Platelet spherocytosis: a new bleeding disorder

The present study evaluated a child with thrombocytopenia and a rare congenital bleeding disorder associated with platelet spherocytosis. Differential interference phase contrast microscopy (DIC) revealed that his platelets were spherical in form. Examination of thin sections in the electron microscope showed that his platelets were nearly devoid of microtubules (MT) and microtubule coils (MTC) that support the discoid shape in 100% of normal platelets. Immunofluorescence with a monoclonal antibody to tubulin, the precursor protein of MT, revealed bright rings in normal cells and diffuse fluorescence of patient platelets. The brightness of the fluorescence emitted by patient platelets was comparable to the diffuse fluorescence of normal platelets after chilling to dissolve intact MT, suggesting normal and patient cells contained comparable amounts of tubulin. Exposure of patient platelets to Taxol, an agent that stabilizes and induces MT, caused MT formation in 82% of patient platelets and MTC development in 11%, resulting in their conversion to discs. Glycoproteins GPIIb/IIIa and GPIb were present on patient platelets, and the cells contained normal numbers of dense bodies, ruling out storage pool disease. The patient's platelets adhered to and spread normally on glass but failed to undergo rapid, irreversible aggregation when stirred with agents that produced a complete response in normal discoid platelets, even when the patient's platelets were concentrated. The poor response of spherical platelets was associated with failure to become irregular and extend long filopodia. Thus, the spherical shape of patient platelets may contribute to the thrombocytopenia and to the clinical bleeding symptoms.     

Evaluation of a MR-quadrupole imaging coil for spinal interventions in a vertical 1.0 T MRI

The in vivo pain treatment was successfully performed with the patient in a prone position. The PD-weighted TSE with echo time = 10 ms rendered contrast-to-noise-ratio values of 27 ± 10 for needle/fat, 1.6 ± 5 for needle/muscle, and 4 ± 4.7 for needle/nerve tissue. The mean diameter of the needle artifact was 1.2 ± 0.2 mm. In the T(1)-weighted gradient echo, the needle's artifact diameter was 6 ± 2 mm; the needle's contrast-to-noise ratio relative to muscle tissue was 4 ± 2, 7.6 ± 1.5 for needle/fat, and 5 ± 1 for needle/nerve tissue. With the PD-weighted TSE (echo time = 10 ms) and the T(1)-weighted gradient echo, the needle was imaged reliably throughout the intervention. The butterfly surface coil is feasible for the guidance of spinal interventions in a prone patient.     

Ideal current patterns yielding optimal signal-to-noise ratio and specific absorption rate in magnetic resonance imaging: computational methods and physical insights

At high and ultra-high magnetic field strengths, understanding interactions between tissues and the electromagnetic fields generated by radiofrequency coils becomes crucial for safe and effective coil design as well as for insight into limits of performance. In this work, we present a rigorous electrodynamic modeling framework, using dyadic Green's functions, to derive the electromagnetic field in homogeneous spherical and cylindrical samples resulting from arbitrary surface currents in the presence or absence of a surrounding radiofrequency shield. We show how to calculate ideal current patterns that result in the highest possible signal-to-noise ratio (ultimate intrinsic signal-to-noise ratio) or the lowest possible radiofrequency power deposition (ultimate intrinsic specific absorption rate) compatible with electrodynamic principles. We identify familiar coil designs within optimal current patterns at low to moderate field strength, thereby establishing and explaining graphically the near-optimality of traditional surface and volume quadrature designs. We also document the emergence of less familiar patterns, e.g., involving substantial electric--as well as magnetic-dipole contributions, at high field strength. Performance comparisons with particular coil array configurations demonstrate that optimal performance may be approached with finite arrays if ideal current patterns are used as a guide for coil design.     

Varicocele embolization: Anatomical variations of the left internal spermatic vein and endovascular treatment with different types of coils

Purpose

To present anatomical variations of left internal spermatic vein and a comparison between treatments with hydrogel-coated and non-coated platinum coils in patients with varicocele.

