In vivo assembly enhanced binding effect augments tumor specific ferroptosis therapy

Emerging evidence indicates that the activation of ferroptosis by glutathione peroxidase 4 (GPX4) inhibitors may be a prominent therapeutic strategy for tumor suppression. However, the wide application of GPX4 inhibitors in tumor therapy is hampered due to poor tumor delivery efficacy and the nonspecific activation of ferroptosis. Taking advantage of in vivo self-assembly, we develop a peptide-ferriporphyrin conjugate with tumor microenvironment specific activation to improve tumor penetration, endocytosis and GPX4 inhibition, ultimately enhancing its anticancer activity via ferroptosis. Briefly, a GPX4 inhibitory peptide is conjugated with an assembled peptide linker decorated with a pH-sensitive moiety and ferriporphyrin to produce the peptide-ferriporphyrin conjugate (Gi-F-CAA). Under the acidic microenvironment of the tumor, the Gi-F-CAA self-assembles into large nanoparticles (Gi-F) due to enhanced hydrophobic interaction after hydrolysis of CAA, improving tumor endocytosis efficiency. Importantly, Gi-F exhibits substantial inhibition of GPX4 activity by assembly enhanced binding (AEB) effect, augmenting the oxidative stress of ferriporphyrin-based Fenton reaction, ultimately enabling antitumor properties in multiple tumor models. Our findings suggest that this peptide-ferriporphyrin conjugate design with AEB effect can improve the therapeutic effect via induction of ferroptosis, providing an alternative strategy for overcoming chemoresistance.

An In Vivo Self-Assembled Bispecific Nanoblocker for Enhancing Tumor Immunotherapy

Anti-PD-L1 monoclonal antibody has achieved substantial success in tumor immunotherapy by T-cells activation. However, the excessive accumulation of extracellular matrix components induced by unsatisfactory T-cells infiltration and poor tumor penetration of antibodies make it challenging to realize efficient tumor immunotherapy. Herein, a peptide-based bispecific nanoblocker (BNB) strategy is reported for in situ construction of CXCR4/PD-L1 targeted nanoclusters on the surface of tumor cells that are capable of boosting T-cells infiltration through CXCR4 blockage and enhancing T-cells activation by PD-L1 occupancy, ultimately realizing high-performance tumor immunotherapy. Briefly, the BNB strategy selectively recognizes and bonds CXCR4/PD-L1 with deep tumor penetration, which rapidly self-assembles into nanoclusters on the surface of tumor cells. Compared to the traditional bispecific antibody, BNB exhibits an intriguing metabolic behavior, that is, the elimination half-life (t1/2 ) of BNB in the tumor is 69.3 h which is ≈50 times longer than that in the plasma (1.4 h). The higher tumor accumulation and rapid systemic clearance overcome potential systemic side effects. Moreover, the solid tumor stress generated by excessive extracellular matrix components is substantially reduced to 44%, which promotes T-cells infiltration and activation for immunotherapy efficacy. Finally, these findings substantially strengthen and extend clinical applications of PD-1/PD-L1 immunotherapy.

Nano Proteolysis Targeting Chimeras (PROTACs) with Anti-Hook Effect for Tumor Therapy

Proteolysis targeting chimera (PROTAC) is an emerging pharmacological modality with innovated post-translational protein degradation capabilities. However, off-target induced unintended tissue effects and intrinsic "hook effect" hinder PROTAC biotechnology to be maturely developed. Herein, an intracellular fabricated nano proteolysis targeting chimeras (Nano-PROTACs) modality with a center-spoke degradation network for achieving efficient dose-dependent protein degradation in tumor is reported. The PROTAC precursors are triggered by higher GSH concentrations inside tumor cells, which subsequently in situ self-assemble into Nano-PROTACs through intermolecular hydrogen bond interactions. The fibrous Nano-PROTACs can form effective polynary complexes and E3 ligases degradation network with multi-binding sites, achieving dose-dependent protein degradation with "anti-hook effect". The generality and efficacy of Nano-PROTACs are validated by degrading variable protein of interest (POI) such as epidermal growth factor receptor (EGFR) and androgen receptor (AR) in a wide-range dose-dependent manner with a 95 % degradation rate and long-lasting potency up to 72 h in vitro. Significantly, Nano-PROTACs achieve in vivo dose-dependent protein degradation up to 79 % and tumor growth inhibition in A549 and LNCap xenograft mice models, respectively. Taking advantages of in situ self-assembly strategy, the Nano-PROTACs provide a generalizable platform to promote precise clinical translational application of PROTAC.

[Clinical application of a quantitative method of atlantoaxial reduction angle in basilar invagination]

Objectives: To investigate the clinical application effect of a quantitative method of atlantoaxial reduction angle in basilar invagination. Methods: A retrospective analysis of clinical and radiographic data was conducted of 38 patients with complicated atlantoaxial dislocation and basilar invagination admitted to the Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University from May 2020 to May 2022. There were 5 males and 33 females, aged (53.5±9.9) years (range: 38 to 80 years). All patients underwent C_1-2 interarticular fusion cage implantation+occipital-cervical fixation by pressing rob with the cantilever technique. The atlantoaxial reduction model of previous studies by our team was used to calculate the reduction angles before surgery. Then titanium rods of prebending angle were prepared according to the calculation before the operation. After that quantitative reduction of angle was performed during the operation. The paired t-test was used to compare the difference between the theoretical and actual reset value. Results: The theoretical reduction angle of all patients was (10.62±1.78)° (range: 6.40° to 13.20°), the actual reduction angle was (10.53±1.63)° (range: 6.70° to 13.30°) and there was no statistical difference between them (t=1.688, P=0.100). The theoretical posterior occipitocervical angle after the operation of all patients was (117.37±5.88)° (range: 107.00° to 133.00°), the actual posterior occipitocervical angle after the operation was (118.25±6.77)° (range: 105.40° to 135.80°) and there was no statistical difference between them (t=-0.737, P=0.466). The postoperative follow-up time of the patients was more than 6 months and the symptoms of all patients were relieved. All patients had satisfactory fusion between small joints without incision infection, internal fixation fracture, displacement, atlantoaxial redislocation, and other long-term complications. Conclusion: The quantitative method of atlantoaxial reduction angle in basilar invagination can calculate the theoretical reduction angle of the clivus axis angle and guide the preparation of the pre-bending titanium rod before surgery, so as to realize the quantification of the atlantoaxial reduction angle.

A bispecific glycopeptide spatiotemporally regulates tumor microenvironment for inhibiting bladder cancer recurrence

Up to 75% of bladder cancer patients suffer from recurrence due to postoperative tumor implantation. However, clinically used Bacillus Calmette-Guerin (BCG) treatment failed to inhibit the recurrence. Here, we report a bispecific glycopeptide (bsGP) that simultaneously targets CD206 on tumor-associated macrophages (TAMs) and CXCR4 on tumor cells. bsGP repolarizes protumoral M2-like TAMs to antitumor M1-like that mediated cytotoxicity and T cell recruitment. Meanwhile, bsGP is cleaved by the MMP-2 enzyme to form nanostructure for the long-term inhibition of CXCR4 downstream signaling, resulting in reduced tumor metastasis and promoted T cell infiltration. In orthotopic bladder tumor models, bsGP reduced the postoperative recurrence rate to 22%. In parallel, the recurrence rates of 89 and 78% were treated by doxycycline and BCG used in clinic, respectively. Mechanistic studies reveal that bsGP reduces the matrix microenvironment barrier, increasing the spatially redirected CD8⁺ T cells to tumor cells. We envision that bis-targeting CD206 and CXCR4 may pave the way to inhibit tumor metastasis and recurrence.

