[Fetal cardiac intervention and perioperative management of fetus with hypoplastic right heart syndrome].

Objective: To summarize the experience of perioperative management strategy of fetal pulmonary valvuloplasty (FPV) for hypoplastic right heart syndrome (HRHS). Methods: In the retrospective study of perioperative data, 13 fetuses of HRHS were treated with FPV in Qingdao Women and Children's Hospital from July 2018 to June 2019. Results: (1) The evaluation indexes of the right ventricle in 13 fetuses before FPV: the mean ratio of tricuspid/mitral annulus, right/left ventricular length, pulmonary/aortic annulus, and tricuspid inflow time/cardiac cycle were 0.81±0.04, 0.56±0.14, 0.69±0.06, and 0.35±0.03, respectively. (2) All pregnant mothers underwent general anesthesia. The basic fetal heart rate was (156±12) beats per minutes before FPV, and 9 fetuses showed bradycardia during the operation, and recovered to normal after drug resuscitation. On the first day after FPV, two cases had bradycardia and pregnancy was terminated. The fluctuation of systolic blood pressure of pregnant mother was less than 20%, and there was no significant difference between preoperative and intraoperative pulse pressure [(36.0±5.6) vs (35.8±6.9) mmHg (1 mmHg=0.133 kPa); t=8.102, P=0.951]. (3) All cases of HRHS fetus successfully underwent FPV. The average gestational age was (27.3±0.8) weeks. The average operation time was (23.2±1.0) minutes. The ratio of tricuspid to mitral annulus (t=-2.513, P=0.022) and the ratio of right to left ventricular length (t=-3.373, P=0.003) were significantly improved at 6 weeks postoperatively. Ten fetuses were delivered, and there was no death after early intervention. (4) Of 13 pregnant women, 3 cases were nausea and vomiting on the day of FPV operation, the treatment of the symptoms was improved by tropisetron; one case had tolerable abdominal pain and improved without special treatment. Pregnant women had no major complications such as cardiac failure, abortion and death. (5) Chromosome karyotype analysis and microarray analysis of amniotic fluid was retained during the operation. No typical chromosome abnormality or other abnormal genetic diagnosis was found. Conclusions: FPV colud be used as an effective intervention measure to promote the development of right ventricle in HRHS fetuses. The scientific management of multidisciplinary professional technical team in perioperative period is particularly important to ensure the success of FPV and the safety of pregnant women and fetuses.

[Investigation of pregestational diabetes mellitus in 15 hospitals in Guangdong province].

