[Neurobehavioral effects of explosion exposure on acute and chronic traumatic brain injury in rats]

Objective: To explore the effect of nerve injury in rats by neurobehavioral experiments, in order to provide a model and idea for further clarification of the traumatic brain injury mechanism under explosion exposure. Methods: From May 2021 to August 2022, 160 SPF male rats were randomly divided into four groups, including control group, 60 kPa group (low intensity group), 90 kPa group (medium intensity group) and 120 kPa group (high intensity group). The blast induced traumatic brain injury (bTBI) model of rats was established by using the shock tube platform to simulate the shock wave parameters of the explosion overpressure of 60 kPa, 90 kPa and 120 kPa. Acute observation was carried out after 24 h and 7 d of explosive exposure, and chronic recovery observation was carried out after 28 d and 90 d. The time effect of shock wave brain injury in different situations was discussed by open field, light dark test, active avoidance test. Finally, the results of brain injury in rats were detected by pathological tissue staining. Results: After 24 h explosion exposure, compared with the control group, the rest time of rats in low and high intensity groups increased, the total movement distance decreased, and the number of visits to the camera obscura decreased, with statistical significance (P<0.05). After 7 days of exposure, compared with the control group, the rest time of rats in high intensity group increased, and the number of visits to the obscura decreased, with statistical significance (P<0.05). After 28 and 90 days of exposure, compared with the control group, there were no significant differences in rest time, total exercise distance and times of visiting the camera obscura in all intensity groups (P>0.05). After 24 h of explosive exposure, compared with the control group, the cell morphology of rats in each intensity group was normal, and no inflammatory cell infiltration was observed. Conclusion: In the acute phase (24 h) of blast exposure, rats have no desire to explore the outside world, and shock wave exposure may damage the neurological function of rats.

[Clinical validation of the 2020 diagnostic approach for pediatric autoimmune encephalitis in a single center]

Objective: To evaluate the value of the 2020 diagnostic criteria (Cellucci criteria) for pediatric autoimmune encephalitis (AE) in children with suspected AE in a single center. Methods: The clinical data of 121 children hospitalized at the First Affiliated Hospital of Zhengzhou University from October 2019 to October 2021, with a diagnosis of suspected AE, were retrospectively collected and analyzed. The children were divided into definite antibody-positive AE (dAPAE), probable antibody-negative AE (prANAE), possible AE (pAE) and non-AE groups according to the Chinese expert consensus and the Graus criteria. A new diagnosis was made according to the Cellucci criteria which was compared with the clinical diagnosis to evaluate the diagnostic value of the Cellucci criteria. The Mann-Whitney U test, Kruskal-Wallis test, and χ² test were used to compare the differences among groups. The sensitivity and specificity were used to evaluate efficacy of the Cellucci criteria. Results: Among the 121 children, 72 were males and 49 were females, with an age of 10.3 (6.5, 14.0) years at disease onset. There were 99 cases diagnosed as AE according the clinical diagnosis (58 males and 41 females), of which 43 cases were diagnosed as dAPAE, 14 cases as prANAE and 42 cases as pAE, and the other 22 cases were not AE (14 males and 8 females). The top 2 initial symptoms in the 99 children with AE were seizures (53 cases, 53.5%) and abnormal mental behaviors (35 cases, 35.4%). And the most common symptoms during the course of the disease were abnormal mental behaviors (77 cases, 77.8%) and seizures (64 cases, 64.6%). There were statistically differences in the incidence of consciousness disorders, autonomic dysfunctions during the course of the disease and the length of hospitalization among the 4 groups (χ²=21.63, 13.74, H=22.60, all P<0.05). Ninety-six of the 121 children were tested for AE-related antibodies, of which 45 cases (46.9%) were antibody-positive. According to the Cellucci criteria, 42 cases were diagnosed as dAPAE, 34 cases as prANAE and 14 cases as pAE. Compared with the clinical diagnosis, the sensitivity of the Cellucci criteria for the diagnosis of the 3 types of AE were 93.02%, 92.86% and 87.88%, and the specificity were 96.23%, 74.39% and 86.36%, respectively. Conclusions: The Cellucci criteria has a high sensitivity and specificity for the diagnosis of pAE and dAPAE in the clinical management of children with suspected AE, while a high sensitivity but low specificity for the diagnosis of prANAE. Therefore, it is recommended to apply the Cellucci criteria selectively in clinical practice according to the actual situation, especially in the diagnosis of prANAE.

