Nasal Symptoms Are Associated with School Performance in Adolescents

Children with asthma and allergy have higher school absence rates than others, but little is known about their school performance. In a study of 9538 adolescents, nasal symptoms severe enough to affect daily activity were associated with low-grade sum, particularly in adolescents using anti-allergy medication.     

The distribution of the maximum likelihood estimator in up-and-down experiments for quantal dose-response data.

Standard maximum likelihood logistic or probit regression has been used in biopharmaceutical practice for inference about tolerance threshold distributions in situations where subjects (patients) have been allocated doses according to an up-and-down design. For example, a steeper dose-response curve than expected was reported in one such study. This article demonstrates that the maximum likelihood estimator systematically and considerably exaggerates the regression parameter with moderately large sample sizes. Thus a probable explanation for finding a steeper curve than expected is the method used to analyze the experiment, that is, the bias in the maximum likelihood estimator. An additional consequence of this bias is that the mean/median/ED50 are estimated with a misleading precision. In particular, confidence intervals are much too narrow. As a conclusion, we warn against conventional logistic or probit regression in combination with up-and-down designs.     

Determination of urinary thymidine glycol using affinity chromatography, HPLC and post-column reaction detection: a biomarker of oxidative DNA damage upon kidney transplantation

Reactive oxygen species are generated during ischaemia-reperfusion of tissue. Oxidation of thymidine by hydroxyl radicals (HO) leads to the formation of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol). Thymidine glycol is excreted in urine and can be used as biomarker of oxidative DNA damage. Time dependent changes in urinary excretion rates of thymidine glycol were determined in six patients after kidney transplantation and in six healthy controls. A new analytical method was developed involving affinity chromatography and subsequent reverse-phase high-performance liquid chromatography (RP-HPLC) with a post-column chemical reaction detector and endpoint fluorescence detection. The detection limit of this fluorimetric assay was 1.6 ng thymidine glycol per ml urine, which corresponds to about half of the physiological excretion level in healthy control persons. After kidney transplantation the urinary excretion rate of thymidine glycol increased gradually reaching a maximum around 48 h. The excretion rate remained elevated until the end of the observation period of 10 days. Severe proteinuria with an excretion rate of up to 7.2 g of total protein per mmol creatinine was also observed immediately after transplantation and declined within the first 24 h of allograft function (0.35 ± 0.26 g/mmol creatinine). The protein excretion pattern, based on separation of urinary proteins on sodium dodecyl sulphate-polyacrylamide gel electrophorosis (SDS-PAGE), as well as excretion of individual biomarker proteins, indicated nonselective glomerular and tubular damage. The increased excretion of thymidine glycol after kidney transplantation may be explained by ischaemia-reperfusion induced oxidative DNA damage of the transplanted kidney. Received: 19 May 1999 / Accepted: 4 August 1999     

Haemodynamic interactions between the novel calcium sensitiser levosimendan and isosorbide-5-mononitrate in healthy subjects

OBJECTIVE: The new calcium sensitiser levosimendan also possesses vasodilatory effects due to potassium-channel opening. The aim of the present study was to assess the possible haemodynamic interactions between levosimendan and isosorbide-5-mononitrate in young healthy men. METHODS: The study was crossover, placebo controlled, double blind, randomised, and it comprised of four study days with one medication--levosimendan, isosorbide-5-mononitrate, levosimendan plus isosorbide-5-mononitrate or placebo--given on each. Levosimendan was administered i.v. as an initial bolus dose of 12 microg/kg over 10 min, followed by a continuous infusion of 0.2 microg/kg/min for a total time of 2 h. Isosorbide-5-mononitrate (20 mg) was given orally as a single dose. Leg blood flow and venous capacity (venous occlusion plethysmography), cardiac output (impedance cardiography), skin blood flow (laser-Doppler flowmetry), blood pressure and heart rate were recorded at baseline, and 20 min, 1 h, 2 h, 4 h and 6 h after the start of the infusion. An orthostatic test was performed at baseline and at 2 h 15 min. Twelve healthy, male subjects were included. Their mean age was 24 years (range 20-34 years). RESULTS: Levosimendan increased leg blood flow by 32%, and no additive effect of the combination of levosimendan and isosorbide-5-mononitrate was observed. The effects of levosimendan on heart rate and blood pressure were minimal and in close conformity with previous studies. In general, there were no additive effects of the combination compared with each drug alone at rest. The only additive effect was seen in the orthostatic response. Heart rate increased by 40 beats min(-1) with the combination (95% confidence interval compared with placebo 11-24 beats min(-1)), by 30 beats min(-1) with levosimendan (2-15 beats min(-1)), by 28 beats min(-1) with isosorbide-5-mononitrate (1-15 beats min(-1)), and by 22 beats min(-1) with placebo. Furthermore, three subjects were unable to stand upright for the stipulated time with the combination, and the orthostatic test had to be discontinued prematurely. There were no changes in the conduction intervals in the electrocardiogram on any of the treatments. The combination had no influence on the occurrence of headache compared with isosorbide-5-mononitrate alone. CONCLUSION: No major additive haemodynamic effects of the combination of levosimendan and isosorbide-5-mononitrate compared with each drug alone could be observed at rest. However, during an orthostatic test, the circulatory response was significantly potentiated with the combination, and three of the subjects were unable to stand upright for the stipulated time.     

