[Exploration and validation of optimal cut-off values for tPSA and fPSA/tPSA screening of prostate cancer at different ages]

Objective: To determine the total and age-specific cut-off values of total prostate specific antigen (tPSA) and the ratio of free PSA divided total PSA (fPSA/tPSA) for screening prostate cancer in China. Methods: Based on the Chinese Colorectal, Breast, Lung, Liver, and Stomach cancer Screening Trial (C-BLAST) and the Tianjin Common Cancer Case Cohort (TJ4C), males who were not diagnosed with any cancers at baseline since 2017 and received both tPSA and fPSA testes were selected. Based on Cox regression, the overall and age-specific (＜60, 60-＜70, and ≥70 years) accuracy and optimal cut-off values of tPSA and fPSA/tPSA ratio for screening prostate cancer were evaluated with time-dependent receiver operating characteristic curve (tdROC) and area under curve (AUC). Bootstrap resampling was used to internally validate the stability of the optimal cut-off value, and the PLCO study was used to externally validate the accuracy under different cut-off values. Results: A total of 5 180 participants were included in the study, and after a median follow-up of 1.48 years, a total of 332 prostate cancer patients were included. In the total population, the tdAUC of tPSA and fPSA/tPSA screening for prostate cancer were 0.852 and 0.748, respectively, with the optimal cut-off values of 5.08 ng/ml and 0.173, respectively. After age stratification, the age specific cut-off values of tPSA in the <60, 60-<70, and ≥70 age groups were 3.13, 4.82, and 11.54 ng/ml, respectively, while the age-specific cut-off values of fPSA/tPSA were 0.153, 0.135, and 0.130, respectively. Under the age-specific cut-off values, the sensitivities of tPSA screening for prostate cancer in males <60, 60-70, and ≥70 years old were 92.3%, 82.0%, and 77.6%, respectively, while the specificities were 84.7%, 81.3%, and 75.4%, respectively. The age-specific sensitivities of fPSA/tPSA for screening prostate cancer were 74.4%, 53.3%, and 55.9%, respectively, while the specificities were 83.8%, 83.7%, and 83.7%, respectively. Both bootstrap's internal validation and PLCO external validation provided similar results. The combination of tPSA and fPSA/tPSA could further improve the accuracy of screening. Conclusion: To improve the screening effects, it is recommended that age-specific cut-off values of tPSA and fPSA/tPSA should be used to screen for prostate cancer in the general risk population.

12-HETE activates Müller glial cells: The potential role of GPR31 and miR-29

Diabetic retinopathy (DR) is a neurovascular complication of diabetes, driven by an intricate network of cellular and molecular mechanisms. This study sought to explore the mechanisms by investigating the role of 12-hydroxyeicosatetraenoic acid (12-HETE), its receptor GPR31, and microRNA (miR-29) in the context of DR, specifically focusing on their impact on Müller glial cells. We found that 12-HETE activates Müller cells (MCs), elevates glutamate production, and induces inflammatory and oxidative responses, all of which are instrumental in DR progression. The expression of GPR31, the receptor for 12-HETE, was prominently found in the retina, especially in MCs and retinal ganglion cells, and was upregulated in diabetes. Interestingly, miR29 showed potential as a protective agent, mitigating the harmful effects of 12-HETE by attenuating inflammation and oxidative stress, and restoring the expression of pigment epithelium-derived factor (PEDF). Our results underline the central role of 12-HETE in DR progression through activation of a neurovascular toxic pathway in MCs and illuminate the protective capabilities of miR-29, highlighting both as promising therapeutic targets for the management of DR.

[A historical review of dental schools founded by dentist Situ Bo in modern time]

About 8 dental schools were founded by Chinese dentists during modern times (1909-1949) in China. Only one still worked after the founding of the People's Republic of China, which was one of the three dental schools founded by dentist Situ Bo. There were no systematic researches on Situ Bo's participation in dentistry education. This paper analyzes the founder's experience in dentistry and in the two schools he founded at the beginning, focusing on the background and process of the schools' construction, management, teaching, teachers and students training, etc. The results show that the establishment of the first two dental schools have laid important foundation for the establishment and development of Shanghai Dental College by the reserve of trained professional teachers and accumulated valuable experience in running schools. The systematic review of this history will help us better understand the establishment and development of Shanghai Dental College and the efforts in dentistry education made by dentists growed up in modern China, as well as the early development process of stomatology.

[Formation of professor Mao Xiejun's thoughts on stomatological education]

Professor Mao Xiejun wrote a report about dental education of China in 1935. From 1948 to 1950, he published three articles containing the educational idea of "developing dentistry into stomatology". When he served as the director of the Faculty of Dentistry of Peking University Medical School in July 1950, he proposed to rename the Faculty of Dentistry into the Faculty of Stomatology,which were approved by the Ministry of Health and the Ministry of Education of the People's Republic of China in one month. The Chinese Medical Association established the Society of Stomatology the next year. Later, dentistry was successively changed into stomatology, and medical content was integrated into dental education, which was of great significance and far-reaching influence. During the developments of the thought of stomatological education in China, Professor Mao Xiejun evidently played a pivotal role. In this paper, the formation process of the thoughts of stomatological education related to professor Mao Xiejun's contribution is elucidated through studying the archives, personal letters, and historical documents, so as to enrich the researches on the history of stomatology in China and to facilitate better understanding and promoting the development of stomatology.

[A historical review of dental schools founded by dentists in modern China]

Eight dental schools were founded by Chinese dentists during modern times (1909-1949) in China, but only one of them still works. This article analyzes the establishment processes, faculty and student trainings in some of these dental schools, combining with the social background and management system at that time, to explore the difficulties encountered by Chinese dentists in founding dental schools before 1949.

[A historical review of dental education and practice qualification in modern China]

A series of regulations and policies for Dental Practitioner Qualification were issued during modern times (1906-1949) in China from local to national levels, in which the certification for qualification had been largely based on dental education and training experiences. The present article reviews the evolution and progression of dental practitioner qualification management, as well as its relationship to dental education before 1949, which may hopefully provide a historical background for the development of modern dentistry and enhance the understanding of the current management process for dental practitioner qualifications in China.

[Energy metabolism characteristic with risk of secondary bacterial infection in patients with hepatitis B virus-related chronic liver disease]

Objective: To investigate and analyze the energy metabolism characteristics and the correlation between energy metabolism and the risk of secondary bacterial infection in patients with hepatitis B virus-related chronic liver disease (HBV-CLD). Methods: Data of 183 cases admitted to the Mengchao Hepatobiliary Hospital of Fujian Medical University from November 2017 to November 2020 were retrospectively analyzed. 79 cases of chronic hepatitis B, 51 cases of hepatitis B-related liver cirrhosis, and 53 cases of hepatitis B-related liver failure were collected. Among them patients with liver failure and decompensated liver cirrhosis were defined as severe liver disease group. The Quark RMR indirect calorimetry (COSMED Corporation, Italy) was used to exam the patients' energy metabolism condition, and the incidences of secondary bacterial infection of the patients during hospitalization were recorded. Shapiro-Wilk test and normal QQ plot were used to analyze the normal distribution of continuous variable data, which was consistent with the normal distribution and was described by mean ± standard deviation. In addition, if it did not conform to the normal distribution, the median and interquartile distance were used to describe it. Levene's test was used to test the homogeneity of variance of the data, which was consistent with the normal distribution. The t-test was used to compare the means of the two groups of samples. One-way analysis of variance was used to compare the mean values of the three groups of samples, and then the Tukey's test was used to compare the two groups. If the variance was uneven or did not conform to the normal distribution, the Wilcoxon rank sum test was used to compare the differences between the two groups. Kruskal-Wallis test (H test) was used to compare the differences between the three groups of samples, and then the Dunnett's test (Z test) was used for comparison between the two groups. Categorical variable data were analyzed using chi-square test. Logistic regression analysis was used to screen independent risk factors, and the criteria for variable inclusion (P < 0.05). Results: The respiratory entropy (RQ) and non-protein respiratory entropy (npRQ) of the three groups had statistically significant difference (P < 0.05). Among them, the RQ and npRQ of the chronic hepatitis B group were higher than hepatitis B-related liver cirrhosis group and hepatitis B-related liver failure group. There were statistically significant differences in fat oxidation rate (FAT%) and carbohydrate oxidation rate (CHO%) between the three groups (P < 0.05). Compared with hepatitis B-related liver cirrhosis group and hepatitis B-related liver failure group, chronic hepatitis B group (P < 0.05) had lower FAT% and higher CHO%. There were no statistically significant differences in the measured and predicted resting energy expenditure and protein oxidation rate (PRO%) between the three groups. The incidence of secondary bacterial infection in patients with severe liver disease was 48.39% (45/93). Compared with the non-infected group, the RQ and npRQ values ​​of the infected group were significantly decreased (P < 0.05), while FAT% was significantly increased (P < 0.05). Logistic regression analysis showed that glutamyltransferase, cholesterol, and npRQ were independent risk factors for secondary bacterial infections in patients with severe liver disease. Glutamyltransferase elevation, and cholesterol and npRQ depletion had suggested an increased risk of secondary bacterial infection. Subgroup analysis of patients with hepatitis B-related liver failure also showed that compared with non-infected group, RQ value and npRQ value of secondary bacterial infection group were significantly decreased (P < 0.05), while FAT% was significantly increased (P < 0.05). Conclusion: Patients with hepatitis B virus-related chronic liver disease generally have abnormal energy metabolism. Low RQ, npRQ, CHO% and high FAT% are related to the severity of the disease; while npRQ reduction is related to the risk of secondary bacterial infection in patients with severe liver disease, and thus can be used as a clinical prognostic indicator.

