经皮椎体注入骨水泥治疗老年脊椎骨质疏松压缩性骨折

目的:观察经皮椎体内注入骨水泥(聚甲基丙烯酸甲酯)治疗脊椎骨质疏松压缩性骨折的疗效。方法:自2005-06/2006-06吉林大学中日联谊医院骨科及大庆龙南医院骨科对35例40个椎体的骨质疏松压缩性骨折患者使用经皮椎体内注射骨水泥,行椎体成形术。成形材料:美国KYPHON公司生产的骨水泥,生产准许号:(GB/T19001-2000和YY/T0287-1996)。结果:35例患者均参加随访6个月。术后均未出现骨水泥外漏、脊髓或马尾神经损伤等并发症。35例患者中5例出现穿刺部位局部疼痛,服用镇痛药物后均缓解。疼痛完全消失25例,占71.4%;明显缓解8例,占22.6%;轻度缓解2例,占6.0%;无缓解0例。15例患者在术后72h内均能下床活动。术后未再发生压缩性骨折及疼痛。结论:经皮椎体注入骨水泥可以有效改善椎体骨质疏松压缩性骨折患者疼痛症状,随访6个月未出现充填剂不良性宿主反应,临床疗效较好。     

Volume acceleration as an index of neuromuscular output

At the transition from expiration to inspiration, when flow and volume changes are small, changes in the respiratory system driving pressure could determine the degree of volume acceleration (AI), which, in turn, could reflect the degree of respiratory center output. To test this hypothesis, we calculated AI occurring in each respiratory cycle at the transition from expiration to inspiration during CO2 rebreathing in 4 healthy supine subjects. To minimize the flow and volume change over the measurement interval, we measured AI just prior to inspiration within the limits of an expiratory flow of 0.2 L . sec -1 to zero flow using digital differentiation. We also measured mouth pressure 100 msec after the onset of inspiration (P0.1) during intermittent transient inspiratory airway occlusions. During CO2 rebreathing AI increased significantly with both increasing PCO2 and P0.1. We also compared pairs of rebreathing studies, performed without and with an alinear (16 cm H2O . L -1 . sec -1) inspiratory resistor (IR), repeated twice in the 4 subjects. IR markedly decreased delta VE/delta PCO2 and the slope of the increase in mean inspiratory flow rate with PCO2 (delta VT/TI/delta PCO2) but did not significantly alter either delta AI/delta PCO2 or the increase in P0.1 with PCO2 (delta P0.1/delta PCO2). However, the effects of IR on AI and P0.1 differed between the early and late phases of each rebreathing run; early in the rebreathing runs (PCO2 = 55 Torr) IR increased both AI and P0.1 by a similar amount, but near the end of rebreathing (PCO2 = 60 Torr) IR increased P0.1 but not AI. Our results are consistent with the possibility that AI reflects neuromuscular output under the conditions of the study. Hence this approach justifies further evaluation to determine its general applicability.     

Evaluation of a computerised test for the assessment of peripheral vascular disease

This paper reports a study carried out in 200 patients to assess the effectiveness of a clinical vascular laboratory in the routine assessment of peripheral vascular disease (PVD) of the lower limb. Laboratory assessments involved a computer based hierarchical testing system incorporating pedal pressure indices, maximum walking distances and principal component analysis of the common femoral artery blood velocity waveform. The study fell into two parts. In the first, the laboratory assessments of 100 patients referred six years ago were compared retrospectively with their eventual clinical outcome. In this comparison, the laboratory provided a "diagnosis" which was 79% correct. In the second, a double blind prospective study was carried out in 100 patients to compare the vascular laboratory "diagnosis" with the diagnosis and prognosis of a skilled clinician, the outcome being compared one year after the initial assessment. In this study the laboratory proved to be correct in 78% of cases, the clinician in 70%. With a slightly modified computer protocol for the non vascular diagnosis, the computer would have been correct in 85% of cases. This test provides a quantitative and objective assessment of PVD which can assist in the patient's clinical diagnosis and management.     

The challenges of success: adolescents with perinatal HIV infection

The great success in the prevention and treatment of pediatric HIV in high resource countries, and now in low resource countries, has changed the face of the HIV epidemic in children from one of near certain mortality to that of a chronic disease. However, these successes pose new challenges as perinatally HIV‐infected youth survive into adulthood. Increased survival of HIV‐infected children is associated with challenges in maintaining adherence to what is likely life‐long therapy, and in selecting successive antiretroviral drug regimens, given the limited availability of pediatric formulations, limitations in pharmacokinetic and safety data of drugs in children, and the development of extensive drug resistance in multi‐drug‐experienced children. Pediatric HIV care must now focus on morbidity related to long‐term HIV infection and its treatment. Survival into adulthood of perinatally HIV‐infected youth in high resource countries provides important lessons about how the epidemic will change with increasing access to antiretroviral therapy for children in low resource countries. This series of papers will focus on issues related to management of perinatally infected youth and young adults.     

