Morphometrics predicts the differential regurgitant fraction in bilateral pulmonary arteries of patients with repaired tetralogy of fallot

In patients with repaired tetralogy of Fallot (rTOF), the regurgitant fraction (RF) in left pulmonary artery (LPA) and right pulmonary artery (RPA) is usually unequal. The morphometrics may play a crucial role in this RF discrepancy. Cardiovascular MR of 79 rTOF patients and 20 healthy controls were retrospectively enrolled. Forty-four from the 79 patients were matched in age, sex and body surface area to the 20 controls and were investigated for: (1) phase-contrast flow of main pulmonary artery (MPA), LPA, and RPA; (2) vascular angles: the angles between the thoracic anterior-posterior line (TAPL) with MPA (θM-AP), MPA with RPA (θM-R), and MPA with LPA (θM-L); (3) cardiac angle, the angle between TAPL and the interventricular septum; (4) area ratio of bilateral lung and hemithorax regions. Compared with the 20 controls, the 44 rTOF patients exhibited wider θM-AP, sharper θM-L angle, and a smaller θM-L/θM-R ratio. In the 79 rTOF patients, LPA showed lower forward, backward, and net flow, and greater RF as compared with RPA. Multivariate analysis showed that the RF of LPA was negatively associated with the θM-L/θM-R ratio and the age at surgery (R2 = 0.255). Conversely, the RF of RPA was negatively associated with the left lung/left hemithorax area ratio and cross-sectional area (CSA) of LPA, and positively associated with CSA of RPA and MPA (R2 = 0.366). In rTOF patients, the RF of LPA is more severe than that of RPA, which may be related to the vascular morphometrics. Different morphometric parameters are independently associated with the RF of LPA or RPA, which may offer potential insights for surgical strategies.

[Outcomes at discharge of preterm infants born <34 weeks' gestation]

Objective: To investigate the incidence and trend of short-term outcomes among preterm infants born <34 weeks' gestation. Methods: A secondary analysis of data from the standardized database established by a multicenter cluster-randomized controlled study "reduction of infection in neonatal intensive care units (NICU) using the evidence-based practice for improving quality (REIN-EPIQ) study". This study was conducted in 25 tertiary NICU. A total of 27 192 infants with gestational age <34 weeks at birth and admitted to NICU within the first 7 days of life from May 2015 to April 2018 were enrolled. Infants with severe congenital malformation were excluded. Descriptive analyses were used to describe the mortality and major morbidities of preterm infants by gestational age groups and different admission year groups. Cochran-Armitage test and Jonckheere-Terpstra test were used to analyze the trend of incidences of mortality and morbidities in 3 study-years. Multiple Logistic regression model was constructed to analyze the differences of outcomes in 3 study-years adjusting for confounders. Results: A total of 27 192 preterm infants were enrolled with gestational age of (31.3±2.0) weeks at birth and weight of (1 617±415) g at birth. Overall, 9.5% (2 594/27 192) of infants were discharged against medical advice, and the overall mortality rate was 10.7% (2 907/27 192). Mortality for infants who received complete care was 4.7% (1 147/24 598), and mortality or any major morbidity was 26.2% (6 452/24 598). The incidences of moderate to severe bronchopulmonary dysplasia, sepsis, severe intraventricular hemorrhage or periventricular leukomalacia, proven necrotizing enterocolitis, and severe retinopathy of prematurity were 16.0% (4 342/27 192), 11.9% (3 225/27 192), 6.8% (1 641/24 206), 3.6% (939/25 762) and 1.5% (214/13 868), respectively. There was a decreasing of the overall mortality (P<0.001) during the 3 years. Also, the incidences for sepsis and severe retinopathy of prematurity both decreased (both P<0.001). However, there were no significant differences in the major morbidity in preterm infants who received complete care during the 3-year study period (P=0.230). After adjusting for confounders, infants admitted during the third study year showed significantly lower risk of overall mortality (adjust OR=0.62, 95%CI 0.55-0.69, P<0.001), mortality or major morbidity, moderate to severe bronchopulmonary dysplasia, sepsis and severe retinopathy of prematurity, compared to those admitted in the first study year (all P<0.05). Conclusions: From 2015 to 2018, the mortality and major morbidities among preterm infants in Chinese NICU decreased, but there is still space for further efforts. Further targeted quality improvement is needed to improve the overall outcome of preterm infants.

Performance of the EuroSCORE II Model in Predicting Short-Term Mortality of General Cardiac Surgery: A Single-Center Study in Taiwan

BACKGROUND

The latest European System for Cardiac Operative Risk Evaluation (EuroSCORE) II is a well-accepted risk evaluation system for mortality in cardiac surgery in Europe.

OBJECTIVES

To determine the performance of this new model in Taiwanese patients.

METHODS

Between January 2012 and December 2014, 657 patients underwent cardiac surgery at our institution. The EuroSCORE II scores of all patients were determined preoperatively. The short-term surgical outcomes of 30-day and in-hospital mortality were evaluated to assess the performance of the EuroSCORE II.

RESULTS

Of the 657 patients [192 women (29.22%); age 63.5 ± 12.68 years], the 30-day mortality rate was 5.48%, and the in-hospital mortality rate was 9.28%. The discrimination power of this new model was good in all populations, regardless of 30-day mortality or in-hospital mortality. Good accuracy was also noted in different procedures related to coronary artery bypass grafting, and good calibration was noted for cardiac procedures (p value > 0.05). When predicting surgical death within 30 days, the EuroSCORE II overestimated the risk (observed to expected: 0.79), but in-hospital mortality was underestimated (observed to expected: 1.33). The predictive ability [area under the curve (AUC) of the receiver operating characteristic (ROC) curve] and calibration of the EuroSCORE II for 30-day mortality (0.792) and in-hospital mortality (0.825) suggested that in-hospital mortality is a better endpoint for the EuroSCORE II.

CONCLUSIONS

The new EuroSCORE II model performed well in predicting short-term outcomes among patients undergoing general cardiac surgeries. For short-term outcomes, in-hospital mortality was better than 30-day mortality as an indicator of surgical results, suggesting that it may be a better endpoint for the EuroSCORE II.

[Analysis of clinical phenotype and genotype of Chinese children with disorders of sex development]

Objective: To explore the heterogeneity and correlation of clinical phenotypes and genotypes in children with disorders of sex development (DSD). Methods: A retrospective study of 1 235 patients with clinically proposed DSD in 36 pediatric medical institutions across the country from January 2017 to May 2021. After capturing 277 DSD-related candidate genes, second-generation sequencing was performed to analyzed the heterogeneity and correlation combined with clinical phenotypes. Results: Among 1 235 children with clinically proposed DSD, 980 were males and 255 were females of social gender at the time of initial diagnosis with the age ranged from 1 day of age to 17.92 years. A total of 443 children with pathogenic variants were detected through molecular genetic studies, with a positive detection rate of 35.9%. The most common clinical phenotypes were micropenis (455 cases), hypospadias (321 cases), and cryptorchidism (172 cases) and common mutations detected were in SRD5A2 gene (80 cases), AR gene (53 cases) and CYP21A2 gene (44 cases). Among them, the SRD5A2 mutation is the most common in children with simple micropenis and simple hypospadias, while the AMH mutation is the most common in children with simple cryptorchidism. Conclusions: The SRD5A2 mutation is the most common genetic variant in Chinese children with DSD, and micropenis, cryptorchidism, and hypospadias are the most common clinical phenotypes. Molecular diagnosis can provide clues about the biological basis of DSD, and can also guide clinicians to perform specific clinical examinations. Target sequence capture probes and next-generation sequencing technology can provide effective and economical genetic diagnosis for children with DSD.

