Long-term amlodipine-based combination therapy attenuates seasonal variation of blood pressure in hypertensive patients.

Objectives: This study was to investigate whether long-term amlodipine-based combination therapy attenuates seasonal variation of office blood pressure (BP) in hypertensive patients. Methods: The data of 206 patients recruited in the Nanchang site of CHIEF trial were retrospectively analyzed. All patients received an amlodipine-based therapy for three years after reaching target BP with a 12-week titration treatment. Among them, 106 patients received amlodipine plus amiloride/hydrochlorothiazide (AA group) and 100 received amlodipine plus telmisartan (AT group) therapies. These patients were followed up every three months . The difference between the highest and lowest values of outdoor temperature in each three months was calculated as the seasonal temperature difference (T-d) and seasonal BP difference was calculated in the similar way. BP control rates in each season were calculated. Results: In the three years, the highest SBP and DBP values occurred in winter and the lowest values in summer. As a result, the BP control rate in summer was the highest and that in winter was the lowest, especially for SBP. Although T-d levels were similar during three following-up years, the seasonal SBP/DBP differences in 2011 were significantly lower than 2009 (10.03 ± 5.74/6.96 ± 3.72 vs 14.36 ± 8.19/9.78 ± 5.21 mmHg, P < .05), suggesting seasonal variation in BP was obviously reduced. Meanwhile, similar change was observed in AA and AT groups. Conclusions: Besides lower BP effectively, long-term amlodipine-based combination therapy could alleviate the seasonal BP variation in high-risk hypertensive patients.

Longer rewarming time in finger cooling test in association with HbA1c level in diabetics.

OBJECTIVE: To assess if rewarming time in finger cooling test (FCT) as an indicator of microvascular dysfunction is abnormal in patients with type 2 diabetes mellitus (T2DM). METHODS: Forty-three T2DM patients and 48 healthy controls with similarly distributed baseline demographic, clinical and laboratory parameters were subjected to FCT involving 60-second index finger immersion into water at 4°C. Finger temperature was measured before FCT (baseline-T), immediately after cooling stimulus (T0), and at one-minute intervals until baseline-T recovery. Temperature decline amplitude was calculated as the difference between T0 and baseline-T, and rewarming time as time elapsed from T0 to baseline-T recovery. RESULTS: T2DM patients compared with healthy controls had statistically similar baseline-T, significantly larger temperature decline amplitude, significantly lower T0, and significantly longer rewarming time. In T2DM patients, rewarming time positively correlated with T2DM duration (r=0.513, p<0.001) and glycated hemoglobin (HbA1c) level (r=0.446, p=0.003), which also were its independent predictors in multivariate regression analysis. CONCLUSIONS: Patients with T2DM display abnormal FCT results suggestive of microvascular dysfunction, with T2DM duration and HbA1c level independently predicting rewarming time.

Modified shock index is a predictor for 7-day outcomes in patients with STEMI.

SUBJECT: The aim of this study was to compare the predictive values of modified shock index (MSI) and shock index (SI) for 7-day outcome in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: This retrospective study included 160 consecutive patients with STEMI and emergency percutaneous coronary intervention. The blood pressure (BP) and heart rate (HR) measured at emergency department were used to calculate SI (HR/systolic BP) and MSI (HR/mean artery pressure). The major adverse cardiac events (MACE) included all-cause mortality, life-threatening arrhythmias, cardiogenic shock, and Killip class within 7 days. RESULTS: Forty-nine patients had increased MSI (≥1.4), whereas 72 had increased SI (≥0.7). Except the parameters on BP and HR, other parameters were similar between the normal and increased SI groups. However, the increased MSI group had significantly higher age (69.0 ± 13.0 years vs 63.9 ± 12.9 years, P = .025) than the normal MSI group. The 7-day all-cause mortality was 8.8%, and MACE rate was 24.4% in this study. Both increased SI and increased MSI predicted higher MACE rates. However, the odds ratios of increased MSI for all-cause mortality (6.8 vs 3.4), cardiogenic shock (3.0 vs 1.6), life-threatening arrhythmias (9.1 vs 4.6), and MACE (6.8 vs 3.4) were higher than those of increased SI. Modified shock index and SI were independent factor for MACE, but the odds ratio of MSI was higher than of SI (3.05 vs 1.07). CONCLUSIONS: Both SI and MSI in emergency department could predict the all-cause mortality and MACE rates within 7 days in patients with STEMI, but MSI may be more accurate than SI.