Immunostaining of Whole-Mount Retinas with the CLARITY Tissue Clearing Method

The tissue hydrogel delipidation method (CLARITY), originally developed by the Deisseroth laboratory, has been modified and widely used for immunostaining and imaging of thick brain samples. However, this advanced technology has not yet been used for whole-mount retinas. Although the retina is partially transparent, its thickness of approximately 200 µm (in mice) still limits the penetration of antibodies into the deep tissue as well as reducing light penetration for high-resolution imaging. Here, we adapted the CLARITY method for whole-mount mouse retinas by polymerizing them with an acrylamide monomer to form a nanoporous hydrogel and then clearing them in sodium dodecyl sulfate to minimize protein loss and avoid tissue damage. CLARITY-processed retinas were immunostained with antibodies for retinal neurons, glial cells, and synaptic proteins, mounted in a refractive index matching solution, and imaged. Our data demonstrate that CLARITY can improve the quality of standard immunohistochemical staining and imaging for retinal neurons and glial cells in whole-mount preparation. For instance, 3D resolution of fine axon-like and dendritic structures of dopaminergic amacrine cells were much improved by CLARITY. Compared to non-processed whole-mount retinas, CLARITY can reveal immunostaining for synaptic proteins such as postsynaptic density protein 95. Our results show that CLARITY renders the retina more optically transparent after the removal of lipids and preserves fine structures of retinal neurons and their proteins, which can be routinely used for obtaining high-resolution imaging of retinal neurons and their subcellular structures in whole-mount preparation.

Spontaneous Depolarization-Induced Action Potentials of ON-Starburst Amacrine Cells during Cholinergic and Glutamatergic Retinal Waves

Correlated spontaneous activity in the developing retina (termed “retinal waves”) plays an instructive role in refining neural circuits of the visual system. Depolarizing (ON) and hyperpolarizing (OFF) starburst amacrine cells (SACs) initiate and propagate cholinergic retinal waves. Where cholinergic retinal waves stop, SACs are thought to be driven by glutamatergic retinal waves initiated by ON-bipolar cells. However, the properties and function of cholinergic and glutamatergic waves in ON- and OFF-SACs still remain poorly understood. In the present work, we performed whole-cell patch-clamp recordings and Ca²⁺ imaging from genetically labeled ON- and OFF-SACs in mouse flat-mount retinas. We found that both SAC subtypes exhibited spontaneous rhythmic depolarization during cholinergic and glutamatergic waves. Interestingly, ON-SACs had wave-induced action potentials (APs) in an age-dependent manner, but OFF-SACs did not. Simultaneous Ca²⁺ imaging and patch-clamp recordings demonstrated that, during a cholinergic wave, APs of an ON-SAC appeared to promote the dendritic release of acetylcholine onto neighboring ON- and OFF-SACs, which enhances their Ca²⁺ transients. These results advance the understanding of the cellular mechanisms underlying correlated spontaneous activity in the developing retina.

[Analysis on features and functions of professional journals of stomatology published in modern China]

The professional journals of stomatology, which were dedicated to spread of theoretical knowledge and medical practices, has demonstrated their important value for studying the development of stomatology. The historical details of these stomatological journals published in modern China from 1840 to 1949, such as publication background, chief founders, aims, main features and the contents of articles, are of great importance for investigating not only the humanistic features, but also the development of stomatology in China. Twenty-three professional journals of stomatology in modern China and 2 260 articles published in them have been verified through text analysis and archives. The features and functions of these journals were further analyzed in order to enrich the humanities and historical research of modern Chinese stomatology.

Adsorption of perfluoroalkyl and polyfluoroalkyl substances (PFASs) from aqueous solution - A review

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have gained increasingly global attention in recent years. Due to their unique amphiphilic properties and stability, PFASs are recognized as highly persistent, toxic, and environmentally bioaccumulative. Among several physicochemical technologies, adsorption has been extensively used and proved to be an effective method for removing PFASs from aqueous environment. In this review article, the technical feasibility of the use of different adsorbents, such as activated carbon, ion exchange resins, minerals, molecularly imprinted polymer (MIP), carbon nanotubes (CNTs), and a wide range of potentially low-cost biosorbents, for PFASs removal from water or wastewater is critically reviewed. The evaluation and comparison of their PFASs sorption behavior in terms of kinetics and isotherms is presented. The mechanisms involved in PFASs adsorption processes, such as diffusion, electrostatic interaction, hydrophobic interaction, ion exchange and hydrogen bond, are discussed. The effects of the parameters variability on sorption process are highlighted. Based on the literature reviewed, a few recommendations for future research on PFASs adsorption are also elaborated. Capsule: The adsorption behavior and mechanisms of perfluoroalkyl and polyfluoroalkyl substances (PFASs) on various adsorbents are reviewed.

Expression of GluA2-containing calcium-impermeable AMPA receptors on dopaminergic amacrine cells in the mouse retina

Purpose

The neuromodulator dopamine plays an important role in light adaptation for the visual system. Light can stimulate dopamine release from dopaminergic amacrine cells (DACs) by activating three classes of photosensitive retinal cells: rods, cones, and melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). However, the synaptic mechanisms by which these photoreceptors excite DACs remain poorly understood. Our previous work demonstrated that α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors contribute to light regulation of DAC activity. AMPA receptors are classified into Ca2+-permeable and Ca2+-impermeable subtypes. We sought to identify which subtype of AMPA receptors is involved in light regulation of DAC activity.

Methods

AMPA receptor-mediated light responses and miniature excitatory postsynaptic currents were recorded from genetically labeled DACs in mouse retinas with the whole-cell voltage-clamp mode. Immunostaining with antibodies against tyrosine hydroxylase, GluA2 (GluR2), and PSD-95 was performed in vertical retinal slices.

Results

The biophysical and pharmacological data showed that only Ca2+-impermeable AMPA receptors contribute to DAC light responses driven by ipRGCs or cones (via depolarizing bipolar cells). We further found that the same subtype of AMPA receptors mediates miniature excitatory postsynaptic currents of DACs. These findings are supported by the immunohistochemical results demonstrating that DACs express the PSD-95 with GluA2, a subunit that is essential for determining the impermeability of AMPA receptors to calcium.

Conclusions

The results indicated that GluA2-containing Ca2+-impermeable AMPA receptors contribute to signal transmission from photosensitive retinal cells to DACs.

