Design and biomechanical study of a novel double-leaf proximal humeral locking plate / 医用生物力学

Objective To design a novel double-leaf proximal humeral locking plate for fixing greater and lesser tuberosities in complex proximal humeral fractures, and evaluate its fixing stability by biomechanical tests. Methods Twelve fresh-frozen humerus specimens with intact rotator cuff were randomly divided into two groups (Group A and Group B) to establish the same greater and lesser tuberosities fracture models. Specimens in Group A were fixed with the double-leaf proximal humeral locking plate, while specimens in Group B were fixed with the proximal humeral internal locking system (PHILOS) and tension band suture, and a 3.5-mm cannulated screw was added to stabilize the lesser tuberosity. The tensile test on subscapularis, infraspinatus and teres, supraspinatus as well as the load-to-failure test on greater and lesser tuberosities were performed on specimens in two groups. Results For subscapularis tensile tests, displacements under 150 N tensile stretch and after fatigue test in Group A were both significantly smaller than those in Group B (P0.05). For supraspinatus tensile tests, there were no statistical differences between Group A and B in displacements under 90 N tensile stretch and after fatigue test (P>0.05). For load-to-failure tests on lesser tuberosity, the failure load in Group A was significantly greater than that in Group B (P0.05). Conclusions Compared with the ordinary tension band suture plus cannulated screw for fixing lesser tuberosity, the novel double-leaf proximal humeral locking plate shows more obvious biomechanical stability, with the advantage of simultaneously fixing greater and lesser tuberosities. The research findings provide a new choice for the clinical treatment of complex proximal humeral fractures.

Design and biomechanical study of a novel double-leaf proximal humeral locking plate / 医用生物力学

Objective To design a novel double-leaf proximal humeral locking plate for fixing greater and lesser tuberosities in complex proximal humeral fractures,and evaluate its fixing stability by biomechanical tests.Methods Twelve fresh-frozen humerus specimens with intact rotator cuff were randomly divided into two groups (Group A and Group B) to establish the same greater and lesser tuberosities fracture models.Specimens in Group A were fixed with the double-leaf proximal humeral locking plate,while specimens in Group B were fixed with the proximal humeral internal locking system (PHILOS) and tension band suture,and a 3.5-mm cannulated screw was added to stabilize the lesser tuberosity.The tensile test on subscapularis,infraspinatus and teres,supraspi natus as well as the load-to-failure test on greater and lesser tuberosities were performed on specimens in two groups.Results For subscapularis tensile tests,displacements under 150 N tensile stretch and after fatigue test in Group A were both significantly smaller than those in Group B (P ＜ 0.05).For infraspinatus and teres tensile tests,there were no statistical differences between Group A and B in displacements under 150 N tensile stretch and after fatigue test (P ＞ 0.05).For supraspinatus tensile tests,there were no statistical differences between Group A and B in displacements under 90 N tensile stretch and after fatigue test (P ＞ 0.05).For load-to-failure tests on lesser tuberosity,the failure load in Group A was significantly greater than that in Group B (P ＜ 0.05),and the failure displacement in Group A was significantly smaller than that in Group B (P ＜ 0.05).For load-to-failure tests on greater tuberosity,there were no statistical differences between Group A and B in both the failure load and failure displacement (P ＞ 0.05).Conclusions Compared with the ordinary tension band suture plus cannulated screw for fixing lesser tuberosity,the novel double-leaf proximal humeral locking plate shows more obvious biomechanical stability,with the advantage of simultaneously fixing greater and lesser tuberosities.The research findings provide a new choice for the clinical treatment of complex proximal humeral fractures.

Effect of salvianolic acid A on anesthetized canine experimental myocardial infarction / 中国中药杂志

Salvianolic acid A (SAA), one of the major active water-soluble salvianolic acids of traditional Chinese medicine Salvia miltiorrhiza Bunge, has been reported to be effective on anti-myocardial ischemia, anti-oxidation and anti-thrombus. This study aimed to investigate appropriate administration route on dogs with acute myocardial ischemia(AMI). Twenty-four dogs were randomized into four groups (n=6), model, oral administration of SAA (8 mg•kg⁻¹), intravenous administration of SAA (4 mg•kg⁻¹), intravenous administration of Herbesser(0.5 mg•kg⁻¹) as positive drug group. AMI model was established by ligating left anterior descending coronary arteries(LAD) of dogs. Changes of ST segment were determined by epicardial electrocardiogram(ECG), coronary blood flow (CBF) and myocardial oxygen consumption were measured by ultrasonic Doppler flow meter, serum creatine kinase (CK) and lactate dehydrogenase (LDH) were observed by fully automatic biochemical analyser. Myocardial infarct size was assessed by nitro blue tetrazolium (NBT) staining. Both oral and intravenous administration of SAA reduced the myocardial infarct area/left ventricle area significantly [(16.73±6.52)% and (13.19±2.38)%, compared with (24.35±4.89)% in model group, P<0.01). Oral administration of SAA improved the ECG performance of Σ-ST from 30-190 min after ischemia (P<0.05-0.01), while intravenous SAA had a rapid onset (10-190 min after ischemia, P<0.05-0.01). Compared with model group, oral and intravenous SAA both decreased serum CK and LDH significantly (P<0.05-0.01), while the difference of intravenous administration is more significant. SAA protects myocardium in canine experimental myocardial infarction models. Intravenous administration of SAA alleviates myocardial infarction with greater significance than oral route.