[SCN5A mutation in patients with Brugada electrocardiographic pattern induced by fever].

OBJECTIVE: To explore the relationship between SCN5A, SCN1b, SCN3b and GPD1L genotypes and the risk of malignant arrhythmia in patients with Brugada electrocardiographic pattern induced by fever. METHODS: The clinical data and peripheral blood of patients with Brugada electrocardiographic pattern induced by fever were collected. Patients with depolarization abnormality associated with hypertension, coronary heart disease, drugs and other factors were excluded. The direct DNA sequencing was used to screen the mutation of candidate gene SCN5A, SCN1b, SCN3b and GPD1L. If gene variation was found, mutation or polymorphism was then determined by comparison with 200 control individuals. The relationship between genotype and phenotype as well as the risk of malignant arrhythmia were analyzed. RESULTS: Five eligible patients with fever-induced Brugada ECG pattern were included in this study. TypeI Brugada ECG was presented in all five patients in fibrile state and disappeared in normothermia. No sudden cardiac death (SCD) occurred and no ventricular arrhythmia was presented in Holter monitor during the 3 to 5 years follow-up period. Six gene variants were found including a novel missense mutation of base C to T, named Arg965 Cys (R965C), which located in 965 codon of the 17 exon in SCN5A, and five SCN5A polymorphisms including A29A (c.87A>G), R1193Q (c.3578G>A), D1819D (c.5457T>C), exon11 -24G>A, exon23 +4A>G. CONCLUSION: SCN5A mutation is related to fever-induced Brugada ECG pattern. However, individuals with Brugada ECG pattern induced by fever bear low risk of malignant arrhythmia and SCD during fibrile state and follow up in this small patient cohort.

The L-shaped association between superoxide dismutase levels and blood pressure in older Chinese adults: community-based, cross-sectional study.

BACKGROUND: As an antioxidant, serum superoxide dismutase (SOD) have been found to be associated with hypertension. METHODS: The data were derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), a prospective cohort study in China. We explored the association between serum SOD and blood pressure (BP) using multivariable correction analysis in an older Chinese population. RESULTS: We observed a significantly gradual downward trend in the association between serum SOD levels and diastolic BP (DBP) in participants with lower serum SOD levels (< 58 IU/mL), while no associations were observed between serum SOD levels and DBP in participants with higher serum SOD levels (> 58 IU/mL). Similar results showed a significant gradual downward trend in associations between serum SOD levels and the risk of diastolic hypertension only at SOD < 58 IU/mL. Multiple linear regression analysis suggested that serum SOD was negatively correlated with DBP (Sß = -0.088,P < 0.001) but not with SBP (Sß = 0.013, P = 0.607). Multiple logistic regression analysis suggested that serum SOD was independently associated with the risk of diastolic hypertension (OR = 0.984, 95% CI: 0.973-0.996, P = 0.010) but not with the risk of systolic hypertension (OR = 1.001, 95% CI: 0.990-1.012,P = 0.836)) after adjusting for relevant confounding factors. Serum SOD levels (< 58 IU/mL, > 58 IU/mL) were an effect modifier of the association between serum SOD and DBP (interactionP = 0.0038) or the risk of diastolic hypertension (interaction P = 0.0050). CONCLUSIONS: Our study indicated for the first time that there was an L-shaped association between serum SOD levels and the risk of diastolic hypertension in the older Chinese population.

Comparison of efficacy and safety between ultrathin bioresorbable polymer sirolimus-eluting stents and thin durable polymer drug-eluting stents: a systematic review and meta-analysis of the literature.

