Progress in the treatment of neonatal hypoxic-ischemic encephalopathy with umbilical cord blood mononuclear cells

Neonatal hypoxic-ischemic encephalopathy (HIE) is a common disease among newborns, which is a leading cause of neonatal death and permanent neurological sequelae. Therapeutic hypothermia (TH) is the only method for the treatment of HIE that has been recognized effective clinically at home and abroad, but the efficacy is limited. Recent research suggests that the cord blood-derived mononuclear cells (CB-MNCs), which the refer to blood cells containing one nucleus in the cord blood, exert anti-oxidative, anti-inflammatory, anti-apoptotic effects and play a neuroprotective role in HIE. This review focuses on safety and efficacy, the route of administration, dose, timing and combination treatment of CB-MNCs in HIE.

[Identification and preliminary validation of potential biomarkers in the peripheral blood mononuclear cells of atopic dermatitis]

Objective: To explore the difference of peripheral blood mononuclear cells (PBMC) transcripts between atopic dermatitis (AD) and healthy controls, and to screen and preliminarily validate potential biomarkers of AD. Methods: From January 2021 to May 2022, blood samples from 9 AD patients and 10 healthy controls were collected from the Dermatology and Cosmetic Center of the Third Affiliated Hospital of Chongqing Medical University, ribonucleic acid-sequencing (RNA-seq) was used to determine the transcriptome and relative expression of PBMC, the differentially expressed genes (DEGs) were analyzed by gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction networks (PPI) analysis, and the potential biomarkers were identified by quantitative real-time PCR (qRT-PCR). Results: The age of patients in the AD group [M (Q1, Q3)] was 26.50 (22.75, 30.50) years old, and the course of disease [M (Q1, Q3)] was 15 (10, 20) years,and the age of the healthy control group [M (Q1, Q3)] was 37.00 (27.75, 40.25) years old. Compared with healthy controls, 1 044 DEGs were detected in PBMC samples in AD group, including 668 up-regulated genes and 376 down-regulated genes. Differential variable splicing (AS) showed that mutually exclusive exons (46.74%) and skipped exon (31.01%) accounted for a large proportion. GO and KEGG enrichment analysis revealed that AD is closely linked to DEGs implicated in the inflammatory response and cytokine interaction and signal pathway. Comprehensive enrichment analysis and PPI analysis selected the expression of 8 candidate genes (CCL4, CCR3, CXCR5, NFKBIA, CXCL1, IL-1B, CCL20, LY96), which was confirmed by qRT-PCR and were consistent with that of RNA-seq. Conclusions: CCL4, CCR3, CXCR5, NFKBIA, CXCL1, IL-1B, CCL20 and LY96 might be potential biomarkers of AD, participating in the occurrence and development of AD.

Estimating the individual singleton preterm birth risk: nomogram establishment and independent validation

Background

To establish and independently validate nomograms for predicting singleton preterm birth (PTB) risk based on a large sample size comprising data from two independent datasets.

Methods

This cohort study used data from 50 states and the District of Columbia in the National Vital Statistics System (NVSS) database between January 2016 and December 2020. Multivariate logistic regression analysis was used to confirm the independent risk factors for PTB. Statistically significant variables were incorporated into the logistic regression models to establish PTB prediction nomograms. The models were developed using the United States (US)-derived data and were independently validated using data from US Territories.

Results

A total of 16,294,529 mother-newborn pairs from the US were included in the training set, and 54,708 mother-newborn pairs from the US Territories were included in the validation set. In all, 4 nomograms were built: 1 to predict PTB probability, and another 3 to predict moderately and late PTB probability, very PTB probability, and extremely PTB probability, respectively. Hypertensive eclampsia and infertility treatment were found to be the top 2 contributors to PTB.

Conclusions

We developed and validated nomograms to predict the individualized probability of PTB, which could be useful to physicians for improved early identification of PTB and in making individualized clinical decisions.

T0901317, a liver X receptor agonist, ameliorates perinatal white matter injury induced by ischemia and hypoxia in neonatal rats

Perinatal white matter injury (PWMI) can lead to permanent neurological damage in preterm infants and bring a huge economic burden to their families and society. Liver X receptors (LXRs) are transcription factors that have been confirmed to mediate the myelination process under physiological conditions and are involved in regulating neurogenesis in adult animal models of acute and chronic cerebral ischemia. However, the role of LXRs in PWMI induced by both ischemic and hypoxic stimulation in the immature brain has not been reported. Herein, we investigated the role of LXRs in a neonatal rat model of white matter loss after hypoxia-ischemia (HI) injury through intraperitoneal injection of the LXR agonist T0901317 (T09) 1 day before and 15 min postinjury. The in vivo data showed that T09 treatment significantly facilitated myelination and ameliorated neurological behavior after PWMI. Moreover, T09 enhanced the proliferation of oligodendrocyte lineage cells and reduced microgliosis and astrogliosis in the microenvironment for oligodendrocytes (OLs), maintaining a healthy microenvironment for myelinating OLs. In vitro data suggested that the expression of the myelin-related genes Plp and Cnpase was increased in OLN-93 cells after T09 intervention compared with OLN-93 cells injured by oxygen and glucose deprivation (OGD). In primary mixed astrocytes/microglia cells, T09 also reduced the expression of Il6, Cox2, Tnfa and Il10 that was induced by OGD. Mechanistically, the mRNA expression level and the protein level of ATP binding cassette subfamily A member 1 (Abca1) decreased after HI injury, and the protective effect of T09 might be related to the activation of the LXRβ-ABCA1 signaling pathway. Our study revealed the protective role of LXRs in myelination and white matter homeostasis, providing a potential therapeutic option for PWMI.

Factors associated with short-term survival in neonates with hyperammonemia

BACKGROUND

Hyperammonemia due to inherited metabolic disease can lead to neurological sequelae and death in neonates. Metabolite scavenger (MS) administration and dialysis can be helpful. We aim at analyzing the factors affecting short-term survival in neonates with hyperammonemia.

METHODS

We conducted a retrospective study including all neonates with hyperammonemia admitted to the neonatal intensive care unit (NICU) of the Children's Hospital of Fudan University between April 2013 and June 2020.

