Extension of hemorrhage after reperfusion of occluded coronary artery: contrast echocardiographic assessment in dogs

OBJECTIVES

The aim of this study was to elucidate the progression of intramural hemorrhage complicated by reperfusion with the use of myocardial contrast echocardiography.

BACKGROUND

Although hemorrhagic infarction is known to occur in ischemia followed by reperfusion, its onset and sequence have not been well characterized.

METHODS

In 20 anesthetized dogs, 3-h occlusion of the left circumflex-coronary artery was followed by reperfusion. The area at risk during coronary occlusion was approximately 25%. Myocardial contrast echocardiogram was examined, and the time-intensity curves for both ischemic and nonischemic areas were obtained at baseline, at 3 min after reperfusion and then at 15-min intervals until 90 min after reperfusion. The wall thickness of both areas was also measured.

RESULTS

Gross hemorrhage in the reperfused areas was observed in five dogs (Group H) but not in seven dogs (Group NH). All wall segments were opacified at 3 min after reperfusion in both groups. However, the contrast defect spread significantly with time after reperfusion in Group H but not in Group NH (18.7 +/- 3.4% and 3.3 +/- 1.8%, respectively, at 90 min after reperfusion p < 0.005). The wall of the risk area at 90 min after reperfusion had thickened to 1.3 times baseline thickness in Group H but was unchanged in Group NH. The other eight dogs were excluded from study because of fatal arrhythmias or the existence of collateral circulation during coronary occlusion.

CONCLUSIONS

Both progression of the contrast defect area on myocardial contrast echocardiography and a gradual thickening of the wall with reperfusion are characteristic of hemorrhagic infarction.

Choice of replacement valve in the elderly

BACKGROUND AND AIMS OF THE STUDY

Little comparative information exists on the outcome of the valve replacement with bioprostheses or mechanical valves in the elderly. This study was carried out to make such a comparison.

METHODS

Follow up data were examined from 219 patients aged > or = 65 years who underwent aortic and/or mitral valve replacement using bioprosthetic (n = 67) or mechanical valve (n = 152) between April 1979 and December 1993. The mean follow up periods were 6.3 +/- 2.8 years after bioprosthesis and 4.9 +/- 2.1 years after mechanical valve implantation.

RESULTS

Although the actuarial rate of structural deterioration was higher in patients with bioprosthetic valves than in those with mechanical valves (58% versus 100% freedom at 10 years after surgery, p < 0.01), no such prosthesis-related difference was seen in the subgroup of patients aged > or = 70 (100% versus 100% at nine years, p = N.S.). The actuarial rate of major bleeding was higher after mechanical valve implantation than after bioprosthetic valve placement (90% versus 100% freedom at 10 years, p < 0.05); this lower rate with bioprosthetic valves was maintained in patients aged > or = 70 (78% versus 100% at nine years, p < 0.05). There were no significant differences in the incidences of thromboembolism and bacterial endocarditis between the two valve types.

CONCLUSIONS

Structural degeneration of bioprosthetic devices was a major problem in patients aged 65-70 years, but it was essentially negligible in those aged > or = 70 years. Anticoagulant-related bleeding was a major problem with mechanical valves in both age groups. Therefore, for patients older than 70 years, valve replacement with a bioprosthesis appears to be the method of choice.

Intravascular ultrasonic evidence for importance of plaque distribution (eccentric vs circumferential) in determining distensibility of the left anterior descending artery

Although previous studies have shown that coronary atherosclerosis is accompanied by impaired vessel wall compliance, few data exist regarding the regional vessel distensibility that may be important in order to gain an insight into the mechanism of atherosclerotic plaque rupture. Therefore, we analyzed 45 coronary sites of the proximal left anterior descending artery from 40 patients. Using intravascular ultrasound, luminal area in diastole (A) and in systole was measured at the diseased sites. With the ratio of luminal area changes (dA) to coronary pressure changes (dP) during a cardiac cycle, the total distensibility index was obtained by the formula: [(dA/A)/dP] x 10(3). At the sites with noncircumferential disease perimeters in diastole (L) and in systole were measured at the normal and narrowed portions. Using the changes in perimeters (dL) during a cardiac cycle, the regional distensibility index was obtained by the formula: [(dL/L)/dP] x 10(3). In 22 sites with circumferential disease, the total distensibility index was 1.03 +/- 0.61/mm Hg (mean +/- SD), and significantly lower than that from 23 sites with noncircumferential disease that showed 1.45 +/- 0.89/mm Hg (p <0.05). In noncircumferential disease, the regional distensibility index at narrowed portions was significantly lower, 0.33 +/- 0.47/mm Hg, than that at normal portion, 1.11 +/- 0.75/mm Hg (p <0.01), suggesting the heterogenous distribution of regional wall distensibility in noncircumferential lesions. These results indicate that the heterogeneous regional wall distensibility exists at the sites with noncircumferential disease where the total vessel distensibility is preserved by the presence of the compliant normal portion.

Functional myocardial perfusion abnormality induced by left ventricular asynchronous contraction: experimental study using myocardial contrast echocardiography

OBJECTIVES

The aim of this study was to clarify how myocardial perfusion is impaired by asynchronous contraction.

BACKGROUND

False septal hypoperfusion is noted in some patients with left bundle branch block.

METHODS

Eight dogs were examined with epicardial pacing at the left ventricular posterior wall, the right ventricular anterior wall and, as a control, the right atrial appendage. The pacing rate was 80, 110 and 150 beats/min (bpm). Myocardial perfusion was assessed by contrast echocardiography.

RESULTS

Left ventricular pacing at 80 and 110 bpm did not change systolic wall thickening or contrast intensity at the pacing site, although an early excitation notch was noted at the pacing site. However, at 150 bpm, systolic thickening was impaired (23.3 +/- 4.2% vs. 37.0 +/- 2.6% during atrial pacing, p < 0.05), and the peak intensity ratio of the pacing site to the ventricular septum was significantly decreased (24.1 +/- 5.7% vs. 37.0 +/- 2.8% at a pacing rate of 80 bpm, p < 0.01). The peak intensity ratio correlated with systolic wall thickening at the pacing site (y = 0.413 x -0.028, r = 0.81, p < 0.0001). However, right ventricular pacing did not change either systolic thickening or the peak intensity ratio at any pacing rate, although an early excitation notch was noted on the ventricular septum.

CONCLUSIONS

Wall motion abnormalities after early excitation vary depending on the pacing mode. When tachycardia induces regional wall motion abnormalities, the ventricular wall of the pacing site is functionally hypoperfused.

Oscillation of ADP-ribosyl cyclase activity during the cell cycle and function of cyclic ADP-ribose in a unicellular organism, Euglena gracilis

In Euglena gracilis, the activity of ADP-ribosyl cyclase, which produces cyclic ADP-ribose, oscillated during the cell cycle in a synchronous culture induced by a light-dark cycle, and a marked increase in the activity was observed in the G2 phase. Similarly, the ADP-ribosyl cyclase activity rose extremely immediately before cell division started, when synchronous cell division was induced by adding cobalamin (which is an essential growth factor and participates in DNA synthesis in this organism) to its deficient culture. Further, cADPR in these cells showed a maximum level immediately before cell division started. A dose-dependent Ca2+ release was observed when microsomes were incubated with cADPR.

Usefulness of myocardial velocity gradient derived from two-dimensional tissue Doppler imaging as an indicator of regional myocardial contraction independent of translational motion assessed in atrial septal defect

Independence of myocardial velocity gradient from translational motion of the heart was tested by comparing normal subjects and patients with atrial septal defect. Myocardial velocity gradient obtained from patients fit within the normal range, even though the translation of the left ventricle was exaggerated in patients, demonstrating the translation independence of myocardial velocity gradient in clinical settings.

