用Sauvegrain法测定青春期骨龄准确性的研究

背景：Sauvegrain方法是通过分析肘部X线片来评估骨龄，常用于青春期生长发育最为迅速的两年间的骨龄测定。本文旨在研究该方法的准确性以及在小儿骨科中的应用价值。 方法：Sauvegrmn法主要评估肘部的4个解剖标志点：外髁、肱骨滑车、尺骨鹰嘴突以及桡骨近端骨骺。它是一个27分制的评分系统。对上述结构所得的评分进行合计而得出一个总分，然后使用标准图表确定骨龄。让三位观察者分别利用该方法进行骨龄评估。三位观察者通过分析60个男孩和60个女孩样本左肘部的前后位和侧位X线片来测定骨龄，并将该结果与通过分析左手和腕部后前位X线片的Greulich和Pyle图谱而得出的骨龄结果进行比较。间隔4周后每个观察者再测定骨龄一次。 结果：通过分析肘部X线片的方法测定骨龄更为精确，因为采用该方法测定骨龄可以精确到半岁。根据观察者的评定，Sauvegrain法显示出很好的观察者之间的相关性（r=0．93）和可重复性（r=0．96）。Sauvegrain法与Greulich和Pyle图谱之间有很好的相关性（r=0．85）。然而，一些肘部生长中心显示出一种中间的发育形态，这种形态学不适合Sauvegrain法的评分。这就导致了数据分析时出现误差。我们建议对于这些样本设定中间评分，并且通过修改原始图表而使评分更为精确。 结论：改良的Sauvegrain法简单、可靠而且可重复性高，它补充了Greulich和Pyle图谱的不足。在临床实践中，骨骼成熟度可以通过骨龄、年生长率以及第二性征而得以很准确的评估。因此，当青春期需要进行骨骺或脊柱关节融合术时，这种方法对于确定手术时间具有重要意义。 可信水平：诊断性研究，Ⅱ级，进一步可信度参见作者介绍。     

Determination of the ratios of the aromatic amino acid residues by first- or second-derivative UV spectrometry for a simple characterization of peptides

A method for the simultaneous determination of the ratios of the three aromatic amino-acid residues in peptides was set up in acidic conditions. Binary and ternary mixtures of these amino acids were prepared, and first- and second-derivative spectra then calculated from their 0.1 nm resolution spectra between 240 and 320 nm. Certain spectral bands were chosen to differentiate tyrosine from tryptophan on the first-derivative spectra, and phenylalanine from tyrosine and tryptophan on the second-derivative spectra. Variation of the amplitude of the chosen bands was shown to be a linear function of the ratio of the aromatic amino acids in the mixture. This technique was validated with peptides whose sequence was known. The difference between theoretical and experimentally determined ratios was lower than 10%. Since the results are obtained as ratios, neither the concentration nor the nature of the peptide has to be known. The feasibility of application using a photodiode array detector with high resolution in reversed-phase high-performance liquid chromatography is discussed. © Munksgaard 1995.     

Dramatic improvement of severe dilated cardiomyopathy in an acromegalic patient after treatment with octreotide and trans-sphenoidal surgery

Severe congestive heart failure developed in an acromegalicpatient, and was successfully treated with octreotide followedby trans-sphenoidal surgery. Clinical, hormonal echocardiographicand haemodynamic findings as well as histological heart examinationbefore and after treatment revealed tliat over-production ofgrowth hormone may induce the myocardial cell degeneration responsiblefor mechanical heart dysfunction. In addition, this unique exampledemonstrates the reversibility of myocardial damage followingoctreotide and trans-sphenoidal surgery, leading to significantimprovement in cardiac function with minimal diastolic dysfunctionand moderate interstitial fibrosis.     

Lack of Amphetamine-Like Effects After Administration of Mefenorex in Normal Young Subjects

Mefenorex is an indirect sympathomimetic amine which acts as an anorectic drug and is used in combination with low diet to treat excess weight. The central nervous system (CNS) effects of mefenorex were assessed in a randomized, double-blind, three-way cross-over, placebo-controlled study involving nine healthy young male volunteers. They received either a single oral dose of mefenorex 80 mg (twice the recommended dose) or d-amphetamine sulfate 18 mg or a placebo at 1-week intervals. CNS pharmacodynamic measurements consisted of subjective evaluation (visual analogue scales and the Addiction Research Centre inventory (ARCI)), EEG, psychomotor performance and attention (tracking, simple and choice reaction times, tapping, continuous performance task, DSST, body sway) and memory (working memory and recall of a word list). d-Amphetamine produced a typical psychostimulant EEG profile (significant decrease in slow delta waves and increase in fast beta activities), significantly increased amphetamine, benzedrine and morphine–benzedrine scores of ARCI and significantly decreased body sway compared to placebo and mefenorex. A trend in favour of a stimulant effect occurred for all other parameters (particularly speed of reaction) and no changes of memory were noticed. In contrast, mefenorex did not produce an amphetamine-like EEG profile, neither significantly changed ARCI scores nor significantly modified psychomotor and memory performance compared to the placebo, although it induced a decrease in body sway. In conclusion, the present results indicate that a single oral dose of mefenorex, at twice the recommended daily dose, does not possess amphetamine-like subjective and EEG stimulant effects or sensations of well-being, often encountered with drugs of abuse liability potential, in a healthy young population.     

Inhomogeneity of Cellular Refractoriness in Human Atrium: Factor of Arrhythmia?

