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D Atlan

Publications and source records attributed to D Atlan.

At least 19 recordsLinked to original sources
PubMed2005

Impact of EGFR expression on colorectal cancer patient prognosis and survival.

BACKGROUND: Epidermal growth factor receptor (EGFR) is overexpressed in many types of cancers, especially colorectal cancer (CRC), and seems to reflect more aggressive histological and clinical behaviors. The aim of this study was to evaluate EGFR immunohistochemical reactivity in CRC biopsies, and to analyze its relationship with various histological and clinical characteristics and survival. PATIENTS AND METHODS: A composite EGFR score, obtained by multiplying the grade (% positive cells) by the intensity of labeling (0-9) was used to define patients with low or high EGFR expression whose clinicopathological features were then compared. Univariate tests and multivariate Cox proportional hazards model were applied for data analysis. RESULTS: Tissue sections from 150 CRC patients with a median follow-up of 40 months were examined. Median patient age at diagnosis was 70 years (range 38-89 years). EGFR reactivity was positive for 143 patients (97%) and high for 118 (80%). According to multivariate analysis, EGFR overexpression was significantly associated with tumor stage, with a higher percentage of EGFR overexpression in T3 than T4 (P=0.003) and not with overall survival. CONCLUSIONS: EGFR was overexpressed in this CRC patient population and was significantly associated with TNM (tumor-node-metastasis) stage T3. In the context of a new therapeutic strategy using EGFR-targeted therapies, although EGFR remains a controversial prognostic factor, this expression-stage association may play a crucial role in a decision to initiate an adjuvant treatment.

Adult↗
PubMed2005

Comparative analysis of the exopolysaccharide biosynthesis gene clusters from four strains of Lactobacillus rhamnosus.

The exopolysaccharide (EPS) biosynthesis gene clusters of four Lactobacillus rhamnosus strains consist of chromosomal DNA regions of 18.5 kb encoding 17 ORFs that are highly similar among the strains. However, under identical conditions, EPS production varies considerably among these strains, from 61 to 1611 mg l(-1). Fifteen genes are co-transcribed starting from the first promoter upstream of wzd. Nevertheless, five transcription start sites were identified by 5'-RACE PCR analysis, and these were associated with promoter sequences upstream of wzd, rmlA, welE, wzr and wzb. Six potential glycosyltransferase genes were identified that account for the assembly of the heptasaccharide repeat unit containing an unusually high proportion of rhamnose. Four genes involved in the biosynthesis of the sugar nucleotide precursor dTDP-L-rhamnose were identified in the EPS biosynthesis locus, which is unusual for lactic acid bacteria. These four genes are expressed from their own promoter (P2), as well as co-transcribed with the upstream EPS genes, resulting in coordinated production of the rhamnose precursor with the enzymes involved in EPS biosynthesis. This is believed to be the first report demonstrating that the sequence, original organization and transcription of genes encoding EPS production are highly similar among four strains of Lb. rhamnosus, and do not vary with the amount of EPS produced.

Base Sequence↗
PubMed2004

[Long term results of exclusive chemotherapy for glottic squamous cell carcinoma complete clinical responders after induction chemotherapy].

OBJECTIVES: To evaluate the long-term results of exclusive chemotherapy for T1-T3N0M0 glottic squamous cell carcinoma complete clinical responders after induction chemotherapy. MATERIAL AND METHODS: Between 1985 and 2000, 69 patients with glottic squamous cell carcinoma complete clinical responders after induction chemotherapy were managed with exclusive chemotherapy at our department. Chemotherapy associated platinum and fluorouracil. This retrospective analysis evaluated actuarial survival, treatment morbidity, oncologic events and laryngeal preservation. Various independent factors were tested for potential correlation with survival and local recurrence. RESULTS: The 5-year Kaplan-Meier actuarial survival, local control, lymph node control estimate were 83,6%, 64,8%, 98,6% respectively. Chemotherapy never resulted in death. The 10-year actuarial metachronous second primary tumors estimate was 32%. The overall laryngeal preservation rate was 98,6%. CONCLUSION: Altogether our data and the review of the literature suggest that in patients achieving a complete clinical response after and induction based chemotherapy regimen, the completion of an exclusive chemotherapy regimen appears to be a valid alternative to the conventional use of radiotherapy or chemo-radiation protocols.

