Zinc-induced alterations in contractile properties of rat diaphragm muscle in vitro

The effect of zinc ions on the isometric contraction of rat diaphragm muscles in the presence and in the absence of external calcium was studied. Using a transducer, the isometric force was measured as a function of supramaximal electrical stimulation, either directly or indirectly applied to the muscle. The following parameters were measured: peak twitch tension, PT, twitch contraction time, CT, relaxation half-time, RT-1/2, and peak rates of tension increase and decrease, +dP/dt and -dP/dt. The following zinc-induced alterations were observed: an increase of the PT; a decrease of the RT-1/2; an increase in the +dP/dt and -dP/dt. The CT was not changed significantly. Our results suggest that zinc ions have a positive inotropic effect on isolated diaphragm muscle. The increase in PT may be explained by a zinc-activated Ca²⁺ uptake by sarcoplasmic reticulum. This was followed by an increase in the rate of rise of tension development, which was secondary to increased -dP/dt. The mechanism(s) by which extracellular Ca²⁺ contributes to this action of zinc is not known.     

低氧对大鼠隔肌放电的影响

目的:探讨睡眠中间歇低氧对大鼠肠肌放电的影响.方法:大鼠分别给予吸入空气,持续低氧和间歇低氧气体,在1 d,3d,7 d,28 d后测定大鼠膈肌放电的情况及采动脉血行血气分析,分析大鼠膈肌放电在不同时期有何不同及其与酸碱平衡之间的关系.结果:与对照组比较,大鼠膈肌放电面积及膈肌放电频率振幅仅在间歇低氧28 d组无统计学...     

The co-occurrence of congenital diaphragmatic hernia, esophageal atresia/tracheoesophageal fistula, and lung hypoplasia

BACKGROUND: Two severe birth defects, congenital diaphragmatic hernia (CDH) and esophageal atresia (EA) with or without tracheoesophageal fistula (TEF), have traditionally been analyzed separately in epidemiological studies. Lung hypoplasia (LH), part of the CDH spectrum, is not usually associated with EA/TEF, yet both are foregut malformations. METHODS: We conducted an epidemiological study of two combinations of the defects in the population of 3,318,966 live births and stillbirths monitored from 1983 to 1996 by the California Birth Defects Monitoring Program (CBDMP). RESULTS: A total of 433 cases had a Bochdalek type CDH/LH (0.13 per 1000 births), 893 had EA/TEF (0.27 per 1000 births), and 646 had LH (0.19 per 1000 births). Among them, 18 cases had CDH/LH with EA/TEF (0.005 per 1000 births), and 53 had EA/TEF and LH (0.02 per 1000 births); both prevalences are significantly higher than expected. Sixteen of 17 cases of CDH/LH with EA/TEF, and 34 of 40 cases of EA/TEF with LH were stillborn or died; 72% and 74%, respectively, had an autopsy. The male to female sex ratios were 1.43 and 1.13, respectively. In both groups, infants had similar proportions of additional severe defects, except for genitourinary and anal defects and syndromes/associations, which were more prevalent in the EA/TEF with LH group. We reviewed human studies and experimental animal models for factors reported to cause any combination of the defects. CONCLUSIONS: Several genetic and environmental factors could affect the significant co-occurrence of the defects. Future studies should include storage of patients' biological materials for DNA analysis, karyotyping, and environmental exposure evaluation.     

Distal 4p microdeletion in a case of Wolf-Hirschhorn syndrome with congenital diaphragmatic hernia

BACKGROUND: Wolf-Hirschhorn syndrome (WHS) is a well-known genetic condition characterized by typical facial anomalies, midline defects, skeletal anomalies, prenatal and postnatal growth retardation, hypotonia, mental retardation, and seizures. Affected patients with a microdeletion on distal 4p present a milder phenotype that lacks congenital malformations. WHS is rarely associated with congenital diaphragmatic hernia (CDH), and only 8 cases are reported in the literature. In almost all cases of CDH and WHS a large deletion of the short arm of chromosome 4 is present. CASE: A microdeletion of 2.6 Mb on distal 4p associated with CDH and multiple congenital malformations (i.e., cleft palate) is reported for the first time. CONCLUSIONS: Such a microdeletion should prompt a molecular study for WHS when in a fetus/newborn with CDH the association with cleft lip/palate and typical facial appearance (flat facial profile, hypertelorism) is found.     

