Time of day effect on balance performance,functional capacities and risk of fall in women with rheumatoid arthritis

ABSTRACT

Objective: This study explored the time of day effect of balance performance, functional capacities and risk of fall in three different times in patients with rheumatoid arthritis (RA) and the association between these variations and those of RA symptoms.

Methods: A “discontinual” protocol, composed of three test sessions, carried out at 6 am, 2 pm and 10 pm was set up, in order to investigate the time of day effect of balance performance, functional capacities, risk of fall, stiffness, range of motion, swollen and painful joints in women with RA.

Results: Time Up and Go Test (TUGT), Functional Reach Test (FRT) and tinetti test scores were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. Stiffness, range of motion, swollen and painful joints values were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. A significant difference was observed on the stiffness, range of motion and swollen joints values between 6 am and 10 pm that were higher at 6 am (p < .05).

Using Pearson’s coefficient, correlations were found between RA symptom values; and TUGT, FRT and Tinetti test scores.

Conclusion: Results showed a time of day effect of balance performance, functional capacities and risk of falls in women with RA. This variation indicates an alteration of performance at 6 am and 10 pm. Fluctuations of stiffness, limited range of motion, swollen and painful joints noted are concomitant to those of balance performance, functional capacities, and risk of fall.

Abbreviations: RA: rheumatoid arthritis; H&O questionnaire: Horne and Ostberg questionnaire; PSQI: Pittsburgh sleep quality index; HAQ: health assessment questionnaire; SF-36: the short form-36; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; TUGT: Time Up and Go Test; FRT: Functional Reach Test     

Constructing Confidence Intervals for Qtl Location

We describe a method for constructing the confidence interval of the QTL location parameter. This method is developed in the local asymptotic framework, leading to a linear model at each position of the putative QTL. The idea is to construct a likelihood ratio test, using statistics whose asymptotic distribution does not depend on the nuisance parameters and in particular on the effect of the QTL. We show theoretical properties of the confidence interval built with this test, and compare it with the classical confidence interval using simulations. We show in particular, that our confidence interval has the correct probability of containing the true map location of the QTL, for almost all QTLs, whereas the classical confidence interval can be very biased for QTLs having small effect.     

The murine AIDS virus Gag precursor protein binds to the SH3 domain of c-Abl.

The Pr60gag protein of the murine AIDS (MAIDS) defective virus promotes the proliferation of the infected target B cells and is responsible for inducing a severe immunodeficiency disease. Using the yeast two-hybrid system, we identified the SH3 domain of c-Abl as interacting with the proline-rich p12 domain of Pr60gag. The two proteins were shown to associate in vitro and in vivo in MAIDS virus-infected B cells. Overexpression of Pr60(gag) in these cells led to a detectable increase of the levels of c-Abl protein and to its translocation at the membrane. These results suggest that this viral protein serves as a docking site for signaling molecules and that c-Abl may be involved in the proliferation of infected B cells.     

Murine H-2Dd-reactive monoclonal antibodies recognize shared antigenic determinant(s) on human HLA-B7 or HLA-B27 molecules or both

