Spatial transcriptomics reveals gene interactions and signaling pathway dynamics in rat embryos with anorectal malformation

Anorectal malformation (ARM) is a prevalent early pregnancy digestive tract anomaly. The intricate anatomy of the embryonic cloaca region makes it challenging for traditional high-throughput sequencing methods to capture location-specific information. Spatial transcriptomics was used to sequence libraries of frozen sections from embryonic rats at gestational days (GD) 14 to 16, covering both normal and ARM cases. Bioinformatics analyses and predictions were performed using methods such as WGCNA, GSEA, and PROGENy. Immunofluorescence staining was used to verify gene expression levels. Gene expression data was obtained with anatomical annotations of clusters, focusing on the cloaca region's location-specific traits. WGCNA revealed gene modules linked to normal and ARM cloacal anatomy development, with cooperation between modules on GD14 and GD15. Differential gene expression profiles and functional enrichment were presented. Notably, protein levels of Pcsk9, Hmgb2, and Sod1 were found to be downregulated in the GD15 ARM hindgut. The PROGENy algorithm predicted the activity and interplay of common signaling pathways in embryonic sections, highlighting their synergistic and complementary effects. A competing endogenous RNA (ceRNA) regulatory network was constructed from whole transcriptome data. Spatial transcriptomics provided location-specific cloaca region gene expression. Diverse bioinformatics analyses deepened our understanding of ARM's molecular interactions, guiding future research and providing insights into gene regulation in ARM development.

[Real-time localization for port-implanted catheter tip by echocardiographic guidance]

The clinical data of 23 patients undergoing real-time echocardiography-guided infusion port implantation in the Breast Center of Tsinghua Changgung Hospital in Beijing from January to July 2021 were analyzed. The length of catheter insertion L1 was initially estimated using surface measurement method in all patients. Intraoperatively, transthoracic echocardiography was applied using the parasternal four-chamber view to visualize the catheter image within the right atrium, and the length of catheter insertion L2 was recorded under the guidance of echocardiography. Postoperatively, chest radiographs were taken in the upright position to observe the position of the catheter tip. According to chest CT scans, the ideal length (L) for catheter tip placement was calculated when it was located at the junction of superior vena cava and right atrium. Bland-Altman scatter plot analysis and linear regression fitting test were used on L1 and L2 respectively with L to evaluate the consistency. A total of 23 patients were included in this study, among which one case of left breast cancer patient undergoing breast-conserving surgery had difficulty in identifying the catheter tip position due to residual pleural effusion obscuring the imaging of the cardiac apex four-chamber view. In 22 patients, the results of intraoperative ultrasound imaging were good, including 1 case of catheter ectopic to azygos vein, and 21 cases of right atrial catheter could be detected by ultrasound. Statistical analysis showed that there was a good consistency between L1 and L, L2 and L, and the difference between them was d=0.28 cm (95%CI:-1.76-2.31 cm) and d=0.20 cm(95%CI:-0.84-1.23 cm), respectively, with no statistical significance (P>0.05). In the linear regression model, L2 and L had a higher fit than L1, and the difference was statistically significant (R²=0.954, P<0.001). This study found that real-time echocardiographic localization technique can be applied in adult port surgery to replace X-ray-guided real-time catheter tip detection and adjustment to the optimal position.

Rack1-mediated ferroptosis affects hindgut development in rats with anorectal malformations: Spatial transcriptome insights

Anorectal malformation (ARM), a common congenital anomaly of the digestive tract, is a result of insufficient elongation of the urorectal septum. The cytoplasmic protein Receptor of Activated C-Kinase 1 (Rack1) is involved in embryonic neural development; however, its role in embryonic digestive tract development and ARM formation is unexplored. Our study explored the hindgut development and cell death mechanisms in ARM-affected rats using spatial transcriptome analysis. We induced ARM in rats by administering ethylenethiourea via gavage on gestational day (GD) 10. On GDs 14-16, embryos from both normal and ARM groups underwent spatial transcriptome sequencing, which identified key genes and signalling pathways. Rack1 exhibited significant interactions among differentially expressed genes on GDs 15 and 16. Reduced Rack1 expression in the ARM-affected hindgut, verified by Rack1 silencing in intestinal epithelial cells, led to increased P38 phosphorylation and activation of the MAPK signalling pathway. The suppression of this pathway downregulated Nqo1 and Gpx4 expression, resulting in elevated intracellular levels of ferrous ions, reactive oxygen species (ROS) and lipid peroxides. Downregulation of Gpx4 expression in the ARM hindgut, coupled with Rack1 co-localisation and consistent mitochondrial morphology, indicated ferroptosis. In summary, Rack1, acting as a hub gene, modulates ferrous ions, lipid peroxides, and ROS via the P38-MAPK/Nqo1/Gpx4 axis. This modulation induces ferroptosis in intestinal epithelial cells, potentially influencing hindgut development during ARM onset.

