The correlation between the clinical laboratory data and the telomere length in peripheral blood leukocytes of Japanese female patients with hypertension

OBJECTIVE

This study investigated the correlation between the chronological age, telomere length in peripheral blood leukocytes and blood laboratory data of female patients with mild hypertension to identify laboratory data that reflect the biological aging of individuals.

DESIGN

Cross-sectional population-based study.

SETTING

Outpatient clinic of the Department of Cardiovascular, Respiratory, and Geriatric Medicine Kyushu University Hospital at Beppu in Japan.

PARTICIPANTS

Outpatients with mild hypertension treated with a low dose of amlodipine.

MEASUREMENTS

The laboratory data of female patients were collected and the telomere length parameters in their peripheral blood leukocytes were determined by Southern blotting. Any correlations between the laboratory data and the telomere length parameters were assessed.

RESULTS

The patients showed a positive correlation between the telomere length and the high density lipoprotein, albumin, creatinine, hemoglobin levels, red blood cell counts, and a negative correlation with the globulin level. The extent of subtelomeric methylation of long telomeres tended to correlate negatively with the telomeric attrition. Only the creatinine level correlated with subtelomeric methylation, but not with telomeric length.

CONCLUSION

HDL and the albumin/globulin ratio were potential indicators for individual somatic genomic aging. Creatinine may therefore be a useful indicator for a predisposition for telomeric attrition.

The correlation between the telomeric parameters and the clinical laboratory data in the patients with brain infarct and metabolic disorders

OBJECTIVE

To elucidate the correlation between the telomere length and subtelomeric methylated status in peripheral leukocytes and the laboratory data of inpatients with brain infarction and metabolic disorders. This is the first report describing a link between routine clinical laboratory data and genomic aging.

DESIGN

Cross-sectional population-based study.

SETTING

Chronic disease ward of Kyushu University Hospital at Beppu in Japan.

PARTICIPANTS

Inpatients with brain infarction and metabolic disorders.

MEASUREMENTS

The laboratory data of male patients were collected and the telomeric parameters in their peripheral leukocytes were determined by a Southern blot analysis with methylation-sensitive and insensitive isoschizomers. Any correlations between the laboratory data and the telomeric parameters were assessed.

RESULTS

The patients revealed a significant correlation among the fasting blood sugar, HbA1c, serum creatinine and urea nitrogen levels with the mean telomere length, expression of long telomeres ( > 9.4 kb), or the subtelomeric hypermethylation status of long telomeres.

CONCLUSION

Our results suggested that the hyperglycemia and renal function of patients with metabolic disorders correlated positively with the aging-associated telomeric changes.

Induction of factor VIII-specific unresponsiveness by intrathymic factor VIII injection in murine hemophilia A

SUMMARY BACKGROUND

Hemophilia A is a congenital bleeding disorder caused by a deficiency of coagulation factor VIII. Approximately 30% of hemophilia A patients develop inhibitors against FVIII following replacement therapy. We have reported that neonatal exposure of FVIII antigen can induce antigen-specific immune tolerance by interferon-gamma (IFN-gamma)-dependent T-cell anergy in hemophilia A mice.

OBJECTIVE

The thymus plays crucial roles in self-tolerance, with negative selection of self-reactive effector T cells and positive selection of self-reactive regulatory T cells. We investigated the possibility of the induction of antigen-specific immune tolerance by intrathymic injection of FVIII in hemophilia A mice.

METHODS

Hemophilia A mice were injected with recombinant FVIII into the thymus under real-time high-resolution image guidance.

RESULTS

Anti-FVIII inhibitory antibody titers in mice challenged with intravenous administration of FVIII were significantly lower in mice (n = 22) that had received thymic FVIII injection than in mice (n = 18) without thymic injection (9.4 +/- 2.3 vs. 122.5 +/- 27.6 BU mL(-1), respectively, P = 0.00078). The CD4(+) T cells from thymic-injected mice could not proliferate or produce interleukin (IL)-2, IL-12 and IFN-gamma in response to FVIII. The CD4(+)CD25(+) T cells generated from thymic-treated mice but not from naïve mice efficiently suppressed the in vitro proliferative response of CD4(+) T cells and blocked the in vivo development of anti-FVIII antibodies in the adoptive transfer.

CONCLUSION

These data suggest that intrathymic administration of FVIII could result in immune tolerance by induction of FVIII-specific regulatory T cells.

Isolation and characterization of the human gene homologous to the Drosophila headcase (hdc) gene in chromosome bands 6q23-q24, a region of common deletion in human pancreatic cancer

Deletions of the long arm of chromosome 6 (6q) are one of the most common chromosomal abnormalities in multiple human malignancies. Previously, we have identified three commonly deleted regions on 6q (6q21, 6q23-q24, and 6q26) in pancreatic cancer by loss of heterozygosity studies, suggesting the presence of one or more tumor suppressor genes on this chromosome arm. Using a combination of database search and cDNA library screening, we successfully isolated a transcript from 6q24. This mRNA encodes a protein consisting of 543 amino acids with homology to the Drosophila headcase (hdc) gene and, thus, is designated as hHDC. Northern analysis identified a ubiquitously expressed 5.6-kb transcript. Seventeen (81%) of 21 pancreatic cancer cell lines and four (80%) of five renal cell carcinoma cell lines showed low level expression, suggesting that the hHDC gene may play an important role in some human cancers.

Restored vulnerability of cultured endothelial cells to high glucose by iron replenishment

High glucose (HG) concentrations are toxic to various cells in vivo, but cells become insensitive to HG toxicity when they are subcultured serially in vitro. Oxidative stress is involved in HG toxicity, and metal ions, especially iron, mediate some oxidative stress. To investigate mechanisms involved in the insensitiveness of cultured cells to HG toxicity, we focused on the level of intracellular iron. Freshly prepared human umbilical vein endothelial cells contained a substantial amount of iron, whereas its level decreased rapidly during the course of culture (to less than 10%). The iron content was restored by incubation of the cells with Fe(III)/8-hydroxyquinoline, and the iron-supplemented cells were more susceptible to both oxidant- and HG-induced injury. Under the HG conditions, the iron-loaded cells were subjected to higher levels of oxidative stress. The enhanced HG toxicity by iron was attenuated by the treatment with several antioxidants including catalase, ascorbic acid, and pyruvate. These data suggested that the insensitiveness of subcultured cells to HG toxicity is, at least in part, due to rapid and dramatic loss of intracellular iron. Supplementation with iron is useful to restore the vulnerability of cultured cells to HG that is normally observed in in vivo situations.

Intracellular mechanisms of cGMP-mediated regulation of myocardial contraction

The intracellular mechanisms of cGMP, a major intracellular mediator of nitric oxide that regulates the contractility of cardiac muscle, are still to some extent unknown. To investigate these mechanisms, we observed the effects of 8-bromo-cyclic GMP (8br-cGMP) on myofibrillar Ca2+ sensitivity and Ca2+ handling of the sarcoplasmic reticulum (SR) using beta-escin-skinned preparations from Wistar rat hearts. Both low (1 microM) and high doses (100 microM) of 8br-cGMP significantly decreased the myofibrillar Ca2+ sensitivity obtained from pCa-tension relationships to a similar extent (pCa50; from 6.04 to 5.95 by 1 microM 8br-cGMP and 6.00 to 5.89 by 100 microM 8br-cGMP, respectively, n = 9 each). Whereas this Ca2+ desensitization induced by 100 microM 8br-cGMP was blocked by 1 microM KT5823, a specific inhibitor of cGMP-dependent protein kinase (PKG), not induced by 1 microM 8br-cGMP was not effected by KT5823. When the amount of Ca2+ released from the SR was estimated by the peak amplitude of 25 mM caffeine-induced contractions after constant Ca2+-loading by pCa 6, both doses of 8br-cGMP significantly augmented the caffeine-induced peak force to a similar extent (125 +/- 5.8% by 1 microM 8br-cGMP and 116 +/- 5.1% by 100 microM 8br-cGMP, respectively, n = 6 each). The two observed effects of cGMP (a decrease in myofibrillar Ca2+ sensitivity and an increase in Ca2+ uptake by the SR) may participate in regulating myocardial contraction via nitric oxide. Low and high doses of cGMP seem to work mainly via PKG-independent and PKG-dependent pathways, respectively.

