Cardioprotective Potential of Cymbopogon citratus Essential Oil against Isoproterenol-induced Cardiomyocyte Hypertrophy: Possible Involvement of NLRP3 Inflammasome and Oxidative Phosphorylation Complex Subunits

OBJECTIVE

Cymbopogon citratus (DC.) Stapf is a medicinal and edible herb that is widely used for the treatment of gastric, nervous and hypertensive disorders. In this study, we investigated the cardioprotective effects and mechanisms of the essential oil, the main active ingredient of Cymbopogon citratus, on isoproterenol (ISO)-induced cardiomyocyte hypertrophy.

METHODS

The compositions of Cymbopogon citratus essential oil (CCEO) were determined by gas chromatography-mass spectrometry. Cardiomyocytes were pretreated with 16.9 µg/L CCEO for 1 h followed by 10 µmol/L ISO for 24 h. Cardiac hypertrophy-related indicators and NLRP3 inflammasome expression were evaluated. Subsequently, transcriptome sequencing (RNA-seq) and target verification were used to further explore the underlying mechanism.

RESULTS

Our results showed that the CCEO mainly included citronellal (45.66%), geraniol (23.32%), and citronellol (10.37%). CCEO inhibited ISO-induced increases in cell surface area and protein content, as well as the upregulation of fetal gene expression. Moreover, CCEO inhibited ISO-induced NLRP3 inflammasome expression, as evidenced by decreased lactate dehydrogenase content and downregulated mRNA levels of NLRP3, ASC, CASP1, GSDMD, and IL-1β, as well as reduced protein levels of NLRP3, ASC, pro-caspase-1, caspase-1 (p20), GSDMD-FL, GSDMD-N, and pro-IL-1β. The RNA-seq results showed that CCEO inhibited the increase in the mRNA levels of 26 oxidative phosphorylation complex subunits in ISO-treated cardiomyocytes. Our further experiments confirmed that CCEO suppressed ISO-induced upregulation of mt-Nd1, Sdhd, mt-Cytb, Uqcrq, and mt-Atp6 but had no obvious effects on mt-Col expression.

CONCLUSION

CCEO inhibits ISO-induced cardiomyocyte hypertrophy through the suppression of NLRP3 inflammasome expression and the regulation of several oxidative phosphorylation complex subunits.

[The cases of tracing the source of patients infected with Omicron variant of SARS-CoV-2 based on wastewater-based epidemiology in Shenzhen]

Wastewater-based epidemiology (WBE) is an emerging discipline, which has been applied to drug abuse tracking and infectious disease pathogen surveillance. During the COVID-19 epidemic, WBE has been applied to monitor the epidemic trend and SARS-CoV-2 variants etc. In order to detect hidden COVID-19 cases and prevent transmission in the community, wastewater surveillance system for monitoring SARS-CoV-2 RNA was developed in Shenzhen. The sewage sampling sites were set up in key places such as the port areas, urban villages and residential communities of Futian, Nanshan, Luohu and Yantian districts. From July 26 to November 30, 2022, a total of 369 sewage sampling sites were set up, covering 1.93 million people. Continuous sampling was carried out for 3 hours in the peak period of water use every day. Sewage virus enrichment and SARS-CoV-2 nucleic acid detection were carried out by polyethylene glycol precipitation method and RT-qPCR, and a positive water sample disposal process was molded. This article aims to introduce the case of source tracing of COVID-19 infected patients based on urban sewage in Shenzhen. The sewage monitoring of Honghu water treatment plant in Luohu District played an early warning role, and the source of infection was traced. In the disposal of positive water samples in Futian South Road, Futian District, the important experience of monitoring point layout was obtained. In the sewage monitoring of Nanshan village, Nanshan District, the existence of occult infection was revealed. Sharing the experience of tracing the source of COVID-19 patients to avoid the spread of COVID-19 in the community based on wastewater surveillance of SARS-CoV-2 RNA in Shenzhen, and summarizing the advantages and application prospects of sewage surveillance can provide new ideas for monitoring emerging or re-emerging pathogens that are known to exhibit gastrointestinal excretion in the future.

[Predictive factors for sequelae of bronchitis obliterans in refractory Mycoplasma pneumoniae pneumonia]

Objective: To investigate the predictive factors for bronchitis obliterans in refractory Mycoplasma pneumoniae pneumonia (RMPP). Methods: A restrospective case summary was conducted 230 patients with RMPP admitted to the Department of No.2 Respiratory Medicine of Beijing Children's Hospital, Capital Medical University from January 2013 to June 2017 were recruited. Clinical data, laboratory results, imaging results and follow-up data were collected. Based on bronchoscopy and imaging findings 1 year after discharge, all patients were divided into two groups: one group had sequelae of bronchitis obliterans (sequelae group) and the other group had not bronchitis obliterans (control group), independent sample t-test and nonparametric test were used to compare the differences in clinical features between the two groups. Receiver operating characteristic (ROC) curve to explore the predictive value of Bronchitis Obliterans in RMPP. Results: Among 230 RMPP children, there were 115 males and 115 females, 95 cases had sequelae group, the age of disease onset was (7.1±2.8) years;135 cases had control group, the age of disease onset was (6.8±2.7) years. The duration of fever, C-reative protein (CRP) and lactate dehydrogenase (LDH) levels, the proportion of ≥2/3 lobe consolidation, pleural effusion and the proportion of airway mucus plug and mucosal necrosis were longer or higher in the sequelae group than those in the control group ((17±9) vs. (12±3) d, (193±59) vs. (98±42) mg/L,730 (660, 814) vs. 486 (452, 522) U/L, 89 cases (93.7%) vs. 73 cases (54.1%), 73 cases (76.8%) vs.59 cases (43.7%), 81 cases (85.3%) vs. 20 cases (14.8%), 67 cases (70.5%) vs. 9 cases (6.7%), t=5.76, 13.35, Z=-6.41, χ²=14.64, 25.04, 22.85, 102.78, all P<0.001). Multivariate Logistic regression analysis showed that the duration of fever ≥10 days (OR=1.200, 95%CI 1.014-1.419), CRP levels increased (OR=1.033, 95%CI 1.022-1.044) and LDH levels increased (OR=1.001, 95%CI 1.000-1.003) were the risk factors for sequelae of bronchitis obliterans in RMPP. ROC curve analysis showed that CRP 137 mg/L had a sensitivity of 82.1% and a specificity of 80.1%; LDH 471 U/L had a sensitivity of 62.7% and a specificity of 60.3% for predicting the development of bronchitis obliterans. Conclusions: The long duration of fever (≥10 d), CRP increase (≥137 mg/L) may be used to predict the occurrence of sequelae of bronchitis obliterans in RMPP. It is helpful for early recognition of risk children.

[Effects of Porphyromonas gingivalis injected through tail vein on the expressions of biomarkers in neural stem cells and neurons of wild-type rats hippocampus]

Objectives: To study the effects of Porphyromonas gingivalis (Pg) injected through tail vein on the molecular expression levels of biomarkers of neural stem cells (NSC) and neurons in the hippocampus of wild-type adult rats, and the effects on hippocampal neurogenesis. Methods: Eighteen male Sprague-Dawley (SD) rats were randomly divided into 3 groups based on the table of random numbers (n=6 in each group). In low-intensity group and high-intensity group, rats were injected intravenously through tail vein with 200 μl Pg ATCC33277 [1.0×10³ and 1.0×10⁸ colony forming unit (CFU), respectively] 3 times per week for 8 weeks. In the sham group, 200 μl of phosphate buffer saline (PBS) was given instead. Behavioral tests: the navigation and the exploration tests using Morris water maze (MWM) were applied to evaluate learning and memory ability of rats. Immunohistochemistry was performed to detect cells positively expressing nestin, doublecortin (DCX) and neuronal nuclei (NeuN) in the subgranular zone (SGZ) of rats in each group. Western blotting was used to evaluate the expression levels of nestin, DCX and NeuN in rat hippocampus. Results: Learning and memory abilities: on day 5 of navigation test, the lagency time was 22.83 (16.00, 38.34) s in the high-intensity group, significantly longer than the sham group [5.59 (5.41, 6.17) s] (t=-11.17, P<0.001). There were no significant differences between the low-intensity group [9.85 (8.75, 21.01) s] and the sham group (t=-6.83, P=0.080). Results in the exploration test showed that, in the high-intensity group, the number of fime crossing over the previous platform area within 60 s was 1.50 (1.00, 2.00), significantly less than the sham group [4.00 (2.75, 4.00)] (t=9.75, P=0.003); no significant differences between the low-intensity group [2.50 (2.00, 3.00)] and the sham one (t=4.50, P=0.382). Immunohistochemistry showed that the nestin⁺ cell density in the low-intensity group [(35.36±4.32) cell/mm²] and high-intensity group [(26.51±5.89) cell/mm²] were significantly lower than the sham group [(59.58±14.15) cell/mm²] (t=24.21, P=0.018; t=33.07, P=0.005); as for the mean absorbance of DCX⁺ cells, the low-intensity group (0.007±0.002) and the high-intensity group (0.006±0.002) were significantly lower than the sham group (0.011±0.001) (t=0.004, P=0.018; t=0.006, P=0.005); compared with the sham group [(1.13±0.14)×10³ cell/mm²], the density of NeuN⁺ neurons in the high-intensity group [(0.75±0.08)×10³ cell/mm²] was significantly reduced (t=0.38, P=0.017), and was not significantly changed in the low-intensity group [(0.88±0.19)×10³ cell/mm²] (t=0.25, P=0.075). Western blotting results showed that, compared with the sham group, the expression levels of nestin, DCX, and NeuN were significantly reduced in the high-intensity group (t=0.74, P<0.001; t=0.18, P=0.014; t=0.35, P=0.008), but were not statistically changed in the low-intensity group (t=0.18, P=0.108; t=0.08, P=0.172; t=0.19, P=0.077). Conclusions: Pg injected through tail vein may reduce learning and memory abilities of wild-type rats, and may reduce the number of nestin, DCX, and NeuN-positive cells, and the protein expression levels of the above molecules in the hippocampus.