Spatial inhomogeneity of refractory periods, as measured during clinical electrophysiological studies, is a known predisposing factor of arrhythmia. We studied elective refractory periods (ERP) and action potential duration (ADP₉₀) on isolated human atrium. Twelve samples of right atrium obtained during cardiac surgery from patients with (n = 6) and without (n = 6) atrial fibrillation (AF) were studied by microelectrode technique. For each preparation, ERP were measured at basic cycle lengths (BCL) of 1,600, 1,200, 800, and 400 msec in five different cells located around (0.8 mm) the stimulating electrode. Dispersion of ERP was significantly greater in the AF group (96.7 ± 9 versus 70.9 ± 9 msec, p = 0.01). In the non-AF group, we observed a positive linear correlation between (1) ERP and BCL (f = 0.86) (2) ADP₉₀ and BCL (= 0.93). On the contrary, in the AF group this correlation was absent between ERP and BCL (= 0.28), poor between ADP₉₀ and BCL (= 0.62). These results suggest that nonhomogeneous recovery of excitability (dispersion and poor adaptation) may be an important factor of arrhythmia. This inhomogeneity is present at the cellular level as well as in the entire heart.     

CENTRAL CARDIOVASCULAR EFFECTS OF DIHYDROPYRIDINES IN SPONTANEOUSLY HYPERTENSIVE RATS

Summary— Intracerebroventricular (i.c.v.) injections of dihydropyridine derivatives calcium channel agonist (BAY K8644) and antagonists (nifedipine, nicardipine, PN 200–110) induced opposite long-lasting changes in blood pressure (BP) in pentobarbital anesthetized spontaneously hypertensive rats (SMR). I.c.v. nifedipine (NIF), nicardipine (NIC), and PN 200–110 decreased mean blood pressure dose-dependently and stereoselec-tively, (+) NIC and (+) PN being 8 and 3 times more potent than their (-) isomers, respectively. The decrease in BP was due to a withdrawal of the sympathetic tone, since NIF- and NIC-induced falls in BP were suppressed after either hexamethonium (HXM), 6 OHDA or bilateral adrenalectomy. I.c.v. BAY K8644 increased BP dose-dependently. The i.c.v. BAY K8644-induced hypertensive effect was inhibited: a), by NIF and (+) PN but not by (-) PN, therefore probably occurring at central DHP sites; b), by HXM and reserpine, thus probably mediated by an increase in sympathetic tone; c), by i.c.v. methylatropine (MA) while i.v. MA and i.c.v. HXM had no inhibitory effect, thus probably involving central muscarinic sites. In SHR, NIC did not after the K+-evoked ACh release but suppressed the BAY K8644-induced increase in ACh release. In anesthetized normotensive control rats (WKY), neither i.c.v. NIF, NIC or BAY K8644 changed BP, nor did the latter after ACh release. Moreover, in conscious WKY, i.c.v. nicardipine increased BP and HR while, in conscious SHR it decreased BP without any change in HR. These data suggest that central DHP sites may be involved in the cholinergic transmission and may participate in genetic hypertension via sympathetic tone.     

Clinical Results of Low Energy Unipolar or Bipolar Activated Carbon Tip Leads

Biocompatibility of carbon makes it a good candidate for a pacing electrode. Moreover, activation of the electrode creates microporosity, which increases the surface area and reduces polarization losses. Chronic thresholds noninvasively measured on a large population of patients implanted with vitreous carbon electrodes of one manufacturer are significantly lower than those caused by polished platinum tip electrodes of the same manufacturer with similar electrode design.     

The Role of Catheter Ablation Techniques in the Treatment of Classic (Type 1) Atrial Flutter

Several attempts at circuit interruption of type 1 atrial flutter by means of surgical or catheter techniques have been published. We recently reported the results of a series of patients who underwent catheter fulguration of the low septal right atrium, with a mean follow-up of almost 3 years. True electrophysiological success was observed in 7/14 patients (50%). Clinical success, defined as absence of symptoms, was observed in 8/14 (57%) in this patient population. No serious complications were encountered, but the potential risks of DC shock, and the experience that we gained in right atrial mapping using this approach, led us to reconsider the role of atrial DC ablation in these patients. Additional studies assessing the meaning of fragmented electrograms, and identification of one for of severall slow conduction areas of the reentrant circuit are ongoing.     

What Can Be Expected of Balloon Aortic Valvuloplasty in Adults?

Introduced more than 15 years ago, balloon aortic valvuloplasty (BAV) has clearly delineated indications and limitations. Although, aortic valve replacement is undoubtedly the treatment of choice for healthy patients with aortic stenosis, BAV has been demonstrated as a valuable and safe palliative procedure for patients considered too risky or old for current day surgery. Between January 1991 and December 1999, 858 patients (mean age 76 ± 11 years, 479 [57%] women) underwent BAV at our center. Indications for BAV were contraindication to surgery in 16.2% of the patients, high risk in 40.4%, refusal of surgery in 10.7%, personal decision in 18.5%, and other in 14.2%. The mean gradient decreased from 65 ± 23 to 27 ± 12 mmHg and the valve area increased from 0.56 ± 0.19 cm² to 1.0 ± 0.38 cm². Eleven (1.1%) patients died during the procedure. The other severe complications were complete AV block in 18 (1.8%) patients, stroke in 8 (0.8%), tamponade in 6 (0.6%), and massive aortic insufficiency in 4 (0.4%). In conclusion, BAV does not replace valve replacement, even in the elderly. All those who can be operated on, should be. However, if surgical intervention is not considered reasonable, BAV offers good immediate results with an acceptable complication rate. Furthermore, previous published series have demonstrated that BAV is particularly indicated in specific subgroups, such as very old patients with high operative risk, end-stage heart failure, cardiogenic shock, or general anesthesia for noncardiac surgery.