RESULTS

Sixty-two neonates were enrolled in the study. Of these, 32 neonates were included in the non-survival group, and 30 neonates in the survival group. Compared to the survival group, the non-survival group had a higher peak ammonia level (882.2 vs. 433.4 µmol/L) (P=0.002), a shorter length of stay (5.7 vs. 22.3 d) (P<0.000), and higher rates of acidosis (19 vs. 10) (P=0.047), electrolyte disturbance (15 vs. 6) (P=0.033), coma (12 vs. 2) (P=0.005), and invasive mechanical ventilation (28 vs. 8) (P=0.000). A longer length of stay was the most significant protective factors in the multivariate logistic regression analysis, followed by MS administration. Factors of invasive mechanical ventilation, Δ<0 (Δ= last ammonia level - first ammonia level), coma and electrolyte disturbance established a risk score model that performed well in survival analysis. Area under ROC curve for survival length of hyperammonemia combined with peak ammonia levels was 0.737 (95% CI: 0.603-0.870).

CONCLUSIONS

MS administration is an effective treatment method for hyperammonemia in neonates, and increasing the length of stay in the NICU could help improve short-term survival. Further intervention should be administered when peak ammonia levels >406.5 µmol/L.

Src Family Kinases Inhibition Ameliorates Hypoxic-Ischemic Brain Injury in Immature Rats

Hypoxic-ischemic (HI) injury is one of the initial factors contributing to neonatal brain injury. Src family kinases (SFKs) are considered to act as molecular hubs for N-methyl-d-aspartate receptor (NMDAR) regulation and participate in the HI injury process. The objectives of this study were to evaluate the levels of phospho-Src (p-Src), the relationship between NMDARs and SFKs, and the effects of SFK inhibition on an immature rat HI brain injury model. The model was induced in 3-day-old Sprague–Dawley rats using the Rice-Vannucci model operation. The level of p-Src was evaluated using Western blotting. The association of NMDARs with SFKs was detected using Western blotting and coimmunoprecipitation. After intraperitoneal injection of 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4-d] pyrimidine (PP2), an SFK-selective inhibitor, neuropathological changes were observed by performing H&E and immunofluorescence staining, and the neurological functions were assessed using the following behavioral tests: modified neurological severity score, open field test, and Morris water maze test. The levels of p-Src first decreased at 0 h after injury, increased at 2 h after injury, and continuously decreased from 6 h to 3 days. Along with the increased p-Src levels observed at 2 h after injury, the phosphorylation of NMDAR subunit NR2B at tyrosine 1472 was increased. Following the administration of PP2, the increased p-Src and NMDAR-2B levels detected at 2 h after injury were decreased, and tissue injury and myelin basic protein expression were improved at 7 days after injury. The PP2 intervention improved the performance of injured rats on behavioral tests. In conclusion, we determined the patterns of p-Src expression after HI brain injury in immature rats and showed a relationship with the activated NMDA receptor. The inhibition of p-Src ameliorates neuropathological changes and damages neurological functions induced by HI injury.

Umbilical cord blood cells for the treatment of preterm white matter injury: Potential effects and treatment options

Preterm birth is a global public health problem. A large number of preterm infants survive with preterm white matter injury (PWMI), which leads to neurological deficits, and has multifaceted etiology, clinical course, monitoring, and outcomes. The principal upstream insults leading to PWMI initiation are hypoxia-ischemia and infection and/or inflammation and the key target cells are late oligodendrocyte precursor cells. Current PWMI treatments are mainly supportive, and thus have little effect in terms of protecting the immature brain or repairing injury to improve long-term outcomes. Umbilical cord blood (UCB) cells comprise abundant immunomodulatory and stem cells, which have the potential to reduce brain injury, mainly due to anti-inflammatory and immunomodulatory mechanisms, and also through their release of neurotrophic or growth factors to promote endogenous neurogenesis. In this review, we briefly summarize PWMI pathogenesis and pathophysiology, and the specific properties of different cell types in UCB. We further explore the potential mechanism by which UCB can be used to treat PWMI, and discuss the advantages of and potential issues related to UCB cell therapy. Finally, we suggest potential future studies of UCB cell therapy in preterm infants.

Serum galectin-3 as a biomarker for screening, early diagnosis, prognosis and therapeutic effect evaluation of pancreatic cancer

Galectin‐3 plays an important role in cell‐cell adhesion, macrophage activation, angiogenesis, metastasis and apoptosis and is overexpressed in pancreatic cancer. We explored the importance of galectin‐3 in the screening, early diagnosis, prognosis and therapeutic effect evaluation of pancreatic cancer. A time‐resolved fluorescence immunoassay was performed to detect serum galectin‐3 level. Serum samples were collected from healthy controls and patients with pancreatic cancer before and after different treatments, and the relationships between galectin‐3 level and clinical parameters were analysed. Among the healthy controls, one individual with an abnormally high concentration of galectin‐3 (9.85 μg/L) was diagnosed with pancreatic cancer. Compared to the pre‐operative level, galectin‐3 concentration significantly decreased in patients with radical excision 1 month after surgery (P < .05), but showed no obvious change in patients who underwent palliative resection. Additionally, among patients with radical excision, carcinoma recurrence rate was significantly higher in those with increased or unchanged galectin‐3 level. Retrospective analysis revealed the extraordinarily high value and high specificity of galectin‐3 for predicting 3‐year survival (P < .001). Thus, galectin‐3 may serve as a potential biomarker for the screening and early diagnosis of pancreatic cancer and as an independent prognostic indicator in patients with pancreatic cancer.