[Research progress in the association of peri-implant diseases and metabolic syndrome]

Peri-implant disease, an important group of diseases that cause implant failure, are associated with metabolic abnormality. Metabolic syndrome (MetS) is a common metabolic disorder comprising abdominal obesity, hyperglycemia, systemic hypertension and atherogenic dyslipidemia. Previous studies had reported that MetS and its diversified clinical manifestations might be associated with peri-implant diseases, but the relationship and underlying mechanisms were unclear. This review aims to explore the relationship between MetS and peri-implant disease, in order to provide beneficial reference for the prevention and treatment of peri-implant disease in patients with MetS.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

[Feasibility and effectiveness of application of internet-based HIV testing in men who have sex with men]

Objective: To evaluate the feasibility and effectiveness of the application of internet-based HIV testing in men who have sex with men (MSM) in practical application and provide evidence for its application in the future. Methods: MSM who visited the internet-based intervention platform for at least one time from June to December 2020 were selected for the study. The information about platform visit, the number of self-test kits provided, the basic characteristics of the MSM and their satisfactory level were collected. And multivariable logistic regression analyses were conducted to identify the potential factors associated with the reporting of self-test results. Results: By the end of December 31^th, 2020, a total of 132 267 platform visits had been recorded, and 3 511 HIV self-test kits had been provided upon the MSM's requests, and 3 237 MSM (92.2%) reported self-test results. The HIV positive rate was 2.4% (69/2 855) and the confirmation rate of positive HIV test results was 86.7% (52/60). The MSM who asked for self-test kits online were mainly aged ≤30 years, had education level of college or above, and found their sexual partners through internet or dating software. Multivariable logistic regression analyses showed that repeat of online HIV self-test kits application (OR=3.50,95%CI:2.10-5.83), guarantee deposit of 50 yuan at application (OR=2.55,95%CI:1.33-4.89), monthly economic income 1-3 000 yuan (OR=1.54,95%CI:1.05-2.28) or no income (OR=1.71,95%CI:1.20-2.42) and online sexual partners finding (OR=1.49,95%CI:1.13-1.95) were associated with higher reporting rate of self-test results. The satisfactory rate the MSM to the service of platform was 99.5% (217/218). Conclusions: The study confirmed the feasibility and effectiveness of internet-based intervention for HIV tests in MSM, which could promote the self-test of HIV in MSM and facilitate the early detection of HIV infection through social media platforms and multi-channel promotion.

[Mediation effect of inflammatory biomarkers on the association between blood lead levels and blood pressure changes in Chinese adults]

Objective: To investigate the role of inflammatory biomarkers in the relationship between blood lead levels and blood pressure changes. Methods: A total of 9 910 people aged 18-79 years who participated in the China National Human Biomonitoring in 2017-2018 were included in this study. A self-made questionnaire was used to collect demographic characteristics, lifestyle and other information, and the data including height, weight and blood pressure were determined through physical examination. Blood and urinary samples were collected for the detection of blood lead and cadmium levels, urinary arsenic levels, white blood cells, neutrophils, lymphocytes, and hypersensitive C-reactive protein (hs-CRP). Weighted linear regression models were used to evaluate the associations between blood lead, inflammatory biomarkers and blood pressure. Mediation analysis was performed to investigate the role of inflammation in the relationship between blood lead levels and blood pressure changes. Results: The median (Q₁, Q₃) age of all participants was 45.4 (33.8, 58.4)years, including 4 984 males accounting for 50.3%. Multivariate logistic regression model analysis showed that after adjusting for age, gender, residence area, BMI, education level, smoking and drinking status, family history of hypertension, consumption frequency of rice, vegetables, and red meat, fasting blood glucose, total cholesterol, triglycerides, blood cadmium and urinary arsenic levels, there was a positive association between blood lead levels, inflammatory biomarkers and blood pressure (P<0.05). Each 2.71 μg/L (log-transformed) increase of the lead was associated with a 2.05 (95%CI: 0.58, 3.53) mmHg elevation in systolic blood pressure (SBP), 2.24 (95%CI: 1.34, 3.14) mmHg elevation in diastolic blood pressure (DBP), 0.25 (95%CI: 0.05, 0.46) mg/L elevation in hs-CRP, 0.16 (95%CI: 0.03, 0.29)×10⁹/L elevation in white blood cells, and 0.11 (95%CI: 0.02, 0.21)×10⁹/L elevation in lymphocytes, respectively. Mediation analysis showed that the levels of hs-CRP significantly mediated the association of blood lead with SBP, with a proportion about 3.88% (95%CI: 0.45%, 7.32%). The analysis also found that the levels of hs-CRP and neutrophils significantly mediated the association of blood lead with SBP, with a proportion about 4.10% (95%CI: 1.11%, 7.10%) and 2.42% (95%CI: 0.07%, 4.76%), respectively. Conclusion: This study suggests that inflammatory biomarkers could significantly mediate the association of blood lead levels and blood pressure changes.

[Clinical characteristics of 16 neonates infected with SARS-CoV-2 during Omicron variant outbreak]

Objective: To analyze the clinical characteristics of the neonates infected with SARS-CoV-2 during the Omicron outbreak in Shanghai 2022. Methods: In this retrospective case series study, all the 16 neonates with SARS-CoV-2 Omicron infection who were admitted to the neonatal unit in Shanghai Public Health Clinical Center from March 1^st to May 31^st, 2022 were enrolled. Their epidemiological history, clinical manifestations, nucleic acid cycle threshold (Ct) value and outcomes were analyzed. Based on maternal vaccination, they were divided into vaccinated group and unvaccinated group. Rank sum test and Chi-square test were used for the comparison between the groups. Results: Among the 16 neonates, 10 were male, and 6 were female. All the infants were full-term. The infection was confirmed at the age of 12.5 (8.0, 20.5) days. All the neonates had a history of exposure to infected family members, and thus horizontal transmission was the primary mode. Four infants were asymptomatic, 12 were symptomatic, and there were no severe or critical cases. The most common clinical manifestation was fever (11 cases), with the highest temperature of 38.1 (37.9, 38.3) ℃ and a course of 1-5 days. Other clinical manifestations included nasal obstruction (3 cases), runny nose (2 cases), cough (2 cases), poor feeding (2 cases), vomiting (1 case), and mild tachypnea (1 case). The complete blood counts of all neonates were within the normal range, and the C-reactive protein increased slightly in 1 infant. Chest imaging was performed in 2 infants, showing mild focal exudative changes. Nucleic acid turned negative (Ct value ≥35) within 7-15 days after diagnosis. All neonates fully recovered after supportive treatment, and the length of hospitalization was 13 (10, 14) days. In the telephone follow-up 2 weeks after discharge for all 16 cases, no infant showed reoccurrence of clinical manifestations or nucleic acid reactivation. Maternal vaccination was not significantly correlated with symptomatic infection or the persistence of positive nucleic acid result in neonates (all P>0.05). Conclusions: Horizontal transmission is the primary mode for neonatal SARS-CoV-2 Omicron infection. Neonatal infections are usually mild or asymptomatic, with good short-term outcomes. And their clinical manifestations and laboratory examinations are nonspecific.