Effects of losartan on the collagen degradative enzymes in hypertrophic and congestive types of cardiomyopathic hamsters

The present study was undertaken to determine the effects of AT1 receptor blockade which occurred in response to losartan, on the extracellular matrix (ECM) degradation process in the Bio 14.6 (n = 12) and Bio 53.58 (n = 12) strains which are referred as models of hypertrophic and dilated cardiomyopathy, respectively. The administration of losartan (30 mg/kg/day) in hamsters from 10-20 weeks of age reduced the accumulation of the left ventricular collagen matrix in both of the Bio 14.6 and the Bio 53.58 strains. According to the RT-PCR, the levels of mRNA for matrix metalloproteinase (MMP) and the tissue inhibitor of MMP (TIMP) were examined. MMP-1, -2, -3, and -9 were more enhanced in both myopathic strains than in the control F1beta, strains. With losartan, the levels of MMP-1, -2, -9, TIMP-1 and -2 decreased in the both strains but those for MMP-3 did not in Bio 14.6 strains. TIMP-3 and -4 mRNA levels did not change in any of the experimental hamsters, whether treated or untreated with losartan. The Western blots also showed similar observations in the both strains as seen in mRNA expressions although MMP-2 in the Bio 53.58 strains did not differ between treated and untreated with losartan. Although losartan has an inhibitory effect on collagen accumulation in the development of cardiomyopathy, MMPs (-1, -2, -9) and TIMPs (-1, -2) seem to be susceptible to responding to losartan in Bio cardiomyopathic hamsters.

Alpha1-adrenoceptor-Gq-RhoA signaling is upregulated to increase myofibrillar Ca2+ sensitivity in failing hearts

Alpha1-adrenergic stimulation, coupled to Gq, has been shown to promote heart failure. However, the role of alpha1-adrenergic signaling in the regulation of myocardial contractility in failing myocardium is still poorly understood. To investigate this, we observed 1) the effect of phenylephrine on myofibrillar Ca2+ sensitivity in alpha-toxin-skinned cardiomyocytes, and 2) protein expression of Gq, RhoA, and myosin light chain phosphorylation using tachypacing-induced canine failing hearts. Phenylephrine significantly increased myofibrillar Ca2+ sensitivity in failing but not in normal cardiomyocytes. Whereas Y-27632 (Rho kinase inhibitor) blocked the phenylephrine-induced Ca2+ sensitization in the failing myocytes, calphostin C (protein kinase C inhibitor) had no effect on Ca2+ sensitization. The protein expression of Galpha(q) and RhoA and the phosphorylation level of regulatory myosin light chain significantly increased in the failing myocardium. Our results suggest that alpha1-adrenoceptor-Gq signaling is upregulated in the failing myocardium to increase the myofibrillar Ca2+ sensitivity mainly through the RhoA-Rho kinase pathway rather than through the protein kinase C pathway.

The down-regulation of glutathione peroxidase causes bovine luteal cell apoptosis during structural luteolysis

Prostaglandin (PG) F(2)a is known to initiate luteal cell apoptosis in the bovine corpus luteum (CL) via its specific receptor (FP) on the luteal membrane by inducing intracellular Ca(2+) mobilization and the activation of PKC. In order to identify the signaling components involved in cell apoptosis, mRNA levels and activities of antioxidative enzymes were analyzed using bovine CL at different stages of the estrous cycle. Northern blot analysis revealed that the levels of two isozymes of superoxide dismutase (SOD), the Mn and Cu/Zn types, and catalase are highly enriched in the middle estrous phase, whereas glutathione peroxidase (GPx) levels gradually decrease as the estrous cycle progresses. The incubation of bovine luteal cells with H(2)O(2) and mercaptosuccinate (MS), a specific inhibitor of GPx, resulted in an increase in chromatin DNA condensation and apoptotic DNA fragmentation. Analyses of the enzymatic activities of GPx and catalase support the RNA data, indicating that H(2)O(2) produced due to the lack of GPx is a potent inducer of luteal cell apoptosis.

Troglitazone, an antidiabetic drug, improves left ventricular mass and diastolic function in normotensive diabetic patients

AIMS

Patients with NIDDM have excessive cardiovascular morbidity and mortality, even in the absence of hypertension. Left ventricular hypertrophy (LVH), which is an ominous prognostic sign and an independent risk factor for cardiac events, is often present in NIDDM patients.

METHODS AND RESULTS

NIDDM male patients with (n=10) and without (n=12) hypertension, all of whom had been diagnosed over 10 years ago, were examined in the present study. Normotensive NIDDM patients had not received any anti-hypertensive drugs. All patients were classified according to the left ventricular mass (LVM) index by using M-mode echocardiography and were assessed regarding their systolic (fractional shortening) and diastolic function, which included the maximal early flow velocity (MFV), the mitral valve deceleration time (DT), and the isovolumic relaxation time (IRT) as determined by Doppler indices. Troglitazone (TRO), an antidiabetic drug, was administered to both groups at a dose of 400 mg/day for 6 months. After TRO treatment, a reduction in the LVM index and an improvement in the diastolic function were observed in the normotensive but not in the hypertensive patients.

CONCLUSION

The TRO treatment was sensitive for cardiac regression in those normotensive patients. These results suggest that LVH and the diastolic function in NIDDM patients without hypertension may be associated with elevated insulin resistance because TRO has a pharmacological function to increase the insulin sensitivity and to decrease insulin resistance.

Altered expression of heme oxygenase-1 in the livers of patients with portal hypertensive diseases

This study was designed to determine changes in expression of heme oxygenase (HO)-1, the stress-inducible and carbon monoxide-producing enzyme, in normotensive and portal hypertensive human livers. GTS-1, a monoclonal antibody against rat HO-1 cross-reacted with the human HO-1 and blocked its enzyme activity, allowing us to examine the activity and localization of HO-1. In controls, approximately 50% of the total HO activity was from HO-1 as judged by the sensitivity to GTS-1, while the rest of activity was from other isozymes such as HO-2. HO-1 was expressed mainly in a subpopulation of Kupffer cells, and the expression in hepatic stellate cells, sinusoidal endothelial cells, and hepatocytes was little, if any. The HO-1 expression exhibited quite different pictures in the livers of portal hypertensive diseases. In cirrhotic livers, which undergo portal hypertension through increases in intrasinusoidal resistance and regenerative changes in the parenchyma, HO-1 occurred in a majority of Kupffer cells and was also observed in hepatocytes. Consequently, the total HO-1 activities became significantly greater in these tissues than those from normal individuals. By contrast, livers of idiopathic portal hypertension that are characterized by an increase in presinusoidal resistance displayed a significant decrease in the HO-1 expression in Kupffer cells, and its hepatocellular expression was not detectable. Although factors involved in altered HO-1 expression in these cells remain unknown, the results suggest that Kupffer cells could alter their expression of HO-1 in response to local hemodynamic changes associated with chronic portal hypertension in humans.

Determination of left ventricular mass by echocardiography in normotensive diabetic patients

Patients with Type 2 diabetes mellitus (DM) have excessive cardiovascular morbidity and mortality, even in the absence of hypertension. Left ventricular hypertrophy (LVH), which is an ominous prognostic sign and an independent risk factor for cardiac events, is often present in Type 2 DM patients. Forty-two Type 2 DM patients without hypertension, all of whom had been diagnosed more than 10 years ago, were examined in the present study. They had no evidence of renal dysfunction and had not received any anti-hypertensive drugs. Age-matched healthy normal subjects (n=47) were recruited as controls. All participants were classified according to the left ventricular mass index (LVMI) using M-mode echocardiography and their systolic function (fractional shortening) was examined. The systolic function was not significantly different between the Type 2 DM and control groups. LVH can be seen even in the normotensive Type 2 DM patients, with these patients still having a higher LVMI than the normal control subjects. Although the plasma insulin levels were not significantly increased in the Type 2 DM patients, the LVMI significantly correlated with plasma insulin levels. However, the LVMI did not significantly correlate with plasma fasting glucose and hemoglobin A1c in the Type 2 DM patients. These results suggest that LVH in Type 2 DM patients without hypertension may be associated with elevated plasma insulin levels.