OBJECTIVE: Ultrathin bioresorbable polymer sirolimus-eluting stents (BP SES) have been proposed as an alternative to thin durable polymer drug-eluting stents (DP DES). Although BP SES show a significant decrease in target lesion failure rates, clear superiority with respect to efficacy and safety of BP SES in comparison to DP EES has not been consistently proven. METHODS AND RESULTS: A comprehensive search of several electronic databases identified studies that assessed efficacy and safety of BP SES, compared with DP EES. Relative risks (RRs) were pooled across studies using a fixed-effects model and a random-effect model, respectively, calculating pooled RRs and associated 95% confidence intervals (CIs). The I statistic was used to assess heterogeneity. We retrieved six studies enrolling >7000 patients. BP SES significantly reduced the risk of target vessel myocardial infarction (RR, 0.79; 95% CI, 0.64-0.97; I = 0%; Test for overall effect: z = 2.24, P = 0.03) in comparison with DP EES using a random-effects model. Use of BP SES was associated with a significant reduction in any myocardial infarction (RR, 0.83; 95% CI, 0.70-0.98; I = 12%; Test for overall effect: z = 2.19, P = 0.03), using a fixed-effects model. The subgroup analyses demonstrated, following-up ≥2 years, a statistically significant 27% RR increase in the risk of all-case death for patients randomized to BP SES (RR, 1.27; 95% CI, 1.01-1.60; I = 0%; Test for overall effect: z = 2.08, P = 0.04). No differences in cardiac death, stent thrombosis events (STE), target lesion revascularization (TLR) and target vessel revascularization (TVR) between BP SES and DP EES were observed. CONCLUSION: BP SES significantly reduced the risk of any myocardial infarction and target vessel myocardial infarction in comparison with DP EES. There were no differences in cardiac death, STE, TLR, TVR and all-cause death with its follow-up time <2 year between BP SES and DP EES. Following-up ≥2 years, a statistically significant 27% RR increase in the risk of all-case death for patients randomized to BP SES was observed.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study.

BACKGROUND: The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran. METHODS: A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed. RESULTS: During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51). CONCLUSION: This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran. CLINICAL TRIAL REGISTRATION: NCT02414035, https://clinicaltrials.gov.

[NADPH oxidase activity does not affect cellular cholesterol loading in vascular smooth muscle cells].

Reactive oxygen species generated by NADPH oxidase enhance aortic vascular smooth muscle cell proliferation and migration which play an important role in the pathophysiology of atherosclerosis. We investigated the role of NADPH oxidase in the cellular cholesterol metabolism in vascular smooth muscle cells using p47phox-deficient cells. Wild-type and p47phox knockout vascular smooth muscle cells were loaded with cholesterol for 72 h by using 10 mg/L cholesterol:methyl-beta-cyclodextrin complexes and then incubated with or without 0.3 mg/L thrombin for 10 min. Foam cell formation was determined by accumulation of intracellular cholesterol, oil Red O-stained lipid droplets. After cholesterol loading, cellular lipid droplets raised sharply, cellular cholesterol increased from (31.4+/-2.0) to (61.0+/-2.1) mg/g protein (P<0.05) in wild-type cells, and from (29.8+/-2.5) to (51.3+/-3.1) mg/g protein (P<0.05) in p47phox deficient cells, but the difference between the two cell types was not significant. Immunostaining showed decreased levels of smooth muscle alpha-actin and increased levels of macrophage marker Mac-2 in both wild-type and p47phox deficient vascular smooth muscle cells. One of the macrophage-related inflammation genes, monocyte chemoattractant protein-1 (MCP-1) expression did not change in both two cell types detected by immunostaining. Although additional incubating with thrombin, another macrophage-related inflammation gene, vascular cell adhesion molecule-1 (VCAM-1) expression was similar in all groups analyzed by real-time RT-PCR. However, the expression of ATP-binding cassette transporter A1 (ABCA1), acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1), the key proteins in cellular cholesterol metabolism, were similarly increased (P<0.05) in both two cell types as determined by quantitative real-time RT-PCR and Western blot, and it was not related to the state of oxidative stress. Interestingly, the expression of adipophilin, the lipid droplet related protein, had the similar results with ABCA1 and ACAT1, but, in wild-type cells, its expression also increased merely incubating with thrombin as determined by quantitative real-time RT-PCR. Together, these results suggest that p47phox-dependent NADPH oxidase is not involved in transdifferentitation of vascular smooth muscle cells into macrophage-like state after cholesterol loading. Deleting p47phox gene does not affect the cellular cholesterol metabolism in vascular smooth muscle cells.