Attenuated inhibition of adrenergic contraction by nitric oxide in injured guinea pig femoral artery

The present study aimed to examine the altered modulation of adrenergic contraction by nitric oxide and sensory neuropeptides in balloon-injured muscular artery. A guinea pig femoral artery (GPFA) was injured by a newly developed silastic microballoon catheter. The contralateral GPFA served as the control. The studied GPFAs consisted of six groups; control (C) and injured (I) GPFA, isolated at 0 days, and 2 and 8 weeks after injury (C0, I0, C2, I2, C8, and I8). Isometric tension was measured in the presence of indomethacin (10(-5) M), to exclude effects of cyclooxygenase-generated eicosanoids. Endothelial removal with the catheter was confirmed by histological examination. In each group, except for 10, NG-nitro-I-arginine methyl ester (L-NAME, 10(-6) M) induced significant augmentation of perivascular nerve stimulation (PNS)-evoked adrenergic contraction, which was blocked by L-arginine (3 x 10(-4) M). The degree of L-NAME augmentation in I8 was significantly smaller than that in C8 and I2. Capsaicin (10(-6) M) did not significantly affect PNS-contraction in any group, indicating that there was no sensory neuropeptide involvement in this contraction. In I8, acetylcholine (10(-6) M)-induced relaxation after noradrenaline (10(-5) M)-precontraction was significantly smaller than that seen in the other groups, except for I0, which was lacking in acetylcholine-induced relaxation. Histologically, injured GPFAs showed progressive intimal thickening. The present findings thus showed attenuated nitric oxide-mediated inhibition of adrenergic contraction, accompanying intimal thickening, in balloon-injured muscular artery, 8 weeks after injury.

Prolonged myocardial contrast echocardiography via peripheral venous administration of QW3600 injection (EchoGen): its efficacy and side effects

We examined the efficacy and side effects of a newly developed contrast agent for intravenous myocardial contrast echocardiography, QW3600 Injection (EchoGen; Sonus Pharmaceuticals, Bothell, Wash.). Doses of 0.1, 0.2, 0.5, and 0.8 ml/kg of this agent were administered intravenously to 8 open-chested dogs. The left ventricular (LV) myocardium was uniformly well opacified for the 0.5 and 0.8 ml/kg doses, for which the peak intensity was an average of 40 gray levels above the baseline intensity. The myocardial opacification persisted even after the contrast echo intensity in the LV cavity had decreased. After ligation of the coronary artery, the area at risk was clearly delineated by the same doses. The agent emulsion and dissolved bubbles were examined microscopically in vitro and in vivo to elucidate the mechanism of prolonged opacification. A microscopic investigation of the mesenteric vessels of a rat indicated that bubbles had formed, growing as large as 30 to 50 microm [corrected] in diameter. The hemodynamic parameters did not change at low doses (0.1 and 0.2 ml/kg), but the systemic pressure fell and the arterial blood oxygen saturation decreased at high doses (0.5 and 0.8 ml/kg). EchoGen provides prolonged contrast for myocardial contrast echocardiography via peripheral venous administration, although the hemodynamic parameters deteriorate at high doses.

Mitochondrial NADH- or NADPH-linked aquacobalamin reductase activity is low in human skin fibroblasts with defects in synthesis of cobalamin coenzymes

Mammalian livers have been reported to contain NADH- and NADPH-linked aquacobalamin reductases, which are distributed in both mitochondria and microsomes. The four aquacobalamin reductase isozymes have been purified and characterized from rat liver. It is unclear which aquacobalamin reductase among the four reductase isozymes participates in the synthesis of cobalamin coenzymes. To clarify the physiological roles of the aquacobalamin reductase isozymes, human mutant fibroblasts (cblC and cblA cells) with defects in cobalamin reductases involved in the coenzyme synthesis were used. In the cblC cells, the activity of the mitochondrial NADH-linked aquacobalamin reductase was reduced significantly, compared with normal human fibroblasts but the mitochondrial NADPH-linked enzyme was not. The reduced specific activity of the NADH-linked enzyme was not due to reduction in levels of the enzyme, but in its affinity for NADH. Although there was not a significant difference in the mitochondrial NADH-linked enzyme activity between normal and cblA cells, the activity of the mitochondrial NADPH-linked enzyme was not detectable in the mutant cells. These results indicate that the defects in the mitochondrial NADH- and NADPH-linked aquacobalamin reductases underlie cblC and cblA disorders, respectively.

[Estimation of right ventricular contractility by continuous-wave Doppler echocardiography]

The right ventricular dP/dtmax and relatively load-independent index, dP/dtmax/IP (IP: instantaneous pressure difference between the right ventricle and right atrium) can be measured from the tricuspid regurgitant velocity by continuous-wave Doppler echocardiography. The present study investigated these indices as measures of right ventricular contractility. Thirty-one patients were classified into three groups: 11 patients without right ventricular disease (control group), 9 with dilated cardiomyopathy and 1 with hypertrophic cardiomyopathy in the dilated phase (DCM group), and 10 with pulmonary hypertension (PH group). Right ventricular contractility was impaired in both the PH group and DCM group, but dP/dtmax was significantly larger in the PH group compared with the control group and DCM group (519 +/- 113 vs 249 +/- 66 and 234 +/- 78 mmHg/sec, p < 0.01). There was no significant difference between dP/dtmax in the control group and DCM group. dP/dtmax/IP in the PH group was smaller than the control group (31 +/- 8 vs 39 +/- 7/sec, p < 0.05) and larger than the DCM group (22 +/- 12/sec, p < 0.05). Mean New York Heart Association grading was 1.0 in the control group, 3.1 in the DCM group, and 2.8 in the PH group, respectively. Thus, dP/dtmax/IP, noninvasively obtained by continuous-wave Doppler echocardiography, may be a better index for evaluating right ventricular contractility than dP/dtmax.

Mitral valve dysfunction resulting from thickening and stiffening of artificial mitral valve chordae

BACKGROUND

There is little information about changes in mitral valve function caused by thickening and stiffening of artificial chordae during follow-up. Using serial echocardiographic examination, we evaluated thickening and stiffening of artificial chordae and the effect of those changes on mitral valve function.

METHODS AND RESULTS

Between November 1986 and November 1993, 40 patients underwent mitral valve repair with artificial chordae using glutaraldehyde-tanned xenograft pericardium (GTXP) or polytetrafluoroethylene suture (PTFE). Seven GTXP patients and 20 PTFE patients underwent serial echocardiographic examination after surgery and were included in the final analysis. Thickening and stiffening of the artificial chonlae were classified according to echocardiographic changes after surgery: grade 1, no change; grade 2, thickening and/or stiffening without impairment of the motion of the mitral valve leaflet; and grade 3, thickening and stiffening that impaired motion of the mitral valve leaflet. The mean follow-ups in patients with GTXP and PTFE were 6.0 and 3.6 years, respectively. During follow-up, there were 2 GTXP patients with grade 2 thickening and stiffening and 4 patients with grade 3. There were 6 PTFE patients with grade 2 thickening and stiffening and 2 patients with grade 3. Grade 3 occurred earlier in GTXP than in PTFE patients (P < .05). Mitral valve area in GTXP patients decreased from 2.5 +/- 0.4 to 2.1 +/- 0.3 cm2 (P < .05); however, mitral valve area in PTFE patients showed no significant change during follow-up (2.1 +/- 0.4 to 2.0 +/- 0.4 cm2, P = NS).

CONCLUSIONS

Although mitral valve repair with artificial chordae is useful, more attention should be paid to mitral valve function resulting from thickening and stiffening of artificial chordae.

