Cutaneous leishmaniasis: progress towards a vaccine

Leishmaniases are vector-borne diseases due to the protozoan parasite Leishmania . Since no prevention method is available and as current therapy is costly, often poorly tolerated and not always efficacious, the development of alternative therapies, including vaccines, constitutes the priority in the fight of Leishmania infection. This review focuses on recent advances in the development of vaccines against leishmaniasis, with emphasis on the cutaneous form. Indeed, the fact that recovery from leishmaniasis is associated with immunity against new infection provides a rational basis for the development of vaccination strategy against infection with Leishmania . Evidence from animal studies demonstrate that protection can be achieved following infection with live-attenuated Leishmania as well as through immunization with purified proteins or DNA vaccines. In addition, recent results have shown that immunization against the saliva of the insect vector could have synergistic effects with conventional vaccination. Finally, vaccination using dendritic cells was recently demonstrated as a possible tool for Leishmania vaccination.     

Contribution of microdissection for the detection of microsatellite instability in colorectal cancer

The determination ofmicrosatellite instability (MSI) is an important step in the identification of familial colorectal cancer such as hereditary nonpolyposis colon cancer. It could also be of interest in the therapeutic management of sporadic cancer. International criteria for the determination of MSI have been published, recommending the use of microdissection. The aim of this work was to evaluate the impact of contaminant normal DNA in tumor samples for MSI assessment in colorectal cancer using a microdissection technique. We performed a comparative analysis of the microsatellite status between total DNA (DNA extracted from whole tumor samples) and microdissected DNA in 3 different regions from 23 cases of colorectal cancer. Six microsatellites were amplified using fluorescent polymerase chain reaction. We analyzed 9 cases with MSI and 14 cases without instability, with similar results between total DNA and microdissected DNA. Moreover, within a same tumor, the MSI phenotype was observed regardless of the region analyzed. Thus, this work shows the reproducibility of the MSI phenotype throughout a tumor. However, we observed a regional heterogeneity of the MSI profile, consisting of variations in the number and the size of unstable alleles within different regions. This result reflects the genetic heterogeneity of colorectal cancer with MSI. In the 14 cases without instability, we observed an increase of more than 60% in the loss of heterozygosity detection rate after microdissection. Thus, this work confirms the contribution of microdissection for loss of heterozygosity assessment.     

Pharmacokinetic interaction between high-dose methotrexate and oxacillin

An 18-year-old man received two high-dose methotrexate cycles for the treatment of an osteosarcoma. Fifteen grams of methotrexate were infused over 6 hours. During the second cycle, co-administration of oxacillin (1g/8h) resulted in prolonged and marked elevation of methotrexate plasma concentrations. The patient experienced acute toxicity with renal failure, myelosuppression, mucitis, fever, and dermatologic abnormalities. After an initial improvement with folinic acid rescue and hemodialysis, the patient died. Oxacillin may thus inhibit the elimination of methotrexate.     

Development and validation of a highly sensitive RIA for zoledronic acid,a new potent heterocyclic bisphosphonate,in human serum,plasma and urine

Zoledronic acid is a new, highly potent bisphosphonate drug under clinical evaluation. A radioimmunoassay has been developed to determine zoledronic acid concentration in human serum, plasma, and urine. The assay utilizes rabbit polyclonal antisera against a zoledronic acid-BSA conjugate and a [125I]zoledronic acid derivative as tracer in a competitive format adapted to microtiter plates. The assay shows a LLOQ 0.4 ng/ml in serum or plasma (interassay%CV=17%, accuracy 97%), 5 ng/ml in urine (21%, 98%). In 23 patients receiving 4, 8 or 16 mg of zoledronic acid, drug concentrations in plasma were dose proportional and showed a multiphasic profile, followed by a prolonged gradual decline to concentrations near the LLOQ. Zoledronic acid disposition in plasma and the recovery of only 40-50% of the dose in urine are consistent with the rapid and extensive uptake by and slow release from bone in parallel with renal clearance, typically shown by bisphosphonates.     

