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Endotoxins, or lipopolysaccharides (LPS), are potent immunostimulatory molecules of critical concern in bacterial recombinant protein expression systems. The gram-negative bacterium Acinetobacter baumannii exhibits an interesting and unique phenotype characterized by the complete loss of LPS. In this study, we developed a novel system for producing recombinant proteins completely devoid of endotoxin contamination using LPS-deficient A. baumannii . We purified endotoxin-free functional green fluorescent protein, which reduced endotoxin contamination by approximately three orders of magnitude, and also purified the functional cytokine tumor necrosis factor (TNF)-α. Additionally, utilization of the Omp38 signal peptide of A. baumannii enabled the extracellular production of variable domain of heavy chain of heavy chain (VHH) antibodies. With these advantages, mNb6-tri-20aa, a multivalent VHH that specifically binds to the spike protein of severe acute respiratory syndrome coronavirus 2, was purified from the culture supernatant, and endotoxin contamination was reduced by a factor of approximately 2 × 10 5 compared with that in conventional expression systems. A virus neutralization assay demonstrated the functionality of the purified antibody in suppressing viral infections. Moreover, we applied our system to produce ozoralizumab, a multispecific VHH that binds to human TNF-α and albumin and are marketed as a rheumatoid arthritis drug. We successfully purified a functional antibody from endotoxin contamination. This system establishes a new, completely endotoxin-free platform for the expression of recombinant proteins, which distinguishes it from other bacterial expression systems, and holds promise for future applications., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)

π-Conjugated molecules are viewed as fundamental components in forthcoming molecular nanoelectronics in which semiconducting functional units are linked to each other via metallic molecular wires. However, it is still challenging to construct such block cooligomers on the surface. Here, we present a synthesis of [18]-polyene-linked Zn-porphyrin cooligomers via a two-step reaction of the alkyl groups on Cu(111) and Cu(110). Nonyl groups (-C 9 H 19 ) substituted at the 5,15- meso positions of Zn-porphyrin were first transformed to alkenyl groups (-C 9 H 10 ) by dehydrogenation. Subsequently, homocoupling of the terminal -CH 2 groups resulted in the formation of extended [18]-polyene-linked porphyrin cooligomers. The structures of the products at each reaction step were investigated by bond-resolved scanning tunneling microscopy at low temperatures. A combination of angle-resolved photoemission spectroscopy and density functional theory calculations revealed the metallic property of the all trans [18]-polyene linker on Cu(110). This finding may provide an approach to fabricate complex nanocarbon structures on the surface.

Tracking the behavior of mechanochromic molecules provides valuable insights into force transmission and associated microstructural changes in soft materials under load. Herein, we report a dual ratiometric fluorescence (FL) analysis for monitoring both mechanical polymer chain stretching and strain-induced crystallization (SIC) of polymers. SIC has recently attracted renewed attention as an effective mechanism for improving the mechanical properties of polymers. A polyurethane (PU) film incorporating a trace of a dual-emissive flapping force probe (N-FLAP, 0.008 wt %) exhibited a blue-to-green FL spectral change in a low-stress region (<20 MPa), resulting from conformational planarization of the probe in mechanically stretched polymer chains. More importantly, at higher probe concentrations (∼0.65 wt %), the PU film showed a second spectral change from green to yellow during the SIC growth (20-65 MPa) due to self-absorption of scattered FL in a short wavelength region. The reversibility of these spectral changes was demonstrated by load-unload cycles. With these results in hand, the degrees of the polymer chain stretching and the SIC were quantitatively mapped and monitored by dual ratiometric imaging based on different FL ratios ( I 525 / I 470 and I 525 / I 600 ). Simultaneous analysis of these two mappings revealed a spatiotemporal gap in the distribution of the polymer chain stretching and the SIC. The combinational use of the dual-emissive force probe and the ratiometric FL imaging is a universal approach for the development of soft matter physics.