Objective: To investigate the morbidity, diagnostic profile and perinatal outcome of pregestational diabetes mellitus (PGDM) in 15 hospitals in Guangdong province. Methods: A total of 41 338 women delivered in the 15 hospitals during the 6 months, 195 women with PGDM (PGDM group) and 195 women with normal glucose test result (control group) were recruited from these tertiary hospitals in Guangdong province from January 2016 to June 2016. The morbidity and diagnostic profile of PGDM were analyzed. The complications during pregnancy and perinatal outcomes were compared between the two groups. In the PGDM group, pregnancy outcomes were analyzed in women who used insulin treatment (n=91) and women who did not (n=104). Results: (1) The incidence of PGDM was 0.472%(195/41 338). Diabetes mellitus were diagnosed in 59 women (30.3%, 59/195) before pregnancy, and 136 women (69.7%,136/195) were diagnosed as PGDM after conceptions. Forty-six women (33.8%) were diagnosed by fasting glucose and glycohemoglobin (HbA1c) screening. (2) The maternal age, pre-pregnancy body mass index (BMI) , prenatal BMI, percentage of family history of diabetes, incidence of macrosomia, concentration of low density lipoprotein were significantly higher in PGDM group than those in control group (all P<0.05). Women in PGDM group had significantly higher HbA1c concentration ((6.3±1.3)% vs (5.2±0.4)%) , fasting glucose [(6.3±2.3) vs (4.8±1.1) mmol/L], oral glucose tolerance test (OGTT) -1 h glucose ((12.6±2.9) vs (7.1±1.3) mmol/L) and OGTT-2 h glucose [(12.0±3.0) vs (6.4±1.0) mmol/L] than those in control group (P<0.01). (3) The morbidity of preterm births was significantly higher (11.3% vs 1.0%, P<0.01), and the gestational age at delivery in PGDM group was significantly smaller [(37.6±2.3) vs (39.2±1.2) weeks, P<0.01]. Cesarean delivery rate in the PGDM group (70.8% vs 29.7%) was significantly higher than the control group (P<0.01). There was significantly difference between PGDM group and control in the neonatal male/female ratio (98/97 vs 111/84, P=0.033). The neonatal birth weight in PGDM group was significantly higher ((3 159±700) vs (3 451±423) g, P<0.01) . And the incidence of neonatal hypoglycemia in the PGDM group was higher than the control group (7.7% vs 2.6%, P=0.036). (4) In the PGDM group, women who were treated with insulin had a smaller gestational age at delivery [(36.9±2.9) vs (37.9±2.5) weeks, P<0.01], and the neonates had a higher neonatal ICU (NICU) admission rate (24.2% vs 9.6%, P<0.01). Conclusions: The morbidity of PGDM in the 15 hospitals in Guangdong province is 0.472%. The majority of PGDM was diagnosed during pregnancy; HbA1c and fasting glucose are reliable parameters for PGDM screening. Women with PGDM have obvious family history of diabetes and repeated pregnancy may accelerate the process of diabetes mellitus. Women with PGDM have higher risk for preterm delivery and neonatal hypoglycemia. Unsatisfied glucose control followed by insulin treatment may increase the need for NICU admission.

A pulmonary tuberculosis outbreak in a long-term care facility.

In long-term care facilities (LTCFs), the elderly are apt to be infected because those with latent tuberculosis infections (LTBIs) are at an increased risk for reactivation and post-primary TB disease. We report an outbreak of TB in staff and residents in a LTCF. An outbreak investigation was conducted after two TB cases were reported from the LTCF. A tuberculin skin test (TST), bacteriological examination and chest radiograph were administered to all facility staff and residents. An outbreak is defined as at least two epidemiologically linked cases that have identical Mycobacterium tuberculosis genotype isolates. This outbreak infected eight residents and one staff member, who were confirmed to have TB in a LTCF between September 2011 and October 2012. Based on the Becker method, the latent and infectious periods were estimated at 223·6 and 55·9 days. Two initial TST-negative resident contacts were diagnosed as TB cases through comprehensive TB screening. Observing elderly people who have a negative TST after TB screening appears to be necessary, given the long latent period for controlling a TB outbreak in a LTCF. It is important to consider providing LTBI treatment for elderly contacts.

Spinal cord injury and Parkinson's disease: a population-based, propensity score-matched, longitudinal follow-up study.

OBJECTIVES: To investigate whether patients with spinal cord injury (SCI) are at an increased risk of developing Parkinson's disease (PD). STUDY DESIGN: A population-based, propensity score-matched, longitudinal follow-up cohort study. SETTING: The study was conducted using the National Health Insurance (NHI) Research Database. METHODS: A total of 10 125 patients with at least 2 ambulatory visits with a diagnosis of SCI in 2001 were enrolled in the SCI group. The non-SCI group comprised 10 125 propensity score-matched patients without SCI. The propensity scores were computed using a logistic regression model that included age, sex, comorbidities and socioeconomic status. The PD-free survival rates of the two groups were estimated using the Kaplan-Meier method. Stratified Cox proportional hazard regression was used to estimate the effect of SCI on subsequent occurrence of PD. RESULTS: During the 3-year follow-up period, 99 subjects in the SCI group and 59 in the non-SCI group developed PD. The hazard ratio of PD for the SCI group compared with the non-SCI group was 1.65 (95% confidence interval 1.16-2.33, P=0.0049). The PD-free survival rate for the SCI group was lower than that for the non-SCI group (P=0.0017). CONCLUSIONS: This study shows that SCI is associated with a subsequent increased risk of PD. Further studies are needed to elucidate the mechanism underlying this association.

