Search

Active immunotherapy based on live attenuated bacterial vectors has matured in terms of industrial development and develops through a combination of three phenomena. First, active immunotherapy that stimulates an antigen-specific cytotoxic T-cell immune response has become a reality after several years of work. Second, there is still a need to identify vectors that can deliver antigens to the cytosol of antigen-presenting cells in vivo. Third, the recent progress in the understanding of bacterial lifestyle and in developing genetic engineering tools has enabled the design of bioengineered bugs that are capable of delivering antigens. Here, we review the mechanisms by which clinical bacterial vectors deliver antigens into the cytosol of antigen-presenting cells and summarize the development strategy of the three identified firms in this field.

Background/aims: The molecular mechanisms leading to Non-Alcoholic Steatohepatitis (NASH) are not fully understood. In mice, NASH can be inhibited by fenofibrate, a synthetic agonist for the nuclear receptor peroxisome proliferator activated receptor alpha, which regulates hepatic triglyceride metabolism. This study aimed to elucidate the relation between steatosis and inflammation in NASH in a human-like hyperlipidemic mouse model., Methods: Liver phenotype and gene expression were assessed in APOE2 knock-in mice that were fed a western-type high fat diet with or without co-administration of fenofibrate., Results: In response to a western diet, APOE2 knock-in mice developed NASH characterized by steatosis and inflammation. Strikingly, macrophage accumulation in the liver preceded the steatosis during progression of the disease. This phenotype was in line with gene expression patterns, which showed regulation of two major groups of genes, i.e. inflammatory and lipid genes. Fenofibrate treatment decreased hepatic macrophage accumulation and abolished steatosis. Moreover, a marked reduction in the expression of inflammatory genes occurred immediately after fenofibrate treatment., Conclusions: These data indicate that inflammation might play an instrumental role during the development of NASH in this mouse model. Inhibition of NASH by fenofibrate may be due, at least in part, to its inhibitory effect on pro-inflammatory genes.

To understand the cellular mechanisms of malignant transformation induced by constitutive activation of the ras oncogene (Ha-ras), we used a subtractive hybridization method (VGID) together with an integrative analytical procedure based upon literature databases in the form of extensive interaction graphs. We found 166 over- and under-expressed genes which, in the human MCF7-ras breast epithelial cell line, are involved in the different aspects of tumoral transformation such as defined signaling pathways, cellular growth, protection against apoptosis, extracellular matrix and cytoskeleton remodeling. Integrative analysis led to the construction of a physiological model defining cross-talk and signaling pathway alterations which explicitly suggested mechanisms directly involved in tumor progression. The model further suggested points and means of intervention which could induce cell death in Ha-ras-transformed cells specifically. These hypotheses were directly tested in vitro and found to be largely correct, hence indicating that these new analytical and technological approaches allow the discovery of pathology-associated cellular mechanisms and physiologically defined targets leading to phenotype-specific pharmacological interventions.

Purpose: To identify prognostic factors and treatment toxicity in a series of operable endometrial adenocarcinomas., Patients and Methods: Between November 1971 and October 1992, 437 patients (pts) with endometrial carcinoma, staged according to the 1988 FIGO staging system, underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy without (n = 140) or with (n = 297) pelvic lymph node dissection. The chronology of RT was not randomized and depended on the usual practices of the surgical teams. Group I: 79 pts received preoperative uterovaginal brachytherapy (mean total dose [MD]: 57 Gy). Group II: 358 pts received postoperative RT (196 pts received vaginal brachytherapy alone [MD: 50 Gy], 158 pts had external beam pelvis RT [EPRT] [MD: 46 Gy over 5 weeks] followed by vaginal brachytherapy [MD: 17 Gy], and 4 pts had EPRT alone [MD: 46 Gy over 5 weeks]). The mean follow-up was 128 months., Results: The 10-year disease-free survival rate was 86%. From 57 recurrences, 12 were isolated locoregionally. Multivariate analysis showed that independent factors decreasing the probability of disease-free survival were: histologic type (clear cell carcinoma, p = 0.038), largest histologic tumor diameter > 3 cm (p = 0.015), histologic grade (p = 0.008), myometrial invasion > 1/2 (p = 0.0055), and 1988 FIGO staging system (p = 9.10(-8)). In group II, the addition of EPRT did not seem to improve locoregional control. The postoperative complication rate was 7%. The independent factors increasing the risk of postoperative complications were FIGO stage (p = 0.02) and pelvic lymph node dissection (p = 0.011). The 10-year rate for grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 3.1%. EPRT independently increased the 10-year rate for grade 3 and 4 late radiation complications (R.R.: 5.6, p = 0.0096)., Conclusion: EPRT increases the risk of late radiation complications. After surgical and histopathologic staging with pelvic lymph node dissection, in a subgroup of intermediate risk patients (stage IA grade 3, IB-C and II), postoperative vaginal brachytherapy alone is probably sufficient to obtain a good therapeutic index. Results for patients with stage III tumor are not satisfactory.