Does high-resolution MR imaging have better accuracy than standard MR imaging for evaluation of the triangular fibrocartilage complex?

We compared the findings of high-resolution MR imaging and standard MR imaging in the detection of tears of the triangular fibrocartilage in 33 patients with chronic wrist pain on the ulnar side. With arthroscopy as the standard of reference, sensitivity was 100%, specificity 53%, and accuracy 79% with the high-resolution MR imaging, against 83%, 67%, and 76% with the standard MR imaging. High-resolution MR imaging showed a higher sensitivity, but a decreased specificity in the assessment of the triangular fibrocartilage. The results showed that diagnosis of tears in the triangular fibrocartilage by MR imaging, even high-resolution MR imaging, is unsatisfactory, although further technological advances may well improve the accuracy.

Status of myocardial antioxidants in ischemia-reperfusion injury

BACKGROUND

Myocardial ischemia-reperfusion represents a clinically relevant problem associated with thrombolysis, angioplasty and coronary bypass surgery. Injury of myocardium due to ischemia-reperfusion includes cardiac contractile dysfunction, arrhythmias as well as irreversible myocyte damage. These changes are considered to be the consequence of imbalance between the formation of oxidants and the availability of endogenous antioxidants in the heart.

OBSERVATIONS

An increase in the formation of reactive oxygen species during ischemia-reperfusion and the adverse effects of oxyradicals on myocardium have now been well established by both direct and indirect measurements. Although several experimental studies as well as clinical trials have demonstrated the cardioprotective effects of antioxidants, some studies have failed to substantiate the results. Nonetheless, it is becoming evident that some of the endogenous antioxidants such as glutathione peroxidase, superoxide dismutase, and catalase act as a primary defense mechanism whereas the others including vitamin E may play a secondary role for attenuating the ischemia-reperfusion injury. The importance of various endogenous antioxidants in suppressing oxidative stress is evident from the depression in their activities and the inhibition of cardiac alterations which they produce during ischemia-reperfusion injury. The effects of an antioxidant thiol containing compound, N-acetylcysteine, and ischemic preconditioning were shown to be similar in preventing changes in the ischemic-reperfused hearts.

CONCLUSIONS

The available evidence support the role of oxidative stress in ischemia-reperfusion injury and emphasize the importance of antioxidant mechanisms in cardioprotection.

Interactions of nitric oxide and oxygen in cytotoxicity: proliferation and antioxidant enzyme activities of endothelial cells in culture

Nitric oxide (NO) shows cytotoxicity, and its reaction products with reactive oxygen species, such as peroxynitrite, are potentially more toxic. To examine the role of O2 in the NO toxicity, we have examined the proliferation of cultured human umbilical vein endothelial cells in the presence or absence of NO donor, ((Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-++ +ium-1,2-diolate) (DETA-NONOate) (100-500 microM), under normoxia (air), hypoxia (< 0.04% O2) or hyperoxia (88-94% O2). It was found that the dose dependency on NONOate was little affected by the ambient O2 concentration, showing no apparent synergism between the two treatments. We have also examined the effects of exogenous NO under normoxia and hyperoxia on the cellular activities of antioxidant enzymes involved in the H2O2 elimination, since many of them are known to be inhibited by NO or peroxynitrite in vitro. Under normoxia DETA-NONOate (500 microM) caused 25% decrease in catalase activity and 30% increases in glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities in 24h. Under hyperoxia NO caused about 25% decreases in activities of catalase, glutathione reductase and glucose-6-phosphate dehydrogenase. The H2O2 removal rate by NO-treated cells was computed on the mathematical model for the enzyme system. It was concluded that the cellular antioxidant function is little affected by NO under normoxia but that it is partially impaired when the cells are exposed to NO under hyperoxia.

High-density lipoproteins protect endothelial cells from tumor necrosis factor-alpha-induced apoptosis

High-density lipoproteins (HDL) levels have been shown to be inversely correlated with coronary heart disease, but the mechanisms of the direct protective effect of HDL on endothelial cells are not fully understood. The apoptosis of endothelial cells induced by cytokines and/or oxidized low-density lipoproteins, etc. may provide a mechanistic clue to the "response-to-injury" hypothesis of atherogenesis. Here we report that HDL prevent the apoptosis of human umbilical venous endothelial cells (HUVECs) induced by tumor necrosis factor-alpha (TNF-alpha) via an inhibition of CPP32-like protease activity. The incubation of HUVECs with TNF-alpha significantly increased the CPP32-like protease activity, and induced apoptosis. Preincubation of HUVECs with HDL before incubation with TNF-alpha significantly suppressed the increase in the CPP32-like protease activity, preventing apoptosis in a concentration-dependent manner. These results suggest that HDL prevent the suicide pathway leading to apoptosis of endothelial cells by decreasing the CPP32-like protease activity and that HDL thus play a protective role against the "response-to-injury" hypothesis of atherogenesis.

Reduction of plasma angiotensin II to normal levels by antisense oligodeoxynucleotides against liver angiotensinogen cannot completely attenuate vascular remodeling in spontaneously hypertensive rats

OBJECTIVE

The exact role of angiotensinogen (AGT) in vascular remodeling has yet to be determined. In the present study, we examined the effects of reducing plasma AGT by intravenous injections with antisense oligodeoxynucleotides (ODNs) against AGT targeted to the liver on vascular remodeling in spontaneously hypertensive rats (SHRs).

DESIGN AND METHODS

The ODNs against rat AGT were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method for regulating liver gene expression. Male SHRs (n = 18) and age-matched male Wistar- Kyoto (WKY) rats (n = 4) were used for this study. All animals were fed a standard rat diet throughout the experiment At 10 weeks of age, the SHRs were divided into three groups (n = 6); systolic blood pressure (SBP) was similar in each group. The control group received saline, the sense group was injected with the sense ODN complex and the antisense group was injected with the antisense ODN complex. WKY rats were fed for the same period of time. The ASOR-poly(L)lysine-ODN complex was injected into the tail veins twice a week.

RESULTS

At the end of the treatment, a reduction in AGT mRNA levels in the liver and plasma AGT was observed only in the animals injected with antisense ODNs. Antisense ODNs significantly reduced the plasma angiotensin II (Ang II) concentrations to levels similar to those observed in WKY rats. Antisense ODNs significantly reduced the SBP (180.7 +/- 4.4 mmHg) and media cross-sectional areas of the aorta (1.11 +/- 0.02 mm2), which were still larger than those seen in WKY rats (140.3 +/- 2.1 mmHg, 0.84 +/- 0.02 mm2), compared with the SHRs injected with sense ODNs (225.2 +/- 4.4 mmHg, 1.24 +/- 0.02 mm2) and control SHRs (223.7 +/- 4.8 mmHg, 1.25 +/- 0.02 mm2). The aortic angiotensin-converting enzyme (ACE) activity and collagen concentrations, which were significantly higher than those seen in WKY rats, did not significantly change among the SHR groups. The aortic AGT, ACE, angiotensin II type 1 (AT1) receptor and angiotensin II type 2 (AT2) receptor mRNA also did not significantly change among the SHR groups.

CONCLUSION

On the basis of these findings, plasma AGT is thus considered to play a role in the development of hypertrophy of smooth muscle in the aorta of SHRs, it is thought to have only a slight effect, however, on the remodeling of the matrix tissue when the suppression of hypertension is insufficient.

