Computational simulations of flow dynamics and blood damage through a bileaflet mechanical heart valve scaled to pediatric size and flow

Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23 mm St. Jude Medical (SJM) Regent^™ valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow with thousands of suspended platelets for cases of adult, child, and infant BMHV flows. Adult BMHV flows demonstrate more disorganized small-scale flow features, but pediatric flows are associated with higher fluid shear stresses. Platelet damage in the pediatric cases is higher than in adult flow, highlighting thrombus complication dangers of pediatric BMHV flows. This does not necessarily suggest clinically important differences in thromboembolic potential. Highly damaged platelets in pediatric flows are primarily found far downstream of the valve, as there is less flow recirculation in pediatric flows. In addition, damage levels are well below expected thresholds for platelet activation. The extent of differences here documented between the pediatric and adult cases is of concern, demanding particular attention when pediatric valves are designed and manufactured. However, the differences between the pediatric and adult cases are not such that development of pediatric sized valves is untenable. This study may push for eventual approval of prosthetic valves resized for the pediatric population. Further studies will be necessary to determine the validity and potential thrombotic and clinical implications of these findings.     

Does adiposity affect muscle function during walking in children?

The biomechanical mechanisms responsible for the altered gait in obese children are not well understood, particularly as they relate to increases in adipose tissue. The purpose of this study was to test the hypotheses that as body-fat percentage (BF%) increased: (1) knee flexion during stance would decrease while pelvic obliquity would increase; (2) peak muscle forces normalized to lean-weight would increase for gluteus medius, gastrocnemius, and soleus, but decrease for the vasti; and (3) the individual muscle contributions to center of mass (COM) acceleration in the direction of their primary function(s) would not change for gluteus medius, gastrocnemius, and soleus, but decrease for the vasti. We scaled a musculoskeletal model to the anthropometrics of each participant (n=14, 8–12 years old, BF%: 16–41%) and estimated individual muscle forces and their contributions to COM acceleration. BF% was correlated with average knee flexion angle during stance (r=−0.54, p=0.024) and pelvic obliquity range of motion (r=0.78, p<0.001), as well as with relative vasti (r=−0.60, p=0.023), gluteus medius (r=0.65, p=0.012) and soleus (r=0.59, p=0.026) force production. Contributions to COM acceleration from the vasti were negatively correlated to BF% (vertical— r=−0.75, p=0.002, posterior— r=−0.68, p=0.008), but there were no correlation between BF% and COM accelerations produced by the gastrocnemius, soleus and gluteus medius. Therefore, we accept our first, partially accept our second, and accept our third hypotheses. The functional demands and relative force requirements of the hip abductors during walking in pediatric obesity may contribute to altered gait kinematics.     

Spatiotemporal switching signals for cancer stem cell activation in pediatric origins of adulthood cancer:Towards a watch-and-wait lifetime strategy for cancer treatment

Pediatric origin of cancer stem cell hypothesis holds great promise and potential in adult cancer treatment, however; the road to innovation is full of obstacles as there are plenty of questions left unanswered. First, the key question is to characterize the nature of such stem cells (concept). Second, the quantitative imaging of pediatric stem cells should be implemented(technology). Conceptually, pediatric stem cell origins of adult cancer are based on the notion that plasticity in early life developmental programming evolves local environments to cancer. Technologically, such imaging in children is lacking as all imaging is designed for adult patients. We postulate that the need for quantitative imaging to measure space-time changes of plasticity in early life developmental programming in children may trigger research and development of the imaging technology. Such quantitative imaging of pediatric origin of adulthood cancer will help develop a spatiotemporal monitoring system to determine cancer initiation and progression. Clinical validation of such speculative hypothesis-that cancer originates in a pediatric environment-will help implement a wait-andwatch strategy for cancer treatment.     

Ventricular tachycardia ablation in children

IntroductionThe ablation of ventricular tachycardia, including premature ventricular contractions, is an approved, albeit infrequent procedure in pediatric patients. Data are scarce regarding the outcomes of this procedure. The purpose of this study was to share a high-volume center experience and patient outcomes for catheter ablation of ventricular ectopy and ventricular tachycardia in pediatric population.MethodsData were retrieved from the institutional data bank. Outcomes over time were evaluated, and procedural details were compared.ResultsA total of 116 procedures were performed on 102 pediatric patients between July 2009 and May 2021 at the Rajaie Cardiovascular Medical and Research Center in Tehran, Iran. Ablation was not performed in 4 procedures (3.4%) due to high-risk substrates. Of the remaining 112 ablations performed, 99 (88.4%) were successful. However, one patient died due to a coronary complication. There were no significant differences observed in early ablation results based on patients' age, sex, cardiac anatomy, or ablation substrates (P > 0.05). Follow-up records were available for 80 procedures, and 13 (16.3%) of those experienced recurrence. During long-term follow-up, none of the variables mentioned above were statistically different between patients with or without arrhythmia recurrence.ConclusionThe overall success rate of pediatric ventricular arrhythmia ablation is favorable. We found no significant predictor for the procedural success rate concerning acute and late outcomes. Larger multicenter studies are needed to elucidate the predictors and outcomes of the procedure.     