Metabolic profiling of lysophosphatidylcholines in chlorpromazine hydrochloride- and N-acetyl-p-amino-phenoltriptolide-induced liver injured rats based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry

Chlorpromazine hydrochloride (CH) and N-acetyl-p-amino-phenoltriptolide (APAP) are typical acentral dopamine receptor antagonists and antipyretic analgesics in clinical applications, respectively. However, it has been reported that these 2 drugs could cause liver damage. Lysophosphatidylcholines (LPCs) have multiple physiological functions and are metabolized primarily in the liver, where it undergoes significant changes when the liver is damaged. In the study, 15 LPCs in the rat serum with CH- and APAP-induced liver injury were quantified based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry, and multivariate statistical analyses including principal component analysis (PCA) and orthogonal partial least squares discriminate analysis (OPLS-DA) were combined to understand CH- and APAP-induced liver injury from the perspective of LPC metabolic profiling. The quantitative results showed that there were significant changes in 10 LPCs and 5 LPCs after CH- and APAP-administration, separately. The results of PCA and OPLS-DA indicated that CH- and APAP-induced liver injury could be well distinguished by the LPC metabolic profiling, and 7 LPCs and 1 LPC biomarkers that could characterize CH- and APAP-induced liver damage in turn had been screened. This study will not only provide a new perspective for the clinical diagnosis of CH- and APAP-induced liver injury, but also offer a reference for further study of their hepatotoxicity mechanisms.

Association between outdoor particulate air pollution and the risk of osteoporosis: a systematic review and meta-analysis

Air pollution is a major threat to global health, which is associated with several adverse health outcomes and increased mortality. Few studies have investigated the association between air pollution and osteoporosis, and their findings were inconclusive. Our objective is to determine whether exposure to outdoor air pollution is causally associated with risk of osteoporosis. A systematic literature search of PubMed, Web of Science, Embase, and Cochrane Library for publications up to December 2020 was conducted for studies reporting the association between air pollution and osteoporosis. Meta-analysis was performed to estimate the pooled effect size of air pollution on osteoporosis using the relative risk (RR) and 95% confidence intervals (95% CI). Quality assessment was conducted, and all statistical analyses were performed by RevMan 5.3 software. Our search identified 9 eligible studies involving 9,371,212 patients. Meta-analysis revealed that there was an increased risk of osteoporosis (total body BMD and hip fracture) as a result of exposure to air pollution including PM_2.5 and NO₂. However, no significant excess risk of osteoporosis was found regardless of PM₁₀, NO, and O₃. In spite of a few number of epidemiological studies selected in the present literature review, this study indicated that the increased exposure to air pollutants was positively associated with high risk of osteoporosis. Further cohort studies with large sample sizes are needed to investigate different constituents and the duration of exposure of air pollutants.

[Clinical features and early diagnostic clues of chronic granulomatous disease]

Objective: To explore the early clinical clues for diagnosis of chronic granulomatous disease (CGD). Methods: One hundred and thirty-nine children with CGD seen in Beijing Children's Hospital from January 2007 to October 2020 were included in this study. The clinical features including age of onset, first presentations, reason for being hospitalized, etiology, imaging features, clues for early diagnosis of all patients were evaluated retrospectively. According to the time of diagnosis, the patients were divided into two groups, cases diagnosed before 2015 and after 2015 and 2015. The time of diagnosis, the length of stay and the hospital charges were compared between the two groups. T test and χ² test were used for statistical analyses. Results: One hundred and nineteen of the cases were males and 20 were females. The age of onset was 4 months (8 d to 14 years), and 103 cases (74.1%) had onset before 1 year of age. The age at diagnosis was 1.8 years (21 d to 14.7 years), and the time of diagnosis delay was 1 year (7 d to 13.7 years). One hundred and thirty-five cases (97.1%) had pulmonary infection as the main reason for hospitalization, of whom 76 cases (56.3%) had positive pulmonary etiology. One hundred and thirty-six patients (97.8%) were referred cases, of whom 5 were suspected of CGD before referral, and the misdiagnosis rate was as high as 96.3% (131/136). Eight early clues for diagnosis were found, the frequency from high to low, large bacillus Callmette-Guer scar in 99 cases (70.5%), left axillary lymphadenopathy or calcification in 73 cases (52.5%), skin or other lymph node infections in 58 cases (41.7%), skin scars in 50 cases (36.0%), multiple lung nodules in 42 cases (30.2%), perianal abscess in 35 cases (25.2%), pulmonary Aspergillus infection in 26 cases (18.7%) and pulmonary Burkholderia infection in 15 cases (10.8%). A total of 120 cases of CGD were diagnosed by respiratory burst test during hospitalization, including 55 cases diagnosed before 2015 and 65 cases diagnosed after 2015. After using these 8 early diagnosis clues, the cases diagnosed after 2015 had shorter time of diagnosis and the length of stay and lower hospitalization charge than cases diagnosed before 2014, and the difference was statistically significant ((25±7) vs. (10±5) d, (29±7) vs. (18±6) d, (3.7×10⁴±1.2×10⁴) vs. (3.2×10⁴±1.2×10⁴) Yuan, t=13.763, 9.262, 2.381, all P<0.05). Conclusions: Patients with CGD are younger at onset and the diagnosis is delayed. Pulmonary infections are the most common. Large BCG scar, left axillary lymphadenopathy or calcification, skin or other lymph node infections, skin scars, multiple lung nodules, perianal abscesses, pulmonary Aspergillus infection and Burkholderia infection can help early diagnosis of CGD.

[A multi-center retrospective study of perioperative chemotherapy for gastric cancer based on real-world data]

Objective: To explore the effect of perioperative chemotherapy on the prognosis of gastric cancer patients under real-world condition. Methods: A retrospective cohort study was carried out. Real world data of gastric cancer patients receiving perioperative chemotherapy and surgery + adjuvant chemotherapy in 33 domestic hospitals from January 1, 2014 to January 31, 2016 were collected. Inclusion criteria: (1) gastric adenocarcinoma was confirmed by histopathology, and clinical stage was cT2-4aN0-3M0 (AJCC 8th edition); (2) D2 radical gastric cancer surgery was performed; (3) at least one cycle of neoadjuvant chemotherapy (NAC) was completed; (4) at least 4 cycles of adjuvant chemotherapy (AC) [SOX (S-1+oxaliplatin) or CapeOX (capecitabine + oxaliplatin)] were completed. Exclusion criteria: (1) complicated with other malignant tumors; (2) radiotherapy received; (3) patients with incomplete data. The enrolled patients who received neoadjuvant chemotherapy and adjuvant chemotherapy were included in the perioperative chemotherapy group, and those who received only postoperative adjuvant chemotherapy were included in the surgery + adjuvant chemotherapy group. Propensity score matching (PSM) method was used to control selection bias. The primary outcome were overall survival (OS) and progression-free survival (PFS) after PSM. OS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the last effective follow-up or death. PFS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the first imaging diagnosis of tumor progression or death. The Kaplan-Meier method was used to estimate the survival rate, and the Cox proportional hazards model was used to evaluate the independent effect of perioperative chemo therapy on OS and PFS. Results: 2 045 cases were included, including 1 293 cases in the surgery+adjuvant chemotherapy group and 752 cases in the perioperative chemotherapy group. After PSM, 492 pairs were included in the analysis. There were no statistically significant differences in gender, age, body mass index, tumor stage before treatment, and tumor location between the two groups (all P>0.05). Compared with the surgery + adjuvant chemotherapy group, patients in the perioperative chemotherapy group had higher proportion of total gastrectomy (χ(2)=40.526, P<0.001), smaller maximum tumor diameter (t=3.969, P<0.001), less number of metastatic lymph nodes (t=1.343, P<0.001), lower ratio of vessel invasion (χ(2)=11.897, P=0.001) and nerve invasion (χ(2)=12.338, P<0.001). In the perioperative chemotherapy group and surgery + adjuvant chemotherapy group, 24 cases (4.9%) and 17 cases (3.4%) developed postoperative complications, respectively, and no significant difference was found between two groups (χ(2)=0.815, P=0.367). The median OS of the perioperative chemotherapy group was longer than that of the surgery + adjuvant chemotherapy group (65 months vs. 45 months, HR: 0.74, 95% CI: 0.62-0.89, P=0.001); the median PFS of the perioperative chemotherapy group was also longer than that of the surgery+adjuvant chemotherapy group (56 months vs. 36 months, HR=0.72, 95% CI:0.61-0.85, P<0.001). The forest plot results of subgroup analysis showed that both men and women could benefit from perioperative chemotherapy (all P<0.05); patients over 45 years of age (P<0.05) and with normal body mass (P<0.01) could benefit significantly; patients with cTNM stage II and III presented a trend of benefit or could benefit significantly (P<0.05); patients with signet ring cell carcinoma benefited little (P>0.05); tumors in the gastric body and gastric antrum benefited more significantly (P<0.05). Conclusion: Perioperative chemotherapy can improve the prognosis of gastric cancer patients.