Diaphragmatic stimulation: a case of atrial lead dislodgement and right atrium perforation

We report a 48 year old male who presented with diaphragmatic stimulation. The biventricular implantable cardioverter and defibrillator (CRT-D) was implanted two weeks before admission and active fixation lead caused perforation of the right atrial wall. Echocardiography did not demonstrate pericardial effusion but Chest X-ray and computed tomography (CT) visualized the atrial screw helix outside the right atrial wall, penetrating through the right lung middle lobe. There was no atrial capture. After changing the pace mode DDDR to VVIR, diaphragmatic stimulation was disappeared. The atrial lead was repositioned and fixed again. During the hospital admission and after that the patient was well and free of any symptoms.     

Pulmonary hypertension in human newborns with congenital diaphragmatic hernia is associated with decreased vascular expression of nitric-oxide synthase

The molecular basis of the pathogenesis of pulmonary hypertension (PH) associated with congenital diaphragmatic hernia (CDH) is poorly understood. Variation in responses to therapeutic strategies such as nitric oxide (NO) inhalation and extracorporeal membrane oxygenation (ECMO) in patients with CDH remains a major problem in pediatric critical care. We investigated the expression pattern of NO-generating enzyme nitricoxide synthase (NOS) (both endothelial [eNOS] and inducible [iNOS] isoforms) in the lungs of CDH patients with PH and evaluated the influence of ECMO on the expression levels of these genes in an attempt to understand the underlying molecular mechanisms. Lung autopsy specimens from 23 cases of CDH not treated by ECMO and 10 ECMO-treated CDH cases were studied and compared with 11 age-matched controls. Expression of iNOS and eNOS was assessed by immunohistochemistry and video-image analysis. Expression of iNOS in the endothelium of small pulmonary arteries (external diameter≤200 μm) was significantly lower in CDH cases that had not received ECMO treatment (p=0.04). ECMO-treated CDH cases did not differ from controls in iNOS expression. Alveclar macrophages (CD68⁺ cells), of which the number also was increased, showed significantly enhanced staining for iNOS in CDH cases (p=0.03) compared with controls. The observed decrease in pulmonary expression of iNOS in patients with CDH suggests a potential role in the pathogenesis of pulmonary hypertension in newborns with CDH. ECMO treatment was correlated with induction of this enzyme, which may result in NO-mediated vasodilatation and thereby transiently reduce the pulmonary hypertension in CDH.     

Development of an Optimal Diaphragmatic Hernia Rabbit Model for Pediatric Thoracoscopic Training

Our objectives were to standarize the procedure needed to reproduce a similar surgical scene which a pediatric surgeon would face on repairing a Bochdalek hernia in newborns and to define the optimal time period for hernia development that achieve a realistic surgical scenario with minimimal animal suffering. Twenty New Zealand white rabbits weighing 3–3.5 kg were divided into four groups depending on the time frame since hernia creation to thoracoscopic repair: 48 h, 72 h, 96 h and 30 days. Bochdalek trigono was identified and procedures for hernia creation and thoracoscopic repair were standarized. Blood was collected for hematology (red blood cells, white blood cells, platelets, hemoglobin and hematocrit), biochemistry (blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and creatine kinase) and gas analysis (arterial blood pH, partial pressure of oxygen, partial pressure of carbón dioxide, oxygen saturation and bicarbonate) at baseline and before the surgial repairment. Glucocorticoid metabolites concentration in faeces was measured. Thoracoscopy video recordings were evaluated by six pediatric surgeons and rated from 0 to 10 according to similarities with congenital diaphragmatic hernia in newborn and with its thoracoscopic approach. Statistical methods included the analysis of variance, and comparisons between groups were followed by a post-hoc Tukey’s test. Fourty -eight h showed to be the optimal time frame to obtain a diaphragmatic hernia similar to newborn scenario from a surgical point of view with minimal stress for the animals.     