Diagnosis and management of fecal incontinence in children and adolescents

Fecal incontinence (FI) is a commonly occurring disease of high concern. It is characterized by voluntary and involuntary defecation in children and adolescents. It is not only a physical disease but also a psychological and behavioral disorder. FI poses a serious burden on individuals and their families and therefore has become a social problem. Unfortunately, the management of FI among children is still a challenge because the etiology varies widely. Constipation has been found to be the most common cause, while sphincter dysfunction and neurogenic abnormalities may also play a role. Currently, no consensus guidelines exist, and the criteria for selecting optional methods remain unclear. It is therefore necessary to improve the efficacy of diagnosis and management strategies of FI in children. This review focused on the classification and etiology, discussed the diagnosis and management methods of FI in children and adolescents, and aimed to guide future studies.

miR-322 treatment rescues cell apoptosis and neural tube defect formation through silencing NADPH oxidase 4

AIMS

Failure of neural tube closure resulting from excessive apoptosis leads to neural tube defects (NTDs). NADPH oxidase 4 (NOX4) is a critical mediator of cell growth and death, yet its role in NTDs has never been characterized. NOX4 is a potential target of miR-322, and we have previously demonstrated that miR-322 was involved in high glucose-induced NTDs. In this study, we investigated the effect of NOX4 on the embryonic neuroepithelium in NTDs and reveal a new regulatory mechanism for miR-322 that disrupts neurulation by ameliorating cell apoptosis.

METHODS

All-trans-retinoic acid (ATRA)-induced mouse model was utilized to study NTDs. RNA pull-down and dual-luciferase reporter assays were used to confirm the interaction between NOX4 and miR-322. In mouse neural stem cells and whole-embryo culture, Western blot and TUNEL were carried out to investigate the effects of miR-322 and NOX4 on neuroepithelium apoptosis in NTD formation.

RESULTS

NOX4, as a novel target of miR-322, was upregulated in ATRA-induced mouse model of NTDs. In mouse neural stem cells, the expression of NOX4 was inhibited by miR-322; still further, NOX4-triggered apoptosis was also suppressed by miR-322. Moreover, in whole-embryo culture, injection of the miR-322 mimic into the amniotic cavity attenuated cell apoptosis in NTD formation by silencing NOX4.

CONCLUSION

miR-322/NOX4 plays a crucial role in apoptosis-induced NTD formation, which may provide a new understanding of the mechanism of embryonic NTDs and a basis for potential therapeutic target against NTDs.

A torque type full tensor gravity gradiometer based on a flexure-strip suspension

Full tensor gravity gradiometers based on accelerometer pair combination are widely employed in earth resource explorations using gravity gradient measurements. However, the extremely high requirements of accelerometer dynamic range and the scale factor consistency of accelerometer pairs are the two main limitations to further improve their performances. In order to overcome these two extreme challenges, the torque type gravity gradiometer based on the Etövös torsion balance pendulum is re-considered. In this paper, an improved torque type full tensor gravity gradiometer with a flexure-strip suspension is proposed, which balances the mechanical sensitivity and the response time. The proposed gradiometer can be used to measure the full tensor gravity gradient by observing angle variations at three azimuths. The principle and feasibility of the torque type full tensor gravity gradiometer based on a flexure-strip suspension are introduced, and the main noise sources including mechanical thermal noise, position sensing noise, and readout noise are analyzed. A prototype gravity gradiometer with a designed resolution of 2 E/Hz^1/2 at 0.1 Hz is constructed (1 E = 10^-9/s²), and the experimental results indicate that its resolution comes to 3 E/Hz^1/2 at 0.1 Hz, which is mainly limited by the seismic noise. This type of gravity gradiometer can be further improved due to its high potential resolution and independence of matching combination requirement, which allows it to be applied in next generation gravity resource exploration.

Gastroesophageal Reflux Poses a Potential Risk for Late Complications of Bronchopulmonary Dysplasia: A Prospective Cohort Study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common respiratory disorder in extremely low birth weight infants. Although most symptoms of BPD improve, some late complications exist, even with regular treatment. Gastroesophageal reflux (GER), also common in extremely premature infants, may be related to many cardiorespiratory symptoms. However, the potential of GER as a risk factor for late complications associated with BPD is still unclear.

RESEARCH QUESTION

The goal of this study was to determine if GER increases the risk of late complications of BPD in infants.

STUDY DESIGN AND METHODS

A multicenter prospective cohort of 131 infants (79 male subjects, 52 female subjects) with BPD was enrolled. The development of late complications was assessed over an 18-month follow-up period. Twenty-four-hour pH-multichannel intraluminal impedance and gastric sodium concentrations were analyzed in all infants at 36 weeks' postmenstrual age and at the last interview. Prevalence and risk factors of late complications of BPD were analyzed by using forward logistic regression.

RESULTS

The prevalence of late complications in BPD infants was 63.79% and included respiratory symptoms (49.14%), vomiting (38.79%), retinopathy of prematurity (25.86%), hypoxic-ischemic injury (3.45%), rehospitalization (26.72%), and sudden death (0.86%). Respiratory diseases constituted the most frequent complication. The prevalence of GER in BPD was 42.24% and included acid GER (18.10%) and duodenogastroesophageal reflux (DGER; 24.14%). Risk factors for respiratory symptoms were gestational age ≤ 30 weeks (OR, 3.213; 95% CI, 1.221-8.460), birth weight < 1,500 g (OR, 2.803; 95% CI, 1.014-7.749), invasive ventilation > 7 days (OR, 4.952; 95% CI, 1.508-16.267), acid GER (OR, 4.630; 95% CI, 1.305-16.420), and DGER (OR, 5.588; 95% CI, 1.770-17.648). Infants with BPD and DGER were more prone to late complications than those with acid GER or no reflux.