[Management and short-term outcomes of neonates born to mothers infected with SARS-CoV-2 Omicron variant]

Objective: To summarize the management and short-term outcomes of neonates delivered by mothers infected with SARS-CoV-2 Omicron variant. Methods: A retrospective study was performed on 158 neonates born to mothers infected with SARS-CoV-2 Omicron variant admitted to the isolation ward of Children's Hospital of Fudan University from March 15^th, 2022 to May 30^th, 2022. The postnatal infection control measures for these neonates, and their clinical characteristics and short-term outcomes were analyzed. They were divided into maternal symptomatic group and maternal asymptomatic group according to whether their mothers had SARS-CoV-2 symptoms. The clinical outcomes were compared between the 2 groups using Rank sum test and Chi-square test. Results: All neonates were under strict infection control measures at birth and after birth. Of the 158 neonates, 75 (47.5%) were male. The gestational age was (38⁺³±1⁺³) weeks and the birth weight was (3 201±463)g. Of the neonates included, ten were preterm (6.3%) and the minimum gestational age was 30⁺¹ weeks. Six neonates (3.8%) had respiratory difficulty and 4 of them were premature and required mechanical ventilation. All 158 neonates were tested negative for SARS-COV-2 nucleic acid by daily nasal swabs for the first 7 days. A total of 156 mothers (2 cases of twin pregnancy) infected with SARS-CoV-2 Omicron variant, the time from confirmed SARS-CoV-2 infection to delivery was 7 (3, 12) days. Among them, 88 cases (56.4%) showed clinical symptoms, but none needed intensive care treatment. The peripheral white blood cell count of the neonates in maternal symptomatic group was significantly higher than that in maternal symptomatic group (23.0 (18.7, 28.0) × 10⁹ vs. 19.6 (15.4, 36.6) × 10⁹/L, Z=2.44, P<0.05). Conclusions: Neonates of mothers infected with SARS-CoV-2 Omicron variant during third trimester have benign short-term outcomes, without intrauterine infection through vertical transmission. Strict infection control measures at birth and after birth can effectively protect these neonates from SARS-CoV-2 infection.

Programmable design and self assembly of peptide conjugated AIEgens for biomedical applications

Aggregation-induced emission luminogens (AIEgens) possess enhanced fluorescence in highly aggregated states, thus enabling AIEgens as a promising module for highly emissive fluorescence biomaterials. So far, AIEgens-based nanomaterials and their hybrids have been reported for biomedical applications. Benefiting from the intrinsic biocompatibility and biofunction-editing properties of peptides, peptide-AIEgens hybrid biomaterials reveal unlimited possibilities including target capacity, specificity, stimuli-responsiveness, self-assembly, controllable structural transformation, etc.. In the last two decades, peptide-AIEgens hybrid nanomaterials with a unique design concept in aggregated states have achieved various biomedical applications such as biosensing, bioimaging, imaging-guided surgery, drug delivery and therapy. More recently, programmable design of peptide-AIEgens for in situ self-assembly provides a unique strategy for constructing intelligent entities with defined biological functions. In this review, we summarize the basic design principle of programmable peptide-AIEgens, structure-effect relationship and their unusual biomedical effects. Finally, an outlook and perspective toward future challenges and developments of peptide-AIEgens nanomaterials are concluded.

A Lysosome-Targeting Self-Condensation Prodrug-Nanoplatform System for Addressing Drug Resistance of Cancer

Lysosome-targeting self-assembling prodrugs had emerged as an attractive approach to overcome the acquisition of resistance to chemotherapeutics by inhibiting lysosomal sequestration. Taking advantage of lysosomal acidification induced intracellular hydrolytic condensation, we developed a lysosomal-targeting self-condensation prodrug-nanoplatform (LTSPN) system for overcoming lysosome-mediated drug resistance. Briefly, the designed hydroxycamptothecine (HCPT)-silane conjugates self-assembled into silane-based nanoparticles, which were taken up into lysosomes by tumor cells. Subsequently, the integrity of the lysosomal membrane was destructed because of the acid-triggered release of alcohol, wherein the nanoparticles self-condensed into silicon particles outside the lysosome through intracellular hydrolytic condensation. Significantly, the LTSPN system reduced the half-maximal inhibitory concentration (IC₅₀) of HCPT by approximately 4 times. Furthermore, the LTSPN system realized improved control of large established tumors and reduced regrowth of residual tumors in several drug-resistant tumor models. Our findings suggested that target destructing the integrity of the lysosomal membrane may improve the therapeutic effects of chemotherapeutics, providing a potent treatment strategy for malignancies.

In Situ Constructed Nano-Drug Depots through Intracellular Hydrolytic Condensation for Chemotherapy of Bladder Cancer

Intravesical administration of first-line drugs has shown failure in the treatment of bladder cancer owing to the poor tumor retention time of chemotherapeutics. Herein, we report an intracellular hydrolytic condensation (IHC) system to construct long-term retentive nano-drug depots in situ, wherein sustained drug release results in highly efficient suppression of bladder cancer. Briefly, the designed doxorubicin (Dox)-silane conjugates self-assemble into silane-based prodrug nanoparticles, which condense into silicon particle-based nano-drug depots inside tumor cells. Significantly, we demonstrate that the IHC system possesses highly potent antitumor efficacy, which leads to the regression and eradication of large established tumors and simultaneously extends the overall survival of air pouch bladder cancer mice compared with that of mice treated with Dox. The concept of intracellular hydrolytic condensation can be extended via conjugating other chemotherapeutic drugs, which may facilitate rational design of novel nanomedicines for augmentation of chemotherapy.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Targeted in situ self-assembly augments peptide drug conjugate cell-entry efficiency

Peptide drug conjugate (PDC) has emerged as one of the new generations of targeted therapeutics for cancer, which owns the advantages of improved drug targetability and reduced adverse effects compared with traditional chemotherapy. However, the poor permeability of PDC drugs regarding tumor cells is an urgent problem to be solved. Herein, we design a PDC drug molecule, which is composed of three modules: targeting motif (RGD target), assembly motif (GNNNQNY) and cytotoxic payload (CPT molecule). This PDC in situ forms nanoclusters upon binding cellular receptor, resulting in improved PDC cell-entry efficiency and treatment efficacy. In addition, the PDC shows increased therapeutic efficacy and raises the maximum tolerance dose of the drug in breast and bladder xenografted mice models. This strategy leverages the assembly principle to promote penetration of peptide molecules into cells and increase intracellular drug bioavailability, which is of great significance for the development of PDC drugs in the future.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

[Association of cadmium internal exposure with chronic kidney disease in Chinese adults]

