Impact of Bullying Victimization on Chinese College Students' Suicidal Tendency: The Moderating Effect of Teachers' Emotional Support and Family Support

Objective

To explore the influence of bully victims on the suicidal tendencies of college students, and the moderating role of teacher emotional support and family support in the relationship between bully victims and college students' suicidal tendencies, in order to provide a reference for the effective intervention of college students' suicide behavior.

Methods

Based on a survey of 15,560 college students. Multiple stepwise regression and Interaction analysis explore the impact of the bully victimization on college students' suicidal tendencies and the moderating role of family support and teacher emotional support in the relationship between the bully victim and college students' suicidal tendencies.

Results

This study found that the Suicidal Tendencies score of college students was 19.79 points, indicating that some college students have a risk of suicidal tendencies; secondly, verbal bullying (β = 0.084, P <0.001), physical bullying (β = 0.222, P <0.001) and social relationship bullying (β = 0.122, P <0.001) have a positive and significant impact on the suicidal tendencies of college students; in addition, family support and teacher emotional support have a significant regulatory effect on the bully victim and college students Suicidal Tendencies and family support. The regulating effect was significantly higher than that of teacher emotional support.

Conclusion

Chinese college students have the risk of suicidal tendencies; peer bullying victimization is an important reason for affecting college students' suicidal tendencies, teacher emotional support is a protective factor for bully victims to affect college students' suicidal tendencies, and family support has a significant moderating effect on the bully victim and college students' suicidal tendencies. Therefore, it is necessary to actively adopt home-school linkage and home-school communication to reduce campus violence and increase the psychological resilience of college students.

Research on collaborative development mechanism of multiple stakeholders in medical institutions based on rough set

Reducing doctor-patient conflict is an important part of coordinating doctor-patient disputes and easing doctor-patient relationship, which is conducive to building a harmonious medical environment and promoting the healthy development of medical undertakings. This paper constructs a multi-decision-maker mixed conflict model based on rough set theory, puts forward the matrix operation expression of the conflict degree theory in the Pawlak model, and gives a more objective and scientific evaluation function. Combined with hot issues of doctor-patient conflict, the proposed multi-decision-maker mixed conflict model is applied to doctor-patient conflict, examines the doctor-patient relationship in the medical institution system from multiple internal perspectives, and calculates feasible solutions in the conflict system. The results show that high medical quality, high standardize medication, high institutional efficiency, high staff efficiency, high hospital benefits, high hospital revenue, medium employee development, medium equipment development, or high medical quality, high standardize medication, high institutional efficiency, medium staff efficiency, medium hospital benefits, high hospital revenue, high employee development, and high equipment development are important conditions for building a harmonious medical environment and reducing doctor-patient conflicts.

Middle-aged and older people's preference for medical-elderly care integrated institutions in China: a discrete choice experiment study

BACKGROUND

With the continuing impact of the aging population, medical-elderly care integrated institutions, as a way to bear the pressure of medical and elderly care, effectively ensure the quality of life of the elderly in their later years.

OBJECTIVES

To explore the preferences of medical-elderly care integrated institutions among Chinese middle-aged and older people and to provide a reference for establishing elderly-oriented development of medical-elderly care integrated institutions.

METHODS

In this study, a discrete choice experiment (DCE) was used to investigate the preferences of people aged 45 years and older in medical-elderly care integrated institutions in China from October 20, 2022, to November 10, 2022. A mixed logit regression model was used to analyze the DCE data. Participants' willingness to pay for each attribute was also calculated.

RESULTS

Data from 420 participants who provided valid responses were included in the analysis. In terms of the choice preference, moderate service quality (vs. poor service quality: β = 1.707, p < 0.001, 95% CI 1.343 ~ 2.071) and high medical technology level (vs. low medical technology level: β = 1.535, p < 0.001, 95% CI 1.240 ~ 1.830) were the most important attributes to middle-aged and older people, followed by monthly cost, environmental facilities, the convenience of transportation, and entertainment activities. Regarding the willingness to pay, participants were more willing to pay for service quality and medical technology level than for other attributes. They were willing to pay $3156 and $2838 more for "poor service quality" and "low medical technology level," respectively, to receive "moderate service quality " (p = 0.007, 95% CI 963 ~ 5349) and "high medical technology level" (p = 0.005, 95% CI 852 ~ 4824).

CONCLUSIONS

The state should attach great importance to the development of medical-elderly care integrated services industry, actively optimize the model of the medical-elderly care integrated service, improve the facilities, and create a healthy environment. At the same time, give full play to the role of medical insurance, long-term care insurance, and commercial insurance, so as to improve the comprehensive quality of life of the elderly.

PUBLIC CONTRIBUTION

The design of the experimental selection was guided by 10 experts in the field, 5 Chinese government officials, and interviews and focus group discussions, without whose participation this study would not have been possible.