INTERPRETATION

The prevalence of late complications is high in infants with BPD. GER (and in particular, DGER) poses a tentative risk for these late complications.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03014453; URL: www.clinicaltrials.gov.

Mesenteric heterotopic pancreas in a pediatric patient: A case report and review of literature

Heterotopic pancreas (HP) is a congenital anomaly defined as pancreatic tissue that has no contact with the orthotopic pancreas and its own duct system and vascular supply. The most common locations of HP are the upper gastrointestinal tract, specifically, the stomach, duodenum, and proximal jejunum. Involvement of the mesentery is rare. Here, we describe a rare case of mesenteric heterotopic pancreas (MHP) in a 12-year-old girl who presented with acute abdomen. The patient underwent emergency laparotomy, and the mass and adjacent small bowel were resected. Results of the postoperative histopathologic examination confirmed the diagnosis of MHP. Observation of the patient for 12 mo postoperatively showed no evidence of recurrence. Preoperative diagnosis of HP is difficult, even in a symptomatic patient. Increased awareness and understanding of the image characteristics of MHP will aid in correct preoperative diagnosis and appropriate patient management.

FOXD3/FOXD4 is required for the development of hindgut in the rat model of anorectal malformation

Congenital anorectal malformation is the most common digestive tract malformation in newborns. It has been reported that FOXD3/FOXD4, a forkhead transcription factor, regulates the generation, migration, and differentiation of neural crest cells. However, whether FOXD3/FOXD4 takes part in anorectal malformation remains unclear. In the present study, we used ethylene thiourea to induce the animal models of anorectal malformation in rat embryos and to interrogate the role of FOXD3/FOXD4 in anorectal malformation pathogenesis. Hindgut samples of the animal models were collected at E15, E17, E19, and E21 days of age. The expression of FOXD3/FOXD4 was detected by immunohistochemistry, western blot, and quantitative real-time fluorescence PCR. By immunohistochemical staining, FOXD3/FOXD4 was observed in epithelial cells of the rectum and the anus both in normal and rat embryos with anorectal malformation. Expression level analysis by western blot indicated that FOXD3/FOXD4 expression increased in ethylene thiourea-induced anorectal malformation groups. mRNA expression as determined by quantitative real-time fluorescence PCR analysis was consistent with the western blot results. Tentative conclusions were drawn that FOXD3/FOXD4 is expressed in the hindgut in rat embryos and is upregulated in anorectal malformation. FOXD3/FOXD4 is required for the development of the hindgut, and its aberrant expression may be an important factor leading to the incidence of anorectal malformation. Impact statement Congenital anorectal malformation (ARM) is the most common digestive tract malformation in newborns. The pathophysiological ground remains unclear. In this study, we used animal models of ARM for the first time to interrogate the role of FOXD3/FOXD4 in ARM pathogenesis. The animal models of ARM were successfully induced by ethylene thiourea (ETU) in rat embryos providing a strong basis for pathogenesis study of this disease. Expression analysis of FOXD3/FOXD4 was carried out in these models, and the results shape a deeper understanding of FOXD3/FOXD4 being required for the normal development of the hindgut. The aberrant expression of FOXD3/FOXD4 may be an important factor leading to ARM incidence.

[The role and significance of digital reconstruction technique in liver segments based on portal vein structure]

Objective: To study the segment of liver according to the large amount of three-dimensional(3D) reconstructive images of normal human livers and the vascular system, and to recognize the basic functional liver unit based on the anatomic features of the intrahepatic portal veins. Methods: The enhanced CT primitive DICOM files of 1 260 normal human livers from different age groups who treated from October 2013 to February 2017 provided by 16 hospitals were analyzed using the computer-aided surgery system.The 3D liver and liver vascular system were reconstructed, and the digital liver 3D model was established.The vascular morphology, anatomical features, and anatomical distributions of intrahepatic portal veins were statistically analyzed. Results: The digital liver model obtained from the 3D reconstruction of CAS displayed clear intrahepatic portal vein vessels of level four.Perform a digital liver segments study based on the analysis of level four vascular distribution areas.As the less anatomical variation of left hepatic portal vein, the liver was classified into four types of liver segmentation mainly based on right hepatic portal vein.Type A was similar to Couinaud or Cho's segmentation, containing 8 segments(537 cases, 42.62%). Type B contained 9 segments as there are three ramifications of right-anterior portal vein(464 cases, 36.82%). The main difference for Type C was the variation of right-posterior portal vein which was sector shape(102 cases, 8.10%). Type D contained the cases with special portal vein variations, which needs three-dimensional simulation to design individualized liver resection plan(157 cases, 12.46%). These results showed that there was no significant difference in liver segmental typing between genders(χ(2)=2.179, P=0.536) and did not reveal any significant difference in liver segmental typing among the different age groups(χ(2)=0.357, P=0.949). Conclusions: The 3D digital liver model can demonstrate the true 3D anatomical structures, and its spatial vascular variations.The observation of anatomic features, distribution areas of intrahepatic portal veins and individualized liver segmentation achieved via digital medical 3D visualization technology is of great value for understand the complexity of liver anatomy and to guide the precise hepatectomy.

