Identifying biomechanical gait parameters in adolescent boys with haemophilia using principal component analysis

Introduction

Improvements in the medical management for those with haemophilia have resulted in improved clinical outcomes. However, current treatment regimens do not alleviate all joint haemarthroses with the potential for long‐term joint deterioration remaining. The evaluation of functional activities such as gait, using standardized tools to monitor children with haemophilia is emerging.

Aim

This study explored differences in sagittal plane biomechanics of walking in adolescent boys aged 11‐18 years with haemophilia and an age‐matched group of typically developing boys.

Methods

A motion capture system and 2 force platforms were used to collect sagittal plane kinematic, kinetic and temporal spatial data during level walking. Principal component analysis (PCA) was applied to kinematic and kinetic waveform variables. Group differences in temporal spatial and principal component scores for each kinematic and kinetic variable were evaluated using independent t tests.

Results

Significant alterations (P < .05) in temporal spatial and kinetic parameters were found in adolescent boys with haemophilia. Compared with typically developing adolescent boys, boys with haemophilia walked with reduced stance phase duration and altered pattern of external ankle joint moments during push off and the beginning of swing.

Conclusion

The use of PCA rather than predetermined discriminatory variables provided additional insight into biomechanical alterations in adolescent boys with haemophilia, with adaptations occurring during terminal double support and early swing, affecting the ankle joint. This finding might be a key biomechanical marker that could be used to evaluate the joint function and the progression of early haemophilic arthropathy.     

Developing a biological age assessment equation using principal component analysis and clinical biomarkers of aging in Korean men

The purpose of the present study is to find clinically useful candidate biomarkers of aging, and using these to develop an equation measuring biological age (BA) in Korean men, then to validate the clinical usefulness of it. Among 4288 men who received medical health examinations, we selected 1588 men who met the normality criteria of each variable. We assumed that chronological ages (CA) of healthy persons represent the BA of them. Variables showing significant correlations with CA were selected. Redundant variables were excluded. We selected 11 variables: VO(2)max, percent body fat (%BF), waist circumference (WC), forced expiratory volume in 1 s (FEV1), systolic blood pressure (SBP), low density cholesterol (LDLCH), blood urea nitrogen (BUN), serum albumin (SA), erythrocyte sedimentation rate(ESR) hearing threshold (HT), and glycosylated hemoglobin (HBA1C). These 11 variables were then submitted into principal component analysis (PCA) and standardized BA scores were obtained. Using them and T-scale idea, the following equation to assess BA was developed: BA=-28.7+0.83(%BF)+0.48(WC)+0.13(SBP)-0.27(VO(2)max)+0.19(HT)-3.1(FEV1)+0.32(BUN)+0.06(LDLCH)-3.0(SA)+0.34(ESR)+4.6(HBA1C). We compared the BA of 3122 men by their fasting glucose and age level. The BA of the higher glucose level group was significantly higher than that of others at all CA levels. The selected 11 biomarkers encompassed known clinically important factors of adult diseases and functional disabilities. This BA assessment equation can be used in the general Korean male population and it proved to be clinically useful.     

主成分分析和聚类分析在胰腺炎早期诊断中的应用研究

［摘要］　目的　利用主成分分析和聚类分析对胰腺炎发病早期的生化指标进行研究,并依据其特征对胰腺炎病人进行分类。方法　搜集2011-05～2012-04住院的24例急性胰腺炎（AP）患者的血细胞分析、血生化检查单资料进行研究,主成分分析使用SPSS13.0软件进行分析,聚类分析使用SPSS13.0和SAS软件综合进行分析。结果　根据主成分分析结果可将胰腺炎发病早期的生化指标归为四类,分别是酶类相关变化、血液浓缩和炎症渗出状况、凝血功能及感染严重程度。聚类分析结果表明,对于多数病人来说,其发病具有规律性,以此为基础,可以为规范化治疗提供依据和参考。而对于脂肪酶（LIPA≥1 500 U/L）、淀粉酶（AMYL≥970 U/L）、谷草转氨酶(AST≥600 U/L)、谷丙转氨酶(ALT≥580 U/L)值较高以及血细胞压积（HCT≥0.58 L/L）及单核细胞(MON≥2.98×10⁹/L)明显异常的患者,需特别注意,从而为研究胰腺炎发病机制和制定个体化治疗方案提供指导。结论　通过主成分分析和聚类分析可以充分发掘数据信息,对病人疾病状况及时作出评价,并根据其结果对病人进行分类,从而为早诊断、早治疗及预防并发症提供依据和参考。     