[Analysis of misdiagnosis causes of suprasellar arachnoid cysts]

Objective: To investigate the causes of misdiagnosis of suprasellar arachnoid cysts, analyze its characteristics and put forward the diagnostic basis and differential points. Methods: The clinical data fo 97 cases of suprasellar arachnoid cysts diagnosed and treated in the neurosurgery department of Beijing Tiantan Hospital and Hebei General Hospital from March 2015 to March 2019 were analyzed retrospectively. All patients underwent CT and MRI scans with obstructive hydrocephalus. 13 cases were misdiagnosed, including 7 males and 6 females. First visit age 1-31 years old, with an average age of 6.3 years. There were 10 patients younger than 6 years old. The remaining 15-year-old patients, 31-year-old patients and 26-year-old patients each have one case. 11 cases were misdiagnosed as obstructive hydrocephalus, 2 cases as cystic craniopharyngioma. Results: 13 cases were misdiagnosed and mistreated, 11 cases were treated with intraventricular and abdominal shunt, 9 cases were treated with neuroendoscopy and recovered well. One cases of intracranial hematomas underwent craniotomy again, the hematomas were removed again and the bone slise were decompressed. One case had fissured stable after shunt. There were no operative deaths and no complications in this group. After endoscopic reoperation, CT and/or MRI scans showed that the ventricle narrowed in varying degrees, some of them returned to normal size and the flow of cerebrospinal fluid (cerebrospinal fluid) was unobstruct at the end of magnetic resonance cerebrospinal fluid angiography (MRI) fistula after endoscopic reoperation. Conclusions: The incidence of suprasellar arachnoid cysts is low, it is rare in clinic and it is easy to misdiagnose and mistreate. At present, it is recognized that the best treatment methods are partial resection of endoscope cyst wall, cyst ventricle fistula and third ventricle floor fisthla.

Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd2As2

Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi-long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.

Dirac nodal surfaces and nodal lines in ZrSiS

Topological semimetals are characterized by symmetry-protected band crossings, which can be preserved in different dimensions in momentum space, forming zero-dimensional nodal points, one-dimensional nodal lines, or even two-dimensional nodal surfaces. Materials harboring nodal points and nodal lines have been experimentally verified, whereas experimental evidence of nodal surfaces is still lacking. Here, using angle-resolved photoemission spectroscopy (ARPES), we reveal the coexistence of Dirac nodal surfaces and nodal lines in the bulk electronic structures of ZrSiS. As compared with previous ARPES studies on ZrSiS, we obtained pure bulk states, which enable us to extract unambiguously intrinsic information of the bulk nodal surfaces and nodal lines. Our results show that the nodal lines are the only feature near the Fermi level and constitute the whole Fermi surfaces. We not only prove that the low-energy quasiparticles in ZrSiS are contributed entirely by Dirac fermions but also experimentally realize the nodal surface in topological semimetals.

Using changes in pro-brain natriuretic peptide of plasma amino-terminal and norepinephrine levels as prognostic and diagnostic factors in hand-foot-and-mouth disease

OBJECTIVE

We explored the possibility of using the variations in the pro-brain natriuretic peptide (NT-proBNP) of serum amino-terminal and norepinephrine (NE) levels as prognostic as well as diagnostic factors in children suffering from severe hand-foot-and-mouth disease (HFMD).

PATIENTS AND METHODS

From February 2014 to February 2015, 102 HFMD patients were enrolled in this study. They were divided into the common group (n=55) and the severe group (n=47). During the same period, 30 healthy children were enrolled in the control group. NT-proBNP and NE levels were evaluated in all patients.

RESULTS

Our results revealed that NT-proBNP and NE levels in the common group were not evidently different compared with those of the control group. However, these levels in the severe group were significantly higher than other groups. After treatment, NT-proBNP and NE levels in the severe group were lower than those measured before treatment.

CONCLUSIONS

We suggest that serum level of NT-proBNP can be used as a valuable index to judge the severity of HFMD and to predict the prognosis. We believe that NT-proBNP and NE levels can be added to other HFMD diagnostic tools.

Anatomic Location of Tumor Predicts the Accuracy of Motor Function Localization in Diffuse Lower-Grade Gliomas Involving the Hand Knob Area

BACKGROUND AND PURPOSE

The accuracy of preoperative blood oxygen level-dependent fMRI remains controversial. This study assessed the association between the anatomic location of a tumor and the accuracy of fMRI-based motor function mapping in diffuse lower-grade gliomas.

MATERIALS AND METHODS

Thirty-five patients with lower-grade gliomas involving motor areas underwent preoperative blood oxygen level-dependent fMRI scans with grasping tasks and received intraoperative direct cortical stimulation. Patients were classified into an overlapping group and a nonoverlapping group, depending on the extent to which blood oxygen level-dependent fMRI and direct cortical stimulation results concurred. Tumor location was quantitatively measured, including the shortest distance from the tumor to the hand knob and the deviation distance of the midpoint of the hand knob in the lesion hemisphere relative to the midline compared with the normal contralateral hemisphere.

RESULTS

A 4-mm shortest distance from the tumor to the hand knob value was identified as optimal for differentiating the overlapping and nonoverlapping group with the receiver operating characteristic curve (sensitivity, 84.6%; specificity, 77.8%). The shortest distances from the tumor to the hand knob of ≤4 mm were associated with inaccurate fMRI-based localizations of the hand motor cortex. The shortest distances from the tumor to the hand knob were larger (P = .002), and the deviation distances for the midpoint of the hand knob in the lesion hemisphere were smaller (P = .003) in the overlapping group than in the nonoverlapping group.

CONCLUSIONS

This study suggests that the shortest distance from the tumor to the hand knob and the deviation distance for the midpoint of the hand knob on the lesion hemisphere are predictive of the accuracy of blood oxygen level-dependent fMRI results. Smaller shortest distances from the tumor to the hand knob and larger deviation distances for the midpoint of hand knob on the lesion hemisphere are associated with less accuracy of motor cortex localization with blood oxygen level-dependent fMRI. Preoperative fMRI data for surgical planning should be used cautiously when the shortest distance from the tumor to the hand knob is ≤4 mm, especially for lower-grade gliomas anterior to the central sulcus.

Electronic structure of SrSn2As2 near the topological critical point

Topological materials with exotic quantum properties are promising candidates for quantum spin electronics. Different classes of topological materials, including Weyl semimetal, topological superconductor, topological insulator and Axion insulator, etc., can be connected to each other via quantum phase transition. For example, it is believed that a trivial band insulator can be twisted into topological phase by increasing spin-orbital coupling or changing the parameters of crystal lattice. With the results of LDA calculation and measurement by angle-resolved photoemission spectroscopy (ARPES), we demonstrate in this work that the electronic structure of SrSn₂As₂ single crystal has the texture of band inversion near the critical point. The results indicate the possibility of realizing topological quantum phase transition in SrSn₂As₂ single crystal and obtaining different exotic quantum states.