Immunomodulatory effects of IL-33 and IL-25 in an ovalbumin-induced allergic rhinitis mouse model

Both interleukin (IL)-33 and IL-25 induce Th2-type cytokine production by various cell types, suggesting that they may contribute to development of allergic disorders, however, the immunomodulatory effects of IL-33 and IL-25 in ovalbumin (OVA)-induced allergic rhinitis (AR) remain unclear. In the present study, anti-IL-33 and anti-IL-25 Abs were administrated intranasally during rechallenge in OVA-induced AR. Immunomodulatory effects were evaluated by measuring nasal rubbing, sneezing occurrence, serum OVA-specific antibodies, Th2 immune responses, neutrophil, eosinophil and mast cell recruitment into the nasal mucosa. We found that treatment with anti-IL-33 Ab markedly reduced nasal rubbing, sneezing events, Th2 immune responses, serum OVA-specific IgE and IgG1 levels, mucosal neutrophil, eosinophil and mast cell infiltration. In contrast, the effect of IL-25 antagonism was limited to attenuating the Th2 immune responses, and neutrophil and eosinophil infiltration. These observations indicate that IL-33 and IL-25 play a pathogenic role in an established AR mouse model, with a greater contribution of IL-33 than IL-25. Our findings suggest that IL-33 neutralization may be a potential approach for treatment of AR.

[Clinical features of cystic fibrosis associated allergic bronchopulmonary aspergillosis in children]

Objective: To analyze the clinical features of cystic fibrosis (CF) associated allergic bronchopulmonary aspergillosis (ABPA) in children. Methods: A retrospective study was performed in 22 children who were diagnosed with CF associated ABPA in Beijing Children's Hospital affiliated to Capital Medical University from March 2010 to March 2020. The clinical features, imaging characteristics, laboratory results and the prognosis were reviewed. Results: A total of 22 cases met the diagnostic criterion, including 12 males and 10 females. The age of diagnosis was (10.4±2.8) years and the age of onset was (5.5±4.4) years. Clinical manifestations included cough and expectoration (22 cases), recurrent wheezing (15 cases), hemoptysis (7 cases), failure to thrive (12 cases), pancreatitis (10 cases), hepatomegaly (7 cases), splenomegaly (4 cases) and steatorrhea (4 cases). CT scans of all the patients showed pulmonary infiltrates and central bronchiectasis, combined with mucoid impaction in 17 cases and high density mucus plug in 12 cases. Eosinophilia was found in 18 patients. Total IgE and serum levels of A. fumigatus-specific IgE were elevated in all 22 patients. Positive culture of sputum or bronchoalvedar lauage fluid for fungus were in 15 cases, with single Aspergillus infection in 8 cases and mixed Aspergillus infection in 3 cases. The predominant bacteria found in the airways were Pseudomonas aeruginosa (17 cases), followed by staphylococcas. aureus (6 cases) and stenotrophomonas. maltophilia (5 cases). Pulmonary function revealed obstructive ventilation dysfunction in 4 cases, mixed dysfunction in 11 cases, and small airway dysfunction in 4 cases. Regarding the treatment, 3 were treated only with systemic corticosteroid, while the remaining 19 cases also received antifungal agents.The follow up continued for 1-7 years, and 6 maintained remission, 10 had recurrent episodes, 1 died, and 5 lost to follow up. Conclusions: CF associated ABPA is extremely rare in China. The overlapping clinical, radiographic, and immunologic features of these two diseases make the diagnosis challenging. Systemic corticosteroids are considered the first-line therapy for these patients, and adjuvant antifungal agents may be helpful. Recurrence rate in our center is high.

[Clinical application of HRCT three-dimensional reconstruction in traumatic ossicular chain interruption]

Objective:To investigate the clinical value of HRCT three-dimensional reconstruction technique in traumatic auditory chain traumatic fracture. Method:The clinical data of 14 patients with traumatic ear ossicular chain interruption were analyzed retrospectively. To evaluate the injury site and degree of the auditory chain before surgery, all the 14 patients underwent,HRCT scanning and three-dimensional reconstruction. The reconstructed auditory chain was observed from multiple angles and compared with the surgical exploration results under microscope. Result:The coincidence rate between ossicular chain injury observed by temporal bone HRCT scan before operation and ossicular chain injury observed during surgery was only 28.57%, the coincidence rate between ossicular chain injury observed during surgery and ossicular chain injury observed by three-dimensional reconstruction is 85.71%.Therefore, three-dimensional reconstruction imaging technique could give the doctor more clearly and stereoscopic images for the destruction of ossicular chain. Conclusion:Preoperative three-dimensional reconstruction can display and diagnosis of auditory ossicular chain destruction more clearly. It can be used to accurately evaluate auditory ossicular chain pathological changes, to develop individualized surgical plans and assess the risk of surgery.

[Clinical analysis of methylmalonic acidemia and hyperhomocysteinemia with diffuse lung disease as an initial or main presentation]

Objective: To improve the awareness of methylmalonic acidemia and hyperhomocysteinemia with diffuse lung disease as an initial or main presentation. Methods: A retrospective analysis of the clinical manifestations, radiological features, laboratory tests, genetic variations, treatments and prognoses was conducted in six children presented with diffuse lung disease and finally diagnosed with methylmalonic acidemia and hyperhomocysteinemia in Ward 2 of Department of Respiratory Diseases, Beijing Children's Hospital, from August 2017 to November 2018. Results: Six children were included in this study. Two children were male and four were female. The average age of onset was 28 months. The mean age at diagnosis was 34 months. The average interval from onset to diagnosis was 6 months. Four children who underwent genetic tests were found to have variants of gene MMACHC and diagnosed with CblC type. All children had respiratory symptoms and signs as initial or main presentation, which were tachypnea (5 cases), exercise intolerance (5 cases), cough (4 cases), cyanosis (4 cases), clubbing (4 cases), dyspnea (3 cases) and retractions (3 cases). Pulmonary arterial hypertension was found in all six children. Pericardial effusion (4 cases), kidney involvement (3 cases), nervous system involvement (3 cases), gastrointestinal system involvement (3 cases) and anemia (2 cases) also coexisted. The high resolution computed tomography (HRCT) features included dilated pulmonary artery (6 cases), ground-glass opacities (4 cases), diffuse poorly defined ground-glass centrilobular nodules (3 cases), pleural effusion (3 cases), thickening of interlobular septum (2 cases), etc. All children had an elevated concentration of methylmalonic acid in urine and homocysteine in plasma. Genetic tests were performed in four patients, and MMACHC genetic mutations were found in all of them. Clinical manifestations, HRCT features and pulmonary arterial hypertension turned better in five children after treatment. One patient who was not regularly followed-up died. Conclusions: Pulmonary involvement including diffuse lung disease and pulmonary arterial hypertension could coexist with methylmalonic acidemia and hyperhomocysteinemia, which may have respiratory symptoms and signs as the initial or main presentation. Characteristic HRCT features were found in some patients. Plasma homocysteine test is a quick method for screening the disease in children with diffuse lung disease and (or) pulmonary arterial hypertension. Both diffuse lung disease and pulmonary arterial hypertension may turn better after treatment.

[A study on the pedigree of the academic inheritance of Li Shicai]

Li Shicai, a famous physician of Ming Dynasty had a large number of students. Shen Langzhong, who was a student of Li Shicai, was the teacher of Ma Yuanyi, and one of Ma's student was You Zaijing. This inheritance pedigree was called "Li Shicai School" in academic communities. There were little of study on its later physicians after You Zaijing. This paper collated the medical works, genealogy, local chronicles and medical records of Li Shicai and doctors of different generations. We clarified the academic inheritance genealogy of the past four hundred years. Up to now, there have been twelve generations totally.

[Research on the factors affecting the postoperative outcome of otosclerosis]

Summary Otosclerosis is not often seen in the clinic, but it can seriously affect the quality of life due to the hearing loss of patients. Currently, the treatment of otosclerosis is mainly surgery. With the development of microsurgical techniques, the treatment of surgery for otosclerosis has been highly praised and widely carried out. However, different surgical methods, assistive techniques and instruments used during surgery, selected placement of prostheses, and varying levels of experience of the surgeon can all affect postoperative outcomes. In order to provide reference for the surgical treatment of otosclerosis in the future，this paper will summarize the factors related to postoperative efficacy of stapes surgery for otosclerosis.

[MicroRNA and sensorineural hearing loss]

Hearing loss caused by disorders throughout the cochlea or auditory pathway called sensorineural hearing loss. The etiology of sensorineural deafness is complex and diverse, and the sensory epithelial cell damage of the inner ear spiral is the main pathological change. MicroRNAs play a role in the regulation of gene expression by inhibiting or degrading the mRNA of target genes. More and more studies have shown that microRNA plays an important role in the development of sensorineural deafness. This article will review the process of microRNA involvement in the development of sensorineural hearing loss.

[Clinical and genetic analysis for activated PI3K-δ syndrome by PIK3CD gene mutation]

OBJECTIVE

To analyze clinical and genetic features of activated PI3K-δ syndrome (APDS), a new form of immunodeficiency disease caused by PIK3CD gene mutation.

METHOD

Data of two patients diagnosed as APDS at Second Department of Respiratory Medicine of Beijing Children's Hospital Affiliated to Capital Medical University in 2015 were retrospectively reviewed. Pathogenetic genes were screened by whole exome sequencing, and identified by first generation sequencing. The identified pathogenetic genes were further verified in patients' parents. Then the gene sequencing results were analyzed.

