Characteristics of children with IgA nephropathy.

BACKGROUND: We analyzed the demographic and clinical characteristics of children with immunoglobulin A (IgA) nephropathy using data in the first pages of electronic health records of 22 hospitals from 2016 to 2018. METHODS: Information collected included gender, age, infection site, etiological infection, acute kidney injury (AKI), and chronic kidney disease (CKD) stages 2-5. We analyzed the gender and age distribution of children with IgA nephropathy, the characteristics of children complicated with AKI and CKD, and the influence of geographical distribution and economic status on the incidence of IgA nephropathy. RESULTS: We included a total of 4006 patients with IgA nephropathy. Incidence in males gradually increased with age. Seventy-nine cases (1.97%) had AKI. We found no significant difference in gender (P = 0.19) or age (P = 0.07) between the AKI and non-AKI groups. Twenty-nine patients had CKD (0.72%), who were significantly older than those in the non-CKD group (P < 0.0001). The incidence of IgA nephropathy in less-developed areas was significantly lower than that in developed areas (P = 0.0002). CONCLUSIONS: The incidence of IgA nephropathy was high mainly in males. Age was an important factor affecting CKD. The disease was related to environment and economic status. IMPACT: We analyze the demographic and clinical characteristics of children with immunoglobulin A (IgA) nephropathy using data in the first pages of electronic health records. This is a large sample, multi-center study. The incidence of IgA nephropathy in males increased gradually with age. Age was an important factor affecting CKD. The disease was related to environment and economic status.

Berry-Phase Switch in Electrostatically Confined Topological Surface States.

Here, we visualize the trapping of topological surface states in the circular n-p junctions on the top surface of the seven-quintuple-layer three dimensional (3D) topological insulator (TI) Sb_{2}Te_{3} epitaxial films. As shown by spatially dependent and field-dependent tunneling spectra, these trapped resonances show field-induced splittings between the degenerate time-reversal-symmetric states at zero magnetic field. These behaviors are attributed unambiguously to Berry-phase switch by comparing the experimental data with both numerical and semiclassical simulations. The successful electrostatic trapping of topological surface states in epitaxial films and the observation of Berry-phase switch provide a rich platform of exploiting new ideas for TI-based quantum devices.

[An assessment of nutritional status in children on maintenance hemodialysis due to stage 5 chronic kidney disease].

OBJECTIVE: To investigate the nutritional status of children on maintenance hemodialysis due to stage 5 chronic kidney disease (CKD) and the clinical significance of nutritional assessment indices. METHODS: A total of 21 children on maintenance hemodialysis due to stage 5 CKD were grouped according to body mass index. The nutritional status was assessed based on anthropometric parameters, biochemical parameters, inflammatory factors, residual renal function, indices of dialysis adequacy, and resting energy expenditure. Related indices were compared between the children with malnutrition and those with normal nutritional status. RESULTS: Of the 21 children, 10 had malnutrition and 11 had normal nutritional status. There were significant differences between the two groups in anthropometric parameters, levels of leptin, insulin-like growth factor-1, interleukin-1, interleukin-6, and tumor necrosis factor-α, and mean 24-hour residual urine volume (P<0.05), while there were no significant differences in albumin, prealbumin, CONCLUSIONS: urea clearance index (Kt/V), and measured resting energy expenditure. CONCLUSIONS: Anthropometric parameters, biochemical parameters, residual renal function, and inflammatory factors have an important value in evaluating the nutritional status of children with stage 5 CKD on maintenance hemodialysis. Further studies are needed to investigate the value of the measurement of resting energy expenditure in the evaluation and monitoring of nutritional status in children with stage 5 CKD on maintenance hemodialysis.

Imaging the electron-boson coupling in superconducting FeSe films using a scanning tunneling microscope.

Scanning tunneling spectroscopy has been used to reveal signatures of a bosonic mode in the local quasiparticle density of states of superconducting FeSe films. The mode appears below Tc as a "dip-hump" feature at energy Ω∼4.7kBTc beyond the superconducting gap Δ. Spectra on strained regions of the FeSe films reveal simultaneous decreases in Δ and Ω. This contrasts with all previous reports on other high-Tc superconductors, where Δ locally anticorrelates with Ω. A local strong coupling model is found to reconcile the discrepancy well, and to provide a unified picture of the electron-boson coupling in unconventional superconductors.

