Direct ultrasonographic measurement of femoral anteversion in newborns

A direct method of ultrasonographic measurement of the anteversion angle of the femoral neck is presented. Normal values based on measurements in 30 random newborns with vertex presentation correspond well with figures from previous autopsy series. The femoral anteversion in breech presentation was found to be on average 10° greater than in vertex presentation (p<0.0001).     

《中华消化杂志》11年刊出论著回顾性分析

本文对《中华消化杂志》１１年刊出论著及论著摘要进行了回顾性分析。病例分析论著从８２年的４１．０％减少至９２年的６．３％（Ｐ＜０．０１）。实验观察论著从８２年的３５．９％增加到９１年的６４．１％（Ｐ＜０．０５）。治疗性论著中无对照比例由８２年的４／５降至９２年的０／５（Ｐ＜０．０５），但随机对照的论著不多。调查研究性论著８２年无一篇，９２年已达７篇（Ｐ＜０．０５）。以上各项与两种外刊相比已无明显差别，但论著的科研设计内容，仍有待提高。此外用Ｓａｃｋｅｔｔ的标准对诊断性论著进行了初步评价。     

Experimental studies on fracture-healing

The bending of the tibiae of dogs and rabbitsin vivo was studied. A new physical method (margin of errors less than 1%) which gives readily reproducible values of bone stability is reported. The results of bending stiffness, measuredin vivo andin vitro, were nearly identical only if the extremities were slim. If thick, soft parts in the measuring area were present, different loading values followed the same bending. A formula to correct the influence of the soft parts (skin, muscles and tendons) was proposed. The true bending stiffness was determined with the aid of thein vivo values without having to measure the exposed bone afterwards. Comparisons of measurements showed that the values found with the formula reflected the true bending stiffness in a range of errors between 0.3 and 10.5%. A load of 4700±710 g gave a true bending stiffness of 0.1 mm and of a bone area of 1.0 cm².

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Zusammenfassung Die Beugung von Hunde- und Kaninchen-Tibias wurdein vivo untersucht. Eine neue einfache physikalische Methode (Fehlergrenze weniger als 1%), welche reproduzierbare Werte der Knochenstabilität vermittelt, wurde dabei angewandt. Die Resultate der Beugungs-Steifheit, welchein vivo undin vitro gemessen wurde, zeigten nur dann fast identische Werte, wenn die Extremitäten dünn waren. Sobald dicke, weiche Stellen im gemessenen Bereich vorhanden waren, erfolgten bei der gleichen Beugung unterschiedliche Belastungswerte. Es wird eine Formel vorgeschlagen, die den Einfluß der weichen Stellen (Haut, Muskeln und Sehnen) korrigieren soll. Die richtige Beugungs-Steifheit wurde mit Hilfe derin vivo-Werte bestimmt, ohne daß nachher der freigelegte Knochen gemessen werden mußte. Vergleichende Messungen zeigten, daß die mit dieser Formel gefundenen Werte die richtige Beugungs-Steifheit mit einer Fehlergrenze zwischen 0,3 und 10,5% wiedergaben. Eine Belastung von 4700±710 g ergab die korrekte Beugungs-Steifheit von 0,1 mm in einem Knochenbereich von 1,0 cm².

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Résumé La courbure des tibias de chiens et de lapins a été étudiéein vivo. Une nouvelle méthode physique (avec une marge d'erreur inférieure à 1%) donne des valeurs de stabilité osseuse aisément reproductibles. Les résultats de rigidité de courbure, mesuréein vivo etin vitro, sont trés voisins lorsque les extrémités sont minces. Lorsqu'elles sont épaisses, des tissus mous sont présents dans la région à tester et différentes valeers de charges suivent la même courbure. Une formule pour compenser l'effet des tissus mous (peau, muscles et tendons) est proposée. La rigidité vraie de courbure est déterminée à l'aide des valeursin vivo sans devoir mesurer par la suite l'os mis à nu. La comparaison des mesures montrent que les valeurs obtenues à l'aide de la formule traduisent la rigidité vraie de courbure avec une marge d'erreurs de 0,3 à 10,5%. Une charge de 4700±719 g donne une rigidité vraie de courbure de 0,1 mm, d'une surface osseuse de 1,0 cm².

