Macrocephaly and developmental delay caused by missense variants in RAB5C.

Rab GTPases are important regulators of intracellular vesicular trafficking. RAB5C is a member of the Rab GTPase family that plays an important role in the endocytic pathway, membrane protein recycling and signaling. Here we report on 12 individuals with nine different heterozygous de novo variants in RAB5C. All but one patient with missense variants (n = 9) exhibited macrocephaly, combined with mild-to-moderate developmental delay. Patients with loss of function variants (n = 2) had an apparently more severe clinical phenotype with refractory epilepsy and intellectual disability but a normal head circumference. Four missense variants were investigated experimentally. In vitro biochemical studies revealed that all four variants were damaging, resulting in increased nucleotide exchange rate, attenuated responsivity to guanine exchange factors and heterogeneous effects on interactions with effector proteins. Studies in C. elegans confirmed that all four variants were damaging in vivo and showed defects in endocytic pathway function. The variant heterozygotes displayed phenotypes that were not observed in null heterozygotes, with two shown to be through a dominant negative mechanism. Expression of the human RAB5C variants in zebrafish embryos resulted in defective development, further underscoring the damaging effects of the RAB5C variants. Our combined bioinformatic, in vitro and in vivo experimental studies and clinical data support the association of RAB5C missense variants with a neurodevelopmental disorder characterized by macrocephaly and mild-to-moderate developmental delay through disruption of the endocytic pathway.

Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070.

A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona's bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.

Fast inflows as the adjacent fuel of supermassive black hole accretion disks in quasars.

Quasars, which are exceptionally bright objects at the centres (or nuclei) of galaxies, are thought to be produced through the accretion of gas into disks surrounding supermassive black holes1-3. There is observational evidence at galactic and circumnuclear scales4 that gas flows inwards towards accretion disks around black holes, and such an inflow has been measured at the scale of the dusty torus that surrounds the central accretion disk5. At even smaller scales, inflows close to an accretion disk have been suggested to explain the results of recent modelling of the response of gaseous broad emission lines to continuum variations6,7. However, unambiguous observations of inflows that actually reach accretion disks have been elusive. Here we report the detection of redshifted broad absorption lines of hydrogen and helium atoms in a sample of quasars. The lines show broad ranges of Doppler velocities that extend continuously from zero to redshifts as high as about 5,000 kilometres per second. We interpret this as the inward motion of gases at velocities comparable to freefall speeds close to the black hole, constraining the fastest infalling gas to within 10,000 gravitational radii of the black hole (the gravitational radius being the gravitational constant multiplied by the object mass, divided by the speed of light squared). Extensive photoionization modelling yields a characteristic radial distance of the inflow of approximately 1,000 gravitational radii, possibly overlapping with the outer accretion disk.

Influence of Temperature on Susceptibility of CVS. Tifguard and Georgia-06G Peanut to Meloidogyne arenaria.

Tifguard was released in 2008 as a peanut cultivar with a high level of resistance to Meloidogyne arenaria. Our objective was to determine the role of temperature on infection and development of M. arenaria in Tifguard compared to that in the nematode susceptible cultivar, Georgia-06G. Temperature affected the rate of nematode infection and development in both Tifguard and Georgia-06G (P ≤ 0.05). In Georgia-06G, egg-laying females were observed 25, 20 or 25 days after inoculation at 28°C, 31°C, and 34°C, respectively. There were greater numbers of nematodes entering roots and acceleration of development in response to 31°C compared with that at 28°C. There was, however, a decrease in the number of nematodes entering roots and their development was retarded at 34°C compared with that occurring at 31°C. Although second-stage juveniles penetrated Tifguard roots, they did not develop further at 28°C or 31°C; however, at 34°C both females, males, and a few egg-laying females of M. arenaria were observed. The optimum temperature for nematode infection and development was 31°C in Georgia-06G. In summary, it is unlikely that high soil temperatures would lessen the effectiveness of the nematode resistance gene in Tifguard.

Dynamic contrast-enhanced MR imaging of carotid vasa vasorum in relation to coronary and cerebrovascular events.

