Macrolide resistance of Mycoplasma pneumoniae in several regions of China from 2013 to 2019

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were ≥ 64 μg/ml, and the MICs of tetracycline and levofloxacin were ≤ 0.5 μg/ml and ≤ 1 μg/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

Proteomic and Phenotypic Studies of Mycoplasma pneumoniae Revealed Macrolide-Resistant Mutation (A2063G) Associated Changes in Protein Composition and Pathogenicity of Type I Strains

Mycoplasma pneumoniae (MP) is an important respiratory pathogen, the prevalence of macrolide-resistant MP (mainly containing A2063G mutation in 23S rRNA) increased in recent years. Epidemiological studies suggest a higher prevalence of type I resistant (IR) strains than corresponding sensitive (IS/IIS) strains, but not type II resistant (IIR) strains. Here, we aimed to analyze the factors underlying the altered prevalence of IR strains. First, proteomic analyses exhibit the protein compositions were type specific, while more differential proteins were detected between IS and IR (227) than IIS and IIR strains (81). mRNA level detection suggested posttranscriptional regulation of these differential proteins. Differential protein-related phenotypic changes were also detected: (i) P1 abundance was different between genotypes (I < II, IR < IS), the adhesion of MPs showed accordance to P1 abundance within IS and IIS strains; (ii) type I, especially IR, strains had a higher proliferation rate, which is potentially associated with differential proteins participating in glycolysis and one carbon pool metabolisms; (iii) A549 cells infected with IR strains had lower activity of caspase-3 and higher levels IL-8, but the differences were not significant between groups (P > 0.05). Correlations of P1 abundance to caspase-3 activity and proliferation rate to the level of IL-8 were obtained. These results suggest changes in protein composition influenced the pathogenicity of MP, especially in IR strains, which may impact the prevalence of MP strains of different genotypes. IMPORTANCE The prevalence of macrolide-resistant MPs increased the difficulty in treatment of MP infections and posed potential threats to children's health. Epidemiological studies showed a high prevalence of IR-resistant strains (mainly A2063G in 23S rRNA) in these years. However, the trigger mechanisms for this phenomenon are not clear. In this paper, proteomic and phenotypic studies suggest that IR strains have reduced levels of multiple adhesion proteins and increased proliferation rate, which may lead to higher transmission rate of IR strains in the population. This suggests that we should pay attention to the prevalence of IR strains.

[Epidemiological characteristics and serum antibody detection of a COVID-19 aggregated outbreak in vaccinated population]

An epidemiological investigation was conducted on a cluster epidemic of COVID-19 in the vaccinated population in Beijing in 2022, and serum samples were collected from 21 infected cases and 61 close contacts (including 20 cases with positive nucleic acid in the isolation observation period). The results of antibody detection showed that the IgM antibody of two infected persons was positive, and the IgG antibody positive rates of patients who were converted, not converted to positive and infected persons were 36.84% (7/19), 63.41% (26/41) and 71.43% (15/21), respectively. About 98.78% of patients had been vaccinated with the SARS-CoV-2 inactivated vaccine. The positive rate of IgG antibody in patients immunized with three doses of vaccine was 86.00% (43/50), which was higher than that in patients with one or two doses [16.12% (5/31)]. The antibody level of M (Q₁, Q₃) in patients immunized with three doses was 4.255 (2.303, 7.0375), which was higher than that in patients with one or two doses [0.500 (0.500, 0.500)] (all P values<0.001). The antibody level of patients who were vaccinated less than three months [7.335 (1.909, 7.858)] was higher than that of patients vaccinated more than three months after the last vaccination [2.125 (0.500, 4.418)] (P=0.007). The positive rate and level of IgG antibody in patients who were converted to positive after three doses were 77.78% (7/9) and 4.207 (2.216, 7.099), respectively, which were higher than those in patients who were converted after one or two doses [0 and 0.500 (0.500, 0.500)] (all P values<0.05).

Serum cytokine profiling reveals different immune response patterns during general and severe Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is an important human pathogen that mainly affects children causing general and severe Mycoplasma pneumoniae pneumonia (G/SMPP). In the present study, a comprehensive immune response data (33 cytokines) was obtained in school-age children (3-9 years old) during MPP, aiming to analyze the immune response patterns during MPP. At acute phase, changes of cytokines were both detected in GMPP (24/33) and SMPP (23/33) groups compared to the healthy group (p < 0.05), with 20 identical cytokines. Between MPP groups, the levels of 13 cytokines (IL-2, IL-10, IL-11, IL-12, IL-20, IL-28A, IL-32, IL-35, IFN-α2, IFN-γ, IFN-β, BAFF, and TSLP) were higher and three cytokines (LIGHT, OPN and CHI3L1) were lower in the SMPP group than in the GMPP group (p < 0.05). Function analysis reveals that macrophage function (sCD163, CHI3L1) are not activated in both MPP groups; difference in regulatory patterns of T cells (IL26, IL27, OPN, LIGHT) and defective activation of B cells (BAFF) were detected in the SMPP group compared to the GMPP group. Besides, the level of osteocalcin; sIL-6Rβ and MMP-2 are both decreased in MPP groups at acute and convalescent phases compared to the healthy group, among which the levels of sIL-6Rβ and MMP-2 showed negative correlations (p < 0.1) to the application of bronchial lavage in SMPP group, indicating their roles in the development of MPP. At the convalescent phase, more cytokines recovered in GMPP (18) than SMPP (11), revealing better controlled immune response during GMPP. These results reveal different immune response patterns during GMPP and SMPP. In addition, the differentiated cytokines may serve as potential indicators of SMPP; early intervention on immune response regulations may be helpful in reducing the severity of SMPP.

Cell damage and neutrophils promote the infection of Mycoplasma pneumoniae and inflammatory response

Mycoplasma pneumoniae (MP) is an important respiratory pathogen of human. The infection of MP can cause direct damage and immune damage in lung, resulting in Mycoplasma pneumoniae pneumonia (MPP). In this study, we aim to investigate the pathogenesis of MPP by detecting the proliferation of MP under conditions of cell damages and neutrophils in vitro. Firstly, we found the supplements of intracellular fluid, protein and RNA derived from intracellular fluid of A549 cells contribute to the survival of MP, thereby promoting the infection of MP. Cell damage can also significantly contribute to the survival of MP without supplements. At the same time, the additions of supplements contribute to apoptosis and the expression of IL-8 and IL-1β. Further, we found live neutrophils show bactericidal activity to MP, and the phagocytosis of MP promotes apoptosis of neutrophils. When co-incubated with MP and A549 cells, the proliferation of MP in the high neutrophils proportion groups were accelerated with functional decline of neutrophils, and the level of extracellular IL-1β showed a time and dose dependent manner to neutrophils. These results suggest that the release of intracellular nutrients by damaged cells and functional decline of neutrophils can promote the infection of MP and play roles in the activation of inflammatory response. Therefore, lung damage and infiltration of neutrophils would be important factors affecting the development of MPP.

Efficacy and safety of Qinxiang Qingjie oral solution for the treatment of influenza in children: a randomized, double-blind, multicenter clinical trial

BACKGROUND

Qinxiang Qingjie (QXQJ), an oral solution containing various Chinese herbs, is indicated for pediatric upper respiratory tract infections. The treatment of influenza also shows potential advantages in shortening the duration of illness and improving symptoms. However, there is still a lack of high-quality clinical evidence to support this. The trial was to explore the efficacy and safety of QXQJ for treating pediatric influenza and provide an evidence-based basis for expanding its applicability.