     

Statistical methods for assessing agreement between double readings of clinical measurements

Statistical analysis of data is crucial in cephalometric investigations. There are certainly excellent examples of good statistical practice in the field, but some articles published worldwide have carried out inappropriate analyses.

Objective

The purpose of this study was to show that when the double records of each patient are traced on the same occasion, a control chart for differences between readings needs to be drawn, and limits of agreement and coefficients of repeatability must be calculated.

Material and methods

Data from a well-known paper in Orthodontics were used for showing common statistical practices in cephalometric investigations and for proposing a new technique of analysis.

Results

A scatter plot of the two radiograph readings and the two model readings with the respective regression lines are shown. Also, a control chart for the mean of the differences between radiograph readings was obtained and a coefficient of repeatability was calculated.

Conclusions

A standard error assuming that mean differences are zero, which is referred to in Orthodontics and Facial Orthopedics as the Dahlberg error, can be calculated only for estimating precision if accuracy is already proven. When double readings are collected, limits of agreement and coefficients of repeatability must be calculated. A graph with differences of readings should be presented and outliers discussed.     

危重病人24h动态胃内pH和胆汁反流监测的研究

目的 探讨危重病人胃内pH值变化及是否伴有胆汁反流,为应激状态下急性胃黏膜病变(AGML)的防治提供理论依据探讨.方法 对收治重症监护病房(ICU)的30危重病人(观察组)利用便携式pH监测仪和Bilitec 2000胆汁监测仪进行24h动态胃内pH值及胆汁反流监测,并观察抑酸剂对胃内pH值的影响.对照组为20例有上腹症状,胃镜诊断为胆汁反流性胃炎的的门诊病人.结果 观察组好转20例、死亡8例,放弃抢救2例.发生AGML并出血2例.观察组胃内pH＞4者17例、部分时间pH＞4者13例,对照组所有病人仅部分时间pH＞4,两组比较P＜0.001.观察组pH＜4时间(min)(151.4±382.6)明显少于对照组(1086.3±295.0)(P＜0.001),观察组用抑酸剂的病人胃内pH值＜4时间(11.6±28.4)明显少于未用抑酸剂者(291.10±51.05).观察组胃内胆红素吸光值(abs)＞0.14的时间(min)(231.3±319.3)与对照组(341.9±273.9)差异无显著性(P=0.21).结论 危重病人胃酸分泌受抑制,胃内pH值增高,部分同时伴有胆汁反流.     

Electromagnetic head-and-neck hyperthermia applicator: experimental phantom verification and FDTD model

PURPOSE: To experimentally verify the feasibility of focused heating in the neck region by an array of two rings of six electromagnetic antennas. We also measured the dynamic specific absorption rate (SAR) steering possibilities of this setup and compared these SAR patterns to simulations. METHODS AND MATERIALS: Using a specially constructed laboratory prototype head-and-neck applicator, including a neck-mimicking cylindrical muscle phantom, we performed SAR measurements by electric field, Schottky-diode sheet measurements and, using the power-pulse technique, by fiberoptic thermometry and infrared thermography. Using phase steering, we also steered the SAR distribution in radial and axial directions. All measured distributions were compared with the predictions by a finite-difference time-domain-based electromagnetic simulator. RESULTS: A central 50% iso-SAR focus of 35 +/- 3 mm in diameter and about 100 +/- 15 mm in length was obtained for all investigated settings. Furthermore, this SAR focus could be steered toward the desired location in the radial and axial directions with an accuracy of approximately 5 mm. The SAR distributions as measured by all three experimental methods were well predicted by the simulations. CONCLUSION: The results of our study have shown that focused heating in the neck is feasible and that this focus can be effectively steered in the radial and axial directions. For quality assurance measurements, we believe that the Schottky-diode sheet provides the best compromise among effort, speed, and accuracy, although a more specific and improved design is warranted.     