BACKGROUND AND AIMS: Dynamic contrast-enhanced MR imaging (DCE-MRI) provides a noninvasive approach to the functional status of carotid adventitial vasa vasorum. Contrast extravasation rate, or Ktrans, derived from kinetic modeling of adventitial enhancement, has been correlated with plaque neovascularization and inflammation. This study sought to clarify the clinical implications of Ktrans by evaluating its relationship with documented cardiovascular events (CVE). METHODS: Seventy patients with carotid plaque at clinical ultrasound examination were recruited and imaged with a previously-described bright-blood DCE-MRI protocol (spatial resolution: 0.55 × 0.58 mm2; time resolution: 18 s). Patients were classified by the presence of documented coronary and/or cerebrovascular events. Adventitial Ktrans was estimated via kinetic modeling of outer wall enhancement as captured by DCE-MRI. RESULTS: After excluding six patients with insufficient image quality, 64 patients (66 ± 12 years, 51 male) had DCE-MRI measurements. Patients with documented CVE showed significantly higher adventitial Ktrans than those without (0.056 ± 0.024 versus 0.034 ± 0.008 min-1, p < 0.001), whereas comparable measurements were seen among the subgroups with CVE (p > 0.05): 0.054 ± 0.027 min-1 in patients with coronary events alone, 0.056 ± 0.018 min-1 in patients with cerebrovascular events alone, and 0.069 ± 0.022 min-1 in patients with both. Carotid adventitial Ktrans was negatively correlated with time since clinical event (Spearman's rho = -0.40, p = 0.003). CONCLUSIONS: Patients with documented CVE demonstrated increased rate of contrast extravasation from carotid adventitial vasa vasorum on DCE-MRI irrespective of the territory of events. Systemic factors implicated in the pathophysiology of acute atherothrombotic events may influence the functional status of adventitial vasa vasorum.

A novel model for evaluating thrombolytic therapy in dogs with ST-elevation myocardial infarction.

BACKGROUND: There is still no standard large animal model for evaluating the effectiveness of potential thrombolytic therapies. Here, we aimed to develop a new beagle model with ST-elevation myocardial infarction (STEMI) by injecting autologous emboli with similar components of coronary thrombus. METHODS: 18 male beagles were included and divided into three groups: red embolus group (n = 6), white embolus group (n = 6) or white embolus + rt-PA group (n = 6). Autologous emboli were infused into the mid-distal region of the left anterior descending coronary artery. The composition of embolus was examined by scanning electron microscope (SEM). Coronary angiography was performed to verify the status of embolism. Myocardial infarct size was measured by 2, 3, 5- triphenyltetrazolium chloride (TTC) staining. RESULTS: Red thrombus was characteristic of loose reticular structure of erythrocytes under SEM, while the white embolus had compacted structure that mainly consisted of a dense mass of fibrin. Coronary angiography showed the recanalization rate was 2/6 in the red embolus group versus 0/6 in the white embolus group in three hours after occlusion. Arrhythmia, resolution of ST-segment elevation and lower T wave on the electrocardiogram appeared in the red embolus group but not in the white embolus group. Another six dogs with white thrombi were treated with rt-PA. Five out of six dogs exhibited coronary recanalization after two hours of therapy, compared to zero dogs without rt-PA treatment. The size of myocardial infarction in rt-PA group reduced significantly compared with white embolus group using TTC staining method. CONCLUSIONS: The white embolism model was more convenient experimentally and had a higher uniformity, stability and success rate. The major innovation of our study is that we applied fibrin-rich white thrombi to establish beagle model possessing features of clinically observed coronary thrombi in time window of intravenous thrombolysis of STEMI. This model can be used to evaluate new thrombolytic drugs for the treatment of STEMI.

A pig model of ischemic mitral regurgitation induced by mitral chordae tendinae rupture and implantation of an ameroid constrictor.

A miniature pig model of ischemic mitral regurgitation (IMR) was developed by posterior mitral chordae tendinae rupture and implantation of an ameroid constrictor. A 2.5-mm ameroid constrictor was placed around the left circumflex coronary artery (LCX) of male Tibetan miniature pigs to induce ischemia, while the posterior mitral chordae tendinae was also ruptured. X-ray coronary angiography, ECG analysis, echocardiography, and magnetic resonance imaging (MRI) were used to evaluate heart structure and function in pigs at baseline and one, two, four and eight weeks after the operation. Blood velocity of the mitral regurgitation was found to be between medium and high levels. Angiographic analyses revealed that the LCX closure was 10-20% at one week, 30-40% at two weeks and 90-100% at four weeks subsequent ameroid constrictor implantation. ECG analysis highlighted an increase in the diameter of the left atria (LA) at two weeks post-operation as well as ischemic changes in the left ventricle (LV) and LA wall at four weeks post-operation. Echocardiography and MRI further detected a gradual increase in LA and LV volumes from two weeks post-operation. LV end diastolic and systolic volumes as well as LA end diastolic and systolic volume were also significantly higher in pig hearts post-operation when compared to baseline. Pathological changes were observed in the heart, which included scar tissue in the ischemic central area of the LV. Transmission electron microscopy highlighted the presence of contraction bands and edema surrounding the ischemia area, including inflammatory cell infiltration within the ischemic area. We have developed a pig model of IMR using the posterior mitral chordae tendineae rupture technique and implantation of an ameroid constrictor. The pathological features of this pig IMR model were found to mimic the natural history and progression of IMR in patients.