Pacing-induced palmar sweating evaluated by unique hygrometer: possible implications of sympathetic activation during tachycardia

Although reflex sympathetic activation is a major determinant of the haemodynamic tolerability of ventricular tachycardia (VT), the methods for evaluating this aspect during on-going VT remain invasive and complicated. Palmar sweating as an indirect but non-invasive measure of sympathetic activity was estimated by means of a unique hygrometer under right ventricular (RV) rapid pacing (up to 150 beats min-1) replicating VT, and concurrent monitoring of aortic blood pressure in five patients with various kinds of cardiac arrhythmias in our electrophysiological laboratory. The peak palmar sweating rate in arbitrary units was augmented as the RV pacing rate increased and was proportional to the pacing-induced fall in systolic blood pressure (SBP), with a correlation coefficient of more than 0.903 (P<0.006). The slope of linearity between the sweating rate and the fall in SBP varied among individual patients, with greater sweating amplitude in the younger patients even with the same extent of fall in SBP. This preliminary study suggests sympathetic acceleration caused by haemodynamic deterioration under simulated VT, and therefore this protocol may be able to predict the haemodynamic tolerability of sustained monomorphic VT.

Videotaped helical CT images for lung cancer screening

PURPOSE

The goal of this work was to determine a radiologist's ability to detect solitary pulmonary nodules on helical CT using both video (cine) viewing and film-based viewing.

METHOD

Sixty-five chest helical CT studies were reviewed. Six radiologists searched for 40 lung nodules on CT images presented in three formats. Film-based viewing of images at 10 and 5 mm increments was performed with a light box. Video viewing of the same examinations was performed in 5 mm increments at 2 frames/s. The area under the receiver operating characteristic curve (Az) measured the observer's ability to detect nodules.

RESULTS

The Az was 0.948 for the video viewing, 0.844 for 5 mm increment film-based viewing, and 0.879 for 10 mm increment film-based viewing. There were no statistically significant differences.

CONCLUSION

Lung nodules can be detected with similar detection rates when viewing conventional film or videotaped helical CT images. Videotaped images incur a lower cost, an important consideration in mass screening for lung cancer.

Low density lipoproteins develop resistance to oxidative modification due to inhibition of cholesteryl ester transfer protein by a monoclonal antibody

Although numerous studies have investigated the relationship between cholesteryl ester transfer protein (CETP) and high density lipoprotein (HDL) remodeling, the relationship between CETP and low density lipoproteins (LDL) is still not fully understood. In the present study, we examined the effect of the inhibition of CETP on both LDL oxidation and the uptake of the oxidized LDL, which were made from LDL under condition of CETP inhibition, by macrophages using a monoclonal antibody (mAb) to CETP in incubated plasma. The 6-h incubation of plasma derived from healthy, fasting human subjects led to the transfer of cholesteryl ester (CE) from HDL to VLDL and LDL, and of triglycerides (TG) from VLDL to HDL and LDL. These net mass transfers of neutral lipids among the lipoproteins were eliminated by the mAb. The incubation of plasma either with or without the mAb did not affect the phospholipid compositions in any lipoproteins. As a result, the LDL fractionated from the plasma incubated with the mAb contained significantly less CE and TG in comparison to the LDL fractionated from the plasma incubated without the mAb. The percentage of fatty acid composition of LDL did not differ among the unincubated plasma, the plasma incubated with the mAb, and that incubated without the mAb. When LDL were oxidized with CuSO4, the LDL fractionated from the plasma incubated with the mAb were significantly resistant to the oxidative modification determined by measuring the amount of TBARS and by continuously monitoring the formation of the conjugated dienes, in comparison to the LDL fractionated from the plasma incubated without the mAb. The accumulation of cholesteryl ester of oxidized LDL, which had been oxidized for 2 h with CuSO4, in J774.1 cells also decreased significantly in the LDL fractionated from the plasma incubated with mAb in comparison to the LDL fractionated from the plasma incubated without the mAb. These results indicate that CETP inhibition reduces the composition of CE and TG in LDL and makes the LDL resistant to oxidation. In addition, the uptake of the oxidized LDL, which was made from the LDL under condition of CETP inhibition, by macrophages also decreased.

Kupffer cell-independent acute hepatocellular oxidative stress and decreased bile formation in post-cold-ischemic rat liver

The purpose of this study was to examine distribution and time history of oxidative stress during the hyperacute period of reperfusion in the liver grafts undergoing cold ischemia and to investigate roles of Kupffer cells as a potential oxidant source. Rat livers were harvested at 4 degrees C in University of Wisconsin solution and followed by reperfusion with Krebs-Henseleit buffer under monitoring bile excretion. To investigate oxidative changes, laser-confocal microfluorography was performed in reperfused livers preloaded with dichlorodihydrofluorescein diacetate succinimidyl ester, a fluorescence precursor sensing intracellular hydroperoxide generation. Livers undergoing the 16-hour cold storage displayed an impaired recovery of bile acid-dependent bile output concurrent with a marked increase in hydroperoxide generation in hepatocytes, which occurred as early as 5 minutes after the onset of reperfusion, whereas the status of lobular perfusion was well maintained. Pretreatment with liposome-encapsulated dichloromethylene diphosphonate, a Kupffer cell-depleting reagent, did neither alter the reperfusion-induced periportal oxidative changes nor improve the recovery of bile output in the graft. On the other hand, EPCK, a hepatotropic antioxidant composed of vitamin E phosphate ester bound to vitamin C, not only diminished the oxidative changes but also improved the reduction of bile acid-dependent bile output. Furthermore, the reagent was capable of inhibiting H(2)O(2)-induced oxidative stress in cultured hepatocytes. These results suggest that hepatocytes constitute a major site of the oxidative insult triggered through Kupffer cell-independent mechanisms and serve as an important cellular component to be protected by antioxidant therapeutics.

Chronic antisense therapy for angiotensinogen on cardiac hypertrophy in spontaneously hypertensive rats

OBJECTIVE

We examined the effect of the suppression of plasma angiotensinogen (AGT) by the intravenous injection of antisense oligodeoxynucleotides (ODNs) against AGT targeted to the liver on cardiac remodeling in spontaneously hypertensive rats (SHR). The ODNs against rat AGT were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method for regulating liver gene expression.

METHODS

Male SHR (n = 18), and age-matched male Wistar-Kyoto rats (WKY, n = 6) were used for this study. At 10 weeks of age, the SHR were divided into three groups (each group n = 6), and the systolic blood pressure (SBP) did not significantly change among them. The control SHR and WKY groups received saline, the sense SHR group was injected with the sense ODNs complex and the antisense SHR group was injected with the antisense ODNs complex, from 10 to 20 weeks of age. ASOR-poly(L)lysine-ODNs complex was injected via the tail veins twice a week.

RESULTS

At the end of the treatment, a reduction of hepatic AGT mRNA, cardiac angiotensin II type 1 receptor mRNA and the plasma AGT concentration was only observed in the antisense-injected SHR but not in the other groups of SHR and WKY. This antisense therapy did not significantly change the mRNA expression for angiotensin converting enzyme, angiotensin II type 2 receptor and AGT in the left ventricle (LV) among all three groups. Although the plasma angiotensin II (Ang II) concentration significantly decreased to the level of WKY after the antisense therapy, the SBP, LV to body weight ratio and % collagen volume fraction also showed a reduction, however, these findings were still larger than in the WKY than in either the sense-injected SHR or control SHR.

CONCLUSION

The plasma AGT is considered to play a role in the development of cardiac hypertrophy in SHR, but it has not a complete effects on cardiac remodeling even if the plasma Ang II levels are inhibited because of an insufficient suppression of hypertension.

Cloning and characterization of the human UDP-N-acetylglucosamine: alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IV-homologue (hGnT-IV-H) gene

A novel human gene determining a polypeptide product of 478 residues with an estimated molecular mass of 55 kDa, which has significant homology and structural similarity to Bos UDP-N-acetylglucosamine: alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase (GnT-IV), was cloned from the commonly deleted region in pancreatic cancer at 12q21. The gene is composed of at least six exons, and the last three exons cover the open reading frame. Different sized transcripts, 3.8-kb in the heart, brain, and fetal brain and 2.8-kb and 1.7-kb in the testis were observed by Northern blot analysis. By reverse transcription-polymerase chain reaction, expression was also observed in the adult brain, liver, and adrenal gland, but not in pancreas. Because of its significant homology and structural similarity to Bos GnT-IV, it is potentially the gene encoding human GnT-IV or its homologue, which had been one of two genes remaining to be cloned in the human GnT family.

