Dual phase-detected infrared photothermal microscopy.

Infrared photothermal microscopy (IPM) has recently gained considerable attention as a versatile analytical platform capable of providing spatially resolved molecular insights across diverse research fields. This technique has led to numerous breakthroughs in the study of compositional variations in functional materials and cellular dynamics in living cells. However, its application to investigate multiple components of temporally dynamic systems, such as living cells and operational devices, has been hampered by the limited information content of the IP signal, which only covers a narrow spectral window (< 1 cm-1). Here, we present a straightforward approach for measuring two distinct IPM images utilizing the orthogonality between the in-phase and quadrature outputs of a lock-in amplifier, called dual-phase IR photothermal (DP-IP) detection. We demonstrate the feasibility of DP-IP detection for IPM in distinguishing two different micro-sized polymer beads.

Monitoring the synthesis of neutral lipids in lipid droplets of living human cancer cells using two-color infrared photothermal microscopy.

There has been growing interest in the functions of lipid droplets (LDs) due to recent discoveries regarding their diverse roles. These functions encompass lipid metabolism, regulation of lipotoxicity, and signaling pathways that extend beyond their traditional role in energy storage. Consequently, there is a need to examine the molecular dynamics of LDs at the subcellular level. Two-color infrared photothermal microscopy (2C-IPM) has proven to be a valuable tool for elucidating the molecular dynamics occurring in LDs with sub-micrometer spatial resolution and molecular specificity. In this study, we employed the 2C-IPM to investigate the molecular dynamics of LDs in both fixed and living human cancer cells (U2OS cells) using the isotope labeling method. We investigated the synthesis of neutral lipids occurring in individual LDs over time after exposing the cells to excess saturated fatty acids while simultaneously comparing inherent lipid contents in LDs. We anticipate that these research findings will reveal new opportunities for studying lesser-known biological processes within LDs and other subcellular organelles.

Two-color infrared photothermal microscopy.

Infrared photothermal microscopy is an infrared (IR) imaging technique that enables non-invasive, non-destructive, and label-free investigations at the sub-micrometer scale. It has been applied in various research areas targeting pharmaceutical and photovoltaic materials as well as biomolecules in living systems. Despite its potency in observing biomolecules in living organisms, its practical application for cytological research has been restricted by the deficiency of molecular information from the IR photothermal signal, due to the narrow spectral width of a quantum cascade laser that is one of the most preferred IR excitation light sources for current IR photothermal imaging (IPI) techniques. Here, we address this issue by bringing modulation-frequency multiplexing into IR photothermal microscopy for developing a two-color IR photothermal microscopy technique. We demonstrate that the two-color IPI technique can be used to obtain the IR microscopic images of two discrete IR absorption bands and to distinguish two different chemical species in live cells with a sub-micrometer spatial resolution. We anticipate that the more general multi-color IPI technique and its use for metabolic studies of live cells could be realized by extending the present modulation-frequency multiplexing method.

Cytoplasmic Protein Imaging with Mid-Infrared Photothermal Microscopy: Cellular Dynamics of Live Neurons and Oligodendrocytes.

Mid-infrared photothermal microscopy has been suggested as an alternative to conventional infrared microscopy because in addition to the inherent chemical contrast available upon vibrational excitation, it can feasibly achieve spatial resolution at the submicrometer level. Furthermore, it has substantial potential for real-time bioimaging for the observation of cellular dynamics without photodamage or photobleaching of fluorescent labels. We performed real-time imaging of oligodendrocytes to investigate cellular dynamics throughout the life cycle of a cell, revealing details of cell division and apoptosis, as well as cellular migration. In the case of live neurons, we observed a photothermal contrast associated with traveling protein complexes on an axon, which correspond to the transport of vesicles from the cell body to the dendritic branches of the neuron through the cytoskeleton. We anticipate that mid-infrared photothermal imaging will be of great use for gaining insights into the field of biophysical science, especially with regard to cellular dynamics and functions.

Effect of multifaceted interventions on reducing return visits within 72 h after non-traumatic emergency department visits.

