Effects of pterostigma structure on vibrational characteristics during flight of Asian ladybird Harmonia axyridis (Coleoptera: Coccinellidae)

The hind wings of beetles are deployable and play an essential role in flight. In the Asian ladybird Harmonia axyridis (Coleoptera: Coccinellidae), the pterostigma (pst) is found in the middle of the hind wing instead of at the tip of the hind wing. This paper investigates the effect of the pst on the vibrational characteristics during the flight of H. axyridis. Based on cross sections of the pst and veins as well as the morphology and nanomechanical properties of the hind wing, including the wing membrane and veins, three three-dimensional coupling models, Models I-III, of hind wings with/without pst structures and veins with varying or uniform reduced moduli are established. Modal analysis results for these three models show that the vibrational characteristics and deformation tendencies change the flight performance of the hind wing models with pst structures compared with that of the other models. The results in this paper reveal that the pst structure has an important influence on vibrational characteristics and deformation tendencies and, hence, on flight performance; the relationships between the body mass and the area of the hind wing, which have significant implications for the design of biomimetic deployable wing structures for micro air vehicles (MAVs), are also analyzed.

The application of human pluripotent stem cells to model the neuronal and glial components of neurodevelopmental disorders

Cellular models of neurodevelopmental disorders provide a valuable experimental system to uncover disease mechanisms and novel therapeutic strategies. The ability of induced pluripotent stem cells (iPSCs) to generate diverse brain cell types offers great potential to model several neurodevelopmental disorders. Further patient-derived iPSCs have the unique genetic and molecular signature of the affected individuals, which allows researchers to address limitations of transgenic behavioural models, as well as generate hypothesis-driven models to study disorder-relevant phenotypes at a cellular level. In this article, we review the extant literature that has used iPSC-based modelling to understand the neuronal and glial contributions to neurodevelopmental disorders including autism spectrum disorder (ASD), Rett syndrome, bipolar disorder (BP), and schizophrenia. For instance, several molecular candidates have been shown to influence cellular phenotypes in three-dimensional iPSC-based models of ASD patients. Delays in differentiation of astrocytes and morphological changes of neurons are associated with Rett syndrome. In the case of bipolar disorders and schizophrenia, patient-derived models helped to identify cellular phenotypes associated with neuronal deficits (e.g., excitability) and mutation-specific abnormalities in oligodendrocytes (e.g., CSPG4). Further we provide a critical review of the current limitations of this field and provide methodological suggestions to enhance future modelling efforts of neurodevelopmental disorders. Future developments in experimental design and methodology of disease modelling represent an exciting new avenue relevant to neurodevelopmental disorders.

479 When 2 rights make a wrong

Background

The presence of an intra-cardiac mass is always a cause for concern, with regards to not only aetiology, but also treatment of complications. We describe a case series of 2 right sided cardiac myxomas, where the first case described an unusual location for tumour occurrence, while the second case provided insights into complications of a cardiac myxoma.

Methods

The first case involved a 70 year old asymptomatic lady who was referred for an additional heart sound. A transthoracic echocardiogram (TTE) showed a large, mobile 1.5 X 1.2 cm mass, attached to the atrial surface of septal tricuspid valve leaflet, prolapsing in and out of the right sided chambers. This was confirmed on transoesophageal echocardiogram (TEE). Cardiac MRI (magnetic resonance imaging) showed a similar mass attached to the septal tricuspid leaflet with features consistent with a myxoma. She was referred to cardiothoracic surgery, and 2 lobulated tumours arising the septal tricuspid valve and adjacent posterior leaflet were seen. The tumours were resected and a bio-prosthetic tricuspid valve replacement implanted. Histology of the tumours showed myxomatous degeneration of tricuspid valve, consistent with cardiac myxoma.

The second case was a 56 year old lady who had dyspnoea, pedal oedema and an elevated jugular venous pulse on examination. A TTE done showed a large 7 X 4 cm mass extending from the right atrium (RA) into the right ventricle (RV). The left ventricular ejection fraction was 35%. Cardiac MRI confirmed the presence of a large mass in the right ventricle that exerted pressure effects on the ventricular septum and RV anterior free wall. Intra-operatively, a large RA mass attached by a stalk to the fossa ovalis was seen. The mass was excised and histology was consistent with cardiac myxoma. A repeat transthoracic echocardiogram done 2 weeks later showed normalisation of the LVEF.

See images below for more information.

