Aplastic Anemia With Thrombosis Following the Administration of Immunosuppressant and Thrombopoietin Receptor Agonist (TPO-RA).

Thrombopoietin receptor agonist (TPO-RA) is effective for aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP). However, the risk of thrombosis during ITP treatment with TPO-RA is higher than without TPO-RA. It is unclear whether TPO-RA increases the risk of thrombosis in patients with AA. We report a case of a 66-year-old female with severe AA having paroxysmal nocturnal hemoglobinuria (PNH) clones in the peripheral blood who developed ischemic colitis after three days of starting eltrombopag. Contrast-enhanced computed tomography showed ischemic colitis and contrast enhancement defect in the left atrial appendage, which indicated a thrombus in the heart. Stopping eltrombopag and providing supportive care improved her symptoms, and her blood cell counts gradually increased. Thrombosis should be considered when TPO-RA is administered during the immunosuppressive treatment of AA.

Association of the quantitative oral health status of patients with COVID-19 with their organ status and immunity: A single-centre observational study.

OBJECTIVES: To evaluate the prevalence of oral complications in patients with severe COVID-19; investigate the association between their oral health, organ status, and immunity; and determine whether the resazurin disc test is an effective substitute for the Oral Assessment Guide. RESEARCH METHODOLOGY/DESIGN: A single-centre observational study. SETTING: Intensive care unit with restricted access specialising in extracorporeal membrane oxygenation for COVID-19 treatment. MAIN OUTCOME MEASURES: We investigated the oral health of 13 patients with COVID-19 receiving extracorporeal membrane oxygenation therapy between April and December 2021 using the Oral Assessment Guide and colour reactive resazurin disc test. The Sequential Organ Failure Assessment and Prognostic Nutritional Index were used to assess organ status and immunity, respectively. The correlation of oral health status with organ status and immunity was investigated. RESULTS: High bacterial levels, revealed by the resazurin disc test, were associated with elevated Oral Assessment Guide scores, indicating oral health deterioration, particularly in terms of teeth and dentures. Increased Sequential Organ Failure Assessment scores and decreased Prognostic Nutritional Index were correlated with poor oral health, revealed by the Oral Assessment Guide and resazurin disc test. CONCLUSION: Poor oral health is an important risk factor for severe COVID-19 complications in patients admitted to an intensive care unit. The Oral Assessment Guide and resazurin disc test can evaluate oral conditions; however, the resazurin disc test is quantitative and does not require salivary specimens to be transferred outside the patient ward for evaluation. The resazurin disc test can be a useful substitute for the Oral Assessment Guide in intensive care units with restricted access. IMPLICATIONS FOR CLINICAL PRACTICE: The resazurin disc test can be used for quantitative assessment of patients' oral condition in isolation wards. Multidisciplinary management of patients with COVID-19 should be promoted and involve oral healthcare providers such as dentists and dental hygienists.

Serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study.

The aim of this study was to clarify the relationship between fasting and nonfasting serum triglyceride (TG) levels and the incidence of hypertension in a general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 3202 participants without hypertension at baseline were included in the present analysis. TG levels were classified as quartile 1 (<0.82 mmol/L), quartile 2 (0.83-1.13 mmol/L), quartile 3 (1.14-1.70 mmol/L) and quartile 4 (≥1.71 mmol/L) for men, and as quartile 1 (<0.70 mmol/L), quartile 2 (0.71-0.96 mmol/L), quartile 3 (0.97-1.34 mmol/L) and quartile 4 (≥1.35 mmol/L) for women. The outcome was incident hypertension. During an average follow-up of 4.4 years, 983 participants developed hypertension, according to the Cox proportional hazards model. The annual incidence of hypertension increased with an elevation in TG levels for men (5.88% in quartile 1, 8.30% in quartile 2, 7.62% in quartile 3, and 9.82% in quartile 4). This association was significant, even after adjustment for other risk factors: hazard ratio 1.41 [95% CI 1.07-1.85] for quartile 2, 1.30 [0.99-1.71] for quartile 3, and 1.59 [1.22-2.08] for quartile 4 compared with quartile 1 (p = 0.041 for trend). In contrast, there was no clear association between serum TG levels and the incidence of hypertension after adjustment for confounding factors among women (p = 0.240 for trend). High levels of serum TG were associated with the future incidence of hypertension in a general population of Japanese men but were not associated with that in women. Casual serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study.

