Postpartum spontaneous coronary artery dissection recovered by coronary artery bypass grafting supported with Impella device.

A 34-year-old female who had delivered a baby 9 days ago was transferred to our hospital due to sudden dyspnea and cardiogenic shock. Her electrocardiogram showed ST-segment elevation in precordial leads, and left ventricular ejection fraction was 20%.

Diagnostic significance of paradoxical left ventricular hypertrophy in detecting cardiac amyloidosis.

Background: Cardiac amyloidosis (CA) progresses rapidly with a poor prognosis. Therefore, methods for early diagnosis that are easily accessible in any hospital, are required. We hypothesized that based on the pathology of CA, morphological left ventricular hypertrophy (LVH) without electrical augmentation, namely paradoxical LVH, could be used to diagnose CA. This study aimed to investigate whether paradoxical LVH has diagnostic significance in identifying CA in patients with LVH. Methods: Patients who presented with left ventricular (LV) wall thickness ≥ 12 mm on cardiac magnetic resonance (CMR) were enrolled from a multicentre CMR registry. Paradoxical LVH was defined as a LV wall thickness ≥ 12 mm on CMR, SV1 + RV5 < 3.5 mV, and a lack of secondary ST-T abnormalities. The diagnostic significance of paradoxical LVH in identifying CA was assessed. Results: Of the 110 patients enrolled, 30 (27 %) were diagnosed with CA and 80 (73 %) with a non-CA aetiology. The CA group demonstrated paradoxical LVH more frequently than the non-CA group (80 % vs. 16 %, P < 0.001). It was an independent predictor for detecting CA in patients with LVH (odds ratio: 33.44, 95 % confidence interval: 8.325-134.3, P < 0.001). The sensitivity, specificity, positive predict value, negative predict value and accuracy of paradoxical LVH for CA detection were 80 %, 84 %, 65 %, 92 % and 83 %, respectively. Conclusions: Paradoxical LVH can be used for identifying CA in patients with LVH. Our findings could contribute to the early diagnosis of CA, even in non-specialized hospitals.

Cancer-related vulnerable lesions in patients with stable coronary artery disease.

BACKGROUND: Coronary artery disease (CAD) has become a major cause of morbidity and mortality in cancer survivors. It is still unclear whether cancer history influences lesion characteristics. The purpose of this study was to investigate cancer-related lesion morphology in patients with CAD. METHODS: This study enrolled 400 patients with stable CAD. The patients were classified into a cancer survivor group (n = 69) and a noncancer group (n = 331). We investigated coronary lesion morphology by optical coherence tomography, and we assessed the prognosis in terms of both all-cause mortality and major adverse cardiovascular events (MACE). RESULTS: Adenocarcinoma was the most common histopathological diagnosis. Serum C-reactive protein levels were significantly higher in the cancer survivor group than in the noncancer group (cancer survivors 0.12 [0.05-0.42] mg/dL vs. noncancer 0.08 [0.04-0.17] mg/dL, p = 0.019). The cancer survivor group was more likely than the noncancer group to have thrombi (cancer survivors 30.4% vs. noncancer 15.4%, p = 0.004), and layered fibrotic plaques (LFPs; cancer survivors 18.8% vs. noncancer 3.6%, p < 0.0001). Cancer survivors had poorer outcomes than noncancer controls in terms of both all-cause mortality (p = 0.020) and MACE (p = 0.036). CONCLUSIONS: Because of underlying inflammation, CAD patients with cancer had more high-risk lesions than those without cancer, which could result in poorer prognosis for the former. This result might inform the management of CAD in cancer patients in terms of secondary prevention.

Novel Indices of Coronary Physiology: Do We Need Alternatives to Fractional Flow Reserve?

Fractional flow reserve is the current invasive gold standard for assessing the ischemic potential of an angiographically intermediate coronary stenosis. Procedural cost and time, the need for coronary vessel instrumentation, and the need to administer adenosine to achieve maximal hyperemia remain integral components of invasive fractional flow reserve. The number of new alternatives to fractional flow reserve has proliferated over the last ten years using techniques ranging from alternative pressure wire metrics to anatomic simulation via angiography or intravascular imaging. This review article provides a critical description of the currently available or under-development alternatives to fractional flow reserve with a special focus on the available evidence, pros, and cons for each with a view towards their clinical application in the near future for the functional assessment of coronary artery disease.

Effects of Cangrelor as Adjunct Therapy to Percutaneous Coronary Intervention.