Pathways of Media Contact to Health Literacy in Middle-Aged and Older People: The Chain Mediation Effect of Perceived Social Support and Self-Efficacy

Objective

To understand the status of media exposure, social support, self-efficacy, and health literacy among middle-aged and older adults in China, and explore the impact path of media exposure on the health literacy of this population, providing a reference for promoting their physical and mental health.

Methods

From July to November 2022, a multi-stage random sampling method was employed to survey 16,938 Chinese middle-aged and older adults aged 46 and above. Structural equation modeling and statistical analysis were conducted using LISREL 8.8 and Mplus 8.3 software.

Results

The average score for media exposure among Chinese middle-aged and older adults was (18.55±5.36), perceived social support was (60.68±12.51), self-efficacy was (28.76±5.40), and health literacy was (35.49±6.05). Statistical results revealed that media exposure has a positive impact on the health literacy of middle-aged and older adults, with a direct effect of 0.091 (p < 0.001). Mediation analysis showed that media exposure can affect the health literacy of this population through the independent mediating effects of perceived social support (β = 0.013, p < 0.001) and self-efficacy (β = 0.029, p < 0.001), as well as through a chain mediation effect involving perceived social support and self-efficacy (β = 0.015, p < 0.001).

Conclusion

As a pathway for health information dissemination, media exposure plays a crucial role in the intervention of health literacy among middle-aged and older adults. Perceived social support and self-efficacy not only have independent mediating effects but also significant chain mediating effects in the relationship between media exposure and health literacy among this population. Therefore, improving the health literacy of middle-aged and older people can be popularized through media and improved in a multi-path, all-round, and precise way with the help of related technologies and social forces from which media literacy can be improved.

A cross-sectional study: family communication, anxiety, and depression in adolescents: the mediating role of family violence and problematic internet use

OBJECTIVE

The objective of this study is to explore the relationship between family communication, family violence, problematic internet use, anxiety, and depression and validate their potential mediating role.

METHODS

The study population consisted of Chinese adolescents aged 12 to 18 years, and a cross-sectional survey was conducted in 2022. Structural equation models were constructed using AMOS 25.0 software to examine the factors that influence adolescent anxiety and depression and the mediating effects of problematic internet use and family violence.

RESULTS

The results indicate that family communication was significantly and negatively related to family violence (β = -.494, p < 0.001), problematic internet use (β = -.056, p < .05), depression (β = -.076, p < .01), and anxiety (β = -.071, p < .05). And the finds also indicate that family violence mediated the relationships between family communication and depression (β = -.143, CI: -.198 -.080), and between family communication and anxiety (β = -.141; CI: -.198 -.074). Chain indirect effects between family communication and depression (β = -.051; CI: -.081 -.030) or anxiety (β = -.046; CI: -.080 -.043) via family violence and then through problematic internet use were also found in the present study.

CONCLUSIONS

In conclusion, positive family communication is crucial in reducing anxiety and depression in adolescents. Moreover, problematic internet use and family violence mediate the effects of positive family communication on anxiety and depression. Therefore, improving family communication and promoting interventions aimed at reducing family violence and problematic internet use can help reduce anxiety and depression in adolescents, thus promoting their healthy development.

The Effect of Teacher Discrimination Behavior on Adolescent Suicidal Ideation: A Cross-Sectional Survey

Introduction

 Suicidal ideation and suicidal behavior, as the most severe psychological and behavioral problems among adolescents, bring not only significant damage to individual social functioning but also cause enormous economic and social pressure, which will ultimately be detrimental to social development and social stability. This paper aimed to explore the potential relationship between teacher discrimination behavior, peer bullying victimization, anxiety disorders, and adolescent suicidal ideation based on the Vulnerability-Stress Model.

Methods

 From September to November 2022, our research team surveyed 21,017 junior high school students from 12 secondary schools in ten cities in China. Mplus 8.3 software was used to analyze the pathways of teacher discrimination behavior on adolescent suicidal ideation.

Results

 The results showed that teacher preference had a significant negative effect on suicidal ideation, and teacher prejudice significantly positively affected suicidal ideation. Mediation test results indicated that there were significant independent mediating effects of peer bullying victimization and anxiety disorders between teacher discrimination behavior and adolescents' suicidal ideation, as well as significant chain mediating effects.

Conclusion

 Secondary school teachers should improve their self-quality and pay more attention to adolescents' suicidal ideation. Teachers are expected to put love into their education, respect and trust each student, and attend to their emotional needs unbiasedly. Educators should develop targeted prevention and intervention measures according to the actual situation of school bullying and also strengthen adolescents' life-value education to improve the psychological quality of adolescents and create a healthy campus atmosphere.