Glut5 Knockdown in the Nucleus Tractus Solitarii Alleviates Fructose-Induced Hypertension in Rats

BACKGROUND

Several studies have suggested mechanisms whereby excessive fructose intake increases blood pressure (BP). Glucose transporter 5 (GLUT5) is a fructose transporter expressed on enterocytes, and its involvement in the nucleus tractus solitarius (NTS)-modulated increase in BP following fructose intake remains unclear.

OBJECTIVES

Herein, we investigated whether NTS Glut5 knockdown (KD) can alleviate fructose-induced hypertension in rat models.

METHODS

Male Wistar-Kyoto rats (6-8 weeks old; average weight: 230 g) were randomly assigned into 4 groups [control (Con), fructose (Fru), fructose + scrambled (Fru + S), and Fru +  KD]. The Con group rats had ad libitum access to regular water, and the other 3 groups were provided 10% fructose water ad libitum for 4 weeks (2 weeks before lentiviral transfection in the Fru + S and Fru + KD groups). Glut5 short hairpin RNA was delivered into the NTS of rats using a lentivirus system. Fructose-induced hypertension was assessed via the tail-cuff technique, a noninvasive blood pressure measurement approach. GLUT5-associated and other insulin signaling pathways in the NTS of rats were assessed using immunofluorescence and immunoblotting analyses. We evaluated between-group differences using the Mann-Whitney U test or Kruskal-Wallis 1-way ANOVA.

RESULTS

Compared with the Fru + S group, the Fru + KD group had reduced sympathetic nerve hyperactivity (48.8 ± 3.2 bursts/min; P < 0.05), improved central insulin signaling, upregulated protein kinase B (AKT; 3.0-fold) and neuronal NO synthase (nNOS; 2.78-fold) expression, and lowered BP (17 ± 1 mmHg, P < 0.05). Moreover, Glut5 KD restored signaling dependent on adenosine 5'-monophosphate-activated protein kinase and reduced fructose-induced oxidative stress 2.0-fold, and thus decreased NAD(P)H oxidase in p67-phox 1.9-fold within the NTS.

CONCLUSIONS

Fructose-induced reactive oxygen species generates in the NTS of rats through GLUT5 and receptor for advanced glycation end products signaling, thus impairing the AKT-nNOS-NO signaling pathway and ultimately causing hypertension.

[A rare anatomical variation of ileocolic veins involving in gastrocolic vein trunk: case report and literature review]

Objective: Due to its various anatomical variations and numerous branches, the gastrocolic vein trunk (Henle trunk) is the most common site to develop bleeding and other complications in laparoscopic right hemicolectomy for colon cancer. This study aims to investigate the role of ileocolic vein (ICV) joining with Henle trunk, a rare anatomical variation. Methods: A rare case whose ICV was newly found to involve in the formation of Henle trunk during laparoscopic resection of right hemicolon cancer was reported as right gastroepiploic vein+ right colic vein+superior right colic vein+ICV. This anatomical variation was confirmed by multi-slice spiral CT coronal two-dimensional reconstruction of right hemicolon angiography. The literatures about ICV participating in formation of Henle trunk were systematically searched from PubMed, The Cochran Library, CNKI net and Wanfang database, and the occurrence probability and composition of its anatomical variation were analyzed. Results: This was a 47-year-old female patient who underwent laparoscopic right hemicolectomy. When the vessels were dissected during operation, it was found that ICV did not accompany the ileocolic artery, but directly flowed into Henle trunk. Two-dimensional reconstructed CT images of right hemicolon vessels showed that the composition of Henle trunk was rarely varied, which was composed of right gastroepiploic vein, right colonic vein, superior right colonic vein and ICV. Five literatures were enrolled from literature retrieval. A total of 12 cases with ICV participating in the construction of Henle trunk were reported, with a probability of 0.27%-6.31% and 6 forms of the formation of Henle trunk. In this case, Henle trunk was made up of right gastroepiploic vein, right colonic vein, upper right colonic vein and ICV, which was reported for the first time. Conclusions: ICV involving in Henle trunk is a rare vascular variation, and this type of variation should be fully recognized. Careful dissection during operation is necessary to prevent intraoperative bleeding caused by improper operation.

[Comparative analysis of serum glutamate and gamma-aminobutyric acid levels in patients with bipolar depressive disorder and major depression disorder]

Objective: To investigate the difference of serum glutamate (Glu) and gamma- aminobutyric acid (GABA) levels between depressive patients and bipolar disorder patients with depressive episodes. Methods: From May 2018 to March 2019, forty-seven patients with depression (depression group) and 45 patients with bipolar depressive episode (bipolar depression group) were selected from the department of psychiatry, the First Affiliated Hospital of Jinan University, and 41 healthy controls (healthy control group) were simultaneously recruited from the community. The subjects' depression and anxiety were assessed by 17 items of Hamilton depression scale (HAMD-17) and Hamilton Anxiety Scale (HAMA). The serum levels of Glu, GABA and Glu decarboxylase (GAD) were detected by enzyme-linked immunosorbent assay (ELISA) . Results: The serum Glu level ( (36±7) mg/L, (37±7) mg/L vs (28±4) mg/L, F=10.97, P<0.01) and Glu/GABA ratio (5.77±0.35, 8.18±0.24 vs 3.35±0.33, F=37.68, P<0.01) in depression and bipolar depression groups were higher than those of healthy control group, while the GABA level ((6.1±0.7) μmol/L,(4.1±0.8) μmol/L vs (8.1±1.2) μmol/L, F=21.61, P<0.01) and GAD ((31±6) U/L, (31±6) U/L vs (35±6) U/L, F=5.61, P<0.01) were lower than those of healthy control group. The level of serum GABA in bipolar depression group was lower than that in depression group. However, Glu/GABA was higher in bipolar depression group than that in depression group (P<0.01). The level of serum GABA in depression group was negatively correlated with HAMD sleep disorder factor (r=-0.46, P=0.01). Conclusions: Both depression and bipolar depression have abnormal levels of Glu, GABA neurotransmitters and imbalance between Glu and GABA in peripheral blood circulation. Moreover, these abnormalities are more obvious in patients with bipolar depression.

