Bone Density Following Three Years of Recovery from Long-Duration Space Flight

It is well recognized that bone mineral density [BMD] at load-bearing sites of the hip and spine sustain significant loss during space flight, estimated at approximately 0.5-1.0% per month. However, the long-term effects on bone health following return from long-duration space flight remain unclear. It is unknown whether BMD for men recovers beyond 1 year following return from space to what would be predicted or if deficits persist. Using our previously created prediction models, we compared the observed BMD of male US crew following 3 years since returning from longduration space flight with what would be predicted if they had not been exposed to microgravity

Does Short Duration Space Flight have a Negative Effect on Bone Density?

No abstract availabl

What Accounts for Rib Fractures in Older Adults?

To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21–93 years was followed in a long-term prospective study. Bone mineral density (BMD) was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years), 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes

Bone Density Following Long Duration Space Flight and Recovery

At approx.12 months, Bone Mineral Density (BMD) at most sites in men remained lower than would be predicted, raising concerns for long-term bone health consequences following space flight. Additional analyses based on longer follow-up are being conducted. Although the N is too small for definitive conclusions, women had lower rates of loss at load-bearing sites of the hip and spine immediately post-flight relative to men and smaller differences between observed vs. predicted BMD at most sites, both immediately and 12 months post-flight, relative to men. The role of other exposures/risk factors need to be explored to further understand these possible gender differences in BMD loss and recovery following long-duration space flight

Molecular Characterization of the Non-biotin-containing Subunit of 3-Methylcrotonyl-CoA Carboxylase

The biotin enzyme, 3-methylcrotonyl-CoA carboxylase (MCCase) (3-methylcrotonyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.4), catalyzes a pivotal reaction required for both leucine catabolism and isoprenoid metabolism. MCCase is a heteromeric enzyme composed of biotin-containing (MCC-A) and non-biotin-containing (MCC-B) subunits. Although the sequence of the MCC-A subunit was previously determined, the primary structure of the MCC-B subunit is unknown. Based upon sequences of biotin enzymes that use substrates structurally related to 3-methylcrotonyl-CoA, we isolated the MCC-B cDNA and gene ofArabidopsis. Antibodies directed against the bacterially produced recombinant protein encoded by the MCC-B cDNA react solely with the MCC-B subunit of the purified MCCase and inhibit MCCase activity. The primary structure of the MCC-B subunit shows the highest similarity to carboxyltransferase domains of biotin enzymes that use methyl-branched thiol esters as substrate or products. The single copy MCC-B gene of Arabidopsis is interrupted by nine introns. MCC-A and MCC-BmRNAs accumulate in all cell types and organs, with the highest accumulation occurring in rapidly growing and metabolically active tissues. In addition, these two mRNAs accumulate coordinately in an approximately equal molar ratio, and they each account for between 0.01 and 0.1 mol % of cellular mRNA. The sequence of theArabidopsis MCC-B gene has enabled the identification of animal paralogous MCC-B cDNAs and genes, which may have an impact on the molecular understanding of the lethal inherited metabolic disorder methylcrotonylglyciuria

Assessment of coronary artery disease and calcified coronary plaque burden by computed tomography in patients with and without diabetes mellitus

Purpose: To compare the coronary atherosclerotic burden in patients with and without type-2 diabetes using CT Coronary Angiography (CTCA). Methods and Materials: 147 diabetic (mean age: 65 ± 10 years; male: 89) and 979 nondiabetic patients (mean age: 61 ± 13 years; male: 567) without a history of coronary artery disease (CAD) underwent CTCA. The per-patient number of diseased coronary segments was determined and each diseased segment was classified as showing obstructive lesion (luminal narrowing >50%) or not. Coronary calcium scoring (CCS) was assessed too. Results: Diabetics showed a higher number of diseased segments (4.1 ± 4.2 vs. 2.1 ± 3.0; p 400 (p < 0.001), obstructive CAD (37% vs. 18% of patients; p < 0.0001), and fewer normal coronary arteries (20% vs. 42%; p < 0.0001), as compared to nondiabetics. The percentage of patients with obstructive CAD paralleled increasing CCS in both groups. Diabetics with CCS ≤ 10 had a higher prevalence of coronary plaque (39.6% vs. 24.5%, p = 0.003) and obstructive CAD (12.5% vs. 3.8%, p = 0.01). Among patients with CCS ≤ 10 all diabetics with obstructive CAD had a zero CCS and one patient was asymptomatic. Conclusions: Diabetes was associated with higher coronary plaque burden. The present study demonstrates that the absence of coronary calcification does not exclude obstructive CAD especially in diabetics

Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR

Objectives To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters. Methods Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced- steady state free precession) SAX sequence for MR, and evaluated using dedicated software. Results CT and MR images showed good agreement: LV EF (Ejection Fraction) (52±14% for CT vs. 52±14% for MR; r0 0.73; p>0.05); RV EF (47±12% for CT vs. 47±12% for MR; r00.74; p>0.05); LV EDV (End Diastolic Volume) (74± 21 ml/m 2 for CT vs. 76±25 ml/m 2 for MR; r00.59; p>0.05); RV EDV (84±25 ml/m 2 for CT vs. 80±23 ml/m 2 for MR; r0 0.58; p>0.05); LV ESV (End Systolic Volume)(37±19 ml/m 2 for CT vs. 38±23 ml/m 2 for MR; r00.76; p>0.05); RV ESV (46±21 ml/m 2 for CT vs. 43±18 ml/m 2 for MR; r00.70; p>0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups. Conclusions Cardiac CT provides accurate and reproducible LVand RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR. Key Points • Cardiac-CT is able to provide Left and Right Ventricular function. • Cardiac-CT is accurate as MR for LV and RV volume assessment. • Cardiac-CT can provide accurate evaluation of coronary arteries and LV and RV function