颈内动脉海绵窦瘘的栓塞治疗

目的　进一步探讨颈内动脉海绵窦瘘 (CCF)血管内栓塞治疗的方法及临床价值。方法　在DSA监视下 ,采用法国Balt公司的同轴可脱性球囊技术 ,对 12例CCF患者进行了可脱性球囊栓塞治疗。结果　一次完全性地栓塞了颈内动脉瘘口 ,又保持了颈内动脉通畅 ,大脑前、中动脉显示清晰者 11例 ,占 92 % ;术后临床症状和体征完全消失。结论　采用可脱性球囊血管内栓塞是治疗CCF的最好方法 ,其操作简单 ,安全可靠 ,疗效好 ,值得进一步推广。     

Why do Electromagnetic Pulses Enhance Bone Growth?

The excitation probability of substrate molecules involved in the production of growth factors influencing the division of chondrocytes in the growth layer of bone under the influence of pulsed electromagnetic fields is studied theoretically in a quantum mechanical model calculation. In this model matrix elements and anti-bonding energy levels are assumed known and the dynamics of the interaction with pulsed electromagnetic fields is derived. The derivation makes it clear that continuous pulsing or large driving currents can overwhelm local diffusive transport to the growth plane resulting in a loss of its enhancement properties. Optimal locations within a pair of Helmholtz coils for enhancement of bone growth are also investigated and found to be close to the coils. The work presented here is believed to be the first derivation in a model calculation of a physical basis for the effects of pulsed electromagnetic fields on bone growth and fusion.     

DCS栓塞治疗颅内动脉瘤

目的总结使用水解可脱铂金弹簧圈系统（DCS）栓塞治疗颅内动脉瘤的经验与体会。方法采用神经介入方法、应用DCS系统栓塞治疗11例13枚颅内动脉瘤。结果用DCS系统对11例患者13枚颅内动脉瘤进行了栓塞，完全栓塞（〉95%）7个，大部分栓塞（80％～95％）5个，并发动脉瘤破裂1例，外科手术后痊愈，1例弹簧圈脱出到远端小动脉，经抗凝治疗未发生明显并发症。结论使用DCS系统栓塞治疗颅内动脉是一种安全、可靠、有效的治疗方法。     

颅内动脉瘤的血管内栓塞治疗

目的评估应用电解可脱性弹簧圈（GDC）及水解可脱铂金弹簧圈（DCS）栓塞治疗颅内动脉瘤的临床疗效，探讨手术时机及术中操作注意事项。方法采用GDC及DCS对23例颅内动脉瘤患者进行动脉瘤囊内栓塞，包括前交通动脉瘤5个，后交通动脉瘤6个，颈内动脉瘤7个，大脑中动脉瘤3个，椎基底动脉瘤2个；其中1例颈内动脉巨大动脉瘤栓塞2次，3例宽瘤颈动脉瘤采用血管内球囊辅助技术（Remodeling technique）或血管内支架（Neuroform）置入后行介入栓塞治疗。结果23例动脉瘤均成功栓塞，按动脉瘤的填塞程度分为：完全填塞20例，不完全填塞3例；2例巨大动脉瘤行载瘤动脉栓塞；术后无血栓形成及血栓性栓塞并发症，亦无神经功能障碍、瘫痪和死亡等永久性并发症；1例颈内动脉巨大动脉瘤在栓塞后24个月行造影随访发现局部复发，再次行动脉瘤栓塞治疗。随访2-42个月，全组术后均无出血或再出血。结论GDC及DCS栓塞颅内动脉瘤是一种安全、可靠、有效的治疗方法，根据动脉瘤病情联合运用多种栓塞技术有助于提高动脉瘤栓塞的治愈率、降低并发症。     

颅内破裂动脉瘤微弹簧圈栓塞治疗31例

目的:探讨微弹簧圈栓塞颅内破裂动脉瘤。方法:采用介入治疗颅内破裂动脉瘤微弹簧圈的栓塞。结果:30例病人康复出院,其中1例左下肢不全瘫,1例术后死亡。结论:颅内破裂动脉瘤,急诊微弹簧圈栓塞效果佳,致死、致残率极低。