Restricted immunoglobulin VH region repertoire in chronic lymphocytic leukemia patients with autoimmune hemolytic anemia

Between 10% and 25% of chronic lymphocytic leukemia (CLL) patients have episodes of autoimmune hemolytic anemia (AIHA) during the course of their disease. The anti-erythrocyte autoantibodies in most cases are polyclonal and express a different heavy chain isotype than the malignant clone, indicating that they are secreted by normal autoreactive B lymphocytes. To further investigate the pathogenesis of the AIHA in CLL, we analyzed the lg heavy (H) chain variable region genes expressed by leukemic cells from CLL patients with and without AIHA. Two VH genes were preferentially expressed by the leukemic cells in the CLL cases with AIHA and were present in 9 of the 12 investigated cases. The 51p1/DP-10 gene was expressed in 5 of these cases and was absent in the control group of 12 consecutive CLL cases without AIHA, whereas the DP-50 gene was present in 4 CLL-AIHA cases and only once in the control CLL group. A strikingly similar H-chain CDR3 region that contained a single reading frame of the DXP4 DH gene segment, and N- encoded proline at the DH/JH boundary, and a tyrosine-rich region encoded by the JH6 gene segment was observed in four CLL-AIHA cases. The preferential expression of two VH gene segments and a particular CDR3 region by the leukemic cells of patients with AIHA suggests that the antibodies produced by the CLL cells are directly involved in the pathogenesis of the hemolytic anemia.     

非转流小型猪原位肝移植模型的建立及评价

目的:建立标准化程度高、重复性和稳定性好的小型猪原位肝移植模型。方法:实验于2004-06/2006-02在南方医科大学南方医院动物研究所完成。选用健康中国版纳小型猪36只,按随机数字表法分为供、受体各18只,施行非转流小型猪原位肝移植手术18例。在非体外静脉转流的条件下行同种异体原位肝移植术,严格控制动物无肝期时间,应用套管法吻合胆总管,另外加强围手术期的处理,使无肝期的血压维持在满意水平。监测动物无肝期时间、手术时间、失血量、输血量及动物存活期;术中监测动物的血液动力学及动脉血气分析、生化指标变化;猪死后当天行尸体解剖明确死亡原因。结果:成功建立非转流小型猪原位肝移植模型18只,均纳入结果分析,无脱失。①实验动物无术中死亡,术后当天死亡1只,死亡原因为急性肺水肿;术后第2天死亡1只,死亡原因为胆总管吻合口胆瘘。术后7d存活率为88.9%。②手术时间、无肝期时间、术中失血量及输血量分别为(179.61±14.27)min,(27.28±3.43)min,(422.22±66.91)mL及(444.44±51.13)mL。③与无肝前期相比,实验动物无肝期平均动脉压、中心静脉压、pH值及碱剩余明显下降(P<0.05￣0.01),心率及血清钾水平显著升高(P<0.01);手术结束时平均动脉压及中心静脉压恢复,经药物调整后血清钾水平下降,pH值逐渐恢复。结论:非转流条件下的小型猪原位肝移植模型是肝移植实验的理想动物模型。     

Bone Density and Cross-sectional Geometry of the Proximal Femur Are Bilaterally Elevated in Elite Cricket Fast Bowlers

The skeleton of a cricket fast bowler is exposed to a unique combination of gravitational and torsional loading in the form of substantial ground reaction forces delivered through the front landing foot, and anterior-posterior shear forces mediated by regional muscle contractions across the lumbo-pelvic region. The objectives of this study were to compare the hip structural characteristics of elite fast bowlers with recreationally active age-matched controls, and to examine unilateral bone properties in fast bowlers. Dual-energy X-ray absorptiometry of the proximal femur was performed in 26 elite male fast bowlers and 26 normally active controls. Hip structural analysis (GE Lunar; enCORE version 15.0) determined areal bone mineral density (BMD) of the proximal femur, and cross-sectional area, section modulus (Z), cross-sectional moment of inertia, and femoral strength index at the narrow region of the femoral neck. Mean femoral neck and trochanter BMD were greater in fast bowlers than in controls (p?<0.001). All bone geometry properties, except for cross-sectional moment of inertia, were superior in fast bowlers (p?<0.05) following adjustment for height and lean mass. There were no asymmetries in BMD or bone geometry when considering leg dominance of the fast bowlers (p?>?0.05). Elite fast bowlers have superior bone characteristics of the proximal femur, with results inferring enhanced resistance to axial compression (cross-sectional area), and bending (Z) forces, and enhanced strength to withstand a fall impact as indicated by their higher femoral strength index. No asymmetries in hip bone properties were identified, suggesting that both torsional and gravitational loading offer significant osteogenic potential.     

Inhibition of Potentially Pathogenic Yeastlike Fungi by Clotrimazole in Combination with 5-Fluorocytosine or Amphotericin B

Clotrimazole (CTM) has a doubtful future with respect to use in treatment of the systemic mycoses. To assess the potential of CTM in combined drug regimens, antifungal effects of CTM together with 5-fluorocytosine (5-FC) or amphotericin B (AMB) were tested in a synthetic liquid medium against Candida albicans, Candida tropicalis, and Torulopsis glabrata. Viable counts were monitored over a 48-h incubation period. Weak inhibitory concentrations of CTM were tested in combination with levels of 5-FC or AMB that alone produced transient antifungal effects followed by rapid recovery of proliferative capacity. Results were similar for each of the organisms studied. Between 24 and 48 h, when cultures containing 5-FC or AMB alone were in the recovery phase, CTM plus 5-FC and CTM plus AMB continued to markedly suppress cell multiplication. It would appear that weak inhibitory concentrations of CTM can act together with 5-FC or AMB to produce antifungal effects greater than that obtained with either of the latter two drugs alone.     

Increased Slc34a2 expression and paracellular phosphate permeability contribute to high intestinal phosphate absorption in young mice

Aim

Phosphorus is a critical constituent of bone as a component of hydroxyapatite. Bone mineral content accrues rapidly early in life necessitating a positive phosphorus balance, which could be established by a combination of increased renal reabsorption and intestinal absorption. Intestinal absorption can occur via a transcellular pathway mediated by the apical sodium-phosphate cotransporter, Slc34a2/NaPiIIb or via the paracellular pathway. We sought to determine how young mammals increase dietary phosphorus absorption from the small intestine to establish a positive phosphorus balance, a prerequisite for rapid bone growth.

Methods

The developmental expression profile of genes mediating phosphate absorption from the small intestine was determined in mice by qPCR and immunohistochemistry. Additionally, Ussing chamber studies were performed on small bowel of young (p7–p14) and older (8- to 17-week-old) mice to examine developmental changes in paracellular Pi permeability and transcellular Pi transport.

Results

Blood and urinary Pi levels were higher in young mice. Intestinal paracellular phosphate permeability of young mice was significantly increased relative to older mice across all intestinal segments. NaPiIIb expression was markedly increased in juvenile mice, in comparison to adult animals. Consistent with this, young mice had increased transcellular phosphate flux across the jejunum and ileum relative to older animals. Moreover, transcellular phosphate transport was attenuated by the NaPiIIb inhibitor NTX1942 in the jejunum and ileum of young mice.

Conclusion

Our results are consistent with young mice increasing phosphate absorption via increasing paracellular permeability and the NaPiIIb-mediated transcellular pathway.