RESULT

Both patients were females, aged 2 years and 4 months and 5 years respectively. The main clinical features of both cases were recurrent respiratory infections, enlargement of lymph node, hepatosplenomegaly, cytomegalovirus (CMV) or Epstein-Barr virus (EBV) viremia, decreased number of native CD4(+) T cell, inverted CD4(+) /CD8(+) T cell ratio and increased IgM. Patient 1 has decreased IgA and IgG. Patient 2 showed wide follicular hyperplasia of the airway mucosa. Both patients had de novo mutation in c. 3061G>A(E1021K)of PIK3CD gene, which was homozygous in patient 1 and heterozygous in patient 2. Both were treated with 500 mg/kg dose of gamma globulin intravenously at 4-weeks interval. Patient 1 started oral rapamycin therapy at the dose of 1 mg/(m(2)·d) and discontinued the treatment after 2 weeks. Patient 2 was given low dose of oral prednisone. The two patients were followed up for 2 months. The number of respiratory infection in both patients was decreased. Hepatosplenomegaly was subsided, while respiratory tract damage was not improved in patient 2.

CONCLUSION

The clinical manifestations of APDS include recurrent respiratory tract infection, enlargement of lymph nodes, hepatosplenomegaly, and CMV or EBV infection. The immunophenotype is decreased native CD4(+) T cell, inverted CD4(+) /CD8(+) T cell ratio, increased IgM and decreased IgA/IgG for some patients. c. 3061G>A(E1021K)of PIK3CD gene is a common de novo mutation in APDS patients.

The Cold Hardiness of Phrynocephalus erythrurus, the Lizard Living at Highest Altitude in the World

BACKGROUND

Phrynocephalus erythrurus living at Qinghai-Tibet Plateau, is believed to be the highest lizard in the world, but we know little about how these lizards cope with very low temperatures in winter.

OBJECTIVE

The aim of this study was to find the difference of the lizards before and after cold acclimatization.

MATERIALS AND METHODS

In this study the limit of supercooling and inoculative freezing, the concentration of four organic osmolytes, and the activity of lactate dehydrogenase in the plasma were measured in samples shortly after capture and in other samples after 7~8 weeks of acclimatization at 2~4 degree C.

RESULTS

Animals acquired an ability to undergo deeper supercooling and inoculative freezing through the course of acclimatization. We find no regular changes of the four organic osmolytes after the acclimatization.

CONCLUSION

We think that this species of lizard is partly freeze-tolerant and conclude that it uses supercooling to survive in winter.

[Current diagnosis and treatment of pseudoaneurysms of the internal carotid artery in postirradiated nasopharyngeal carcinoma]

Nasopharyngeal carcinoma is one of the most common of head and neck malignant tumors in southern region of China. Till date radiotherapy is considered as the first choice of treatment this disease.Although the rate of occurrence of pseudoaneurysms of the internal carotid artery in post radiation treatment of nasopharyngeal carcinoma is low, it is also a hot topic in department of otolaryngology and doctors because of its dangerous and lifethreatening emergencies.In order to improve the level of diagnosis and treatment of the disease, diagnosis, risk, treatment, prognosis and prevention are current summarized in this report.

Protective effect of kaempferol on LPS plus ATP-induced inflammatory response in cardiac fibroblasts

Inflammatory response is an important mechanism in the pathogenesis of cardiovascular diseases. Cardiac fibroblasts play a crucial role in cardiac inflammation and might become a potential therapeutic target in cardiovascular diseases. Kaempferol, a flavonoid commonly existing in many edible fruits, vegetables, and Chinese herbs, is well known to possess anti-inflammatory property and thus has a therapeutic potential for the treatment of inflammatory diseases. To date, the effect of kaempferol on cardiac fibroblasts inflammation is unknown. In this study, we investigated the anti-inflammatory effect of kaempferol on lipopolysaccharide (LPS) plus ATP-induced cardiac fibroblasts and explored the underlying mechanisms. Our results showed that kaempferol at concentrations of 12.5 and 25 μg/mL significantly suppressed the release of TNF-α, IL-1β, IL-6, and IL-18 and inhibited activation of NF-κB and Akt in LPS plus ATP-induced cardiac fibroblasts. These findings suggest that kaempferol attenuates cardiac fibroblast inflammation through suppression of activation of NF-κB and Akt.

Associations of depression with impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in Chinese adults

AIM

To examine the association between depression and impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes in middle-aged and elderly Chinese people, and whether depression was associated with different treatment regimens or durations of diabetes.

METHODS

A cross-sectional study was performed among 229,047 adults living in the community aged ≥ 40 years from 25 centres in China. The self-reported depression rating scale Patient Health Questionnaire 9 (PHQ-9) was used to diagnose probable and sub-threshold depression. Glucose metabolism status was determined according to World Health Organization 1999 diagnostic criteria.

RESULTS

The numbers of participants with normal glucose regulation, impaired glucose regulation, newly diagnosed diabetes and previously diagnosed diabetes were 120,458, 59,512, 24,826 and 24,251, respectively. The prevalence of sub-threshold depression in the total sample of participants was 4.8% (4.8%, 4.8%, 4.4% and 5.6% from normal glucose regulation to previously diagnosed diabetes, respectively), and the prevalence of probable depression was 1.1% (1.1%, 1.0%, 0.9% and 1.8% from normal glucose regulation to previously diagnosed diabetes, respectively). Compared with participants with normal glucose regulation, those with previously diagnosed diabetes had increased odds of probable depression [odds ratio (OR) = 1.61, 95% confidence interval (CI) 1.39-1.87] and sub-threshold depression (OR = 1.14, 95% CI 1.06-1.24), after adjustment for multiple confounding factors. Newly diagnosed diabetes or impaired glucose regulation was not associated with depression. Among those with previously diagnosed diabetes, insulin treatment was associated with greater odds of depression compared with no treatment or oral anti-diabetic medicine.

CONCLUSION

Previously diagnosed diabetes, but not newly diagnosed diabetes or impaired glucose regulation, was associated with a higher prevalence of depression. Patients receiving insulin were more likely to have depression than those not receiving treatment or being treated with oral anti-diabetic medicine.

[Intervention effect of quercetin on inflammatory secretion of cardiac fibroblasts]

To establish neonatal rat cardiac fibroblast inflammatory secretion model by using LPS 100 microg x L(-1) combined with ATP 5 mmol x L(-1), in order to study the inhibitory effect of quercetin on the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts, further investigate the effect of quercetin on the protein expression of p-NF-kappaB p65 (S276) and p-Akt (S473) by western blot, and discuss the inhibitory effect of quercetin on the inflammatory secretion of cardiac fibroblasts. According to the findings, quercetin with the concentrations between 51.74 micromol x L(-1) and 827.81 micromol x L(-1) had no significant effect on the activity of cardiac fibroblasts. Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of TNF-alpha and IL-1beta induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.01 or P < 0.05). Quercetin with the concentrations of 82.78, 41.39 micromol x L(-1) could notably inhibit the increase of IL-6 induced LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.05), without any notable effect of quercetin with the concentration of 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20. 70 micromol x L(-1) could notably inhibit the NF-kappaB p65 (S276) activation induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 15 min, with the most significant effect in 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of p-Akt(473) expression induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 240 min (P < 0.05). Therefore, this study believes that quercetin could attenuate the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts by inhibiting the activation of NF-kappaB p65 (S276) and Akt (473).

[Protective effect of succinic acid on primary cardiomyocyte hypoxia/reoxygenation injury]

To establish cardiomyocyte hypoxia/reoxygenation injury model by culturing primary cardiomyocytes from suckling SD rats, in order to study the effect of succinic acid on LDH leakage rate cardiomyocyte ischemia/reperfusion injury. Furthermore, flow cytometry and western blot were conducted to detect the effect of succinic acid on cardiomyocyte apoptosis, cleaved caspase-3 and p-Akt, and discuss the protective effect of succinic acid on primary cardiomyocyte hypoxia/reoxygenation injury of primary cardiomyocytes from neonatal SD rats. According to the findings of the study, succinic acid at the concentrations ranging between 31.25 mg x L(-1) and 500 mg x L(-1) had no significant effect on primary cardiomyocyte activity, and succinic acid at the concentrations of 400, 200, 100, 50 mg x L(-1) could notably reduce cardiomyocyte ischemia/reperfusion LDH leakage rate (P < 0.01 or P < 0.05, respectively). Succinic acid at the concentrations of 400 mg x L(-1) and 200 mg x L(-1) could significantly reduce the percentage of cardiomyocyte apoptosis (P < 0.05), and inhibit the protein expression of cleaved caspase-3 caused by cardiomyocyte ischemia/reperfusion (P < 0.05). Succinic acid at the concentration of 400 mg x L(-1) could remarkably increase the protein expression of cardiomyocyte Akt (P < 0.05), while succinic acid at the concentration of 200 mg x L(-1) had no obvious effect on the protein expression of cardiomyocyte Akt. Therefore, this study demonstrated that succinic acid could inhibit necrosis and apoptosis caused by cardiomyocyte hypoxia/reoxygenation by activating Akt phosphorylation.

SLE disease per se contributes to deterioration in bone mineral density, microstructure and bone strength

OBJECTIVE

The objective of this report is to assess the effect of systemic lupus erythematosus (SLE) disease itself on deterioration of bone mineral density (BMD), microstructure and bone strength.

METHOD

Thirty age-matched SLE patients on long-term glucocorticoids (GC) (SLE/GC), 30 SLE patients without GC (SLE/non-GC) and 60 healthy controls were examined. Areal BMD (aBMD) was measured by dual-energy X-ray absorptiometry. Bone geometry, volumetric BMD (vBMD), and architectural parameters at the nondominant distal radius were assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT). Bone strength was estimated by HR-pQCT-based micro-finite element analysis.

