Dual-responsive near-infrared turn-on fluorescent probe for cancer stem cell-specific visualization.

Aldehyde dehydrogenase 1A1 (ALDH1A1) stands out as one of the most reliable intracellular biomarkers for stem cells because it is expressed in both cancer stem cells (CSCs) and normal somatic stem cells (NSCs). Although several turn-on fluorescent probes for ALDH1A1 have been developed to visualize CSCs in cancer cells, the discrimination of CSCs from NSCs is difficult. We here report an AND-type dual-responsive fluorescent probe, CHO_ßgal, the near-infrared fluorescence of which can be turned on after responding to both ALDH1A1 and ß-galactosidase. The AND-type dual responsiveness enables CSCs to be clearly visualized, whereas NSCs are non-emissive in microscopy. CSC-positive metastasis model lungs were successfully discriminated from normal lungs in ex vivo staining experiments using CHO_ßgal, whereas the single-input ALDH1A1-responsive probe failed to achieve this discrimination owing to pronounced false-positive fluorescence output from lung NSCs. In tissue slice staining experiments, even in the presence of adjacent normal tissues, the peripheral region-specific localization of CSCs was clear. The versatility of CHO_ßgal holds promise not only as a fundamental in vitro research tool for visualizing CSCs but also as a valuable asset in practical tissue staining diagnosis, significantly contributing to the assessment of cancer malignancy.

Steric Control in Activator-Induced Nucleophilic Quencher Detachment-Based Probes: High-Contrast Imaging of Aldehyde Dehydrogenase 1A1 in Cancer Stem Cells.

Turn-on fluorescence probes can visualize the enzyme activity with high contrast. We have established a new turn-on mechanism, activator-induced nucleophilic quencher detachment (AiQd), and developed AiQd-based turn-on fluorescence probes for the detection of enzymes. Herein, we demonstrate that the precise steric control efficiently quenches the fluorescence of AiQd-based turn-on probes before the enzymatic transformation. Theoretical calculation appropriately predicted the ratio of the fluorescence-quenched closed-ring form of probes. ßC5S-A, which has a sterically demanding methyl group at the ß-position of a fluorescence-quenching nucleophilic mercapto group, showed a low background signal. ßC5S-A responded to aldehyde dehydrogenase 1A1 (ALDH1A1) with high selectivity, thereby enabling high-contrast live imaging of cancer stem cells (signal-to-noise ratio >10). The ALDH1A1-responsiveness of ßC5S-A was not significantly affected by amino acids and biological thiols, such as cysteine and glutathione.

Identification of Breast Cancer Stem Cells Using a Newly Developed Long-acting Fluorescence Probe, C5S-A, Targeting ALDH1A1.

BACKGROUND/AIM: Aldehyde dehydrogenase (ALDH) 1A1 is a well-known marker for cancer stem cells (CSCs), characterized by self-renewal capacity and multidrug resistance in breast cancer. We developed a near-infrared turn-on fluorescence probe for ALDH1A1, C5S-A, which is suitable for observing and analyzing viable cells. Here, we demonstrated the utility of C5S-A in CSC research using breast cancer cell lines. MATERIALS AND METHODS: To evaluate concordance between C5S-A and conventional stem cell markers, breast cancer cells sorted for ALDEFLUOR-positive cells and for CD44+/CD24- cell populations were stained with C5S-A. Tumorigenicity of C5S-A-positive cells was examined by mammosphere formation assay and subcutaneous transplantation to immunodeficient mice. Additionally, to determine how long fluorescence from a single staining remained observable, we cultured breast cancer cells for 5 days after C5S-A staining. We then evaluated whether C5S-A-positive cells possessed resistance to cytotoxic drugs by chronological imaging. RESULTS: C5S-A staining showed good concordance with conventional breast CSC markers, and good utility for research into CSC characteristics in breast cancer cell lines, including tumorigenesis. Additionally, C5S-A was observable for more than 3 days with a single staining. Using this property, we then confirmed that C5S-A-positive cells possessed resistance to cytotoxic drugs, which is one of the characteristics of CSCs. CONCLUSION: We showed that C5S-A is suitable for CSC research using breast cancer cell lines, and confirmed its utility in observing cells over time.

An activator-induced quencher-detachment-based turn-on probe with a cationic substrate moiety for acetylcholinesterase.

We report a choline ester-grafted turn-on fluorescence probe to detect acetylcholinesterase (AChE) in living cells. The AChE-mediated hydrolysis of the choline ester moiety producing carboxylate initiates the activation of the Cy5 fluorophore quenched by an intramolecular nucleophilic mercapto group. The probe has the advantages of high AChE affinity and low cytotoxicity.

