[Analysis on incidence of occupational diseases in Guangzhou from 2010 to 2020]

Objective: To analyze the incidence characteristics of occupational diseases in Guangzhou from 2010 to 2020, provide scientific basis for formulating occupational disease prevention and control policies. Methods: In January 2021, based on the data of occupational diseases in Guangzhou reported in the Information Monitoring System of Occupational Diseases and Occupational Health, descriptive epidemiological method was used to analyze the types and characteristics of occupational diseases in Guangzhou from 2010 to 2020. Results: A total of 1341 cases of 38 kinds of occupational diseases in 9 categories were reported in the past 11 years. The incidence of occupational pneumoconiosis, occupational otolaryngology and oral diseases and occupational chemical poisoning ranked the top three, accounting for 38.1% (511/1341) , 30.5% (409/1341) and 16.2% (217/1341) of the total cases respectively. The cases of pneumoconiosis in welders and silicosis accounted for 47.7% (244/511) and 34.4% (176/511) of the cases of occupational pneumoconiosis respectively. The cases of noise deafness accounted for 99.8% (408/409) of occupational otorhinolaryngology oral diseases. Acute occupational chemical poisoning cases accounted for 26.7% (58/217) of the occupational chemical poisoning cases, in which dichloroethane poisoning cases ranked the first, accounting for 79.3% (46/58) . Chronic occupational chemical poisoning cases accounted for 73.3% (159/217) of the occupational poisoning cases, in which benzene and lead poisoning cases ranked the top two, accounting for 79.2% (126/159) and 17.6% (28/159) respectively. Conclusion: Pneumoconiosis, silicosis, noise deafness, benzene poisoning, lead poisoning, dichloroethane poisoning should be supervised and managed as key occupational diseases in Guangzhou.

[Evaluation of immune persistence of vaccine]

The evaluation methods of immune persistence include direct evaluation, indirect evaluation, model prediction, and meta-analysis and so on. Direct evaluation is the gold standard for evaluating the immune persistence of vaccines by quantifying the protective effect of vaccines on the onset and (or) infection of preventable diseases. Indirect evaluation of immune persistence by immunological surrogate indicators is more widely used in practice. In addition, mathematical models and meta-analysis can also be used to evaluate the immune persistence of vaccines. It is of great significance to select the appropriate evaluation method to analyze the immune persistence of the vaccine according to the specific situation.

Interleukin 10 Plays an Important Role in Neonatal Rats with Hypoxic-Ischemia Associated with B-Cell Lymphoma 2 and Endoplasmic Reticulum Protein 29

Interleukin 10 (IL-10) is a synthetic inhibitor of human cytokines with immunomodulatory and anti-inflammatory effects. This study was designed to investigate the expression variation of IL-10 in the multiple sites including cortex, hippocampus, and lung tissues of neonatal hypoxic-ischemic (HI) rats and explore the crucial role of IL-10 in alleviating HI brain damage. In this study, neonatal Sprague-Dawley rats were subjected to the right common carotid artery ligation, followed by 2 h of hypoxia. The expression of IL-10 in the cortex, hippocampus, and lung tissues was measured with immunohistochemistry, real-time quantitative polymerase chain reaction (RT-qPCR), and western blot (WB). Immunofluorescence double staining was performed to observe the localization of IL-10 in neurons and astrocytes. Moreover, not-targeting and targeting IL-10 siRNA lentivirus vectors were injected into the rats of the negative control (NC) and IL-10 group, respectively, and the mRNA levels of B-cell lymphoma 2 (Bcl-2) and endoplasmic reticulum protein 29 (ERp29) were detected by RT-qPCR following IL-10 silence. The results demonstrated that the IL-10 expression was markedly increased after HI and IL-10 were colocalized with neurons and astrocytes which were badly injured by HI insult. In addition, Bcl-2 and ERp29 were remarkably decreased following IL-10 mRNA interference compared with the NC group. Our findings revealed that IL-10 exerted its antiapoptotic and neuroprotective effects by regulating the expression of Bcl-2 and ERp29, indicating that IL-10 may be a promising molecule target for HIE treatment.

Vi4-miR-185-5p-Igfbp3 Network Protects the Brain From Neonatal Hypoxic Ischemic Injury via Promoting Neuron Survival and Suppressing the Cell Apoptosis

Neonatal hypoxic ischemic encephalopathy (HIE) due to birth asphyxia is common and causes severe neurological deficits, without any effective therapies currently available. Neuronal death is an important driving factors of neurological disorders after HIE, but the regulatory mechanisms are still uncertain. Long non-coding RNA (lncRNA) or ceRNA network act as a significant regulator in neuroregeneration and neuronal apoptosis, thus owning a great potential as therapeutic targets in HIE. Here, we found a new lncRNA, is the most functional in targeting the Igfbp3 gene in HIE, which enriched in the cell growth and cell apoptosis processes. In addition, luciferase reporter assay showed competitive regulatory binding sites to the target gene Igfbp3 between TCONS00044054 (Vi4) and miR-185-5p. The change in blood miR-185-5p and Igfbp3 expression is further confirmed in patients with brain ischemia. Moreover, Vi4 overexpression and miR-185-5p knock-out promote the neuron survival and neurite growth, and suppress the cell apoptosis, then further improve the motor and cognitive deficits in rats with HIE, while Igfbp3 interfering got the opposite results. Together, Vi4-miR-185-5p-Igfbp3 regulatory network plays an important role in neuron survival and cell apoptosis and further promote the neuro-functional recovery from HIE, therefore is a likely a drug target for HIE therapy.

A single-nucleotide polymorphism induced alternative splicing in Tacr3 involves in hypoxic-ischemic brain damage

Single-nucleotide polymorphism (SNP) and Alternative splicing (AS) were found to be implicated in certain diseases, nevertheless, the contributions of mRNA SNPs and AS to pathogenesis in developing rat brains with hypoxic-ischemic encephalopathy (HIE) remained largely vague. Additionally, the disease associated with Tacr3 was normosmic congenital hypogonadotropic hypogonadism, while the relationship between HIE and Tacr3 remained largely elusive. The current study was designed to investigate the differentially expressed mRNAs and related SNPs as well as AS in neonatal rats subjected to HIE to identify if the exhibition of AS was associated with SNPs under pathological condition. Firstly, we used postnatal day 7 Sprague-Dawley rats to construct neonatal HIE model, and analyzed the expression profiles of SNP mRNA in hypoxic-ischemic (HI) and sham brains by using RNA sequencing. Then four genes, including Mdfic, Lpp, Bag3 and Tacr3, connecting with HIE and exhibiting SNPs and AS were identified by bioinformatics analysis. Moreover, combined with exonic splicing enhancer (ESE) and alternative splice site predictor (ASSP) analysis, we found that Tacr3 is associated specifically with HIE through 258547789 G > A SNP in inside the Alt First Exon and 258548573 G > A SNP in outside the Alt First Exon. Taken together, our study provides new evidence to understand the role of Tacr3 in HIE and it is possibly a potential target for the treatment of HIE in future clinic trial.