White coat effect in hypertensive patients: the role of hospital environment or physician presence.

This study was to evaluate the role of hospital environment or physician presence for white coat effect (WCE) in hypertensive patients. At first, 54 hypertensive outpatients diagnosed on office blood pressure (OBP) were included for 2-week placebo run in. During the second week of the run in period, home BP was measured using electronic BP monitors for 5-7 days. Finally, 26 sustained hypertensive patients with home systolic BP/diastolic BP over 135/85 (but <180/110) mm Hg were enrolled for 8-week treatment of nifedipine controlled-release tablet. In the visit day, BP was measured by patient-self (OBP-p) or by doctor (OBP-d) according to order determined with randomization method. The self-BP measurement was performed in a reception room of hospital. The differences between home BP and OBP-d or OBP-p were calculated as WCE calculated on doctor-measurement (WCE-d) or WCE calculated on patient-measurement (WCE-p), respectively. The home and OBP were measured with the same BP device for each patient during the study period. In the total 54 outpatients received placebo, the WCE-d was similar to the WCE-p (for systolic BP 6.6 ± 14.4 vs. 6.8 ± 15.8 mm Hg, NS; for diastolic BP 3.3 ± 8.8 vs. 2.9 ± 9.2 mm Hg, NS). Meanwhile, the 26 sustained hypertensive patients had similar systolic WCE-d and WCE-p (4.8 ± 10.3 vs. 5.0 ± 12.2 mm Hg, NS) at placebo stage. Similarly, these values were comparable (3.0 ± 14.0 vs. 2.2 ± 14.4 mm Hg, NS) in treatment stage. Hospital environment plays a main role for the WCE in hypertensive patients.

[Effect of puerarin on ADMA-DDAH system in human umbilical vein endothelial cells cultured with oxidized free radical].

OBJECTIVE: To observe the effects of puerarin on activity of dimethylarginine dimethylaminohydrolase (DDAH) in human umbilical vein endothelial cells (HUVECs) cultured with oxidized free radical (OFR), to explore the effect of puerarin on metabolic mechanism of asymmetric dimethylarginine (ADMA). METHODS: HUVECs of the 3rd - 6th passage cultured with modified Jaffe's method were divided into 4 groups, the blank control group cultured with DMEM medium, the OFR group cultured with DMEM medium containing 0.1 mmol of OFR per liter, the puerarin group 1 and 2 cultured with DMEM medium containing 0.1 mmol of OFR per liter as well as 0.5 mg/ml and 1.0 mg/ml of puerarin respectively. After being incubated for 24 h, activity of nitric oxide synthase (NOS), contents of nitric oxide (NO), ADMA, endothelin (ET), and L-citrulline (L-cit) in the supernate were measured, and DDAH protein expression in the lysate was detected by Western blotting. RESULTS: Compared with those in the blank control group, ADMA and ET contents were higher, while the levels of NO and L-cit and the activity of NOS were lower markedly, but the DDAH expression changed insignificantly in the OFR group. These abnormalities were restored significantly in the puerarin groups. CONCLUSION: The increase of ADMA in OFR injured HUVECs was correlated with the reduction of DDAH activity and irrelevant to DDAH expression. Puerarin could promote ADMA metabolism through increasing DDAH activity, and improve NOS activity, thus to reduce the impairing of OFR on endothelial function.

How to evaluate BP measurements using the oscillometric method in atrial fibrillation: the value of pulse rate variation.

An oscillometric device is recommended for blood pressure (BP) measurement in atrial fibrillation (AF), but there is still controversy concerning its accuracy. Therefore, evaluation of BP values in AF patients remains a challenge. This study included 251 patients with AF and 154 participants with sinus rhythm (SR). Pulse rate (PR) and BP were measured using an oscillometric device three times. The differences between the highest and lowest PR and the systolic and diastolic BP (SBP and DBP) were calculated as ΔPR, ΔSBP and ΔDBP, respectively. AF patients were stratified with respect to ΔPR in 0-5, 6-10, 11-15 and >15 subgroups. The AF group had a greater ΔPR (12.1±8.6 vs. 4.10±3.21 b.p.m., P<0.001), ΔSBP and ΔDBP than the SR group at similar SBP and DBP. A positive correlation existed between ΔPR and ΔSBP (r=0.255, P<0.001) in AF patients, but no correlation was found in SR subjects. Meanwhile, the ΔSBP in the 0-5 and 6-10 subgroups (9.58±5.61 and 10.67±6.77 vs. 8.45±5.25 mm Hg, nonsignificant) was similar to the SR group, whereas ΔSBP in the 11-15 and >15 subgroups was significantly greater than the SR group. Regardless of ΔPR, the ΔDBP in the AF group was significantly greater than that of the SR group. The AF patients who exhibited greater variability in their PR also had a greater variability in their SBP readings. The SBP measurement for AF patients is accurate as the measurement for patients with SR if the ΔPR is of 0-10 b.p.m. in AF.

