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L Ayadi

Publications and source records attributed to L Ayadi.

15 recordsLinked to original sources
PubMed2006

[Gingival metastasis in breast phyllodes tumor].

BACKGROUND: The metastasis of oral cavity is rare. We report a gingival metastasis in the course of low grade phyllode sarcoma of the breast which is usually little metastatic. CASE-REPORT: A 44 year old woman was operated two years ago for a phyllod sarcoma of the breast histologically confirmed. She presented for a mandibular exophytic tumour associated with haemorrhagic, necrotic, ulcerated and bulking gingivitis surrounding at the level of the maxillary and mandibular gingiva. The examination revealed multiple nodular lesions of the trunk and the scalp. The histological examination confirmed the diagnosis of cutaneous and gingival metastasis of the phyllod sarcoma of the breast. The evolution was rapidly fatal. DISCUSSION: The gingival metastasis are rare tumours with a bad prognostic. Their diagnosis is based on clinical and histological arguments and must be made different from chronic gingivitis which can be associated.

Adult↗
PubMed2006

[Granulosa-cell tumor of the ovary: report of 16 cases].

OBJECTIVE: The aim of this work was to describe the epidemiological, pathological and clinical features of granulosa cell tumors and to study the different prognostic factors in order to determine an appropriate therapeutic attitude. PATIENTS AND METHODS: We proceeded with a retrospective study of 16 cases of granulosa cell tumors of the ovary diagnosed over a period of 10 years (1994-2003). These cases included one case of juvenile type and 15 adult types. RESULTS: Mean patient age was 46 years for the adult type (range 20-70 years) and 35 years for the juvenile type; 19% of the patients were nulliparous, 31% were menopausals. The predominant symptom was abdomino-pelvic pain with frequent hormonal manifestations. Mean tumor size was 10.5 cm with a solido-cystic aspect in 50% of cases. The treatment was surgical in all cases. Among the 16 patients, 14 (87.5%) were diagnosed at stage I and one (6.2%) at stage II. The juvenile tumor was at stage IV at time of diagnosis and only adjuvant chemotherapy was given. No relapse nor recurrence were noted for the adult type after a mean follow up of 2 years 2 months. For the juvenile form, locoregional recurrence with liver metastasis developed after 9 months. CONCLUSION: Granulosa cell tumor of the ovary is an uncommon neoplasm. The adult form progresses slowly and often is diagnosed in an early stage of disease. Surgery is indicated. The juvenile forms are more exceptional and more aggressive. A prolonged post therapeutic follow-up is necessary because of the risk of recurrences, late and exceptional for the adult form but frequent and early for the juvenile form.

Adult↗
PubMed2005

[Malignant struma ovarii: a case report].

Malignant transformation of struma ovarii is exceptional (less than 1%). The histolological diagnosis of malignancy is difficult especially in the well differentiated forms. Immunohistochemistry is highly contributive in the anaplastic forms. The prognosis is relatively favorable except for the metastatic and undifferentiated forms. We report a case of malignant struma ovarii with metastasis observed in a 65-year-old woman who died rapidly from her disease. In light of this observation, we discuss the diagnositic, management and outcome features of these particular tumors.

Aged↗
PubMed2004

[Palpebral seborrheic keratosis: a case study].

INTRODUCTION: Seborrheic keratosis is the most frequent palpebral tumor, observed for the most part in the second half of life. It may be confused clinically with a basal cell carcinoma or a melanoma. The histopathological study confirms the diagnosis. OBSERVATION: A 69-year-old man presented with a giant superior palpebral tumor leading to ptosis of the eyelid, which had evolved over 5 years. Examination found a pigmented cerebriform multilobed granulated mass, with a smooth surface and a more or less seborrheic aspect, pedicled in places, covering the entire eyelid but sparing the internal angle. This aspect suggested melanoma, basal cell carcinoma or seborrheic keratosis. Histological biopsy revealed basal cell carcinoma. Excision with palpebral reconstitution using palpebral flaps was performed. The histopathological analysis of the tumor concluded in seborrheic keratosis. DISCUSSION: Seborrheic keratosis is a frequent tumor of the face and eyelids. Its highly pigmented clinical aspect can be confounded with a nevus or a melanoma, whereas the histological aspect can suggest basal cell carcinoma or squamous cell carcinoma, but the basal membrane is always intact. Several treatments have been proposed, including electrocoagulation, cryotherapy, dermabrasion, as well as CO2 laser treatment. However, when there is doubt with regard to the histological nature, surgery is preferred. CONCLUSION: This was a case of seborrheic keratosis, atypical in that it covered the entire upper eyelid and produced a highly disfiguring aspect and functional problems, requiring surgical treatment with eyelid reconstruction.

