Numerical Modelling Of The V-J Combinations Of The T Cell Receptor TRA/TRD Locus

T-Cell antigen Receptor (TR) repertoire is generated through rearrangements of V and J genes encoding α and β chains. The quantification and frequency for every V-J combination during ontogeny and development of the immune system remain to be precisely established. We have addressed this issue by building a model able to account for Vα-Jα gene rearrangements during thymus development of mice. So we developed a numerical model on the whole TRA/TRD locus, based on experimental data, to estimate how Vα and Jα genes become accessible to rearrangements. The progressive opening of the locus to V-J gene recombinations is modeled through windows of accessibility of different sizes and with different speeds of progression. Furthermore, the possibility of successive secondary V-J rearrangements was included in the modelling. The model points out some unbalanced V-J associations resulting from a preferential access to gene rearrangements and from a non-uniform partition of the accessibility of the J genes, depending on their location in the locus. The model shows that 3 to 4 successive rearrangements are sufficient to explain the use of all the V and J genes of the locus. Finally, the model provides information on both the kinetics of rearrangements and frequencies of each V-J associations. The model accounts for the essential features of the observed rearrangements on the TRA/TRD locus and may provide a reference for the repertoire of the V-J combinatorial diversity

Old World Arenaviruses Enter the Host Cell via the Multivesicular Body and Depend on the Endosomal Sorting Complex Required for Transport

The highly pathogenic Old World arenavirus Lassa virus (LASV) and the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) use α-dystroglycan as a cellular receptor and enter the host cell by an unusual endocytotic pathway independent of clathrin, caveolin, dynamin, and actin. Upon internalization, the viruses are delivered to acidified endosomes in a Rab5-independent manner bypassing classical routes of incoming vesicular trafficking. Here we sought to identify cellular factors involved in the unusual and largely unknown entry pathway of LASV and LCMV. Cell entry of LASV and LCMV required microtubular transport to late endosomes, consistent with the low fusion pH of the viral envelope glycoproteins. Productive infection with recombinant LCMV expressing LASV envelope glycoprotein (rLCMV-LASVGP) and LCMV depended on phosphatidyl inositol 3-kinase (PI3K) as well as lysobisphosphatidic acid (LBPA), an unusual phospholipid that is involved in the formation of intraluminal vesicles (ILV) of the multivesicular body (MVB) of the late endosome. We provide evidence for a role of the endosomal sorting complex required for transport (ESCRT) in LASV and LCMV cell entry, in particular the ESCRT components Hrs, Tsg101, Vps22, and Vps24, as well as the ESCRT-associated ATPase Vps4 involved in fission of ILV. Productive infection with rLCMV-LASVGP and LCMV also critically depended on the ESCRT-associated protein Alix, which is implicated in membrane dynamics of the MVB/late endosomes. Our study identifies crucial cellular factors implicated in Old World arenavirus cell entry and indicates that LASV and LCMV invade the host cell passing via the MVB/late endosome. Our data further suggest that the virus-receptor complexes undergo sorting into ILV of the MVB mediated by the ESCRT, possibly using a pathway that may be linked to the cellular trafficking and degradation of the cellular receptor

Leaf anatomy of genotypes of banana plant grown under coloured shade nets

This study aimed to evaluate  the effect of spectral light quality on different anatomical features of banana tree plantlets grown under coloured shade nets. Banana plants of five genotypes (Maçã, Thap Maeo, Caipira, BRS Platina and Princesa), obtained from micropropagation, were grown under white, blue, red and black nets, with shade of 50%, in a completely randomized design. After 90 days of acclimatization under nets, the leaves were collected and analyzed anatomically following basic protocol of plant microtechnique. Cultivation under white net provided greater thickness of epidermis cells, hypodermis on the adaxial face and palisade parenchyma; and greater stomatal density on the adaxial face; both the red and white nets, however, increased stomatal density on the abaxial face. The use of white net, during the acclimatization phase, is recommended  for cultivation of banana plantlets obtained of micropropagation.Keywords: Musa sp., acclimatization, spectral quality, anatomical plasticityAfrican Journal of Biotechnology, Vol 13(23) 2359-236

Preoperative assessment of peritoneal carcinomatosis in patients undergoing hyperthermic intraperitoneal chemotherapy following cytoreductive surgery.

The present study evaluates the accuracy of computed tomographic (CT) scan and positron emission tomography with F-18-fluorodeoxyglucose (FDG-PET)/CT for the quantification of peritoneal carcinomatosis (PC) in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Data were retrospectively collected for 58 patients, who were considered for CRS and HIPEC. The predictability, sensitivity, specificity and accuracy values of FDG-PET/CT and CT were tested. Preoperative CT and FDG-PET/CT failed to detect PC in 9% and 17% of cases, respectively, with a sensitivity of 91% and 82%, a specificity of 33% and 67%, an area under the curve (AUC) of 62% and 74% and a negative likelihood ratio of 027 (CI.95 0.07-1.09) and 027 (CI.95 0.11-0.62), respectively (p=0.469). Both techniques showed a high prevalence of PC extent underestimation (CT 47% and FDG-PET/CT 43% of cases). Small bowel involvement and optimal CRS had a prevalence of 60% and 76%, respectively, and both the CT and FDG-PET/CT imaging techniques were inaccurate at predicting them (AUC 53% and 52% for small bowel involvement, and 63% and 58% for optimal CRS, respectively). In conclusion both CT and FDG-PET/CT had low preoperative staging reliability for PC, and this can strongly influence the ability to implement the correct treatment strategy for patients with PC

Distribution of human recombinant interferon-alpha 2 in rat plasma, liver, and experimental liver metastases.

It has been ascertained that one of several possible reasons for negligible interferon activity in solid tumors, namely, hepatic metastases induced in rats after intraportal injection of Walker carcinoma 256 cells, is the significantly lower levels of interferon in the interstitial fluid of metastases in comparison to normal liver and plasma