Induction of heme oxygenase-1 suppresses venular leukocyte adhesion elicited by oxidative stress: role of bilirubin generated by the enzyme

This study aimed to examine whether an elevated activity of heme oxygenase (HO)-1 in the tissue attenuates endothelial cell-leukocyte interactions microvessels in vivo. When rats were pretreated with an intraperitoneal injection of hemin, an HO-1 inducer, mesenteric tissues, including their microvessels, displayed a marked induction of HO-1 concurrent with an increase in plasma concentrations of bilirubin-IXalpha, the product of HO-catalyzed degradation of protoheme IX. In these rats, oxidative stress such as superfusion with H(2)O(2) and ischemia-reperfusion of the tissues neither induced rolling nor exhibited adherent responses of leukocytes in venules. In contrast, the oxidative stresses evoked marked rolling and adhesion of leukocytes in the control rats without HO-1 induction. The HO-1 induction also downregulated leukocyte adhesion elicited by other pro-oxidant stimuli such as N(omega)-nitro-L-arginine methyl ester. The decreases in the oxidant-elicited leukocyte adhesive responses under HO-1-inducing conditions were restored by perfusion with zinc protoporphyrin-IX, an HO inhibitor, but not with copper protoporphyrin-IX, which did not inhibit the enzyme. Furthermore, the effects of zinc protoporphyrin-IX were repressed by superfusion with bilirubin or biliverdin at the micromolar level, but not by the same concentration of carbon monoxide, another product of HO. These results indicate that induction of the HO-1 activity serves as a potential stratagem to prevent oxidant-induced microvascular leukocyte adhesion through the action of bilirubin, a product of HO reaction.

Secretion of prebeta HDL increases with the suppression of cholesteryl ester transfer protein in Hep G2 cells

Prebeta HDL are small, protein rich lipoproteins that are predominantly composed of apo A-I, without apo A-II. Prebeta HDL are secreted from the liver as nascent HDL and/or are produced in the incubated plasma by cholesteryl ester transfer protein (CETP). However, the role of CETP in the secretion of HDL from the liver has yet to be determined. In the present study, we examined the effect of the suppression of hepatic CETP by antisense oligodeoxynucleotides (ODNs) against CETP targeted to the liver on the secretion of apo A-I using a Hep G2 cell culture. The ODNs against CETP were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method for the regulation of liver gene expression. Hep G2 cells were cultured in DMEM supplemented with 10 FBS. After 2 days, the medium was changed to DMEM with EGF and the cells were divided into three groups. The control group received saline, while the sense group was mixed with the sense ODNs complex and the antisense group was mixed with the antisense ODNs complex, respectively, for 2 days. Both the hepatic CETP mRNA and the CETP mass in the medium in the antisense group decreased significantly more than in the sense and the control groups (CETP mass: 1.697 + /- 0.410 ng/mg cell protein vs. 2.367 + /- 0.22 and 2.360 + /- 0.139, n = 3 in each determination). In contrast, both the hepatic apo A-I mRNA and the apo A-I mass in the medium in the antisense group were significantly higher than those in the sense and the control groups (apo A-I mass; 1.877 + /- 0.215 micro/mg cell protein vs. 1.213 + /- 0.282 and 1.097 + /- 0.144, n = 3 in each determination). The increase in apo A-I was mainly due to the increase in prebeta apo A-I. These findings may partly explain why HDL and apo A-I increase in patients with CETP deficiency, while also indicating the possibility that the original level of prebeta HDL is sufficient in such patients.

Extracellular matrix regulation in the development of Syrian cardiomyopathic Bio 14.6 and Bio 53.58 hamsters

The myocardium contains a collagen matrix composed primarily of collagen and fibronectin, which are major determinants of the myocardial architecture, structural integrity and mechanical properties. The present study was undertaken to determine the age-related changes of the accumulation and degradation of the collagen matrix in Syrian myopathic hamsters, of the Bio 14.6 and Bio 53.58 strains. Those hamsters were used as models for hypertrophic and dilated cardiomyopathy, respectively. The heart to body weight ratio in the Bio 14.6 strains was higher (P<0.05) than that in the age-matched F1b strains. In the Bio 53.58 strains, the heart to body weight ratio was higher at 8 and 42 weeks of age than that in the F1b strains. The collagen content increased from 22 weeks of age in both Bio hamsters compared with age-matched F1b hamsters (P<0.05). In both cardiomyopathic hamsters, the mRNA expressions for type I and type III collagen and fibronectin all increased with aging; however, the fibronectin expression in the Bio 14.6 strains increased more at 22 weeks of age than at 42 weeks of age. The left ventricular MMP-1, MMP-2 and MMP-9 activities in Bio 53.58 strains increased with aging. However, in the Bio 14.6 strains, although MMP-1 activities increased with aging, MMP-2 and MMP-9 activities decreased at 42 weeks of age in comparison to those at 22 weeks of age. Thus, the MMP activation differed between two cardiomyopathic models at the stage of heart failure, although the collagen synthesis was elevated in both models. In conclusion, it would seem that the relative balance between the synthesis and the removal of collagen may contribute to the changes in the left ventricular geometry in two different types of cardiomyopathy.

Identification of three commonly deleted regions on chromosome arm 6q in human pancreatic cancer

Pancreatic cancer has one of the poorest prognoses among malignant diseases. To understand its molecular mechanisms, we studied allelic losses on the long arm of chromosome 6. Using 55 paired DNAs of tumors and their corresponding normal tissues and 30 microsatellite markers that spanned the entire 6q chromosome arm, we found three distinct regions of common allelic loss: region A, a less than 500-kb region bordered by D6S449 and D6S283 on 6q21 with a loss of heterozygosity (LOH) frequency of 69% (38/55); region B, a 7-cM region bordered by D6S292 and D6S308 on 6q23-q24 with a LOH frequency of 60% (33/55); and region C, a 13-cM region bordered by D6S305 and D6S264 with a LOH frequency of 51% (28/55). We further focused on region A and constructed a physical map using yeast artificial chromosome (YAC) clones, their derived cosmid clones, and bacterial artificial chromosome (BAC) clones. Region A was completely covered by three overlapping BAC clones. Our results in the present study should shed light on the cloning and characterization of tumor suppressor genes in pancreatic carcinogenesis.

Infrequent somatic mutations of the p73 gene in various human cancers

AIMS

It has already been reported that loss of heterozygosity (LOH) on chromosome 1p is frequent in a variety of human cancers. This finding implies the presence of some important tumour suppressor genes in this region. p73, a candidate tumour suppressor gene identified recently in chromosome band 1p36.33, encodes a protein highly homologous to p53. To investigate the role of the p73 gene in human carcinogenesis, we studied genetic alterations of this gene in various human cancers.

METHODS

We analysed the entire coding exons as well as their surrounding exon-intron boundaries of the p73 gene in 185 cases of various types of tumours (47 breast cancers, 43 colorectal cancers, 31 gastric cancers, 23 neuroblastomas, 21 lung cancer cell lines, and 20 pancreatic cancer cell lines); they are known as a group of tumours with frequent LOHs in the 1p region. PCR-SSCP analysis was performed and tumours in which aberrant migrating sized bands were observed were subjected to direct sequencing analyses.

RESULTS

Of the 185 cases, only one somatic mis-sense mutation of glutamine from arginine at codon 269 in exon 7 was found in one breast cancer. In addition, several polymorphisms were found at codons 137, 336, 349, and 610, as well as in introns 6, 8, and 9. Monoallelic expression was also observed in pancreatic cancer cell lines.

CONCLUSIONS

Our results suggest that inactivation of the p73 gene does not play a major role in the tumour types analysed in the present study.