Conclusion

While myxomas are the most common benign cardiac tumours, they occur less commonly in the right atrium, and much less so on the tricuspid valve. Clinical manifestations range from being completely asymptomatic, as in the 1st case, to non-specific constitutional symptoms such as fever or general malaise, and to life-threatening complications. These include embolism to the pulmonary circulation, causing sudden death, or to the systemic circulation through an intra-cardiac shunt, causing strokes. This risk is increased if the tumour is large, polypoidal and friable. Large tumours can also cause obstructive symptoms and heart failure. Thus timely diagnosis with multi-modality imaging tools, and definitive treatment with complete resection of the tumour are essential. Continued monitoring for recurrences of the tumour, which can occur in 1-5% of all cases, should be performed as well.

Abstract 479 Figure. Right sided cardiac masses

P1309 A jellyfish in the sea

Background

The unexpected presence of a left ventricular (LV) mass is always a cause of concern for physicians. This is especially so in the presence of a cerebrovascular accident and a recent cardiac event, where the hunt for a cardioembolic source begins. We describe a case of an unusual presentation of a LV thrombus masquerading as a cystic mass, where diagnosis was confirmed with multimodality imaging tools.

Purpose

A 58 year old Thai male first presented to the emergency department with left brachio-facial syndrome secondary to a right pre-central gyrus stroke. He had chest pain 2 days prior, and was pain free on admission. An electrocardiogram done showed an evolved anterior myocardial infarction.

Methods and Results

A transthoracic echocardiogram performed on the 4th day of admission revealed a mildly impaired left ventricular systolic function with an ejection fraction of 45%, and wall motion abnormalities in the left anterior descending artery territory. There was an apical gelatinous-like, cystic and mobile mass with soft flexible walls, measuring 2.4 X 2.1cm. Differentials at this point included cystic thrombus, hydatid cyst, capillary haemangioma and intracardiac tumour.

A cardiac MRI was performed which showed an irregular apical mass with features suggestive of fresh thrombus. The mass demonstrates hyperintensity T1-w FSE sequences (with and without fat sat), increased hyperintensity in T2-w triple IR FSE, with no increased uptake in first pass perfusion, T1-w post contrast, or early and late gadolinium enhancement images.

A repeat transthoracic echocardiogram done 11 days after anticoagulation showed a 50% reduction in the size of the mass.

See images below for more information.

Conclusion

In the era of early primary percutaneous coronary intervention and anticoagulation following an acute myocardial infarction (AMI), LV thrombus is an uncommon complication. It can occur within 2 weeks after an AMI, where increased blood stasis from dyskinesia or akinesia of associated wall segments, and a hypercoagulable state increases the risk of thrombus formation. A literature search has shown that presentation of the thrombus as a cystic mass is rare as well. As such, early diagnosis allowing for early treatment, especially when systemic embolism of thrombus is suspected, is important. Other causes of cystic LV thrombus do need to be considered in the relevant clinical context. These include infectious causes such as hydatid cyst, capillary hemangioma or intracardiac tumour, which are less likely given the history and investigation results. In this case, a trial of therapy with anticoagulation reduced the size of the cystic mass, and along with imaging findings, confirmed the diagnosis of a cystic LV thrombus.

Abstract P1309 Figure. TTE and MRI heart

The deubiquitinase USP7 stabilizes Maf proteins to promote myeloma cell survival

The Maf proteins, including c-Maf, MafA, and MafB, are critical transcription factors in myelomagenesis. Previous studies demonstrated that Maf proteins are processed by the ubiquitin-proteasome pathway, but the mechanisms remain elusive. This study applied MS to identify MafB ubiquitination-associated proteins and found that the ubiquitin-specific protease USP7 was present in the MafB interactome. Moreover, USP7 also interacted with c-Maf and MafA and blocked their polyubiquitination and degradation. Consistently, knockdown of USP7 resulted in Maf protein degradation along with increased polyubiquitination levels. The action of USP7 thus promoted Maf transcriptional activity as evidenced by luciferase assays and by the up-regulation of the expression of Maf-modulated genes. Furthermore, USP7 was up-regulated in myeloma cells, and it was negatively associated with the survival of myeloma patients. USP7 promoted myeloma cell survival, and when it was inhibited by its specific inhibitor P5091, myeloma cell lines underwent apoptosis. These results therefore demonstrated that USP7 is a deubiquitinase of Maf proteins and promotes MM cell survival in association with Maf stability. Given the significance of USP7 and Maf proteins in myeloma genesis, targeting the USP7/Maf axle is a potential strategy to the precision therapy of MM.