Purpose: To identify prognostic factors and treatment toxicity in a series of operable endometrial adenocarcinomas., Methods and Materials: Between November 1971 and October 1992, 437 patients (pts) with endometrial carcinoma, staged according to the 1988 FIGO staging system (225 Stage IB, 107 Stage IC, 4 Stage IIA, 35 Stage IIB, 30 Stage IIIA, 6 Stage IIIB, and 30 Stage IIIC), underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy without (n = 140) or with (n = 297) pelvic lymph node dissection. The chronology of adjuvant RT was not randomized and depended on the usual practices of the surgical teams. Seventy-nine pts (Group I) received preoperative low-dose-rate uterovaginal brachytherapy (mean dose [MD]: 57 Gy). Three hundred fifty-eight pts (Group II) received postoperative RT. One hundred ninety-six pts received low-dose-rate vaginal brachytherapy alone (MD: 50 Gy). One hundred fifty-eight pts had external beam pelvic RT (MD: 46 Gy) followed by low-dose-rate vaginal brachytherapy (MD: 17 Gy). Four pts had external beam pelvic RT alone (MD: 47 Gy). The mean follow-up from the beginning of treatment was 128 months., Results: The 10-year disease-free survival rate was 86%. From 57 recurrences, only 12 were isolated locoregional recurrences. The independent factors decreasing the probability of disease-free survival were as follows: histologic type (clear-cell carcinoma, p = 0.038), largest histologic tumor diameter >3 cm (p = 0.015), histologic grade (p = 0.008), myometrial invasion > 1/2 (p = 0.005), and 1988 FIGO staging system (p = 9.10(-8)). In Group II, the addition of external beam pelvic RT did not seem to independently improve vaginal or pelvic control. The postoperative complication rate was 7%. The independent factors increasing the risk of postoperative complications were stage FIGO (p = 0.02) and pelvic lymph node dissection (p = 0.011). The 10-year rate for Grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 3.1%. External beam pelvic RT independently increased the rate for Grade 3 and 4 late complication (RR: 5.6, p = 0.0096)., Conclusion: Postoperative external beam pelvic RT increases the risk of late radiation complications. After surgical and histopathologic staging with pelvic lymph node dissection, in subgroup of "intermediate-risk" patients (Stage IA Grade 3, IB-C and II), postoperative vaginal brachytherapy alone is probably sufficient to obtain a good therapeutic index. Results for patients with Stage III tumor are not satisfactory.

A backcalculation approach allows a reconstruction of the history of hepatitis C virus (HCV) infection in France and predictions of mortality from hepatocellular carcinoma (HCC) related to the virus. The model uses information from the literature about the natural history of the disease, epidemiological data about infected subjects in three French cohorts, and mortality data from national statistics. It seeks to determine the annual transition probabilities from chronic hepatitis to cirrhosis and the HCV incidence per year in the past. These unknowns are found by fitting the observed deaths from HCC that are attributable to HCV. Optimal values for these unknowns then allow to project the number of HCC deaths attributable to HCV for each year through 2025 (for patients infected before 1996). The model traces the HCV epidemic in France back to around the 1940s. It predicts that HCC mortality related to HCV will continue to increase through 2020 in the absence of treatment, with a 150% increase in the yearly incidence among men and 200% among women. The model also confirms that progression to cirrhosis depends strongly on sex and age. At any age, the annual probability of progression is 10 times greater for men than for women. Moreover, for men aged between 61 and 70 years, this probability is 300 times greater than that for men aged between 21 and 40 years.

