Change in Lumbar Muscle Size and Composition on MRI with Long-Duration Spaceflight

Annals of Biomedical Engineering - Prolonged microgravity results in muscle atrophy, especially among the anti-gravity spinal muscles. How individual paravertebral muscle groups change in size and...     

Histopathological heterogeneity of neuropathy in insulin-dependent and non-insulin-dependent diabetes, and demonstration of axo-glial dysjunction in human diabetic neuropathy.

Altered sorbitol and myo-inositol metabolism, (Na,K)-ATPase function, electrochemical sodium gradients, axonal swelling, and distortion and disruption of the node of Ranvier ("axo-glial dysjunction") directly implicate hyperglycemia in the pathogenesis of neuropathy in diabetic rats, but the relevance of this sequence to clinical neuropathy in heterogeneous groups of diabetic patients remains to be established. Fascicular sural nerve morphometry in 11 patients with neuropathy complicating insulin-dependent diabetes revealed a pattern of interrelated structural changes strikingly similar to that of the diabetic rat when compared to age-matched controls. 17 older non-insulin-dependent diabetic patients with comparable duration and severity of hyperglycemia and severity of neuropathy, displayed similar nerve fiber loss, paranodal demyelination, paranodal remyelination and segmental demyelination compared to age-matched controls, but axo-glial dysjunction was replaced by Wallerian degeneration as the primary manifestation of fiber damage, and fiber loss occurred in a spatial pattern consistent with an ischemic component. The mechanistic model developed from the diabetic rat does indeed appear to apply to human diabetic neuropathy, but superimposed hormonal, metabolic, vascular, and/or age-related effects alter the morphologic expression of the neuropathy in non-insulin dependent diabetes.     

Trends in Lumpectomy and Oncoplastic Breast-Conserving Surgery in the US, 2011–2016

Background

Oncoplastic breast surgery aims to optimize efficacy of surgical resection and cosmesis to maximize patient satisfaction; however, despite the benefits, oncoplastic techniques have not been widely adopted in the US. This study examined trends in the incidence of lumpectomy (partial mastectomy) with or without oncoplastic techniques from 2011 to 2016.

Methods

This was a retrospective analysis of claims from the Optum Clinformatics database (January 2010–March 2017). Female patients with no history of breast surgery in the prior year were categorized into three independent cohorts: isolated lumpectomy (Lx), lumpectomy with tissue transfer (LxTT), or lumpectomy with mammaplasty and/or mastopexy (LxMM). Oncoplastic techniques (in cohorts two and three) were performed at either time of the initial lumpectomy or during 90-day follow-up.

Results

Overall, 19,253 patients met the inclusion criteria (91.1% Lx, 5.2% LxTT, and 3.7% LxMM). Significantly fewer patients with Lx had a family history of breast cancer compared with patients with oncoplastic techniques (26.4% vs. 33.7% and 37.9%, respectively; p?<?0.001). The incidence of Lx declined significantly from 2011 (92.9%) to 2016 (88.1%), while LxTT and LxMM increased from 4.2 to 7.2% and 2.8 to 4.7%, respectively (both p?<?0.001). The greatest utilization of oncoplastic techniques was observed in the Pacific census division (19.2%), while lowest utilization was in the East South Central division (3.2%; p?<?0.001).

Conclusions

While increased adoption of oncoplastic techniques was observed, the compound annual growth rate remained below 10% and varied significantly by region. Further adoption of oncoplastic techniques is necessary to improve cosmetic outcomes and patient satisfaction following breast-conserving surgery.

     

Glycemic index and dietary fiber and the risk of type 2 diabetes

OBJECTIVE: To examine associations between type 2 diabetes and fiber, glycemic load (GL), dietary glycemic index (GI), and fiber-rich foods. RESEARCH DESIGN AND METHODS: This was a prospective study of 36,787 men and women aged 40-69 years without diabetes. For all self-reported cases of diabetes at 4-year follow-up, confirmation of diagnosis was sought from medical practitioners. Case subjects were those who reported diabetes at follow-up and for whom there was no evidence that they did not have type 2 diabetes. Data were analyzed with logistic regression, adjusting for country of birth, physical activity, family history of diabetes, alcohol and energy intake, education, 5-year weight change, sex, and age. RESULTS: Follow-up was completed by 31,641 (86%) participants, and 365 cases were identified. The odds ratio (OR) for the highest quartile of white bread intake compared with the lowest was 1.37 (95% CI 1.04-1.81; P for trend = 0.001). Intakes of carbohydrate (OR per 200 g/day 0.58, 0.36-0.95), sugars (OR per 100 g/day 0.61, 0.47-0.79), and magnesium (OR per 500 mg/day 0.62, 0.43-0.90) were inversely associated with incidence of diabetes, whereas intake of starch (OR per 100 g/day 1.47, 1.06-2.05) and dietary GI (OR per 10 units 1.32, 1.05-1.66) were positively associated with diabetes. These relationships were attenuated after adjustment for BMI and waist-to-hip ratio. CONCLUSIONS: Reducing dietary GI while maintaining a high carbohydrate intake may reduce the risk of type 2 diabetes. One way to achieve this would be to substitute white bread with low-GI breads.     