Comparison between anti-VEGF therapy and corticosteroid or laser therapy for macular oedema secondary to retinal vein occlusion: A meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Therapeutic effects of anti-VEGF agents, corticosteroids and laser therapy have been previously examined for treating macular oedema secondary to branch and central retinal vein occlusion (BRVO and CRVO). However, anti-VEGF efficacy has not been previously compared to corticosteroid or laser therapy efficacy. We performed a meta-analysis to compare these treatments.

METHODS

Pertinent publications were identified through comprehensive literature searches. Therapeutic effects were estimated using best-corrected visual acuity (BCVA), central retinal thickness (CRT) and intraocular pressure (IOP). The Review Manager (version 5.3.5) was used to perform searches.

RESULTS AND DISCUSSION

Eleven randomized, controlled trials that included 1045 RVO patients were identified. For eyes with BRVO, anti-VEGF therapy improved BCVA significantly more than corticosteroid/laser therapy at 3 (P=.0002), 6 (P<.00001) and 12 months (P<.00001). For eyes with CRVO, this difference was only significant at 6 months (P=.002). The same was true when efficacy was examined using CRT at 3 and 6 months (BRVO: both P<.00001, CRVO 6 months: P=.02). Long-term efficacy of anti-VEGF agents was limited in eyes with BRVO and CRVO. Improvements in BCVA were similar at 1 and 3 months (P=.74), but BCVA decreased between 3 and 6 months (P=.03). In contrast, BCVA progressively decreased 1 and 6 months following corticosteroid/laser therapy (both P<.00001). Lastly, eyes that had been treated with anti-VEGF agents had significantly lower IOP changes than eyes treated with corticosteroids/laser 3 and 6 months after initiating therapy (both P<.00001).

WHAT IS NEW AND CONCLUSION

Anti-VEGF agents improve BCVA and reduce CRT more effectively and longer than corticosteroid/laser in eyes with RVO. Anti-VEGF agents also have a lower risk of elevating IOP. Additionally, anti-VEGF agents are more effective for treating BRVO than CRVO.

Enhanced superconductivity accompanying a Lifshitz transition in electron-doped FeSe monolayer

The origin of enhanced superconductivity over 50 K in the recently discovered FeSe monolayer films grown on SrTiO₃ (STO), as compared to 8 K in bulk FeSe, is intensely debated. As with the ferrochalcogenides A_xFe_2−ySe₂ and potassium-doped FeSe, which also have a relatively high-superconducting critical temperature (T_c), the Fermi surface (FS) of the FeSe/STO monolayer films is free of hole-like FS, suggesting that a Lifshitz transition by which these hole FSs vanish may help increasing T_c. However, the fundamental reasons explaining this increase of T_c remain unclear. Here we report a 15 K jump of T_c accompanying a second Lifshitz transition characterized by the emergence of an electron pocket at the Brillouin zone centre, which is triggered by high-electron doping following in situ deposition of potassium on FeSe/STO monolayer films. Our results suggest that the pairing interactions are orbital dependent in generating enhanced superconductivity in FeSe.

The origin of superconductivity enhancement in FeSe monolayer grown on SrTiO₃ compared to bulk FeSe is still a debated issue. Here, Shi et al. report a further 15 K jump of T_c accompanying a second Lifshitz transition triggered by electron doping in FeSe/SrTiO₃ monolayer films.

[Analysis of clinical characteristics of necrotizing enterocolitis in term infants]

OBJECTIVE

To investigate the characteristics and outcomes of necrotizing enterocolitis (NEC) in Chinese term infants population.

METHODS

A national neonatal necrotizing enterocolitis network was established. Neonates as having necrotizing enterocolitis with gestation age ≥37 weeks were identified if they met the accepted diagnostic criterion during the study period from Jan 1(st) 2011 to Dec 31(st) 2011. The data of maternal and neonates' characteristics, the comorbidities, the clinical interventions prior to NEC, the clinical courses and radiology results, the medical and surgical treatment and the outcomes were collected. SPSS 19.0 software was used to do statistic analysis. Logistic-regression models were used to analyze the risk factors for death in infants with NEC, odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

There were 231 067 newborn infants, 164 307 of them were term infants, admitted to 95 hospitals in main land China. There were 718 term infants were diagnosed as necrotizing enterocolitis with the incidence of 0.44%. There were 294 term infants cases identified as ≥stage 2 necrotizing enterocolitis for the analysis, including 193 cases of stage 2 and 101 cases of stage 3.The mean gestation age was (39.0±1.3) weeks, and the mean birth weight was(3 087.4±548.3)g. The percentage of small for gestation age was 20.4%. The onset age of NEC was 5 (2-11)d. The percentage of cases received breast milk feeding was 23.7%. The most common comorbidities were sepsis (9.5%, 28/294), asphyxia (9.5%, 28/294), pneumonia (7.8%, 23/294) and congenital megacolon (7.5%, 22/294). The bowel perforation rate was 13.9%. The rate of cases who received surgical treatment was 25.2%(76.6% small intestinal necrosis and 65.8% small intestinal perforation). The mortality rate was 28.9%(the mortality rate were 20.7% and 44.6% in stage 2 and stage 3 NEC, respectively). Noninvasive continuous positive airway pressure treatment for NEC (OR=5.278, 95% CI: 2.058-13.533, P<0.01) and NEC staging 3 (OR=3.156, 95% CI: 1.766-5.642, P<0.01) were statistically significantly associated with mortality of NEC.

CONCLUSIONS

The term infants with necrotizing enterocolitis usually have the underlying comorbidities. The breastmilk feeding rate is low. Necrotizing enterocolitis remains high mortality in term neonates in Chinese neonatal units. Noninvasive continuous positive airway pressure treatment for NEC is statistically significantly associated with mortality of NEC.