Analyses of the Posttranscriptional Regulation of CCN Genes: Approach to Multiple Steps of CCN2 Gene Expression.

Cells generally control the concentration of mRNA via transcriptional and posttranscriptional regulation, so the separate contributions of synthesis and degradation (decay) cannot be discriminated by the quantification of mRNA. To elucidate the contribution of posttranscriptional regulation, all experimental procedures for the analysis of the total transcript level, transcriptional induction, degradation of the target mRNA, and inhibition of mRNA translation are performed either individually or in combination. From our experience, measurement of the steady-state levels of mRNA using quantitative real-time polymerase chain reaction is an essential first step in quantifying the ccn2 gene expression. Subsequently, the effect of transcription rates should be assessed by reporter assays of the ccn2 promoter and nuclear run-on assays. The stability of ccn2 mRNAs is then evaluated in the presence of a metabolic inhibitor actinomycin D, followed by mRNA degradation assays in vitro. Finally, repression of ccn2 mRNA translation can be estimated by comparing the expression of mRNA and protein changes. We herein report the strategic methods used in a series of analyses to elucidate the possible involvement of the posttranscriptional regulatory mechanism of the ccn2 gene and show how this approach can, in theory, be used to elucidate the posttranscriptional regulation of other genes belonging to the CCN family.

Prevalence of and risk factors for postoperative complications after lower third molar extraction: A multicenter prospective observational study in Japan.

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient's background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040-1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333-3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050-2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079-6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574-4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction.

Induction of potassium channel regulator KCNE4 in a submandibular lymph node metastasis model.

Cancer cells often metastasize to the lymph nodes (LNs) before disseminating throughout the body. Clinically, LN metastasis correlates with poor prognosis and influences treatment options. Many studies have shown that cancer cells communicate with immune and stromal cells to prepare a suitable niche for metastasis. In this study, mice were injected with B16-F10 murine melanoma cells to generate a tongue submandibular lymph node (SLN) metastasis model in which genes of interest could be investigated. Microarray analyses were performed on SLNs, identifying 162 upregulated genes, some of which are known metastasis genes. Among these upregulated genes, Kcne4, Slc7a11, Fscn1, and Gadd45b were not associated with metastasis, and increased expression of Kcne4 and Slc7a11 was confirmed by real-time PCR and immunohistochemistry. The roles of KCNE4 in chemokine production and cell adhesion were examined using primary lymphatic endothelial cells, and demonstrated that Ccl17 and Ccl19, which are involved in melanoma metastasis, were upregulated by KCNE4, as well as Mmp3 matrix metalloproteinase. Expression of KCNE4 was detected in human LNs with metastatic melanoma. In conclusion, we found that LN metastatic melanoma induces KCNE4 expression in the endothelium of LNs.

Effectiveness of change from suvorexant to lemborexant drug in the treatment of sleep disorders.

BACKGROUND: This study aimed to examine the effects of a change in medication from suvorexant to lemborexant among patients with insomnia. METHODS: Patients with chronic insomnia who had persistent insomnia for 3 months or longer and who had been taking suvorexant for 3 months or longer were selected. The participants were divided into two groups: the 'modified' group and the 'non-modified' group. Four sub-types of insomnia (i.e., difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, and non-restorative sleep) were investigated. Logistic regression was used to investigate improvements in both the groups after 12 weeks. RESULTS: Among the 77 participants, 43 and 34 patients were in the modified drug group and the non-modified drug group, respectively. Comparing sleep disorders between the two groups, we found significant improvement after 12 weeks in the modified drug group in terms of difficulty initiating sleep, compared with the non-modified drug group (odds ratio = 0.036, P = 0.008, 95% CI = 0.003-0.415). However, no significant differences were found between the two groups in terms of difficulty maintaining sleep, early-morning awakening, and non-restorative sleep. CONCLUSIONS: Sleep disorders can be treated by alleviating difficulties in initiating sleep by changing from suvorexant to lemborexant. In addition, it was confirmed that the drug change caused no serious side effects and that it was highly safe and tolerated.