METHODS

A randomized, double-blind, double-dummy, positive-controlled, multicenter clinical trial was conducted in 14 hospitals in China. Children aged 1-13 years with influenza and "exterior and interior heat syndromes" as defined by traditional Chinese medicine (TCM) were randomly assigned to two groups with 1:1 radio. Children in the test group received QXQJ oral solution and oseltamivir simulant, while the control group received oseltamivir phosphate granules and QXQJ simulant. The duration of treatment was five days, followed by a two-day follow-up period. The primary endpoint was the clinical recovery time. Secondary endpoints included the time to defervescence, incidences of complications and severe or critical influenza, negative conversion rate, improvement of TCM syndromes, and safety profiles of the therapeutics, which mainly contained the adverse clinical events and adverse drug reactions.

RESULTS

A total of 231 children were randomized to either the QXQJ (n=117) or oseltamivir (n=114) group. The FAS and PPS results showed that both groups experienced a median clinical recovery time of three days (P>0.05). The median time to defervescence of both groups were 36 hours in FAS and PPS (P>0.05), and two groups did not differ in terms of the other secondary endpoints (P>0.05). 14 patients (12.39%) in the QXQJ group and 14 patients (12.50%) in the oseltamivir group reported at least one adverse event, respectively. One serious adverse event occurred in the QXQJ group. There was no significant difference in the incidence of adverse events or adverse drug reactions between the groups.

CONCLUSIONS

The efficacy of QXQJ oral solution was comparable to that of oseltamivir for treating influenza in children, with an acceptable safety profile.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1900021060.

Mechanism of Infantile Feire Kechuan Oral Solution against Mycoplasma pneumoniae infection of A549 cells

BACKGROUND

Mycoplasma pneumoniae is a leading cause of community-acquired respiratory infections. Infantile Feire Kechuan Oral Solution (IFKOS) is effective for treatment of M. pneumoniae infection. The aim of this study was to explore the potential mechanism of IFKOS against M. pneumoniae infection in basal epithelial human lung adenocarcinoma A549 cells.

METHODS

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the effects of IFKOS on the viability of A549 cells infected with M. pneumoniae. Optical microscopy was used to observe cell morphology and a Muse cell analyzer was used to assess apoptosis and the cell cycle phase. Enzyme-linked immunosorbent assays were employed to assess the expression levels of interleukin (IL)-4, IL-6, IL-8, IL-17, tumor necrosis factor (TNF)-α, interferon (IFN)-α, and IFN-γ.

RESULTS

Under certain conditions, M. pneumoniae infection reduced the viability and inhibited the proliferation of A549 cells, promoted early apoptosis, and arrested cells in the G0/G1 phase, thus shortening the S and G2/M phases (all p < 0.05). M. pneumoniae also upregulated expression of IL-8 and TNF-α and downregulated that of IL-6 (p < 0.05), which switched the immune balance of Th1/Th2 to Th1 cells. IFKOS (5.531 mg/mL) improved the viability and proliferation of M. pneumoniae-infected A549 cells, mitigated early apoptosis, and reversed cell cycle arrest in the G0/G1 phase, thereby extending the S and G2/M phases (all, p < 0.05). IFKOS downregulated expression of IL-8 and TNF-α and upregulated that of IL-6 (p < 0.01), thereby reversing the immune imbalance of Th1/Th2. Secretion of IL-4, IL-17, IFN-α, and IFN-γ was not observed.

CONCLUSION

IFKOS played a protective role in the regulation of cell viability, apoptosis, the cell cycle, and Th1/Th2 immune imbalance induced by M. pneumoniae infection and conveyed an anti-inflammatory effect in A549 cells.

[Establishment and validation of prognostic risk score model for esophageal squamous cell carcinoma based on immune related genes]

Objective: To find the biomarkers that accurately predict the survival of patients with esophageal squamous cell carcinoma (ESCC). Methods: The immune related genes that were significantly related to the overall survival (OS) of patients with ESCC were screened from The Cancer Genome Atlas (TCGA) database to construct a prognostic risk score model. The prognoses of the high-risk and low-risk groups were compared by Kaplan-Meier method. The accuracy of the model was evaluated by the receiver operating characteristic (ROC) curve. Tumor tissue samples of 83 patients with pathological diagnosis of ESCC were collected from Anyang Cancer Hospital for external verification. Cox regression analysis was used to comprehensively evaluate the effects of prognostic risk score and various clinical characteristics on OS of patients with ESCC. Results: Seven immune-related genes that were significantly related to survival prognosis were selected from the TCGA database and included in the prognostic risk score model, which were S100A12, SLC40A1, FABP9, TNFSF10, IGHA2, IL1F10, and STC2. The 1- and 2-year survival rates of the low-risk group (40 cases) were 94.3% and 82.5%, respectively, while those of the high-risk group (40 cases) were 75.9% and 32.9%, respectively.The prognosis of the high-risk group was worse than that of the low-risk group (P<0.001). The 83 external validation samples obtained consistent results by using the prognostic risk score model. The prognostic risk score was positively correlated with the content of CD4(+) T lymphocytes in ESCC (r(s)=0.259, P=0.020), but not correlated with the content of B lymphocytes, CD8(+) T lymphocytes, neutrophils, macrophages or dendritic cells (P>0.05). Conclusions: S100A12, SLC40A1, FABP9, TNFSF10, IGHA2, IL1F10, and STC2 were risk genes significantly associated with OS of patients with ESCC. The prognostic risk score was an independent prognostic factor for the OS of patients with ESCC, and it was correlated with the content of CD4(+) T lymphocytes in ESCC tissue.

CircRNA_100782 promotes roliferation and metastasis of gastric cancer by downregulating tumor suppressor gene Rb by adsorbing miR-574-3p in a sponge form

OBJECTIVE

The aim of this study is to investigate the expression levels of circRNA_100782 in gastric cancer tissues, and its function of regulating tumor suppressor gene Rb by absorbing miR-574-3p in a sponge form.

PATIENTS AND METHODS

qRT-PCR was performed to detect the expressions of circRNA_100782 at different stages during gastric cancer tissues. CCK-8 assay was performed to evaluate the osteoclast proliferation and differentiation. The correlation between miR-574-3p and circRNA_100782 was detected by statistical analysis. Bioinformatics and Luciferase assay were performed to explore the interaction and binding site of circRNA_100782 and miR-574-3p. The mice Rb 3'-UTR were cloned into the Luciferase reporter vector and miR-574-3p binding mutants were constructed to validate the inhibited regulation of miR-574-3p to the expression of Rb.

RESULTS

In the current study, compared with adjacent non-cancerous normal tissues, the expressions of circRNA_100782 and Rb were both downregulated in human gastric cancer cells. Through qRT-PCR and CCK-8 assay, we found that the expression of circRNA_100782 is related to the proliferation of gastric cancer cells. Besides, we also found that circRNA_100782 regulated the migration ability of gastric cancer cells through transwell assay. The bioinformatics prediction and luciferase assay demonstrated that circRNA_100782 can serve as a molecular sponge to further regulate the expression of Rb by sponging with miR-574-3p; moreover, circRNA_100782 can serve as a ceRNA for miR-574-3p to further regulate the expression of Rb.