Dermatomyositis is associated with an increased risk of cardiovascular and cerebrovascular events: a Taiwanese population-based longitudinal follow-up study.

BACKGROUND: While the chronic inflammation related to autoimmune diseases is known to be associated with an increased cardiovascular risk, much less is known about cerebrovascular risks. OBJECTIVES: The present population-based, age- and sex-matched follow-up study was undertaken to investigate the risks of acute myocardial infarction (AMI) and ischaemic stroke in patients with dermatomyositis (DMS). METHODS: In total 907 patients with DMS were enrolled and compared with a non-DMS control group consisting of 4535 age- and sex-matched, randomly sampled subjects without DMS. The AMI-free and ischaemic stroke-free survival curves were generated using the Kaplan-Meier method. Cox proportional hazard regression was used to estimate the DMS-associated risks of AMI and ischaemic stroke. RESULTS: During the 2-year follow-up period, 14 patients with DMS (1.5%) and 18 patients in the non-DMS control group (0.4%) suffered AMIs. The crude hazard ratio (HR) for suffering an AMI in patients with DMS compared with subjects in the non-DMS group was 3.96 [95% confidence interval (CI) 1.97-7.96, P = 0.0001], while the adjusted HR was 3.37 (95% CI 1.67-6.80, P = 0.0007), after taking into account demographic characteristics and cardiovascular comorbidities. During the same follow-up period, 46 patients (5.1%) and 133 subjects in the control group (2.9%) developed ischaemic strokes. The crude HR for developing an ischaemic stroke in patients with DMS compared with subjects in the non-DMS group was 1.78 (95% CI 1.27-2.49, P = 0.0007), and the adjusted HR was 1.67 (95% CI, 1.19-2.34, P = 0.0028). CONCLUSIONS: These findings suggest that DMS is associated with an increased risk of cardiovascular and cerebrovascular events.

[Efficacy of transcatheter pulmonary valve perforation in neonates with pulmonary atresia with intact ventricular septum].

Objective: To explore the efficacy and safety of transcatheter pulmonary valve perforation in the treatment of neonatal pulmonary atresia with intact ventricular septum (PA-IVS). Methods: The clinical data on surgical treatment and follow-up in 16 patients with PA-IVS who underwent transcatheter pulmonary valve perforation in Women and Children's Hospital, Qingdao University from October 2018 to October 2021 were analyzed retrospectively. The right ventricular systolic pressure and percutaneous oxygen saturation (SpO2) were compared before and after operation. In addition, the SpO2 and echocardiographic data at preoperative and the last follow-up were compared. Comparisons between groups were performed using paired-samples t test. Results: Among the 16 patients (10 males and 6 females) with the age at operation of 19 (14, 26) days, 12 cases underwent transcatheter pulmonary valve perforation successfully, 2 cases were transferred to surgery department for open-heart pulmonary valvulotomy, and the remaining 2 cases were transmitted to surgery department for transthoracic pulmonary valve perforation. The age at operation of the 12 patients who underwent transcatheter pulmonary valve perforation was 18 (14, 27) days, and the weight was (3.6±0.4) kg. The immediate postoperative right ventricular systolic pressure decreased significantly ((57±16) vs. (95±19) mmHg (1 mmHg=0.133 kPa), t=7.49, P<0.001), and the postoperative SpO2 was improved effectively (0.90±0.48 vs.0.75±0.09, t=-5.61, P<0.001). The follow-up time was 22 (7, 33) months for 12 patients who underwent transcatheter pulmonary valve perforation successfully. At the last follow-up, the ratio of right to left ventricular transverse diameter was significantly higher than that before operative (0.55±0.05 vs. 0.45±0.05, t=-3.27,P=0.007). Furthermore, the Z-scores of pulmonary valvular diameter (-0.78±0.23 vs. -1.73±0.56, t=-8.52, P<0.001) and the tricuspid valvular diameter (-0.52±0.12 vs. -1.46±0.38, t=-10.40, P<0.001) were all significantly higher than preoperative data. At last, all the patients achieved biventricular circulation without death or major complications. Conclusion: Transcatheter pulmonary valve perforation is a safe and effective therapy for neonatal PA-IVS, and its curative effect has been confirmed by the medium follow-up data.