Transcription factor E2F1 positively regulates interferon regulatory factor 5 expression in non-small cell lung cancer

Purpose

Lung cancer is the most common malignant tumor in the world, and its incidence and mortality are very high. This study focuses on the mechanism of non-small cell lung cancer to find new therapeutic targets.

Methods

We used RT-PCR and Western blot to verify the linear relationship between E2F1 and IRF5 in normal lung tissue and lung cancer tissues. Secondly, we used overexpression and knock down E2F1 in cell lines to detect the expression of IRF5. The prime enzyme reporter plasmid verified that E2F1 binds to the core promoter region of IRF5; finally, CHIP experiments demonstrated that E2F1 binds directly to IRF5.

Results

We verified that E2F1 and IRF5 are decreased in patient tissues, and there is a strong linear relationship between E2F1 and IRF5. Secondly, we used overexpression of E2F1 or E2F1 siRNA transfected into HCC827 cells and found that E2F1 positively regulates the activity of the IRF5 promoter and the mRNA level of IRF5. Finally, the results of a chromatin immunoprecipitation assay demonstrated that E2F1 bound to the promoter region of IRF5 in vitro. These results suggested that the E2F1 transcription factor is the primary determinant for activating the basal transcription of the IRF5.

Conclusion

The transcription factor E2F1 positively regulates IRF5 in non-small cell lung cancer.

miR-939-5p decreases the enrichment of RNA polymerase II in the promoter region of CD2AP involved in nephrotic syndrome

The expression changes of CD2-associated protein (CD2AP) can lead to kidney diseases with proteinuria, including nephrotic syndrome (NS). A recent study reported that miRNAs may be important transcriptional regulators. In this study, we found increased expression of miR-939-5p and decreased expression of CD2AP in the peripheral blood of patients with NS. However, miR-939-5p did not show a regulatory effect on the 3'-untranslated region of CD2AP. The expression levels of specific protein 1 and adenovirus E2 promoter-binding factor 1, important transcription regulators in the promoter region of CD2AP, were also not affected by microRNA (miR)-939-5p. We confirmed that miR-939-5p is in the nucleus by fluorescent in situ hybridization and cytoplasmic separation polymerase chain reaction. The promoter plasmid and miR-939-5p were cotransfected into HEK-293 cells, and the luciferase reporter gene assay was used to analyze the promoter activity. We found that miR-939-5p binds to a specific sequence in the CD2AP promoter. miR-939-5p was confirmed to reduce the recruitment of RNA polymerase II to the CD2AP promoter region by chromatin immunoprecipitation. These findings improve our understanding of the mechanism of miR-939-5p in NS and provide potential molecular therapeutic targets for NS.

[Plasma relative abundance of epidermal growth factor receptor mutations predicts clinical response to epidermal growth factor receptor-tyrosine kinase inhibitors in patients with advanced lung adenocarcinoma]

Objective: To determine whether relative abundance of epidermal growth factor receptor (EGFR) mutations in plasma predicts clinical response to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced lung adenocarcinoma. Methods: In this prospective study, adult patients with advanced lung adenocarcinoma were enrolled in our hospital from 1 April 2016 to 1 January 2017. EGFR mutations in tumor tissues were detected by ADx-amplification refractory mutation system (ADx-ARMS). EGFR mutations of plasma free tumor DNA were detected by ADx-ARMS and ADx-super amplification refractory mutation system (ADx-SuperARMS) at the same time. Patients with EGFR-mutant in tumor tissues and receiving EGFR-TKIs were finally enrolled. Plasma mutation-positive patients with both methods were high abundance group.Patients with positive mutations by ADx-SuperARMS but negative by ADx-ARMS were medium abundance group. Mutation-negative patients with both methods were recognized as low abundance group. The correlation between EGFR mutation abundance and clinical response to EGFR-TKIs were analyzed. Results: Among 71 patients enrolled, 42 harbored EGFR mutations in plasma were detected by ADx-ARMS, while 53 were found by ADx-SuperARMS.There were 42 patients in high abundance group, 11 in medium group while the other 18 in low group. The objective response rates (ORRs) were 69.0%, 7/11 and 10/18 in high, medium and low groups, respectively. The difference was significant between high and low abundances groups (P=0.006). Median progression-free survival (PFS) in high, medium and low groups were 11.0, 8.5 and 9.0 monthes, respectively (P<0.001). In patients with tumor 19-Del, the ORRs were 70.4%, 5/7 and 6/11 in high, medium and low abundance groups, respectively. The median PFS of high abundance group was significantly longer than the other two groups (12.0 monthes vs 9.0, 9.0 monthes). As to subjects with L858R mutation, the ORRs were 10/15, 2/4 and 3/6, respectively, with median PFS 9.6, 5.5 and 9.5 monthes. Conclusions: The relative abundance of EGFR mutations in plasma predicts clinical response to EGFR-TKIs in patients with advanced lung adenocarcinoma. The higher the mutation abundance is, the better the efficacy of EGFR-TKIs is.

[Comparison of two serological methods in screening gastric cancer and its precancerous condition]

Objective: To compare the diagnostic value of the old "ABC" method [serum pepsinogen(PG) combined with Helicobacter pylori (Hp) IgG antibody] and the new "ABC" method [serum pepsinogen plus gastrin-17(G-17)] in screening gastric cancer and its precancerous condition. Methods: Serum PG, G-17 and Hp-IgG were quantified by enzyme-linked immunosorbent assay (ELISA) in 278 subjects. Subjects were grouped according to the criteria of two methods. The gastroscopy and pathological biopsy were gold standard. Results: The positive rate of old "ABC" method was 74.46% (207/278), which was 54.68% of new "ABC" method (151/278). For the diagnosis of gastric cancer, the sensitivity and specificity of the old "ABC" method were 90.74% and 29.46% respectively, with diagnostic coincidence rate 41.37%. The sensitivity and specificity of the new "ABC" method were 92.59% and 54.46% respectively, with diagnostic coincidence rate 61.87%. As to the diagnosis of pre-cancerous state, the sensitivity and specificity of the old "ABC" method were 75.81% and 36.00%, with diagnostic coincidence rate 58.03%. The sensitivity and specificity of the new "ABC" method were 62.10% and 75.00%, with diagnostic coincidence rate 67.86%. Conclusions: Compared with the old "ABC" method, the new "ABC" method has higher sensitivity, specificity and diagnostic coincidence rate for the diagnosis of gastric cancer, yet higher specificity and lower sensitivity for the diagnosis of precancerous conditions.

STING positively regulates human ORMDL3 expression through TBK1-IRF3-STAT6 complex mediation

Orosomucoid 1-like protein 3 (ORMDL3) is an asthma candidate gene associated with virus-triggered recurrent wheeze. Stimulator of interferon gene (STING) controls TLR-independent cytosolic responses to viruses. However, the association of STING with ORMDL3 is unclear. Here, we have shown that ORMDL3 expression shows a linear correlation with STING in recurrent wheeze patients. In elucidating the molecular mechanisms of the ORMDL3-STING relationship, we found that STING promoted the transcriptional activity of ORMDL3, which was significantly associated with increased levels of interferon regulatory factor 3 (IRF3) and signal transducer and activator of transcription 6 (STAT6). Further study showed that via activation of TANK binding kinase 1 (TBK1), STING enhanced the phosphorylation and binding of IRF3 and STAT6, which upregulated ORMDL3 by binding to the promoter. Our results showed that STING positively regulated ORMDL3 through the TBK1-IRF3-STAT6 complex.