Penetrating atherosclerotic ulcer at the proximal aorta complicated with cardiac tamponade and aortic valve regurgitation

A 56-year-old man had a penetrating atherosclerotic ulcer originating in the proximal ascending aorta, which is an unusual case of penetrating aortic ulcer complicated with the aortic valve regurgitation and cardiac tamponade. This hemodynamically unstable patient was successfully treated by conservative management to control his blood pressure and was also monitored closely with follow-up imaging studies.

Coexisting extraadrenal pheochromocytoma and von Meyenberg complexes: report of a case

We herein report on a 62-year-old man who developed extraadrenal pheochromocytoma and von Meyenberg complexes of the liver (bile duct microhamartoma). The patient identified preoperatively as having a paraaortic mass which was subsequently diagnosed to be a pheochromocytoma. During the operation, small multiple nodules were unexpectedly recognized in the liver. Some of the liver nodules were resected by a wedge biopsy, and then were pathologically identified to be von Meyenberg complexes. This may be the first reported case of the coexistence of pheochromocytoma and von Meyenberg complexes. It is therefore necessary for surgeons to be aware of von Meyenberg complexes in the differential diagnosis of multiple liver metastases in malignant disease.

Interaction of mRNAs for angiotensin II type 1 and type 2 receptors to vascular remodeling in spontaneously hypertensive rats

We administered angiotensin II (Ang II) receptor type 1 (AT1) blockade (losartan, 40 mg x kg-1 x d-1), type II receptor (AT2) blockade (PD123319, 100 mg x kg-1 x d-1), or angiotensin-converting enzyme (ACE) inhibitor (enalapril, 30 mg x kg-1 x d-1) to spontaneously hypertensive rats (SHR) from 10 to 20 weeks of age. Control SHR and Wister-Kyoto rats (WKY) received a placebo for the same period. At the end of treatment, losartan and enalapril were both found to have significantly reduced the arterial systolic blood pressure and the collagen concentration to the level of WKY, whereas PD123319 had no effect. Enalapril and PD123319 significantly reduced the media cross-sectional area of the aorta in comparison to that of untreated SHR, which was still larger than that of the WKY; however, losartan did not change it. Using reverse transcription-polymerase chain reaction, we next examined the mRNA expressions for ACE, AT1 receptor, and AT2 receptor in experimental animals. We observed significantly enhanced mRNA expression for AT1 and AT2 receptors and ACE in untreated SHR compared with WKY. The AT1 mRNA level was also significantly decreased in the SHR treated with either losartan or enalapril, whereas the AT2 mRNA level was significantly decreased in the SHR treated with either PD123319 or enalapril in comparison to untreated SHR. The level of ACE mRNA was significantly decreased only in the SHR treated with enalapril. These results indicate that AT1 receptor, but not AT2 receptor, plays a crucial role in the remodeling of matrix tissue, while AT2 receptor may play a role in the development of hypertrophy of smooth muscle in aorta in SHR, and that the reduction of hypertrophy of smooth muscle does not fully account for the suppression of hypertension.

Arthrography is superior to magnetic resonance imaging for diagnosing injuries of the triangular fibrocartilage

The ability of single-injection radiocarpal arthrography and magnetic resonance imaging (MRI) to detect full-thickness tears of the triangular fibrocartilage were compared with wrist arthroscopy in 102 patients with wrist pain. The sensitivity of arthrography was 85%, and of MRI was 73%. Specificity was 100% for arthrography and 72% for MRI. Accuracy was 92% for arthrography, and 73% for MRI. Although future advances in MRI technology will probably improve its usefulness, single-injection wrist arthrography currently is superior to routine MRI for the detection of full-thickness triangular fibrocartilage tears.

Effects of hepatic HDL-related mRNAs on plasma prebeta HDL in cholesterol-fed rabbits

This study was undertaken to determine; 1) the effect of cholesterol enriched diet on prebeta-migrating (prebeta) HDL levels, 2) the effect of the diet on plasma proteins and/or activities likely associated with prebeta HDL (cholesteryl transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT) and apolipoprotein (apo)A-I), 3) the effect of the diet on the corresponding hepatic mRNAs and 4) the correlation between the hepatic mRNAs and prebeta HDL. Rabbits were fed 0.1% (low) cholesterol (LC group, n = 6) or 0.5% (high) cholesterol diet (HC group, n = 6) for 6 weeks. Plasma CETP activities, plasma total apoA-I and prebeta apoA-I concentrations in the HC group were significantly increased (58.95 +/- 2.37%, 191.52 +/- 13.93 mg/dl, 44.21 +/- 1.14 mg/dl, respectively) compared with the LC group (39.36 +/- 3.62%, 152.85 +/- 8.61 mg/dl, 30.12 +/- 2.79 mg/dl, respectively)(p < 0.05). Plasma LCAT activities did not differ significantly (56.65 +/- 7.19 vs 57.41 +/- 8.21; HC vs LC). Hepatic CETP, LCAT and apoA-I mRNA levels were determined using reverse transcription polymerase chain reaction (RT-PCR). Hepatic CETP mRNA levels, compared to GAPDH mRNA levels as a control, were increased in the HC group (2.226 +/- 0.115) compared with the LC group (1.649 +/- 0.170) (p < 0.05), while hepatic LCAT and apoA-I mRNA levels were unchanged. Thus, plasma concentration of prebeta HDL, CETP activity and the amount of hepatic CETP mRNA were increased in response to the dietary intake of cholesterol. Multiple regression analyses showed that only hepatic CETP mRNA levels had a positive correlation with plasma prebeta HDL concentration (p = 0.04). These results indicate that individual variations in hepatic CETP mRNA levels in rabbits fed a cholesterol diet probably has a major influence on the determination of plasma prebeta HDL concentration.

Intravenous injection with antisense oligodeoxynucleotides against angiotensinogen decreases blood pressure in spontaneously hypertensive rats

In the renin-angiotensin system, renin is known to cleave angiotensinogen to generate angiotensin I, which is the precursor of angiotensin II. Angiotensin II is a vasoactive peptide that plays an important role in blood pressure. On the other hand, the liver is the major organ responsible for the production of angiotensinogen in spontaneously hypertensive rats (SHR). To test the hypothesis that a reduction of angiotensinogen mRNA in the liver by antisense oligodeoxynucleotides (ODNs) may affect both plasma angiotensinogen and angiotensin II levels, as well as blood pressure, we intravenously injected antisense ODNs against rat angiotensinogen coupled to asialoglycoprotein carrier molecules, which serve as an important regulator of liver gene expression, into SHR via the tail vein. The SHR used in the present study were studied at 20 weeks of age and were fed a standard diet throughout the experiment. Plasma angiotensinogen, angiotensin II concentrations, and blood pressure all decreased from the next day until up to 5 days after the injection of antisense ODNs. These concentrations thereafter returned to baseline by 7 days after injection. A reduction in the level of hepatic angiotensinogen mRNA was also observed from the day after injection until 5 days after injection with antisense ODNs. However, in the SHR injected with sense ODNs, plasma angiotensinogen, angiotensin II concentrations, and blood pressure, as well as hepatic angiotensinogen mRNA, did not significantly change throughout the experimental period. Although the exact role of angiotensinogen in hypertension still remains to be clarified, these findings showed that intravenous injection with antisense ODNs against angiotensinogen coupled to asialoglycoprotein carrier molecules targeted to the liver could thus inhibit plasma angiotensinogen levels and, as a result, induce a decrease in blood pressure in SHR.

Kinetics of hydrogen peroxide elimination by human umbilical vein endothelial cells in culture

H2O2 is a key substance in the oxidative stress. To evaluate the antioxidant activity of intact human umbilical vein endothelial cells (HUVEC), we measured the H2O2 removal rate by the cell in monolayer culture at various H2O2 concentrations (1-300 microM). It was shown that the removal reaction can be divided into two kinetically different reactions: reaction 1 apparently following the Michaelis-Menten kinetics and reaction 2 following the first-order kinetics. Reaction 1, which was diminished by treatment with diethyl maleate, could be attributed to GPx. Reaction 2, which was inhibited by aminotriazole, was principally attributable to catalase, though non-enzymatic reactions may contribute to it partially. Furthermore, we have constructed a mathematical model for the H2O2 elimination including the pentose phosphate pathway enzymes, GSSG reductase and GSH peroxidase. On the basis of the known kinetics and observed activities of the enzymes, the model could reproduce well the observed concentration dependence of the H2O2 removal rate. It was suggested from the simulation study that GSSG reductase is more important than G6PD in determining the rate of the NADPH-dependent H2O2 elimination.

