Search

Background: We have developed a system to monitor, simultaneously and continuously, ambulatory SaO2 measured using a pulse-oximeter and ECG data for 24 hours. Methods: The ambulatory SaO2-ECG monitoring system consisted of a portable monitoring device (SM50) with two channels for ECG data and one channel for SaO2 data input; a sensor for SaO2 recording; and a pulse-oximeter. An ambulatory monitoring analyzer was used. The SaO2 report from the present analyzer included two types of data (i.e., a profile of heart rate [HR], pulse rate [PR], and SaO2 value per min), and a trend graph of HR, arrhythmia, ST level and slope, PR, and SaO2 per minute. We also designed and produced an analytical program to automatically remove noise errors relating to the SaO2 measurement. Results: Using this system, we performed a clinical study on ten healthy volunteers (Group N) and seven patients with chronic pulmonary diseases (Group CPD) to evaluate the usefulness of the system as a diagnostic means for respiratory failure and arrhythmia. Group N showed a stable value of 90% or over in SaO2 during the 24-hour monitoring while Group CPD showed values under 90% SaO2 in all patients at rest during the night or after a 15-minute walk. Transient atrial tachycardia (TAT) was observed in 3 of 7 CPD patients, and each episode was preceded by a decrease of SaO2. The occurrence of a single or double ventricular extrasystole was high in Group CPD compared with Group N (1.21 ± 0.89 vs 0.6%± 0.3%, P < 0.05), its occurrence was not associated with a decrease in SaO2. Conclusions: In outpatients, especially patients who are taken care of at home, the present system will certainly contribute greatly to the diagnosis of respiratory failure and arrhythmia as well as to evaluate the effects on these diseases of therapy. In addition it is suggested that in CPD, patients’hypoxemia may induce TAT.

We characterized the influence of the size of the left ventricular (LV) chamber (LV diastolic diameter, LVDD) and LV end-diastolic pressure (LVEDP) on left atrial active stroke index (LAASI) in patients with old myocardial infarction (OMI) (n = 118) and controls (n = 25). Patients with OMI were classified into four groups according to the grade of LVDD (or = 55 or55 mm) and LVEDP (or = 18 or18 mmHg). LAASI was determined by multiplying the LV stroke index by the fraction of left atrial active contraction of the velocity-time integral on the pulsed-wave Doppler echocardiogram. LAASI in the "LVDDor = 55LVEDPor = 18" group was less than that in the groups with normal LVEDP. LAASI did not differ among the normal LV dimension groups. The combination of LV enlargement and high LVEDP was related to the decrease in LAASI in patients with OMI.

The aim of this study was to determine whether myocardial injury resulting from temporary ischemia followed by reperfusion can be measured by assaying sulfhydryl groups in the affected tissue of a rat model of myocardial infarction. We studied 3 groups: a control group (n = 6), which underwent surgery without left coronary artery (LCA) ligation; group NoR (n = 9), in which the LCA was ligated for 3 h; and group I + R (n = 7), in which 30 min LCA ligation was followed by 3 h reperfusion. The sulfhydryl group content of myocardial tissue was assayed by measuring the fluorescence produced by incubating heart sections with N-(7-dimethylamino-4-methyl-3-coumarinyl) maleimide (DACM), which binds sulfhydryl groups. The fluorescence intensity (FI) of normal and infarcted myocardium was quantified by our computerized system of microscopic fluorophotometry. Indices such as sulfhydryl group content, the size of the low-FI area [% AREA(lower FI)] and the relative decrease in FI [%FI(decrease)]) in the infarct zone were calculated. Both %AREA(lower FI) and %FI(decrease) were significantly higher in the infarcted zone of animals in NoR and I + R groups than in control animals. Both indices were higher in infarct tissue from animals in the I + R group than in the NoR group. These changes suggest that sulfhydryl group content is significantly reduced in tissue that has been subjected to ischemia-reperfusion. Microscopic fluorophotometry, as defined by DACM staining of myocardial tissue, may help to delineate areas of myocardial reperfusion injury.

To establish an early diagnosis and have a quantitative estimation of congestion or edema, pulmonary CT scans were performed to detect the increase of regional lung water volume of patients with congestive heart failure. CT scanning of the upper, middle, and lower lung fields at maximum inspiration and hemodynamic analysis to ensure a hemodynamically chronic stable condition after the heart failure therapy for 5 weeks by cardiac catheterization within 2 weeks before CT scanning were performed in 10 normal subjects and 25 patients with left-sided heart failure. Patients were divided into two groups according to the presence or absence of pulmonary congestion or edema on chest radiographs, and the mean pulmonary wedge pressure (mPWP). The pulmonary congestion group (14 patients) had pulmonary congestion or edema, and mPWP was greater than 13 mm Hg despite the heart failure therapy. The nonpulmonary congestion group (11 patients) had no pulmonary congestion or edema, and mPWP was lower than 10 mm Hg. Histograms of pulmonary CT numbers were graphed to a set region of interest (ROI) on transverse CT images in all subjects; then changes of pulmonary CT numbers when pulmonary congestion or edema occurred were estimated from those histograms. We found that when severe pulmonary congestion or edema occurred in 6 patients with severe left heart failure, the pulmonary CT numbers within the ROI rapidly increased from -650 to -750 Hounsfield units (HU). We defined the amount ratio between the pixels (pixel counts between -650 and -750 HU within these R0Is) and the pixels (pixel counts between -300 and -950 HU) of the CT number (which were all pixels composing these R0Is) x100(%) as "%PXL." %PXL showed a linear correlation with mPWP. Compared with the %PXL in the normal group, the %PXL in the pulmonary congestion group was significantly higher than that in the normal group (p

