1181Role of rho-mdia1 signaling to maintain cardiac function in response to pressure overload in mice

Background

Cardiac hypertrophy is a compensatory response to pressure overload that leads to heart failure. Recent studies have shown that Rho signaling has crucial regulatory roles in actin cytoskeleton rearrangement during cardiac hypertrophic responses. Rho is rapidly activated in response to pressure overload, but the mechanisms by which Rho and its downstream proteins control actin dynamics during hypertrophic responses remain unclear.

Objective

To identify the essential roles of mDia1 (Rho-effector molecule) in pressure overload-induced ventricular hypertrophy.

Methods and results

Male wild-type (WT) and mDia1-knockout (mDia1KO) mice (10–12 weeks old) were subjected to transverse aortic constriction (TAC) or a sham operation. The heart weight/tibia length ratio, cardiomyocyte cross-sectional area, left ventricular wall thickness, and expression of hypertrophy-specific genes were significantly decreased in mDia1KO mice 3 weeks after TAC, and the mortality rate was higher at 12 weeks. Echocardiography and the pressure-volume loop indicated that mDia1 deletion increased the severity of heart failure 8 weeks after TAC. Microarray gene expression profiling showed that the induction of immediate early genes due to the TAC operation was significantly lower in mDia1KO mice than WT mice, as was the activation of extracellular signal-regulated kinase (ERK) and focal adhesion kinase (FAK). We examined the role of mDia1 in neonatal rat ventricular cardiomyocytes (NRVMs) exposed to mechanical stress. The siRNA-mediated silencing of mDia1 attenuated stretch-induced ERK and FAK phosphorylation, and gene expression of c-fos. Importantly, loss of mDia1 suppressed an increase in the F/G-actin ratio in response to pressure overload in the mice. In addition, increases in nuclear myocardin-related transcription factors (MRTFs) and serum response factor (SRF) were perturbed in response to pressure overload in mDia1KO mice and to mechanical stretch in mDia1 depleted NRVMs.

Conclusions

Rho-mDia1, through actin dynamics, plays critical roles in pressure overload-induced hypertrophy by regulating ERK and FAK phosphorylation and the transcriptional activity of MRTF-SRF.

4090Maximum standardized uptake value of pericardial fat for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis

Background

Cardiac sarcoidosis is a cause of epicarditis and sustained life-threatening ventricular arrhythmias. These arrhythmias occasionally arise from epicardial. Positron emission tomogramphy-comututed tomography (PET-CT) is useful for diagnosis with sarcoidosis. However, the usefulness for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis is unknown.

Objective

We hypothesized that the evaluation of pericardial fat inflammation could identify high-risk sarcoidosis patients for ventricular arrhythmias.

Methods

We enrolled 20 consecutive patients with cardiac sarcoidosis performed PET-CT between August 2016 and December 2018. In each case, we measured the maximum standardized uptake value (SUVmax) of pericardial fat around the left atrium, both ventricules, atrioventricular groove, and left main coronary.

Results

Seven patients experienced ventricular tachycardia (VT) or ventricular fibrillation (VF). VT/VF patients had significantly more complete right bundle branch block (P=0.035), larger left atrial dimension (P=0.021), larger left ventricular end-diastolic dimension (P=0.005), lower ejection fraction (P=0.007), and higher E/e' (P=0.004). SUVmax of pericardial fat in the roof of left atrium (LA) and left ventricular (LV) with VT/VF patients were significantly higher than non-VT/VF patients (LA: 1.63 vs 1.32, P=0.0311; LV: 1.84 vs 1.26, P=0.045). The cut-off values of SUVmax derived from the ROC curve in the roof of LA and LV are 1.47 and 1.59 respectively. The Kaplan Meire estimator showed that high SUVmax patients in the roof of LA had significantly more detection of NSVT.

Conclusions

Our results suggest the relationship between SUVmax and VT/VF occurrence in patients with cardiac sarcoidosis. The evaluateon of SUVmax may be useful for VT/VF risk stratification.

P1628Angiopoietin-like protein (Angptl) 2 secreted from epicardial adipose tissue induces atrial myocardial fibrosis

Background

Using excised human left atrial appendage samples, we previously demonstrated that epicardial adipose tissue (EAT) are highly associated with atrial myocardial fibrosis as a substrate of atrial fibrillation (AF). We also reported the relationship between Angptl2 in EAT and atrial fibrosis. However, the mechanism is not clear. The purpose is to clarify the mechanisms underlying the effect of EAT on the atrial myocardium.

Methods

Human peri-left atrial EAT and abdominal subcutaneous adipose tissue (SAT) samples were obtained from 6 cases (2 females, 70.2±13.2 years). 50 mg of EAT and SAT were quickly washed with PBS and centrifuged 1min at 1200rpm. After 3 times this procedures, adipose tissues were cultured in DMEM F12 medium with Fetal bovine Serum (FBS) overnight.

After pre-incubation, EAT and SAT tissues were washed and centrifuge d three times and cultured in medium without FBS for 24hours. Finally, we collected oozed medium (conditioned medium) and used for experiments.

Concentrations of Angptl2 in conditioned medium were measured by ELISA.

To study the effects of conditioned medium, we used “organo-culture” system. Isolated atrium from 8week old male Sprague-Dawley rats were placed on the porous membrane with the endothelial face toward the membrane. After that, loading medium (conditioned medium:culture medium = 1:4), culture medium (control), or recombinant Angptl2 were dropped onto the epicardial face of the atrium once a day and incubated for 7 days (37°C, 5% CO2).

Then, histological and immunohistochemical analysis were performed. We also performed quantitative reverse transcription–polymerase chain reaction (RT–PCR) analysis.

Next, we isolated and cultured neonatal rat fibroblast and loaded Angptl2 for 24 hours.After collected these cells, we performed western blotting analysis.

Results

Atria organo-culture incubated for 7 days with conditioned medium showed global fibrosis. At epicardial side, fibrotic area of EAT group was significantly greater compared to that of SAT and control group (P<0.05).

mRNA of Col1a1, col3a1 and TGFβ1 were significantly increased in EAT group compared with the SAT and control group.

And, the concentration of conditioned medium created from EAT was significant higher than that from SAT (P<0.05).

Then, we dropped 500 ng/ml of recombinant Angptl2 onto the rat atria. Fibrotic area of Angptl22 group significantly greater than that of control with increasing number of α-SMA positive cells, and mRNA of col3a1 and TGFβ1 were significantly increased in Angptl2 group compared with control group.

In cultured fibroblasts, α-SMA and p-ERK expression were increased in Angptl2 group measured by western blotting analysis.

Conclusions

Our results demonstrated that EAT rather than SAT induces atrial myocardial fibrosis. There is a possibility that Angptl2 effused from EAT plays a part in atrial fibrosis thought EAT paracrine effect.

Acknowledgement/Funding

ONO PHARMACEUTICAL CO

Development of new osteonecrosis in systemic lupus erythematosus patients in association with long-term corticosteroid therapy after disease recurrence

OBJECTIVES

Systemic lupus erythematosus (SLE) patients are at high risk of developing osteonecrosis, as they require corticosteroid therapy for life. The purpose of this study was to use periodic MRI analysis to clarify (1) the incidence of new osteonecrosis associated with long-term corticosteroid therapy in SLE patients, and (2) the risk factors for delayed osteonecrosis in SLE patients.