[Diagnostic performance of T-SPOT.TB on peripheral blood in combination with adenosine deaminase on pleural fluid for the diagnosis of tuberculous pleurisy within different age group]

Objective: To evaluate the performance of T cell enzyme-linked immuno-spot assay (T-SPOT) on peripheral blood in combination with adenosine deaminase (ADA) on pleural fluid for diagnosis of tuberculous (TB) pleurisy within different age groups. Methods: The data of patients with pleural effusion from the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from April 2012 to November 2016 were retrospectively analyzed, and the diagnoses of these patients were histopathologically confirmed through medical thoracoscopy. The cases who had confirmed diagnosis, in the same time, received peripheral blood T-SPOT.TB were enrolled. The performance of peripheral blood T-SPOT.TB in combination with pleural fluid ADA on diagnosing TB pleurisy in the younger patients (16-59 years old) and elderly patients (≥60 years old) were analyzed respectively. The sensitivity, specificity and the receiver operating characteristic (ROC) curve were adopted for statistical analysis. Results: A total of 448 cases were finally enrolled, 341(76.1%) confirmed with TB pleurisy, 224 males, 117 females, (47±19) years old; and 107 (23.9%) classified as non-TB pleurisy, 65 males, 42 females, (61±14) years old. There were 285 cases who were classified as younger group, and the other 163 cases were classified as elderly group. The sensitivity and specificity of peripheral blood T-SPOT.TB were 85.4% (204/239) and 71.7% (33/46) in the younger patients, 76.5% (78/102) and 59.0% (36/61) respectively in the elderly patients. The sensitivity of peripheral blood T-SPOT.TB in the younger patients was significantly higher than that in the elderly patients (P=0.047). The sensitivity and specificity were 99.2% and 95.7% in combination with peripheral blood T-SPOT.TB and pleural fluid ADA respectively in the younger patients. The area under ROC curve (AUC) of T-SPOT.TB in the younger patients was 0.833, AUC of T-SPOT.TB combined with ADA was 0.911. The combination test of 2 tests had the sensitivity of 96.1% and the specificity of 90.2% respectively in the elderly patients. The AUC of T-SPOT.TB in the elderly patients was 0.747, AUC of T-SPOT.TB combined with ADA was 0.911. Conclusion: Peripheral blood T-SPOT.TB combined with pleural fluid ADA can improve the diagnostic performance for TB pleurisy with different ages, especially for elderly patients who can't tolerate pleural biopsy.

[Management of laryngeal stenosis after laryngeal cancer surgery]

Objective:To evaluate the surgical methods and outcomes of laryngeal stenosis after laryngeal cancer surgery. Method:Nineteen patients with laryngeal stenosis caused by partial laryngectomy were retrospectively analyzed.Two cases were treated by endoscopic laser resection. Seventeen were treated by open surgery. Among them 15 used the sternohyoid myocutaneous flap and 1 thyroid alar cartilage and 1 hyoid bone as grafts. Result:Sixteen patients were decannulated and the overall decannulation rate was 84%. A silicone T tube was remained in place from 3 to 18 months, mean 10 months. Follow-up was obtained from 11 months to 8 years. Conclusion:Vertical partial laryngectomy easily lead to laryngeal stenosis. The sternohyoid myocutaneous flap is the major approach for laryngeal stenosis. Endoscopic laser resection is effective for mild stenosis.

NMDA Receptors Contribute to Retrograde Synaptic Transmission from Ganglion Cell Photoreceptors to Dopaminergic Amacrine Cells

Recently, a line of evidence has demonstrated that the vertebrate retina possesses a novel retrograde signaling pathway. In this pathway, phototransduction is initiated by the photopigment melanopsin, which is expressed in a small population of retinal ganglion cells. These ganglion cell photoreceptors then signal to dopaminergic amacrine cells (DACs) through glutamatergic synapses, influencing visual light adaptation. We have previously demonstrated that in Mg²⁺-containing solution, α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors mediate this glutamatergic transmission. Here, we demonstrate that removing extracellular Mg²⁺ enhances melanopsin-based DAC light responses at membrane potentials more negative than −40 mV. Melanopsin-based responses in Mg²⁺-free solution were profoundly suppressed by the selective N-methyl-D-aspartate (NMDA) receptor antagonist D-AP5. In addition, application of NMDA to the retina produced excitatory inward currents in DACs. These data strongly suggest that DACs express functional NMDA receptors. We further found that in the presence of Mg²⁺, D-AP5 reduced the peak amplitude of melanopsin-based DAC responses by ~70% when the cells were held at their resting membrane potential (−50 mV), indicating that NMDA receptors are likely to contribute to retrograde signal transmission to DACs under physiological conditions. Moreover, our data show that melanopsin-based NMDA-receptor-mediated responses in DACs are suppressed by antagonists specific to either the NR2A or NR2B receptor subtype. Immunohistochemical results show that NR2A and NR2B subunits are expressed on DAC somata and processes. These results suggest that DACs express functional NMDA receptors containing both NR2A and NR2B subunits. Collectively, our data reveal that, along with AMPA receptors, NR2A- and NR2B-containing NMDA receptors mediate retrograde signal transmission from ganglion cell photoreceptors to DACs.

Orexin-A Suppresses Signal Transmission to Dopaminergic Amacrine Cells From Outer and Inner Retinal Photoreceptors

Purpose

The neuropeptides orexin-A and orexin-B are widely expressed in the vertebrate retina; however, their role in visual function is unclear. This study investigates whether and how orexins modulate signal transmission to dopaminergic amacrine cells (DACs) from both outer retinal photoreceptors (rods and cones) and inner retinal photoreceptors (melanopsin-expressing intrinsically photosensitive retinal ganglion cells [ipRGCs]).

Methods

A whole-cell voltage-clamp technique was used to record light-induced responses from genetically labeled DACs in flat-mount mouse retinas. Rod and cone signaling to DACs was confirmed pharmacologically (in wild-type retinas), whereas retrograde melanopsin signaling to DACs was isolated either pharmacologically (in wild-type retinas) or by genetic deletion of rod and cone function (in transgenic mice).

Results

Orexin-A attenuated rod/cone-mediated light responses in the majority of DACs and inhibited all DACs that exhibited melanopsin-based light responses, suggesting that exogenous orexin suppresses signal transmission from rods, cones, and ipRGCs to DACs. In addition, orexin receptor 1 antagonist SB334867 and orexin receptor 2 antagonist TCS OX229 enhanced melanopsin-based DAC responses, indicating that endogenous orexins inhibit signal transmission from ipRGCs to DACs. We further found that orexin-A inhibits melanopsin-based DAC responses via orexin receptors on DACs, whereas orexin-A may modulate signal transmission from rods and cones to DACs through activation of orexin receptors on DACs and their upstream neurons.

Conclusions

Our results suggest that orexins could influence visual function via the dopaminergic system in the mammalian retina.

Mapping physiological inputs from multiple photoreceptor systems to dopaminergic amacrine cells in the mouse retina

In the vertebrate retina, dopamine is synthesized and released by a specialized type of amacrine cell, the dopaminergic amacrine cell (DAC). DAC activity is stimulated by rods, cones, and melanopsin-expressing intrinsically photosensitive retinal ganglion cells upon illumination. However, the relative contributions of these three photoreceptor systems to the DAC light-induced response are unknown. Here we found that rods excite dark-adapted DACs across a wide range of stimulation intensities, primarily through connexin-36-dependent rod pathways. Similar rod-driven responses were observed in both ventral and dorsal DACs. We further found that in the dorsal retina, M-cones and melanopsin contribute to dark-adapted DAC responses with a similar threshold intensity. In the ventral retina, however, the threshold intensity for M-cone-driven responses was two log units greater than that observed in dorsal DACs, and melanopsin-driven responses were almost undetectable. We also examined the DAC response to prolonged adapting light and found such responses to be mediated by rods under dim lighting conditions, rods/M-cones/melanopsin under intermediate lighting conditions, and cones and melanopsin under bright lighting conditions. Our results elucidate the relative contributions of the three photoreceptor systems to DACs under different lighting conditions, furthering our understanding of the role these cells play in the visual system.