急性心不全の治療方針についてはvital signに配慮しつつ血行動態異常の改善をはかることを原則とする.一方慢性心不全の治療においては問題が複雑であり,各目標が互いに矛盾するので必ずしも十分なコンセンサスが得られていない.症状の改善,活動能力の増大を主な内容とするQOLの向上に努めるとともに長期生命予後にも配慮することが現実的な方針ではないだろうか.その実現の手段として薬物動員の順序原則について言及する.

Objective: The clinical use of skeletal muscle cardiomyoplasty is limited because of its inadequate haemodynamic benefits. To facilitate experimental and clinical efforts to improve the efficacy of this technique, a mathematical model was proposed and its validity was tested in acute experiments. Methods: The model was based on the assumption that the skeletal muscle wrapped around the heart behaves as a time varying elastance that is connected in series with another time varying elastance representing the native heart. From this model two predictions were made: (1) Skeletal muscle augments the contractility of the heart by increasing the slope (Ees) of the end systolic pressure-volume relation; (2) time varying elastance of the skeletal muscle chamber (Es(t)) can be estimated from that of the assisted heart. These predictions were examined in experiments. In nine anaesthetised, open chest dogs, preconditioned latissimus dorsi muscle was transposed to wrap the heart. Left ventricular pressure (catheter tipped micromanometer), and volume (conductance catheter) were measured while reducing the preload by vena caval occlusion to evaluate Ees with 1:2 (stimu1ation:heart beat ratio) stimulation of the skeletal muscle. Results: With the stimulation of latissimus muscle, the end systolic pressure-volume relation was linear and Ees increased from 8.6(SEM 2.4) to 11.9(SEM 3.4) mm Hg·ml−1. Estimated Es(t) reflected the stimulation pattern and could account for the mechanism of the cardiac assistance. Conclusions: Skeletal muscle cardiomyoplasty improved the haemodynamic variable (Ees) as predicted by a mathematical model. Cardiovascular Research 1993; 27 :997-1003

Objective: The aim was to determine the slope (EES) of the left ventricular end systolic pressure-volume line (ESPVL) without altering preload or afterload in conscious dogs. Methods: Dogs (n=10) were instrumented to determine left ventricular volume from ultrasonic left ventricular internal dimensions, and to measure left ventricular pressure using a micromanometer. Studies were performed one to two weeks after instrumentation while the animals were conscious. ESPVL was determined from variably loaded left ventricular pressure-volume (P-V) loops generated by the vena caval occlusion. Contractile state was increased by intravenous dobutamine (8 μg·kg−1·min−1) and decreased by intravenous verapamil (10 mg) given after autonomic blockade. From a single normally ejecting beat, we calculated EES-single beat (mm Hg·ml−1) as peak isovolumetric pressure (Pmax) minus end systolic pressure divided by stroke volume. Sunagawa's technique was used to estimate Pmax by fitting the pressure during the isovolumetric contraction and relaxation as: P(t)=l/2 × Piso[1-cos(ωt+c)]+LVEDP, where Piso=peak isovolumetric developed pressure, LVEDP=left ventricular end diastolic pressure, c=constant accounting for variations in phase angle, and ω=2 π/T in which T is duration of contraction. Results: After dobutamine, EES increased, from 8.9(SEM 0.8) to 12.5(1.0) mm Hg·ml−1 (p < 0.05), and Epg-single beat increased from 9.1(0.9) to 12.0(1.4) mm Hg·ml−1 (p < 0.05). Conversely, after verapamil, EES decreased, from 11.1(1.2) to 6.3(1.1) mm Hg·ml−1, (p < 0.05), and EES-single beat also decreased, from 9.6(1.0) to 7.3(1.2) mm Hg·ml−1, (p < 0.05). Conclusions: EES calculated from one beat is similar to EES determined from variably loaded left ventricular loops and responds appropriately to inotropic stimulation. This technique provides a reasonable method to calculate EES from left ventricular pressure and stroke volume without altering preload or afterload. Cardiovascular Research 1993; 27 :868-873