[Retrospective analysis of factors affecting patency rates and causes of failure in use of single-armed two-suture microsurgical vasoepididymostomy]

Objectives: To analyze the factors affecting the patency rate of microsurgical single-stitch longitudinal intussusception vasoepididymostomy and to explore the possible causes of failure. Methods: The clinical data of 87 patients with epididymal obstructive azoospermia who underwent microsurgical vasoepididymostomy from January 2015 to February 2018 in the First Affiliated Hospital of Fujian Medical University were analyzed retrospectively. We observed the patency rate postoperatively and evaluated several factors that possibly related to the patency rates. Preoperative examinations included peripheral blood chromosomes, Y chromosome microdeletions, sex hormones, seminal plasma, etc. After admission, microsurgical single-stitch longitudinal intussusception vasoepididymostomy was performed. During the follow-up, the semen was evaluated to assess the patency rate and the time to patency. Results: The patient's age ranged from 21 to 42 years and the mean age was(25±3) years. Infertility lasted for 1-8 years and the mean infertility time was(2.2±1.1) years. The longitudinal intussusception vasoepididymostomy was successfully completed in 80 patients , 5 cases gave up the anastomosis surgery because of multiple segment obstruction of the vas deferens, complete obstruction of the epididymis or testicular obstruction. Two cases underwent crossed vasovasostomy( sperm was present in the ejaculate in 1 case postoperatively). Of all the patients, 72 were successfully followed up. The follow-up time was 3-29 months, with an average of (12.0±1.7)months. Excluding 3 cases of follow-up time less than 12 months who still had no sperm in the ejaculate, 69 patients' data were in cluded in the final statistics, of which 50 cases with return of sperm in the ejaculate, the overall patency rate was 72.5%(50/69), concentration of sperm was 0.1-137.2 million/ml, and the mean concentration was(29±21) million/ml; with the progressive motile sperm rate ranging from 0-57.9%, the mean rate was(29.9±21.1)%. The patency rates of motile sperm and immobile sperm found in epididymal fluid during surgery were 82.2%(37/45) and 54.2%(13/24), respectively. The patency rate of bilateral and unilateral anastomoses was 77.6%(45/58) and 45.5%(5/11), respectively; the patency rate of caput anastomosis was 47.8%(11/23), and 84.8%(39/46) for corpus or caudal anastomosis. 17 patients achieved natural pregnancy postoperatively, the rate was 34.0%(17/50). Conclusions: The therapeutic effect of microsurgical single-stitch longitudinal intussusception vasoepididymostomy is satisfactory. The motile spermatozoa in epididymal fluid, bilateral surgery and corpus or caudal anastomosis can improve the patency rate postoperatively.

[Analysis of the prevalence and related risk factors of prostate diseases in traffic policemen]

Objective: To investigate the prevalence and related risk factors of prostate diseases in traffic policemen. Methods: A total of 848 traffic policemen who took part in the physical examination among August and September in 2016 were selected as research subjects, and a questionnaire survey was conducted to collect their information including smoking, alcohol drinking, biological and physiological indicators, as well as prostate disease etc. The relationship between the prevalence of prostate diseases and related risk factors was analyzed by Non-conditional Logistic Regression. Results: The total prostate disease prevalence rate was 40.2% in the study subjects, and there is statistical significance (P<0.05) of differences between prostate disease group and non disease group in age, work age, smoking, drinking and field work. Single factor analysis showed that age, work age, smoking, and field work are independent risk factors of prostate disease (P<0.05) . Multivariate Logistic regression analysis showed that increasing age (OR 1.03) , smoking (OR 1.92) and field work time (OR 1.47) significantly increased the risk of prostate disease in male police after age, smoking, drinking, BMI, systolic blood pressure, diastolic blood pressure, fasting blood glucose, blood lipids and other indicators were adjusted. Conclusion: age, smoking and field work time are risk factors of prostate diseases in the traffic police. There is great significance in publicizing the harmful effects of smoking and reducing the duration of field work.

[Effectiveness of transurethral seminal vesiculoscopy in the treatment of persistent hematospermia, and oligoasthenozoospermia and azoospermia from ejaculatory duct obstruction]

Objective: To analyze the effectiveness of transurethral seminal vesiculoscopy in the treatment of persistent hematospermia, and oligoasthenozoospermia and azoospermia from ejaculatory duct obstruction. Methods: The clinical date of 56 cases of persistent hematospermia, or azoospermia/oligoasthenozoospermia from ejaculatory duct obstruction treated with transurethral seminal vesiculoscopy between November 2013 and January 2016 in the First Affiliated Hospital of Fujian Medical University were reviewed. A total of 30 cases were persistent hematospermia for 6 months to 3 years, with no response to routine antibiotic therapy for >4 weeks; 24 cases were obstructive azoospermia; and the other 2 cases were extreme oligoasthenozoospermia. Transrectal ultrasound of the prostate and seminal vesicles, and pelvic magnetic resonance imaging (MRI) were performed before the surgery, finding seminal vesicle dilation in 28 cases, ejaculatory duct dilation in 18 cases, seminal vesicle and ejaculatory duct dilation in 7 cases, seminal vesicle dilation with ejaculatory duct cyst in 2 cases, and bilateral ejaculatory duct dilation with prostatic utricle cyst in 1 case. After the transurethral seminal vesiculoscopy, follow-up examinations were performed to assess the effectiveness of the surgery for ≥3 months. Results: The surgery was successful in all the patients, with the duration of surgery ranging from 30 to 148 minutes. Among the 30 patients with hematospermia, calculi in ejaculatory duct or seminal vesicle was found in 20 cases, while inflammation or dark red jelly-like substances in seminal vesicle was seen in all cases. In the follow-up of 9.7 months (3.0-13.0 months), hematospermia in 26 (26/30, 86.7%)patients was relieved or cured after 1-6 times of ejaculation; the other 4 (4/30, 13.3%)cases still had hematospermia. In postoperative semen analysis for the 24 cases of azoospermia from ejaculatory duct obstruction, sperms were detected in 16(16/24, 66.7%)cases, but sperms were not found after 6 months following the surgery in 1 of the 16 case, thus re-obstruction was suspected; in the other 8 (8/24, 33.3%)cases, sperms could not be found in multiple semen analyses in >12 months after the surgery. The 2 cases of extreme oligoasthenozoospermia had obvious improvement in routine semen analysis in 1 and 3 months after the surgery. Except for 1 case of scrotum swelling after surgery, no postoperative complications (retrograde ejaculation, urinary incontinence, or rectal injury) were observed. Conclusions: Transurethral seminal vesiculoscopy was an effective therapy for persistent hematospermia. More strict operation indication and careful performance are necessary for azoospermia oligoasthenozoospermia from ejaculatory duct obstruction.

