Citations

We tested the hypothesis that elevated sympathetic tone is responsible for lower peak vasodilation after single muscle contractions in older adults. Young ( n = 13, 7 men and 6 women, age: 27 ± 1 yr) and older ( n = 13, 7 men and 6 women, age: 69 ± 2 yr) adults performed single forearm contractions at 10%, 20%, and 40% of maximum during 1) control, 2) sympathetic activation via lower body negative pressure (LBNP; −20 mmHg), and 3) intra-arterial infusion of phentolamine (α-adrenergic antagonist). Brachial artery diameter and velocities were measured via Doppler ultrasound, and forearm vascular conductance (FVC; in ml·min−1·100 mmHg−1) was calculated from blood flow (in ml/min) and blood pressure (in mmHg). Peak vasodilator responses [change in (Δ) FVC from baseline] were attenuated in older adults at 20% and 40% of maximum ( P < 0.05). LBNP reduced peak ΔFVC at 10% (98 ± 17 vs. 70 ± 12 ml·min−1·100 mmHg−1), 20% (144 ± 12 vs. 98 ± 3 ml·min−1·100 mmHg−1), and 40% (209 ± 20 vs. 161 ± 21 ml·min−1·100 mmHg−1, P < 0.01 vs. control) in younger adults but not in older adults (71 ± 11 vs. 68 ± 11, 107 ± 13 vs. 106 ± 16, and 161 ± 22 vs. 144 ± 22 ml·min−1·100 mmHg−1, respectively, P = 0.22–0.99). With phentolamine, peak ΔFVC was enhanced in older adults at each contraction intensity (100 ± 14, 147 ± 22, and 200 ± 26 ml·min−1·100 mmHg−1, respectively, P < 0.01 vs. control) but not in younger adults (94 ± 13, 153 ± 13, and 224 ± 27 ml·min−1·100 mmHg−1, respectively, P = 0.30–0.81 vs. control). Our data indicate that α-adrenergic vasoconstriction and/or blunted functional sympatholysis might contribute to the age-related decreases in skeletal muscle contraction-induced rapid vasodilation in humans.

OBJECTIVE To investigate the pharmacokinetics (PK), pharmacodynamics, and safety of single-dose RM-131 in type 2 diabetic patients with gastrointestinal cardinal symptoms (GCSI) and previously documented delayed gastric emptying (DGE). RESEARCH DESIGN AND METHODS In a randomized crossover study, 10 female patients received RM-131 (100 μg s.c.) or placebo and underwent scintigraphic gastric emptying (GE) and colonic filling at 6 h (CF6) of a solid-liquid meal administered 30 min postdosing. Adverse events, plasma glucose, and hormonal levels were assessed. GCSI daily diary (GCSI-DD) was completed during treatments. PK was assessed in this cohort and healthy volunteers (HVs). RESULTS At screening, HbA1c was 7.2 ± 0.4% (SEM) and total GCSI-DD score was 1.32 ± 0.21. RM-131 accelerated GE t1/2 of solids (P = 0.011); mean difference (Δ) in solid GE t1/2 was 68.3 min (95% CI 20–117) or 66.1%. There were numerical differences in GE lag time, CF6 solids, and GE t1/2 liquids (all P &lt; 0.14). With a significant (P &lt; 0.014) order effect, further analysis of the first treatment period (n = 5 per group) confirmed significant RM-131 effects on GE t1/2 (solids, P = 0.016; liquids, P = 0.024; CF6, P = 0.013). PK was similar in DGE patients and HVs. There were increases in 120-min blood glucose (P = 0.07) as well as 30–90-min area under the curve (AUC) levels of growth hormone, cortisol, and prolactin (all P &lt; 0.02) with single-dose RM-131. Only light-headedness was reported more on RM-131. CONCLUSIONS RM-131 greatly accelerates the GE of solids in patients with type 2 diabetes and documented DGE. PK is similar in diabetic patients and HVs.

