Early impairment of insulin secretion in rats after surgical trauma

OBJECTIVE: Hyperglycaemia associated with insulin resistance is common after trauma and surgical procedures. Both reduced insulin sensitivity and altered insulin secretion may contribute to the impaired glucose homeostasis. We have demonstrated that skeletal muscle insulin resistance is present 2 h after small intestinal resection in rats. In this study, the aim was to investigate insulin secretion in the same experimental model. DESIGN: Small intestinal resection (5 cm) was performed in adult rats. The control animals underwent anaesthesia only. METHODS: The intravenous glucose tolerance test (IVGTT), the hyperglycaemic clamp and in vitro studies in isolated pancreatic islets were performed after surgery. Concentrations of blood glucose, plasma insulin, corticosterone and interleukin-6 (IL-6) were determined 0-5 h postoperatively. RESULTS: The insulin response in the IVGTT was attenuated 2 h (P<0.05) but not 4 h or during the hyperglycaemic clamp (3.5-4.5 h) postoperatively. Insulin secretion in response to glucose in vitro was decreased 2 h after the surgery (P<0.05), but no change was seen in arginine-stimulated secretion. Plasma levels of corticosterone were increased 3.5-5 h postoperatively (P<0.001-0.05). Increases in IL-6 were also seen postoperatively. CONCLUSION: We demonstrate that glucose-induced, but not arginine-induced, insulin secretion is temporarily impaired after intestinal resection in rats. The later appearance of elevated corticosterone and IL-6 levels, as well as the preservation of the beta-cell inhibition in vitro, argues against the possibility that these two circulating factors are causally responsible for reduced insulin release seen after surgery in this model.     

Lack of compensatory increase in islet blood flow and islet mass in GK rats following 60% partial pancreatectomy

The effects of a 60% partial pancreatectomy were studied in hyperglycemic GK (Goto-Kakizaki) rats. Partial pancreatectomy or a sham operation was performed on 12-week-old female Wistar rats, GK rats or hybrids between male GK rats and female Wistar rats. Measurements of pancreatic blood flow and islet blood flow were performed by a microsphere technique 2 weeks after surgery. Glucose tolerance was decreased in hybrid compared with Wistar rats, and in GK rats compared with both hybrid and Wistar rats before surgery. Partial pancreatectomy induced minor changes in glucose tolerance. Wistar rats had a decreased islet mass following partial pancreatectomy. Both hybrid and GK rats showed a significant decrease in relative islet volume, but only GK rats in total islet mass, compared with Wistar rats 2 weeks after surgery. Pancreatic blood flow and islet blood flow did not significantly differ between sham-operated Wistar, hybrid or GK rats. After partial pancreatectomy, islet blood flow in relation to islet mass increased 3-fold in Wistar rats and 2-fold in hybrid rats. In contrast, GK rats showed no increase in islet blood flow following partial pancreatectomy. It is concluded that compensatory mechanisms after partial pancreatectomy are operating less efficiently in hybrid and GK rats.     

Factors that influence the proclination or retroclination of the lower incisors in children with prolonged thumb-sucking habits

In some children with a prolonged finger-sucking habit, the lower incisors are retroclined, however, proclination of the lower incisors has been frequently observed. The purpose of this study was to determine how such differences develop in the child with a digit-sucking habit. Children with a prolonged thumb-sucking habit and proclination of the lower incisors (Ili/ML > 97 degrees) were cephalometrically and clinically compared to persistent thumb-suckers with retroclined lower incisors (Ili/ML < 89 degrees). In the group with retroclined lower incisors the angle between the thumb and the lower incisors was significantly smaller and the thickness of the lower lip significantly thinner than in the group with proclined incisors. A higher frequency of early loss of deciduous molars was also observed in the group with retroclined incisors. The tightness of the lower lip, early loss of deciduous molars and the angle between the teeth and the thumb are factors which have been identified to influence the inclination of the lower incisors in persistent digit suckers. The majority of children with prolonged thumb-sucking have proclined lower incisors rather than retroclined lower incisors.     

Work stress and low sense of coherence is associated with type 2 diabetes in middle-aged Swedish women

OBJECTIVE: The risk of type 2 diabetes is suggested to be increased for individuals exposed to stress. We analyzed the association of work stress by high demands, low decision latitude, and job strain (combination of high demands and low decision latitude) with type 2 diabetes. We also studied low sense of coherence (SOC) (a factor for successful coping with stressors) in association with type 2 diabetes. Finally, we investigated the combination of SOC and demands or SOC and decision latitude in association with the disease. RESEARCH DESIGN AND METHODS: This cross-sectional study recruited 4821 healthy Swedish women (aged 35-56 years) residing in five municipalities in the Stockholm area. An oral glucose tolerance test identified 52 women with type 2 diabetes. Relative risks (RRs) with 95% CIs were estimated in a logistic multiple regression analysis. RESULTS: No association was found between high demands and type 2 diabetes (RR 1.1 [CI 0.5-2.2]). Low decision latitude was associated with type 2 diabetes with a RR of 2.2 (1.0-4.8). The RR of type 2 diabetes with low SOC was 3.7 (1.2-11.2). The combination of low SOC and low decision latitude was associated with type 2 diabetes with a RR of 2.6 (1.2-5.7). Homeostasis model assessment revealed an association of 4.2 (1.2-15.0) between low SOC and insulin resistance. CONCLUSIONS: This study provided new evidence that stress factors such as low decision latitude at work and low SOC were associated with type 2 diabetes in middle-aged Swedish women.     

