The effects of Calorie restriction and Bariatric surgery on Circulating Proneurotensin levels

CONTEXT

Proneurotensin (pNT) is associated with obesity and T2D, but the effects of Roux-en-Y gastric bypass (RYGB) on postprandial pNT levels are not well studied.

OBJECTIVE

Assess effects of RYGB versus very low-energy diet (VLED) on pNT levels in response to mixed-meal tests (MMT), and long-term effects of RYGB on fasting pNT.Study participants: Cohort 1: Nine normoglycemic (NG) and ten T2D patients underwent MMT before and after VLED, immediately post-RYGB and six weeks post-RYGB. Cohort 2: Ten controls with normal weight and ten patients with obesity and T2D, who underwent RYGB or vertical sleeve gastrectomy (VSG), were subjected to MMTs and GIP infusions pre-surgery and three months post-surgery. GLP-1 infusions were performed in normal weight participants. Cohort 3: Fasting pNT was assessed pre-RYGB (n=161), two months post-RYGB (n=92) and 1-year post-RYGB (n=118) in NG and T2D patients. pNT levels were measured using ELISA.

RESULTS

Reduced fasting and postprandial pNT were evident after VLED and immediately following RYGB. Reintroduction of solid food post-RYGB increased fasting and postprandial pNT. Prior to RYGB, all patients lacked a meal response in pNT, but this was evident post-RYGB/VSG. GIP- or GLP-1 infusion had no effect on pNT levels. Fasting pNT were higher 1-year post-RYGB regardless of glycemic status.

CONCLUSION

RYGB causes a transient reduction in pNT as a consequence of caloric restriction. The RYGB/VSG-induced rise in postprandial pNT is independent of GIP and GLP-1 and higher fasting pNT are maintained one year post-surgically.

Metabolic Effects of Gastric Bypass Surgery: Is It All About Calories?

Bariatric surgery is an efficient method to induce weight loss and also, frequently, remission of type 2 diabetes (T2D). Unpaired studies have shown bariatric surgery and dietary interventions to differentially affect multiple hormonal and metabolic parameters, suggesting that bariatric surgery causes T2D remission at least partially via unique mechanisms. In the current study, plasma metabolite profiling was conducted in patients with (n = 10) and without T2D (n = 9) subjected to Roux-en-Y gastric bypass surgery (RYGB). Mixed-meal tests were conducted at baseline, after the presurgical very-low-calorie diet (VLCD) intervention, immediately after RYGB, and after a 6-week recovery period. Thereby, we could compare fasted and postprandial metabolic consequences of RYGB and VLCD in the same patients. VLCD yielded a pronounced increase in fasting acylcarnitine levels, whereas RYGB, both immediately and after a recovery period, resulted in a smaller but opposite effect. Furthermore, we observed profound changes in lipid metabolism following VLCD but not in response to RYGB. Most changes previously associated with RYGB were found to be consequences of the presurgical dietary intervention. Overall, our results question previous findings of unique metabolic effects of RYGB and suggest that the effect of RYGB on the metabolite profile is mainly attributed to caloric restriction.

Using Contingent Reinforcement to Augment Muscle Activation After Perinatal Brachial Plexus Injury: A Pilot Study

AIM

Examine the feasibility of increasing muscle activation with electromyographically (EMG)-triggered musical-video as reinforcement for children with perinatal brachial plexus injury (PBPI).

METHODS

Six children with PBPI (9.3 ± 6.3 months; 5 female, 1 male) and 13 typically developing (TD) controls (7.8 ± 3.5 months; 4 female, 9 males) participated. The left arm was affected in 5/6 children with PBPI. We recorded the integral (Vs) of biceps activation with surface EMG during two conditions per arm in one session: (1) 100 second (s) baseline without reinforcement and (2) 300 s reinforcement (musical-video triggered to play with biceps activation above threshold [V]). We examined the relation between the mean integral with reinforcement and hand preference.

