骶骨螺钉经上终板与经前皮质固定的生物力学比较

目的测试骶骨螺钉经上终板固定技术的生物力学性能,并与经前皮质固定技术比较。方法取17具新鲜成年男性骶骨标本,两侧分别采用螺钉经上终板固定和经前皮质固定技术。经前皮质固定的螺钉指向前内侧,平行于终板;经上终板固定的螺钉指向前内侧,矢状面上向头侧成30°～35°角,钉尖对向S1上终板的前部。植入螺钉时测定最大扭矩;通过模拟生理应力进行疲劳试验,测定固定刚度变化和拔出力。结果经上终板固定组螺钉最大扭矩为(3.18±0.49)Nm,经前皮质固定组为(1.98±0.76)Nm, 差异有非常显著性(P< 0.01),经上终板固定组比经前皮质固定组高60.6%; 经上终板固定组拔出力为(1457±276)N,经前皮质固定组为(1122±364)N, 差异有显著性(P< 0.05),经上终板固定组比经前皮质固定组高29.9%;在循环负载过程中,两组刚度在负载早期(前5000个循环)均明显下降,然后趋于平稳,经上终板固定组的最后刚度高于经前皮质固定组(P< 0.05)。两组中螺钉的最大扭矩与拔出力均有显著相关性,相关系数分别为0.94和0.95(P< 0.01)。结论骶骨螺钉经上终板固定技术与经前皮质固定技术相比有一定的力学优越性。     

Dorsal lunate tilt (DISI configuration): sign of scaphoid fracture displacement

Excessive dorsiflexion (dorsal tilting) of the lunate on a lateral wrist radiograph can be an important sign of carpal injury. Lunate dorsiflexion is a well-recognized sign of an intercarpal ligamentous injury pattern known as dorsal intercalated segment instability (DISI). It is less well recognized that excessive dorsal tilting of the lunate (DISI configuration) can also be produced by displacement of a scaphoid waist fracture. Since the management and prognosis of displaced scaphoid fractures may be quite different from those for nondisplaced fractures, radiologists can make an important contribution by recognizing dorsal tilting of the lunate and appreciating that it may be an important, indirect sign of scaphoid fracture displacement, which may not be directly visualized with standard wrist radiography. In this setting, computed tomography or complex motion tomography may be helpful for further evaluation of the scaphoid fracture.     

双波长一元线性回归分光光度法同时测定复方氨基比林注射液中三组分含量

本文依据一组含有不同比例待测和干扰组分的标准混合液的吸收值,采用一元线性回归方法,在选择最佳测定波长对的同时建立标准工作曲线方程,使其更符合实际作品测定时的情况,提高了结果的精度和可靠性,并使计算量和实验工作量得以降低。应用于复方氨基比林注射液中三组分氨基比林、安替比林和巴比妥的同时测定,其平均回收率分别为99.8%,100.4%和99.8%,变异系数分别为0.59,1.48和1.05,结果优于卡尔曼滤波法、偏最小二乘法和目标因子分析法。     

Human T cell responses against the major cysteine proteinase (cruzipain) of Trypanosoma cruzi: role of the multifunctional alpha 2- macroglobulin receptor in antigen presentation by monocytes