A combustion method to synthesize nanoporous graphene

In this paper, we introduce a combustion method which is rapid, low cost, mass-producing and environmentally friendly to produce nanoporous graphene. After loading a graphene oxide aerogel (GOA)/paper (GOP) on a preheated hot plate (as the heat source, with a temperature as low as 200 °C) under an ambient environment, in a few seconds, the GOA/GOP would self-combust and change into reduced graphene oxide (RGO) with nanopores mainly concentrated in the 0.4-2.0 nm range and a large specific surface area of 536 m2 g-1. Supercapacitors fabricated with the synthesized porous RGO (P-RGO) showed a high specific capacitance of 245 F g-1 at 0.1 A g-1, and a retention rate of about 96.9% after 12 000 cycle tests with respect to the initial specific capacitance with a scan rate of 10.0 A g-1. The production yield of this method was as high as 77.0%.

[Influence of collagen/fibroin scaffolds containing silver nanoparticles on dermal regeneration of full-thickness skin defect wound in rat]

Objective: To explore the influence of collagen/fibroin scaffolds containing silver nanoparticles on dermal regeneration of full-thickness skin defect wound in rat. Methods: Eighty-one collagen/fibroin scaffolds containing silver nanoparticles (with the mass concentration of silver nanoparticles as 10 mg/L) and 81 collagen/fibroin scaffolds without silver nanoparticles were produced respectively with freeze-drying method and enrolled as silver nanoparticles scaffold group (SNS) and control scaffold group (CS). Nine scaffolds in each group were cultured with human fibroblasts. At post culture hour (PCH) 2, 12, and 24, the human fibroblasts adherent to the scaffolds (n=3) in two groups were counted. Four full-thickness skin defect wounds were reproduced on the back of each one of the 36 SD rats. The rats were divided into groups SNS (wounds were transplanted with collagen/fibroin scaffolds containing silver nanoparticles) and CS (wounds were transplanted with collagen/fibroin scaffolds without silver nanoparticles) according to the random number table, with 18 rats in each group. In post surgery week (PSW) 1, 2, and 4, 6 rats in each group were sacrificed respectively for general observation, observation of histological structure, inflammatory cell infiltration, and collagen deposition with HE staining, count of CD68 positive cells with immunohistochemical staining, and mRNA expressions of interleukin-6 (IL-6) and IL-10 with real-time fluorescent quantitative reverse transcription polymerase chain reaction. Data were processed with analysis of variance of factorial design, t test, and Bonferroni correction. Results: (1) At PCH 2, 12, and 24, the numbers of human fibroblasts adherent to the scaffolds in the two groups were close (with t values from 1.77 to 2.60, P values above 0.05). (2) In PSW 1, no obvious symptom of infection was observed in wound or wound edge of rats in group SNS with obvious vascularization of scaffolds, while obvious symptoms of infection were observed in wounds of rats in group CS with some scaffolds exfoliated. In PSW 2, the scaffolds were firmly attached to the wounds of rats in group SNS, while obvious contracture was observed in the wounds of rats in group CS with a lot of scaffolds exfoliated. In PSW 4, the scaffolds covered the wounds of rats in group SNS with obvious epithelization on the surface of the scaffolds, while all the scaffolds exfoliated, leaving obvious contracture of residual wounds of rats in group CS. (3) In PSW 1 and 2, compared with those in group CS, more collagen secretion and tissue regeneration and less inflammatory cell infiltration in the scaffolds were observed in the wounds of rats in group SNS. In PSW 4, obvious epithelization was observed in the wounds of rats in group SNS, while inflammatory cell infiltration was observed without obvious epithelization in the wounds of rats in group CS. (4) In PSW 1, the number of CD68 positive cells in the wounds of rats in group SNS [(54±10) /mm(2)] was similar to that in group CS [(78±7) /mm(2,) t=1.52, P>0.05]. In PSW 2 and 4, the numbers of CD68 positive cells in the wounds of rats in group SNS [(154±10) and (77±7) /mm(2)] were significantly less than those in group CS [(268±16) and (136±13) /mm(2,) with t values respectively 7.31 and 3.83, P values below 0.01] respectively. (5) Except for the expression in PSW 4 (t=1.23, P>0.05), the mRNA expressions of IL-6 in the wounds of rats in group SNS in PSW 1 and 2 were significantly lower than those in group CS (with t values respectively 13.12 and 4.65, P values below 0.01). Except for the expression in PSW 1 (t=3.08, P<0.05), the mRNA expressions of IL-10 in PSW 2 and 4 in the wounds of rats in the two groups were similar (with t values respectively 2.14 and 0.49, P values above 0.05). Conclusions: Besides good biocompatibility, collagen/fibroin scaffolds containing silver nanoparticles have obvious effect in modulating inflammation, thus they can accelerate dermal regeneration induced by collagen/fibroin scaffolds for wound repair.

[Investigation on events of bus on fire in 6 years in the mainland of China]

Objective: To retrospectively analyze the characteristics of events of bus on fire in 6 years in the mainland of China. Methods: Events of bus on fire happened between January 2009 and December 2014 were retrieved through Baidu search engine, Chinese Journals Full-text Database, and PubMed database in the search strategy with " bus" and " fire" or " arson" as keywords combined with the name of provinces, autonomous regions, and municipalities of the mainland of China. The occurrence time, region, cause of fire, casualties of each event were recorded, and the correlative analysis was conducted. Data were processed with Microsoft Excel software. Results: Totally 287 events of bus on fire were retrieved, among which 49 events happened in 2009, 36 events happened in 2010, 35 events happened in 2011, 37 events happened in 2012, and respectively 65 events happened in 2013 and 2014. The events of bus on fire most frequently happened in June and July, respectively 49 and 39 events. Among the distribution of occurrence regions of events of bus on fire, there were 78 events (27.18%) in east China, 52 events (18.12%) in northeast China, 41 events (14.29%) both in north China and south China. Among the causes of events of bus on fire, spontaneous combustion of bus ranked in the first (267 events, accounting for 93.03%), followed by arson (13 events, accounting for 4.53%). Among the 13 events of bus on fire caused by arson, 7 events happened between 16: 00 and 20: 00, and 3 events happened between 8: 00 and 10: 00. Totally 27 events of bus on fire (9.41%) were with casualties, among which 13 events (48.15%) were caused by spontaneous combustion of bus, 10 events (37.04%) were caused by arson, and 4 events (14.81%) were caused by traffic accidents. Arson caused the most severe casualties (at least 88 deaths and 287 injuries), followed by spontaneous combustion of bus (at least 35 deaths and 140 injuries) and traffic accidents (at least 9 deaths and 20 injuries). Conclusions: Events of bus on fire happened more frequently in recent years in the mainland of China, and the frequencies were much higher especially in June and July. Most events were caused by spontaneous combustion of bus, followed by arson. Most of the events of bus on fire caused by arson happened in the morning and evening rush hours of urban traffic, and althouth the occurrence rate was not high, the casualties were most severe.

[Advances in the research of acute kidney injury post burn]

Acute kidney injury (AKI), one of the common and important complications post burn, shows a high incidence and mortality in severely burned patients. The common etiologic factors involved in the development of AKI post burn include hypovolaemia, denatured proteins, nephrotoxic agents, etc., while the molecular mechanisms include oxidative stress injury, systematic or local inflammation, apoptosis, and so on. Furthermore, quite a few signaling pathways participate in the regulation of the occurrence and development of AKI post burn. Existed researches on the treatment of AKI post burn focus on the fluid replacement, renal replacement therapy, anti-infection, and specific agents interfering pathophysiologic or molecular mechanisms of AKI. In this review, we summarize the new advances in the research of the occurrence, development, and diagnosis and treatment of AKI post burn.

