179 research outputs found
Quantum Cryptography without Public Announcement of Bases
This paper provides a simple variation of the basic ideas of the BB84 quantum
cryptographic scheme leading to a method of key expansion. A secure random
sequence (the bases sequence) determines the encoding bases in a proposed
scheme. Using the bases sequence repeatedly is proven to be safe by quantum
mechanical laws.Comment: 4 page
Application and evaluation of the MLVA typing assay for the Brucella abortus strains isolated in Korea
<p>Abstract</p> <p>Background</p> <p>A Brucella eradication program has been executed in Korea. To effectively prevent and control brucellosis, a molecular method for genetic identification and epidemiological trace-back must be established. As part of that, the MLVA typing assay was evaluated and applied to <it>B. abortus </it>isolates for analyzing the characteristics of the regional distribution and relationships of foreign isolates.</p> <p>Results</p> <p>A total of 177 isolates originating from 105 cattle farms for the period 1996 to 2008 were selected as representatives for the nine provinces of South Korea. A dendrogram of strain relatedness was constructed in accordance with the number of tandem repeat units for 17 loci so that it was possible to trace back in the restricted areas. Even in a farm contaminated by one source, however, the <it>Brucella </it>isolates showed an increase or decrease in one TRs copy number at some loci with high DI values. Moreover, those 17 loci was confirmed in stability via <it>in-vitro </it>and <it>in-vivo </it>passage, and found to be sufficiently stable markers that can readily identify the inoculated strain even if minor changes were detected. In the parsimony analysis with foreign <it>Brucella </it>isolates, domestic isolates were clustered distinctively, and located near the Central and Southern American isolates.</p> <p>Conclusion</p> <p>The MLVA assay has enough discrimination power in the <it>Brucella </it>species level and can be utilized as a tool for the epidemiological trace-back of the <it>B. abortus </it>isolates. But it is important to consider that <it>Brucella </it>isolates may be capable of undergoing minor changes at some loci in the course of infection or in accordance with the changes of the host.</p
Expression of Keratin 10 in Rat Organ Surface Primo-vascular Tissues
AbstractThe primo-vascular system is described as the anatomical structure corresponding to acupuncture meridians and has been identified in several tissues in the body, but its detailed anatomy and physiology are not well understood. Recently, the presence of keratin 10 (Krt10) in primo-vascular tissue was reported, but this finding has not yet been confirmed. In this study, we compared Krt10 expression in primo-vascular tissues located on the surface of rat abdominal organs with Krt10 expression on blood and lymphatic vessels. Krt10 protein (approximately 56.5 kDa) was evaluated by western blot analysis and immunohistochemistry. Krt10 (IR) in the primo-node was visualized as patchy spots around each cell or as a follicle-like structure containing a group of cells. Krt10 IR was also identified in vascular and lymphatic tissues, but its distribution was diffuse over the extracellular matrix of the vessels. Thus Krt10 protein was expressed in all three tissues tested, but the expression pattern of Krt10 in primo-vascular tissue differed from those of blood and lymphatic vascular tissues, suggesting that structural and the regulatory roles of Krt10 in primo-vascular system are different from those in blood and lymphatic vessels
Impact of glycemic control on the progression of aortic stenosis: a single-center cohort study using a common data model
Background
Diabetes mellitus (DM) is a well-established risk factor for the progression of degenerative aortic stenosis (AS). However, no study has investigated the impact of glycemic control on the rate of AS progression. We aimed to assess the association between the degree of glycemic control and the AS progression, using an electronic health record-based common data model (CDM).
Methods
We identified patients with mild AS (aortic valve [AV] maximal velocity [Vpeak] 2.0–3.0 m/sec) or moderate AS (Vpeak 3.0–4.0 m/sec) at baseline, and follow-up echocardiography performed at an interval of ≥ 6 months, using the CDM of a tertiary hospital database. Patients were divided into 3 groups: no DM (n = 1,027), well-controlled DM (mean glycated hemoglobin [HbA1c] < 7.0% during the study period; n = 193), and poorly controlled DM (mean HbA1c ≥ 7.0% during the study period; n = 144). The primary outcome was the AS progression rate, calculated as the annualized change in the Vpeak (△Vpeak/year).