Adult↗
PubMed2003

Nasopharyngeal carcinomas: an update.

Among the group of head and neck cancers, nasopharyngeal carcinomas (NPC) represent a distinct entity in terms of their epidemiology, clinical presentation, biological markers, carcinogenic risk factors, prognostic factors, treatment and outcome. Undifferentiated NPC (UCNT), the most frequent histological type, is endemic in certain regions, especially in South East Asia. The disease has also been associated with the presence of the Epstein-Barr Virus (EBV). Although NPC is a radiosensitive and chemosensitive tumour, a substantial number of patients develop local recurrence or distant metastases. For patients with locoregional advanced disease, it is well known that conventional radiotherapy is insufficient in terms of both the local control rates and distant metastases. New techniques of radiation and new combined radiotherapy and chemotherapy modalities have been evaluated in numerous clinical trials in recent years. The purpose of this article is to review the current knowledge in terms of the epidemiology, biology, prognosis, management and outcome of patients with NPC.

Antineoplastic Agents↗
PubMed2003

[Volume-effect and radiotherapy [II]. Part II: volume-effect and normal tissue].

The first part of our work has focused on the relationship between tumor volume and tumor control. Indeed, it is well known that the importance of irradiated volume could be a main parameter of radiation-induced complications. Numerous mathematical models have described the correlation between the irradiated volume and the risk of adverse effects. These models should predict the complication rate of each treatment planning. At the present time late effects have been the most studied. In this report we firstly propose a review of different mathematical models described for volume effect. Secondly, we will discuss whether these theoretical considerations can influence our view of radiation treatment planning optimization.

Humans↗
PubMed2002

[Operable stage IB and II cancer of the uterine neck: retrospective comparison between preoperative utero-vaginal curietherapy and initial surgery followed by radiotherapy].

PURPOSE: To identify prognostic factors and treatment toxicity in a series of operable stages IB and II cervical carcinomas. PATIENTS AND METHODS: Between May 1972 and January 1994, 414 patients (pts) with cervical carcinoma staged according to the 1995 FIGO staging system underwent radical hysterectomy with (n = 380) or without (n = 34) bilateral pelvic lymph node dissection. Lateral ovarian transposition to preserve ovarian function was performed on 12 pts. The methods of radiation therapy (RT) were not randomised and depended on the usual practices of the surgical teams. Group I: 168 pts received postoperative RT (64 pts received vaginal brachytherapy alone [mean total dose (MD): 50 Gy], 93 pts had external beam pelvis RT (EBPRT) [MD: 45 Gy over 5 weeks] followed by vaginal brachytherapy [MD: 20 Gy], and 11 pts had EBPRT alone [MD: 50 Gy over 6 weeks]. Group II: 246 pts received preoperative utero-vaginal brachytherapy [MD: 65 Gy], and 32 of theses 246 pts also received postoperative EBPRT [MD: 45 Gy over 5 weeks] delivered to the parametric and the pelvic lymph nodes with a midline pelvic shield. The mean follow-up was 106 months. RESULTS: The 10-year disease-free survival (DFS) rate was 80%. From 75 recurrences, 35 were isolated locoregional. Multivariate analysis showed that independent factors decreasing the probability of DFS were: both exo and endocervical tumour site (p = 0.047), lymph-vascular space invasion (p = 0.041), age < or = 51 yr (p = 0.013), 1995 FIGO staging system (stage IB1 vs stage IIA, p = 0.004, stage IB1 vs stage IB2, p = 0.0009, and stage IB1 vs stage IIB with 1/3 proximal parametrical infiltration, p = 0.00002), and histological pelvic involved lymph nodes (p = 0.00009). Methods of adjuvant RT did not influence the probability of DFS (group I vs group II, p = 0.10). The postoperative complication rate was 10.2% in group I and 8.9% in group II (p = 0.7) but the postoperative urethral complication rate necessitating surgical intervention with reimplantation was lower in group I than in group II (0.6% vs 2.3%, respectively, p = 0.03). The 10-year rate for grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 10.4%. EPRT significantly increased the 10-year rate for grade 3 and 4 late radiation complications (yes vs no: 22% vs 7%, respectively, p = 0.0002). CONCLUSION: In our series, the methods of adjuvant RT (primary surgery vs preoperative uterovaginal brachytherapy) do not seem to influence the prognosis of the stage IB, IIA, and IIB (with 1/3 proximal parametrical involvement only) cervical carcinomas. The postoperative EPRT applied according to histopathological risk factors after surgical treatment increases the risk of late radiation complications.

