Evaluation of glycated glucagon-like peptide-1(7-36)amide in intestinal tissue of normal and diabetic animal models

Glucagon-like peptide-1(7-36)amide (tGLP-1) is an important insulin-releasing hormone of the enteroinsular axis which is secreted by endocrine L-cells of the small intestine following nutrient ingestion. The present study has evaluated tGLP-1 in the intestines of normal and diabetic animal models and estimated the proportion present in glycated form. Total immunoreactive tGLP-1 levels in the intestines of hyperglycaemic hydrocortisone-treated rats, streptozotocin-treated mice and ob/ob mice were similar to age-matched controls. Affinity chromatographic separation of glycated and non-glycated proteins in intestinal extracts followed by radioimmunoassay using a fully crossreacting anti-serum demonstrated the presence of glycated tGLP-1 within the intestinal extracts of all control animals (approximately 19%., of total tGLP-1 content). Chemically induced and spontaneous animal models of diabetes were found to possess significantly greater levels of glycated tGLP-1 than controls, corresponding to between 24-71% of the total content. These observations suggest that glycated tGLP-1 may be of physiological significance given that such N-terminal modification confers resistance to DPP IV inactivation and degradation, extending the very short half-life (

Degradation and glycemic effects of His(7)-glucitol glucagon-like peptide-1(7-36)amide in obese diabetic ob/ob mice

Glucagon-like peptide-1(7-36)amide (tGLP-1) has attracted considerable potential as a possible therapeutic agent for type 2 diabetes. However, tGLP-1 is rapidly inactivated in vivo by the exopeptidase dipeptidyl peptidase IV (DPP IV), thereby terminating its insulin releasing activity. The present study has examined the ability of a novel analogue, His(7)-glucitol tGLP-1 to resist plasma degradation and enhance the insulin-releasing and antihyperglycemic activity of the peptide in 20-25-week-old obese diabetic ob/ob mice. Degradation of native tGLP-1 by incubation at 37 degreesC with obese mouse plasma was clearly evident after 3 h (35% intact). After 6 h, more than 87% of tGLP-1 was converted to GLP-1(9-36)amide and two further N-terminal fragments, GLP-1(7-28) and GLP-1(9-28). In contrast, His7-glucitol tGLP-1 was completely resistant to N-terminal degradation. The formation of GLP-1(9-36)amide from native tGLP-1 was almost totally abolished by addition of diprotin A, a specific inhibitor of DPP IV. Effects of tGLP-1 and His7-glucitol tGLP-1 were examined in overnight fasted obese mice following i.p. injection of either peptide (30 nmol/kg) together with glucose (18 mmol/kg) or in association with feeding. Plasma glucose was significantly lower and insulin response greater following administration of His7-glucitol tGLP-1 as compared to glucose alone. Native tGLP-1 lacked antidiabetic effects under the conditions employed, and neither peptide influenced the glucose-lowering action of exogenous insulin (50 units/kg). Twice daily s.c. injection of ob/ob mice with His(7)-glucitol tGLP-1 (10 nmol/kg) for 7 days reduced fasting hyperglycemia and greatly augmented the plasma insulin response to the peptides given in association with feeding. These data demonstrate that His(7)-glucitol tGLP-1 displays resistance to plasma DPP IV degradation and exhibits antihyperglycemic activity and substantially enhanced insulin-releasing action in a commonly used animal model of type 2 diabetes. (C) 2001 Elsevier Science B.V. All rights reserved.

N-terminally modified glucagon-like peptide-1(7-36) amide exhibits resistance to enzymatic degradation while maintaining its antihyperglycaemic activity in vivo

Glucagon-like peptide-1 (7-36)amide (tGLP-1) is inactivated by dipeptidyl peptidase (DPP) IV by removal of the NH2-terminal dipeptide His(7)-Ala(8). We examined the degradation of NH2-terminally modified His(7)-glucitol tGLP-1 and its insulin-releasing and antihyperglycaemic activity in vivo, tGLP-1 was degraded by purified DPP IV after 4 h (43% intact) and after 12 hi 89% was converted to GLP-1(9-36)amide. In contrast > 99% of His(7)-glucitol tGLP-1 remained intact at 12 h. His(7)-glucitol tGLP-1 was similarly resistant to plasma degradation in vitro. His7-glucitol tGLP-1 showed greater resistance to degradation in vivo (92% intact) compared to tGLP-1 (27% intact) 10 min after i.p. administration to Wistar rats. Glucose homeostasis was examined following i.p. injection of both peptides (12 nmol/kg) together with glucose (18 mmol/kg). Plasma glucose concentrations were significantly reduced and insulin concentrations elevated following peptides administration compared with glucose alone. The area under the curve (AUC) for glucose for controls (AUC 691 +/- 35 mM/min) was significantly lower after administration of tGLP-1 and His7-glucitol tGLP-1 (36 and 49% less; AUC; 440 +/- 40 and 353 +/- 31 mM/min, respectively; P

A 330-360 GHz spectral survey of G34.3+0.15 - III. The outer halo

We have undertaken a 330-360 GHz molecular line survey of the halo gas surrounding the hot core associated with G34.26+0.15. In contrast to our molecular line survey of the hot core itself, where 338 lines from at least 38 species were detected, only 18 lines from 9 species were detected in the halo. The lines are mainly single transitions of simple di atomic and triatomic molecules. Lower limits to their column densities have been evaluated by an LTE method. In the case of methanol, where four transitions were detected, the rotation temperature and column density have been evaluated by the rotation diagram technique. We have modified the previous depth-dependent chemical model developed in Paper II to calculate the column densities observed along a general line of sight drawn through the model cloud. The model is also extended to produce beam-averaged column densities for better comparison with those observed. We compare the model column densities with those observed and make recommendations for future depth-dependent chemical modelling of hot cores.

