Paternal age at birth and metabolic risk factors in adolescents: a nationwide survey.

OBJECTIVE: The aim of the study is to examine associations between paternal age at childbirth and offspring cardiovascular risk factors in adolescence. STUDY DESIGN: This is a cross-sectional study. METHODS: Data from the 2007-2016 Korea National Health and Nutrition Examination Survey was used. A total of 4,096 adolescents were included in the final analysis, and their information on blood pressure, fasting glucose level, and lipid profile was collected. Multiple linear regression models were applied to evaluate the effect of paternal age on cardiovascular risk factors with adjustment for potential confounders. RESULTS: The median age of participants was 13 years, and 53.2% were male. Maternal and paternal ages were closely correlated with each other, and older parents had older offspring. Paternal age was positively associated with levels of total cholesterol (p = 0.033) and triglycerides (p = 0.042) after adjusting for confounders. CONCLUSION: This nationwide study shows that advanced paternal age is associated with a less favorable lipid profile in a dose-dependent manner.

The triglyceride-lowering effect of supplementation with dual probiotic strains, Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032: Reduction of fasting plasma lysophosphatidylcholines in nondiabetic and hypertriglyceridemic subjects.

BACKGROUND AND AIMS: This study evaluated the triglyceride (TG)-lowering effects of consuming dual probiotic strains of Lactobacillus curvatus (L. curvatus) HY7601 and Lactobacillus plantarum (L. plantarum) KY1032 on the fasting plasma metabolome. METHODS AND RESULTS: A randomized, double-blind, placebo-controlled study was conducted on 92 participants with hypertriglyceridemia but without diabetes. Over a 12-week testing period, the probiotic group consumed 2 g of powder containing 5 × 10(9) colony-forming units (cfu) of L. curvatus HY7601 and 5 × 10(9) cfu of L. plantarum KY1032 each day, whereas the placebo group consumed the same product without probiotics. Fasting plasma metabolomes were profiled using UPLC-LTQ-Orbitrap MS. After 12 weeks of treatment, the probiotic group displayed a 20% reduction (p = 0.001) in serum TGs and 25% increases (p=0.001) in apolipoprotein A-V (apoA-V). At the 12-week follow-up assessment, the following 11 plasma metabolites were significantly reduced in the probiotic group than the placebo group: palmitoleamide, palmitic amide, oleamide, and lysophosphatidyl choline (lysoPC) containing C14:0, C16:1, C16:0, C17:0, C18:3, C18:2, C18:1, and C20:3. In the probiotic group, changes (▵) in TG were negatively correlated with ▵ apoA-V, which was positively correlated with ▵ FFA. In addition, ▵ FFA was strongly and positively correlated with ▵ lysoPCs in the probiotic group but not the placebo group. CONCLUSIONS: The triglyceride-lowering effects of probiotic supplementation, partly through elevated apoA-V, in borderline to moderate hypertriglyceridemic subjects showed reductions in plasma metabolites, fatty acid primary amides and lysoPCs (NCT02215694; http://www.clinicaltrials.gov). Clinical trials: NCT02215694; http://www.clinicaltrials.gov.

Atherogenic dyslipidaemic profiles associated with the development of Type 2 diabetes: a 3.1-year longitudinal study.