We measured the relative sliding velocity of cardiomyopathic hamster cardiac myosin on actin cables by using an in vitro motility assay system. We also investigated the relationship between the velocity and both myosin isozyme content and ATPase activity. Cardiac myosin was obtained from cardiomyopathic hamsters (BIO 14.6; B) aged 3, 6, 9, and 18 months and age-matched controls (F1B; F). Long well-organized actin cables of an alga, Nitellopsis, were used for the motility assay. Small latex beads (2 microns in diameter) were coated with purified cardiac myosin. When myosin-coated beads were introduced into an algal cell in the presence of Mg-ATP, myosin interacted with actin and dragged the beads. Active movement of the beads along the actin cables was observed under a photomicroscope and the velocity was measured. The velocity was significantly lower in B than in F for each age group (0.47 vs. 0.71 microns/s at the age of 3 months, p0.05; 0.44 vs. 0.88 microns/s at 6 months, p0.01; 0.44 vs. 0.67 microns/s at 9 months, p0.01; 0.35 vs. 0.52 microns/s at 18 months, p0.05). Both Ca(2+)-activated ATPase activity and the percentage of alpha-myosin heavy chain were also lower in B than in F for each age group. When examined for individual specimens, there was a positive correlation between the velocity and both myosin Ca(2+)-activated ATPase activity (r = 0.84) and percentage of alpha-myosin heavy chain (r = 0.83). These data points of both control and cardiomyopathic hamsters were distributed near the regression line obtained from control and thyroxine-treated rabbits reported previously. The present results indicate that the difference in mechanical properties between control and cardiomyopathic cardiac myosin is attributed to isozyme redistribution and not to a qualitative change in each myosin molecule.

To elucidate mechanisms of adaptation and maladaptation in heart failure. abnormalities of left ventricular function and their relationships to myocardial contractile protein were studied in the Syrian hamster Bio 14.6. Left ventricular and heart weights were both increased in 20-week-old cardiomyopathic hamsters, indicating cardiac hypertrophy as a compensatory mechanism to the disease process of cardiomyopathy. However further increase in the left ventricular weight was not observed in older (40-week-old) cardiomyopathic hamsters. On the other hand left ventricular volume and volume/mass ratio were increased progressively. Correspondingly, V3 type myosin was increased and myosin sliding velocity was decreased. Left ventricular function of cardiomyopathic hamsters evaluated using an isovolumically beating perfused heart preparation was depressed, and this functional impairment was also progressive. Chronic administration of metoprolol, a β-blocking agent, induced further increase in left ventricular volume and mass without changing left ventricular function and myosin isozyme pattern. Thus In cardiomyopathic hamsters, left ventricular function progressively deteriorates in spite of a variety of adaptive mechanisms, and remodeling occurs. β-blocking agents may modify this process.

We assessed alpha-adrenoceptor-mediated inotropism in comparison with beta-adrenoceptor-mediated inotropism in whole left ventricle. We used an isolated perfused isovolumic rabbit heart preparation, which enables one to assess contractility and time course of contraction as well as energetic efficiency. Left ventricular pressure (LVP) and volume were measured with an intraventricular fluid-filled balloon. Myocardial oxygen consumption was assessed from the oxygen tension of coronary effluent. Both isoproterenol (n = 7) and phenylephrine (n = 7) increased LV developed pressure (LVDP). Isoproterenol shortened the time to peak pressure (Tmax) from 171 +/- 6 to 142 +/- 7 ms (p less than 0.01) and the time constant of LV pressure decay (TBF) from 44.8 +/- 2.7 to 32.8 +/- 1.9 ms (p less than 0.01). In contrast, phenylephrine slightly but significantly prolonged Tmax from 178 +/- 4 to 184 +/- 4 (p less than 0.05) and did not alter TBF. Both isoproterenol and phenylephrine increased O2 consumption, whereas only phenylephrine increased the force-time integral from 14.0 +/- 1.5 to 17.2 +/- 2.1 g.s (p less than 0.01). These results confirmed in the whole heart preparation that alpha- and beta-adrenoceptor-mediated inotropisms had qualitatively different effects on the time course of contraction and energetic efficiency.

An animal experimental model which stimulates human effort angina, especially in terms of diastolic abnormalities, was developed using isovolumically beating perfused rat hearts. Using this model, we studied the effects of nifedipine, a Ca2+ channel blocker, on diastolic properties during pacing-induced ischemia. When the preload of the left ventricle was set at a low level, low-flow ischemia (coronary perfusion pressure of 40 mmHg) plus tachycardia (480 beats/min for 4 min) did not induce an increase in left ventricular end-diastolic pressure (LVEDP). However, with a high preload, low-flow ischemia plus pacing tachycardia induced an increase in LVEDP of 8.4 +/- 5.4 mmHg (p less than 0.01) and a prolongation of the time constant of ventricular pressure decline (6.8 +/- 4.6 msec, p less than 0.05) immediately after pacing tachycardia. Pretreatment with nifedipine (3 x 10(-8) M) prevented the rise in LVEDP induced by pacing tachycardia. Thus, in isolated perfused hearts, diastolic abnormalities similar to those seen in angina pectoris were obtained by low-flow ischemia plus pacing tachycardia. The response to nifedipine suggested that an alteration of Ca2+ movement may play an important role in the increase in left ventricular stiffness under these conditions.