CONCLUSIONS

In this research, we discovered that circRNA_100782 was downregulated in gastric cancer cells and is associated with cell proliferation and invasion by inhibiting tumor suppressor gene Rb by interacting with miR-574-3p.

Allele-specific real-time PCR testing for minor macrolide-resistant Mycoplasma Pneumoniae

Background

The point mutations in 23S rRNA gene of Mycoplasma pneumoniae (M. pneumoniae) can lead to high-level resistance to macrolides. This study aimed to evaluate allele-specific real-time PCR (ASPCR) to detect the resistance-related mutations located at positions A2063G and A2064G of 23S rRNA gene.

Methods

We detected 178 pharyngeal swab specimens and calculated the proportions of resistant and sensitive quasispecies using ASPCR assays. ASPCR assays can detect down to 10 copies of 23S rRNA gene and achieved sensitivities of < 0.1% for A2063G and A2064G. We also compared the findings of ASPCR with the results of nested PCR with sequencing.

Results

Of 178 samples, 164 were found to have M. pneumoniae including 90.85% (149/164) samples with macrolide-resistant M. pneumoniae (MRMP) quasispecies by ASPCR, while 153 were found to be M. pneumoniae-positive including 71.90% (110/153) samples with MRMP quasispecies by nested PCR with sequencing. Of the 164 M. pneumoniae-positive samples, 61.59% (101/164) had the mixed population of wild-type and mutant M. pneumoniae, and 56.44% (57/101) of the latter contained the mutations at low frequency (≤50%).

Conclusion

ASPCR indicated that sensitive and resistant quasispecies coexisted in most of the M. pneumoniae positive samples. The ASPCR was a highly sensitive, accurate and rapid method for detecting the macrolide resistance-associated mutations and it could provide earlier and more drug-resistant information for M. pneumoniae research and the clinical therapy.

In vitro susceptibility test of Xiao'er Feire Kechuan Oral Solution to Mycoplasma pneumoniae

The aim of this study was to evaluate the inhibitory effect of antibiotics and Xiao'er Feire Kechuan Oral Solution on Mycoplasma pneumoniae (MP) clinical isolates.Twenty clinical isolates containing A-to-G transition at position 2063 and 10 clinical isolates without mutations in 23S rRNA V regions were randomly selected. The international standard strain FH was chosen as control strain. The minimum inhibitory concentration (MIC) of macrolide, quinolones, tetracycline, and Xiao'er Feire Kechuan Oral Solution to MP clinical isolates were performed using broth microdilution method.In vitro antibiotic susceptibility test of MP clinical isolates showed that MP showed high resistance to macrolide antibiotics (erythromycin and azithromycin); MIC of both were more than 64 μg/mL. The MICs of erythromycin and azithromycin for clinical isolates without mutations in 23S rRNA V regions were ≤0.5 μg/mL. The MICs of tetracycline and levofloxacin for all clinical isolated strains were ≤2.0 μg/mL and ≤1.0 μg/mL, respectively. The MIC of Xiao'er Feire Kechuan Oral Solution was 13.828∼6.914 mg/mL.In vitro, the drug resistance of MP to macrolide antibiotics is higher, MP clinical isolates are sensitive to tetracycline and levofloxacin, and Xiao'er Feire Kechuan Oral Solution also has a certain inhibitory effect on the macrolide-resistant MP.

[Resistance mechanism of programmed death-1 antibody]

Accompanied with more elaborate and deeper exploration, immunotherapy has been considered one of the most important therapeutic manners for tumor treatment besides conventional operative, chemotherapeutic, radiotherapeutic and targeted-therapeutic strategies. The application of programmed death-1 (PD-1) antibody has provided a new therapeutic option for patients and becomes a research focus of immunotherapy field. PD-1 antibody has been permitted to apply to the treatment of different types of cancers such as melanoma. PD-1 has been demonstrated to be highly effective, including the steady tumor growth control, even complete remission acquired. Although the PD-1 antibody displays great therapeutic effectiveness and application prospects, an increasingly number of drug resistant phenomena have also occurred. Little has been known about the mechanisms of PD-1 antibody resistance by now. However, exploring this mechanism, innovating new treatment mode of drug combination, avoiding the occurrence of drug resistance and decreasing the adverse influence of drug resistance, even reversing it, will be useful to guide the adjustment of treatment strategies, continuously improve the effects of immunotherapy, and give patients long-term survival benefit.

Clinical practices s of Traditional Chinese Medicine for acute upper respiratory tract infection in children

OBJECTIVE

To develop Clinical practice s of Traditional Chinese Medicine (TCM) for acute upper respiratory tract infection (AURI) in children; TCM is used alone or administered together with antibiotics.

METHODS

Under the guidance of evidence-based medicine concept, in strict accordance with the rules of international s development, as well as on the basis of evidence of clinical research of TCM, the s solicited opinions from clinical experts and methodologists in TCM and Western Medicine. GRADE standard was applied to form experts' consensus.

RESULTS

The s standardized classification of TCM patterns and TCM treatments in children with AURI, including prescription, Chinese patent medicine, non-drug treatment and prevention.

CONCLUSION

Follows the principle of ""evidence based, consensus supplemented, and experience referred"", these s were formulated, but the quality of evidence of included studies were relatively low. Further refinement of the s should be needed as deeper clinical studies as available in future.

Clinical Course and Factors Associated with Asthma Control in Children under Control-based Asthma Management: A Prospective Study

In the current study, we sought to track the clinical course of children under control-based asthma management and focused on respiratory pathogens monitoring. We prospectively explored influencing factors for asthma control. 121 children with uncontrolled asthma between 3-14 years of age were recruited. Common respiratory pathogens were detected with pharyngeal swabs and serum aeroallergen-specific IgE was measured. Numeric asthma control scores, airway resistance and fractional concentrations of exhaled nitric oxide (FENO) were evaluated. A proper control-based asthma management plan was established by the study physician. Regular reviews were performed, with the above measurements retested at set time intervals. The proportion of patients achieving asthma control at 1 month and 3 months were 59% and 76% ; respectively (p=0.013). These patients exhibited significant improvement in numeric scores and lung function parameters. The prevalence of common respiratory pathogens did not significantly differ between reviews. The number of sensitized aeroallergens significantly increased with age (r=0.235, p=0.010). Children with a high visual analogue scale (VAS) score for asthma at baseline were less likely to achieve asthma control after 1 month, while those sensitized to more aeroallergens were more likely to achieve asthma control after 1 month (p=0.016 and 0.012). In summary, children with asthma showed significant improvements in control rates and lung function during control-based asthma management, independent of respiratory pathogens testing reults. Patients with high VAS scores and fewer sensitizations to aeroallergens had difficulty achieving short-term asthma control.

Knowledge, attitude, and practices (KAP) and risk factors analysis related to cystic echinococcosis among residents in Tibetan communities, Xiahe County, Gansu Province, China

•

A community based cross-sectional study of CE was conducted in Tibetan communities.

•

This is the first knowledge, attitude, and practice (KAP) study of CE in the areas.

•

Most of residents had positive attitude toward treatments of the disease.