[Gene Analysis for the Sudden Death of Hypertrophic Cardiomyopathy by Whole Exome Sequencing.]

OBJECTIVES

To analyze the related pathogenicity gene mutations in a sudden death of hypertrophic cardiomyopathy （HCM） on whole exome level.

METHODS

Whole exome sequencing （WES） was been performed on a sudden death case sample with pathological features of HCM by Illumina® Hiseq 2500 platform. Using hg19 as the reference sequences, the sequencing data were analyzed. Suspicious single nucleotide variants （SNV） were screened, and the conservatism and function were analyzed by the software such as PhyloP, PolyPhen-2, SIFT, etc.

RESULTS

After screening, a heterozygous mutation C719R was finally identified in the gene MYBPC3 of this case.

CONCLUSIONS

The molecular anatomy on whole exome level by second generation sequencing technology can help to define the molecular mechanism of HCM and provide a new mothed and thought for analysis of death cause.

Temporal and spatial expression of caudal-type homeobox proteins in the midgut of human embryos

BACKGROUND

This study aimed to determine the spatiotemporal expression of caudal-type homeobox genes (CDX1, CDX2 and CDX4) during development of the midgut in human embryos and to explore the possible roles of CDX genes during the morphogenesis of human midgut. Human embryos (n=28) were sectioned serially and sagittally and CDX1, CDX2 and CDX4 proteins were detected on the midline from the 5th to 9th weeks of gestation by immunohistochemical staining.

RESULTS

CDX1, CDX2 and CDX4 proteins were weakly expressed in epithelium and mesenchyme of the midgut in the 6th and 7th weeks of gestation and reached estimated optimal level on the 8th and 9th weeks of gestation. In the 9th week of gestation, immunoreactivities specific to CDX1, CDX2 and CDX4 were restricted in epithelium of the midgut.

CONCLUSIONS

CDX1, CDX2 and CDX4 proteins began to express in human midgut in the 6th week of gestation. From the 6th to 9th week of gastation, the expression of CDX1, CDX2 and CDX4 proteins gradually increase and exhibited overlapping expression patterns, suggesting that CDX genes may be involved in early development of the epithelium of human midgut. Cross-regulatory interactions may exist among CDX genes with respect to human midgut development.

Spatiotemporal expression of BMP7 in the development of anorectal malformations in fetal rats

The aim of this study was to determine the expression patterns of bone morphogenetic protein 7 (BMP7) during anorectal development in normal rat embryos and in embryos with anorectal malformations (ARM), and to investigate the possible role of BMP7 in the pathogenesis of ARM. ARM was induced by treating rat embryos with ethylenethiourea on the 10th gestational day (GD10). Embryos were harvested by Cesarean delivery and the spatiotemporal expression of BMP7 was evaluated in normal (n=168) and ARM embryos (n=171) from GD13 to GD16 using immunohistochemistry staining and western blot analysis. Immunohistochemical staining in normal embryos revealed that BMP7 was abundantly expressed on the epithelium of the urorectal septum (URS) and the hindgut on GD13, and BMP7-immunopositive cells were extensively detected in the URS, hindgut, and cloacal membrane by GD14. Increased positive tissue staining was noted on the fused tissue of the URS and the thin anal membrane on GD15. In ARM embryos, the epithelium of the cloaca, URS, and anorectum were negatively or only faintly immunostained for BMP7. BMP7 protein expression showed time-dependent changes in the developing hindgut according to western blotting, and reached a peak on GD15 during anus formation. BMP7 expression levels from GD14 to GD15 were significantly lower in the ARM group compared with the normal group (P<0.05). Spatiotemporal expression of BMP7 was disrupted in ARM embryos during anorectal morphogenesis from GD13 to GD16. These results suggest that downregulation of BMP7 at the time of cloacal separation into the primitive rectum and UGS might be related to the development of ARM.

Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

Dynamic expression of molecules that control limb muscle development including Fhl1 in hind limbs of different gestational age

Muscle abnormality could be a key reason for congenital clubfoot (CCF) deformity, which manifests itself during fetal development. FHL1 down-regulated expression is involved in the formation of skeletal muscle abnormalities in CCF and FHL1 gene mutations contribute to the development of some kinds of myopathies. Therefore, detecting dynamic expression of Fhl1 and other molecules (Hgf, MyoD1, Myogenin, and Myh4) that control limb muscle development in hind limbs of different gestational age will provide a foundation for further research on the molecular mechanism involves in the myopathies or CCF. The dynamic gene expression levels of Fhl1, Hgf, MyoD1, Myogenin, and Myh4 in the lower limbs of E16, E17, E19, and E20 rat embryos were examined by real-time RT-PCR. Immunofluorescence was used to detect formation of specific muscle fibers (fast or slow fibers) in distal E17 hind limbs. The expression levels of Fhl1, Hgf, MyoD1, Myogenin, and Myh4 were varying in hind limbs of different gestational age. Real-time PCR results showed that all the genes that control skeletal muscle development except for Fhl1 exhibited a peak in E17 lower limbs. Immunofluorescence results showed obviously positive fast-myosin in the distal E17 lower limbs and meanwhile slow-myosin had no apparently signals. E17 was a critical time point for terminal skeletal muscle differentiation in the lower limbs of rat embryos.