Identification of pseudonormal transmitral flow pattern using color Doppler echocardiography

The jet size of flow in color Doppler is dependent on both jet momentum and the compliance of the receiving chamber. Thus, the jet size of left ventricular (LV) late filling standardized by its jet momentum should reflect LV compliance. We investigated the feasibility of using color Doppler echocardiography to differentiate a pseudonormal from a normal transmitral flow pattern. We divided 37 patients with ischemic heart diseases who demonstrated a "normal" transmitral flow pattern into 2 groups according to their LV end diastolic pressure (LVEDP): a pseudonormalization group (LVEDP > or = 18 mmHg, 16 patients), and a normal group (LVEDP < 18 mmHg, 21 patients). We measured the maximum color Doppler jet length (L) and the peak velocity of transmitral flow during atrial contraction (Av). Filling volume (Q) was measured as the increase in LV volume during atrial contraction. A simplified jet momentum index (M) was obtained from Av x Q, and L/M was considered to reflect LV compliance. L/M was significantly lower in the pseudonormalization group that in the normal group (1.55 +/- 0.46 x 10(-3) vs 2.72 +/- 0.59 x 10(-3) p < 0.01). On the other hand, conventional Doppler variables such as isovolumic relaxation time and the deceleration time of early diastolic filling were not sufficient for discriminating between the 2 groups. In conclusion, color Doppler echocardiogram during atrial contraction was useful for differentiating a pseudonormal from a normal transmitral flow pattern.

Purification and characterization of arginine:mono-ADP-ribosylhydrolase from Euglena gracilis Z

Arginine:mono-ADP-ribosylhydrolase was purified from a protozoan, Euglena gracilis Z, using [32P]mono-ADP-ribosylated actin as a substrate. The enzyme showed molecular mass of 33 kDa both in SDS PAGE and gel filtration, indicating it to be a monomeric protein. It was strongly inhibited by ADP and ADP-ribose and activated by Mg2+, DTT, and 2-mercaptoethanol. These results suggest that it recognizes the ADP-ribose moiety of the modified protein. Since the enzyme activity increased in S phase and late G0 phase in a synchronous dividing culture, the enzyme may function in the regulation of the cell cycle.

Brain capillary endothelial cells express two forms of erythropoietin receptor mRNA

To study the existence of the erythropoietin receptor (Epo-R) mRNA in brain capillary endothelial cells, the reverse transcription (RT) PCR was performed using total RNAs from rat brain capillary endothelial cells (RBECs) and MBEC4, which is one of the established mouse brain capillary endothelial cell lines. Southern analysis of the RT-PCR products indicated that both RBECs and MBEC4 expressed an authentic form of Epo-R mRNA as a minor form and an intron-5-inserted form of Epo-R mRNA, thus a soluble form of Epo-R mRNA, as a major form. Furthermore, the effect of recombinant human erythropoietin (rHuEpo) on the DNA synthesis in RBECs was analyzed. rHuEpo showed a dose-dependent mitogenic action on RBECs as a competence factor. Radioiodinated rHuEpo was bound specifically to RBECs with time, cell number and dose dependencies. Binding studies with 125I-rHuEpo showed that RBECs had a single class of receptors with low-affinity (Kd = 860 pM) and that the number of sites/cell (10300) was abundant. These results suggest that brain capillary endothelial cells express not only an authentic form of Epo-R but also a soluble form of Epo-R and that erythropoietin acts directly on brain capillary endothelial cells as a competence factor.

Accumulation of methylmalonic acid caused by vitamin B12-deficiency disrupts normal cellular metabolism in rat liver

To clarify the relationship between intracellular concentrations of methylmalonic acid and metabolic and growth inhibition in vitamin B12-deficient rats, hepatic methylmalonic acid levels were assayed and inhibition of glucose and glutamic acid metabolism by methylmalonic acid was studied in isolated hepatocytes. Vitamin B12-deficient rats (14 weeks old) excreted more urinary methylmalonic acid and had lower body weights than the control rats. Hepatic methylmalonic acid levels (3.6(SD 1.30)-5.3 (SD 0.51) mumol/g tissue; 7.9 (SD 2.90)-11.8 (SD 1.14) mM) were increased and correlated with the extent of the growth retardation during vitamin B12-deficiency. Isolated hepatocytes and mitochondria from normally fed rats were labelled with [14C(U)]glucose and [14C(U)]glutamic acid respectively, in the presence or absence of 5 mM-methylmalonic acid. Although methylmalonic acid did not affect the incorporation of 14C into protein and organic acid fractions in the hepatocytes, it inhibited 14CO2 formation (an index of glucose oxidation by the Krebs cycle) by 25% and incorporation of 14C into the amino acid fraction by 30%. In the mitochondria, methylmalonic acid inhibited 14CO2 formation (indicating glutamic acid oxidation by the Krebs cycle) by 70%, but not the incorporation of 14C into the protein fraction. The incorporation of 14C into the organic acid fraction was significantly stimulated by the addition of methylmalonic acid. These results indicate that the unusual accumulation of methylmalonic acid caused by vitamin B12-deficiency disrupts normal glucose and glutamic acid metabolism in rat liver, probably by inhibiting the Krebs cycle.

Serial doppler echocardiographic evaluation of bioprosthetic valves in the tricuspid position

OBJECTIVES

This study sought to evaluate bioprosthetic valve dysfunction in the tricuspid position by serial Doppler echocardiography.

BACKGROUND

Few reports on the long-term results of tricuspid valve replacement with bioprosthetic valves are evaluated by serial Doppler echocardiography.

METHODS

Between September 1979 and December 1993, 95 patients underwent tricuspid valve replacement with bioprosthetic valves at our facility. Sixty patients who underwent serial Doppler echocardiographic examination at intervals of at least 2 years after operation were included in the final analysis. These patients were followed up from 1.5 to 13.0 years (mean 5.8 +/- 2.5).

RESULTS

The actuarial rates of freedom from bioprosthetic valve stenosis and regurgitation at 10 years were 46% and 51%, respectively. The prevalence of bioprosthetic valve stenosis and regurgitation increased progressively in a linear manner beginning 1 or 2 years after tricuspid valve replacement. Right heart failure developed during follow-up in 20 of the 25 patients with bioprosthetic valve dysfunction.

CONCLUSIONS

The long-term durability of bioprosthetic valves in the tricuspid position was substantially lower in our study than that reported in previous studies. Tricuspid bioprosthetic valve dysfunction increased progressively in a linear manner beginning 1 to 2 years after tricuspid valve replacement.

Endothelins contract guinea-pig pulmonary artery and enhance its adrenergic response via ET(A) receptors

1. This study has pharmacologically characterized endothelin (ET) receptor subtype(s) mediating contraction and enhancement of adrenergic contraction in guinea-pig pulmonary artery. Isometric tension of the isolated endothelium-denuded ring preparations was measured in the presence of indomethacin (10(-5) mol/L) and N(G)-nitro-L-arginine methyl ester (L-NAME; 3 x 10(4) mol/L) to exclude a mechanism via endothelium, cyclo-oxygenase-generated eicosanoids and nitric oxide. 2. In the additional presence of tetrodotoxin (TTX; 3 x 10(-7) mol/L), ET-1 (10(-11)-10(-7) mol/L) concentration-dependently contracted the preparations. The rank order of potency to contract the preparations among ET receptor agonists was ET-1, sarafotoxin (STX)6b > ET-3 > IRL 1620, STX 6c. BQ-123 (7 x 10(-7)-7 x 10(-6) mol/L) concentrations-dependently shifted the concentration-contraction curve for ET-1 to the right in a parallel manner. Pretreatment with STX 6c (3 x 10(-7) mol/L for 30 min) did not significantly desensitize contractions to ET-1, ET-3 or IRL 1620 (P > 0.05; t-test, 10 d.f). 3. ET-1 (10(-10)-10(-9) mol/L) and STX 6b (10(-9)-10(-8) mol/L) significantly enhanced the electrical field stimulation-induced contraction in a BQ-123-sensitive manner (P < 0.05: t-test, 24-38 d.f), while ET-3 (10(-11)-10(-8) mol/L) and STX 6c (10(-11)-10(-7) mol/L) did not affect contractions. ET-1 (10(-11) mol/L) significantly enhanced contractions to exogenous noradrenaline in the presence of TTX (3 x 10(-7) mol/L) (P < 0.05; t-test, 16 d.f.). 4. These data indicate that the BQ-123-sensitive ET(A) receptor mediates both contraction and enhancement of adrenergic contractions in the guinea-pig pulmonary artery.

