Potential of non-contrast stress T1 mapping for the assessment of myocardial injury in hypertrophic cardiomyopathy.

BACKGROUND: Ischemia of the hypertrophied myocardium due to microvascular dysfunction is related to a worse prognosis in hypertrophic cardiomyopathy (HCM). Stress and rest T1 mapping without contrast agents can be used to assess myocardial blood flow. Herein, we evaluated the potential of non-contrast stress T1 mapping in assessing myocardial injury in patients with HCM. METHODS: Forty-five consecutive subjects (31 HCM patients and 14 control subjects) underwent cardiac magnetic resonance (CMR) at 3T, including cine imaging, T1 mapping at rest and during adenosine triphosphate (ATP) stress, late gadolinium enhancement (LGE), and phase-contrast (PC) cine imaging of coronary sinus flow at rest and during stress to assess coronary flow reserve (CFR). PC cine imaging was performed on 25 subjects (17 patients with HCM and 8 control subjects). Native T1 values at rest and during stress were measured using the 16-segment model, and T1 reactivity was defined as the change in T1 values from rest to stress. RESULTS: ATP stress induced a significant increase in native T1 values in both the HCM and control groups (HCM: p < 0.001, control: p = 0.002). T1 reactivity in the HCM group was significantly lower than that in the control group (4.2 ± 0.3% vs. 5.6 ± 0.5%, p = 0.044). On univariate analysis, T1 reactivity correlated with native T1 values at rest, left ventricular mass index, and CFR. Multiple linear regression analysis demonstrated that only CFR was independently correlated with T1 reactivity (ß = 0.449; 95% confidence interval, 0.048-0.932; p = 0.032). Furthermore, segmental analysis showed decreased T1 reactivity in the hypertrophied myocardium and the non-hypertrophied myocardium with LGE in the HCM group. CONCLUSIONS: T1 reactivity was lower in the hypertrophied myocardium and LGE-positive myocardium compared to non-injured myocardium. Non-contrast stress T1 mapping is a promising CMR method for assessing myocardial injury in patients with HCM. Trial registration Retrospectively registered.

Quantitative comparison of the RNA bacteriophage Qß infection cycle in rich and minimal media.

As bacteriophages are dependent on the host for multiplication, their infection cycle is expected to be influenced by the host's physiological state. To elucidate how and which steps of the bacteriophage infection cycle are influenced by changes in the physiological state of the host, we quantitatively compared the infection cycle of lytic RNA bacteriophage Qß in Escherichia coli cultured in rich and minimal media. The adsorption rate constants in both media were almost the same. A difference of 15 min in the latent period and an approximately twofold increase in the rate of phage release were observed, although approximately 10(5) molecules of coat proteins, equivalent to approximately 600-1000 phage particles, accumulated in an infected cell prior to burst. Addition of Mg(2+) to minimal medium markedly affected the Qß infection cycle, and these results suggest that Mg(2+) is required for the stages of the infectious cycle after adsorption.

Performance of Hybrid Imaging in the Diagnosis of Coronary Artery Disease.

Single-photon emission computed tomography (SPECT) and computed tomography coronary angiography (CTCA) are usually performed independently in patients with suspected coronary artery disease. We assessed the hypothesis that hybrid SPECT/CTCA imaging results in higher diagnostic accuracy than either method alone, particularly in cases presenting with high levels of coronary calcification. A total of 243 major coronary vessels in 81 patients with known or suspected coronary artery disease were screened using SPECT with semiconductor detectors and CTCA with 256-detector row computed tomography. Patients who were diagnosed with myocardial ischemia underwent coronary angiography. Coronary angiography results were defined as positive for stenosis when the stenosis diameter was >70% or fractional flow reserve was <0.8. These data were then compared with a fused image of the SPECT and CTCA datasets generated using a dedicated workstation. To detect significant coronary artery stenosis, the respective sensitivity, specificity, and accuracy were 73%, 61%, and 67% with SPECT alone, 96%, 44%, and 67% with CTCA alone, and 95%, 75%, and 84% with hybrid imaging. Moreover, hybrid imaging allowed the accurate diagnosis of 47 vessels with severe calcification that CTCA alone could not evaluate correctly. Hybrid imaging shows greater diagnostic accuracy than single-modality evaluation through more comprehensive information on potential coronary stenosis and its hemodynamic significance.

Relationship between anti-acetylcholine receptor antibodies and the development of post-thymectomy myasthenia gravis in patients with thymoma: a single-center experience.