The P-wave in the electrocardiogram of hypertensive patients before and after therapy

P-wave areas in the electrocardiogram (ECG) of 51 patients with hypertension and of 53 normotensive controls were measured in lead V1 using a computerised planimeter. The total area (in mm2) of P-waves was significantly larger in hypertensives than in normotensives, i.e. males 0.59 vs 0.31; females 0.55 vs 0.26 (p less than .0001) respectively. With exception of one male, the P-waves in hypertensives were either negative or biphasic with terminal negativity. In part 2 of the study, P-wave areas of 84 hypertensives were measured prior to and five years after treatment. The patients had no previous antihypertensive therapy, a diastolic blood pressure (DBP) 90-104 mmHg at the onset of the study, no ECG signs of left ventricular hypertrophy (LVH), and DBP less than 85 mmHg at the end of the trial. After five years, the mean values of the P-wave areas (in mm2) decreased in white males from 0.67 to 0.36; in white females from 0.63 to 0.42; in black males from 0.97 to 0.56; and in black females from 0.80 to 0.46. We conclude that ECG P-wave area is significantly larger in untreated hypertensives compared with normotensives. In successfully treated hypertensives, the P-wave area returns to normal values.     

Specific electrocardiographic markers of P-wave morphology in interatrial block

Background

Interatrial block (IAB; P waves ≥ 110 milliseconds), the conduction delay between the right (RA) and left atrium (LA), is depicted on the electrocardiogram (ECG) as prolonged, often bifid (“notched”), P waves with distinguishable RA and LA components. Although electrophysiologic (EP) studies give some insight on how RA and LA components are depicted on the surface ECG in normal conduction, few if at all any, have conclusively demonstrated this correlation with IAB. Using existing EP knowledge, we investigated if such P-wave markers on bedside ECGs exist in IAB and appraised their utility in IAB recognition.

Methods

We reviewed the medical records of patients admitted to a general hospital from December 1, 2004, to December 15, 2004. Of those, 151 patients had been admitted for nonacute presentations and were screened with 12-lead ECGs. Thirty-eight ECGs were excluded for nonsinus and paced rhythms, severe motion artifact, errors in lead placement, absence of adequate patient identification, and duplicate patient admissions after discharge. The remaining 113 ECGs were then evaluated for IAB. Sixty-three patients who did not have IAB formed the control (group A), whereas of the remaining 50 patients with IAB, 24 who had past ECGs for comparison formed group B1 and 26 without past ECGs formed group B2. Groups were compared for common clinical comorbidities, whereas sensitivity and specificity were calculated for significant P-wave markers. P values were also calculated, with a value of <.05 considered significant.

Results

Clinical characteristics of patients in all groups were statistically comparable. Overall, almost all P waves in patients with IAB (groups 1 and 2) appeared “notched” (94%, P < .0001; sensitivity, 75%; specificity, 94% for IAB recognition; positive predictive value, 94%). P-wave RA components were commonly depicted as “domes,” whereas their LA counterparts formed “spikes” (48%, P < .0001; sensitivity 96%; specificity, 70% for IAB recognition). When groups B1 and B2 were compared with increased accuracy, more P waves in group B1 were noted to have notches and had easily discernible RA and LA components; often, the RA duration is longer than the LA duration. In addition, more “dome-and-spike” complexes could be determined when past ECGs were present for comparison. These markers could be found on any bedside ECG lead in IAB but were predominant on leads II and V3 to V6.