Is 10-second electrocardiogram recording enough for accurately estimating heart rate in atrial fibrillation.

BACKGROUND: At present, the estimation of rest heart rate (HR) in atrial fibrillation (AF) is obtained by apical auscultation for 1min or on the surface electrocardiogram (ECG) by multiplying the number of RR intervals on the 10second recording by six. But the reasonability of 10second ECG recording is controversial. METHODS: ECG was continuously recorded at rest for 60s to calculate the real rest HR (HR60s). Meanwhile, the first 10s and 30s ECG recordings were used for calculating HR10s (sixfold) and HR30s (twofold). The differences of HR10s or HR30s with the HR60s were compared. The patients were divided into three sub-groups on the HR60s <80, 80-100 and >100bpm. RESULTS: No significant difference among the mean HR10s, HR30s and HR60s was found. A positive correlation existed between HR10s and HR60s or HR30s and HR60s. Bland-Altman plot showed that the 95% reference limits were high as -11.0 to 16.0bpm for HR10s, but for HR30s these values were only -4.5 to 5.2bpm. Among the three subgroups with HR60s <80, 80-100 and >100bpm, the 95% reference limits with HR60s were -8.9 to 10.6, -10.5 to 14.0 and -11.3 to 21.7bpm for HR10s, but these values were -3.9 to 4.3, -4.1 to 4.6 and -5.3 to 6.7bpm for HR30s. CONCLUSION: As 10s ECG recording could not provide clinically accepted estimation HR, ECG should be recorded at least for 30s in the patients with AF. It is better to record ECG for 60s when the HR is rapid.

How to estimate heart rate from pulse rate reported by oscillometric method in atrial fibrillation: The value of pulse rate variation.

OBJECTIVES: To evaluate whether the mean pulse rate (PR) from three oscillometric blood pressure (BP) measurements provides an accurate estimation of electrocardiogram ventricular rate (HR) in patients with permanent atrial fibrillation (AF). METHODS: BP and PR were measured with an oscillometric BP device for three times with one-minute interval. Simultaneously, one-minute electrocardiogram was also recorded for three times. The first PR and HR values were recorded as PR1 and HR1, and the averages of three PR and HR values as mean PR (mPR) and mean HR (mHR). Meanwhile, the differences between the highest and lowest values among the three PR and HR were calculated as ΔPR and ΔHR. Furthermore, the patients were stratified on ΔPR into the 0-15 and >15 subgroups. RESULTS: A moderate positive correlation existed between PR1 and HR1 or mPR and mHR, and Bland-Altman plot also showed quite wide 95% limits between them. Meanwhile, ΔPR was significantly higher than ΔHR (12.1±8.6 vs 3.6±2.5bpm, P<0.001). However, in the 0-15 subgroup, the correlation between mPR and mHR was high (R2=0.800), and the 95% limits were only from -11.3 to 14.2bpm with a difference of 1.4bpm. The coincidence (mPR-mHR<10bpm) rate was 93.9% when PR≤80bpm, 96.3% when PR 81-100bpm, and 88.9% when PR over 100bpm. CONCLUSION: The average of three PR values reported by an oscillometric BP device could provide a clinically accepted estimation of mean HR of 3min in AF patients with ΔPR 0-15bpm and mean PR ≤100bpm.

Valuation of Normal Range of Ankle Systolic Blood Pressure in Subjects with Normal Arm Systolic Blood Pressure.

