Ultrasound enhances retrovirus-mediated gene transfer.

Viral vector systems are efficient for transfection of foreign genes into many tissues. Especially, retrovirus based vectors integrate the transgene into the genome of the target cells, which can sustain long term expression. However, it has been demonstrated that the transduction efficiency using retrovirus is relatively lower than those of other viruses. Ultrasound was recently reported to increase gene expression using plasmid DNA, with or without, a delivery vehicle. However, there are no reports, which show an ultrasound effect to retrovirus-mediated gene transfer efficiency. Retrovirus-mediated gene transfer systems were used for transfection of 293T cells, bovine aortic endothelial cells (BAECs), rat aortic smooth muscle cells (RASMCs), and rat skeletal muscle myoblasts (L6 cells) with beta-galactosidase (beta-Gal) genes. Transduction efficiency and cell viability assay were performed on 293T cells that were exposed to varying durations (5 to 30 seconds) and power levels (1.0 watts/cm(2) to 4.0 watts/cm(2)) of ultrasound after being transduced by a retrovirus. Effects of ultrasound to the retrovirus itself was evaluated by transduction efficiency of 293T cells. After exposure to varying power levels of ultrasound to a retrovirus for 5 seconds, 293T cells were transduced by a retrovirus, and transduction efficiency was evaluated. Below 1.0 watts/cm(2) and 5 seconds exposure, ultrasound showed increased transduction efficiency and no cytotoxicity to 293T cells transduced by a retrovirus. Also, ultrasound showed no toxicity to the virus itself at the same condition. Exposure of 5 seconds at the power of 1.0 watts/cm(2) of an ultrasound resulted in significant increases in retrovirus-mediated gene expression in all four cell types tested in this experiment. Transduction efficiencies by ultrasound were enhanced 6.6-fold, 4.8-fold, 2.3-fold, and 3.2-fold in 293T cells, BAECs, RASMCs, and L6 cells, respectively. Furthermore, beta-Gal activities were also increased by the retrovirus with ultrasound exposure in these cells. Adjunctive ultrasound exposure was associated with enhanced retrovirus-mediated transgene expression in vitro. Ultrasound associated local gene therapy has potential for not only plasmid-DNA-, but also retrovirus-mediated gene transfer.

Effects of endothelium-derived hyperpolarizing factor and nitric oxide on endothelial function in femoral resistance arteries of spontaneously hypertensive rats.

In hypertension, endothelium-dependent relaxation is attenuated and this attenuation contributes to the increased peripheral resistance. However, the role of endothelium-derived hyperpolarizing factor (EDHF) in the arteries of hypertensive rats remains unclear. Therefore, the aim of this study was to evaluate the role of EDHF in the femoral resistance arteries of hypertensive rats. The femoral resistance arteries were isolated from 5-, 15- and 25-week-old spontaneously hypertensive rats (SHR) and age-matched Wistar Kyoto rats (WKY). Changes in internal diameter were examined with videomicroscopy. EDHF-mediated dilatation was determined by differences between the degree of acetylcholine (ACh)-induced dilatation in the presence of NG-monomethy-L-arginine (L-NMMA) plus a prostaglandin I2 inhibitor (indomethacin) and the degree of such dilatation in the presence of L-NMMA, indomethacin and KCl. Charybdotoxin (CTx) and apamin (a Ca2+-activated K+ channel [KCa] inhibitor)-sensitive EDHF dilatation was also compared between in 5-, 15- and 25-week-old SHR and WKY. ACh-induced vasodilatation was not different between 5-week-old SHR and WKY. There was no difference between NO- and EDHF-mediated vasodilatation in 5-week-old rats. ACh-induced vasodilatation was weaker in 15-week-old SHR than in WKY. NO-mediated vasodilatation did not differ between the two groups. EDHF-mediated dilatation was attenuated in SHR but not in WKY. ACh-induced dilatation was weaker in 25-week-old SHR than in WKY. NO- and EDHF-mediated vasodilatation were attenuated in SHR but not WKY. EDHF-mediated vasodilatation was attenuated before the loss of NO-mediated vasodilatation in the femoral resistance arteries of SHR. The attenuation of this vasodilatation was mediated by the CTx plus apamin-sensitive EDHF.

Enhanced release of endothelium-derived hyperpolarizing factor in small coronary arteries from rats with congestive heart failure.