Gabapentin Reduces Blood Pressure and Heart Rate through the Nucleus Tractus Solitarii

Background

Oral and intravenous gabapentin can markedly attenuate blood pressure (BP) in hypertensive rats. The nucleus tractus solitarii (NTS) is the primary integrative center for cardiovascular control and other autonomic functions in the central nervous system. However, the signaling mechanisms involved in gabapentin-mediated cardiovascular effects in the NTS remain unclear. We investigated whether the nitric oxide synthase (NOS) signaling pathway was involved in gabapentin-mediated BP regulation in the NTS of spontaneously hypertensive (SHR) rats.

Methods

SHR rats were anesthetized with urethane at age 10-12 weeks. Arterial pressure and heart rate (HR) were monitored through a femoral artery catheter. For stereotaxic intra-NTS microinjection, the dorsal surface of the medulla was exposed by limited craniotomy. We observed that unilateral microinjection of gabapentin into the NTS whether to change dose-related BP and HR. Then, unilateral microinjection of gabapentin into the NTS before and after N(ω)-nitro-L-arginine methyl ester (L-NAME) treatment whether to change blood pressure and heart rate.

Results

Unilateral microinjection of gabapentin into the NTS produced prominent dose-related depressor and bradycardic effects in SHR rats. The cardiovascular effects of gabapentin were attenuated by the prior administration of the NOS inhibitor, L-NAME.

Conclusions

Gabapentin modulated central BP and HR control in the NTS of SHR rats in this study through NOS signaling.

Involvement of Endothelial Nitric Oxide Synthase Activation in Midkine-Mediated Central Hypotensive Effects

The growth factor midkine (MK) has been implicated in various biologic and pathologic events. It has been shown that the peripheral influence of MK on cardiovascular regulation is due to an influence on the renin-angiotensin system (RAS). The nucleus tractus solitarii (NTS) is the primary integrative center for cardiovascular control and other autonomic functions in the central nervous system. However, the signaling mechanisms involved in MK-mediated cardiovascular effects in the NTS remain unclear. In this study, we investigated whether the RAS and/or N-methyl-D-aspartate (NMDA) receptor-calmodulin-endothelial nitric oxide synthase (eNOS) signaling pathways were both involved in MK-mediated blood pressure (BP) regulation in the NTS of Wistar-Kyoto (WKY) rats. Intra-NTS microinjection and immunoblot analysis were used to evaluate the signal pathway. WKY rats were anesthetized with urethane. Unilateral microinjection of MK (600 fmol) into the NTS produced a dose-dependent decrease in BP and heart rate (HR). The depressor effects were observed before and after microinjection of the angiotensin-converting enzyme (ACE) inhibitor lisinopril (2.4 fmol), or the angiotensin receptor blockers (ARB) inhibitor valsartan (7.5 pmol). However, lisinopril and valsartan did not diminish the MK-mediated cardiovascular effects in the NTS. Microinjection of the NMDA receptor antagonist MK801 (1 nmol) or the NOS inhibitor N-nitro l-arginine methyl ester (L-NAME), (33 nmol), into the NTS attenuated the MK-induced hypotensive effects. Pretreatment with an eNOS inhibitor N5-iminoethyl-l-ornithine (L-NIO) (6 nmol) attenuated the MK-induced hypotensive effects. In this study, the data showed that MK might play a role in central cardiovascular regulation in the NTS. These results suggest that MK decreased BP and HR in the NTS probably acting via the NMDA receptor-calmodulin-eNOS signaling pathway.

Successful repair of neonatal tricuspid regurgitation due to chordae rupture

Neonatal rupture of the chordae of tricuspid valve with severe regurgitation is rare and disastrous. We report on a full-term female neonate presented with cyanosis caused by severe tricuspid regurgitation (TR) due to anterior leaflet chordal rupture. After initial stabilization by prostaglandin E1 infusion, successful early repair was achieved with artificial chordae implantation. The unique pathophysiology and the therapeutic strategy of this situation will be described.

Cutaneous protothecosis on the bilateral wrists of a food handler

Cutaneous protothecosis is caused by the achlorophyllic algae Prototheca, typically presenting as a localized plaque in immunocompetent individuals. We report a patient with bilateral erythematous plaques and pustules on her forearms, which had initially been treated with steroids for presumed eczema. Histology showed spherical spore-like bodies with internal morula-like septation, which were positive for periodic-acid-Schiff (PAS) staining, consistent with cutaneous protothecosis. Definitive treatment with oral itraconazole resulted in resolution of the lesions.

Fontan Operation in a Patient with Severe Hypoplastic Right Pulmonary Artery, Single Ventricle, and Heterotaxy Syndrome

Assessment of the pulmonary circulation status including pressure, resistance, size, and absence of anatomical distortion, is crucial to the successful Fontan operation. Most patients are found to have acceptable pulmonary arteries after previous palliation, although some degree of distortion is not uncommon. However, in rare instances, some patients have only one functioning lung with another pulmonary artery seriously hypoplastic or atretic. For theses patients, completion of a Fontan operation will be challenging. We reported a 17-year-old girl with a single ventricle and heterotaxy syndrome and only her left lung functioning, who underwent one-lung Fontan operation with a satisfactory result.

Papular angiolymphoid hyperplasia and lymphoplasmacytic plaque: a clinical and histological spectrum

Acral pseudolymphomatous angiokeratoma of children (APACHE) is a rare form of cutaneous pseudolymphoma characterized byangiomatous papules with a predilection for the acral regions of children. Classically, a dense dermal lymphocytic infiltrate composed of both T and B cells is seen in histological specimens, together with prominent vessels lined by plump endothelial cells. Increasing evidence suggests that this condition is neither necessarily acral, pseudolymphomatous, nor angiokeratomatous. It may not always be a pediatric disease. Therefore, the correctness of its nomenclature has been questioned. Herein, we report threecases whose clinical and histological features were consistent with the diagnosis of APACHE. To our knowledge, this is the first report of APACHE from Southeast Asia. We also discuss why we believe "APACHE" to be a misnomer and support "papular angiolymphoid hyperplasia" as a more accurate and encompassing term. In addition, we illustrate a case with significant overlapping features with lymphoplasmacytic plaque in children, suggesting that both entities may exist on a clinical andhistological spectrum.

Quality of life in people with mental illness in non-residential community mental health services in Hong Kong

OBJECTIVE

To identify the subjective quality of life in people with chronic mental health problems who were in non-residential community mental health services, and to investigate factors affecting their quality of life after the illness.

METHODS

People with mental illness (n = 105) were recruited. They were assessed with the self-rated Hong Kong Chinese version of the World Health Organization Quality of Life Brief questionnaire.

RESULTS

The participants had lower total quality-of-life and the 4 domain scores of the questionnaire than the general population. They were particularly dissatisfied with their financial situation. Duration of illness was positively correlated with subjective quality-of-life variables while age at onset of the mental illness was negatively correlated with subjective quality of life, in particular the physical health, psychological health, and environmental domains.

CONCLUSION

This study highlighted the significance of duration and age at onset of illness in subjective quality of life of people with mental illness. A longitudinal study to test the causal relationships between these factors and the quality of life in people with mental illness is recommended.