Deep-Red/Near-Infrared Turn-On Fluorescence Probes for Aldehyde Dehydrogenase 1A1 in Cancer Stem Cells.

Accumulating evidence supports that cancer stem cells (CSCs) are responsible for cancer proliferation, metastasis, and therapy resistance; therefore, an effective strategy to identify and isolate CSCs is required urgently. Because of their low invasiveness and high signal/noise ratio, "turn-on" fluorescence probes working in the deep-red/near-infrared (DR/NIR) region are one of the most attractive yet undeveloped tools for CSC detection. Herein, we report DR/NIR turn-on fluorescence probes, CS5-A and CS7-A, targeted to aldehyde dehydrogenase 1A1 as an intracellular CSC marker. In contrast to the conventional "always-on" green-fluorescent ALDEFLUOR, we succeeded in generating high-contrast (signal/noise ratio > 8.3) and wash-free in vitro CSC imaging with the DR probe C5S-A. This probe can facilitate CSC isolation with minimal contamination by autofluorescence from other tissues through fluorescence-activated cell sorting. Furthermore, the NIR absorbance/emission and turn-on properties of C7S-A allow simple and rapid CSC detection in vivo within 15 min.

Aluminum naphthalocyanine conjugate as an MMP-2-activatable photoacoustic probe for in vivo tumor imaging.

Matrix metalloproteinase-2 (MMP-2), which is one of MMPs family, is known as an extracellular gelatinase controlling cancer cell adhesion, growth, and metastasis. Because of the great interest in MMP-2 activity, the detailed protocols for evaluating MMP-2-responsive contrast agents, especially photoacoustic probes for in vivo use, are helpful for researchers in the field. We here describe the detailed synthetic procedure of MMP-2-activatable photoacoustic probe AlNc-pep-PEG consisting of aluminum naphthalocyanine, MMP-2-responsive peptide sequence, and poly(ethylene glycol), which has recently been developed in our research group. The detailed measurement protocol of photoacoustic signal intensity in vitro and in vivo by using in-house built photoacoustic signal measurement system and photoacoustic imaging apparatus are also summarized.

Successful perioperative management of a case of infective endocarditis secondary to a Lemierre's syndrome variant with severe neurological manifestations.

Lemierre's syndrome (LS) is characterized by septic thrombophlebitis of the internal jugular vein with septicemia and metastatic infection following an oropharyngeal infection. LS is rare but can cause infective endocarditis (IE), complicating IE management. We report a case of IE secondary to thrombophlebitis in the left vertebral vein following pharyngitis (LS variant) with distinctively severe manifestations, including metastatic infection and severe neurological impairment with multiple cerebral infarctions. A pedunculated abscess was noted on the left ventricular free wall. Despite the patient's highly impaired consciousness level (i.e., comatose state), we performed early surgery to remove the abscess after excluding LS-related brain complications. Preoperative antibiotics included clindamycin to cover LS-related anaerobic bacteria, and thrombophlebitis required postoperative anticoagulation. By managing LS as well as IE, the infection was controlled, and the neurological status normalized. This report provides insights into the perioperative management of IE secondary to LS.

MMP-2-Activatable Photoacoustic Tumor Imaging Probes Based on Al- and Si-Naphthalocyanines.

Enzyme-activatable photoacoustic probes are powerful contrast agents to visualize diseases in which a specific enzyme is overexpressed. In this study, aluminum and silicon naphthalocyanines (AlNc and SiNc, respectively) conjugated with matrix metalloprotease-2 (MMP-2)-responsive PLGLAG peptide sequence and poly(ethylene glycol) (PEG) as an axial ligand were designed and synthesized. AlNc-peptide-PEG conjugates AlNc-pep-PEG formed dimeric species interacting with each other through face-to-face H-aggregation in water, while SiNc-based conjugates SiNc-pep-PEG hardly interacted with each other because of the two bulky hydrophilic axial ligands. Both conjugates formed spherical nanometer-sized self-assemblies in water, generating photoacoustic waves under near-infrared photoirradiation. The treatment of MNc-peptide-PEG conjugates (M = Al, Si) with MMP-2 smoothly induced the cleavage of the PLGLAG sequence to release the hydrophilic PEG moiety, resulting in the aggregation of MNcs. By comparing the PA signal intensity changes at 680 and 760 nm, the photoacoustic signal intensity ratios were shown to be enhanced by 3-5 times after incubation with MMP-2. We demonstrated that MNc-peptide-PEG conjugates (M = Al, Si) could work as activatable photoacoustic probes in the in vitro experiment of MMP-2-overexpressed cell line HT-1080 as well as the in vivo photoacoustic imaging of HT-1080-bearing mice.

An enzyme-triggered turn-on fluorescent probe based on carboxylate-induced detachment of a fluorescence quencher.