1. Previous studies have suggested that the production of nitric oxide (NO) is reduced in coronary vessels of animals with congestive heart failure (CHF). However, the response to endothelium-derived hyperpolarizing factor (EDHF) in small coronary resistance arteries from CHF rats has not been investigated. The aim of the present study was to determine whether flow-induced dilation (FID) is altered in small coronary arteries from CHF rats and to characterize the role of EDHF in this process. 2. Small coronary arteries (97 +/- 6 microm) were isolated from control rats and from rats in which CHF was induced by left coronary artery ligation. The arteries were cannulated at 60 mmHg with flow. Changes in internal diameter were examined using videomicroscopy. 3. There was no significant difference in FID in small coronary arteries between control and CHF rats (68 +/- 6 vs 61 +/- 4% (expressed as a percentage of maximal dilation induced by nitroprusside (%MaxD(NP))), respectively). Flow-induced dilation in control rat vessels showed greater attenuation by N(G)-monomethyl-L-arginine (L-NMMA) than vessels from CHF rats (%NO-mediated FID 32 +/- 5 vs 16 +/- 3% (%MaxD(NP)), respectively). Pretreatment with indomethacin had no significant effect on FID in vessels from either rat group. Flow-induced dilation was attenuated by KCl (40 mmol/L) to a greater degree in vessels from CHF rats in the presence of L-NMMA and indomethacin compared with vessels from control rats (%EDHF-mediated FID: 36 +/- 4 vs 25 +/- 5% (%MaxD(NP)), respectively). Flow-induced dilation was abolished by removal of the endothelium and was significantly decreased in vessels from CHF rats in response to charybdotoxin plus apamin or tetrabutylammonium compared with control rat vessels. 17-Octadecynoic acid had no significant effect on FID in vessels from either control or CHF rats. 4. In conclusion, the FID of small coronary arteries is mediated by K+ channels, including the K(Ca) channels. Endothelium-derived hyperpolarizing factor-mediated dilation may compensate for the loss of NO-mediated dilation in CHF.

[Comparison of myocardial perfusion imaging by thallium-201 single-photon emission computed tomography with SUNY4001 (adenosine) and exercise--crossover clinical trial at multi-center].

We compared the ischemic diagnosis ability and adverse events of 201Tl myocardial perfusion imaging with SUNY4001 (adenosine) stress to that with exercise (ergometer) stress both on random crossover trial. Thirty one known or suspected chronic stable angina patients who are able to exercise and 10 healthy volunteers were enrolled for the trial. The early and delayed images were obtained by SPECT imaging. The concordance of diagnoses [ischemia vs. no ischemia] between the two types of stresses was 97.3% (36/37) [Kappa: 0.9068]. The sensitivity and specificity based on the exercise test were 100% (6/6) and 96.8% (30/31) respectively. The incidence of adverse events caused by SUNY4001 and the exercise were 44.7% (17/38) and 52.6% (20/38), respectively. Major adverse events caused by SUNY4001 were BP decrease, flushing and headache. And those by exercise were ST decrease, dyspnea and chest pain. None of the adverse events required the intervention or caused life-threatening complication in the trial. The trial showed that the ischemic diagnosis ability and safety of 201Tl scintigraphy with SUNY4001 stress are almost equal to those of the exercise stress that is considered as the standard stress method. We concluded that 201Tl imaging with SUNY4001 is safe and useful for detecting ischemic heart disease, especially for patients unable to exercise adequately.

The relationship between clinical stage, prognosis and myocardial damage in patients with Duchenne-type muscular dystrophy: five-year follow-up study.