[Clinical significance of serum resistin in patients with generalized myasthenia gravis]

Objective: To detect the serum resistin levels in patients with generalized myasthenia gravis (GMG) and evaluate the clinical values of resistin. Methods: We detected the serum resistin levels in 58 patients with GMG and 58 healthy controls (HC) from January 2013 to December 2015 in Tianjin medical university general hospital.Then we analyzed the correlation of the serum resistin levels with the clinical features. Results: The serum resistin levels in patients with GMG, (8.26±4.27) ng/ml, was significantly higher than in HC, (4.12±1.36) ng/ml, (P<0.001). There was no statistical difference of the serum resistin levels between female or male patients with GMG (P=0.589). The serum resistin levels in patients with GMG was positively correlated with the quantitative MG score for disease severity (QMG) (r=0.446, P<0.001), but not correlated with age (r=0.168, P=0.206). The patients with higher resistin levels took higher risk of combining with thymoma (P=0.002), 56.5%, and these patients had higher QMG, 11(5) (P=0.001); and the ratio and QMG in the patients with lower resistin levels were 17.1%, 7(5), respectively.The GMG patients with thymoma (TGMG+ ) had remarkably higher serum resistin levels, (10.7±5.3) ng/ml (P=0.010) and the QMG score, 11(5) (P<0.001) than the GMG patients without thymoma (TGMG-) with (7.0±3.1) ng/ml and 8(5). Conclusion: Resistin is probably associated with the severity of the disease of MG, and maybe a potential biomarker of MG combined with thymoma.

Vulnerability of Dopaminergic Amacrine Cells to Chronic Ischemia in a Mouse Model of Oxygen-Induced Retinopathy

Purpose

Retinal dopamine deficiency is a potential cause of myopia and visual deficits in retinopathy of prematurity (ROP). We investigated the cellular mechanisms responsible for lowered levels of retinal dopamine in an oxygen-induced retinopathy (OIR) mouse model of ROP.

Methods

Retinopathy was induced by exposing mice to 75% oxygen from postnatal day 7 (P7) to P12. Oxygen-induced retinopathy and age-matched control mice were euthanized at P12, P17, P25, or P42 to P50. Immunohistochemistry, electrophysiology, and biochemical approaches were used to determine the effect of OIR on the structure and function of dopaminergic amacrine cells (DACs).

Results

The total number of DACs was unchanged in OIR retinas at P12 despite significant capillary dropout in the central retina. However, a significant loss of DACs was observed in P17 OIR retinas (in which neovascularization was maximal), with the cell loss being more profound in the central (avascular) than in the peripheral (neovascular) regions. Cell loss was persistent in both regions at P25, at which time retinal neovascularization had regressed. At P42, the percentage of DACs lost (54%) was comparable to the percent decrease in total dopamine content (53%). Additionally, it was found that DACs recorded in OIR retinas at P42 to P50 had a complete dendritic field and exhibited relatively normal spontaneous and light-induced electrical activity.

Conclusions

The results suggest that remaining DACs are structurally and functionally intact and that loss of DACs is primarily responsible for the decreased levels of retinal dopamine observed after OIR.

Multiple cone pathways are involved in photic regulation of retinal dopamine

Dopamine is a key neurotransmitter in the retina and plays a central role in the light adaptive processes of the visual system. The sole source of retinal dopamine is dopaminergic amacrine cells (DACs). We and others have previously demonstrated that DACs are activated by rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) upon illumination. However, it is still not clear how each class of photosensitive cells generates light responses in DACs. We genetically isolated cone function in mice to specifically examine the cone-mediated responses of DACs and their neural pathways. In addition to the reported excitatory input to DACs from light-increment (ON) bipolar cells, we found that cones alternatively signal to DACs via a retrograde signalling pathway from ipRGCs. Cones also produce ON and light-decrement (OFF) inhibitory responses in DACs, which are mediated by other amacrine cells, likely driven by type 1 and type 2/3a OFF bipolar cells, respectively. Dye injections indicated that DACs had similar morphological profiles with or without ON/OFF inhibition. Our data demonstrate that cones utilize specific parallel excitatory and inhibitory circuits to modulate DAC activity and efficiently regulate dopamine release and the light-adaptive state of the retina.

Hyperactivity of ON-type retinal ganglion cells in streptozotocin-induced diabetic mice

Impairment of visual function has been detected in the early stage of diabetes but the underlying neural mechanisms involved are largely unknown. Morphological and functional alterations of retinal ganglion cells, the final output neurons of the vertebrate retina, are thought to be the major cause of visual defects in diabetes but direct evidence to support this notion is limited. In this study we investigated functional changes of retinal ganglion cells in a type 1-like diabetic mouse model. Our results demonstrated that the spontaneous spiking activity of ON-type retinal ganglion cells was increased in streptozotocin-diabetic mice after 3 to 4 months of diabetes. At this stage of diabetes, no apoptotic signals or cell loss were detected in the ganglion cell layer of the retina, suggesting that the functional alterations in ganglion cells occur prior to massive ganglion cell apoptosis. Furthermore, we found that the increased activity of ON-type ganglion cells was mainly a result of reduced inhibitory signaling to the cells in diabetes. This novel mechanism provides insight into how visual function is impaired in diabetic retinopathy.

Functional integrity and modification of retinal dopaminergic neurons in the rd1 mutant mouse: roles of melanopsin and GABA

The progressive loss of rod and cone photoreceptors in human subjects with retinitis pigmentosa causes a gradual decline in vision and can result in blindness. Current treatment strategies for the disease rely on the integrity of inner retinal neurons, such as amacrine cells, that are postsynaptic to photoreceptors. Previous work has demonstrated that a specialized subclass of retinal amacrine cell that synthesizes and releases the key neurotransmitter dopamine remains morphologically intact during the disease; however, the pathophysiological function of these neurons remains poorly understood. Here we examined spontaneous and light-evoked spike activity of genetically labeled dopamine neurons from the retinas of retinal degeneration 1 (rd1) mice. Our results indicated that rd1 dopamine neurons remained functionally intact with preserved spontaneous spiking activity and light-evoked responses. The light responses were mediated exclusively by melanopsin phototransduction, not by surviving cones. Our data also suggested that dopamine neurons were altered during photoreceptor loss, as evidenced by less spontaneous bursting activity and increased light-evoked responses with age. Further evidence showed that these alterations were attributed to enhanced GABA/melanopsin signaling to dopamine neurons during disease progression. Taken together, our studies provide valuable information regarding the preservation and functional modification of the retinal dopamine neuronal system in rd1; this information should be considered when designing treatment strategies for retinitis pigmentosa.

Physiological and molecular characterization of connexin hemichannels in zebrafish retinal horizontal cells

Connexin channels mediate electrical synaptic transmission when assembled as cell-to-cell pores at gap junctions and can mediate transmembrane currents when expressed in plasma membranes as hemichannels. They are widely expressed in the vertebrate retina where in electrical synapses they are critical for transmission of visual signals. While the roles of connexins in electrical synapses are well-studied, the function and roles of connexin hemichannels in the nervous system are less well understood. Genetic deletion in zebrafish of connexin (Cx) 55.5 alters horizontal cell feedback to cones, spectral responses, and visual behavior. Here, we have characterized the properties of hemichannel currents in zebrafish retinal horizontal cells and examined the roles of two connexin isoforms, Cx55.5 and Cx52.6, that are coexpressed in these cells. We report that zebrafish horizontal cells express hemichannel currents that conduct inward current at physiological negative potentials and Ca(2+) levels. Manipulation of Cx55.5 and Cx52.6 gene expression in horizontal cells of adult zebrafish revealed that both Cx55.5 and Cx52.6 contribute to hemichannel currents; however, Cx55.5 expression is necessary for high-amplitude currents. Similarly, coexpression of Cx55.5 with Cx52.6 in oocytes increased hemichannel currents in a supra-additive manner. Taken together these results demonstrate that zebrafish horizontal cell hemichannel currents exhibit the functional characteristics necessary to contribute to synaptic feedback at the first visual synapse, that both Cx55.5 and Cx52.6 contribute to hemichannel currents, and that Cx55.5 may have an additional regulatory function enhancing the amplitude of hemichannel currents.