[HbA1c comparison and diagnostic efficacy analysis of multi center different glycosylated hemoglobin detection systems]

Objective: Compare and analyze the results of the domestic Lanyi AH600 glycated hemoglobin analyzer and other different detection systems to understand the comparability of the detection results of different detectors, and establish the best cut point of Lanyi AH600 determination of haemoglobin A1c (HbA1c) in the diagnosis of diabetes. Methods: Multi center cohort study was adopted. The clinical laboratory departments of 18 medical institutions independently collected test samples from their respective hospitals from March to April 2022, and independently completed comparative analysis of the evaluated instrument (Lanyi AH600) and the reference instrument HbA1c. The reference instruments include four different brands of glycosylated hemoglobin meters, including Arkray, Bio-Rad, DOSOH, and Huizhong. Scatter plot was used to calculate the correlation between the results of different detection systems, and the regression equation was calculated. The consistency analysis between the results of different detection systems was evaluated by Bland Altman method. Consistency judgment principles: (1) When the 95% limits of agreement (95% LoA) of the measurement difference was within 0.4% HbA1c and the measurement score was≥80 points, the comparison consistency was good; (2) When the measurement difference of 95% LoA exceeded 0.4% HbA1c, and the measurement score was≥80 points, the comparison consistency was relatively good; (3) The measurement score was less than 80 points, the comparison consistency was poor. The difference between the results of different detection systems was tested by paired sample T test or Wilcoxon paired sign rank sum test; The best cut-off point of diabetes was analyzed by receiver operating characteristic curve (ROC). Results: The correlation coefficient R² of results between Lanyi AH600 and the reference instrument in 16 hospitals is≥0.99; The Bland Altman consistency analysis showed that the difference of 95% LoA in Nanjing Maternity and Child Health Care Hospital in Jiangsu Province (reference instrument: Arkray HA8180) was -0.486%-0.325%, and the measurement score was 94.6 points (473/500); The difference of 95% LoA in the Tibetan Traditional Medical Hospital of TAR (reference instrument: Bio-Rad Variant II) was -0.727%-0.612%, and the measurement score was 89.8 points; The difference of 95% LoA in the People's Hospital of Chongqing Liang Jiang New Area (reference instrument: Huizhong MQ-2000PT) was -0.231%-0.461%, and the measurement score was 96.6 points; The difference of 95% LoA in the Taihe Hospital of traditional Chinese Medicine in Anhui Province (reference instrument: Huizhong MQ-2000PT) was -0.469%-0.479%, and the measurement score was 91.9 points. The other 14 hospitals, Lanyi AH600, were compared with 4 reference instrument brands, the difference of 95% LoA was less than 0.4% HbA1c, and the scores were all greater than 95 points. The results of paired sample T test or Wilcoxon paired sign rank sum test showed that there was no statistically significant difference between Lanyi AH600 and the reference instrument Arkray HA8180 (Z=1.665,P=0.096), with no statistical difference. The mean difference between the measured values of the two instruments was 0.004%. The comparison data of Lanyi AH600 and the reference instrument of all other institutions had significant differences (all P<0.001), however, it was necessary to consider whether it was within the clinical acceptable range in combination with the results of the Bland-Altman consistency analysis. The ROC curve of HbA1c detected by Lanyi AH600 in 985 patients with diabetes and 3 423 patients with non-diabetes was analyzed, the area under curve (AUC) was 0.877, the standard error was 0.007, and the 95% confidence interval 95%CI was (0.864, 0.891), which was statistically significant (P<0.001). The maximum value of Youden index was 0.634, and the corresponding HbA1c cut point was 6.235%. The sensitivity and specificity of diabetes diagnosis were 76.2% and 87.2%, respectively. Conclusion: Among the hospitals and instruments currently included in this study, among these four hospitals included Nanjing Maternity and Child Health Care Hospital in Jiangsu Province (reference instrument: Arkray HA8180), Tibetan Traditional Medical Hospital of TAR (reference instrument: Bio-Rad Variant Ⅱ), the People's Hospital of Chongqing Liang Jiang New Area (reference instrument: Huizhong MQ-2000PT), and the Taihe Hospital of traditional Chinese Medicine in Anhui Province (reference instrument: Huizhong MQ-2000PT), the comparison between Lanyi AH600 and the reference instruments showed relatively good consistency, while the other 14 hospitals involved four different brands of reference instruments: Arkray, Bio-Rad, DOSOH, and Huizhong, Lanyi AH600 had good consistency with its comparison. The best cut point of the domestic Lanyi AH600 for detecting HbA1c in the diagnosis of diabetes is 6.235%.

