Internal derangements of the temporomandibular joint: findings in the pediatric age group

Findings in 31 pediatric patients with pain and dysfunction of the temporomandibular joint (TMJ) are reported. The average age was 14 years (range, 8-16) and the average duration of symptoms was 21.4 months (range, 3 mo.-5 yr.). Internal derangements were found in 29 patients (94%) and degenerative arthritis in 13 (42%). In 12 patients (39%), the problem could be traced to an injury to the jaw. Secondary condylar hypoplasia was associated with the meniscal abnormality in 3 patients (10%). Further awareness of internal derangements of the TMJ in the pediatric population should permit greater recognition of their etiology. It is important that treatment be initiated as soon as possible, not only to minimize the development of osseous disease in young adults but also to prevent facial growth deformities.     

全髋关节置换术中钴-铬股骨头不同磨损部位的摩擦学特性

 通过使用原子力显微镜检查(atomic force microscopy,AFM)计算表面粗糙度和摩擦系数的方法,对工程和生物材料的摩擦学特性进行研究。尽管之前的大量研究对全髋关节置换术中不同承重材料的摩擦系数进行了报告,但却没有关于全髋关节置换术术中轴承材料的表面粗糙度和摩擦系数的关系的报道。此外,钴-铬股骨头不同磨损部位的摩擦学特性尚不明确。因此,本研究对全髋关节置换术后 10年钴-铬股骨头发生严重磨损及轻微磨损部位的表面粗糙度、摩擦系数和硬度之间的关系进行研究。钴-铬股骨头的平均维氏硬度为(380.7±11.3) HV。在 AFM扫描的 25滋m伊25滋m面积内,严重磨损和轻微磨损部位的摩擦系数分别为 0.229±0.054和 0.243±0.059,两者差异无统计学意义(P=0.449)。严重磨损部位的表面粗糙度[Rq=(96.5±26.2) nm]与轻微磨损部位[Rq=(17.7±4.2) nm]的差异有统计学意义(P <0.0001)。本研究结果显示院钴-铬股骨头的摩擦特性与其表面粗糙度没有明显关系,为金属植入材料表面特性的改善提供了依据。     

Bupivacaine-induced cellular entry of QX-314 and its contribution to differential nerve block

Background and Purpose: Selective nociceptor fibre block is achieved by introducing the cell membrane impermeant sodium channel blocker lidocaine N-ethyl bromide (QX-314) through transient receptor potential V1 (TRPV1) channels into nociceptors. We screened local anaesthetics for their capacity to activate TRP channels, and characterized the nerve block obtained by combination with QX-314.Experimental Approach: We investigated TRP channel activation in dorsal root ganglion (DRG) neurons by calcium imaging and patch-clamp recordings, and cellular QX-314 uptake by MS. To characterize nerve block, compound action potential (CAP) recordings from isolated nerves and behavioural responses were analysed.Key Results: Of the 12 compounds tested, bupivacaine was the most potent activator of ruthenium red-sensitive calcium entry in DRG neurons and activated heterologously expressed TRPA1 channels. QX-314 permeated through TRPA1 channels and accumulated intracellularly after activation of these channels. Upon sciatic injections, QX-314 markedly prolonged bupivacaine''s nociceptive block and also extended (to a lesser degree) its motor block. Bupivacaine''s blockade of C-, but not A-fibre, CAPs in sciatic nerves was extended by co-application of QX-314. Surprisingly, however, this action was the same in wild-type, TRPA1-knockout and TRPV1/TRPA1-double knockout mice, suggesting a TRP-channel independent entry pathway. Consistent with this, high doses of bupivacaine promoted a non-selective, cellular uptake of QX-314.Conclusions and Implications: Bupivacaine, combined with QX-314, produced a long-lasting sensory nerve block. This did not require QX-314 permeation through TRPA1, although bupivacaine activated these channels. Regardless of entry pathway, the greatly extended duration of block produced by QX-314 and bupivacaine may be clinically useful.     