Effects of Piper sarmentosum extract on the growth performance, antioxidant capability and immune response in weaned piglets

The biological properties of Piper sarmentosum render it a potential substitute for antibiotics in livestock feed. This study evaluated the effects of P. sarmentosum extract (PSE) on the growth performance, antioxidant capability and immune response of weaned piglets. Eighty 21-d-old weaned piglets were selected and randomly allocated to one of four dietary treatments with five replicates of four pigs each. The dietary treatments consisted of a basal diet supplemented with 0 (T0), 50 (T50), 100 (T100) or 200 (T200) mg/kg PSE. The feeding trial lasted 4 weeks. The results revealed that the T50 group had the highest average daily gain (ADG) and average daily feed intake (ADFI) throughout the feeding trial (p < 0.05). Additionally, the T50 group had higher (p < 0.05) serum glutathione peroxidase activity (GSH-Px) and lower (p < 0.05) serum malondialdehyde (MDA) levels than the T0 group at 4 weeks post-weaning (p < 0.05). Serum levels of interleukin-1β (IL-1β) and tumour necrosis factor-α (TNF-α) decreased, while serum levels of interleukin-4 (IL-4), interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) increased by PSE supplementation at 4 weeks post-weaning (p < 0.05). PSE supplementation upregulated the mRNA expression of IL-4, IL-10 and TGF-β and downregulated the mRNA expression of TNF-α, IL-1β and interleukin-6 (IL-6) in the ileal mucosal layer of piglets (p < 0.05). In summary, our study findings revealed that PSE supplementation improved the antioxidant capability, and reduced inflammation, which may be beneficial to weaned piglet health.

Soybean isoflavone reduces the residue of zearalenone in the muscle and liver of prepubertal gilts

The aim of the present study was to evaluate the protective effects of isoflavone (ISO) against zearalenone (ZEA) residues in the muscle and liver tissues of prepubertal gilts. Seventy 75-day-old, prepubertal, female pigs (Duroc × Landrace × Yorkshire, 26.5 ± 0.60 kg) were allocated randomly to seven diet treatments for 21days as follows: one control group (fed the basal diet) and six groups fed the basal diet with the addition of either 0.5 or 2.0 mg/kg ZEA plus either 0, 300 or 600 mg/kg ISO. The results showed that the diet with 2.0 mg/kg ZEA added caused an increase of ZEA residue level in muscle tissue (P < 0.05), and that the addition of both 0.5 and 2.0 mg/kg ZEA increased the residue level of ZEA in the liver of prepubertal gilts (P < 0.05). Addition of 600 mg/kg ISO to 2.0 mg/kg ZEA-contaminated diet decreased the ZEA residue level in liver tissue (P < 0.05), and the addition of 300 or 600 mg/kg ISO to the 2.0 mg/kg ZEA-contaminated diet decreased the residue levels of ZEA in muscle tissue (P < 0.05). Western blot analysis demonstrated that feeding ZEA to prepubertal gilts increased their protein expression of 3α/3β-hydroxysteroid dehydrogenase (HSD; P < 0.05), and that the addition of 300 or 600 mg/kg ISO to the 2.0 mg/kg ZEA-contaminated diet decreased the protein expression of 3α/3β-HSD (P < 0.05), compared with the addition of 2.0 mg/kg ZEA alone. The results demonstrated that muscle and liver tissues retain residual ZEA when pigs are fed a diet contaminated with high concentrations of ZEA, and that the concentration of ZEA in muscle and liver tissues increased with increased amounts of ZEA in the feed. In diets contaminated with high levels of ZEA, the addition of ISO may accelerate the biotransformation and degradation of ZEA and its metabolites, and reduce the residues of ZEA in liver and muscle tissues of prepubertal gilts.

The changes of aquaporin 2 in the graft of acute rejection rat renal transplantation model

AIM

To investigate the significance and changes of Aquaporin 2 (AQP2) in the rat renal graft of acute rejection (AR).

METHODS

Wistar recipients of Spraque-Dawley or Wistar renal grafts were treated with cyclosporine (CsA). Renal grafts were harvested at various times after transplantation for analysis of the levels of AQP2 mRNA and protein of by RT-PCR and immunohistochemistry.

RESULTS

The expression of AQP2 mRNA and protein in the acutely rejecting were grafts significantly decreased (P < 0.05) compared with the control group. But the expression of AQP2 mRNA and protein in the syngeneic grafts (sTX) versus the immunosuppression group (aTX+CsA) showed no difference compared with a control group (P > 0.05). Furthermore, at day 5 and day 7 after transplantation the expressions of AQP2 expression in the allogeneic group (aTX) were decreased significantly compared with day 3 after transplantation (P < 0.05). In addition, there was no remarkable difference at day 5 or 7 after transplantation.

CONCLUSION

AQP2 mRNA and protein expressions were down-regulated during renal transplant acute rejection, which had no relationship to the ischemia reperfusion injury and denervation damage. Furthermore, CsA administration after kidney transplantation blunted this down-regulation (P > 0.05).

Functional roles of intrinsic neurotrophin-3 in spinal neuroplasticity of cats following partial ganglionectomy

This study detected the effects of endogenous neurotrophin-3 (NT-3) on the collateral sprouting derived from the L6 dorsal root ganglion (DRG) after unilateral removal of adjacent DRGs (L1&#x2013;L5 and L7) in cats. Cholera toxin B tracing revealed significant neurite growth from the spared L6 DRG and axonal sprouting in the dorsal column. There was a significant increase in the number of NT-3 and trkC immunopositive neurons as well as in NT-3 protein level in the spared DRG by immunohistochemistry and enzyme-linked immunoadsorbent assay. NT-3 and its mRNA and trkC were located mainly in large- and medium-sized DRG neurons. NT-3 antibody neutralization in vivo and in vitro results in marked reduction in sprouted fibers. These findings point to an important role of NT-3 in neural plasticity at dorsal column axons.

Spatiotemporal changes of NGF, BDNF and NT-3 in the developing spinal cords of embryonic chicken

Spatiotemporal changes of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in the spinal cords of chick embryonic stage day 7 (E7) and day 14 (E14) were examined by using immunohistochemistry and Western blot. Intensive NGF immunoreaction (IR) was detected in the white matter of the spinal cords, while BDNF-IR in perikaryon and neurite, and NT-3-IR in the nucleus and cytoplasm were seen in the neurons of the ventral horn in the gray matter. Comparatively, the expressions for three growth factors have expanded largely into the dorsal horn at E14, and the level of proteins for these growth factors increased significantly in the spinal cords from E7 to E14. Morphological observation showed that the lumbar spinal cords of E7 appeared rectangular, whereas it gave a butterfly shape in the gray matter consisting of the typical ventral horn, dorsal horn and intermediate zone at E14. The present findings indicated that the spatiotemporal changes of NGF, BDNF and NT-3 could be associated to the morphological changes of developing spinal cords, suggesting the possible roles of three growth factors in the development of spinal cords.