OBJECTIVE: The objective of the present study is to develop new multifaceted interventions to reduce return visits (RVs) based on identified risk factors related to RVs in the ED and to compare the RV rate before and after the implementation of the intervention. METHODS: The present study was a controlled before and after study that was conducted in the ED of a 900-bed tertiary hospital in an urban area. The primary outcome was the rate of unplanned RVs to the ED and hospital admission after RV. The risk and predictive factors of RVs were identified by a retrospective study of all unscheduled RVs to the ED within 72 h in 2011. We developed five new multifaceted interventions based on the results: (i) daily RV feedback; (ii) prescription set of drugs; (iii) creation of a discharge instruction sheet; (iv) early follow-up appointments of outpatient department (OPD); and (v) enhancement of referral system. A prospective interventional study in which the interventions were implemented was then conducted over 10 months, from 1 June 2012 to 31 March 2013. RESULTS: The five new multifaceted interventions significantly reduced the mean early RV rate and RV admission rate after ED discharge by an average of approximately 25%, with a maximum of approximately 55% and 47%, respectively, compared with the pre-intervention period (RV rate: P < 0.001, RV admission rate: P < 0.001). CONCLUSIONS: Multifaceted interventions based on identified risk factors for early RV after ED discharge had a positive effect on reducing RVs and the admission rate after RVs for adult patients within 72 h of non-traumatic ED visits.

Perception of radiation dose and potential risks of computed tomography in emergency department medical personnel.

OBJECTIVE: Use of computed tomography (CT) continues to increase, but the relatively high radiation doses associated with CT have raised health concerns such as future risk of cancer. We investigated the level of awareness regarding radiation doses and possible risks associated with CT in medical personnel (MP). METHODS: This study was conducted from April to May 2012 and included physicians and nurses who worked in the emergency department of 17 training hospitals. The questionnaire included measurement of the effect of CT or radiography on health using a 10-point numerical rating scale, estimation of the radiation dose of one abdominal CT scan compared with one chest radiograph, and perception of the increased lifetime risk of cancer associated with CT. RESULTS: A total of 354 MP participated in this study: 142 nurses, 87 interns, 86 residents, and 39 specialists. Interns were less aware of the effects of CT or radiography on health than other physicians or nurses (mean±SD of 4.8±2.7, 5.9±2.7, 6.1±2.7, and 6.0±2.2 for interns, residents, specialists, and nurses, respectively; P<0.05). There was a significant difference in knowledge about the relative radiation dose of one abdominal CT scan compared with one chest radiograph between physicians and nurses (48.6% vs. 28.9% for physicians vs. nurses, P<0.05). MP perceived an increased risk of cancer from radiation associated with CT. CONCLUSION: MP perceive the risk of radiation associated with CT, but their level of knowledge seems to be insufficient.

Awareness and knowledge of sepsis in the general Korean population: comparison with the awareness and knowledge of acute myocardial infarction and stroke.

OBJECTIVE: Patients with severe sepsis or septic shock require timely, aggressive management to improve their outcomes, and early presentation of patients to the hospital may also be important. Thus, public awareness about sepsis may be important for improved outcomes. However, there are no studies regarding the public awareness of sepsis in the general Korean population. Therefore, the objective of this survey was to gain insight into the public awareness of sepsis. METHODS: Prospective paper-based and web-based surveys were issued between May and June 2013 to adults aged ≥18 years. RESULTS: A total of 1,081 participants responded to the survey (394 paper-based and 687 web-based). Mean age was 38.7±11.4 years, and 541 participants (50%) were men. Of the 1,081 participants, 831 (76.9%) had heard of the term "sepsis." Of these participants, only 295 (35%) responded correctly regarding the definition of sepsis. However, 1,019 participants (94.3%) had heard of acute myocardial infarction, and 817 of these (80%) correctly defined acute myocardial infarction. Regarding stroke, 1,047 (96.9%) had heard of stroke, and 975 of these responded (93.1%) correctly to the definition of stroke. CONCLUSION: There is poor public awareness about sepsis compared with that of acute myocardial infarction and stroke. This may limit the timely management of severe sepsis and septic shock.

Bacteremia prediction model using a common clinical test in patients with community-acquired pneumonia.