Reductions in coronary flow under resting conditions in collateral-dependent myocardium of patients with complete occlusion of the left anterior descending coronary artery

Flow per unit weight in collateral-dependent myocardium was quantified selectively in seven patients with complete occlusion of the proximal left anterior descending artery and prominent distal collateralization from the right coronary artery by infusing dissolved hydrogen into the right coronary artery for 10 to 15 minutes and monitoring hydrogen desaturation in the great cardiac vein. Coronary flow per unit weight in all myocardium draining into the great cardiac vein was quantified simultaneously by having the patient breathe helium and by monitoring arterial and great cardiac vein helium desaturation. Flow per unit weight in collateral-dependent myocardium averaged 38 +/- 8 (standard deviation) ml/min per 100 g and was in each case below the 95% confidence limit for normal individuals with the same rate-pressure product. Flow per unit weight in all myocardium draining into the great cardiac vein was systematically higher (51 +/- 8 ml/min per 100 g); because arteries other than the anterior descending had no stenoses greater than 30% in diameter, these values presumably reflect mixtures of subnormally perfused collateralized myocardium and adjacent normally perfused tissue. The findings suggest that coronary flow per unit weight is not maintained at usual basal values in densely collaterlized myocardium that is entirely collateral-dependent. The reductions in flow are presumably associated with marked reductions in local arterial pressure and raise the possibility of a chronic reduction in local myocardial metabolic demand.     

Impaired fasting glucose, diabetes mellitus, and cardiovascular disease risk factors are associated with prolonged QTc duration. Results from the Third National Health and Nutrition Examination Survey

BACKGROUND: Impaired glucose tolerance and diabetes mellitus have been associated with a prolonged QT interval among select populations. However, these associations remain unclear among the general population. METHODS: We examined these relationships using data from 5833 adults aged 40-90 years from NHANES III (1988-1994). Univariate differences in cardiovascular disease (CVD) risk factors were examined across tertiles of heart rate corrected QT (QTc). The association between glucose intolerance, CVD risk factors and a prolonged QTc (> or = 0.440 s) was also assessed with logistic regression adjusting for age, race, gender, education, and heart rate. RESULTS: Prolonged QTc was observed among 22.0% of persons with normal glucose tolerance (NGT), 29.9% of those with impaired fasting glucose (IFG), and among 42.2% of persons with diabetes. Hypertension, serum cholesterol, obesity, heart rate, and fasting C-peptide and serum insulin levels were associated with prolonged QTc (all: P < or = 0.05). After multivariate adjustment, persons with IFG were 1.2 times (95% CI=0.7-2.0) as likely and persons with diabetes 1.6 times (95% CI=1.1-2.3) as likely to have a prolonged QTc as persons with NGT. In addition, persons with diabetes and two or more additional CVD risk factors were 2.3 times (95% CI=1.3-4.0) as likely to have a prolonged QTc as persons with NGT and no CVD risk factors after multivariate adjustment. CONCLUSION: Diabetes was associated with an increased likelihood of prolonged QTc independent of age, race, gender, education, and heart rate. In addition, persons with diabetes and multiple CVD risk factors were more likely to have a prolonged QTc than those with NGT and no additional risk factors, suggesting that these persons may be at increased risk for cardiac arrhythmia and sudden death.     

Application of physiological genomics to the microcirculation

Physiological genomics represents a new challenge in the biological sciences-the quest to define the functions of thousands of genes that will emerge from the sequencing of the human genome and the genomes of other model organisms. Because the attention of the scientific community has focused on this task, new tools that will allow high-efficiency identification of gene function are being developed at remarkable speed. Physiological genomic approaches to understanding integrated systems function are now becoming widely used in many areas of biological research. The availability of genomic information across species has now revealed a striking degree of conservation of both gene order and function, allowing researchers to easily move from model organisms to man in the hunt for gene function. Physiological genomics approaches in the cardiovascular system have focused on disease-based models and the behavior of large vessels. In the microcirculation, genomic studies have largely been confined to the use of single gene knockouts or to the study of angiogenesis. This review summarizes the strategies for physiological genomics that are appropriate to the study of the microcirculation and discusses several key discoveries that have been made by using these approaches.