Design and validation of a high-voltage levitation circuit for electrostatic accelerometers

A simple high-voltage circuit with a voltage range of 0 to 900 V and an open-loop bandwidth of 11 kHz is realized by using an operational amplifier and a MOSFET combination. The circuit is used for the levitation of a test mass of 71 g, suspended below the top-electrodes with a gap distance of 57 μm, so that the performance of an electrostatic accelerometer can be tested on the ground. The translation noise of the accelerometer, limited by seismic noise, is about 4 × 10(-8) m/s(2)/Hz(1/2) at 0.1 Hz, while the high-voltage coupling noise is one-order of magnitude lower.

Ultrasonographic dimensions of the common bile duct in Chinese children: results of 343 cases

BACKGROUND

At present, the diagnostic criteria of congenital cholangiectasis are still vague.

PURPOSE

The aim of this study was to assess the diameter references of the common bile duct (CBD) in pediatric population in different age groups with ultrasound.

METHODS

The diameter of the common bile duct was measured with ultrasound in 343 Chinese Han children aged 1 day to 14 years (mean: 3.2 years, median: 2.8 years) who were all free of hepatic and biliary tract disease. The ultrasound records, gender, and age were collected for reviewed analysis.

RESULTS

A total of 343 children were included, and the CBD was clearly detected in 322 cases (93.9%). The mean diameter of this population was 1.58 ± 0.70 mm. (ranging from 0.4 to 4.4mm). Spearman correlation analysis showed that the diameter of CBD was positively associated with age (r=0.573, P<0.001). The percentile method demonstrated that the diameter references of CBD was as follows: ≤ 1 years: ≤ 2.26 mm; ≤ 4 years: ≤ 2.99 mm; ≤ 7 years: ≤ 3.03 mm; and ≤ 14 years: ≤ 4.10mm.

CONCLUSIONS

There was a close correlation between CBD width and the age. The range of CBD widths in each age group will be helpful in the diagnosis of biliary dilatation in childhood.

Nonoperative management of appendiceal phlegmon or abscess with an appendicolith in children

BACKGROUND

The optimal treatment of appendiceal phlegmon or abscess with an appendicolith is controversial. This study aimed to evaluate outcomes and prognosis of nonoperative management of appendiceal phlegmon or abscess with an appendicolith in children.

METHODS

From 2007 to 2011, 105 children with appendiceal phlegmon or abscess who were treated nonoperatively without interval appendectomy were reviewed. Average follow-up of subjects was 2.4 years. Data were compared between subjects with and without an appendicolith or persistent presence and disappearance of an appendicolith.

RESULTS

The success rate for nonoperative therapy for appendiceal phlegmon or abscess with appendicolith was 95.9 %. The risk of recurrent appendicitis in appendiceal phlegmon or abscess with appendicolith (19.1 %) was higher than that without appendicolith (8.9 %, P = 0.132). The rate of appendicolith disappearance during follow-up was 80.9 %. The persistent presence of an appendicolith was associated with a significantly higher recurrence rate (66.7 %) compared with appendicolith disappearance (7.9 %, P < 0.05).

CONCLUSION

Appendiceal phlegmon or abscess with an appendicolith can be managed nonoperatively, and most appendicoliths can be resolved. Persistent presence of an appendicolith is a significant risk factor for recurrent appendicitis. Interval appendectomy is recommended for persistent presence of appendicolith, but is not indicated in cases without appendicolith or appendicolith disappearance.

High resolution space quartz-flexure accelerometer based on capacitive sensing and electrostatic control technology

High precision accelerometer plays an important role in space scientific and technical applications. A quartz-flexure accelerometer operating in low frequency range, having a resolution of better than 1 ng/Hz(1/2), has been designed based on advanced capacitive sensing and electrostatic control technologies. A high precision capacitance displacement transducer with a resolution of better than 2 × 10(-6) pF/Hz(1/2) above 0.1 Hz, is used to measure the motion of the proof mass, and the mechanical stiffness of the spring oscillator is compensated by adjusting the voltage between the proof mass and the electrodes to induce a proper negative electrostatic stiffness, which increases the mechanical sensitivity and also suppresses the position measurement noise down to 3 × 10(-10) g/Hz(1/2) at 0.1 Hz. A high resolution analog-to-digital converter is used to directly readout the feedback voltage applied on the electrodes in order to suppress the action noise to 4 × 10(-10) g/Hz(1/2) at 0.1 Hz. A prototype of the quartz-flexure accelerometer has been developed and tested, and the preliminary experimental result shows that its resolution comes to about 8 ng/Hz(1/2) at 0.1 Hz, which is mainly limited by its mechanical thermal noise due to low quality factor.