Overcrowded ethylenes composed of 10-methyleneanthrone and two bulky aromatic rings contain a twisted carbon-carbon double (C=C) bond as well as a folded anthrone unit. As such, they are unique frustrated aromatic enes (FAEs). Various colored crystals of these FAEs, obtained in different solvents, correspond to multiple metastable conformations of the FAEs with various twist and fold angles of the C=C bond, as well as various dihedral angles of attached aryl units with respect to the C=C bond. The relationships between color and these parameters associated with conformational features around the C=C bond were elucidated in experimental and computational studies. Owing to the fact that they are separated by small energy barriers, the variously colored conformations in the FAE crystal change in response to various external stimuli, such as mechanical grinding, hydrostatic pressure and thermal heating., (© 2022 Wiley-VCH GmbH.)

Polymer gels have recently attracted attention for their application in flexible devices, where mechanically robust gels are required. While there are many strategies to produce tough gels by suppressing nanoscale stress concentration on specific polymer chains, it is still challenging to directly verify the toughening mechanism at the molecular level. To solve this problem, the use of the flapping molecular force probe (FLAP) is promising because it can evaluate the nanoscale forces transmitted in the polymer chain network by ratiometric analysis of a stress-dependent dual fluorescence. A flexible conformational change of FLAP enables real-time and reversible responses to the nanoscale forces at the low force threshold, which is suitable for quantifying the percentage of the stressed polymer chains before structural damage. However, the previously reported FLAP only showed a negligible response in solvated environments because undesirable spontaneous planarization occurs in the excited state, even without mechanical force. Here, we have developed a new ratiometric force probe that functions in common organogels. Replacement of the anthraceneimide units in the flapping wings with pyreneimide units largely suppresses the excited-state planarization, leading to the force probe function under wet conditions. The FLAP-doped polyurethane organogel reversibly shows a dual-fluorescence response under sub-MPa compression. Moreover, the structurally modified FLAP is also advantageous in the wide dynamic range of its fluorescence response in solvent-free elastomers, enabling clearer ratiometric fluorescence imaging of the molecular-level stress concentration during crack growth in a stretched polyurethane film.

Understanding the microviscosity of soft condensed matter is important to clarify the mechanisms of chemical, physical or biological events occurring at the nanoscale. Here, we report that flapping fluorophores (FLAP) can serve as microviscosity probes capable of detecting small changes. By the ratiometric fluorescence analysis, one of the FLAP probes detects a macroscopic viscosity change of a few cP, occurring at the thermal phase transition of a nematic liquid crystal. We discuss the impact of the chemical structure on the detection capability, and the orientation of the FLAP molecules in the ground and excited states. This work contributes to experimentally providing a molecular picture of liquid crystals, which are often viewed as a continuum.

On-surface chemical reaction has become a very powerful technique to synthesize nanostructures by linking small molecules in the bottom-up approach. Given the fact that most reactants are simultaneously activated at certain temperatures, a sequential reaction in a controlled way has remained challenging. Here, we present an on-surface synthesis of multi-block co-oligomers from trifluoromethyl (CF 3 ) substituted porphyrin metal complexes. The oligomerization on Au(111) is demonstrated with a combination of bond-resolved scanning probe microscopy and density functional theory (DFT) calculations. Even after the first oligomerization of single monomer unit, the termini of the oligomer keep the CF 3 group, which can be used as a reactant for further coupling in a sequential order. Consequently, copper, cobalt, and palladium complexes of bisanthracene-fused porphyrin oligomers were linked with each other in a designed order., (© 2021 Wiley-VCH GmbH.)

Single-molecule spectroscopy (SMS) of a dual fluorescent flapping molecular probe (N-FLAP) enabled real-time nanoscale monitoring of local free volume dynamics in polystyrenes. The SMS study was realized by structural improvement of a previously reported flapping molecule by nitrogen substitution, leading to increased brightness (22 times) of the probe. In a polystyrene thin film at the temperature of 5 K above the glass transition, the spectra of a single N-FLAP molecule undergo frequent jumps between short- and long-wavelength forms, the latter one indicating planarization of the molecule in the excited state. The observed spectral jumps were statistically analyzed to reveal the dynamics of the molecular environment. The analysis together with MD and QM/MM calculations show that the excited-state planarization of the flapping probe occurs only when sufficiently large polymer free volume of more than, at least, 280 Å 3 is available close to the molecule, and that such free volume lasts for an average of 1.2 s.

