Quantitative mapping of cerebral deoxyhemoglobin content using MR imaging

In this study, we present a magnetic resonance imaging (MRI) method for quantifying cerebral deoxyhemoglobin content that is based on a measurement of the reversible contribution (R'2) of the transverse relaxation rate under the assumption of a quantitative relationship between R'2 and deoxyhemoglobin content. A numerical simulation was performed assuming a specific pulse sequence conventionally employed for R'2 measurement. The results showed a near linear relationship between R'2 and deoxyhemoglobin content in the physiological range of oxygen extraction for almost all sized vessels, although a large diffusion effect for capillary sized vessels compromised the relationship. Concerning the methodology for R'2 measurement, a theoretical analysis showed that multiexponential transverse signal decay of brain parenchyma may result in a considerable underestimation or overestimation of R'2, if a conventional method is employed for R'2 quantification. A modified method for correcting the effect of multiexponential signal decay was employed for R'2 measurement of the brain in normal volunteers. The results showed a high level of agreement between the R'2 values measured in our study and those estimated from physiological parameters obtained using other modalities such as PET. In the context of BOLD contrast-based functional MRI, the method proposed provides a quantitative mapping of baseline cerebral deoxyhemoglobin content, which is the essential physiological parameter for calibrating the stimulation-induced BOLD signal change and mapping neuronal activity in a quantitative manner by functional MRI.     

Patents related to the treatment and diagnosis of bruxism

Introduction: Bruxism is among the most chronic dental problems worldwide, and its perception may increase indicatively the condition of people’s health, avoiding future health problems. Technologic solutions have improved considerably owing to new diagnostic and treatment technologies and their automation. This review aims to assess therapeutic methods for bruxism through analysis of patent applications spanning recent decades.

Areas covered: Patent families of bruxism, and products available on the market. Data were obtained through Questel Orbit from the European Patent Office on a worldwide basis using Cooperative Patent Classification (CPC), analyzing 134 patent families. The products on the market were mapped and classified as used for diagnosis, treatment, or both.

Expert opinion: This technological prospect has shown that the technological field of bruxism is growing toward smaller, automated devices; there is still no predominant owner of the technologies. Products are expected to provide home use with a high degree of reliability and specificity, using the Internet of Things (telemedicine associated with industry 4.0) and enabling real-time diagnosis.     

Association between Vitamin D and Heart Failure Mortality in 10,974 Hospitalized Individuals

A broad range of chronic conditions, including heart failure (HF), have been associated with vitamin D deficiency. Existing clinical trials involving vitamin D supplementation in chronic HF patients have been inconclusive. We sought to evaluate the outcomes of patients with vitamin D supplementation, compared with a matched cohort using real-world big data of HF hospitalization. This study was based on the Diagnosis Procedure Combination database in the Japanese Registry of All Cardiac and Vascular Datasets (JROAD-DPC). After exclusion criteria, we identified 93,692 patients who were first hospitalized with HF between April 2012 and March 2017 (mean age was 79 ± 12 years, and 52.2% were male). Propensity score (PS) was estimated with logistic regression model, with vitamin D supplementation as the dependent variable and clinically relevant covariates. On PS-matched analysis with 10,974 patients, patients with vitamin D supplementation had lower total in-hospital mortality (6.5 vs. 9.4%, odds ratio: 0.67, p < 0.001) and in-hospital mortality within 7 days and 30 days (0.9 vs. 2.5%, OR, 0.34, and 3.8 vs. 6.5%, OR: 0.56, both p < 0.001). In the sub-group analysis, mortalities in patients with age < 75, diabetes, dyslipidemia, atrial arrhythmia, cancer, renin-angiotensin system blocker, and β-blocker were not affected by vitamin D supplementation. Patients with vitamin D supplementation had a lower in-hospital mortality for HF than patients without vitamin D supplementation in the propensity matched cohort. The identification of specific clinical characteristics in patients benefitting from vitamin D may be useful for determining targets of future randomized control trials.     

Long-term inhibition of Rho-kinase ameliorates diastolic heart failure in hypertensive rats

Diastolic heart failure (DHF) is a major cardiovascular disorder with poor prognosis; however, its molecular mechanism still remains to be fully elucidated. We have previously demonstrated the important roles of Rho-kinase pathway in the molecular mechanisms of cardiovascular fibrosis/hypertrophy and oxidative stress, but not examined in the development of heart failure. Therefore, we examined in this study whether Rho-kinase pathway is also involved in the pathogenesis of DHF in Dahl salt-sensitive rats, an established animal model of DHF. They were maintained with or without fasudil, a Rho-kinase inhibitor (30 or 100 mg/kg/day, PO) for 10 weeks. Untreated DHF group exhibited overt heart failure associated with diastolic dysfunction but with preserved systolic function, characterized by increased myocardial stiffness, cardiomyocyte hypertrophy, and enhanced cardiac fibrosis and superoxide production. Fasudil treatment significantly ameliorated those DHF-related myocardial changes. Western blot analysis showed that cardiac Rho-kinase activity was significantly increased in the untreated DHF group and was dose-dependently inhibited by fasudil. Importantly, there was a significant correlation between the extent of myocardial stiffness and that of cardiac Rho-kinase activity. These results indicate that Rho-kinase pathway plays an important role in the pathogenesis of DHF and thus could be an important therapeutic target for the disorder.     

Assessment of time-resolved, dynamic, contrast-enhanced MRDSA using radial sliding-window reconstruction.