[Interim follow-up of fetal cardiac intervention in five fetuses with pulmonary atresia with intact ventricular septum].

Objective: To summarize the interim outcome and right heart development of pulmonary atresia with intact ventricular septum (PA-IVS) in children after fetal cardiac intervention (FCI). Methods: The clinical data of 5 live births underwent FCI from October 2018 to April 2019 in Women and Children's Hospital, Qingdao University were analyzed retrospectively. The development of right ventricle (RV) and tricuspid valve (TV) in uterus after FCI, at birth, the age of 6 months, 1 year and 2 years, and the final outcome were assessed. Results: Five PA-IVS fetuses were included in this study. The first evaluation was performed at 24-26 weeks of gestational age, and the FCI was performed at 26-28 weeks of gestational age. During the follow-up of 6 weeks after FCI, the minimum diameter of tricuspid annulus increased from 0.85 cm to 0.92 cm, and the minimum Z-score of tricuspid annulus decreased from -0.03 to -1.62. The minimum values of TV/mitral valve annular diameter and RV/left ventricular length ratios of all fetuses increased from 0.57, 0.52 to 0.88, 0.82, respectively. The maximum tricuspid regurgitation velocity decreased from 4.60 m/s to 3.64 m/s. No severe hemodynamic change was found in any of the fetuses. All 5 fetuses were born alive. Three cases underwent percutaneous balloon pulmonary valvuloplasty (PBPV) and stent implantation for ductus arteriosus. Two cases received PBPV alone. At follow-up (26 to 32 months), obvious development of TV was observed 6 months to 1 year after birth in 5 cases with the growth rate ranging from 19.64% to 40.00%. Meanwhile, the RV development was relatively slow at 6 months with the growth rate ranging from 9.41% to 21.42%. There were individual differences in RV development at 2 years. The growth and development of all children were equal to healthy children of the same age with the body mass index less than 18.4 kg/m2. At the last follow-up, all children had a transcutaneous oxygen saturation of greater than 0.95, three became biventricular circulation and two had circulation approximation to biventricular circulation with almost closed stent. Conclusions: The findings support the potential of development of right ventricular and tricuspid valve for fetuses with PA-IVS underwent FCI. All fetuses underwent FCI received intervention after birth, and biventricular circulation can be realized finally. The development of right ventricular and tricuspid valve is not proportional. In utero, the right ventricle develops rapidly, and the development of tricuspid valve is more advantageous after birth.

[Application of arterial duct stent in ductus-dependent hypoplastic right heart syndrome].

Objective: To summarize the experience of arterial duct (AD) stenting in children with ductus-dependent hypoplastic right heart syndrome (HRHS). Methods: Seven children including 4 cases of pulmonary atresia with intact ventricular septum (PA-IVS) with HRHS and 3 cases of critical pulmonary stenosis (CPS)-IVS with HRHS underwent AD stenting in Qingdao Women and Children's Hospital between January 2012 and January 2019. During the same period, 9 patients of PA-IVS with HRHS received Blalock Taussig (B-T) shunt. Two groups of children on the operation time, hospital stay time, intensive care time and mortality were compared.T test or Mann-Whitney U test was used for comparison between the two groups. Results: There was no significant difference in the age (18 (7-100) vs. 17 (1-142) d, U=31.000, P>0.05) and weight ((3.8±1.1) vs. (3.7±1.3) kg, t=0.272, P>0.05) between the AD stenting group and the B-T group.The operation time ((108±7) vs. (160±49) min, t=-4.304), intensive care time ((3.4±1.0) vs. (6.3±4.5) d, t=-8.692) and total hospitalization time ((10.3±1.0) vs. (26.3±1.0) d, t=-7.822) in the AD stenting group were differed significantly compared with the B-T group (all P<0.05). The transcutaneous oxygen saturation improved significantly (0.723±0.125 vs. 0.926±0.005, t=-6.044, P<0.05) after AD stenting. The diameter of AD stent ranged from 3.5 to 4.0 mm, and the length of AD stent was 16-21 mm. There were no complications such as vascular injury, acute thrombus, catheter spasm and death in the AD stenting group. The mortality of children in the B-T group was 3 in 9 cases. Three cases in the AD stenting group received pulmonary valvulotomy and bilateral Glenn operation at 6, 9 and 9 months after AD stenting, respectively. Conclusions: AD stenting is a feasible, effective, safe and minimally invasive procedure for children with ductus-dependent HRHS. It can even be used as an alternative to B-T shunt.