Flapping fluorophores (FLAP) with a flexible 8π ring are rapidly gaining attention as a versatile photofunctional system. Here we report a highly photostable "flapping peryleneimide" with an unprecedented fluorogenic mechanism based on a bent-to-planar conformational change in the S 1 excited state. The S 1 planarization induces an electronic configurational switch, almost quenching the inherent fluorescence (FL) of the peryleneimide moieties. However, the FL quantum yield is remarkably improved with a prolonged lifetime upon a slight environmental change. This fluorogenic function is realized by sensitive π-conjugation design, as a more π-expanded analogue does not show the planarization dynamics. With strong visible-light absorption, the FL lifetime response synchronized with the flexible flapping motion is useful for the latest optical techniques such as FL lifetime imaging microscopy (FLIM)., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mechanical control of the molecular energy landscape is an important issue in modern materials science. Mechanophores play a unique role in that the mechanical responses are induced against the activation barrier for intramolecular transformation with the aid of external forces. Here we report an unprecedented activation process of a flexible flapping mechanophore. Namely, thermal void collapse in a crystalline phase triggers mechanophore compression in a definite proportion. Unfavored conformational planarization of the flapping mechanophore is compulsorily induced by packing force, leading to a total energy gain in crystal packing. Fluorescence chromism indicates extended π conjugation resulting from the mechanophore compression, giving rise to an energy transfer from the unpressed to compressed conformers.

A set of flapping acene dimers fused with an 8π cyclooctatetraene (COT) ring showed distinct excited-state dynamics in solution. While the anthracene dimer showed a fast V-shaped-to-planar conformational change within 10 ps in the lowest excited singlet state, reminding us of extended Baird aromaticity, the tetracene dimer and the pentacene dimer underwent intramolecular singlet fission (SF) in different manners: A fast and reversible SF with a characteristic delayed fluorescence (FL), and a fast and quantitative SF, respectively. Conformational flexibility of the fused COT linkage plays an important role in these ultrafast dynamics, demonstrating the utility of the flapping molecular series as a versatile platform for designing photofunctional systems., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aims: Myocardial ischaemia and angina have been demonstrated in patients with hypertrophic cardiomyopathy (HCM). We hypothesized that left ventricular (LV) systolic or diastolic dysfunction would be provocated by pacing tachycardia in patients with HCM., Methods and Results: We investigated LV global and regional systolic and diastolic function in 17 patients with HCM without LV outflow obstruction and 7 normal subjects by analysing LV angiograms and simultaneously obtained high-fidelity LV pressures before and after rapid cardiac pacing (150 b.p.m.). Biplane LV silhouettes were digitized frame by frame (50 frames/s). To quantify regional dynamics, the ventricular area of the right anterior oblique projection was divided into six sections originating from the midpoint of the long axis at end-diastole. There were no significant changes in LV function after pacing in normal subjects. In HCM, the ejection fractions remained unchanged. However, LV end-diastolic pressures rose (+12 mmHg, P < 0.01), and the time constants of isovolumic pressure decay were significantly increased (T(1/2): +5.2 ms, P < 0.01; T(1/)(e): +6.8 ms, P < 0.01). The LV global diastolic pressure-volume relationships and regional diastolic pressure-area relationships of regional myocardium shifted upward (indicating decreased diastolic distensibility) in all patients. These diastolic abnormalities were not accompanied by regional asynchrony or asynergy., Conclusion: Most patients with HCM have a reduced reactive capacity to chronotropic stress, which is haemodynamically characterized by evenly distributed diastolic dysfunction. In contrast with coronary artery disease, these diastolic abnormalities were not accompanied by systolic dysfunction, regional asynchrony, asynergy, or inhomogenous diastolic distensibility.