Wall composition in intravascular ultrasound layered appearance of human coronary artery

To evaluate the impact of histological factors on the appearance of the wall of the coronary artery by intravascular ultrasound (IVUS), we performed an in vitro study of 34 coronary artery segments from eight autopsied patients. We assumed the coronary cross section to be divided into four equal parts, and assessed the quadrants with maximal and minimal wall thickness by IVUS (30 MHz; 4.3 Fr; 1800 rpm) and by a histological study. The histological layer thickness and composition were also evaluated in terms of their contribution to the appearance of the ultrasound layer. Fifty-eight quadrants were clearly visible on ultrasound. A three-layered appearance, with inner echogenic, subjacent sonolucent, and outer echogenic layers, was observed in 32 quadrants, while 26 quadrants showed a two-layered appearance with inner and outer echogenic layers. The thickness of the inner echogenic layer (0.77 +/- 0.38 mm) was moderately correlated with the intimal thickness (0.51 +/- 0.45 mm; r = 0.85, standard error of estimate [SEE] = 0.24 mm); however, the correlation was significantly improved when the thickness of the inner echogenic plus sonolucent layers (0.89 +/- 0.47 mm) was compared with that of the intima plus media (0.69 +/- 0.47 mm; r = 0.94, SEE = 0.15 mm; P = 0.012 between the coefficients). Discriminant analysis showed that intimal hyalinization, associated with intimal thickening, was strongly related to the presence of the three-layered appearance on IVUS (F to enter 40.0, P < 0.0001). These results indicate that the ultrasound layered appearance of human coronary arteries varies with histological alterations. We suggest that the thickness of the inner echogenic plus sonolucent layers on IVUS represents the intimal plus medial thickness observed by histology, and that the use of this value may be appropriate in the assessment of coronary wall thickening associated with atherosclerosis.

Hypoxia inhibits gastric emptying and gastric acid secretion in conscious rats

This study examines the effects of hypoxia in the gastric function in conscious rats which adapted to a meal-feeding schedule, that allowed free access to a high protein (HP) diet (550 g casein/kg diet, Exp.1,2 and 4), a normal protein (NP) diet (200 g casein/kg diet, Exp.3) or a nonpurified rat (NPR) diet (Exp. 5 and 6) for 4 h every day for 2 wk. In Exp. 1, after 4 h of consuming the HP diet, rats were exposed to 7.6 or 10.5% O2 normobaric hypoxia. Hypoxia delayed the excretion of urinary urea for 12 h. In Exp.2 and 3, when rats were exposed to 7.6%O2 after 4 h of consuming the HP diet and exposed to 10.5% O2 after 4 h of consuming the NP diet, respectively, a significant delay in gastric emptying was found in the hypoxic rats. In Exp. 4, when rats were exposed to 7.6 O2 hypoxia after 4 hr of eating the HP diet, the plasma gastrin concentration in the 7.6% O2 hypoxic rats was 2.3-fold that of the normoxic rats after 6 h of hypoxia. Furthermore, when rats that did not consume any HP diet on the day of the experiment were exposed to 7.6 or 10.5% O2 hypoxia, the plasma gastrin concentration was higher in both hypoxic groups than in the normoxic group after 3 and 6 of hypoxia. In Exp. 5, rats that were not fed the NPR diet on the day of study were exposed to 7.6 or 10.5% O2 hypoxia for 3 h after pylorus ligation. Hypoxia inhibited the secretion of gastric acid and elevated the plasma gastrin concentration. In Exp. 6, unfed rats that had been consuming the NPR diet were exposed to 7.6% O2 hypoxia for 3 h after pylorus ligation and were orally administered HCl. The rise of the gastrin concentration due to hypoxia was completely inhibited by oral HCl. These results demonstrate that hypoxia inhibits gastric emptying and gastric acid secretion and that the inhibitory effect of hypoxia on gastric acid secretion stimulates gastrin release through positive feedback regulation.

Changes of plasma atrial and brain natriuretic peptide levels during hemodialysis

OBJECTIVES

The purpose of this study was to evaluate the effect of hemodialysis on the plasma concentration of atrial and brain natriuretic peptides, and to determine the two-dimensional echocardiographic parameters affecting the changes of plasma atrial and brain natriuretic peptide levels in patients with chronic renal failure.

BACKGROUND

Brain natriuretic peptide has been found in human cardiac tissue and increases in patients with congestive heart failure. However, the factors that stimulate the secretion of plasma brain natriuretic peptide have not yet been fully clarified.

METHODS

In 15 patients with chronic renal failure, plasma atrial and brain natriuretic peptide levels and two-dimensional echocardiographic parameters were measured before and after each session of hemodialysis.

RESULTS

Plasma atrial natriuretic peptide levels significantly decreased from 367 +/- 537 pg/mL to 138 +/- 167 pg/mL after hemodialysis (p < 0.01). However, plasma brain natriuretic peptide levels did not significantly change after hemodialysis. Left atrial dimension significantly decreased (41.1 +/- 6.6 vs. 36.3 +/- 6.2 mm, p < 0.01) and left ventricular end-diastolic dimension slightly decreased after hemodialysis (57.0 +/- 10.3 vs. 55.7 +/- 9.9 mm, p < 0.05). The decrease of left atrial dimension was greater than that of left ventricular end-diastolic dimension (4.9 +/- 1.6 vs. 1.3 +/- 0.6 mm, p < 0.05). Plasma brain natriuretic peptide levels significantly correlated with fractional shortening both before and after hemodialysis (r = 0.65, p < 0.05).

CONCLUSION

Plasma atrial natriuretic peptide levels significantly decreased as the right and left atrial overloads decreased, and plasma brain natriuretic peptide levels did not significantly decrease after hemodialysis. Plasma brain natriuretic peptide levels were not significantly influenced by acute hemodynamic change, such as hemodialysis. However, plasma brain natriuretic peptide levels were significantly correlated with basic cardiac function.

Functional behavior and morphology of the coronary artery wall in patients with Kawasaki disease assessed by intravascular ultrasound

OBJECTIVES

To examine the development of coronary artery lesions in Kawasaki disease, we assessed the functional behavior and morphology of coronary arteries by intravascular ultrasound.

BACKGROUND

Long-term follow-up studies of patients with Kawasaki disease have demonstrated the development of localized coronary stenoses even after aneurysms have regressed. It is also possible that angiographically normal coronary segments in patients with this disease may retain histologic changes.

METHODS

Twenty-three patients followed up by serial coronary angiography were examined at a mean age +/- SD of 14.9 +/- 2.9 years. The thickness of the intima-media complex was measured by intravascular ultrasound (30 MHz; 3.5 or 4.3 F; 1,800 rpm). Coronary reactivity to nitroglycerin was determined by measuring percent changes in cross-sectional coronary artery area after intracoronary injection (7 microgram/kg body weight) of this agent.

RESULTS

A remarkably thickened intima-media complex was observed at the sites with persisting (0.54 +/- 0.20 mm, n = 19) and regressed (0.84 +/- 0.40 mm, n = 23) aneurysms. Mild thickening of the intima-media complex was often observed even in angiographically normal segments (0.22 +/- 0.05 mm, n = 31), in the left main coronary artery (0.47 +/- 0.15 mm, n = 20) and at normal branches (0.36 +/- 0.09 mm, n = 13). Coronary reactivity to nitroglycerin was significantly lower at the sites of regressed aneurysms (12.8 +/- 6.6%, n = 9) than in normal segments (32.8 +/- 10.9%, n = 13, p < 0.01), indicating the presence of functional impairment at the sites with regressed aneurysms. Decreased nitroglycerin reactivity was also observed in some segments without evidence of aneurysm.