Obstacles and solutions to screening psoriasis patients for cardiovascular risk factors

BACKGROUND

Psoriasis has been linked with cardiovascular risk factors (CVRFs), including the metabolic syndrome, yet many patients with psoriasis remain unscreened.

OBJECTIVE

To assess the reasons for lack of screening for CVRFs in psoriasis patients, and the impact of an education programme targeting these deficiencies.

METHODS

All patients with psoriasis, regardless of severity, and all dermatologists working at the National Skin Centre (NSC) in Singapore were surveyed over a 2-month period on their attitudes and knowledge regarding psoriasis and cardiovascular risk. This was followed by a targeted programme which was implemented over 2 months to address these identified deficiencies. Patients and doctors were surveyed a second time to assess the effects of the intervention.

RESULTS

Obstacles to screening included lack of patient knowledge, patients not considering screening important, and lack of time during the clinic consultation. After the intervention, there was a significant increase in the proportion of patients who were aware of increased cardiovascular risk in psoriasis (33.0% to 62%), with more patients attending screening (39.1% to 63.2%). While the level of doctors' knowledge did not significantly increase, there was an increase in the proportion of patients who were screened post-intervention (37.1% to 66.2%), and more doctors reported that they were more likely to screen psoriatic patients from an earlier age (30.2% to 58.1%).

CONCLUSIONS

The obstacles in implementing universal screening for CVRFs in psoriasis patients stem from patient, doctor and system factors. A comprehensive programme targeting all aspects of this ecosystem helps to achieve holistic care for patients with psoriasis.

The hedgehog signaling pathway, a new therapeutic target for treatment of ischemic heart disease

The hedgehog (Hh) protein is involved in angiogenesis and cardiovascular development via activation of the classical ligand-dependent signaling transduction. So its potential therapeutic meaning of Hh signaling proteins to the ischemic heart diseases has been greatly explored. Recent studies show that up-regulated expression of hypoxia-induced factor-1 (HIF-1) and inflamemation in ischemic tissues activate the Hh signaling cascade in a GLI-dependent or independent way, resulting in elevated expression levels of pro-angiogenic and agiogenic factors to facilitate angiogenesis. In addition, Hh signaling pathway activation can promote residual myocardial progenitors, endogenous EPCs and MSCs differentiating into cardiomyocytes, inhibit cardiomyocyte apoptosis; thirdly, high level of exogenous Hh signaling can reduce myocardial ischemic/reperfusion injuries(I/R). In conclusion, three kinds of mechanisms induced by Hh signaling pathway participate in the heart repair after myocardial ischemia. Therefore, Hh agonists including Hh protein, Hh gene transfer and small molecule agonist could be part of a potential therapeutic strategy for acute or chronic ischemic heart disease.

Hemopericardium from right atrial laceration in a newborn

We report the case of a newborn who suffered right atrial laceration during delivery. To our knowledge, there has been no previous report of blunt injury causing right atrial laceration with hemopericardium complicated by cardiac tamponade in the perinatal period.

Performance of European system for cardiac operative risk evaluation in Veterans General Hospital Kaohsiung cardiac surgery

BACKGROUND

The European System for Cardiac Operative Risk Evaluation (EuroSCORE) model is a widely-used risk prediction algorithm for in-hospital or 30-day mortality in adult cardiac surgery patients. Recent studies indicated that EuroSCORE tends to overpredict mortality. The aim of our study is to evaluate the validity of EuroSCORE in Veterans General Hospital Kaohsiung (VGHKS) cardiac surgery including a number of different surgical and risk subgroups.

METHODS

From January 2006 to December 2009, 1,240 adult patients who underwent cardiac surgery in VGHKS were included in this study. The study was followed the guidelines of the Ethics Committee of Kaohsiung Veterans General Hospital, Taiwan. Both additive and logistic score of all patients were calculated depending on the formula in the official EuroSCORE website. The entire cohort, different surgical type and risk stratification subgroups were analyzed. Model discrimination was tested by determining the area under receiver operating characteristic (ROC) curve. Model calibration was tested by the Hosmer-Lemeshow chi-square test. Clinical performance of model was assessed by comparing the observed and predicted mortality rates.

RESULTS

There were significant differences between the VGHKS and European cardiac surgical populations. The additive score and logistic score for the overall group were 7.16% and 12.88%, respectively. Observed mortality was 10.72% overall, 5.68% for isolated coronary artery bypass grafting (CABG), 4.67% for the mitral valve only and 4.25% for the aortic valve only group. The discriminative ability EuroSCORE was very good in all and various surgical subgroups, with area under the ROC curve from 0.75 to 0.87. The addictive and logistic models of EuroSCORE showed excellent accuracy, 0.839 and 0.845, respectively. Good calibration power was recognized by p value higher than 0.05 for the entire cohort and all subgroups of patients except for isolated CABG. The logistic EuroSCORE model overestimated mortality to different degrees in the various subgroups, indicating that the logistic EuroSCORE needs to be recalibrated by a factor about 0.55 for uncomplicated surgery and low-risk groups, and 0.85 for high-risk patients with original additive score more than six.

CONCLUSION

EuroSCORE is simple and easy to use. In the present study, the model demonstrated excellent accuracy in all and various surgical subgroups in VGHKS cardiovascular surgery populations. Good calibration ability in all and different risk categories was identified except for isolated CABG group. Recalibration factors of 0.55 and 0.85 were suggested for the various operative subgroups and risk categories.

Role of multi-slice and three-dimensional computed tomography in delineating extracardiac vascular abnormalities in neonates

BACKGROUND

Recent advances in multi-slice computed tomography (MSCT) and three-dimensional computed tomography (3D CT) provide good-resolution images and short scan time for complete diagnosis of congenital heart disease (CHD). In the present study, we found that MSCT rapidly provides clinically relevant information for diagnosing extracardiac vascular anatomy in neonates with CHD. It is less invasive, necessitating only minimum or no sedation and a relatively small amount of contrast material. These advantages are crucial, especially for critically ill neonates.

METHODS

Between January 2007 and December 2008, MSCT scans were conducted on 41 neonates who were admitted to our neonatal intensive care unit. All the neonates were suspected to have complex CHD after an initial echocardiography examination. The scans were focused on detecting extracardiac vascular anatomy and abnormalities. All the image data sets were sent to image processing workstations for multiplanar interactive viewing and 3D reconstruction.

RESULTS

High-resolution MSCT scan images were obtained from 41 patients. Reported indications and findings of extracardiac abnormalities and related structural anatomy pertaining to congenital heart disease from MSCT and 3D CT findings were confirmed by clinical and surgical findings by a team of multidisciplinary congenital heart disease specialists.

CONCLUSION

Based on clinical and surgical confirmation of the MSCT scan results from a multidisciplinary congenital heart disease specialist team, we concluded that adequate information on CHD, specifically that regarding extracardiac abnormalities of the anatomy, can be obtained and MSCT can be used to replace cardiac catheterization.