•

Their practice about prevention and control of the disease was not so good.

•

Feeding dogs with offal is still one of risk factors of CE transmission.

Cystic echinococcosis (CE) is a global parasitic zoonosis caused by Echinococcus granulosus. The disease is highly endemic in western China, especially in Tibetan areas, because of poor economic development and hygiene conditions, limited community knowledge of CE, a large scale of dogs, and home slaughtering of livestock. Although many researchers have analyzed risk factors of CE transmission in Tibetan Plateau, there are rare reports of knowledge, attitude, and practice (KAP) of residents about CE in Tibetan communities. In our current study, community based cross-sectional study was conducted in three townships in Xiahe County, Gannan Tibetan Autonomous Prefectures of Gansu Province from May to September 2013. A total of 972 participants originating from Tibetan communities of 31 villages in the 3 townships were registered and data were collected using structured questionnaires. From the total of 972 study participants (457 males and 515 females), 65.9% heard of the disease CE. Most of them (96.1%) would like to accept CE inspection. About half of the peoples feed their dogs often and major of them do not play with the dogs. Risk factors included resident, knowing dog could be infected, knowing eating could be route of infection, oldest dog's age, usually feed your dog by self, feed dogs with internal organs. In general our findings showed that most of residents had positive attitude toward treatments of the disease, but their practice about disease prevention and control was low. Therefore, our study called for continued and strengthened education of changing the life style, especially the behaviors related to dogs.

Effects of a proteasome inhibitor on the NF-κB signalling pathway in experimental osteoarthritis

OBJECTIVES

To evaluate the effects of the proteasome inhibitor MG-132 on the expression of nuclear factor (NF)-κB p65, inhibitor (I)-κB, tumour necrosis factor (TNF)-α, and interleukin (IL)-1β in the cartilage and synovial tissues of rats with osteoarthritis (OA), and to investigate the role that the ubiquitin/proteasome system (UPS) plays in the OA process.

METHOD

A total of 144 adult male Sprague Dawley rats were randomly assigned to four groups: anterior cruciate ligament transaction (ACLT) + MG-132 (ACLT/M), ACLT + dimethylsulfoxide (ACLT/D), sham surgery (Sham), and naïve + MG-132 (naïve/M). Pathological morphology was undertaken. mRNA expression levels of NF-κB p65, I-κB, TNF-α, and IL-1β were determined using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The activities of the 20S proteasome chymotrypsin-like and peptidylglutamyl-peptide hydrolase-like enzymes were measured using fluorospectrophotometry.

RESULTS

The Mankin scores at all time points in ACLT/M rats were significantly lower than those in ACLT/D rats (p < 0.05). Despite the NF-κB p65 in the synovial tissue at 2 weeks after surgery and IL-1β in the cartilage tissue at 12 weeks after surgery, mRNA expression levels of NF-κB p65, IL-1β, and TNF-α at other time points in ACLT/M were significantly lower than those in ACLT/D (p < 0.05). mRNA levels of I-κB in the cartilage tissue in ACLT/M were significantly higher than those in ACLT/D at 2 weeks after surgery (p < 0.05). mRNA levels of I-κB in the synovial tissue in ACLT/M were higher than those in ACLT/D at all time points, and the difference was significant at 4 weeks after surgery (p < 0.05). MG-132 decreased the activities of the 20S proteasome chymotrypsin-like and peptidylglutamyl-peptide hydrolase-like enzymes in the cartilage and synovial tissues of rats.

CONCLUSIONS

The proteasome inhibitor MG-132 delays the progress of OA by alleviating synovial inflammation and protecting the articular cartilage tissue.

Phytoestrogens from Psoralea corylifolia reveal estrogen receptor-subtype selectivity

The seed of Psoralea corylifolia L. (PCL), a well-known traditional Chinese medicine, has been applied as a tonic or an aphrodisiac agent and commonly used as a remedy for bone fracture, osteomalacia and osteoporosis in China. In our study, the estrogen receptor subtype-selective activities of the extracts and compounds derived from PCL were analyzed using the HeLa cell assay. The different fractions including petroleum ether, CH(2)Cl(2) and EtOAc fractions of the EtOH extract of PCL showed significant activity in activating either ERalpha or ERbeta whereas the n-BuOH fraction showed no estrogenic activity. Further chromatographic purification of the active fractions yielded seven compounds including the two coumarins isopsoralen and psoralen, the four flavonoids isobavachalcone, bavachin, corylifol A and neobavaisoflavone, and the meroterpene phenol, bakuchiol. In reporter gene assay, the two coumarins (10(-8)-10(-5)M) acted as ERalpha-selective agonists while the other compounds (10(-9)-10(-6)M) activated both ERalpha and ERbeta. The estrogenic activities of all compounds could be completely suppressed by the pure estrogen antagonist, ICI 182,780, suggesting that the compounds exert their activities through ER. Only psoralen and isopsoralen as ERalpha agonists promoted MCF-7 cell proliferation significantly. Although all the compounds have estrogenic activity, they may exert different biological effects. In conclusion, both ER subtype-selective and nonselective activities in compounds derived from PCL suggested that PCL could be a new source for selective estrogen-receptor modulators.

Prognostic significance of Id-1 and its association with EGFR in renal cell cancer

AIMS

Epidermal growth factor receptor (EGFR) is suggested as one of the positive regulators in the invasive progression of renal cell cancer (RCC). Recently, Id-1 (inhibitor of differentiation or DNA binding), a helix-loop-helix transcription factor, has been identified as one of the key factors in the EGFR signalling pathway. The aim of this study was to investigate the significance of Id-1 expression in renal cell cancer and to study its relationship with EGFR.

METHODS AND RESULTS

Id-1 and EGFR expression was examined in tissue microarray (TMA) samples of 107 RCC and 32 normal kidney specimens by immunohistochemistry. Relative Id-1 and EGFR protein expression was quantified by estimating the staining intensity on a four-grade scale. We found that while negative to weak expression of Id-1 and EGFR was observed in non-malignant kidney tissues, most RCCs showed significant positive Id-1 and EGFR expression in tumour cells. In addition, Id-1 immunostaining intensity was positively associated with increased tumour staging, grading and EGFR expression.

CONCLUSION

Overexpression of Id-1 is a novel marker for advanced RCC which is positively correlated with EGFR expression. Our results suggest that Id-1 may play an important role in the development of RCC and indicate that Id-1 is a potential marker of patients with a poor prognosis.

Morphology and physiology of the polyaxonal amacrine cells in the rabbit retina

We examined the morphology and physiological response properties of the axon-bearing, long-range amacrine cells in the rabbit retina. These so-called polyaxonal amacrine cells all displayed two distinct systems of processes: (1) a dendritic field composed of highly branched and relatively thick processes and (2) a more extended, often sparsely branched axonal arbor derived from multiple thin axons emitted from the soma or dendritic branches. However, we distinguished six morphological types of polyaxonal cells based on differences in the fine details of their soma/dendritic/axonal architecture, level of stratification within the inner plexiform layer (IPL), and tracer coupling patterns. These morphological types also showed clear differences in their light-evoked response activity. Three of the polyaxonal amacrine cell types showed on-off responses, whereas the remaining cells showed on-center responses; we did not encounter polyaxonal cells with off-center physiology. Polyaxonal cells respected the on/off sublamination scheme in that on-off cells maintained dendritic/axonal processes in both sublamina a and b of the IPL, whereas processes of on-center cells were restricted to sublamina b. All polyaxonal amacrine cell types displayed large somatic action potentials, but we found no evidence for low-amplitude dendritic spikes that have been reported for other classes of amacrine cell. The center-receptive fields of the polyaxonal cells were comparable to the diameter of their respective dendritic arbors and, thus, were significantly smaller than their extensive axonal fields. This correspondence between receptive and dendritic field size was seen even for cells showing extensive homotypic and/or heterotypic tracer coupling to neighboring neurons. These data suggest that all polyaxonal amacrine cells are polarized functionally into receptive dendritic and transmitting axonal zones.