AIMS: While there is thought to be an association between glucose and lipid metabolism, it is largely unknown whether apolipoprotein B and non-high density lipoprotein (HDL) cholesterol are associated with the development of Type 2 diabetes. It is also unknown whether these atherogenic dyslipidaemic profiles have a stronger association with diabetes risk compared with conventional lipid measurements. METHODS: A total of 118 429 subjects without diabetes (70 980 men and 47 449 women), aged 17-90 years (mean age 39.6 years), were enrolled in this study and followed for a mean duration of 3.1 years. RESULTS: Apolipoprotein B and non-HDL cholesterol levels showed a strong association with the development of Type 2 diabetes compared with conventional lipid measurements and their ratios [hazard ratio per 1 sd; 1.39 (95% CI 1.37-1.42) and 1.38 (95% CI 1.35-1.40), respectively; both P < 0.001]. The Kaplan-Meier survival curve demonstrated that Type 2 diabetes developed more frequently as apolipoprotein B or non-HDL cholesterol levels increased across quartiles (both P < 0.001). In multivariate Cox regression analyses, both apolipoprotein B and non-HDL cholesterol were associated with the development of Type 2 diabetes, independent of other risk factor including age, sex, waist circumference, family history of diabetes, fasting serum glucose and insulin levels, HbA1c , systolic blood pressure and other conventional lipid measurements [hazard ratio per 1 sd; 1.14 (95% CI 1.11-1.18) and 1.13 (95% CI 1.10-1.16), respectively; both P < 0.001]. CONCLUSIONS: Atherogenic dyslipidaemia was more strongly associated with the development of Type 2 diabetes than conventional lipid measurements, and this effect was independent of other well-established risk factor for diabetes.

Effect of the G-protein ß3 subunit 825T allele on the change of body adiposity in obese female.

No clinical studies on the lipolytic effect of guanine nucleotide-binding protein ß3 subunit gene (GNB3) 825T polymorphism have been performed. This study was a subinvestigation of a 12-week randomized controlled trial (NCT01184560) for the additive effect of orlistat on sibutramine treatment. The analysis involved 101 obese females aged 18-49 years, genotyped at the GNB3 825 locus. To exclude any influence from potential confounders, we used an analysis of covariance model. After the intervention, fat mass proportion in total weight loss was significantly lower in subjects with a T allele than in those without a T allele (p = 0.034). GNB3 825T allele was associated with blunted fat mass reduction in obese females.

Increased apoB/A-I ratio independently associated with Type 2 diabetes mellitus: cross-sectional study in a Korean population.

AIMS: The aim of this study was to investigate whether increased apolipoprotein B/apolipoprotein A-I ratio is associated with Type 2 diabetes mellitus independent of other risk factors for Type 2 diabetes. METHODS: A total of 70,063 subjects (41,391 men and 28,672 women; mean age 41.5 years) who visited the Health Screening Center at Kangbuk Samsung Hospital for a routine medical check-up between January 2009 and December 2009 were enrolled in this study. RESULTS: The mean apolipoprotein B/apolipoprotein A-I ratio in the study subjects was 0.66 ± 0.18. The prevalence of Type 2 diabetes increased across the apolipoprotein B/apolipoprotein A-I ratio quartiles (1.0%, 1.6%, 2.9%, and 4.8% for the 1st through 4th quartiles, respectively, P < 0.001) and homeostasis model assessment-insulin resistance (HOMA2-IR) also showed an increasing tendency by quartile (P < 0.001). The apolipoprotein B/apolipoprotein A-I ratio was correlated with age, adiposity, blood pressure, HOMA2-IR value, fasting glucose levels, and other inflammatory marker, including high-sensitivity C-reactive protein, and lipoprotein (a) levels (all P < 0.001). In a multiple logistic regression model, the highest apolipoprotein B/apolipoprotein A-I ratio quartile was associated with Type 2 diabetes, even after controlling for other risk factors for diabetes, such as age, gender, BMI, systolic blood pressure, HOMA2-IR values, high-sensitivity C-reactive protein levels, family history of diabetes, presence of metabolic syndrome, and conventional lipid parameters (odds ratio 1.31; 95% confidence interval 1.17-1.46, P < 0.001). CONCLUSIONS: The apolipoprotein B/apolipoprotein A-I ratio was found to be associated with Type 2 diabetes independent of other risk factors for diabetes and conventional lipid parameters.

Serum 1,5-anhydroglucitol is associated with diabetic retinopathy in Type 2 diabetes.

