Dobutamine stress cardiovascular magnetic resonance at 3 Tesla

<p>Abstract</p> <p>Purpose</p> <p>The assessment of inducible wall motion abnormalities during high-dose dobutamine-stress cardiovascular magnetic resonance (DCMR) is well established for the identification of myocardial ischemia at 1.5 Tesla. Its feasibility at higher field strengths has not been reported. The present study was performed to prospectively determine the feasibility and diagnostic accuracy of DCMR at 3 Tesla for depicting hemodynamically significant coronary artery stenosis (≥ 50% diameter stenosis) in patients with suspected or known coronary artery disease (CAD).</p> <p>Materials and methods</p> <p>Thirty consecutive patients (6 women) (66 ± 9.3 years) were scheduled for DCMR between January and May 2007 for detection of coronary artery disease. Patients were examined with a Philips Achieva 3 Tesla system (Philips Healthcare, Best, The Netherlands), using a spoiled gradient echo cine sequence. Technical parameters were: spatial resolution 2 × 2 × 8 mm³, 30 heart phases, spoiled gradient echo TR/TE: 4.5/2.6 msec, flip angle 15°. Images were acquired at rest and stress in accordance with a standardized high-dose dobutamine-atropine protocol during short breath-holds in three short and three long-axis views. Dobutamine was administered using a standard protocol (10 μg increments every 3 minutes up to 40 μg dobutamine/kg body weight/minute plus atropine if required to reach target heart rate). The study protocol included administration of 0.1 mmol/kg/body weight Gd-DTPA before the cine images at rest were acquired to improve the image quality. The examination was terminated if new or worsening wall-motion abnormalities or chest pain occurred or when > 85% of age-predicted maximum heart rate was reached. Myocardial ischemia was defined as new onset of wall-motion abnormality in at least one segment. In addition, late gadolinium enhancement (LGE) was performed. Images were evaluated by two blinded readers. Diagnostic accuracy was determined with coronary angiography as the reference standard. Image quality and wall-motion at rest and maximum stress level were evaluated using a four-point scale.</p> <p>Results</p> <p>In 27 patients DCMR was performed successfully, no patient had to be excluded due to insufficient image quality. Twenty-two patients were examined by coronary angiography, which depicted significant stenosis in 68.2% of the patients. Patient-based sensitivity and specificity were 80.0% and 85.7% respectively and accuracy was 81.8%. Interobserver variability for assessment of wall motion abnormalities was 88% (κ = 0.760; p < 0.0001). Negative and positive predictive values were 66.7% and 92.3%, respectively. No significant differences in average image quality at rest versus stress for short or long-axis cine images were found.</p> <p>Conclusion</p> <p>High-dose DCMR at 3T is feasible and an accurate method to depict significant coronary artery stenosis in patients with suspected or known CAD.</p

4-Phenylbutyric acid treatment rescues trafficking and processing of a mutant surfactant protein C

Mutations in the SFTPC gene, encoding surfactant protein–C (SP-C), are associated with interstitial lung disease (ILD). Knowledge of the intracellular fate of mutant SP-C is essential in the design of therapies to correct trafficking/processing of the proprotein, and to prevent the formation of cytotoxic aggregates. We assessed the potential of a chemical chaperone to correct the trafficking and processing of three disease-associated mutant SP-C proteins. HEK293 cells were stably transfected with wild-type (SP-C(WT)) or mutant (SP-C(L188Q), SP-C(Δexon4), or SP-C(I73T)) SP-C, and cell lines with a similar expression of SP-C mRNA were identified. The effects of the chemical chaperone 4-phenylbutyric acid (PBA) and lysosomotropic drugs on intracellular trafficking to the endolysosomal pathway and the subsequent conversion of SP-C proprotein to mature peptide were assessed. Despite comparable SP-C mRNA expression, proprotein concentrations varied greatly: SP-C(I73T) was more abundant than SP-C(WT) and was localized to the cell surface, whereas SP-C(Δexon4) was barely detectable. In contrast, SP-C(L188Q) and SP-C(WT) proprotein concentrations were comparable, and a small amount of SP-C(L188Q) was localized to the endolysosomal pathway. PBA treatment restored the trafficking and processing of SP-C(L188Q) to SP-C(WT) concentrations, but did not correct the mistrafficking of SP-C(I73T) or rescue SP-C(Δexon4). PBA treatment also promoted the aggregation of SP-C proproteins, including SP-C(L188Q). This study provides proof of the principle that a chemical chaperone can correct the mistrafficking and processing of a disease-associated mutant SP-C proprotein