CONCLUSIONS

These results indicate that in patients with Kawasaki disease the coronary disease accompanying impaired reactivity to nitroglycerin is present at the sites of regressed aneurysms as well as in angiographically normal coronary segments. We suggest that these sites with morphologic and functional abnormalities are related to the development of significant stenosis.

Intravascular ultrasound evidence of angiographically undetected left main coronary artery disease and associated trauma during interventional procedures

To determine the clinical significance of angiographically undetected left main coronary artery (LMCA) disease, we analyzed data from 47 patients, with a mean age of 58 years, who were examined with intravascular ultrasound (3.5 Fr, 30 MHz). For assessment of atherosclerosis, the lesion area was calculated from the ultrasound images of the formula, [(total vessel area--lumen area)/total vessel areas] x 100(%). In 37 LMCA segments of patients with significant distal coronary stenosis (> 50%), the percent intima-media area (the index) was 39 +/- 11% (mean +/- SD), significantly greater than that of 10 patients without distal disease (27 +/- 4%, P < 0.01). Among those with significant coronary stenosis, the index was markedly greater in patients with multi-vessel coronary stenosis (46 +/- 12%, n = 19) than in patients with single-vessel disease (33 +/- 9%, n = 18; P < 0.01). At three LMCA sites associated with multi-vessel disease, ultrasound analysis demonstrated disruption of the intima at the site where the guiding catheter for balloon angioplasty had been positioned. These results indicate that LMCA disease is more prominent in patients with multi-vessel distal coronary disease than in those with single vessel disease, even in the absence of angiographic stenosis. We suggest that LMCA trauma can occur where the guiding catheter for angioplasty is positioned, particularly in patients with multi-vessel distal disease.

[Gingival metastasis of large-cell lung cancer that produced G-CSF]

A 68-year-old man was referred to our hospital for further examination of a gingival mass. Chest radiographs and magnetic resonance imaging disclosed a bulky mass originating in the upper portion of the left lung, in contact with a chronic empyema lesion that first occurred after resection for pulmonary tuberculosis. Examination of a specimen obtained by percutaneous needle biopsy of the mass led to the diagnosis of large-cell carcinoma. Laboratory findings on admission showed marked leukocytosis (48,100/microliter) without evidence of severe a bacterial infection. The level of G-CSF in serum was abnormally high (246 pg/ml, normal value: < 30 pg/ml). Chemotherapy with vindesine, ifosfamide, and cisplatin resulted in shrinkage of the gingival mass, and a decrease in the G-CSF level to 66 pg/ml. Immunohistochemical staining with an anti-G-CSF monoclonal antibody to the primary lung tumor and the gingival mass obtained at autopsy was positive for cytoplasmic G-CSF.

Dental health indicator based on a questionnaire

Dentistry has lacked an effective indicator of the impact of dental problems on a person's daily life. Subjective factors in dental health need to be included in order to improve current indicators. The purpose of this research was to develop a new type of indicator recorded from a questionnaire which takes account of subjective factors in dental health. The indicator we constructed has the following advantages. 1. Calculation process is simple in practice. 2. The indicator values range from 0 to 100, with values closer to 100 indicating a more favorable condition for the individual. 3. The distribution of indicator values is similar to the normal distribution. 4. The score of each item is reflected on the indicator, suggesting the individual's characteristics in terms of dental health. 5. Although it is principally an indicator for individuals, it can also be applied to groups. This study will also provide a model for the preparation of a dental health indicator.

Methylmalonic acid inhibits respiration in rat liver mitochondria

Methylmalonic acid (MMA), which accumulates and is excreted in urine in mammals during vitamin B-12 deficiency, has been reported to inhibit succinate dehydrogenase, an enzyme involved in the mitochondrial tricarboxylic acid (TCA) cycle in rat liver. The enzyme inhibition by MMA may lead to various metabolic disorders as well as inhibition of mitochondrial energy generation in vitamin B-12-deficient mammals. To clarify the inhibition of succinate dehydrogenase by MMA in intact rat liver mitochondria, the effect of MMA on mitochondrial respiration was studied. When 6 mmol/L MMA was added to the reaction mixture for measuring mitochondrial respiration with succinate as a substrate, MMA was taken up and accumulated by the mitochondria (34-53 mmol/L). The accumulation of mitochondrial MMA was stimulated by the addition of ADP. Methylmalonic acid competitively inhibited State 3 mitochondrial respiration, and the Ki for the acid was 4.2 +/- 0.4 mmol/L. Although the respiratory control ratio decreased with increasing MMA concentration, the acid did not affect the phosphorus/oxygen ratio. Mitochondrial MMA accumulation secondary to vitamin B-12 deficiency inhibits succinate dehydrogenase and may contribute to various metabolic disorders associated with vitamin B-12 deficiency.

Different modes of sensory neuropeptides and nitric oxide involvement in relaxation of guinea-pig vessels

This study investigated involvement of calcitonin-gene-related peptide (CGRP), substance P (SP) and nitric oxide (NO) in transmural nerve stimulation (TNS)-induced non-adrenergic, non-cholinergic (NANC) relaxation in isolated guinea pig anterior mesenteric artery (AMA) and posterior caval vein (PCV). Effects of cyclo-oxygenase-generated eicosanoids were blocked with indomethacin (10(-5) M) and so were adrenergic and cholinergic responses with phentolamine (3 x 10(-6) M), propranolol (10(-6) M) and atropine (10(-6) M). In both vessels precontracted by U-46619, TNS induced relaxation, which was almost completely abolished by capsaicin pretreatment (10(-6) M, 15 minutes). In AMA, a CGRP1 receptor antagonist (human CGRP8-37, 10(-5) M) significantly attenuated the relaxation, while did both human CGRP8-37 (10(-5) M) and neurokinin-1 receptor antagonists (spantide, 2 x 10(-5) M and FK888, 3 x 10(-6) M) in PCV. NG-nitro-L-arginine methyl ester (10(-4) M) did not significantly attenuate either the NANC-or CGRP-induced relaxation in AMA. However, it significantly did attenuate both the NANC-and SP-induced relaxation, and it also considerably attenuated CGRP-induced relaxation although insignificantly, in PCV. Thus, CGRP could be significantly responsible for the NO-independent NANC relaxation in AMA, whereas both CGRP and SP could additionally relax PCV in a NO-dependent manner.

Salutary effect of disopyramide on left ventricular diastolic function in hypertrophic obstructive cardiomyopathy

OBJECTIVES

The purpose of this study was to estimate the effect of disopyramide on left ventricular diastolic function in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND

Although disopyramide has been reported to lessen clinical symptoms in patients with hypertrophic obstructive cardiomyopathy, few data exist regarding its effect on diastolic function in these patients.

METHODS

Thirteen patients with hypertrophic cardiomyopathy (six with and seven without left ventricular outflow obstruction) were examined. Before and after intravenous disopyramide, hemodynamic and angiographic studies were performed.

RESULTS

In patients with outflow obstruction, pressure gradient at the outflow tract decreased from a mean +/- SD of 100 +/- 45 to 26 +/- 33 mm Hg (p < 0.01). Although systolic function was similarly impaired in both groups, the time constant of left ventricular pressure decay (tau) shortened from 56 +/- 10 to 44 +/- 8 ms (p < 0.01) and the constant of left ventricular chamber stiffness (kc) decreased from 0.049 +/- 0.017 to 0.038 +/- 0.014 m2/ml (p < 0.01) only in patients with outflow obstruction. Shortening in tau correlated best with decrease in left ventricular systolic pressure (r = 0.84, p < 0.01). In contrast, tau was prolonged from 52 +/- 10 to 64 +/- 11 ms (p < 0.01) and kc was unchanged in patients without outflow obstruction.

CONCLUSIONS

The primary effects of disopyramide on the hypertrophied left ventricle were negative inotropic and negative lusitropic. However, left ventricular diastolic properties in patients with outflow obstruction were improved with a decrease in outflow pressure gradient. Relief of clinical symptoms in hypertrophic obstructive cardiomyopathy with disopyramide might be due in part to improvement of diastolic function, which appears secondary to the reduction in ventricular afterload.