AIMS: To determine whether there is a relationship between 1,5-anhydroglucitol (1,5-AG), a marker of postprandial hyperglycaemia and glycaemic variability, and the presence of diabetic retinopathy and albuminuria in patients with Type 2 diabetes. METHODS: Five hundred and sixty-seven patients with Type 2 diabetes (serum creatinine < 133 µmol/l), who were enrolled in the Seoul Metro-City Diabetes Prevention Program (SMC-DPP), were cross-sectionally assessed by multivariate logistic regression analysis. RESULTS: After controlling for age, sex, binary HbA(1c) levels, duration of diabetes, triglyceride, systolic blood pressure, smoking status, history of hypertension and dyslipidaemia, and the use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker medication, the odds ratios (95% CI) of diabetic retinopathy were 2.86 (1.12-7.25) for the first (lowest) quartile of 1,5-anhydroglucitol, 2.87 (1.25-6.61) for the second quartile and 0.88 (0.35-2.22) for the third quartile compared with the fourth quartile (P for trend = 0.010). Conversely, the associations between 1,5-anhydroglucitol and clinical albuminuria were non-significant after adjustment. Subjects with low 1,5-anhydroglucitol (< 10.0 µg/ml) were more likely to experience diabetic retinopathy than those with high 1,5-anhydroglucitol (≥ 10.0 µg/ml) under moderate glucose control (HbA(1c) < 8%, 64 mmol/mol) and there were no significant differences in the prevalence of diabetic retinopathy between the subgroup with HbA(1c) < 8% (64 mmol/mol) and low 1,5-anhydroglucitol and the subgroup with HbA(1c) ≥ 8% (64 mmol/mol). CONCLUSIONS: 1,5-Anhydroglucitol levels show close associations with diabetic retinopathy, especially among patients under moderate glucose control, but not with albuminuria. These results suggest that 1,5-anhydroglucitol might be a complementary marker for targeting higher risk group.

Treatment guidelines for isolated dissection of the superior mesenteric artery based on follow-up CT findings.

OBJECTIVES: The treatment guidelines for isolated superior mesenteric artery dissection (SMAD) are not well established. The purpose of this study was to report a single-centre series of SMAD and propose treatment guidelines. MATERIALS AND METHODS: Between November 2004 and December 2009, 30 patients were diagnosed with SMAD. We retrospectively reviewed their medical records. RESULTS: The subjects included 26 men and four women, with a mean age of 55.1 years. The chief complaint was abdominal pain in 17 patients, whereas 13 patients were asymptomatic. The mean follow-up was 38.3 months. The radiographic findings included intimal flap with a false lumen in 20 patients and intramural haematoma in 10 patients. The treatments included observation in 18 patients, anticoagulation in five patients, stenting in six patients and surgery in one patient. During follow-up (mean 15.6 months), there was no change in the computed tomography scans of seven patients, improvement was observed in four patients and complete resolution was observed in four patients. All patients, including the symptomatic patients, remained asymptomatic during follow-up. CONCLUSIONS: Most patients with SMAD can be successfully managed with conservative treatment. Surgical treatment or percutaneous intervention can be reserved for patients with severe mesenteric ischaemia and those for whom the initial conservative treatment fails.

Weight gain within the normal weight range predicts ultrasonographically detected fatty liver in healthy Korean men.

OBJECTIVES: We performed a prospective study to determine whether weight gain predicts future ultrasonographically detected fatty liver (USFL) in a lean adult population. METHODS: Among 15,347 Korean male workers, aged 30-59 years, who participated in a health check-up programme in 2002, a USFL-free cohort of 4246 non-diabetic men was followed until September 2007. Alcohol consumption was assessed by a questionnaire. Weight change for each subject was calculated as the difference between baseline and subsequent measurements. Biochemical tests for liver and metabolic function were done. The primary outcome was ultrasound-diagnosed fatty liver. A standard Cox proportional hazards model and time-dependent Cox model were performed. RESULTS: During 16,829.7 person-years of follow-up, 622 participants developed USFL. After adjusting for age, the period from visit 1 to visit 2, BMI, HDL-C, triglyceride, uric acid, alanine aminotransferase, and HOMA-IR, the risk for USFL increased with increasing quartiles of weight change (p for trend <0.001). This association remained significant when weight change and covariates, except age and the period from visit 1 to visit 2, were modelled as time-dependent variables. Subjects in the fourth quartile (weight gain > or =2.3 kg) were at significantly elevated risk for USFL (adjusted hazard ratio (aHR), 1.26; 95% CI, 1.01 to 1.58). These associations did not change, even in normal weight men with a baseline BMI between 18.5 and 22.9 kg/m(2) (n = 2186). CONCLUSION: Weight gain per se appears to increase the risk for developing USFL. Thus, avoiding weight gain, even among lean adult individuals, can be helpful in preventing this disease.

