Central effects of paraoxon on haemodynamics in the cat

Summary Application of paraoxon into the left vertebral artery (8–80 g) or both the left and right vertebral artery (4–8 g) of the anaesthetized cat evoked dose-dependent depressor effects, whereas heart rate was not influenced significantly. Also after systemic administration of paraoxon (150–825 g·kg^–1), while peripheral muscarinic receptors were blocked, depressor effects were still observed. Dose-response curves for the depressor response to paraoxon were established. Infusion of low doses of dexetimide via the vertebral artery prevented the hypotensive action of paraoxon. The distribution of this antimuscarinic drug in the brain was investigated. The depressor effect of paraoxon can be attributed to both a decrease in peripheral resistance and cardiac output. Decerebration and midcollicular transection were carried out in order to elucidate the site and mechanism of action. The depressor effect of paraoxon seems to be mediated by a central mechanism of action located within the lower brain stem.It is concluded that stimulation of muscarinic receptors in the pontomedullary region gives rise to the observed changes in haemodynamic parameters. Muscarinic receptors in the hypothalamus seem to be of minor importance for the hypotensive action of paraoxon.     

Clinical significance of retrograde flow in the vertebral artery

Although retrograde vertebral artery flow was described over 100 years ago, its relationship to symptoms remains unclear. We documented 43 patients who were found by duplex scanning to have reverse flow in the vertebral artery. Of this group, seven patients (16%) were found to have symptoms described as typical for the subclavian steal syndrome. Nearly one-third were asymptomatic. Of the remaining patients, 13 (30%) presented with nonhemispheric symptoms while nine (21%) had hemispheric symptoms. Nine patients had to and fro flow in the vertebral artery. This variant was not found in subclavian steal patients but correlated with nonhemispheric symptoms. During follow-up (mean: 19 months) none of the asymptomatic patients became symptomatic, and there were no strokes or stroke-related deaths. Surgical procedures which restored antegrade vertebral artery flow did not necessarily improve symptoms of posterior circulation ischemia. In some patients improvement in posterior circulation symptoms was noted following carotid endarterectomy. It is concluded that retrograde flow in the vertebral artery is, per se, a benign entity. Accurate selection of surgical candidates remains imprecise. It will require not only identification of vertebrobasilar disease but as yet undefined tests to assure symptoms are due to these stenoses.     

Unusual fractures and dislocations of the axis vertebra

Seven percent of 400 patients with cervical spine fractures and/or dislocations had unusual lesions of the axis. The authors have analyzed axis injuries by review of radiographs and clinical data and have derived a classification of traumatic conditions. Uncommon traumatic axis abnormalities are discussed with reference to incidence, causes, clinical findings, mechanism of injury, and roentgen characteristics.Picker Scholar, James Picker Foundation     

Reference Data of Vertebral Morphometry by X-ray Absorptiometry (MXA) in Argentine Women

Anterior, middle, and posterior heights and A/P and M/P ratios were determined from T5 to L4 in 111 normal Caucasian Argentine women from 20 to 70 years of age using dual energy X-ray absorptiometry (DXA) densitometry (Expert XL). Scanning time was less than 1 minute and the semiautomatic analysis requires ∼5 minutes. The precision error for the measurements ranged from 2.2% to 4.6%. The absolute precision error for heights was 0.6 mm. The vertebral bodies tended to be significantly larger in younger women than older women, especially for anterior and middle heights and the A/P and M/P ratios of the mid-thoracic vertebrae (T6–T10). There were no significant differences between pre- and postmenopausal women in the lumbar vertebral heights. It does not appear that this was a cohort effect because stature was identical in both age groups, and there was no age difference in posterior height. The Expert-XL software normalized the vertebral height based on the average height of the L2-L4 segment in order to minimize the influence of interindividual variation of body size. The average Z-scores for vertebral heights and ratios provided by the software were close to zero indicating that the normalization procedure appropriately corrected for smaller stature in Argentine women. Consequently, the reference values for morphometry X-ray absorptiometry (MXA) were appropriate for our population. In summary, we found that (1) in ``normal' women the anterior heights of the thoracic vertebrae (and therefore the A/P ratio) were higher in premenopausal than in postmenopausal women; and (2) the normalization approach corrected for differences of vertebral height and allowed utilization of the manufacturers software in our population. Received: 28 June 1999 / Accepted: 2 November 1999     

The relationship between phalangeal bone density and vertebral deformities

Radiographic absorptiometry (RA) of the phalanges is a convenient and reliable technique for measuring bone mineral density (BMD). It needs only a radiograph of the hand, which can be sent for evaluation to a central facility, whereas other techniques require specialized equipment. We assessed the relationship between RA measurements and the presence of vertebral deformities in a population-based cohort of postmenopausal women, and to compare the results with simultaneously obtained BMD of the hip by dual-energy X-ray absorptiometry (DXA). A total of 389 women aged 55–84 (mean age 67.2 years, SD 8.7) were randomly selected from a large general practice. RA, DXA of the hip, and vertebral deformities in the lateral spine X-rays by vertebral morphometry were assessed. Thirty-eight women (9.8%) had severe (grade II) vertebral deformities, and their BMD at the phalanges and femoral neck was significantly lower than that of women without severe vertebral deformities. Odds ratios for the presence of severe vertebral deformities of 1.5 (95% CI: 1.1–2.1) for RA and 1.3 (95% CI: 0.9–1.9) for DXA, together with similar receiver operating characteristics curves, were found using age-adjusted logistic regression. Phalangeal BMD is related to vertebral deformities at least as closely as BMD of the femoral neck BMD. RA may therefore help to evaluate fracture risk, especially if no DXA equipment is available. Received: 21 July 1998 / Accepted: 1 July 1999     

