Vascular reactivity, tissue levels, and binding sites for endothelin: a comparison in the spontaneously hypertensive and Wistar-Kyoto rats.

The role of endothelin (ET-1) in mediating the development of blood pressure was investigated in the spontaneously hypertensive (SHR) rat using the Wistar-Kyoto (WKY) rat as the normotensive control. The following were characterized in both rat strains: age-dependent changes in mean arterial blood pressure (MAP), tissue (blood, lung, heart, and kidney) levels of immunoreactive ET-1 like related peptides (ET-1RP), aortic ring responses to ET-1, and specific high-affinity tissue (lung, atrium, ventricle, aorta, and kidney) binding sites for 125I-labelled ET-1. Commencing at age 10 weeks through to 12 weeks, SHR rats but not WKY rats developed a significant increase in MAP (from 152 +/- 7 to 189 +/- 3 mmHg) (1 mmHg = 133.32 Pa). However, in both WKY and SHR rats immunoreactive levels of ET-1RP increased (100 and 80%, respectively) throughout the same measurement period. The potency of ET-1 to contract aortic rings from SHR rats was slightly but not significantly greater than that for aortic rings from WKY rats, although aortic rings from SHR rats contracted in the presence of 0.5 nM ET-1, while those from WKY rats did not. The levels of immunoreactive ET-1RP were significantly reduced (32%) in the kidney and unchanged in the heart and lung of SHR rats compared with WKY rats. Specific 125I-labelled ET-1 binding sites displayed an increase and a significant decrease (24%) of density in the atrium and ventricle, respectively, a significant increase (31%) of affinity in the lung, and were unchanged in the kidney and aorta of SHR rats compared with WKY rats following the development of hypertension. The lack of a correlation between circulating levels of immunoreactive ET-1RP and the development of hypertension coupled with a lack of significant differences in vascular reactivity suggest that ET-1 is not the sole mediator of hypertension in this animal model. However, the tissue-specific changes in immunoreactive ET-1RP and 125I-labelled ET-1 binding sites suggest that ET-1 may be a partial mediator of hypertension and is subject to compensatory changes in response to the increased total peripheral resistance in SHR rats.

Hip fractures and Parkinson's disease. A clinical review of 94 fractures treated surgically.

A series of 87 parkinsonian patients with 94 hip fractures were reviewed to reexamine the evidence for internal fixation versus hemiarthroplasty. Forty-seven subcapital Garden Type I and Type II fractures and transcervical fractures were treated by nailing, and 47 Garden Type III and Type IV fractures were treated by hemiarthroplasty. There were twice as many complications in the hemiarthroplasty group as in patients treated by nailing, including four wound infections and five dislocations, all with uniformly bad results. Patients treated by nailing regained greater ambulatory independence than those with a hemiarthroplasty. The parkinsonian patients with hip fractures treated by internal fixation had better results than those treated by hemiarthroplasty; hemiarthroplasty may be even contraindicated.

Pulmonary function test study and after spinal fusion in young idiopathic scoliosis.

A homogeneous population of 42 women with idiopathic scoliosis (mean age, 20.8 years and mean major thoracic curve of 58.2 degrees) had a complete pulmonary function test (PFT) at rest before, and a minimum of 3 years after, spinal fusion (mean, 7.7 years) to evaluate the effect of scoliosis and its surgical correction on PFT at rest. A multifactorial analysis showed that only the vital capacity (VC) was significantly lowered to 81% of predicted value (P less than 0.05). All of the other parameters of pulmonary volumes, flow, and gas exchanges, where corrected for the loss of lung volume, were within normal limits, showing pure restrictive changes in this population. Double-major curves were more severe, but no significant difference in PFTs were found with single thoracic curves. Curves over 50 degrees had significantly lower VC. The surgical correction of 40% is permanent and the functional improvement in postoperative vital capacity (VC) of 12% is significant (P less than 0.05). Other factors, such as the time between the two evaluations, the age of the patient, pelvic obliquity, trunk imbalance, and degree of kyphosis did not have any correlation with the observed changed on any of the PFT results. Therefore, early correction by spinal fusion in idiopathic scoliosis brings on some improvement of the vital capacity at rest and may prevent deterioration with progression of the curve.

Surgical treatment of post-traumatic kyphosis: a report of 16 cases.

Thoracic and lumbar spine fractures may lead to symptomatic progressive kyphosis for which surgery remains a controversial treatment. Sixteen patients with kyphosis were treated surgically at the Sacré-Coeur Hospital in Montreal between 1979 and 1985. The mean follow-up was 38 months. Initially, treatment of the fractures varied. On average the post-traumatic kyphosis was surgically corrected 34 months later. The corrective procedure consisted of staged anterior and posterior fusion with instrumentation (six patients), posterior fusion with instrumentation (five), staged anterior fusion, posterior osteotomy and fusion with instrumentation (four), posterior osteotomy and fusion with Harrington instrumentation (one). Anterior decompression was also performed in 5 of the 10 patients who had anterior fusion. There was no major perioperative complication. Pain was relieved in 13 patients and 9 of 11 had substantial neurologic improvement. Two patients had nonunion of posterior grafts, but these united after revision. The mean loss of correction in the early postoperative period was 3.5 degrees. The authors conclude that surgical treatment of post-traumatic symptomatic progressive kyphosis is effective and safe.

Unstable fractures of the thoracolumbar spine: a 10-year experience at Sacré-Coeur Hospital.

UNLABELLED: In a 10-year period, 108 unstable fractures involving the thoracolumbar junction (T11 to L2) were treated. This study evaluates the influence of the different treatments on the rate of complication, reduction of the fracture, and neurological recovery. METHODS: mechanism of injury, initial treatment and delay, neurologic deficit, operative findings, and duration of hospitalization were recorded. X-rays were reviewed for classification of fracture, measurement of deformity, and for instability scoring according to White and Panjabi's criteria. Seventy-seven patients were examined and nine more interviewed by telephone. RESULTS: a flexion-rotation injury occurred in 65% and a burst-fracture in 29%. A laminectomy was performed in 30 patients and Harrington instrumentation and fusion in 71 patients. Sixteen patients were treated conservatively. Fifty-five patients presented either a complete or partial neurological deficit. Seventy-five complications were noted and were more frequent in the laminectomy group. The instrumented group showed a clear tendency for earlier ambulation and discharge and pain level was found to be less. An increased residual deformity was found in patients treated by laminectomy, short fusion, and by nonsurgical modality. The neurologic recovery in the laminectomy and the nonlaminectomy group was not significantly different. Spinal realignment was better in the group where an instrumentation of five levels or more was performed and where posterior elements were not removed by laminectomy.