不同状态人体牙槽骨的弹性性质

人体下颌牙槽骨皮质骨是各向异性复合生物材料,组织结构上类似于胶原羟磷灰石纤维增强的单向纤维增强复合材料。本文应用电测法测试了不同状态人体下颌牙槽骨皮质骨在平面应力状态下的各向异性弹性常数。     

Reaction of surrounding gingiva to permucosal implants of dense hydroxyapatite in dogs

Experimental and histological studies on the reaction of surrounding gingiva to permucosal implants of dense calcium hydroxyapatite were carried out in dogs. Epithelial attachment and connection of supra-alveolar collagen fibres to the implant surface seemed to form a biological seal around implants similar to that around natural teeth. However, excellent oral hygiene is very important for the maintenance of this biological seal.     

In vitro histamine release induced by radiocontrast media and various chemical analogs in reactor and control subjects

The factors governing in vitro basophil histamine release induced by radiocontrast material (RCM) were evaluated by the use of two RCMs (diatrizoate and metrizamide) and three structural analogs of RCM (benzoic acid, diaminobenzoic acid, and 3-acetamidobenzoic acid) in basophil histamine-release studies. Diatrizoate was chosen because it is a commonly used RCM and is routinely administered as a hypertonic drug (958 mOsm/kg or greater). Metrizamide is a newly synthesized RCM and is routinely administered in isotonic form (approximately 280 mOsm/kg). The analogs were used in hope of identifying any structure-function relationship that might exist between RCMs and the activation of a proposed basophil membrane receptor responsible for the induction of de granulation. In addition, results in a control group of normal subjects were compared with those in a group of patients who had experienced anaphylactoid reactions to intravenous RCM. Basophils from both groups were incubated with diatrizoate and metrizamide to assess their relative sensitivity to these drugs. Both metrizamide and diatrizoate induced in vitro histamine release. Therefore hypertonicity is not an absolute requirement for RCM-induced in vitro basophil de granulation. Although there was a trend far reagents without a prosthetic group at position 5 on the benzene ring (especially 3-acetamidobenzoic acid) to induce more release of histamine than reagents with such a prosthetic group, differences between these reagents did not reach statistical significance. Therefore no clearcut structure-function relationship could be demonstrated. “Reactor” subjects released significantly-larger percents of their intracellular histamine than did “nonreactors” (p < 0.05). Degranulated cells retained their ability to exclude trypan blue, an observation suggesting that RCM-induced histamine release does not involve cell death.     

不同跟腱修复材料特性的临床意义

目的　跟腱断裂术后制动弊端多 ,而早期功能锻炼优点明确 ,探讨各种缝合材料在打结后材料力学特性及滑结情况 ,为临床创新设计 ,术后无须制动的缝合组合提供依据。方法　将不同型号薇乔线 (CV)、慕丝线 (Mersilk)、攀状尼龙线 (Nylon)、普迪思 (PDS)各 1 6条剪断后各打 4个结 ,进行材料力学特性测试。结果　缝合材料的最大载荷、刚度、强度、比能分别为 :PDS >CV >Nylon >Mersilk(P <0 .0 5 )。结论　尽管PDS肌腱缝合线易滑结 ,但 1 0 -PDS ,1 0 -CV、1 0Nylon作端对端跟腱修复强度足够 ,相应 5 0PDS、5 0CV缝合材料作腱周修复也可选择 ,且打 4个以上结可靠。尽管Mersilk不易滑结 ,但不适合跟腱修复。不过好的缝合材料应选择最佳的缝合方法才更有临床意义     

异种骨内固定器力学性能的实验研究

目的了解牛骨材料及其构件的力学强度[抗拉、抗压、抗折(弯曲)和抗扭(剪切)强度].方法将材料分为天然、处理和构件(即产品)三组并制成标准试件,用规定设备按标准方法进行检测.结果(1)牦牛股骨拉伸、压缩、抗折、扭转极限应力分别为106.35±3.45、127.60±2.65、225.9±4.1、53.45±1.55(MPa),胫骨拉伸、压缩、抗折、扭转极限应力分别为114.96±1.46、184.75±3.25、211.35±2.45、51.9±0.5(MPa).湖区水牛胫骨拉伸、压缩、抗折、扭转极限应力分别为1 28.1±11、195.8±9.4、167.4±1 2.7、54.25±0.75(MPa).(2)E0气薰灭菌对牛骨材料的力学性能无明显影响,幅照灭菌对牛骨材料的力学性能稍有影响.(3)处理后,牛骨螺钉、圆钉的抗折强度较材料有所降低,而抗拉强度、抗压强度、抗扭强度变化不大.结论牛骨是一种力学性能良好,适合制作内固定构件的高强度生物材料.     