脓毒症患儿预后的影响因素分析及pSOFA评分、PCIS评分及早期血乳酸测定的预测价值探讨

摘要 目的：分析脓毒症患儿预后的影响因素,并探讨儿科序贯器官衰竭评估（pSOFA）评分、小儿危重病例评分法（PCIS）评分及早期血乳酸（Lac）测定对预后的预测价值。方法：选取2020年1月～2022年5月我院儿童医学中心收治的107例脓毒症患儿,根据脓毒症患儿28 d生存情况分为死亡组48例和存活组59例。收集患儿临床资料,对患儿进行pSOFA评分、PCIS评分评价和血Lac检测。采用单因素和多因素Logistic回归分析脓毒症患儿死亡的影响因素,受试者工作特征（ROC）曲线分析pSOFA评分、PCIS评分和血Lac水平对脓毒症患儿死亡的预测价值。结果：107例脓毒症患儿28 d死亡率为44.86％（48/107）。死亡组脓毒症分级、合并器官损伤≥3个比例、机械通气比例、pSOFA评分、白细胞计数、D-二聚体、C反应蛋白、降钙素原、血Lac水平高于存活组,机械通气时间长于存活组,PCIS评分、血小板计数、白蛋白水平低于存活组（P＜0.05）。多因素Logistic回归分析显示,严重脓毒症、脓毒性休克、合并≥3个器官损伤、机械通气、pSOFA评分增加、D-二聚体升高、血Lac升高为脓毒症患儿死亡的独立危险因素,PCIS评分增加、白蛋白升高为独立保护因素（P＜0.05）。ROC曲线分析显示,pSOFA评分、PCIS评分和血Lac水平联合预测脓毒症患儿死亡的曲线下面积大于各指标单独预测。结论：脓毒症分级、合并器官损伤、机械通气、D-二聚体、白蛋白、pSOFA评分、PCIS评分、血Lac为脓毒症患儿预后的影响因素,pSOFA评分、PCIS评分和血Lac水平联合预测脓毒症患儿死亡风险的价值较高。     

小儿推拿疗法联合中药热奄包治疗小儿夜啼的疗效及对睡眠质量和生长发育的影响

摘要 目的：探讨小儿推拿疗法联合中药热奄包治疗小儿夜啼的疗效及对睡眠质量和生长发育的影响。方法：选取2019年4月~到2021年8月期间石家庄市中医院收治的120例夜啼患儿作为研究对象。根据双色球法将患儿分为对照组（常规药物治疗）和观察组（对照组的基础上接受小儿推拿疗法联合中药热奄包治疗）,各为60例。对比两组疗效、中医证候评分、睡眠质量、生长发育相关指标和不良反应发生情况。结果：与对照组相比,观察组的临床总有效率明显升高（P<0.05）。与对照组相比,观察组治疗1周后啼哭、腹喜按摩、睡喜蜷曲、四肢欠温、大便稀溏、小便色清评分更低（P<0.05）。与对照组相比,观察组治疗1周后白天睡眠时间、夜间睡眠时间更长,夜间清醒时间更短,夜醒次数更少（P<0.05）。与对照组相比,观察组治疗6个月后年龄别体质量Z值（WAZ）、年龄别身长Z值（LAZ）、身长别体质量Z值（WLZ）和头围Z值（HCZ）更大（P<0.05）。治疗期间两组均未出现不良反应。结论：小儿推拿疗法联合中药热奄包治疗小儿夜啼,可有效改善患儿临床症状,提高睡眠质量,促进生长发育。     

Disparities in survival improvement for U.S. childhood and adolescent cancer between 1995 and 2019: An analysis of population-based data

BackgroundAlthough treatment advances have increased childhood and adolescent cancer survival, whether patient subgroups have benefited equally from these improvements is unclear.MethodsData on 42,865 malignant primary cancers diagnosed between 1995 and 2019 in individuals ≤ 19 years were obtained from 12 Surveillance, Epidemiology, and End Results registries. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for cancer-specific mortality by age group (0–14 and 15–19 years), sex, and race/ethnicity were estimated using flexible parametric models with a restricted cubic spline function in each of the periods: 2000–2004, 2005–2009, 2010–2014 and 2015–2019, versus 1995–1999. Interactions between diagnosis period and age group (children 0–14 and adolescents 15–19 years at diagnosis), sex, and race/ethnicity were assessed using likelihood ratio tests. Five-year cancer-specific survival rates for each diagnosis period were further predicted.ResultsCompared with the 1995–1999 cohort, the risk of dying from all cancers combined decreased in subgroups defined by age, sex and race/ethnicity with HRs ranging from 0.50 to 0.68 for the 2015–2019 comparison. HRs were more variable by cancer subtype. There were no statistically significant interactions by age group (P_interaction=0.05) or sex (P_interaction=0.71). Despite non-significant differences in cancer-specific survival improvement across different races and ethnicities (P_interaction=0.33) over the study period, minorities consistently experienced inferior survival compared with non-Hispanic Whites.ConclusionsThe substantial improvements in cancer-specific survival for childhood and adolescent cancer did not differ significantly by different age, sex, and race/ethnicity groups. However, persistent gaps in survival between minorities and non-Hispanic Whites are noteworthy.     