ID1 Is Critical for Tumorigenesis and Regulates Chemoresistance in Glioblastoma

Glioblastoma is the most common primary brain tumor in adults. While the introduction of temozolomide chemotherapy has increased long-term survivorship, treatment failure and rapid tumor recurrence remains universal. The transcriptional regulatory protein, inhibitor of DNA-binding-1 (ID1), is a key regulator of cell phenotype in cancer. We show that CRISPR-mediated knockout of ID1 in glioblastoma cells, breast adenocarcinoma cells, and melanoma cells dramatically reduced tumor progression in all three cancer systems through transcriptional downregulation of EGF, which resulted in decreased EGFR phosphorylation. Moreover, ID1-positive cells were enriched by chemotherapy and drove tumor recurrence in glioblastoma. Addition of the neuroleptic drug pimozide to inhibit ID1 expression enhanced the cytotoxic effects of temozolomide therapy on glioma cells and significantly prolonged time to tumor recurrence. Conclusively, these data suggest ID1 could be a promising therapeutic target in patients with glioblastoma. SIGNIFICANCE: These findings show that the transcriptional regulator ID1 is critical for glioblastoma initiation and chemoresistance and that inhibition of ID1 enhances the effect of temozolomide, delays tumor recurrence, and prolongs survival.

Different susceptibility to fatty liver-haemorrhagic syndrome in young and older layers and the interaction on blood LDL-C levels between oestradiols and high energy-low protein diets

1. The objective of the study was to investigate the susceptibility of young and older laying hens to fatty liver-haemorrhagic syndrome (FLHS) and to evaluate the reliability of different blood lipid fractions for predicting or diagnosing FLHS. 2. Forty young hens and 40 older hens were caged individually. Each group of hens was randomly allotted to four treatments for 21 days: either a control, an oestradiol group, a high energy-low protein diet (HELPD) group or a HELPD + oestradiol group. Blood levels of oestradiol, triglyceride (TG), cholesterol (CHOL), high density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), liver total lipids, hepatic haemorrhagic scores and productive performance were assessed. 3. In older hens, β-oestradiol increased (P < 0.05) liver total lipids, hepatic haemorrhagic scores and the incidence of FLHS but reduced (P < 0.05) productive performance; however, such changes were not observed in young hens. 4. In two groups of hens, serum TG, CHOL and HDL-C levels were increased (P < 0.001) by β-oestradiol. Hens with FLHS had higher serum TG, CHOL and HDL-C (P < 0.001) than non-FLHS birds in the older layer group of hens. 5. An interaction (β-oestradiol × HELPD) (P < 0.05) for LDL-C levels was observed in both groups of hens. In young hens, β-oestradiol induced a decrease (P = 0.004) in serum LDL-C levels but the effect was attenuated by HELPD. In older hens, HELPD caused an increase (P = 0.02) in serum LDL-C although the effect depended on the presence of β-oestradiol. 6. In conclusion, older layers were more susceptible to FLHS than young layers after oestradiol treatment. Blood TG, CHOL and HDL-C rather than LDL-C levels can be used as a prediction tool for the overall susceptibility to FLHS in older rather than young layers. There were interactions between oestradiol and HELPD on blood LDL-C levels in laying hens.

Recombinant human granulocyte- colony stimulating factor in women with unexplained recurrent pregnancy losses: a randomized clinical trial

STUDY QUESTION

Does administration of recombinant human granulocyte colony stimulating factor (rhG-CSF) in the first trimester improve pregnancy outcomes, among women with a history of unexplained recurrent pregnancy loss?

SUMMARY ANSWER

rhG-CSF administered in the first trimester of pregnancy did not improve outcomes among women with a history of unexplained recurrent pregnancy loss.

WHAT IS KNOWN ALREADY

The only previous randomized controlled study of granulocyte colony stimulating factor in recurrent miscarriage in 68 women with unexplained primary recurrent miscarriage found a statistically significant reduction in miscarriage and improvement in live birth rates. A further four observational studies where G-CSF was used in a recurrent miscarriage population were identified in the literature, two of which confirmed statistically significant increase in clinical pregnancy and live birth rates.

STUDY DESIGN, SIZE, DURATION

A randomized, double-blind, placebo controlled clinical trial involving 150 women with a history of unexplained recurrent pregnancy loss was conducted at 21 sites with established recurrent miscarriage clinics in the United Kingdom between 23 June 2014 and 05 June 2016. The study was coordinated by University of Birmingham, UK.