Charge-transfer-induced cesium superlattices on graphene.

We investigate cesium (Cs) adsorption on graphene formed on a 6H-SiC(0001) substrate by a combined scanning tunneling microscopy and density functional theory study. Individual Cs atoms adsorb preferentially at the rim region of the well-defined 6×6 substrate superstructure and on multilayer graphene. By finely controlling the graphene thickness and Cs coverages (1/3 ML and 1 ML), we here demonstrate two intriguing and well-ordered Cs superlattices on bilayer and multilayer graphene (<6 layers). Statistical analysis of the Cs-Cs interatomic distance reveals a hitherto unobserved Cs-Cs long-range electrostatic potential caused by charge transfer from Cs to graphene, which couples with the inhomogeneous substrate potential to stabilize the observed Cs superlattices. The present study provides a new avenue to fabricate atomic and molecular superlattices for applications in high-density recording and data storage.

Suppression of superconductivity by twin boundaries in FeSe.

Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate twin boundaries in stoichiometric FeSe films grown by molecular beam epitaxy. Twin boundaries can be unambiguously identified by imaging the 90° change in the orientation of local electronic dimers from Fe site impurities on either side. Twin boundaries run at approximately 45° to the Fe-Fe bond directions, and noticeably suppress the superconducting gap, in contrast with the recent experimental and theoretical findings in other iron pnictides. Furthermore, vortices appear to accumulate on twin boundaries, consistent with the degraded superconductivity there. The variation in superconductivity is likely caused by the increased Se height in the vicinity of twin boundaries, providing the first local evidence for the importance of this height to the mechanism of superconductivity.

One year follow up of the outcomes of child patients with melamine-related kidney stones in Beijing and surrounding provinces in China.

AIM: To evaluate their prognosis, the damage by melamine on children's kidney and other organs, and its influence on the children's development, was investigated. METHODS: Nine hundred and sixty-two Chinese children were divided into three groups: group A, 265 children diagnosed with melamine-associated urolithiasis; group B, 197 children with a history of melamine-contaminated milk powder consumption but without urolithiasis; and group C, 500 healthy children. They were examined at 0, 1, 3, 6 and 12 months. The factors influencing the prognosis were investigated. The stone discharge was monitored by ultrasonography. Overt renal and liver damage and underlying renal injury markers were analyzed. RESULTS: The stone discharge rates 1, 3, 6 and 12 months after the diagnoses were 52.5%, 67.2%, 88.3% and 95.5%, respectively. Stone size was a stable influencing factor for the stone discharge rate. Additionally, the values of the potential renal injury markers in children with stones already discharged is equivalent to normal children. CONCLUSION: This 12 month follow up of early renal injury markers indicated that the damage to the kidney is temporary with no persistent negative outcomes being found till now. Additionally, the gross development of the children seemed not yet jeopardized by melamine. Longer-term follow up will be conducted.

Selective trapping of hexagonally warped topological surface states in a triangular quantum corral.

The surface of a three-dimensional topological insulator (TI) hosts two-dimensional massless Dirac fermions (DFs), the gapless and spin-helical nature of which leads to their high transmission through surface defects or potential barriers. Here, we report the behaviors of topological surface states (TSS) in a triangular quantum corral (TQC) which, unlike a circular corral, is supposed to be totally transparent for DFs. By real-space mapping of the electronic structure of TQCs, both the trapping and detrapping behaviors of the TSS are observed. The selection rules are found to be governed by the geometry and spin texture of the constant energy contour of TSS upon the strong hexagonal warping in Bi2Te3. Our work indicates the extended nature of TSS and elucidates the selection rules of the trapping of TSS in the presence of a complicated surface state structure, giving insights into the effective engineering of DFs in TIs.

Identification and analysis of mutations in WTX and WT1 genes in peripheral blood and tumor tissue of children with Wilms' tumor.