Aged↗
PubMed2003

[Cellular hemangioma of the parotid gland associated with an infection by cytomegalovirus].

We report a case in a two and a half month old boy presenting a mass in the right parotid gland. Sonography showed a vascular tumor. Magnetic resonance imaging showed an expansive process of the parotid gland measuring 61 x 39 mm taking the contrast with hypo signal in T1 and hyper signal in T2-weighted images. The parotid was extirpated with preservation of the facial nerve. Microscopically the diagnosis of cellular hemangioma associated with CMV infection was made. Hemangiomas of the parotid gland is frequent; the most common tumor in children; the association of juvenile hemangioma of the parotid gland and cytomegalovirus (CMV) is extremely rare: a single case was reported in the literature. The pathologic significance of this association is still discussed, although several experimental studies suggested a relationship between the infection by the cytomegalovirus and this tumor. Our objective is to describe the anatomo-clinical aspects of this lesion and to elucidate the pathologic significance of this association.

Cytomegalovirus Infections↗
PubMed2002

[Colonic granulocytic sarcoma: a case report].

Granulocytic sarcoma is a rare tumor composed of immature cells of the granulocytic series which usually occurs as a secondary manifestation of acute leukaemia. We report the case of a 60 years old woman without particular previous pathologies who was hospitalised for chronic diarrhea developed in a context of health impairment state. The blood cell count revealed severe leucopenia and thrombopenia; an emergency right colectomy was accomplished. The histologic examination showed granulocytic sarcoma of the ascending colon. The death occurred rapidly as a consequence of a toxic shock. This observation seems to be the sixth case report of the granulocytic large bowel sarcoma in the literature which likely complicated a pre-existant and unknown myeloid leukaemia.

Biopsy↗
PubMed2000

The impact of abasic sites on DNA flexibility.

We use internal coordinate molecular mechanics calculations to study the impact of abasic sites on the conformation and the mechanics of the DNA double helix. Abasic sites, which are common mutagenic lesions, are shown to locally modify both the groove geometry and the curvature of DNA in a sequence dependent manner. By controlled twisting and bending, it is also shown that these lesions modify the deformability of the duplex, generally increasing its flexibility, but again to an extent which depends on the nature of the abasic site and on the surrounding base sequence. Both the conformational and mechanical influence of this type of DNA damage may be significant for recognition and repair mechanisms.

Computer Simulation↗
PubMed1999

Abasic sites in duplex DNA: molecular modeling of sequence-dependent effects on conformation.

Molecular modeling calculations using JUnction Minimization of Nucleic Acids (JUMNA) have been used to study sequence effects on the conformation of abasic sites within duplex DNA. We have considered lesions leading to all possible unpaired bases (X), adenine, guanine, cytosine, or thymine contained within two distinct sequence contexts, CXC and GXG. Calculations were carried out on DNA 11-mers using extensive conformational search techniques to locate the most stable abasic conformations and using Poisson-Boltzmann corrected electrostatics to account for solvation effects. The results, which are in very good agreement with available experimental data, point to strong sequence effects on both the position of the unpaired base (intra or extrahelical) and on the overall curvature induced by the abasic lesion. For CXC, unpaired purines are found to lie within the helix, while unpaired pyrimidines are either extrahelical or in equilibrium between the intra and extrahelical forms. For GXG, all unpaired bases lead to intrahelical forms, but with marked, sequence-dependent differences in induced curvature.

Base Pairing↗
PubMed1999

Experimental and theoretical studies of the conformational perturbations induced by an abasic site.

The three-dimensional structure of the natural undecamer duplex d(CGCACACACGC). d(GCGTGTGTGCG) has been determined by the combined use of NMR spectroscopy and restrained molecular dynamics (rMD) and also by molecular mechanics calculations using the JUMNA program without experimental distance constraints. Both procedures have also been used to model the abasic structure d(CGCACOCACGC).d(GCGTGTGTGCG), where 'O' indicates a modified abasic site: 3-hydroxy-2-(hydroxymethyl) tetrahydrofuran. For the natural duplex, 134 interproton distances have been obtained by complete relaxation matrix analysis of the NOESY cross-peaks intensities, using MARDIGRAS software. These distances along with 100 torsion angles for sugar ring and additional data derived from canonical A and B-DNA, have been used for structures refinement by restrained molecular dynamics. Comparison of the natural oligomer with the abasic structure obtained earlier by NMR/rMD (Y. Coppel, N. Berthet, C. Coulombeau, Ce. Coulombeau, J. Garcia and J. Lhomme, Biochemistry 36, 4817-4830, 1997) confirms that the creation of an abasic site, in this sequence context, leads to marked helix kinking. It is also shown that the JUMNA procedure is capable of reproducing the overall structural features of the natural and damaged DNA conformations without the use of experimental constraints.