Observation of Spin Splitting Torque in a Collinear Antiferromagnet RuO_{2}

Current-induced spin torques provide efficient data writing approaches for magnetic memories. Recently, the spin splitting torque (SST) was theoretically predicted, which combines advantages of conventional spin transfer torque (STT) and spin-orbit torque (SOT) as well as enables controllable spin polarization. Here we provide the experimental evidence of SST in collinear antiferromagnet RuO_{2} films. The spin current direction is found to be correlated to the crystal orientation of RuO_{2} and the spin polarization direction is dependent on (parallel to) the Néel vector. These features are quite characteristic for the predicted SST. Our finding not only presents a new member for the spin torques besides traditional STT and SOT, but also proposes a promising spin source RuO_{2} for spintronics.

Role of clinical data and multidetector computed tomography findings in acute superior mesenteric artery embolism

BACKGROUND

Superior mesenteric artery embolism (SMAE) has acute onset and fast progression, which seriously threatens the life of patients. Multidetector computed tomography (MDCT) is one of the most important diagnostic methods for SMAE, which plays an important role in the diagnosis and prognosis of SMAE.

AIM

To evaluate the value of combined clinical data and MDCT findings in the diagnosis of acute SMAE and predict the risk factors for SMAE-related death.

METHODS

Data from 53 SMAE patients who received abdominal MDCT multi-phase enhancement and superior mesenteric artery digital subtraction angiography examinations were collected. Univariate cox regression and multivariate cox model were used to analyze the correlation between death risk and clinical and computed tomography features in SMAE patients.

RESULTS

Univariate Cox regression model showed that intestinal wall thinning, intestinal wall pneumatosis, blood lactate > 2.1 mmol/L and blood pH < 7.35 increased the risk of death in patients with SMAE. After adjusting for age, sex, embolic involvement length and embolic distribution region, multivariate Cox regression model I showed that blood lactate > 2.1 mmol/L (HR = 5.26, 95%CI: 1.04-26.69, P = 0.045) and intestinal wall thinning (HR = 9.40, 95%CI: 1.05-83.46, P = 0.044) were significantly increases the risk of death in patients with SMAE.

CONCLUSION

For patients with SAME, increased blood lactate and intestinal wall thinning are the risk factors for death; hence, close monitoring may reduce the mortality rate. Clinical observation combined with MDCT signs can significantly improve SMAE diagnosis.

[Evaluation of developmental toxicity of ammonium dinitramide by micromass culture and embryonic stem cells models]

Objective: To evaluated the potential developmental toxicity and teratogenicity of ammonium dinitroamide (ADN) by micromass test (MM Test) and embryonic stem cell test models. Methods: In September 2018, rat embryos were isolated and limb bud cells were collected. The limb bud cells were treated with different concentrations of ADN (0, 312.50, 625.00, 1250.00, 2500.00, 5000.00, 10000.00 μg/ml) . Half proliferation inhibitory concentration and half differentiation inhibitory concentration were calculated and the teratogenic effects were evaluated according to the criteria. For the embryonic stem cell test, the effects of different concentrations of ADN (0, 39.06, 78.13, 156.25, 312.50, 625.00, 1250.00, 2500.00 μg/ml) on the differentiation of mouse embryonic stem cells (mESCs) into myocardial cells and the cytotoxicity of mESCs and 3T3 cells were detected. The embryonic toxicity was evaluated according to the criteria. In this study, both 5-fluorouracil (5-FU) , a known strong embryonic toxic drug, and penicillin-G (P-G) , a non-embryonic toxic drug, were used to verify the effectiveness of the model, and the validated test model was applied to evaluate the embryonic toxicity of ADN. Results: In the MM Test, the inhibition rates of proliferation and differentiation of limb bud cells in ADN groups were higher than that in control group (P<0.05) . And the half proliferation inhibitory concentration and half differentiation inhibitory concentration of ADN on limb bud cells were 7480.32 and 4526.09 μg/ml, respectively. ADN was determined to be non-teratogenic by standard. In the embryonic stem cell test, the inhibition rates of mESCs proliferation in ADN groups were higher than that in control group, and the inhibition rates of 3T3 cells in 156.25, 312.50, 625.00, 1250.00, 2500.00 μg/ml ADN groups were higher than that in control group (P<0.05) . The half proliferation inhibitory concentration and half differentiation inhibitory concentration of ADN on mESCs were 1851.73 and 1796.39 μg/ml, respectively, and the half proliferation inhibitory concentration on 3T3 cells was 3334.35 μg/ml. ADN was determined to be non-embryotoxic by standard. Conclusion: After evaluation by MM Test and embryonic stem cell models, ADN has no embryo toxicity and is a non-teratogenic substance.