Scintigraphic studies of uterine and placental growth and placental migration during pregnancy

Placental scintigraphy with 113mIn (Indium) combined with cervical marking with a shielded 57Co (Cobalt) radioactive source was used to study uterine and placental growth in human pregnancy and placental location and migration in a total of 176 patients. Uterine length measurements can be used for selecting growth retarded fetuses. There was an approximately constant ratio between placenta diameter and uterine length (0.68 +/- 0.03). When the placenta was located on the ventral uterine wall, low implantation occurred in 61%. The corresponding figure for low implantation when the placenta was located on the dorsal uterine wall was 30%. The difference was highly significant. Placental migration was studied in 20 patients. Significant migration occurred in 11 cases. The placental margin closest to the internal cervical os migrated outwards about 3 cm on average.     

Movement pattern of the Exeter femoral stem; a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years.

BACKGROUND: The design of the Exeter stem may facilitate distal migration, but radiostereometric analysis (RSA) studies have been limited to 2 years of follow-up. PATIENTS AND METHODS: We followed migration of the Exeter femoral stems in 22 primary hip arthroplasties for 5 years with RSA. RESULTS: All stems migrated distally and the median migration at 2 years was 1.34 mm, while at 5 years it was 1.77 mm. 7 stems migrated above accuracy between 3 and 5 years. (RSA) evaluation of the cement mantle could be performed in 14 cases, and in 5 slight migration was found. Most of the stems rotated towards retroversion and the median rotation at 2 years was 1.2 degrees, while at 5 years it was 1.6 degrees. We found 1 patient with impending clinical failure but no deviation in the RSA migration pattern, and 1 patient with unstable migration pattern but no clinical symptoms. INTERPRETATION: We found a greater distal migration of the Exeter stem for longer periods of time than seen with other types of cemented implants.     

双能量X线骨质密度测量仪监测小儿下肢骨延长骨矿物质的变化

目的　在儿童骨延长的患儿中 ,为了能够有效地控制骨延长的速率 ,达到骨延长的目的 ,采用双能量X线骨质密度测量仪 (dualenergyX Rayabsorptiometry ,DEXA)监测延长断端骨矿含量 (bonemineralcontent,BMC)的变化。方法　 30例患儿中有 5 0处下肢作了骨延长术 ,平均年龄10 .9岁 (5～ 17岁 ) ,引起短肢的病因不同。术后 7～ 10d开始行骨延长 ,每次延长 0 .2 5mm ,每天 4次。牵引延长期间每周扫描一次 ,拆除外固定器后每 2周扫描一次到术后 2年。DEXA扫描的分辨率是 1mm× 1mm ,扫描速度 30mm/s。比较不同延长时期中骨矿含量的变化。分析不同病因和不同外固定器之间骨矿含量变化的差别。结果　不同固定器之间骨矿含量的差别无著性意义。根据骨延长区BMC增加速率 ,将患儿分为快速组、一般组和慢速组。快速组每日BMC增加速率为 0 .3%～ 0 .6 % ,新骨生长快速 ;一般组每日BMC增加 0 .1%～ 0 .3% ,新骨中速生长 ;慢速组每日增加 <0 .1% ,新骨生成缓慢。骨矿化速率与原发病因相关。结论　DEXA能动态监测骨延长中新生骨的骨矿含量的变化 ,根据骨矿含量变化的程度 ,能够调整骨延长的速率 ,从而达到预期骨延长的目的。     

Experience with the Amplatz retrievable vena caval filter. Work in progress

The Amplatz retrievable vena caval filter was designed in an attempt to decrease complications associated with the placement of Mobin-Uddin or Kimray-Greenfield filters. The design allows percutaneous retrieval, thus expanding application of the filter to situations requiring temporary prophylaxis against pulmonary embolism. Filters have been placed in 16 patients, nine (56%) for prophylactic purposes. All filters were easily inserted percutaneously. Complications occurred in three patients; these included complete thrombosis of the inferior vena cava below the filter, misplacement of one filter into the pericaval retroperitoneal tissue, and development of thrombus cranial to the filter. With the current introduction system, the possibility of filter misplacement has been essentially eliminated. No patient experienced symptoms suggestive of pulmonary embolism after filter insertion. One filter retrieval has been performed, with no complications.     

Effect of medial arch-heel support in inserts on reducing ankle eversion: a biomechanics study

Background  

Excessive pronation (or eversion) at ankle joint in heel-toe running correlated with lower extremity overuse injuries. Orthotics and inserts are often prescribed to limit the pronation range to tackle the problem. Previous studies revealed that the effect is product-specific. This study investigated the effect of medial arch-heel support in inserts on reducing ankle eversion in standing, walking and running.