PURPOSE: The aim of this study was to construct a bacteremia prediction model using commonly available clinical variables in hospitalized patients with community-acquired pneumonia (CAP). BASIC PROCEDURES: A prospective database including patients who were diagnosed with CAP in the emergency department was analyzed. Independent risk factors were investigated by using multivariable analysis in 60% of the cohort. We assigned a weighted value to predictive factor and made a prediction rule. This model was validated both internally and externally with the remaining 40% of the cohort and a cohort from an independent hospital. The low-risk group for bacteremia was defined as patients who have a risk of bacteremia less than 3%. MAIN FINDINGS: A total of 2422 patients were included in this study. The overall rate of bacteremia was 5.7% in the cohort. The significant factors for predicting bacteremia were the following 7 variables: systolic blood pressure less than 90 mm Hg, heart rate greater than 125 beats per minute, body temperature less than 35 °C or greater than 40 °C, white blood cell less than 4000 or 12,000 cells per microliter, platelets less than 130,000 cells per microliter, albumin less than 3.3 g/dL, and C-reactive protein greater than 17 mg/dL. After using our prediction rule for the validation cohorts, 78.7% and 74.8% of the internal and external validation cohorts were classified as low-risk bacteremia groups. The areas under the receiver operating characteristic curves were 0.75 and 0.79 for the internal and external validation cohorts. PRINCIPAL CONCLUSIONS: This model could provide guidelines for whether to perform blood cultures for hospitalized CAP patients with the goal of reducing the number of blood cultures.

Does the quality of chest compressions deteriorate when the chest compression rate is above 120/min?

OBJECTIVES: The quality of chest compressions along with defibrillation is the cornerstone of cardiopulmonary resuscitation (CPR), which is known to improve the outcome of cardiac arrest. We aimed to investigate the relationship between the compression rate and other CPR quality parameters including compression depth and recoil. METHODS: A conventional CPR training for lay rescuers was performed 2 weeks before the 'CPR contest'. CPR anytime training kits were distributed to respective participants for self-training on their own in their own time. The participants were tested for two-person CPR in pairs. The quantitative and qualitative data regarding the quality of CPR were collected from a standardised check list and SkillReporter, and compared by the compression rate. RESULTS: A total of 161 teams consisting of 322 students, which includes 116 men and 206 women, participated in the CPR contest. The mean depth and rate for chest compression were 49.0±8.2 mm and 110.2±10.2/min. Significantly deeper chest compression depths were noted at rates over 120/min than those at any other rates (47.0±7.4, 48.8±8.4, 52.3±6.7, p=0.008). Chest compression depth was proportional to chest compression rate (r=0.206, p<0.001), but there were significantly more incomplete chest recoils at the rate of over 120/min than at any other rates (9.8%, 6.3%, 25.6%, p=0.011). CONCLUSIONS: The study showed conflicting results in the quality of chest compression including chest compression depth and chest recoil by chest compression rate. Further evaluation regarding the upper limit of the chest compression rate is needed to ensure complete full chest wall recoil while maintaining an adequate chest compression depth.

A risk stratification model of acute pyelonephritis to indicate hospital admission from the ED.

OBJECTIVES: There are no guidelines regarding the hospitalization of female patients with acute pyelonephritis (APN); therefore, we performed a retrospective analysis to construct a clinical prediction model for hospital admission. METHODS: We conducted a retrospective analysis of a prospective database of women diagnosed as having APN in the emergency department between January 2006 and June 2012. Independent risk factors for admission were determined by multivariable logistic regression analysis in half of the patients in this database. The risk of admission was categorized into 5 groups. The internal and external validations were conducted using the remaining half of the patients and 192 independent patients, respectively. RESULTS: Independent risk factors for admission were age of 65 years or greater (odds ratio [OR], 2.62; 1 point), chill (OR, 2.40; 1 point), and the levels of segmented neutrophils greater than 90% (OR, 2.00; 1 point), serum creatinine greater than 1.5 mg/dL (OR, 2.41; 1 point), C-reactive protein greater than 10 mg/dL (OR, 2.37; 1 point), and serum albumin less than 3.3 g/dL (OR, 7.36; 2 points). The admission risk scores consisted of 5 categories, which were very low (0 points; 5.9%), low (1 point; 10.7%), intermediate (2 points; 20.7%), high (3-4 points; 51.9%), and very high (5-7 points; 82.8%) risk, showing an area under the curve of 0.770. The areas under the curve of the internal and external validation cohorts were 0.743 and 0.725, respectively. CONCLUSION: This model can provide a guideline to determine the admission of women with APN in the emergency department.