Suppression subtractive hybridization for identifying differentially expressed genes in renal cell carcinoma

OBJECTIVE

To construct a renal cell carcinoma (RCC) cDNA subtractive library using suppression subtractive hybridization.

METHODS

Polyadenylated RNA [Poly (A)+ RNA] was isolated from tissues of RCC and normal kidney, and single-strand cDNAs and double-strand cDNAs were synthesized in turn. RCC cDNAs were divided into two groups and ligated to the specific adaptors I and 2, and then hybridized with normal kidney cDNA twice with two rounds of suppression PCR. Second round PCR products were cloned to T/A plasmid vectors to set up the subtractive library. One hundred clones were randomly picked to perform enzyme digest analysis, and some underwent sequence analysis and Northern blot to identify RCC specifically expressed genes. SMART RACE procedure was operated to clone full length novel RCC specifically expressed genes.

RESULTS

A human RCC subtractive library with high subtractive efficiency was successfully set up. The amplified library contains 350 positive clones. Random analysis of 100 clones with enzyme restriction showed that 85 plasmids in the clones contained 50-400 bp inserts. Sequence analysis was performed for 10 clones. All the 10 sequences were unknown before and derived from 6 unique, novel genes among which the cDNA insert RCC18 had five copies. Northern blot analysis showed that RCC18 cDNA was highly expressed in RCC, but no signal could be detected in normal kidney. Using SMART RACE technique, we obtained the full length of the novel gene RCC18.

CONCLUSIONS

The constructed cDNA subtractive library of human RCC is a highly efficient one and lays a solid foundation for large scale screening and cloning new and specific oncogenes or tumor suppressor genes of RCC. The novel specifically expressed genes provided an important clue for studying the mechanisms of occurrence and development of RCC.

[Frequent somatic mutations of the von Hippel-Lindau tumor suppressor gene in primary sporadic human renal clear cell carcinomas]

OBJECTIVE

To investigate the mutation of Von Hippel-Lndau (VHL) tumor suppressor gene in patients with primary sporadic human renal cell carcinoma (RCC).

METHODS

DNA samples from 20 primary sporadic renal clear carcinoma patients were analyzed by polymerase chain reaction, single strand conformational polymorphism analyses (PCR-SSCP) and direct sequencing.

RESULTS

Somatic mutations of the VHL gene were detected in 11 (55%) of the 20 clear cell renal carcinomas, including 6 deletions, 2 insertions, and 3 missense mutations. These mutations mainly occurred in the last one-third region of exon 1, 2 and 3 of the VHL gene.

CONCLUSION

The VHL gene may frequently mutate in Chinese patients with primary sporadic renal clear cell carcinoma. The VHL gene may be useful as a marker gene for the diagnosis of RCC and as a target gene for molecular therapy.

Expression of beta-catenin in renal cell carcinoma

OBJECTIVE

To investigate the expression of beta-catenin and its mRNA in renal cell carcinoma.

METHODS

Twenty-six cases with renal cell carcinoma (RCC) were studied by immunohistochemistry, Western blot and RT-PCR.

RESULTS

We found the expression of beta-catenis is higher in cancer tissues than in normal kidney tissues and the level of beta-catenin is associated with the tumor stage. Its expression in tumor of pT3 and pT4 is obviously higher than pT1 and pT2 (P < 0.01). That is to say, there was an overexpression of beta-catenin protein in RCC and its level was related to the tumor stage, but the expression of beta-catenin mRNA had no difference between tumor tissue and normal tissue.

CONCLUSION

beta-catenin may be related to the occurrence and progress of RCC.

[Cloning and identifying of renal cell carcinoma differentially expressed genes]

OBJECTIVE

To clone and identify RCC specially expressed genes different with normal kidney tissue.

METHODS

A technique called suppression subtractive hybridization was used to construct the library which contains the differently expressing cDNAs between RCC and normal kidney. Then the RCC specially expressed genes were cloned from it.

RESULTS

Human RCC subtractive library with high subtractive efficiency was set up successfully. The amplified library contains 350 positive clones. Sequence analysis was performed in 5 clones. All of the sequences were unknown before and the cDNA inserting GYLZ-RCC18 had three copies. Northern blot analysis showed that GYLZ-RCC18 cDNA expressed highly in RCC, but there was no any signal could be detected in normal kidney. Using SMART RACE technique, we obtained the full length of novel gene of GYLZ-RCC18. We also identified that GYLZ-RCC18 family contains 3 subtype genes.

CONCLUSIONS

The highly efficient cDNA subtractive library lays a solid foundation for screening and cloning new and specific oncogenes or tumor suppressor genes of RCC. The novel differentially expressed genes provide an important clue to studying the mechanism of the occurrence and development of RCC.

Effects of nitric oxide on horizontal cells in the rabbit retina

Retinal horizontal cells display large receptive fields as a result of extensive electrical coupling via gap junctions. There is abundant evidence that these gap junctions are dynamically regulated by changes in the adaptational state of the retina. The neuromodulator dopamine appears to play a major role in regulating gap junctional conductances of horizontal cells. Emerging evidence indicates that nitric oxide (NO) also acts as a neuromodulator in the retina and, more specifically, regulates the coupling between horizontal cells. In the present study, we examined the effects of a nitric oxide, and its secondary messenger cGMP, on electrical and tracer coupling between A-type and between B-type horizontal cells in the rabbit retina. Application of the NO donors S-nitroso-N-acetylpenicillamine (SNAP) or sodium nitroprusside (SNP) significantly reduced the coupling between horizontal cells as evidenced by a decrease in their space constants, annulus-to-small spot response ratios, and the extent of tracer coupling following injection with Neurobiotin. Further, application of SNP eliminated the increase in coupling of horizontal cells normally seen with exposure to dim background illumination. Application of 8-bromo-cGMP produced effects similar to those of the NO donors, consistent with the idea that the uncoupling actions of NO were mediated via a cGMP cascade. In addition, the NO donors and cGMP augmented the responsiveness of A- and B-type cells to both small and large spots of light. This augmentation appeared to be due to secondary effects on photoreceptor transduction and/or photoreceptor-to-horizontal cell synaptic efficacy that were distinct from the actions on gap junctions. Our results suggest that NO may mediate changes in coupling between horizontal cells related to the adaptational state of the mammalian retina.

Different Wnt-5A gene expressions in the renal cell carcinoma GRC-1 cell line during the cell cycle

OBJECTIVE

To investigate the gene expression at transcription level of growth factor Wnt-5A in different phase during the cell cycle.