Association Between Aerobic Exercise and Handgrip Strength in Adults: A Cross-Sectional Study Based on Data from the Korean National Health and Nutrition Examination Survey (2014-2017).

OBJECTIVES: Handgrip strength is an easy-to-assess indicator of overall muscle strength and can be used to evaluate health status. Although previous studies have reported an increase in grip strength due to aerobic exercise, such a study has not been conducted on Korean participants. This study aimed to investigate the effects of aerobic exercise on handgrip strength and examine the association between these two variables in Korean patients with hypertension or diabetes. DESIGN: Cross-sectional study. SETTING: This study used data from the 6th and 7th Korean National Health and Nutrition Examination Survey (2014-2017). PARTICIPANTS: A total of 19,650 individuals aged ≥19 years who had responded to questionnaires concerning aerobic exercise and handgrip strength were analyzed. MEASUREMENTS: The relationship between aerobic activity and handgrip strength was examined by logistic regression analysis. RESULTS: The mean age of individuals in the low muscle strength group was higher than that in the normal muscle strength group. The odds ratio for low handgrip strength was higher in individuals who did not perform aerobic exercise than in those who performed aerobic exercise. Following adjustment for covariates, the odds ratios (95% confidence intervals) for low handgrip strength were 1.415 (0.187-1.688) in the total sample, 1.799 (1.376-2.352) in patients with hypertension, and 1.811 (1.208-2.715) in patients with diabetes. CONCLUSION: The results of our study indicated a strong association between aerobic exercise and handgrip strength in the Korean population.

A new synthesis route to nanocrystalline olivine phosphates and their electrochemical properties.

LiFePO4 nanoparticles were synthesized in various polyol mediums without any further heating. The LiFePO4 samples synthesized in polyol mediums exhibited average sizes of 20, 20, 50, and 50 nm with orthorhombic-like shapes. The XRD patterns were indexed on the basis of an olivine structure (space group : Pnma) except for the sample prepared in EG polyol medium. The LiFePO4 samples prepared in EG, DEG, TEG, and TrEG polyol mediums show the reversible capacity of 120 mA h/g, 144 mA h/g, 159 mA h/g, and 167 mA h/g at current density of 0.1 mA/cm2 with no capacity fading and excellent cycle retentions during extended cycles. Especially, the samples showed the excellent performances at high rate of 30 C and 60 C with high capacity retention. It is a speculation that nanometer size materials (approximately 50 nm) and a uniform size-distribution with highly crystallined phase may affect the excellent performances at high rate current densities.

Epigallocathechin-3 gallate selectively inhibits the PDGF-BB-induced intracellular signaling transduction pathway in vascular smooth muscle cells and inhibits transformation of sis-transfected NIH 3T3 fibroblasts and human glioblastoma cells (A172).