Distinct Evolutions of Weyl Fermion Quasiparticles and Fermi Arcs with Bulk Band Topology in Weyl Semimetals

The Weyl semimetal phase is a recently discovered topological quantum state of matter characterized by the presence of topologically protected degeneracies near the Fermi level. These degeneracies are the source of exotic phenomena, including the realization of chiral Weyl fermions as quasiparticles in the bulk and the formation of Fermi arc states on the surfaces. Here, we demonstrate that these two key signatures show distinct evolutions with the bulk band topology by performing angle-resolved photoemission spectroscopy, supported by first-principles calculations, on transition-metal monophosphides. While Weyl fermion quasiparticles exist only when the chemical potential is located between two saddle points of the Weyl cone features, the Fermi arc states extend in a larger energy scale and are robust across the bulk Lifshitz transitions associated with the recombination of two nontrivial Fermi surfaces enclosing one Weyl point into a single trivial Fermi surface enclosing two Weyl points of opposite chirality. Therefore, in some systems (e.g., NbP), topological Fermi arc states are preserved even if Weyl fermion quasiparticles are absent in the bulk. Our findings not only provide insight into the relationship between the exotic physical phenomena and the intrinsic bulk band topology in Weyl semimetals, but also resolve the apparent puzzle of the different magnetotransport properties observed in TaAs, TaP, and NbP, where the Fermi arc states are similar.

Engineering the Structural and Electronic Phases of MoTe2 through W Substitution

MoTe₂ is an exfoliable transition metal dichalcogenide (TMD) that crystallizes in three symmetries: the semiconducting trigonal-prismatic 2H- or α-phase, the semimetallic and monoclinic 1T^'- or β-phase, and the semimetallic orthorhombic γ-structure. The 2H-phase displays a band gap of ∼1 eV making it appealing for flexible and transparent optoelectronics. The γ-phase is predicted to possess unique topological properties that might lead to topologically protected nondissipative transport channels. Recently, it was argued that it is possible to locally induce phase-transformations in TMDs, through chemical doping, local heating, or electric-field to achieve ohmic contacts or to induce useful functionalities such as electronic phase-change memory elements. The combination of semiconducting and topological elements based upon the same compound might produce a new generation of high performance, low dissipation optoelectronic elements. Here, we show that it is possible to engineer the phases of MoTe₂ through W substitution by unveiling the phase-diagram of the Mo_1-xW_xTe₂ solid solution, which displays a semiconducting to semimetallic transition as a function of x. We find that a small critical W concentration x_c ∼ 8% stabilizes the γ-phase at room temperature. This suggests that crystals with x close to x_c might be particularly susceptible to phase transformations induced by an external perturbation, for example, an electric field. Photoemission spectroscopy, indicates that the γ-phase possesses a Fermi surface akin to that of WTe₂.

Topologically Entangled Rashba-Split Shockley States on the Surface of Grey Arsenic

We discover a pair of spin-polarized surface bands on the (111) face of grey arsenic by using angle-resolved photoemission spectroscopy (ARPES). In the occupied side, the pair resembles typical nearly-free-electron Shockley states observed on noble-metal surfaces. However, pump-probe ARPES reveals that the spin-polarized pair traverses the bulk band gap and that the crossing of the pair at Γ[over ¯] is topologically unavoidable. First-principles calculations well reproduce the bands and their nontrivial topology; the calculations also support that the surface states are of Shockley type because they arise from a band inversion caused by crystal field. The results provide compelling evidence that topological Shockley states are realized on As(111).

Improving the Grading Accuracy of Astrocytic Neoplasms Noninvasively by Combining Timing Information with Cerebral Blood Flow: A Multi-TI Arterial Spin-Labeling MR Imaging Study

BACKGROUND AND PURPOSE

Systematic and accurate glioma grading has clinical significance. We present the utility of multi-TI arterial spin-labeling imaging and provide the bolus arrival time maps for grading astrocytomas.

MATERIALS AND METHODS

Forty-three patients with astrocytomas (21 men; mean age, 51 years) were recruited. The classification abilities of conventional MR imaging features, normalized CBF value derived from multi-TI arterial spin-labeling imaging, normalized bolus arrival time, and normalized CBF derived from single-TI arterial spin-labeling were compared in patients with World Health Organization (WHO) grade II, III, and IV astrocytomas.

RESULTS

The normalized CBF value derived from multi-TI arterial spin-labeling imaging was higher in patients with higher grade astrocytoma malignancies compared with patients with lower grade astrocytomas, while the normalized bolus arrival time showed the opposite tendency. The normalized CBF value derived from the multi-TI arterial spin-labeling imaging showed excellent performance with areas under the receiver operating characteristic curve of 0.813 (WHO II versus III), 0.964 (WHO II versus IV), 0.872 (WHO III versus IV), and 0.883 (low-grade-versus-high-grade gliomas). The normalized CBF value derived from single-TI arterial spin-labeling imaging could statistically differentiate the WHO II and IV groups (area under the receiver operating characteristic curve = 0.826). The normalized bolus arrival time effectively identified the WHO grades II and III with an area under the receiver operating characteristic curve of 0.836. Combining the normalized CBF value derived from multi-TI arterial spin-labeling imaging and normalized bolus arrival time improved the diagnostic accuracy from 65.10% to 72.10% compared with the normalized CBF value derived from multi-TI arterial spin-labeling imaging being applied independently. The combination of multi-TI arterial spin-labeling imaging and conventional MR imaging had the best performance, with a diagnostic accuracy of 81.40%.

CONCLUSIONS

Multi-TI arterial spin-labeling imaging can evaluate perfusion dynamics by combining normalized bolus arrival time and normalized CBF values derived from multiple TIs. It is superior to single-TI arterial spin-labeling imaging and conventional MR imaging features when applied independently and can improve the diagnostic accuracy when combined with conventional MR imaging for grading astrocytomas.

Compensated Semimetal LaSb with Unsaturated Magnetoresistance

By combining angle-resolved photoemission spectroscopy and quantum oscillation measurements, we performed a comprehensive investigation on the electronic structure of LaSb, which exhibits near-quadratic extremely large magnetoresistance (XMR) without any sign of saturation at magnetic fields as high as 40 T. We clearly resolve one spherical and one intersecting-ellipsoidal hole Fermi surfaces (FSs) at the Brillouin zone (BZ) center Γ and one ellipsoidal electron FS at the BZ boundary X. The hole and electron carriers calculated from the enclosed FS volumes are perfectly compensated, and the carrier compensation is unaffected by temperature. We further reveal that LaSb is topologically trivial but shares many similarities with the Weyl semimetal TaAs family in the bulk electronic structure. Based on these results, we have examined the mechanisms that have been proposed so far to explain the near-quadratic XMR in semimetals.

[Incidence and influencing factors of term small for gestational age infants in China]

OBJECTIVE

To investigate the incidence and influencing factors of term small for gestational age infants (SGA ) in China.