METHODS

We synchronized the renal cell carcinoma GRC-1 cell line by double thymidine blocks and high-pressure N2O gae methods and amplified Wnt-5A cDNAs from different phase using Semi-quantitative RT-PCR (reverse transcriptase polymerase chain reaction). The PCR products were electrophoresized on the agrose gel and detected by Gel Doc 1000 computer controlled system integrating the volumes of each band, representing the intensities of all pixels in a defined band.

RESULTS

The different mRNA expressions of growth factor Wnt-5A was detected in RCC GRC-1 cell line. In S phase, the highest level of Wnt-5A transcript was observed, and in G1 and M phase, medial and lowest, respectively. The differences between S and M stages were statistically significant (P < 0.05).

CONCLUSION

Growth factor Wnt-5A has the potential effect on tumorigenesis. It contributes to all phases during cell cycle but in S phase especially.

Surround inhibition of mammalian AII amacrine cells is generated in the proximal retina

1. Intracellular recordings were obtained from neurons in the superfused retina-eyecup preparation of the rabbit under dark-adapted conditions. Neurotransmitter agonists and antagonists were applied exogenously via the superfusate to dissect the synaptic pathways pharmacologically and thereby determine those pathways responsible for the generation of the on-centre/off-surround receptive fields of AII amacrine cells. 2. Application of the metabotropic glutamate receptor agonist, APB, reversibly blocked both the on-centre and off-surround responses of AII cells. These data were consistent with the idea that both the centre- and surround-mediated responses are derived from inputs from the presynaptic rod bipolar cells. 3. Whereas rod bipolar cells showed on-receptive fields approximately 100 microm across, we found no evidence for an antagonistic off-surround response using light stimuli which effectively elicited the off-surrounds of AII amacrine cells. These results indicated that the surrounds of AII cells are not derived from rod bipolar cell inputs. 4. Application of the ionotropic glutamate receptor antagonists CNQX or DNQX enhanced the on-centre responses of AII cells but attenuated the off-surround responses. These data indicated that the centre- and surround-mediated responses could not both be derived from signals crossing the rod bipolar-to-AII cell synapse. 5. Application of the glycine antagonist, strychnine, had only minor and variable effects on AII cell responses. However, the GABA antagonists picrotoxin and bicuculline enhanced the on-centre response but attenuated or completely blocked the off-surround response of AII cells. The GABA antagonists had no effect on the responses of horizontal cells indicating that their effects on AII cell responses reflected actions on inner retinal circuitry rather than feedback circuitry in the outer plexiform layer. 6. Application of the voltage-gated sodium channel blocker TTX enhanced the on-centre responses of AII cells but attenuated or abolished their off-surround responses. 7. Taken together, our results suggest that the on-centre responses of AII cells result from the major excitatory drive from rod bipolar cells. However, the surround receptive fields of AII cells appear to be generated by lateral, inhibitory signals derived from neighbouring GABAergic, on-centre amacrine cells. A model is presented whereby the S1 amacrine cells produce the surround receptive fields of AII amacrine cells via inhibitory, feedback circuitry to the axon terminals of rod bipolar cells.

[Beta-catenin and its mRNA in renal cell carcinoma]

OBJECTIVES

To investigate the role of beta-catenin in renal cell carcinoma.

METHODS

The expression of beta-catenin in 26 cases of renal cell carcinoma was studied by LSAB immunohistochemistry, Western blotting and RT-PCR.

RESULTS

The expression of beta-catenin was higher in cancer tissues than in normal kidney tissues in 25 cases and the level of beta-catenin was associated with tumor stage. The expression was obviously higher in pT3 and pT4 than in pT1 and pT2 (P < 0.01). The expression of its mRNA was not higher in tumor cells than in normal cells. Beta-catenin was expressed mainly in cytoplasm.

CONCLUSIONS

Beta-catenin might be related to the occurrence and development of kidney tumor.

Cloning and sequencing of the rat cDNAs encoding class I beta-tubulin

Two kinds of rat cDNA clones encoding class I beta-tubulin were isolated from the neonatal rat brain, and sequenced. They corresponded to mRNA species formed by the alternative usage of polyadenylation signals. The determined nucleotide sequence showed high (84.6%) identity to rat class II beta-tubulin, the only rat beta-tubulin sequence reported in the nucleotide database, in the coding region, but relatively low (47.3-50.7%) in the noncoding region. The Northern blot analysis using the 3'-noncoding fragment as a probe showed that both mRNA species of the class I beta-tubulin were down-regulated during brain development.

Comparison of the responses of AII amacrine cells in the dark- and light-adapted rabbit retina

We studied the light-evoked responses of AII amacrine cells in the rabbit retina under dark- and light-adapted conditions. In contrast to the results of previous studies, we found that AII cells display robust responses to light over a 6-7 log unit intensity range, well beyond the operating range of rod photoreceptors. Under dark adaptation, AII cells showed an ON-center/OFF-surround receptive-field organization. The intensity-response profile of the center-mediated response component followed a dual-limbed sigmoidal function indicating a transition from rod to cone mediation as stimulus intensities were increased. Following light adaptation, the receptive-field organization of AII cells changed dramatically. Light-adapted AII cells showed both ON- and OFF-responses to stimulation of the center receptive field, but we found no evidence for an antagonistic surround. Interestingly, the OFF-center response appeared first following rapid light adaptation and was then replaced gradually over a 1-4 min period by the emerging ON-center response component. Application of the metabotropic glutamate receptor agonist APB, the ionotropic glutamate blocker CNQX, 8-bromo-cGMP, and the nitric oxide donor SNAP all showed differential effects on the various center-mediated responses displayed by dark- and light-adapted AII cells. Taken together, these pharmacological results indicated that different synaptic circuits are responsible for the generation of the different AII cell responses. Specifically, the rod-driven ON-center responses are apparently derived from rod bipolar cell synaptic inputs, whereas the cone-driven ON-center responses arise from signals crossing the gap junctions between AII cells and ON-center cone bipolar cells. Additionally, the OFF-center response of light-adapted AII cells reflects direct synaptic inputs from OFF-center cone bipolar cells to AII dendritic processes in the distal inner plexiform layer.

Dark- and light-induced changes in coupling between horizontal cells in mammalian retina

Retinal horizontal cells exhibit large receptive fields derived from their extensive electrical coupling by means of gap junctions. The conductance of these gap junctions seems to be regulated by dopamine acting through a cAMP-mediated cascade. There is now abundant evidence that extracellular dopamine levels vary with changes in ambient light intensity, suggesting that changes in the dark/light adaptational state of the retina can modulate coupling between horizontal cells. We studied this question in the mammalian retina by determining the effects of ambient light levels, in the form of changing background light intensity, on the coupling profiles of A- and B-type horizontal cells in the rabbit. Changes in coupling were assessed by measurements of the space constants of the syncytium formed by horizontal cells and the intercellular spread of the biotinylated tracer Neurobiotin. Our results indicate that dark-adapted horizontal cells show relatively weak coupling. However, presentation of background lights as dim as one-quarter log unit above rod threshold resulted in increases in both the averaged extent of tracer coupling and space constants of A- and B-type horizontal cells. Coupling expanded further as background light intensities were increased by 1-1.5 log units, after which additional light adaptation brought about an uncoupling of cells. Coupling reached its minimum at light intensities about 3 log units above rod threshold, after which, with further light adaptation, it stabilized at levels close to those seen in dark-adapted retinas. Our results indicate that electrical coupling between mammalian horizontal cells is modulated dramatically by changes in the adaptational state of the retina: coupling is maximized under dim ambient light conditions and diminishes as the retina is dark or light adapted from this level.