Interaction of biodegradable β-whitlockite ceramics with bone tissue: An in vivo study

The biodegradation of different porous β-whitlockite materials are studied by in vivo experiments, radiographie follow-ups and light microscopy observations. The materials were implanted in rabbit tibiae for 16 mnth. Micropores play an important role in the biodegradation rate. The resorbing materials evoke an inflammation with plasma cells. The resorption starts in the medulla, and the phagocytosed particles are removed to the lymph nodes. Normal bone function can be restored after all the implant material is resulted.     

Transcutaneous electrical stimulation and vibration of neck muscles in neglect

Four neglect patients without visual field defects, one with a lesion of the right basal ganglia and three with a right, predominantly parietal lesion, were examined with a cancellation and a copying task before, during and after neck muscle vibration, during transcutaneous electrical stimulation of neck muscles and during vibration of hand muscles on the left side. In all patients, neck muscle vibration improved task performance, while transcutaneous electrical stimulation and hand vibration had little or no effect. The present results demonstrate that the effect of neck muscle vibration cannot be explained as arousal and activation due to unspecific sensory stimulation on the contralesional side of the body. They rather argue for the assumption that the compensatory effect of neck muscle vibration on neglect is an effect induced by the predominant activation of afferent Ia nerve fibres and their specific contribution to the central representation of egocentric space.     

一种新型18°×4扇形网织红细胞计数窥盘

目的研制一种新型18°×4扇形网织红细胞计数窥盘。方法使用安瓿刀在玻片上刻制,再与国际血液学标准化委员会(ICSH)推荐的Miller窥盘进行网织红细胞对比分析。结果新型网织红细胞计数窥盘和ICSH推荐的Miller窥盘的准确度是一致的,但新型网织红细胞计数窥盘的精密度显著优于ICSH推荐的Miller窥盘。其参考范围也与其他报道一致。结论新型网织红细胞计数窥盘做法简单,不需特殊设备,值得推广应用。     

Use of a new mixture for embolization of intracranial vascular malformations

Summary The internal carotid artery system in swine has a special anatomic configuration similar to a brain arterial-arterial malformation. The internal carotid artery breaks up into a multitude of fine channels (rete mirabile) situated at the base of the skull on the side of the hypophysis. This anatomic arterial model was used to analyze acute and chronic angiographic and histological changes after occlusion of the rete mirabile with I) avitene, II) avitene, and 50% ethanol, III) avitene, 30% ethanol and Polyvinyl alcohol, IV) avitene 50% ethanol and Polyvinyl alcohol, V) IBCA and VI) silk. Histopathological changes observed in the rete mirabile six weeks following occlusion demonstrated that a mixture of avitene, 30% ethanol and Polyvinyl alcohol and IBCA produced the best anatomic results. Embolization with avitene, PVA and ethanol induced a more bland histological reaction than the one observed with IBCA. Preliminary clinical experience with this mixture is reassuring in those cases in which the AVM was surgically resected. The partially thrombosed AVM was easily depressed and compressed by the neurosurgeon allowing for satisfactory hemostasis in and around the nidus of the AVM.This paper was presented in part at the International Symposium on Cerebral Stroke, Sendai, Japan, 1987     

Re‐evaluation of normative electronystagmography data in healthy ageing

Previous work by our group questions the validity of existing electronystagmography ( eng ) reference ranges in the elderly. We aim to establish valid reference ranges for eng in people over 65 on the Nicolet Nystar Plus system. Ninety‐six healthy asymptomatic subjects over 65 underwent eng , including spontaneous and positional nystagmus, saccades, smooth pursuit, optokinetic nystagmus and bithermal calorics; 95% reference ranges with confidence intervals were calculated. The newly determined reference ranges were far wider than those provided by the eng equipment manufacturer for eight out of 11 parameters (all P < 0.001). Vestibular function is known to deteriorate and become more variable with age. The failure to reflect this change in currently used reference ranges may have contributed to the high rates of vestibular disease reported in some series of dizzy elderly patients. Clinical interpretation of eng depends on valid reference ranges.