Heart rate variability after bariatric surgery: The add-on value of exercise.

PURPOSE: To assess the impact of bariatric surgery and an added supervised exercise training programme on heart rate variability (HRV) in patients with severe obesity. METHODS: Fifty-nine patients who underwent bariatric surgery were randomised in the post-operative period to a 12-week supervised exercise training programme (moderate intensity combination aerobic/resistance exercise training programme) or a control group. Indices of HRV including time-domain, spectral-domain, and nonlinear parameters were measured preoperatively, and at 3, 6, and 12 months. RESULTS: After the surgical procedure, both groups improved anthropometric parameters. Type 2 diabetes, hypertension, and dyslipidemia resolutions were similar between groups. Total body weight loss at 6 and 12 months were also comparable between groups (6 months: 28 ± 6 vs. 30 ± 6%; 12 months: 38 ± 9 vs. 38 ± 10%; control vs. intervention group respectively). Bariatric surgery improved HRV parameters at 12 months compared to the pre-operative values in the intervention group: standard deviation of R-R interval (SDNN) (156.0 ± 46.4 vs. 122.6 ± 33.1 ms), low frequency (LF) (6.3 ± 0.8 vs. 5.8 ± 0.7 ms2), and high frequency (HF) (5.1 ± 0.8 vs. 4.7 ± 0.9 ms2) (all p<0.001). For the control patients, similar improvements in SDNN (150.0 ± 39.4 vs. 118.8 ± 20.1 ms), LF (6.1 ± 0.9 vs. 5.7 ± 0.8 ms2), and HF (5.0 ± 0.9 vs. 4.7 ± 0.9 ms2) were obtained (all p<0.001). However, there was no add-on impact of the supervised exercise training programme on HRV after 12 months (p>0.05 for all HRV parameters). CONCLUSION: Bariatric surgery is associated with an improvement in HRV. A supervised exercise training programme in the post-operative period did not modulate further the benefits of bariatric surgery regarding HRV parameters.

A strategy for a convergent synthesis of N-linked glycopeptides on a solid support.

Oligosaccharides and glycopeptides are of considerable importance in molecular biology and pharmacology. However, their synthesis is complicated by the large number of different linking sites between each saccharide unit, the need for stereochemical control, the chemical sensitivity of the glycopeptide bonds, and the need to harmonize diverse protecting groups. Here, an efficient solid-phase synthesis of three N-linked glycopeptides based on glycal assembly is presented. The peptide domain can be extended while the ensemble remains bound to the polymer. The glycopeptides synthesized here are among the largest N-linked glycopeptides ever accessed by either solution- or solid-phase synthesis.

Chemisorption-repulsion energies of H2 on surface (110) of Mg1-xMx alloys (M = Al, Ni, Zn; 0.0 ≤ x ≤ 0.20) as a function of temperature.

In recent years, the popularity of metal hydrides has increased considerably for hydrogen storage and their applications in hydrogen fuel cells. Their potential applications for clean energy are promissory. However, the temperatures required for adsorption and desorption are extremely high, which range between 500 and 700 K, making their use impractical. To overcome these difficulties, the following work considers using three hydride alloys: magnesium-aluminum (MgAl), magnesium-nickel (MgNi), and magnesium-zinc (MgZn). The Mg concentrations were set to be between 80 and 100 wt% in order to reduce the temperatures of adsorption and desorption in contrast with the temperatures of pure magnesium. The chemisorption and repulsion energies of the hydrogen molecule on the surface (110) of the different metallic alloys were studied at 0, 200, 400, 600, and 700 K, respectively. The study was based on the density functional theory (DFT), with the module DMol3 of the molecular simulation program Materials Studio, which was used to obtain these energy values. The results confirm that adding aluminum, nickel, or zinc into magnesium matrix increases the chemisorption and decreases the energy repulsion values on surfaces of the metallic alloys, improving the effectiveness of the hydrogen storage.

Secretion of proglucagon-derived peptides in response to intestinal luminal nutrients.