Percutaneous coronary intervention (PCI) in patients with angiographic evidence of intracoronary thrombus is associated with in-hospital and 30-day adverse clinical outcomes. Cangrelor, a direct, rapid-onset acting intravenous P2Y12 receptor inhibitor, has been proved to be effective by reducing peri-PCI ischemic complications in subjects who underwent PCI. This study aimed to assess the angiographic and in-hospital clinical outcomes in all-comer patients receiving cangrelor immediately before PCI at a tertiary care center. The study analyzed consecutive unselected subjects treated with cangrelor at the time the decision was made to proceed with PCI. At the end of the procedure, all patients were transitioned to oral antiplatelet therapy. The target lesion angiographic assessment of Thrombolysis in myocardial infarction flow grade (TIMI-Flow), TIMI-thrombus grade (TIMI-Thrombus), myocardial blush grade, and TIMI-myocardial perfusion grade (TMPG) was performed before and post-PCI. Clinical events were recorded during the procedure and at discharge. In total, 223 patients (244 lesions) were included in the analysis (106, 97, and 20 patientswith TIMI-Flow 0/1, TIMI-Flow 2/3, and cardiogenic shock, respectively). The overall mean age was 63 ± 12 years, 70% men and 38% with diabetes mellitus. Acute myocardial infarction was the main presentation (72%). The use of cangrelor improved TIMI-Flow, MGB, TMPG, and TIMI-Thrombus in patients with initial TIMI-Flow 0 to 2. Major bleeding rate was 2.0%. In conclusion, cangrelor was effective and safe in restoring TIMI-Flow 3, reducing thrombus burden and improving myocardial blush grade and TMPG when administered to unselected subjects who underwent PCI. Therefore, cangrelor should be considered in patients presenting with intracoronary thrombus before intervention.

Quantitative diagnostic imaging of cancer tissues by using phosphor-integrated dots with ultra-high brightness.

The quantitative sensitivity and dynamic range of conventional immunohistochemistry (IHC) with 3,3'-diaminobenzidine (IHC-DAB) used in pathological diagnosis in hospitals are poor, because enzyme activity can affect the IHC-DAB chromogenic reaction. Although fluorescent IHC can effectively increase the quantitative sensitivity of conventional IHC, tissue autofluorescence interferes with the sensitivity. Here, we created new fluorescent nanoparticles called phosphor-integrated dots (PIDs). PIDs have 100-fold greater brightness and a more than 300-fold greater dynamic range than those of commercially available fluorescent nanoparticles, quantum dots, whose fluorescence intensity is comparable to tissue autofluorescence. Additionally, a newly developed image-processing method enabled the calculation of the PID particle number in the obtained image. To quantify the sensitivity of IHC using PIDs (IHC-PIDs), the IHC-PIDs method was compared with fluorescence-activated cell sorting (FACS), a method well suited for evaluating total protein amount, and the two values exhibited strong correlation (R = 0.94). We next applied IHC-PIDs to categorize the response to molecular target-based drug therapy in breast cancer patients. The results suggested that the PID particle number estimated by IHC-PIDs of breast cancer tissues obtained from biopsy before chemotherapy can provide a score for predicting the therapeutic effect of the human epidermal growth factor receptor 2-targeted drug trastuzumab.

Prevalence of spontaneous coronary artery dissection in patients with acute coronary syndrome.

AIMS: Spontaneous coronary artery dissection (SCAD) found typically in young females without classical coronary risk factors is thought to be a very rare cause of acute coronary syndrome (ACS). The prevalence of SCAD in ACS subjects has been unclear, probably due to the nature of coronary angiography. The aim of this study was to use optical coherence tomography (OCT) to investigate the prevalence of SCAD in ACS. METHODS AND RESULTS: This study consisted of 326 patients with ACS (with or without ST-segment elevation) who underwent OCT to explore the entire culprit artery. According to OCT findings, patients were divided into a SCAD, a plaque rupture (PR), and a non-SCAD/non-PR group. OCT revealed 13 (4.0%) SCADs and 160 (49.1%) plaque ruptures in ACS subjects. The percentage of females versus males was greater in the SCAD group (SCAD: 53.8% vs. PR: 20.0% vs. non-SCAD/non-PR: 23.5%, p=0.02) while no difference was observed in age (SCAD: 67.3±13.3 vs. PR: 66.5±11.1 vs. non-SCAD/non-PR: 67.0±10.5, p=0.90). The prevalence of dyslipidemia (SCAD: 30.8% vs. PR: 63.8% vs. non-SCAD/non-PR: 67.5%, p=0.03) and current smoking (SCAD: 7.7% vs. PR: 57.9% vs. non-SCAD/non-PR: 59.7%, p<0.01) were significantly lower in the SCAD group. CONCLUSIONS: SCAD is not a rare cause for ACS, especially in females without classical coronary risk factors.