Ventilator-associated pneumonia after pediatric cardiac surgery in southern Taiwan

BACKGROUND AND PURPOSE

To determine the frequency, risk factors, associated pathogens, and outcomes of ventilator-associated pneumonia (VAP) after pediatric cardiac surgery.

METHODS

This was a retrospective review of the medical records of patients younger than 18 years with congenital heart disease (CHD) who underwent cardiac surgery from January 2005 to December 2007. Patients were categorized into 2 groups: with and without VAP.

RESULTS

Of 100 patients, 13% acquired VAP. Most patients (85%) who developed VAP were infants younger than 1 year. Patients with complex CHD were more likely to develop VAP than patients with simple CHD (chi(2) = 7.69; p < 0.03). Two independent and modifiable risk factors were identified: prolonged use of mechanical ventilation (adjusted odds ratio [AOR], 15.196; 95% confidence interval [CI], 2.158-107.2) and prolonged use of a central venous catheter (AOR, 7.342; 95% CI, 1.054-51.140). The cardiopulmonary bypass time and duration of chest tube drainage were not risk factors. The development of VAP increased pediatric intensive care unit duration of stay (p < 0.006), duration of hospital stay (p < 0.001), and mortality rate (p < 0.001). Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus were the most common pathogens isolated from endotracheal aspirate.

CONCLUSIONS

VAP is common after congenital heart surgery. Physicians must pay special attention to infants with complex CHD because they are at high risk for the development of VAP after congenital heart surgery. Shortening the duration of mechanical ventilation and central venous catheter placement are critical factors for reducing the risk for VAP.

Influence of Pulmonary Regurgitation Inequality on Differential Perfusion of the Lungs in Tetralogy of Fallot After Repair

OBJECTIVES

The purpose of this study was to evaluate the influence of pulmonary regurgitation inequality on differential perfusion of the lungs in tetralogy of Fallot (TOF) after repair.

BACKGROUND

Asymmetry of lung perfusion is one of the best predictors of outcome in TOF after repair. A recent phase-contrast magnetic resonance imaging (PC-MRI) study found prominent regurgitation inequality between the bilateral pulmonary arteries in TOF after repair.

METHODS

Forty-three TOF post-repair patients (median age = 51 months, 31 men) received PC-MRI and 99mTc-labeled macroaggregates of albumin perfusion scintigraphy (PS) in the same day. We took PC-MRI measurements of forward flow volume (FFV), backward flow volume (BFV), and net flow volume (NFV) (NFV = FFV - BFV) and regurgitation fraction (RF) (RF = BFV/FFV) at the left and right pulmonary arteries (LPA and RPA). The differential perfusion of the left lung (L%) (L% = left lung/left + right lung) as calculated by NFV ratio, by FFV ratio of PC-MRI, and by PS were compared.

RESULTS

The discrepancy between L% by NFV versus L% by PS was affected by the severity of RF of LPA (r = -0.51, p = 0.001); agreement between L% by NFV versus L% by PS was good (intraclass correlation coefficient [Ri] = 0.87) if RF of LPA <0.4 (n = 23) but downgraded (Ri = 0.51) and underestimated the L% (median of error = -14%, range = -25.3% to 5.5%) if RF of LPA > or =0.4 (n = 20). In contrast, agreement between L% by FFV versus L% by PS was high and unaffected by RF of LPA (Ri = 0.94, 0.92, respectively).

CONCLUSIONS

While integrating PC-MRI of pulmonary artery as a comprehensive MRI evaluation of TOF after repair, conventional NFV ratio method tended to underestimate the left lung perfusion and may lead to unnecessary intervention. The FFV ratio method should be used for precise assessment of differential lung perfusion.

Clinics in diagnostic imaging (116). Ruptured hepatocellular carcinoma

A 37-year-old Chinese man with chronic hepatitis B, who frequently defaulted past follow-up appointments, was admitted for acute abdomen and shock. Computed tomography of the abdomen revealed a ruptured hepatocellular carcinoma involving the left lobe. After fluid resuscitation, gelfoam embolisation was performed to arrest the bleeding, followed by segmental resection of the hepatic lesion. There was aggressive recurrence following left segmental hepatectomy, and despite two courses of transarterial chemoembolisation, the patient died of local and pulmonary recurrences five months after his initial presentation. The management of hepatocellular carcinoma rupture is discussed.

Temporal correlation-based dynamic contrast-enhanced MR imaging improves assessment of complex pulmonary circulation in congenital heart disease

A temporal correlation (TC) mapping method is proposed to help bolus chasing during dynamic contrast-enhanced (DCE) MRI of complex pulmonary circulation (CPC) in patients with congenital heart disease. DCE-MRI was performed on five healthy male subjects (23-24 years old) and 25 patients (nine males and 16 females, 0.25-44 years old), and TC maps were generated by performing pixel-based computation of cross-correlations to the pulmonary artery with a series of time shifts in all subjects. Qualitative and quantitative evaluations were performed in comparison with original DCE images. TC maps exhibited a better signal-to-noise ratio (SNR) by factors of 4.3 and 1.3 in the lung parenchyma, pulmonary veins, and superior artery/vein; a better intraparenchymal contrast-to-noise ratio (CNR) by factors of 1.5-5.4; and a significantly higher conspicuity in all regions except the pulmonary arteries when graded with a five-point score. TC maps evaluated by two experienced clinicians significantly added relevant information (P<0.001), and in some cases affected the final diagnosis. We conclude that TC maps facilitate bolus chasing for DCE-MRI by reducing recirculation effects and interframe fluctuations, and hence complements morphological imaging of CPC in patients with complex congenital heart disease.

[Down-regulation of ETA receptor of vascular smooth muscle cells by 17 beta-estradiol]

In the present study, the effects of 17 beta-estradiol on vascular reactivity of ovariectomized rats and proliferation of cultured rat aortic smooth muscle cells were studied. The vascular reactivity was significantly increased in ovariectomized rats compared with the sham-operated animals. The selective ETA receptor antagonist BQ123 inhibited the increase in [3H]-TdR incorporation in response to ET-1 on vascular smooth muscle cells (VSMCs). 17 beta-estradiol also attenuated the ET-1 effects in a dose-dependent manner. The results of RT-PCR and Western blot show that expression of ETA receptor was decreased after treatment with 17 beta-estradiol. The effect of 17 beta-estradiol was partially inhibited by estrogen receptor antagonist tamoxifen. The above results demonstrate that proliferation of VSMCs stimulated by ET-1 was mainly mediated through ETA receptor. Due to the down-regulation of ETA receptor and mediation of estrogen receptor, 17 beta-estradiol inhibits the ET-1-induced proliferation of VSMCs and decreases the vascular reactivity of ovariectomized rats.

[Effect of microinjection of L-arginine into the caudal pressor area of medulla oblongata on cardiovascular responses in rats]

AIM

To study the effect of microinjection L-arginine, a precursor for the synthesis of nitric oxide into the functionally identified caudal pressor area (CPA) in ventral surface of medulla oblongata.