Specific and functional diversity of endophytic bacteria from pine wood nematode Bursaphelenchus xylophilus with different virulence.

Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is one of the most devastating diseases of Pinus spp. The PWN was therefore listed as one of the most dangerous forest pests in China meriting quarantine. Virulence of the PWN is closely linked with the spread of PWD. However, main factors responsible for the virulence of PWNs are still unclear. Recently epiphytic bacteria carried by PWNs have drawn much attention. But little is known about the relationship between endophytic bacteria and virulence of B. xylophilus. In this research, virulence of ten strains of B. xylophilus from different geographical areas in six provinces of China and four pine species were tested with 2-year-old seedlings of Pinus thunbergii. Endophytic bacteria were isolated from PWNs with different virulence to investigate the relationship between the bacteria and PWN virulence. Meanwhile, the carbon metabolism of endophytic bacteria from highly and low virulent B. xylophilus was analyzed using Biolog plates (ECO). The results indicated that ten strains of PWNs showed a wide range of virulence. Simultaneously, endophytic bacteria were isolated from 90% of the B. xylophilus strains. The dominant endophytic bacteria in the nematodes were identified as species of Stenotrophomonas, Achromobacter, Ewingella, Leifsonia, Rhizobium, and Pseudomonas using molecular and biochemical methods. Moreover, S. maltophilia, and A. xylosoxidans subsp. xylosoxidans were the predominant strains. Most of the strains (80%) from P. massoniana contained either S. maltophilia, A. xylosoxidans, or both species. There was a difference between the abilities of the endophytic bacteria to utilize carbon sources. Endophytic bacteria from highly virulent B. xylophilus had a relatively high utilization rate of carbohydrate and carboxylic acids, while bacteria from low virulent B. xylophilus made better use of amino acids. In conclusion, endophytic bacteria widely exist in B. xylophilus from different pines and areas; and B. xylophilus strains with different virulence possessed various endophytic bacteria and diverse carbon metabolism which suggested that the endophytic bacteria species and carbon metabolism might be related with the B. xylophilus virulence.

[Evaluation of very early neointimal coverage post drug-eluting stent implantation using optical coherence tomography].

OBJECTIVE: To investigate the neointimal coverage at the very early phase after drug-eluting stent (DES) implantation using optical coherence tomography (OCT). METHODS: OCT examination was performed immediately after stent deployment and about one week post stenting in 12 patients with coronary artery disease to detect neointimal coverage and stent thrombus. Sirolimus eluting stent implantation was also performed in 5 healthy Chinese minipigs, OCT and histopathology examination were made one week later in these minipigs. RESULTS: (1) Twenty-nine DES were implanted in 12 patients. There was no major cardiovascular event post stenting. The mean time of follow-up was (7.7 ± 2.6) d, the mean percentage of stent coverage was (21.8 ± 17.7)%, and neointimal hyperplasia thickness was (42.9 ± 32.2) µm and the percentage of malapposition struts was (1.5 ± 3.0)%, respectively. Mural stent thrombus was found in 2 of the 12 patients (the percentage is 16.7%). (2) In the minipigs model, OCT evidenced that (43.2 ± 11.5)% struts were covered by neointima with a mean neointimal hyperplasia thickness of (24.0 ± 8.5) µm at one week. Histopathology examination illustrated that the neointima was mainly consisted of proteoglycan, inflammation cells, fibrin and organized thrombus at the very early phase after DES implantation, while endothelial cells were barely found on the neointima. CONCLUSIONS: Neointimal coverage is found as early as one week after DES implantation by OCT. The covered struts rate is very low and the main components of neointima are proteoglycan, inflammation cells, fibrin and organized thrombus. Re-endothelialization is rather poor at the very early phase post DES implantation.