Enhanced activity of receptor tyrosine kinases such as the PDGF beta-receptor and EGF receptor has been implicated as a contributing factor in the development of malignant and nonmalignant proliferative diseases such as cancer and atherosclerosis. Several epidemiological studies suggest that green tea may prevent the development of cancer and atherosclerosis. One of the major constituents of green tea is the polyphenol epigallocathechin-3 gallate (EGCG). In an attempt to offer a possible explanation for the anti-cancer and anti-atherosclerotic activity of EGCG, we examined the effect of EGCG on the PDGF-BB-, EGF-, angiotensin II-, and FCS-induced activation of the 44 kDa and 42 kDa mitogen-activated protein (MAP) kinase isoforms (p44(mapk)/p42(mapk)) in cultured vascular smooth muscle cells (VSMCs) from rat aorta. VSMCs were treated with EGCG (1-100 microM) for 24 h and stimulated with the above mentioned agonists for different time periods. Stimulation of the p44(mapk)/p42(mapk) was detected by the enhanced Western blotting method using phospho-specific MAP kinase antibodies that recognized the Tyr204-phosphorylated (active) isoforms. Treatment of VSMCs with 10 and 50 microM EGCG resulted in an 80% and a complete inhibition of the PDGF-BB-induced activation of MAP kinase isoforms, respectively. In striking contrast, EGCG (1-100 microM) did not influence MAP kinase activation by EGF, angiotensin II, and FCS. Similarly, the maximal effect of PDGF-BB on the c-fos and egr-1 mRNA expression as well as on intracellular free Ca2+ concentration was completely inhibited in EGCG-treated VSMCs, whereas the effect of EGF was not affected. Quantification of the immunoprecipitated tyrosine-phosphorylated PDGF-Rbeta, phosphatidylinositol 3'-kinase, and phospholipase C-gamma1 by the enhanced Western blotting method revealed that EGCG treatment effectively inhibits tyrosine phosphorylation of these kinases in VSMCs. Furthermore, we show that spheroid formation of human glioblastoma cells (A172) and colony formation of sis-transfected NIH 3T3 cells in semisolid agar are completely inhibited by 20-50 microM EGCG. Our findings demonstrate that EGCG is a selective inhibitor of the tyrosine phosphorylation of PDGF-Rbeta and its downstream signaling pathway. The present findings may partly explain the anti-cancer and anti-atherosclerotic activity of green tea.

Synthesis and secretion of mucous glycoprotein by the gill of Mytilus edulis. I. Histochemical and chromatographic analysis of [14C]glucosamine bioincorporation.

The ability of the isolated gill epithelium of Mytilus edulis to incorporate [14C]glucosamine as a precursor in the biosynthesis and secretion of mucous glycoproteins was investigated. Localization of mucous cells in the gill filament was achieved using histochemical staining techniques. Mucus cells containing neutral and acidic mucins were found in the lateral region, whereas mucus cells containing primarily neutral or sulfated mucins were found in the abfrontal region. Autoradiographic results showed that in both regions, the mucous cells were rich in content of the incorporated radiolabel. The secreted glycoproteins containing the incorporated radiolabel were analyzed by column chromatography using Bio-Gel P-2 and P-6. Two populations of the glycoproteins differing in molecular size were isolated. Upon alkaline reductive borohydride cleavage of the O-glycosidic linkages of the high molecular weight protein, about 70% of the radiolabel and 85% of the carbohydrate content were removed from the protein. The alkaline borohydride cleavage resulted in the formation of at least six oligosaccharide chains of various lengths of sugar units. Gas chromatographic analysis of the carbohydrate composition shows that the glycoproteins contain N-acetylglucosamine, N-acetylgalactosamine, and galactose, fucose, and mannose as the neutral monosaccharides. The above results indicate that the isolated gill epithelium of M. edulis is capable of incorporating [14C]glucosamine in the synthesis of secretable mucin-type glycoproteins.

Bypassing the kinetic trap of serpin protein folding by loop extension.

The native form of some proteins such as strained plasma serpins (serine protease inhibitors) and the spring-loaded viral membrane fusion proteins are in a metastable state. The metastable native form is thought to be a folding intermediate in which conversion into the most stable state is blocked by a very high kinetic barrier. In an effort to understand how the spontaneous conversion of the metastable native form into the most stable state is prevented, we designed mutations of alpha1-antitrypsin, a prototype serpin, which can bypass the folding barrier. Extending the reactive center loop of alpha1-antitrypsin converts the molecule into a more stable state. Remarkably, a 30-residue loop extension allows conversion into an extremely stable state, which is comparable to the relaxed cleaved form. Biochemical data strongly suggest that the strain release is due to the insertion of the reactive center loop into the major beta-sheet, A sheet, as in the known stable conformations of serpins. Our results clearly show that extending the reactive center loop is sufficient to bypass the folding barrier of alpha1-antitrypsin and suggest that the constrain held by polypeptide connection prevents the conversion of the native form into the lowest energy state.