Research on the Cooperative Governance Path of Multiple Stakeholders in Doctor-Patient Disputes under the Environment of Information Asymmetry

The number of doctor-patient conflicts and disputes in China has been increasing recently. In order to solve the current social problems of the tense doctor-patient relationship and frequent medical disputes, this article, based on grounded theory, uses qualitative analysis software to conduct grounded coding on 622 cases of doctor-patient disputes randomly selected by stratification. After successively adopting open, axial, and selective coding, the relationship structure between the causes and development of medical disputes is summarized. Furthermore, this relationship structure can be used to analyze further and discuss the causes of doctor-patient disputes from the perspective of multiple co-governance and the governance framework of doctor-patient disputes. Finally, it reminds us of the need to standardize government's regulatory responsibilities, promote the equal distribution of medical resources, strengthen the communication awareness between doctors and patients, reduce the information asymmetry between doctors and patients, and build a preventive mechanism-oriented multi-subject collaborative governance path to promote the relationship between doctors and patients in China. We provide relevant countermeasures and suggestions for harmonious development and the smooth resolution of doctor-patient conflicts.

[The network investigation on knowledge, attitude and practice about Novel coronavirus pneumonia of the residents in Anhui Province]

Objective: To analyze the current situation of the knowledge, attitudes and practice about Novelcoronavirus pneumonia (NCP) of the residents in Anhui Province. Methods: Anonymous network sampling survey was carried out with an electronic questionnaire that designed by the questionnaire star, and a total of 4016 subjects from Anhui province were investigated. The content of the survey includes that the basic information of subjects,the residents' knowledge, attitudes and practice about NCP, as well as their satisfaction with the prevention and control measures adopted by the government and health authorities and the suggestions on future prevention. The questionnaire doesn't involve any privacy information, and all questions were mandatory to ensure the response rate. Results: The M (P(25), P(75)) age the 4016 subjects was 21 (19, 24), and the ranging from 7 to 80 years old. The number of males was1431(35.6%). Social networking tools such as WeChat and QQ were the main sources of epidemic information for residents (97.8%, 3 929 respondents). Residents have a high awareness rate of the main symptoms, transmission routes, using of masks, hand washing and treatment information of NCP, while a low awareness rate of the atypical symptoms. 92.6% of the subjects (n=3 720) think that the outbreak was scary. In terms of psychological behavior scores, the results showed that female (9.38±4.81), the urban (9.37±5.02) and the medical workers (10.79±5.19) had a poorer mental health than the male (8.45±5.00) , the rural (8.71±4.75) and the non-medical workers (the students: 8.85±4.83; public institude workers: 9.02±5.08; others: 8.97±5.39) (P < 0.05). 71.9% of the residents (n=2 887)were satisfied with the local epidemic control measures. The residents took various of the measures to prevent and control the epidemic. The ratio of residents that could achieve "no gathering and less going out" , "wear masks when going out" and "do not go to crowded and closed places" was up to 97.4% (n=3 913), 93.6% (n=3758) and 91.5% (n=3 673) respectively. Conclusion: The residents in Anhui province have a good KAP about NCP, yet it is necessary to strengthen the community publicity, the mental health maintenance of residents and students' health education.

[A clinical performance study of modified CT angiography in detecting bronchial artery-pulmonary artery fistula]

Objective: To evaluate the clinical value of modified computed tomography angiography(CTA) in detecting bronchial artery-pulmonary artery fistula(BPF). Methods: Retrospective analysis was performed on 246 patients with hemoptysis admitted to the First Affiliated Hospital of Wenzhou Medical University from July 2017 to December 2018, who underwent modified CTA and DSA examination at the same time. CT was performed with Toshiba Aquilion one 320 row 640-slice spiral CT scanner. All modified CTA images were read blindly by two radiologists above the attending doctors. The sensitivity, specificity and accuracy of the modified CTA in diagnosing BPF were calculated with the DSA results as the reference,and the consistency of the two tests was analyzed. Results: DSA detected 186 cases of positive and 60 cases of negative, modified CTA detected 160 cases of positive and 86 cases of negative. The sensitivity,specificity and accuracy of modified CTA for BPF diagnosis was 85.5%(159/186),98.3%(59/60), 88.6%(218/246) respectively, and they were with high consistency with DSA examination results (kappa=0.73,P<0.01). Conclusion: Modified CTA has high diagnostic specificity for BPF,which can be used as the preferred method for non-invasive screening of suspected BPF patients.