METHODS

This study is a multicenter study. Data were collected from Chinese Neonatal Network with term infants, born from May 1st 2010 to February 28th 2014, from 83 nationwide hospitals.

RESULTS

A total of 170 565 neonates were recorded from 83 nationwide hospitals; 144 659 cases were term newborn, and 3 543 neonates were found to be term SGA. The incidence of term SGA was 2.45%. In term SGA, the girl's incidence (2.88%, 1 985/69 003) was higher than boy (2.05%, 1 531/74 707), P<0.001. Furthermore, the incidence of in vitro fertilization (IVF) and artificial fertilization of term SGA was 9.12% (66/724), which was higher than the natural conception (2.42%, 3 465/143 283), P<0.001. The incidence of term SGA in multiple births (30.37%, 741/2 440) was higher than that of single birth (1.97%, 2 787/141 366), P<0.001. The incidence of SGA with maternal age <18 years old was 4.86% (27/556) and was 3.20% (307/9 592) with maternal age > 35 years old, meanwhile both were higher than that with maternal age as 18-35 years old (2.39%, 3 197/133 662). The incidence of SGA with maternal occupation as farmers was 4.67% (854/18 284), which was significantly higher than other professions. The incidence of SGA with maternal education as illiterate and elementary education was 8.65% (187/2 162), 5.17% (397/7 678), respectively, both were significantly higher than those with mother graduated from university (1.72%, 853/49 692). Moreover, the geographical distribution of the main residence of the term SGA mothers showed Northeast Area (1.54%, 30/1 946)and East Area (2.21%, 1 267/57 334) had lower incidence of term SGA than those of Central South Area (2.71%, 493/18 223) and Southwest Area (3.67%, 876/23 852).

CONCLUSIONS

The incidence of term SGA was 2.45% in this study, which was influenced significantly by gender, IVF, multiple births, maternal factors (age, maternal occupation, level of education) and geographical distribution. This multicenter study with large data, to a certain extent, reflected status of the incidence and influencing factors of term SGA in China, which will help prevent and treat term SGA.

[Incidence and influencing factors of term small for gestational age infants in China]

OBJECTIVE

To investigate the incidence and influencing factors of term small for gestational age infants (SGA ) in China.

METHODS

This study is a multicenter study. Data were collected from Chinese Neonatal Network with term infants, born from May 1st 2010 to February 28th 2014, from 83 nationwide hospitals.

RESULTS

A total of 170 565 neonates were recorded from 83 nationwide hospitals; 144 659 cases were term newborn, and 3 543 neonates were found to be term SGA. The incidence of term SGA was 2.45%. In term SGA, the girl's incidence (2.88%, 1 985/69 003) was higher than boy (2.05%, 1 531/74 707), P<0.001. Furthermore, the incidence of in vitro fertilization (IVF) and artificial fertilization of term SGA was 9.12% (66/724), which was higher than the natural conception (2.42%, 3 465/143 283), P<0.001. The incidence of term SGA in multiple births (30.37%, 741/2 440) was higher than that of single birth (1.97%, 2 787/141 366), P<0.001. The incidence of SGA with maternal age <18 years old was 4.86% (27/556) and was 3.20% (307/9 592) with maternal age > 35 years old, meanwhile both were higher than that with maternal age as 18-35 years old (2.39%, 3 197/133 662). The incidence of SGA with maternal occupation as farmers was 4.67% (854/18 284), which was significantly higher than other professions. The incidence of SGA with maternal education as illiterate and elementary education was 8.65% (187/2 162), 5.17% (397/7 678), respectively, both were significantly higher than those with mother graduated from university (1.72%, 853/49 692). Moreover, the geographical distribution of the main residence of the term SGA mothers showed Northeast Area (1.54%, 30/1 946)and East Area (2.21%, 1 267/57 334) had lower incidence of term SGA than those of Central South Area (2.71%, 493/18 223) and Southwest Area (3.67%, 876/23 852).

CONCLUSIONS

The incidence of term SGA was 2.45% in this study, which was influenced significantly by gender, IVF, multiple births, maternal factors (age, maternal occupation, level of education) and geographical distribution. This multicenter study with large data, to a certain extent, reflected status of the incidence and influencing factors of term SGA in China, which will help prevent and treat term SGA.

Observation of Fermi-Arc Spin Texture in TaAs

We have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin polarized. The measured spin texture fulfills the requirement of mirror and time-reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first-principles calculations.

ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism

Its direct momentum sensitivity confers to angle-resolved photoemission spectroscopy (ARPES) a unique perspective in investigating the superconducting gap of multi-band systems. In this review we discuss ARPES studies on the superconducting gap of high-temperature Fe-based superconductors. We show that while Fermi-surface-driven pairing mechanisms fail to provide a universal scheme for the Fe-based superconductors, theoretical approaches based on short-range interactions lead to a more robust and universal description of superconductivity in these materials. Our findings are also discussed in the broader context of unconventional superconductivity.

Correlation-induced self-doping in the iron-pnictide superconductor Ba2Ti2Fe2As4O

The electronic structure of the iron-based superconductor Ba2Ti2Fe2As4O (Tc(onset)=23.5  K) has been investigated by using angle-resolved photoemission spectroscopy and combined local density approximation and dynamical mean field theory calculations. The electronic states near the Fermi level are dominated by both the Fe 3d and Ti 3d orbitals, indicating that the spacer layers separating different FeAs layers are also metallic. By counting the enclosed volumes of the Fermi surface sheets, we observe a large self-doping effect; i.e., 0.25 electrons per unit cell are transferred from the FeAs layer to the Ti2As2O layer, leaving the FeAs layer in a hole-doped state. This exotic behavior is successfully reproduced by our dynamical mean field calculations, in which the self-doping effect is attributed to the electronic correlations in the 3d shells. Our work provides an alternative route of effective doping without element substitution for iron-based superconductors.