Purpose: Retrospective study to analyze the results of external beam radiation treatment with or without surgery for loco-regional recurrence of adenocarcinoma of the rectum following previous surgery without pre- or post-operative radiotherapy., Patients and Methods: Between March 1973 and November 1991, 211 patients with loco-regional recurrence of rectum cancer were treated with external beam radiation treatment. Radical surgery was the only initial treatment modality. Surgical resection of local recurrence was done in 36 patients and only 17 patients could undergo complete resection. Forty-seven patients underwent radiotherapy (RT) combined with surgery and 164 received external beam radiation treatment alone to a mean total dose of 46 Gy., Results: Among the 151 patients whose recurrence was revealed by pain, 64 (42%) were considered to have a complete symptomatic response after loco-regional treatment with radiosurgery or RT alone. The mean duration of response was 12 months. The 3-year overall survival rate was 16%. Five prognostic factors decreased the overall survival rate in multivariate analysis: high age, sex (male), concomitant distant metastasis, no tumor resection, and low total radiation dose with external beam radiation treatment alone. The 3-year overall survival rate for patients with completely resected recurrences was 39%., Conclusion: External beam RT treatment can only be considered a palliative symptomatic treatment. New techniques of early detection of local recurrence and new combined modalities approaches (radiation sensitizers or intra-operative radiotherapy) with surgical resection in some favorable cases should be studied.

Between December 1981 and December 1988, 329 consecutive patients with stage I and II breast cancers who underwent wide excision (n = 261) or quadrantectomy (n = 68) with (n = 303) or without (n = 26) axillary dissection were referred to radiotherapy. Final margins of resection were microscopically free from tumor involvement in all cases. Radiotherapy consisted in 40-45 Gy over 4-4.5 weeks to the breast, with (n = 168) or without (n = 161) regional nodal irradiation of 45-50 Gy over 4.5-5 weeks. A mean booster dose of 15 Gy was delivered to the primary site by iridium-192 implant in 169 patients (group 1) or by electrons in 160 patients (group 2). Twenty-seven percent (n = 88) of patients received tamoxifen for > or = 2 years. Adjuvant chemotherapy was administered in 22% (n = 71) of patients. Groups 1 and 2 were not strictly comparable. Group 1 patients were significantly younger, had smaller tumors, were treated with cobalt at 5 x 2 Gy per week and axillary dissection was more frequently performed. Group 2 patients were more frequently bifocal and more frequently treated by quadrantectomy and tamoxifen, and irradiation used accelerator photons at 4 x 2.50 Gy per week. No difference in terms of follow-up and survival rates was observed between the two groups. For all patients the 5- and 10-year local breast relapse rates were 6.7% and 11%, respectively. No difference was observed regarding local control either by the electron or the iridium-192 implant boosts. Axillary dissection and age had an impact on the breast cosmetic outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

The representation and display of protein surfaces are useful in many areas of molecular modeling, and surface shape study is particularly important in the analysis of protein-ligand interactions. We introduce here the notion of the molecular surface convex hull, allowing the depth of any molecular surface point to be defined. A two-dimensional (2D) map, the iso-depth contour map, and a three-dimensional (3D) representation, the iso-depth lines, allow the topography of a molecular surface to be displayed in terms of knobs (high depth) and holes (low depth).

The differentiation of T Lymphocytes within the thymus is an important biological phenomenon during which these cell acquire their functions to further control the immune system. Numerous experiments under various conditions have been devised to understand the different mechanisms involved in this complex process. Nevertheless, interpretation of these experiments lead to still contradictory debatable hypotheses. Modelisation of this process through classical simulation methods cannot be envisaged because they are not adapted to modifications of the model structure, which is the point of interest. For these reasons, we proposed a new approach of automatic search for model. The program consists of four independent connected modules: The generator produces model, based on the rationale of formal grammars. Protocol and experimental data are stored in a set of experiments. The simulator using a protocol and a model provides simulated results. Finally, the supervisor by comparing simulated results and experimental data, adapts the model parameters to increase their fit and either chooses a new experiment to explore, or modifies the model structure. Change of the model structure is performed among still unexplored models according to their "promise" level, which is iteratively evaluated relatively to previously explored models through a proposed model distance. The generator is written in Prolog and the other modules in C++. The architecture of the program allows us to modify or complete a module without changing anything in the other modules. As a consequence, the proposed modeling approach conceived to study T lymphocyte differentiation within the thymus remains independent of this biological phenomenon and can be applied to other biological problems.