Effect of verbascoside on decreasing concentration of oxygen free radicals and lipid peroxidation in skeletal muscle

AIM

To detect the effects of verbascoside on decreasing the concentration of oxygen free radicals (OFR) and lipid peroxidation in skeletal muscle resulting from exhaustive exercise.

METHODS

Electron spin resonance (ESR) technique and thiobarbituric acid reaction (TBAR) method were used to detect the concentration of OFR in intact gastrocnemius muscle and the contents of milondialdehyde (MDA) in muscle homogenate.

RESULTS

Verbascoside decreased the concentration of OFR (P < 0.05) and the level of lipid peroxidation (P < 0.05) in muscle caused by exercise.

CONCLUSION

Verbascoside has the effects of reducing oxidative stress in muscle caused by exhaustive exercise by decreasing the concentration of free radicals and the level of lipid peroxidation.

[Investigation of factors affecting the development of COPD]

OBJECTIVE

To investigate the factors which affect the development of COPD.

METHODS

88 patients with mPAP less than 20 mm Hg were followed up by 5 - 20 years. Pulmonary ventilation, blood gas analysis, ECG, pulmonary hemodynamic parameters and oxygen saturation at night were performed one time every 5 years.

RESULTS

The results showed that: 5 year, 10 year and 20 year's mortality is 6%, 25% and 43% respectively; MVV%, FEV(1)% and PaO(2) declined accompanied by the increase of PaCO(2); among 41 patients with mPAP 16 - 20 mm Hg, 20 patients' mPAP were more than 20 mm Hg and 15 patients died after 10 years' follow up. Among 16 patients with the declination of oxygen saturation, 8 patients' mPAP were more than 20 mm Hg and 6 patients died. 57 strains of infectious bacteria were found in 88 patients' sputum with 43 strains in the death group.

CONCLUSIONS

These results demonstrated that COPD is a kind of chronic diseases with high death rate; infection, decline of oxygen saturation at night and mPAP more than 16 mm Hg were high risk factors in COPD.

Mitochondrial DNA in platelets from aged subjects

This study aimed to assess platelets as a possible model for screening the accumulation of mitochondrial DNA mutations, particularly during normal ageing. For this purpose we isolated platelets from young and old donors selected by lack of systemic and haematological diseases. We studied the accumulation of a particular deletion (4977-bp deletion) that usually accumulates in an age-related manner in different post-mitotic tissues, such as brain, heart and skeletal muscle, and in some non-post-mitotic tissues (skin, liver). Using different primers, we failed to detect this particular species of deletion in platelets both from young and old individuals. However, we cannot exclude the presence of other species of deletions or point mutations affecting the mitochondrial DNA in platelets during the aging process.

A comparison of receptive-field and tracer-coupling size of amacrine and ganglion cells in the rabbit retina

Recent studies have shown that amacrine and ganglion cells in the mammalian retina are extensively coupled as revealed by the intercellular movement of the biotinylated tracers biocytin and Neurobiotin. These demonstrations of tracer coupling suggest that electrical networks formed by proximal neurons (i.e. amacrine and ganglion cells) may underlie the lateral propagation of signals across the inner retina. We studied this question by comparing the receptive-field size, dendritic-field size, and extent of tracer coupling of amacrine and ganglion cells in the dark-adapted, superfused, isolated retina eyecup of the rabbit. Our results indicate that while the center-receptive fields of proximal neurons are approximately 15% larger than their corresponding dendritic diameters, this slight difference can be explained by factors other than electrical coupling such as tissue shrinkage associated with histological processing. However, the extent of tracer coupling of amacrine and ganglion cells was, on average, about twice the size of the corresponding receptive fields. Thus, the receptive field of an individual proximal neuron matched far more closely to its dendritic diameter than to the size of the tracer-coupled network of cells to which it belonged. The exception to this rule was the AII amacrine cells for which center-receptive fields were 2-3 times the size of their dendritic diameters but matched closely to the size of the tracer-coupled arrays. Thus, with the exception of AII cells, our data indicate that tracer coupling between proximal neurons is not associated with an enlargement of their receptive fields. Our results, then, provide no evidence for electrical coupling or, at least, indicate that extensive lateral spread of visual signals does not occur in the proximal mammalian retina.

[Role of pulmonary arterial angiotensin converting enzyme in development of hypoxic pulmonary hypertension]

OBJECTIVE

To study the effect of local pulmonary arterial renin-angiotensin system on hypoxic pulmonary hypertension(PAH).

METHOD

Normobaric hypoxic PAH animal model was adopted. Systolic pulmonary arterial pressure(PAPs), pulmonary arterial angiotensin converting enzyme(ACE) activity, collagen content(HP) were measured and ultrastructure of pulmonary smooth muscle cells (SMC) and was observed.

RESULTS

During hypoxia, PAPs, pulmonary ACE activity, HP increased significantly and SMC changed into secretive phenotype. Treatment with cilazapril, an ACE inhibitor, decreased ACE activity along with reversal of PAPs. HP and SMC phenotype.

CONCLUSIONS

Pulmonary ACE participated in the modulation of changes of SMC phenotype and collagen metabolism during hypoxic PAH.

Tracer coupling pattern of amacrine and ganglion cells in the rabbit retina

We examined the tracer coupling pattern of more than 15 morphological types of amacrine and ganglion cells in the rabbit retina. Individual cells were injected intracellularly with the biotinylated tracer Neurobiotin, which was then allowed to diffuse across gap junctions to label neighboring neurons. We found that homologous and/or heterologous tracer coupling was common for most proximal neurons. In fact, the starburst amacrine cell was the only amacrine cell type that showed no evidence of coupling. The remaining types of amacrine cell were coupled exclusively to other amacrines, either homologously or, more often, through a combination of homologous and heterologous junctions. In only one case did we visualize labeled ganglion cells following injection of Neurobiotin into an amacrine cell. In contrast, injection of Neurobiotin into ganglion cells almost always resulted in the labeling of amacrine cells. Taken together, these results suggest a directionality to the movement of tracer across gap junctions connecting amacrine and ganglion cells. We found that the coupling pattern for a given morphological type of cell was generally stereotypic and consistent across retinas. The notable exceptions to this finding were alpha ganglion cells and cells with morphology corresponding to that of on-off direction selective ganglion cells. In both cases, individual cells showed either extensive coupling to both amacrine and ganglion cells or no coupling at all. A notable finding was that, in every case, the neighboring cells within a tracer-coupled array were always within one gap junction of the injected neuron. Furthermore, in many cases, the array formed by the somata of tracer-coupled cells was almost perfectly coincident with the dendritic arbor of the injected cell. Thus, our results indicate that whereas coupling is extensive within the proximal retina, individual cells partake in coupled networks that are stereotypic and highly circumscribed.

