Host-plant sex and phenology of Buddleja cordata Kunth interact to influence arthropod communities.

Intraspecific variation in plants is expected to have profound impacts on the arthropod communities associated with them. Because sexual dimorphism in plants is expected to provide consistent variation among individuals of the same species, researchers have often studied the effect it has on associated arthropods. Nevertheless, most studies have focused on the effect of sexual dimorphism in a single or a few herbivores, thus overlooking the potential effects on the whole arthropod community. Our main objective was to evaluate effects of Buddleja cordata's plant-sex on its associated arthropod community. We surveyed 13 pairs of male and female plants every 2 months during a year (June 2010 to April 2011). Every sampling date, we measured plant traits (water content and leaf thickness), herbivory, and the arthropod community. We did not find differences in herbivory between plant sex or through time. However, we found differences in water content through time, with leaf water-content matching the environmental seasonality. For arthropod richness, we found 68 morphospecies associated with female and 72 with male plants, from which 53 were shared by both sexes. We did not observe differences in morphospecies richness; however, we found sex-associated differences in the diversity of all species and differences on the diversity of the most abundant species with an interesting temporal component. During peak flowering season, male plants showed higher values on both parameters, but during the peak fructification season female plants showed the higher values on both diversity parameters. Our research exemplifies the interaction between plant-phenology and plant-sex as drivers of arthropod communities' diversity, even when plant sexual-dimorphism is inconspicuous, and highlighting the importance of accounting for seasonal variation. We stress the need of conducting more studies that test this time-dependent framework in other dioecious systems, as it has the potential to reconcile previous contrasting observations reported in the literature.

In Silico Studies Most Employed in the Discovery of New Antimicrobial Agents.

The present review summarizes the methods most used in drug search and design, which may help to keep pace with the growing antibiotic resistance among pathogens. The rate of reduction in the effectiveness of many antimicrobial medications, caused by this resistance, is faster than new drug development, thereby creating a worldwide public health threat. Among the scientific community, the urgency of finding new drugs is peaking interest in the use of in silico studies to explore the interaction of compounds with target receptors. With this approach, small molecules (designed or retrieved from data bases) are tested with computer-aided molecular simulation to explore their efficacy. That is, ligand-protein complexes are constructed and evaluated via virtual screening (VS), molecular dynamics (MD), and docking simulations with the data from the physical, chemical and pharmacological properties of such molecules. Additionally, the application of quantitative structure-activity relationship (QSAR), multi-target quantitative structure-activity relationship (mt- QSAR), and multi-tasking quantitative structure-biological effect (mtk-QSBER) can be enhanced by principal component analysis and systematic workflows. These types of studies aid in selecting a group of promising molecules with high potency and selectivity as well as low toxicity, thus making in vitro and in vivo (animal model) testing more efficient. Since knowledge of the receptor topography and receptor-ligand interactions has yielded promising compounds and effective drugs, there is now no doubt that the use of in silico tools can lead to more rapid validation of new potential drugs for preclinical studies and clinical trials.

Histones and long non-coding RNAs: the new insights of epigenetic deregulation involved in oral cancer.

Oral squamous cell carcinoma (OSCC) is a category of aggressive malignancies that represent clinically, molecularly, and etiologically heterogeneous tumors. The majority of OSCCs are associated with tobacco and alcohol use, acting both independently and synergistically, which suggests that the environment plays an important role in carcinogenesis; however, the mechanisms associated with the development of OSCC are not well understood. It has been proposed that the epigenetic components could be implicated in the initiation and progression of OSCC. Primarily, aberrant DNA methylation patterns have been widely addressed in the study of OSCC. Diverse studies have proposed that other epigenetic processes such as post-translational histone modification, the deposition of histone variants, histone chaperones, and recently non-coding RNA, can be also involved in the development of oral cancer. In this review we focus on describing the new insights of the epigenetics processes that are related with OSCC as histones variants and long non-coding RNAs.

Association between age and high-risk human papilloma virus in Mexican oral cancer patients.