Comparison of vessel wall morphologic appearance at sites of focal and diffuse coronary vasospasm by intravascular ultrasound

Coronary vasospasm is manifested by either focal or diffuse pattern in clinical settings. To examine the differences in vessel wall morphologic appearance between the sites of focal and diffuse vasospasm, we studied 29 patients with chest pain at rest, during exertion, or both by intravascular ultrasound. By angiography, focal vasospasm with diameter reduction of 90% +/- 3% (mean +/- SD) was provoked by intracoronary ergonovine (0.01 to 0.04 mg) in 15 patients. Diffuse vasospasm with diameter reduction of 79% +/- 5% (NS) was provoked in seven patients, and the remaining seven patients served as the control group. By ultrasonography, a significantly thickened intimal leading edge with sonolucent zone was observed in 55 sites from 22 coronary arteries with either focal or diffuse vasospasms (0.61 +/- 0.32 mm), although these sites were normal or minimally narrowed by angiography. Seven segments from the control group exhibited a thin intimal leading edge with sonolucent zone (0.23 +/- 0.08 mm, p < 0.01). When the thickness of the intimal leading edge with sonolucent zone was compared between the abnormal sites with focal and diffuse vasospasm, this was significantly greater at focal spasm, 1.01 +/- 0.35 mm (n = 15), than that at diffuse spasm, 0.46 +/- 0.13 mm (n = 40, p < 0.01). At the sites with diffuse spasm, some of the lesions lay scattered along the coronary vessels, although the lesions were localized at the sites of focal vasospasm. These results indicate that atherosclerosis is present at sites with both focal and diffuse vasospasm even in the absence of angiographically significant coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

[SH/TA-508 clinical phase II study: dose evaluation of SH/TA-508 in echocardiography]

A cooperative study was conducted at 18 institutions to evaluate the safety and usefulness of SH/TA-508, a contrast medium for ultrasound diagnosis, and to find its optimum dose. One hundred and one patients with confirmed or suspected ischemic heart disease were examined with two-dimensional echocardiography, and 95 patients with mild mitral insufficiency were studied with the color Doppler method. The contrast medium was administered at low-dose (1.5-1.6g galactose) and high-dose (3.0-3.2 g galactose) levels at concentrations of 200, 300 and 400 mg/ml. The contrast effect was evaluated into five grades by two-dimensional echocardiography: - (ineffective), + (weak), 2+ (moderate), 3+ (good), 4+ (excessive effect) and into four grades with the color Doppler method, - (ineffective), + (weak), 2+ (optimum), 3+ (excessive effect). The two-dimensional echocardiographic studies showed effects graded at 2+ and above in most patients (83-93%). These findings were significantly more common in patients who had received the 300 and 400 mg/ml concentrations than in those who received the 200 mg/ml concentration. Statistical analysis found no significant differences between the high-dose and low-dose groups. Color Doppler echocardiography found signal enhancement graded at 2+ and above in 80-93% of cases. There were no significant differences in enhancement effect attributable to concentration or total dose. However, since excessive signal intensity was seen quite frequently, the dose levels in the present study were considered to be a little too high. Side effects includes transient feelings of warmth or cold, and the incidence of side effects was higher at higher doses and concentrations. The results show that the optimum concentration for two-dimensional echocardiography is 300 mg/ml and for color Doppler 200 mg/ml. No particular safety problems were seen with SH/TA-508, and this contrast medium is useful in echocardiography of the left ventricle and in enhancing mitral regurgitation signals in color Doppler examinations. Therefore, a phase III multicenter trial should be performed.

Excretion from rats of ketone bodies and methylmalonic acid in urine resulting from dietary vitamin B12 deficiency

Ketone bodies were assayed in the urine of ten-week-old vitamin B12-deficient rats by a high-performance liquid chromatography. The urinary excretion of ketone bodies (352.5 +/- 68.3 mumol/day) as well as of methylmalonic acid was increased significantly by dietary vitamin B12 deficiency.

[Characteristics of regional sympathetic dysfunction in acutely ischemic myocardium assessed by 123I-metaiodobenzylguanidine imaging: impairment of myocardial norepinephrine uptake or retention]

To characterize regional cardiac sympathetic dysfunction due to myocardial ischemia, we examined 123I-metaiodobenzylguanidine (MIBG) myocardial distribution of initial 15-min and 4-hr delayed SPECT images in 14 patients with recent myocardial infarction (MI), 25 patients with vasospastic angina which was angiographically proven with elgonovine maleate (Gp VSAP) and 16 patients with chest pain syndrome and normal CAG findings (GpCP). In those with MI, the study was serially done at 2 weeks after (Gp MI-1) and at 3 months after the onset of MI (Gp MI-2). We estimated regional tracer uptake in 20 segments of tomographic images by using a 4-point scoring system (0 = normal, 1 = mild, 2 = moderate, 3 = severe reduction) and calculated the total defect score (IDS). In all patients with MI, the area of reduced MIBG uptake was more extensive than the 201Tl perfusion defect in the acute stage (Gp MI-1) indicating the presence of viable but denervated myocardial tissue. Also, the MIBG defect was persistently observed from initial (TDS: 24 +/- 13) to delayed imaging (TDS: 26 +/- 12). However, in the chronic stage (Gp MI-2), the initial MIBG uptake improved (TDS: 18 +/- 9) but the delayed uptake remained almost the same (TDS: 22 +/- 10) indicating high washout of MIBG from the ischemic myocardium. Fourteen in Gp VSAP and 14 in Gp CP showed the regional MIBG defect in the delayed image more extensively than in the initial image indicating high washout of MIBG in the involved myocardial regions. These results suggest that neuronal uptake of MIBG is impaired in the acute stage of MI although neuronal retention of MIBG is predominantly impaired in the chronic stage of MI or in Gps VSAP and CP.

Myocardial velocity gradient as a new indicator of regional left ventricular contraction: detection by a two-dimensional tissue Doppler imaging technique

OBJECTIVES

This study was performed to assess a new indicator of regional left ventricular contraction determined by a two-dimensional tissue Doppler imaging technique.

BACKGROUND

Recent studies have demonstrated that instantaneous tissue motion velocity can be noninvasively assessed by tissue Doppler imaging. However, quantitative assessment of regional left ventricular contraction is still difficult because of the effects of the Doppler angle of incidence and parallel motion of the whole heart.

METHODS

We assessed left ventricular wall motion in 11 normal subjects, 14 patients with an old myocardial infarction (anteroseptal in 7, posterior in 7) and 8 patients with dilated cardiomyopathy. Tissue Doppler velocity was corrected by the Doppler angle of incidence after the hypothetical center of contraction was set. Subsequently, the myocardial velocity gradient between the endocardium and epicardium was determined from the velocity profile along each radial line from the center of contraction by using least squares linear regression.

RESULTS

In normal subjects, peak myocardial velocity gradient was lower in the anteroseptal wall (mean [+/- SD] 1.69 +/- 0.53 s-1) than in the posterior wall (3.28 +/- 0.67 s-1, p < 0.01). Myocardial velocity gradient in the infarct regions was significantly lower (anteroseptal 0.58 +/- 0.41 s-1, p < 0.05; posterior 0.17 +/- 0.27 s-1, p < 0.01) than that in normal subjects as well as that in the corresponding noninfarct regions (2.84 +/- 0.37 s-1 and 1.48 +/- 0.25 s-1, p < 0.01, respectively). In patients with dilated cardiomyopathy, myocardial velocity gradient was generally lower (anteroseptal 0.72 +/- 0.59 s-1; posterior 0.93 +/- 0.67 s-1) than that in normal subjects (p < 0.01).

CONCLUSIONS

These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity gradient derived from two-dimensional tissue Doppler imaging. We suggest that myocardial velocity gradient has potential for the quantitative assessment of regional left ventricular contraction abnormalities in patients.