Involvement of phospholipase D in oxidative stress-induced necrosis of vascular smooth muscle cells.

Phospholipase D (PLD) has been associated with necrosis. However, it is not clear whether PLD plays a causative role in this cellular process. We investigated the role of PLD in oxidative stress-induced necrosis of vascular smooth muscle cells (VSMCs). Pervanadate (hydrogen peroxide plus orthovanadate) but not hydrogen peroxide alone activated PLD in a dose- and time-dependent manner. Exposure of VSMCs to pervanadate resulted in necrosis. Pretreatment with butan-1-ol, a PLD inhibitor, attenuated both pervanadate-induced necrosis and increase of intracellular Ca(2+). Removal of extracellular Ca(2+) inhibited pervanadate-induced necrosis by 50%. These results suggest that PLD activation mediates pervanadate-induced necrosis of VSMCs, which is at least partly due to Ca(2+) toxicity.

Inhibitory effects of procaine on contraction and calcium movement in vascular and intestinal smooth muscles.

1. The effects of procaine on muscle tension and 45Ca2+ movements were investigated in vascular smooth muscle of the rabbit aorta and intestinal smooth muscle of the taenia isolated from guinea-pig caecum. 2. Procaine (10 mM) induced a contraction in the taenia but had little effect on the resting tension in the aorta. 3. Procaine, 0.5-10 mM, relaxed the sustained contractions induced by 65.4 mM KCl and 10(-6) M noradrenaline in the aorta, and by 45.4 mM KCl, 10(-6) M carbachol and 10(-6) M histamine in the taenia. The inhibitory effect of procaine on the high K+-induced contractions was antagonized by external Ca2+ but not by the Ca2+ channel activators, Bay K 8644 and CGP 28,392. 4. 45Ca2+ uptake was increased by high K+ or noradrenaline in the aorta and by high K+ or carbachol in the taenia. The increments were inhibited by procaine at the concentrations needed to inhibit the muscle contractions. 5. In a Ca2+-free solution, noradrenaline and caffeine induced a transient contraction in the aorta, whereas a second application of each stimulant was almost ineffective. Addition of 1-10 mM procaine shortly before the first application of the stimulant inhibited the contraction. After washing the muscle with a Ca2+-free solution without procaine, the second application of the stimulant induced a greater contraction than that in control muscle without procaine pretreatment. 6. Noradrenaline and caffeine released 45Ca2+ from a cellular site in the aorta. Procaine inhibited the effects of these stimulants. 7. It was concluded that procaine may inhibit both the opening of Ca2+ channels and the release of Ca2 + from cellular stores and the former but not the latter effect may be attributable to a local anaesthetic action.

Inhibitory effects of caffeine on contractions and calcium movement in vascular and intestinal smooth muscle.

