Neuroimaging in childhood arterial ischaemic stroke: evaluation of imaging modalities and aetiologies

Aim The aim of this study was to describe neuroimaging patterns associated with arterial ischaemic stroke (AIS) in childhood and to differentiate them according to stroke aetiology. Method Clinical and neuroimaging (acute and follow‐up) findings were analysed prospectively in 79 children (48 males, 31 females) aged 2 months to 15 years 8 months (median 5y 3mo) at the time of stroke by the Swiss Neuropaediatric Stroke Registry from 2000 to 2006. Results Stroke was confirmed in the acute period in 36 out of 41 children who underwent computed tomography, in 53 of 57 who underwent T2‐weighted magnetic resonance imaging (MRI) and in all 48 children who underwent diffusion‐weighted MRI. AIS occurred in the anterior cerebral artery (ACA) in 63 participants and in all cases was associated with lesions of the middle cerebral artery (MCA). The lesion was cortical–subcortical in 30 out of 63 children, cortical in 25 out of 63, and subcortical in 8 of 63 children. Among participants with AIS in the posterior circulation territory, the stroke was cortical–subcortical in 8 out of 16, cortical in 5 of 16, and thalamic in 3 out of 16 children. Interpretation AIS mainly involves the anterior circulation territory, with both the ACA and the MCA being affected. The classification of Ganesan is an appropriate population‐based classification for our Swiss cohort, but the neuroimaging pattern alone is insufficient to determine the aetiology of stroke in a paediatric population. The results show a poor correlation between lesion pattern and aetiology.     

Acute Success of Cryoablation of Left-Sided Accessory Pathways: A Single Institution Study

Objective: To compare the acute success and recurrence rate of cryoablation for left-sided accessory pathways (AP) with controls who underwent radiofrequency ablation (RFA) at the same institution.
Background: Catheter cryoablation of supraventricular tachycardia (SVT) is considered to be a safer alternative a compared with RFA. At our institution, cryoablation has become the primary interventional modality for all APs. The reported success rates of cryoablation for AP-mediated tachycardia have generally been less favorable than for RFA. However, the location of AP may influence cryoablation outcome. Furthermore, there are little data available on cryoablation of left-sided pathways.
Methods: A chart review was performed for all patients undergoing cryoablation between August 2005 and August 2007. Twenty-nine patients (mean age 13 years, range 6–18 years) were identified with SVT secondary to left-sided AP. The data collected included patient age, height, weight, date of procedure, mapping, ablation and procedure time, pathway location, success, and recurrence. Cryoablation was performed via a transseptal approach. Procedural success and recurrence rate were compared with our most recent 28 patients undergoing RFA ablation.
Results: Procedural success was achieved in 97% of patients in the cryoablation group, compared with 100% in the RFA control group. Recurrence rate in the cryoablation group was 1 of 24 (4.2%) patients compared with 4 of 28 (14%) patients in the RFA group over 12 months.
Conclusion: Cryoablation can be safely and effectively used in the treatment of left-sided AP. Long-term outcomes remain to be seen.     

Magnetocardiographic Pacemapping for Nonfluoroscopic Localization of Intracardiac Electrophysiology Catheters

The purpose of the study was to validate, in patients, the accuracy of magnetocardiography (MCG) for three-dimensional localization of an amagnetic catheter (AC) for multiple monophasic action potential (MAP) with a spatial resolution of 4 mm2. The AC was inserted in five patients after routine electrophysiological study. Four MAPs were simultaneously recorded to monitor the stability of endocardial contact of the AC during the MCG localization. MAP signals were band-pass filtered DC-500 Hz and digitized at 2 KHz. The position of the AC was also imaged by biplane fluoroscopy (XR), along with lead markers. MCG studies were performed with a multichannel SQUID system in the Helsinki BioMag shielded room. Current dipoles (5mm; 10mA), activated at the tip of the AC, were localized using the equivalent current dipole (ECD) model in patient-specific boundary element torso. The accuracy of the MCG localizations was evaluated by: (1) anatomic location of ECD in the MRI, (2) mismatch with XR. The AC was correctly localized in the right ventricle of all patients using MRI. The mean three-dimensional mismatch between XR and MCG localizations was 6 ± 2 mm (beat-to-beat analysis). The coefficient of variation of three-dimensional localization of the AC was 1.37% and the coefficient of reproducibility was 2.6 mm. In patients, in the absence of arrhythmias, average local variation coefficients of right ventricular MAP duration at 50% and 90% ofrepolarization, were 7.4% and 3.1%, respectively. This study demonstrates that with adequate signal-to-noise ratio, MCG three-dimensional localizations are accurate and reproducible enough to provide nonfluoroscopy dependant multimodal imaging for high resolution endocardial mapping of monophasic action potentials.     