SUBJECT: This study aimed to establish a normal range for ankle systolic blood pressure (SBP). METHODS: A total of 948 subjects who had normal brachial SBP (90-139 mmHg) at investigation were enrolled. Supine BP of four limbs was simultaneously measured using four automatic BP measurement devices. The ankle-arm difference (An-a) on SBP of both sides was calculated. Two methods were used for establishing normal range of ankle SBP: the 99% method was decided on the 99% reference range of actual ankle BP, and the An-a method was the sum of An-a and the low or up limits of normal arm SBP (90-139 mmHg). RESULTS: Whether in the right or left side, the ankle SBP was significantly higher than the arm SBP (right: 137.1 ± 16.9 vs 119.7 ± 11.4 mmHg, P<0.05). Based on the 99% method, the normal range of ankle SBP was 94~181 mmHg for the total population, 84~166 mmHg for the young (18-44 y), 107~176 mmHg for the middle-aged(45-59 y) and 113~179 mmHg for the elderly (≥ 60 y) group. As the An-a on SBP was 13 mmHg in the young group and 20 mmHg in both middle-aged and elderly groups, the normal range of ankle SBP on the An-a method was 103-153 mmHg for young and 110-160 mmHg for middle-elderly subjects. CONCLUSION: A primary reference for normal ankle SBP was suggested as 100-165 mmHg in the young and 110-170 mmHg in the middle-elderly subjects.

Impact of nitric oxide on adrenomedullin- and proadrenomedullin N-terminal 20 peptide-induced cardiac responses: action by alone and combined administration.

The cardiac effects of adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) as well as the possible signaling pathways were investigated. In the isolated perfused rat heart, infusion of AM (10(-11) to 10(-8) M) and PAMP(10(-11) to 10(-8) M) for 10 min, alone or in combination, induced concentration-dependent decreases in the left ventricular pressure (LVP), LVP +/- dp/dtmax of the hearts. The effects were attenuated by Nomega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase. ADM and PAMP alone or in combinations increased the coronary fluid (CF), which could be antagonized by L-NAME. Pretreatment of H89, an inhibitor of protein kinase A (PKA), failed to alter the AM- or PAMP-induced decreases in LVP and LVP +/- dp/dtmax, but further promoted the AM or PAMP increased CF. The cAMP content in left cardiac ventricle was increased significantly by ADM infusions but not by PAMP. There was no statistical difference in cAMP contents with ADM administrated alone from those combined with ADM and PAMP. In conclusion, this study reveals that ADM and PAMP infused alone or in combinations inhibited the function of rat hearts in vitro, which may be partly involved with the NOS/NO pathway, rather than cAMP/PKA.

Phospholipase A2 inhibits nuclear nucleoside triphosphatase activity and mRNA export in isolated nuclei from rat liver.

The present study is undertaken to investigate whether the phospholipase A(2) (PLA(2)) influences mRNA nucleocytoplasmic transport evaluated by nucleoside triphosphatase (NTPase) activity and mRNA export in isolated hepatic nuclear envelope. Isolated hepatic nuclei from rat liver were exposed to PLA(2) (10(-5) approximately 10(-2)/ml) with or without incorporation of nuclei with phosphatidylcholine (PC) liposome. Messenger RNA exports and NTPase activities of nuclear membrane were assayed using ATP and GTP as substrates. We found that the RNA efflux, evaluated by [3H] uridine, was potently decreased in a concentration-dependent manner, by incubation of hepatic nuclei with PLA(2), regardless using ATP or GTP as substrates. The PC content in nuclear membrane was also decreased by PLA(2)-treatment. The PC was incorporated into the nuclear membrane by addition of phospholipid liposomes into the incubation mixture. PC incorporation into the nuclear membrane did not alter mRNA export. However this resulted in a significant increase in mRNA export rate in PLA(2)-treated group. Messenger RNA export rate in PLA(2) (10(-3) unit/mL)- treated nuclear membrane was positively correlated with level of PC incorporation, both using ATP and GTP as substrates. The activity of nucleoside triphosphatase, a nuclear membrane-associated enzyme, showed parallel variations with mRNA transport. It is concluded that nuclear PLA(2) plays a regulatory role in RNA transport, which can be antagonized by exogenous PC. These might be pathophysiologically significance, although the mechanisms by which this effect takes place remain to be clarified.