Correction: Role of integrin-linked kinase in regulating the protein stability of the MUC1-C oncoprotein in pancreatic cancer cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

YC-1 inhibits HIF-1 expression in prostate cancer cells: contribution of Akt/NF-kappaB signaling to HIF-1alpha accumulation during hypoxia.

Hypoxia-inducible factor 1 (HIF-1), a transcription factor that is critical for tumor adaptation to microenvironmental stimuli, represents an attractive chemotherapeutic target. YC-1 is a novel antitumor agent that inhibits HIF-1 through previously unexplained mechanisms. In the present study, YC-1 was found to prevent HIF-1alpha and HIF-1beta accumulation in response to hypoxia or mitogen treatment in PC-3 prostate cancer cells. Neither HIF-1alpha protein half-life nor mRNA level was affected by YC-1. However, YC-1 was found to suppress the PI3K/Akt/mTOR/4E-BP pathway, which serves to regulate HIF-1alpha expression at the translational step. We demonstrated that YC-1 also inhibited hypoxia-induced activation of nuclear factor (NF)-kappaB, a downstream target of Akt. Two modulators of the Akt/NF-kappaB pathway, caffeic acid phenethyl ester and evodiamine, were observed to decrease HIF-1alpha expression. Additionally, overexpression of NF-kappaB partly reversed the ability of wortmannin to inhibit HIF-1alpha-dependent transcriptional activity, suggesting that NF-kappaB contributes to Akt-mediated HIF-1alpha accumulation during hypoxia. Overall, we identify a potential molecular mechanism whereby YC-1 serves to reduce HIF-1 expression.

YC-1 induces apoptosis of human renal carcinoma A498 cells in vitro and in vivo through activation of the JNK pathway.

BACKGROUND AND PURPOSE: The aim of this study was to elucidate the mechanism of YC-1{3-(5'-hydroxy methyl-2'-furyl)-1-benzylindazole}-induced human renal carcinoma cells apoptosis and to evaluate the potency of YC-1 in models of tumour growth in mice. EXPERIMENTAL APPROACH: YC-1-mediated apoptosis was assessed by analysis of MTT, SRB, DAPI staining and flow cytometry analysis. Knockdown of JNK protein was achieved by transient transfection using siRNA. The mechanisms of action of YC-1 on different signalling pathways involved were studied using western blot. Fas clustering was analysed by confocal microscopy and in vivo efficacy was examined in a A498 xenograft model. KEY RESULTS: YC-1 displayed cytotoxicity in renal carcinoma cells at 10(-7)-10(-8) M. Increased condensation of chromatin was observed and an increase in the cell population in subG1 phase. Moreover, YC-1 triggered mitochondria-mediated and caspase-dependent pathways. YC-1 significantly induced Fas ligand expression, but did not modify either the protein levels of death receptors or ligands. In addition, Fas clustering in cells responsive to YC-1 was observed, suggesting involvement of a Fas-mediated pathway. Furthermore, YC-1 markedly induced phosphorylation of JNK and a JNK inhibitor, SP600125, and siRNA JNK1/2 significantly reversed YC-1-induced cytotoxicity and protein expression. We suggest that YC-1 induced JNK phosphorylation, the upregulation of FasL and Fas receptor clustering to promote the activation of caspases 8 and 3, resulting in apoptosis. Finally, we demonstrated the antitumour effect of YC-1 in vivo. CONCLUSIONS AND IMPLICATIONS: These data suggest that YC-1 is a good candidate for development as an anticancer drug.