[Preliminary application of transjugular intrahepatic portosystemic shunt in individualized treatment of patients with cirrhotic portal hypertension complicated with refractory ascites and variceal hemorrhage]

Objective: To investigate the feasibility, efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) in the individualized treatment of patients with refractory ascites and variceal hemorrhage caused by portal hypertension. Methods: Prospective study of clinical data of 47 patients with portal hypertension and refractory ascites and variceal bleeding admitted to the Affiliated Hospital of Xuzhou Medical University from August 2017 to December 2018, 26 males and 21 females, aged 23-75 (52±14) years old. The Viabahn stent was used to control the diameter of the shunt and the preoperative interval of PPG after individualized TIPS was determined according to the preoperative liver function Child-Pugh classification. The PPG of the Child A and B patients was <10 mm Hg (1 mmHg=0.133 kPa), Child-Pugh C grade patients with postoperative PPG interval values of 12 to 15 mmHg. The success rate, hemostasis rate, ascites remission rate, and complication rate were recorded. Results: Forty-seven patients were with a success rate of 100%, and there was no surgically related fatal complications. The portal pressure gradients of patients with Child-Pugh A, B and Child-Pugh C were reduced from preoperative (22.5±5.4), (24.4±2.6) mm Hg to postoperative (8.8±2.5), (13.2±1.1) mm Hg (all P<0.05). All the patients were followed up for 6 to 24 months, with a median follow-up of 13 months. The success rate of hemostasis in patients with upper gastrointestinal bleeding was 93.5% (29/31), the remission rate of patients with refractory ascites was 14/16, the postoperative rebleeding rate was 6.5% (2/31), the incidence of hepatic encephalopathy was 8.5% (4/47), and the shunt disorder was 2.1% (1/47). Conclusion: The use of Viabahn stent for individualized TIPS in the treatment of portal hypertension with refractory ascites and variceal hemorrhage is feasible, and the clinical efficacy is affirmative, which can reduce the incidence of postoperative hepatic encephalopathy and shunt dysfunction.

Lasing mode regulation and single-mode realization in ZnO whispering gallery microcavities by the Vernier effect

The wide direct bandgap and strong exciton binding energy of ZnO have inspired examinations of ultraviolet lasing over the previous decades. However, regulation of the lasing mode, especially the realization of single mode lasing, is still a challenge. In this study, a ZnO comb-like structure with an array of microrods was selected to design coupled whispering-gallery-mode cavities, wherein the naturally varied air-gap between the adjacent microrods created a flexible condition for optical field coupling without any complicated micromanipulation. Spectral behaviour of lasing and coupling interaction between coupled ZnO microrods were systematically investigated. By regulating the nano-scale inter-space of dual coupled microrods, stable single-mode lasing with a higher Q factor and lower threshold was obtained successfully based on the Vernier effect. The formation conditions and the mechanism of single-mode lasing derived from the coupled ZnO microrods were discussed in detail. It also demonstrated an approach to construct high quality single-mode lasing by tuning the diameters of the coupled ZnO microrods.

Identification and expression analysis of YABBY family genes associated with fruit shape in tomato (Solanum lycopersicum L.)

YABBY family genes play important roles in the development of leaf, flower, and fruit. The purpose of this research was to integrate all the YABBY genes and analyze the correlation between gene expression and fruit shape in tomato. Scanning of 24 genomes of sequenced species demonstrated that YABBY genes were very normal and stable in flowering plants except the seedless plants. Nine YABBY genes in tomato were computationally and experimentally characterized. The phylogeny was constructed based on whole proteins or the YABBY domain, and five distinct clades were observed as described in other angiosperms. A comparison of the expression patterns in tomatoes with large differences in fruit shape and/or size suggested that during the fruit development, YABBY genes had both negative and positive functions. The obtained information could provide a deeper understanding of the evolution of YABBY genes and can also be useful for tomato yield and shape breeding.

High gain Ga₂O₃ solar-blind photodetectors realized via a carrier multiplication process

Ga2O3 photodetectors with interdigitated electrodes have been designed and fabricated, and the Ga2O3 area exposed to illumination acts as the active layer of the photodetector, while the area covered by Au interdigital electrode provide an arena for carrier multiplication. The photodetectors show a maximum responsivity at around 255 nm and a cutoff wavelength of 260 nm, which lies in the solar-blind region. The responsivity of the photodetector reaches 17 A/W when the bias voltage is 20 V, which corresponds to a quantum efficiency of 8228%, amongst the best value ever reported in Ga2O3 film based solar-blind photodetectors.

Studies on different iron source absorption by in situ ligated intestinal loops of broilers

The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

Ethanol hypersensitivity and olfactory discrimination defect in mice lacking a homolog of Drosophila neuralized

Neurogenic genes in the Notch receptor-mediated signaling pathway play important roles in neuronal cell fate specification as well as neuronal differentiation. The Drosophila neuralized gene is one of the neurogenic genes. We have cloned a mouse homolog of Drosophila neuralized, m-neu1, and found that the m-neu1 transcript is expressed in differentiated neurons. Mice deficient for m-neu1 are viable and morphologically normal, but exhibit specific defects in olfactory discrimination and hypersensitivity to ethanol. These findings reveal an essential role of m-neu1 in ensuring proper processing of certain information in the adult brain.