Background: Nicorandil in conjunction with percutaneous coronary intervention (PCI) has been reported to reduce reperfusion injury events and improve cardiac function in patients with acute myocardial infarction (AMI). This multicenter study was undertaken to determine the effectiveness and optimal administration of nicorandil in AMI patients., Methods and Results: Ninety-two patients with first AMI were randomly assigned to 1 of 3 groups: intracoronary administration of nicorandil (Group A), combined intravenous and intracoronary administration of nicorandil (Group B), and no nicorandil administration (Group C). The primary endpoint was a composite of the incidence of reperfusion-induced arrhythmia, chest pain, and no-reflow/slow-reflow. The secondary endpoint was the combined rate of improvement in the Thrombolysis in Myocardial Infarction frame count (cTFC) and ST resolution (STR). A significant difference was observed in the primary endpoint for Group B as compared with Group C (p<0.05). In the meantime, a significant improvement was shown in the secondary endpoint for Group B compared with Group C (p=0.04 and 0.006 for cTFC and STR, respectively)., Conclusions: Combined intravenous and intracoronary administration of nicorandil reduces reperfusion injury during PCI and improves the cTFC and STR in AMI, and appears to be preferable to intracoronary administration alone.

To assess diastolic function of the right ventricle (RV) in patients with hypertrophic cardiomyopathy (HCM), biplane RV angiograms and RV pressures were analyzed in 19 HCM patients and in 13 normal subjects. RV and left ventricle (LV) pressures were measured using catheter-tip manometers. RV volumes were obtained from frame-by-frame tracings of angiograms. Ventricular relaxation was assessed by the time constant of isovolumic pressure decay (T). The peak filling rate (PFR) and the time to PFR (TPFR) were used as parameters of early diastolic filling, and the right atrial contribution to RV filling (%AF) was used as a parameter of late diastolic filling. The T for the RV was significantly prolonged in HCM patients. However, there was no significant correlation between the T for the RV and LV, nor did the T for the RV correlate with the RV ejection fraction or interventricular septal wall thickness. The TPFR, but not PFR, was significantly greater in HCM patients, and the %AF tended to be increased in HCM, but not significantly. The RV diastolic pressure-volume relations in the HCM patients shifted upward. In conclusion, impaired isovolumic relaxation and delayed diastolic filling and decreased diastolic distensibility are present in the RV of HCM patients.

Purpose: To evaluate coronary blood flow per gram of myocardial mass and vasodilator flow reserve in patients with hypertrophic cardiomyopathy (HCM) and in healthy subjects by using breath-hold velocity-encoded cine (VEC) magnetic resonance (MR) imaging., Materials and Methods: Twenty-nine patients with HCM and nine healthy volunteers were examined. Fast VEC MR images were obtained in an oblique imaging plane perpendicular to the coronary sinus before and after intravenous injection of dipyridamole (0.56 mg/kg). The products of mean velocity and cross-sectional area of the vessel were integrated to measure blood flow. Breath-hold cine MR images encompassing the entire left ventricle were acquired to quantify the left ventricular mass., Results: In the basal state, the coronary blood flow per gram of myocardial mass was 0.74 mL/min/g +/- 0.23 in healthy subjects and 0.62 mL/min/g +/- 0.27 in patients with HCM. After administration of dipyridamole, coronary blood flow in patients with HCM increased to a level significantly less than that in healthy subjects (1.03 mL/min/g +/- 0.40 vs 2.14 mL/min/g +/- 0.51; P < .01), resulting in a severely depressed flow reserve ratio in patients with HCM compared with that in healthy subjects (1.72 +/- 0.49 vs 3.01 +/- 0.75; P < .01)., Conclusion: Breath-hold VEC MR imaging is a noninvasive technique for evaluating coronary flow per gram of myocardial mass and coronary flow reserve.