Object Gangliogliomas comprise less than 1% of all brain tumors and occur most often in children. Therefore, there are a limited number of patients and data involving the use or role of adjuvant therapy after subtotal resections (STRs) of gangliogliomas. The objective of this study was to examine and review the Mayo Clinic experience of 88 patients with gangliogliomas, their follow-up, risk of recurrence, and the role of radiation therapy after STR or only biopsy. Methods Eighty-eight patients with gangliogliomas diagnosed between 1970 and 2007 were reviewed. Data on clinical outcomes and therapy received were analyzed. The Kaplan-Meier method was used to estimate progression-free survival (PFS) and overall survival. Results The median age at diagnosis was 19 years. The median potential follow-up as of June 2008 was 142 months (range 9–416 months). Fifteen-year overall survival was 94%, median PFS was 5.6 years, with a 10-year PFS rate of 37%. Progression-free survival was dramatically affected by extent of initial resection (p < 0.0001). Conclusions This single-institution retrospective series of patients with gangliogliomas is unique given its large cohort size with a long follow-up duration, and confirms the excellent long-term survival rate in this group. The study also shows the importance of resection extent on likelihood of recurrence. Patients with gangliogliomas who undergo STR or biopsy alone have poor PFS. Radiation therapy may delay time to progression in patients with unresectable disease.

AbstractTo address the pending public health crisis due to Alzheimer's disease (AD) and related neurodegenerative disorders, the Marian S. Ware Alzheimer Program at the University of Pennsylvania held a meeting entitled “State of the Science Conference on the Advancement of Alzheimer's Diagnosis, Treatment and Care,” on June 21‐22, 2012. The meeting comprised four workgroups focusing on Biomarkers; Clinical Care and Health Services Research; Drug Development; and Health Economics, Policy, and Ethics. The workgroups shared, discussed, and compiled an integrated set of priorities, recommendations, and action plans, which are presented in this article.

Postganglionic sympathetic neurons in the prevertebral ganglia (PVG) provide ongoing inhibitory tone to the gastrointestinal tract and receive innervation from mechanosensory intestinofugal afferent neurons primarily located in the colon and rectum. This study tests the hypothesis that colitis alters the excitability of PVG neurons. Intracellular recording techniques were used to evaluate changes in the electrical properties of inferior mesenteric ganglion (IMG) neurons in the trinitrobenzene sulfonic acid (TNBS) and acetic acid models of guinea pig colitis. Visceromotor IMG neurons were hyperexcitable 12 and 24 h, but not 6 h, post-TNBS during “acute” inflammation. Hyperexcitability persisted at 6 days post-TNBS during “chronic” inflammation, as well as at 56 days post-TNBS when colitis had resolved. In contrast, there was only a modest decrease in the current required to elicit an action potential at 24 h after acetic acid administration. Vasomotor neurons from inflamed preparations exhibited normal excitability. The excitatory effects of XE-991, a blocker of the channel that contributes to the M-type potassium current, and heteropodatoxin-2, a blocker of the channel that contributes to the A-type potassium current, were unchanged in TNBS-inflamed preparations, suggesting that these currents did not contribute to hyperexcitability. Riluzole, an inhibitor of persistent sodium currents, caused tonic visceromotor neurons to accommodate to sustained current pulses, regardless of the inflammatory state of the preparation, and restored a normal rheobase in neurons from TNBS-inflamed preparations but did not alter the rheobase of control preparations, suggesting that enhanced activity of voltage-gated sodium channels may contribute to colitis-induced hyperexcitability. Collectively, these data indicate that enhanced sympathetic drive as a result of hyperexcitable visceromotor neurons may contribute to small bowel dysfunction during colitis.

A Fine Balance Intellectual and neurological disabilities can arise from diverse developmental aberrations. Novarino et al. (p. 394 , published online 6 September; see the Perspective by Beaudet ) have now determined the genetic basis for one such disorder for a small group of patients. Exome sequencing led to identification of mutations in a kinase BCKDK ( Branched Chain Ketoacid Dehydrogenase Kinase ) that regulates metabolism of branched-chain amino acids such as valine, leucine, and isoleucine. Mice with homozygous mutations in the BCKDK gene showed developmental and neurological abnormalities resembling those in certain mouse autism models. Analysis of transport mechanisms responsible for carrying amino acids across the blood-brain barrier revealed competition between the branched-chain amino acids and large neutral amino acids. Nutritional supplementation with extra branched-chain amino acids in the diet of mice carrying homozygous mutations in the BCKDK gene normalized their phenotype.