Previous studies have demonstrated that increased muscle lipid content is associated with reduced muscle strength and physical performance, independent of muscle mass. An association between elevated muscle lipid content with skeletal muscle attenuation has been reported in a large number of studies. The relationship between vitamin D serum levels and muscle strength is well established. Patients with vitamin D deficiency have increased body fat and decreased muscle strength. A similar association between vitamin D levels and muscle strength has been reported both in the elderly and in healthy adolescent postmenarcheal girls. In several studies, skeletal muscle attenuation was demonstrated in vitamin D deficient patients with neuromuscular disorders. It is unclear whether vitamin D insufficiency is also related to adipose tissue infiltration in muscle. In the present study, the investigators hypothesized that there was an inverse relationship between serum vitamin D levels and adipose tissue infiltration in muscle, which is independent of muscle mass. This cross-sectional study tested this hypothesis by examining the relationship between serum 25-hydroxyvitamin D (25OHD) and skeletal muscle lipid content and muscle mass in a cohort of healthy young women. The study subjects were 90 postpubertal females, aged 16 to 22 years. Study outcome measures included anthropometric characteristics, serum 25OHD values determined with radioimmunoassay, and values of fat, muscle mass, and percent muscle fat determined using computed tomography (CT). The participants were divided into 2 groups based on baseline vitamin D levels: 41% (n = 37) were 25OHD sufficient (≥30 ng/mL) and 59% (n = 53) were 25OHD insufficient (≤29 ng/mL); 24% of the latter were 25OHD deficient (≤20 ng/mL). The data demonstrated a strong inverse relationship between serum 25OHD levels and CT measurements of percent muscle fat (r = −0.37; P < 0.0003), whereas no such relationship was found between the 2 vitamin D groups for fat infiltration in the thigh muscle area (r = 0.16; P = 0.14). Multiple regression analysis showed that the association between 25OHD levels and percent muscle fat was independent of body mass or CT measures of subcutaneous and visceral fat. Compared with the vitamin D sufficient group, percent muscle fat was significantly higher in the vitamin D insufficient group (3.15 ± 1.4 vs. 3.90 ± 1.9; P = 0.038). These findings indicate that vitamin D insufficiency has an inverse association with fat infiltration in muscle, which is independent of body mass.
It has generally been believed that adiposity contributes to bone health and protects against osteoporosis. A number of studies have shown a positive association between body weight or body mass index and bone mass. In recent years, however, this long-held viewpoint has been challenged by reports suggesting that there is no positive association of fat mass and/or that there may be a negative relationship. There is accumulating evidence that the regional distribution pattern of fat deposition into the subcutaneous and visceral abdominal compartments may explain these conflicting data. Measurements of fat deposition into these 2 compartments may be a more meaningful predictor of disease risk than overall fat mass. The possible independent effects of subcutaneous abdominal fat (SAF) and visceral abdominal fat (VAF) on bone health have not been previously investigated. This study investigated the effect of differential deposition of SAF and VAF on bone structure and/or bone strength in the appendicular skeleton of 100 healthy young females 15 to 25 years of age, computed tomography was used for measurements of fat, bone, and muscle phenotypes. Calculations of cross-sectional area, cortical bone area, maximum and minimum principal moments of inertia, and polar moment of inertia, were made using multiple linear regression analysis. After adjusting for leg length and thigh musculature, the data showed that both SAF and VAF had strong and independent associations with femoral cross-sectional area, cortical bone area, maximum and minimum principal moments of inertia, and polar moment of inertia (P < 0.03 for all comparisons). Although a positive predictive value was found for SAF with all femoral bone phenotypes, there was a similar but negative effect between VAF and these measures (P < 0.01 for all comparisons). These findings indicate that SAF and VAF have opposing effects on the structure and strength of bone in young women. SAF has a strong beneficial effect on parameters of bone structure and strength, whereas VAF has a negative association with all bone phenotypes.
Alzheimer’s disease, a progressive and irreversible brain disorder predominantly affecting the elderly, is influenced by age, smoking, and head trauma. It disrupts memory, cognition, motor skills, speech, and more. Alzheimer’s disease pathophysiology is caused by two main processes: the formation of misfolded amyloid-beta plaques and misfolded tau tangles. While tau is a naturally occurring, microtubule-associated protein, amyloid-beta peptides are cleaved fragments of the transmembrane amyloid precursor protein. Accumulation of these plaques and tangles result in various negative mechanisms. Regarding the relationship between the two proteins, evidence suggests that amyloid beta induces the conversion of tau from a normal to toxic state, but they ultimately work together to contribute to Alzheimer’s disease pathogenesis. As of currently, there is still no cure for the disease, and patients rely on treatment methods that solely alleviate symptoms or benefit early stages to halt the disease’s progression. The main medications for Alzheimer’s disease are cholinesterase inhibitors such as Donepezil and Galantamine, but novel pharmacological and non-pharmacological treatments are being utilized as well, such as β-secretase inhibitors and deep brain stimulation respectively. This review investigates peer-reviewed publications on pathophysiology and treatment of Alzheimer’s disease, with a focus on novel approaches for treatment and intervention.