Celecoxib and acetylbritannilactone interact synergistically to suppress breast cancer cell growth via COX-2-dependent and -independent mechanisms

The use of celecoxib is associated with a significant decrease in breast cancer risk. However, the long-term use of high-dose celecoxib might be limited owing to cardiovascular side effects. In this study, we found that acetylbritannilactone (ABL), extract from a Chinese medicinal herb, could reduce celecoxib dose and potentiate the growth-inhibitory effect in breast cancer cells. ABL enhanced the apoptotic effect of celecoxib in COX-2-expressing cells, but had little effect in COX-2-negative cells. The apoptosis induced by the combination treatment disappeared when COX-2 was knocked down, whereas the lack of apoptotic effects in COX-2-negative cells was reversed after COX-2 transfection. However, the combination treatment induced a G(0)/G(1) phase arrest independent of whether or not the cells expressed COX-2. The G(0)/G(1) arrest was attributed to a decreased expression of cyclinD1, cyclinE, CDK2 and CDK6, especially the upregulation of p21. In addition, inhibition of Akt and p38 signaling pathways was required by the synergism, as the constitutively active Akt and p38 protected cells against apoptosis and cell cycle arrest induced by the combination treatment. In vivo, administration of celecoxib and ABL were more effective than the individual agents against xenograft tumor growth. Thus, our data suggested that the combinatorial approach of celecoxib and ABL might be helpful for breast cancer treatment.

Zinc modulation of hemi-gap-junction channel currents in retinal horizontal cells

Hemi-gap-junction (HGJ) channels of retinal horizontal cells (HCs) function as transmembrane ion channels that are modulated by voltage and calcium. As an endogenous retinal neuromodulator, zinc, which is coreleased with glutamate at photoreceptor synapses, plays an important role in shaping visual signals by acting on postsynaptic HCs in vivo. To understand more fully the regulation and function of HC HGJ channels, we examined the effect of Zn(2+) on HGJ channel currents in bass retinal HCs. Hemichannel currents elicited by depolarization in Ca(2+)-free medium and in 1 mM Ca(2+) medium were significantly inhibited by extracellular Zn(2+). The inhibition by Zn(2+) of hemichannel currents was dose dependent with a half-maximum inhibitory concentration of 37 microM. Compared with other divalent cations, Zn(2+) exhibited higher inhibitory potency, with the order being Zn(2+) > Cd(2+) approximately Co(2+) > Ca(2+) > Ba(2+) > Mg(2+). Zn(2+) and Ca(2+) were found to modulate HGJ channels independently in additivity experiments. Modification of histidine residues with N-bromosuccinimide suppressed the inhibitory action of Zn(2+), whereas modification of cysteine residues had no significant effect on Zn(2+) inhibition. Taken together, these results suggest that zinc acts on HGJ channels in a calcium-independent way and that histidine residues on the extracellular domain of HGJ channels mediate the inhibitory action of zinc.

Targeting retinal dopaminergic neurons in tyrosine hydroxylase-driven green fluorescent protein transgenic zebrafish

PURPOSE

Dopamine plays key roles in a variety of basic functions in the central nervous system. To study developmental and functional roles of dopaminergic cells in zebrafish, we have generated a transgenic line of zebrafish expressing green fluorescent protein (GFP) under the control of the tyrosine hydroxylase (th1) promoter.

METHODS

A 12 kb gene fragment that contains the th1 promoter was isolated and ligated to the MmGFP coding sequence, linearized, microinjected into 1-2 cell stage embryos and the founders crossed with wild-type fish to screen for transgenic lines. Tg(-12th:MmGFP) embryos were visualized under fluorescence microscopy for GFP expression during development. Confocal microscopy was used to visualize GFP-labeled cells in the living whole mount retina and immunostained vertical sections of adult zebrafish retina. Single-cell reverse transcription polymerase chain reaction (RT-PCR) was performed on individual GFP+ cells collected from dispersed retinal cell cultures for th1 and dopamine transporter (dat). Loose-patch recordings of spike activity of GFP+ neurons were made in isolated whole mount retinas.

RESULTS

th1 promoter-driven GFP exhibited robust expression in the brain and retina during zebrafish development. In juvenile and adult fish retinas, GFP was expressed in cells located in the inner nuclear layer. Immunocytochemistry with antibodies for GFP and TH showed that 29+/-2% of GFP-labeled cells also expressed TH. Two subpopulations of GFP-labeled cells were identified by fluorescent microscopy: bright GFP-expressing cells and dim GFP-expressing cells. Seminested single-cell RT-PCR showed that 71% of dim GFP-expressing cells expressed both th and dat mRNA. Loose-patch voltage-clamp recording from dim GFP-labeled cells in retinal whole mounts revealed that many of these dopaminergic neurons are spontaneously active in darkness.

CONCLUSIONS

Although this Tg(-12th:MmGFP) line is not a completely specific reporter for dopaminergic neurons, using relative GFP intensity we are able to enrich for the selection of retinal dopaminergic cells in vitro and in situ in molecular and electrophysiological experiments. This transgenic line provides a useful tool for studying retinal dopaminergic cells in the zebrafish.

Functional heterogeneity of retinal dopaminergic neurons underlying their multiple roles in vision

Dopaminergic neurons play key roles in the CNS, mediating basic mechanisms of vision, movement, motivation, and mood. The most accessible dopaminergic neurons of the vertebrate CNS are the dopaminergic amacrine cells of the retina. Here, we have characterized the intrinsic neural activity, synaptic input, and light responses of retinal dopaminergic neurons in situ, using targeted electrophysiological recordings of fluorescent neurons in TH::RFP (tyrosine hydroxylase gene promoter::red fluorescent protein) transgenic mice. Dopaminergic amacrine cells exhibit two classes of intrinsic bursting in the dark, shaped by inhibitory synaptic inputs, and two classes of light responses, ON-transient and ON-sustained, as well as light-independent activity, tuned to mediate specific dopaminergic functions in vision. The functional heterogeneity revealed in dopaminergic amacrine cells provides a cellular basis for the multiple roles of dopaminergic amacrine neurons in vision and is likely a general property of dopaminergic neurons throughout the CNS.

Gene profiling after knocking-down expression of nucleostemin in Hela cells using oligonucleotide DNA microarray

Nucleostemin (NS) is preferentially and exclusively expressed in the stem cells and cancer cells, but not in differentiated adult tissues and cells. NS is likely to take part in controlling the proliferation and differentiation switch in stem cells and progenitor cells. Its deregulation in cancer also contributes to the elevated proliferation and undifferentiation of cancer cells. However, the mechanisms by which NS helps to maintain both cancer and stem cells in undifferentiated state remain unclear. In this study, we carried out gene profilings using oligonucleotide DNA microarray after knocking down the expression of NS in Hela cells. Of the 21,329 genes, 200 genes were found differentially expressed in NS silenced Hela cells with > 2 fold ratio (either > 2 or < 0.5). Category analysis indicated these differential genes were mainly related with cancer pathogenesis, cell death, cell growth and proliferation. NS related gene pathway analysis suggested NS was mostly involved in the networks of cell cycle and differentiation controls. p53 may not be the only partner of NS in its regulated pathways. c-Myc may directly or indirectly interact with it to control the proliferation and differentiation switch in cancer cells. Our study provides a general view of the NS-target genes, and indicates the possible pathways in which NS plays its role in proliferation control.

Modulation of A-type potassium currents in retinal horizontal cells by extracellular calcium and zinc

Extracellular Ca2+ and Zn2+ influence many aspects of retinal function. Here, we examined the effect of external Ca2+ and Zn2+ on potassium channels of retinal horizontal cells. When extracellular Ca2+ was lowered from 3 mM to 0.3 mM, horizontal cell transient outward currents elicited by voltage steps from resting membrane potential (−70 mV) were decreased by approximately 50%, whereas the sustained currents remained unchanged. This effect was due to a hyperpolarizing shift in the steady-state inactivation curve of A-type K+ currents when extracellular Ca2+ concentration was lowered. The mean half inactivation potential of the steady-state inactivation curves was hyperpolarized from −56.3 ± 4.7 mV in 3 mM Ca2+ to −76.4 ± 3.9 mV in 0.3 mM Ca2+. Neither the state-steady activation curve nor the kinetics of inactivation was significantly changed in low extracellular Ca2+. The addition of 30 μM Zn2+ restored peak outward currents in 0.3 mM Ca2+. The half inactivation voltages were depolarized from −70 ± 2.8 mV in 0.3 mM Ca2+ to −56 ± 2.6 mV in 0.3 mM Ca2+ plus 30 μM Zn2+. Taken together, the results indicate that external Ca2+ and Zn2+ maintain the activity of A-type potassium channels in retinal horizontal cells by influencing the voltage dependence of steady-state inactivation.