Interferometric control of magnon-induced nearly perfect absorption in cavity magnonics

The perfect absorption of electromagnetic waves has promoted many applications, including photovoltaics, radar cloaking, and molecular detection. Unlike conventional methods of critical coupling that require asymmetric boundaries or coherent perfect absorption that require multiple coherent incident beams, here we demonstrate single-beam perfect absorption in an on-chip cavity magnonic device without breaking its boundary symmetry. By exploiting magnon-mediated interference between two internal channels, both reflection and transmission of our device can be suppressed to zero, resulting in magnon-induced nearly perfect absorption (MIPA). Such interference can be tuned by the strength and direction of an external magnetic field, thus showing versatile controllability. Furthermore, the same multi-channel interference responsible for MIPA also produces level attraction (LA)-like hybridization between a cavity magnon polariton mode and a cavity photon mode, demonstrating that LA-like hybridization can be surprisingly realized in a coherently coupled system.

High Curie temperature and carrier mobility of novel Fe, Co and Ni carbide MXenes

Two-dimensional (2D) magnets with room temperature ferromagnetism and semiconductors with moderate band gap and high carrier mobility are highly desired for applications in nanoscale electronics and spintronics. By performing the first-principles calculations, we investigate novel Fe, Co, Ni carbide based pristine (M₂C) and functionalized (M₂CT₂, T: F, O, OH) MXenes. Our calculations show that Fe₂C, Co₂C, Ni₂C, Fe₂CF₂, Fe₂CO₂, Fe₂C(OH)₂, Co₂CF₂, Co₂C(OH)₂ and Ni₂CF₂ are dynamically and mechanically stable. More importantly, Fe₂C, Co₂C, Fe₂CF₂ and Fe₂C(OH)₂ exhibit intrinsic ferromagnetism (magnetic moments 2-5μ_B per unit cell). Monte Carlo simulations suggest high Curie temperatures of 590 and 920 K for Fe₂C and Fe₂CF₂, respectively, at the HSE06 level owing to the large spin magnetic moments and strong ferromagnetic coupling. Based on the deformation potential theory, we predict high and anisotropic hole mobility (0.2-1.4 × 10⁴ cm² V^-1 s^-1) for semiconducting Fe₂CO₂ and Co₂C(OH)₂. Additionally, Ni₂CF₂ demonstrates highly anisotropic electron mobility together with a direct band gap. Our results further show the effectiveness of surface functionalization in modulating the electronic and magnetic properties and broadening the properties of MXenes to achieve long-range intrinsic ferromagnetism well above room temperature and high carrier mobility.

[Surgical treatment strategy for endograft infection after thoracic endovascular aortic repair]

Objective: To examine the results of surgical treatment for endograft infection after thoracic endovascular aortic repair (TEAVR). Methods: Clinical data of 7 patients underwent surgical treatment for endograft infection after TEAVR at Department of Cardiothoracic Surgery, Changhai Hospital, the Navy Medical University between January 2016 and December 2018 were analyzed retrospectively. There were 6 males and 1 female, aging (51.5±16.7) years (range: 25 to 68 years). The origin of the aortic disease was descending aortic aneurysm in 5 cases, and Stanford B aortic dissection in 2 cases. Abdominal aorta below the level of the diaphragm was not involved in all patients. Two patients received "chimney technology" for left subclavian artery procedures. Time to infection was 5(3) months (M(Q(R))) (range: 1 to 24 months). Aortic endograft infection was diagnosed with a combination of microbiology (positive blood cultures, except one with mycotic), radiological evidence and clinical evidence of sepsis. Two patients suffered from aorto-esophageal fistula received emergency surgery, others were treated with elective surgery. Extra-anatomic prosthetic graft bypass was used for reconstruction of aorta, infected endogarft and aorta was removed, sac drainage was performed. Aorto-esophageal fistula was procedured according to the degree of lesions. All patients received antibiotics with specialist advice for 6 to 8 weeks. Results: One patient died due to septic shock. In the follow-time (range: 6 to 24 months), 1 patient suffered from thoracic infection in 3 months after surgery, an other patient got iliac abscess after a month. Conclusions: Endograft infection after TEAVR is high risk but may be curative. Appropriate selection of patients for infected endograft explantation could get a satisfied results.

