of the leg. During the hospitalization, an IgA myeloma was discovered. The authors discuss the relationship between porokeratosis, immunosuppression, and squamous cell carcinoma. Pathogenesis of the lesions is interesting because it is admitted that a keratinocyte clone which carries the porokeratosis abnormality is going to proliferate because of immunosuppression, trauma and infectious diseases. It seems important to search for immunosuppression in patients presenting porokeratosis because the incidence of malignant transformation may increase.

Aged↗
PubMed1993

Effect of glucose and insulin deprivation on differentiation and carbohydrate metabolism of rabbit proximal tubular cells in primary culture.

Rabbit proximal tubule cells in primary culture revert from gluconeogenesis to glycolysis. To determine whether glucose and insulin deprivation of the culture medium could prevent this metabolic conversion without a loss of differentiation, rabbit proximal tubule cells were cultured in hormonally defined medium free of glucose and insulin and compared to rabbit proximal tubule cells cultured in medium supplemented with 17.5 mM glucose and 5 micrograms/ml insulin. In the two culture conditions, RPT cells grew at a similar rate and reached confluency within 4-5 days. Patterns of enzyme activity, including brush-border hydrolases, N-acetyl-beta-D-glucosaminidase and glutathione-S-transferases as a function of culture time were comparable in the two media. During the growth phase in glucose- and insulin-free medium, cells showed higher sodium-dependent glucose uptake. Scanning electron microscopy revealed a high density of microvilli at confluency regardless of the culture conditions. In both the presence and absence of glucose and insulin, the activities of gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase, as well as basal and pyruvate-stimulated glucose production fell markedly as a function of time. By contrast, glucose and insulin deprivation greatly reduced both the lactate production rate and the activities of glycolytic enzymes, pyruvate kinase, hexokinase and lactate dehydrogenase.

Acetylglucosaminidase↗
PubMed1993

Platinum complex-induced dysfunction of cultured renal proximal tubule cells. A comparative study of carboplatin and transplatin with cisplatin.

Platinum coordination complexes (PtCx) are potent against several types of cancer but are often nephrotoxic. With a view to developing a PtCx nephrotoxicity model, the toxicity of cisplatin (cDDP), transplatin (tDDP) and carboplatin (CBDCA) was studied in primary cultures of rabbit proximal tubule (RPT) cells and in the renal epithelial OK cell line. The cytotoxicity of these PtCx (10-3000 microM) was assessed after 24 h exposure of confluent monolayers in terms of LDH release; their effects at non-cytotoxic concentrations (1-1000 microM) on DNA and protein synthesis, glucose transport, marker enzymes and the total glutathione concentration were also determined, together with cellular platinum uptakes. The cytotoxicity ranking of the studied compounds differed for OK and RPT cells (cDDP > tDDP; cDDP > CBDCA and tDDP > cDDP; cDDP > CBDCA, respectively). Only results which were obtained in RPT cells corresponded to reported nephrotoxicity in vivo, making OK cells inappropriate for the study of PtCx nephrotoxicity in vitro. cDDP was about 10 times less cytotoxic for OK cells than for RPT cells because of lower cellular uptake. tDDP was unable markedly to inhibit biochemical and functional parameters in RPT cells below cytotoxic concentrations. At non-cytotoxic concentrations, cDDP and CBDCA depressed synthetic activity (mainly DNA) and, to a lesser extent, Na(+)-K(+)-ATPase activity and glucose transport in RPT cells. Total glutathione levels in RPT cells steadily increased during exposure to cDDP, tDDP and CBDCA, before the onset of cell death, arguing against an early role of glutathione depletion in PtCx toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Acral erythema after allogeneic graft of the bone marrow].

Acral erythema (AE) is a painful, erythematous bullous eruption of the palms and soles which is chemotherapy-induced. To the numerous chemotherapies which induce AE we must add, perhaps, a new drug, Vépéside. AE is followed by graft-versus-host-disease in all patients receiving bone marrow transplantation. AE and early GVH disease being very similar, we discuss the differential diagnosis which can be very difficult.

Acrodermatitis↗