RESULTS

Adjusted for menopausal status and adjusted calcium level, when compared with controls, SLE/non-GC patients had significantly lower aBMD at femoral neck and total hip, and diminished radial total vBMD, cortical area, vBMD and thickness, respectively, by 8.3%, 8%, 2.7% and 9.2%, as well as significant compromised bone strength (stiffness, failure load and apparent modulus) by 8.3%, 9.1% and 9.5%, respectively. Similar alterations were also found in SLE/GC patients when compared to controls. In the premenopausal subgroup analysis, when compared with controls, total hip aBMD and radial cortical area were significantly lower in SLE/non-GC patients, and cortical area and thickness were significantly deficit in SLE/GC patients. However, no significant difference in any bone variables was present between SLE/GC and SLE/non-GC patients in the entire cohort or in the premenopausal subgroup.

CONCLUSION

SLE disease per se contributes to the deterioration in bone density, cortical microstructure and bone strength. This might help to explain the considerably higher fracture risk seen in SLE patients.

Alterations of bone geometry, density, microarchitecture, and biomechanical properties in systemic lupus erythematosus on long-term glucocorticoid: a case-control study using HR-pQCT

Compared to controls, HR-pQCT at distal radius of SLE patients on chronic glucocorticoid (SLE/GC) revealed reduced bone area, vBMD, deteriorated microarchitecture, and unevenly distributed stresses limited to cortical bone. Despite similar trabecular quality, whole bone strength decreased in patients. These alterations may partly explain high fracture rates in SLE/GC.

INTRODUCTION

To assess bone geometric, densitometric, microarchitectural, and biomechanical properties in patients with systemic lupus erythematosus (SLE) on long-term glucocorticoid (GC) (SLE/GC) as compared with healthy controls.

METHODS

A total of 180 female SLE patients and 180 healthy controls were in this cross-sectional study to assess areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) and microfinite element analysis (μFEA) was performed at distal radius.

RESULTS

In addition to significantly lower aBMD at femoral neck, total hip and lumbar spine, cortical area, average volumetric BMD (vBMD) and cortical vBMD also significantly reduced by 5.3, 5.7, to 1.9 % in SLE patients, respectively. Deteriorations of cortical microarchitecture were pronounced in patients, with 6.3 % reduction in cortical thickness and 13.6 % higher in cortical porosity. Local stresses were more unevenly distributed through cortical bone in patients. SLE/GC patients had decreased whole bone stiffness, estimated failure load, and apparent modulus. Parameters related to trabecular bone density and microarchitecture were comparable between patients and controls.

CONCLUSION

In SLE/GC patients, despite a reduction in bone area, vBMD and deteriorated microarchitecture and unevenly distributed stresses limited to the cortical compartment, whole bone strength decreased. HR-pQCT and μFEA were promising in elucidating the potential underlying pathophysiology of bone loss and propensity to fracture in SLE/GC and provide us additional information about alterations of bone quality which might better predict fracture risk beyond aBMD in SLE/GC.

1,25-dihydroxyvitamin D3 inhibits fibrosis in mice with NAFLD induced by a methionine-choline-deficient diet

AIM: To investigate whether 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), the active form of vitamin D, inhibits fibrosis induced by a methionine-choline-deficient (MCD) diet in C57BL/6J mice and to explore the possible mechanisms involved.

METHODS: Male C57BL/6J mice (n = 30) were divided randomly into control group, MCD group, and MCD + 1,25(OH)₂D₃ group. The MCD and MCD + 1,25(OH)₂D₃ groups were fed a MCD diet. All the mice were intraperitoneally injected with 1,25(OH)₂D₃ (5 μg/kg) or equal volume of saline twice weekly. After 8 wk, the mice were sacrificed to take serum samples for biochemical measurements and liver samples for HE staining and RT-PCR.

RESULTS: Serum levels of alanine aminotransferase, aspartate aminotransferase, and mRNA expression of transforming growth factor beta1 (TGF-β1), α-smooth muscle actin (α-SMA) and collagenⅠa1 of MCD group significantly increased in the MCD group compared to the control group (P = 0.000, 0.000, 0.044, 0.003, 0.027). In the MCD + 1,25(OH)₂D₃ group, all the above parameters significantly decreased (P = 0.000, 0.005, 0.020, 0.027) except the mRNA expression of TGF-β1, which showed no significant change, compared to the MCD group. Steatosis was significantly improved, as revealed by the presence of fewer lipid drops in the cytoplasm and less inflammatory cell infiltration around the vessels, in the MCD + 1,25(OH)₂D₃ group compared to the MCD group.

CONCLUSION: 1,25(OH)₂D₃ can improve liver function and inhibit fibrosis possibly by down-regulating the mRNA expression of α-SMA and collagenⅠa1 in mice with NAFLD induced by a MCD diet.

Ferulic acid induces heme oxygenase-1 via activation of ERK and Nrf2

This study investigated the effect of ferulic acid (FA) on the up-regulation of heme oxygenase-1 (HO-1) in lymphocytes and the molecular mechanisms involved. Lymphocytes were treated with FA (0.001-0.1 μM) for certain times. Cell viability, the activity and level of expression of HO-1, and signal pathways were analyzed. FA significantly upregulated HO-1 expression both at the level of mRNA and protein in lymphocytes. Moreover, FA induced NF-E2-related factor (Nrf2) nuclear translocation and transcriptional activity, which is upstream of FA induced HO-1 expression. In addition, lymphocytes treated with FA exhibited activation of extracellular regulated kinase (ERK) and treatments with U0126 (an ERK kinase inhibitor) attenuated the FA induced activation of Nrf2, resulting in a decrease in HO-1 expression. Zinc protoporphyrin (ZnPP, a HO-1 inhibitor) markedly suppressed cytoprotection from radiation-induced cell damage by FA. Results suggested that the ERK signaling pathway controlled the anti-oxidation of FA by regulating the expression of the antioxidant enzyme HO-1.

Computer aided diagnosis system for breast cancer based on color Doppler flow imaging

Color Doppler flow imaging takes a great value in diagnosing and classifying benign and malignant breast lesions. However, scanning of color Doppler sonography is operator-dependent and ineffective. In this paper, a novel breast classification system based on B-Mode ultrasound and color Doppler flow imaging is proposed. First, different feature extraction methods were used to obtain the texture and geometric features from B-Mode ultrasound images. In color Doppler feature extraction stage, several spectrum features are extracted by applying blood flow velocity analysis to Doppler signals. Moreover, a velocity coherent vector method is proposed based on color coherence vector, which is helpful for designing to the optimize detection of flow indices from different blood flow velocity fields automatically. Finally, a support vector machine classifier with selected feature vectors is used to classify breast tumors into benign and malignant. The experimental results demonstrate that the proposed computer-aided diagnosis system is useful for reducing the unnecessary biopsy and death rate.

Genome-wide identification, classification, and analysis of two-component signal system genes in maize

Cytokinins play many vital roles in plant development and physiology. In plants, cytokinin signals are sensed and transduced by the two-component signal system. This signaling cascade is typically composed of three proteins: a sensory histidine kinase, a histidine phosphotransfer protein, and a response regulator. Through a comprehensive genome-wide analysis of the maize (Zea mays) genome, 48 genes were identified, including 11 ZmHKs, 9 ZmHPs, and 28 ZmRRs (21 A-type ZmRRs and 7 B-type ZmRRs). Using maize genome sequence databases, we analyzed conserved protein motifs and established phylogenetic relationships based on gene structure, homology, and chromosomal location. The duplication of these two-component system genes in the maize genome corresponded to the clusters of these genes in the phylogenetic trees. Sequence analysis of the duplicate genes demonstrated that one gene may be in gene duplication, and that there was significant variation in the evolutionary history of the different gene families. We assessed the expression levels of all ZmRRs in the leaves and roots by reverse transcription PCR; they were all found to be active. Our results provide a foundation for functional and evolutionary studies on maize two-component signal system proteins.

Seasonal variation of the particle size distribution of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in urban aerosol of Guangzhou, China

Seasonal aerosol samples have been collected by Andersen Hi-Vol pumping system equipped with a five stage cascade impactor and a backup filter (size range: 10-7.2 microm, 7.2-3.0 microm, 3.0-1.5 microm, 1.5-0.95 microm, 0.95-0.49 microm, <or=0.49 microm) in the Liwan district, Guangzhou. n-Alkanes were measured using gas chromatography and PAHs were measured using gas chromatography/mass spectrometry analysis. The bimodal log-normal distributions of n-alkanes and semi-volatile PAHs were found, while for non-volatile PAHs that was unimodal, so much as the mode of semi-volatile PAHs was similar with that of the particles. The n-alkanes and PAHs were preferably associated with fine particles. C (max) (carbon number maximum) (C(22)-C(26)), CPI (carbon preference index) (1.12-1.21), U/R (unresolved to resolved components ratio) (7.42-10.7), wax% (0.9-3.12%) and the diagnostic ratios for PAHs revealed that vehicular emission was the major source of these organic compounds during the study periods, while the contribution of epicuticular waxes emitted by terrestrial plants was minor. CPI(2) (values for petrogenic hydrocarbons), CPI(3) (values for biogenic n-alkanes) and wax% revealed that the natural preferentially accumulated in the larger aerosol while the anthropogenic in the smaller. In addition, the different MMDs (mass median diameters) for n-alkanes and PAHs were observed in different seasons. The MMDs for n-alkanes and PAHs were higher in autumn/winter than those in spring/summer. The seasonal effect was related to the hydrocarbon content in the individual particulate fractions, showing a preferential association of n-alkanes and PAHs with larger particles in the autumn/winter season.