Mouse numb is an essential gene involved in cortical neurogenesis

During neurogenesis of the mammalian neocortex, neural progenitor cells divide to generate daughter cells that either become neurons or remain as progenitor cells. The mouse numb (m-numb) gene encodes a membrane-associated protein that is asymmetrically localized to the apical cell membrane of dividing cortical progenitor cells and may be segregated to only the apical daughter cell that has been suggested to remain as a progenitor cell. To examine m-numb function during neural development, we generated a loss-of-function mutant allele of m-numb. Mice homozygous for this mutation exhibit severe defects in cranial neural tube closure and precocious neuron production in the forebrain and die around embryonic day 11.5 (E11. 5). These findings suggest that m-numb is an essential gene that plays a role in promoting progenitor cell fate during cortical neurogenesis.

Miranda as a multidomain adapter linking apically localized Inscuteable and basally localized Staufen and Prospero during asymmetric cell division in Drosophila

Neuroblasts in the developing Drosophila CNS asymmetrically localize the cell fate determinants Numb and Prospero as well as prospero RNA to the basal cortex during mitosis. The localization of Prospero requires the function of inscuteable and miranda, whereas prospero RNA localization requires inscuteable and staufen function. We demonstrate that Miranda contains multiple functional domains: an amino-terminal asymmetric localization domain, which interacts with Inscuteable, a central Numb interaction domain, and a more carboxy-terminal Prospero interaction domain. We also show that Miranda and Staufen have similar subcellular localization patterns and interact in vitro. Furthermore, miranda function is required for the asymmetric localization of Staufen. Miranda localization is disrupted by the microfilament disrupting agent latrunculin A. Our results suggest that Miranda directs the basal cortical localization of multiple molecules, including Staufen and prospero RNA, in mitotic neuroblasts in an actin-dependent manner.

Differential expression of mammalian Numb, Numblike and Notch1 suggests distinct roles during mouse cortical neurogenesis

During Drosophila neurogenesis, asymmetric cell divisions are achieved by differential segregation of Numb (d-Numb) into one of the daughter cells to cause a bias in the Notch mediated cell-cell interaction. We have isolated a second mammalian gene with significant sequence similarity to d-numb, mouse numblike. When expressed in dividing neural precursors in Drosophila, Numblike is symmetrically distributed in the cytoplasm, unlike endogenous d-Numb or expressed mouse Numb (m-Numb), both of which are asymmetrically localized to one half of the cell membrane. In d-numb loss-of-function mutant embryos, expression of Numblike allows both daughter cells of a neural precursor to adopt the fate of the cell that normally inherits d-Numb. In mice, numblike mRNA is preferentially expressed in adult and embryonic nervous system. In the developing neocortex, Numblike is expressed in postmitotic neurons in the cortical plate, but not in progenitors within the ventricular zone where m-Numb and Notch1 are expressed. We have also found that, in dividing cortical progenitors, Notch1 is distributed around the entire membrane, unlike m-Numb which is asymmetrically localized to the apical membrane. We propose that an interplay between cell-intrinsic mechanisms (executed by m-numb and numblike) and cell-extrinsic mechanisms (mediated by Notch1) may be involved in both progenitor cell proliferation and neuronal differentiation during mammalian cortical neurogenesis.

Asymmetric localization of a mammalian numb homolog during mouse cortical neurogenesis

During Drosophila neurogenesis, differential segregation of Numb is necessary for daughter cells of asymmetric divisions to adopt distinct fates, at least partly by biasing the Notch-mediated cell-cell interaction. We have isolated a highly conserved mammalian homolog of Drosophila numb, m-numb. During mouse cortical neurogenesis, m-Numb is asymmetrically localized to the apical membrane of dividing ventricular neural progenitors. Depending upon the orientation of the cleavage plane, m-Numb may be distributed into one or both of the daughter cells. When expressed in Drosophila embryos, m-Numb is localized asymmetrically in dividing neural precursors and rescues the numb mutant phenotype. Furthermore, m-Numb can physically interact with mouse Notch1. We propose that some shared molecular mechanisms, both cell-intrinsic and cell-extrinsic, generate asymmetric cell divisions during neurogenesis of vertebrates and invertebrates.

Morphological properties and projections of electrophysiologically characterized neurons in the guinea-pig submucosal plexus