UNLABELLED: The evaluation of myocardial damage by [123I] 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) imaging, which represents free fatty acid metabolism, has not been reported in patients with Duchenne-type muscular dystrophy (DMD). To date, the relationship between clinical stage, prognosis and myocardial damage has not been evaluated by radionuclear cardiac imaging. The main goal of this study was to elucidate the relationship of quantitative indices of myocardial damage obtained by radionuclear cardiac imaging ([201Tl] and [123I] BMIPP) to clinical stage and incidence of severe cardiac events in patients with Duchenne-type muscular dystrophy (DMD). METHODS: The study population consisted of 28 male patients with DMD. The average age at the beginning of observation was 19.1 +/- 7.4 yrs. Nuclear tomographic imaging was performed using [201Tl] and [123I] BMIPP. The mid-ventricular short axial slices were classified into four anatomical regions, and the normalized count data in these areas (TL, BM) were obtained. The endpoint was the occurrence of heart failure during the follow up period. RESULTS: Thirteen cases of heart failure occurred during the 5-year follow-up period, including three cases with cardiac death due to congestive heart failure. Clinical staging correlated directly with TL (p = 0.0118) and BM (p = 0.0401) in the whole left ventricle. In regional TL analysis, an association was observed only in the septum (p = 0.0151), and in the anterior (p = 0.0361) region. The only discrepancy between the tracer parameters (TL - BM) in the septum was observed with the radionuclear cardiac values, which exhibited a relationship with cardiac events (p = 0.0124). This discordance, TL < BM, was contrary to that usually observed in patients with ischemic heart disease. CONCLUSION: The septum is the critical area of significance for cardiac events and outcome in patients with DMD. The uptake of [201Tl] in this area was representative of the clinical stage, and TL-BM correlated well with the prognosis.

Candida parapsilosis endocarditis that emerged 2 years after abdominal surgery.

A 22-year-old man was hospitalized after 3 months of persistent fever and malaise. He had undergone abdominal surgery 24 months before admission. Echocardiography demonstrated two mobile pedunculated masses in the right ventricle. Multiple blood cultures were positive for Candida parapsilosis. After 4 weeks of miconazole treatment, the two masses were excised via a right atriotomy incision and the transtricuspid value approach. Histological examination revealed that they were fungal vegetation. Antifungal agents were continued for 1 year after surgery. The patient has remained well with no further symptoms for 3 years. This case suggests the necessity for careful evaluation of past history to avoid diagnostic delay in fungal endocarditis.

Cilnidipine as an agent to lower blood pressure without sympathetic nervous activation as demonstrated by iodine-123 metaiodobenzylguanidine imaging in rat hearts.

BACKGROUND: Administration of short-acting antihypertensive agents to patients with ischemic heart disease results in increased sympathetic nervous activity and is associated with worsened outcomes. Cilnidipine is an agent which blocks not only L-type calcium channels at the smooth muscle in the artery, but also N-type calcium channels at the presynaptic terminal. The goal of the present study was to determine the effect of cilnidipine on sympathetic nervous activity as on agent which blocks both L-type and N-type calcium channels at the presynaptic terminal, on sympathetic nervous activity in an experimental rat model using iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging. METHODS: Fourteen-week-old Wistar-Kyoto rats were divided into 3 separate groups: CTR group (control: distilled water administered), Nif group (nifedipine administered), or Cil group (cilnidipine administered). Agents were administered via a stomach tube, followed by injection of MIBG via the femoral vein. Systolic blood pressure (SBP) and heart rate (HR) were measured by tail-cuff plethysmography just prior to administration of antihypertensive drugs and 150 minutes later. Initial imaging (Ce) and delayed imaging (Cd) were defined as the sum of density counts in the region of interest created by adjusting to myocardial edge, and were corrected for both physical decay and weight. The myocardial washout rate (WR) was defined as the percent change in the count density from the initial to delayed images. RESULTS: Significant decreases in SBP were seen in the Nif group (from 132 +/- 3 mmHg to 85 +/- 5 mmHg, p < 0.0001) and the Cil group (from 128 +/- 4 mmHg to 92 +/- 7 mmHg, p = 0.0008), whereas no significant change in SBP was noted in the CTR group (from 123 +/- 5 mmHg to 127 +/- 3 mmHg). HR significantly increased in the Nif group (from 290 +/- 12/min to 378 +/- 14/min, p < 0.0001) but not in the CTR (from 278 +/- 3/min to 300 +/- 6/min) or Cil (from 291 +/- 6/min to 303 +/- 5/min) groups. WR was significantly greater in the Nif group (64.7 +/- 0.5%) when compared to the CTR (56.4 +/- 1.2%, p = 0.0031) or the Cil (55.4 +/- 2.2%, p = 0.0016) groups. CONCLUSION: In contrast to nifedipine, administration of cilnidipine did not result in increased myocardial sympathetic nervous activation.

Chronological changes of alpha-adrenoceptor-mediated vascular constriction in Otsuka-Long-Evans-Tokushima fatty rats.

