Plasmapheresis Eliminates the Negative Impact of AAV Antibodies on Microdystrophin Gene Expression Following Vascular Delivery

Duchenne muscular dystrophy is a monogenic disease potentially treatable by gene replacement. Use of recombinant adeno-associated virus (AAV) will ultimately require a vascular approach to broadly transduce muscle cells. We tested the impact of preexisting AAV antibodies on microdystrophin expression following vascular delivery to nonhuman primates. Rhesus macaques were treated by isolated limb perfusion using a fluoroscopically guided catheter. In addition to serostatus stratification, the animals were placed into one of the three immune suppression groups: no immune suppression, prednisone, and triple immune suppression (prednisone, tacrolimus, and mycophenolate mofetil). The animals were analyzed for transgene expression at 3 or 6 months. Microdystrophin expression was visualized in AAV, rhesus serotype 74 sero-negative animals (mean: 48.0 ± 20.8%) that was attenuated in sero-positive animals (19.6 ± 18.7%). Immunosuppression did not affect transgene expression. Importantly, removal of AAV binding antibodies by plasmapheresis in AAV sero-positive animals resulted in high-level transduction (60.8 ± 18.0%), which is comparable with that of AAV sero-negative animals (53.7 ± 7.6%), whereas non-pheresed sero-positive animals demonstrated significantly lower transduction levels (10.1 ± 6.0%). These data support the hypothesis that removal of AAV binding antibodies by plasmapheresis permits successful and sustained gene transfer in the presence of preexisting immunity (natural infection) to AAV.     

Factors affecting the therapeutic response of enalapril in treatment of post transplant erythrocytosis

Summary: Enalapril was used for post transplant erythrocytosis (PTE) in 19 stable male hypertensive renal allograft recipients. Post transplant erythrocytosis was defined as haematocrit (Hct) >0.45 for 3 consecutive months. Dosage of enalapril was adjusted according to the blood pressure of individual patients and varied from 2.5 mg to 20 mg per day in divided doses. Patients'serum creatinine level, blood pressure and haematocrit were monitored. Therapeutic response was expressed as percentage drop in Hct (Δ%Hct). Factors affecting Δ%Hct was then determined. After 32 weeks of treatment, haematocrit fell from 0.495 ± 0.021 to 0.396 ± 0.053, which represented a 19.9% drop (paired Student's t-test, P > 0.001). With multiple regression analysis, reciprocal of plasma creatinine (RCr) prior to enalapril therapy (B = 3.40 ± 0.72, P > 0.0005), dose of enalapril adjusted with bodyweight (B = - 0.058 ± 0.020, P > 0.02, and pre-treatment haematocrit level (B = - 1.90 ± 0.71, P > 0.02) were found to be independent factors affecting Δ%Hct. We concluded that the dosage of enalapril, renal allograft function and severity of erythrocytosis were the major factors affecting the therapeutic response of PTE by enalapril treatment.     

Surgical hip dislocation for treatment of cam femoroacetabular impingement

Background:

Cam femoroacetabular impingement is caused by a misshapen femoral head with a reduced head neck offset, commonly in the anterolateral quadrant. Friction in flexion, adduction and internal rotation causes limitation of the hip movements and pain progressively leading to labral and chondral damage and osteoarthritis. Surgical hip dislocation described by Ganz permits full exposure of the hip without damaging its blood supply. An osteochondroplasty removes the bump at the femoral head neck junction to recreate the offset for impingement free movement.

Materials and Methods:

Sixteen patients underwent surgery with surgical hip dislocation for the treatment of cam femoroacetabular impingement by open osteochondroplasty over last 6 years. Eight patients suffered from sequelae of avascular necrosis (AVN). Three had a painful dysplastic hip. Two had sequelae of Perthes disease. Three had combined cam and pincer impingement caused by retroversion of acetabulum. All patients were operated by the trochanteric flip osteotomy with attachments of gluteus medius and vastus lateralis, dissection was between the piriformis and gluteus minimus preserving the external rotators. Z-shaped capsular incision and dislocation of the hip was done in external rotation. Three cases also had subtrochanteric osteotomy. Two cases of AVN also had an intraarticular femoral head reshaping osteotomy.