Nutrient intakes in women and congenital diaphragmatic hernia in their offspring

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a severe birth defect where there is an opening in the diaphragm through which a portion of the abdominal contents protrudes into the thoracic cavity. The etiologies of CDH remain unknown, although experimental animal data suggest dietary factors might play a role. This study examined whether maternal nutrient intakes were associated with delivering infants with CDH. METHODS: We analyzed infants with isolated CDH who were born from 1997 to 2003 and recruited into the National Birth Defects Prevention Study (NBDPS), a multisite, population‐based case‐control study. Exposure data were obtained from telephone interviews, which were completed within 24 months after delivery, and were available for 377 case mothers and 5,008 control mothers. A food frequency questionnaire was used to derive nutrient intakes during the year before pregnancy. RESULTS: A crude OR of 0.6 (95% CI: 0.3–1.0) was observed for higher intake of choline. Elevated ORs (1.4 to 1.7) were found for lower intakes of choline, cysteine, methionine, and protein. Among women who took vitamin supplements, higher intakes of B vitamins (i.e., folate, vitamin B1, B2, B6, and B12), minerals (i.e., calcium, iron, magnesium, and zinc), and vitamin E were inversely associated with CDH (ORs from 0.7–0.3). Moreover, among women who did not take vitamin supplements, lower intakes of calcium, retinol, selenium, vitamin B12, and vitamin E had positive associations with CDH (ORs from 1.4 to 2.1). CONCLUSIONS: Our observations contribute to a limited body of evidence suggesting a woman's periconceptional diet might be associated with CDH in her offspring. Birth Defects Research (Part A), 2008. © 2007 Wiley‐Liss, Inc.     

Biomarkers of the one‐carbon pathway in association with congenital diaphragmatic hernia

Homocysteine is an intermediate of the one‐carbon (1‐C) pathway and increased concentrations have been related to neural crest‐related congenital anomalies. The neural crest and the 1‐C pathway might be involved also in the etiology of Congenital Diaphragmatic Hernia (CDH). In 22 CDH and 28 control newborns and their mothers, general characteristics were obtained by standardized questionnaires. The 1‐C pathway intermediates total homocysteine (tHcy), S‐adenosylmethionine (SAM), and S‐adenosylhomocysteine (SAH) were determined in cord blood. Correlations between maternal and newborn factors and risk estimates were investigated by univariate and multivariable logistic regression analyses. Birth weight (2962 vs. 3418 gram; p < 0.001) was lower and gestational age (270 vs. 277 days; p = 0.006) was shorter in case children. Control mothers were slightly older (32 vs. 35 year; p = 0.05). Other characteristics were comparable between case and control children and mothers. The concentrations of homocysteine, SAM and SAH, and the SAM/SAH ratio were comparable (tHcy: 8.57 vs. 8.56 μmol/l, p = 0.99; SAM: 152.7 vs. 157.3 nmol/l, p = 0.76; SAH: 43.5 vs. 48.9, p = 0.26; ratio: 3.8 vs. 3.5, p = 0.50). Maternal and newborn characteristics were not correlated to the biomarker concentrations. In conclusion, the biomarkers of methylation determined in cord blood are not associated with CDH risk. Maternal and child characteristics could not predict newborn biomarker concentrations of the 1‐C pathway. Birth Defects Research (Part A) 2012. © 2012 Wiley Periodicals, Inc.     

Prenatal administration of retinoic acid upregulates insulin-like growth factor receptors in the nitrofen-induced hypoplastic lung

BACKGROUND : Pulmonary hypoplasia (PH) is the main cause of mortality in newborns with congenital diaphragmatic hernia (CDH). Prenatal administration of retinoic acid (RA) stimulates alveologenesis in the nitrofen‐induced pulmonary hypoplasia. Insulin‐like growth factor receptors (IGFRs) play a crucial role in alveologenesis during lung development. We recently demonstrated that IGFRs were downregulated in later stages of lung development in the nitrofen CDH model. Several studies suggest the ability of RA to regulate insulin‐like growth factor signaling. We hypothesized that IGFRs pulmonary gene expression is upregulated after the administration of RA in the nitrofen‐induced CDH model. METHODS : Pregnant rats were exposed to either olive oil or nitrofen on day 9 (D9) of gestation. RA was given intraperitoneally on days D18, D19, and D20. Fetal lungs were dissected on D21 and divided into control, control + RA, CDH, and CDH + RA group. IGFRs gene and protein expression were determined using RT‐PCR and immunohistochemistry. RESULTS : mRNA expression levels of IGFRs were significantly increased in control + RA and CDH + RA compared with CDH group. Immunoreactivity of IGFRs was markedly increased in control + RA and CDH + RA compared with CDH lungs. CONCLUSIONS : Upregulation of pulmonary gene and protein expression of IGFRs after prenatal RA treatment in the nitrofen model suggests that RA may promote lung growth by stimulating IGFRs mediated alveologenesis. Birth Defects Res (Part B) 92:148–151, 2011. © 2011 Wiley‐Liss, Inc.     