Objectives: We investigated the long-term prognosis of completely asymptomatic adult patients with hypertrophic cardiomyopathy (HC). Diagnosis of HC was suspected because of an abnormal electrocardiogram and/or cardiac murmur and confirmed by echocardiography and/or left ventricular angiography, and hemodynamic investigation., Background: Hypertrophic cardiomyopathy shows marked heterogeneity in clinical expression and prognosis. The prognosis of asymptomatic patients with HC has not been fully defined., Methods: Of 128 consecutive adult patients with HC, 58 asymptomatic patients (Group 1, mean age 42.8 years) and 70 symptomatic patients (Group 2, mean age 50.4 years) were studied to assess cardiac mortality. Mean follow-up periods were 11.0 years for Group 1 and 9.1 years for Group 2., Results: At presentation, Group 1 patients were younger and had smaller left atrial dimensions than did Group 2 patients. The annual cardiac mortality rate and the rate for sudden death alone in Group 1 were significantly lower than in Group 2 (0.9% vs. 1.9%, p < 0.05, 0.1% vs. 1.4%, p < 0.05, respectively). Although about one-third of the survivors in Group 1 had cardiac symptoms at their most recent evaluation, only one patient died suddenly compared with eight in Group 2. The annual mortality rate due to heart failure was similar in each group. Only a syncopal episode was associated with both cardiac death and sudden death for both groups combined., Conclusions: The cardiac mortality rate for completely asymptomatic adult patients with HC was very low, significantly lower than that of symptomatic patients, and there was a disproportionately low incidence of sudden death.

Newly developed Ca2+ sensitizers possess different mechanisms of action on contractile machinery. Increasing maximal Ca(2+)-activated force in addition to enhancing Ca2+ sensitivity (MCI-154, EMD 53998, and EMD 57033) could exert pronounced positive inotropy and may provide a mechanoenergetic advantage over the classic Ca2+ mobilization in the chronically failing heart. EMD 53998 and EMD 57033 prolong crossbridge attachment time, resulting in negative lusitropy. In contrast, pimobendan, levosimendan, and MCI-154 accelerate left ventricular relaxation in heart failure, because Ca2+ sensitizing action of these agents may be prominent during the early phases of contraction. Therefore, Ca2+ sensitizers can avoid the legacy of problems associated with conventional inotropic interventions and may break through "reservation" to "preservation" in the treatment of chronic heart failure.

Unlabelled: Scintigraphy with 123I-MIBG and 201TI was compared in patients with various diseases including diabetes mellitus, with and without sympathetic nervous dysfunction. This study was done to assess lung uptake of these tracers semiquantitatively., Methods: Thirty-eight patients with diabetes mellitus, seven patients with dilated cardiomyopathy (DCM), 12 patients with hypertrophic cardiomyopathy (HCM) and eight healthy subjects were studied. Sympathetic nervous dysfunction was observed in 13 of the 38 diabetic patients. Simultaneous imaging with 123I-MIBG and 201TI was performed. The ratio of lung to total injected dose count and washout rate in the lung were calculated from dynamic images acquired in the initial 2 min and static images acquired at 15 min and at 4 hr after injection of the tracers., Results: Lung uptake of 123I-MIBG at 4 hr was significantly increased in the diabetic group as compared with those in the other groups. In diabetic patients with sympathetic nervous dysfunction, the lung uptake ratio of 123I-MIBG at 4 hr was significantly higher than that in the diabetic patients without sympathetic nervous dysfunction, due to decreased clearance of 123I-MIBG from the lung. On the other hand, increased lung uptake of 201TI was observed in DCM patients at both 15 min and 4 hr. There was no significant difference between lung uptake of 201TI in diabetic patients and that in healthy subjects., Conclusion: Lung uptake of 123I-MIBG was increased and lung washout of 123I-MIBG was decreased in diabetic patients with sympathetic nervous dysfunction, while lung uptake of 201TI was not altered. lodine-123-MIBG scintigraphy of the lung may provide information on sympathetic nervous activity in diabetic patients. It is a promising method for studying the kinetics of norepinephrine in the lung because MIBG is taken up in the lung by the same mechanism as norepinephrine.

We compared the effects of nicorandil with nitroglycerin and nifedipine on left ventricular function. Intravenous nicorandil may be a balanced-typed vasodilator and useful in patients with left ventricular systolic and diastolic dysfunction.

To assess whether left ventricular (LV) diastolic function is a determinant of exercise capacity in patients who have suffered a previous myocardial infarction (MI), we investigated the relationship between maximum exercise duration and resting LV diastolic function in 65 MI patients. Each patient underwent both a symptom-limited exercise test and LV biplane angiography with simultaneous high-fidelity pressure measurements. LV relaxation was assessed by the time constants (T1/e and T1/2) of isovolumic pressure decay, and LV diastolic distensibility was assessed by the LV end-diastolic volume (V) index-pressure (P) ratio. The time constants of relaxation did not correlate with maximum exercise capacity (r = -0.19 for T1/e, NS; r = - 0.17 for T1/2, NS). LV diastolic distensibility also did not correlate with exercise capacity (r = - 0.08, NS). These results suggest that the resting LV diastolic dysfunction is unlikely to be the principal cause of exercise intolerance in MI patients without congestive heart failure.