Effect of antisense oligonucleotides against cholesteryl ester transfer protein on the development of atherosclerosis in cholesterol-fed rabbits

Cholesteryl ester transfer protein (CETP) is the enzyme that facilitates the transfer of cholesteryl ester from high density lipoprotein (HDL) to apolipoprotein B (apoB)-containing lipoproteins. However, the exact role of CETP in the development of atherosclerosis has not been determined. In the present study, we examined the effect of the suppression of increased plasma CETP by intravenous injection with antisense oligodeoxynucleotides (ODNs) against CETP targeted to the liver on the development of atherosclerosis in rabbits fed a cholesterol diet. The ODNs against rabbit CETP were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method to regulate liver gene expression. Twenty-two male Japanese White rabbits were used in the experiment. Eighteen animals were fed a standard rabbit chow supplemented with 0.3% cholesterol throughout the experiment for 16 weeks. At 8 weeks, they were divided into three groups (six animals in each group), among which the plasma total and HDL cholesterol concentrations did not significantly change. The control group received nothing, the sense group were injected with the sense ODNs complex, and the antisense group were injected with the antisense ODNs complex, respectively, for subsequent 8 weeks. ASOR. poly(L-lysine) ODNs complex were injected via the ear veins twice a week. Four animals were fed a standard rabbit diet for 16 weeks. The total cholesterol concentrations and the CETP mass in the animals injected with antisense ODNs were all significantly decreased in 12 and 16 weeks compared with those injected with sense ODNs and the control animals. The HDL cholesterol concentrations measured by the precipitation assay did not significantly change among the groups fed a cholesterol diet, and triglyceride concentrations did not significantly change in the four groups. However, at the end of the study, when the HDL cholesterol concentrations were measured after the isolation by ultracentrifugation and a column chromotography, they were significantly higher in the animals injected with antisense ODNs than in the animals injected with sense ODNs and in the control animals. A reduction of CETP mRNA and an increase of LDL receptor mRNA in the liver were observed in the animals injected with antisense ODNs compared with those injected with sense ODNs and the control animals. Aortic cholesterol contents and the aortic percentage lesion to total surface area were significantly lower in the animals injected with antisense ODNs than in the animals injected with sense ODNs and in the control animals. These findings showed for the first time that suppression of increased plasma CETP by the injection with antisense ODNs against CETP coupled to ASOR carrier molecules targeted to the liver could thus inhibit the atherosclerosis possibly by decreasing the plasma LDL + very low density lipoprotein (VLDL) cholesterol in cholesterol-fed rabbits.

Molecular mechanism of angiotensin II type I and type II receptors in cardiac hypertrophy of spontaneously hypertensive rats

We administered angiotensin (Ang) II receptor type 1 (AT1) blockade (losartan; 10 or 40 mg/kg per day), type II receptor (AT2) blockades (PD123319; 100 mg/kg per day), or angiotensin-converting enzyme (ACE) inhibitor (enalapril; 30 mg/kg per day) to spontaneously hypertensive rats (SHR) from 10 to 20 weeks of age. At the end of the treatment, high doses of losartan and enalapril significantly reduced the arterial systolic blood pressure compared with the untreated SHR to the level of WKY rats. But low doses of losartan and PD123319 were without effect. High doses of losartan and enalapril also significantly reduced both the left ventricular (LV) weight and the ratio of LV to body weight compared with the untreated SHR, which were still larger than that of WKY rats. However, the collagen concentration of SHR treated with high doses of losartan or enalapril was completely reduced to the level of WKY rats. Using reverse transcription polymerase chain reaction, we examined the mRNA expression for ACE, AT1, and AT2 in experimental animals. The enhanced AT1 mRNA expression was significantly decreased in the SHR treated with a high dose of losartan or PD123319 compared with the untreated SHR. The level of ACE mRNA was also decreased in the SHR treated with a high dose of losartan or enalapril. The level of AT2 mRNA was not significantly different between the Wistar-Kyoto rats and the SHR; however, this expression was decreased significantly after the treatment with a high dose of losartan or PD123319. These results indicate that AT1 receptor and ACE, but not AT2 receptor, play a crucial role in the remodeling of matrix tissue but a smaller role in the development of the hypertrophy of LV myocyte in SHR and that the LV/body weight changes do not fully account for the complete suppression of hypertension.

Effects of hypotonic stress on the survival of mouse oocytes and embryos at various stages

To examine the sensitivity of mammalian oocytes and embryos to osmotic swelling, which can occur during the removal of cryoprotectant from cryopreserved cells, the effect of hypotonic stress on the survival of fresh and vitrified mouse oocytes/embryos at various stages was examined. Oocytes and embryos were suspended in phosphate-buffered saline (PBS) media of various hypotonicities for 30 min at 25 degrees C. They were then returned to isotonic PBS medium, and the survival was assessed by the apparent integrity of the blastomeres and/or the developmental potential during culture. The survival of stressed embryos at one- to eight-cell stages assessed by the appearance was close to that assessed by the developmental ability, suggesting that hypotonic stress causes physical damage in the cell membrane. Fresh oocytes and embryos were almost totally unaffected by exposure to a 0.5x isotonic solution at all developmental stages examined. However, the extent of injury resulting from exposure to 0.3 to 0.2x isotonic solutions varied and depended on the developmental stage of the embryos. For example, zygotes were the least sensitive and morulae were the most sensitive to the hypotonic stresses. Except for morulae, vitrified cells were more sensitive to hypotonic stresses than were fresh ones. However, in many cases, the sensitivity was reduced or eliminated when the oocytes and embryos were cultured for a short period before exposure to the hypotonic stress. Furthermore, the survival rate of some stressed embryos which had been equilibrated in vitrification solution without cooling was higher than the survival of embryos stressed immediately following vitrification. These results show that sensitivity to osmotic swelling is variable among oocytes and embryos. The results also show that cryopreserved cells just after warming are more sensitive to osmotic swelling than are fresh ones, and even swelling corresponding to that in 0.5x solution may decrease survival in some stages.

Congenital intrahepatic arteriovenous fistulae in a young beagle dog

Congenital intrahepatic arteriovenous fistulae, a rare hepatic vascular anomaly, in an 8-mo-old female beagle dog was investigated. The animal showed anorexia, repeated vomiting, hemorrhagic diarrhea, and jaundice for approximately 2 wk. There was mild to severe increase of serum alkaline phosphatase, glutamic-oxalacetic transaminase, glutamic pyruvic transaminase, total cholesterol, total bilirubin, and gamma-glutamyl transpeptidase. Macroscopically, the main abdominal organs showed hemorrhagic edema together with bloody ascites. Other characteristic findings were severe hepatic atrophy (right medial, quadrate, left medial, and lateral lobes) with multiple vascular cysts and compensatory hypertrophy of the other lobes. The cystic vessels seemed to extend from the proper hepatic arteries and their branches but were indistinguishable from the portal vein. Histopathologically, the atrophied hepatic lobes were characterized by wide, fibrous septa containing severe hyperplasia and anastomosis of the arteriolae and venulae and proliferation of bile ducts.

