Assessment of human bioengineered cardiac tissue function in hypoxic and re-oxygenized environments to understand functional recovery in heart failure.

INTRODUCTION: Myocardial recovery is one of the targets for heart failure treatment. A non-negligible number of heart failure with reduced ejection fraction (EF) patients experience myocardial recovery through treatment. Although myocardial hypoxia has been reported to contribute to the progression of heart failure even in non-ischemic cardiomyopathy, the relationship between contractile recovery and re-oxygenation and its underlying mechanisms remain unclear. The present study investigated the effects of hypoxia/re-oxygenation on bioengineered cardiac cell sheets-tissue function and the underlying mechanisms. METHODS: Bioengineered cardiac cell sheets-tissue was fabricated with human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) using temperature-responsive culture dishes. Cardiac tissue functions in the following conditions were evaluated with a contractile force measurement system: continuous normoxia (20% O2) for 12 days; hypoxia (1% O2) for 4 days followed by normoxia (20% O2) for 8 days; or continuous hypoxia (1% O2) for 8 days. Cell number, sarcomere structure, ATP levels, mRNA expressions and Ca2+ transients of hiPSC-CM in those conditions were also assessed. RESULTS: Hypoxia (4 days) elicited progressive decreases in contractile force, maximum contraction velocity, maximum relaxation velocity, Ca2+ transient amplitude and ATP level, but sarcomere structure and cell number were not affected. Re-oxygenation (8 days) after hypoxia (4 days) was associated with progressive increases in contractile force, maximum contraction velocity and relaxation time to the similar extent levels of continuous normoxia group, while maximum relaxation velocity was still significantly low even after re-oxygenation. Ca2+ transient magnitude, cell number, sarcomere structure and ATP level after re-oxygenation were similar to those in the continuous normoxia group. Hypoxia/re-oxygenation up-regulated mRNA expression of PLN. CONCLUSIONS: Hypoxia and re-oxygenation condition directly affected human bioengineered cardiac tissue function. Further understanding the molecular mechanisms of functional recovery of cardiac tissue after re-oxygenation might provide us the new insight on heart failure with recovered ejection fraction and preserved ejection fraction.

Bandwidth adjustment and spectral defragmentation for optical networking unit using four wave mixing spectral compression.

Nonlinear optical signal processing is expected to be one of promising approaches in optical networking units (ONUs) and it requires mutual conversion between data signals and optical pulse signals for the bandwidth matching between them. We investigate four-wave mixing (FWM) based bandwidth management for ONUs and experimentally demonstrate variable bandwidth adjustment and defragmentation. Experimental results show variability in bandwidth adjustment and spectral defragmentation. Bit-error-rate (BER) measurements show an error-free operation (BER<10-9) with a power penalty of 3.75 dB after FWM-based bandwidth management in simulation.

Super spectral resolution beyond pixel Nyquist limits on multi-channel spectrometer.

Enhancement of the resolution of well-distributed multi-channel spectrometers beyond the pixel Nyquist limits while maintaining their inherent advantages such as high-speed measurement, compactness, and robustness will represent a critical step toward real-time monitoring of dynamic events. Here, we report the first super spectral resolution measurement beyond pixel Nyquist limits which was made possible by employing the Moiré effect in a commercially available Czerny-Turner type spectroscope of 4.63nm-spectral resolution. The experimental results show that the spectral resolution can be enhanced up to 0.31 nm by a factor of more than 10 with exceeding the 50-µm pixel Nyquist limits.

Strategy for monitoring decompensated heart failure treated by an oral vasopressin antagonist with special reference to the role of serum chloride: A case report.

Compared with conventional diuretic therapy, monitoring decompensated heart failure (HF) under treatment with a vasopressin antagonist is problematic because (1) use of this medication usually allows the patient free water intake to prevent drug-induced hypernatremia and (2) this medication often induces only minimal changes in the hemodynamics and blood concentration. In a 68-year-old female HF patient, use of tolvaptan did not induce much change in the urine output, presumably because of the low water intake due to a lack of thirst, but she did achieve a profound weight loss. Both the changes in chloride and sodium were negatively correlated with changes in the hemoglobin and serum creatinine, and positively correlated with changes in the mean red blood cell volume, but changes in the serum chloride were better correlated with each variable than were changes in the serum sodium. .

