Search PubMed⌕ Search

Biomedical subjects

A Moreau

Publications and source records attributed to A Moreau.

At least 109 records · Page 6Linked to original sources

[Histopathologic features of cytomegalovirus lymphadenitis in the "immunocompetent" patient. Report of 7 cases].

The authors report seven cases of cytomegalovirus lymphadenitis in apparently immunocompetent patients. One patient presented with an infectious mononucleosis-like illness. The main presentation of the others was isolated cervical lymphadenopathies. The lymph node pathology showed aspecific lymphoid hyperplasia, resembling the human immunodeficiency virus related lymphadenopathy, associated with diagnostic inclusion cells. Infected cells were confined to areas of monocytoid B cell hyperplasia in all cases whereas exceptionally observed in germinal centers. Because of their variable appearance, serial sectioning was frequently necessary to disclose their characteristic features. In all cases, immunohistochemistry using an anti-cytomegalovirus antibody was positive and revealed more infected cells than detected by morphology alone. Except for the endothelial cell, the nature of infected cells remained undetermined. An alteration of the antigenic expression as a consequence of cell infection might be responsible for immunohistochemistry failure in the cell characterization.

Adult↗

Late acute failure of well-HLA-matched renal allografts with capillary congestion and arteriolar thrombi.

Seventeen cases of a histologically and clinically unusual renal acute dysfunction in kidney recipients, individualized among a population of 1378, are reported. The basic histological lesion was a huge capillary congestion, associated with capillary and arteriolar thromboses or parenchymal necrosis in most patients, and contrasting with the absence of the classical features of acute cellular rejection, i.e., tubulitis, glomerulitis, edema, and infiltrate. The corresponding clinical history was characterized by its early timing in the course of transplantation (< 3 months), its sudden occurrence in patients usually having good transplant function, leading to end-stage renal failure in a few days, and its resolution under rejection treatment. The occurrence of this syndrome was significantly linked with a good HLA matching: 13 of the 17 recipients were HLA-DR matched (P < 0.0001). The etiology of this syndrome remains unknown. There was no evidence for graft vessel thrombosis. Because of some histological similarities, the usual causes of the hemolytic uremic syndrome, including bacterial and viral infections or cyclosporine arteriolopathy, were discussed. Acute vascular rejection was suspected, but the cross-match was negative on T lymphocytes in all cases and anti-HLA class I and II antibodies were not found to develop at the time of transplant dysfunction, except in 1 patient, in whom the detected anti-DR antibodies were not directed at the kidney donor. Anti-human umbilical vein endothelial cell antibodies, detected in an antibody-dependent cellular cytotoxicity assay, were present in 6 patients (of the 14 tested) at the onset of renal failure, but they were either absent (n = 3) or already present at the time of transplantation (n = 5) in the other 8 patients. Therefore, reliable arguments are lacking to conclude that this acute transplant dysfunction is an acute vascular rejection and its strong association with HLA matching has, as yet, no satisfactory explanation.

Acute Disease↗

High dose radiochemotherapy followed by autologous stem cell transplantation in four patients with multiple lymphomatous polyposis.

BACKGROUND: Multiple lymphomatous polyposis (MLP) results from gastrointestinal involvement by a B-cell lymphoma that originates from the mantle zone of lymphoid follicles. This well described clinicopathologic entity has a poor prognosis: the rate of complete response after conventional chemotherapy is very low. High dose radiochemotherapy with autologous stem cell transplantation (ASCT), which is one of the most intensive treatments of lymphoma, to the authors' knowledge has not been evaluated in the treatment of MLP. METHODS: Four consecutive patients with MLP were treated with high dose radiochemotherapy and ASCT while they were in partial response after conventional chemotherapy. RESULTS: Three patients achieved a complete clinical and histologic response and one achieved a complete clinical resolution of symptoms, but with persistent histologic lesions. Progression free survival ranged from 11 to 35 months. CONCLUSIONS: Autologous stem cell transplantation for patients with MLP is feasible and may be more effective than conventional chemotherapy. However, further studies are needed to assess the actual place of this type of treatment in the management of MLP.

Adult↗

Selective lysis of autologous tumor cells by recurrent gamma delta tumor-infiltrating lymphocytes from renal carcinoma.