In recent years, it has been suggested that many factors are involved in the development of hypertension accompanying insulin resistance. Because changes in vascular reactivity could be one of these factors, we here investigated chronological changes of alpha-adrenoceptor (AR)-mediated peripheral arteriolar vasoconstriction in a rat model of type II diabetes. Otsuka-Long-Evans-Tokushima fatty (OLETF) rats that naturally develop insulin resistance at the age of 16 weeks and type II diabetes at the age of 30 weeks (DM group) and control rats (N group) were used. Arterioles with a diameter of approximately 100 microm were removed from the cremaster muscle of 8-, 16- and 40-week-old rats and their diameters were measured in a tissue bath. The concentration-response curve (CRC) was determined for phenylephrine and UK14,304 both with and without N(G)-monomethyl-L-arginine (LNMMA). Although there were no significant differences in the CRC for phenylephrine between the 8-week-old DM group and N group, a leftward shift was seen for the 16- and 40-week-old DM groups. There were no significant differences in the CRC for UK14,304 between the two groups at any age, but in the presence of LNMMA, a leftward shift was seen in the 8- and 16-week-old but not in the 40-week-old DM groups. One possible explanation for these results is that impaired endothelium-dependent dilatation may have offset the reduction in arteriolar smooth muscle contraction. In conclusion, in the OLETF rats, the sensitivity of alpha-AR-mediated arteriolar vasoconstriction increased after the onset of insulin resistance. The sensitivity of alpha2-AR-mediated arteriolar smooth muscle contraction and endothelium-dependent vascular relaxation were both presumed to be impaired after the onset of type II diabetes.

Circadian gene expression of clock genes and plasminogen activator inhibitor-1 in heart and aorta of spontaneously hypertensive and Wistar-Kyoto rats.

OBJECTIVE: Heart and aorta possess biologic clocks, but their involvement in genetic hypertension has been unknown. Plasminogen activator inhibitor-1 (PAI-1) expression is directly regulated by clock genes, while angiotensin II modulates both PAI-1 and clock gene expression. We therefore examined circadian expression of PAI-1 and clock genes, and effects of angiotensin type 1 (AT1) receptor antagonism, in heart and aorta of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. METHODS: We examined cardiac and aortic mRNA expression for PAI-1 and clock genes (Per2, Bmal1, Clock, and Dbp) every 4 h throughout the day by quantitative reverse transcription-polymerase chain reaction, and intervention with the AT1 receptor antagonist candesartan and equihypotensive hydralazine. RESULTS: Cardiac PAI-1 expression was high in the dark, while aortic PAI-1 expression was high in the light. Both cardiac and aortic PAI-1 expression were greater in SHR than in WKY rats. Candesartan treatment decreased cardiac PAI-1 expression only in the dark in WKY rats but throughout the day in SHR. Candesartan but not hydralazine strongly attenuated circadian fluctuation of aortic PAI-1 mRNA in SHR and WKY rats. Clock genes oscillated synchronously in heart and aorta of SHR and WKY rats. Clock gene expression was increased in heart but not aorta of SHR. Candesartan did not affect clock gene expression. CONCLUSIONS: Enhanced expression of clock genes may increase PAI-1 expression in concert with activated renin-angiotensin system in SHR heart. Rather than clock genes, the renin-angiotensin system induces daily fluctuation and increased expression of aortic PAI-1 mRNA in SHR.

Wavelet transform analysis of heart rate variability to assess the autonomic changes associated with spontaneous coronary spasm of variant angina.

We used Wavelet transform (WT) to investigate whether variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina by analysis of heart rate variability (HRV). Twenty-one episodes preceding ST-segment elevation were selected under Holter monitoring in 12 men and 3 women with variant angina. HRV indices were calculated at 10 second intervals with the continuous WT, and analyzed within 30 minutes preceding ST-segment elevation. High frequency (HF; 0.15 approximately 2.00 Hz) increased significantly during the 4 minutes prior to ST-segment elevation, low frequency (LF; 0.04 approximately 0.15 Hz) decreased significantly during the period from 10 to 5 minutes and increased significantly during the 2 minutes prior to ST-segment elevation, the LF/HF ratio decreased significantly during the period from 10 to 3 minutes and increased significantly during the 2 minutes prior to ST-segment elevation. The RR interval decreased significantly during the 2 minutes prior to ST-segment elevation. These results suggest that the acute variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina. A reduction in sympathetic activity, then enhancement of vagal activity may play a key role in triggering the spontaneous coronary spasm, and the secondary activation of sympathetic activity may worsen the coronary spasm resulting in the attack.