[Medical staff's exposure to solid particles and health impact survey]

Objective: To investigate the current situation of exposure of solid particles in medical staff and the occurrence of related diseases, and to understand the distribution characteristics of occupational exposure and the influencing factors. Methods: In August 2016, the stratified cluster sampling method was adopted to select three tertiary general hospitals with different regions, different administrative levels and departments in Shandong Province. A face-to-face questionnaire survey was conducted on the basic situation of the staff of the hospital, the status of exposure to occupational hazards and the health effects. Two-class logistic regression analysis was used to analyze the relationship between medical staff's solid particle contact and occupational health effects. In August 2016, the stratified cluster sampling method was adopted to select three tertiary general hospitals with different regions, different administrative levels and departments in Shandong Province, which were in contact with the basic conditions and occupational hazards of the staff of the hospital. Current situation and health impacts were conducted face-to-face questionnaires. Two-class logistic regression analysis was used to analyze the relationship between medical staff's solid particle contact and occupational health effects. Results: The overall contact rate of solid particles of medical staff was 41.5% (1843/4 446) , and the solid particles with the highest contact rate were 28.2% (1254/4 446) of talc dust. There was a statistically significant difference in the contact rate of solid particles between medical staff of different occupations, current working age, education and hospital type (χ(2)=76.30, 41.26, 26.16, 188.97, P<0.05) . There were significant differences in the conditions and types of solid particles in different departments (χ(2)=740.23, P<0.05) . Compared with the control group, the incidence of allergic asthma, chronic tracheobronchitis and dermatitis was higher in the contact group medical staff (P<0.05) . Contact with zirconia dust, talc dust, cotton dust is a risk factor for dermatitis in medical staff (OR=2.09, 1.45, 1.34) ; exposure to zirconia dust and cotton dust is a risk factor for chronic tracheobronchitis in medical staff (OR=2.38, 1.66) ; exposure to zirconia dust, gypsum dust is a risk factor for allergic asthma in medical staff (OR=3.90, 1.52) . Conclusion: The contact rate of solid particles in medical staff is high, and there are many types of contact. Frequent contacted with solid particles is a dangerous cause of related diseases. The working environment of medical staff should be further monitored and be strengthen the targeted protective measures and regulatory systems for the exposure of medical personnel to solid particles.

Aberrant brain functional connectome in patients with obstructive sleep apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is accompanied by widespread abnormal spontaneous regional activity related to cognitive deficits. However, little is known about the topological properties of the functional brain connectome of patients with OSA. This study aimed to use the graph theory approaches to investigate the topological properties and functional connectivity (FC) of the functional connectome in patients with OSA, based on resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

Forty-five male patients with newly diagnosed untreated severe OSA and 45 male good sleepers (GSs) underwent a polysomnography (PSG), clinical evaluations, and rs-fMRI scans. The automated anatomical labeling (AAL) atlas was used to construct the functional brain connectome. The topological organization and FC of brain functional networks in patients with OSA were characterized using graph theory methods and investigated the relationship between functional network topology and clinical variables.

RESULTS

Both the patients with OSA and the GSs exhibited high-efficiency "small-world" network attributes. However, the patients with OSA exhibited decreased σ, γ, Eglob; increased Lp, λ; and abnormal nodal centralities in several default-mode network (DMN), salience network (SN), and central executive network (CEN) regions. However, the patients with OSA exhibited abnormal functional connections between the DMN, SN, and CEN. The disrupted FC was significantly positive correlations with the global network metrics γ and σ. The global network metrics were significantly correlated with the Epworth Sleepiness Scale (ESS) score, Montreal Cognitive Assessment (MoCA) score, and oxygen desaturation index.

CONCLUSION

The findings suggest that the functional connectome of patients with OSA exhibited disrupted functional integration and segregation, and functional disconnections of the DMN, SN, and CEN. The aberrant topological attributes may be associated with disrupted FC and cognitive functions. These topological abnormalities and disconnections might be potential biomarkers of cognitive impairments in patients with OSA.