METHODS

Artery pressure (AP), renal perfusion pressure (RPP) and heart rate were recorded to study the effects of microinjection of NO related drugs into CPA.

RESULTS

(1) Unilateral microinjection of L-arginine (60 - 100 nmol) into CPA produced prominent dose-related depressor and bradycardic effects and reduced renal perfusion pressure. (2) Unilateral microinjection of L-arginine (100 nmol) 3 min after microinjection of methylene blue (10 nmol) into CPA did not significantly change AP and RPP. (3) Unilateral microinjection of L-glutamate (350 nmol) into CPA elicited pressor effect which was significantly dose-related attenuated by prior microinjection of L-arginine (60-100 nmol) into the same area.

CONCLUSION

Theses results suggest that L-arginine-NO pathway in the CPA participates in the central regulation of arterial pressure and may have a key role in the inhibiting of glutamatergic neurotransmission in the anesthetized rats.

[Effects of microinjection of L-arginine into the depressor area of ventral surface of medulla oblongata on cardiovascular responses]

AIM

To study the effects of L-arginine, a precursor for the synthesis of nitric oxide, when it was microinjected into the functionally identified depressor area in ventral surface of medulla oblongata (VSMd) on cardiovascular responses.

METHODS

Artery pressure (AP), perfusion pressure of the kidney (PPK) and heart rate were recorded to study the effects of microinjection of NO related drugs into VSMd.

RESULTS

(1) Unilateral microinjection of L-arginine (60 - 100 nmol) into VSMd produced prominent dose-related pressor effect and increased PPK but without significant changes in heart rate. (2) Microinjection of L-Arg (100 nmol) 3 min after microinjection of methylene blue (10 nmol) into VSMd did not significantly change AP and PPK. (3) Unilateral microinjection L-glutamate (350 nmol) into VSMd elicited depressor effect (-34.97% +/- 4.33%). The depressor effect was significantly dosed related attenuated by prior microinjection L-arginine (60 - 100 nmol) into the same area.

CONCLUSION

These results suggest that the L-arginine - NO pathway in the VSMd participate in the central regulation of artery pressure and the pathway may have a key role in inhibiting glutamatergic neurotransmission in the anesthetized rats.

Which depressed patients respond to nefazodone and when?

BACKGROUND

Retrospective data analyses were conducted of a single-blind trial of 993 outpatients with nonpsychotic major depression (DSM-III-R) treated for 12 weeks with nefazodone to provide a more specific picture of the nature and timing of response or remission to acute-phase treatment.

METHOD

All patients participated in a single-blind, 16-week lead-in to obtain responders eligible for a subsequent double-blind, randomized continuation phase trial. Outcomes were defined by the 17-item Hamilton Rating Scale for Depression (HAM-D). A > or = 50% reduction from baseline defined response, and a total HAM-D exit score of < or =8 defined remission.

RESULTS

Of all patients who entered the trial, 41.8% (last observation carried forward) responded at or before week 4 (early responders), and an additional 25.2% responded thereafter; 18.3% achieved remission at or before week 4; 33.6% achieved remission after week 4. Thus, 77.3% of those responding ultimately remitted. On average, remission followed response by 2 weeks. The average end-of-treatment dose was 376 mg/day at exit (last observation carried forward). Responders or remitters (as opposed to nonresponders or nonremitters) had lower baseline depressive symptomatology and were more likely to be married or cohabiting.

CONCLUSION

The full symptomatic benefit of antidepressant medication may not be apparent until completion of an 8- to 10-week trial. A high number of responders ultimately attained remission. Baseline demographic and clinical features were not highly predictive of who would or would not benefit from nefazodone. For routine care, a minimal acute-phase trial, using a 50% reduction in baseline symptom severity to define response, should be 8 weeks. Whether ultimate nonresponders can be identified earlier than 8 weeks deserves further study.

[Effect of aldosterone on the secretion of endothelin by ventricular fibroblasts]

Using cell culture, radioimmunoassay for endothelin and RT-PCR, the effect of aldosterone on the endothelin secretion of ventricular fibroblasts was studied. The results showed that aldosterone (1 x 10(-7) mol/L) promoted the expression of ppET-1 mRNA, which began to increase in 2 hours and attained the highest level in 4 hours, thereafter decreased; aldosterone increased the endothelin level in ventricular fibroblasts and fibroblast conditioned growth medium (FCGM) as well, which was blocked by spironolactone (1 x 10(-6) mol/L), an aldosterone receptor antagonist. The results suggest that aldosterone can increase endothelin secretion by ventricular fibroblasts, which can be inhibited by its receptor antagonist spironolactone.

[Role of mitogen-activated protein kinase in the inhibition of myocardial hypertrophy by nitric oxide in renovascular hypertensive rats]

The aim of this study was to examine the effects of L-arginine, a nitric oxide (NO) precursor, on protein expression of endothelial nitric oxide (eNOS), nitrite/nitrate content, protein expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) and the activity of mitogen-activated protein kinase (MAPK) in cardiac tissues in renovascular hypertensive rats (RHR). The Goldblatt renovascular hypertensive model was established by two-kidney one clip method. The rats were divided into four groups, respectively treated with 50, 150 and 450 mg/kg L-arginine and 150 mg/kg L-arginine plus 10 mg/kg L-NAME (an eNOS inhibitor) (i.p.). Another group did not receive specific treatment from the 5th week after renal artery constriction. Control group was sham-operated. Mean arterial blood pressure (MABP) and the ratio of left ventricular weight to body weight (LVW/BW) were measured 8 weeks after treatment. eNOS protein expression, nitrite/nitrate content, MKP-1 protein expression and MAPK activity in cardiac tissues were detected using Western blot analysis, enzyme-reduction method and substrate in-gel kinase assay, respectively. It was found that L-arginine significantly inhibited the increase of MABP and LVW/BW, attenuated the activity of MAPK, increased protein expression of eNOS and MKP-1 and potentiated production of NO in cardiac tissue with the most effective dosage of 150 mg/kg, and these effects of L-arginine could be inhibited by L-NAME. These results suggest that MKP-1 may play an important role in the NO-induced inhibition of myocardial hypertrophy. The anti-hypertrophic effects of L-arginine may involve increase of eNOS protein expression and NO production, potentiation of MKP-1 protein expression, and inhibition of MAPK activity in the cardiac tissue of RHR.

[Role of conditioned growth medium for ventricular fibroblasts in promoting fibroblast collagen synthesis and proliferation]

Ventricular fibroblasts were cultured using conditioned growth medium for ventricular fibroblasts (FCGM). The rate of the total collagen synthesis of ventricular fibroblasts was measured by assaying the incorporation rate of [3H]-proline, whereas the proliferation of ventricular fibroblasts was assessed by determining the incorporation rate of [3H]-TdR and the expression of c-fos genes. FCGM significantly increased the [3H]-proline incorporation rate and [3H]-TdR incorporation rate of fibroblasts in a dose-dependent manner. Furthermore, FCGM promoted the c-fos gene expression of fibroblasts, which attained its maximum in 1 h. BQ123, an ETA receptor antagonist, partially blocked the above effects of FCGM, but AT1 receptor antagonist CV11974 and alpha-adrenergic receptor antagonist regitin did not. It is suggested that the ventricular fibroblast has an autorine function in promotion of collagen synthesis and proliferation of fibroblasts by secreting endothelin and other bioactive substances.