Background: Some experimental studies in animals have shown that myocardial relaxation is prolonged with aging. However, it is not known whether aging alters ventricular isovolumic relaxation in human subjects., Methods and Results: We analyzed high-fidelity left ventricular pressures, measured by use of a catheter-tipped manometer, and biplane left ventriculograms in 55 normal subjects who underwent diagnostic cardiac catheterization but who were found to have normal cardiac anatomy and function. There were 38 men and 17 women, ranging in age from 20 to 77 years. Left ventricular isovolumic relaxation was assessed by the exponential time constants of isovolumic pressure decay with (Tb) and without (Tw) an asymptote pressure. Left ventricular volume, ejection fraction, and wall thickness or mass were calculated from left ventricular angiograms. Neither of the time constants of left ventricular relaxation correlated with age (Tb: r = .001 to .10, P = NS: Tw: r = .02 to .05, P = NS). Left ventricular systolic function (ie, ejection fraction and end-systolic volume index), heart rate, and left ventricular wall thickness or mass, which are major hemodynamic determinants of left ventricular relaxation, were not significantly affected by aging. The multivariate analysis of age and hemodynamic variables against the time constants of left ventricular relaxation also indicated that no significant relation was found between age and left ventricular relaxation., Conclusions: In the absence of coronary artery disease, systemic hypertension, left ventricular systolic dysfunction, or hypertrophy, left ventricular relaxation assessed by the time constant of isovolumic pressure decay remains essentially unchanged with normal adult aging, at least until the eighth decade.

Background: MCI-154 is a positive inotropic agent that increases the myofilament response to Ca2+. Whether MCI-154 has beneficial effects on left ventricular dysfunction in chronic heart failure is not known. We examined the effects of MCI-154 on left ventricular systolic and diastolic function in pacing-induced heart failure in dogs., Methods and Results: We studied eight anesthetized dogs before and 2 to 4 weeks after rapid right ventricular pacing. Left cineventriculograms with simultaneous left ventricular pressures (tip manometer) were obtained before and during intravenous administration of MCI-154 (I.O. microgram.kg-1.min-1 for 15 minutes) in the control and heart-failure states. Left ventricular volume dynamics was derived from frame-by-frame (20-ms) analyses of left ventricular angiograms. In heart failure, left ventricular contractility as assessed by shifts of the end-systolic pressure-volume ratio, evaluated by inferior vena cava occlusion, was improved by MCI-154 (+ 1.94 mm Hg/mL, P < .05) to an extent similar to that in the control state (+2.47 mm Hg/mL, P < .05). MCI-154 also accelerated left ventricular relaxation, assessed by the time constant of isovolumic pressure decay (T1/2), in both states. The absolute decrease in T1/2 with MCI-154 in heart failure was significantly greater than in the control state (-8.2 versus -3.1 ms, P < .05). In heart failure, MCI-154 shifted the left ventricular diastolic pressure-volume relation clearly downward, suggesting increased diastolic distensibility., Conclusions: MCI-154 improved not only left ventricular systolic function but also diastolic relaxation and distensibility in a chronic heart failure model.

Background: We investigated whether exercise-induced coronary spasms are influenced by the different exercise modes., Methods: We compared ischaemic ECG responses in 67 patients with vasospastic angina who underwent both treadmill and bicycle ergometer exercise and also coronary angiography., Results: ECG ST-segment elevation was provoked more frequently during treadmill exercise than it was during bicycle exercise (19 versus 9%, P < 0.05). Of 45 patients without significant coronary stenosis (coronary artery luminal diameter narrowing < 75%), 19 patients manifested ST-segment depression during treadmill exercise, whereas only seven patients did during bicycle exercise (42 versus 16%, P < 0.01). All patients with ST-segment elevation or depression during bicycle ergometer exercise also had ST-segment changes during treadmill exercise. Although higher systemic blood pressure levels and lower heart rates were found during bicycle exercise compared with during treadmill exercise the pressure-rate products at peak exercise did not differ between the two exercise tests., Conclusions: It seems that treadmill and bicycle exercise are different stressors in patients with vasospastic angina, and that coronary spasms are provoked more frequently during treadmill exercise than they are during bicycle exercise. The cause of this difference is not known, but it may be related in part to the difference in systemic haemodynamic or neurohumoral response.