BACKGROUND: Approximately 15-29.6% of patients with thymoma have myasthenia gravis (MG). Some of these patients develop MG after thymectomy despite having no history of MG or related symptoms. Few previous studies have examined the risk factors for the development of post-thymectomy MG in patients with thymoma. Herein, we retrospectively reviewed our institutional experience with patients with thymoma who developed MG after thymectomy. METHODS: Twenty-six patients with thymoma but without MG, who were tested preoperatively for anti-acetylcholine receptor antibody (anti-AChR-Ab) levels, underwent surgical resection at our hospital between 2013 and 2020. Patients with thymic carcinoma were excluded from the study. We evaluated the association of outcomes with preoperative anti-AChR-Ab levels and post-thymectomy MG. We performed a χ2 test for bivariate analysis of categorical data. Differences were considered significant at P<0.05. RESULTS: The characteristics of the 26 patients (median age: 62 years; 8 men, 18 women) were as follows: World Health Organization (WHO) classifications AB (n=8), B1 (n=9), B2 (n=6), B3 (n=1), and others (n=2) and Masaoka stage I (n=12), II (n=9), III (n=3), and IVa (n=2). Among the 26 patients, only five had high (>0.3 nmol/L) preoperative anti-AChR-Ab levels. Post-thymectomy MG occurred in two of the five patients (40%) with high preoperative anti-AChR-Ab levels. A high preoperative serum anti-AChR-Ab titer was significantly associated with post-thymectomy MG (P=0.0267). The anti-AChR-Ab titer was also measured postoperatively in four of the five (80%) patients with high preoperative levels. The anti-AChR-Ab titer decreased in two of these four patients, and neither developed postoperative MG. CONCLUSIONS: Preoperative and postoperative anti-AChR-Ab positivity might be associated with post-thymectomy MG. Therefore, regular measurement of anti-AChR-Ab levels after thymectomy is required.

Genome sequence of the cellulosome-producing mesophilic organism Clostridium cellulovorans 743B.

Clostridium cellulovorans 743B was isolated from a wood chip pile and is an anaerobic and mesophilic spore-forming bacterium. This organism degrades native substrates in soft biomass such as corn fiber and rice straw efficiently by producing an extracellular enzyme complex called the cellulosome. Here we report the genome sequence of C. cellulovorans 743B.

Successful Outcome in an Adult Patient with Influenza-associated Hemorrhagic Shock and Encephalopathy Syndrome.

A 50-year-old woman presented with coma and hemorrhagic shock. A rapid influenza antigen test revealed influenza A infection; other laboratory examinations ruled out any other suspected infections. She was diagnosed with hemorrhagic shock and encephalopathy syndrome (HSES) induced by influenza A. She was administered methylprednisolone pulse therapy and peramivir. Subsequently, she was discharged without any sequelae. Only a few cases of influenza-induced HSES have been reported, and the clinical outcomes were very poor. We herein report a successfully treated adult case of influenza-induced HSES and review this rare syndrome.

Efficacy of combined estrogen-progestin hormone contraception therapy for refractory coronary spastic angina in very young women.

Coronary spastic angina (CSA) in premenopausal women is rare, but has also been suggested to be associated with estrogen decline during the menstrual cycle. In this report, we describe the case of a young premenopausal patient with refractory CSA. She presented with ventricular fibrillation (VF) at the age of 15 years and was diagnosed as having CSA. She underwent implantation of an Implantable Cardioverter Defibrillator (ICD), and despite receiving systemic drug therapy at the maximum doses, she experienced a total of four appropriate ICD shocks over the subsequent six years. Based on careful history-taking, it was suspected that the angina episodes were closely related to the phase of the menstrual cycle. We started the patient on continuous combined estrogen-progestin hormone contraception therapy so as to prevent the reduction of the blood estrogen levels just prior to and during menstruation. After the start of this treatment, the patient became completely free of angina episodes. Although there are a few reports of the efficacy of hormone replacement therapy in premenopausal women with CSA, this is the first report of the efficacy of this therapy in a woman as young as 22 years old. .

Growth of Alicyclobacillus acidoterrestris in the Hypoxic Environment of Bottled Fruit Juice.

Alicyclobacillus acidoterrestris, an obligate aerobe and one of the most harmful bacteria in acidic beverages, requires oxygen for growth. However, the relationship between oxygen availability and its growth has not yet been quantified. We examined the correlation between A. acidoterrestris growth and oxygen availability to determine whether A. acidoterrestris can be controlled by restricting oxygen. Airtight containers were filled with YSG broth and apple juice at various oxygen concentrations. Positive correlation (R(2)=0.9329) was observed between A. acidoterrestris growth and oxygen availability in YSG broth, and a lower but nonetheless slight correlation (R(2)=0.5604) was observed for apple juice. These results indicate that decreased oxygen availability in a container could restrict growth. As results, the addition of reducing compounds along with airtight conditions may help prevent the deterioration of beverages caused by the proliferation of A. acidoterrestris.