Both myocardial contractility and contraction duration were assessed load-independently in isolated hypertrophic and control rat hearts. Hemodynamic parameters for isolated isovolumically contracting hearts were compared for 7 Wistar rats with DOCA-salt induced hypertrophy (LVH) and 7 controls. Loads were altered by changing the volume of an intraventricular balloon. Myocardial contractility was assessed in terms of the shortening-afterload (Sm-sigma aft), and the ejection fraction-afterload (EF-sigma aft) relations at common preloads, based upon the systolic myocardial stiffness concept. Indices of contraction duration (time to maximum stiffness, pressure time integral divided by peak pressure and the time required for left ventricular (LV) peak pressure to be reduced by a half) were prolonged in LVH. Multiple regression analyses indicated that the degree of hypertrophy was an independent determinant of the contraction duration. The Sm-sigma aft and EF-sigma aft relations at common preloads demonstrated normal contractility in the LVH group. The time constant of the fall in LV pressure and the diastolic myocardial stiffness remained normal in the LVH group. Thus, we introduced the new approach to load-independently assess both the myocardial contractility and the contraction duration in a whole ventricle. A prolonged contraction duration in the presence of normal myocardial contractility was observed in a ventricle with moderate pressure-overload hypertrophy.

Coenzyme Q10 (10 mg/kg/day) or digoxin (2 micrograms/kg/day) was given orally to cardiomyopathic hamsters (BIO 14.6) for 8 weeks from 12 weeks of age. The left ventricular weight per gram of body weight (mg/g) was lower (p less than 0.01) in the coenzyme Q10 group (3.09 +/- 0.13) than in the digoxin (3.32 +/- 0.20) and control (3.44 +/- 0.14) groups. Left ventricular function was evaluated in isovolumically beating hearts. Left ventricular developed pressure (63 +/- 5 vs. 54 +/- 10 mmHg, p less than 0.05), -dP/dt (1385 +/- 100 vs. 1211 +/- 136 mmHg/sec, p less than 0.05), and -dP/dt (1068 +/- 126 vs. 896 +/- 141 mmHg/sec, p less than 0.05) were greater in the coenzyme Q10 than in the control group. The time constant of left ventricular relaxation was shorter in the coenzyme Q10 group than in the control group (25 +/- 3 vs. 28 +/- 3 msec, p less than 0.05). By contrast, in the digoxin group, the indices of left ventricular function did not differ from the control group. These results suggest that coenzyme Q10, but not digoxin, attenuated disease progression and preserved left ventricular function in cardiomyopathic hamsters.

By using a helper-free and replication-defective recombinant retrovirus encoding the SV40 early antigens (MV40), we have established continuous macrophage (M phi) lines. All of the lines were nonproducer M phi's with differentiated M phi functions such as phagocytosis, cytotoxicity, and IL-1 and TNF production. To determine the effects of several cytokines on growth of mature M phi's, the responsiveness of these established M phi lines to various cytokines was investigated in methylcellulose culture. Their response patterns to several cytokines alone and in combination were different, implying that there might be mature M phi subpopulations with distinct growth profiles regulated by several cytokines. On the other hand, all of the lines efficiently yielded a number of colonies in response to interleukin-4 (IL-4) alone. Moreover, IL-4 cooperated with interleukin-3 (IL-3) to enhance colony formation of all the lines. A similarly synergistic effect was observed in combination of IL-4 and macrophage-colony stimulating factor (M-CSF) in almost all the lines. Similar results were obtained with colony formation of fresh thioglycolate-induced M phi's. These observations suggested that IL-4 was involved in growth of mature M phi's. Our present results suggest that the helper-free and replication-defective MV40 is of use to obtain continuous and functional cell lines from primary M phi's.

Changes in parameters of left ventricular (LV) diastolic filling flow obtained with Doppler echocardiography during the lower body positive and negative pressure method were analyzed in 15 patients (12 with coronary artery disease and 3 with dilated cardiomyopathy). Lower body pressure was altered at 5 steps (+20, +10, 0, -20 and -40 mm Hg vs atmospheric pressure). Pulmonary capillary wedge pressure measured with a balloon-tipped catheter was changed proportionally with lower body pressure during the procedures (p less than 0.01). Mean systemic arterial pressure was changed slightly during lower body positive pressure and negative pressure of -40 mm Hg. Heart rate was almost unchanged except at lower body pressure of -40 mm Hg. The peak velocity of LV early diastolic filling flow was changed with pulmonary capillary wedge pressure in an almost parallel fashion during the procedures (p less than 0.01). The peak velocity of LV late diastolic filling flow showed smaller changes than that of early diastolic filling flow. Changes in pulmonary capillary wedge pressure correlated positively with changes in the peak velocity of LV early diastolic filling flow (r = 0.759, p less than 0.01), but not with changes in the peak velocity of LV late diastolic filling flow (r = 0.039, not significant) during lower body negative pressure of -20 mm Hg. These data suggest that left atrial pressure is one of the important determinants of LV early diastolic filling flow in this acute clinical setting and that LV late diastolic filling flow is less sensitive to changes in left atrial pressure than LV early diastolic filling flow.