The magnitude of bias in a cross-sectional study on lifestyle factors in relation to Type 2 diabetes

AIM: In cross-sectional studies it may be difficult to ascertain the temporal order of exposure and disease, which may have consequences for causal inference. The authors aimed to illustrate the possible magnitude of this potential bias using data from a cross-sectional study on coffee consumption and work stress in relation to type 2 diabetes. METHODS: By a series of computer simulations the authors examined to what extent the observed negative association between type 2 diabetes and high coffee consumption and positive association between type 2 diabetes and high work stress could be due to reverse causality, by assuming that cases changed their exposures in response to development of the disease. RESULTS: If the negative association between coffee and type 2 diabetes was a consequence of reversed causality, 30-40% of the cases would have to decrease their coffee consumption from 5 cups of coffee per day to 3-4 cups per day and from 3-4 cups per day to 2 cups of coffee per day. Moreover, approximately 60% of the cases would have to increase their work stress from low to medium work stress and from medium to high work stress, in order to produce the positive association with diabetes that was observed. CONCLUSION: Even if the type 2 diabetic patients to some extent may have changed their exposure in response to disease development, it seems unlikely that the associations observed between type 2 diabetes, coffee consumption, and work stress are due to this bias.     

Cytokines, matrix metalloproteinases and tissue inhibitor of metalloproteinases-1 in gingival crevicular fluid from patients with Papillon-Lefèvre syndrome

The aim of the present study was to compare concentrations of cytokines, matrix metalloproteinases (MMPs) and a metalloproteinase inhibitor (TIMP-1) in gingival crevicular fluids (GCF) from sites with gingival inflammation in 28 young patients with Papillon-Lefèvre syndrome (PLS), and in age- and gender-matched controls. Each group consisted of 17 females and 11 males with a mean age of 11.0 years (range 4-22 years). In both groups, anterior upper sites with a clinical diagnosis of gingival inflammation and with pockets < or = 3 mm were selected for sampling of GCF, which was carried out with filter disks inserted into the gingival crevice until saturated. The concentrations of cytokines (IL-1alpha, IL-1beta, TNF-alpha, and IL-8), matrix metalloproteinases (MMP-1, MMP-3, MMP-8, and MMP-9), and their tissue inhibitor (TIMP-1) were analysed using commercial ELISA kits. Significantly higher levels of IL-1beta (P < 0.001) and MMP-8 (P < 0.05) were disclosed among the PLS patients compared with their controls, while the opposite was found for IL-8 (P < 0.05) and MMP-1 (P < 0.001). The individual variations were considerable in both groups. When comparing the expression of cytokines, MMPs, and TIMP-1 in PLS patients with clinically active and non-active periodontitis, the non-active PLS patients showed significantly higher values of IL-1beta than the patients with active periodontal disease (ANOVA, P < 0.01). In conclusion, this study was unable to demonstrate a clear-cut pathognomonic expression of cytokines or MMPs in patients with PLS, but further studies on cytokine and MMP output are warranted.     

Circadian rhythms of catecholamine excretion, shooting range performance and self-ratings of fatigue during sleep deprivation.

Circadian rhythms in urinary catecholamine excretion, performance and self-ratings were studied in two experiments with a total of 29 subjects who were deprived of sleep for 72 hr. Adrenaline excretion and fatigue ratings showed the most consistent circadian variations; noradrenaline and performance rhythms were more irregular. The average crest phase for adrenaline excretion was around 1400 hr, for noradrenaline about 0800 hr, for performance 1700 hr and for fatigue 0500 hr. Twenty-four hour levels of performance and 'subjective arousal' decreased over the three days of sleep deprivation, while adrenaline excretion levels increased.     

Serum protein patterns in newly diagnosed type 2 diabetes mellitus--influence of diabetic environment and family history of diabetes

BACKGROUND: Individuals with normal glucose tolerance (NGT) and type 2 diabetes mellitus (T2DM) represent heterogeneous groups with differences in beta-cell function and genetic background. The aim of the present study was to compare serum protein profiles of NGT and T2DM individuals and determine the influence of the genetic background versus diabetic environment on differentially displayed proteins. METHODS: Surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) was used to compare serum protein profiles of NGT persons and T2DM patients. All participants were from the Stockholm Diabetes Prevention Program (SDPP) cohort. They were selected to have high or low beta-cell function (HOMA-beta) and family history of type 2 diabetes (FHD) or not. RESULTS: Eight proteins were found to be elevated and five lowered (p<0.05) in serum of T2DM patients. In a second comparison, the NGT and T2DM groups were divided into persons with FHD and low HOMA-beta and those without FHD and high HOMA-beta. Three proteins were rediscovered and interpreted to be different due to genetic background. Two of these were identified as apolipoprotein C3 (apoC3) and albumin. Ten proteins were interpreted to be not related to FHD, and one of these was identified as transthyretin. CONCLUSIONS: Using the SELDI-technique, serum protein profiles of NGT and T2DM persons with differences in beta-cell function and FHD were compared. The diabetic environment had a major influence on most of these proteins, while FHD was an important factor for apoC3 and albumin.