Vitamin D insufficiency has now reached epidemic proportions and has been linked to increased body fat and decreased muscle strength. Whether vitamin D insufficiency is also related to adipose tissue infiltration in muscle is not known.The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD) and the degree of fat infiltration in muscle.This was a cross-sectional study. OUTCOME MEASURES AND SUBJECTS: Measures were anthropometric measures, serum 25OHD radioimmunoassay values, and computed tomography (CT) values of fat, muscle mass, and percent muscle fat in 90 postpubertal females, aged 16-22 yr, residing in California.Approximately 59% of subjects were 25OHD insufficient (< or = 29 ng/ml), of which 24% were deficient (< or = 20 ng/ml), whereas 41% were sufficient (> or = 30 ng/ml). A strong negative relationship was present between serum 25OHD and CT measures of percent muscle fat (r = -0.37; P < 0.001). In contrast, no relationship was observed between circulating 25OHD concentrations and CT measures of thigh muscle area (r = 0.16; P = 0.14). Multiple regression analysis indicated that the relation between 25OHD and muscle adiposity was independent of body mass or CT measures of sc and visceral fat. Percent muscle fat was significantly lower in women with normal serum 25OHD concentrations than in women with insufficient levels and deficient levels (3.15 +/- 1.4 vs. 3.90 +/- 1.9; P = 0.038).We found that vitamin D insufficiency is associated with increased fat infiltration in muscle in healthy young women.
Increased body fat is a risk factor for cardiovascular and metabolic disease, yet it is uncertain whether obesity protects against osteoporosis or adiposity is harmful to bone.The aim of the study was to assess whether the pattern of adipose tissue deposition influences bone structure and strength.The relations between sc and visceral adiposity and the cross-sectional dimensions and polar and principal moments of the femur in 100 healthy women ages 15 to 25 years were obtained using computed tomography.Multiple linear regression analyses indicated that, after adjusting for leg length and thigh musculature, both sc and visceral fat had strong and independent associations with femoral cross-sectional area, cortical bone area, principal moment maximum, principal moment minimum, and polar moment (all P values < 0.03). However, whereas sc fat had a positive predictive value with all femoral bone phenotypes, a similar but negative effect was observed between visceral fat and these measures (all P values < 0.01).We found that visceral and sc fat have opposite effects on the appendicular skeleton; whereas sc fat is beneficial to bone structure and strength, visceral fat serves as an unique pathogenic fat depot.
In low-resource areas, pulmonary diseases are often misdiagnosed or underdiagnosed due to a lack of trained clinical staff and diagnostic lab equipment (e.g. spirometry, DLCO). In these settings, traditional methods of pulmonary disease screening often include a lengthy questionnaire (>30 questions) and stethoscope auscultation. Unfortunately, such tools are not appropriate for general practitioner (GP) doctors or community health workers who have little time or experience diagnosing pulmonary disease. We propose a computer-based deep learning algorithm that could enable rapid screening of the most common pulmonary diseases (COPD, Asthma, and respiratory infection (COVID-19)) using voluntary cough sounds alone. Using a dataset of 348 cough recordings, raw cough recordings were segmented into individual coughs and converted to Mel Spectrogram images. We trained two types of models for comparison, binary and multi-class, using transfer learning with VGG19. The resulting Receiver Operating Characteristic (ROC) curves and the Area Under Curve (AUC) accuracy for each model was calculated to evaluate performance. Binary AUC accuracies were 0.73, 0.70, 0.87, and 0.70 for healthy, asthma, COPD, and COVID-19 respectively, while multi-class AUC accuracies were 0.78, 0.67, 0.95, 0.70. This demonstrates good potential for creating a simple low-cost screening tool that is fast to administer. Future versions of the model will use ongoing data collection to expand to more diseases including tuberculosis and pneumonia.
Despite advances in stroke care, readmission rates for patients with ischemic stroke remain high. Although factors such as age, diabetes, and continuous use of antiplatelet agents have been found to predict readmission rates, the impact of after-hospital care has not been examined.The present study reviewed the charts of 416 patients with acute ischemic stroke and recorded stroke-related comorbidities, neurology follow-up within 21 days, readmission at 0 to 30 days, readmission at 31 to 90 days, and any reasons for readmission.For those readmitted within 0 to 30 days, reasons for readmission were other medical conditions (62.5%), recurrent stroke (30.4%), and elective procedure (7.1%). For those readmitted within 31 to 90 days, reasons for readmission were other medical conditions (62.3%), recurrent stroke (15.1%), and elective procedure (22.6%). There was no significant relationship between being evaluated within 21 days and readmission at 0 to 30 or 31 to 90 days. However, those who did have a neurology follow-up at any point in time had a lower readmission rate of 10.6% compared to those who never came back (19.2%, P = .017). Patients with coronary artery disease and diabetes had a significantly higher likelihood of readmission within 0 to 30 days.The present study suggests that neurology follow-up at any point in time for patients with acute ischemic stroke may reduce short-term readmissions, but special attention to optimizing management of other underlying medical conditions, coronary artery disease, or diabetes may also help reduce overall readmissions. Patients with stroke, therefore, may benefit from a follow-up with both the primary care and neurology in a coordinated fashion to prevent early readmissions at 30 days.
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