Wurtzite GaAs/AlGaAs core-shell nanowires grown by molecular beam epitaxy

We report the growth of GaAs/AlGaAs core-shell nanowires (NWs) on GaAs(111)B substrates by Au-assisted molecular beam epitaxy. Electron microscopy shows the formation of a wurtzite AlGaAs shell structure both in the radial and the axial directions outside a wurtzite GaAs core. With higher Al content, a lower axial and a higher radial growth rate of the AlGaAs shell were observed. Room temperature and low temperature (4.4 K) micro-photoluminescence measurements show a much higher radiative efficiency from the GaAs core after the NW is overgrown with a radial AlGaAs shell.

Role of NGF in spared DRG following partial dorsal rhizotomy in cats

Neuroplasticity occurs in the spinal cord in response to lesions, but less is known about the underlying mechanism. This investigation explored the role of intrinsic NGF in axonal sprouting of dorsal root ganglia (DRG) in cats subjected to unilateral removal of L1-L5, L7-S2 DRG, but leaving the L6 DRG (spared DRG) undamaged. The expression of mRNA and protein for NGF and TrkA increased significantly by using in situ hybridization histochemistry and immunohistochemistry. ELISA assay showed that the level of NGF was up-regulated in the spared DRG, compared to the control side. In vitro studies showed that cultured neurons prepared from DRG explants of cats that received partial ganglionectomy had greater neurite growth compared to those prepared from untreated controls, and that such increase in neurite was not observed in explants from cats that received partial ganglionectomy and NGF antibody treatment. Taken together, the present findings provided crucial evidence that NGF in DRG might be involved in axonal sprouting in deafferentated cats.

Effects of NT-4 gene modified fibroblasts transplanted into AD rats

It is well known that fibroblasts can act as a cell vector to express functional protein, like neurotrophin-4 (NT-4). The present study evaluated the effect of NT-4 gene modified fibroblasts grafted into the hippocampus of AD rat model. AD rats were reproduced by bilateral transection of the hippocampal fimbria-fornix. The transplanted fibroblasts steadily expressed NT-4 proteins at least 2 months after transplantation. This correlated with a significant rescue in the number of cholinergic neurons in the host hippocampus. Morris water maze tests demonstrated significant improvements in learning and memory, especially in rats receiving NT-4-modified fibroblasts. The present results showed that NT-4 gene modified fibroblasts could provide a long-term and steady expression of NT-4, and it significantly improved the behavior of AD rats. These findings should have important clinical applications in providing a long-term NT-4 Secretion for the treatment of AD.

Zinc blende GaAsSb nanowires grown by molecular beam epitaxy

We report the growth of GaAsSb nanowires (NWs) on GaAs(111)B substrates by Au-assisted molecular beam epitaxy. The structural characteristics of the GaAsSb NWs have been investigated in detail. Their Sb mole fraction was found to be about 25%. Their crystal structure was found to be pure zinc blende (ZB), in contrast to the wurtzite structure observed in GaAs NWs grown under similar conditions. The ZB GaAsSb NWs exhibit rotational twins around their [111]B growth axis, with twin-free segments as long as 500 nm. The total volumes of GaAsSb segments with twinned and un-twinned orientations, respectively, were found to be equal by x-ray diffraction analysis of NW ensembles.

Changes in Glial cell line-derived neurotrophic factor expression in the rostral and caudal stumps of the transected adult rat spinal cord

Limited information is available regarding the role of endogenous Glial cell line-derived neurotrophic factor (GDNF) in the spinal cord following transection injury. The present study investigated the possible role of GDNF in injured spinal cords following transection injury (T(9)-T(10)) in adult rats. The locomotor function recovery of animals by the BBB (Basso, Beattie, Bresnahan) scale score showed that hindlimb support and stepping function increased gradually from 7 days post operation (dpo) to 21 dpo. However, the locomotion function in the hindlimbs decreased effectively in GDNF-antibody treated rats. GDNF immunoreactivty in neurons in the ventral horn of the rostral stump was stained strongly at 3 and 7 dpo, and in the caudal stump at 14 dpo, while immunostaining in astrocytes was also seen at all time-points after transection injury. Western blot showed that the level of GDNF protein underwent a rapid decrease at 7 dpo in both stumps, and was followed by a partial recovery at a later time-point, when compared with the sham-operated group. GDNF mRNA-positive signals were detected in neurons of the ventral horn, especially in lamina IX. No regenerative fibers from corticospinal tract can be seen in the caudal segment near the injury site using BDA tracing technique. No somatosensory evoked potentials (SEP) could be recorded throughout the experimental period as well. These findings suggested that intrinsic GDNF in the spinal cord could play an essential role in neuroplasticity. The mechanism may be that GDNF is involved in the regulation of local circuitry in transected spinal cords of adult rats.

Effects of electro-acupuncture on CNTF expression in spared dorsal root ganglion and the associated spinal lamina II and nucleus dorsalis following adjacent dorsal root ganglionectomies in cats

It is well known that plasticity occurs in deafferented spinal cord, and that electro-acupuncture (EA) could promote functional restoration. The underlying mechanism is, however, unknown. Ciliary neurotrophic factor (CNTF) plays a crucial role in neurite outgrowth and neuronal survival both in vivo and in vitro, and its expression might explain some of the mechanism. In this study, we investigated the effects of EA on CNTF expression in the spared L(6) dorsal root ganglion (DRG), and spinal lamina II at spinal segments L(3) and L(6) as well as nucleus dorsalis (ND) of L(3) spinal segment following removal of L(1)-L(5) and L(7)-S(2) (DRG) in the cat. After ganglionectomies, the total and small-to-medium-sized numbers of immunoreactive neurons decreased at 3 dpo, and returned to the sham-operated level as early as 7 dpo. After EA, immunoreactive neurons in L(6) DRG noticeably increased at 7 dpo, compared with the non-acupunctured group. Notable increase in the large neurons was seen at 14 dpo, while their numbers in L(3) and L(6) spinal cord segments significantly declined at 3 dpo. Those in L(3) segment did not reach the sham-operated level until 14 dpo, but their numbers in L(6) segment returned to the sham-operated level as early as 7 dpo. CNTF immunopositive neurons in the ND of L(3) segment returned to the sham-operated level at 14 dpo. After EA, their number significantly increased as early as 7 dpo in lamina II of L(6) segment, and as late as 14 dpo in ND of L(3) segment. Western blot analysis showed CNTF changes corresponding to those shown in immunohistochemical staining. It is concluded that CNTF expression was involved in the EA promoted plastic changes in L(6) DRG and the associated deafferented spinal lamina and ND.

Effects of engrafted neural stem cells derived from GFP transgenic mice in Parkinson's diseases rats

This study evaluated the therapeutic effect of neural stem cells (NSCs) transplanted into Parkinson's disease (PD) rats. NSCs were identified in vitro, then engrafted into the striatum of the PD rats. The rotational behavior was evaluated 1, 2, 4 and 6 weeks. A significant rotational behavior improvement was observed in PD rats subjected to cell transplantation. Transplanted NSCs not only express Nerve growth factor and Neurotrophin-3 in vitro, but also survive and partly differentiate into tyrosine hydroxylase (TH) positive cells in vivo. The results show that NSCs could be effective for PD treatment and the mechanisms might involve the neurotrophin expression and the neural differentiation.