The role of leukocytes (WBCs) and platelets (PLTs) in the pulmonary circulation may be important in the development of monocrotaline (MCT)-induced pulmonary hypertension in rats. We investigated the changes in WBCs and PLTs in the pulmonary microvasculature during the development of chronic pulmonary hypertension in MCT rats by real-time confocal scanning laser microscopy. The number of WBCs sequestered in the pulmonary microvasculature increased significantly from day 7 after MCT injection, but no further increase occurred from days 14-28. The number of PLTs sequestered in the pulmonary microvasculature increased significantly from day 7 after MCT injection, and reached a peak on day 14. However, the number of PLTs sequestered on days 21 and 28 after MCT injection was significantly lower than on day 14. These findings suggest that PLTs mainly contribute to the initial and middle stages of the development of MCT-induced pulmonary hypertension in rats, while WBCs mainly contribute to the middle and late stages.

Coronary angiographic and risk factor (RF) characteristics were analyzed in 133 Japanese patients with ischemic heart disease (IHD) who were less than 40 years old and who had undergone coronary angiography (CAG) during the past 10 years at six university hospitals in the Tokyo area. We compared the coronary angiographic characteristics of the subject group with those of 216 controls with coronary sclerosis detected by CAG who were more than 40 years old (older control group) and the RF characteristics with those of 133 sex- and age-matched volunteers (younger control group). Sixty seven percent of the subjects (89 cases) were diagnosed as having myocardial infarction (MI) and 33% (44 cases) had angina pectoris (AP). Coronary artery disorders in this group consisted of 103 (77%) cases of coronary sclerosis, 20 (15%) cases of coronary spasm and 10 (8%) cases of miscellaneous diseases, eg, possible vasculitis with connective tissue disease, congenital anomalies, etc. The incidences of significant (> or = 75%) sclerotic narrowing in 0 vessels (31%) and 1 vessel (49%) in the subject group were significantly (p < 0.01) higher than those in the older control group, while the incidence of multivessel disease was significantly (p < 0.05) less in the subject group than in the older control group. The incidences of the following coronary risk factors were significantly (p < 0.05) higher in the subjects than in the younger controls: smoking (83% vs 35%), hypercholesteremia (44% vs 10%), obesity (31% vs 9%), hypertension (29% vs 3%), familial IHD (28% vs 7%) and diabetes mellitus (19% vs 2%). Thus, zero- or single-vessel disease predominated in the younger subject group and the prevalence of coronary risk factors was significantly higher in the subject.

An increase in left ventricular diastolic pressure relative to volume during spontaneous attacks of angina pectoris [1] and angina attacks provoked by exercise [2] or pacing tachycardia [3–5] has been reported by many investigators in patients with coronary artery disease. This decreased left ventricular diastolic distensibility is usually accompanied by a decrease in the rate of left ventricular relaxation. Similar changes in diastolic properties have been observed in open- chest dogs with severe coronary stenoses and super-imposed pacing tachycardia [6,7]. Several possible mechanisms producing such changes have been proposed [8], and one of the most likely of these is an alteration in intrinsic myocardial properties due to ischemia-induced calcium overload and/or decreased availability of ATP. However, investigations using open-chest dogs could not completely exclude other mechanisms, such as extrinsic diastolic compression by the right ventricle, or dyssynchrony between the ischemic and normal myocardium.

The effects of pituitary adenylate cyclase activating polypeptide (PACAP) on the cardiovascular system were examined. When PACAP-38 (270 or 420 pmol/kg body weight) was administered intravenously to the anesthetized dogs, both mean arterial pressure and left ventricular systolic pressure increased within 2 min after a temporal depression. Pulmonary arterial systolic pressure increased promptly. These hemodynamic values and heart rates (HR) 5 min after injection were significantly higher than the corresponding values in physiological saline injected dogs, and some effects were still sustained over 15 min. Cardiac output and stroke volume also increased and the values at 5 min were significantly higher than those in controls. The high dose of PACAP-38 (420 pmol/kg) evoked greater responses than those induced by the low dose (270 pmol/kg). Plasma adrenaline, but neither noradrenaline nor dopamine concentration significantly increased 15 min after injection of 420 pmol/kg PACAP-38. Moreover, PACAP-38 clearly stimulated cyclic AMP production in rat cardiac myocytes with EC 50 of 1.5·10 −9 M and plasma cAMP levels significantly and dose-dependently increased in dogs 5 min after administration. These results first demonstrated that PACAP has inotropic and chronotropic actions on the heart possibly by a direct stimulation of adenylate cyclase in cardiac myocytes and also that the cardiovascular functions may be possibly modified by an evoked adrenaline secretion in vivo.