Long-term outcome after deferral of revascularization in patients with intermediate coronary stenosis and gray-zone fractional flow reserve.

BACKGROUND: A strategy of deferred percutaneous coronary intervention for coronary stenosis with fractional flow reserve (FFR) 0.75-0.80, termed the gray zone, remains a matter of debate. The aim of this study was to assess the safety of deferring revascularization for patients with FFR 0.75-0.80 compared with those with FFR >0.80. METHODS AND RESULTS: We assessed 3-year clinical outcome in 150 patients with angiographically intermediate stenosis who had revascularization deferred on the basis of FFR ≥ 0.75 (FFR 0.75-0.80, n=56; FFR >0.80, n=94). Target vessel failure (TVF), defined as a composite of cardiac death, target vessel-related myocardial infarction (MI), and ischemia-driven target vessel revascularization (TVR) was evaluated during follow-up. Cardiac death was observed in 1 patient with FFR 0.75-0.80. There was no target vessel-related MI in either group. The incidence of ischemia-driven TVR was higher in patients with FFR 0.75-0.80 than in those with FFR >0.80 (14% vs. 3%, P=0.020). TVF-free survival was significantly worse for the patients with FFR 0.75-0.80 than those with FFR >0.80 (hazard ratio, 5.2; 95% confidence intervals: 1.4-19.5; P=0.015). CONCLUSIONS: Patients with FFR 0.75-0.80 were at higher risk of TVF mainly due to TVR than those with FFR >0.80.

Effect of atorvastatin therapy on fibrous cap thickness in coronary atherosclerotic plaque as assessed by optical coherence tomography: the EASY-FIT study.

BACKGROUND: The detailed mechanism of plaque stabilization by statin therapy is not fully understood. OBJECTIVES: The aim of this study was to assess the effect of lipid-lowering therapy with 20 mg/day of atorvastatin versus 5 mg/day of atorvastatin on fibrous cap thickness in coronary atherosclerotic plaques by using optical coherence tomography (OCT). METHODS: Seventy patients with unstable angina pectoris and untreated dyslipidemia were randomized to either 20 mg/day or 5 mg/day of atorvastatin therapy. OCT was performed to assess intermediate nonculprit lesions at baseline and 12-month follow-up. RESULTS: Serum low-density lipoprotein cholesterol level was significantly lower during therapy with 20 mg/day compared with 5 mg/day of atorvastatin (69 mg/dl vs. 78 mg/dl; p = 0.039). The increase in fibrous cap thickness was significantly greater with 20 mg/day compared with 5 mg/day of atorvastatin (69% vs. 17%; p < 0.001). The increase in fibrous cap thickness correlated with the decrease in serum levels of low-density lipoprotein cholesterol (R = -0.450; p < 0.001), malondialdehyde-modified low-density lipoprotein (R = -0.283; p = 0.029), high-sensitivity C-reactive protein (R = -0.276; p = 0.033), and matrix metalloproteinase-9 (R = -0.502; p < 0.001), and the decrease in grade of OCT-derived macrophages (R = -0.415; p = 0.003). CONCLUSIONS: Atorvastatin therapy at 20 mg/day provided a greater increase in fibrous cap thickness in coronary plaques compared with 5 mg/day of atorvastatin. The increase of fibrous cap was associated with the decrease in serum atherogenic lipoproteins and inflammatory biomarkers during atorvastatin therapy. (Effect of Atorvastatin Therapy on Fibrous Cap Thickness in Coronary Atherosclerotic Plaque as Assessed by Optical Coherence Tomography: The EASY-FIT Study; NCT00700037).

High-density lipoprotein cholesterol level is associated with fibrous cap thickness in acute coronary syndrome.