METHODS

We prospectively studied 291 joints (134 hips and 157 knees) in 106 SLE patients without osteonecrosis after initial corticosteroid therapy, with a mean follow-up period of 13.6 years and a follow-up rate of 71%. All patients had undergone periodic MRI examination of the hip and knee joints for >10 years.

RESULTS

New osteonecrosis developed in 6 joints (3%) and only occurred after SLE recurrence in association with increased corticosteroid doses (to>30 mg/day [p=0.008]). New lesions were delayed for a mean 5.9 years after initial corticosteroid administration. The mean time from SLE recurrence to appearance of new lesions was 6.2 months. SLE recurrence occurred in 131 joints (45%), while SLE was well controlled in 160 joints (55%).

CONCLUSIONS

We suggest that with respect to long-term effects, total cumulative dose and duration of corticosteroid therapy do not contribute to osteonecrosis. However, SLE recurrence is a risk factor for new osteonecrosis. We recommend MRI screening for osteonecrosis at SLE recurrence.

Effect of progesterone on recovery from nerve injury during leg lengthening in rats

We investigated the effect of progesterone on the nerve during lengthening of the limb in rats. The sciatic nerves of rats were elongated by leg lengthening for ten days at 3 mm per day. On alternate days between the day after the operation and nerve dissection, the progesterone-treated group received subcutaneous injections of 1 mg progesterone in sesame oil and the control group received oil only. On the fifth, tenth and 17th day, the sciatic nerves were excised at the midpoint of the femur and the mRNA expression level of myelin protein P0 was analysed by quantitative real time polymerase chain reaction. On day 52 nodal length was examined by electron microscopy, followed by an examination of the compound muscle action potential (C-MAP) amplitude and the motor conduction velocity (MCV) of the tibial nerve on days 17 and 52. The P0 (a major myelin glycoprotein) mRNA expression level in the progesterone-treated group increased by 46.6% and 38.7% on days five and ten, respectively. On day 52, the nodal length in the progesterone-treated group was smaller than that in the control group, and the MCV of the progesterone-treated group had been restored to normal. Progesterone might accelerate the restoration of demyelination caused by nerve elongation by activating myelin synthesis.

Improvement of blood pressure control in a hypertension clinic: a 10-year follow-up study

The objective of the study was to assess whether the publication of new guidelines, such as JNC VI 1997 and WHO/ISH 1999, and the development of new antihypertensive drugs have improved blood pressure (BP) control. A total of 150 patients (age 29-88, mean 66+/-11 years in 2001) who were followed at our hypertension clinic during 1991-2001 were retrospectively investigated. We compared the clinical characteristics of the patients in 2001 to those in 1991 and 1996, using the averaged BP determined at two occasions each year for our analysis. The average BP decreased during the 10 years between 1991 and 2001. When good BP control was defined as <140/90 mmHg, the rate of patients with good BP control increased from 31% in 1991 to 43% in 1996, and to 57% in 2001 (P<0.001 vs 1991). Both younger (< or =64 years) and older (> or =65 years) patients showed similar improvement during these 10 years. In 2001, satisfactory BP control (<130/85 mmHg) was achieved in 24% of younger patients, which was significantly higher than the achievement in 1991 (10%, P=0.02). This improvement occurred at the same time as an increase in the prescription of Ca antagonists and angiotensin II antagonist. The patients with improved BP control during these 10 years (n=50) showed lower body mass index (BMI) and serum total cholesterol levels in 2001 compared to persistently uncontrolled patients (n=54). Furthermore, the change in BMI during these 10 years was significantly less in the patients with improved BP control than in the persistently uncontrolled patients. In conclusion, BP control improved in the 10 years studied, and it seems to be attributable to the more frequent use of the newer drugs such as angiotensin II antagonists and Ca antagonists, to lifestyle modification and also to the growth in awareness of the importance of strict BP control.

Molecular cloning, expression, and site-directed mutations of oxidosqualene cyclase from Cephalosporium caerulens

A cDNA for oxidosqualene:lanosterol cyclase (OSLC) was cloned and sequenced from the fungus Cephalosporium caerulens, that produces a steroidal antibiotic, helvolic acid. A 2280 bp open reading frame encoded an M(r) 87078 protein with 760 amino acids. The cDNA was functionally expressed in the OSLC-deficient mutant GIL77 strain of Saccharomyces cerevisiae. A truncated recombinant enzyme (Delta49N) starting from the second methionine (M50) residue was completely inactive, suggesting that ca. 30 additional hydrophilic amino acid residues at the N-terminal are essential for the folding of the enzyme. Furthermore, the active site residues, H234 and D456 (numbering in S. cerevisiae OSLC), were chosen for site-directed mutagenesis experiments; H234E, H234Y, H234F, D456E, D456N, and D456H mutants were inactive, while H234W and H234K mutants retained lanosterol-forming activity.

Magnesium decreases arterial pressure and inhibits cardiovascular responses induced by N-methyl-D-aspartate and metabotropic glutamate receptors stimulation in rostral ventrolateral medulla

OBJECTIVE

Magnesium sulfate (MgSO4) is widely used for the treatment of eclampsia. However, effects of Mg2+ in central cardiovascular regulation remain unclear. In the present study, the role of Mg2+ on cardiovascular regulation in the rostral ventrolateral medulla (RVLM) of rats was examined.

METHODS

Adult male Wistar rats were anesthetized with urethane, and artificially ventilated. The ventral surface of the medulla was exposed, and the RVLM was identified by microinjection (50 nl) of l-glutamate (l-Glu; 2 nmol). Then, MgSO4 (1, 3, 10 nmol, n = 7 for each dose) and magnesium chloride (MgCl2; 10 nmol, n = 7) were microinjected into the RVLM. l-Glu (2 nmol), N-methyl-D-aspartate (NMDA; 20 pmol), alpha-amino-3-hydroxy-5-methyl isoxazole-4-propionic acid (AMPA; 5 pmol) and (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid [(1S,3R)-ACPD, metabotropic glutamate receptor agonist; 1 nmol] were also microinjected with or without pretreatment of MgSO4 (10 nmol; n = 7 for each drug).

RESULTS

MgSO4 dose-dependently decreased mean arterial pressure (MAP) and heart rate (HR). The high dose of MgSO4 (10 nmol) significantly decreased MAP and HR (-25 +/- 4 mmHg and -43 +/- 6 bpm). Similarly, MgCl2 decreased MAP and HR (-27 +/- 4 mmHg and -30 +/- 6 bpm). The pressor response evoked by NMDA or (1S,3R)-ACPD was significantly attenuated by the pretreatment with MgSO4. In contrast, pressor response caused by l-Glu or AMPA was not affected by pretreatment with MgSO4.

CONCLUSIONS

These results suggest that Mg2+ has an inhibitory role on the RVLM neurons, and inhibits cardiovascular responses induced by NMDA and metabotropic glutamate receptor agonists.