Forearm venous distensibility was studied in 24 patients with congestive heart failure using strain gauge arch plethysmography. The venous distensibility was assessed as a venous stiffness constant by fitting a forearm venous pressure-volume curve to an exponential function. Venous pressure-volume curves were clearly separated among New York Heart Association (NYHA) classes with leftward shift and increased slopes correlating with increased NYHA grade. The venous stiffness constant was elevated significantly with increased severity of symptoms (NYHA classes: P < 0.02) and hemodynamic parameters (pulmonary vascular resistance: r = 0.73, P < 0.02; pulmonary capillary wedge pressure: r = 0.54, P < 0.02; cardiac index: r = 0.45, P < 0.03; systemic vascular resistance: r = 0.45, P < 0.03). While the expected effect of nitroglycerin on the venous stiffness constant was demonstrated in this study, the effect of alpha human atrial natriuretic polypeptide proved minimal.

The active sliding of cardiac myosin on actin cables was studied using an in vitro movement assay. Cardiac myosin prepared from either adult rabbit or rat hearts was mixed with small latex beads to coat them. Actin cables were obtained from the internodal cells of green algae, Characeae. When the myosin-coated beads suspended in physiological buffer were introduced into the internodal cells, the myosin started to interact with the actin causing the beads to move. The sliding movement of the beads was observed under microscopy and the sliding velocity measured. The observed movement was smooth and the velocity was constant over a long distance. The movement was physiological in nature: a) it was ATP-dependent, but above a certain level of ATP, the velocity was constant; b) the velocity was maximum at pH 7.0, and decreased in both acidic and alkaline conditions. The average sliding velocity of cardiac myosin obtained from rabbit ventricles (0.31 +/- 0.11 micron/s) was slower than that from rat ventricles (1.04 +/- 0.26 micron/s) reflecting the lower ATPase activity of rabbit cardiac myosin. This assay system is considered to be a useful tool linking biochemistry and physiology at the molecular level.

We studied the effect of thyroid status on thyrotropin-releasing hormone receptor (TRH-R) mRNA levels both in vivo and in vitro (GH3 cells) using a cloned rat TRH-R cDNA by RT-PCR. Experimental hypothyroid rats were produced by total thyroidectomy and were then killed 7 days after the operation. TRH receptor binding in the anterior pituitary and serum TSH level were elevated approximately 2-fold and 8-fold, respectively, in 7 day thyroidectomized rats. TRH-R mRNA levels in hypothyroid rats were also increased significantly compared with those of normal rats. In GH3 cells, however, no significant change of TRH-R mRNA level was observed between cultures treated with triiodothyronine (T3, 10 −9 and 10 −7 M) and the untreated group. The present data indicate that 1) the in vivo effects of thyroid status on TRH-R mRNA levels differ from the in vitro one, and that 2) the down regulation ofTTRH-R binding by thyroid hormone in GH3 cells may be mediated by translational or post-translational mechanisms.

We examined the structure of the TSH receptor gene in various thyroid disorders by a restriction fragment length polymorphism (RFLP) study with a cloned human TSH receptor cDNA as a probe. Southern blot analysis of DNAs in peripheral white blood cells obtained from normal individuals revealed a single band in each of several restriction enzyme digestions, indicating that the TSH receptor gene is a single copy gene in the human genome. Although RFLPs were not detected in peripheral blood cells and thyroid tissues in patients with Graves' disease, thyroid carcinomas, or subacute thyroiditis, significant RFLPs were found in 2 of 6 patients with adenoma in all restriction enzyme digestions examined. Moreover, these RFLPs were heterozygous and adenoma specific, and these additional bands in adenoma were amplified in both cases. We conclude that there are no major abnormalities in the structure of the TSH receptor gene in patients with Graves' disease, thyroid carcinoma, or subacute thyroiditis, although there may be a possibility of point mutations, small insertions, or deletions that cannot be detected by RFLP studies, and that there are large insertions or deletions in the region, including the TSH receptor gene, in some patients with thyroid adenoma.

In this brief review the progress in the treatment of chronic heart failure is discussed from standpoint of understanding of mechanisms of heart failure.Nobody would disagree that an effective treatment must be based on thorough understanding of disease mechanisms. In reality,however,it is not the case in heart failure.We are treating heart failure without knowing its exact mechanisms.In this area,con¬versely,development of treatment has stimulated and accelerated stud¬ies on the mechanisms of disease.So in this article how each drug was introduced and how progress in understanding of mechanisms follo- ed will be presented.