Calsequestrin (CS) is a Ca(2+)-storing protein present in the sarcoplasmic reticulum (SR) of muscle cells. Calreticulin (CR) is a functional homologue of CS in the endoplasmic reticulum (ER) of non-muscle cells. During skeletal muscle differentiation, the major Ca(2+)-storing protein switches from CR to CS. To study the regulation of CS and CR expression in cardiomyocytes and the morphological maturation of Ca(2+)-storing sites in the SR, we examined rat hearts at various developmental stages and cultured adult cardiomyocytes by Western blotting and immunocytochemical analyses. CR was expressed in 14-day-old fetal rat cardiomyocytes, but disappeared gradually by 1 week after birth. CR reappeared in dedifferentiated adult cardiomyocytes in long-term culture. On Western blots, the concentration of CS in the heart did not change during development. Immunostaining for CS in fetal or neonatal rat cardiomyocytes revealed as scattered dots. CS-positive structures increased with development, and the regular striated distribution of CS at Z lines was completed around 3 weeks after birth. These results indicated that (1) CR expression is downregulated during cardiac differentiation and upregulated during dedifferentiation, and (2) maturation of SR involves the organization of CS-positive structure after birth.

We investigated the regression of left ventricular (LV) hypertrophy with long-term treatment of nifedipine in patients with systemic hypertension. Echocardiograms of the LV were obtained in nine patients before and at a mean of 50 months (13-105 months) after nifedipine monotherapy (30-60 mg/day). Nifedipine significantly reduced both systolic and diastolic blood pressures (BP) by a mean of -46 mmHg and -21 mmHg, respectively. With systemic BP reduction, LV mass was significantly reduced by a mean of -15%, associated with a decrease in LV posterior wall thickness and end-diastolic dimension. There was no significant change in LV fractional shortening. We conclude that nifedipine may cause regression of LV hypertrophy in systemic hypertension, and that reversal of the increase in LV mass could be maintained during long-term nifedipine treatment.

To investigate which time constant of isovolumic left ventricular pressure (LVP) decay is the most sensitive measure in acute myocardial ischemia, the time constant of isovolumic relaxation (IR) was calculated by two different models, the semilogarithmic model assuming a zero of LVP decline (TL) and an exponential model (Texp) with an asymptote (extrapolated baseline pressure to which LVP would fall if decay continued indefinitely), in 10 patients before and during ergonovine-induced vasospastic angina. Two time constants were derived from the exponential method as the times for LVP at peak negative dP/dt to decline by 1/e (Texp (1/e)) and by one half (Texp (1/2)). Three changes in LVP during isovolumic relaxation were analyzed and fitted to the two models described above: the LVP from the peak negative dP/dt 1) to when LVP fell to 5 mmHg above LV end-diastolic pressure (EDP), 2) until 40 msec had passed, and 3) to the LVP level 5 mmHg above LVEDP during coronary spasm. There were significant increases in TL, Texp (1/e) and Texp (1/2) in each period of the LVP during vasospastic angina. However, no significant change in Texp or asymptote was observed during angina. We concluded that TL measured by the semilogarithmic model assuming a zero of LVP decline and Texp (1/e) or Texp (1/2) derived from the exponential model are adequately sensitive for detecting acute myocardial ischemia due to coronary spasm.

We examined left ventricular (LV) diastolic pulsus alternans associated with systolic pulsus alternans in a patient with hypertrophic cardiomyopathy. Alternation in abnormal LV diastolic pressure waveforms persistently declining into mid-diastole (incomplete relaxation) and normal diastolic pressure were noted. Diastolic pulsus alternans was not corrected by isoproterenol and may possibly be independent of systolic pulsus alternans.