Light-induced modulation of coupling between AII amacrine cells in the rabbit retina

The rod-driven, AII amacrine cells in the mammalian retina maintain homologous gap junctions with one another as well as heterologous gap junctions with on-cone bipolar cells. We used background illumination to study whether changes in the adaptational state of the retina affected the permeabilities of these two sets of gap junctions. To access changes in permeability, we injected single AII amacrine cells with the biotinylated tracer, Neurobiotin, and measured the extent of tracer coupling to neighboring AII cells and neighboring cone bipolar cells. We also measured the center-receptive field size of AII cells to assess concomitant changes in electrical coupling. Our results indicate that in well dark-adapted retinas, AII cells form relatively small networks averaging 20 amacrine cells and covering about 75 microns. The size of these networks matched closely to the size of AII cell on-center receptive fields. However, over most of their operating range, AII cells formed dramatically larger networks, averaging 326 amacrine cells, which corresponded to an increased receptive-field size. As the retina was light adapted beyond the operating range of the AII cells, they uncoupled to form networks comparable in size to those seem in well dark-adapted retinas. Our results, then, indicate that the adaptational state of the retina has a profound effect on the extent of electrical coupling between AII amacrine cells. Although we observed light-induced changes in the number of tracer-coupled cone bipolar cells, these appeared to be an epiphenomenon of changes in homologous coupling between AII amacrine cells. Therefore, in contrast to the robust changes in AII-AII coupling produced by background illumination, our data provided no evidence of a light-induced modulation of coupling between AII cells and on-cone bipolar cells.

[The significance of circulating endothelial cell in hypoxic injury of pulmonary vascular endothelial cell]

OBJECTIVE

To observe the changes of vascular endothelial cell (VEC) in hypoxic rats and to check the damage of VEC in vivo, an experiment for observing circulating endothelial cells was conducted.

METHOD

Thirty male Wistar rats were classified into 5 groups in random, exposted to 10% O2 and 1% FeCl3 intraveniously. After 0, 1, 2, 3, 4 weeks, PaO2, circulating endothelial cells (CEC) were measured and the lung specimens, the pulmonary artery were examined by transmission electron micrography (TEM) and scanning electron micrography (SEM).

RESULTS

Lung specimens and pulmonary artery under TEM and SEM: swollen appeared to VEC after 1 week. As time prolonged, VEC appeared splitting, broken and peeled off. The amount of CEC increased as the time proceeding, the longer the time, the higher the number of the CEC. Obvious hypoxemia developed in the tested animals as the time prolonged.

CONCLUSIONS

All above results indicated: the time of anoxia proceeding, the structure of lung and pulmonary artery VEC were damaged obviously. The increase of CEC matched with the changes of ultrastructure of lung VEC. CEC specifically reflected the damage of VEC. Non-invasive measurement of CEC is valuble in evaluation of hypoxic injury of pulmonary VEC.

A comparison of receptive field and tracer coupling size of horizontal cells in the rabbit retina

The large receptive fields of retinal horizontal cells are thought to reflect extensive electrical coupling via gap junctions. It was shown recently that the biotinylated tracers, biocytin and Neurobiotin, provide remarkable images of coupling between many types of retinal neuron, including horizontal cells. Further, these demonstrations of tracer coupling between horizontal cells rivaled the size of their receptive fields, suggesting that the pattern of tracer coupling may provide some index of the extent of electrical coupling. We studied this question by comparing the receptive field and tracer coupling size of dark-adapted horizontal cells recorded in the superfused, isolated retina-eyecup of the rabbit. Both the edge-to-edge receptive field and space constants (lambda) were computed for each cell using a long, narrow slit of light displaced across the retinal surface. Cells were subsequently labeled by iontophoretic injection of Neurobiotin. The axonless A-type horizontal cells showed extensive, homologous tracer coupling in groups greater than 1000 covering distances averaging about 2 mm. The axon-bearing B-type horizontal cells were less extensively tracer coupled, showing homologous coupling of the somatic endings in groups of about 100 cells spanning approximately 400 microns and a separate homologous coupling of the axon terminal endings covering only about 275 microns. Moreover, we observed a remarkable, linear relationship between the size of the receptive fields of each of the three horizontal cell endings and the magnitude of their tracer coupling. Our findings suggest that the extent of tracer coupling provides a strong, linear index of the magnitude of electrical current flow, as derived from receptive-field measures, across groups of coupled horizontal cells. These data thus provide the first direct evidence that the receptive-field size of horizontal cells is related to the extent of their coupling via gap junctions.

Visual evoked potentials following abrupt contrast changes

The timing of visual evoked potential (VEP) amplitude and phase changes following abrupt increases or decreases in contrast was examined. Gratings (1 c/deg) were presented at a low contrast for 8 sec, increased to a higher contrast for 8 sec, and then decreased to the initial lower contrast for another 8 sec. Second harmonic VEP amplitude and phase were recorded continuously and averaged in 1 sec epochs. Both amplitude and phase exhibited delays in reaching a stable level following the contrast change. For amplitude, the length of the delay was dependent on the magnitude and direction of the contrast step and on the spatial frequency of the stimulus. Time constants for the change in amplitude following step increases in contrast ranged from 0.2 sec for a 12% contrast step to 1.34 sec for a 37% contrast step. The timing of phase changes, however, was independent of the size of the contrast increases (tau = 0.7 sec). For step decreases in contrast, both amplitude and phase were relatively independent of the size of the change (tau = approx. 0.9 sec for amplitude and tau = 0.15 sec for phase). Amplitude time constants also increased with increasing spatial frequency (tau = 1.2 sec for 1 c/deg, tau = 1.6 sec for 4 c/deg and tau = 2.3 sec for 8 c/deg); phase time constants, however, did not change as a function of spatial frequency (tau = 0.7 for all spatial frequencies). These findings demonstrate that a unitary process may not always be tapped by signal averaging techniques. Additionally, swept stimulus VEP techniques may produce considerable errors in threshold estimation depending on the stimulus spatial frequency and on the slope and direction of the contrast change.

[The visual evoked potentials in ischemic optic neuropathy]

In this study the pattern-reversal stimulation was used for analysing the clinical VEP in 27 cases (37 eyes) of ischemic optic neuropathy (ION), and combined uses of visual field (VF) and contrast sensitivity (CS) examinations were compared and observed with 3 kinds of spatial frequencies (60', 30', 15' check size), VEP in the eyes of ION displayed decrease in amplitude as a dominant manifestation accompanied by the slight increase of latency period. The abnormal latency and amplitude were 83.5% and 81.3% respectively. The decreased CS in the ION eyes was appeared mainly in the stimulation of middle and high frequencies or all frequency bands. There was a significant correlation between the VEP amplitude and CS in the patients with ION. The quadrant VF defect and bow-shaped scotoma were displayed in majority of the cases. Abnormal VEP was shown to be related to the central VF impaired. Among these patients, 7 cases (8 eyes) were followed up with VEP, however the VEP amplitude was shown decreasing somewhat compared with first exam. The results indicated that the ION was responsible for many visual function damages.

Clinical application of microcomputer to visual function examination

Microcomputer technique is put into use in ophthalmological clinical visual function examination. In visual EOG, ENG, visual tracking, contrast sensitivity and VEP examination, objectifying and standardization of experiment and data analysis are achieved by computer technique. In addition, a lot of manpower and time is saved, test results are obtained faster and more accurately. The basic rational of computerization in clinical visual function examination is presented.