The Association between the Oral-Gut Axis and the Outcomes of Severe COVID-19 Patients Receiving Extracorporeal Membrane Oxygenation: A Case-Control Study.

The novel conceptual disease model, the oral-gut axis, which represents the immunomodulatory mutual relationship between oral and gut microbial compartments, has been attracting attention in relation to systemic health issues. We investigated whether this unique crosstalk influences the systemic condition of patients with COVID-19 infections who received extracorporeal membrane oxygenation (ECMO) in the intensive care unit (ICU) during April and December 2020. In this case-control study, patients were divided into two groups according to their survival (total entry size, n = 21; survivors, n = 13; non-survivors, n = 8). Patients were evaluated using the oral assessment guide from Fukuoka University (OAG-F) and the Bristol Stool Form Scale (BSFS) to examine the oral and fecal conditions. A blood-based inflammatory factor, the neutrophil-to-lymphocyte ratio (NLR), was used as an indicator of systemic immunity. The high total OAG-F scores were associated with both elevated BSFS and NLR values, and a mutually positive correlation between BSFS and NLR was observed. This indicated an interplay between oral deterioration, gut dysbiosis, and the impairment of immunity. Furthermore, oral deterioration was more frequently observed in non-survivors on day 14 of ICU admission. In addition, on days 7 and 21 of ICU admission, impaired immunity, reflected by an elevated NLR, was observed in non-survivors. However, the distribution of the gut microbiome-reflected by increased BSFS values-with the time it was examined was not directly observed in non-survivors. Taken together, these findings suggested that oral-gut health may be specifically associated with mortality in COVID-19 patients receiving ECMO in the ICU.

CCN2-induced lymphangiogenesis is mediated by the integrin αvß5-ERK pathway and regulated by DUSP6.

Lymphangiogenesis is essential for the development of the lymphatic system and is important for physiological processes such as homeostasis, metabolism and immunity. Cellular communication network factor 2 (CCN2, also known as CTGF), is a modular and matricellular protein and a well-known angiogenic factor in physiological and pathological angiogenesis. However, its roles in lymphangiogenesis and intracellular signaling in lymphatic endothelial cells (LECs) remain unclear. Here, we investigated the effects of CCN2 on lymphangiogenesis. In in vivo Matrigel plug assays, exogenous CCN2 increased the number of Podoplanin-positive vessels. Subsequently, we found that CCN2 induced phosphorylation of ERK in primary cultured LECs, which was almost completely inhibited by the blockade of integrin αvß5 and partially decreased by the blockade of integrin αvß3. CCN2 promoted direct binding of ERK to dual-specific phosphatase 6 (DUSP6), which regulated the activation of excess ERK by dephosphorylating ERK. In vitro, CCN2 promoted tube formation in LECs, while suppression of Dusp6 further increased tube formation. In vivo, immunohistochemistry also detected ERK phosphorylation and DUSP6 expression in Podoplanin-positive cells on CCN2-supplemented Matrigel. These results indicated that CCN2 promotes lymphangiogenesis by enhancing integrin αvß5-mediated phosphorylation of ERK and demonstrated that DUSP6 is a negative regulator of excessive lymphangiogenesis by CCN2.

Combinational Anti-tumor Effects of Chemicals from Paeonia lutea Leaf Extract in Oral Squamous Cell Carcinoma Cells.