Adult↗
PubMed2001

[Radiotherapy of cancers of the pancreas and extrahepatic biliary tree. Gross tumor volume (GTV). Clinical target volume (CTV)].

Anatomical data of pancreas, biliary tree, regional lymph nodes is required to define GTV and CTV. In case of postoperative irradiation, CTV is designed in collaboration with radiation oncologist and surgeon oncologist. For exclusive radiotherapy, endodigestive ultrasonography, CT scan and MRI could help radiation oncologist defining GTV. Although, accuracy of all the imaging techniques in past years remains poor. Currently, no available literature is published regarding security margins for the definition of CTV. Therefore, recommendations according to clinical experience are proposed.

Biliary Tract Neoplasms↗
PubMed2001

Autoregulation of the biosynthesis of the CcpA-like protein, PepR1, in Lactobacillus delbrueckii subsp bulgaricus.

PepR1 from Lactobacillus delbrueckii subsp bulgaricus (Lb. bulgaricus) is involved in biosynthesis regulation of the prolidase PepQ. In this paper, we demonstrated that Lb. bulgaricus PepR1 biosynthesis is not constitutive like those of several bacteria but is auto-regulated and depends on the glucose concentration of the culture medium. We propose a model for PepQ regulation by PepR1.

Bacterial Proteins↗
PubMed2000

Linac radiosurgery for cerebral arteriovenous malformations: results in 169 patients.

PURPOSE: To present the SALT group results using Linac radiosurgery (RS) for AVM in 169 evaluable patients treated from January 1990 thru December 1993. METHODS AND MATERIALS: Median age was 33 years (range 6-68 years). Irradiation was the only treatment in 55% patients. Other treatment modalities had been used prior to RS in 45%: one or more embolizations in 36%, surgery in 6%, and embolization and surgery in 3% patients. Nidus were supratentorial in 94% patients, infratentorial in 6% patients. Circular 15 MV x-ray minibeams (6-20 mm) were delivered in coronal arcs by a GE-CGR Saturne 43 Linac. Patient set-up included a Betti arm-chair, a Talairach frame. Prescribed peripheral dose was 25 Gy on the 60%-70% isodose (max dose 100%). Arteriographic results were reassessed in December 1997 at 48 to 96 months follow-up. RESULTS: The overall obliteration rate (OR) was 64% (108/169). AVM volumes ranged from 280 to 19,920 mm(3), median 2460 mm(3). OR was 70% for AVM </= 4200 mm(3) 4200 mm(3) (p 25 mm (p = 0.04). OR was 71%, in the absence of embolization, vs. 54% for previously embolized nidus (p = 0.03). OR was 71% for monocentric RS vs. 54% for multi-isocenters (p 28 Gy vs. 55% for values </= 28 Gy (p 79% vs. 57% for lower values (p 17 Gy, vs. 59% for mLd </= 16 Gy (p 40%, vs. 54% for mLi </= 40% (p 85% vs. 60% for CR </= 84% (NS). For patients treated according to our protocol, i.e., 24-26 Gy on the 60%-70% isodoses, OR was higher (68%) than for other patients (47%) (p = 0.02). After multivariate analysis, absence of previous embolization and mono isocentric-irradiation were independent factors predicting obliteration. Complications were: recurrent hemorrhage, 4 patients (1 patient died); brain necrosis on MRI, 2 patients; subsequent epilepsy, 4 patients; other subsequent neurologic deficits, 3 patients. CONCLUSION: Overall OR was 64% (48-96 months follow-up). After monovariate analysis higher ORs were associated with smaller volumes </= 4200 mm(3), smaller nidus size </= 25 mm, absence of prior embolization, monoisocentric RS, higher values for mean and minimum lesion doses and compliance to our protocol. Higher values for the peripheral dose and isodose tended to give better results. Multivariate analysis showed that the absence of prior embolization and monoisocentric irradiation were independent factors predicting successful irradiation.