Intracellular recordings were made from 73 guinea-pig submucosal neurons using neurobiotin-filled microelectrodes; subsequently, neuropeptide immunoreactivity, morphology and nerve fibre projections were determined. Five distinct groups of cells could be distinguished: S cells with inhibitory input (61%), S cells without inhibitory input (19%), AH cells (8%), S-AH cells (5%), and glial networks. S cells with inhibitory input were immunoreactive for vasoactive intestinal polypeptide and showed Dogiel Type III morphology with the axon branching and coursing through two to 12 ganglia; varicosities and tufts of varicosities were observed surrounding other cell bodies as well as over blood vessels. S cells without inhibitory input primarily were immunoreactive for neuropeptide Y; they also showed Dogiel Type III morphology and similar, though shorter, axonal projections and varicose features surrounding other neurons. AH cells, which most likely contained substance P, lacked synaptic input and exhibited Dogiel Type II morphology; they branched more extensively than S cells and also formed varicose tufts within other ganglia. S-AH cells combined electrophysiological properties of S cells with inhibitory input and AH cells and did not show consistent morphological or histochemical characteristics. Typical glial networks were observed; in addition, on two occasions unusual networks of dye and electrical coupling between S cells without inhibitory input and a glial complex were observed. These results suggest that vasoactive intestinal polypeptide-containing S cells may act as interneurons which mediate a slow excitatory synaptic potential; that neuropeptide Y-containing S cells, which are known to be cholinergic, may play a role as cholinergic interneurons mediating the nicotinic fast excitatory synaptic potential; and that AH neurons also may provide cholinergic innervation to other submucosal neurons in addition to their previously described dual projections into mucosa and myenteric plexus.

Mucosal stimulation evokes vasodilation in submucosal arterioles by neuronal and nonneuronal mechanisms

The effects of mechanical stimulation of intestinal mucosa on submucosal arterioles of guinea pig ileum were examined using video microscopy of in vitro preparations consisting of submucosal plexus with adjacently attached mucosa. Mucosal stimulation did not alter the diameter of relaxed vessels but dilated arterioles preconstricted with phenylephrine or the prostaglandin analogue U-46619. Tetrodotoxin (TTX) or muscarinic receptor antagonists inhibited the vasodilation evoked by mucosal stimulation in 60% of preparations examined from normal and extrinsically denervated animals. The TTX-sensitive vasodilation to mucosa stimulation was partially inhibited by the 5-hydroxytryptamine3 (5-HT3) receptor antagonist ICS 205930. The TTX-insensitive vasodilation was largely prevented when the histamine receptor antagonists cimetidine and pyrilamine and the prostaglandin synthesis inhibitor indomethacin were applied. This study has demonstrated a reflex vasodilation to mucosal stimulation in an isolated submucosal plexus preparation that involves both neuronal and nonneuronal pathways. The neuronal pathway converges on cholinergic vasodilator neurons in the submucosal ganglia. The nonneuronal pathway involves the release of 5-HT, histamine, and prostaglandins from mucosal elements; 5-HT excites cholinergic vasodilator neurons, whereas histamine and prostaglandins dilate submucosal arterioles directly.

Cholera toxin-sensitive neurons in guinea pig submucosal plexus

Cholera toxin (CT) increases intestinal secretions by direct stimulation of mucosal enterocytes; enteric neurons also may play a role. We tested the latter possibility by retrograde labeling of mucosal terminals in guinea pig small intestine with the B subunit of CT (B-CT) and by intracellular recordings from submucosal neurons during superfusion with CT. All vasoactive intestinal peptide (VIP)-positive neurons, and only VIP-positive neurons, were labeled with B-CT. Fluorogold (FG) was used to retrogradely label nerve terminals in submucosal arterioles in preparations in which B-CT labeled mucosal terminals; colocalization of B-CT with FG was observed in neurons up to 3 mm from the site of FG application. CT selectively depolarized neurons known to contain VIP. We conclude that all VIP-containing neurons, and only VIP neurons, in guinea pig submucosal plexus possess B-CT binding sites and can be activated by CT. Some of these neurons provide a dual innervation to both arterioles and mucosa. We suggest that one functional consequence of CT may be to activate vasodilator nerves, thus increasing vascular perfusion of the mucosa to further stimulate intestinal secretions.

Re-innervation of submucosal arterioles by myenteric neurones following extrinsic denervation

We used a combination of selective lesions, immunohistochemistry and video monitoring of arteriolar diameter to determine the source of the changes in vasodilator innervation to guinea pig ileal submucosal arterioles which occur following removal of their extrinsic sympathetic and sensory nerve fibre input. A non-cholinergic neurogenic vasodilation appeared in arterioles in which extrinsic denervation was performed 50-90 days previously. The non-cholinergic innervation did not result from regrowth of extrinsic fibres because the neurogenic response was not altered by combining long-term denervation with capsaicin treatment or re-denervation 7 days prior to examination. However, non-cholinergic neurogenic vasodilations were not observed in arterioles which had been subjected to long-term denervation combined with a myectomy 7 days prior to examination. Immunohistochemical co-localization of SP and CGRP in these vessels confirmed previous findings that a prominent SP perivascular nerve plexus appeared after long-term denervation. Perivascular SP-containing fibres that appeared after long-term denervation were unaffected by capsaicin or re-denervation but were absent from preparations in which long-term denervation and myectomy were performed. These results demonstrate that myenteric neurones are the source of the non-cholinergic innervation which appears after extrinsic denervation and support our previous conclusion that SP is the neurotransmitter responsible for this non-cholinergic vasodilation in submucosal arterioles of the small intestine.