AIM: We identified chemical components that exhibited antitumor activity against oral squamous cell carcinoma (OSCC) cells and examined their effective concentrations and additive and/or synergistic effects in combinational usage on the proliferation, apoptosis and cell cycle of OSCC cells. MATERIALS AND METHODS: Using high-performance liquid chromatography, nuclear magnetic resonance spectroscopy and electrospray ionization-mass spectrometry, we identified the main chemical components of the methanol extracts from Paeonia lutea. We investigated the pharmaceutical effects of those components on the proliferation, apoptosis, and cell cycle of an OSCC cell line, SAS, using the tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and caspase assays, as well as flow cytometry cell cycle analysis. We also examined the effects of those components on the mitogen-activated protein kinase signal transduction pathway by western blotting. Finally, the effects on normal human epidermal keratinocyte cells were also examined in similar experiments. RESULTS: Three chemicals have been identified in P. lutea leaves using high performance liquid chromatography: gallic acid methyl ester (GAME), pentagalloyl glucose (PGG) and paeoniflorin (PF). Both GAME and PGG significantly suppressed cell proliferation, and their combined effects were synergistic, while the effect of PF was minimal. However, those chemicals did not induce apoptosis. Cell cycle and western blotting analysis showed that the suppressive effects on cell proliferation resulted from G2 arrest and the suppression of phosphorylation of Akt/PKB. No effect was identified on normal human epidermal keratinocyte cells. CONCLUSION: These results indicate that GAME and PGG are the main chemical components of P. lutea leaves that have potential anti-cancer therapeutic effects.

Effect of chronic kidney disease on the association between hyperuricemia and new-onset hypertension in the general Japanese population: ISSA-CKD study.

We aimed to investigate the association between serum uric acid (SUA) level and development of hypertension as well as the interaction effect of chronic kidney disease (CKD) on this relationship in the general Japanese population. We included 7895 participants aged ≥30 years from the ISSA-CKD study, a population-based retrospective cohort study that used annual health check-up data of residents from Iki Island, Japan. After the exclusion of 1881 with l < 1-year follow-up, 2812 with hypertension at baseline, and 165 with missing information on SUA, a total of 3037 participants were enrolled in this analysis. Participants were divided into four groups according to the quartiles of SUA level at baseline, and multivariable-adjusted hazard ratios for new-onset hypertension were calculated. Stratified analyses were performed for each subgroup (defined by sex, age, alcohol intake, and CKD) to assess the interaction effects. During a mean follow-up period of 4.4 years, 943 participants developed hypertension. The first quartile group was set as the reference group, and the multivariable-adjusted hazard ratios (95% confidence interval) for new-onset hypertension were 1.11 (0.90-1.36) in the second quartile, 1.25 (1.02-1.54) in the third quartile, and 1.35 (1.07-1.70) in the fourth quartile compared with those in the reference group (p = .007 for trend). The stratified analyses showed that the association between SUA and hypertension was significantly stronger in participants with CKD than in those without CKD (p = .035 for interaction). SUA level is an independent risk factor for new-onset hypertension. This tendency was significantly stronger in participants with CKD.

Eating before bed and new-onset hypertension in a Japanese population: the Iki city epidemiological study of atherosclerosis and chronic kidney disease.

The aim of this study was to determine the relationship between eating before bed and the development of hypertension in a general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data collected from the residents of Iki City, Nagasaki Prefecture, Japan. In total, 2930 participants without hypertension at baseline (mean age 57.0 years, male 42.8%) were included in the present analysis. Eating before bed was defined as eating within 2 h of bedtime. The outcome of this study was incident hypertension (blood pressure ≥140/90 mmHg or initiation of blood pressure-lowering medications). Multivariable-adjusted hazard ratios and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. During an average follow-up of 4.5 years, 909 participants developed hypertension. The incidence (per 1000 person-years) of hypertension in the group of individuals who ate before bed was 82.8, whereas that in the group of individuals who did not eat before bed was 65.8. The association was significant even after adjusting for other risk factors, including age, sex, current smoking status, current alcohol intake, regular exercise, obesity, elevated blood pressure, diabetes mellitus, and dyslipidemia, with a hazard ratio of 1.23 (95% CI: 1.05-1.44) for the group of individuals who ate before bed compared with the group of individuals who did not eat before bed (P = 0.01 for trend). Eating before bed was correlated with a future risk of developing hypertension in the general Japanese population.

Effects of soybean meal supplementation on ruminal kinetics of feed particle size reduction and passage in dairy cows fed rice straw.