Results
Among the total study population (n = 1,364), the median age was 74 (IQR 65–80) years, 47% were male, the median HbA1c was 6.1% (IQR 5.6–6.9), and the median Vpeak was 2.5 m/sec (IQR 2.2–2.9). During follow-up (median 18.4 months), 16.1% of the 1,031 patients with mild AS at baseline progressed to moderate AS, and 1.8% progressed to severe AS. Among the 333 patients with moderate AS, 36.3% progressed to severe AS. The mean HbA1c level during follow-up showed a positive relationship with the AS progression rate (β = 2.620; 95% confidence interval [CI] 0.732–4.507; p = 0.007); a 1%-unit increase in HbA1c was associated with a 27% higher risk of accelerated AS progression defined as △Vpeak/year values > 0.2 m/sec/year (adjusted OR = 1.267 per 1%-unit increase in HbA1c; 95% CI 1.106–1.453; p < 0.001), and HbA1c ≥ 7.0% was significantly associated with an accelerated AS progression (adjusted odds ratio = 1.524; 95% CI 1.010–2.285; p = 0.043). This association between the degree of glycemic control and AS progression rate was observed regardless of the baseline AS severity.
Conclusion
In patients with mild to moderate AS, the presence of DM, as well as the degree of glycemic control, is significantly associated with accelerated AS progression
Primary Malignant Pericardial Mesothelioma Presenting as Acute Pericarditis
We report on a 21-year-old man with fever, dyspnea, and pleuritic chest pain. An electrocardiography showed ST elevation in multiple lead and thoracic echocardiography revealed moderate pericardial effusion. He was initially diagnosed with acute pericarditis, and treated with nonsteroidal anti-inflammatory drugs and colchicines with clinical and laboratory improvement. After 1 month of medication, his symptoms recurred. An echocardiography showed constrictive physiology and the patient was treated with steroid on the top of current medication. The patient had been well for 7 months until dyspnea and edema developed, when an echocardiography showed marked increased pericardial thickness and constriction. Pericardial biopsy was performed and primary malignant pericardial mesothelioma was diagnosed. Malignancy should be considered in the differential diagnosis of recurrent pericarditis
Myofilament Ca2+ desensitization mediates positive lusitropic effect of neuronal nitric oxide synthase in left ventricular myocytes from murine hypertensive heart
AbstractNeuronal nitric oxide synthase (NOS1 or nNOS) exerts negative inotropic and positive lusitropic effects through Ca2+ handling processes in cardiac myocytes from healthy hearts. However, underlying mechanisms of NOS1 in diseased hearts remain unclear. The present study aims to investigate this question in angiotensin II (Ang II)-induced hypertensive rat hearts (HP). Our results showed that the systolic function of left ventricle (LV) was reduced and diastolic function was unaltered (echocardiographic assessment) in HP compared to those in shams. In isolated LV myocytes, contraction was unchanged but peak [Ca2+]i transient was increased in HP. Concomitantly, relaxation and time constant of [Ca2+]i decay (tau) were faster and the phosphorylated fraction of phospholamban (PLN-Ser16/PLN) was greater. NOS1 protein expression and activity were increased in LV myocyte homogenates from HP. Surprisingly, inhibition of NOS1 did not affect contraction but reduced peak [Ca2+]i transient; prevented faster relaxation without affecting the tau of [Ca2+]i transient or PLN-Ser16/PLN in HP, suggesting myofilament Ca2+ desensitization by NOS1. Indeed, relaxation phase of the sarcomere length–[Ca2+]i relationship of LV myocytes shifted to the right and increased [Ca2+]i for 50% of sarcomere shortening (EC50) in HP. Phosphorylations of cardiac myosin binding protein-C (cMyBP-C282 and cMyBP-C273) were increased and cardiac troponin I (cTnI23/24) was reduced in HP. Importantly, NOS1 or PKG inhibition reduced cMyBP-C273 and cTnI23/24 and reversed myofilament Ca2+ sensitivity. These results reveal that NOS1 is up-regulated in LV myocytes from HP and exerts positive lusitropic effect by modulating myofilament Ca2+ sensitivity through phosphorylation of key regulators in sarcomere
Different effects of SGLT2 inhibitors according to the presence and types of heart failure in type 2 diabetic patients
Background
The effects of sodium-glucose cotransporter 2 inhibitor (SGLT2i) on cardiac function are not fully understood. We investigated the changes in cardiac function in diabetic patients according to the presence and types of heart failure (HF).
