Zostera noltei response to transplantation into historically Hg-contaminated sediments (A mesocosm experiment): Growth, bioaccumulation and photosynthetic performance

The present study aimed to evaluate the effectiveness of seagrass recolonization as a nature-based solution for the recovery of a coastal area historically contaminated by mercury (Laranjo Bay, Ria de Aveiro, Portugal). A mesocosm approach was employed to assess the resistance of Zostera noltei to transplantation into contaminated sediments collected in-situ (0.5-20 mg kg^-1 Hg). At each sampling time (15, 30, 60, 120 and 210 days), the resistance of transplanted Z. noltei was evaluated through growth parameters (biomass and coverage area), photosynthetic performance and elemental composition. Although some significant differences (p ≤ 0.05) were observed between treatments, essentially associated with the elemental composition of plant tissues, the most relevant variations were associated with seasonality. Overall, plants were found to not be affected by sediment contamination, under the tested concentrations, suggesting that recolonization with Z. noltei can be an effective restoration strategy for historically contaminated coastal areas.

Brief Report: Young Age and Sex Work Are Associated With HIV Seroconversion Among Transgender Women in São Paulo, Brazil

BACKGROUND

Transgender women worldwide have the highest prevalence of HIV and the lowest access to prevention among groups at risk of HIV. However, few longitudinal studies have directly measured HIV incidence and identified predictors of HIV acquisition among transgender women.

SETTING

São Paulo, Latin America's largest city.

METHODS

We conducted a longitudinal study among transgender women in São Paulo. Participants were recruited by a long-chain peer referral process from May 2017 to July 2019. Those aged 18 years and older and who were HIV-negative at baseline were retested every 6 months up to 18 months. HIV incidence was calculated by dividing the number of seroconversions by the person-years (PYs) of follow-up; 95% confidence intervals (CIs) were constructed assuming a Poisson distribution. Conditional maximum likelihood ratios assessed differences in HIV incidence by risk factors.

RESULTS

A racially/ethnically diverse sample of 545 HIV-negative transgender women was enrolled. In 485.5 PYs of follow-up, 13 seroconversions were observed, yielding an incidence of 2.68 per 100 PYs (95% CI: 1.43 to 4.58). HIV incidence was significantly higher among transgender women aged 18-24 years (rate ratio 3.85, 95% CI: 1.24 to 12.93) and among those who engaged in sex work in the preceding month (rate ratio 5.90, 95% CI: 1.71 to 26.62).

CONCLUSIONS

HIV transmission continues at a high rate among transgender women in Brazil. Factors such as young age, lower level of education, and limited employment opportunities may lead to dependence on sex work that in turn increases HIV risk. Transgender-friendly prevention services, particularly programs delivering pre-exposure prophylaxis, are urgently needed.

Caries prevalence and treatment needs in young people in Portugal: the third national study

OBJECTIVE

To evaluate caries prevalence and dental treatment needs in Portuguese children and teenagers, as well as fluorosis prevalence in 12-year-old children, in order to address public oral health program strategies.

PARTICIPANTS

A representative stratified random cluster sample of 3,710 participants of 6, 12, and 18 years old was selected. A questionnaire was applied to determine sociodemographic data and some oral health determinants. The clinical examination was based on the ICDAS criteria, then adapted to DMFS index, and Dean's index for fluorosis.

RESULTS

Caries prevalence at 6, 12, and 18 years old was 45.2%, 47.0%, and 67.6%, respectively. D₅MFT scores were 1.18 (SD 0.06) and 2.51 (SD 0.10), respectively. Treatment needs at 12 and 18 years old were associated with 0.37 (SD 0.03) and 0.75 (SD 0.06) values in the "decayed" (D₅) variable. SiC index at 12 years old was 2.68 (SD 1.68). Sealants were identified in 55% of 12-year-old children and the mean of sealants per individual was 3.61; also, moderate (2.2%) and severe (0.2%) levels of fluorosis were detected.

CONCLUSIONS

The oral health situation in Portugal is favorable for young people, resulting in low treatment needs. The National Oral Health Promotion Program should be extended to include 18-year-olds.

Telomerase variant A279T induces telomere dysfunction and inhibits non-canonical telomerase activity in esophageal carcinomas

BACKGROUND

Although implicated in the pathogenesis of several chronic inflammatory disorders and hematologic malignancies, telomerase mutations have not been thoroughly characterized in human cancers. The present study was performed to examine the frequency and potential clinical relevance of telomerase mutations in esophageal carcinomas.

METHODS

Sequencing techniques were used to evaluate mutational status of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) in neoplastic and adjacent normal mucosa from 143 esophageal cancer (EsC) patients. MTS, flow cytometry, time lapse microscopy, and murine xenograft techniques were used to assess proliferation, apoptosis, chemotaxis, and tumorigenicity of EsC cells expressing either wtTERT or TERT variants. Immunoprecipitation, immunoblot, immunofluorescence, promoter-reporter and qRT-PCR techniques were used to evaluate interactions of TERT and several TERT variants with BRG-1 and β-catenin, and to assess expression of cytoskeletal proteins, and cell signaling. Fluorescence in-situ hybridization and spectral karyotyping techniques were used to examine telomere length and chromosomal stability.