Objective: To analyze the association of the cadmium internal exposure with chronic kidney disease (CKD) in Chinese adults aged 18 and older. Methods: A total of 9 821 adults aged 18-79 from the China National Human Biomonitoring (CNHBM) from 2017 to 2018 were included. Blood and urine cadmium exposure levels were measured by inductively coupled plasma mass spectrometry (ICP-MS), and urine cadmium levels were adjusted with urine creatinine; CKD were defined by estimated glomerular filtration (eGFR) using the chronic kidney disease epidemiology collaboration (CKD-EPI). Weights were considered due to complex sampling process for in statistical analysis. Logistic regression is used to analyze the association of blood cadmium, urine cadmium, and urine cadmium adjusted with creatinine exposure levels with CKD, and restricted cube spline (RCS) was used to assess the exposure-response curve of blood cadmium, urine cadmium and urine cadmium adjusted with creatinine with CKD. Results: The weighted age was 44.75 and males accounted for 61.1%. The prevalence rate of CKD was 12.7%. The geometric mean values of blood cadmium, urine cadmium, and urine cadmium adjusted with creatinine were 0.96 μg/L, 0.61 μg/L, and 0.58 μg/g. After adjusting for confounding factors, the weighted logistic regression showed that the lowest quintile (Q1) was compared with the odds ratio (OR) of the highest quintile (Q5) of blood cadmium, urine cadmium, and urine cadmium adjusted with creatinine and the 95% confidence interval (CI) was 1.80 (1.02-3.20), 1.77 (0.94-3.31) and 1.94 (1.11-3.37) respectively. In the restricted cubic spline regression model, non-linear association of blood cadmium, urine cadmium, and urine cadmium adjusted with creatinine with CKD were observed after adjusting for related confounding factors (P<0.001, 0.018, 0.031 respectively). The risk of CKD increased with the increment of cadmium exposure without risk threshold, and the exposure response curve was steeper at low cadmium exposure. Conclusions: Among Chinese adults aged 18 and older, cadmium exposure is positively associated with the risk of chronic kidney disease.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[The distribution and variance of neonatal pulse oxygen saturation at different altitudes]

Objective: To analyze the distribution and variance of neonatal pulse oxygen saturation (SpO₂) at different altitudes in China, and provide a new evidence for the screening of NCHD at high altitudes. Methods: Based on the database of National Screening Project of NCHD, the distribution of SpO₂ values was described in 26 766 newborns at altitudes of 0-100 m, 600-700 m, 900-1 100 m, 1 400-1 600 m, 1 900-2 100 m, and 2 200-2 500 m. One-way analysis of variance was used to analyze the differences among SpO₂ values in newborns at different altitudes. Results: The average SpO₂ values of right hand in newborns at altitudes of 0-100 m, 600-700 m, 900-1 100 m, 1 400-1 600 m, 1 900-2 100 m and 2 200-2 500 m were 97.7%±1.4%, 97.1%±1.1%, 96.1%±1.3%, 96.0%±1.7%, 95.9%±1.7% and 95.5%±2.4%, respectively. And corresponding average SpO₂ values of either foot were 97.7%±1.4%, 96.9%±1.1%, 96.3%±1.4%, 96.0%±1.7%, 95.6%±1.8% and 95.2%±2.7%, respectively. There were statistically significant differences in the average SpO₂ values of newborns at different altitudes (right hand: F=1 248.35, P<0.001; either foot: F=1 280.45, P<0.001). The SpO₂ of newborns tended to be lower with the increase of altitudes (P-trend<0.001). Conclusion: SpO₂ values in newborns were negatively associated with the altitudes, which indicated that the cut-off value of screening for NCHD at sea level might not be applicable to newborns at higher altitudes. Thus, it is worthwhile to conducted studies on the normal values of SpO₂ and the cut-off value of screening for NCHD in newborns at high altitudes.

[Geometric model of reduction in basilar invagination with atlantoaxial dislocation and its clinical application]

Objectives: To establish a geometric model of the atlantoaxial dislocation and basilar invagination reduction,and examine its value for clinical application. Methods: A retrospective analysis of 35 patients with atlantoaxial dislocation and basilar invagination admitted to the Department of Neurosurgery,First Affiliated Hospital of Chongqing Medical University from May 2018 to May 2020 was conducted.There were 5 males and 30 females,aged (48±15) years(range: 19 to 69 years). The geometric model of the atlantoaxial reduction was established based on the mid-sagittal section of the cervical spine. The relevant data were calculated according to the geometric model before operation,and the fusion cage of the corresponding height was placed into C_1-2 facet joint of patient for quantitative reduction. The theoretical reset value, actual reset value, postoperative symptoms and complications were collected. The paired t-test was used to compare the difference between theoretical and actual reset value to verify the reliability of the geometric model. Results: The theoretical vertical reduction distance of all patients was (5.79±2.96) mm(range:1.52 to 10.96 mm),and the actual vertical reduction distance was (7.43±2.96)mm(range: 1.40 to 12.77 mm),and there was no statistical difference between them(t=-1.96,P=0.069).The theoretical reduction angle was (10.80±2.24)°(range: 7.09 to 14.86°), the actual reduction angle was (10.64±7.00)°(range: 3.50 to 20.50°),and there was no statistical difference between them (t=0.09, P=0.933). At 6 months follow-up, 35 patients achieved satisfactory atlanto-axial joint fusion, and the symptoms were relieved. No internal fixation system displacement, fracture, wound infection and other complications occurred. Conclusion: This geometric model can estimate the vertical reduction distance and the reduction angle of the axial before operation,and provide a reference for the height of the fusion cage so as to avoid under or over-reduction.

Precise label-free leukocyte subpopulation separation using hybrid acoustic-optical chip

Leukocyte subpopulations contain crucial physiological information; hence, precise and specific leukocyte separation is very important for leukemia diagnosis and analysis. However, conventional centrifugation and immunofluorescence-based separation methods are inaccurate and inconvenient due to the overlapping cell size and density or complex marking processes. Herein, we report a new label-free technology for precise leukocyte subpopulation separation by synergy of acoustic and optical technologies. Standing surface acoustic wave (SSAW) solved the problem of gentle and precise focusing of cells in optical systems. In addition, SSAW was used for the separation of granulocytes, which have evident size distinction from other components. In case of lymphocytes and monocytes, which have overlap in size/density, optical force could distinguish them accurately based on the RI difference, with the convenience of acoustic pre-focusing. In this experiment, separation of three types of leukocyte subtypes with considerable throughput and purity was conducted, through which we obtained 99% pure lymphocytes, 98% pure monocytes, and 95% pure granulocytes. Experimental results prove that the device has robust ability in separating leukocyte phenotypes and have the advantages of being non-invasive, label-free and precise. In the future, this convenient hybrid method will be a potential powerful tool for auxiliary clinical diagnosis and analysis.

[The study of the rational use of antibiotics after nasal surgery]

Objective:To study whether the antibiotics should be used in the patients with or without chronic nasal sinusitis after the nasal surgery,and how to rationally use it.Method：Study design:prospective stratified randomized controlled study.Patients with sinusitis were divided into three groups.A group was without antibiotics,B group was with standard antibiotics using ,and C group was with prolonged antibiotics using.Patients without sinusitis were divided into D group without antibiotics,E group with standard antibiotics using,and F group with prolonged antibiotics using. Observe the postoperative infection rate in each group and compare them.Result：The infection rates were 3.53%,2.67%,0.00% in A,B and C group, and there was no significant differences between three groups. The infection rates were 1.22%,0.00%,1.39% in D,E and F group,and there was no significant differences between them.Conclusion： There was no influence in patients with or without using antibiotics,standard or prolonged using antibiotics after nasal surgery. Recommend not to use antibiotics after nasal surgery,and appropriately use antibioctics within 48 hours.Prolonged using is not recommended.