Adolescent↗
PubMed2000

Hydrolysis of sequenced beta-casein peptides provides new insight into peptidase activity from thermophilic lactic acid bacteria and highlights intrinsic resistance of phosphopeptides.

The peptidases of thermophilic lactic acid bacteria have a key role in the proteolysis of Swiss cheeses during warm room ripening. To compare their peptidase activities toward a dairy substrate, a tryptic/chymotryptic hydrolysate of purified beta-casein was used. Thirty-four peptides from 3 to 35 amino acids, including three phosphorylated peptides, constitute the beta-casein hydrolysate, as shown by tandem mass spectrometry. Cell extracts prepared from Lactobacillus helveticus ITG LH1, ITG LH77, and CNRZ 32, Lactobacillus delbrueckii subsp. lactis ITG LL14 and ITG LL51, L. delbrueckii subsp. bulgaricus CNRZ 397 and NCDO 1489, and Streptococcus thermophilus CNRZ 385, CIP 102303, and TA 060 were standardized in protein. The peptidase activities were assessed with the beta-casein hydrolysate as the substrate at pH 5.5 and 24 degrees C (conditions of warm room ripening) by (i) free amino acid release, (ii) reverse-phase chromatography, and (iii) identification of undigested peptides by mass spectrometry. Regardless of strain, L. helveticus was the most efficient in hydrolyzing beta-casein peptides. Interestingly, cell extracts of S. thermophilus were not able to release a significant level of free proline from the beta-casein hydrolysate, which was consistent with the identification of numerous dipeptides containing proline. With the three lactic acid bacteria tested, the phosphorylated peptides remained undigested or weakly hydrolyzed indicating their high intrinsic resistance to peptidase activities. Finally, several sets of peptides differing by a single amino acid in a C-terminal position revealed the presence of at least one carboxypeptidase in the cell extracts of these species.

Amino Acid Sequence↗
PubMed1999

The prolyl aminopeptidase from Lactobacillus delbrueckii subsp. bulgaricus belongs to the alpha/beta hydrolase fold family.

Prolyl aminopeptidase (PepIP) of Lactobacillus delbrueckii subsp. bulgaricus displays the Gly-x-Ser-x-Gly-Gly consensus motif surrounding the catalytic serine of the prolyl oligopeptidases family. Sequence comparison revealed that this motif and two other domains appear well conserved among bacterial PepIPs and members of the alpha/beta hydrolase fold family. Secondary structural predictions of PepIP were performed from amino acid sequence and corroborated by circular dichroism analysis. These predictions well matched the core structure of alpha/beta hydrolases organised in eight beta-sheets connected by alpha-helices. We obtained 26 mutants of PepIP by chemical or site-directed mutagenesis. Most substitutions associated with stable and inactive mutant proteins were mainly located in the three conserved boxes (including the catalytic serine motif). Taken together, our results strongly suggest that PepIP belongs to the alpha/beta hydrolase fold family and that Ser107, Asp246 and His273 constitute the catalytic triad of the enzyme.

Amino Acid Sequence↗