PARTICIPANTS/MATERIALS, SETTING, METHODS

One hundred and fifty women with a history of unexplained recurrent pregnancy loss: 76 were randomized to rhG-CSF and 74 to placebo. Daily subcutaneous injections of recombinant human granulocyte - colony stimulating factor 130 μg or identical appearing placebo from as early as three to five weeks of gestation for a maximum of 9 weeks. The trial used central randomization with allocation concealment. The primary outcome was clinical pregnancy at 20 weeks of gestation, as demonstrated by an ultrasound scan. Secondary outcomes included miscarriages, livebirth, adverse events, stillbirth, neonatal birth weight, changes in clinical laboratory variables following study drug exposure, major congenital anomalies, preterm births and incidence of anti-drug antibody formation. Analysis was by intention to treat.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 340 participants were screened for eligibility of which 150 women were randomized. 76 women (median age, 32[IQR, 29-34] years; mean BMI, 26.3[SD, 4.2]) and 74 women (median age, 31[IQR, 26-33] years; mean BMI, 25.8[SD, 4.2]) were randomized to placebo. All women were followed-up to primary outcome, and beyond to live birth. The clinical pregnancy rate at 20 weeks, as well as the live birth rate, was 59.2% (45/76) in the rhG-CSF group, and 64.9% (48/74) in the placebo group, giving a relative risk of 0.9 (95% CI: 0.7-1.2; P = 0.48). There was no evidence of a significant difference between the groups for any of the secondary outcomes. Adverse events (AEs) occurred in 52 (68.4%) participants in rhG-CSF group and 43 (58.1%) participants in the placebo group. Neonatal congenital anomalies were observed in 1/46 (2.1%) of babies in the rhG-CSF group versus 1/49 (2.0%) in the placebo group (RR of 0.9; 95% CI: 0.1-13.4; P = 0.93).

LIMITATIONS, REASONS FOR CAUTION

This trial was conducted in women diagnosed with unexplained recurrent pregnancy loss and therefore no screening tests (commercially available) were performed for immune dysfunction related pregnancy failure/s.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first multicentre study and largest randomized clinical trial to investigate the efficacy and safety of granulocyte human colony stimulating factor in women with recurrent miscarriages. Unlike the only available single center RCT, our trial showed no significant increase in clinical pregnancy or live births with the use of rhG-CSF in the first trimester of pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

This study was sponsored and supported by Nora Therapeutics, Inc., 530 Lytton Avenue, 2nd Floor, Palo Alto, CA 94301, USA. Darryl Carter was the co-founder and VP of research, Nora Therapeutics, Inc. and held shares in the company. He holds a patent for the use of recombinant human granulocyte colony stimulating factor to reduce unexplained recurrent pregnancy loss. Mark Joing, Paul Kwon and Jeff Tong were or are employees of Nora Therapeutics, Inc. No other potential conflict of interest relevant to this article was reported.

TRIAL REGISTRATION NUMBER

EUDRACT No: 2014-000084-40; ClinicalTrials.gov Identifier: NCT02156063.

TRIAL REGISTRATION DATE

31 Mar 2014.

DATE OF FIRST PATIENT’S ENROLMENT

23 Jun 2014.

[Efficacy analysis of unrelated cord blood transplantation in the treatment of refractory and relapsed adult acute leukemia]

目的

探讨非血缘脐血移植（UCBT）挽救治疗难治复发急性白血病（AL）患者的临床疗效和安全性。

方法

回顾性分析2009年11月至2017年5月22例行UCBT挽救治疗的难治复发成人AL患者的临床资料，全部患者采用清髓性预处理方案，均采用环孢素A/短程霉酚酸酯方案预防GVHD。

结果

①22例患者中男9例，女13例，中位年龄23（15~44）岁；中位体重52.5（43~82）kg。所有患者回输脐血有核细胞中位数为3.07（1.71~5.30）×10⁷/kg（受者体重），CD34⁺细胞中位数为1.60（0.63~3.04）×10⁵/kg（受者体重）。②移植后42 d髓系累积植入率为95.5%（95%CI 45.2%~99.7%），中位植入时间为19（13~27）d；移植后120 d血小板累积植入率为81.8%（95%CI 54.2%~93.6%），中位植入时间为42（20~164）d。③Ⅱ~Ⅳ度、Ⅲ~Ⅳ度急性GVHD发生率以及慢性GVHD 2年累积发生率分别为36.4%、13.6%和40.3%。④移植后180 d移植相关死亡率为22.7%；2年累积复发率为18.7%（95%CI 3.6%~42.5%），2年累积无病生存率及累积总生存率分别为53.7%和58.1%。