Ba3B10O17Br2: a new barium borate halide with B-O layered structure.

A new barium borate halide, Ba3B10O17Br2, has been obtained. A detailed structural comparison with other barium borate halides suggested that Ba3B10O17Br2 is the first barium borate halide with a B-O layered structure. First-principles theoretical studies were conducted to aid understanding of the electronic structure and optical properties.

Role of integrin-linked kinase in regulating the protein stability of the MUC1-C oncoprotein in pancreatic cancer cells.

MUC1-C overexpression has been associated with the progression of pancreatic tumors by promoting the aggressive and metastatic phenotypes. As MUC1 is a STAT3 target gene, STAT3 plays a major role in regulating MUC1-C expression. In this study, we report an alternative mechanism by which integrin-linked kinase (ILK) post-transcriptionally modulates the expression of MUC1-C by maintaining its protein stability in pancreatic cancer cells. We found that ILK acts in concert with STAT3 to facilitate IL-6-mediated upregulation of MUC1-C; ILK depletion was equally effective as STAT3 depletion in abolishing IL-6-induced MUC1-C overexpression without disturbing the phosphorylation or cellular distribution of STAT3. Conversely, ectopic expression of constitutively active ILK increased MUC1-C expression, though this increase was not noted with kinase-dead ILK. This finding suggests the requirement of the kinase activity of ILK in regulating MUC1-C stability, which was confirmed by using the ILK kinase inhibitor T315. Furthermore, our data suggest the involvement of protein kinase C (PKC)δ in mediating the suppressive effect of ILK inhibition on MUC1-C repression. For example, co-immunoprecipitation analysis indicated that ILK depletion-mediated MUC1-C phosphorylation was accompanied by increased phosphorylation of PKCδ at the activation loop Thr-507 and increased binding of PKCδ to MUC1-C. Conversely, ILK overexpression resulted in decreased PKCδ phosphorylation. From a mechanistic perspective, the present finding, together with our recent report that ILK controls the expression of oncogenic KRAS through a regulatory loop, underscores the pivotal role of ILK in promoting pancreatic cancer progression.

Uncoupling of ATP-induced inositol phosphate formation and Ca(2+) mobilization by phorbol ester in canine cultured tracheal epithelial cells.

The regulation of the increase in inositol phosphates (IPs) production and intracellular Ca(2+) concentration ([Ca(2+)](i)) by protein kinase C (PKC) was investigated in canine cultured tracheal epithelial cells (TECs). Pretreatment of TECs with phorbol 12-myristate 13-acetate (PMA, 1 microM) for 30 min attenuated the ATP- and UTP-induced IPs formation and Ca(2+) mobilization. The concentrations of PMA that gave half-maximal (EC(50)) inhibition of ATP- and UTP-induced IPs accumulation and an increase in [Ca(2+)](i) were 5-10 and 4-12 nM, respectively. Prior treatment of TECs with staurosporine (1 microM), a PKC inhibitor, partially inhibited the ability of PMA to attenuate ATP- and UTP-induced responses, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Furthermore, analysis of cell extracts by Western blotting with antibodies against different PKC isozymes revealed that TECs expressed PKC-alpha, -betaI, -betaII, -gamma, -delta, -epsilon, -theta, and -zeta. With PMA treatment of the cells for various times, translocation of PKC-alpha, -betaI, -betaII, -gamma, -delta, -epsilon, and -theta from the cytosol to the membrane was seen after 5- and 30-min and 2- and 4-h treatment. However, 6-h treatment caused a partial down-regulation of these PKC isozymes. PKC-zeta was not significantly translocated and down-regulated at any of the times tested. In conclusion, these results suggest that activation of PKC may inhibit the phosphoinositide (PI) hydrolysis and consequently attenuate the [Ca(2+)](i) increase or inhibit independently both responses to ATP and UTP. The translocation of PKC-alpha, -betaI, -betaII, -delta, -epsilon, -gamma, and -theta induced by PMA caused an attenuation of ATP- and UTP-induced IPs accumulation and Ca(2+) mobilization in TECs.