RESULTS

Mean biceps activation significantly increased from baseline in the affected arm of the group with PBPI by the 2nd (p < .008) and 3rd (p < .0004) 100 s intervals of reinforcement. Six of 6 children with PBPI and 12/13 TD controls increased activation in at least one arm. A lower integral was linked with hand preference for the unaffected right side in the PBPI group.

CONCLUSION

This study supports contingent reinforcement as a feasible method to increase muscle activation. Future work will examine training dose and intensity to increase arm function.

Changes in seroprevalence to four herpesviruses over 30 years in Swedish children aged 9–12 years

BACKGROUND

Changing social conditions and life-styles in Sweden may have affected the spread of varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV).

OBJECTIVES

To study possible changes over 30 years in prevalence of antibodies against VZV, HSV, CMV, and EBV in Swedish children, using modern serological methods.

STUDY DESIGN

Serum samples from 819 Swedish children who were 9-12 years old in 1967-1968, in 1977-1978 (two cohorts), and in 1997, respectively, were examined. IgG antibodies against VZV, HSV, and CMV were measured by well validated enzyme-linked immunosorbent assays and against EBV by indirect immunoflourescense.

RESULTS

The seropositivity for VZV for 9-12 years old children was 50% in 1967-1968, 74-82% in 1977-1978, and 98% in 1997. The corresponding figures were 31%, 53%, 50%, and 58% for CMV, 35%, 35%, 32%, and 38% for HSV, and 64% in 1967-1968 and in 1977-1978 (both cohorts), and 62% in 1997 for EBV.

CONCLUSIONS

The seroprevalence for VZV increased significantly from 1967-1968 to 1997, and there was also a significant but smaller increase in the CMV seroprevalence, while seroprevalence to HSV and EBV remained relatively stable.

Effect of drying rate on porosity and tabletting behaviour of cellulose pellets

The purpose of this study was to investigate the effect of drying rate during static drying on certain physical properties of pellets. Pellets were prepared from microcrystalline cellulose by granulation with different agglomeration liquids (various ethanol/water ratios) and thereafter dried without agitation at different drying rates. The dry pellets were characterised with respect to their shape, porosity, and compression shear strength and the tensile strength of tablets formed from pellets with low and high drying rates was determined. Drying of the pellets occurred at a falling rate and the reduction in liquid content with time obeyed a first order type of relationship. An increased drying rate did not affect the shape and surface texture of the dried pellets and did not cause them to fracture. However, the drying conditions did affect pellet porosity, with an increased drying rate resulting in more porous pellets. Through a relationship with pellet porosity, the drying rate also affected the deformability of the pellets (as assessed from Kawakita 1/b values) and their ability to form tablets. Owing to a strong effect of porosity on pellet compactability, marked changes in tablet tensile strength with variations in drying rate may be obtained.

Drying behaviour of two sets of microcrystalline cellulose pellets

The objective was to study contraction and densification of two sets of microcrystalline cellulose pellets, prepared using water (W) or a 25/75% w/w water/ethanol (W/E) mixture, during drying. The pellets were dried on microscope slides, photographed and weighed at set times. The porosity of the dry pellets was determined by mercury pycnometry. From pellet size, weight and porosity data, contraction and densification of the pellets and the relationship of these to the liquid content of the pellets during drying were calculated. Both types of pellets contracted and densified during drying. The initial porosity was similar for both types, but the final porosity of the dry pellets was higher for the W/E pellets. Thus, the difference in final pellet porosity between the two types was caused by a difference in densification during drying rather than a different degree of densification during the pelletisation procedure. The contraction rate and the relationships between contraction and the volume of removed liquid, and contraction and the degree of liquid saturation differed between the two types of pellet. The difference in drying behaviour between the two types of pellets can be explained by a liquid related change in both contraction driving force and contraction counteracting force or by a different contraction mechanism.