BACKGROUND: Although low high-density lipoprotein cholesterol (HDL-C) level has been reported as an independent risk factor for coronary artery disease, few studies addressed the direct relationship between the presence of thin-cap fibroatheroma (TCFA) that is considered as vulnerable plaque in pathology and HDL-C level. The aim of this study was to investigate whether lesion vulnerability is related to HDL-C level in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: A total of 261 patients with ACS who underwent optical coherence tomography prior to percutaneous coronary intervention, were enrolled. Patients were divided into a TCFA group (n=124) and a non-TCFA group (n=137). TCFA was defined as a lipid plaque (lipid content in ≥1 quadrant) covered with <70 µm-thickness fibrous caps. There were no differences in patient characteristics and clinical results between the 2 groups except for HDL-C level, low-density lipoprotein cholesterol (LDL-C) level, and high-sensitive C-reactive protein (hs-CRP) level. On multivariate regression analysis, low HDL-C level (ß coefficient: 0.302, P<0.001), high LDL-C level (ß coefficient: -0.172, P=0.008), hs-CRP level (ß coefficient: -0.145, P=0.017), and current smoking (ß coefficient: -0.124, P=0.028) were identified as independent contributors to fibrous cap thickness. CONCLUSIONS: HDL-C is correlated with fibrous cap thickness of the culprit lesion in patients with ACS. HDL-C may be considered as a therapeutic target for plaque stabilization.

Robustness and compensation of information transmission of signaling pathways.

Robust transmission of information despite the presence of variation is a fundamental problem in cellular functions. However, the capability and characteristics of information transmission in signaling pathways remain poorly understood. We describe robustness and compensation of information transmission of signaling pathways at the cell population level. We calculated the mutual information transmitted through signaling pathways for the growth factor-mediated gene expression. Growth factors appeared to carry only information sufficient for a binary decision. Information transmission was generally more robust than average signal intensity despite pharmacological perturbations, and compensation of information transmission occurred. Information transmission to the biological output of neurite extension appeared robust. Cells may use information entropy as information so that messages can be robustly transmitted despite variation in molecular activities among individual cells.

Temporal decoding of MAP kinase and CREB phosphorylation by selective immediate early gene expression.

A wide range of growth factors encode information into specific temporal patterns of MAP kinase (MAPK) and CREB phosphorylation, which are further decoded by expression of immediate early gene products (IEGs) to exert biological functions. However, the IEG decoding system remain unknown. We built a data-driven based on time courses of MAPK and CREB phosphorylation and IEG expression in response to various growth factors to identify how signal is processed. We found that IEG expression uses common decoding systems regardless of growth factors and expression of each IEG differs in upstream dependency, switch-like response, and linear temporal filters. Pulsatile ERK phosphorylation was selectively decoded by expression of EGR1 rather than c-FOS. Conjunctive NGF and PACAP stimulation was selectively decoded by synergistic JUNB expression through switch-like response to c-FOS. Thus, specific temporal patterns and combinations of MAPKs and CREB phosphorylation can be decoded by selective IEG expression via distinct temporal filters and switch-like responses. The data-driven modeling is versatile for analysis of signal processing and does not require detailed prior knowledge of pathways.

Temporal coding of insulin action through multiplexing of the AKT pathway.

One of the unique characteristics of cellular signaling pathways is that a common signaling pathway can selectively regulate multiple cellular functions of a hormone; however, this selective downstream control through a common signaling pathway is poorly understood. Here we show that the insulin-dependent AKT pathway uses temporal patterns multiplexing for selective regulation of downstream molecules. Pulse and sustained insulin stimulations were simultaneously encoded into transient and sustained AKT phosphorylation, respectively. The downstream molecules, including ribosomal protein S6 kinase (S6K), glucose-6-phosphatase (G6Pase), and glycogen synthase kinase-3ß (GSK3ß) selectively decoded transient, sustained, and both transient and sustained AKT phosphorylation, respectively. Selective downstream decoding is mediated by the molecules' network structures and kinetics. Our results demonstrate that the AKT pathway can multiplex distinct patterns of blood insulin, such as pulse-like additional and sustained-like basal secretions, and the downstream molecules selectively decode secretion patterns of insulin.

Elucidating the in vivo phosphorylation dynamics of the ERK MAP kinase using quantitative proteomics data and Bayesian model selection.

Ever since reversible protein phosphorylation was discovered, it has been clear that it plays a key role in the regulation of cellular processes. Proteins often undergo double phosphorylation, which can occur through two possible mechanisms: distributive or processive. Which phosphorylation mechanism is chosen for a particular cellular regulation bears biological significance, and it is therefore in our interest to understand these mechanisms. In this paper we study dynamics of the MEK/ERK phosphorylation. We employ a model selection algorithm based on approximate Bayesian computation to elucidate phosphorylation dynamics from quantitative time course data obtained from PC12 cells in vivo. The algorithm infers the posterior distribution over four proposed models for phosphorylation and dephosphorylation dynamics, and this distribution indicates the amount of support given to each model. We evaluate the robustness of our inferential framework by systematically exploring different ways of parameterizing the models and for different prior specifications. The models with the highest inferred posterior probability are the two models employing distributive dephosphorylation, whereas we are unable to choose decisively between the processive and distributive phosphorylation mechanisms.