Confocal Microscopy Evaluation of Meibomian Gland Dysfunction in Dry Eye Patients with Different Symptoms / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Dry eye patients suffer from all kinds of symptoms. Sometimes, the clinical signs evaluation does not disclose any obvious difference in routine examination; in vivo confocal microscopy (IVCM) is a powerful tool for ocular surface disease. This study aimed to clarify meibomian gland (MG) alterations in dry eye patients with different symptoms and to compare the findings using IVCM.</p><p><b>METHODS</b>A total of sixty patients were recruited, all subjected to Ocular Surface Disease Index (OSDI) and Salisbury Eye Evaluation Questionnaire (SEEQ), and questionnaires for the assessment of dry eye symptoms before clinical sign examinations were given to the patients. Finally, IVCM was applied to observe MG's structure. Statistical analysis was performed using the t-test, Mann-Whitney U-test and Spearman correlation analysis. The differences were statistically significant when P< 0.05.</p><p><b>RESULTS</b>In the severe symptom group, OSDI and SEEQ scores were significantly higher (P< 0.05) compared with the mild symptoms group. All other clinical sign examinations had no statistical difference in the two groups (P> 0.05). However, all the IVCM-observed data showed that patients with severe symptoms had more significant fibrosis in MG (acinar unit area 691.87 ± 182.01 μm2 for the severe, 992.17 ± 170.84 μm2 for the mild; P< 0.05) and severer decrease in the size of MG acinar units than those observed in patients with mild symptoms (MG acinar unit density [MGAUD] 70.08 ± 18.78 glands/mm2, MG acinar unit longest diameter [MGALD] 51.50 ± 15.51 μm, MG acinar unit shortest diameter [MGASD] 20.30 ± 11.85 μm for the severe, MGAUD 89.53 ± 39.88 glands/mm2, MGALD 81.57 ± 21.14 μm, MGASD 42.37 ± 14.55 μm for the mild;P< 0.05). Dry eye symptoms were negatively correlated with MG confocal microscopic parameters and positively correlated with conjunctival inflammatory cells and Langerhans cells (P< 0.05).</p><p><b>CONCLUSIONS</b>IVCM application provides a strong support to differentiate dry eye patients with different symptoms: meibomian gland dysfunction (MGD) plays a pivotal role in dry eye aggravation, and using IVCM to observe MG fibrosis, changes in size and density of MG as well as status of inflammation cells can help not only correctly diagnose the type and severity of dry eye, but also possibly prognosticate in routine eye examination in the occurrence of MGD.</p>

Studies on therapeutic effects of zhenzhu qishi wan on stroke and hypertension of SHRsp / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of Zhenzhu Qishi Wan on blood pressure(BP), body weight(BW), stroke and survival rate of stroke-prone spontaneously hypertension rats(SHRsp).</p><p><b>METHOD</b>8-week-old SHRsp was randomly divided into three groups: control group, Zhenzhu Qishi Wan prevention group and therapy group (n = 10). SHRsp of prevention group were treated with Zhenzhu Qishi Wan by ig 150 mg.kg-1 per day for 6 weeks, and therapy group were given the same treatment two weeks later. Behavior and stroke were observed everyday; BW were weighted every week; BP were estimated every 2 weeks. Time of the first cerebral seizure of SHRsp was recorded.</p><p><b>RESULT</b>Zhenzhu Qishi Wan had obvious preventive and therapeutic effect on genetic hypertension. The BP of prevention and therapy groups were significantly lower than that of control group (P < 0.05 [symbol: see text] P < 0.01). The drug ameliorated general behavior of SHRsp, BW of prevention group increased faster than that of control group(P < 0.05 or P < 0.01), and BW of therapy group were also heavier than that of control group at the age of 14 weeks(P < 0.05). When the experiment ended, 60% SHRsp of control group showed stroke and 20% of them were dead, while only 20% SHRsp in each of Zhenzhu Qishi Wan-treated groups showed stroke and none of them died.</p><p><b>CONCLUSION</b>Zhenzhu Qishi Wan had significant hypotensive effect, and some protective effect on the stroke caused by hypertension.</p>