Modern femoral component design in total knee arthroplasty shows a lower patellar contact force during knee flexion compared with its predecessor

BackgroundThe relationship between the femoral component design in total knee arthroplasty (TKA) and the patellofemoral contact force, as well as the soft tissue balance, has not been well reported thus far.MethodsTwenty-eight mobile-bearing posterior-stabilized (PS) TKAs using the traditional model (PFC Sigma) and 27 mobile-bearing PS TKAs using the latest model (Attune) were included. Surgeries were performed using the measured resection technique assisted with the computed tomography (CT)-based free-hand navigation system. After all the trial components were placed, patellar contact forces on the medial and lateral sides were measured using two uniaxial ultrathin force transducers with the knee at 0°, 10°, 30°, 60°, 90°, 120°, and 135° of flexion. The joint component gap and the varus ligament balance of the femorotibial joint were also measured. The non-paired Student’s t-test was conducted to compare the values of the two groups.ResultsThe medial patellar contact force was significantly lower for Attune group than for PFC Sigma group at 120° of knee flexion (P = 0.0058). The lateral patellar contact force was also significantly lower for Attune group than PFC Sigma group at 120° and 135° of knee flexion (P = 0.0068 and P = 0.036). The joint component gap, as well as the varus ligament balance, showed no statistically significant difference between the two groups.ConclusionsReduced thickness and width of the anterior flange of the femoral component in the Attune may play a role in low patellar contact force.     

GABA(B) receptor GTP-binding is decreased in the prefrontal cortex but not the hippocampus of aged rats

Gamma aminobutyric acid (GABA)(B) receptors (GABA(B)Rs) have been linked to a wide range of physiological and cognitive processes and are of interest for treating a number of neurodegenerative and psychiatric disorders. As many of these diseases are associated with advanced age, it is important to understand how the normal aging process impacts GABA(B)R expression and signaling. Thus, we investigated GABA(B)R expression and function in the prefrontal cortex (PFC) and hippocampus of young and aged rats characterized in a spatial learning task. Baclofen-stimulated GTP-binding and GABA(B)R1 and GABA(B)R2 proteins were reduced in the prefrontal cortex of aged rats but these reductions were not associated with spatial learning abilities. In contrast, hippocampal GTP-binding was comparable between young and aged rats but reduced hippocampal GABA(B)R1 expression was observed in aged rats with spatial learning impairment. These data demonstrate marked regional differences in GABA(B)R complexes in the adult and aged brain and could have implications for both understanding the role of GABAergic processes in normal brain function and the development of putative interventions that target this system.     

Properdin deficiency associated with recurrent otitis media and pneumonia, and identification of male carrier with Klinefelter syndrome

Properdin is an initiator and stabilizer of the alternative complement activation pathway (AP). Deficiency of properdin is a rare X-linked condition characterized by increased susceptibility to infection with Neisseria meningitidis associated with a high mortality rate. We report properdin deficiency in a large Pakistani family. The index cases were found by screening for immunodeficiency due to a history of recurrent infections. This revealed absent AP activity, but normal classical and lectin pathway activity. Sequencing of the properdin gene (PFC) revealed a novel frameshift mutation. When all available relatives (n = 24) were screened for the mutation, four affected males, four female carriers and a male heterozygous carrier were identified. He was subsequently diagnosed with Klinefelter syndrome. A questionnaire revealed a striking association between properdin deficiency and recurrent otitis media (P = 0.0012), as well as recurrent pneumonia (P = 0.0017).This study is the first to show a significant association between properdin deficiency and recurrent infections.     

Corrosion Performance of Nano-TiO2-Modified Concrete under a Dry–Wet Sulfate Environment

This study compared the effects of the sulfate dry–wet cycle on the properties of ordinary concrete and nano-TiO₂-modified concrete, including the mass loss rate, ultrasonic wave velocity, compressive strength, and XRD characteristics. In addition, a series of compression simulations carried out using the PFC2D software are also presented for comparison. The results show the following: (1) with an increase in dry–wet cycles, the damage to the concrete gradually increased, and adding nano-TiO₂ into ordinary concrete can improve the material’s sulfate resistance; (2) after 50 sulfate dry–wet cycles, the mass loss rate of ordinary concrete was –3.744%, while that of nano-TiO₂-modified concrete was −1.363%; (3) the compressive strength of ordinary concrete was reduced from 41.53 to 25.12 MPa (a reduction of 39.51%), but the compressive strength of nano-TiO₂-modified concrete was reduced from 49.91 to 32.12 MPa (a reduction of 35.64%); (4) after a sulfate dry–wet cycle, the nano-TiO₂-modified concrete surface produced white crystalline products, considered to be ettringite based on the XRD analysis; (5) when considering the peak stress and strain of the concrete samples, the numerical results agreed well with the test results, indicating the reliability of the method.     

Micro-Mechanism of Uniaxial Compression Damage of Layered Cemented Backfill in Underground Mine

Layering of filling body is common in large-scale filling areas. In this paper, the cement–sand ratio of 1:8 is based on the configuration of 68%, 70%, 72% and 74%; four concentrations; and filling layers of one-, two-, three- and four-layered cemented filling samples. Combined with a uniaxial compression test and two-dimensional particle flow software (PFC2D), the mechanical properties and failure modes were explored. The results show that the concentration can strengthen the uniaxial compressive strength of the filling body while increasing the filling times weakens its power; therefore, the constitutive damage model was constructed. It was found that the initial layered damage existed in the layered filling, and the total damage showed an upward trend of first fast and then slow; the main failure modes of one-layer and two-layer backfills showed prominent shear failure characteristics, and the three-layer and four-layer fillings were closer to tensile failure. From the crack generation to the specimen failure, there is a mutual conversion between different energies.     