We show here that tumor infiltrating lymphocytes (TIL) derived from three renal carcinoma (RC) tumors, which developed in the same patient over a 3-yr period, were systematically enriched in gamma delta + T cells (27-74%) after short term in vitro culture. Analysis of the repertoire of gamma delta + TIL and PBL from this patient, revealed the predominant expression of structurally diverse V delta 1 gamma delta TCR by TIL from the three tumors, contrasting with the classically dominant use of V delta 2 TCR by PBL. Functional analysis further showed that, independently of the V gamma genes expressed, all the V delta 1+ TIL clones exhibited a lytic activity apparently restricted to RC lines, while V gamma 9+V delta 2+ clones (either PBL- or TIL-derived) had a broad killing activity. Surprisingly most V delta 1+ CTL clones lysed several allogeneic, but not the autologous, RC lines. Only one V gamma 3+V delta 1+ TIL clone, identified by its specific variable TCR gene sequence, consistently killed autologous tumor cells, apparently via TCR-mediated MHC-unrestricted recognition. This clone also lysed two allogeneic RC lines out of four tested but did not kill 30 non-RC lines, except for one breast carcinoma line. Significantly, this clone was found in recurrent fashion in all three tumors analyzed, including a metastasis. The high frequency of V delta 1 expressing RC-reactive gamma delta cells among TIL from this patient suggests that this gamma delta subset was selectively trapped and/or preferentially induced to proliferate in the autologous tumors. The recurrence of a single V gamma 3+V delta 1+ gamma delta clone, reacting with autologous tumor cells, inside three tumors of different localizations additionally suggests that, for this clone, intratumor selection and/or proliferation was due to TCR-mediated recognition of a non-MHC-restricted RC-specific Ag.

Adolescent↗

Deletion cartography around the D13S25 locus in B cell chronic lymphocytic leukemia and accurate mapping of the involved tumor suppressor gene.

The presence of an unidentified tumor suppressor gene on the long arm of chromosome 13 which could be involved in the development of B cell chronic lymphocytic leukemia has been suspected because of frequent deletions of the locus D13S25 which lies 1.6 cM telomeric to the retinoblastoma gene. In order to accurately map this gene, cells from 25 B cell chronic lymphocytic leukemia tumors have been analyzed for allelic loss using a panel of microsatellite markers located in this region. These markers, which stretch from the retinoblastoma gene to the Wilson disease gene, have been ordered for their rank from centromere to telomere. In addition to the data obtained from deletion pattern of these markers, results from preliminary pulse-field electrophoresis studies enable us to redefine the minimal deleted area from more than 1 cM to 280 kilobase around D13S25.

Chromosome Deletion↗

Distribution of albumin, alpha 1-inhibitor 3 and their respective mRNAs in periportal and perivenous rat hepatocytes isolated by the digitonin-collagenase technique.

The expression of albumin and alpha 1-inhibitor 3 genes was investigated in rat cell suspensions enriched in periportal (n = 10) and perivenous (n = 10) hepatocytes obtained by the digitonin-collagenase technique. The degree of enrichment of the cell suspensions was assessed: (1) by enzymic assays for the periportal marker alanine aminotransferase and for the perivenous marker glutamine synthetase; and (2) by their content of mRNAs for the periportal marker hepatic glutaminase and for glutamine synthetase. The existence of an antegrade intra-lobular gradient for albumin and alpha 1-inhibitor 3 mRNAs was demonstrated, with periportal:perivenous ratios of 2.33 and 3.80, respectively. However, no gradient was demonstrated for the respective protein contents with corresponding ratios of 0.98 and 1.21. A certain degree of overlap existed between periportal and perivenous suspensions for their content in albumin and alpha 1-inhibitor 3 mRNAs. A morphometrical analysis of the surface of digitonin-permeabilized hepatic tissue revealed that this overlap could be explained by a variable extent of permeabilization of the mediolobular zone from one rat to another and from one lobule to another in a given animal. These results suggest that while the digitonin-collagenase technique is well suited for studies in vitro of proteins expressed in sharp intra-lobular gradients or restricted to an intra-lobular compartment, it is not completely reliable for proteins distributed in continuous moderate intra-lobular gradients, such as albumin and alpha 1-inhibitor 3.

Acute-Phase Proteins↗

Captopril and aspirin in treatment of renal microangiopathy in primary antiphospholipid syndrome.

Treatment of antiphospholipid syndrome (APS) is controversial. We report a case of renal microangiopathy in a 40-year-old woman with APS. The nephropathy was isolated without signs of disseminated thrombotic microangiopathy or progressive systemic sclerosis. Similarities with sclerodermatous kidney and an increase in plasma renin activity led us to initiate treatment with aspirin and captopril, with excellent control of the renal syndrome. We believe this therapeutic regimen may be an effective means of treating the renal microangiopathy of APS.

Adult↗

Phototoxic and photoprotective effects of topical isothipendyl.

Isothipendyl, an H1-receptor antagonist, is an antihistamine used as an antiallergic drug. Its molecular structure is close to the phenothiazines, but it has different photobiological properties. Like phenothiazines, isothipendyl is phototoxic with ultraviolet A (UVA) but it reduces the erythema response to UVB radiation. Isothipenyl seems to have the same protective properties as a sunscreen because its UVB protective properties are effective only if the substance is applied prior to exposure.