Detection of histamine-induced capillary protein leakage and hypovolaemia by determination of indocyanine green and glucose dilution method in dogs

Objective: The plasma volume of histamine-induced protein capillary leakage may be overestimated when this is determined using the indocyanine green (ICG) dilution method (Vd-ICG), since this dye binds to plasma proteins. The initial distribution volume of glucose (IDVG) has been shown to indicate the central extracellular fluid volume including plasma. Accordingly, the overestimation would be detected by a higher Vd-ICG/IDVG ratio. Our study was intended to examine whether the simultaneous measurement of these two variables can evaluate histamine-induced protein leakage and associated hypovolaemia. Design: Prospective animal study. Setting: Institutional animal research laboratory. Subjects: Twenty-four anaesthetized and ventilated mongrel dogs. Interventions: Anaesthetized animals were mechanically ventilated and received infusions of normal saline (n = 8), histamine 50 μg/kg per h (n = 8), or histamine 100 μg/kg per h. The Vd-ICG and IDVG were calculated using a one-compartment model by simultaneous administration of ICG 0.5 mg/kg, and glucose 100 mg/kg followed by serial arterial blood sampling. Measurements and results: In both histamine groups, a significant elevation of haematocrit and a decrease of plasma albumin concentration were found (p < 0.05). Although the IDVG decreased following histamine administration (p < 0.05), the Vd-ICG remained unchanged. The Vd-ICG/IDVG ratio increased in a dose-dependent manner after histamine administration (p < 0.05), but remained unchanged following normal saline administration. Conclusion: The results suggest that the Vd-ICG/IDVG ratio and the IDVG are useful in evaluating the magnitude of the leakage and hypovolaemia. Received: 1 July 1998 Accepted: 29 December 1998 Final revision received: 8 December 1998     

Assessment of gestational age using cerebellar measurements at cranial ultrasound: What is the best approach?

Background and aims

Clinical assessment of gestational age (GA) in preterm infants can be challenging. Several ultrasound approaches for estimating GA using cerebellar measurements are reported, claiming to be simpler and more accurate than clinical assessment, but they are not widely used. We aimed to compare the accuracy of four previously described measurements and compare their use in preterm infants.

Methods

We studied infants < 32 weeks of GA defined by in-vitro fertilization date or early fetal ultrasound, excluding infants with neurological problems. Vermis anterior–posterior diameter (VAPD), vermis height (VH), and transverse cerebellar diameter via anterior (TCDa) and mastoid fontanelles (TCDm) were measured.Estimated PMA was calculated using published equations, and compared to known PMA using intraclass correlation coefficient (ICC). Intra and inter-observer reliability were determined.

Results

We studied 80 infants (mean GA 28.5 weeks [range 24–32], mean post-natal age 5.7 days). ICC was 0.761 (VAPD), 0.632 (VH), 0.115 (TCDa) and 0.825 (TCDm). The TCDm equation gave the best estimate of GA (mean estimate − 2 days; 95% CI ± 13.8 days). TCDa and TCDm absolute measurements were similar for each infant. Accuracy for estimating GA was similar for appropriately grown and small-for-gestation infants. Inter and intra-observer reliability was very good for all measurements.

Conclusions

Three previously described equations for estimating GA from cerebellar measurements gave good estimates of GA in preterms. The equation described for TCDm gave the narrowest 95% CI. We recommend the TCDm equation for the estimation of GA in VLBW infants but the TCD measurement can be made via either the anterior or mastoid fontanelle.     

Severe retinopathy in type 1 diabetic patients is not related to the level of plasma homocysteine

The new diagnostic criteria for type 2 diabetes from the American Diabetes Association (ADA) and World Health Organization (WHO) recommend measurements on plasma and a lowering of the glucose threshold for diabetes by 0.8mmol/L. This narrows the distance between the upper end of the reference limit and the discriminatory level to a degree where analytical quality becomes critical. The quality demands for the preanalytical and analytical phase and their consequences on diagnostic performance have to be established in the new technical system, measuring in plasma rather than in capillary whole blood. Because of the instability of glucosein blood samples it is necessary to clarify the influence of different preanalytical and analytical factors on the number of false-positive and false-negative classifications. Thus the aim of the present study was to find optimal conditions for sampling, additives, storage, transport and analysis of plasma glucose combining feasibility with an analytical bias close to zero and a within-imprecision around 1%. We have documented the analytical performance of the method itself and its traceability to an international standard. The preanalytical conditions, such as influence of antiglycolytic agent NaF, conditions for plasma separation, storage temperature and storage time before and after plasma separation were investigated. In conclusion, we recommend that blood should be drawn in tubes containing heparin and NaF and kept on ice water for not more than 1h until centrifugation at minimum 1000 g for 10min. The plasma is then stable for at least 48h at room temperature.