Nonsuppression of cortisol in depression and immune function

Eighteen depressive patients and twenty-five healthy control subjects were studied using a comprehensive immunological test system and the dexamethasone suppression test (DST) as well as some additional neuroendocrine parameters. In addition, immune functions of six of the patients were studied serially three times at 1-2 month's intervals. The OKT 4+/8+ ratio (OKT 4+ = helper/inducer phenotype; OKT 8+ = suppressor/cytotoxic phenotype) was slightly higher in those ten depressive patients showing suppression in the DST than in healthy controls, but there were no significant differences between the nonsuppressor and suppressor groups or between the nonsuppressor and suppressor groups or between nonsuppressors and control subjects. Lymphocyte transformation responses induced by phytohaemagglutinin (PHA) were similar in the nonsuppressors and suppressors, but lower in both groups than in control subjects. The number of Ig-secreting cells measured in the absence and presence of pokeweed mitogen (PWM) were similar in the nonsuppressor and suppressor groups. Four of the depressive patients tested repeatedly exhibited an abnormal response in the DST at the beginning of the study. During the follow-up period two of them recovered completely from depression as well as the patients with a normal suppression in the DST. The proportions of T and B lymphocytes and regulatory T lymphocyte subsets as well as the functions of T and B lymphocytes of the nonsuppressors and suppressors in the DST were within normal ranges before and after recovery from depression and comparable to healthy controls in repeated testing. The results indicate that in spite of the importance of cortisol in immunoregulation, the increased cortisol secretion and typical resistance to dexamethasone suppression in endogenously depressive patients is not profoundly and consistently reflected in immune functions. Neither does normalization of cortisol responses induce any major changes in immune status during a patient's recovery from depression. Previous work indicates that suppressed immunity may play an important role in the increased morbidity and mortality associated with bereavement. In the light of present findings we suggest that endogenous depression differs also in this respect from grief reactions.     

恶性疟原虫PFC0460w基因片段的克隆与生物信息学分析

用逆转录PCR方法从恶性疟原虫3D7株红内期RNA扩增PFCO460w基因片段,克隆于pGEM-T easy载体,转化大肠埃希菌DH5α,筛选阳性克隆,PCR鉴定、测序并作序列分析。结果显示,从恶性疟原虫3D7株中扩增到3种PFCO460w片段序列,分别为618、597和543 bp,其中618 bp的片段序列与PlasmoDB数据库中的已知序列完全一致（GenBank登录号为XM₀01351147）。597 bp和543 bp片段序列已登录GenBank数据库,登录号分别为JF799872和JF799873。618 bp片段编码205个氨基酸,经Robbeta服务器结构预测,其编码的蛋白质可能有5种三维结构。     

Identification of neurotransmitter receptor genes involved in alcohol self-administration in the rat prefrontal cortex, hippocampus and amygdala

About half of the risk to develop alcoholism is related to genetic background and it is well known that alcohol consumption is highly individualized. In this study, we investigated how individual alcohol consumption behaviour in Wistar rats correlated with mRNA expression of 20 genes in the prefrontal cortex, hippocampus and amygdala. We found that the long-term alcohol consumption of an individual could be estimated by the mean of its consumption on Day 2 and 3. This short exposure minimized changes in gene expression induced by alcohol itself. We found a positive correlation in the prefrontal cortex of GABA(A) alpha5 (r=0.96), GABA(B1) (r=0.96), AMPA GluR1 (r=0.93), 5-HT(3A) (r=0.93) and the alpha adrenoceptors (alpha(1A)r=1.00, alpha(1B)r=0.93, alpha(2A)r=0.93) with consumption. In the hippocampus, we found negative correlations with the NMDA NR2A subunit (r=-0.86), the alpha(1A) adrenoceptor (r=-0.89) and the glucocorticoid receptor (r=-0.86). Finally, in the amygdala there was a negative correlation to NMDA NR2A (r= -0.79) and a positive correlation with serotonin 5-HT(2C) (r=0.79). In conclusion, we have used qPCR to identify specific genes in the brain that correlated to alcohol self-administration of an individual animal. This study suggests that alcohol consumption in the early stages of acquisition depends on the genetic background of the individual and that the prefrontal cortex is particularly important in this behaviour.     

Suppression of primary antibody response by a single exposure to cadmium in mice

Suppression of primary antibody response to sheep red blood cells (SRBC) by a single intraperitoneal (i.p.) injection of cadmium into mice was investigated by the methods of in vitro plaque-forming cell (PFC) assay. BALB/c mice were given 1.8 mg cadmium/kg body weight, and 1, 2 or 7 days later, spleen cells from exposed and control mice were cultured with SRBC. PFC responses of all exposed groups were significantly suppressed compared to those of control groups. Addition of control adherent cells to spleen cells from exposed mice failed to recover control level. In the cell-reconstitution experiments, the activity of B-cell function from the exposed group was suppressed more by cadmium than that of T-cell function. These results suggest that the suppression of primary PFC response by cadmium exposure may be caused by the inactivation of B-cells.