[The correlation between normal or abnormal vestibule function and prognosis of the low frequency sudden deafness]

Objective:To study the correlation between prognosis and status of the vestibule functions with the patients of the low frequency sudden deafness (SD). Method:Eighty-eight patients with low frequency SD were enrolled in this study, the cervical vestibular evoked myogenic potential (cVEMP), the ocular VEMP (oVEMP) and caloric test were evaluated. Based upon the results of the test, patients were divided into 4 groups. A group has no abnormal test results, B group has one abnormal test results, C group has two abnormal test results,and D group has three abnormal test results. Calculating and comparing the effective rate and uneffective rate were conducted in every group after treatment. Result:In A group, the effective rate is 27.27%, the uneffective rate is 2.27%. In B group, the effective rate is 36.36%, the uneffective rate is 4.55%.In C group, the effective rate is 9.09%, the uneffective rate is 6.82%. In D group, the effective rate is 0%, the uneffective rate is 13.64%. The difference between effective and uneffective rate was significant in group A, B, and D, while, there was no significant difference in group C. Conclusion:The prognosis of low frenquency SD patients without abnormal test results or only with one abnormal test results is good. While, the prognosis of patients with three abnormal test is bad. The prognosis of patients with two abnormal test is not sure. The vestibule functions test can be used to determine the prognosis of low frequency SD in clinical treatment.

[Autosomal dominant hearing loss resulting from mutation in the GJB2 gene:nonsyndromic presentation in a Chinese family]

Objective:To investigate the genotype, phenotype and genetic features. The mutations in GJB2, GJB3, GJB6, SLC26A4 genes, 12SrRNA and tRNASer(UCN) were tested in a Chinese family with autosomal dominant nonsyndromic hearing loss. Method:Blood samples and clinical data of the proband and her partial family members were collected. DNA was extracted from the blood samples. The GJB2, GJB3, GJB6, SLC26A4 genes, 12SrRNA and tRNASer(UCN) mutations were analyzed by polymerase chain reaction(PCR) and direct sequencing. Result:Heterozygous mutation of GJB2 R75Q was identified in the proband and her mother. No mutation of other testing genes was detected. Conclusion:The R75Q mutation of the GJB2 gene cause autosomal dominant nonsyndromic deafness in the proband and her mother. Children can inherit the R75Q mutation from their parents, so the results of gene testing will be helpful for further guidance of procreation.

[Tympanum meningioma: one case report]

Clinical presatation: right ear tinnitus, hearing loss, headache for 1 year with intermittent vertigo for 9 months. Specialized examination: right ear tympanum hyperemia and edema, right ear severe conduction deafness, left ear mild hearing loss. The average threshold: right ear 65 dB, the left ear 35 dB. Imaging examination: CT showed the soft tissue density mass in the right ear tympanum, part of the ear bone obscurity, superior wall of the tympanic cavity attenuation, tympanic sinus entry is not expanding. Imaging diagnosis: chronic otitis media with cholesteatoma formation. Postoperative diagnosis: meningioma.

Turning carbon nanotubes from exceptional heat conductors into insulators

Thermal conductivity (kappa) of isolated carbon nanotubes (CNTs) is higher than the kappa of diamond; however, in this Letter we show that the kappa of a packed bed of three-dimensional random networks of single and multiwall CNTs is smaller than that of thermally insulating amorphous polymers. The thermoelectric power (Sigma) of the random network of CNTs was also measured. The Sigma of a single wall nanotube network is very similar to that of isolated nanotubes and, in contrast with kappa, Sigma shows a strong dependence on the tube diameter.

Resonant Raman scattering of the smallest single-walled carbon nanotubes

We report optical properties of the smallest single-walled carbon nanotubes (SWNTs) with a diameter of only 3 A. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of an AlPO-11 (AEL) single crystal. Polarized and resonant Raman scattering unambiguously revealed that these 0.3 nm SWNTs are of (2,2) armchair symmetry. Interestingly, the (2,2) armchair tube has two metastable ground states corresponding to two slightly different lattice constants in the axial direction: one state is metallic and the other is semiconducting.

Competing drug-drug interactions among multidrug antiretroviral regimens used in the treatment of HIV- infected subjects: ACTG 884

OBJECTIVE

To evaluate the steady state concentrations of saquinavir, ritonavir, nelfinavir, delavirdine, and adefovir in six different three- and four-drug combination regimens.

DESIGN

Randomized, partially double-blinded, multicenter study in a population of indinavir-experienced subjects with virologic failure. The first seven subjects enrolled in each of the six treatment arms from 10 participating sites were entered into this pharmacokinetic evaluation.

SETTING

Multicenter study of the AIDS Clinical Trials Group (ACTG).

PATIENTS

HIV-infected subjects.

INTERVENTIONS

A 12-hour pharmacokinetic study was conducted after 2 weeks of drug administration.

MAIN OUTCOME MEASURES

Area under the concentration-time curve with statistical comparisons to evaluate the effect of the second protease inhibitor and the effect of the non-protease inhibitors.

RESULTS

There was no difference in saquinavir concentrations according to whether the second protease inhibitor was ritonavir or nelfinavir. Saquinavir concentrations in the groups receiving the combination of delavirdine plus adefovir dipivoxil were reduced by approximately 50% compared with those receiving delavirdine. Delavirdine concentrations were reduced by approximately 50%, in the delavirdine plus adefovir dipivoxil arms compared with the delavirdine arms.

CONCLUSIONS

Saquinavir concentrations were significantly lower in the arms containing the combination of delavirdine and adefovir dipivoxil compared with the arms containing delavirdine. Delavirdine concentrations were significantly lower when coadministered with adefovir dipivoxil. These drug-drug interactions were not expected, the mechanism(s) is (are) not clear, and additional studies are warranted. This study illustrates the need to understand more fully the pharmacokinetic characteristics of complex combination antiretroviral regimens prior to use in patient management.

Randomized study of saquinavir with ritonavir or nelfinavir together with delavirdine, adefovir, or both in human immunodeficiency virus-infected adults with virologic failure on indinavir: AIDS Clinical Trials Group Study 359

This study compared antiretroviral activity among 6 "salvage" therapy regimens. The study was a prospective, randomized, 2x3 factorial, multicenter study of the AIDS Clinical Trials Group. The study enrolled 277 human immunodeficiency virus (HIV)-infected patients naive to nonnucleoside analogues who had taken indinavir >6 months. The patients had 2000-200,000 HIV RNA copies/mL. Patients received saquinavir with ritonavir or nelfinavir together with delavirdine and/or adefovir and were followed for safety and antiretroviral response between baseline and week 16. At week 16, 30% (77/254) of patients had </=500 HIV RNA copies/mL. Virologic response did not differ significantly between pooled ritonavir and nelfinavir groups (28% vs. 33%; P=.50) or between pooled delavirdine and delavirdine/adefovir groups (40% vs. 33%; P=.42). Pooled delavirdine groups had a greater virologic response rate than did adefovir groups (40% vs. 18%; P=.002). Overall, one-third of patients who experienced virologic failure on an indinavir-containing regimen suppressed virus load levels while they were taking a new salvage regimen.