[Aortic Valve Replacement after Balloon Valvuloplasty for Aortic Valve Stenosis in a Dialysis Patient with Cardiogenic Shock;Report of a Case].

A 67-year-old man on chronic hemodialysis was admitted with worsening congestive heart failure due to critical aortic stenosis. Echocardiography showed severe aortic stenosis with a valve area of 0.67 cm2 and an ejection fraction of 0.31. Cardiac catheterization revealed severe pulmonary hypertension with pulmonary artery pressures of 62/32 mmHg. In the middle of cardiac catheterization, the systolic pressure declined to 60 mmHg due to cardiogenic shock. Dopamine hydrochloride and dobutamine hydrochloride infusions were necessary to maintain a systolic pressure greater than 80 mmHg. Balloon aortic valvuloplasty was urgently performed. The patient's symptoms rapidly resolved except for angina on exertion. One month later, elective aortic valve replacement was performed. The postoperative course was uneventful and the he was discharged on the 60th postoperative day. A follow-up echocardiogram 6 months postoperatively revealed normal prosthetic valve function and an ejection fraction of 0.6.

Impact of acute kidney injury on in-hospital outcomes in patients with DeBakey type III acute aortic dissection.

The relation between the incidence and severity of acute kidney injury (AKI) and clinical outcomes remains unclear in patients with DeBakey type III acute aortic dissection (AAD). We retrospectively assessed 56 patients admitted to our hospital for type III AAD within 48 hours of the onset of symptoms. The presence of AKI was identified, and its severity was staged on the basis of changes in serum creatinine (SCr) levels within 7 days after admission. We investigated the relations between AKI and clinical presentations, in-hospital complications, and predischarge renal function; AKI was observed in 20 patients (36%). After adjusting for age, gender, and body mass index, the incidence of AKI was associated with a history of hypertension, electrocardiographic ST-T changes, DeBakey type IIIb, and SCr level on admission. Maximum white blood cell count and serum C-reactive protein level were higher in patients with AKI than in those without AKI. AKI was associated with a greater incidence of in-hospital complications (70% vs 39%, p = 0.03) and higher SCr levels at discharge (1.1 [range 1.0 to 2.0] vs 0.9 [range 0.7 to 1.0] mg/dl, p = 0.0001). These associations were more pronounced in patients with relatively severe AKI. Multivariate analysis revealed that SCr level on admission and DeBakey type IIIb with renal artery involvement were major predictors of AKI. In conclusion, renal function on admission and renal artery involvement were significant risk factors for AKI, which was associated with poor outcomes and enhanced inflammatory response during hospitalization in patients with type III AAD.

Photodegradation of environmental mutagens by visible irradiation in the presence of xanthene dyes as photosensitizers.

The photodegradation of environmental mutagens, such as 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), and 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), was investigated by visible irradiation in the presence of xanthene dyes as photosensitizers. Although the environmental mutagens themselves were very stable during visible irradiation under the conditions in this study, they were effectively photodegraded in the presence of the xanthene dyes (erythrosine, rose bengal, and phloxine). Moreover, photodegradation of the mutagens was further enhanced for xanthene dyes loaded onto a water-soluble diethylaminoethyl (DEAE)-dextran anion-exchanger via ionic interactions (xanthene-dyeDEX). Photodegradation was inhibited by O2 removal from the reaction solution. In ESR spin-trapping experiments using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a trapping reagent, signals characteristic of DMPO-•OH (hydroxyl radical) were observed in the presence of xanthene-dyeDEX. These results suggest that reactive oxygen species derived from O2, such as singlet molecular oxygen (•1O2) and/or •OH, were active participants in photodegradation of the mutagens in the presence of xanthene dyes or xanthene-dyeDEX.