Effect of forskolin on bradykinin-induced calcium mobilization in cultured canine tracheal smooth muscle cells.

The effects of increases in intracellular adenosine 3':5'-cyclic monophosphate (cyclic AMP) on bradykinin (BK)-induced generation of inositol phosphates (IPs) and Ca2+ mobilization were investigated in canine cultured tracheal smooth muscle cells (TSMCs). Pretreatment of TSMCs with either forskolin or dibutyryl cyclic AMP attenuated BK-stimulated responses. The inhibitory effects of these agents produced both a depression of the maximal response and a shift to the right of the concentration-response curves of BK. The water-soluble forskolin analogue L-858051, 7-deacetyl-7 beta-(r-N-methylpiperazino)-butyryl forskolin, significantly attenuated BK-stimulated IPs accumulation, while 1,9-dideoxy forskolin, an inactive forskolin, had little effect on IPs response. Moreover, SQ-22536, 9-(tetrahydro-2-furanyl)-9-H-purin-6-amine, an inhibitor of adenylate cyclase, and both H-89, N-(2-aminoethyl)-5-isoquinolinesulfonamide, and HA-1004, N-(2-guanidinoethyl)-5-isoquinolinesulfonamide, inhibitors of cyclic AMP-dependent protein kinase (PKA), reversed the ability of forskolin to attenuate BK-stimulated IPs accumulation. The KD and Bmax, values of the BK receptor for [3H]BK binding were not significantly changed by forskolin treatment for 30 min and 4 h. The AlF4(-)-induced IPs accumulation was attenuated by forskolin, indicating that G protein(s) are directly activated by AlF4- and uncoupled to phospholipase C by forskolin treatment. These results suggest that activation of cyclic AMP/PKA might inhibit the BK-stimulated PI breakdown and consequently reduce the [Ca2+]i increases or inhibit independently both responses, which is distal to the BK receptor in canine cultured TSMCs.

Activation of mitogen-activated protein kinase by oxidized low-density lipoprotein in canine cultured vascular smooth muscle cells.

Oxidized low-density lipoprotein (OX-LDL) contributes significantly to the development of atherosclerosis. However, the mechanisms of OX-LDL-induced vascular smooth muscle cell (VSMC) proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with a specific pattern of mitogen-activated protein kinase (MAPK) by [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in canine cultured VSMCs. OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in a time- and concentration-dependent manner in VSMCs. Pretreatment of these cells with pertussis toxin (PTX) for 24 hours attenuated the OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation, indicating that these responses were mediated through a receptor coupled to a PTX-sensitive G protein. In cells pretreated with PMA for 24 h and with either the PKC inhibitor staurosporine or the tyrosine kinase inhibitor genistein for 1h, substantially reduced the [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in response to OX-LDL. Removal of Ca(2+) by addition of BAPTA/AM plus EGTA significantly inhibited OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation, indicating the requirement of Ca(2+) for these responses. OX-LDL-induced [3H]thymidine incorporation and p42/p44 MAPK phosphorylation was completely inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK). Furthermore, we also showed that overexpression of dominant negative mutants of Ras (RasN17) and Raf (Raf-301) completely suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. Taken together, these results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G-protein-coupled receptor that involves the activation o Ras/Raf/MEK/MAPK pathway similar to those of PDGF-BB in canine cultured VSMCs.

Inhibition of bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilisation by phorbol ester in rat cultured vascular smooth muscle cells.