The abnormality of glucose transporter in the erythrocyte membrane of Chinese type 2 diabetic patients

Type 2 diabetes mellitus is characterized by impaired glucose uptake. With a photometric method of recording the erythrocyte suspension absorption during the course of glucose transport across the membranes, we observed that the initial rate of glucose zero-trans entry was decreased significantly in 30 Chinese type 2 diabetic patients as compared to 25 healthy controls. The rate of glucose infinite-cis efflux exhibited no difference between the patients and controls. The measurement of temperature dependence of glucose transport showed that the activation energy for glucose entry was increased in diabetic patients. The inhibitory constant of glucose entry by cytochalasin B (CB) in patients was similar to that of the controls. However, we found that the inhibitory constant was increased significantly in the patient erythrocytes after phloretin treatment. After the erythrocytes were made into stripped white ghosts, the fluorescence quenching experiment was performed. Glucose, CB and phloretin can quench the fluorescence of tryptophan residues in the glucose transporter 1, GLUT1. The abnormality of fluorescence quenching in the erythrocyte membranes of patients was observed. The transfer tendency of tryptophan residues from the hydrophilic environment to the hydrophobic environment was decreased in patient ghosts as binding with glucose, and the opposite tendency appeared as CB and phloretin instead of glucose. We conclude that the decreased in glucose entry in the erythrocyte membranes of diabetic patients was due to the GLUT1 change in structure - mostly the outer domain of the glucose transporter.

Preparation and immunogenicity of serogroup B meningococcal OS-OMPC conjugates

The objective of the present study is to purify oligosaccharides (OSs) from serogroup B meningococci (3407 or 542852) with common lipooligosaccharide (LOS) immunotypes prevalent in China and to successfully conjugate them to their outer membrane protein complexes (OMPCs). Conjugates possessing broad cross-reactivity with different serogroup B meningococci were obtained. Both LOSs from the above two strains were purified on a Sephadex G75 column and hydrolyzed with acetic acid, and then the pure OSs were obtained by using a Sephadex G50 chromatographic column. The pure OSs were conjugated to corresponding OMPCs by carbodiimide mediated condensation. Mice were immunized with the OS-OMPC conjugates to produce antibodies. Immunogenicities of the conjugates were tested by ELISA, bactericidal test and Western-blotting. The titers of antibodies against OS and LOS elicited by the two OS-OMPC conjugates increased respectively by 2.5 and 2 to 10 times as compared with those of antibodies against unconjugated OS and LOS. The sera elicited by the conjugates possessed a stronger bactericidal activity to the strains (3407, 542852, 29021) with the same LOS immunotype than to the strain with different LOS immunotype (86155). The results determined by ELISA indicated that the sera against the conjugates showed strong response to the strains with the same or different LOS immunotypes. It was confirmed by western-blotting analysis that the sera elicited by the two conjugates reacted with 42, 39 and 26 kDa proteins from the OMPC. Among the reactive bands, the 42 kDa proteins were class 1 OMPs. The two serogroup B meningococcal OMPCs were strong immunogens and good carriers coupling with OSs as well. The immunogenicity of the conjugated OS was increased and the OS-OMPC conjugates of the serogroup B meningococci showed a broad antigenic response to the strains tested.

Group sequential analyses for the mean function of a repeated measure process

In many clinical trials, treatment efficacy is based upon response to a biological marker that is measured repeatedly during the course of follow-up. However, in some of these trials it is not clear, a priori, how treatment effects on the marker may manifest themselves or what kinds of effects are clinically meaningful and/or acceptable. It is, therefore, desirable to allow flexibility in design and monitoring process by not prespecifying a stopping rule or even the parameter on which inferences will be based. Using the more general results in Hu and Lagakos, this paper extends the idea of the repeated confidence intervals for a parameter (Jennison and Turnbull) to repeated confidence bands for the mean function of a repeated measure process. We illustrate the approach and some considerations in its application with the results of a recent AIDS clinical trial.

[Effects of doxepin on isolated basilar and saphenous artery rings of rabbits]

AIM

To study the effects of doxepin (Dox) on cerebral artery.

METHODS

The effects of Dox were observed using the isolated basilar and saphenous artery rings of rabbits.

RESULTS

Dox inhibited the constriction of the basilar and saphenous artery rings evoked by KCl with IC50 5.75 mumol.L-1 (95% confidence limits were 2.3-14 mumol.L-1, n = 8) and 34.6 mumol.L-1 (95% confidence limits were 3.8-316 mumol.L-1, n = 8), respectively. Dox also inhibited the constriction of the basilar and saphenous artery rings of the rabbits stimulated by 5-hydroxytryptamine (5-HT), IC50 were 6.3 mumol.L-1 (95% confidence limits were 1.7-23.3 mumol.L-1, n = 7) and 8.0 mumol.L-1 (95% confidence limits were 6.3-10.3 mumol.L-1, n = 6), respectively. In both samples (basilar and saphenous artery rings) CaCl2 evoked, the pD2 of Dox was 5.28 +/- 0.40 and 4.76 +/- 0.14, respectively (n = 6, P < 0.01). Dox 5.8 mumol.L-1 inhibited the constriction of the saphenous artery evoked by norepinephrine (NE) in Ca(2+)-free medium. Dox 30 mumol.L-1 inhibited the constriction of the saphenous artery evoked both by NE and by readmission of CaCl2 (1.25 mmol.L-1).

CONCLUSION

As compared with its effect on the saphenous artery, Dox selectively inhibited the basilar artery.

The distal cytoplasmic domain of the erythropoietin receptor induces granulocytic differentiation in 32D cells

The role of hematopoietic growth factors in lineage commitment and differentiation is unclear. We present evidence that heterologous expression of an erythroid specific receptor allows granulocytic differentiation of a myeloid cell line. We have previously characterized a truncation mutant of the erythropoietin receptor (EpoR), which is associated with familial erythrocytosis (Blood 89:4628, 1997). This truncated EpoR lacks the distal 70 amino acids of the cytoplasmic domain. To study the functional role of this distal receptor domain, 32D cells, a murine interleukin-3 (IL-3)-dependent myeloid line, were transfected with the wild-type EpoR (32D/EpoR WT) or the truncated EpoR (32D/EpoR FE). 32D cells expressing either the full-length or truncated EpoR display equivalent proliferative rates in saturating concentrations of Epo. There is a dramatic difference in maturational phenotype between the two cell lines, however. The 32D/EpoR FE cells and mock transfected 32D cells have an immature, monoblastic morphology and do not express the primary granule protein myeloperoxidase. The 32D/EpoR WT cells, on the other hand, demonstrate granulocytic differentiation with profuse granulation, mature, clumped chromatin, and myeloperoxidase expression. There is no evidence of erythroid differentiation in 32D cells transfected with either the full-length or truncated EpoR. Treatment of the cells with the specific Jak2 inhibitor tyrphostin AG 490 inhibits myeloid differentiation driven by the distal EpoR. We conclude that: (1) the distal cytoplasmic domain of the EpoR is able to induce a specific myeloid differentiation signal distinct from mitogenic signaling, and (2) these data extend to myelopoiesis the growing body of evidence that the cellular milieu, not the specific cytokine receptor, determines the specificity of differentiation after cytokine receptor activation.