S- and C-glycopeptide derivatives of an LH-RH agonist

The S- and C-glycosylated nonapeptides 1 and 2 were synthesized as analogs of the non-glycosylated LH-RH agonist buserelin (pGlu-His-Trp-Ser-Tyr-D-Ser(tBu)-Leu-Arg-Pro-NHEt) by segment condensation in solution. 1 and 2 differ from this peptide in the amino acid in position 6. In the first case (l), D-serine (tBu) is substituted by D-CySteine carrying a rhamnosyl residue, in the second case (2) D-alanine carrying a galactosyl moiety bound as C-glycoside is incorporated. The bioactivity of both glycopeptides as fertility drugs was determined from the dose dependent LH release in male rats. Additionally, in female rats the ovulation rate was assessed. As a result the analog 1 exhibits a similar biological activity as buserelin while analog 2 shows about 25% of this potency. Compared to buserelin the solubility of the analogs 1 and 2 in aqueous buffer is improved by more than two orders of magnitude due to the carbohydrate moieties. © Munksgaard 1996.     

Dental fear in children and adolescents: a comparison of forms of anxiety management practised by general and paediatric dentists

International Journal of Paediatric Dentistry 2011; 22: 60–67 Background. About 11% of children and adolescents suffer from dental fear. These young people run an increasing risk of undergoing more invasive treatments. Aim. We researched the management of dental anxiety in young patients by general and paediatric dentists as well as by trained and untrained dentists. Design. Eight hundred dentists in Germany were interviewed via e‐mail regarding their experience, treatment techniques, information material and complications during the treatment of fearful children. We also examined how difficult dentists judge the treatment of anxious children and how often they participate in continuing education courses. Results. Paediatric dentists applied a greater spectrum of management techniques than general dentists. They used more often psychotherapeutic interventions and anxiety assessment questionnaires. Dentists who frequently attend in continuing education courses judged the treatment to be less difficult and also used psychotherapeutic interventions more often. Conclusions. German paediatric dentists and dentists who take continuing education courses utilise a broader range of techniques to manage dental anxiety. They may be eminently suited to treat children with severe forms of anxiety. Therefore, dentists who treat young patients should participate in education programmes so as to reduce both the anxiety of their patients and their own anxiety.     

骨转换标志物的临床应用

骨转换生化标志物(骨转换标志物)包括多种来源于骨细胞和骨基质成分的酶或其分解产物,其在血清或尿液中的含量可反映机体骨转换的水平.故骨转换标志物可作为临床诊断代谢性骨疾病及评价其治疗效果的一项无创有效的检测指标,可按其反映骨吸收、破骨细胞数量、骨形成及成骨细胞分化等骨转换的不同方面进行分类.由于可能存在多种固有变异会影响临床上对各项骨转换标志物水平的分析,所以一项骨转换标志物不能用做诊断目的.但是联合测定同一个体的多项标志物可有效地为临床服务,如方便地用于监测抗骨质疏松药物的治疗效果,预测未来骨折的危险性及诊断肿瘤的骨转移.多项骨转换标志物的联合测定也可作为每年体检的项目之一,其改变能部分反映导致骨疾病的骨转换异常.由于其分泌具有明显的昼夜节律性,故大多数骨转换标志物的检测结果,存在较大变异,但这种变异在血标本比尿标本要小.此外,摄食可能降低多种骨转换标志物的水平,因此在空腹状态采集样本为宜.个别标志物对温度降低、溶血及反复冻融等反应敏感,所以建议血标本应置于≤-70℃温度下等份分装贮存.     