Nondipole effects in the photoionization of xe 4d5/2 and 4d3/2: evidence for quadrupole satellites

Measurements of nondipole parameters in spin-orbit-resolved Xe 4d photoionization demonstrate dynamical differences arising from relativistic effects. The experimental data do not agree with relativistic random-phase approximation calculations of single ionization dipole and quadrupole channels. It is suggested that the discrepancy is due to the omission of multiple-excitation quadrupole channels, i.e., quadrupole satellite transitions.

Absolute measurements and theoretical calculations of photoionization cross sections along the isonuclear sequence of multiply charged barium ions

Photoionization of multiply charged ions of the Ba isonuclear sequence up to Ba6+ has been studied in a beam-beam experiment. A very strong increase in the resonance structures was observed when moving from Ba2+ to Ba6+. Absolute values of the photoionization cross sections were measured for Ba2+ and Ba3+ ions. The interpretation of the results is provided using theoretical multiconfiguration Dirac-Fock and relativistic random phase approximation calculations, showing that the collapse of the nf orbitals occurs for Ba4+.

K-shell photodetachment of Li(-): experiment and theory

An experimental K-shell photodetachment study of Li(-) giving rise to doubly photoionized Li(+) ions has been carried out at the Advanced Light Source, using a collinear photon-ion beam apparatus. The experiment reveals dramatic structure, differing substantially both qualitatively and quantitatively from the corresponding processes above the 1s ionization threshold in Li and Li(+), as predicted by our enhanced R-matrix calculation. The experimental/theoretical comparison shows good agreement over some of the photon energy range, and also reveals some puzzling discrepancies.

Effects of methylprednisolone and aprotinin on phospholipase D activity of leukocytes in systemic inflammatory response induced by cardiopulmonary bypass

AIM

To investigate the role of leukocyte phospholipase D (PLD) in systemic inflammatory response induced by cardiopulmonary bypass (CPB) and the effects of methylprednisolone and aprotinin on leukocyte PLD activity.

METHODS

Forty-two patients who received CPB open heart surgery were divided into 3 groups: methylprednisolone group, aprotinin group, and control group. Arterial blood (10 mL) was collected for assay of leukocyte PLD activity, myeloperoxidase (MPO) activity, and CD11b expression at 8 different time points in perioperative period. Plasma IL-6, IL-8, and C-reactive protein levels were also determined.

RESULTS

At the time point of ascending aorta declamped, leukocyte PLD activity for control group was (18 +/- 8) nmol choline . h-1 . mg-1, which was higher than that of pre-CPB (P < 0.01); the PLD activity for methylprednisolone group was (10 +/- 6) nmol choline . h-1 . mg-1 that was lower than control (P < 0.05), while it had no statistical difference compared with that of pre-CPB. In methylprednisolone group, PLD activity elevation was postponed to the time point of CPB stopped. There was no statistical difference in PLD activity between aprotinin group and control (P > 0.05). After administration of methylprednisolone or aprotinin, leukocyte CD11b expression, plasma IL-6, IL-8, C-reactive protein levels, and MPO activity decreased by different extent.

CONCLUSION

Leukocyte PLD activity was elevated significantly in systemic inflammatory response induced by CPB and methylprednisolone partially blunted the CPB-induced inflammatory response by inhibiting PLD activity.

[Role of phospholipase D in phagocytosis and exocytosis]

Mammalian phospholipase D(PLD) is a very important enzyme in the cellular signalling pathways. More and more lines of evidences suggest that PLD may be pivotal on multiple specialized steps in receptor-mediated phagocytosis and exocytosis. In this review, we will explore the recent advances on the role and the mechanism of PLD in phagocytosis and exocytosis.

Does aluminum inhibit pollen germination via extracellular calmodulin?

The effect of aluminum (Al) on pollen germination and its mechanism of action were investigated. Pollen germination and pollen tube elongation were inhibited by Al at pH 4.5. This inhibitory effect was reversed by the addition of purified calmodulin (CaM), whereas neither the calcium binding-protein S-100 nor Al chelator citric acid at the same concentrations had any obvious effect on Al-inhibited pollen germination. The presence of either the membrane-impermeable CaM inhibitor anti-CaM antiserum or Ca2+ chelator EGTA completely suppressed the effect of exogenous CaM. These results indicate the involvement of extracellular calmodulin in the short-term effects of Al on pollen germination and pollen tube elongation.

Angle-resolved photoelectron spectrometry studies of the autoionization of the 2s(2)2p 2P triply excited state of atomic lithium: experimental results and R-matrix calculations

We have measured the angle-resolved energy dependence of the electrons emitted over the energy range of the triply excited 2s(2)2p 2P lithium resonance using synchrotron radiation. We have also calculated the behavior of the angular distribution parameter beta using the R-matrix approximation. Experimental and theoretical results are in good agreement and show deep minima in the 1s2p (1, 3)P ionic channels. The energy at which the minima occur does not coincide with the resonance energy, but is shifted towards higher energy.

[Phospholipase D and inflammation]

Phospholipase D (PLD) is widely distributed in mammalian cells, where it is regulated by a variety of extracellular signals. Its major substrate is phosphatidylcholine (PC), which is hydrolyzed to phosphatidic acid (PA) and choline. The PLD-catalysed PC hydrolysis is believed to be an important mechanism of signal transduction in cells. More and more lines of evidence indicate that PLD is tightly involved in inflammation. This review introduces the recent advances of PLD in respiratory burst, degranulation and arachidonic acid release.

[Rolipram reversed salbutamol tolerance in guinea pig trachea]

Studies were carried out to examine the role of phosphodiesterase(PDE) III and PDE IV in the development of tachyphylaxis of isolated guinea pig trachea to beta 2 adrenoceptor agonists. Treating trachea with salbutamol(SB) 1 mumol.L-1 for 1 h produced a 5-fold rightward shift of the SB concentration-response curve for the spasmolytic effect against methacholine-induced bronchocontraction and decreased the maximum SB-induced relaxation by 30%, i.e. induced tolerance of airway response of SB in vitro. The PDE IV inhibitor rolipram (Rol, 1 mumol.L-1, IC50), but not the PDE III inhibitor siguazodan (SK&F 94836, 1 mumol.L-1, IC50), reversed the SB tolerance. However, the protein synthesis inhibitor cycloheximide(10 mumol.L-1) did not abolish the SB tolerance. These results indicate that the SB tolerance may be related to increase in PDE IV activity.

Calbindin-containing non-specific thalamocortical projecting neurons in the rat

Immunoreactivity for calcium binding proteins was used to demonstrate the neurochemical profiles of non-specific thalamocortical neurons located in the ventromedial nucleus, the centrolateral nucleus, and the nucleus reuniens that project to the somatosensory cortex in the adult rat. Cortical injections of fluorescent tracers combined with immunohistochemistry for calcium binding proteins revealed that retrogradely labeled neurons in these three thalamic nuclei are immunoreactive for calbindin. The present results suggest the presence of a chemically distinct non-specific thalamocortical system which terminates in the neocortex.