Osteonecrosis in patients with systemic lupus erythematosus develops very early after starting high dose corticosteroid treatment

OBJECTIVES

To investigate the actual time of onset of osteonecrosis (ON) after high dose corticosteroid treatment in systemic lupus erythematosus (SLE).

METHODS

72 patients with active SLE, who received high dose corticosteroid for the first time, for the development of ON at hips and knees were monitored by magnetic resonance imaging for at least 12 months.

RESULTS

ON lesions were detected in 32/72 patients (44%) between one and five months (3.1 months on average) after starting high dose corticosteroid treatment. No osteonecrotic lesion was newly detected from the sixth month of treatment until the end of the follow up period.

CONCLUSION

The findings suggested that the actual time of onset of ON in SLE is within the first month of high dose corticosteroid treatment.

Association of body mass index with blood pressure in 80-year-old subjects

OBJECTIVE

Little data are available on the association between obesity and high blood pressure in elderly individuals, particularly in subjects over 80 years of age. The aim of the present study was to determine the association between body mass index (BMI) and blood pressure in 80-year-old subjects.

METHODS

This study was part of the 8020 Data Bank Survey, which was designed to collect the baseline data of systemic and dental health conditions in 80-year-old subjects. We studied the cross-sectional association of BMI with blood pressures in 645 Japanese (258 men and 387 women), who were 80 years old.

RESULTS

Mean systolic blood pressure rose from 146.6 mmHg in the first quintile of BMI to 147.5 mmHg in the second, 150.3 mmHg in the third, 151.6 mmHg in the fourth, and 156.4 mmHg in the fifth quintiles (test for trend, P = 0.006). Mean diastolic blood pressure rose from 75.8 mmHg in the lowest quintile of BMI to 81.8 mmHg in the highest (test for trend, P = 0.002). We performed multiple regression analysis, controlling for factors known to influence blood pressure values, such as sex, alcohol intake, current smoking status and serum glucose, total cholesterol and creatinine concentrations. The association between BMI and systolic and diastolic blood pressure, respectively, was highly statistically significant in all analyses.

CONCLUSION

These results show that a close relationship is present between obesity and high blood pressure, even in very old subjects.

Central human cocaine- and amphetamine-regulated transcript peptide 55-102 increases arterial pressure in conscious rabbits

We determined cardiovascular and neurohormonal responses to intracerebroventricular administration of human cocaine- and amphetamine-regulated transcript (CART) peptide 55-102 in conscious rabbits. Intracerebroventricular injection of CART 55-102 elicited dose-related increases in mean arterial pressure and renal sympathetic nerve activity. Peak values of mean arterial pressure and renal sympathetic nerve activity induced by intracerebroventricular injection of 1 nmol of CART 55-102 (+5.0+/-2.6 mm Hg and +72.5+/-20.8%) were obtained 40 and 60 minutes after injection, respectively. Plasma epinephrine and glucose concentrations significantly increased 30 and 60 minutes after intracerebroventricular injection of CART 55-102 (control versus 60 minutes for epinephrine, 77.0+/-62.4 versus 1067.5+/-329.3 pg/mL, P<0.01; for glucose, 6.25+/-0.33 versus 11.57+/-0.93 mmol/L, P<0.01). Plasma norepinephrine concentrations also significantly increased at 30 minutes. Plasma insulin, vasopressin, and cortisol concentrations increased at 60 minutes but did not attain significant values. However, pretreatment with intravenous injection of pentolinium (5 mg/kg), a ganglion-blocking agent, eliminated these cardiovascular and neurohormonal responses. In contrast, intravenous injection of the same dosage of CART 55-102 (1 nmol) as that used in the intracerebroventricular experiment failed to cause any cardiovascular and renal sympathetic nerve responses. These results suggest that intracerebroventricular human CART 55-102 acts in the central nervous system and activates sympathoadrenal outflow, which results in increases in arterial pressure and plasma glucose levels in conscious rabbits.

Altered diurnal variation of blood pressure in elderly subjects with decreased activity of daily living and impaired cognitive function

Activity of daily living (ADL) and cognitive are indices of physical and psychological activity in elderly subjects. The present study was performed to clarify the relationship among ADL, cognitive function, and ambulatory blood pressure (ABP) in the elderly. Study subjects were 77 females and 22 males (aged 60 to 101 years) with various levels of ADL and cognition, who were in nursing homes or geriatric hospitals. ABP was recorded every 30 min for 24 h by a noninvasive device. Mini-mental state examination (MMSE) and Barthel index measurement were used to evaluate cognitive function and ADL, respectively. Both the MMSE and Barthel index values showed a significant positive correlation with daytime ABP but not with nighttime ABP. The dip in nighttime BP correlated negatively with age, and positively with MMSE and Barthel index. In the multiple regression analysis, age and Barthel index values remained significant determinants of the dip in nighttime BP. Presence of stroke and MMSE became significant when the Barthel index values were removed from the analyses. When subjects were classified by tertiles of MMSE or Barthel index, subjects in the lowest MMSE group and those in the lowest Barthel index group had both lower daytime ABP and smaller nighttime BP dip than those of the other groups. A low BP level during the daytime was associated with altered diurnal variation of BP in elderly subjects with greater age, impaired cognitive function, and/or decreased ADL. ADL had a greater influence on diurnal BP variation than did cognitive function.

Lack of association between QT dispersion and blood pressure response during dental surgery

1. It is well known that dental surgery induces increases in blood pressure. However, the factors influencing this increase are not yet fully understood. We have determined the relationship between QTc (= QT/RR(1/2), with RR being the R-R interval in seconds) dispersion, measured with a 12-lead surface electrocardiogram, and changes in blood pressure during tooth extraction. 2. Both QTc dispersion and the power spectrum of R-R variability were determined before the dental surgery was undertaken. The low-frequency (LF; 0.041-0.140 Hz), high- frequency (HF; 0.140-0.500 Hz) and total spectral powers (TF; 0.000-4.000 Hz) were calculated and the ratio of LF to HF and the percentage of HF relative to TF (%HF; HF/TF x 100) were used as indices of sympathovagal balance and parasympathetic activities, respectively. 3. In the present study, QTc dispersion failed to correlate with LF/HF and %HF. Systolic blood pressure and pulse rate increased significantly during tooth extraction; however, changes in these variables failed to correlate with QTc dispersion. 4. These results suggest that QTc dispersion is not associated with the power spectrum of R-R variability and that it does not affect the blood pressure response during tooth extraction.