We examined the effects of four kinds of intravascular contrast agents (amidtrizoic acid, iohexol, iopamidol, and ioxaglic acid) on [Ca2+]i transients (indo-1 fluorescence) and cell contraction (video motion analyzer), using cultured chick embryo ventricular myocytes. Exposure of ventricular myocytes to amidtrizoic acid (a conventional contrast agent) reduced the [Ca2+]i transients and the sensitivity of the contractile elements to [Ca2+]i. Ioxaglic acid (a low osmotic contrast agent) also reduced the [Ca2+]i transients, but did not significantly change the sensitivity of the contractile elements to [Ca2+]i. Neither iohexol nor iopamidol (nonionic contrast agents) reduced the [Ca2+]i transients, but both significantly decreased the sensitivity of the contractile elements to [Ca2+]i. A marked negative inotropic effect of amidtrizoic acid was caused by both calcium binding and hypertonicity. The less marked depression of contractility produced by ioxaglic acid is possibly the result of calcium binding, but is not caused by hypertonicity. The negative inotropism produced by nonionic contrast agents (iohexol and iopamidol) was due to hypertonicity, but not due to alterations in the [Ca2+]i transients. Exposure of ventricular myocytes to nonionic contrast agents (iohexol and iopamidol) slowed decay in the [Ca2+]i transients with increased end-diastolic [Ca2+]i. After washing out the nonionic contrast agents, these parameters returned to control levels. On the other hand, exposure to amidtrizoic acid decreased end-diastolic [Ca2+]i without changing decay time in the [Ca2+]i transients. After washing out amidtrizoic acid, there was a prolongation of half decay time in [Ca2+]i transients with a significant increase in end-diastolic [Ca2+]i and cell position. Diastolic dysfunction just after washout of amidtrizoic acid was possibly caused by an increase in [Na+]i due to sodium influx during exposure to the contrast agent.

Interleukin 2 (IL-2)-dependent granular T lymphocyte (GTL) lines derived from murine spleen were shown to express a Ly-5 antigen with the so-called 'B220-epitope' recognized by 6B2 mAbs, which were normally exhibited on B-lineage cells. Immunoprecipitation analysis revealed that the Ly-5 isoform on GTL lines represented the highest-molecular-weight Ly-5 so far described (260 kd), distinct from the B220 isoform on a pre-B cell line (240 kd). The size difference between them was also evident after the endoglycosidase treatment (210 versus 190 kd), strongly suggesting that these Ly-5 isoforms had core proteins of distinct size. Sequential immunoprecipitation by 6B2 and 14.8 mAbs further indicated that the 260 kd Ly-5 on GTL lines predominantly expressed '6B2 epitope' while '14.8 epitope' dominated in the B220 (240 kd) on a pre-B cell line. Northern blot analysis of the Ly-5 transcripts using probes for the known alternative exons failed to show any evidence for mRNA of the 260 kd Ly-5 distinct from that of B220. Polymerase chain reaction analysis, however, suggested that the 260 kd isoform mRNA might be transcribed from a distinct promoter with a yet undefined exon(s). The 6B2+ Ly-5 isoform was hardly detected on normal splenic T cells, but was shown to be induced rapidly on the majority of T cells following IL-2 stimulation in vitro, indicating that this particular Ly-5 isoform behaved as an 'activation antigen' on T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

We analyzed the relationships among parameters of left ventricular (LV) early diastolic filling flow (EDF) obtained with pulsed Doppler echocardiography, mean pulmonary wedge pressure (PCWP) and the time constant of LV pressure fall calculated by either Weiss' (Tw) or Thompson's (Tb) method. PCWP correlated with the peak velocity (R) (r = 0.537, p less than 0.05), acceleration (Ac) (r = 0.545, p less than 0.05) and deceleration (Dc) (r = 0.606, p less than 0.01) of LVEDF. In contrast, Tb correlated only with the time to the peak of LVEDF (TPF) (r = 0.487, p less than 0.05), and Tw did not correlate with the Doppler-derived indices significantly. After correcting for the effect of PCWP, significant partial correlations between R and Tw (r = -0.535, p less than 0.05), and between Ac and both Tw (r = -0.606, p less than 0.01) and Tb (r = -0.569, p less than 0.05) were found. Dc did not correlate with Tw or Tb. These results suggest that the level of left atrial pressure may mask the relationship between parameters of LVEDF and LV relaxation, and that the relations among these variables vary with individual indices of LVEDF.