BACKGROUND: Wilms' tumor (nephroblastoma) is the most common pediatric kidney cancer. Only one Wilms' tumor gene is known, WT1 at 11p13, which is mutated in 5% - 10% of Wilms' tumors. Recently, mutations were reported in WTX at Xq11.1 in Wilms' tumors. This study investigated the mutation proportion, type, and distribution in WTX and WT1 in children with Wilms' tumor. The role of WTX/WT1 in the development of Wilms' tumor, and the relationship between clinical phenotype and genotype, were also studied. METHODS: Wilms' tumor specimens (blood samples from 70 patients and tumor tissue samples from 52 patients) were used. A long fragment of WTX and 10 exons and intron sequences of WT1 were amplified by polymerase chain reaction (PCR) from extracted genomic DNA and sequenced. A chi-square test compared the difference between the WTX mutation group and the no mutation group. The relationship between the mutations and clinical phenotype was analyzed. RESULTS: WTX mutations were found in 5/52 tumor tissues and in 2/70 peripheral blood samples (five cases in total, all point mutations). Two patients had a WTX mutation in both samples. WT1 mutations were found in 2/52 tumor tissues and in 4/70 peripheral blood samples (five cases in total, all point mutations). One patient had a WT1 mutation in both samples. Ten cases had WTX or WT1 mutation (19.2% of Wilms' tumors). No overlapping WTX and WT1 mutations were found. No significant differences in clinical parameters were found between patients with and without a WTX mutation. CONCLUSIONS: WTX mutations occur early in Wilms' tumor development, but at a low proportion. There was no evidence that WTX is the main cause of Wilms' tumor. Clinical parameters of patients with WTX mutations are not related to the mutation, indicating a limited impact of WTX on tumor progression. WTX and WT1 mutations occur independently, suggesting a relationship between their gene products.

Direct observation of nodes and twofold symmetry in FeSe superconductor.

We investigated the electron-pairing mechanism in an iron-based superconductor, iron selenide (FeSe), using scanning tunneling microscopy and spectroscopy. Tunneling conductance spectra of stoichiometric FeSe crystalline films in their superconducting state revealed evidence for a gap function with nodal lines. Electron pairing with twofold symmetry was demonstrated by direct imaging of quasiparticle excitations in the vicinity of magnetic vortex cores, Fe adatoms, and Se vacancies. The twofold pairing symmetry was further supported by the observation of striped electronic nanostructures in the slightly Se-doped samples. The anisotropy can be explained in terms of the orbital-dependent reconstruction of electronic structure in FeSe.

[Four new cases with WT1 gene mutations in Chinese patients with Wilms' tumor].

OBJECTIVE: Wilms' tumor (WT) is the most common malignant renal tumor in childhood. The WT1 gene located at 11p13 was identified in 1990 as a tumor suppressor gene important in the development in WT. The WT1 gene consists of 10 exons, with exons 1 to 6 encoding an N-terminal proline- and glutamine-rich transactivational domain, and exons 7 to 10 encoding a C-terminal zinc-finger domain involved in DNA binding. In China we know little about the frequency and genotype of WT1 mutations in Chinese WT patients. This study aimed to determine the frequency and genotype of WT1 mutations in children with nonsyndromic WT in China. METHODS: We collected peripheral blood of WT patients treated in Beijing Children's Hospital. Genomic DNA of 54 WT patients was isolated from blood samples. All coding WT1 exons and their flanking intronic sequences were amplified by PCR method. The amplified PCR products from all individuals were then subjected to automatic DNA sequencing. RESULTS: Four different constitutional WT1 mutations were identified in four children. Three mutations are predicted to produce truncated protein. One mutation is missense. Of the four mutations, three had not been reported before. Patient 1 had a 1006 A > T transition in exon 7, which caused (336)Lys to become a stop codon (K336X). DNA sequence analyses in patient 2 indicated the point mutations in exon 9 which was a 1168 C > T substitution and caused (390)Arg to become a stop codon (R390X). It indicated a point mutations in exon 6 in patient 3 which was a 814 G > T substitution and resulted in (272)Glu to become a stop codon (E272X). In patient 4 there was a homozygous mutation in exon 10. The mutation was a 1228 A > G substitution and resulted in (410)Ser to become a Gly codon (S410G). CONCLUSION: Constitutional WT1 mutations occur at a low frequency (7.4%) in Chinese patients with Wilms' Tumor. It is similar to the results of overseas study. Four WT1 gene mutations were confirmed, three were nonsense, one was missense.