Conclusions

Specific noninvasive surface markers such as P-wave “dome-and-spike” complexes and “notches” in any lead (predominantly leads II and V3-V6) on the bedside ECG could alert clinicians to measure P waves and so identify IAB.     

颈内动脉颅外段狭窄超声检测参数的判别分析和主成分分析

目的通过对彩色多普勒血流显像（CDFI）检查颈内动脉（ICA）颅外段狭窄相关的血流动力学测量参数进行判别和主成分分析，完善判别方法。方法以华扬等提出的测量参数为标准，对86例ICA轻度狭窄和93例ICA中、重度狭窄患者进行CDFI常规检测，ICA中、重度狭窄患者均经全脑数字减影血管造影（DSA）诊断证实。应用判别分析（Fisher差别法）和主成分分析方法对CDFI测量的颈内动脉狭窄段收缩期峰值流速（PSVICA）、颈内动脉狭窄段舒张期峰值流速（EDVICA）和PSVICA／颈内动脉狭窄远段收缩期峰值流速（PSVDIS）数值进行统计学分析。并推导函数式。结果①轻、中、重度狭窄的Fisher线性判别函数式分别为：Y1=0．105×PSVICA＋0．142×EDVICA＋1．247×PSVICA／PSVDIS-10．769；Y2=0．022×PSVICA＋0．411×EDVICA＋12．552×PSVICA／PSVDIS-36．773；Y3=0．145×PSVICA＋0．560×EDVICA＋14．018×PSVICA/PSVDIS-88．392。②由主成分分析得到的轻、中、重度狭窄得分综合评价函数式分别为：f1=0．017291×PSVICA＋0．016535×EDVICA＋3．626682×PSVICA／PSVDIS-7．225329；f2=0．005747×PSVICA＋0．040419×EDVICA＋0．506257×PSVICA／PSVDIS-5．675821；f3=0．006775×PSVICA＋0．030777×EDVICA＋0．446399×PSVICA／PSVDIS-7．842303。③主成分分析判别狭窄程度临界值，轻度以下为f1〈1．89；中度为f1〉1．89，同时f3〈-1．7；重度为f3〉-1．71。临界值判断与DSA的符合率达98．9％。结论不断完善的CDFI检测方法是检查ICA狭窄重要、快捷的手段。其中采用主成分分析，利用临界值判断，与DSA的符合率很高。     

Reproducibility of the signal-averaged electrocardiogram using individual lead analysis

The aim of the study was to evaluate the immediate reproducibilityof time domain parameters in the signal averaged electrocardiogramusing a new method for endpoint determination in individualFrank leads. The method is based on a statistical model of theelectrocardiogram (ECG) in which maximum likelihood (ML) estimationis employed. The reproducibility of the ML method was comparedto that of conventional time domain analysis using the vectormagnitude (VM) of Frank leads. Fifty-nine patients were includedin the study and two consecutive ECGs were recorded for signalaveraging. The results showed that the mean of the absolutedifference of the filtered QRS duration (QRSD) between two consecutiverecordings was significantly lower for the ML method than theconventional method when employing 60 H_z highpass filtering(2.1 ± 2.2 ms vs 5.9 ± 10.2 ms, P < 0.05).Moreover, the ML method resulted in a significantly longer QRSDcompared to the VM-based method (P < 0.05). The terminalamplitude of the QRS complex (RMS40) showed a greater variabilitythan the QRSD for both methods, although the ML method was associatedwith a higher reproducibility than the VM method for the 60Hz filter. These findings may contribute to a better identificationof patients at high risk of ventricular arrhythmias. A reductionin the number of measurement errors has important implicationswhen QRS changes are analysed over time.     