To establish whether secretion of proglucagon-derived peptides (PGDPs) by the intestinal L cell is nutrient- and/or location-dependent, 0.9% saline, 200 mM glucose, or emulsified fats were administered into the ileal or duodenal lumen of normal rats. Fat administration, but not saline or glucose treatment, significantly increased circulating levels of the intestinal PGDPs in a time-dependent fashion, indicating a selectivity of the L cell in its response to nutrients. Interestingly, the response to duodenal fats was quantitatively and qualitatively identical to the response to ileal fats, despite 50-fold lower concentrations of PGDPs in the duodenum. These results suggest the existence of a duodenal factor that stimulates ileal PGDP secretion in response to fat ingestion. Ileal and plasma levels of gut PGDPs have been reported to be elevated in poorly controlled streptozotocin-diabetic rats. Whether the sensitivity of the L cell to luminal nutrients is altered in diabetes was, therefore, also examined. The L cell responses to luminal nutrients in diabetic rats were not significantly different from those of the normal rat, indicating a normal responsiveness of the L cell. However, independent of changes in glycemia, luminal glucose perfusion significantly decreased circulating glucagon levels in normal rats, but not in diabetics. Furthermore, luminal fat administration increased plasma glucagon levels in normal rats only. These results indicate that moderately controlled diabetes is associated with alterations in the pancreatic A cell, but not the intestinal L cell response to ingested nutrients. The results of the present study indicate that the response of the intestinal L cell to ingested food is nutrient-specific and that this specificity is not altered in diabetes. A duodenal-ileal axis is proposed to contribute to increments in circulating intestinal PGDPs in response to nutrient ingestion.

Regulation of intestinal proglucagon-derived peptide secretion by glucose-dependent insulinotropic peptide in a novel enteroendocrine loop.

Incretins are intestinal factors that stimulate postprandial insulin secretion in preparation for subsequent rises in plasma levels of ingested nutrients. Glucose-dependent insulinotropic peptide (GIP), a duodenal endocrine peptide, is ideally located for such a function. In contrast, the intestinal proglucagon-derived peptide (PGDP), truncated GLP-1 [GLP-1(7-37) or tGLP-1] is equipotent to GIP in insulinotropic activity, but due to its localization in the distal ileum, appears to be poorly situated to fulfill an incretin role in response to direct nutrient stimulation. Despite its distribution, rapid increments in plasma levels of tGLP-1 have been noted in response to nutrient ingestion. We have recently reported that GIP (but not other nutrient-stimulated duodenal endocrine peptides) can stimulate intestinal PGDP secretion in vitro, and therefore hypothesized that GIP might regulate secretion of the intestinal PGDPs, including tGLP-1, in response to nutrient ingestion in vivo in the rat. Placement of either fat or glucose directly into the ileal lumen was demonstrated to significantly stimulate secretion of the intestinal PGDPs (P < 0.05), whereas fat or glucose in the duodenal lumen significantly increased plasma levels of GIP (P < 0.05). In addition, however, duodenal fat treatment also increased the secretion of intestinal PGDPs into the circulation (P < 0.05), with levels rising to same extent as observed after direct administration of fat into the ileum. The rise in plasma GIP levels in response to duodenal fat treatment occurred slightly before the increments in intestinal PGDP levels, suggesting a relationship between the two peptides. Intravenous infusion of GIP to give concentrations similar to those observed after duodenal fat administration induced a 2-fold increase in plasma levels of intestinal PGDPs that was independent of glycemic levels (P < 0.05). No increment in intestinal PGDPs was found in response to infusion of another duodenal endocrine peptide, cholecystokinin. Thus, these data demonstrate a specific effect of GIP to stimulate secretion of the intestinal PGDPs in vivo in the rat. This enteroendocrine loop between the duodenal peptide GIP and the ileal PGDPs may account for some of the early rises in secretion of tGLP-1 observed in response to nutrient ingestion.

Gastrin-releasing peptide is a novel mediator of proximal nutrient-induced proglucagon-derived peptide secretion from the distal gut.

The ileal proglucagon-derived peptides (PGDPs) play important roles in the regulation of gastric function and insulin secretion. We have previously demonstrated the existence of a proximal-distal enteroendocrine loop mediated by glucose-dependent insulinotropic peptide (GIP), through which intestinal PGDP secretion is stimulated after placement of nutrients in the duodenum. To study the possible involvement of neuropeptides in this loop, we infused gastrin-releasing peptide (GRP) into anesthetized rats at 47, 235, or 470 ng/h. GRP stimulated secretion of the intestinal PGDPs only at the highest dose, from 250 +/- 18 to 321 +/- 9 pg/ml (P < 0.05). Gastrin secretion was also increased by GRP infusion (from 20 +/- 7 to 75 +/- 19 pg/ml; P < 0.05); however, GIP release was not altered from basal levels. Placement of fat into the duodenum stimulated the secretion of both the intestinal PGDPs and GIP (to 618 +/- 221 and 417 +/- 154 pg/ml above basal, respectively; P < 0.05). However, infusion of the GRP antagonist, BW10 (3 ng/h), completely abrogated the PGDP response to duodenal fat (P < 0.05). In contrast, the GIP response was reduced by 56 +/- 15% (P < 0.05) with BW10 administration, but remained elevated compared to the basal level (P < 0.05). Removal of the entire intestine distal to the fat-infused duodenal segment prevented the rise in intestinal PGDPs, but not that of GIP, demonstrating the distal and proximal origins of these peptides, respectively. Thus, placement of fat into the duodenum stimulated the release of the PGDPs from the distal intestine through a GRP-dependent mechanism. Although GIP plays a role in regulating intestinal PGDP secretion in the rat, GRP appears to exert its effects independent of changes in GIP.

