Evaluation of the safety and adjuvant effect of a detoxified listeriolysin O mutant on the humoral response to dengue virus antigens

Listeriolysin O (LLO) has been proposed as a potential carrier or adjuvant molecule in the vaccination field. However, the cytotoxic and pro-apoptotic effects of LLO are the major limitations for this purpose. Here, we have performed a preclinical safety evaluation and characterized a new potential adjuvant application for a non-cytolytic LLO mutant (dtLLO) to enhance and modulate the immune response against the envelope (E) protein from dengue virus. In addition, we have studied the adjuvant effects of dtLLO on human immune cells and the role of membrane cholesterol for the binding and proinflammatory property of the toxoid. Our in-vivo results in the murine model confirmed that dtLLO is a safer molecule than wild-type LLO (wtLLO), with a significantly increased survival rate for mice challenged with dtLLO compared with mice challenged with wtLLO (P < 0·001). Histopathological analysis showed non-toxic effects in key target organs such as brain, heart, liver, spleen, kidney and lung after challenge with dtLLO. In vitro, dtLLO retained the capacity of binding to plasma membrane cholesterol on the surface of murine and human immune cells. Immunization of 6-8-week-old female BALB/c mice with a combination of dtLLO mixed with E protein elicited a robust specific humoral response with isotype diversification of immunoglobulin (Ig)G antibodies (IgG1 and IgG2a). Finally, we demonstrated that cholesterol and lipid raft integrity are required to induce a proinflammatory response by human cells. Taken together, these findings support a potential use of the dtLLO mutant as a safe and effective adjuvant molecule in vaccination.

[Primary lymphoma of the central nervous system: 20 years' experience in a referral hospital]

INTRODUCTION

Primary central nervous system lymphomas (PCNSL) are rare neoplasms. AIM. To study the clinical aspects and the immuno-phenotype of all cases of PCNSL in a 20 years lapse in a referral hospital in Northeastern Mexico.

PATIENTS AND METHODS

From January 1986 to December 2005 all PCNSL histologically confirmed were studied.

RESULTS

The primary lymphomas were 1% of malignant central nervous system neoplasms. 21 cases were studied (ages from 9-70 years) with male predominance (2:1). 24% patients had immuno-suppression. The more frequent clinical data were: papilledema (71%), headache (62%), paresis (48%) and seizures (33%). 33% of patients died during the first six months after diagnosis. The T lymphomas were 19% of cases and corresponded to small cell type.

CONCLUSIONS

PCNSL are still a diagnostic challenge. Multicenter studies are required in order to determine the best treatment protocol.

[A case of Creutzfeldt-Jakob in the Mexican north-east and review of current concepts on prion disease]

The case reported here is that of a 50-year-old man from Saltillo, Coahuila, Mexico, who during the previous 15 months developed a demential syndrome and myoclonia. The brain biopsy led to establish a diagnosis of spongiform encephalopathy. The EEG showed periodic sharp wave complexes over the right hemisphere. A review on about prion diseases is included.

[Cranial metastasis of thyroid follicular carcinoma. Report of a case]

Thyroid follicular carcinoma is able to produce metastatic lesions before the vanishing of the primary lesion. We present a case of a woman with a lytic, solitary, asymptomatic parietal bone lesion of 2 years of evolution. Autopsy revealed a thyroid gland with two small cystic areas and renal metastasis. Thyroid carcinoma should be included in the differential diagnosis in cases of lytic bone lesions with long evolution in patients 60 years of age or older.

[Breast cancer genetics. BRCA1 and BRCA2: the main genes for disease predisposition]

Breast cancer is among the most common world cancers. In Mexico this neoplasm has been progressively increasing since 1990 and is expected to continue. The risk factors for this disease are age, some reproductive factors, ionizing radiation, contraceptives, obesity and high fat diets, among other factors. The main risk factor for BC is a positive family history. Several families, in which clustering but no mendelian inheritance exists, the BC is due probably to mutations in low penetrance genes and/or environmental factors. In families with autosomal dominant trait, the BRCA1 and BRCA2 genes are frequently mutated. These genes are the two main BC susceptibility genes. BRCA1 predispose to BC and ovarian cancer, while BRCA2 mutations predispose to BC in men and women. Both are long genes, tumor suppressors, functioning in a cell cycle dependent manner, and it is believed that both switch on the transcription of several genes, and participate in DNA repair. The mutations profile of these genes is known in developed countries, while in Latin America their search has just began. A multidisciplinary group most be responsible of the clinical management of patients with mutations in BRCA1 and BRCA2, and the risk assignment and Genetic counseling most be done carefully.