利用主成分分析提取人类肝纤维化声像图的纹理特征

目的：探讨利用主成分分析（principal component analysis,PCA）的方法提取人类肝脏纤维化声像图纹理特征的价值。方法采集186例有肝脏组织穿刺病理肝纤维化分期（S0～S4）结果的慢性乙型肝炎患者的标准化声像图,提取声像图纹理的灰度共生矩阵（gray level co-occurrence matrix,GLCM）参数。采用PCA 对5类186幅人肝纤维化声像图纹理的14个GLCM参数进行分析,从中提取主要成分。分别利用这两套参数建立判别分析模型对肝纤维化声像图进行分类。结果获得的3个主要成分对人肝纤维化声像图纹理解释的累计贡献率为96．12％。交互检验表明建立在3个主要成分和14个原始参数基础上的判别分析模型分别能够对55．9％和60．8％的病例进行准确分类。结论采用PCA提取的主成分不仅能减少数据量,而且获得了与原始参数类似的分类精度。     

基于主成分分析法的某医院老年病科医疗质量与效率的评价分析

目的通过对某医院老年病科2007—2012年的医疗工作质量进行综合评价,为医院和上级部门提供客观、科学的分析管理依据。方法选择10项反映医疗质量和运行效率的指标,应用主成分分析法进行统计分析,对6年的医院老年病科医疗工作做出定量综合评价。结果6年来某医院老年病科医疗工作综合评价显示,医疗质量逐年上升,运行效率逐年下降。结论评价某医院老年病科医疗质量需要针对效率指标和质量指标进行综合分析,以便为老年病科管理部门提供客舰、合理、可行的管理依据。     

Influence of age on atrial activation as measured by the P-wave signal-averaged electrocardiogram

We used the P-wave signal-averaged electrocardiogram (SAECG) prospectively in 93 healthy volunteers of different ages and observed: (1) a positive correlation between P-wave duration on the SAECG and age (r = 0.39, p < 0.0001); and (2) the proportion of subjects with prolonged P-wave duration was increased with older age. These findings confirm the hypothesis that age-related atrial conduction delay in healthy subjects is present, and detectable by the P-wave SAECG.     

Linkage analysis of human systemic lupus erythematosus-related traits: a principal component approach.

OBJECTIVE: To identify chromosomal regions containing genes involved in the susceptibility to human systemic lupus erythematosus (SLE)-related traits. METHODS: In the context of a genome scan, we analyzed 101 SLE-affected sibpairs with respect to dermatologic, renal, immunologic, hematologic, neurologic, cardiopulmonary, and arthritic characteristics. Phenotypes were redefined in terms of principal components, which are synthetic variables composed of linear combinations of the original traits. Using 9 principal components obtained from these 7 traits plus age at SLE onset and race, we analyzed genome scan data with the multivariate version of the new Haseman-Elston regression model. RESULTS: The largest linkage for an individual trait was on chromosome 2 at 228 cM (immunologic; P = 0.00048). The most significant linkage to an individual principal component was on chromosome 4 at 208 cM (P = 0.00007). The largest multivariate linkage was on chromosome 7 at 69 cM (P = 0.0001). Of the individual organ systems, dermatologic involvement had the largest effect (P = 0.0083) at this peak at 7p13 on chromosome 7. Further analyses revealed that malar rash, a subtype of dermatologic involvement, was linked significantly (P = 0.00458) to this location. CONCLUSION: These results provide evidence of the presence and locations of genes that are involved in the genetic susceptibility to SLE-related traits in humans.     

Peculiarities of morphology and mechanisms of pathogenesis of hypertrophic cardiomyopathy

Understanding the molecular basis and cell mechanisms, clinical course, and treatment of hypertrophic cardiomyopathy (HCMP) has progressed substantially in the last decade. The majority of genetic mutations associated with HCMP occur in genes encoding sarcomeric proteins, which are expressed only in cardiomyocytes. The spectrum of morphological features of HCMP includes: hypertrophy of myocardium, myocardial disarray, interstitial fibrosis, mitral valve abnormalities, and microvascular remodeling, is indicative of the involvement of other cell lineages. The link between sarcomeric gene defects and these HCM phenotypes remains elusive. Based on novel insights provided by cardiac developmental biology we can create new effective methods of treatment of this complex disease.