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Not AvailableAn efficient protocol for shoot bud induction and proliferation employing half cotyledonary node with intact cotyledon explants derived from two-day-old seedlings of mung bean pre-conditioned on 6- benzylaminopurine (BAP) has been achieved. Explants were cultured for four weeks each on MS B5 + 12.5 μM BAP and MS B5 + 5 μM BAP +0.05 μM α- naphthaleneacetic acid (NAA ), respectively, as shoot bud induction and shoot elongation and proliferation media, gave the best regeneration response. The removal of the pre-existing buds from explants at 12 days in shoot bud induction medium led to enhanced regeneration response. Light microscopic observations on 14-day-old explants confirmed direct organogenesis route of regeneration. Elongated shoots (>2 cm) excised from the regenerating cultures were successfully rooted on half MS B5 medium containing 2.46 μM indolebutyric acid (IBA). About 90% of the rooted plantlets, efficiently hardened in pots having soil and farm yard manure, flowered and produced pods with viable seeds upon reaching maturity.Not Availabl

A Study on the Effectiveness & Challenges of Online Classes for Teachers and Students

Education can be broadly described as an all-round process encapsulating the information on varied topics that are necessary for the learner to know, understand and practice for the benefit of self and society.&nbsp; The process necessarily involves a teacher who imparts the required knowledge and the seeker of knowledge (student) who is bestowed with the required knowledge by the teacher.&nbsp;Dictionary meaning of Education - ‘a process of teaching, training, and learning, especially in schools or colleges, to improve knowledge and develop skills[i] Online or remote learning or training is necessary, and it is common in case of distance learning programs. Whereas, in these days particularly during the lockdown period (i.e. tentatively from March 2020) almost all educational institutions from schools, colleges, and universities have been focusing their vision on online training to their students. Before the pandemic situation, most of these institutions do not have the online teaching experience (either to a teacher or students), though they have been well equipped with internet and technology usage. It means that the situation is not demanded to go away from face-face or classroom teaching.&nbsp; Generally, a situation or scenario will bring some challenges to the direct parties (a teacher and student), and indirect parties administrators, other stakeholders (parents, technology services providers/suppliers). With this in the background, the researcher has conducted this study to understand the nuances of online classes and find the effectiveness with which the online classes are being conducted for various levels of students. For this study, an online questionnaire was prepared and sent to two categories of respondents – Teachers &amp; Students, who are part of these online classes.[i]https://www.oxfordlearnersdictionaries.com/definition/american_english/education, accessed on 30th July 202

Impaired left ventricular stroke volume reserve during clinical dobutamine stress predicts future episodes of pulmonary edema.

OBJECTIVES: The purpose of this study was to determine whether dobutamine-induced abnormal stress changes in left ventricular stroke volume (LVSV) and aortic stiffness predict future pulmonary edema. BACKGROUND: Increased aortic stiffness that decreases LVSV during adrenergic stress may serve as a marker for future pulmonary edema (PE). METHODS: We measured LVSV, ventriculovascular stiffness (pulse pressure/LVSV(index)), and aortic distensibility at rest and during intravenous dobutamine administration using cardiovascular magnetic resonance. Personnel blinded to dobutamine cardiovascular magnetic resonance followed participants longitudinally over time to identify those admitted to the hospital with PE. Data for 44 participants who had a hospital admission for PE were compared with data for 72 participants of similar age, sex, and resting left ventricular ejection fraction who remained PE free. RESULTS: Expressed as median and interquartile range, participants with and without PE exhibited a decreased stress/rest LVSV ratio (0.9 [range 0.7 to 1.1] vs. 1.0 [range 0.9 to 1.2], respectively; p = 0.002), an increased ventriculovascular stiffness stress/rest ratio (1.4 [range 1.0 to 1.6] vs. 1.0 [range 0.8 to 1.3], respectively; p ≤ 0.001); and a decreased stress-induced measure of aortic distensibility (0.8 mm Hg(-3) [range 0.3 to 1.3 mm Hg(-3)] vs. 1.6 mm Hg(-3) [range 1.2 to 3.2 mm Hg(-3)], respectively; p = 0.002). After accounting for age, sex, left ventricular ejection fraction, risk factors for PE, and the presence of dobutamine-induced ischemia, LVSV reserve and the stress/rest ventriculovascular stiffness ratio still differed (p &lt; 0.008 for both) in those with and without PE. CONCLUSIONS: In patients without inducible ischemia during dobutamine stress testing in whom one might otherwise assume a favorable prognosis, the failure to increase LVSV or an increase in ventriculovascular stiffness indicates patients at risk of subsequent PE

Prediction of cardiac events in patients with reduced left ventricular ejection fraction with dobutamine cardiovascular magnetic resonance assessment of wall motion score index.

OBJECTIVES: The purpose of this study was to assess the utility of dobutamine cardiovascular magnetic resonance (DCMR) results for predicting cardiac events in individuals with reduced left ventricular ejection fraction (LVEF). BACKGROUND: It is unknown whether DCMR results identify a poor cardiac prognosis when the resting LVEF is moderately to severely reduced. METHODS: Two hundred consecutive patients ages 30 to 88 (average 64) years with an LVEF 40%. CONCLUSIONS: In individuals with mild to moderate reductions in LVEF (40% to 55%), dobutamine-induced increases in WMSI forecast MI and cardiac death to a greater extent than an assessment of resting LVEF. In those with an LVEF &lt;40%, a dobutamine-induced increase in WMSI does not predict MI and cardiac death beyond the assessment of resting LVEF.</or=55%