1. The mechanism of the inhibitory effect of caffeine was investigated using vascular smooth muscle of rabbit aorta and intestinal smooth muscle of taenia isolated from guinea-pig caecum. 2. Caffeine, 0.5-10 mM, relaxed the sustained contraction induced by 65.4 mM KCl or 10(-6) M noradrenaline in aorta, and by 45.4 mM KCl or 10(-6) M carbachol in taenia. The inhibitory effect of caffeine on the high K+-induced contraction was antagonized by external Ca2+ but not by the Ca2 channel activators, Bay K 8644 (10(-7) M) or CGP 28,392 (10(-7) M). Forskolin (2 x 10(-7) M) potentiated the inhibitory effect of caffeine on the noradrenaline-induced contraction but not on the high K+- or carbachol-induced contraction. Caffeine induced a time- and concentration-dependent increase in the cyclic AMP content of aorta and forskolin caused a further augmentation. 3. 45Ca2+ uptake was increased by high K+ or noradrenaline in aorta and by high K+ or carbachol in taenia. The increments were inhibited by caffeine at concentrations needed to inhibit muscle contractions. 4. 45Ca2+ in the cellular releasable site in aorta was decreased either by noradrenaline or by caffeine. Simultaneous application of noradrenaline and caffeine did not induce an additive decrease. 5. In aorta treated with a Ca2+-free solution, caffeine induced only a small contraction. Noradrenaline induced a greater contraction which was inhibited by caffeine. After washout of caffeine and noradrenaline, the second application of noradrenaline induced a transient contraction suggesting that caffeine does not deplete the noradrenaline-sensitive store. 6. It was concluded that caffeine has multiple sites of action in smooth muscle. Caffeine releases Ca2+ from a store which is apparently not sensitive to noradrenaline. Caffeine may inhibit noradrenalineinduced Ca2' release. Caffeine itself induces only a small contraction possibly because it decreases the Ca2+ sensitivity of contractile filaments and/or increases Ca2+ extrusion. Further, caffeine seems to inhibit stimulated Ca2+ influx. Cyclic AMP may be only partly responsible for the inhibitory effect of caffeine.

Cyclic AMP and cyclic GMP relax phorbol ester-induced contractions of rat aorta by different mechanisms.

This study was designed to test the hypothesis that 8-Br-cAMP and 8-Br-cGMP dependent relaxation of phorbol dibutyrate stimulated contractions of intact rat aorta are independent of changes in the level of myosin light chain phosphorylation. Phorbol dibutyrate stimulated contraction with a concomitant increase in myosin light chain phosphorylation in normal tissues and without an increase in myosin light chain phosphorylation in calcium-depleted tissues. Phorbol dibutyrate stimulated contractions in normal CaCl2-containing physiological salt solution were relaxed in a concentration-dependent manner by 8-Br-cAMP and 8-Br-cGMP. Phorbol dibutyrate-induced contractions in the absence of Ca2+ were only relaxed by 8-Br-cGMP; 8-Br-cAMP had no effect. The relaxation induced by 8-Br-cGMP was associated with a decrease in myosin light chain phosphorylation suggesting that cGMP-dependent protein kinase may alter the activity of either the myosin light chain kinase or phosphatase. The relaxation induced by 8-Br-cAMP was not associated with a decrease in phosphorylation suggesting that cAMP-dependent protein kinase may uncouple myosin light chain phosphorylation from force.

Vasodilating and hypotensive effects of fangchinoline and tetrandrine on the rat aorta and the stroke-prone spontaneously hypertensive rat.

Comparative studies of the effects of tetrandrine (TET) and fangchinoline (FAN), two major components of the Radix of Stephannia tetrandrae, on vasodilations and on calcium movement in vascular smooth muscle, and studies of hypotensive effects on stroke-prone spontaneously hypertensive rats (SHRSP) were performed in the following experiments. TET and FAN inhibited high K+ (65.4 mM) and induced sustained contraction in the rat aorta smooth muscle strips. IC50 values for TET and FAN were 0.27 +/- 0.05 microM (n = 6) and 9.53 +/- 1.57 microM (n = 6), respectively, and this inhibition was antagonized by increasing the Ca2+ concentration in the medium. The IC50 of TET for norepinephrine (NE)-induced contraction (0.86 +/- 0.04 g) was 3.08 +/- 0.05 microM (n = 4), and the IC50 of FAN for NE-induced contraction (0.88 +/- 0.07 g) was 14.20 +/- 0.40 microM (n = 4). At the molecular level, radiolabelled 45Ca2+ uptake tests revealed that TET and FAN also inhibited high K+ (65.4 mM) and 1 microM NE-stimulated Ca2+ influx in rat aorta strips at the maximal concentration was needed to inhibit the contraction. TET (3 mg/kg) and FAN (30 mg/kg) administered by intravenous (i.v.) bolus injection also lowered the mean arterial pressure (MAP) significantly during the period of observation in conscious SHRSP, respectively. These results showed that TET was more potent than FAN in blocking calcium channels and antihypertensive activity.