[Establishment and evaluation of acute pulmonary thromboembolism model in minipig].

OBJECTIVE: To establish and evaluate an acute pulmonary embolism (APTE) model by selective thromboembolism of lower left pulmonary artery in minipig. METHODS: Through intervention technique, a guiding catheter was inserted via femoral vein into pulmonary artery. And quantitative autologous venous thrombus was injected into the selected lower left pulmonary arteries in 8 minipigs. Thus the intended APTE model was established by selective thromboembolism of lower left pulmonary artery. Hemodynamic parameters were monitored. And computed tomography (CT) and macroscopic dissection were performed to evaluate the minipig APTE model. RESULTS: The measurements of mean pulmonary artery pressure (MPAP, mm Hg, 1 mm Hg = 0.133 kPa) and pulmonary capillary wedge pressure (PCWP, mm Hg) immediately increased significantly after thromboembolism versus the baseline values (MPAP: 42.0 ± 3.4 vs 20.2 ± 3.0, PCWP: 8 ± 2 vs 4 ± 3, both P < 0.05) and stayed at a higher level during the following 2 h. No significant difference existed between the value of cardiac output (CO) at 2 h post-thromboembolism and its baseline counterpart. Moreover, systemic arterial pressure (SAP, mm Hg) and heart rate (HR, beats/min) significantly increased after embolism versus the baseline values (SAP: 102 ± 12 vs 80 ± 7, HR: 119 ± 22 vs 86 ± 14, P = 0.008). Pulmonary arteriography, CT scan and gross anatomy all demonstrated that the selected lower left pulmonary arteries was successfully embolized. CONCLUSION: The establishment of APTE model by selective thromboembolism of lower left pulmonary artery is feasible, well-controlled and stable in minipigs.

[Observation by transmission electron microscope and identification of endophytic bacteria isolated from Bursaphelenchus xylophilus and B. mucronatus].

OBJECTIVE: The pine wood nematode, Bursaphlenchus xylophilus, morphologically similar to B. mucronatus, is the pathogen of pine wilt disease. This study was focused on the endophytic bacteria present in these nematodes. METHODS: Detailed observations were made on sections of all parts of the two types of nematodes by transmission electron microscope. The nematodes were surface-sterilized by soaking in 1% mercuric chloride and antibiotic mixture, and then ground and cultured on nutrient agar plate. The physiological and biochemical characteristics combined with molecular characterization of bacteria were analyzed and identified. RESULTS: Endophytic bacteria were found in intestines of the two nematodes by transmission electron microscope observations. On the basis of surface sterilization, total three bacteria strains were obtained from B. xylophilus and B. mucronatus. These bacteria belong to Stenotrophomonas and Ewingella. CONCLUSION: It confirms the presence of endophytic bacteria in Bursaphelenchus xylophilus and B. mucronatus and these bacteria may play a physical and ecological roles in nematodes.

[Relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model].

OBJECTIVE: To study the relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model. METHODS: Twenty normal minipigs were randomly divided into group A (implanted with 316L bare metal stents), group B (implanted with 605L bare metal stents), group C (implanted with PLGA coating 605L stents), and group D (implanted with rapamycin-loaded PLGA coating 605L stents). Each minipig was implanted with two same stents in left anterior descending artery and right coronary artery. Four weeks later, the animals were sacrificed and histomorphometric measurements on the stent-segment coronary arteries were made to calculate the correlation between inflammation area and neointimal area. RESULTS: Group D had the smallest neointimal area [(0.64 +/- 0.38) mm2, P < 0. 001] and inflammation area (median 0.00 mm2, P = 0.009) among all the groups, while there were no statistical differences among group A, B, and C in neointimal area [(2.09 +/- 0.90), (2.11 +/- 1.07), and (1.42 +/- 0.35) mm2 respectively] and in inflammation area (0.22 , 0.21, and 0.09 mm2, respectively). Bivariate correlation analysis showed that the inflammation area was positively correlated with the neointimal area (P < 0.001, correlation coefficient = 0.719). When stent type, mean injury score, and EEL area were adjusted, partial correlations analysis showed that the inflammation area was still positively correlated with the neointimal area (P = 0.01, correlation coefficient = 0.498). CONCLUSION: Inflammation promotes the neointimal proliferation after coronary stent implantation. Sirolimus-eluting stent may reduce the inflammatory response.