The renin-angiotensin system is involved in the production of plasminogen activator inhibitor type 1 by cultured endothelial cells in response to chylomicron remnants.

Triglyceride-rich lipoproteins have been suggested to promote atherosclerosis. Plasminogen activator inhibitor type 1 (PAI-1) plays an important role in the events of cardiovascular pathophysiology. The renin-angiotensin system influences various vascular functions, including PAI-1 production. We examined whether or not chylomicron remnants increased PAI-1 mRNA and protein production in endothelial cells and whether or not an inhibition of the renin-angiotensin system interfered with this effect. Chylomicron remnants were isolated from functionally hepatectomized rats injected with chylomicrons. Human umbilical vein endothelial cell cultures (HUVECs) were incubated with chylomicron remnants with or without an angiotensin-converting enzyme inhibitor (temocaprilat), an angiotensin II receptor type 1 antagonist (RNH-6270), or an angiotensin II receptor type 2 antagonist (PD123319). Chylomicron remnants increased PAI-1 secretion in HUVECs (0.5 microg/ml; 128.3 +/- 6.1%, the mean +/- SEM) as well as angiotensin II (10 nmol/l; 130.7 +/- 9.5%) in 18 h, as compared with the controls, as well as stimulated PAI-1 mRNA expression to a maximum level at 4 h. Temocaprilat and RNH-6270, but not PD123319, attenuated all of these effects. Chylomicron remnants enhanced nuclear extract binding to a very low-density lipoprotein response element in the PAI-1 promoter region and activated nuclear factor-kappaB. Extracellular signal-regulated kinase (ERK 1/2) was phosphorylated in response to chylomicron remnants. These effects were inhibited by temocaprilat or RNH-6270. In conclusion, chylomicron remnants increased protein secretion and mRNA expression of PAI-1 in HUVECs. Inhibition of the renin-angiotensin system reduced this stimulation.

Troglitazone reduces activity of the Na+/H+ exchanger in fructose-fed borderline hypertensive rats.

Activation of the Na+/H+ exchanger (NHE) is known to be related to elevated blood pressure in hyperinsulinemia. We previously demonstrated that a fructose-enriched diet induced hyperinsulinemia and hypertriglyceridemia, elevated NHE activity, increased intracellular calcium concentrations ([Ca2+]i), and increased blood pressure in borderline hypertensive rats (BHR). This study examines whether pharmacologically reducing plasma triglyceride or insulin concentrations lowers blood pressure and reduces NHE activity in fructose-fed BHR. Eicosapentaenoic acid (EPA), bezafibrate (BEZ), and troglitazone (TRO) were administered to treat hypertriglyceridemia and/or hyperinsulinemia. Rats were fed a 60% fructose diet or a control diet for 4 weeks, followed by a diet with either vehicle, EPA, BEZ, or TRO for 4 weeks. Intracellular pH (pHi) was measured in platelets by fluorescent dye. Platelet NHE activity was evaluated by the recovery of pHi following addition of sodium propionate (Vmax). [Ca2+]i in platelets were measured fluorometrically. In fructose-fed rats, EPA prevented further increase in blood pressure, and reduced triglyceride concentration and [Ca2+]i without affecting Vmax or plasma insulin concentrations. BEZ reduced triglyceride concentrations without affecting blood pressure, Vmax, [Ca2+]i, or insulin concentrations. TRO prevented an increase in blood pressure, and reduced Vmax, [Ca2+]i, and insulin, but not triglycerides. Plasma insulin and Vmax were positively correlated. In conclusion, improvement of hyperinsulinemia can decrease NHE activity and blood pressure in fructose-fed BHR.

Impaired left ventricular function is associated with increased recovery time dispersion in patients with previous myocardial infarction.

Left ventricular (LV) dysfunction after myocardial infarction is associated with higher risk of serious ventricular arrhythmias and sudden death. We suspected that heterogeneity in ventricular repolarization contributes to these arrhythmias. To quantify this heterogeneity, we measured the recovery time (the interval between QRS onset and the time of maximum dV/dt in the ST-T segment) using an 87-lead body surface mapping electrocardiogram and estimated recovery time dispersion (the difference between maximum recovery time and minimum recovery time) in each lead. Differences between 110 patients with previous myocardial infarction and 31 healthy controls were compared. Recovery time dispersion [medians (25th, 75th percentiles)] was greatest in patients with a dilated LV [169 ms (154, 201) vs. 155 ms (137, 172), P <.005], impaired ejection fraction [173 ms (155, 202) vs. 152 ms (138, 165), P <.0005] and LV dyskinesis [175 ms (159, 201) vs. 155 ms (137, 161), P <.0005]. This study suggests that LV dysfunction associated with myocardial infarction leads to heterogeneous ventricular repolarization and may provide the electrical substrate for ventricular arrhythmias.