Functional characterization of a kindling-like model of ethanol withdrawal in cortical cultured neurons after chronic intermittent ethanol exposure

Chronic ethanol exposure has been reported to alter NMDA and GABA(A) receptor function and gene expression in brain regions of animals and mammalian cultured cortical neurons. In the present study, we investigated the effects of another model of chronic, but intermittent, ethanol treatment (CIE) on GABA(A) and NMDA receptor systems in cortical neurons. CIE (50 mM ethanol, 12 h exposure/12 h withdrawal, 5 cycles) exposure produced increased [3H]MK-801 binding and diazepam insensitive binding sites as measured by [3H]Ro15-4513 binding to cortical cultured neuronal membranes, at 0 h following the last treatment cycle relative to control neurons. The NMDA mediated increase in intracellular calcium [Ca2+]i was also increased following similar CIE treatment. CIE treatment also increased the ability of pentylenetetrazol (PTZ) to inhibit GABA mediated 36Cl- influx relative to control neurons. These effects were not reversible following 1 week ethanol withdrawal, implying enhanced sensitivity of PTZ to inhibit GABA(A) receptor mediated inhibition, and an increased NMDA receptor function in CIE treated cortical neurons. These alterations are consistent with the behavioral studies in animals, and suggest that both GABA(A) and NMDA receptors play an important role in ethanol withdrawal following either chronic or CIE exposure. Furthermore, this provides a feasible in vitro model for further biochemical and molecular studies of the mechanism underlying the CIE induced kindling-like phenomenon observed in humans.

[Changes of synaptic transmission efficiency in the MF-CA3 and PP-CA3 pathways of rat hippocampus during discrimination learning]

Electrophysiological and behavioral studies were performed in rat to investigate the changes of synaptic efficacy of the two inputs of hippocampal CA3 area [Mossy Fiber (MF) -CA3 and Perforant Path (PP) -CA3] during discrimination learning. The results showed that: (1) Amplitude of the population spike (PS) of both from MF-CA3 and PP-CA3 increased simultaneously with the establishment of conditioned response (CR) and both reached their maxima before CR reached the criterion of acquisition. (2) During natural extinction of CR, the amplitude of PS of both inputs decreased also simultaneously to their per-training level. These results indicated that the learning-dependent long-term potentiation (LTP) in both MF-CA3 and PP-CA3 inputs developed and extinguished synchronously, suggesting that the changes of synaptic efficacy of different inputs of hippocampal CA3 area coordinated during discrimination learning.

Plasma membrane calcium ATPase in synaptic terminals of chick Edinger-Westphal neurons

The plasma membrane calcium ATPase pump (PMCA) is one of two major mechanisms known to be involved in extruding calcium from cells. The monoclonal antibody 5F10 was used to examine the distribution of PMCA in chick Edinger-Westphal neurons, a population of cholinergic preganglionic neurons whose cells bodies reside in the Edinger-Westphal nucleus in the brainstem and whose axons form synaptic terminals on parasympathetic neurons in the ciliary ganglion. Definitive PMCA immunoreactivity was undetectable in Edinger-Westphal cell bodies in the brainstem. In contrast, immunoreactivity for PMCA was robust in ciliary ganglia and resembled patterns of immunoreactivity for the synaptic vesicle antigen SV-2, suggesting that PMCA is expressed in Edinger-Westphal synaptic terminals. Moreover, PMCA immunoreactivity co-localized with immunoreactivity for enkephalin and substance P, two neuropeptides known to be expressed in Edinger-Westphal synaptic terminals. Fine structure studies revealed that PMCA immunoreactivity is associated with synaptic vesicles rather than the plasma membrane in Edinger-Westphal terminals. In immunodot assays, synaptic vesicles purified from Torpedo electric organ are also immunoreactive for PMCA as well as SV-2. Torpedo vesicles are negative for the sarcoplasmic/ endoplasmic reticulum ATPase, suggesting that the observed PMCA immunoreactivity is not associated with smooth endoplasmic reticulum. Immunoblot analysis confirmed that 5F10 recognizes a protein with the correct molecular mass for PMCA in tissue homogenates of chick cerebellum, chick ciliary ganglia, and Torpedo synaptic vesicles. These findings describe a previously unrecognized location for PMCA in the membranes of cholinergic synaptic vesicles. Relevance to previous data and possible functions are discussed.

Morphological diversity in terminals of W-type retinal ganglion cells at projection sites in cat brain

The morphological features of retinal terminals in cat brain were examined at sites where projections of W-type ganglion cells predominate. These included the parvicellular C laminae of the dorsal lateral geniculate nucleus, the ventral lateral geniculate nucleus, stratum griseum superficiale of the superior colliculus, and the suprachiasmatic nucleus. Positive identification of retinal terminals was achieved following anterograde transport of intravitreally injected native or wheat germ agglutinin-conjugated horseradish peroxidase. In contrast to the classic features of retinal terminals as defined from sites where X- and Y-type ganglion cells predominate, i.e. round synaptic vesicles, large profiles, and pale mitochondria, substantial numbers of terminals in W-cell rich areas were found to contain dark mitochondria. Synaptic vesicles, although consistently round, were typically smaller in terminals with dark mitochondria than in those with pale mitochondria. These findings indicate a diversity among terminals of W-cells and suggest that such terminals cannot be distinguished on the basis of limited morphological criteria.

Chronic ethanol treatment produces a selective upregulation of the NMDA receptor subunit gene expression in mammalian cultured cortical neurons

Our previous work has shown that chronic ethanol treatment upregulated NMDA receptor function and binding in mammalian cortical neurons. However, the potential molecular mechanisms involved in these phenomenon have yet to be elucidated. In the present study, using RNase protection assay, we investigated the effect of chronic ethanol treatment on the NMDA receptor subunits R1, R2A, and R2B mRNA levels in cultured cortical neurons. We found that chronic ethanol (50 mM, 5 days) exposure did not change the NMDA receptor R1 and R2A subunits mRNA levels. In contrast, the NMDA receptor R2B subunit mRNA level was increased by approximately 40% with respect to the control values. The levels of the R2B subunit mRNA returned to the control values following the removal of ethanol for 72 h. In order to determine the involvement of the NMDA receptors in the action of chronic ethanol exposure, we further investigated the effect of the NMDA receptor antagonists on the upregulation induced by chronic ethanol exposure. The results indicate that the increased R2B subunit level was reversed by concomitant chronic exposure of the cortical neurons to the NMDA receptor competitive (10 microM; CPP), and non-competitive (1 microM; MK-801) antagonists, but not by the non-NMDA receptor antagonist, CNQX (10 microM), or the L-type calcium channel blocker, nitrendipine (10 microM). Taken together, these results suggested that chronic ethanol exposure selectively upregulated the NMDA receptor subunit R2B mRNA level in cortical neurons, and this increased NMDA receptor gene expression appears to be a NMDA receptor mediated process. The altered NMDA receptor gene expression may be responsible for the observed upregulation of the NMDA receptor binding and function in the cortical neurons following chronic ethanol exposure.