We have evaluated the serological relationships between the murine H-2Dd and human HLA molecules using four H-2Dd-reactive monoclonal antibodies (mAbs) produced in the A.BY (KbIbDb) anti-A.TL (KsIkDd) combination. In the mouse, these reagents exhibited three distinct reactivity patterns: Dd, Ks, and H-2u (mAb 81.L); Dd, H-2p, and H-2u (mAb 81.R); and Dd, Kd, H-2p, H-2u, and H-2v (mAbs 97.G and 97.H). Sequential immunoprecipitation and cross-competitive mAb binding experiments revealed that these mAbs recognized determinants in two spatially distinct polymorphic domains on the H-2Dd molecule of B10.A(5R) cells (defined by mAbs 81.L and 81.R, 97.H, and 97.G, respectively). MAbs 81.R, 97.G, and 97.H, but not 81.L, also defined an HLA-linked polymorphism in the human, the main characteristics of which can be summarized as follows: (i) on B lymphoblastoid cell lines, mAbs 81.R and 97.H bound to cells expressing the HLA-B7, HL-B27 or Bw40 cross-reacting specificities, (ii) on peripheral blood lymphocyte (PBL) panel mAb 81.R exerted C dependent cytotoxicity to 118 of 400 cells tested, including almost all HLA-B7 or HLA-B27 cells or both (r: 0.952), (iii) the expression of the 81.R cross-reacting determinant segregated in an informative family with the parental haplotype carrying the HLA-B7 allele, and (iv) mAbs 81.R, 97.G, and 97.H recognized topologically related determinants on the same class I molecule(s) of the human B lymphoblastoid cells JY (HLA-A2,2, -B7,7). These data support the view that some, but not all H-2Dd allotopes have been conserved throughout evolution and are associated in the human with the HLA-B7, -B27 cross-reacting specificities.     

Storage and reproductive strategy of the carpet-shell clam,Ruditapes decussatus in the Gulf of Gabès (Tunisia)

In this study, the variations of glycogen concentrations in Ruditapes decussatus from Sfax coasts (Tunisia) were described in relation to the reproductive cycle. Separate analyses were made of gonad, adductor muscle and ‘remainder’. The timing of gametogenic development and spawning was evaluated using qualitative histology associated with image analysis including (1) the estimation of the gonadal occupation index (GOI), (2) surface area occupied by reserve tissues and (3) variation in oocyte diameter. The reproductive cycle of R. decussatus exhibited partial asynchronization between sexes, the major difference being observed in the duration of the spawning period. Contrary to previous studies, we observed continuous partial spawning (e.g. 50% of ripe oocytes still subsisted at the partial spawning stage). During the gametogenic cycle, GOI varied significantly in males and in females. Most oocytes were ripe and ready to spawn when their diameter reached or exceeded 45?µm. The expansion of gonad was inversely proportional to the development of the foot tissue. Glycogen concentration showed significant temporal variations between tissues, indicating the clear differentiation in energy storage between the clam organs.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Pistacia lentiscus fruit oil reduces oxidative stress in human skin explants caused by hydrogen peroxide

We investigated the efficacy of Pistacia lentiscus fruit oil (PLFO) for protecting human skin from damage due to oxidative stress. PLFO contains natural antioxidants including polyphenols, sterols and tocopherols. We compared the antioxidant potential of PLFO with extra virgin olive oil (EVOO). Explants of healthy adult human skin were grown in culture with either PLFO or EVOO before adding hydrogen peroxide (H₂O₂). We also used cultured skin explants to investigate the effects of PLFO on lipid oxidation and depletion of endogenous antioxidant defense enzymes including glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) one day after 2 h exposure to H₂O₂. We found that PLFO scavenged radicals and protected skin against oxidative injury. PLFO exhibited greater antioxidant and free radical scavenging activity than EVOO. Skin explants treated with PLFO inhibited H₂O₂ induced MDA formation by inhibition of lipid oxidation. In addition, the oil inhibited H₂O₂ induced depletion of antioxidant defense enzymes including GPx, SOD and CAT. We found that treatment with PLFO repaired skin damage owing to its antioxidant properties.     

Autophagy and senescence: A new insight in selected human diseases

Senescence and autophagy play important roles in homeostasis. Cellular senescence and autophagy commonly cause several degenerative processes, including oxidative stress, DNA damage, telomere shortening, and oncogenic stress; hence, both events are known to be interrelated. Autophagy is well known for its disruptive effect on human diseases, and it is currently proposed to have a direct effect on triggering senescence and quiescence. However, it is yet to be proven whether autophagy has a positive or negative impact on senescence. It is known that elevated levels of autophagy induce cell death, whereas inadequate autophagy can trigger cellular senescence. Both have important roles in human diseases such as aging, renal degeneration, neurodegenerative disorders, and cancer. Therefore, this review aims to highlight the relevance of senescence and autophagy in selected human ailments through a summary of recent findings on the connection and effects of autophagy and senescence in these diseases.     