Sonographic diagnosis of juvenile polyps in children

The aim of this study was to assess the diagnostic value of ultrasonography for juvenile polyps in children and their sonographic characteristics. A retrospective analysis was performed of the ultrasound findings in 27 children who were diagnosed preoperatively with juvenile polyp within the intestinal tract by ultrasonography and then confirmed by colonoscopy, laparotomy and histopathology. The ultrasonic finding common to all polyps was an isolated intraluminal nodular or massive protrusion, associated with multiple mesh-like fluid areas of different sizes. In 25 children, surrounding pedicle-like low echoes of varying lengths were seen connecting with the polyps to form "mushroom" sign. The color Doppler showed abundant blood flow signals within all polyps and pedicles in a shape of a branch or an umbrella. For seven children with an intussusception, the polyp shadow was detected in the cervical part or interior of the intussusception. Ultrasonography is, thus, considered to be a feasible method for diagnosing intestinal juvenile polyp.

[Expression of Wnt5a in the terminal rectum of children with anorectal malformation]

OBJECTIVE

To study the expression of Wnt5a protein in the terminal rectum of children with anorectal malformation (ARM) and the possible association between Wnt5a and ARM.

METHODS

Specimens were obtained from 20 children with ARM, 7 children with acquired rectovestibular fistula and 6 children with non-gastrointestinal tract disease (control group). The expression of Wnt5a protein in the terminal rectum was determined by immunohistochemistry and Western blot.

RESULTS

Wnt5a was mainly expressed in the rectum of the myenteric nerve plexus, mucosal layer and submucosa in the control group. Compared with the control group, Wnt5a expression in the terminal rectum decreased significantly in the ARM group, and decreased more significantly in children with high ARM. The results of Western blot showed the expression of Wnt5a protein in the high, intermediate and low ARM groups were significantly lower than that in the acquired rectovestibular fistula and the control groups (P<0.01). The expression of Wnt5a protein in the high and the intermediate ARM groups were also lower than that in the low ARM group (P<0.01). There was no significant difference in the Wnt5a protein expression between the acquired rectovestibular fistula and the control groups.

CONCLUSIONS

The expression of Wnt5a in the termina1 rectum decreases in children with ARM, suggesting Wnt5a may play an important role in the development of ARM.

Embryonic development of the internal anal sphincter in rats with anorectal malformations

BACKGROUND/PURPOSE

The embryogenesis of the internal anal sphincter (IAS) in anorectal malformations (ARMs) remains unclear. This study aimed to investigate the development of the smooth muscle in the terminus of the digestive tract in normal and abnormal rats.

METHODS

Rat embryos with ARMs were generated by administration of ethylenethiourea to pregnant rats. The normal rat embryos and embryos with ARMs from E13.5 to E21 were serially sectioned in the sagittal plane and stained immunohistochemically using specific antibody to α-smooth muscle actin (SMA). Temporospatial study was carried out on circular muscle of the distal portion of the hindgut.

RESULTS

α-Smooth muscle actin immunolabeling cells could not be observed in the hindgut on E13.5, E14, and E14.5. On E15, there were α-SMA immunolabeling circular muscle cells in the hindgut; and the distal portion of the circular muscle was not thickened in the normal and ARMs rats. From E16 onward, the smooth muscle with slight dilated terminus, which was characterized by the features of IAS, could be noted in the primitive anorectum. In the normal group, the circular muscle in the distal portion of the hindgut thickened slightly and became the musculature with shutter-like bundles. In the ARMs group, the α-SMA immunolabeling myogenic precursors of the smooth muscle could be observed in the primitive anorectum as well. The musculature was similar to that in the normal group. On E15 and E16, there was no significant difference in the development of the circular muscle in the 2 groups. Moreover, the terminus of the circular muscle in the hindgut did not reach the orificium fistulae in ARMs rats. From E17 onward, in ARMs rats, the funnel-shaped distal hindgut communicated the genitourinary tract with a narrow fistula; the dilated musculature at this portion thinned gradually and formed an acute angled extremity in the ARMs group rather than formed blunt extremity in the normal group; the terminus circular muscle in the dorsal hindgut reached the orificium fistulae. During the following gestational days, the circular muscle of the hindgut in both normal and ARMs rats continued its own tendency.

CONCLUSION

The IAS primordium started to appear at the terminus of the hindgut on E15 in the 2 groups. The IAS in the ARMs group failed to develop as well as that in the normal group. The IAS dysplasia occurred in the late embryonic development (E17-E21).

Cell apoptosis during the cloacal embryonic development in rats with anorectal malformations

OBJECTIVE

In the normal embryonic development of anorectum, apoptosis plays an important role. To explore the role of apoptosis in anorectal malformations (ARM), this study investigated cell apoptosis during the cloacal embryonic development in ARM embryos.

METHODS

ARM embryos were induced by intragastric administration of ethylenethiourea (125 mg/kg) for pregnant rats on embryonic day 10 (E10). The distribution of apoptotic cells in the cloaca was ascertained by hematoxylin and eosin and TUNEL staining in the normal control embryos (n=102) and ARM embryos (n=147) on E13, E13.5, E14, E15 and E16.