Six ruminal-cannulated nonlactating Holstein Friesian cows (mean body weight:660 ± 42.9 kg) were used to investigate the effect of soybean meal (SBM) supplementation on voluntary rice straw (RS) intake, feed particle size reduction, and passage kinetics in the rumen. They were allocated to two dietary treatments: RS alone or RS supplemented with SBM. Voluntary dry matter intake of RS and total tract fiber digestibility was increased by SBM supplementation (p < 0.05). Supplementation with SBM decreased rumination time per dietary dry matter (DM) and neutral detergent fiber (NDFom) intake (p < 0.01). Particle size distribution in the rumen and total ruminal NDFom digesta weights were not affected by SBM supplementation. However, the disappearance rates of total digesta and large and small particles from the rumen were increased by SBM supplementation (p < 0.01). Moreover, SBM supplementation increased the rate of size reduction in ruminal particles (p < 0.05). In situ disappearance of DM and NDFom of RS in the rumen was greater in SBM-supplemented cows than in nonsupplemented cows (p < 0.05). This study clearly showed that increased ruminal RS particle size reduction, passage, and fermentation due to SBM supplementation accelerated the RS particle clearance from the rumen and resulted in increased voluntary RS intake of dairy cows.

Regional differences in the fatty acid composition, and vitamin and carotenoid concentrations in farm bulk milk in Hokkaido, Japan.

In this study, we investigated the regional differences in the composition of farm bulk milk produced at three different dairy areas in Hokkaido, Japan. A field survey was conducted at Central, Tokachi, and North areas of Hokkaido, three or four times a year. At each farm, an interview questionnaire for farm basal data was conducted, and 500 ml of bulk tank milk sample was obtained. Fatty acid composition, and vitamin and carotenoid concentrations in the milk samples were determined. In Central and Tokachi areas, corn silage was used as the main forage. In North area, fresh herbage was the dominant feed in the summer season, and grass hay was the main feed in the winter season. Discriminant analysis revealed that the composition of milk samples differed among the areas and seasons. Milk from Central and Tokachi areas contained a higher ratio of linoleic acid compared with that from North area, but there were only slight differences in the composition of milk between Central and Tokachi areas. The concentrations of carotenoids and α-tocopherol were higher in samples from North area and the ratios of trans-vaccenic acid and conjugated linoleic acid were higher in the summer season than in the indoor season.

Eating Speed and Incidence of Diabetes in a Japanese General Population: ISSA-CKD.

BACKGROUND: We investigated whether eating speed was associated with the incidence of diabetes in a Japanese general population. METHODS: A total of 4853 Japanese individuals without diabetes at baseline were analyzed. Self-reported eating speed was categorized as slow, medium, and fast on the basis of questionnaire responses. The study outcome was the incidence of diabetes. RESULTS: After an average follow-up period of 5.1 years, 234 individuals developed diabetes. The incidence of diabetes per 1000 person-years was 4.9 in the slow eating speed group, 8.8 in the medium eating speed group, and 12.5 in the fast eating speed group, respectively (*** p < 0.001 for trend). The HRs were 1.69 (95%CI 0.94-3.06) for the medium eating speed and 2.08 (95%CI 1.13-3.84) for the fast eating speed, compared to the slow eating speed (* p = 0.014 for trend) after adjustment for age, gender, smoking status, drinking, exercise, obesity, hypertension, and dyslipidemia. CONCLUSION: Faster eating speed increased a risk for the incidence of diabetes in a general Japanese population.

Amplification-free gene expression analysis of formalin-fixed paraffin-embedded samples using scanning single-molecule counting.

In this paper, we present the applications of our newly developed, highly sensitive fluorescent detection method referred to as scanning single-molecule counting (SSMC). We found that the target RNA added to the total RNA was detected with high sensitivity at 384 aM by combining a magnetic bead-based assay and SSMC (MB-BA + SSMC). Gene expression analysis without reverse transcription or amplification confirmed that the pattern of gene expression was identical to that of real-time polymerase chain reaction (PCR). MB-BA + SSMC was also applied to formalin-fixed paraffin-embedded (FFPE) samples. RNA fragmentation and crosslinking owing to FFPE processing slightly affected gene expression. Conversely, FFPE samples showed an increase in gene Ct values and a decrease in the number of detectable genes when analyzed using real-time PCR. Overall, our results suggested that SSMC is a powerful tool for target RNA detection and amplification-free gene expression analysis.