Androgen-specific regulation of FSH signalling in the previtellogenic ovary and pituitary of the New Zealand shortfinned eel, Anguilla australis.

The evidence for androgens having a pivotal role in the functioning of the female reproductive axis--such as initiating puberty or vitellogenesis--is mounting. However, the use of aromatizable androgens and the tissue-specific focus of most studies often make it unclear if androgenic effects throughout the axis proceed via androgen or estrogen signalling mechanisms. In this study, we assessed the effects of 11-ketotestosterone (11KT, a non-aromatizable androgen) on the pituitary and ovary of previtellogenic (PV) freshwater eels Anguilla australis, comparing them with eels naturally undergoing early vitellogenesis (EV). We found that 11KT treatment produces molecular and morpho-physiological phenotypes that were generally intermediate between PV and EV. Most notably, we demonstrated that 11KT induces effects on follicle-stimulating hormone (FSH) signalling in the pituitary and ovaries that are in opposition to each other. Thus, 11KT significantly reduced fshß subunit expression in the pituitary. At the same time, 11KT dramatically increased mRNA levels of ovarian FSH receptor and plasma levels of estradiol-17ß, very likely sensitizing the previtellogenic follicle to the FSH signal. Androgens therefore may be important in facilitating puberty in the eel.

Differential expression of Toll-like receptor 4 and human monocyte subsets in acute myocardial infarction.

OBJECTIVE: To investigate the involvement of Toll-like receptor 4 (TLR4) expression on two monocyte subsets in the pathologic processes related to acute coronary syndrome. How monocytes, which have recently been shown to comprise two distinct subsets, mediate the process of coronary plaque rupture remains to be fully elucidated. Recent studies have shown that TLR4 is involved in monocyte activation of patients with accelerated forms of atherosclerosis. METHODS: We enrolled 65 patients with acute myocardial infarction (AMI, n=22), unstable angina pectoris (UAP, n=16), and stable angina pectoris (SAP, n=27) who underwent coronary angiography and 15 healthy controls. The expression of TLR4 on two monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) was measured by flow cytometry. RESULTS: In patients with AMI, TLR4 was more expressed on circulating CD14(+)CD16(+) monocytes than on CD14(+)CD16(-) monocytes (p<0.001). The expression levels of TLR4 on CD14(+)CD16(+) monocytes were significantly elevated in patients with AMI compared with other 3 groups. TLR4 expression levels on CD14(+)CD16(+) monocytes were significantly elevated at the culprit site compared with the systemic level (p=0.044). The up-regulation of TLR4 on admission was remarkably decreased 12 days after AMI (p<0.001). In addition, plasma levels of tumor necrosis factor-α were positively correlated with TLR4 expression levels on monocytes in patients with AMI (r=0.47, p=0.027). CONCLUSION: TLR overexpression on CD14(+)CD16(+) monocytes in AMI, as demonstrated both in the circulation and at the coronary culprit site, might be associated with the pathogenesis of AMI.

Evaluation of Sycp3, Plzf and Cyclin B3 expression and suitability as spermatogonia and spermatocyte markers in zebrafish.

Recent studies in mammals have revealed the heterogeneity of spermatogonial populations which contain differentiated and undifferentiated cells that further divide into actual stem cells and potential stem cells. In fish however, there are no functional definitions, and very few molecular markers, for germ cells. In our present study, specific antibodies were raised against Sycp3, Plzf and Cyclin B3 in zebrafish and then used to determine the localization of these proteins in the testis. We wished to confirm whether these molecules were potential markers for spermatocytes and spermatogonia. Immunohistochemical observations revealed that Sycp3 is specifically localized in spermatocytes in typical nuclear patterns at each meiotic stage. Plzf was found to be localized in the nucleus of both type A and type B spermatogonia until the 8-cell clone, similar to the pattern in Plzf-positive A(single)-A(aligned) undifferentiated spermatogonia in rodents. In addition to Plzf, the localization of Cyclin B3 was predominantly detected in the nuclei of type A and early type B spermatogonia until the 16-cell clone. Additionally, Cyclin B3 protein signals were detected in germ cells in large cysts, possibly corresponding to spermatocytes at the preleptotene stage. Our present data thus show that these molecules have properties that will enable their use as markers of spermatocytes and early spermatogonia in zebrafish.