RESULTS

On E13, apoptotic cells were detected in the urorectal septum of rat embryos in the control group. With the development of embryos, the number of apoptotic cells in the mesenchyme of urorectal septum gradually increased and a large number of apoptotic cells were seen in the dorsal rectal mesenchyme. On E14, apoptotic cells appeared at the terminal rectum and the dorsal cloacal membrane. On E15, the urorectal septum fused with the cloacal membrane and apoptotic cells in the urorectal septum mesenchyme continuously extended down to the fusion region. Compared with the control group, apoptotic cells in the urorectal septum, the dorsal rectal mesenchyme and the cloacal membrane of the ARM rat embryos were significantly reduced during the embryonic development. The development of the urorectal septum was delayed and it did not fuse with the cloacal membrane in ARM embryos.

CONCLUSIONS

During the embryonic development of cloaca, abnormal apoptosis in the urorectal septum, the dorsal rectal mesenchyme and the cloacal membrane may be one of the reasons for anorectal malformations. The proper regulation of cell apoptosis may be one of the key mechanisms for normal development of anorectum in the embryonic stage.

Expression of EphB2 in the development of anorectal malformations in fetal rats

PURPOSE

The receptor tyrosine kinase of the Eph family is a large group of highly conserved molecules that function in diverse intercellular recognition events. It has been reported that EphB2 is related to caudal remodeling events. The aim of this study is to investigate EphB2 expression in anorectal development in normal and rat embryos with anorectal malformations (ARMs) and attempt to define its role in anorectal morphogenesis.

METHODS

The ethylenethiourea (ETU) rat model of the ARMs was used in this study. Immunohistochemical analyses and real time quantitative polymerase chain reaction (PCR) were carried out to investigate EphB2 protein localizations and messenger RNA (mRNA) expression levels. (1) Rat embryos with ARMs were obtained by treating pregnant rats (n = 24) with administration of ETU on gestation day (Gd) 10. Normal rat embryos (n = 111) and embryos treated by ETU without ARMs (n = 90) were the control groups, and embryos with ARMs (n = 108) from Gd13 to Gd16 were divided according to the sections taken from specimens. (2) Embryos were sequentially sectioned in the sagittal and transversal planes before staining with a specific antibody to EphB2. Spatiotemporal study was carried out on EphB2 expression. (3) Individual frozen sections were used to manually microdissect the cloaca and anorectal specimens for total RNA extraction. EphB2 expression was evaluated by real time quantitative PCR.

RESULTS

On the immunologic labeling study, EphB2 expression was confined to the cloaca in control groups, whereas EphB2 expression was mainly located at the urorectal septum (URS) and cloacal membrane on Gd13 and Gd14. The increased positive expression was observed in the fused tissue of the URS and cloacal membrane on Gd15. On Gd16, the anal membrane broke down, and the rectum was able to be in contact with the anus, and EphB2 expression was then noted in mucous membrane of rectum. EphB2 expression was seen in the cloacal and anorectal tissues of embryos with ARMs. By integrated optical density (IOD) measurement, IOD value of EphB2 protein was significantly lower in the ARM group than that in the control groups on Gd13 to Gd16 (P < .05), respectively. As shown by real time quantitative PCR, EphB2 expression was detected in 3 groups. EphB2 mRNA level increased on Gd13 to Gd16 but gradually decreased after Gd16. The expression level of EphB2 mRNA in the ARM embryos was lower on Gd13 to Gd16 than that in control groups (P < .05).

CONCLUSIONS

EphB2 expression decreased in the ARM embryos and was confined to URS and cloaca, whereas it was higher in control group. Our data thus indicated that EphB2 molecules possibly contributed to the anorectal morphogenesis and the decreased expression of EphB2 might be related to the development of ARMs.

Long-term outcome, colonic motility, and sphincter performance after Swenson's procedure for Hirschsprung's disease: a single-center 2-decade experience with 346 cases

BACKGROUND

The aim of this study is to explore the long-term outcome and the colon and sphincter function in children undergoing the Swenson's operation for Hirschsprung's disease (HD).

METHODS

Three hundred forty-six children (266 males and 80 females) undergoing Swenson's operation for HD for 8 to 20 years were followed up. Barium enema and defecography, total and segmental colonic transit time with the simplified radioopaque markers, and the anorectal vector manometry were used.

RESULTS

Stooling patterns were fair in most patients, and the functional examinations were abnormal in few cases.

CONCLUSIONS

The long-term outcome is satisfactory in most of the children undergoing the Swenson's operation for HD, but it is still not as good as what the surgeons have expected. This is probably because of the abnormal colonic motility and/or the dysfunctions of the internal anal sphincter.

Evaluation of anorectal function after transanal one-stage endorectal pull through operation in children with Hirschsprung's disease

OBJECTIVE

The short-term efficacy of the transanal one-stage endorectal pull through operation for Hirschsprung's disease is satisfactory. However the long-term outcome of anorectal function has not been fully understood. The aim of this study was to evaluate the stooling pattern, colonic motility and anal sphincter performance after transanal one-stage pull through operation in children with Hirschsprung's disease.

METHODS

Fifty-eight children who underwent transanal one-stage pull through operation for Hirschsprung's disease were followed up. The mean follow-up duration was 15.8 months (range, 6-24 months). The stooling patterns of the patients were investigated by the informed questionnaire. Barium enema, defecography, total and segmental colonic transit time and the anorectal vector manometry were performed. Thirty- three healthy children were used as controls.