Acute effect of hemodialysis on serum levels of the proinflammatory cytokines

Chronic inflammation is a common feature of end-stage renal disease, which carries a heightened risk of atherosclerosis and other co-morbid conditions. Dialysis treatment per se can bring additional risk factors for inflammation, such as increased risk of local graft and fistula infections, impure dialysate or bio-incompatible membranes. Our study was designed to determine whether a hemodialysis session leads to an acute substantial alteration in the plasma levels of the proinflammatory cytokines interleukin (IL)-6, IL-1beta and tumor necrosis factor (TNF)-alpha, the T-lymphocyte activation factor soluble IL-2 receptor (sIL-2R), and an inflammation mediator and chemotactic granulocyte factor, IL-8, in end-stage renal disease patients receiving chronic intermittent HD. In this study, 21 (12 male/nine female) patients undergoing chronic hemodialysis were enrolled. The acute effect of a hemodialysis session on serum cytokine concentrations was assessed by comparison of pre-hemodialysis and post-hemodialysis determinations. Serum IL-1beta, sIL-2R, IL-6, IL-8 and TNF-alpha levels were determined with chemiluminescence enzyme immunometric assays. A significant difference was not observed for IL-1beta, IL-6, TNF-alpha, and sIL-2R concentrations in pre-hemodialysis and post-hemodialysis specimens (p>0.05). Serum median (25th-75th percentiles) IL-8 concentration was 69.4 (34.9-110.3) pg/ml before hemodialysis, and decreased to 31.5 (18.0-78.8) pg/ml following hemodialysis (p: 0.006). Clearance of IL-8 increased by 0.47+/-0.08 pg/ml for each unit increase in pre-dialysis IL-8 (p<0.001) and decreased by 5.63+/-2.59 pg/ml for each unit increase in pre-dialysis urea mmol/l (p<0.05). In conclusion, the results of our study demonstrate that a hemodialysis session markedly decreases IL-8 concentration, which is significantly affected by pre-dialysis concentrations, indicating that removal of IL-8 is a concentration gradient-dependent action, but does not change the serum levels of IL-1beta, sIL-2R, IL-6, and TNF-alpha, underlining importance of the structural characteristics of the molecules.     

Influence of Affective Stimuli on Leg Power Output and Associated Neuromuscular Parameters during Repeated High Intensity Cycling Exercises

The aim of this study was to examine the impact of emotional eliciting pictures on neuromuscular performance during repetitive supramaximal cycling exercises (RSE). In a randomized order, twelve male participants were asked to perform five 6-s cycle sprints (interspaced by 24 s of recovery) on a cycle ergometer in front of neutral, pleasant or unpleasant pictures. During each RSE, mean power output (MPO) and electromyographic activity [root mean square (RMS) and median frequency (MF)] of the vastus lateralis and vastus medialis muscles were analyzed. Neuromuscular efficiency (NME) was calculated as the ratio of MPO to RMS. Higher RMS (232.17 ± 1.17 vs. 201.90 ± 0.47 μV) and MF (68.56 ± 1.78 vs. 64.18 ± 2.17 Hz) were obtained in pleasant compared to unpleasant conditions (p < 0.05). This emotional effect persisted from the first to the last sprint. Higher MPO was obtained in pleasant than in unpleasant conditions (690.65 ± 38.23 vs. 656.73 ± 35.95 W, p < 0.05). However, this emotional effect on MPO was observed only for the two first sprints. NME decreased from the third sprint (p < 0.05), which indicated the occurrence of peripheral fatigue after the two first sprints. These results suggested that, compared with unpleasant pictures, pleasant ones increased the neuromuscular performance during RSE. Moreover, the disappearance of the beneficial effect of pleasant emotion on mechanical output from the third sprint appears to be due to peripheral fatigue.