Atypical citrate-fermenting Lactococcus lactis strains isolated from dromedary's milk.

AIM: The aim was to isolate and characterize Lactococcus strains with new properties compared to those of usual Lactococcus dairy starters derived from cow's milk. METHODS AND RESULTS: Algerian dromedary's milk was screened for proteolytic isolates able to grow rapidly on agar milk medium. PCR experiments revealed that 74 proteolytic isolates belonged to the genus Lactococcus and harboured the prtP gene encoding the lactococcal cell-surface proteinase. Among these, 85% were able to ferment citrate (Cit(+) phenotype) and were classified as Lactococcus lactis ssp. lactis biovar. diacetylactis. This classification was confirmed after sequencing of the 16S rDNA gene of five Cit(+) isolates. In contrast to dairy lactococci described in the literature, several Cit(+) isolates exhibited a tolerance to 50 degrees C (Ther(+)) and alkaline pH. Two genetic approaches allowed to show the presence of four independent plasmids (so-called pTher, pPrt, pLac, pCit) associated with the four respective phenotypes: Ther(+), cell-surface proteinase activity PrtP (PrtP(+)), lactose catabolism (Lac(+)) and citrate utilization (Cit(+)). Two types of pCit plasmid were amplified by inverse PCR: class 1 was characterized by a 9-kb plasmid harbouring the expected lactococcal citQRP operon and class 2 by a 23-kb plasmid harbouring the Leuconostoc cit cluster (citI-CitMCDEFGRP). CONCLUSIONS: This work enlarges knowledge of the biovariety diacetylactis by far mainly limited to the citrate-fermenting ability and suggests that the cit plasmid system of some lactococcal strains could have been acquired from another lactic acid bacteria (Leuconostoc spp.). SIGNIFICANCE AND IMPACT OF THE STUDY: This study reveals new potential dairy lactococci starters of the biovariety diacetylactis able to grow rapidly in milk at a higher temperature in addition to their casein, lactose and citrate-utilizing abilities.

Peptidases specific for proline-containing peptides and their unusual peptide-dependent regulation in Oenococcus oeni.

AIMS: Growth of the lactic acid bacterium (LAB) Oenococcus oeni, which is involved in malolactic fermentation during the winemaking process, is stimulated by peptides originating from yeast. In this study, we investigated the impact of peptides on O. oeni growth, peptidase activity and the expression of genes encoding the studied peptidases. METHODS AND RESULTS: Low levels of PepN activity and very high levels of PepI activity were observed in O. oeni, whereas levels of PepX activity were intermediate. The level of biosynthesis of these O. oeni peptidases was shown to depend on peptides present in the culture medium. These results were confirmed by transcriptional analyses of putative pep genes. The mechanism of repression by peptides did not involve a CodY-like regulator. CONCLUSIONS: Peptides from yeast decrease the levels of enzymatic activity and relative gene expression of O. oeni peptidases. Peptidases specific for proline-containing peptides are important for O. oeni nitrogen metabolism. SIGNIFICANCE AND IMPACT OF THE STUDY: We report here for the first time that the enzymes involved in the assimilation of proline-containing peptides by O. oeni differ from the well-described proteolytic system of milk LAB. This may reflect a specific adaptation to the wine environment.

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.

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.

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

Tamoxifen for the treatment of metastatic inflammatory breast carcinoma.

In this series, 65 patients with metastatic inflammatory breast carcinoma were treated with neoadjuvant chemotherapy followed by local regional treatment followed by adjuvant chemotherapy. All of these selected patients developed further metastatic disease and were treated at that time with tamoxifen alone. Measurements of hormone receptor levels were available for 46 patients. Four tumors were positive estrogen receptors and eight tumors were positive progesterone receptors. The objective response rate for tamoxifen therapy was 5% (3/65). No major side effects were observed. When the metastasis-free interval was over 19 months, the overall survival and after metastases survival rates were significantly increased. Our conclusion is that tamoxifen should not play any role in the palliative treatment of metastases in inflammatory breast carcinoma.

VP-16, cisplatin, doxorubicin, and bleomycin in metastatic Merkel cell carcinoma. Report of a case with long-term remission.

A complete response with combination chemotherapy was obtained in a patient with metastatic Merkel cell carcinoma. This complete response lasted 15 months. This case report demonstrates the chemosensitivity of this metastatic disease when treated with combination chemotherapy.