Gene expression profiling of Duchenne muscular dystrophy reveals characteristics along disease progression

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy with no cure currently available. In this study, using two microarray data sets obtained from the Gene Expression Omnibus database, we conducted a dysfunctional pathway-enrichment analysis and investigated deregulated genes that are specific to different phases of the disease in order to determine pathogenic characteristics in the progression of DMD. We identified 41 and 33 dysfunctional pathways that were enriched with differentially expressed genes in presymptomatic patients and in symptomatic patients, respectively. Over 70% of pathways were shared between both phases and many of them involved the inflammatory process, suggesting that inflammatory cascades were induced soon after the birth of the patients. Further investigation showed that presymptomatic patients performed better with respect to muscle regeneration and cardiac muscle calcium homeostasis maintenance. Neuronal nitric oxide synthase, dihydropyridine receptors, sarcoplasmic/endoplasmic reticulum calcium ATPase, and phospholamban may serve as potential targets for further molecular diagnostic tests. Our results may provide a better understanding for the treatment of DMD.

Angle-resolved photoemission spectroscopy observation of anomalous electronic states in EuFe2As(2-x)P(x)

We used angle-resolved photoemission spectroscopy to investigate the electronic structure and the Fermi surface of EuFe2As2, EuFe2As1.4P0.6 and EuFe2P2. We observed doubled core level peaks associated with the pnictide atoms. Using K atoms evaporated at the surface to affect the surface quality, we show that one component of these doubled peaks is related to a surface state. Nevertheless, strong electronic dispersion along the c-axis, especially pronounced in EuFe2P2, is observed for at least one band, thus indicating that the Fe states, albeit probably affected at the surface, do not form pure two-dimensional surface states. We determine the evolution of the Fermi surface as a function of the P content and reveal that the hole Fermi surface pockets enlarge with increasing P content. We also show that the spectral weight near the Fermi level of EuFe2P2 is reduced as compared to that of EuFe2As2 and EuFe2As1.4P0.6. Finally, we identify the electronic states associated with the Eu(2+) f states and show an anomalous jump in EuFe2P2.

Three dimensionality and orbital characters of the Fermi surface in (Tl,Rb)(y)Fe(2-x)Se2

We report a comprehensive angle-resolved photoemission spectroscopy study of the tridimensional electronic bands in the recently discovered Fe selenide superconductor ((Tl,Rb)(y)Fe(2-x)Se2 (T(c)=32  K). We determined the orbital characters and the k(z) dependence of the low energy electronic structure by tuning the polarization and the energy of the incident photons. We observed a small 3D electron Fermi surface pocket near the Brillouin zone center and a 2D like electron Fermi surface pocket near the zone boundary. The photon energy dependence, the polarization analysis and the local-density approximation calculations suggest a significant contribution from the Se 4p(z) and Fe 3d(xy) orbitals to the small electron pocket. We argue that the emergence of Se 4p(z) states might be the cause of the different magnetic properties between Fe chalcogenides and Fe pnictides.

Absence of a holelike fermi surface for the iron-based K0.8F1.7Se2 superconductor revealed by angle-resolved photoemission spectroscopy

We have performed an angle-resolved photoemission spectroscopy study of the new iron-based superconductor K(0.8)Fe(1.7)Se(2) (T(c)∼30 K). Clear band dispersion is observed with the overall bandwidth renormalized by a factor of 2.5 compared to our local density approximation calculations, indicating relatively strong correlation effects. Only an electronlike band crosses the Fermi energy, forming a nearly circular Fermi surface (FS) at M (π, 0). The holelike band at Γ sinks ∼90 meV below the Fermi energy, with an indirect band gap of 30 meV, to the bottom of the electronlike band. The observed FS topology in this superconductor favors (π, π) inter-FS scattering between the electronlike FSs at the M points, in sharp contrast to other iron-based superconductors which favor (π, 0) inter-FS scattering between holelike and electronlike FSs.

A precise method for visualizing dispersive features in image plots

In order to improve the advantages and the reliability of the second derivative method in tracking the position of extrema from experimental curves, we develop a novel analysis method based on the mathematical concept of curvature. We derive the formulas for the curvature in one and two dimensions and demonstrate their applicability to simulated and experimental angle-resolved photoemission spectroscopy data. As compared to the second derivative, our new method improves the localization of the extrema and reduces the peak broadness for a better visualization on intensity image plots.

Angle-resolved photoemission spectroscopy of the iron-chalcogenide superconductor Fe1.03Te0.7Se0.3: strong coupling behavior and the universality of interband scattering

We have performed angle-resolved photoemission spectroscopy of the iron-chalcogenide superconductor Fe1.03Te0.7Se0.3 to investigate the electronic structure relevant to superconductivity. We observed a holelike Fermi surface (FS) and an electronlike FS at the Brillouin zone center and corner, respectively, which are nearly nested by the Q∼(π,π) wave vector. We do not find evidence for the nesting instability with Q∼(π+δ,0) reminiscent of the antiferromagnetic order in the parent compound Fe1+yTe. We have observed an isotropic superconducting (SC) gap along the holelike FS with the gap size Δ of ∼4 meV (2Δ/kBTc ∼ 7), demonstrating the strong-coupling superconductivity. The observed similarity of low-energy electronic excitations between iron-chalcogenides and iron-arsenides strongly suggests that common interactions which involve Q∼(π,π) scattering are responsible for the SC pairing.

The influence of donor specific vertebral body derived bone marrow cell infusion on canine islet allograft survival without irradiation conditioning of the recipient

In recent studies in rodents, it was shown, that donor specific tolerance towards islet allografts without irradiation therapy of the recipient is induced by bone marrow cell infusion in combination with temporary immunosuppression. In the present study, the effect of donor specific bone marrow cell (DBMC) infusion at the time of intrahepatic islet allotransplantation without irradiation conditioning of the recipient was investigated in the canine model, paralleling ongoing clinical trials. It was observed, that unfractionated bone marrow cells given simultaneous to islet allografts led to higher frequencies of rejection periods and decreased islet allograft survival, when administered to recipients immunosuppressed with Cyclosporine A only. In contrast, an additional short inductive treatment of the recipient with an anti-dog-T-lymphocyte monoclonal antibody (5G2) abrogated the enhanced immunogenicity of the unfractionated bone marrow preparation, prolonging islet allograft survival with no rejection episodes observed during the immunosuppressive treatment with Cyclosporine. The composition of bone marrow cells might have contributed to the higher immunogenicity, since the percentage of MHC-class II antigen bearing cells is similar to man, but significantly higher than compared to rodents. It is therefore suggested, that further studies should encompass both timing of bone marrow cell infusion, appropriate immunosuppression and strategies to functionally inactivate mature MHC-class-II positive cells prior to DBMC infusion.

