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Federico García

Publications and source records attributed to Federico García.

5 recordsLinked to original sources
PubMed2006

mtDNA microevolution in Southern Chile's archipelagos.

The genetic variability of four predominantly Indian populations of southern Chile's archipelagos was examined by determining the frequencies of four mitochondrial DNA haplogroups that characterize the American Indian populations. Over 90% of the individuals analyzed presented Native American mtDNA haplogroups. By means of an unweighted group pair method with arithmetic mean (UPGMA) dendrogram, a principal component analysis (PCA) derived from a distance matrix of mtDNA, and the exact test of population differentiation, we are able to prove the existence of a North-South cline. The populations in the northern part of the archipelagos are genetically similar to the Huilliche tribe, while the groups from the South are most closely related to the Fueguino tribe from the extreme South of Chile, and secondarily to the Pehuenche and Mapuche, who are found to the North and East of Chiloé archipelago. These results are consistent with a colonization of the southern archipelagos from Tierra del Fuego. We evaluate the evolutionary relationships of the population of the Chiloé area to groups from other geographic areas of Chile, using analysis of molecular variance (AMOVA). Three Amerindian clusters are identified: one formed by the Aymará and Atacameño, a second by the Huilliche, and a third including the Mapuche, Pehuenche, and Fueguino tribes, and the population inhabiting the South of the Chiloé arcipelago. These groups exhibit a North-South gradient in the frequency of haplogroup B, confirmed by F(ST) tests.

Chile↗
PubMed2005

Impact of drug resistance genotypes on CD4+ counts and plasma viremia in heavily antiretroviral-experienced HIV-infected patients.

The number of HIV-infected individuals with prior multiple treatment failures is increasing as time passes by. The success of antiretroviral therapy in these patients is often compromised by the selection of drug-resistant viruses. Despite initial concerns, a rebound in AIDS cases among heavily treatment-experienced patients failing virologically their antiretroviral therapy has not occurred yet. In a multicenter study conducted in Spain, HIV-infected patients were assessed with prior failure to antiretrovirals from the three main drug families who presented during the last semester of the year 2003 with plasma HIV-RNA values above 1,000 copies/ml, despite good treatment adherence. The relationships between CD4+ T cell counts, viral loads and drug-resistant genotypes were examined. A total of 273 patients were identified in 12 centers (78% male, median age: 41 years). The mean viral load was 50,438 copies/ml and the mean CD4+ count was 328 cells/mul. Only 19.5% had less than 200 CD4+ T cells/mul. Most patients (95%) were receiving nucleoside reverse transcriptase inhibitors (NRTI) in their last antiretroviral regimen, while 63% were treated with protease inhibitors (PI) and 27% on non-nucleoside reverse transcriptase inhibitors (NNRTI). Overall, 97.4% had at least one drug resistance mutation (87.2% for NRTI, 68.5% for NNRTI, and 92.7% for PI). Using the virtual phenotype, resistance to three or more drugs within each class was recognized in 45.8% for NRTI, 40.7% for NNRTI, and 44.7% for PI. Moreover, cross-resistance to compounds from two or three drug families was recognized in 41% and 19.4% of patients, respectively. Nearly half of the patients had plasma HIV-RNA below 10,000 copies/ml and they showed significantly higher CD4 + counts than those with greater viremia (408 versus 259 cells/mul; P < 0.001). Patients with higher plasma viremia had significantly more drug resistance mutations than those with lower viremia. No favorable effect on viral load could be recognized for individual drug resistance mutations known to reduce viral fitness in vitro (i.e., rtM184V, rtL74V, rtK65R, proD30N, or proI50L). In summary, a large proportion of treatment-experienced patients failing their current antiretroviral regimen carry viruses with broad cross-resistant genotypes. Nearly half of the patients with these multi-drug resistant viruses had < 10,000 HIV-RNA copies/ml and 80% have more than 200 CD4 + T cells/mul. Thus, maintaining treatment HIV-infected individuals failing virologically and harboring drug-resistant viruses might ameliorate immunological deterioration until new drugs became available. J. Med. Virol. 77:23-28, 2005. (c) 2005 Wiley-Liss, Inc.

Adult↗
PubMed2003

Introduction of HIV type 1 non-B subtypes into Eastern Andalusia through immigration.

A study of the distribution of HIV-1 subtypes in the native and immigrant populations of Eastern Andalusia (Southern Spain) was conducted to determine any changes between 1983 and 2001 and to identify antiretroviral resistance mutations in non-B subtype strains among the immigrant population. The study included 111 native patients from Eastern Andalusia: 94 infected with HIV before 1996 and 17 infected since 1996. A parallel study was conducted on 26 HIV-positive immigrants from Africa. Subtyping was done with the heteroduplex mobility assay. Resistance mutations were determined by line probe assay. A total of 137 patients were studied: 9.2% had subtype A (n = 12), 80.8% subtype B (n = 105), and 1.5% subtype C (n = 2). Among the Eastern Andalusia population infected before 1996, 10.9% had non-B subtypes, compared with 23.5% of those infected after that year. The greatest percentage of non-B subtypes (52.4%) was found among the immigrant population. Resistance mutation K70R was detected in one of the six immigrants with non-B subtype and M41L in another. There has been a slight increase in the diversity of HIV-1 subtypes in Eastern Andalusia over the past few years, possibly influenced by non-B subtypes introduced by immigrants from sub-Saharan Africa.

Adult↗