OBJECTIVE: Studies reporting low prevalence of HPV in OSCC with declining age at presentation are increasing. The aim of this study was to determine the prevalence of HPV in a group of OSCC cases and controls in a Mexican population. METHODS: The matched case-control study included 80 OSCC cases and 320 controls. HPV/DNA presence was evaluated through PCR amplification using three sets of consensus primers for the L1 gene. A conditional logistic regression analysis was carried out for the matched OSCC cases and controls. Interactions between risk factors and OCSS were tested in the construction process of the models. RESULTS: HPV prevalence was 5% in OSCC cases and 2.5% in controls. HPV-detected types were 16, 18 and 56. According to conditional logistics regression model, an association was detected between HR-HPV and OSCC. All HR-HPV-positive OSCC cases corresponded to young patients (<45 years), non-smokers and non-alcohol drinkers. CONCLUSIONS: The HR-HPV can be a contributing factor to oral carcinogenesis, especially in younger individuals without known risk factors such as tobacco and alcohol.

Alternating chemotherapy: gemcitabine and cisplatin with concurrent radiotherapy for treatment of advanced head and neck cancer.

BACKGROUND: Many studies have shown gemcitabine and cisplatin are radiosensitizers. Concurrent chemoradiation seems to be an efficient approach for treatment of advanced head and neck cancer (HNC), but toxicity is significant. OBJECTIVE: To evaluate safety and explore efficacy of alternating chemotherapy with gemcitabine and cisplatin concurrent with radiotherapy in patients with advanced non-metastatic HNC. PATIENTS AND METHODS: Twenty-eight patients diagnosed with advanced Squamous Cell Carcinomas of the Head and Neck (SCCHN) in stages III (28%), IVa (36%), and IVb (36%) were treated with gemcitabine: 100mg/m(2) alternating with cisplatin: 50mg/m(2) concurrent with radiotherapy at doses of 2 Gy/day until completing 70 Gy. While awaiting for concurrent treatment, eleven patients received induction chemotherapy with cisplatin: 100mg/m(2) and 5-FU: 1000 mg/m(2). Toxicity, especially in relation to mucositis, xerostomy, dysphagia, leucopenia and radiodermitis was evaluated. RESULTS: 5-year progression-free survival was 27.8 ± 17.2% (CI-95: 0-61.5) and overall survival was 55.9 ± 11% (CI: 34.4-77.5). Overall response rate was 93%; complete response was 64.3% and partial response was 28.6%. Extensive surgery for primary site was avoided in 19 patients (70.4%). Grade 3-4 adverse events were mucositis (46.4%), leucopenia (14.2%), dysphagia (25%), xerostomy (10.7%) and radiodermitis (3.6%). Response rates and toxicity were not significantly different among those patients with and without induction chemotherapy, but survival was higher in patients receiving induction. CONCLUSIONS: Gemcitabine alternating with cisplatin concurrent with radiotherapy is an active and safe treatment that deserves further study.

DNA methylation in oral squamous cell carcinoma: molecular mechanisms and clinical implications.

DNA methylation is an important regulator of gene transcription, and its role in carcinogenesis has been a topic of considerable interest in the last few years. Of the all epigenetic modifications, methylation, which represses transcription of the promoter region of tumor suppressor genes leading to gene silencing, has been most extensively studied. Oral squamous cell carcinoma (OSCC) has long been known to be the endpoint of many genetic changes, not only genomic mutations but also abnormal epigenetic modifications, as such, promoter methylation, contribute to development of this tumors. Recent studies have shown that promoter methylation of tumor suppressor genes is an important factor in carcinogenesis of OSCC. Some of the main genes that frequently showed promoter methylation in OSCC are those that participate in diverse processes such as regulation of the cell cycle, DNA repair, proliferation, and apoptosis. The aim of this review is to assess the current state of knowledge regarding promoter methylation of diverse genes in OSCC.

hMLH1 promoter methylation is an early event in oral cancer.