Trends in the pathophysiological characteristics of malignant hypertension

The aim of the present study is to investigate the pathophysiological characteristics of a number of recent cases of malignant hypertension (MHT) and to compare them to the characteristics of earlier cases. Patients with MHT (age 25-76, mean 44+/-2 years) who were admitted to our hospital from 1984-1999 were retrospectively studied. All of the patients had either grade III or IV retinopathy and diastolic blood pressure levels higher than 120 mmHg. The observations in this study were compared to previously reported findings regarding 59 MHT patients who were admitted from 1971-1983. Of the 37 recent MHT patients, 20 had essential hypertension (EHT) as the underlying disease, 13 had chronic glomerulonephritis (CGN), and the remaining 4 presented with other diseases including pyelonephritis and renovascular hypertension. A positive family history of hypertension was more prevalent in the EHT patients than in other patients, and persistent proteinuria, microhematuria, and anemia were more prevalent in the CGN patients. These characteristics were similar between the recent and previous cases. Within 4 weeks after admission, hemodialysis was initiated in 3 of the 13 patients (23%) with CGN and 2 of the 20 (10%) patients with EHT. The prevalence of renal death at 1 year after admission was 30%, which was lower than the prevalence in the previous cases (42%). Grade IV retinopathy was seen in 45% of the patients admitted from 1984-1999, significantly less than in the patients admitted from 1971-1983 (66%, p<0.05). In addition, left ventricular hypertrophy was less frequently observed on electrocardiogram in the recent cases (67%) than in the previous cases (88%, p<0.05). Our results suggest that the recent cases of MHT demonstrate less severe organ damage.

Ellagitannins and hexahydroxydiphenoyl esters as inhibitors of vertebrate squalene epoxidase

Ellagitannins isolated from various plant sources as well as newly synthesized n-alkyl (C(1)-C(18)) esters of hexahydroxydiphenyl (HHDP) dicarboxylic acid were evaluated as enzyme inhibitors of recombinant rat squalene epoxidase, a rate-limiting enzyme of cholesterol biosynthesis. Among the ellagitannins tested, pedunculagin (IC(50) = 2.0 microM) and eugeniin (IC(50) = 1.6 microM), both containing (S)-HHDP ester group(s), showed remarkable inhibition, which was more potent than those of previously reported substrate analogue inhibitors. Furthermore, ellagic acid (IC(50) = 2.0 microM), a bislactone formed by hydrolytic release of a HHDP group from ellagitannins, was also a good inhibitor of the enzyme. On the other hand, the synthetic HHDP esters with C(6) (IC(50) = 0.93 microM) and C(8) alkyl side chains (IC(50) = 0.83 microM) showed potent enzyme inhibition at the submicromolar concentration range, while esters with shorter chain lengths (C(1)-C(4)) and a C(18) ester exhibited moderate inhibition (IC(50) = 8-47 microM).

Transcranial doppler sonography and ambulatory blood pressure monitoring in patients with hypertension

To appraise the value of transcranial Doppler sonography (TCD) for assessment of hypertensive cerebrovascular damage, the relationship between ambulatory blood pressure (BP) and indices of cerebral circulation determined by TCD was investigated. Subjects were 55 inpatients with or without hypertension, including 13 patients with histories of cerebrovascular attacks. Mean flow velocity (MFV) in the middle cerebral artery was measured by TCD, then the cerebrovascular resistance index (CVRI; mean BP/MFV) and the Fourier PI1 (pulsatility index of the first Fourier harmonic of the flow-velocity waveform) were determined as indices of cerebrovascular resistance. CO2 reactivity of MFV was estimated as an index of cerebrovascular flow reserve. CVRI positively correlated with both daytime and nighttime BP as well as with age (p<0.01). Fourier PI1 positively correlated with nighttime BP and age (p<0.01). CO2 reactivity did not correlate with any of the ambulatory BP parameters, but negatively correlated with age (p<0.01). LV mass index significantly correlated with ambulatory BP parameters, CVRI, and Fourier PI1 but did not correlate with CO2 reactivity. Multiple regression analyses showed that nighttime systolic BP was a significant correlate for CVRI and Fourier PI1, but not for CO2 reactivity, and that history of cerebrovascular attack was significant for CVRI and CO2 reactivity. We conclude that cerebrovascular resistance determined by TCD accords with the results of ambulatory BP and LVMI, and thus could be successfully used to detect the early stage of hypertensive cerebrovascular change. Cerebrovascular flow reserve would be relatively preserved in hypertensive patients without cerebrovascular diseases.

Novel polyketides synthesized with a higher plant stilbene synthase

The physiological function of the stilbene synthase (STS) from groundnut (Arachis hypogaea) is the formation of resveratrol. The enzyme uses 4-coumaroyl-CoA, performs three condensations with malonyl-CoA, and folds the resulting tetraketide into a new aromatic ring system. We investigated the capacity for building novel and unusual polyketides from alternative substrates. Three types of products were obtained: (a) complete reaction (stilbene-type), (b) three condensations without formation of an aromatic ring (CTAL-type pyrone derailment), and (c) two condensations (BNY-type pyrone derailment). All product types were obtained from 4-fluorocinnamoyl-CoA and analogs in which the coumaroyl moiety was replaced by furan or thiophene. Only type (b) and (c) products were synthesized from other 4-substituted 4-coumaroyl-CoA analogs (-Cl, -Br, -OCH3). Benzoyl-CoA, phenylacetyl-CoA, and medium chain aliphatic CoA esters were poor substrates, and the majority of the products were of type (c). The results show that minor modifications can be used to direct the enzyme reaction to form a variety of different and new products. Manipulation of the biosynthesis of polyketides by synthetic analogs could lead to the development of a chemical library of pharmaceutically interesting novel polyketides.

Comparative actions of insulin sensitizers on ion channels in vascular smooth muscle

Thiazolidinedione and isoxazolidinedione insulin sensitizers activate peroxisome proliferator-activated receptor gamma (PPAR gamma). Some thiazolidinediones modify ion channels in smooth muscles; however, the mechanism by which their actions occur has not been clarified. We, thus, examined the effects of three thiazolidinediones (troglitazone, pioglitazone, and rosiglitazone) and isoxazolidinedione (JTT-501), as well as an intrinsic ligand for PPAR gamma, 15-deoxy-Delta(12,14) prostaglandin J(2) (prostaglandin J(2)), on voltage-operated Ca(2+) currents (I(Ca)), voltage-dependent K(+) currents (I(Kv)), and Ca(2+)-activated K(+) currents (I(Kca)), to clarify whether a thiazolidinedione structure or PPAR gamma activation is related to their actions on ion channels. The whole-cell patch clamp method was used to record currents in smooth muscle cells from guinea-pig mesenteric arteries. Thiazolidinediones inhibited I(Ca) in a dose-dependent manner (troglitazone>pioglitazone=rosiglitazone). Troglitazone (> or =1 microM) and rosiglitazone (100 microM), but not pioglitazone, inhibited I(Kv). Rosiglitazone (> or =10 microM) enhanced, troglitazone (> or =1 microM) inhibited, and pioglitazone did not affect I(Kca). A high concentration of JTT-501 (100 microM) inhibited I(Ca), I(Kv), and I(Kca) to a similar extent. Prostaglandin J(2) enhanced I(Kca), but affected neither I(Ca) nor I(Kv). In summary, the three thiazolidinediones and isoxazolidinedione act differently on Ca(2+) and K(+) channels in vascular smooth muscle. The action of thiazolidinediones on I(Ca) could be attributed to specific regions of the molecules and not to activation of PPAR gamma. Involvement of PPAR gamma activation in the stimulation of I(Kca) is possible but should be tested further.