Use of bispecific antibodies in molecular velcro assays whose specificity approaches the theoretical limit of immunodetection for Bordetella pertussis

A bispecific monoclonal antibody (bsMAb) that detects Bordetella pertussis, the causative agent of whooping cough, and horseradish peroxidase (HRPO) has been developed by use of the quadroma technology. A quadroma, P123, was produced by fusing two well-characterized hybridomas against the bacterium and the enzyme and was subcloned to obtain a stable bsMAb-secreting cell line. The quadroma was theoretically expected to produce up to 10 different molecular species of immunoglobulins, so secreted bispecific antibody was complexed with excess HRPO and the HRPO-bsMAb complex was purified in one step by benzhydroxamic acid-agarose affinity cochromatography. An ultrasensitive homosandwich molecular "velcro" enzyme-linked immunosorbent assay for the detection of B. pertussis whole bacteria with HRPO-bsMAb was established in both microplate and nasopharyngeal swab formats. This assay demonstrates a high sensitivity that approaches the theoretical limit of detection of one bacterium. This new nanoprobe can be used to develop a new generation of assays that are simple, inexpensive alternatives to quantitative PCR and that can be used by clinical laboratories. This strategy of homosandwich assays with solid-phase monospecific antibodies and solution-phase bsMAb with specificity for the same repeating surface determinants can be applied to generate ultrasensitive immunodiagnostic assays for viruses and bacteria.

[Changes in T-lymphocyte subsets of peripheral blood in patients with filarial chyluria]

OBJECTIVE

To study the changes in T-lymphocyte subsets CD4+:CD8+ of peripheral blood in 29 patients with present chyluria(PPC), 29 patients with chyluria history but without chyluria (PNPC) and 38 healthy controls.

METHODS

The determination of CD3+, CD4+ and CD8+ was conducted using test reagents kits.

RESULTS

The percentage of CD3+, CD4+ cell were signfcantly decreased in PPS group than in PNPC and healthy control group, the ratio of CD4+/CD8+ being under 1.0. The T-lymphocyte subsets (CD3+, CD4+, CD8+) and CD4+/CD8+ ratio of both PNPC and healthy control group were all within normal range.

CONCLUSION

The immune function of the patients with filarial chyluria was impaired in terms of the changes in T-lymphocyte subsets.

[Synthesis and determination for enantiomeric purity of 6-fluoro-L-DOPA]

AIM

To study the synthesis and determination for enantiomeric purity of 6-fluoro-L-3, 4-dihydroxyphenylalanine (6-fluoro-L-DOPA, 6-FDOPA).

METHODS

2-(2-Fluoro-4, 5-dimethoxybenzyl)-N-(diphenylmethylene) glycine tert-butyl ester (8), a new compound, was synthesized from the starting material nitroveratraldehyde via the nucleophilic displacement, reductive iodination, and chiral catalytic phase-transfer alkylation, and 6-FDOPA was prepared from hydrolysis of 8. The enantiomeric purity of 6-FDOPA was determined by HPLC method using a chiral mobil phase and reversed-phase C18 column.

RESULTS

The total time of synthesis was less than 90 min, the overall chemical yield from potassium fluoride was about 33%, and the enantiomeric purity was above 95%.

CONCLUSION

Large scale production of 6-FDOPA and automatic synthesis of 6-[18F]fluoro-L-DOPA with excellent chemical and entiomeric purity are available. The practical technique was provided for the radiochemical synthesis and entiomeric purity of 6-[18F]fluoro-L-DOPA.

Protection of IB-MECA against myocardial stunning in conscious rabbits is not mediated by the A1 adenosine receptor

The goal of this study was to determine whether the protective effects of the A3AR agonist N6-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (IB-MECA) against myocardial stunning are mediated by the A1AR. Six groups of conscious rabbits underwent a sequence of six 4-minute coronary occlusion (O)/4-minute reperfusion (R) cycles for three consecutive days (days 1, 2, and 3). In vehicle-treated rabbits (group I), the recovery of systolic wall thickening (WTh) in the ischemic/reperfused region was markedly depressed on day 1, indicating the presence of severe myocardial stunning. On days 2 and 3, however, the recovery of systolic WTh was markedly accelerated, indicating the presence of late ischemic preconditioning (PC). When rabbits were pretreated with the A1AR agonist 2-chloro-N6-cyclopentyladenosine (CCPA, 100 microg/kg i.v.) or with IB-MECA (100 microg/kg i.v.) 10 min prior to the first sequence of O/R cycles on day 1 (group III and V, respectively), the recovery of systolic WTh was markedly accelerated compared to vehicle-treated animals (reflected as an approximately 48% decrease in the total deficit of systolic WTh). The magnitude of the protection afforded by adenosine receptor agonists was equivalent to that provided by late ischemic PC. Pre-treating rabbits with the A1AR antagonist N-0861 completely blocked both the hemodynamic and the cardioprotective effects of CCPA (group IV). However, the same dose of N-0861 did not block the cardioprotective actions of IB-MECA (group VI). Importantly, N-0861 did not influence the degree of myocardial stunning in the absence of PC (group II) and it did not block the development of late ischemic PC. Taken together, these results provide conclusive evidence that the cardioprotective effects of IB-MECA are not mediated via the A1AR, supporting the concept that activation of A3ARs prior to an ischemic challenge provides protection against ischemia/reperfusion injury.

Nitroglycerin induces late preconditioning against myocardial infarction in conscious rabbits despite development of nitrate tolerance

BACKGROUND

Recent studies suggest that the late phase of ischemic preconditioning (PC) can be mimicked by pretreatment with NO donors. The ability of clinically relevant NO donors to induce PC against infarction, however, has not been evaluated. Furthermore, it is unknown whether tolerance to the hemodynamic actions of nitrates also extends to their PC effects.

METHODS AND RESULTS

Conscious rabbits underwent a 30-minute coronary occlusion and 3 days of reperfusion. A 60-minute intravenous (IV) infusion of nitroglycerin (NTG) ending 1 hour before occlusion reduced infarct size, indicating an early PC effect. When the time interval between NTG infusion and occlusion was extended to 24 or 72 hours, the infarct-sparing action of NTG became even more pronounced, indicating a robust late PC effect. Transdermal NTG patches elicited a late PC effect that was (1) equivalent to that induced by IV NTG, demonstrating the efficacy of transdermal NTG as an alternative form of NTG delivery for inducing late PC, and (2) similar in nitrate-tolerant and -nontolerant rabbits, demonstrating that tolerance does not extend to the PC effects of NTG.

CONCLUSIONS

In conscious rabbits, administration of NTG via either the IV or the transdermal route elicits a robust protective effect against infarction that lasts for 72 hours. The magnitude of NTG-induced cardioprotection is equivalent to that observed during the late phase of ischemic PC and is not affected by the development of tolerance. These findings reveal a new action of nitrates and support novel applications of these drugs for protecting the ischemic myocardium in patients.

Cyclooxygenase-2 does not mediate late preconditioning induced by activation of adenosine A1 or A3 receptors

Recent studies have demonstrated that the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) and the adenosine A3 receptor agonist N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA) produce a delayed phase of protection against infarction similar to the late phase of ischemic preconditioning (PC). However, the mechanism for adenosine A1 or A3 receptor-induced late PC remains unknown. The goal of this study was to determine whether the delayed cardioprotective effects of adenosine A1 or A3 receptors are mediated by cyclooxygenase-2 (COX-2), which is an obligatory mediator of ischemic PC. We found that COX-2 protein expression (Western blotting) did not increase 24 h after the administration of either CCPA (100 microg/kg iv) or IB-MECA (300 microg/kg iv) compared with controls. To probe the role of constitutive COX-2 expression, conscious rabbits were subjected to 30-min coronary occlusion followed by 72-h reperfusion. Twenty-four hours before the occlusion, the rabbits were pretreated with CCPA (100 microg/kg iv) or IB-MECA (300 microg/kg iv). Both CCPA and IB-MECA resulted in a marked (approximately 47%) reduction in infarct size vs. controls [36.2 +/- 4.0% of the risk region (n = 9), 31.2 +/- 4.7% (n = 9), and 59.5 +/- 3.8% (n = 9), respectively; P < 0.05], similar to that induced by the late phase of ischemic PC [31.8 +/- 3.2% (n = 9)]. The selective COX-2 inhibitor N-(2-[cyclohexyloxy]4-nitrophenyl)methanesulfonamide (NS-398, 5 mg/kg), which abolished the protective effect of ischemic late PC, failed to block the protection of either CCPA or IB-MECA, indicating that COX-2 does not mediate the delayed protection of either CCPA or IB-MECA [CCPA + NS-398, 29.1 +/- 3.4% (n = 7); IB-MECA + NS-398, 34.9 +/- 2.9% (n = 8)]. NS-398 in itself did not affect infarct size [54.9 +/- 3.7% (n = 9)]. Taken together, these results demonstrate that, in contrast to ischemia-induced late PC, the mechanisms of adenosine A1 or A3 receptor-induced late PC is independent of COX-2.

Protein kinase C epsilon-Src modules direct signal transduction in nitric oxide-induced cardioprotection: complex formation as a means for cardioprotective signaling

An essential role for protein kinase C epsilon (PKCepsilon) has been shown in multiple forms of cardioprotection; however, there is a distinct paucity of information concerning the signaling architecture that is responsible for the manifestation of a protective phenotype. We and others have recently shown that signal transduction may proceed via the formation of signaling complexes (Circ Res. 2001;88:59-62). In order to understand if the assembly of multiprotein complexes is the manner by which signaling is conducted in cardioprotection, we designed a series of experiments to characterize the associations of Src tyrosine kinase with PKCepsilon in a conscious rabbit model of nitric oxide (NO)-induced late preconditioning. Our data demonstrate that PKCepsilon and Src can form functional signaling modules in vitro: PKCepsilon interacts with Src; the association with PKCepsilon activates Src; and adult cardiac cells receiving recombinant adenoviruses encoding PKCepsilon exhibit increased Src activity. Furthermore, our results show that NO-induced late preconditioning involved PKCepsilon-Src module formation and enhanced the enzymatic activity of PKCepsilon-associated Src. Inhibition of PKC blocked cardioprotection, module formation, and PKCepsilon-associated Src activity, providing direct evidence for a functional role of the PKCepsilon-Src module in the orchestration of NO-induced cardioprotection in conscious rabbits.