Sliding-window reconstruction (SWR) has been recently introduced for rapid imaging that improves temporal resolution while maintaining signal-to-noise ratio (SNR) and spatial resolution. We assessed the quantity of 2-dimensional contrast-enhanced magnetic resonance digital subtraction angiography (2D CE-MRDSA) with non-Cartesian radial SWR in phantom and clinical studies. In phantoms, we compared the quantitative properties of time-intensity curves (TIC) obtained with dynamic 2D CE-MRDSA using SWR in a radial acquisition with those obtained by Cartesian acquisition. We calculated the mean variance and standard deviation among signal intensities in TICs and used SWR to study 2D CE-MRDSA in 5 patients with angiographically proven arteriovenous malformations. Using a 3-point grading scale, we individually scored vascular visualization capability and calculated time delay (TD) from the TIC in the feeding artery (FA), nidus, and draining vein (DV). The maximum signal intensity variance in Cartesian SWR was 6.58 +/- 2.27% among time-intensity curves and was 0.87 +/- 0.77% radial SWR. Signal intensity in radial SWR decreased significantly (P<0.001) compared with the Cartesian SWR. In clinical study, the mean rating on 2D CE-MRA of the feeding artery was 2.3, nidus, 2.6, and draining vein, 2.6. Mean delay time between DV and FA was 1.8 s. The radial SWR technique is useful for demonstrating the hemodynamic features of vascular malformations in the head with 2D CE-MRDSA.     

Surveillance methodology for planning, and evaluation of nutritional states

In developing countries in general, malnutrition has been widely reported as a major public health problem. Most of morbidity and mortality in these countries especially in the under fives are attributed to nutritional deficiencies at least in part. However, documentation of malnutritional problems in these countries is inadequate for monitoring, planning and coordination of control programmes. The data that is collected in few instances where this is accomplished is insufficient for a meaningful analysis. This paper suggests some simple epidemiological techniques which could be routinely employed using the existing health personnel to monitor and document temporal trends and types of data required for useful understanding of the problem.     

Implantable cardioverter defibrillator storm: nursing care issues for patients and families

Implantable cardioverter defibrillators (ICDs) are being used for primary and secondary prevention of life-threatening cardiac arrhythmias, and evidence suggests that increased use is likely in the future. ICD storm, the delivery of two or more shocks within 24 hours, occurs in 10% to 20% of patients who have ICDs and can have long-lasting psychological and physical consequences. An understanding of the factors associated with ICD storm, relevant assessment, and patient and family teaching and counseling can help clinicians to better meet the needs of patients who have experienced ICD storm.     

Warfarin-induced impairment of cortical bone material quality and compensatory adaptation of cortical bone structure to mechanical stimuli

Long-term warfarin use has been reported to increase fracture risk of rib and vertebra but not hip in elderly patients, but the mechanisms remain unknown. We hypothesized that warfarin would impair bone material quality but could not weaken bone strength under conditions with higher mechanical stimuli. To test this hypothesis, rats were randomized to vehicle or warfarin group at 4 weeks of age and subsequently weight matched into a sedentary or jumping exercise group at 12 weeks of age. At 6 months of age, osteocalcin content, bone mineral density (BMD), mineral size, material properties, morphological parameters, and biomechanical properties of cortical bones were evaluated. In order to seek evidence for a common mechanism of action, effects of nucleation rate of mineral crystals on their rigidity were also investigated using computer simulation. In humeral cortical bones, warfarin did not change BMD, but markedly decreased osteocalcin content, diminished mineral size, and impaired material hardness. Consistent with these results, our computer-simulation model showed that osteocalcin-induced delay of mineral crystal nucleation decreased mineral formation rate, increased mean and distribution of mineral sizes, and strengthened mineral rigidity. In tibial cortical bones, warfarin decreased material ultimate stress; however, under jumping exercise, warfarin increased cross-sectional total and bone areas of these tibiae and completely maintained their biomechanical properties including work to failure. Collectively, our findings suggest that long-term warfarin therapy weakens rib and vertebra by impairing cortical bone material quality due to a marked decrease in osteocalcin content but could not reduce hip strength through compensatory adaptation of cortical bone structure to higher mechanical stimuli.     

Development and assessment of an automatic quantitative cerebral vascular reserve estimation tool for use with triple-injection 99mTc-ECD SPECT

In nuclear medicine, cerebral vascular reserve(CVR) is evaluated using technetium-99m ethyl cysteinate dimer [99mTc-ECD] and acetazolamide(ACZ). We developed a protocol involving the intravenous injection of 99mTc-ECD in three divided doses(TIE method), and have found that the cerebrovascular response to ACZ depended on time after ACZ administration. However, it was difficult to obtain high-precision quantitative SPECT images by the conventional method because of complicated image processing and image degradation accompanying image subtraction. We recently developed software known as the Automatic Quantitative CVR Estimation Tool(hereinafter referred to as Triple AQCEL), which, after the input of simple parameters, enables us to carry out automatic reconstruction of quantitative SPECT images without image degradation due to subtraction. Triple AQCEL was determined to reduce image degradation caused by subtraction and to provide valid quantitative data. Because Triple AQCEL does not require manual determination of ROI or image selection for the reconstruction of quantitative SPECT images, reproducibility of regional cerebral blood flow by 3DSRT is ensured. Since all analyses in evaluation by the TIE method are automated and the operator plays no part in them, with the resulting increase of throughput, this software will contribute to improved reproducibility of regional cerebral blood flow data, and will be useful in clinical pathophysiological assessment both preoperatively and during postoperative follow-up.