Benzalacetone synthase. A novel polyketide synthase that plays a crucial role in the biosynthesis of phenylbutanones in Rheum palmatum

Benzalacetone synthase (BSA) is a novel plant-specific polyketide synthase that catalyzes a one step decarboxylative condensation of 4-coumaroyl-CoA with malonyl-CoA to produce the C6-C4 skeleton of phenylbutanoids in higher plants. A cDNA encoding BAS was for the first time cloned and sequenced from rhubarb (Rheum palmatum), a medicinal plant rich in phenylbutanoids including pharmaceutically important phenylbutanone glucoside, lindleyin. The cDNA encoded a 42-kDa protein that shares 60-75% amino-acid sequence identity with other members of the CHS-superfamily enzymes. Interestingly, R. palmatum BAS lacks the active-site Phe215 residue (numbering in CHS) which has been proposed to help orient substrates and intermediates during the sequential condensation of 4-coumaroyl-CoA with malonyl-CoA in CHS. On the other hand, the catalytic cysteine-histidine dyad (Cys164-His303) in CHS is well conserved in BAS. A recombinant enzyme expressed in Escherichia coli efficiently afforded benzalacetone as a single product from 4-coumaroyl-CoA and malonyl-CoA. Further, in contrast with CHS that showed broad substrate specificity toward aliphatic CoA esters, BAS did not accept hexanoyl-CoA, isobutyryl-CoA, isovaleryl-CoA, and acetyl-CoA as a substrate. Finally, besides the phenylbutanones in rhubarb, BAS has been proposed to play a crucial role for the construction of the C6-C4 moiety of a variety of natural products such as medicinally important gingerols in ginger plant.

Central orexin-A augments sympathoadrenal outflow in conscious rabbits

We determined the cardiovascular and neurohormonal responses to intracerebroventricular administration of orexin-A in conscious rabbits. Intracerebroventricular injection of orexin-A elicited dose-related increases in mean arterial pressure and renal sympathetic nerve activity. Peak values of mean arterial pressure and renal sympathetic nerve activity induced by intracerebroventricular injection of 100 pmol of orexin-A (14.0+/-0.7 mm Hg and 55.4+/-14.9%, respectively) were obtained at 40 and 25 minutes after injection, respectively. Plasma epinephrine and glucose concentrations were significantly increased at 60 and 90 minutes after intracerebroventricular injection of orexin-A (control versus 90 minutes; for epinephrine, 38.0+/-12.8 versus 167.5+/-42.5 pg/mL, P<0.01; for glucose, 6.66+/-0.18 versus 7.75+/-0.14 mmol/L, P<0.01). Plasma norepinephrine and insulin concentrations increased at 60 and 90 minutes but did not attain significant values. Intracerebroventricular injection of orexin-A also caused significant increases in plasma vasopressin concentrations. However, pretreatment with an intravenous injection of pentolinium (5 mg/kg), a ganglion-blocking agent, abolished these cardiovascular and neurohormonal responses. On the other hand, intravenous injection of the same dose of orexin-A (100 pmol) used in the intracerebroventricular experiment failed to cause any cardiovascular and renal sympathetic nerve responses. These results suggest that intracerebroventricular orexin-A acts in the central nervous system and activates sympathoadrenal outflow, resulting in increases in arterial pressure and plasma glucose levels in conscious rabbits.

MYOCARDIAL IMAGING WITH123I-METAIODOBENZYLGUANIDINE IN ESSENTIAL HYPERTENSION AND RENOVASCULAR HYPERTENSION

Iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging is considered to reflect cardiac sympathetic function. We performed myocardial MIBG scintigraphy and echocardiography in 27 patients with essential hypertension (EHT), 7 patients with renovascular hypertension (RVHT), and 8 normotensive subjects (NT) to investigate alterations in MIBG myocardial imaging in the presence of hypertension and left ventricular hypertrophy (LVH). EHT were divided into two groups based on LV wall thickness; EHT with LVH group (> or = 13 mm, n = 15) and EHT without LVH group (< 13 mm, n = 12). The delayed uptake of MIBG was decreased, and the washout rate of MIBG was greater in the EHT with LVH group than EHT without LVH group or NT group. The washout rate was correlated with LV mass and LV diastolic function (as assessed by mitral flow). In RVHT group, the MIBG washout rate increased even without LVH, compared with NT and EHT without LVH groups. In summary, the washout rate of MIBG increased in parallel with the development of LVH in EHT and increased independently of the LV mass in RVHT. Cardiac sympathetic function could be altered in hypertensive LVH and in renovascular hypertension.

Cardiovascular and sympathetic responses to dental surgery with local anesthesia

We investigated changes in blood pressure and blood variables, including plasma catecholamines, serum glucose and insulin concentrations, during dental surgery. The study included 11 normotensive patients (age, 22.5+/-0.7 years) who underwent tooth extraction at Kyushu Dental College Hospital. Three to 7 days prior to dental surgery, blood pressure, pulse rate, and heart rate variability were measured every 30 min over 24 h. The low frequency (LF: 0.05 to 0.15 Hz) and high frequency (HF: 0.15 to 0.40 Hz) powers were calculated, and the ratio of LF to HF (LF/HF) and HF were used as indexes of sympathetic and parasympathetic activities, respectively. Lidocaine, 2% with epinephrine (1:80,000), was used as the local anesthetic for all patients. Systolic blood pressures significantly increased during dental surgery (+10.8+/-3.5 mmHg); however, this increase failed to correlate not only with baseline systolic blood pressure but with 24-h averaged blood pressures, LF/HF or HF. On the other hand, plasma epinephrine and norepinephrine concentrations increased during dental surgery, and peak values of these variables were obtained after local anesthesia and during tooth extraction, respectively. Serum glucose level increased after local anesthesia (control vs. local anesthesia: 5.16+/-0.11 vs. 5.62+/-0.10 mmol/l; p<0.01); however, plasma insulin concentrations did not change significantly. These results suggest that 1) ambulatory measurements of blood pressure and heart rate variability over 24 h cannot predict the responses of blood pressure during dental surgery, and that 2) administration of local anesthetic and tooth extraction activate sympathoadrenal outflow, resulting in an increase in serum glucose level in normotensive subjects.