Anti-Allergic Agents↗

[Identification of spermatozoa L-selectin and two potential pellucida ligands].

At the molecular level, gamete interactions partly depend on zona pellucida-glycoproteins fucosylation. We show, by immunocytochemistry, the sialyl-lewisx and sialyl-lewisa oligosaccharides on human zonae pellucidae. These epitopes are potential ligands of cell adhesion molecules named selectins which are known to play a role in endothelium-leukocyte interactions. By immunofluorescence, we find the leukocyte selectin (L-selectin) on the spermatozoa head. Preincubation of spermatozoa with an anti-L-selectin monoclonal antibody produces a significant inhibition of zona pellucida tight binding, under hemizona assay conditions. In contrast, preincubation of the zonae pellucidae with anti-sialyl-lewisx or anti-sialyl-lewisa antibodies does not produce a significant inhibition of spermatozoa binding. Western blot analysis of spermatozoa-detergent extracts revealed a band at approximatively 90 kDa with the anti-L-selectin monoclonal antibody. This spermatozoa selectin could play a role in human spermatozoa-zona pellucida binding. Zona-ligands have yet to be precisely defined.

Blotting, Western↗

[Hypercalcemia in cancer patients. Who, when and how to treat?].

The most frequent, potentially fatal, metabolic complication in cancer patients is hypercalcemia. After a discussion of cancer-associated hypercalcemia, we propose an individualized intervention model based on an analysis of the clinical situation, the prognosis, and available treatment options.

Humans↗

[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↗

[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↗

Identification of two acidic residues involved in the catalysis of xylanase A from Streptomyces lividans.

On the basis of similarities between known xylanase sequences of the F family, three invariant acidic residues of xylanase A from Streptomyces lividans were investigated. Site-directed-mutagenesis experiments were carried out in Escherichia coli after engineering the xylanase A gene to allow its expression. Replacement of Glu-128 or Glu-236 by their isosteric form (Gln) completely abolished enzyme activity with xylan and p-nitrophenyl beta-D-cellobioside, indicating that the two substrates are hydrolysed at the same site. These two amino acids probably represent the catalytic residues. Immunological studies, which showed that the two mutants retained the same epitopes, indicate that the lack of activity is the result of the mutation rather than misfolding of the protein. Mutation D124E did not affect the kinetic parameters with xylan as substrate, but D124N reduced the Km 16-fold and the Vmax. 14-fold when compared with the wild-type enzyme. The mutations had a more pronounced effect with p-nitrophenyl beta-D-cellobioside as the substrate. Mutation D124E increased the Km and decreased the Vmax. 5-fold each, while D124N reduced the Km 4.5-fold and the Vmax. 75-fold. The mutations had no effect on the cleavage mode of xylopentaose.

Base Sequence↗

Alteration of the cleavage mode and of the transglycosylation reactions of the xylanase A of Streptomyces lividans 1326 by site-directed mutagenesis of the Asn173 residue.

The amino acid replacement of Asn173 by Asp in the xylanase A (Xln A) of Streptomyces lividans significantly altered its enzymic properties. A time-course hydrolysis of xylan showed that the altered xylanase ([N173D] Xln A) initially produced larger amounts of xylose (X1), xylobiose (X2) and xylotriose (X3) than Xln A, but less xylotetraose (X4). The bond-cleavage frequencies were determined for both enzymes using xylopentaose (X5), xylotetraose (X4) and xylotriose (X3) labelled at the reducing end of the molecule. Xln A hydrolysed X5, yielding 56% X2 and 44% X3, while [N173D]Xln A liberated 90% X2 and only 10% X3. Both enzymes hydrolysed X4 into 100% X2 and X3 into 100% X1. Transglycosylation reactions were detected in HPLC hydrolysis patterns using high substrate concentrations, where larger products than the starting substrates were formed. Their subsequent degradation also affected the yield of hydrolysis products. Using X5 as substrate, products from xylohexaose (X6) up to xylooligosides larger than xylooctaose (X8) were synthesized by Xln A, while [N173D]Xln A produced only a small amount of xyloheptaose (X7) and X8. Xln A hydrolysed X5 into an equivalent amount of X4 and X2 and 1.5-fold more X3. However, [N173D]Xln A yielded the same amount of X3 and X2 but half as much X4. With X4 as substrate, Xln A synthesized twofold more X7 and X6 than [N173D]Xln A. Xln A liberated 1.4-fold more X3 than X2, while [N173D]Xln A yielded twofold more X2 than X3. Xln A liberated almost fourfold more X2 than X1 from X3, while [N173D]Xln A produced only twofold more X2 than X1. These results indicated that the negative charge introduced by the mutation greatly affected the transglycosylation reaction catalysed by this xylanase.

Amino Acid Sequence↗