MEASUREMENT OF ROOT CANAL LENGTH – USE OF AN ELECTROMETRIC DEVICE

The measurement of root canal length is a pre-requisite for successful pulpectomy. The conventional manual and radiographic methods are not very accurate. In the present study, odontometer was used [Group B) to assess its efficacy over the conventional methods (Group A) for recording root canal length. In group A, 36 teeth were treated with pulpectomy while in group B, 51 teeth were managed by the same treatment. It was observed that post operative complications in group B were significantly less (p < 0.05). The odontometer proved to be an excellent device for rapid and accurate measurement of root canal length.KEY WORDS: Pulpectomy, Root canal length, Odontometer     

Intrathecal administration of nitroxides as potential contrast agents for MR imaging

The diagnosis of various disorders of the cerebrospinal fluid (CSF) with magnetic resonance (MR) imaging may require the intrathecal administration of a paramagnetic contrast agent. Furthermore, the CSF route provides direct access to the brain, circumventing the blood-brain barrier. Three nitroxides, two charged and one uncharged, were administered intrathecally to dogs to assess their potential as contrast agents for MR imaging of the CSF. Nitroxide concentrations and proton T1 values were measured in samples of CSF removed at various times after nitroxide administration, and pharmacokinetic curves were constructed. The charged nitroxides had considerably longer half-lives than the uncharged compound. On in vivo MR imaging of the CSF (surrounding the upper cervical cord and brain stem) in one dog, use of a charged nitroxide as contrast agent led to considerably higher CSF signal intensity than was observed in the nonenhanced, baseline T1-weighted images. This effect was achieved at low doses (20 mumol) and sustained for at least 90 minutes. The intrathecal use of nitroxides as contrast agents for MR imaging warrants continued investigation.     

Spinal compression fractures in osteoporotic women: patterns and relationship to hyperkyphosis

A prospective study of thoracic and lumbar spinal fracture distribution and its relationship to thoracic kyphosis was performed in 87 women with osteoporosis. Anterior wedge fractures were most commonly seen in the midthoracic spine and about the thoracolumbar junction, whereas central compression fractures were most common from the first to the fourth lumbar levels. Solitary wedge fractures did not occur above the seventh thoracic vertebra, suggesting that a cause other than osteoporosis must be suspected in any patient with an isolated high thoracic fracture. Analysis of the spinal radiographs obtained in an additional 16 women without osteoporosis revealed that both forms of fracture were unusual in this small group with normal spinal mineralization. The number of anterior wedge fractures in the thoracic spine correlated (r = .546) with the degree of thoracic kyphosis. However, 19% of the women with no thoracic fractures still had thoracic hyperkyphosis. The authors conclude that the hyperkyphosis of osteoporotic women is related to anterior compression fractures but also has contributing nonskeletal factors.     

Attentional processing in cervical spine syndromes

Fifty-four patients suffering from "common whiplash" were compared with 28 patients complaining of cervical spine syndrome caused by rheumatism (Barré-Lieou syndrome). All patients underwent clinical interview and formal testing. Formal testing included personality profile, self ratings of cognitive impairment and well-being, and tasks on divided attention and speed of information processing. In the "common whiplash" group higher relative incidences of adjustment disorder were found. In both groups scoring for divided attention was low. With regard to self-ratings, the group suffering from Barré-Lieou syndrome hardly indicated any problems while the "common whiplash" group showed significant impairment. This difference of self-ratings was assumed to reflect the different modes of development of the investigated syndromes: in the group with cervical syndrome due to rheumatism the condition gradually developed giving the patient the possibility to adapt, while in the "common whiplash" group cervical pathology emerged abruptly by impact injury. Adaptation in the latter group was inadequate which in particular explains the appearance of adjustment disorders amongst "common whiplash" patients. Results indicated that headache due to cervical pathology is likely to be responsible for impaired attentional functioning of "common whiplash" patients.     

Update of radiosurgery at the Royal Adelaide Hospital

This is an update of the Royal Adelaide Hospital radiosurgery experience between November 1993 and December 2004 comprising 165 patients with 168 intracranial lesions. Including re‐treatment, there were 175 treatment episodes (163 radiosurgery and 12 stereotactic radiotherapy) at an average of 1.3 per month. The commonest lesions were acoustic neuroma (65), arteriovenous malformation (58), solitary brain metastasis (23) and meningioma (14). The clinical features, treatment details and outcome are described. Our results continue to be well within the range reported in the published work. Radiosurgery provides an elegant, non‐invasive alternative to neurosurgery and conventional external beam radiotherapy for many benign and malignant brain tumours.