Regulation of the increase in inositol phosphate (IP) production and intracellular Ca2+ concentration ([Ca2+]i by protein kinase C (PKC) was investigated in cultured rat vascular smooth muscle cells (VSMCs). Pretreatment of VSMCs with phorbol 12-myristate 14-acetate (PMA, 1 microM) for 30 min almost abolished the BK-induced IP formation and Ca2+ mobilisation. This inhibition was reduced after incubating the cells with PMA for 4 h, and within 24 h the BK-induced responses were greater than those of control cells. The concentrations of PMA giving a half-maximal (pEC50) and maximal inhibition of BK induced an increase in [Ca2+]i, were 7.8 +/- 0.3 M and 1 microM, n = 8, respectively. Prior treatment of VSMCs with staurosporine (1 microM), a PKC inhibitor, inhibited the ability of PMA to attenuate BK-induced responses, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Paralleling the effect of PMA on the BK-induced IP formation and Ca2+ mobilisation, the translocation and downregulation of PKC isozymes were determined by Western blotting with antibodies against different PKC isozymes. The results revealed that treatment of the cells with PMA for various times, translocation of PKC-alpha, betaI, betaII, delta, epsilon, and zeta isozymes from the cytosol to the membrane were seen after 5 min, 30 min, 2 h, and 4 h of treatment. However, 24-h treatment caused a partial downregulation of these PKC isozymes in both fractions. Treatment of VSMCs with 1 microM PMA for either 1 or 24 h did not significantly change the K(D) and Bmax of the BK receptor for binding (control: K(D) = 1.7 +/- 0.2 nM; Bmax = 47.3 +/- 4.4 fmol/mg protein), indicating that BK receptors are not a site for the inhibitory effect of PMA on BK-induced responses. In conclusion, these results demonstrate that translocation of PKC-alpha, betaI, betaII, delta, epsilon, and zeta induced by PMA caused an attenuation of BK-induced IPs accumulation and Ca2+ mobilisation in VSMCs.

Pharmacological and functional characterization of bradykinin receptors in rat cultured vascular smooth muscle cells.

The pharmacological properties of bradykinin receptors were characterized in rat cultured vascular smooth muscle cells (VSMCs) using [3H]-bradykinin as a ligand. Analysis of binding isotherms gave an apparent equilibrium dissociation constant (K(D)) of 1.2 +/- 0.2 nM and a maximum receptor density (Bmax) of 47.3 +/- 4.4 fmol/mg protein. The specific binding of [3H]-bradykinin to VSMCs was inhibited by the B2 receptor-selective agonists (bradykinin and kallidin) and antagonists ([D-Arg0, Hyp3, Thi5, D-Tic7, Oic8]-bradykinin (Hoe 140) and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) with an order of potency as kallidin = bradykinin = Hoe 140 > [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin, but not by a B1 receptor-selective agonist (des-Arg9-bradykinin) and antagonist ([Leu8, des-Arg9]-bradykinin). Stimulation of VSMCs by bradykinin produced a concentration-dependent inositol phosphate (IP) accumulation, and initial transient peak of [Ca2+]i with half-maximal responses (pEC50) were 7.53 and 7.69, respectively. B2 receptor-selective antagonists (Hoe 140 and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) significantly antagonized the bradykinin-induced responses with pK(B) values of 8.3-8.7 and 7.2-7.9, respectively. Pretreatment of VSMCs with pertussis toxin (100 ng/ml, 24 h) did not alter the bradykinin-induced inositol phosphate accumulation and [Ca2+]i changes in VSMCs. Removal of external Ca2+ led to a significant attenuation of responses induced by bradykinin. Influx of external Ca2+ was required for the bradykinin-induced responses, since Ca2+-channel blockers, nifedipine, verapamil, and Ni2+, partially inhibited the bradykinin-induced IP accumulation and Ca2+ mobilization. These results demonstrate that bradykinin stimulates phosphoinositide hydrolysis and Ca2+ mobilization via a pertussis toxin-insensitive G-protein in rat VSMCs. Bradykinin B2 receptors may be predominantly mediating IP accumulation and subsequently induction of Ca2+ mobilization may function as the transducing mechanism for bradykinin-stimulated contraction of vascular smooth muscle.