Association between circulating monocyte subsets and in-stent restenosis after coronary stent implantation in patients with ST-elevation myocardial infarction.

BACKGROUND: Recent studies have shown that monocytes in human peripheral blood are heterogeneous. The clinical significance of 2 distinct monocyte subsets as a marker of late in-stent restenosis (ISR) following implantation of bare-metal stents (BMSs) in patients with acute myocardial infarction (AMI) was examined. METHODS AND RESULTS: Seventy-one consecutive patients with AMI who underwent BMS implantation were enrolled in the study. Peripheral blood was collected 12 days after AMI onset. Two distinct monocyte subsets (CD14(+)CD16(-)CCR2(+) and CD14(+)CD16(+)CX3CR1(+)) were measured by flow cytometry. All patients underwent angiography at a scheduled follow up after 9 months. CD14(+)CD16(+)CX3CR1(+) monocyte subset counts were significantly higher in patients with restenosis than in patients without restenosis, whereas neither the total monocytes nor the CD14(+)CD16(-)CCR2(+) subset counts differed significantly between the 2 groups of patients. There was also a significant positive correlation between the CD14(+)CD16(+)CX3CR1(+) monocyte counts and angiographic late lumen loss. In multivariate analysis, the CD14(+)CD16(+)CX3CR1(+) monocyte count was an independent predictor for in-stent late lumen loss. CONCLUSIONS: CD14(+)CD16(+)CX3CR1(+) monocytes might have a role in ISR following coronary BMS implantation in patients with AMI.

Decoupling of receptor and downstream signals in the Akt pathway by its low-pass filter characteristics.

In cellular signal transduction, the information in an external stimulus is encoded in temporal patterns in the activities of signaling molecules; for example, pulses of a stimulus may produce an increasing response or may produce pulsatile responses in the signaling molecules. Here, we show how the Akt pathway, which is involved in cell growth, specifically transmits temporal information contained in upstream signals to downstream effectors. We modeled the epidermal growth factor (EGF)-dependent Akt pathway in PC12 cells on the basis of experimental results. We obtained counterintuitive results indicating that the sizes of the peak amplitudes of receptor and downstream effector phosphorylation were decoupled; weak, sustained EGF receptor (EGFR) phosphorylation, rather than strong, transient phosphorylation, strongly induced phosphorylation of the ribosomal protein S6, a molecule downstream of Akt. Using frequency response analysis, we found that a three-component Akt pathway exhibited the property of a low-pass filter and that this property could explain decoupling of the peak amplitudes of receptor phosphorylation and that of downstream effectors. Furthermore, we found that lapatinib, an EGFR inhibitor used as an anticancer drug, converted strong, transient Akt phosphorylation into weak, sustained Akt phosphorylation, and, because of the low-pass filter characteristics of the Akt pathway, this led to stronger S6 phosphorylation than occurred in the absence of the inhibitor. Thus, an EGFR inhibitor can potentially act as a downstream activator of some effectors.

A quantitative image cytometry technique for time series or population analyses of signaling networks.

BACKGROUND: Modeling of cellular functions on the basis of experimental observation is increasingly common in the field of cellular signaling. However, such modeling requires a large amount of quantitative data of signaling events with high spatio-temporal resolution. A novel technique which allows us to obtain such data is needed for systems biology of cellular signaling. METHODOLOGY/PRINCIPAL FINDINGS: We developed a fully automatable assay technique, termed quantitative image cytometry (QIC), which integrates a quantitative immunostaining technique and a high precision image-processing algorithm for cell identification. With the aid of an automated sample preparation system, this device can quantify protein expression, phosphorylation and localization with subcellular resolution at one-minute intervals. The signaling activities quantified by the assay system showed good correlation with, as well as comparable reproducibility to, western blot analysis. Taking advantage of the high spatio-temporal resolution, we investigated the signaling dynamics of the ERK pathway in PC12 cells. CONCLUSIONS/SIGNIFICANCE: The QIC technique appears as a highly quantitative and versatile technique, which can be a convenient replacement for the most conventional techniques including western blot, flow cytometry and live cell imaging. Thus, the QIC technique can be a powerful tool for investigating the systems biology of cellular signaling.