Chagas' disease patients (CDP) develop both humoral and cellular immune responses against the major cysteine proteinase (cruzipain) from Trypanosoma cruzi. Here we demonstrate that complexes formed by cruzipain and alpha 2-macroglobulin (alpha 2M) are efficiently internalized by human monocytes, and that this process results in enhanced presentation of cruzipain peptides to CD4+ T cells from CDP. Purified or serum alpha 2M binds to polymorphic cruzipains, but only a fraction of the proteinases become covalently linked. Once bound to alpha 2M, fluorescein-labeled cruzipain (FITC-cruzipain) or [125I]cruzipain were more efficiently internalized by normal peripheral blood mononuclear cells (PBMC) or monocytes; this effect was abolished by (I) pre-treating the cells with receptor-associated protein (rRAP), a known antagonist the of alpha 2M receptor (alpha 2MR/LRP), and (II) inactivating [125I]cruzipain's active site prior to the reaction with alpha 2M, indicating that the exposure of receptor binding sites on alpha 2M complexes required bait region cleavage. We then sought to determine if the alpha 2MR/LRP-dependent uptake of alpha 2M:cruzipain by monocytes resulted in increased CD4+ T cell responses of PBMC-CDP (n = 13). These effects were only revealed after depletion of CD19+ B lymphocytes from PBMC-CDP; the threshold of T cell stimulation was far lower in cultures stimulated with alpha 2M:cruzipain, as compared to antigen alone. Myocardial specimens from CDP with chronic myocardiopathy (three necropsies) were analyzed by immunohistochemistry with mAb anti-cruzipain or anti-alpha 2MR/LRP (CD81+). Extracellular depots of cruzipain were localized amidst inflammatory mononuclear infiltrates, part of which contained CD91+ macrophage-like cells. Ongoing studies should clarify if T. cruzi cysteinyl proteinases play a role in the pathogenesis of Chagas' heart disease.      

Skeletal Class III correction in permanent dentition using reverse twin block appliance and fixed mechanotherapy

The orthodontic management of patients with Class III malocclusion poses numerous prognostic and treatment challenges to the clinician. Various removable, orthopaedic, myofunctional and fixed appliances have been recommended for the correction of Class III malocclusion. The Reverse Twin Block (RTB) is a simple and well tolerated appliance which has often been used for the early management of such cases in mixed dentition. Cases reporting use of RTB in permanent dentition are however, limited. This article presents an insight into the encouraging results of reverse twin block (RTB) appliance used in conjunction with fixed mechanotherapy for the successful treatment of a 12-year-old patient presenting with skeletal Class III malocclusion and a concave facial profile. The RTB appliance helped establish a favourable environment for unrestricted maxillary growth, at the same time redirecting the mandibular growth to a clockwise direction and correcting the incisal relationship. The favourable treatment outcome and long-term stability achieved substantiates the feasibility of RTB appliance in mild to moderate skeletal Class III malocclusions in permanent dentition cases.     

Reconstructive challenges in war wounds

War wounds are devastating with extensive soft tissue and osseous destruction and heavy contamination. War casualties generally reach the reconstructive surgery centre after a delayed period due to additional injuries to the vital organs. This delay in their transfer to a tertiary care centre is responsible for progressive deterioration in wound conditions. In the prevailing circumstances, a majority of war wounds undergo delayed reconstruction, after a series of debridements. In the recent military conflicts, hydrosurgery jet debridement and negative pressure wound therapy have been successfully used in the preparation of war wounds. In war injuries, due to a heavy casualty load, a faster and reliable method of reconstruction is aimed at. Pedicle flaps in extremities provide rapid and reliable cover in extremity wounds. Large complex defects can be reconstructed using microvascular free flaps in a single stage. This article highlights the peculiarities and the challenges encountered in the reconstruction of these ghastly wounds.KEY WORDS: Delayed reconstruction, reconstructive challenges, war wound, wound debridement     

Beta thalassemia in Melanesia: association with malaria and characterization of a common variant (IVS-1 nt 5 G----C)

Data on the distribution of beta thalassemia among over 6,000 Melanesians reveals a major difference in the carrier rates between populations in the malarious coastal regions of New Guinea and those living in the historically malaria-free Highlands. The island of Maewo in Vanuatu has a particularly high incidence of beta + thalassemia associated with a single restriction enzyme haplotype. Direct cloning into a plasmid vector and sequence analysis demonstrate that the mutation is a G to C transversion at position 5 of intron 1 of the beta- globin gene. Oligonucleotide probe surveys indicate that this variant accounted for all cases of beta thalassemia studied from Maewo. It is also common in coastal Papua New Guinea where haplotype and oligonucleotide probe data suggest that the molecular basis of beta thalassmia is more heterogeneous.