Hypermethylation of the human telomerase catalytic subunit (hTERT) gene correlates with telomerase activity

DNA methylation is an epigenetic process involved in embryonic development, differentiation and aging. It is 1 of the mechanisms resulting in gene silencing in carcinogenesis, especially in tumor suppressor genes (e.g., p16, Rb). Telomerase, the DNA polymerase adding TTAGGG repeats to the chromosome end, is involved in the regulation of the replicative life span by maintaining telomere length. This enzyme is activated in germ and stem cells, repressed in normal somatic cells and reactivated in a large majority of tumor cells. The promoter region of the hTERT gene, encoding for the catalytic subunit of human telomerase, has been located in a CpG island and may therefore be regulated at least in part by DNA methylation. We analyzed the methylation status of 27 CpG sites within the hTERT promoter core region by methylation-sensitive single-strand conformation analysis (MS-SSCA) and direct sequencing using bisulfite-modified DNA in 56 human tumor cell lines, as well as tumor and normal tissues from different organs. A positive correlation was observed among hypermethylation of the hTERT promoter, hTERT mRNA expression and telomerase activity (p < 0.00001). Furthermore, this correlation was confirmed in normal tissues where hypermethylation of the hTERT promoter was found exclusively in hTERT-expressing telomerase-positive samples and was absent in telomerase-negative samples (p < 0.00002). Since tumor tissues contain also nonneoplastic stromal elements, we performed microdissection to allow confirmation that the hTERT promoter methylation truly occurred in tumor cells. Our results suggest that methylation may be involved in the regulation of hTERT gene expression. To our knowledge, this is the first gene in which methylation of its promoter sequence has been found to be positively correlated with gene expression.     

Conservative management of malignant and borderline ovarian tumor

Conservative management of at least a part of one ovary and the uterus, in order to preserve fertility-potential, could be propose in most of patients with nonepithelial and borderline ovarian tumor. This conservative management could be performed even in patients with borderline ovarian tumor associated with noninvasive peritoneal implants (if complete resection of peritoneal disease). A removal of the preserved ovary after completion of the pregnancy(ies) is not necessary if patients agree to a careful follow-up procedure. In patient with epithelial ovarian cancer, conservative management could be performed only in case of young patients who desire to preserve fertility function with: unilateral tumor (stage IA), grade 1 (and 2?), who underwent an adequate staging surgery (including peritoneal washings, omentectomy, multiple peritoneal biopsies, uterine curettage and complete pelvic and paraaortic lymphadenectomy) and with a careful follow-up. A conservative management should not be performed in patients with tumor stage > IA and/or grade 3. Removal of preserved ovary should be performed after completion of pregnancy(ies) in order to reduce the risk of ovarian recurrence.     

Risk of pulmonary embolism after a negative spiral CT angiogram in patients with pulmonary disease: 1-year clinical follow-up study

PURPOSE: To evaluate the effect of pulmonary disease on diagnostic utility of spiral computed tomographic (CT) angiography in clinical practice. MATERIALS AND METHODS: Three hundred thirty-four patients, including 215 patients with pulmonary disease (group 1) and 119 patients with no history of respiratory disorder (group 2), were referred for thin-collimation CT angiography of the pulmonary circulation as the first-line diagnostic test. Patients with negative angiograms who had not received anticoagulation therapy and who could be clinically followed up at 3 months, 6 months, and 1 year were considered in the final study groups (n = 185); 135 patients had lung disease (group 3), and 50 patients had no history of a respiratory disorder (group 4). RESULTS: Between groups 3 and 4, no significant differences were found in the referral location, age, and risk factors. Confident evaluation of pulmonary arteries down to the subsegmental level was performed in 31 (23%) patients in group 3 and in 15 (30%) in group 4 (P =.5). Three episodes of acute pulmonary embolism (PE), all fatal, were diagnosed in group 3 patients; two cases occurred 14 days and one case occurred 6 months after the negative spiral CT scan. The negative predictive value of spiral CT angiography was 98% (175 of 178) in the study group in which follow-up was performed, with no significant difference between the values in groups 3 (98% [132 of 135]) and 4 (100% [50 of 50]). CONCLUSION: Underlying respiratory disease does not affect the negative predictive value of thin-collimation CT angiography, which appears to be a reliable tool in the work-up in this subgroup of patients with acute PE.