Case study: dreamy state and temporal lobe dysfunction in a migrainous adolescent.

Symptoms of migraine can be very atypical during childhood and adolescence. This article describes a case in which the symptoms of migraine were mainly psychiatric: dreamy state, intermittent confusion, partial amnesia, and childlike regressive behavior with depressive features. Although the results from neurological examinations and electroencephalographic recordings were normal when the individual was symptomatic or not, temporal lobe dysfunction, determined by 99mTc-hexamethyl-propyleneamine oxamine single-photon emission computed tomography, was evident during the migraine.

Long-term results of low power, long duration laser trabeculoplasty.

We performed argon laser trabeculoplasty using 0.2-second duration on 15 patients with primary open-angle glaucoma. We then retrospectively compared the results to a similar group of 14 patients on whom a duration of 0.1 second was used. Power was titrated to achieve blanching or small bubble formation. All the other treatment variables were kept constant. Before treatment, the two groups did not differ in mean age, visual acuity, intraocular pressure, or number of drugs. After treatment, there was a 7 to 8 mm Hg decrease in intraocular pressure for both groups over a two-year follow-up period. No statistically significant difference between the two groups was observed for intraocular pressure, visual acuity, or drug score at the various follow-up periods. No patient required subsequent filtering surgery.

Proglucagon-derived peptides in the neuroendocrine system.

Using several novel in vitro culture systems, we have examined the tissue-specific regulation of the proglucagon-derived peptides, at the levels of proglucagon gene expression and pGdp synthesis and secretion. Our studies indicate that proglucagon gene expression in intenstine, hypothalamus and pancreas is under the regulatory control of protein kinase A- but not a protein kinase C-dependent pathway. PKA and PKC stimulate secretion of the intestinal pGdp's, whereas only PKA stimulates secretion of the hypothalamic peptides. Pancreatic glucagon secretion in response to PKA is subject to further modulation by prevailing glucose concentrations. This diversity in intracellular regulation of the pGdp's may account for some of the tissue-specific differences in synthesis and secretion of the pGdp's that we have observed in diabetes and during development.

Human abductor pollicis brevis muscle "divisions" and the nerve hila.

The interpretation of neuromuscular impairment may be aided by an analysis of functional anatomic factors. The anatomy of the abductor pollicis brevis (APB), a muscle used for skilled movements, was investigated in 19 embalmed hands, and the muscular divisions joining the common tendon at different sites were reproduced on clear vinyl sheets. The median nerve pathway to thenar muscles was followed to where it divides to the APB nerve and to the sites of the main terminal hila. Transverse (x) and longitudinal (y) muscle axes were established with the aid of landmarks to reproduce the nerve pathway on the skin surface. In the rather thick APB, three groups of six muscular heterogeneous divisions were regularly present. The dorsal aponeurotic expansion of the thumb receives the first group. The second group forms a continuous vertical line from the base to the body of the first phalanx. The outside site of its lateral tubercle takes the central tendon from the penniform third group. Hence, a reverse figure-seven distal insertion can be observed. The deepest medial (V2) and the most superficial lateral (V3) divisions had the highest mean diameters. The APB nerve fell between V2 and V2' and its line of projection supplied a guideline to establish an x axis at the proximal one-third of the muscle. The nerve hila plotted in relation to the x-y axes revealed a mode of location. The classical description of a thin APB muscle, made up of two bellies of parallel fibers seems incorrect. The APB nerve is not found on the deep aspect of the muscle as stated earlier, but within the muscle. The well-innervated muscular divisions point to the possibility of their individual use. The APB neuromuscular projection to the skin should allow more accurate fundamental EMG studies of the thumb and therefore provide a basis for more effective treatment in cases of impaired APB.

Effects of OspA vaccination on Lyme disease serologic testing.

This study presents the effects of OspA vaccination on two-step testing for Borrelia burgdorferi antibodies. Although vaccinees developed enzyme-linked immunosorbent assay reactivity, immunoblots did not fulfill Centers for Disease Control and Prevention criteria for positivity. Furthermore, OspA reactivity did not interfere with interpretation of immunoblots with sera from patients who developed early Lyme disease despite vaccination.