Armando Rodríguez

Genomic DNA repeat from Leishmania (Viannia) braziliensis (Venezuelan strain) containing simple repeats and microsatellites

In this paper the Leishmania (Viannia) braziliensis complex is defined as containing all species of the actual subgenus Viannia. Organisms of the L. (V) braziliensis complex are the causative agents of localized human cutaneous and mucocutaneous leishmaniasis in South America, much of Central America and some ares of North America. In our search for better species and subspecies diagnostic probes we focused our research on repetitive DNA, since it provides a greater number of target sites for hybridization. In this work we report the isolation and sequencing of a 1.8 kb DNA region, LbJ38, which is probably tandemly repeated or dispersed at least 4 times along one chromosome and is naturally present in L. (V) braziliensis genomic DNA. This region contains microsatellites and simple repeat DNA sequences and was isolated by screening a genomic DNA cosmid library with complex- and species-specific probes. No homology was found with other Leishmania microsatellite or repetitive DNA. The utility of this repetitive sequence and primers derived from it in the identification of L. (V) braziliensis is demonstrated. As far as we are aware, this is the first report of sequence characterized repetitive microsatellite and GC rich simple repeat DNA from the nuclear genome of New World Leishmania.

Cotton Rats (Sigmodon hispidus) and Black Rats (Rattus rattus) as Possible Reservoirs of Leishmania spp. in Lara State, Venezuela

A total of 519 wild animals belonging to eleven species were collected during a two year study in a cutaneous leishmaniasis endemic area in Venezuela (La Matica, Lara State). The animals were captured in home-made Tomahawk-like traps baited with maize, bananas or other available local fruits, and parasites were isolated from 27 specimens. Two different species were found naturally infected with flagellates, i.e., cotton rats (Sigmodon hispidus) and black rats (Rattus rattus). Characterization of the parasites using PCR, kDNA restriction pattern and hybridization with species-specific probes revealed the presence of Leishmania (L.) mexicana in three of the black rats and Leishmania (V.) braziliensis in two others. The latter species was also identified in the single positive specimen of S. hispidus. The results suggested both species of animals as possible reservoirs of Leishmania sp.

Molecular epidemiology of cutaneous leishmaniasis in Venezuela

This paper discusses the utility of a set of primers (3J1, 3J2) designed from a repetitive nuclear deoxyribonucleic acid sequence for the diagnosis of Leishmania braziliensis infection in samples obtained from humans, insect vectors and mammalian reservoir hosts from different endemic areas in Venezuela. A high incidence of Leishmania (Viannia) braziliensis infection was found in the endemic areas studied. The sensitivity and specificity of the primers used were adequate for the identification of the natural vectors and reservoir hosts of L. (V.) braziliensis. The polymerase chain reaction was more sensitive than culture and stained smear examination in the diagnosis of cutaneous leishmaniasis, detecting 80% of cases compared to 42% and 72%, respectively.

Métodos utilizados en la identificación del virus de papiloma humano

Given the causal relationship between specific types of HPV with cervical cancer and precursor lesions, it is important to identify the viral type involved. The characterization is done by various methods that vary in sensitivity and specificity, whose use depends mainly on the aim pursued and the characteristics of the evaluated sample. HPV typing is not only important clinically for the establishment of monitoring and treatment of a patient, it also provides knowledge of the viral types circulating in a population, which is of interest in the development of prevention and treatment programs for this disease. This paper is a review of methods used in the detection and identification of HPV in cervical cancer lesions, highlighting their sensitivity and specificity.

Second cancers in patients with head and neck carcinoma: Prognostic factors

Background. The occurrence of a second tumor in patients with squamous cell carcinoma of the head and neck (HNCA) exceeds that expected in the general population. The purpose of this study was to determine the predictive factors associated with the development of a second cancer in these patients. Methods. We identified 381 patients with HNCA treated between 1992 and 2011 at the University Hospital of Salamanca. Of these, 36 developed a second tumor. We included demographic, clinical and tumor characteristics and examined their relationship to the diagnosis of a second tumor. For this we conducted a univariate and multivariate analysis. We used the method of Cox proportional hazards (Forward stepwise) multivariate analysis. A p value less than or equal to 0.05 was considered statistically significant. The analysis was performed using SPSS 12.0. Results. Approximately 11% (36/321) of patients developed a second cancer during follow-up. 69.4% (25/35) of second tumors involving the supradiaphragmatic aerodigestive tract and lungs. 51.4% (18/35) was squamous cell histology. The median followup of patients with a second tumor was 23.93 months (interquartile range = 49). 80% (24/30) developed a new malignancy after 12 months. Both univariate and multivariate analysis, the variable that was significantly associated with the occurrence of second malignancies was duration of neoadjuvant chemotherapy. In multivariate analysis, we found that the variables age (HR = 1.490, p = 0.14) and duration of neoadjuvant chemotherapy (HR = 1.655, p = 0.001) were associated with the development of a second malignancy. Conclusions. The results suggest that patients with HNCA have an increased risk of a second tumor mainly upper aerodigestive tract and lung. Multivariate analysis confirmed a model of two risk factors for the development of the second tumor: age (HR = 1.490, p = 0.014) and the duration of neoadjuvant chemotherapy (HR = 1.655, p = .001).