Salbutamol up-regulates PDE4 activity and induces a heterologous desensitization of U937 cells to prostaglandin E2. Implications for the therapeutic use of beta-adrenoceptor agonists

Previous studies with U937 cells, a human monocyte cell line, have shown that the activity of cyclic nucleotide phosphodiesterase 4 (PDE4) is increased by agents that elevate cyclic AMP content. The present experiments were conducted to determine 1) whether an increase in PDE4 steady-state message and/or protein accompanies the up-regulation of PDE4 activity and 2) whether the up-regulation changes the functional responses of U937 cells to activators of adenylyl cyclase. To up-regulate PDE4 activity, U937 cells were treated for 4 h with a combination of 1 microM salbutamol, a beta-adrenoceptor agonist, and 30 microM rolipram, a PDE4 inhibitor. Cells were washed extensively to remove drugs and used immediately in various experimental protocols. Reverse transcriptase-polymerase chain reactions conducted with primers specific for the four PDE4 subtypes suggested that pretreatment with salbutamol and rolipram increased steady-state mRNA levels of PDE4A and PDE4B, but not PDE4C or PDE4D. Immunoblot analyses using two rabbit polyclonal antibodies, one directed against human recombinant PDE4A and PDE4D and a second directed against human recombinant PDE4B, revealed bands of immunoreactivity corresponding to approximately 125 kDa (PDE4A) and approximately 70 kDa (PDE4B), respectively, that increased in intensity after cells were treated with salbutamol and rolipram. As demonstrated in both time course and concentration-response studies with prostaglandin E2 (PGE2), an agent that activates adenylyl cyclase by a non-beta-adrenoceptor-mediated mechanism, cAMP accumulation was substantially decreased in cells in which PDE4 activity had been up-regulated. The difference in PGE2-stimulated cAMP accumulation between control and PDE4 up-regulated cells was greatly reduced in the presence of rolipram, consistent with the notion that an increase in PDE4 activity was responsible for the heterologous desensitization. Functionally, up-regulation of PDE4 markedly decreased the ability of PGE2 to inhibit LTD4-induced Ca2+ mobilization in intact cells. A hypothetical implication of these results is that increasing PDE4 activity in vivo by administering beta-adrenoceptor agonists could exacerbate inflammatory processes by decreasing the activity of endogenous anti-inflammatory agents such as PGE2.

[Progress in the study of cyclic nucleotide phosphodiesterases]

There are five families of cyclic nucleotide phosphodiesterase isozymes, which have a common structure, but have different biochemical characteristics, physiologic functions and regulatory mechanisms. Various selective phosphodiesterase inhibitors may have potential uses for antiasthmatic, inotropic, vasodilative, antithrombotic and antidepressant drugs.

Colforsin or imidazolidione potentiates cAMP elevation caused by endothelin-1 in rat aorta

Endothelin-1 (ET-1) caused slow-developing and stable vasoconstrictions in isolated rings of rat thoracic aortae with a pD2 value of 7.55 +/- 0.10 compared to pD2 values of 9.30 +/- 0.10 and 8.36 +/- 0.30 for angiotensin II and norepinephrine, respectively. Although the potency of ET-1 was somewhat lower than those of norepinephrine and angiotensin II, the maximal tension generated by ET-1 was comparable to that of norepinephrine and considerably greater than that of angiotensin II. Incubation of aortic rings in the absence of extracellular Ca2+ or in the presence of the Ca2+ channel blocker nifedipine (100 nmol.L-1) greatly attenuated ET-1-induced vasoconstriction. ET-1 (20 nmol.L-1, approximately the ED50 for vasoconstrictions) also caused elevation of cAMP levels in aortic rings after 15 and 25 min of exposure. The cAMP phosphodiesterase inhibitor imidazolidione (Imi, Ro 20-1724, 100 mumol.L-1) potentiated the cAMP responses to ET-1. Rings incubated for 25 min with ET-1 (20 nmol.L-1) showed much larger cAMP elevations caused by colforsin (Col, forskolin 1 mumol.L-1), a direct adenylate cyclase activator and potentiator, than with Col or ET-1 alone. Therefore, ET-1 may utilize at least 2 signal transduction mechanisms, one involving the opening of nifedipine-sensitive Ca2+ channels and the other involving the elevation of cAMP levels, to produce the unusually slow-developing and stable vasoconstrictions in rat aortae.

Association between leukotriene B4-induced phospholipase D activation and degranulation of human neutrophils

We have explored the role of phospholipase D (PLD) activation in leukotriene B4 (LTB4)-induced Ca2+ mobilization and degranulation of human neutrophils. Stimulation of [3H]alkyl-acyl-phosphatidylcholine-labeled neutrophils with LTB4 resulted in a rapid accumulation of [3H]alkyl-phosphatidic acid (PA) as well as a somewhat slower accumulation of [3H]alkyl-diglyceride (DG). In the presence of ethanol, PLD catalyzed a transphosphatidylation reaction in which LTB4 increased [3H]alkyl-phosphatidylethanol formation and simultaneously decreased LTB4-induced PA and DG accumulation. This pattern of lipid metabolism is consistent with the conclusion that LTB4 stimulates PLD activity in human neutrophils. Additional studies in which the extracellular and intracellular concentrations of Ca2+ were varied indicated that maximal LTB4-induced PLD activation was dependent upon Ca2+ and potentiated by inhibitors of protein kinase C. The time-course and concentration-response curves for LTB4-induced PLD activation were different from those for LTB4-induced Ca2+ mobilization, as measured by fura-2 fluorescence. On the other hand, the concentration-response curve for LTB4-induced PLD activation was similar to that for LTB4-induced degranulation. Preincubation of the cells with ethanol inhibited LTB4-induced PA and DG accumulation, as well as degranulation, suggesting that one or both of these metabolites were important for this response. In contrast, ethanol had no effect on LTB4-induced Ca2+ mobilization. Propranolol, an inhibitor of phosphatidate phosphohydrolase, abolished DG accumulation in response to LTB4 but had no effect on degranulation, suggesting that PA is more important than DG as a mediator of degranulation. Taken collectively, these data indicate that LTB4-induced activation of PLD in human neutrophils is mediated by a Ca(2+)-dependent mechanism, but not by protein kinase C. In addition, PLD activation in these cells may induce degranulation, but not Ca2+ mobilization.