Assessment of coronary artery distensibility by intravascular ultrasound. Application of simultaneous measurements of luminal area and pressure

BACKGROUND

Atherosclerotic change in the coronary artery is associated with an impaired vessel wall distensibility. However, there are few data regarding the relation between vessel wall morphology and distensibility. Therefore, with intravascular ultrasound, we assessed coronary artery distensibility in angiographically normal coronary segments of humans.

METHODS AND RESULTS

Data were analyzed at 35 angiographically normal coronary sites where circumferential or noncircumferential lesions were demonstrated by ultrasound in 22 patients (mean age, 55 years). After intracoronary injection of 500 micrograms nitroglycerin (NTG), coronary luminal area was measured with intravascular ultrasound (30 MHz, 3.5F to 4.3F, 1800 rpm). Intracoronary pressure was simultaneously measured with a 2F micromanometer-tipped catheter located at the left main coronary artery. The coronary distensibility index was calculated as 10-fold the ratio of luminal area change to intracoronary pressure change during a cardiac cycle. Another pressure-independent vascular stiffness index, beta, was derived by the following formula: beta = [ln(SBP/DBP)]/(dD/diastolic mean diameter), where SBP is systolic intracoronary pressure, DBP is diastolic intracoronary pressure, and dD is the difference between systolic and diastolic diameters. At the sites where luminal areas were measured, thickness of intima-media complex, defined as the distance between the intimal leading edge and the adventitial leading edge, was determined as an index of the severity of atherosclerosis. In seven segments, distensibility index was determined before and after NTG injection to examine the effect of NTG on coronary distensibility. In all examined sites, including circumferential and noncircumferential lesions, the luminal area was 12.6 +/- 5.0 mm2 during systole and 11.6 +/- 4.6 mm2 during diastole, and the calculated coronary distensibility index ranged from 0 to 0.83 mm2/mm Hg. The thickness of the intima-media complex ranged from 0.12 to 1.30 mm, suggesting the presence of various grades of atherosclerosis even in the absence of angiographic lesions. There was a poor inverse correlation between thickness of the intima-media complex and distensibility index (r = .19, y = -0.17x + 0.41, P = .29). However, when noncircumferential lesions were excluded for evaluation, there was a significant inverse correlation between them (r = .58, y = -0.50x + 0.72, P < .01). Under these conditions, the thickness of the intima-media complex also correlated with the value of beta (X10(-1), which ranged from 0.28 to 3.99 (r = .70). After NTG injection, coronary distensibility increased by an average of 71% in the segments with a thin intima-media complex, whereas it did not substantially change in those with a relatively thick intima-media complex.

CONCLUSIONS

These results suggest that coronary distensibility is impaired in the coronary sites accompanying occult atherosclerosis, none of which can be detected by the conventional angiography. NTG can augment coronary distensibility in the segments without a markedly thickened intima-media complex. We suggest that thickness of the intima-media complex can contribute to determining the coronary distensibility in clinical settings.

Mitochondrial alcohol dehydrogenase from ethanol-grown Euglena gracilis

The inducing effects of ethanol on alcohol dehydrogenase and the key enzymes of the glyoxylate cycle, isocitrate lyase and malate synthase, in Euglena cells were investigated. Ethanol as the sole carbon source resulted in increases in alcohol dehydrogenase and the two glyoxylate cycle enzymes. The experimental results indicated that ethanol is assimilated by alcohol dehydrogenase and the glyoxylate cycle in Euglena. Mitochondria from aerobically grown Euglena contain a unique type of alcohol dehydrogenase that accounts for their ability to respire with ethanol as a substrate. This alcohol dehydrogenase was purified to homogeneity from ethanol-grown Euglena gracilis. The mitochondrial alcohol dehydrogenase was NAD(+)-specific but not NADP(+)-specific. Ethanol was the most active substrate, but the enzyme was also active towards 1-butanol, 1-heptanol, cinnamyl alcohol, and myristyl alcohol. These results indicated that mitochondrial alcohol dehydrogenase participated in alcohol metabolism in Euglena gracilis.

Inhibitory effects of perillosides A and C, and related monoterpene glucosides on aldose reductase and their structure-activity relationships

Monoterpene glucosides, perillosides A and C, obtained from the leaves of Perilla frutescens, were found to be inhibitors of aldose reductase (EC 1.1.1.21) which is considered to be a key enzyme in diabetic complications such as cataract. The apparent type of inhibition of rat lens aldose reductase by perillosides A and C was competitive with respect to glyceraldehyde and their K(i) values were 1.4 x 10(-4) and 2.3 x 10(-4) M, respectively. The type of inhibition by their tetraacetates was non-competitive with respect to the same substrate, although their inhibitory effects were increased by about one order of magnitude compared with those of the perilllosides and the K(i) values were 2.5 x 10(-5) and 7.1 x 10(-5) M, respectively. We also prepared related monoterpene glucosides and their tetraacetates and determined their inhibitory activities towards aldose reductase in order to elucidate the relationship between structure and inhibitory activity.

Perfusion lung scanning before and after percutaneous transvenous mitral commissurotomy--early estimation of lung congestion relief

Percutaneous transvenous mitral commissurotomy (PTMC) has recently been used to treat mitral stenosis. The aim of this study was to evaluate the usefulness of radionuclide perfusion lung scanning in assessing the effect of PTMC on the relief of lung congestion. We studied 30 patients (7 males and 23 females, mean age 55 years). Perfusion lung scannings were performed within 1 week before and after PTMC. We calculated the ratio of activity in the upper quarter to that in the lower quarter of the right lung (U/L) as an index of lung congestion. After PTMC, the mean mitral valve area increased from 1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, the mean left atrial pressure decreased from 14.8 +/- 6.3 to 9.1 +/- 3.5 mmHg, the mean pulmonary artery pressure decreased from 22.7 +/- 8.6 to 17.4 +/- 6.3 mmHg, and the U/L ratio decreased significantly from 0.89 +/- 0.40 to 0.68 +/- 0.24 (p < 0.0001). The U/L ratio showed greater improvement (4.5%) in patients whose NYHA class improved (n = 19) than in those whose NYHA class did not improve after PTMC. The U/L ratio was closely related to mitral valve area, and left atrial and pulmonary artery pressures. The change in the U/L ration before and after PTMC also reflected symptomatic improvement. In conclusion, U/L ratios obtained from perfusion lung scannings before and after PTMC reflect mitral valve area and pressures, and can be used to assess lung congestion relief after PTMC.

Pharmacodynamics of 15(S)-hydroperoxyeicosatetraenoic (15-HPETE) and 15(S)-hydroxyeicosatetraenoic acid (15-HETE) in isolated arteries from guinea pig, rabbit, rat and human

The vasoactive properties of 15(S)-hydroperoxyeicosatetraenoic acid (15-HPETE) and 15(S)-hydroxyeicosatetraenoic acid (15-HETE) were characterized in aortic rings of guinea pig (GPA), rat (RA) and rabbit (RbA), as well as pulmonary arteries from guinea pigs (GPPA) and humans (HPA). Four distinct patterns of activity were identified: 1) Cyclooxygenase-dependent relaxation (in GPA, GPPA and HPA). This could be speculated to be due to release of prostaglandin I2 or to conversion of 15-H(P)ETE to another vasorelaxant eicosanoid(s). The endothelium was the main source of this activity in GPA but not in HPA. 2) Cyclooxygenase-independent relaxation mediated by both endothelium and the smooth muscle proper (only in RA). 3) Endothelium-dependent contraction associated with the release of unknown factor(s) (in GPA, GPPA and HPA). 4) Endothelium-independent contraction (in RbA). Nitric oxide was not involved in the relaxation of GPA and RA, nor was endothelin in the contraction of GPA. 15-HPETE and 15-HETE always elicited analogous responses in the same preparations, probably because of rapid metabolism of 15-HPETE into 15-HETE or, even more likely, because both eicosanoids have identical modes of action. We concluded that depending on factors such as the species, the dose of the compounds and the presence of other vasoregulators, the overall response to 15-HPETE or 15-HETE may be vasodilation or vasoconstriction. In addition, the type of responses elicited with 15-HPETE and 15-HETE in RbA and RA differed conspicuously from those expressed in GPA, GPPA and HPA.

