上肢康复操在维持性血液透析患者中的应用研究

目的 评价上肢康复操在维持性血液透析患者中的应用效果。 方法 选取2021年10月—12月于山东省某三级甲等医院血液净化中心行维持性血液透析治疗的患者77例,按随机数字表分为试验组38例和对照组39例,试验组在常规护理的基础上进行上肢康复操训练,对照组只接受常规护理。分别比较干预前和干预3个月后两组的双手握力、肩关节活动度、动静脉内瘘血流量及非内瘘侧头静脉直径。 结果 试验组36例、对照组38例完成研究。干预前两组双手握力、肩关节活动度、动静脉内瘘血流量及非内瘘侧头静脉直径比较,差异无统计学意义（P>0.05）;干预后试验组与对照组比较,内瘘侧握力（t=-2.350,P=0.022）、非内瘘侧握力（t=-3.693,P<0.001）,内瘘侧肩关节外展（t=-2.468,P=0.016）、外旋（t=-5.167,P<0.001）、内旋（t=-2.059,P=0.043）,动静脉内瘘血流量（t=-2.020,P=0.047）、非内瘘侧头静脉直径（t=-5.229,P<0.001）均增加,差异具有统计学意义。 结论 上肢康复操训练有助于改善维持性血液透析患者的上肢功能及维护动静脉内瘘。     

Efficiency of twice weekly concurrent training in trained elderly men

This study compared the effects of different weekly training frequencies on the cardiovascular and neuromuscular adaptations induced by concurrent training in previously trained elderly. After 20 weeks of combined strength and endurance training, twenty-four healthy elderly men (65 ± 4 years) were randomly placed into two frequency training groups: strength and endurance training performed twice a week (SE2, n = 12); or, strength and endurance training performed three times per week (SE3, n = 12). The interventions lasted 10 weeks and each group performed identical exercise intensity and volume per session. Before and after the exercise training, one maximum repetition test (1RM), isometric peak torque (PT), maximal surface electromyographic activity (EMG), as well as muscle thickness (MT) were examined. Additionally, peak oxygen uptake (VO_2peak), maximum aerobic workload (W_max), first and second ventilatory thresholds (VT₁ and VT₂) were evaluated. There were significant increases in upper and lower-body 1RM, MT, VO_2peak, VT₁ and VT₂, with no differences between groups. There were no changes after training in maximal EMG and isometric peak torque. W_max was improved only in SE3. After 10 weeks of training, twice weekly combined strength and endurance training leads to similar neuromuscular and cardiovascular adaptations as three times per week, demonstrating the efficiency of lower frequency of concurrent training in previously trained elderly men.     

ZTA和Al2O3正畸托槽的研究

目的 分别评价ZTA(ZrO2增韧Al2O3)和Al2O3陶瓷的性能,探索一种适合制备正畸托槽的陶瓷材料.方法 选用ZrO2(3mol%Y2O3)和α-Al2O3粉体作为原料,利用热压铸成型工艺制备陶瓷托槽,在1600 ℃下烧结.将制得样品进行各方面的性能测试.结果 采用纯Al2O3制备的托槽抗弯强度远远低于ZTA复合陶瓷.结论 牙科正畸托槽可以选用具有较高抗弯强度的ZTA复合陶瓷作为原料.     

Midvastus approach in total knee arthroplasty: a randomized, double-blinded study on early rehabilitation

The medial parapatellar approach has become the standard technique in total knee arthroplasty (TKA). However, recent studies have reported superior results regarding functional recovery when using the midvastus approach. It was the aim of this study to evaluate the early functional outcome of both surgical techniques. In a prospective, double-blinded, randomized study, 50 patients for TKA were consecutively operated on either by the medial parapatellar or the midvastus approach. Exclusion criteria were defined as previous open knee surgery and leg deformity of more than 10° varus or valgus. TKA was performed in all patients by one surgeon using the same type of implants in both groups. Pain scores (VAS) were documented and follow-up data including quadriceps strength and proprioception were obtained 3 weeks and 6 weeks postoperatively. Both groups were comparable in preoperative demographic data. Postoperatively, patients in the midvastus group demonstrated significantly lower pain in rest (VAS: mean 2.25 vs. 3.03) and under movement (VAS: mean 2.92 vs. 3.13). Further, they showed superior isometric quadriceps strength at 3 weeks (41.4 vs. 27.6 Nm) and 6 weeks (47.6 vs. 35.5 Nm). Moreover, this group showed a superior postoperative proprioception, while the range of motion was similar in both groups. The midvastus approach offers advantages over the standard parapatellar arthrotomy, in the early rehabilitation period. No adverse effects were observed associated with this approach. Therefore, the midvastus approach should be considered as a valuable alternative in TKA.     