A time of change: health policy, planning and organization in Ghana

This paper presents the results of a rapid health sector policyanalysis carried out in Ghana in October 1990. Its purpose isto illustrate the dynamics of the policy debate at a time ofmajor change, and to provoke discussion about the practicalimplications of current policy directions. In addition, it demonstratesthe range and nature of issues of concern to decision makersin the Ministry of Health, Ministry of Local Government andNational Development Planning Commission. Issues discussed include:the restructuring of the Ministry of Health; resource allocationunder decentralization; health planning responsibilities atdifferent levels; the case for an intermediate level of managementin a decentralized health system; the relationship between differentforms of cost-recovery programme; the future of EPI and; theimplications of establishing a national health service. Thefinal section presents some preliminary conclusions concerningthe process of organizational change in the health sector resultingfrom decentralization policies.     

Nonfluoroscopic Localization of an Amagnetic Catheter in a Realistic Torso Phantom by Magnetocardiographic and Body Surface Potential Mapping

This study was performed to evaluate the accuracy of multichannel magnetocardiographic (MCG) and body surface potential mapping (BSPM) in localizing three-dimensionally the tip of an amagnetic catheter for electrophysiology without fluoroscopy. An amagnetic catheter (AC), specially designed to produce dipolar sources of different geometry without magnetic disturbances, was placed inside a physical thorax phantom at two different depths, 38 mm and 88 mm below the frontal surface of the phantom. Sixty-seven MCG and 123 BSPM signals generated by the 10 mA current stimuli fed into the catheter were then recorded in a magnetically shielded room. Non-invasive localization of the tip of the catheter was computed from measured MCG and BSPM data using an equivalent current dipole source in a phantom-specific boundary element torso model. The mean 3-dimensional error of the MCG localization at the closer level was 2 ± 1 mm. The corresponding error calculated from the BSPM measurements was 4 ± 1 mm. At the deeper level, the mean localization errors of MCG and BSPM were 7 ± 4 mm and 10 ± 2 mm, respectively. The results showed that MCG and BSPM localization of the tip of the AC is accurate and reproducible provided that the signal-to-noise ratio is sufficiently high. In our study, the MCG method was found to be more accurate than BSPM. This suggests that both methods could be developed towards a useful clinical tool for nonfluoroscopic 3-dimensional electroanatomical imaging during electrophysiological studies, thus minimizing radiation exposure to patients and operators.     

Nonfluoroscopic Localization of an Amagnetic Stimulation Catheter by Multichannel Magnetocardiography

This study was performed to: (1) evaluate the accuracy of noninvasive magnetocardiographic (MCG) localization of an amagnetic stimulation catheter; (2) validate the feasibility of this multipurpose catheter; and (3) study the characteristics of cardiac evoked fields. A stimulation catheter specially designed to produce no magnetic disturbances was inserted into the heart of five patients after routine electrophysiological studies. The catheter position was documented on biplane cine x-ray images. MCG signals were then recorded in a magnetically shielded room during cardiac pacing. Noninvasive localization of the catheter's tip and stimulated depolarization was computed from measured MCG data using a moving equivalent current-dipole source in patient-specific boundary element torso models. In all five patients, the MCG localizations were anatomically in good agreement with the catheter positions defined from the x-ray images. The mean distance between the position of the tip of the catheter defined from x-ray fluoroscopy and the MCG localization was 11 +/- 4 mm. The mean three-dimensional difference between the MCG localization at the peak stimulus and the MCG localization, during the ventricular evoked response about 3 ms later, was 4 +/- 1 mm calculated from signal-averaged data. The 95% confidence interval of beat-to-beat localization of the tip of the stimulation catheter from ten consecutive beats in the patients was 4 +/- 2 mm. The propagation velocity of the equivalent current dipole between 5 and 10 ms after the peak stimulus was 0.9 +/- 0.2 m/s. The results show that the use of the amagnetic catheter is technically feasible and reliable in clinical studies. The accurate three-dimensional localization of this multipurpose catheter by multichannel MCG suggests that the method could be developed toward a useful clinical tool during electrophysiological studies.