Results:

Goals of treatment were achieved in all patients. No AVN was detected after a 6 month followup. There were no trochanteric nonunions. Hip range of motion improved in all and Harris hip score improved significantly in 15 of 16 cases. Mean alpha angle reduced from 86.13° (range 66°–108°) to 46.35° (range 39°–58°).

Conclusion:

Cam femoroacetabular Impingement causing pain and limitation of hip movements was treated by open osteochondroplasty after surgical hip dislocation. This reduced pain, improved hip motion and gave good to excellent results in the short term.     

Mechanisms of glutamate and aspartate release in the ischemic rat cerebral cortex

Elevated levels of glutamate and aspartate have been implicated in the pathogenesis of neural injury and death induced by ischemia. The mechanism(s) whereby they escape into the extracellular environment have been a subject of controversy. This study evaluated the contribution of phospholipases and protein kinases to ischemia-evoked glutamate and aspartate release from the ischemic/reperfused rat cerebral cortex. Changes in the extracellular levels of these amino acids during four-vessel occlusion elicited global cerebral ischemia were examined using a cortical cup technique. Ischemia-evoked amino acid release was compared in control vs. drug treated animals, in which selective inhibitors of phospholipases and protein kinases were applied topically onto the cerebral cortex. The phospholipase inhibitors tested included 4-bromophenacyl bromide, a non-selective inhibitor; 7,7-dimethyleicosadienoic (DEDA), an inhibitor of secretory type phospholipase A₂ (PLA₂); AACOCF₃, an inhibitor of the Ca²⁺-dependent cytoplasmic form of PLA₂, HELSS, which inhibits a Ca²⁺-independent cytoplasmic PLA₂, and U73122, a selective inhibitor of phospholipase C (PLC). All five phospholipase inhibitors significantly attenuated glutamate and aspartate release into the extracellular milieu, indicating the possibility that several forms of the enzyme are likely to be involved. The protein kinase C (PKC) inhibitor, chelerythrine chloride, also reduced excitatory amino acid efflux, whereas the PKC activator phorbol 12-myristate 13-acetate (PMA) enhanced their release. The non-selective kinase inhibitor, staurosporine, and H-89, which selectively inhibits protein kinase A, did not reduce ischemia-evoked amino acid efflux. These results suggest that ischemia-evoked release of the excitatory transmitters amino acids is a result, in part, of the activation of phospholipases A₂ and C, with PKC involvement in the transduction process. Destabilization and deterioration of the plasma membrane, as a consequence of phospholipid hydrolysis, may allow these transmitter amino acids to diffuse down their concentration gradients into the extracellular fluid.     

电子束计算机体层成像用于诊断冠状动脉疾病

背景 :电子束计算机体层成像 (ＥＢＣＴ)是检查冠状动脉钙化的一项新的、非创伤性的方法 ,作为一项冠状动脉疾病 (ＣＡＤ)的诊断性检查 ,它日益被提倡。在其临床用途被证实之前 ,必须更好的确定ＥＢＣＴ的总体准确性。目的 :评估ＥＢＣＴ诊断阻塞性ＣＡＤ的准确性。数据来源 :1979年 1月～ 2 0 0 0年 2月 2 9日期间检索了采用ＭＥＤＬＩＮＥ和ＣｕｒｒｅｎｔＣｏｎｔｅｎｔ数据库、图书及专家评议的英语文献。数据的选择 :纳入研究者要求 :①将ＥＢＣＴ作为诊断性检查 ;②所报道的病例应有真阳性、假阳性、真阴性、假阴性结果的绝对数 ;③冠…