Augmented diurnal variations of the cardiac renin-angiotensin system in hypertensive rats.

There are several controversies concerning the enhanced gene expression of cardiac renin-angiotensin system components in spontaneously hypertensive rats (SHR) compared with their normotensive control Wistar-Kyoto (WKY) rats. We hypothesized that these discrepancies arise from circadian fluctuations in gene expression. We examined the circadian mRNA expression of renin, angiotensinogen, ACE, and angiotensin type 1a (AT1a) and type 2 (AT2) receptors in the hearts of SHR and WKY rats by real-time quantitative reverse transcription-polymerase chain reaction. The cardiac mRNA expression of the renin-angiotensin system components showed circadian oscillations in both SHR and WKY rats. The amplitudes of these circadian fluctuations were greater in the SHR than in the WKY rats. The mRNA levels of the renin-angiotensin system components were also increased in the SHR compared with the WKY rats at many time points (especially during the dark phase). However, the levels of ACE, AT1a receptor, and AT2 receptor mRNA in the SHR and WKY rats were almost the same during the late light phase. In contrast to mRNA expression, ACE activity was similar both at the time of maximum and minimum mRNA expression. The AT1 receptor antagonist candesartan upregulated AT1a receptor mRNA and downregulated ACE mRNA at specific time points only in the SHR group. Our findings of differential diurnal expression of cardiac renin-angiotensin system genes in SHR and WKY rats appear to explain the discrepancies between prior studies. However, the physiological relevance of the differential circadian mRNA expression of the renin-angiotensin system components remains to be elucidated.

Eicosapentaenoic acid improves endothelial function in hypertriglyceridemic subjects despite increased lipid oxidizability.

BACKGROUND: Epidemiologic investigations suggest that fish oil, which contains eicosapentaenoic acid (EPA), has favorable cardiovascular effects. Fish oil improves endothelial function in subjects with hypercholesterolemia or diabetes. However, controversy persists regarding relationships between primary hypertriglyceridemia and endothelial dysfunction. Moreover, lipoproteins are more susceptible to oxidation in vitro after incorporation of fish oil. METHODS: We determined the effects of EPA on serum lipids, susceptibility of low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) to oxidation, and endothelial function in hypertriglyceridemic (HTG) subjects. In 8 men with untreated primary hypertriglyceridemia (plasma triglyceride between 150 and 500 mg/dL) and 7 control subjects (triglyceride below 150 mg/dL), forearm blood flow (FBF) responses were tested. In HTG subjects, this was repeated 3 months after initiation of EPA (1800 mg/day). Cu2+-induced oxidation of VLDL and LDL was determined by serial measurement of conjugated dienes. We used lag time, which corresponded to the period when the lipoproteins were resistant to oxidation, as a parameter of oxidizability. FBF responses to acetylcholine and sodium nitroprusside were determined by strain-gauge plethysmography. RESULTS: Plasma triglyceride in HTG subjects fell 31% with EPA supplementation. Before EPA, VLDL and LDL lag times in HTG subjects were shorter than in control subjects. EPA further reduced lag time for VLDL but not LDL. The FBF response to acetylcholine (but not to nitroprusside) was significantly less in HTG subjects before EPA than in control subjects. EPA normalized the FBF response to acetylcholine. CONCLUSIONS: EPA improves endothelial function in HTG subjects despite increasing in VLDL oxidizability.

A decrease in the amount and function of the stimulatory GTP-binding protein in the small resistance arteries of spontaneously hypertensive rats.