The influence of chronic antihypertensive treatment on the central pressor response in SHR

We examined the influence of chronic antihypertensive treatment on the central pressor response in SHR. Adult male SHR were divided into 5 groups, i.e., those receiving 1) enalapril (Enal: 25 mg/kg/day in drinking water, n=12); 2) losartan (Los: 40 mg/kg/day, n=11); 3) candesartan (Cand: 4 mg/kg/day, n=12); 4) hydralazine+hydrochlorothiazide (H&H: 50+7.5 mg/kg/day, n=9); 5) vehicle (

CONTROL

n=9). At 4 weeks of treatment, hypertonic saline (0.25, 0.5 M) was intracerebroventricularly (i.c.v.) injected into conscious rats. Plasma catecholamines were measured before and after i.c.v. injection. On completion of the experiment, heart weight was measured, and angiotensin-converting enzyme (ACE) activity of the cerebrum was determined. All antihypertensive drugs elicited comparable reductions in systolic blood pressure, while heart rate was significantly higher in the H&H group than in the other groups during treatment. Pressor response to i.c.v. hypertonic saline (0.5 M) was significantly smaller in the Enal (12 +/- 3 mmHg) and Cand (11 +/- 2 mmHg) groups than in the Los (22 +/- 2 mmHg), H&H (16 +/- 2 mmHg), and CONTROL (29 +/- 5 mmHg) groups. Plasma catecholamines did not differ among the groups. Heart weight was lowest in the Enal group, followed by the Los and Cand groups. ACE activity of the cerebrum was significantly decreased in the Enal group. The results suggest that chronic treatment with various antihypertensive drugs differentially alters the central pressor response in SHR, and enalapril and candesartan are effective in attenuating this response.

Sustained hemostatic abnormality in patients with steroid-induced osteonecrosis in the early period after high-dose corticosteroid therapy

To determine whether the development of steroid-induced osteonecrosis in collagen disease patients was related to hemostatic abnormality after corticosteroid administration, we examined levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha2-plasmin inhibitor complex (PIC) in 32 patients who were treated with high-dose corticosteroid. All were prospectively followed for osteonecrosis, with serial magnetic resonance imaging (MRI), for at least 12 months from the beginning of corticosteroid therapy. MRI was performed on bilateral hips and knees. Of the 32 patients, 17 (53.1%) had osteonecrosis in the hip or knee. Osteonecrosis was detected on MRI at an average 3.1 months after the start of high-dose corticosteroid therapy. PIC levels were significantly higher in the group of 17 patients with osteonecrosis (ON group) than in the group of 15 patients without osteonecrosis (non-ON group) (P < 0.0001). The difference in PIC levels was most prominent 20 days after the start of the high-dose corticosteroid therapy. Moreover, the number of osteonecrotic joints was significantly correlated with PIC levels (P < 0.0001). The sustained hemostatic abnormality after corticosteroid therapy in the ON group suggests that microvascular coagulation participates in the development of osteonecrosis.

Green tea polyphenols as potent enhancers of glucocorticoid-induced mouse mammary tumor virus gene expression

The effect of natural and synthetic galloyl esters on glucocorticoid-induced gene expression was evaluated by using rat fibroblast 3Y1 cells stably transfected with a luciferase reporter gene under the transcriptional regulation of the mouse mammary tumor virus promoter. The glucocorticoid-induced gene transcription was strongly suppressed by synthetic alkyl esters; n-dodecyl gallate showed the most potent inhibition (66% inhibition at 10 microM), which was far more potent than that of crude tannic acid. n-Octyl and n-cetyl gallate also showed good inhibition, while gallic acid itself was not so active, suggesting that the presence of hydrophobic side chain is important for the suppressive effect. On the other hand, surprisingly, green tea gallocatechins, (-)-epigallocatechin-3-O-gallate and theasinensin A, potently enhanced the promoter activity (182 and 247% activity at 1 microM, respectively). The regulation of the level of the glucocorticoid-induced gene expression by the antioxidative gallates is of great interest from a therapeutic point of view.

Impaired beta-adrenergic hyperpolarization in arteries from prehypertensive spontaneously hypertensive rats

Stimulation of beta-adrenoceptors leads to vascular smooth muscle hyperpolarization, presumably through the beta-adrenoceptors/Gs protein/adenylate cyclase/ATP-sensitive K(+)-channels (KATP) signaling cascade, which may play an important role in the sympathetic control of membrane potential. beta-Adrenoceptor-mediated hyperpolarization has been shown to be impaired in the established stage of experimental hypertension. The present study tested the hypothesis that beta-adrenergic hyperpolarization may be defective before the development of hypertension in some forms of genetic hypertension. We evaluated beta-adrenoceptor-mediated hyperpolarization using microelectrodes in mesenteric resistance arteries from 5-week-old, prehypertensive, spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). Isoproterenol-induced hyperpolarization was significantly smaller in SHR than in WKY (10(-7) mol/L: -4.6+/-0.6 versus -7.8+/-0.8 mV, P<0.01; 10(-6) mol/L -7.8+/-0.5 versus -9.8+/-0.6 mV, P<0.05; n=9). Furthermore, hyperpolarization to cholera toxin, a direct activator of Gs protein, was also impaired in SHR. On the other hand, hyperpolarization to forskolin, an adenylate cyclase activator, and to levcromakalim, a KATP opener, was comparable between groups. These findings suggest that beta-adrenoceptor-mediated hyperpolarization is defective in SHR before the development of hypertension, presumably because of an abnormality at the Gs protein site. Considering the importance of membrane potential in the control of vascular tone, altered beta-adrenergic control of membrane potential might play a role in the development of hypertension in SHR.

Enzymatic formation of unnatural aromatic polyketides by chalcone synthase

Substrate specificity of recombinant chalcone synthase (CHS) from Scutellaria baicalensis (Labiatae) was investigated using chemically synthesized aromatic and aliphatic CoA esters. It was demonstrated for the first time that CHS converted benzoyl-CoA to phlorobenzophenone (2,4,6-trihydroxybenzophenone) along with pyrone by-products. On the other hand, phenylacetyl-CoA was enzymatically converted to an unnatural aromatic polyketide, phlorobenzylketone (2, 4,6-trihydroxyphenylbenzylketone), whose structure was finally confirmed by chemical synthesis. Furthermore, in agreement with earlier reports, S. baicalensis CHS also accepted aliphatic CoA esters, isovaleryl-CoA and isobutyryl-CoA, to produce phloroacylphenones. In contrast, hexanoyl-CoA only afforded pyrone derivatives without formation of a new aromatic ring. It was noteworthy that both aromatic and aliphatic CoA esters were accepted in the active site of the enzyme as a starter substrate for the complex condensation reaction. The low substrate specificity of CHS thus provided further insight into the structure and function of the enzyme.

Central cardiovascular action of neuropeptide Y in conscious rabbits

We determined the central interactions of neuropeptide Y and leptin on cardiovascular and sympathetic responses in conscious rabbits. Intracerebroventricular injections of neuropeptide Y (0.1 and 1 nmol/40 microL) elicited dose-related decreases in arterial pressure and renal sympathetic nerve activity without a significant change in heart rate. Peak depressor or sympathoinhibitory responses of mean arterial pressure and renal sympathetic nerve activity (-13.0+/-1.5 mm Hg and -27.6+/-4.9%) were observed at 25 and 20 minutes after intracerebroventricular injection of 1 nmol of neuropeptide Y, respectively. Pretreatment with intracerebroventricular injection of leptin (3 nmol) prevented the depressor and sympathoinhibitory responses elicited by intracerebroventricular neuropeptide Y. Intravenous injection of the same dose of neuropeptide Y (1 nmol) as that used in the intracerebroventricular experiment failed to cause any cardiovascular and renal sympathetic nerve responses. On the other hand, a subdepressor dose of intracerebroventricular infusion of neuropeptide Y (1 nmol/300 microL per hour) significantly attenuated the baroreflex sensitivities assessed by renal sympathetic nerve activity and heart rate compared with vehicle infusion (G(max); -7.4+/-0.7 versus -13.7+/-0.9%/mm Hg, P:<0.01, and -4.0+/-0.3 versus -6.7+/-0.8 bpm/mm Hg, P:<0.05, respectively). These results suggest that central neuropeptide Y participates in the regulations of the sympathetic nerve activity to kidney and the baroreceptor reflex and that the depressor response induced by intracerebroventricular neuropeptide Y is modulated, at least in part, by central leptin in conscious rabbits.