Chronic ethanol treatment upregulates the NMDA receptor function and binding in mammalian cortical neurons

In the present study, we investigated the effects of chronic ethanol exposure on NMDA-mediated increase in intracellular calcium concentration ([Ca2+]i) by means of fluorescent measurement of [Ca2+]i with Fura-2AM in mammalian cortical cultured neurons, and the radioligand [3H]MK-801 binding to cortical neuronal membranes. Chronic exposure of the cortical neurons to ethanol (50 mM, 5 days) did not produce any change in the cell protein, morphological appearance, and the resting [Ca2+]i; however, it significantly enhanced the NMDA-mediated increase in [Ca2+]i. The EC50 value of NMDA was not significantly altered following chronic ethanol exposure, however, its Emax value was increased by approximately 45%. Furthermore, chronic ethanol exposure increased the specific [3H]MK-801 binding in cortical neuronal membrane preparation by approximately 30%. The enhancement of the NMDA-mediated increase in [Ca2+]i and the increase in [3H]MK-801 specific binding were reversed following 48 h ethanol withdrawal. Additionally, this enhanced NMDA response and the increased [3H]MK-801 specific binding were susceptible to blockade by the concomitant chronic exposure of the cortical neurons to the NMDA receptor competitive (20 microM CPP), and non-competitive (1 microM MK-801) antagonists, but not by the non-NMDA receptor antagonist, CNQX (10 microM), and the L-type calcium channel blocker, nitrendipine (10 microM). Taken together, these results suggest that chronic ethanol exposure upregulated the NMDA receptor function and binding in cortical cultured neurons, and this increased NMDA receptor function is a NMDA receptor-mediated process. This altered NMDA receptor function may be responsible for the chronic ethanol-induced behavioral consequences and withdrawal syndrome associated with chronic ethanol exposure.

Neurological deficit and extent of neuronal necrosis attributable to middle cerebral artery occlusion in rats. Statistical validation

BACKGROUND AND PURPOSE

Occluding a large intracranial artery in rats produces a brain lesion that grows in terms of an increase in both surface area and number of necrotic neurons. The present study investigated whether reperfusing the ischemic territory 30 to 60 minutes after the arterial occlusion would have a beneficial effect on either the clinical or the histological outcome of the lesion.

METHODS

One hundred four adult rats (including appropriate controls) were used; 97 had a middle cerebral artery occluded by inserting a nylon monofilament via the right external carotid artery. The arterial occlusion was transient in two groups and permanent in another; survival times were comparable for all groups. Control animals were subjected to a sham operation during which the artery was occluded for less than 1 minute. The outcome was evaluated by measuring the extent of the neurological deficit and the severity of the histological injury.

RESULTS

Mean neurological score and mean number of necrotic neurons in the cortex were more favorable after transient (30- to 60-minute) compared with permanent arterial occlusion (P < .005). Moreover, the correlation between mean neurological score and mean number of necrotic neurons was highly significant: r = .951; P < .001.

CONCLUSIONS

The histological effects of an intracranial arterial occlusion in the adult rat can be predicted on day 1 by the neurological score described in this report. Significant improvement can be obtained in these animals by reestablishing arterial flow 60 minutes or sooner after the ictus. The pattern of cortical pannecrosis observed after permanent occlusion (> or = 72 hours) was transformed into incomplete ischemic injury in most instances of transient occlusion.

Morphological study of the rostral interstitial nucleus of the medial longitudinal fasciculus in the monkey, Macaca mulatta, by Nissl, Golgi, and computer reconstruction and rotation methods

We have studied the morphology of silver-impregnated neurons (rapid Golgi technique) in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), a center involved in the control of vertical and torsional saccadic eye movements. This morphological study of riMLF neurons in the rhesus monkey was undertaken to further our understanding of the functional circuitry of the oculomotor system. Our study employed Nissl, Golgi, and computer-assisted methods. The cytoarchitectonic boundaries of the riMLF and its relationships to neighboring structures were determined in both Nissl and Golgi preparations. Five (I-V) distinct morphological types of riMLF neurons were distinguished in the Golgi impregnations on the basis of soma size, dendritic size, numbers of primary dendrites, number of dendritic branch points, as well as form, number, and distribution of dendritic appendages. Type I neurons impregnated most frequently and had the most extensive and highly branched dendritic tree. Type II neurons displayed thick dendrites with complex dendritic appendages, but the dendritic tree was much more compact than that of type I cells. Type III and type V cells had fusiform somas and relatively unbranched dendritic trees but differed greatly in size as well as dendritic morphology. The type IV cell was the smallest neuron and had many characteristics of the local interneurons found in other thalamic, subthalamic, hypothalamic and midbrain centers. The type V was the largest neuron, least frequently impregnated, and found only at rostral riMLF levels. Digitized reconstructions of each type of neuron were rotated by the computer, which revealed that the dendritic trees of types I, III, and V occupy a disk-like compartment in the riMLF neuropil. In contrast, the tree of types II and IV occupy a roughly spherical compartment. We suggest that three of the cell types are well suited for specific purposes: type II cells for receiving topographically organized inputs that contain spatial information, type I cells for short-lead burst neuron output to the motor neurons or other premotor centers, and type IV cells for inhibitory inputs to type I cells.

Chronic flurazepam treatment produces decreased efficacy of the benzodiazepine ligands and pentobarbital with gamma-aminobutyric acidA receptors in cortical neurons

The present study was designed to determine whether chronic benzodiazepine (BZ) agonist treatment alters the "set point" of the BZ pharmacological profile. This was achieved by investigating the modulation of gamma-aminobutyric acid (GABA)-mediated [36Cl-] influx by BZ ligands, as well as pentobarbital after chronic flurazepam treatment, in well characterized mammalian cortical neurons. Chronic flurazepam treatment (5 microM, 10 days) produced decreased efficacy of BZ agonists (diazepam and flunitrazepam) and inverse agonists (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3'-carboxylate and ethyl-beta-carboline-3-carboxylate), as measured by GABA-induced [36Cl-] influx. The chronic flurazepam treatment, although not altering their EC50/IC50 values, decreased the Emax/-Emax values. Furthermore, the decreased efficacy was reversed after a 72-hr withdrawal, and by concomitant exposure of the neurons to Ro15-1788 (ethyl-8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5 alpha][1,4]- BZ-3-carboxylate), a BZ receptor antagonist, but not by R 5135 (3 alpha-hydroxy-16-imino-5 beta-17-androstan-11-one; a GABA receptor antagonist) and pircrotoxin (a channel blocker). The chronic flurazepam treatment also produced uncoupling between pentobarbital and BZ receptor sites, and decreased the efficacy of pentobarbital to enhance GABA-mediated [36Cl-] influx, events also reversed at 72-hr withdrawal and concomitant exposure to Ro15-1788. Chronic flurazepam treatment-induced uncoupling and decreased efficacy of BZ agonists was not reversed by the GABAA receptor antagonist, R 5135, or channel blocker, picrotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Development pattern of the GABAA-benzodiazepine receptor ionophore complex in primary cultures of cortical neurons

The development pattern of the GABAA/benzodiazepine (BZ) receptor ionophore complex was characterized in mammalian cortical cultured neurons utilizing radioligand binding and GABA-induced 36Cl-influx. The specific binding of [3H]flunitrazepam, [3H]Ro15-1788 and [3H]Ro15-4513 increased with time from day 3 to day 21. The EC50 value and Emax of the GABA, muscimol and pentobarbital to enhance [3H]-flunitrazepam binding did not change during the development. Furthermore, GABA-induced 36Cl- influx also did not change during development from day 3 to day 21. However, the potency of ligands that bind to type-1 BZ receptors (alprazolam, zolpidem and C1218,872) to inhibit [3H]flunitrazepam binding increased from day 7 to day 21. Taken together, these data suggest the presence of type-II BZ receptors in early stages of the development which appears to change to type-I BZ receptors with age in the cortical neurons in culture.