Gene therapy with extracellular superoxide dismutase protects conscious rabbits against myocardial infarction

BACKGROUND

Extracellular superoxide dismutase (Ec-SOD) may protect the heart against myocardial infarction (MI) because of its extended half-life and capacity to bind heparan sulfate proteoglycans on cellular surfaces. Accordingly, we used direct gene transfer to increase systemic levels of Ec-SOD and determined whether this gene therapy could protect against MI.

METHODS AND RESULTS

The cDNA for human Ec-SOD was incorporated into a replication-deficient adenovirus (Ad5/CMV/Ec-SOD). Injection of this virus produced a high level of Ec-SOD in the liver, which was redistributed to the heart and other organs by injection of heparin. Untreated rabbits (group I) underwent a 30-minute coronary occlusion and 3 days of reperfusion. For comparison, preconditioned rabbits (group II) underwent a sequence of six 4-minute-occlusion/4-minute-reperfusion cycles 24 hours before the 30-minute occlusion. Control-treated rabbits (group III) were injected intravenously with Ad5/CMV/nls-LacZ, and gene-therapy rabbits (group IV) were injected with Ad5/CMV/Ec-SOD 3 days before the 30-minute occlusion. Both groups treated with Ad5 received intravenous heparin 2 hours before the 30-minute occlusion. Infarct size (percent risk area) was similar in groups I (57+/-6%) and III (58+/-5%). Ec-SOD gene therapy markedly reduced infarct size to 25+/-4% (P<0.01, group IV versus group III), a protection comparable to that of the late phase of ischemic preconditioning (29+/-3%, P<0.01 group II versus group I).

CONCLUSIONS

Direct gene transfer of the cDNA encoding membrane-bound Ec-SOD affords powerful cardioprotection, providing proof of principle for the effectiveness of antioxidant gene therapy against MI.

A(1) or A(3) adenosine receptors induce late preconditioning against infarction in conscious rabbits by different mechanisms

We investigated whether activation of A(1) or A(3) adenosine receptors (ARs) induces late preconditioning (PC) against infarction in conscious rabbits using the selective AR agonists 2-chloro-N(6)-cyclopentyladenosine (CCPA) and N(6)-3-iodobenzyladenosine-5'-N-methylcarboxamide (IB-MECA). In vitro radioligand binding and cAMP assays demonstrated CCPA to be approximately 200- to 400-fold selective for the rabbit A(1)AR and IB-MECA to be approximately 20-fold selective for the rabbit A(3)AR. We observed that (1) pretreatment of rabbits 24 hours earlier with CCPA (100 microgram/kg IV bolus) or IB-MECA (100 or 300 microgram/kg) resulted in an approximately 35% to 40% reduction in the size of the infarct induced by 30 minutes of coronary artery occlusion and 72 hours of reperfusion compared with vehicle-treated rabbits, whereas pretreatment with the selective A(2A)AR agonist CGS 21680 (100 microgram/kg) had no effect; (2) the delayed cardioprotective effect of CCPA, but not that of IB-MECA, was completely blocked by coadministration of the highly selective A(1)AR antagonist N-0861; (3) inhibition of nitric oxide synthase (NOS) with N(omega)-nitro-L-arginine during the 30-minute occlusion abrogated the infarct-sparing action of CCPA but not that of IB-MECA; and (4) inhibition of ATP-sensitive potassium (K(ATP)) channels with sodium 5-hydroxydecanoate during the 30-minute occlusion blocked the cardioprotective effects of both CCPA and IB-MECA. Taken together, these results indicate that activation of either A(1)ARs or A(3)ARs (but not A(2A)ARs) elicits delayed protection against infarction in conscious rabbits and that both A(1)AR- and A(3)AR-induced cardioprotection involves opening of K(ATP) channels. However, A(1)AR-induced late PC uses an NOS-dependent pathway whereas A(3)AR-induced late PC is mediated by an NOS-independent pathway.

Late preconditioning enhances recovery of myocardial function after infarction in conscious rabbits

It is unknown whether late preconditioning (PC) enhances the recovery of left ventricular (LV) function after a myocardial infarction. Thus 25 conscious rabbits were subjected to a 30-min coronary occlusion followed by 28 days of reperfusion after PC 24 h earlier with either ischemia or nitric oxide donor administration [S-nitroso-N-acetylpenicillamine (SNAP)]. The recovery of wall thickening (WTh) after reperfusion was significantly improved in the ischemic PC and SNAP PC groups compared with controls, both at rest and during dobutamine stress. Interestingly, neither ischemia- nor SNAP-induced late PC attenuated myocardial stunning from day 1 through day 14. Infarct size was smaller in the ischemic PC and SNAP PC groups compared with controls. In all groups, WTh at 28 days was positively and linearly related to the percentage of viable tissue in the region underlying the ultrasonic crystal (r = 0.90), indicating that the improvement in LV function after both ischemia-induced and NO donor-induced late PC can be fully explained by the reduction in infarct size; a separate effect of late PC on LV remodeling or LV contractility need not be invoked. In conclusion, in conscious rabbits late PC, induced either by ischemia or pharmacologically, not only limits infarct size but also enhances the recovery of LV function after myocardial infarction. This finding has important clinical implications and provides triphenyltetrazolium chloride-independent evidence that late PC limits myocellular death after sustained ischemia.

Biphasic response of cardiac NO synthase isoforms to ischemic preconditioning in conscious rabbits

In conscious rabbits, a sequence of six 4-min coronary occlusion/4-min reperfusion cycles, which elicits late preconditioning (PC), caused rapid activation of calcium-dependent nitric oxide (NO) synthase (NOS) [cNOS; endothelial NOS (eNOS) and/or neuronal NOS (nNOS)], whereas calcium-independent NOS [inducible NOS (iNOS)] activity remained unchanged. The enhanced cNOS activity was associated with increased myocardial levels of NO(2) and/or NO(3) (NO(x)). Twenty-four hours after ischemic PC was induced, the opposite pattern was observed, i.e., there was a pronounced increase in cytosolic iNOS activity but no change in cNOS activity. The initial burst of ischemia-induced cNOS activity was not affected by pretreatment with the antioxidant N-2-mercaptopropionyl glycine (MPG), the protein kinase C (PKC) inhibitor chelerythrine, or the tyrosine kinase inhibitor lavendustin A, indicating that it is independent of the generation of oxidant species and the activation of PKC and tyrosine kinases. In contrast, the delayed upregulation of iNOS 24 h after PC was prevented by pretreatment with N(omega)-nitro-L-arginine, MPG, or chelerythrine before the PC ischemia, indicating that it is triggered by a signaling mechanism that involves the generation of NO, the formation of oxidant species, and the activation of PKC. Taken together, these results demonstrate that, in conscious animals, ischemic PC elicits a biphasic response in cardiac NOS activity, i. e., an immediate activation of cNOS (most likely eNOS) followed 24 h later by a delayed upregulation of iNOS. To our knowledge, this is the first study to directly measure NOS activity after brief myocardial ischemia in vivo. In conjunction with previous functional studies, the data support a distinctive role of NOS isoforms in late PC, with eNOS serving as the trigger on day 1 and iNOS as the mediator on day 2.

Differential role of K(ATP) channels in late preconditioning against myocardial stunning and infarction in rabbits

The role of ATP-sensitive potassium (K(ATP)) channels in the late phase of ischemic preconditioning (PC) remains unclear. Furthermore, it is unknown whether K(ATP) channels serve as end effectors both for late PC against infarction and against stunning. Thus, in phase I of this study, conscious rabbits underwent a 30-min coronary occlusion (O) followed by 72 h of reperfusion (R) with or without ischemic PC (6 4-min O/4-min R cycles) 24 h earlier. Late PC reduced infarct size approximately 46% versus controls. The K(ATP) channel blocker 5-hydroxydecanoic acid (5-HD), given 5 min before the 30-min O, abrogated the infarct-sparing effect of late PC but did not alter infarct size in non-PC rabbits. In phase II, rabbits underwent six 4-min O/4-min R cycles for 3 consecutive days (days 1, 2, and 3). In controls, the total deficit of systolic wall thickening (WTh) after the sixth reperfusion was reduced by 46% on day 2 and 54% on day 3 compared with day 1, indicating a late PC effect against myocardial stunning. Neither 5-HD nor glibenclamide, given on day 2, abrogated late PC. The K(ATP) channel opener diazoxide, given on day 1, attenuated stunning, and this effect was completely blocked by 5-HD. Thus the same dose of 5-HD that blocked the antistunning effect of diazoxide failed to block the antistunning effects of late PC. Furthermore, when diazoxide was administered in PC rabbits on day 2, myocardial stunning was further attenuated, indicating that diazoxide and late PC have additive anti-stunning effects. We conclude that K(ATP) channels play an essential role in late PC against infarction but not in late PC against stunning, revealing an important pathogenetic difference between these two forms of cardioprotection.