Renal manifestations in children co-infected with HIV and disseminated tuberculosis

Many children in Cape Town are co-infected with human immunodeficiency virus (HIV) and tuberculosis (TB). Granulomatous TB interstitial nephritis is a recognized entity. Our objective was to establish if TB plays a role in renal disease in HIV-infected children. We identified children co-infected with TB and HIV from our database and reviewed their biopsies and clinical notes. Since 2002, 12 renal biopsies or postmortem examinations were performed on HIV-infected children at our institution. The clinical scenario and renal biopsies in four cases (median age 73 months, range 24–108 months) were consistent with TB involvement. The mean CD4 count and percentage of these four patients were 508 cells/μl and 23%, respectively. All four patients presented with culture-proven disseminated TB (not yet on treatment) and had nephrotic range proteinuria and hypoalbuminemia. Three of these patients had renal impairment. The prominent features of the renal biopsies were a severe interstitial inflammatory infiltrate and mild to moderate mesangial proliferation. An interstitial granuloma was seen in one patient. With treatment for the TB, the proteinuria resolved and renal function improved in all four patients. Based on these results, we conclude that TB contributes to proteinuric renal disease in HIV-infected children and that the renal disease improves following TB treatment.     

Tetrahydrobiopterin loading test in hyperphenylalaninemia.

Some cases of primary hyperphenylalaninemia are not caused by the lack of phenylalanine hydroxylase, but by the lack of its cofactor tetrahydrobiopterin. These patients are not clinically responsive to a phenylalanine-restricted diet, but need specific substitution therapy. Thus, it became necessary to examine all newborns screened as positive with the Guthrie test for tetrahydrobiopterin deficiency. Methods based on urinary pterin or on specific enzyme activity measurements are limited in their availability, and the simplest method, based on the lowering of serum phenylalanine after loading with cofactor, was discouraged by the finding that some dihydropteridine reductase-deficient patients were unresponsive. The preliminary observation that this limitation could be overcome by increasing the dose of the administered cofactor prompted us to reevaluate the potential of the tetrahydrobiopterin loading test in hyperphenylalaninemia. Fifteen patients, eight with ultimate diagnosis of phenylketonuria, three with 6-pyruvoyl tetrahydropterin synthase-, and four with dihydropteridine reductase-deficiency, have been examined by administering synthetic tetrahydrobiopterin both orally, at doses of 7.5 and 20 mg/kg, and i.v., at a dose of 2 mg/kg. All the tetrahydrobiopterin-deficient patients, unlike those with phenylketonuria, responded to the oral dose of 20 mg/kg cofactor by lowering their serum phenylalanine concentration markedly below baseline to an extent easily detectable by Guthrie cards. This method allows for a simple screening method when enzyme or pterin studies are not available.     

The hemodynamic effects of intubation during nitroglycerin infusion in severe preeclampsia

The effectiveness of intravenous nitroglycerin infusion in lowering maternal blood pressure and in blunting the hemodynamic responses to endotracheal intubation was evaluated in six primigravid women with severe preeclampsia. Monitoring consisted of continuous electrocardiogram monitoring, arterial cannulation, and flow-directed pulmonary arterial catheterization in each patient. All patients underwent oxytocin induction of labor and crystalloid and/or colloid expansion to produce a pulmonary capillary wedge pressure of 10 to 15 mm Hg and a colloid osmotic pressure of greater than 17 mm Hg. Intravenous nitroglycerin was administered before induction of general anesthesia. The hemodynamic effects associated with endotracheal intubation revealed a change in the heart rate from 104 +/- 10 to 133 +/- 17 beats/min, an increase in mean arterial pressure from 134 +/- 12 to 164 +/- 32 mm Hg, and an increase in systemic vascular resistance from 1262 +/- 342 to 1351 +/- 259 dynes-sec-cm-5 that was accompanied by a small change in the cardiac index from 4.5 +/- 1.2 to 4.5 +/- 0.9 L.min-1.m-2.     

Update of the Cincinnati experience in pediatric laryngotracheal reconstruction

Surgical endeavors in the field of laryngotracheal reconstruction in children have received much interest in the past 15 years. A unique experience with laryngotracheal reconstruction in 203 children is reviewed. The majority (194) of the cases were classified as acquired; only nine were classified as congenital. Excluded from the study were those cases of stenoses managed endoscopically, all resections and end-to-end anastomoses, all anterior cricoid split procedures, and all cases of anterior glottic stenosis repaired by a laryngeal keel. The degree of stenosis was graded into four categories. Five different methods of laryngotracheal reconstruction were used depending on the pathologic lesion in the larynx and trachea. Of the 203 children, 186 (92%) were decannulated. The results support the use of laryngotracheal reconstruction in children with grades 2, 3, and 4 laryngeal stenosis.