Galloyl esters from rhubarb are potent inhibitors of squalene epoxidase, a key enzyme in cholesterol biosynthesis

Galloyl glucoses and galloyl proanthocyanidins obtained from rhubarb (Rhei Rhizoma, Rheum palmatum L., Polygonaceae); e.g. 1,2,6-tri-O-galloyl-beta-D-glucose (IC50 = 0.63 microM), 1,6-di-O-galloyl-2-O-cinnamoyl-beta-D-glucose (IC50 = 0.58 microM), procyanidin B-2 3,3'-di-O-gallate (IC50 = 0.54 microM), and procyanidin B-5 3,3'-di-O-gallate (IC50 = 0.55 microM), were found to be potent inhibitors of rat squalene epoxidase (SE). The inhibition at submicromolar level was far more potent than that of chemically synthesized substrate analogs. It was demonstrated for the first time that the cholesterol-lowering effect of rhubarb may be attributed to the potent inhibition activities of SE, a rate-limiting enzyme of cholesterol biogenesis.

Inhibition of vertebrate squalene epoxidase by isoprenyl gallates and phenylalkyl gallates

Galloy esters with 'substrate-like' isoprenoid or phenylalkyl side chains were newly synthesized and tested for the enzyme inhibition activities toward recombinant rat squalene epoxidase. Isoprenyl gallates (4-6) showed good inhibition (IC50 = 1.5 5.1 microM), as potent as previously reported substrate analogues, while phenylalkyl gallates (7-10) were moderate inhibitors of the enzyme (IC50 = 12-61 microM).

Voltage-dependent Ca2+ channels in resistance arteries from Dahl salt-sensitive rats

To determine whether chronic salt-loading would alter voltage-dependent Ca2+ channels in resistance arteries of Dahl salt-sensitive rats, whole-cell voltage-clamp experiments were performed on single cells that were isolated from small mesenteric arteries. Dahl salt-sensitive rats were fed either an 8% NaCl diet (high-NaCl group) or a 0.3% NaCl diet (low-NaCl group) from the age of 6 or 7 weeks. After 4 to 5 weeks, systolic blood pressure was significantly higher in the high-NaCl group than in the low-NaCl group. In the high-NaCl group, the threshold potential for Ca2+ channel current was more negative and the current amplitude that was normalized by cell capacitance was higher at negative command potentials (-40 mV to -20 mV), as compared with the low-NaCl group. When the current was separated into fast transient current and slow sustained (L-type) current, the alteration in the high-NaCl group was attributable to the change in L-type current. The steady-state inactivation curve was not different between the high-NaCl and low-NaCl groups. In conclusion, L-type Ca2+ channels in resistance arteries of Dahl salt-sensitive rats became more available for opening near the resting potential after dietary salt-loading.

Apoptosis-inducing activity of lipid derivatives of gallic acid

Gallic acid derivatives with a lipophilic group (hydrogenated farnesyl gallate, lauryl gallate, gallic acid laurylamide and cholesteryl gallate) were examined for their ability to induce apoptosis in human monoblastic leukemia U937 cells. Farnesyl ester derivative is the most potent apoptosis inducer among the compounds examined. The results suggest that lipid derivatives can augment the apoptosis-inducing activity of gallic acid depending on the structure. These findings will provide useful information in developing anti-cancer agents.

Antioxidative galloyl esters as enzyme inhibitors of p-hydroxybenzoate hydroxylase

Gallic acid and its esters were evaluated as enzyme inhibitors of recombinant p-hydroxybenzoate hydroxylase (PHBH), a NADPH-dependent flavin monooxygenase from Pseudomonas aeruginosa. n-Dodecyl gallate (DG) (IC(50)=16 microM) and (-)-epigallocatechin-3-O-gallate (EGCG) (IC(50)=16 microM), a major component of green tea polyphenols, showed the most potent inhibition, while product-like gallic acid did not inhibit the enzyme significantly (IC(50)>250 microM). Inhibition kinetics revealed that both DG and EGCG inhibited PHBH in a non-competitive manner (K(I)=18.1 and 14.0 microM, respectively). The enzyme inhibition was caused by specific binding of the antioxidative gallate to the enzyme, and by scavenging reactive oxygen species required for the monooxygenase reaction. Molecular modeling predicted that EGCG binds to the enzyme in the proximity of the FAD binding site via formation of three hydrogen bonds.

Angiotensin-converting enzyme inhibitor prevents age-related endothelial dysfunction

Vascular relaxation via endothelium-derived hyperpolarizing factor (EDHF) declines in association with aging and also with hypertension, and antihypertensive treatment improves the endothelial dysfunction connected with hypertension. We tested whether the angiotensin-converting enzyme inhibitor improves EDHF-mediated responses in normotensive rats, with special reference to the age-related process. Wistar-Kyoto rats (WKY) were treated with either 20 mg. kg(-1). d(-1) enalapril (WKY-E group) or a combination of 50 mg. kg(-1). d(-1) hydralazine and 7.5 mg. kg(-1). d(-1) hydrochlorothiazide (WKY-H group) from 9 to 12 months of age. Twelve-month-old WKY (WKY-O) and 3-month-old WKY (WKY-Y) served as controls (n=6 to 10 in each group). The 2 treatments lowered systolic blood pressure comparably. EDHF-mediated hyperpolarization to acetylcholine (ACh) in mesenteric arteries was significantly improved in WKY-E, but not in WKY-H, compared with WKY-O, and the hyperpolarization in WKY-E was comparable to that in WKY-Y (hyperpolarization to 10(-)(5) mol/L ACh in the presence of norepinephrine: WKY-O, -14+/-2 mV; WKY-E, -22+/-3 mV; WKY-H, -15+/-2 mV; and WKY-Y, -28+/-0 mV). EDHF-mediated relaxation, as assessed by relaxation to ACh in norepinephrine-precontracted rings in the presence of indomethacin and NO synthase inhibitor, was also significantly improved in WKY-E, but not in WKY-H, to a level comparable to that in WKY-Y (maximum relaxation: WKY-O, 45+/-6%; WKY-E, 63+/-8%; WKY-H, 43+/-4%; and WKY-Y, 72+/-4%). Hyperpolarization and relaxation to levcromakalim, an ATP-sensitive K(+) channel opener, were similar in all groups. These findings suggest that the angiotensin-converting enzyme inhibitor prevents the age-related decline in EDHF-mediated hyperpolarization and relaxation in normotensive rats, presumably through an inhibition of the renin-angiotensin system.