To study the effects of atrial natriuretic peptide (ANP) on body fluid volume regulation, we estimated the changes in intra- and extravascular fluid volume by measuring hematocrit (Hct), plasma protein concentration and water balance, and the changes in intra- and extracellular fluid volume by the electrical impedance method during intravenous infusion of ANP. We did two studies, as follows: ANP was infused into 18 patients with essential hypertension, 29 with renal parenchymal hypertension and 15 normotensives at 0.025 microgram/kg/min for 40 min. Both hypertensive groups showed greater natriuretic responses to ANP than normotensives. ANP infusion into essential hypertensive patients increased the urinary excretion of water by 125%, Na by 205%, Hct by 4.2% and plasma total protein (TP) by 5.2% (each P less than .001). In 9 patients (1 with renal hypertension and 8 normotensives) who did not show a natriuretic response (-2.1%), the infusion of ANP also significantly increased Hct (3.8%) and plasma TP (3.1%, each P less than .01). The electrical impedance method was applied to 12 subjects to simultaneously detect the intracellular (Ri) and extracellular resistivities (Re), of which reciprocals reflect the fluid volume in the extra- and intracellular spaces, respectively. ANP infusion increased Re in all subjects (3.96 +/- 0.16 [SE] v 4.03 +/- 0.16 omega.m, P less than .05), but decreased Ri in 7. Changes in urinary Na excretion correlated positively with those in both Re (r = 0.62, P less than .05) and Ri (r = 0.75, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute hemodynamic changes induced by two beta-blocking agents, bunitrolol and propranolol, in patients with ischemic heart disease were studied. Besides possessing negative chronotropic and inotropic effects which were demonstrated by decreased heart rate (HR), cardiac index (CI) and double product (DP) of the heart, propranolol significantly increased systemic vascular resistance (SVR, 12%, p less than 0.05) and the time constant of left ventricular (LV) isovolumic pressure fall (T, 10%, p less than 0.01). With bunitrolol, no significant changes were observed in indexes reflecting chronotropic and inotropic states of the heart, and CI and DP were essentially unchanged. Only LV systolic pressure (-5%, p less than 0.01), LV end-diastolic pressure (EDP, -17%, p less than 0.01) and T (-10%, p less than 0.05) decreased significantly. Systemic vascular resistance (SVR) decreased, though insignificantly. Myocardial oxygen supply-demand balance in the resting state was not improved by propranolol as evidenced by the fact that CI decreased in proportion to the decline in DP. In contrast, ischemia at rest was apparently improved by bunitrolol because LV wall stress decreased due to the reduction in LV volume which was suggested by the decline in LV systolic pressure and LVEDP while CI remained constant. Improvement of the time constant T might be strong evidence of relief from ischemia. Bunitrolol might be effective even in patients with overt heart failure, especially that due to ischemic heart disease because of its lack of negative inotropic action and its ameliorating effect on ischemia at rest.

The cDNA for the murine granulocyte/macrophage colony-stimulating factor (GM-CSF) was cloned from a cDNA library obtained from a murine T cell line, IH5.5, by using two synthetic probes that encoded two parts of the GM-CSF from murine lung. The cDNA inserted into the plasmid vector pcDV1 was transfected into monkey COS-1 cells and the conditioned medium was used to investigate the hemopoietic activities of the resultant product, recombinant GM-CSF (rGM-CSF), by means of various colony assays. rGM-CSF stimulated only neutrophil/macrophage colonies in the cultures of murine normal bone marrow and fetal liver cells. No other colony stimulating activities (CSA) were seen in the preparation including burst-promoting activity, eosinophil-CSA, megakaryocyte-CSA and mast cell-CSA. rGM-CSF could not support colony formation of 5-fluorouracil-treated mouse spleen cells, in which only the primitive population of stem cells survived. However, after culture of these cells with PWM-spleen cell-conditioned medium (PWM-SCM), the colonies consisting of blast cells were formed. These blast cells could now be induced to form neutrophil/macrophage colonies in the presence of rGM-CSF. Pure neutrophil colonies, pure macrophage colonies, as well as mixed neutrophil/macrophage colonies, were formed from these single blast cells in the presence of rGM-CSF by micromanipulation. rGM-CSF did not act on pluripotent hemopoietic stem cells, but did act directly and selectively on neutrophil/macrophage progenitors. Moreover, striking heterogeneities were noted in the size of the colonies and the proportion of components. GM-CSF is, therefore, considered to play a noninstructive role in the differentiation of the GM pathway.

To elucidate the possibility of grading the severity of congestive heart failure by using venous characteristics, we constructed venous pressure-volume curves (PVR) and calculated venous stiffness constants (K). In addition, effects of vasoactive drugs on venous distensibility were studied. A venous pressure-volume curve could be fit well by an exponential curve (r = 0.98 +/- 0.01). The PVR was shifted to the left with an increase in the clinical severity of congestive heart failure. The exponent of these curves, K, increased as the PVR was shifted to the left. K correlated with heart rate (r = 0.52, p less than 0.01), right atrial pressure (r = 0.54, p less than 0.02) and mean pulmonary arterial pressure (r = 0.47, p less than 0.04). Nitroglycerin and amrinone dilated veins and decreased K by 19.6 +/- 6.9% (p less than 0.03) and 14.0 +/- 4.3% (p less than 0.02), respectively. Changes in K (delta K) during the nitroglycerin and amrinone infusions correlated closely with the baseline K (delta K = -0.41 K + 0.22, r = 0.92, p less than 0.01). Therefore, the venodilating effects of these drugs were greater in patients with more severe congestive heart failure. The venous stiffness constant could be useful to grade the severity of congestive heart failure.

Two expression plasmids (pSVIFN gamma/BPV97 and pSVIFN gamma/AdDHFR) for constitutive production of human interferon-gamma (HuIFN-gamma) were constructed and introduced into the two different mammalian cell lines, mouse C127 cells and Chinese hamster ovary (CHO) cells. Genetically engineered C127 and CHO cells grew on microcarriers having high productivity of HuIFN-gammas for at least six months. Isoelectric focusing patterns and molecular weight analyses suggest that C127- and CHO-HuIFN-gammas are glycoproteins and that both HuIFN-gammas have different molecular structures. The development of a microcarrier culture system for genetically engineered mammalian cells has enabled us to prepare glycosylated HuIFN-gammas on a large scale.