Circadian organization of the mammalian retina

The mammalian retina contains an endogenous circadian pacemaker that broadly regulates retinal physiology and function, yet the cellular origin and organization of the mammalian retinal circadian clock remains unclear. Circadian clock neurons generate daily rhythms via cell-autonomous autoregulatory clock gene networks, and, thus, to localize circadian clock neurons within the mammalian retina, we have studied the cell type-specific expression of six core circadian clock genes in individual, identified mouse retinal neurons, as well as characterized the clock gene expression rhythms in photoreceptor degenerate rd mouse retinas. Individual photoreceptors, horizontal, bipolar, dopaminergic (DA) amacrines, catecholaminergic (CA) amacrines, and ganglion neurons were identified either by morphology or by a tyrosine hydroxylase (TH) promoter-driven red fluorescent protein (RFP) fluorescent reporter. Cells were collected, and their transcriptomes were subjected to multiplex single-cell RT-PCR for the core clock genes Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1. Individual horizontal, bipolar, DA, CA, and ganglion neurons, but not photoreceptors, were found to coordinately express all six core clock genes, with the lowest proportion of putative clock cells in photoreceptors (0%) and the highest proportion in DA neurons (30%). In addition, clock gene rhythms were found to persist for >25 days in isolated, cultured rd mouse retinas in which photoreceptors had degenerated. Our results indicate that multiple types of retinal neurons are potential circadian clock neurons that express key elements of the circadian autoregulatory gene network and that the inner nuclear and ganglion cell layers of the mammalian retina contain functionally autonomous circadian clocks.

Circadian rhythm of Period1 clock gene expression in NOS amacrine cells of the mouse retina

The vertebrate retina contains self-sustained circadian clocks that broadly influence retinal physiology. In the present study, we have examined the relationship of nitric oxide, GABAergic and glycinergic inner retinal neurons with expression of a reporter for the circadian clock gene Period1 (Per1). Using Per1 : :GFP transgenic mice, we found that 72% of brain nitric oxide synthase (bNOS) expressing amacrine cells (NOS amacrine cells) sampled during the daytime were also immunoreactive for Per1-driven GFP. The number of bright GFP(+) NOS(+) cells was greater at Zeitgeber time (ZT) 10 than at 22, and this pattern persisted in retinas from animals which were placed in constant darkness [Circadian time (CT) 10 vs. 22]. Intensities of GFP-IR for individual NOS amacrine cells were analyzed at ZT4, 10, 16 and 22, with the peak value occurring at ZT10. Similar results were obtained from retinas sampled at CT4, 10, 16 and 22 in constant darkness, indicating that an endogenous circadian clock drives the transcription of the Per1 clock gene within NOS amacrine cells. The predominance of Per1 : :GFP(+) amacrine cells (82%), was immunoreactive to glutamate decarboxylase 65, but no Per1 : :GFP(+) amacrine cells colabeled with a glycine transporter 1 antibody. The results demonstrate circadian rhythms in Per1 promoter activation in nitric oxide (NO) and GABA secreting amacrine cells, and suggest that NO and GABA could be controlled by circadian clock mechanisms in the mammalian retina.

Characterization of genetically labeled catecholamine neurons in the mouse retina

Mouse neurons were labeled transgenically with red fluorescent protein (RFP) driven by the tyrosine hydroxylase (TH) promoter and observed in living retinas and brain slices. Two types of retinal amacrine cells expressed TH::RFP. One type had large cell bodies, processes that ramified in S1 of the inner plaxiform layer (IPL) and were TH immunoreactive, identifying them as dopaminergic neurons. A second type had smaller somas, ramified in S3 and lacked TH. Dopaminergic cells had large dendritic fields and exceptionally long axon-like processes, whereas type 2 cells were more compact. Neither cell type exhibited tracer coupling. Thus, murine retinal dopaminergic neurons exhibit functional anatomy similar to their primate counterparts and TH::RFP mice are useful for in situ characterization of catecholaminergic neurons.

Cellular location and circadian rhythm of expression of the biological clock gene Period 1 in the mouse retina

The cellular location and rhythmic expression of Period 1 (Per1) circadian clock gene were examined in the retina of a Per1::GFP transgenic mouse. Mouse Per1 (mPer1) RNA was localized to inner nuclear and ganglion cell layers but was absent in the outer nuclear (photoreceptor) layer. Green fluorescent protein (GFP), which was shown to colocalize with PER1 protein, was found in a few subtypes of amacrine neuron, including those containing tyrosine hydroxylase, calbindin, and calretinin, but not in cholinergic amacrine cells. A small subset of ganglion cells also contained GFP immunoreactivity (GFP-IR), but the melanopsin-containing subtype, which projects to the suprachiasmatic nuclei (SCN), lacked GFP-IR. Although the intensity of GFP-IR varied among the populations of amacrine cells at each time point that was examined, both diurnal and circadian rhythms were found for the fraction of neurons showing strong GFP-IR, with peak expression between Zeitgeber/circadian (ZT/CT) times 10 and 14. In SCNs that were examined in the same mice used for the retinal measures, the peak in GFP-IR also occurred at approximately ZT/CT 10. Our results are the first to demonstrate a circadian rhythm of a biological clock component in identified neurons of a mammalian retina.

Suppression by zinc of AMPA receptor-mediated synaptic transmission in the retina

Zinc is strikingly co-localized with glutamate-containing vesicles in the synaptic terminals of retinal photoreceptors, and it is thought to be co-released with glutamate onto postsynaptic neurons such as horizontal cells and bipolar cells. Here we examined exogenous zinc modulation of glutamate receptors on cultured retinal horizontal cells using patch-clamp recording and endogenous zinc effect on intact horizontal cells using intracellular recording techniques. Application of 3, 30, and 300 microM zinc reduced the whole cell peak current of response to 200 microM glutamate by 2, 30, and 56%, respectively. Zinc suppression of glutamate response persisted in the presence of 10 microM cyclothiazide (CTZ). Glutamate responses of outside-out patches were completely abolished by 30 microM 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (GYKI 52466), and the receptor desensitization was blocked by 30 microM CTZ, indicating that receptor target for the zinc action on horizontal cells is alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproponic acid (AMPA) receptors. Zinc decreased the amplitude of outside-out patch peak current without an effect on either its 10-90% rise time or the rate of receptor desensitization. Dose-response curves for glutamate show that zinc reduced the maximal current evoked by glutamate and increased EC(50) from 50 +/- 3 to 70 +/- 6 microM without changing the Hill coefficient. Chelation of endogenous zinc with 1 mM Ca-EDTA depolarized horizontal cells in the intact retina by 3 mV, consistent with relief of the partial glutamate receptor inhibition by zinc. Overall, the results describe a unimodal form of zinc modulation of AMPA-type glutamate receptor responses not previously described in native neuronal preparations and a novel role for endogenous zinc in modulating neurotransmission.

Gating of retinal horizontal cell hemi gap junction channels by voltage, Ca2+, and retinoic acid

PURPOSE

Hemi gap junction (HGJ) channels, precursors of gap junctional channels, are functionally expressed in retinal horizontal cells where they may play roles in osmoeregulation and ephaptic regulation of synaptic feedback to photoreceptors. In this study we examined mechanisms of gating of these channels by transmembrane voltage, Ca2+ and retinoic acid (RA).

METHODS

Experiments were performed on cultured bass horizontal cells using the conventional whole cell patch clamp configuration.