RESULTS

Most of patients had normal stool consistency and frequency. Postoperative enterocolitis occurred in 3 patients, and constipation was found in five patients. Postoperative soiling was observed in 9 patients. None of the 58 patients had incontinence, cuff infection, anastomotic leak and mortality. The barium enema showed that the configuration of the colon recovered well in most of patients. Postopertive defecography showed the anorectal angle of all the patients was open, fixed and bigger than that of preoperation and the healthy controls (P < 0.01). Postoperatively, the mean total gastrointestinal transit time (TGITT), the left colonic transit time (LCTT) and rectosigmoid colonic transit time (RSTT) in the 58 patients were significantly shorter than preoperatively (P < 0.01) and were similar to those of the control group. The rectoanal inhibitory reflex was regained in 5 patients. The anal maximal pressure of the patients with constipation in resting and squeezing condition were significantly higher than those of the asymptomatic patients and controls (P < 0.05). The vector volume (VV) and vector symmetric index (VSI) in patients with soiling were significantly lower than those in preoperation and the controls (P < 0.05). The VSI in the patients with constipation was significantly higher compared with the controls (P < 0.05).

CONCLUSIONS

The stooling function, colonic motility and anal sphincter performance manifest well in most of the patients after the transanal endorectal pull through operation for Hirschsprung's disease. Stooling disorders in few cases are probably related to decrease or disappearance of the sigmoid loops, dysfunction of the "neorectosigmoid", an open and fixed anorectal angle and achalasia of the internal anal sphincter.

Normal and abnormal embryonic development of the anorectum in rats

BACKGROUND

The embryologic and pathologic aspect of anorectal malformation (ARM) remains poorly understood. There is no universally accepted theory to explain anorectal embryology and the abnormal development that produces ARM. The aim of this study was to observe the developmental processes of anorectum in rats and to explore the abnormal embryonic development that leads to ARM.

METHODS

Rat embryos with ARM were obtained by treating pregnant rats with administration of ethylenethiourea (ETU). Normal rat embryos and embryos with ARM from gestational days 12.5 to 20 were sectioned serially and sagittally and stained with H & E. The relevant structure including cloaca and urorectal septum (URS) were examined in a temporospatial sequence.

RESULTS

Characteristics of anorectum development in ARM rat embryos treated by ETU were as follows: (1) URS never fused with cloaca membrane. (2) Dorsal cloacal membrane was maldeveloped. (3) Cloacal configuration was abnormal. (4) Tail groove never appeared. All type of ARM was the rectourethal fistula and common cloaca in ETU-treated rat embryos and was discernible on gestation day 16.

CONCLUSIONS

Absence of the tail groove and maldevelopment of the dorsal cloacal membrane, cloacal configuration, and urorectal septum are likely to be responsible for the formation of ARM. Failure of fusion of the URS with cloacal membrane is the immediate reason for rectourethral fistula or common cloaca in ETU-treated rats.

Long-term outcome and quality of life after the Swenson procedure for Hirschsprung's disease

BACKGROUND/PURPOSE

The aim of this study was to investigate long-term outcome and quality of life after the Swenson operation for rectosigmoid Hirschsprung's Disease (HD).

METHODS

Forty-five patients who underwent the Swenson procedure for HD underwent follow-up for 8 to 16 years. Long-term outcome and quality of life were assessed by interviews and questionnaires including scoring systems. Forty-four healthy children with similar age, sex, and education level distributions used as controls.

RESULTS

In 45 patients, 23 (51.1%) had bowel dysfunction. Seventeen patients (37.8%) suffered from fecal soiling. According to the clinical bowel function scoring system, the patients' scores (7.6 +/- 2.1) were significantly lower than those of the controls (11.4 +/- 0.6; P <.05). Because of poor fecal continence, 25 patients (55.7%) had to restrict their foods. School absence occurred in 6 (13.3%) patients. Seven patients (15.6%) had problems in peer relationships. According to the Quality-of-Life Scoring Criteria, 86.7% patients had good or fair quality of life. The patients' scores (7.7 +/- 2.9) were significantly lower than those of the controls (11.6 +/- 0.7; P <.05). And the scores of patients who had fecal soiling and incontinence (6.3 +/- 2.7) were significantly lower than those of patients without fecal soiling and incontinence (8.4 +/- 2.6; P <.05).

CONCLUSIONS

Although most patients had good or fair quality of life after surgical correction for HD, the long-term outcome and quality of life are not as good as surgeons expected. The bowel function and quality of life of the patients were poorer than those of healthy children. Fecal soiling is very common and affects patients' quality of life. Long-term regular follow-up is indispensable. Close attention should be paid to minimizing bowel dysfunction for patients with HD postoperatively to improve their quality of life.

[Selection of approach and understanding of application in deep Over-Bite cases treated by Edgewise technique]

There are many approaches to open deep over bite with edgewise technique.As far as the three clinical pictures of deep over-bite are concerned,this article indicates that the extrusion and intrusion of teeth should be treated differently according to the technique of malocclusion-forming.It also makes a preliminary exploratory and analyse on the selection of commonly used approaches and personal understanding of clinical application.