We developed a new class of turn-on fluorescent probes for an esterase. After the esterase-mediated hydrolysis produced carboxylate (as a fluorescence activator), the fluorescence intensity was markedly increased through the detachment of a quencher moiety from the quenched Cy5 fluorophore. Because the probes based on this new activator-induced quencher-detachment (AiQd) adopt a non-immolative linker between the cleavable site and the fluorophore, the rate of the enzymatic reaction is greatly improved, without the generation of any by-products.

Impact of bilateral superior venae cavae on outcome of staged Fontan procedure.

BACKGROUND: The presence of bilateral superior venae cavae may add complexity to the performance of a bidirectional Glenn procedure (BDG). Stagnation of blood flow between the two cavopulmonary anastomoses may increase the risk of thrombosis and impair central pulmonary artery growth. METHODS: Forty patients underwent BDG from January 2004 to April 2011. The cohort was divided into two groups: those receiving bilateral BDG (b-BDG, n = 13) and those receiving unilateral BDG (u-BDG, n = 27). Operative, angiographic, and follow-up data were analyzed retrospectively. RESULTS: None of the patients experienced thrombosis. There was no difference in actuarial survival rate (u-BDG vs b-BDG, 100% vs 92% at 5 years, p = 0.15). On follow-up angiography, no difference in central pulmonary artery index was noted (78.4 ± 45.5 vs 60.4 ± 32.1, p = 0.24). Central pulmonary artery stenosis was detected in 6 patients (4 with u-BDG and 2 with b-BDG), 4 of whom (2 from each group) underwent balloon pulmonary artery plasty before the Fontan procedure. There was no difference in freedom from reintervention for central pulmonary artery stenosis (93% vs 85% at 1 year, p = 0.59). The rate of Fontan completion was comparable between groups, with similar operative variables and satisfactory outcomes. CONCLUSIONS: Bilateral BDG did not increase the risks of thrombosis and central pulmonary artery hypoplasia and can be performed safely without altering the outcome of the Fontan procedure.

[An adult case of tricuspid valve endocarditis with ventricular septal defect; report of a case].

A 50-year-old man was admitted to hospital because of an elevated fever. He had been diagnosed with ventricular septal defect in his childhood, but surgery had not been recommended. An echocardiogram showed vegetations on the tricuspid valve, severe tricuspid regurgitation and perimembranous ventricular septal defect. He was diagnosed with infective endocarditis( IE) and treated with antibiotics and diuretics. Five serious dental caries, which had probably caused IE, were found and extracted before surgery. After 4 weeks of medical treatment, we performed tricuspid valve repair and closed the ventricular septal defect. The postoperative course was uneventful. He has been free from any complication for over 3 years.

Obstruction of the left ventricular outflow tract due to pannus formation after the implantation of a carbomedics aortic valve.

Excessive pannus formation after implantation of a prosthetic valve is an infrequent but serious complication. A 69-year-old woman who had received a 19-mm CarboMedics aortic valve 11 years ago was readmitted to our hospital with dyspnea and chest oppression. Cineradiography did not show the restriction of valve movement. The aortic peak pressure gradient was calculated by Doppler echocardiography to be 104 mmHg. Based on the diagnosis of stenosis of the left ventricular outflow tract, the patient underwent reoperation. At reoperation, the pannus had formed circumferentially without disturbing the movement of the leaflet. A 19-mm St. Jude Medical Regent valve was implanted after enlargement of the aortic annulus. The patient's postoperative course was uneventful. We report this characteristic finding of pannus formation after the implantation of a CarboMedics valve in the aortic position.

[Cardioembolic stroke due to mitral annular calcification with a mobile component].

We report here a 50-year-old man on maintenance hemodialysis who presents right hemiparesis, aphasia. MRI diffusion weighted image showed an increased signal intensity in the area of the left middle cerebral artery. Transthoracic and transesophageal echocardiography revealed a mitral annular calcification (MAC) with a mobile component. After treated with heparin, follow-up echocardiography demonstrated a decrease in the size of the mobile component, but not disappeared. Intraoperative findings showed calcified attachment on the posterior mitral valve. This patient was diagnosed as having cardioembolic stroke due to a MAC with a mobile component.

Lipopolysaccharide triggers late preconditioning against myocardial infarction via inducible nitric oxide synthase.