脊椎血管瘤手术后复发放射治疗疗效观察(附6例报告)

目的 探讨脊椎血管瘤手术后复发放射治疗疗效和适宜剂量。方法 1968—1992年间共收治手术后复发的有症状的脊椎血管瘤6例，中位年龄28岁。病灶在胸椎5例，腰椎1例。4例有病灶局部疼痛合并不完全性截瘫，2例为局部疼痛合并下肢麻木无力。采用^60Co和8MV—X线照射治疗，总剂量范围30-60Gy，平均40Gy。结果 所有接受放疗的患均获得良好的远期效果，4例不完全截瘫患中3例基本恢复，1例完全恢复，另外2例原有的下肢麻木症状消失，但影像学检查均无明显改变。结论 放射治疗对手术后复发的脊椎血管瘤是安全有效的，剂量以36—40Gy为宜。但放射治疗起效比较慢，且影像学改变不明显，所以应以远期症状改善率作为评价放射治疗效果的标准。     

33例椎-基底动脉瘤的临床观察

目的：探讨椎－基底动脉瘤治疗方法与预后关系。材料与方法：报告３３例椎－基底动脉瘤。动脉瘤破裂致ＳＡＨ１８例，动脉瘤直径从５ｍｍ到４５ｍｍ。其中９例行保守治疗。直接手术治疗中，９例夹闭术，２例瘤壁加固术。１３例行血管内栓塞治疗。结果：９例保守治疗中３例因再次出血死亡。１１例直接手术均痊愈。１３例血管内栓塞治疗后１～３个月后复查造影，闭塞率＞８０％者１２例。结论：椎－基底动脉瘤积极手术治疗可降低死亡率，依动脉瘤部位与大小采用不同手术入路至关重要，血管内栓塞治疗适于直接手术难以达到者，疗效肯定。     

椎板开窗手术治疗腰椎间盘突出症108例分析

目的　探讨椎板开窗法摘除髓核治疗腰椎间盘突出症的可行性及其手术操作要点。方法　对10 8例腰椎间盘突出症行椎板开窗法摘除髓核术并对疗效作出评价。结果　采用椎板开窗法摘除髓核术治疗腰椎间盘突出症 ,疗效优良达 97%。结论　本术式具有操作简便、损伤小、出血少、病人恢复快等优点 ,值得临床推广。     

联合激光与传统药物治疗原发性闭角型青光眼急性发作期的临床研究

目的评价激光周边虹膜成形术联合激光瞳孔成形术与传统降眼压药物治疗原发性闭角型青光眼急性发作的有效性和安全性。 方法收集2014年1月至2015年7月于邯郸市眼科医院(邯郸市第三医院)就诊的62例(68只眼)确诊为原发性闭角型青光眼首次急性发作并未做降眼压治疗患者的病例资料。其中,男性15例(17只眼),女性47例(51只眼),平均年龄(67.5±8.5)岁,所有患者眼压升高≥40 mmHg(1 mmHg＝0.133 kPa)。将入选患者采用数字表法随机分为激光组和药物组。激光组给予激光周边虹膜成形术联合激光瞳孔成形术治疗,药物组给予传统降眼压药物治疗。采用TA03型Icare眼压计测量治疗前、治疗后1 h和2 h的眼压,记录两组角膜及前房情况。以治疗后2 h眼压降至30 mmHg及以下为抢救成功,反之则为治疗失败。激光组和药物组年龄、就诊时眼压和发作时间等资料的描述采用均数±标准差表示,组间比较使用独立样本t检验;两组治疗成功率的描述采用眼数和百分比,比较采用χ²检验;两组治疗前、治疗后1 h和2 h眼压的比较采用两因素重复测量方差分析。 结果治疗后1 h激光组14只眼抢救成功,成功率为41.2%;药物组15只眼抢救成功,成功率为44.2%。治疗后2 h激光组18只眼抢救成功,成功率为52.9%;药物组20只眼抢救成功,成功率为58.2%。治疗后1 h与2 h两组间成功率无统计学意义( χ²＝0.06,0.24;P>0.05)。激光组治疗前视力为光感至0.4,治疗后1 h视力为眼前手动至0.6,治疗后2 h视力为眼前手动至0.6。药物组治疗前视力为光感至0.4,治疗后1 h视力为光感至0.8,治疗后2 h视力为光感至0.8。两组主要并发症为前房内炎症反应和角膜内皮皱褶,无眼内感染和脉络膜下暴发性出血等严重并发症。激光组治疗前、治疗后1 h和2 h平均眼压分别为(56.9±8.7)mmHg、(37.9±16.2)mmHg和(32.9±16.4)mmHg,治疗后眼压下降,与治疗前的比较差异有统计学意义(t＝6.02,7.76;P<0.05)。药物组治疗前、治疗后1 h和2 h平均眼压分别为(55.8±9.5)mmHg、(37.6±17.7)mmHg和(30.6±18.2)mmHg,治疗后眼压下降,与治疗前的比较差异有统计学意义(t＝5.28,7.16;P<0.05)。但两组各时间点的眼压比较均无统计学意义(t＝0.89,0.58,0.85;P>0.05)。 结论激光周边虹膜成形术联合激光瞳孔成形术和传统的降眼压药物治疗均能快速降低原发性闭角型青光眼急性发作期的眼压,但激光治疗安全、有效,可避免药物治疗给机体带来的副作用,是治疗原发性闭角型青光眼急性发作期的重要辅助措施。