Effect of dietary omega-3 eicosapentaenoic acid supplements on cholesteryl ester transfer from HDL in cholesterol-fed rabbits

We investigated the reactivities of cholesteryl ester transfer protein (CETP) in Japanese white rabbits fed either a low-cholesterol diet containing 0.1% cholesterol (Control group) or a diet containing 0.1% cholesterol plus 17.5% omega-3 eicosapentaenoic acid (omega-3 20:5, EPA) of 4.5% (w/w) total lipid (EPA group) for 6 weeks. The plasma total and LDL cholesterol levels and aortic cholesterol content were all significantly higher in the EPA group than in the control group. The aortic cholesterol content significantly correlated with LDL cholesterol (r = 0.81). HDL cholesterol levels tended to be lower in the EPA group compared with control group, which was not statistically significant. The plasma VLDL cholesterol levels did not differ significantly between the groups. In addition, no significant differences were observed in the plasma CETP activity or lecithin:cholesterol acyltransferase (LCAT) activity between the groups. However, the cholesteryl ester (CE) mass transfer from fractionated HDL in the EPA group to excess VLDL and/or LDL as acceptors by purified CETP increased significantly compared with the control group, even if the acceptors were fractionated from either the EPA or the control group. Fatty acid analyses of CE showed that the omega-3 18:3, 20:4 or omega-3 20:5 fatty acid acyl groups in CE of HDL were significantly more transferred to apo B-containing lipoproteins compared with the 14:0,16:0, 18:0, 18:1 or 18:2 fatty acid acyl groups in CE of HDL during the incubation period. The amount of CE in HDL containing omega-3 18:3 and omega-3 20:5 fatty acid acyl groups was greater, while the amount of CE containing 18:2 fatty acid acyl groups was smaller in the EPA group than in the control group. These results show that although CETP itself did not change, the transfer of CE in HDL to apo B-containing lipoproteins by CETP increased in the rabbits fed a diet containing EPA as the HDL is modified by the diet, which may partly explain why atherogenicity was thus found to progress in the rabbits fed a cholesterol plus EPA diet.

The effects of renin-angiotensin system inhibition on aortic cholesterol content in cholesterol-fed rabbits

To investigate how the renin-angiotensin system (RAS) might be involved in cholesterol-induced atherosclerosis, we studied the effects of a nonsulhydryl angiotensin converting enzyme (ACE) inhibitor, enalapril, and an angiotensin II receptor antagonist, E-4177, in cholesterol fed rabbits. Japanese white rabbits were randomly divided into four groups with the following dietary regimens: group A (n = 8) received a standard diet; group B (n = 8) had a 0.5% cholesterol diet; group C (n = 8) had a 0.5% cholesterol diet plus enalapril (10 mg/kg/day, p.o.); group D (n = 8) received a 0.5% cholesterol diet plus E-4177 (20 mg/kg/day, p.o.) and were fed these diets for 5 weeks. Enalapril or E-4177 had no significant effect on either the total plasma or the high density lipoprotein (HDL) cholesterol concentrations. However, the aortic cholesterol content in groups C and D was equally significantly less than that in group B. The plasma and aortic ACE activities were significantly reduced only in group C compared with those in the other groups. The aortic ACE mRNA and AT1 mRNA levels were assessed by a reverse transcription polymerase chain reaction (RT-PCR). The aortic ACE mRNA level was only significantly less in group C than in any of the other groups. The aortic AT1 mRNA level increased significantly in group B compared with that in group A and was significantly and equally reduced in both groups C and D compared with that in group B. These data indicate that angiotensin II rather than ACE may therefore be related to aortic cholesterol content. It follows therefore that the inhibition of angiotensin II by either ACE inhibitor or angiotensin II (type 1) receptor antagonist may play a role in prevention of atherosclerosis.

Ulnar impaction syndrome: MR imaging findings

PURPOSE

To evaluate magnetic resonance (MR) imaging findings in ulnar impaction syndrome and changes after ulnar recession arthroplasty.

MATERIALS AND METHODS

MR imaging and arthroscopy were performed in 30 wrists in 27 patients (aged 15-62 years) in whom ulnar impaction syndrome was diagnosed on the basis of physical examinations. MR imaging was performed in 11 wrists before and after surgery. T1- and T2-weighted spin-echo images were obtained. Signal intensities in the lunate, triquetrum, and ulnar head were evaluated.

RESULTS

There was focal abnormal signal intensity of the ulnar aspect of the lunate in 87% of wrists, of the radial aspects of the triquetrum in 43%, and of the radial aspects of the ulnar head in 10% before surgery. The signal intensity of the abnormalities was decreased on T1-weighted and decreased or increased on T2-weighted images. After surgery, the signal intensity of the lunate shifted from low through slightly low to normal on T1-weighted and from low through high to normal on T2-weighted images.

CONCLUSION

Most ulnar impaction syndrome cases have characteristic focal signal intensity changes in the ulnar part of the lunate. The signal intensity often returns to normal after ulnar recession arthroplasty.

Chronic low-dose treatment with enalapril induced cardiac regression of left ventricular hypertrophy

Numerous studies suggest that the renin angiotensin system (RAS) is involved in the development of cardiac hypertrophy. In the present study we produced cardiac hypertrophy in rats subjected to abdominal aortic banding and also induced cardiac regression by the administration of an angiotensin converting enzyme (ACE) inhibitor, enalapril, at 3, 10 and 30 mg/kg/day. Each drug was administered to the rats for 6 weeks from 6 weeks after aortic banding. The left ventricular weight significantly decreased at 10 and 30 mg/kg/day of enalapril as well as the systolic blood pressure. Using the reverse transcriptase polymerase chain reaction, the increased levels of ACE and AT1 mRNA were significantly inhibited in the aortic banding rats treated with the above concentrations of enalapril. The ACE activity in both the plasma and heart tissue preparations was significantly inhibited by enalapril. Similar observations were also seen after the administration of angiotensin type 1 receptor blockade, E-4177, into the aortic banding rats. The treatment with enalapril at 3 mg/kg/day did not reduce the left ventricular weight or the systolic blood pressure in the aortic banding rats. However, this low-dose treatment did significantly decrease the left ventricle to body weight ratio in the aortic banding rats without a reduction of the systolic blood pressure. Therefore, using the low-dose enalapril, the ACE activity in plasma was in part inhibited and the levels of ACE mRNA also decreased in the heart tissue of aortic banding rats, while the level of AT1 mRNA showed no such decrease. These results thus indicate that chronic ACE inhibitor at low doses has a beneficial effect on the regression in the pressure-induced cardiac hypertrophy. It is thus assumed that this effect may also contribute to the presence of an alternate pathway for the conversion of angiotensin I to angiotensin II which might also act as a possible mechanism for cardiac regression.

Changes in plasma lipoprotein cholesterol levels by antisense oligodeoxynucleotides against cholesteryl ester transfer protein in cholesterol-fed rabbits

Cholesteryl ester transfer protein (CETP) is the enzyme that facilitates the transfer of cholesteryl ester from high density lipoprotein (HDL) to apoB-containing lipoproteins and also affects the low density lipoprotein metabolism. On the other hand, the liver is the major tissue responsible for the production of CETP (CETP mRNA) in rabbits. To test the hypothesis that a reduction of CETP mRNA in the liver by antisense oligodeoxynucleotides (ODNs) may affect the plasma lipoprotein cholesterol levels, we intravenously injected antisense ODNs against rabbit CETP coupled with asialoglycoprotein carrier molecules, which serve as an important method to regulate liver gene expression, to cholesterol-fed rabbits via their ear veins. All rabbits were fed a standard rabbit chow supplement with 0.1% cholesterol for 10 weeks before and throughout the experiment. After injecting rabbits with antisense ODNs, the plasma total cholesterol concentrations and plasma CETP activities all decreased at 24, 48, and 96 h, whereas the plasma HDL cholesterol concentrations increased at 48 h. A reduction in the hepatic CETP mRNA was also observed at 6, 24, and 48 h after the injection with antisense ODNs. However, in the rabbits injected with sense ODNs, the plasma total and HDL cholesterol concentrations and the plasma CETP activities did not significantly change, and the hepatic CETP mRNA did not change either throughout the experimental period. Although the exact role of CETP in the development of atherosclerosis remains to be clarified, these findings showed for the first time that the intravenous injection with antisense ODNs against CETP coupled to asialoglycoprotein carrier molecules targeted to the liver could thus inhibit plasma CETP activity and, as a result, could induce a decrease in the plasma low density lipoprotein and very low density lipoprotein cholesterol and an increase in the plasma HDL cholesterol in cholesterol-fed rabbits.