Stimulation of beta adrenoceptors in a human monocyte cell line (U937) up-regulates cyclic AMP-specific phosphodiesterase activity

Experiments were conducted using undifferentiated U937 cells, a human monocytic cell line, to establish an in vitro model to examine the hormonal regulation of the cyclic AMP (cAMP)-specific phosphodiesterase (PDE IV). Standard chromatographic techniques, coupled with the use of inhibitors and activators that are selective for various phosphodiesterase (PDE) isozymes, were used to establish the PDE isozyme profile in supernatant fractions of U937 cells. When PDE activity was assessed using 1 microM [3H]cAMP as a substrate, 70 to 90% of the total U937 cell supernatant activity in the major peak eluting from anion-exchange columns was inhibited by 30 microM rolipram, a selective inhibitor of PDE IV. The remaining activity was nearly abolished by 10 microM siguazodan or 10 microM cyclic GMP (cGMP,) selective inhibitors of the cGMP-inhibited PDE. Kinetic analyses of the enzyme activity contained within this major peak of PDE activity revealed a cAMP Km = 3 microM and a rolipram Ki = 0.5 microM, values characteristic of PDE IV. Additional studies revealed the presence of a small amount of Ca++/calmodulin-stimulated PDE, but no cGMP-stimulated PDE or cGMP-specific PDE activity. In an effort to induce PDE activity in intact U937 cells by producing a sustained increase in cAMP content, cells were treated for 4 hr with salbutamol (1 microM), rolipram (30 microM) or a combination of both agents. The combination of salbutamol and rolipram produced a 2- to 3-fold increase in PDE activity in U937 cells; when used alone, rolipram was without effect whereas salbutamol induced an increase that was approximately one-half of that observed with the combination. Isozyme isolation and characterization revealed that the overall elevation of cellular PDE activity could be accounted for by a 2- to 3-fold increase in the Vmax of PDE IV with no change in its Km. The induction of PDE IV by salbutamol was: 1) concentration- and time-dependent; 2) detectable only after prolonged (2-4 hr) agonist exposure; 3) preceded by an increase in cAMP content and an activation of cAMP-dependent protein kinase; 4) mimicked by 8-bromo-cAMP and prostaglandin E2; 5) reversible within 3 hr of salbutamol removal; and 6) abolished by cycloheximide or actinomycin D. Collectively, these results indicate that the major PDE isozyme in the soluble fraction of U937 cells is PDE IV and that the activity of this enzyme is increased markedly in cells after prolonged exposure to agents that increase cAMP content.

Agonist-related differences in the relationship between cAMP content and protein kinase activity in canine trachealis

We investigated the relationships between relaxation, cyclic AMP (cAMP) accumulation and cAMP-dependent protein kinase (cAMP-PK) activity in canine tracheal smooth muscle. In time course and concentration-response studies, forskolin and isoproterenol elicited relaxation of isolated trachealis strips that was accompanied by an increase in cAMP content and an activation of cAMP-PK. Although these results were consistent with the proposal that cAMP is a second messenger mediating relaxation of airway smooth muscle, close inspection of the data revealed a discrepancy in the relationship between cAMP accumulation and relaxation. To induce equivalent degrees of tracheal relaxation, forskolin generated greater increments in cAMP accumulation than did isoproterenol. On the other hand, the activation state of cAMP-PK correlated reasonably well with relaxation regardless of which agonist was used. Further analysis of the data revealed that the apparent disparity between cAMP accumulation and relaxation could largely be explained at the level of the relationship between cAMP content and cAMP-PK activity: compared to isoproterenol, forskolin induced greater increases in cAMP accumulation to achieve the same activation state of cAMP-PK. These observations lend support to the proposal that in canine trachealis, various components of the cAMP/cAMP-PK cascade exist in distinct subcellular compartments such that not all of the cAMP generated in response to forskolin has access to its target enzyme, cAMP-PK.

Calcitonin gene-related peptide (CGRP)-induced cyclic AMP, cyclic GMP and vasorelaxant responses in rat thoracic aorta are antagonized by blockers of endothelium-derived relaxant factor (EDRF)

The mechanism of CGRP-induced vasodilation in rat thoracic aorta was investigated using antagonists of the classical endothelium-derived vasorelaxant factor (EDRF) and comparisons with acetylcholine-induced vasodilations. The CGRP-induced relaxations of isolated rings of rat thoracic aorta were completely dependent on the presence of endothelium and were associated with increases in the levels of both cyclic AMP and cyclic GMP, the same as in our previous study using rat abdominal aorta. Maximum relaxations to CGRP, which represented 40-50% reversal of the norepinephrine-induced contractions, occurred with 100 nM CGRP. Addition of acetylcholine (ACh, 1 microM) to aortic rings, which were already maximally relaxed to CGRP, caused further relaxation to 100%, suggesting that CGRP may use a mechanism (or pool of EDRF) different from that of ACh. Both CGRP- and ACh-induced relaxations of aorta were significantly inhibited by the EDRF blocking agents, hemoglobin (10 microM), methylene blue (10 microM), and nordihydroguaiaretic acid (NDGA, 10 microM). In fact, hemoglobin and NDGA were more effective as inhibitors of CGRP-induced relaxations than ACh-induced relaxations. Hemoglobin, methylene blue and NDGA also inhibited the CGRP-induced increases in both cyclic AMP and cyclic GMP levels. On the other hand, indomethacin, a cyclo-oxygenase inhibitor, did not alter CGRP-induced vasorelaxations or increases in either cyclic AMP or cyclic GMP levels, suggesting that prostaglandins are not involved. Therefore, CGRP-induced vasodilations in rat thoracic aorta appear to involve EDRF, leading to cyclic GMP elevations in smooth muscle and ultimately vasorelaxations. However, another previously undescribed mechanism, which involves EDRF-dependent and indomethacin-resistant elevations of cyclic AMP levels, is triggered by CGRP in thoracic aorta. This novel EDRF-dependent cyclic AMP response may contribute to the CGRP-induced vasodilation in rat thoracic aorta.

Relationship between cyclic guanosine monophosphate accumulation and relaxation of canine trachealis induced by nitrovasodilators

The role of cyclic GMP (cGMP) in mediating relaxation of canine trachealis produced by nitrovasodilators (NVDs), compounds that activate guanylate cyclase, was examined. Sodium nitroprusside (SNP) produced a concentration-dependent relaxation of the canine trachealis that was accompanied by a concentration-related increase in cGMP content. In time course studies, relaxation of isolated trachealis strips induced by 30 microM SNP was paralleled by an increase in cGMP that reached a maximum of 18-fold above basal levels within 2 min. Zaprinast, an inhibitor of the cGMP-specific phosphodiesterase, potentiated both SNP-induced relaxation and cGMP accumulation. A cell-permeable analog of cGMP, 8-bromo-cGMP, mimicked the relaxant effects of SNP. Also assessed were the effects of methylene blue, an agent that inhibits soluble guanylate cyclase activity, and hemoglobin, an agent that competitively binds NO-containing compounds. In these experiments, tissues were pretreated with the above agents for 10 min, contracted with 1 or 3 microM methacholine, and then relaxed by the cumulative addition of SNP or two other NVDs, S-nitroso-N-acetyl-penicillamine (SNAP) and glyceryl trinitrate (GTN). Tissues were flash-frozen after adding the final concentration of the various NVDs and assayed for cGMP. Methylene blue and hemoglobin suppressed both cGMP accumulation and relaxation in response to SNAP and GTN. in contrast, methylene blue and hemoglobin inhibited SNP-induced cGMP accumulation but, paradoxically, potentiated SNP-induced relaxation. The results of this study generally support a role for cGMP in NVD-induced relaxation of airway smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)