We investigated the concentration of stimulatory GTP-binding protein (Gs protein) in the peripheral resistance arteries of spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY), and renovascular hypertensive rats (RHR). Changes in the function of Gs protein in SHR and WKY were also investigated by microcannulation techniques. The localization and abundance of Gs protein were determined immunohistochemically in 4-, 10- and 20-week-old SHR and age-matched WKY (control), as well as in RHR. Sections of the cremaster artery were stained with polyclonal antibodies to Gs protein. The concentration of Gs protein-like immunoreactivity in the cremaster artery was significantly lower in SHR at 4, 10, and 20 weeks of age, relative to that in age-matched WKY. In contrast, no significant differences were detected in the abundance of Gs between RHR and control rats. The dilatory response by isoproterenol in the presence of beta1-adrenoceptor blocker was lower in 4- and 10-week-old SHR than in age-matched WKY. The dilatory response by cholera toxin was also lower in SHR than in WKY for these two age groups. These results indicated that the amount and function of Gs protein in the peripheral resistance vessels in SHR was reduced. Since this change occurred before the onset of hypertension and no changes were seen in the secondary hypertensive rats, this change was not a secondary change due to hypertension. The impaired receptor-Gs protein-mediated signal transduction in the peripheral resistance arteries may be one of the possible mechanisms responsible for the pathogenesis of hypertension in SHR.

Correction of nonuniform attenuation and image fusion in SPECT imaging by means of separate X-ray CT.

Improvements in image quality and quantitation measurement, and the addition of detailed anatomical structures are important topics for single-photon emission tomography (SPECT). The goal of this study was to develop a practical system enabling both nonuniform attenuation correction and image fusion of SPECT images by means of high-performance X-ray computed tomography (CT). A SPECT system and a helical X-ray CT system were placed next to each other and linked with Ethernet. To avoid positional differences between the SPECT and X-ray CT studies, identical flat patient tables were used for both scans; body distortion was minimized with laser beams from the upper and lateral directions to detect the position of the skin surface. For the raw projection data of SPECT, a scatter correction was performed with the triple energy window method. Image fusion of the X-ray CT and SPECT images was performed automatically by auto-registration of fiducial markers attached to the skin surface. After registration of the X-ray CT and SPECT images, an X-ray CT-derived attenuation map was created with the calibration curve for 99mTc. The SPECT images were then reconstructed with scatter and attenuation correction by means of a maximum likelihood expectation maximization algorithm. This system was evaluated in torso and cylindlical phantoms and in 4 patients referred for myocardial SPECT imaging with Tc-99m tetrofosmin. In the torso phantom study, the SPECT and X-ray CT images overlapped exactly on the computer display. After scatter and attenuation correction, the artifactual activity reduction in the inferior wall of the myocardium improved. Conversely, the incresed activity around the torso surface and the lungs was reduced. In the abdomen, the liver activity, which was originally uniform, had recovered after scatter and attenuation correction processing. The clinical study also showed good overlapping of cardiac and skin surface outlines on the fused SPECT and X-ray CT images. The effectiveness of the scatter and attenuation correction process was similar to that observed in the phantom study. Because the total time required for computer processing was less than 10 minutes, this method of attenuation correction and image fusion for SPECT images is expected to become popular in clinical practice.

Hepatocyte growth factor as a potential predictor of the presence of atherosclerotic aorto-iliac artery disease.

BACKGROUND: Hepatocyte growth factor (HGF), a member of the endothelial-specific growth factors with the greatest mitogenic activity, may play a role in the protection and/or repair of vascular endothelial cells injured by atherosclerosis. As a result, plasma HGF concentration may increase in response to endothelial cell damage. To test this hypothesis, we measured plasma concentrations of HGF in patients with or without aorto-iliac artery atherosclerotic disease. METHODS: One hundred ten consecutive patients who underwent coronary angiography were enrolled in this study. Abdominal aortography was performed after coronary arteriography to determine whether aorto-iliac artery atherosclerotic disease was present. Peripheral venous blood samples were obtained to measure the plasma HGF concentration. RESULTS: Aortography revealed aorto-iliac atherosclerotic disease in 35 patients (32%). The plasma HGF concentration was significantly higher in patients with arteriosclerotic lesions (0.35 +/- 0.11 ng/mL) than in patients without atherosclerotic lesions (0.27 +/- 0.09 ng/mL, P =.0002). On the basis of multiple logistic regression analysis of the relationships between coronary risk factors, age, sex, severity of coronary artery disease, plasma HGF concentration, and the presence of arteriosclerotic lesions, plasma HGF concentration (P =.0005) and age (P =.035) were found to predict independently the presence of aorto-iliac arteriosclerosis. CONCLUSION: Plasma HGF concentration can be used to predict the presence of arteriosclerotic lesions in the region from the abdominal aorta to the femoral arteries.