Renin-angiotensin system blockade improves endothelial dysfunction in hypertension

Angiotensin-converting enzyme (ACE) inhibitor improves the impaired hyperpolarization and relaxation to acetylcholine (ACh) via endothelium-derived hyperpolarizing factor (EDHF) in arteries of spontaneously hypertensive rats (SHR). We tested whether the angiotensin type 1 (AT(1)) receptor antagonist also improves EDHF-mediated responses and whether the combined AT(1) receptor blockade and ACE inhibition exert any additional effects. SHR were treated with either AT(1) receptor antagonist TCV-116 (5 mg. kg(-1). d(-1)) (SHR-T), enalapril (40 mg. kg(-1). d(-1)) (SHR-E), or their combination (SHR-T&E) from 8 to 11 months of age. Age-matched, untreated SHR (SHR-C) and Wistar Kyoto (WKY) rats served as controls (n=8 to 12 in each group). Three treatments lowered blood pressure comparably. EDHF-mediated hyperpolarization to ACh in mesenteric arteries in the absence or presence of norepinephrine was significantly improved in all treated SHR. In addition, the hyperpolarization in the presence of norepinephrine was significantly greater in SHR-T&E than in SHR-E (ACh 10(-5) mol/L with norepinephrine: SHR-C -7; SHR-T -19; SHR-E -15; SHR-T&E -22; WKY -14 mV). EDHF-mediated relaxation, assessed in the presence of indomethacin and N:(G)-nitro-L-arginine, was markedly improved in all treated SHR. Hyperpolarization and relaxation to levcromakalim, a direct opener of ATP-sensitive K(+)-channel, were similar in all groups. These findings suggest that AT(1) receptor antagonists are as effective as ACE inhibitors in improving EDHF-mediated responses in SHR. The beneficial effects of the combined AT(1) receptor blockade and ACE inhibition appears to be for the most part similar to those of each intervention.

Characteristics of Cyclodextrin Adsorption onto Activated Carbons

Whereas the amount of cyclodextrin (CD) adsorbed onto the large-pore activated carbon A (AC-A) increased with the number of glucose units, the amount adsorbed onto the small-pore activated carbon B (AC-B) showed the opposite tendency. This behavior can be accounted for in terms of a molecular exclusion. It is known that a good linear relationship is obtained between the Freundlich constants log K and 1/N for hydrophobic adsorption. The adsorption of CDs onto AC-A obeyed this relation, but, because of the molecular exclusion, the plots of AC-B deviated greatly. The adsorption of CDs onto AC-A was not explainable in terms of solubility. This could be because, in the case of a solid compound, adsorbability depends on the chemical potential of the molecule in aqueous solution whereas solubility depends also on the heat of fusion of the solid. In order to estimate the relative chemical potential of CDs in water, a method based on the numbers of carbon atoms and oxygen atoms in the molecule was devised which allowed a more accurate estimation of CD adsorbability than did solubility. The mean pore diameter of AC-A increased after CD adsorption, while that of AC-B showed little change. Copyright 2000 Academic Press.

Molecular anatomy of the peroxin Pex12p: ring finger domain is essential for Pex12p function and interacts with the peroxisome-targeting signal type 1-receptor Pex5p and a ring peroxin, Pex10p

The three peroxin genes, PEX12, PEX2, and PEX10, encode peroxisomal integral membrane proteins with RING finger at the C-terminal part and are responsible for human peroxisome biogenesis disorders. Mutation analysis in PEX12 of Chinese hamster ovary cell mutants revealed a homozygous nonsense mutation at residue Trp263Ter in ZP104 cells and a pair of heterozygous nonsense mutations, Trp170Ter and Trp114Ter, in ZP109. This result and domain mapping of Pex12p showed that RING finger is essential for peroxisome-restoring activity of Pex12p but not necessary for targeting to peroxisomes. The N-terminal region of Pex12p, including amino acid residues at positions 17-76, was required for localization to peroxisomes, while the sequence 17-76 was not sufficient for peroxisomal targeting. Peroxins interacting with RING finger of Pex2p, Pex10p, and Pex12p were investigated by yeast two-hybrid as well as in vitro binding assays. The RING finger of Pex12p bound to Pex10p and the PTS1-receptor Pex5p. Pex10p also interacted with Pex2p and Pex5p in vitro. Moreover, Pex12p was co-immunoprecipitated with Pex10p from CHO-K1 cells, where Pex5p was not associated with the Pex12p-Pex10p complex. This observation suggested that Pex5p does not bind to, or only transiently interacts with, Pex10p and Pex12p when Pex10p and Pex12p are in the oligomeric complex in peroxisome membranes. Hence, the RING finger peroxins are most likely to be involved in Pex5p-mediated matrix protein import into peroxisomes.

Removal and inactivation of hepatitis B virus from contaminated pooled plasma in a large-scale manufacturing process for factor VIII and human serum albumin

BACKGROUND AND OBJECTIVES

The Japanese Red Cross Society recalled one lot of monoclonal-antibody-purified factor VIII (F VIII) and two lots of human serum albumin (HSA) 5 months after preparation of the final products, because of a procedural error that led to contamination by a unit of plasma positive for hepatitis B surface antigen (HBsAg). We evaluated the effectiveness of virus inactivation/removal in a large-scale process for manufacturing F VIII and HSA.

MATERIALS AND METHODS

HBV DNA in the retained samples in process was measured by the polymerase chain reaction (PCR). The kinetics of virus inactivation by solvent-detergent (S/D) treatment was examined using model viruses. We also did a look-back survey of the patients who received corresponding products.

RESULTS

Contaminated hepatitis B virus (HBV) DNA became undetectable beyond fraction S IV-I in the albumin process and immunoaffinity chromatography in the F VIII process, respectively. The model viruses were inactivated within 5 s by S/D treatment. There is no evidence that patients were infected by HBV after transfusion of these products.

CONCLUSION

We conclude that virus inactivation/removal was effectively achieved in a large-scale manufacturing process for F VIII and HSA.

Acetabular labrum: abnormal findings at MR imaging in asymptomatic hips

PURPOSE

To determine the prevalence of abnormalities of the acetabular labrum in asymptomatic hips by means of magnetic resonance (MR) imaging and to correlate such abnormalities with age and the portion of the labrum.

MATERIALS AND METHODS

MR imaging was performed in 71 asymptomatic hips that were radially sectioned perpendicular to the acetabular labrum at 30 degrees intervals.

RESULTS

The shape of the labrum was triangular in 80% (304 of 382) of the labral segments, round in 13% (49 of 382), irregular in 7% (27 of 382), and not identified in 1% (two of 382). A homogeneous low signal intensity was observed in 56% (212 of 382). The frequencies of labral irregularity or its absence and of high signal intensity increased both with subject age and with a more anterior anatomic labral location.

CONCLUSION

In asymptomatic hips, abnormal findings regarding the shape and signal intensity of the acetabular labrum can be detected by means of MR imaging. The fact that the findings vary according to age and labral portion should be considered in interpreting MR images in patients suspected of having a labral lesion.