[The effect of aldosterone of promotion on proliferation of ventricular fibroblasts]

AIM

To study the effect of promoting aldosterone on proliferation of ventricular fibroblasts.

METHODS

Assay of [3H]-TdR incorporation rate and RT-PCR were used.

RESULTS

Aldosterone could promote [3H]-TdR incorporation of ventricular fibroblasts, the effective dose of aldosterone was among (1 x 10(-9)-1 x 10(-6))mol/L, and had dose-dependent manner, the c-fos gene was expressed after stimulated by aldosterone for 15 min, and studied the highest in 1 h, then reduced later. Spironolactone, aldosterone receptor antagonist could block the effect of aldosterone.

CONCLUSION

Aldosterone promotes the proliferation of ventricular fibroblasts, mediated by aldosterone receptor.

Nitric oxide inhibits the expression of proto-oncogene c-fos induced by angiotensin II and endothelin-1 in cardiomyocytes

The effect of nitric oxide (NO) on the hypertrophic response and the proto-oncogene c-fos expression induced by angiotensin II (AII) or endothelin-1 (ET-1) was investigated in the primary culture of neonatal rat cardiomyocytes. Total protein content of cardiomyocytes (used as the index of cardiac myocyte hypertrophy) was determined by the Bradford method. The proto-oncogene c-fos expression was assessed using reverse transcription-polymerase chain reaction (RT-PCR) standardized with glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RT-PCR was performed in a single tube using gene-specific primers and the SuperScript One-Step RT-PCR System. Total protein content of cardiomyocytes increased significantly on day 5 after A II treatment or on day 3 after ET-1 treatment and the increased protein content was inhibited by SNP (NO donor). A II, ET-1 and PMA (protein kinase C activator) induced the c-fos gene expression of cardiomyocytes, while L-arginine inhibited it. The L-arginine effect was blocked by L-NAME (NOS inhibitor). SNP inhibited the c-fos gene expression of cardiomyocytes induced by A II,ET-1 or PMA as well. These results suggest that NO can inhibit the hypertrophic response and the proto-oncogene c-fos expression of cardiomyocytes induced by A II or ET-1 and the cross-link may be located at the site of protein kinase C.

[17beta -estradiol induced nitric oxide release in vascular endothelial cells]

Bovine aortic endothelial cells (BAECs) were used to study the effect of 17beta -estradiol (E(2)) on nitric oxide (NO) release, nitric oxide synthase (eNOS) mRNA expression and intracellular free calcium con~cen~tration ([Ca(2+)](I)) and modulation of the effect of E(2) by estrogen receptor (ER) antagonist tamoxifen and NOS inhibitor L-NAME. E(2) (10(-12) 10(-8) mol/L) induced NO release of BAECs in a concentration-dependent manner and the abundant expression of eNOS mRNA in BAECs increased obviously after treatment with E(2) (10(-8)mol/L) for 48 h. These effects were evidently inhibited by tamoxifen (10(-7)mol/L) and L-NAME (10(-6) mol/L). Furthermore treatment with E(2) (10(-8) mol/L) for 48 h significantly increased the resting [Ca(2+)](I) and the rise of [Ca(2+)](I) induced by ATP in BAECs. These results suggest that E(2)-induced NO release and eNOS mRNA expression in BAECs may be mediated by ER and related to calcium mobilization.

[MKP-1 regulates the cardiomyocyte hypertrophic responses induced by angiotensin II]

The aim of this study was to determine the regulation by MKP-1 of MAPK activity and protein expression in cardiomyocyte hypertrophic response induced by Ang II. Neonatal rat cardiomyocyte hypertrophic response was assayed by cell surface area, protein synthesis rate and protein content. MAPK activity was determined by an in-gel kinase assay. Protein expression of MAPK and MKP-1 were detected by Western blotting. The results are as follows. (1) Ang II induced promotion of (3)H-leucine incorporation and increase in cell protein content and cell surface area in a dose-dependent manner. Pretreatment with a selective AT(1) receptor antagonist CV11974 or a specific MEK inhibitor PD098059, cardiomyocyte hypertrophic response induced by Ang II was inhibited by 85% and 32.5%, respectively. (2) After pretreatment with PD098059 or CV11974, AngII-induced increases in p44MAPK and p42MAPK protein expression and enzyme activity (expressed by gamma-(32)P-ATP incorporation) were all inhibited obviously. (3) With treatment of myocytes by Ang II for 5 min, MAPK activity determined by p44MAPK and p42MAPK protein expression began to increase, while MKP-1 protein expression was detected within 30 min and lasted more than 2 h following treatment with Ang II. (4) Pretreatment of cardiomyocytes with actinomycin D (3 microgram/ml) for 30 min inhibited MKP-1 protein expression, while p44MAPK and p42MAPK protein expression was still detected 120 min after Ang II treatment. The above results demonstrate that activation of MAPK plays an important role in Ang II-induced cardiomyocyte hypertrophic response in neonatal rat cardiomyocytes through MKP-1 mediated inactivation of p44MAPK and p42MAPK.cardiomyocyte hypertrophic response in neonatal rat cardiomyocytes through MKP-1 mediated inactivation of p44MAPK and p42MAPK.

[Effect of protein kinase C on inhibition of nitric oxide synthesis in cultured neonatal rat cardiomyocytes by angiotensin II]

The purpose of the present study was to investigate the effect of angiotensin II (Ang II) on nitric oxide (NO) concentration and its signal transduction pathway in cultured neonatal rat cardioymocytes. NO content was measured in cultured neonatal rat cardiomyoctes using a nitrite/nitrate colormetric method kit. NO content was represented by measured nitrite (NO(2)) and nitrate (NO(3)) level (NO(2)/NO(3)). The results are as follows. NO production was decreased by Ang II in a dose dependent manner but increased by L Arg. The Saralasin, an antagonist of Ang II receptor, inhibited the effect of Ang II on NO production. The effect of Ang II on NO production was inhibited by NOS blocker N(G)-nitro-L-arginine methyl ester L-NAME but not by L-Arg. Pretreatment of Phorbol 12-myristate 13-acetate PMA , a PKC activator, decreased NO concentration significantly. This effect was strengthened by L-NAME. Staurosporine, a PKC inhibitor, abolished the inhibiting effect of Ang II on production of NO. The above results suggest that Ang II could decrease NO content in cultured neonatal rat cardiomyocytes significantly. Activity of NOS may be inhibited by Ang II. Ang II receptor was involved in the inhibitory effect of Ang II on NO production. Activation of protein kinase C (PKC) decreased significantly NO production in cultured neonatal rat cardiomyoctes, which appears to be associated with PKC in the signal transduction pathway.