RESULTS

Sequencing analysis revealed one deletion involving TERC (TERC del 341-360), and two non-synonymous TERT variants [A279T (2 homozygous, 9 heterozygous); A1062T (4 heterozygous)]. The minor allele frequency of the A279T variant was five-fold higher in EsC patients compared to healthy blood donors (p<0.01). Relative to wtTERT, A279T decreased telomere length, destabilized TERT-BRG-1-β-catenin complex, markedly depleted β-catenin, and down-regulated canonical Wnt signaling in cancer cells; these phenomena coincided with decreased proliferation, depletion of additional cytoskeletal proteins, impaired chemotaxis, increased chemosensitivity, and significantly decreased tumorigenicity of EsC cells. A279T expression significantly increased chromosomal aberrations in mouse embryonic fibroblasts (MEFs) following Zeocin™ exposure, as well as Li Fraumeni fibroblasts in the absence of pharmacologically-induced DNA damage.

CONCLUSIONS

A279T induces telomere dysfunction and inhibits non-canonical telomerase activity in esophageal cancer cells. These findings warrant further analysis of A279T expression in esophageal cancers and premalignant esophageal lesions.

Telomeres in disease

Telomeres and telomere repair are basic molecular features of cells possessing linear DNA chromosomes and defects in them result in various diseases. This review examines recent advances in understanding these diseases, particularly at a molecular level, and in relating telomere dysfunction to clinical diseases. We also discuss the potential role of telomere elongation as a therapy in diseases, and more controversially, the prevention/reversal of aging.

Abstract 1234: Development of a quick sensitive real-time PCR assay for measuring telomere length

Telomeres are the ends of linear chromosomes with tandem hexameric nucleotide repeats. Its function is to protect the natural ends of chromosomes from being recognized as damaged DNA, hence contributing to chromosomal stability. Telomeric sequences shorten each time the DNA replicates; when the telomere shrinks to a certain threshold, the cell can no longer divide. Its metabolism slows down, the cell ages, and dies. This molecular clock mechanism is also associated with cancer progression and therapy. Turning off telomerase activity by shutting off telomerase activation in cancer cells will led to cellular senescence. The current gold standard method to measuring telomere length is by Southern blot; however, it is tedious and costly, and often takes up to two days to complete. Here, we describe a new, simplified automated real-time PCR assay to accurately detect the abundance of these 5’-TTAGGG-3’nucleotide repeats and determine frequency and the length of Telomere in 47 min.

The assay demonstrated to be highly reproducible and accurate for human peripheral cells.

The result has good correlation of R2=0.9939, slope=3.41, sensitivity to 1ng of gDNA and has an amplification efficiency of 100%. We evaluated this assay with 299 healthy human subjects to date ranging from 0 (core blood) to 99-year of age. The results are positive with an inverse correlation between telomere length and age, as telomeres were shorter with aging. The telomere length was measured in 13 samples using the gold standard Southern blot method and the new q-PCR method (R2 = 0.8623), significantly higher than the originally described (Cawthon NAS 2002).

Optimization of therapy for severe aplastic anemia based on clinical, biologic, and treatment response parameters: conclusions of an international working group on severe aplastic anemia convened by the Blood and Marrow Transplant Clinical Trials Network, March 2010

Although recent advances in therapy offer the promise for improving survival in patients with severe aplastic anemia (SAA), the small size of the patient population, lack of a mechanism in North America for longitudinal follow-up of patients, and inadequate cooperation among hematologists, scientists, and transplant physicians remain obstacles to conducting large studies that would advance the field. To address this issue, the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) convened a group of international experts in March 2010 to define the most important questions in the basic science, immunosuppressive therapy (IST), and bone marrow transplantation (BMT) of SAA and propose initiatives to facilitate clinical and biologic research. Key conclusions of the working group were: (1) new patients should obtain accurate, expert diagnosis and early identification of biologic risk; (2) a population-based SAA outcomes registry should be established in North America to collect data on patients longitudinally from diagnosis through and after treatment; (3) a repository of biologic samples linked to the clinical data in the outcomes registry should be developed; (4) innovative approaches to unrelated donor BMT that decrease graft-versus-host disease are needed; and (5) alternative donor transplantation approaches for patients lacking HLA-matched unrelated donors must be improved. A partnership of BMT, IST, and basic science researchers will develop initiatives and partner with advocacy and funding organizations to address these challenges. Collaboration with similar study groups in Europe and Asia will be pursued.

Changes in amino acids and lipids during embryogenesis of European lobster, Homarus gammarus (Crustacea: Decapoda)

We studied the amino acid and lipid dynamics during embryogenesis of Homarus gammarus. Major essential amino acids (EAA) in the last stage of embryonic development were arginine, lysine and leucine; major nonessential amino acids (NEAA) were glutamic acid, aspartic acid, valine and glycine. The highest percent of utilization occurred in respect to EAA (27.8%), mainly due to a significant decrease (p<0.05) of methionine (38.3%) and threonine (36.0%). NEAA also decreased significantly (p<0.05, 11.4%), namely serine (38.1%), tyrosine (26.4%) and glutamic acid (25.7%). In contrast, the free amino acid content increased significantly (p<0.05) during embryonic development, especially the free nonessential amino acids (FNEAA). In the last stage, the most abundant FNEAA were glycine, proline, alanine and taurine, and the major free essential amino acids (FEAA) were arginine, lysine and leucine. Lipid content decreased significantly (p<0.05) during embryonic development. A substantial decrease in all neutral lipid classes was observed (>80% of utilization). Major fatty acids were 16:0, 18:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Unsaturated (UFA) and saturated fatty acids (SFA) were used up at similar rates (76.5% and 76.3%, respectively). Within UFA, monounsaturates (MUFA) were consumed more than polyunsaturates (PUFA) (82.9% and 67.5%, respectively).