[677T mutation of the MTHFR gene in adenomas and colorectal cancer in a population sample from the Northeastern Mexico. Preliminary results]

INTRODUCTION

Adequate intake of folates has been associated to low prevalence of colon cancer. Methylenetetrahydrofolate reductase enzyme (MTHFR) plays an important role in folate metabolism. The role of the 677 mutation at the MTHFR gene in the risk for colorectal cancer remains controversial. A recent report established that this mutation has a high prevalence in the healthy Mexican population.

AIMS

To analyze the prevalence of 677T MTHFR mutation in patients with colorectal cancer and controls without chronic gastrointestinal disorders.

METHODS

Seventy-four colorectal cancer, 32 adenomas and 110 normal samples were analyzed. Patients and controls were matched for sex and age. For each sample, DNA isolation, PCR, and mutation detection by restriction enzyme digestion were performed to determine the allele at the 677 position in the MTHFR gene.

RESULTS

Genotype 677C/677C was found in 18.7, 20.3, and 30.9% in adenomas, cancer lesions and controls, respectively. Frequencies of the 677C/677T genotype were 59.4, 56.7, and 47.3%, in adenomas, cancer lesions, and controls, respectively. Genotype 677T/677T was found in 21.9, 23.0, and 21.8% in adenomas, cancer lesions, and controls, respectively. The odds ratio between genotypes carrying the mutation (T/T and C/T) and normal genotype (CC) was 1.81 (IC 95% 0.97-3.3), chi 2 = 3.5, p = 0.06.

CONCLUSION

Our results showed that persons who carry the 677T mutation at MTHFR locus have a tendency for an increased risk for colorectal cancer. This study supports the basic concept that low levels of folic acid contribute with the colorectal cancer pathogenesis. Our lack of statistic significance may be due to reduced sample size.

[External progressive ophthalmoplegia secondary to mitochondrial myopathy. Report of a case and review of the literature]

Progressive limitation of occular motility, accompanied by ptosis but usually without diplopia, occurs in many pathologic states, including mitochondrial diseases. A case with chronic progressive external ophthalmoplegia with onset during childhood, associated with proximal myopathy and dysphasia is presented. The muscle biopsy showed a myopathic pattern and abnormal subsarcolemmal mitochondrial deposits. Muscle biopsy for important in the correct diagnosis of this entity.

Risk factors of breast cancer in Mexican women

OBJECTIVE

To investigate the association between family history (FH) of neoplasia, gyneco-obstetric factors and breast cancer (BC) in a case-control study. In cases, to analyze those variables in relation with early onset of BC, the manner of detection (self-examination, prompted by pain, or casual), the size of tumor, and the elapsed time to seek medical attention.

MATERIAL AND METHODS

Data from 151 prevalent BC cases and 235 age-matched controls were analyzed by multiple logistic regression, to assess the influence of BC risk factors.

RESULTS

Ten per cent of patients and 1% of controls had first-degree relatives (FDR) with BC. Family history of FDR with BC (OR, 11.2; 95% CI 2.42-51.92) or with gastric or pancreatic cancer (OR, 17.7; 95% CI 2.2-142.6) was associated with BC risk. Breastfeeding at or under 25 years of age was protective against BC (OR, 0.40; 95% CI 0.24-0.66). The manner of tumor detection did not influence its size at the time of diagnosis.

CONCLUSIONS

Our study confirms that FH of BC and/or of gastric or pancreatic carcinoma are risk factors for BC, while lactation at 25 years of age or earlier is protective.

[Cystic lymphangioma of the ileum. A case report]

Cystic lymphangioma is an uncommon tumor of the small bowel. A case in the ileum in a 3 years old boy is described. The clinical picture was with 10 months of progression with constipation, abdominal pain associated with meals and finally an acute abdomen suggestive of appendicitis. A conservative surgical treatment with segmental intestinal resection and termino-terminal anastomosis was curative. The anatomopathological findings are described and a revision of the literature is done.