[Nitric oxide changes aortic function in rats with renal hypertension]

This work was undertaken to investigate the effect of nitric oxide (NO) on aortic function of two-kidney and one-clip (2K1C) rats with renal hypertension. Animals were divided into 5 groups: the sham operation, 2K1C, captopril, L-arginine and L-NAME groups. The results are as follows. At the 4th week after constriction of the left renal artery, the mean arterial pressure was significantly elevated. In isolated aortic rings, acetylcholine-induced dilation was attenuated, and phenylephrine induced contractile response was markedly enhanced. The level of aorta cGMP content was significantly lowered. These changes were abolished in 2K1C rats treated with captopril. L-arginine partially reversed the aortic vascular reactivity of 2K1C rats, and elevated aortic cGMP content. In 2K1C rats treated with nitric oxide synthase inhibitor, L-NAME, blood pressure was increased further, acetylcholine-induced aorta diastolic response was attenuated further and cGMP content reduced, while phenylephrine-induced contractile response was unaffected. These results suggest that deficiency of nitric oxide production and increase in renin-angiotensin system activity may contribute to vascular endothelial dysfunction of 2K1C rats, and these factors may be involved in development and maintenance of 2K1C renal hypertension.

[Cardiocyte hypertrophy induced by cultured neonatal rat ventricular fibroblast conditioned growth medium]

The present work demonstrated that cultured neonatal rat ventricular fibroblast conditioned growth medium (FCGM) could significantly increase cell surface area and protein content and promote (3)H -Leucine incorporation on neonatal rat cardiomyocyte. The above effect was strongest on the third day, and was dose-dependent. BQ(123), an ET-A receptor antagonist, significantly blocked the effect, while CV11974, an Ang II I-type receptor antagonist, and regitin, an alpha-adrenergic receptor antagonist, did not. These results suggest that there are some substances promoting hypertrophy of cardiomyocytes in FCGM, which may be ET-1. The FCGM-induced increases in cardiomyocyte protein synthesis and cell surface area were inhibited partially by pertusis toxin (PTX) and PKC inhibitor staurosporine (ST), suggesting that the hypertrophic effect is related with PTX sensitive G protein and PKC.

[The role of nitric oxide in the angiotensin II-induced hypertrophy of cardiac myocytes]

The purpose of this study was to determine the role of nitric oxide (NO) in the angiotensin II-induced hypertrophic response in cultured neonatal rat cardiac myocytes. Angiotensin II induced significant increase of protein content, decrease of NOS activity in cultured neonatal rat cardiomyocytes and decrease of NO concentration in the culture medium. Angiotensin II decreased significantly the eNOS mRNA level of cardiomyocytes. Saralasin and PTX inhibited significantly the increased protein content, the decreased NOS activity and the decreaseed NO production of cardiomyocytes induced by angiotensin II. Sodium nitroprusside increased significantly NO concentration in the culture medium and inhibited significantly the increased protein content of cardiomyocytes induced by angiotensin II. The results suggest that angiotensin II may induce hypertrophy of cultured neonatal rat cardiomyocytes. The effect of angiotensin II is mediated by receptors which are coupled with PTX-sensitive G protein and may be related to the decreased eNOS gene expression, NOS activity and NO production. Exogenous NO can prevent the hypertrophy of cardiomyocytes induced by angiotensin II.

[Effect of angiotensin II on c-fos expression and protein synthesis in cultured rat myocardial cells]

The present study was to investigate the effects of angiotensin II on c-fos mRNA expression and protein synthesis in cultured neonatal rat myocardial cells. The results showed that angiotensin II induced c-fos mRNA expression, increased protein content in a dose-dependent manner and stimulated 3H-leucine incorporation rate. All these effects were blocked by angiotensin II receptor antagonist saralasin. The angiotensin II-induced expression of c-fos gene was also blocked by Ca2+ channel antagonist nicardipine.

[Effect of ET-1 on intracellular free calcium in cultured neonatal myocardial cells]

In this present study, the effects of ET-1 on intracellular free calcium concentration ([Ca2+]i) and the underlying mechanisms were investigated in cultured neonatal rat myocardial cells loaded with fura-2/AM. The results are as follows. ET-1 induced an increase of [Ca2+]i in a dose-dependent manner, which consisted of a transient and sustained phase. BQ123, a selective ETA receptor antagonist, blocked the ET-1 induced [Ca2+]i responses, suggesting that these responses were mediated by ETA receptors. After removal of extracellular Ca2+, ET-1 induced the transient increase of [Ca2+]i without the sustained change. Protein kinase C (PKC) agonist PMA attenuated the ET-1 induced transient [Ca2+]i increase. Amiloride and nifedipine did not block the [Ca2+]i change induced by ET-1. After pretreatment of myocardial cells with pertussis toxin, ET-1 also induced the transient increase of [Ca2+]i but did not affect the sustained increase. These results suggest that the transient [Ca2+]i increase may involve pertussis toxin-insensitive G protein and the sustained one may be caused by extracellular calcium influx, in which pertussis toxin sensitive G protein is involved. Furthermore, PKC, but not Na+/H+ exchange, plays an important role in these effects.

[ET-1 induces the expression of prooncogene c-fos in cultured neonatal rat myocardial cells]

In the present study, the effect of endothelin-1 (ET-1) on the expression of proto-oncogene c-fos in cultured neonatal rat myocardial cells was investigated. The results are as follows: ET-1 induced c-fos expression in a dose-dependent manner. Selective ET(A) receptor antagonist blocked ET-1-induced responses. Protein kinase C(PKC) agonist PMA induced c-fos expression.PKC inhibitor staurosporine blocked ET-1 induced c-fos expression. Calcium channel blocker, nifedipine did not significantly affect the expression of c-fos induced by ET-1. These results suggest that in cultured neonatal cardiomyocytes, ET-1 induced c-fos gene expression is mediated by ET(A) receptor with the participation of protein kinase C, while the voltage-dependent L-type Ca(2+) channel is not involved.

GEF-mediated GDP/GTP exchange by monomeric GTPases: a regulatory role for Mg2+?

GTPases share highly conserved guanine nucleotide-binding domains and fulfill diverse functions through a common molecular switch. An inactive GDP-bound protein is turned on by a guanine nucleotide exchange factor (GEF) that catalyzes exchange of GTP for GDP, but unfortunately little is known about the mechanism of GEF action. A common mechanism for GDP/GTP exchange can be envisioned wherein GEFs activate monomeric GTPases through transient disruption of Mg2+ coordination in the nucleotide-binding pocket while stabilizing a nucleotide-free (and cation-free) conformation. After guanine nucleotide exchange, Mg2+ coordination is restored to complete the conformational switch to the active GTP-bound state. Evidence in the literature highlighting an important regulatory role for Mg2+ in the mechanism of GEF-mediated GDP/GTP exchange by monomeric GTPases is summarized.