Methods
We retrospectively identified 202 diabetic patients who underwent echocardiography before, and 6 to 24 months after the initiation of SGLT2i. After propensity score matching with diabetic patients without SGLT2i, the study population (n = 304) were categorized into group 1 (without HF nor SGLT2i; n = 76), group 2 (without HF and received SGLT2i; n = 78), group 3 (with HF but without SGLT2i; n = 76), and group 4 (with HF and received SGLT2i; n = 74). Changes in echocardiographic parameters were compared between these 4 groups, and between HF patients with reduced versus preserved ejection fraction (EF).
Results
After a median 13 months of follow-up, HF patients with SGLT2i showed a significant decrease in left ventricular end-diastolic dimension (LV-EDD; from 57.4 mm [50.0–64.9] to 53.0 mm [48.0–60.0]; p < 0.001) and improvement in LV-EF (from 36.1% [25.6–47.5] to 45.0% [34.8–56.3]; p < 0.001). LV mass index and diastolic parameters also showed improvements in HF patients with SGLT2i. The SGLT2i-induced improvements in cardiac function were more prominent in HF patients than those without HF, and in HFrEF patients than HFpEF patients.
Conclusions
Use of SGLT2i improved cardiac function in diabetic patients, regardless of the presence of HF. The improvements were more prominent in HF patients, especially in those with HFrEF. These improvements in cardiac function would contribute to the clinical benefit of SGLT2i
Healthcare utilization, medical expenditure, and mortality in Korean patients with pulmonary hypertension
Background
Limited data exists regarding healthcare utilization, medical expenses, and prognosis of pulmonary hypertension (PH) according to the World Health Organization (WHO) classification. We aimed to investigate mortality risk, healthcare utilization and medical expenditure in patients with PH across the five diagnostic subgroups.
Methods
We identified 2185 patients with PH, defined as peak tricuspid regurgitation velocity > 3.4 m/sec, among the consecutive patients referred for echocardiography between 2009 and 2015. Using diagnostic codes, medical records, and echocardiographic findings, the enrolled patients were classified according to the five subgroups by WHO classification. Healthcare utilization, costs, and all-cause mortality were assessed.
Results
Diagnostic subgroups of PH demonstrated significantly different clinical features. During a median of 32.4 months (interquartile range, 16.2–57.8), 749 patients (34.3%) died. Mortality risk was the lowest in group II (left heart disease) and highest in group III (chronic lung disease). The etiologies of pulmonary arterial hypertension (PAH) had significant influence on the mortality risk in group I, showing the worst prognosis in PAH associated with connective tissue disease. Medical expenditure and healthcare utilization were different between the PH subgroups: groups II and V had more hospitalizations and medical expenses than other groups. Regardless of PH subgroups, the severity of PH was associated with higher mortality risk, more healthcare utilization and medical expenditure.
Conclusions
Significant differences in clinical features and prognostic profiles between PH subgroups reflect the differences in pathophysiology and clinical consequences. Our findings highlight the importance of comprehensive understanding of PH according to the etiology and its severity.This study was supported by Seoul National University Bundang Hospital (13–2016-018).This study was supported by Seoul National University Bundang Hospital (13–2016-018)
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