Protective effect of taurine on hypochlorous acid toxicity to nuclear nucleoside triphosphatase in isolated nuclei from rat liver.

AIM: Taurine has been shown to be an effective scavenger of hypochlorous acid (HOCl). The role of HOCl is well established in tissue damage associated with inflammation and injury. In the present study, the effect of HOCl on nuclear nucleoside triphosphatase of hepatocytes and the ability of taurine to prevent this effect were investigated. METHODS: Isolated hepatic nuclei from rat liver were exposed to HOCl with or without taurine. The NTPase activity on nuclear envelope was assayed using ATP and GTP as substrates, respectively. RESULTS: The first series of experiments evaluated the toxicity of HOCl and the efficacy of taurine to protect NTPase. HOCl at 10(-9)-5 x 10(-6) mol/L reduced nuclear NTPase activities in a concentration dependent manner (ATP and GTP as substrates) (P<0.01). HOCl at 10(-6) mol/L reduced the NTPase activity by 65% (ATP as substrate) and 76% (GTP as substrate). Taurine (10(-7) to 10(-4) mol/L) was tested for protection against HOCl at 10(-6) mol/L and the nuclei treated with 5 x 10(-4) mol/L taurine exhibited only 20% and 12% reduction in NTPase activities compared to untreated controls. A second study was performed comparing taurine to glutathione (GSH). GSH and HOCl at 10(-6) mol/L exhibited 46% and 67.4% reduction in NTPase activities compared with control. GSH (10(-4) mol/L) which was incubated with the nuclei and HOCl still exhibited 44.2% and 44.8% reduction in NTPase activities of untreated control. Taurine with HOCl only exhibited 15.2% and 17.1% reduction in NTPase activities, which provided more powerful protection against HOCl than GSH. The third experiment was undertaken to evaluate the specificity of taurine against HOCl. Incubation of rat hepatic nuclei with Fe(3+)/H(2)O(2) (1 m mol/L vs 5 micromol/L) resulted in a decrease in nuclear NTPase activities (P<0.01). When hepatic nuclei were incubated with Tau (10(-4) mol/L) and Fe(3+)/H(2)O(2) (1m mol/L vs 5 micromol/L), nuclear NTPase activities were only slightly increased as compared with that of incubation with Fe(3+)/H(2)O(2) alone. However, GSH failed to alter the NTPase activities induced by Fe(3+)/H(2)O(2). CONCLUSION: The present findings indicate that HOCl can act as an inhibitor of nuclear NTPase. Taurine can antagonistically reduce the toxicity of HOCl to NTPase.

Levels of adrenomedullin and proadrenomedullin N-terminal 20 peptide in myocardium and aorta of spontaneously hypertensive rats and Wistar-Kyoto rats.

In this study, we observed the levels of adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) in myocardium and aorta of spontaneously hypertensive rats (SHRs) in comparison with Wistar-kyoto (WKY) rats. Contents of ADM and PAMP were measured by radioimmunoassay (RIA) in plasma, myocardium and aorta. The amount of Pro-ADM mRNA of myocardium and aorta was determined by competitive quantitative reverse transcription polymerase chain reaction (RT-PCR). In SHRs the amounts of Pro-ADM mRNA of myocardium and aorta were 66.7% (P<0.01) and 73% (P<0.01) higher than those in WKY rat, respectively. In SHRs, the levels of ADM in plasma, myocardium and aorta were 29%, 76.7% and 79% (all P<0.01) higher than those in WKY rats, respectively. The level of PAMP in SHRs was increased by 42.5% in plasma (P<0.01), 47.2% in myocardium (P<0.0.1) and 27.3% in aorta (P<0.05) compared to WKY rats, respectively. In addition, the ratio of ADM content to PAMP content in SHRs group was increased compared with that in WKY group (2.0+/-0.25 vs 1.64+/-0.3 and 2.2+/-0.18 vs 1.56+/-0.28, in myocardium and aorta, respectively, P<0.01). These results suggest that ProADM gene expression is up-regulated and the increase in ADM and PAMP is different in SHRs. The significance of inconsistency of increase in ADM and PAMP in SHRs needs to be further investigated.