Fluorescence spectroscopy and imaging of myocardial apoptosis

Fluorometry is used to detect intrinsic flavoprotein (FP) and nicotinamide adenine dinucleotide NADH signals in an open-chest rabbit model of myocardial ischemia-reperfusion injury. Myocyte apoptosis has been shown clinically to contribute to infarct size following reperfusion of ischemic myocardium. A noninvasive means of assessing apoptosis in this setting would aid in the treatment of subsequent ventricular remodeling. We show that in vivo fluorometry can be useful in apoptosis detection in open-chest surgeries. Specific changes in myocardial redox states have been shown to indicate the presence of apoptosis. Two main mitochondrial intrinsic fluorophores, NADH and FP signals, were measured during normoxia, ischemia, and reperfusion experimental protocol. Ischemia was induced by occlusion of the largest branch of the circumflex coronary artery and fluorescence signals are collected by applying two different fluorescence techniques: in vivo fluorometry and postmortem cryoimaging. The first technique was employed to detect FP and NADH signals in vivo and the latter technique uses freeze trapping and lowtemperature fluorescence imaging. The heart is snap frozen while still in the chest cavity to make a snapshot of the metabolic state of the tissue. After freezing, the ischemic area and its surrounding border zone were excised and the sample was embedded in a frozen buffer for cryoscanning. These two data sets, in vivo fluorometry and low temperature redox scanning, show consistent extreme oxidation of the mitochondrial redox states (higher redox ratio) suggesting the initiation of apoptosis following reperfusion. This represents the first attempt to assess myocyte apoptosis in the beating heart

Simultaneous Monitoring of Photoinduced Absorption Signals and Short-Circuit Photocurrent during Photoexcitation in Dye-Sensitized Solar Cells

Continuous-wave photoinduced absorption (PIA) measurements were performed simultaneously with photovoltage or photocurrent (PC) measurements to monitor slow transfer processes of electron carriers in operating dye-sensitized solar cells (DSCs). Time-resolved simultaneous experiments demonstrate that the rise curve of PC during photoexcitation is delayed against that of PIA signals. The delay is analyzed by a model that considers effects of electron transfer on PIA signals and shown to be determined by transfer time of electrons over the TiO₂ film. On the contrary, no delay is found between the decay curves at excitation–off of PIA signals and PC, suggesting that the transfer kinetics of TiO₂ electron varies after the electrons reach the transparent electrode. These spectral features indicate that the time-resolved PIA signals of TiO₂ electron under short-circuit conditions are primarily determined by its slow transfer process and that the simultaneous PIA experiments are effective to study the slow electron-transfer processes of DSCs

Comparison of Diagnostic Yield and Safety of Serial Pancreatic Juice Aspiration Cytologic Examination (SPACE) with Different Indications

We assessed whether there are differences in the diagnostic yield and safety of serial pancreatic juice aspiration cytologic examination (SPACE) among different indications. We retrospectively analyzed 226 patients who underwent SPACE. They were classified into group A (patients with pancreatic masses, including advanced adenocarcinoma, sclerosing pancreatitis, or autoimmune pancreatitis), group B (suspicious pancreatic carcinoma patients without obvious pancreatic masses, including small pancreatic carcinoma, carcinoma in situ, or benign pancreatic duct stenosis), and group C (intraductal papillary mucinous neoplasm, IPMN). There were 41, 66, and 119 patients, with malignancy diagnosed in 29, 14, and 22 patients, in groups A, B, and C, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 69%, 100%, 100%, 57%, and 78% in group A; 79%, 98%, 92%, 94%, and 94% in group B; and 27%, 87%, 32%, 84%, and 76% in group C, respectively. PEP was observed in three (7.3%), three (4.5%), and fifteen (13%) patients in group A, B, and C, respectively (p = 0.20). SPACE is useful and safe in patients with suspicious small pancreatic carcinoma. However, it has limited efficacy and might not be recommended in patients with IPMN because of the high frequency of PEP

Sex-related resistance to myocardial ischemia-reperfusion injury is associated with high constitutive ARC expression

The female sex has been associated with improved myocardial salvage after ischemia and reperfusion (I/R). Estrogen, specifically 17β-estradiol, has been demonstrated to mediate this phenomenon by limiting cardiomyocyte apoptosis. We sought to quantitatively assess the effect of sex, ovarian hormone loss, and I/R on myocardial Bax, Bcl-2, and apoptosis repressor with caspase recruitment domain (ARC) expression. Male (n = 48), female (n = 26), and oophorectomized female (n = 20) rabbits underwent 30 min of regional ischemia and 3 h of reperfusion. The myocardial area at risk and infarct size were determined using a double-staining technique and planimetry. In situ oligo ligation was used to assess apoptotic cell death. Western blot analysis was used to determine proapoptotic (Bax) and antiapoptotic (Bcl-2 and ARC) protein levels in all three ischemic groups and, additionally, in three nonischemic groups. Infarct size (43.7 ± 3.2%) and apoptotic cell death (0.51 ± 0.10%) were significantly attenuated in females compared with males (56.4 ± 1.6%, P < 0.01, and 4.29 ± 0.95%, P < 0.01) and oophorectomized females (55.7 ± 3.4%, P < 0.05, and 4.36 ± 0.51%, P < 0.01). Females expressed significantly higher baseline ARC levels (3.62 ± 0.29) compared with males (1.78 ± 0.18, P < 0.01) and oophorectomized females (1.08 ± 0.26, P < 0.01). Males expressed a significantly higher baseline Bax-to-Bcl-2 ratio (4.32 ± 0.99) compared with females (0.65 ± 0.13, P < 0.01) and oophorectomized females (0.42 ± 0.10, P < 0.01). I/R significantly reduced Bax-to-Bcl-2 ratios in males. In all other groups, ARC levels and Bax-to-Bcl-2 ratios did not significantly change. These results support the conclusion that in females, endogenous estrogen limits I/R-induced cardiomyocyte apoptosis by producing a baseline antiapoptotic profile, which is associated with estrogen-dependent high constitutive myocardial ARC expression