结论

对于常规化疗无效的难治复发成人AL患者，初步结果显示采用UCBT安全、有效。

[Comparison of unrelated cord blood transplantation and HLA-identical sibling peripheral blood stem cell transplantation for the treatment of adult hematological malignancies]

Objective: To compare the efficacy of unrelated cord blood transplantation (UCBT) and HLA-identical sibling peripheral blood stem cell transplantation (PBSCT) for the treatment of adult hematological malignancies. Methods: From April 2011 to December 2015, a total of 81 patients receiving single-unit UCBT and 57 patients receiving HLA-identical sibling PBSCT were enrolled in this study. All of the patients received myelablative conditioning. Cyclosporine combined with mycophenolate mofetil was adopted for GVHD prophylaxis. Results: The cumulative incidence of neutropil engraftment at day-42 was 95.0% and 100% in UCBT and sibling PBSCT groups, respectively (P=0.863) . Platelet engraftment at day 100 was 87.3% (95%CI 76.8%-93.1%) in UCBT group, which was significantly lower than that of sibling PBSCT group[98.2% (95%CI 87.3%-99.7%) ] (P=0.005) . There were no significant differences in terms of Ⅱ-Ⅳ acute GVHD or Ⅲ-Ⅳ acute GVHD in two groups (P=0.142, 0.521) . The 3-year chronic GVHD and extensive chronic GVHD were 14.9% (95%CI 5.2%-23.5%) and 11.2% (95%CI 2.9%-18.7%) , respectively in UCBT group, which was significantly lower than that of sibling PBSCT group[35.2% (95%CI 19.4%-47.8%) , 31.4% (95%CI 16.2%-43.9%) ] (P=0.008, 0.009) . The 3-year transplant-related mortality (TRM) was similar between two groups (30.1% vs 23.2%, P=0.464) . The relapse rate at 3-year in UCBT group[12.9% (95%CI 6.6%-21.5%) ]was significantly lower than that in sibling PBSCT group[24.3% (95%CI 13.5%-36.8%) ] (P=0.039) . There were no significant differences in terms of overall survival (OS) and disease-free survival (DFS) between two groups (58.6% vs 54.8%, P=0.634; 57.0% vs 52.4%, P=0.563) . But GVHD-free and relapse-free survival (GRFS) in UCBT group [55.7% (95%CI 44.1%-65.8%) ]was significantly higher than that of sibling PBSCT group[42.9% (95%CI 29.8%-55.3%) ] (P=0.047) . Conclusions: For adult hematological malignancies, the incidences of acute GVHD and TRM were similar between UCBT and sibling PBSCT recipients, and the incidences of chronic GVHD and relapse were lower in UCBT recipients. UCBT recipients had higher GRFS rate although OS and DFS were similar between two groups, which may reflect the real recovery and better quality of life following UCBT.

Structural and Functional Characterization of Ubiquitin Variant Inhibitors of USP15

The multi-domain deubiquitinase USP15 regulates diverse eukaryotic processes and has been implicated in numerous diseases. We developed ubiquitin variants (UbVs) that targeted either the catalytic domain or each of three adaptor domains in USP15, including the N-terminal DUSP domain. We also designed a linear dimer (diUbV), which targeted the DUSP and catalytic domains, and exhibited enhanced specificity and more potent inhibition of catalytic activity than either UbV alone. In cells, the UbVs inhibited the deubiquitination of two USP15 substrates, SMURF2 and TRIM25, and the diUbV inhibited the effects of USP15 on the transforming growth factor β pathway. Structural analyses revealed that three distinct UbVs bound to the catalytic domain and locked the active site in a closed, inactive conformation, and one UbV formed an unusual strand-swapped dimer and bound two DUSP domains simultaneously. These inhibitors will enable the study of USP15 function in oncology, neurology, immunology, and inflammation.