Promoter methylation is believed to inactivate the expression of hMLH1. This process has been implicated in the tumorigenesis of oral squamous cell carcinoma (OSCC). Thus, the aim of this study was to determine the profile of hMLH1 methylation and protein expression in OSCC. The matched case-control study included 50 OSCC cases and 200 controls, with a median of age 64 (Q1-Q3 54-71) years. Protein expression was determined by immunohistochemical staining, and hMLH1 gene promoter methylation was analyzed by methylation-specific polymerase chain reaction (MSP). A conditional logistic regression model for risk factors was built for OSCC cases and matched controls. Promoter methylation of hMLH1 was detected in 38 (76%) OSCC cases, but in none of the control samples. Of the 38 OSCC samples with promoter methylation, 12 (32%) were negative for hMLH1 protein, and corresponded to early clinical stages (10 in stage II and 2 in stage I). All 12 unmethylated samples showed positive stain for hMLH1. Multiple logistic regression analysis showed an OR of 16.54 (IC 95%: 1.69-161.68, p=0.016) for methylation of the hMLH1 gene and early stages of OSCC, adjusting by gender and tobacco use. This study showed a high frequency of hMLH1 promoter methylation that occurred in most of the early stage cases and in about half of the late stage cases. It is proposed that hMLH1 promoter methylation is an early event that is maintained during tumor progression.

Identification of oral candidosis, hairy leukoplakia and recurrent oral ulcers as distinct cases of immune reconstitution inflammatory syndrome.

Oral lesions such as candidosis, hairy leukoplakia (HL) and oral ulcers are strikingly absent in the numerous reports of immune reconstitution inflammatory syndrome (IRIS). To document oral manifestations attributable to immune reconstitution, we conducted a longitudinal follow-up of a cohort of HIV+ individuals starting highly active antiretroviral therapy (HAART) and completing oral pathology follow-up up to 12 weeks after treatment initiation. HIV-infected patients had oral examinations, CD4+ T-cell count and viral load determinations performed at baseline, and at weeks 4, 8 and 12 after HAART initiation. Among individuals with satisfactory viral response and recovery of > or =50 CD4+ T-cell/microL, eight patients complied with strict IRIS criteria: two developed clinical signs of oral candidosis (OC), two oral ulcers, three HL and one Kaposi's sarcoma. CD4+ T-cell counts at symptom onset suggested no remaining immune suppression. Our findings show that cases of OC, HL and recurrent ulcers can be instances of IRIS.

Clinical, histological and immunohistochemical findings in oral Kaposi's sarcoma in a series of Mexican AIDS patients. Comparative study.

BACKGROUND: The origin of spindle cells (SC) in oral Kaposi's sarcoma (OKS) is still an intriguing aspect. Thus the aim of the present study was to compare the clinical, histological and immunohistochemical characteristics of OKS and oral pyogenic granuloma (OPG), in order to contribute to the knowledge of the cells involved in Kaposi's sarcoma pathogenesis. METHODS: In this retrospective, observational and comparative study, 39 OKS and 30 OPG cases were included. Immunohistochemical studies were performed for vimentin, alpha SMA, desmin, C-kit, CD34, D2-40 and LANA-1 [human herpesvirus-8(HHV-8)]. Statistical comparisons were done using the chi-square and Wilcoxon-Mann-Whitney rank sum tests. RESULTS: Fourteen (35.9%) OKS cases also affected the skin, and 83.8% involved the palate. All OKS and OPG were positive for vimentin and CD34. OKS samples were positive for alpha SMA, and 25.6% expressed C-kit. All OKS cases were positive for HHV-8, and the number of positive cells increased significantly from early / intermediate to late histological stage. D2-40 was expressed in the cellular component and vascular walls of all OKS cases, but it was negative in OPG. HHV-8 expression was increased in late histological stages of OKS lesions. CONCLUSIONS: The expression of D2-40 marker in the vascular walls and SC supports the view of a lymphatic differentiation in neoplastic cells of OKS. Desmin, alpha SMA, D2-40, C-kit and HHV-8 were the main markers differently expressed in OKS and OPG.