[Cross-sectional survey of autism spectrum disorders in children aged 0-6 years in Hainan province]

Objective: To understand the prevalence of autism spectrum disorders (ASD) in children aged 0-6 years old and influencing factors in Hainan province. Methods: A total of 37 862 children aged 0-6 years were selected from 18 counties in Hainan province for a screening by using questionnaire of"warning signs in child development", then field diagnosis was made, and general descriptive statistic analysis was conducted. The prevalence of ASD and related factors were analyzed with χ(2) test and unconditional logistic regression model. Results: Among 37 862 children aged 0-6 years, 235 were diagnosed with ASD, the prevalence of ASD was 0.62% (0.99% in boys, 0.17% in girls), the differences was significant (χ(2)=101.91, P=0.000). The prevalence of ASD increased with age (χ(2)=288.62, P=0.000). The prevalence of ASD was significantly higher in urban area than in other areas (χ(2)=114.77, P=0.000). Factors such as full term pregnancy or not, neonatal asphyxia, father's characteristics, father's habit of chewing areca or smoking, mother's general mood, and mother's induced abortion history were the influencing factors for ASD. Conclusion: The prevalence of ASD in children aged 0-6 years was high in Hainan and was influenced by genetic factors, pregnancy and delivery process, parents unhealthy habit before and during pregnancy and other factors.

Disrupted small-world brain functional network topology in male patients with severe obstructive sleep apnea revealed by resting-state fMRI

PURPOSE

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that can damage cognitive function. However, the functional network organization remains poorly understood. The aim of this study was to investigate the topological properties of OSA patients using a graph theoretical analysis.

PATIENTS AND METHODS

A total of 30 male patients with untreated severe OSA and 25 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (MRI) examinations. Clinical and cognitive evaluations were conducted by an experienced psychologist. GRETNA (a toolbox for topological analysis of imaging connectomics) was used to construct the brain functional network and calculate the small-world properties (γ, λ, σ, E_glob, and E_loc). Relationships between these small-world properties and clinical and neuropsychological assessments were investigated in OSA patients.

RESULTS

The networks of both OSA patients and GSs exhibited efficient small-world topology over the sparsity range of 0.05-0.40. Compared with GSs, the OSA group had significantly decreased γ, but significantly increased λ and σ. The OSA group's brain network showed significantly decreased E_glob (P<0.05) over the sparsity range of 0.09-0.15, but significantly increased E_loc over the sparsity range of 0.23-0.40. In OSA patients, γ was significantly negatively correlated with apnea-hypopnea index (AHI; r=-0.326, P=0.015) and Epworth Sleepiness Scale (ESS; r=-0.274, P=0.043), λ was significantly positively correlated with AHI (r=0.373, P=0.005) and ESS (r=0.269, P=0.047), and σ was significantly negatively correlated with AHI (r=-0.363, P=0.007) and ESS (r=-0.295, P=0.029).

CONCLUSION

Our results suggest that the high degree of local integration and integrity of the brain connections in OSA patients may be disrupted. The topological alterations of small-world properties may be the mechanism of cognitive impairment in OSA patients. In addition, σ, γ, and λ could be used as a quantitative physiological index for auxiliary clinical diagnoses.

Combretastatin A-4 efficiently inhibits angiogenesis and induces neuronal apoptosis in zebrafish

Cis-stilbene combretastatin A-4 (CA-4) and a large group of its derivant compounds have been shown significant anti-angiogenesis activity. However the side effects even the toxicities of these chemicals were not evaluated adequately. The zebrafish model has become an important vertebrate model for evaluating drug effects. The testing of CA-4 on zebrafish is so far lacking and assessment of CA-4 on this model will provide with new insights of understanding the function of CA-4 on angiogenesis, the toxicities and side effects of CA-4. We discovered that 7-9 ng/ml CA-4 treatments resulted in developmental retardation and morphological malformation, and led to potent angiogenic defects in zebrafish embryos. Next, we demonstrated that intraperitoneal injection of 5, 10 and 20 mg/kg CA-4 obviously inhibited vessel plexus formation in regenerated pectoral fins of adult zebrafish. Interestingly, we proved that CA-4 treatment induced significant cell apoptosis in central nervous system of zebrafish embryos and adults. Furthermore, it was demonstrated that the neuronal apoptosis induced by CA-4 treatment was alleviated in p53 mutants. In addition, notch1a was up-regulated in CA-4 treated embryos, and inhibition of Notch signaling by DAPT partially rescued the apoptosis in zebrafish central nervous system caused by CA-4.