Cyclooxygenase-2 mediates the cardioprotective effects of the late phase of ischemic preconditioning in conscious rabbits

We examined the role of cyclooxygenase-2 (COX-2) in the late phase of ischemic preconditioning (PC). A total of 176 conscious rabbits were used. Ischemic PC (six cycles of 4-min coronary occlusions/4-min reperfusions) resulted in a rapid increase in myocardial COX-2 mRNA levels (+231 +/- 64% at 1 h; RNase protection assay) followed 24 h later by an increase in COX-2 protein expression (+216 +/- 79%; Western blotting) and in the myocardial content of prostaglandin (PG)E(2) and 6-keto-PGF(1alpha) (+250 +/- 85% and +259 +/- 107%, respectively; enzyme immunoassay). Administration of two unrelated COX-2 selective inhibitors (NS-398 and celecoxib) 24 h after ischemic PC abolished the ischemic PC-induced increase in tissue levels of PGE(2) and 6-keto-PGF(1alpha). The same doses of NS-398 and celecoxib, given 24 h after ischemic PC, completely blocked the cardioprotective effects of late PC against both myocardial stunning and myocardial infarction, indicating that COX-2 activity is necessary for this phenomenon to occur. Neither NS-398 nor celecoxib lowered PGE(2) or 6-keto-PGF(1alpha) levels in the nonischemic region of preconditioned rabbits, indicating that constitutive COX-1 activity was unaffected. Taken together, these results demonstrate that, in conscious rabbits, up-regulation of COX-2 plays an essential role in the cardioprotection afforded by the late phase of ischemic PC. Therefore, this study identifies COX-2 as a cardioprotective protein. The analysis of arachidonic acid metabolites strongly points to PGE(2) and/or PGI(2) as the likely effectors of COX-2-dependent protection. The recognition that COX-2 mediates the antistunning and antiinfarct effects of late PC impels a reassessment of current views regarding this enzyme, which is generally regarded as detrimental.

Bifunctional role of protein tyrosine kinases in late preconditioning against myocardial stunning in conscious rabbits

Although protein tyrosine kinases (PTKs) have been implicated in late preconditioning (PC) against infarction, their role in late PC against stunning is unknown. Furthermore, it is unknown whether PTK signaling is necessary only to trigger late PC on day 1 or also to mediate it on day 2. Thus, conscious rabbits underwent a sequence of six 4-minute coronary occlusion/4-minute reperfusion cycles for 3 consecutive days (days 1, 2, and 3). In the control group (group I, n=7), the recovery of systolic wall thickening after the 6 occlusion/reperfusion cycles was markedly improved on days 2 and 3 compared with day 1, indicating the development of late PC against stunning. Administration of the PTK inhibitor lavendustin-A (LD-A, 1 mg/kg IV) before the first occlusion on day 1 (group II, n=7) completely prevented the late PC effect against stunning on day 2. Late PC against stunning was also abrogated when LD-A was given before the first occlusion on day 2 (group III, n=7); however, in these rabbits, the late PC effect became apparent on day 3, indicating that LD-A itself did not have any delayed deleterious actions on myocardial stunning. In group V (n=5), the sequence of 6 occlusion/reperfusion cycles resulted in a robust increase in the activity of inducible NO synthase (iNOS [assessed as Ca(2+)-independent L-citrulline formation]) and nitrite+nitrate (NO(x)) tissue levels 24 hours later (on day 2), with no concomitant change in Ca(2+)-dependent NO synthase (endothelial NO synthase and/or neuronal NO synthase) activity. Similar results were obtained on day 3 (group VIII, n=6), indicating sustained upregulation of iNOS. Administration of LD-A either on day 1 (group VI, n=5) or on day 2 (group VII, n=6) abrogated the increase in iNOS activity and NO(x) levels on day 2. LD-A had no effect on iNOS activity or NO(x) levels in the absence of PC (group X, n=5). This study demonstrates that in conscious rabbits, PTK activity is necessary not only to trigger late PC against stunning on day 1 but also to mediate the protection on day 2. This investigation also provides the first direct evidence that cardiac iNOS activity is upregulated during the late phase of ischemic PC in rabbits. Furthermore, the data indicate that PTK signaling is essential for the augmentation of iNOS activity and that PTKs modulate this enzyme at two distinct levels: at an early stage on day 1 and at a late stage on day 2. This bifunctional role of PTKs in late PC has broad implications for the signaling mechanisms that underlie the response of the heart to ischemic stress and, possibly, other stresses.

Nitric oxide donors attenuate myocardial stunning in conscious rabbits

Although previous studies suggested that the protection of late preconditioning (PC) against myocardial stunning is mediated by nitric oxide (NO), direct evidence that exogenous administration of NO attenuates myocardial stunning is lacking. Furthermore, although exogenous NO administration was shown to elicit a late PC phase, it is unknown whether NO donors also induce an early PC phase. Therefore, conscious rabbits underwent two experimental stages (3 days of six 4-min occlusion/4-min reperfusion cycles each) 2 wk apart. In study I, both stages were control stages (n = 7). In studies II and III, stage I was the control stage. On day 1 of stage II, seven rabbits received infusion of nitroglycerin (NTG; 2 microg. kg(-1). min(-1) iv) during the ischemia-reperfusion sequence, starting 30 min before the 1st occlusion and ending 10 min after the 6th reperfusion (study II). Another seven rabbits received infusion of NTG (2 microg. kg(-1). min(-1) iv) for 1 h followed by a 30-min washout interval and then underwent six 4-min occlusion/4-min reperfusion cycles (study III). In the control stage of all three studies, recovery of wall thickening (WTh) after occlusion/reperfusion cycles was markedly enhanced on days 2 and 3 compared with day 1, indicating late PC. In study II, infusion of NTG during the occlusion/reperfusion cycles on day 1 resulted in significant and sustained enhancement in WTh recovery. A similar attenuation of stunning was observed in study IV in six rabbits given intravenous infusion of S-nitroso-N-acetylpenicillamine (SNAP) during occlusion/reperfusion cycles. The magnitude of the protection afforded by NTG and SNAP was comparable to that afforded by the late ischemic PC phase. In contrast, in study III infusion of NTG before occlusion/reperfusion cycles did not enhance WTh recovery, indicating that NTG failed to induce an early PC effect against stunning. This study demonstrates that administration of hemodynamically inactive doses of two unrelated NO donors alleviates myocardial stunning in conscious rabbits, providing direct evidence for a protective action of NO in this setting.

Nitroglycerin induces late preconditioning against myocardial stunning via a PKC-dependent pathway

Previous studies have shown that administration of nitric oxide (NO) donors induces a delayed cardioprotective effect indistinguishable from the late phase of ischemic preconditioning (PC). However, the ability of clinically relevant NO donors to elicit this phenomenon has not been evaluated. In this study we tested whether an NO-releasing agent that is nitroglycerin (NTG), which is widely used clinically, can mimic the late phase of ischemic PC. Four groups of conscious rabbits underwent six cycles of 4-min occlusion (O)/4-min reperfusion (R) for 3 consecutive days (days 1, 2, and 3). The severity of myocardial stunning was assessed as the total deficit of systolic wall thickening (WTh) after the last O/R cycle. In the control group (group I, n = 6), the total deficit of WTh was reduced by 50% and 51% on days 2 and 3 vs. day 1, respectively, indicating late PC against stunning. Pretreatment with NTG (2 microg. kg(-1). min(-1) iv over 1 h) on day 0 (group II, n = 6) was as effective as ischemic PC in mitigating myocardial stunning 24 h later (day 1); on days 2 and 3, no further reduction of stunning was seen. Coadministration of the PKC inhibitor chelerythrine (5 mg/kg) with NTG (group III, n = 6) completely abrogated the NTG-induced protection. Pretreatment with chelerythrine alone (group IV, n = 5) did not alter stunning. These results demonstrate that a relatively brief infusion of NTG induces a robust protective effect against stunning 24 h later via a protein kinase C (PKC)-dependent signaling mechanism. The magnitude of NTG-induced protection is equivalent to that observed during the late phase of ischemic PC. Late PC induced by brief treatment with NTG could be a useful therapeutic strategy for myocardial protection in patients with ischemic heart disease.

PKC-dependent activation of p46/p54 JNKs during ischemic preconditioning in conscious rabbits

A conscious rabbit model was used to study the effect of ischemic preconditioning (PC) on stress-activated kinases [c-Jun NH(2)-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK)] in an environment free of surgical trauma and attending external stress. Ischemic PC (6 cycles of 4-min ischemia/4-min reperfusion) induced significant activation of protein kinase C (PKC)-epsilon in the particulate fraction, which was associated with activation of p46 JNK in the nuclear fraction and p54 JNK in the cytosolic fraction; all of these changes were completely abolised by the PKC inhibitor chelerythrine. Selective enhancement of PKC-epsilon activity in adult rabbit cardiac myocytes resulted in enhanced activity of p46/p54 JNKs, providing direct in vitro evidence that PKC-epsilon is coupled to both kinases. Studies in rabbits showed that the activation of p46 JNK occurred during ischemia, whereas that of p54 JNK occurred after reperfusion. A single 4-min period of ischemia induced a robust activation of the p38 MAPK cascade, which, however, was attenuated after 5 min of reperfusion and disappeared after six cycles of 4-min ischemia/reperfusion. Overexpression of PKC-epsilon in cardiac myocytes failed to increase the p38 MAPK activity. These results demonstrate that ischemic PC activates p46 and p54 JNKs via a PKC-epsilon-dependent signaling pathway and that there are important differences between p46 and p54 JNKs with respect to the subcellular compartment (cytosolic vs. nuclear) and the mechanism (ischemia vs. reperfusion) of their activation after ischemic PC.