Search for Lorentz and CPT violation effects in Muon spin precession

The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero delta omega a(=omega a mu+ - omega a mu-) and a sidereal variation of omega a mu+/-). No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ = -(1.0+/-1.1) x 10(-23) GeV; (m mu dZ0 + HXY)=(1.8+/-6.0) x 10(-23) GeV; and the 95% confidence level limits b perpendicular mu+ <1.4 x 10(-24) GeV and b perpendicular mu- <2.6 x 10(-24) GeV.

Rapid recovery of segmental neurological function in a tetraplegic patient following transplantation of fetal olfactory bulb-derived cells

STUDY DESIGN

Case report.

OBJECTIVE

Report rapid neurological changes in a complete tetraplegic following a cell injection procedure.

SETTING

Beijing, China.

METHODS

ASIA/IMSOP neurological scale. Immunostaining of cell cultures. Cellular transplantation to effect functional restoration following spinal cord injury (SCI) has been hypothesized to cause improvements through axonal regeneration, increased plasticity, or axonal remyelination. Several human trials are in preliminary phases. We report a rapid improvement in motor and sensory functions in the segment adjacent to the level of complete SCI within days following cellular transplantation of cultured fetal olfactory bulb-derived cells. The patient was an 18-year-old C3 ASIA A complete tetraplegic 18 months post-injury who had been neurologically stable for more than 6 months.

RESULTS

Within 48 h of cell transplantation, the patient improved one ASIA motor grade in the left elbow flexors and began to show right wrist extensor function. Descent of the sensory level occurred within 4 days and then the rate of change slowed. He is now a C5 motor and C4 sensory complete tetraplegic. Cellular cultures prepared in the same facility showed viable human cells that labeled for nestin and GFAP.

CONCLUSION

We hypothesize that improved transmission in intact fibers subserving the zone of partial preservation accounts for these early improvements. We emphasize the need for further independent analysis of the outcomes of this and other preliminary cell transplant studies.

High-dose methylprednisolone may cause myopathy in acute spinal cord injury patients

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Although Bracken et al have demonstrated a significant neuroprotective effect of high-dose intravenous (i.v.) methylprednisolone (MP) within 8 h post spinal cord injury (SCI), this practice has recently been challenged. We hypothesized it is possible that acute corticosteroid myopathy (ACM) may occur secondary to the MP. This pilot study was performed to test this hypothesis.

SETTING

University of Miami School of Medicine/Jackson Memorial Hospital, Miami VA Medical Center, FL, USA.

METHODS

Subjects included five nonpenetrating traumatic SCI patients, who received 24 h MP according to National Acute Spinal Cord Injury Studies (NASCIS) protocol, and three traumatic patients who suffered SCI and did not receive MP. Muscle biopsies and electromyography (EMG) were performed to determine if myopathic changes existed in these patients.

RESULTS

Muscle biopsies from the SCI patients who received 24 h of MP showed muscle damage consistent with ACM in four out of five cases. EMG studies demonstrated myopathic changes in the MP-treated patients. In the three patients who had SCI but did not receive MP, muscle biopsies were normal and EMGs did not reveal evidence of myopathy.

CONCLUSION

Our data suggest that MP in the dose recommended by the NASCIS may cause ACM. If this is true, part of the improvement of neurological recovery showed in NASCIS may be only a recording of the natural recovery of ACM, instead of any protection that MP offers to the injured spinal cord.

Measurement of the negative muon anomalous magnetic moment to 0.7 ppm

The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 ppm (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement for the negative muon. The result a(mu(-))=11 659 214(8)(3) x 10(-10) (0.7 ppm), where the first uncertainty is statistical and the second is systematic, is consistent with previous measurements of the anomaly for the positive and the negative muon. The average of the measurements of the muon anomaly is a(mu)(exp)=11 659 208(6) x 10(-10) (0.5 ppm).

Coexpression of complementary fragments of ClC-5 and restoration of chloride channel function in a Dent's disease mutation

The human hereditary disorder Dent's disease is linked to loss-of-function mutations of the chloride channel ClC-5. Many of these mutations involve insertion of premature stop codons, resulting in truncation of the protein. We determined whether the functional activity of ClC-5 could be restored by coexpression of the truncated protein (containing the NH2-terminal region) with its complementary “missing” COOH-terminal region. Split channel constructs for ClC-5, consisting of complementary N and C protein regions, were created at an arbitrary site in the COOH-terminal region (V655) and at four Dent's disease mutation sites (R347, Y617, R648, and R704). Coexpression of complementary fragments for the split channel at V655 produced currents with anion and pH sensitivity similar to those of wild-type ClC-5. Channel activity was similarly restored when complementary split channel constructs made for Dent's mutation R648 were coexpressed, but no ClC-5 currents were found when split channels for mutations R347, Y617, or R704 were coexpressed. Immunoblot and immunofluorescence studies of COS-7 cells revealed that N or C protein fragments could be transiently expressed and detected in the plasma membrane, even in split channels that failed to show functional activity. The results suggest that ClC-5 channel activity can be restored for specific Dent's mutations by expression of the missing portion of the ClC-5 molecule.

Role of the mitochondrial permeability transition in apoptotic and necrotic death after ischemia/reperfusion injury to hepatocytes

Reperfusion of ATP-depleted tissues after warm or cold ischemia causes pH-dependent necrotic and apoptotic cell death. In hepatocytes and other cell types as well, the mechanism underlying this reperfusion-induced cell death involves onset of the mitochondrial permeability transition (MPT). Opening of permeability transition (PT) pores in the mitochondrial inner membrane initiates the MPT, an event blocked by cyclosporin A (CsA) and pH less than 7.4. Thus, both acidotic pH and CsA prevent MPT-dependent reperfusion injury. Glycine also blocks reperfusion-induced necrosis but acts downstream of PT pore opening by stabilizing the plasma membrane. After the MPT, ATP availability from glycolysis or other source determines whether cell injury after reperfusion progresses to ATP depletion-dependent necrosis or ATP-requiring apoptosis. Thus, apoptosis and necrosis after reperfusion share a common pathway, the MPT. Cell injury progressing to either necrosis or apoptosis by shared pathways can be more aptly termed necrapoptosis.