Seebeck rectification enabled by intrinsic thermoelectrical coupling in magnetic tunneling junctions

An intrinsic thermoelectric coupling effect in the linear response regime of magnetic tunneling junctions (MTJ) is reported. In the dc response, it leads to a nonlinear correction to Ohm's law. Dynamically, it enables a novel Seebeck rectification and second harmonic generation, which apply for a broad frequency range and can be magnetically controlled. A phenomenological model on the footing of the Onsager reciprocal relation and the principle of energy conservation explains very well the experimental results obtained from both dc and frequency-dependent transport measurements performed up to GHz frequencies. Our work refines previous understanding of magnetotransport and microwave rectification in MTJs. It forms a new foundation for utilizing spin caloritronics in high-frequency applications.

Exotic meson decay to omegapi0pi-

A partial-wave analysis of the mesons from the reaction pi(-)p --> pi(+)pi(-)pi(-)pi(0)pi(0)p has been performed. The data show b(1)pi decay of the spin-exotic states pi(1)(1600) and pi(1)(2000). Three isovector 2(-+) states were seen in the omegarho(-) decay channel. In addition to the well known pi(2)(1670), signals were also observed for pi(2)(1880) and pi(2)(1970).

Adsorption of triplet O(2) on Si(100): the crucial step in the initial oxidation of a silicon surface

It has long been understood that a precursor mediated chemisorption is a significant part of the dynamics for the adsorption of O(2) on Si(100), which is a much studied model system of surface reaction with considerable technological relevance. However, theoretical studies on the interaction between O(2) and Si(100) have been focused on the excited singlet state of O2 and unable to explain the observations in surface scattering experiments. We demonstrate by first principles calculations that such a focus is misplaced. In reality, triplet O(2) can also react with Si(100), after overcoming small barriers, and its reaction paths provide a full account for experiments. Our results highlight the important role played by triplet O(2) in surface oxidation.

Differential regulation of beta-arrestin 1 and beta-arrestin 2 gene expression in rat brain by morphine

Beta-arrestins are a family of regulatory and scaffold proteins functioning in signal transduction of G protein-coupled receptors including opioid receptors. Upon agonist stimulation, beta-arrestins bind to opioid receptors phosphorylated by G protein-coupled receptor kinases and promote receptor internalization and desensitization. Studies indicated that beta-arrestins are required in the development of morphine tolerance in mice. In the current study, we investigated the potential regulatory effects of morphine administration on beta-arrestin 1 and beta-arrestin 2 mRNA levels in different brain regions in rat using in situ hybridization method. Our results showed that the acute morphine administration (10 mg/kg) resulted in approximately 30% reduction in both beta-arrestin 1 and beta-arrestin 2 mRNA levels in hippocampus while the chronic morphine treatment (10 mg/kg, b.i.d., for 9 days) caused no significant change in level of either beta-arrestin mRNA. In locus coeruleus, both acute and chronic morphine treatments resulted in significant decreases (over 50%) in beta-arrestin 1 mRNA level but failed to induce any change in the level of beta-arrestin 2 gene expression. The acute morphine administration had no significant effect on beta-arrestin 1 or beta-arrestin 2 mRNA level in periaqueductal gray and cerebral cortex. However, after chronic morphine treatment, beta-arrestin 2 mRNA level decreased by 40% in periaqueductal gray and increased by 25% in cerebral cortex, in strong contrast to the unchanged beta-arrestin 1 mRNA level in these two brain regions. Furthermore, spontaneous or naloxone-precipitated withdrawal of morphine that did not affect the level of beta-arrestin 1 mRNA resulted in an aberrant increase (100% over control) in beta-arrestin 2 mRNA level in hippocampus. Our results thus demonstrated for the first time that opiate administration regulates level of beta-arrestin mRNAs in brain and the expression of beta-arrestin 1 and beta-arrestin 2 subtypes is differentially regulated in locus coeruleus, periaqueductal gray, and cerebral cortex by morphine. These data suggest that beta-arrestin 1 and beta-arrestin 2 may play different roles in the development of opioid tolerance and dependence.