Localization of the human alpha-globin structural gene to chromosome 16 in somatic cell hybrids by molecular hybridization assay

We have used 16 human × mouse somatic cell hybrids containing a variable number of human chromosomes to demonstrate that the human α-globin gene is on chromosome 16. Globin gene sequences were detected by annealing purified human α-globin complementary DNA to DNA extracted from hybrid cells. Human and mouse chromosomes were distinguished by Hoechst fluorescent centromeric banding, and the individual human chromosomes were identified in the same spreads by Giemsa trypsin banding. Isozyme markers for 17 different human chromosomes were also tested in the 16 clones which have been characterized. The absence of chromosomal translocation in all hybrid clones strongly positive for the α-globin gene was established by differential staining of mouse and human chromosomes with Giemsa 11 staining. The presence of human chromosomes in hybrid cell clones which were devoid of human α-globin genes served to exclude all human chromosomes except 6, 9, 14 and 16. Among the clones negative for human α-globin sequences, one contained chromosome 2 (JFA 14a 5), three contained chromosome 4 (AHA 16E, AHA 3D and WAV R4D) and two contained chromosome 5 (AHA 16E and JFA14a 13 5) in >10% of metaphase spreads. These data excluded human chromosomes 2, 4 and 5 which had been suggested by other investigators to contain human globin genes. Only chromosome 16 was present in each one of the three hybrid cell clones found to be strongly positive for the human α-globin gene. Two clones (WAIV A and WAV) positive for the human α-globin gene and chromosome 16 were counter-selected in medium which kills cells retaining chromosome 16. In each case, the resulting hybrid populations lacked both human chromosome 16 and the α-globin gene. These studies establish the localization of the human α-globin gene to chromosome 16 and represent the first assignment of a nonexpressed unique gene by direct detection of its DNA sequences in somatic cell hybrids.     

瑞芬太尼、芬太尼对小儿扁桃体切除术中应激反应和苏醒期躁动的影响

目的:探讨瑞芬太尼、芬太尼对小儿扁桃体切除术中应激反应以及苏醒期躁动的影响。方法:选择2012年1月至2012年12月期间择期行扁桃体切除手术的患儿80例为研究对象,将其分随机为瑞芬太尼组(40例)和芬太尼组(40例),比较两组患者不同时间应激反应指标(ACTH、COR、IL-6)、苏醒时间、躁动评分、躁动发生率以及RamSay镇静评分,探讨两种麻醉药物的临床应用价值。结果:两组术前ACTH、COR、IL-6的基础应激指标比较,差别无统计学意义(P0.05)。瑞芬太尼组及芬太尼组术毕该三项指标较术前升高,术后1d较术毕有回落,差别有统计学意义(P0.05);瑞芬太尼组术毕﹑术后1d的各项指标均远远低于芬太尼组,差别有统计学意义(P0.05)。瑞芬太尼组苏醒时间明显少于芬太尼组,躁动评分明显低于芬太尼组,躁动发生率明显低于芬太尼组,RamSay镇静评分明显高于芬太尼组,差别有统计学意义(P0.05)。结论:瑞芬太尼引起的应激反应明显弱于芬太尼组,且其苏醒期躁动情况明显优于芬太尼组,值得进一步推广应用。     

氯胺酮加丙泊酚与芬太尼加丙泊酚用于学龄前 小儿非心脏手术的麻醉效果比较

目的:比较芬太尼加丙泊酚与氯胺酮加丙泊酚用于学龄前小儿非心脏手术的麻醉效果。方法:患儿70例,随机分为两组,F组(n=35),用芬太尼2-3 ug／kg,阿曲库铵0．5 mg／kg,丙泊2-3 mg／kg,静脉注射诱导插管,然后微泵持续注射芬太尼0．03-0．06 ug/kg．min-1,阿曲库铵4-8 ug/kg．min-1,丙泊酚80-150 ug／kg．min-1,K组(n=35),用氯胺酮1-1．5 mg／kg,阿曲库铵0．5 mg/kg,丙泊酚2-3 mg／kg,静脉注射诱导插管,然后微泵持续注射氯胺酮30-60 ug／kg．min-1,阿曲库铵与丙泊酚用量同F组,根据术中的情况予以调整。分别记录两组病例在用药前后的收缩压(SBP)、舒张压(DBP)、心率(HR)、麻醉效果、停药至导管拔除时间,以及拔管后因气道梗阻再次插管等情况。结果:K组病例在麻醉诱导时循环稳定,拔管后无呼吸抑制的发生,但术毕拔管的时间延长,F组病例麻醉诱导时HR、SBP、DBP降低明显,拔管后有3例气管痉挛致呼吸抑制重新插管。结论:氯胺酮复合丙泊酚用于学龄前小儿非心脏手术的麻醉,麻醉效果确切,可控性强,麻醉诱导平稳,术中易于调整,术毕拔管虽时间略为延长,但可避免呼吸抑制的发生,较为安全。