Base Sequence↗
PubMed1998

Functional and structural characterization of the prp3 binding domain of the yeast prp4 splicing factor.

Nuclear pre-mRNA splicing occurs in a large RNA-protein complex containing four small nuclear ribonucleoprotein particles (snRNPs) and additional protein factors. The yeast Prp4 (yPrp4) protein is a specific component of the U4/U6 and U4/U6-U5 snRNPs, which associates transiently with the spliceosome before the first step of splicing. In this work, we used the in vivo yeast two-hybrid system and in vitro immunoprecipitation assays to show that yPrp4 interacts with yPrp3, another U4/U6 snRNP protein. To investigate the domain of yPrp4 that directly contacts yPrp3, we introduced deletions in the N-terminal half of yPrp4 and point mutations in the C-terminal half of the molecule, and we tested the resulting prp4 mutants for cell viability and for their ability to interact with yPrp3. We could not define any particular sequence in the first 161 amino acid residues that are specifically required for protein-protein interactions. However, deletion of a small basic-rich region of 30 amino acid residues is lethal to the cells. Analysis of the C terminus prp4 mutants obtained clearly shows that this region of yPrp4 represents the primary domain of interaction with yPrp3. Interestingly, yPrp4 shows significant similarity in its C-terminal half to the beta-subunits of G proteins. We have generated a three-dimensional computer model of this domain, consisting of a seven-bladed beta-propeller based on the crystalline structure of beta-transducin. Several lines of evidence suggested that yPrp4 is contacting yPrp3 through a large flat surface formed by the long variable loops linking the beta-strands of the propeller. This surface could be used as a scaffold for generating an RNA-protein complex.

Amino Acid Sequence↗
PubMed1997

Mutations within the yeast U4/U6 snRNP protein Prp4 affect a late stage of spliceosome assembly.

We showed previously that the yeast Prp4 protein is a spliceosomal factor that is tightly associated with the U4, U5, and U6 small nuclear RNAs. Moreover, Prp4 appears to associate very transiently with the spliceosome before the U4 snRNA dissociates from the spliceosome. Prp4 belongs to the Gbeta-like protein family, which suggests that the Prp4 Gbeta motifs could mediate interactions with other components of the spliceosome. To investigate the function of the Gbeta motifs, we introduced mutations within the second WD-repeat of Prp4. Among the 35 new alleles found, 24 were pseudo wild-type mutants, 8 failed to grow at any temperature, and 3 were conditional sensitive mutants. The biochemical defects of the three thermosensitive prp4 mutants have been examined by immunoprecipitation, native gel electrophoresis, and glycerol gradient centrifugation. First, we show that snRNP formation is not impaired in these mutants and that Prp4 is present in the U4/U6 and U4/U6-U5 snRNP particles. We also demonstrate that spliceosome assembly is largely unaffected despite the fact that the first step of splicing does not occur. However, both Prp4 and U4 snRNA remain tightly associated with the spliceosome and this blocks the transition toward an active form of the spliceosome. Our results suggest a possible role of Prp4 in mediating important conformational rearrangements of proteins within the spliceosome that involve the region containing the Gbeta-repeats.

Amino Acid Sequence↗
PubMedDate not supplied

[Giant sebaceous gland hyperplasia of the vulva].

BACKGROUND: Sebaceous gland hyperplasia is an epithelial tumour with sebaceous differentiation. Genital involvement is rare. In this paper, we report a new case of sebaceous gland hyperplasia of the vulva. CASE REPORT: A 27 year-old woman presented multiple polypoid lesions of the lower third of left labium majus. The lesions were soft to the touch, measured 5 cm in length and were painless. The cutaneous biopsy confirmed the diagnosis of sebaceous gland hyperplasia of the vulva. Surgical excision was performed in two separate procedures and was successful. DISCUSSION: This case was unusual in terms of the site, the clinical appearance and the weeping seen due to the high concentration of hyperplasic sebaceous glands.

Adult↗