RESULTS

HGJ currents in isolated bass horizontal cells, revealed by perfusion with Ca2+ free media, were opened by positive holding potentials and inhibited by negative holding potentials. These currents were also inhibited by external application of either Ca2+ or RA. Using a rapid perfusion system, the latency of 2 mM Ca2+ to begin channel closure was unmeasurably brief, whereas the latency for 30 microM RA action was 177+/-9 ms (mean+/-standard error of the mean). The total inhibition of HGJ channel currents by coapplication of 0.3 microM RA and 100 microM Ca2+ was less than the sum of inhibition by RA alone and Ca2+ alone suggesting that the actions of RA and Ca2+ were not independent. In the presence of 0.3 microM RA, the half maximal concentration for Ca2+ inhibition was increased from a control value of 192 microM to 375 microM without affecting maximal inhibition. Similarly, the half maximal concentration for RA inhibition was increased from a control value of 0.44 microM to 1.1 microM without affecting maximal inhibition in the presence of 100 microM Ca2+.

CONCLUSIONS

These results suggest that horizontal cell HGJ channels are closed by the normal negative resting potentials of these cells. Extracellular Ca2+ and the retinal neuromodulator RA also act to close HGJ channels through mechanisms or sites which are not independent.

Direct gating by retinoic acid of retinal electrical synapses

Retinoic acid (RA), a signaling molecule derived from vitamin A, controls growth and differentiation of a variety of cell types through regulation of gene transcription. In the vertebrate retina, RA also regulates gap junction-mediated physiological coupling of retinal neurons through a nontranscriptional mechanism. Here we report that RA rapidly and specifically modulates synaptic transmission at electrical synapses of cultured retinal horizontal cells through an external RAR(beta)(/gamma)-like binding site, the action of which is independent of second messenger cascades. External application of all-trans retinoic acid (at-RA) reversibly reduced the amplitude of gap junctional conductance in a dose-dependent manner, but failed to affect non-gap-junctional channels, including glutamate receptors. In contrast, internal dialysis with at-RA was ineffective, indicating an external site of action. Selective RAR(beta)(/gamma) ligands, but not an RAR(alpha)-selective agonist, mimicked the action of at-RA, suggesting that gating of gap junctional channels is mediated through an RAR(beta)(/gamma)-like binding site. At-RA did not act on gap junctional conductance by lowering [pH](i) or by increasing [Ca(2+)](i). A G protein inhibitor and protein kinase inhibitors did not block at-RA uncoupling effects indicating no second messenger systems were involved. Direct action of at-RA on gap junction channels was further supported by its equivalent action on whole-cell hemi-gap-junctional currents and on cell-free excised patch hemichannel currents. At-RA significantly reduced single-channel open probability but did not change unitary conductance. Overall, the results indicate that RA modulates horizontal cell electrical synapses by activation of novel nonnuclear RAR(beta)(/gamma)-like sites either directly on, or intimately associated with, gap junction channels.

Characterization of T cell lines derived from glatiramer-acetate-treated multiple sclerosis patients

We analyzed the effects of glatiramer acetate (GA) therapy on in vitro proliferative responses and cytokine production by lymphocytes derived from multiple sclerosis patients receiving this therapy. We confirmed that lymphocytes derived from GA naïve patients show a high frequency of response when initially exposed to GA in vitro; this frequency decreased following GA therapy. The frequency of lymphocytes responding to whole MBP stimulation did not change with GA therapy. GA- and MBP-specific T cell lines generated from these patients by repeated cycles of in vitro stimulation did not cross react. Some (23%) whole MBP-reactive T cell lines did cross react with MBP peptide 83-99. The mean levels of interferon (IFN) gamma secretion and the mean ratio of IFN-gamma/IL-5 were lower for GA-reactive cell lines, derived from patients both prior to and during GA therapy, compared to MBP-reactive T cell lines. The proportion of IFN-gamma(+) cells in unfractionated lymphocyte preparations derived from the GA-treated patients did not differ from that found for healthy controls. Our findings indicate that GA-reactive T cell lines derived from GA-treated MS patients continue to show a relative Th2 cytokine bias consistent with a bystander suppressor function. GA treatment is not associated with a cytokine phenotype shift in the total T cell or MBP-reactive T cell populations.

Isolation and characteristics of autoreactive T cells specific to aggrecan G1 domain from rheumatoid arthritis patients

Our previous work showed that the cartilage proteoglycan aggrecan could induce an erosive polyarthritis and spondylitis in BALB/c mice and the G1 globular domain of the aggrecan (G1) contained the arthritogenic region. To elucidate whether autoreactive T cells to G1 are expressed in rheumatoid arthritis patients, we analyzed the frequency of human G1-specific T cells in the peripheral blood of five rheumatoid arthritis patients and tried to establish G1-reactive T cell lines from these rheumatoid arthritis patients. The results showed that the G1-specific T cells in PBL were detectable at the range of 4.97 +/- 0.5 x 10(-6) in peripheral blood lymphocytes. We have also generated 15 G1-specific T lymphocyte lines from these patients with a standard split-well method. All these cells expressed fine specificity to human recombinant G1, but not to unrelated antigen. All the 15 lines expressed a pan-T cell marker and 13 of them selectively used the alphabeta T cell receptor. Two of them used gammadelta T cell receptor. The 13 of these T cell lines was CD4 positive. One line expressed CD8. One line expressed both CD4 and CD8. Moreover, 14 out of 15 lines expressed the Th-1 cytokine profile, characterized by interferon-gamma positivity and IL-4 negativity. No Th-2 type cell line was generated. These data provide strong evidence in favor of the presence of autoreactive T cells in the rheumatoid arthritis patients. What is the mechanism(s) that these autoreactive T cells attack self-target and whether these G1-specific, Th-1 type T cell lines can induce arthritis in immune deficiency mice are currently under investigation.

Electrical coupling of retinal horizontal cells mediated by distinct voltage-independent junctions

Electrical coupling between H2 horizontal cell pairs isolated from the hybrid bass retina was studied using dual whole-cell, voltage-clamp technique. Voltage-dependent inactivation of junctional currents in response to steps in transjunctional voltage (Vj) over a range of +/-100 mV was characterized for 89 cell pairs. Approximately one-quarter of the pairs exhibited strongly voltage-dependent junctions (>50% reduction in junctional current at +/-100 mV), another quarter of the pairs exhibited voltage-independent junctional current (<5% reduction at +/-100 mV), and the remainder of the pairs exhibited intermediate values for voltage inactivation. We focused on further characterizing the Vj-independent junctions of horizontal cells, which have not been described previously in detail. When Lucifer Yellow dye was included in one recording pipette, pairs exhibiting Vj-independent coupling showed no (9/12), or limited (3/12), passage of dye. Vj-independent coupling was markedly less sensitive to the modulators SNP (100-300 microM, -9% reduction in coupling) and dopamine (100-300 microM, -6%) than were Vj-dependent junctions (-45% and -44%). However, simultaneous application of both SNP and dopamine significantly reduced Vj-independent coupling (-56%). Both Vj-independent and Vj-dependent junctions were blocked by DMSO (1-2%), but Vj-independent junctions were not blocked by heptanol. Single-channel junctional conductances of Vj-independent junctions range from 112-180 pS, versus 50-60 pS for Vj-dependent junctions. The results reveal that Vj-independent coupling in a subpopulation of horizontal cells from the hybrid bass retina is mediated by cellular junctions with physiological and pharmacological characteristics distinct from those previously described in fish horizontal cells.

GABA modulates color-opponent bipolar cells in carp retina

In the present work, the effects of gamma-aminobutyric acid (GABA) were examined while recording intracellularly from color-opponent bipolar cells in the isolated, superfused carp retina. Bath-applied GABA differentially suppressed light responses of R/G cells, which depolarized and hyperpolarized, respectively, in response to red and green flashes, and G/R cells, which showed the opposite responses. In either R/G or G/R cells, the response driven by input from red cones was invariably suppressed to a greater extent. Such effects of GABA were completely blocked by picrotoxin, but only partially by bicuculline, suggesting that the GABAC receptor, in addition to the GABAA receptor, may also be involved. It is postulated that GABA modulates the color-opponent bipolar cells either through activating GABA receptors on these cells directly or those on cone terminals indirectly.