Characterization of vasopressin actions in isolated submucosal arterioles of the intestinal microcirculation

Submucosal arterioles are the final resistance vessels of the mesenteric circulation; they supply intestinal mucosa and smooth muscle and contribute significantly to total mesenteric resistance. Characterization of receptors present on submucosal arterioles has not been carried out, because these vessels have not been accessible to study by previous methods. We have used a novel optical method for on-line tracking of outside diameter from in vitro preparations of submucosal arterioles in the ileum and colon of guinea pigs, rabbits, and humans to characterize the vasoconstrictor responses to vasopressin as well as other vasopressor agents along the gastrointestinal tract. All ileal submucosal arterioles showed smoothly graded constrictor responses, whereas colonic arterioles from each species exhibited rhythmic vasoconstrictions. Vasopressin constricted guinea pig and human submucosal arterioles (EC50, 1 nM) by activating classical V1 receptors; dissociation equilibrium constants (Kd) for the V1 antagonist d(CH2)5 Tyr (Me) arginine vasopressin were 1-3 nM. This antagonist was 10-50-fold more potent in inhibiting vasopressin constrictions in rabbit submucosal arterioles (Kd = 0.05-0.1 nM). No evidence for the presence of V2 receptors was obtained in any arteriole, and no significant differences in the alpha 1-adrenoceptor-mediated constrictions were observed in these vessels. Results from this study suggest the presence of heterogeneity of V1 receptors in submucosal arterioles; these differences appear to be species dependent. Our results also suggest that intrinsic vasoconstrictor properties of submucosal arterioles differ along the length of the gastrointestinal tract; these differences appear to be species independent.

Effects of deoxycorticosterone acetate on muscle electrolytes, resting potential and mitochondria in rats

Deoxycorticosterone acetate, injected daily for 5, 10, 20 or 30 days, reduced the serum potassium levels of rats by about 25%, a decrease that was independent of the treatment period employed. Serum sodium concentrations were unchanged with treatment duration. The potassium concentrations in extensor digitorum longus (EDL) and soleus (SOL) muscles were significantly decreased, and those of sodium increased, after treatment. Accompanying these changes of electrolyte concentration, the resting membrane potentials of treated EDL and SOL were hyperpolarized in vivo, and showed depolarization with the decreases of external potassium concentrations in vitro. The mitochondria in the muscles of treated rats were damaged. The degree of damage was more serious in EDL than in SOL and was dependent on the duration of deoxycorticosterone acetate treatment.

Substance P mediates neurogenic vasodilatation in extrinsically denervated guinea-pig submucosal arterioles

1. Arteriolar diameter was measured using an optical method in preparations of guinea-pig submucosal plexus in vitro. Electrical stimulation of one or more neurones in ganglia of the submucosal plexus causes a cholinergic vasodilatation in normal animals. The vasomotor innervation to the arterioles was studied in guinea-pigs in which the extrinsic nerves to the intestine had been removed. Tissues were processed for immunohistochemistry after the in vitro experiments. 2. Extrinsic denervation resulted in complete loss of catecholamine fluorescence, NPY (neuropeptide Y) and CGRP (calcitonin gene-related peptide) immunofluorescence around the blood vessels and no neurogenic vasoconstriction was observed up to 60 days post-denervation. Vasodilatation in response to ganglionic stimulation was increased; smaller arterioles (outside diameter less than 40 microns) showed a greater enhancement of neurogenic vasodilatation than larger arterioles. 3. Nerve-evoked vasodilatations were only partially inhibited by muscarinic antagonists at 30-60 days after extrinsic denervations. 4. The non-cholinergic neurogenic vasodilatation was abolished by the substance P antagonists, spantide, [D-Arg1, D-Pro2, D-Trp7.9, Leu11]substance P and [D-Arg1, D-Phe5, D-Trp7.9, Leu11]substance P. These antagonists did not alter the cholinergic vasodilatation in normal or extrinsically denervated arterioles. 5. Exogenous substance P dilated all submucosal arterioles; the concentration which produced half-maximal vasodilatations was 2.5 mM in both normal and extrinsically denervated arterioles. Substance P antagonists inhibited the vasodilatation caused by substance P at concentrations similar to those needed to block nerve-mediated vasodilatation. 6. There was a strong correlation between the finding of non-cholinergic vasodilatation in response to ganglionic stimulation, and the presence of substance P-immunoreactive fibres running from ganglion to arteriole. This correlation did not exist for VIP (vasoactive intestinal peptide). 7. These results suggest that intrinsic intestinal substance P-containing nerve fibres supply submucosal arterioles after sympathetic efferents and sensory afferents are removed. Stimulation of these nerves releases substance P to produce arteriolar dilatation.