Resistive Training Maintains Bone Mineral Density in Postmenopausal Women

We examined the effects of a total body resistive training program (RT) on total and regional bone mineral density (BMD) in older women. Twenty-seven healthy postmenopausal women (mean age 62 ± 1 years) participated in a strength training program three times/week for 16 weeks. Strength was assessed before and after training by either one or three repetition maximum (1RM and 3RM) tests. Both upper and lower body strength significantly increased by 36–65% and 32–98%, respectively, after training. There was a small but significant decrease in body weight and body mass index after training (P < 0.05), with no change in the waist-to-hip ratio. BMD, assessed by dual-energy X-ray absorptiometry, did not change over the duration of the training period in the anterioposterior spine (L₂–L₄), femoral neck, Ward's triangle, and greater trochanter. BMD of the total body, lateral spine (B₂–B₄), and the regions of the radius (1/3 radius and ultradistal radius) also did not fall in subsets of these women. Muscular strength of both the leg and chest press were significantly associated with L₂–L₄, femoral neck, Ward's triangle, and greater trochanter BMD (range r = 0.57–0.84, all P < 0.005). Markers of bone turnover, namely, bone-specific alkaline phosphatase, osteocalcin, and urinary aminoterminal cross-linked telopeptide of type I collagen did not change significantly. In conclusion, a resistive training program maintains BMD and improves muscular strength in healthy, older women. This may be important in preventing the negative health outcomes associated with the age-related loss of bone density. Received 5 June 1996 / Accepted: 26 June 1997     

The repeated compression of powders

Powders were subjected to repeated compression in a tablet press, the ejection mechanism of which had been disconnected. The force detected at the upper punch was found to change with successive compressions, the magnitude of the change being dependent on the powder, the compressive force and the interval between compressions. Repeated compression also caused a change in tablet crushing strength. With compression intervals of 1.2 s, all substances showed an significant increase in strength. With longer time intervals, the increase was reduced and in some cases, a diminution in strength occurred.     

Rib structure and bending strength: An autopsy study

Mechanical rib testing and geometric analysis were explored as means of evaluating metabolic bone disease. Seventy-nine male patients were examined postmortem. Displacement rate at the loading point and patient age were important variables for which results had to be corrected. Like long bones, ribs apparently undergo progressive circumendosteal resorption with advancing age but unlike long bones, they show no evidence of continued subperiosteal apposition. Effects of selected individual diseases and of all diseases grouped by major organ system were analyzed. Most produced no discernible modification of rib volume, geometry or bending strength as quantified by modulus of rupture. Exceptions were myeloma and arthritis, where the bony material was weakened without remodeling or loss in volume.     

Relations between tensile impact properties and microstructure of compact bone

Summary Standardized human and beef femoral compact bone specimens were tested in tensile impact and the dynamic mechanical properties were determined. The microstructure of 45 beef and 47 human bone specimens were examined histologically to determine if there is a structural basis to account for strength differences in the bone samples. Strong negative correlations were obtained between the maximum stress and the percentage area of secondary osteons in each specimen. For human bone samples, the energy absorption capacity and the modulus of elasticity were also found to have strong negative correlations with the percentage area of secondary osteons present in each specimen. Linear regression equations were obtained describing the impact strength properties in terms of the percentage areas of secondary osteons and cavities in the samples.Fracture surfaces of the tested bone specimens were examined in a scanning electron microscope. Most surfaces exhibited a fairly rough texture indicating a quasi-cleavage type of failure. Fractographic analysis of bone fracture surface was helpful in understanding the micromechanics of bone fracture.Presented in part at the 21st Annual Meeting of Orthopaedic Research Society     

Strength of HLA-A,HLA-B,and HLA-DR mismatches in relation to short- and long-term kidney graft survival

The separate influence of HLA-A, HLA-B, and HLA-DR mismatches on short- and long-term kidney graft survival was analyzed in a series of over 40,000 recipients of first cadaver kidney transplants. As expected, during the early posttransplant period, HLA-DR mismatches had a stronger influence on graft survival than HLA-B mismatches, and HLA-A mismatches had a very small influence. Surprisingly, during the period from 6 months to 5 years post transplantation, all three HLA loci had approximately the same influence. When the graft survival computation was started at 100 % at 6 months, the difference between grafts with zero or two mismatches at the end of 5 years was 6 %, regardless of whether HLA-A, HLA-B, or HLA-DR antigens were analyzed. The influence of the three loci was additive so that the survival rate difference between transplants with zero or six mismatches for HLA-A, -B, -DR was 17 % at 5 years. We concluded that, although the HLA-A locus exerts only a weak influence during the early posttransplant course, its influence on long-term survival is comparable to that of HLA-B and HLA-DR. In order to obtain optimal long-term survival, all three loci must be considered in the donor-recipient matching procedure.     

Changes in contractile properties of muscle after strength training in man

Summary Thirty young male adults matched in two experimental groups (n=12) and a control group (n=6) were investigated before and after an 8-week strength training period. Group A trained with few repetitions and maximal loads, whereas group B had more repetitions with smaller loads. Both groups lifted the same total load during each training period, four times a week. Maximal voluntary strength (MVS) of a shot-put arm movement, muscular excitability and contractile properties (time to peak of contraction with threshold stimuli, half relaxation time) were measured in M. deltoideus and M. triceps brachii, C. longum, for two durations of stimulation. Increases of 14.8% (group A) and 12.2% (group B) in MVS were observed. Muscle excitability significantly increased in all types of training and both muscles. Significant shortening of the contraction time, dependent on the type of training, was observed in both studied muscles. It appears that the strength training in group A involved the fast fibers of both muscles, whereas in group B the training influence was less marked, and affected both fast and slow fiber types.