Engineered SH2 domains with tailored specificities and enhanced affinities for phosphoproteome analysis

Protein phosphorylation is the most abundant post-translational modification in cells. Src homology 2 (SH2) domains specifically recognize phosphorylated tyrosine (pTyr) residues to mediate signaling cascades. A conserved pocket in the SH2 domain binds the pTyr side chain and the EF and BG loops determine binding specificity. By using large phage-displayed libraries, we engineered the EF and BG loops of the Fyn SH2 domain to alter specificity. Engineered SH2 variants exhibited distinct specificity profiles and were able to bind pTyr sites on the epidermal growth factor receptor, which were not recognized by the wild-type Fyn SH2 domain. Furthermore, mass spectrometry showed that SH2 variants with additional mutations in the pTyr-binding pocket that enhanced affinity were highly effective for enrichment of diverse pTyr peptides within the human proteome. These results showed that engineering of the EF and BG loops could be used to tailor SH2 domain specificity, and SH2 variants with diverse specificities and high affinities for pTyr residues enabled more comprehensive analysis of the human phosphoproteome. STATEMENT: Src Homology 2 (SH2) domains are modular domains that recognize phosphorylated tyrosine embedded in proteins, transducing these post-translational modifications into cellular responses. Here we used phage display to engineer hundreds of SH2 domain variants with altered binding specificities and enhanced affinities, which enabled efficient and differential enrichment of the human phosphoproteome for analysis by mass spectrometry. These engineered SH2 domain variants will be useful tools for elucidating the molecular determinants governing SH2 domains binding specificity and for enhancing analysis and understanding of the human phosphoproteome.

A feed forward loop enforces YAP/TAZ signaling during tumorigenesis

In most solid tumors, the Hippo pathway is inactivated through poorly understood mechanisms that result in the activation of the transcriptional regulators, YAP and TAZ. Here, we identify NUAK2 as a YAP/TAZ activator that directly inhibits LATS-mediated phosphorylation of YAP/TAZ and show that NUAK2 induction by YAP/TAZ and AP-1 is required for robust YAP/TAZ signaling. Pharmacological inhibition or loss of NUAK2 reduces the growth of cultured cancer cells and mammary tumors in mice. Moreover, in human patient samples, we show that NUAK2 expression is elevated in aggressive, high-grade bladder cancer and strongly correlates with a YAP/TAZ gene signature. These findings identify a positive feed forward loop in the Hippo pathway that establishes a key role for NUAK2 in enforcing the tumor-promoting activities of YAP/TAZ. Our results thus introduce a new opportunity for cancer therapeutics by delineating NUAK2 as a potential target for re-engaging the Hippo pathway.

The Hippo pathway is frequently dysregulated in cancer. Here, the authors identify NUAK2 as negative regulator of the Hippo pathway from a siRNA kinome screen and show that NUAK2 promotes YAP/TAZ nuclear localisation while NUAK2 is a transcriptional target of YAP/TAZ, thus providing a feed forward loop to promote tumorigenesis.

Ureteral tunnel length versus ureteral orifice configuration in the determination of ureterovesical junction competence: A computer simulation model

INTRODUCTION

The long-held belief that a ureteral re-implant tunnel should be five times the diameter of the ureter, as proposed by Paquin in 1959, ignores the effect of the orifice on the occurrence of reflux. In 1969, Lyon proposed that the shape of the ureteral orifice (UO) is more important than the intravesical tunnel. However, both theories missed quantitative evidence from principles of physics. The goal of the current study was to test Lyon's theory through numerical models (i.e. to quantify the sensitivity of ureterovesical junction (UVJ) competence to intravesical tunnel length and to the UO).

MATERIALS AND METHODS

The closure of a three-dimensional spatial configuration of ureter, constrained within a bladder, was simulated. Two common UO shapes (i.e. golf type vs 2-mm volcano type (Summary Fig.)), and two different intravesical ureteral tunnel length/diameter ratios (3:1 and 5:1) were examined. The required closure pressures were then compared.

RESULTS

The UO was a significant factor in determining closure pressure. Given the same intravesical ureteral tunnel length/diameter ratio, the required closure pressure for the volcanic orifice was 78% less than that for the golf orifice. On the other hand, the intravesical ureteral tunnel length/diameter ratio had minimal effect on the required closure pressure. As the intravesical ureteral tunnel length/diameter ratio changed from 3:1 to 5:1, the required closure pressure was reduced by less than 7%, regardless of the orifice shape.

CONCLUSIONS

The simulation results showed that UVJ competence was more sensitive to a 2-mm protrusion of the UO compared to an increase in the intravesical tunnel length from 3:1 to 5:1. This agrees with Lyon's theory, and at the same time challenges Paquin's 5:1 rule. Researchers could use this information to consider the UO configuration in further animal, human, computer or material models.