[Primary neuroendocrine cutaneous carcinoma or Merkel cell carcinoma. Review of the literature]. / Carcinomes neuroendocrines cutanés primitifs ou carcinomes à cellules de Merkel. Revue de la littérature.

The neuroendocrine carcinomas of the skin, also called Merkel cell carcinomas, are unusual malignancies mostly observed in the elderly. They are diagnosed by a pathologist: ultrastructural studies and immunohistochemistry support the diagnosis. The prognosis is poor. Lymph nodes and metastases quickly arise although sometimes, they are discovered immediately. A combination of surgery and radiotherapy is recommended. Metastases and unresectable tumors should be treated by chemotherapy.

[Carcinoma of the endometrium: review of the literature]. / Carcinome de léndomètre: revue de la littérature.

In endometrial adenocarcinoma, many risk factors have been demonstrated. Among them, tamoxifene is a factor of low risk. Any endometrial bleeding requires a gynecological exam in order to make an early diagnosis. The positive histologic diagnosis is more often after surgery which is necessary for histo-prognostic stage. Non conservative hysterectomy with pelvic lymphadenectomy (obturator chain) is recommended for the most frequent stages I and II. Radiation therapy alone is recommended for stage III. Palliative therapy (hormonotherapy or chemotherapy) could be proposed for the few stage IV.

[Radiotherapy of cancers of the pancreas and extrahepatic biliary tree. Gross tumor volume (GTV). Clinical target volume (CTV)]. / Radiothérapie des cancers du pancréas et des cancers des voies biliaires extra-hépatiques. Volume tumoral macroscopique (GTV). Volume-cible anatomoclinique (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.

[Volume-effect and radiotherapy [II]. Part II: volume-effect and normal tissue]. / Effet volume en radiothérapie [II]. Deuxième partie : volume et tolérance des tissus sains.

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.

[Operable stage IB and II cancer of the uterine neck: retrospective comparison between preoperative utero-vaginal curietherapy and initial surgery followed by radiotherapy]. / Cancer du col utérin stades IB et II opérable: comparaison rétrospective entre curiethérapie utérovaginale préopératoire et chirurgie première suivies d'une radiothérapie.

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.

[Long term results of exclusive chemotherapy for glottic squamous cell carcinoma complete clinical responders after induction chemotherapy]. / Résultats à long-terme de la chimiothérapie exclusive des cancers épidermoïdes glottiques.

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.

Bactericidal efficiency and mode of action: a comparative study of photochemistry and photocatalysis.

In order to compare the disinfection potential of photocatalysis and photochemistry, the effects of these two processes on bacteria in water were investigated under exposure to UV-A and UV-C. The well-known bacterial model Escherichia coli (E. coli) was used as the experimental organism. Radiation exposure was produced with an HPK 125 W lamp and the standard TiO(2) Degussa P-25 was used as the photocatalyst. Firstly, the impact of photocatalysis and photochemistry on the cultivability of bacterial cells was investigated. UV-A radiation resulted in low deleterious effects on bacterial cultivability but generated colonies of size smaller than average. UV-C photocatalysis demonstrated a greater efficiency than UV-A photocatalysis in altering bacterial cultivability. From a cultivability point of view only, UV-C radiation appeared to be the most deleterious treatment. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit was then used to assess the modifications in bacterial membrane permeability. UV-A radiation did not induce any alterations in bacterial permeability for 420 min of exposure whereas only a few minutes of exposure to UV-C radiation, with the same total radiance intensity, induced total loss of permeability. Moreover, after 20 and 60 min of exposure to UV-C and UV-A photocatalysis respectively, all bacteria lost their membrane integrity, suggesting that the bacterial envelope is the primary target of reactive oxygen species (ROS) generated at the surface of TiO(2) photocatalyst. These results were further confirmed by the formation of malondialdehyde (MDA) during the photocatalytic inactivation of bacterial cells and suggest that destruction of the cell envelope is a key step in the bactericidal action of photocatalysis. The oxidation of bacterial membrane lipids was also correlated with the monitoring of carboxylic acids, which can be considered as representatives of lipid peroxidation by-products. Finally, damages to bacterial morphology induced by UV-C photocatalysis and photochemistry were investigated through Scanning electron microscopy (SEM). Bacterial cells were observed on microscopy pictures at exposure durations corresponding to a loss of cultivability. After 90 min of exposure to UV-C radiation, bacterial cells showed little alteration of their outer membrane whereas they suffered deep deleterious damages under UV-C photocatalysis exposure.