[Hemodynamic performance of newly developed composite stentless porcine aortic valve: in vitro testing and in vivo experiment with sheep].

OBJECTIVE: To investigate the effects of a newly developed composite stentless porcine aortic valve constructed from noncoronary leaflets of three porcine aortic valves. METHODS: Fresh porcine hearts with ascending aorta were obtained from a slaughterhouse. The porcine aortic roots with ascending aorta and anterior leaflet of mitral valve and partial ventricular septum were dissected out and were pressurized to maintain their natural anatomical shapes with the leaflets floating freely at zero-pressure. Three noncoronary leaflets fixed in 0.6% glutaraldehyde were carefully matched for size and symmetry to construct a novel composite stentless porcine aortic valve. The lower margin and outside of the valve was covered with a piece of bovine pericardium. The novel stentless valves were tested in vitro pulsatile flow to detect the effective orifice area (EOA) and mean pressure difference (DeltaP) of the valve compared with the stented bovine pericardial bioprostheses of the same size. Sixteen male juvenile sheep underwent implantation of the novel valves in the supra-annular position in under cardio-pulmonary bypass. The intraoperative and postoperative echocardiography and pathological specimen were given to evaluate the hemodynamic performance and observed in the respects of a long-term survival, function of valve and pathological specimen. RESULTS: Since novel valves had the unfavorable muscle-based right coronary leaflet characteristic of porcine valve removed it had larger EOA. Pulsatile flow testing indicated that the EOA of the 3 novel valves was (3.47 +/- 0.15), (3.69 +/- 0.11), and (3.92 +/- 0.18) cm2 respectively, all significantly greater than those of the stented bovine pericardial bioprosthesis [(2.00 +/- 0.16), (2.21 +/- 0.26), and (2.37 +/- 0.42) cm2 respectively] at each integral simulated cardiac output between 3 - 6 L/min (all P < 0.05), while the DeltaP levels of the novel valves were (2.35 +/- 0.41), (3.10 +/- 0.20), and (3.56 +/- 0.16) mm Hg respectively, all significantly lower than those of the stented bovine pericardial bioprosthesis [(4.98 +/- 0.46), (6.82 +/- 1.27), and (8.40 +/- 1.83) mm Hg respectively, all P < 0.05]. Twelve of the sixteen sheep survived after operation. Five of them had lived for more than 90 days, 3 more than 180 days, and 2 more than 360 days. The intra-operative echocardiographic analyses showed low DeltaP [(3.90 +/- 0.78) mm Hg] and no regurgitation in all sheep. After 15 to 360 days, all valves performed excellently. The sheep were postoperatively sacrificed in 5 d, 15 d, 45 d, 90 d, 180 d, or 300 d respectively. Necropsy revealed the valves had a low to mild level of calcification, without periprosthetic leakage and overgrowth of fibrous tissue. CONCLUSION: The newly developed composite stentless porcine aortic valves show excellent hemodynamic performance with lower transvalvular pressure gradient and are relatively easy to implant.

[Chronic sheep modal for pulmonary valve implantation with domestic bileaflet mechanical prosthesis].

OBJECTIVE: The aim of this study was to identify the long-term character of the domestic bileaflet mechanical valve in the chronic implanted sheep model and to evaluate the potential value of the modal. METHODS: Six adult sheep underwent implanted mechanical bileaflet valve in pulmonary position under the cardio-pulmonary bypass with beating heart. The chronic implanted sheep model was built up and observed in the respects of a long-term survival, function of prosthesis and pathological specimen. RESULTS: Six adult sheep survived with good condition after operation. The average survival period of six sheep was (221 +/- 208) days. Two sheep were postoperatively sacrificed in 41 and 71 days, respectively. The necropsy revealed normal valve function without thrombosis, periprosthetic leakage and overgrowth of fibrous tissue. One sheep died from dysfunction of prosthetic valve at the postoperative 196 days. The reason was the prosthetic thrombosis with slight overgrowth of fibrous tissue in periprosthesis. The other two sheep died from severe anemia at the postoperative 196 days and 234 days, and the autopsy revealed no abnormal finding else. And one remained to survive with good condition up to now (over 617 days) and was checked by Doppler echocardiogram twice at the postoperative 438 days and 479 days, respectively. The results showed normal function of the bileaflet valve in pulmonary position. CONCLUSION: The long-term good effects would be achieved by using the implanted new domestic bileaflet valve in pulmonary position of sheep.