Diagnosis and treatment of melamine-associated urinary calculus complicated with acute renal failure in infants and young children.

BACKGROUND: Infants in some areas of China developed urinary lithiasis after being fed with powdered milk that was tainted with melamine in 2008 and very small proportion of the infants developed acute renal failure caused by urinary tract calculus obstruction. The aim of this article was to summarize clinical characteristics, diagnosis and treatment of infants with urinary calculus and acute renal failure developed after being fed with melamine tainted formula milk. METHODS: Data of infant patients with urinary calculus and acute renal failure due to melamine tainted formula milk admitted to the Beijing Children's Hospital Affiliated to the Capital Medical University and the Xuzhou Children's Hospital in 2008 were used to analyze the epidemiological characteristics, clinical manifestations, imaging features as well as effects of 4 types of therapies. RESULTS: All the 34 infants with urinary calculus were complicated with acute renal failure, their blood urea nitrogen (BUN) was (24.1+/-8.2) mmol/L and creatinine (Cr) was (384.2+/-201.2) micromol/L. The chemical analysis on the urinary calculus sampled from 15 of the infants showed that the calculus contained melamine and acidum uricum. The time needed for the four types of therapies for returning Cr to normal was (3.5+/-1.9) days for cystoscopy group, (2.7+/-1.1) days for lithotomy group, (3.8+/-2.3) days for dialysis group, and (2.7+/-1.6) days for medical treatment group, which had no statistically significant difference (P=0.508). Renal failure of all the 34 infants was relieved within 1 to 7 days, averaging (3.00+/-1.78) days. CONCLUSIONS: Melamine tainted formula milk may cause urinary calculus and obstructive acute renal failure. It is suggested that firstly the patients with urinary calculus complicated with acute renal failure should be treated with dialysis or medication to correct electrolyte disturbance, in particular hyperkalemia, and then relieve the obstruction with available medical and surgical methods as soon as possible. It was observed that the short-term prognosis was satisfactory.

[Melamine related urinary calculus and acute renal failure in infants].

OBJECTIVE: To summarize clinical characteristics, diagnosis and treatment of infants with urinary calculus and acute renal failure developed after being fed with melamine tainted formula milk. METHODS: Data of infant patients with urinary calculus and acute renal failure due to melamine tainted formula milk admitted to the Beijing Children's Hospital affiliated to the Capital Medical University and the Xuzhou Children's Hospital in 2008 were used to analyze the epidemiological characteristics, clinical manifestations, image features as well as effects of 4 types of therapies. RESULTS: All the 34 infants with urinary calculus were complicated with acute renal failure, their blood urea nitrogen (BUN) was (24.1 +/- 8.2) mmol/L and creatinine (Cr) was (384.2 +/- 201.2) micromol/L. The chemical analysis on the urinary calculus sampled from 14 of the infants showed that the calculus contained melamine and acidum uricum. The time needed for the four types of therapies for returning Cr to normal was (3.5 +/- 1.9) d for cystoscopy group, (2.7 +/- 1.1) d for lithotomy group, (3.8 +/- 2.3) d for dialysis group, and (2.7 +/- 1.6) d for medical treatment group, which had no statistically significant difference (P = 0.508). Renal failure of all the 34 infants was relieved within 1 to 7 days, averaging (3.0 +/- 1.8) d. CONCLUSION: Melamine tainted formula milk may cause urinary calculus and obstructive acute renal failure. It is suggested that firstly the patients with urinary calculus complicated with acute renal failure should be treated with dialysis or medication to correct electrolyte disturbances, in particular hyperkalemia, and then relieve the obstruction with available medical and surgical methods as soon as possible. It is observed that the short term prognosis is satisfactory.