OBJECTIVE: The aim of this study was to investigate the role of inducible nitric oxide synthase (iNOS) as a trigger in lipopolysaccharide (LPS)-induced late preconditioning against myocardial infarction. METHODS: Rats were pretreated intraperitoneally with two different doses of LPS (0.5 or 2.5 mg/kg) or normal saline (control) 24 h prior to lethal myocardial ischemia. Subsequently, all rats were subjected to a sustained 30-min coronary occlusion followed by 180-min reperfusion. In the second study, total RNA and protein were extracted from myocardium of the control and LPS-treated rats (after 4, 6 and 24 h of treatment) for reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: In LPS (2.5 mg/kg, but not 0.5 mg/kg)-treated rats receiving no pharmacological intervention, the percentage of myocardial infarct within the area at risk and left ventricle was significantly reduced to 42+/-4 and 24+/-2% (P<0.01) compared with the control group. The cardioprotection was abolished by injection of dexamethasone (4 mg/kg x 2, i.p.) or the selective iNOS inhibitor aminoguanidine (300 mg/kg x 2, s.c.) before LPS treatment. The expression of iNOS mRNA and the iNOS protein significantly increased 4 and 6 h after administration of LPS (2.5 mg/kg), respectively. The increases in iNOS mRNA and protein were eliminated by dexamethasone. But the iNOS mRNA and protein were not detectable 24 h after administration of LPS (2.5 mg/kg). CONCLUSIONS: These data provide molecular and pharmacological evidence that LPS-induced late preconditioning against myocardial infarction is triggered by iNOS.

Intestinal ischemia preconditions myocardium: role of protein kinase C and mitochondrial K(ATP) channel.

OBJECTIVE: The present study was designed to test the hypothesis that intestinal ischemia results in an early preconditioning against myocardial infarction and that the mechanism of the early preconditioning involves the activation of protein kinase C-mitochondrial K(ATP) channel signaling pathway in anesthetized rats. METHODS: Rats were either preconditioned with a 25-min occlusion of the superior mesenteric artery followed by 15 min of reperfusion or underwent a 40-min sham period. Subsequently, all rats were subjected to a sustained 30 min of coronary occlusion and 180 min of reperfusion. Infarct size was determined by triphenyltetrazolium chloride staining. RESULTS: In sham-operated rats receiving no pharmacological intervention, the percentage of myocardial infarct within the area at risk and left ventricle was 73+/-4% and 31+/-2%, respectively, and these were significantly reduced to 44+/-4% and 23+/-1% (P<0.01) after intestinal ischemia preconditioning. Intravenous injection of protein kinase C inhibitors chelerythrine (5 mg/kg) and staurosporine (50 microg/kg) or a specific mitochondrial K(ATP) channel inhibitor 5-hydroxydecanoate (5 mg/kg) 5 min before sustained myocardial ischemia abolished the preconditioning afforded by intestinal ischemia. However, hexamethonium, a ganglion blocker, did not attenuate the preconditioning. CONCLUSIONS: These data provide pharmacological evidence that protein kinase C and mitochondrial K(ATP) channel are involved in the mechanism of the early preconditioning induced by intestinal ischemia.

Amelioration of myocardial global ischemia/reperfusion injury with volume-regulatory chloride channel inhibitors in vivo.

BACKGROUND: Recently, the apoptotic volume decrease was suggested to be regulated by volume regulatory Cl- channels in cultured cell lines. We thus examined whether inhibition of volume-regulatory Cl- channels is cardioprotective, like caspase inhibition, by hindering the apoptosis of cardiomyocytes induced by global ischemia/reperfusion (I/R) in vivo. METHODS: We performed global ischemia for 8 min at 37 degrees C or 4 degrees C in isolated rat hearts, followed by 24-hr reperfusion via heterotopic heart transplantation. The heart tissue was examined by means of the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method, genomic DNA electrophoresis, and caspase-3 activity. Two blockers of volume-regulatory Cl- channels, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), and a broad-spectrum caspase inhibitor, benzoyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene (Z-Asp-DCB), were administered intravenously. Triphenyltetrazolium chloride (TTC) staining and ultrasound cardiography were performed to examine myocardial viability. The TTC-unstained region was assessed by means of horseradish peroxidase (HRP) infiltration and the TUNEL method. RESULTS: The transplanted hearts showed TUNEL-positivity and DNA laddering with a peak at 24 hr during reperfusion after ischemia at 37 degrees C, but not at 4 degrees C. NPPB and DIDS were as potent as Z-Asp-DCB for recovery of cardiac function and for blocking the appearance of TUNEL-positivity, DNA laddering, caspase 3 activity, and a TTC-unstained area. TTC-unstained areas were composed of either TUNEL- and slightly HRP-positive or TUNEL-negative and strongly HRP-positive cardiomyocytes. CONCLUSION: The present results demonstrated that myocardial DNA fragmentation, caspase activation, and loss of cardiac function after global I/R were blocked by NPPB and DIDS, similar to in the case of Z-Asp-DCB. These results suggest that inhibition of volume-regulatory Cl- channels is also effective for preventing cardiac I/R injury.