New method for evaluating left ventricular wall motion by color-coded tissue Doppler imaging: in vitro and in vivo studies

OBJECTIVES

The aim of this study was to examine the accuracy and validity of a newly developed tissue Doppler imaging system in in vitro and in vivo studies.

BACKGROUND

Because quantitative measurement of wall motion velocity in real time is still difficult by conventional echocardiography, we developed a new system for evaluating ventricular wall motion by analyzing Doppler signals from cardiac tissue.

METHODS

We used a modified Doppler color imaging system, omitting the high pass filter to allow Doppler signals from cardiac tissue to enter the auto-correlator. Ultrasound carrier and pulse repetition frequencies were 3.75 MHz and 3.0 to 6.0 kHz, respectively. Under these conditions, the lowest measurable velocity was 0.2 cm/s.

RESULTS

In the rotating sponge model, the measured velocity correlated well with the actual velocity (y = 0.97x + 2.17, r = 0.99). In clinical settings, the mid-ejection mean velocity at either endocardial or epicardial sites of the left ventricular posterior wall measured by M-mode tissue Doppler imaging correlated well with that measured by conventional M-mode echocardiography (y = 0.94x + 0.64, r = 0.99). During systole, in healthy subjects, the anterior left ventricular wall was color-coded blue and the posterior wall was color-coded red, whereas the akinetic regions associated with myocardial infarction showed no color throughout the cardiac cycle. The ventricular posterior wall excursion velocity, defined as the difference between velocities at the endocardial and epicardial sites, was significantly slower in patients with dilated cardiomyopathy (0.4 +/- 0.3 cm/s) than in normal subjects (2.0 +/- 0.6 cm/s).

CONCLUSIONS

These results indicate that the present system accurately represents tissue velocity and can create two-dimensional color images that facilitate visual assessment of ventricular wall motion.

[Prediction of ineffective outcome of surgical treatment for constrictive pericarditis]

The preoperative factors predicting the outcome of surgical treatment for constrictive pericarditis were investigated in 22 patients with constrictive pericarditis who underwent pericardiectomy. The NYHA functional class was improved in nine patients after surgery (improved group), but not in the other 13 patients (unimproved group). Preoperative right and left heart catheterization data and echocardiograms were compared between these two groups. Right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP) were significantly higher in the unimproved group. The left atrial diameter (LAD) measured by echocardiography was significantly greater in the unimproved group. These results indicate that pericardiectomy will cause a worsened immediate outcome in patients with severe pericardial constriction. LAD was the most useful parameter in predicting the ineffectiveness of the pericardiectomy. If the borderline value of LAD is taken as 40 mm, the sensitivity and specificity predicting ineffective surgery were 92% and 89%, respectively. RAP and PCWP could not separate the two groups satisfactorily. Pericardiectomy should be performed before the pericardial constriction progresses, and before LAD reaches 40 mm.

[Feasibility of the left ventricular volume measurement by acoustic quantification method: comparison with ultrafast computed tomography]

Acoustic quantification (AQ: the real-time automated boundary detection system) allows instantaneous measurement of cardiac chamber volumes. The feasibility of this method was evaluated by comparing the left ventricular (LV) volumes obtained with AQ to those derived from ultrafast computed tomography (UFCT), which enables accurate measurements of LV volumes even in the presence of LV asynergy, in 23 patients (8 with ischemic heart disease, 5 with cardiomyopathy, 3 with valvular heart disease). Both LV end-diastolic and end-systolic volumes obtained with the AQ method were in good agreement with those obtained with UFCT (y = 1.04 x - 16.9, r = 0.95; y = 0.87x + 15.7, r = 0.91; respectively). AQ was reliable even in the presence of LV asynergy. Interobserver variability for the AQ measurement was 10.2%. AQ provides a new, clinically useful method for real-time accurate estimation of the left ventricular volume.

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report]

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

Consequence of diseases in aorta on evaluation of aortic regurgitation by aortic flow velocity profiles

The aim of the study was to investigate whether flow velocity profiles of the aorta are related to the severity of aortic valve regurgitation (AR) in patients with diseases of the aorta. Aortic root angiography, abdominal aortic flow velocity measurements by pulsed Doppler method, and regurgitant jet measurements by color Doppler echocardiography were performed in 62 patients with various etiologies of AR and 13 patients without AR. The regurgitant fraction of abdominal aortic flow velocity profiles was related to the angiographic severity of AR except for the patients with Takayasu's arteritis and those after thoracic aorta grafting who showed large regurgitant fraction regardless of AR. Color Doppler evaluation was also correlated well with angiographic findings, but it was not possible in 13 of 62 patients with AR because of the inadequate color Doppler images. Although the observation of abdominal aortic flow profiles is clinically of value in noninvasive evaluation of AR, it could not be applied in patients with Takayasu's arteritis and those after graft surgery.

Cytochrome b5-like hemoprotein/cytochrome b5 reductase complex in rat liver mitochondria has NADH-linked aquacobalamin reductase activity

Rat liver mitochondrial NADH-linked aquacobalamin reductase was characterized to clarify its enzymological properties. Most of the enzyme was solubilized with 10 g/L Triton X-100 from rat liver mitochondrial membranes. The elution behavior of the solubilized enzyme was identical to that of NADH-cytochrome c reductase (b-type cytochromes/cytochrome b5 reductase complex) during DEAE-Sepharose Fast Flow column chromatography. By mixing both purified cytochrome b5-like hemoprotein (outer membrane-cytochrome b) and cytochrome b5 reductase, cob(II)alamin was formed from aquacobalamin and NADH. These results provide evidence that the outer membrane-cytochrome b/cytochrome b5 reductase complex has the activity of the NADH-linked aquacobalamin reductase in rat liver mitochondria. Some properties of the NADH-linked aquacobalamin reductase were studied using the function of rat liver mitochondrial membranes. The specific activity (109.5 +/- 14.3 nmol.min-1.mg protein-1) of the enzyme was shown under physiological conditions (pH 7.1 at 40 degrees C). The optimal pH and temperature for activity were 7.1 and 40 degrees C, respectively. The apparent Km values were 41.9 mumol/L for aquacobalamin in the presence of 0.2 mmol/L NADH and 14.4 mumol/L for NADH in the presence of 0.1 mmol/L aquacobalamin. The enzyme was specific for aquacobalamin, because cyanocobalamin could not be reduced by the enzyme.

Myocardial involvement in patients with sarcoidosis. An analysis of 75 patients

The authors studied 75 nonselected patients (30 men and 45 women; mean age 48 years) with sarcoidosis retrospectively to assess the applicability of nuclear examinations for detecting myocardial involvement. All patients were studied with Tl-201 myocardial perfusion scan (TMPS), Ga-67 myocardial scan (GMS), and left ventricular ejection fraction (LVEF) using ECG-gated radionuclide ventriculography. The positive GMS group had a significantly higher occurrence of abnormality on TMPS (100%) than the negative GMS group (41%). Patients with TMPS abnormality and positive GMS showed significantly lower LVEF (36.3%) than those of normal perfusion or negative GMS. When LVEF decreased, occurrences of TMPS abnormality and positive GMS increased. The authors demonstrate that in patients with sarcoidosis LVEF was closely related to TMPS and GMS, and LVEF reflected the progression of sarcoid heart disease and can be considered a reliable indicator of cardiac function. Patients with sarcoidosis with TMPS abnormality and positive GMS should be thought to have myocardial sarcoidosis and their cardiac functions can be assessed by ECG-gated radionuclide ventriculography, while the remaining patients should be examined with TMPS and GMS periodically for detection of myocardial involvement.