Quantification of T-cell and B-cell replication history in aging, immunodeficiency, and newborn screening

Quantification of T-cell receptor excision circles (TRECs) has impacted on human T-cell research, but interpretations on T-cell replication have been limited due to the lack of a genomic coding joint. We here overcome this limitation with multiplex TRG rearrangement quantification (detecting ∼0.98 alleles per TCRαβ+ T cell) and the HSB-2 cell line with a retrovirally introduced TREC construct. We uncovered 10 cell divisions in effector memory T-cell subsets. Furthermore, we show that TREC dilution with age in healthy adults results mainly from increased T cell replication history. This proliferation was significantly increased in patients with predominantly antibody deficiency. Finally, Guthrie cards of neonates with Down syndrome have fewer T and B cells than controls, with similar T-cell and slightly higher B-cell replication. Thus, combined analysis of TRG coding joints and TREC signal joints can be utilized to quantify in vivo T-cell replication, and has direct applications for research into aging, immunodeficiency, and newborn screening

Molecular HLA typing for bone marrow transplantation in Malaysia

In recent years, there have been various advancements in HLA typing for transplantation. Molecular methods such as restriction fragment length polymorphism (RFLP), PCR SSO, and PCR SSP have been developed to supplement and even replace conventional serological. typing methods for transplantation especially bone marrow transplantation. HLA typing at the molecular level permits a resolution that is higher without the problems associated with serological cross reactivity. Furthermore, new alleles are constantly being elucidated. We have modified and utilized a comprehensive molecular typing method known as Phototyping. It is based on sequence specific primer amplification (PCR SSP) and was initially developed at the Oxford Transplant Centre in 1995. We phototyped 30 individuals involved in the University Malaya Medical Centre (UMMC) Bone Marrow Transplantation progamme for HLA A, B, DRB1, DRB3, DRB4, DRB5 and DQBI at the medical faculty and compared the results blind with HLA typing (DNA typing) done at the CMII (Centre for Molecular Immunology and Instrumentation, University of Western Australia) on the same individuals. Upon comparison of results, we report that the overall concordance is excellent for all matched loci except for some minor discrepancies at HLA B loci. Although our method requires a high degree technical of expertise, it is reliable and reproducible. This study demonstrates the feasibility of molecular HLA typing in the Malaysian transplantation scenario

Chemo-mechanical model for degradation of oil paintings by amorphous and crystalline metal soaps

Metal soap formation is recognised as a critical degradation mechanism in historical oil paintings, which threatens the preservation of museum collections worldwide. Metal soaps form via a complex sequence of chemical reactions between metal ions released by the pigments and saturated fatty acids originating from the drying oil. The latest advances in chemistry research suggest that metal ions and saturated fatty acids may initially react by means of a reversible reaction, which leads to the formation of metal soaps in an amorphous state. Metal soaps may subsequently crystallise via an irreversible reaction into large aggregates that deform the paint layers, potentially triggering delamination, cracking, and ultimately flaking of the paint. This paper proposes a chemo-mechanical model to predict metal soap formation and the consequent mechanical damage in historical oil paintings. The chemical process is described in terms of a set of diffusion–reaction equations, which account for both the reversible reaction between free saturated fatty acids and metal ions forming amorphous metal soap, and the subsequent irreversible reaction to crystalline metal soap. The chemical model is two-way coupled with a mechanical model that effectively describes the cracking processes caused by metal soap formation and growth. The coupling is generated from the mechanical model by accounting for the development of a chemically-induced growth strain in the crystalline metal soap. In addition, the presence of cracks locally hampers the diffusion of chemical species, which is taken into account in the chemical model through a dependency of the diffusion parameter at the crack faces on the amount of mechanical damage generated. The spatial development of the crystalline metal soap phase is simulated by using a tailor-made scanning algorithm that identifies the reaction zone in which metal soap formation takes place. The proposed model is calibrated on experimental data presented in the literature. The model is subsequently applied to analyse two numerical examples that are representative of typical metal soap-related degradation processes observed in historical oil paintings, revealing that the growth process of crystalline metal soap, the deformation of the paint surface, and the consequent cracking and delamination patterns are predicted in a realistic fashion

Osteogenicity of titanium implants coated with calcium phosphate or collagen type-I in osteoporotic rats

Item does not contain fulltextThis study hypothesized that modification of titanium implant surface, e.g. by the deposition of inorganic/organic coatings, can significantly improve the implant-bone response compared in osteoporotic vs. healthy conditions. After osteoporosis was induced in 15 female Wistar rats by ovariectomy (OVX) and confirmed by in vivo micro-CT analysis, implants coated with calcium phosphate (CaP) or collagen type-I and non-coated implants were placed into bilateral femoral condyles. Another 15 sham-operated rats served as controls. Twelve weeks after implantation, micro-CT bone volume (%BV) and histomorphometrical bone area (%BA) were lower around control implants in osteoporotic rats (BV = 60.4%, BA = 43.8%) compared to sham-operated rats (BV = 74.0%, BA = 62.0%). Interestingly, CaP and collagen type-I surface coatings enhanced bone-to-implant contact (%BIC) compared to non-coated implants in osteoporosis (51.9%, 58.2%) as well as in sham-operated (69.7%, 64.4%) groups. The study confirmed that an osteoporotic condition has a significant effect on the amount of bone present in close vicinity to implants. Evidently, the use of osteogenic surface coatings has a favorable effect on the bone implant interface in both osteoporotic and sham-operated conditions

Kinesiological Factors in Vertical Jump Performance: Differences WITHIN Individuals

The purpose of this study was to examine the changes in both the coordination patterns of segmental actions and the dynamics of vertical jumping that accompany changes in vertical jump performance (VJP) occurring from trial to trial in single subjects. Ground reaction forces and video data were analyzed for 50 maximal vertical jumps for 8 subjects. It was possible to predict VJP from whole-body or even segmental kinematics and kinetics in spite of the small jump performance variability. Best whole-body models included peak and average mechanical power, propulsion time, and peak negative impulse. Best segmental models included coordination variables and a few joint torques and powers. Contrary to expectations, VJP was lower for trials with a proximal-to-distal sequence of joint reversals.University of Michigan/[Rackham Dissertation Grant]/UM/Estados UnidosUniversity of Michigan/[Rackham Predoctoral Fellowship]/UM/Estados UnidosUniversidad de Costa Rica/[245-95-276]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Educación::Escuela de Educación Físic