White blood cell count and incidence of hypertension in the general Japanese population: ISSA-CKD study.

OBJECTIVES: This study aimed to clarify the relationship between the white blood cell (WBC) count and hypertension in the general Japanese population. METHODS: We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 2935 participants without hypertension at baseline were included in the present analysis. WBC counts were classified as tertile 1 (<4700/µL), tertile 2 (4700-5999/µL), and tertile 3 (≥6000/µL). The outcome was incident hypertension (blood pressure ≥140 mmHg). Multivariable-adjusted hazard ratios and 95% confidence intervals (95% CIs) were estimated using the Cox proportional hazards model. RESULT: During an average follow-up of 4.5 years, 908 participants developed hypertension. The incidence (per 100 person-years) of hypertension increased with an elevation in the WBC count (6.3 in tertile 1, 7.0 in tertile 2, and 7.4 in tertile 3). This association was significant, even after adjustment for other risk factors, including age, sex, current smoking habits, current alcohol intake, exercise habits, obesity, elevated blood pressure, diabetes mellitus, and dyslipidemia. The hazard ratios were 1.07 for tertile 2 (95% CI 0.90-1.26) and 1.27 for tertile 3 (95% CI 1.06-1.51) compared with the reference group of tertile 1 (p = 0.009). CONCLUSION: The WBC count was associated with future development of hypertension in the general Japanese population.

Oral Health of COVID-19 Patients Using Extracorporeal Membrane Oxygenation: A Clinical Study of 19 Cases.

The oral health of coronavirus disease 2019 (COVID-19) patients in the intensive care unit (ICU) is an important issue in treatment of respiratory failure. We retrospectively investigated the oral health history of severe COVID-19 patients who received extracorporeal membrane oxygenation (ECMO) from April 2020 to December 2020 using the oral assessment guide from Fukuoka University (OAG-F). Nineteen consecutive patients (median age: 62 years) were divided into two groups according to survival (survivors, n = 12; non-survivors, n = 7). A univariate analysis revealed no significant differences between the groups in sex, age, body mass index (BMI), or the number of remaining teeth, whereas the ECMO assistance of non-survivors (median: 34 days) was prolonged in comparison to survivors (median: 8 days; p < 0.05). Among the factors of OAG-F, significant differences were observed between the groups in the conditions of the saliva, mucous membrane, and gingiva. The total scores in non-survivors (median: 19) were significantly higher in comparison to survivors (Median: 15.5), suggesting that the frequency of oral health deterioration was higher in non-survivors (p < 0.05). Taken together, these findings suggest that poor oral health is associated with mortality in COVID-19 patients receiving ECMO in the ICU.

Scanning single-molecule counting system for Eprobe with highly simple and effective approach.

Here, we report a rapid and ultra-sensitive detection technique for fluorescent molecules called scanning single molecular counting (SSMC). The method uses a fluorescence-based digital measurement system to count single molecules in a solution. In this technique, noise is reduced by conforming the signal shape to the intensity distribution of the excitation light via a circular scan of the confocal region. This simple technique allows the fluorescent molecules to freely diffuse into the solution through the confocal region and be counted one by one and does not require statistical analysis. Using this technique, 28 to 62 aM fluorescent dye was detected through measurement for 600 s. Furthermore, we achieved a good signal-to-noise ratio (S/N = 2326) under the condition of 100 pM target nucleic acid by only mixing a hybridization-sensitive fluorescent probe, called Eprobe, into the target oligonucleotide solution. Combination of SSMC and Eprobe provides a simple, rapid, amplification-free, and high-sensitive target nucleic acid detection system. This method is promising for future applications to detect particularly difficult to design primers for amplification as miRNAs and other short oligo nucleotide biomarkers by only hybridization with high sensitivity.