Observation of exotic meson production in the reaction pi- p --> eta'pi- p at 18 GeV/c

An amplitude analysis of an exclusive sample of 5765 events from the reaction pi- p-->eta'pi- p at 18 GeV/c is described. The eta'pi- production is dominated by natural parity exchange and by three partial waves: those with J(PC) = 1(-+), 2(++), and 4(++). A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to eta'pi-. The dominant, exotic (non- qq) 1(-+) partial wave is shown to be resonant with a mass of 1.597+/-0.010(+0.045)(-0.010) GeV/c2 and a width of 0.340+/-0.040+/-0.050 GeV/c2. This exotic state, the pi1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states.

[Effects of muscle spindle afferents on the regulation of respiration in rabbit]

Effect of muscle spindle afferent invoked by intraarterial injection of succinylcholine (Sch) on respiration was assessed by changes in unit discharge of respiration related neurons and phrenic nerve of 63 anesthetized, bilaterally vagotomized and artificially ventilated rabbits. The results are as follows. (1) Intra~arterial injection of Sch prolonged inspiratory duration (Ti) or decreased expiratory duration (Te) and augmented respiratory frequency (RF). (2) 66% (37/56) of the medullary inspiratory neurons were excited and 10/17 of the expiratory neurons were inhibited by intraarterial injection of Sch, reaching maximum respectively at 1 2 and 2 3 min after injection, while non-respiration related neurons were not affected. (3) This effect of Sch was suppressed or abolished when muscle spindles were destroyed by intramuscular injection of bupivacaine.

Effects of simulated microgravity on immunoreactivity of conjugated-ubiquitin of muscle spindles of soleus in rats

It is well known that the muscle spindle is a receptor of muscle's tension and length, it plays an important role in maintaining the muscle's tension. The aim of the present study is to compare the cross-section area (CSA) and the immunoreactivity of conjugated-ubiquitin in soleus extrafusal and intrafusal fibers after simulated-microgravity in order to demonstrate the role of muscle spindle in muscle atrophy induced by simulated microgravity.

[Role of red nucleus in inhibiting nociceptive responses of rat spindle afferent]

Using extracellular recording techniques, the effect of excitation of red nucleus (RN) on C-responses of wide dynamic range (WDR) neurons and the roles of RN in the inhibitory effect of spindle afferent activated by succinycholine (SCH) on C-responses of WDR neurons were studied. Stimulation of RN caused a significant reduction of nociceptive responses of WDR neurons, which was significantly attenuated by intravenous cyproheptadine and contralateral lesion of RN. These results suggest that the inhibitory effect on nociceptive responses of WDR neurons caused by RN stimulation was partly mediated by 5-HT and RN plays an important role in analgesia induced by the muscle spindle afferent activity.

Reversal of the static component of spindle potential by imposed depolarizing current in the frog muscle spindle

The static component of the spindle potential provoked during stretch of isolated muscle spindles of the frog was reversed during the application of depolarizing currents ranging from 0.2 to 5 nA in normal Ringer solution and also in Na+-free Ringer solution. In the same range of current intensities, spontaneous rhythmic hyperpolarizations due to [Ca2+]i-activated GK, an attenuation of membrane impedance, and an anomalous decrease in amplitude of the afferent spikes were observed. All 4 phenomena were abolished by K+ channel blockers (10 mM CsCl, 1-2 mM 4-aminopyridine (4-AP), or 20 mM tetraethylammonium chloride (TEA], Ca2+ channel blockers (5-10 mM CoCl2, MnCl2, 1-2 mM CdCl2 or 0.5 mM verapamil) or 0.1 mM quinine. The amplitude of the static component of the spindle potential was markedly increased at threshold concentration of the K+ channel blockers (5 mM CsCl, 0.1-0.5 mM 4-AP or 5-10 mM TEA), but the component disappeared at that of the Ca2+ channel blockers. The rhythmic hyperpolarizations are associated with the spindle potential, except for its dynamic component, which often triggers a hyperpolarizing deflection. We suggest that both the static component of the spindle potential and rhythmic hyperpolarizations are due to GK(Ca) in the intracapsular axon, either along the terminal or at the branching nodes, or both; and that the receptor potential contributes to, but is not the same as, the spindle potential.