Early development of the primordial mammalian diaphragm and cellular mechanisms of nitrofen‐induced congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequently occurring cause of neonatal respiratory distress and is associated with high mortality and long‐term morbidity. Evidence from animal models suggests that CDH has its origins in the malformation of the pleuroperitoneal fold (PPF), a key structure in embryonic diaphragm formation. The aims of this study were to characterize the embryogenesis of the PPF in rats and humans, and to determine the potential mechanism that leads to abnormal PPF development in the nitrofen model of CDH. Analysis of rat embryos, and archived human embryo sections, allowed the timeframe of PPF formation to be determined for both species, thus delineating a critical period of diaphragm development in relation to CDH. Experiments on nitrofen‐exposed NIH 3T3 cells in vitro led us to hypothesize that nitrofen might cause diaphragmatic hernia in vivo by two possible mechanisms: through decreased cell proliferation or by inducing apoptosis. Data from nitrofen‐exposed rat embryos indicates that the primary mechanism of nitrofen teratogenesis in the PPF is through decreased cell proliferation. This study provides novel insight into the embryogenesis of the PPF in rats and humans, and it indicates that impaired cell proliferation might contribute to abnormal diaphragm development in the nitrofen model of CDH. Birth Defects Research (Part A) 2010. © 2009 Wiley‐Liss, Inc.     

氨茶碱,环磷酸泉苷葡甲胺（MCA）对兔膈肌功能的影响

目的：观察氨茶碱、环磷酸腺苷葡甲胺对兔跨膈压及膈肌电活动的影响,以中肌疲劳的治疗效果提供实难依据。方法：刺激双侧膈神经４０ｍｉｎ复制膈肌疲劳（ＤｉＦ）动物模型,动物随机分三组（ｎ＝６）：氨茶碱组（１０ｍｇ／ｋｇ）、ＭＣＡ组（１０ｍｇ／ｋｇ）,合用组（氨茶碱１０ｍｇ／ｋｇ＋葡甲胺ｃＡＭＰ（１０ｍｇ／ｋｇ）。于ＤｉＦ前、ＤｉＦ及给药后３０、６０ｍｉｎ记录中压（Ｐｄｉ）;记录膈肌肌电图（ＥＭＧｄｉ）并输     

串脉冲致兔隔肌疲劳的动物模型

本实验采用串脉冲刺激兔隔神经法复制了家兔膈肌疲劳模型。测定隔肌张力（Ｔｄｉ）、跨膈压（Ｐｄｉ）及其频率特性（Ｔｄｉ－Ｆ、Ｐｄｉ－Ｆ）、呼吸流速（Ｖ）、肺阻力（ＲＬ）、膈肌肌电图（ＥＭＧｄｉ等作为评价膈肌收缩力量的指标。结果发现：经串脉冲刺激后,Ｐｄｉ－Ｆ曲线在３０、５０和１００Ｈｚ时显著降低,Ｐｄｉ、Ｔｄｉ、Ｖ和跨肺压均显著下降。氨茶碱可增加隔肌收缩力,延缓膈肌疲劳过程。结果提示,用串脉冲刺激兔膈神经法建立的模型是一种灵敏、可靠和稳定的膈肌疲劳动物模型。     

经会阴三维超声评价不同分娩方式初产妇肛门括约肌复合体和盆膈裂孔的临床应用价值

摘要 目的：探讨经会阴三维超声在不同分娩方式初产妇肛门括约肌复合体（ASC）和盆膈裂孔（PH）影响的评估价值。方法：选择2017年1月～2019年12月我院进行分娩的初产妇150例,按照分娩方式分成阴道分娩组71例,剖宫产组79例,比较两组基线资料。对所有受试者均实施经会阴三维超声检查,比较两组缩肛动作下肛门内括约肌（IAS）远端、中端及远端平面厚度,肛门外括约肌（EAS）远端平面及耻骨直肠肌（PRM）中端平面厚度,分娩前、产后6周、产后3个月PH左右径、PH前后径以及PH面积。结果：两组孕妇年龄、孕周及体质指数比较无差异（P＞0.05）,阴道分娩组IAS近端6点钟方向、12点钟方向平面厚度以及IAS中端、12点钟方向平面厚度均小于剖宫产组（P＜0.05）。阴道分娩组EAS远端12点钟方向平面厚度小于剖宫产组（P＜0.05）。阴道分娩组产后6周的PH左右径大于剖宫产组（P＜0.05）。阴道分娩组产后6周的PH前后径大于剖宫产组（P＜0.05）。阴道分娩组产后6周的pH面积大于剖宫产组（P＜0.05）。结论：经会阴三维超声可有效评估初产妇ASC和PH的影响情况,分娩会对初产妇ASC和PH产生影响,阴道分娩的初产妇产后存在明显的ASC厚度减小和PH增大现象。