A 330-360 GHz spectral survey of G34.3+0.15 .2. Chemical modelling

We describe a detailed depth-and time-dependent model of the molecular cloud associated with the ultracompact H II region G 34.3+0.15. Previous work on observations of NH3 and CS indicates that the molecular cloud has three distinct physical components:- an ultracompact hot core, a compact hot core and an extended halo. We have used the physical parameters derived from these observations as input to our detailed chemical kinetic modelling. The results of the model calculations are discussed with reference to the different chemistries occuring in each component and are compared with abundances derived from our recent spectral line survey of G 34.3+0.15 (Paper I).

A 330-360 GHz spectral survey of G 34.3+0.15 .1. Data and physical analysis

A 330--360 GHz spectral survey of the hot molecular core associated with the 'cometary' ultracompact HII region G 34.3+/-0.15 observed with the James Clerk Maxwell Telescope has detected 338 spectral lines from at least 35 distinct chemical species plus 19 isotopomers. 70 lines remain unidentified. Chemical abundance and rotation temperature have been determined by rotation diagram analysis for 12 species, and lower limits to abundance found for 38 others.

Effort-reward imbalance at work and the co-occurrence of lifestyle risk factors: cross-sectional survey in a sample of 36,127 public sector employees

Background: In occupational life, a mismatch between high expenditure of effort and receiving few rewards may promote the co-occurrence of lifestyle risk factors, however, there is insufficient evidence to support or refute this hypothesis. The aim of this study is to examine the extent to which the dimensions of the Effort-Reward Imbalance (ERI) model - effort, rewards and ERI - are associated with the co-occurrence of lifestyle risk factors.

NEUROPEPTIDE-Y AND NEUROPEPTIDE-Y 3-36 - ISOLATION FROM HUMAN PANCREATIC ENDOCRINE TUMORS

Using an antiserum raised to the C-terminal region of neuropeptide Y (NPY) which does not cross-react with pancreatic polypeptide (PP), immunoreactivity has been detected in two different endocrine tumours of the human pancreas in concentrations permitting isolation and structural analysis. In a clinically-typical gastrinoma, resected from the head of pancreas, the concentration of NPY immunoreactivity was 3.4 nmol/g. Reverse phase HPLC analysis of extracts of this tumour resolved a single immunoreactive peptide coeluting with synthetic human NPY. The molecular mass of the isolated peptide, determined by mass spectroscopy, was 4270 Da, which was in close agreement with that derived from the deduced primary structure of human tumour NPY (4271.7 Da), obtained by gas-phase sequencing. A somatostatinoma, resected from the region of the ampulla of Vater, contained 3.8 nmol/g of NPY immunoreactivity and isolation of this immunoreactive peptide followed by structural analyses, indicated a molecular structure consistent with NPY 3-36. These data suggest that NPY immunoreactivity detected in human pancreatic endocrine tumours is molecularly heterogenous, a finding which may be of relevance in the symptomatology of such tumours as attenuation of the N-terminus of this peptide generates receptor selectivity.

The Influence of the User in Body-Centric Antennas and Propagation at 3–6 GHz—A Rician K-Factor Approach

We investigate whether the presence of a human body in wearable communications should be considered as part of the radiating structure or as part of the local radio environment. The Rician $K$ -factor was employed as a quantitative measure of the effect of the user's body for five environments and two mounting locations. Presented empirical results indicated that the environment had a greater impact on the $K$-factor values than the position of the transmit antenna for the ultrawideband signals used, confirming that the human body should be considered primarily as part of the overall radiating system when the antenna is worn on the body. Furthermore, independent variations also existed in the $K$-factor values for the differing antenna-body mounting positions, indicating that as the position changed, then the radiating effects and the contribution from the body changed. This is significant for ensuring body-antenna systems are accurately modeled in system-level simulations.

A methodological review of the Short Form Health Survey 36 (SF-36) and its derivatives among breast cancer survivors

Purpose: A systematic review of the validity, reliability and sensitivity of the Short Form (SF) health survey measures among breast cancer survivors.
Methods: We searched a number of databases for peer-reviewed papers. The methodological quality of the papers was assessed using the COnsenus-based Standards for the selection of health Measurement INstruments (COSMIN).
Results: The review identified seven papers that assessed the psychometric properties of the SF-36 (n = 5), partial SF-36 (n = 1) and SF-12 (n = 1) among breast cancer survivors. Internal consistency scores for the SF measures ranged from acceptable to good across a range of language and ethnic sub-groups. The SF-36 demonstrated good convergent validity with respective subscales of the Functional Assessment of Cancer Treatment—General scale and two lymphedema-specific measures. Divergent validity between the SF-36 and Lymph-ICF was modest. The SF-36 demonstrated good factor structure in the total breast cancer survivor study samples. However, the factor structure appeared to differ between specific language and ethnic sub-groups. The SF-36 discriminated between survivors who reported or did not report symptoms on the Breast Cancer Prevention Trial Symptom Checklist and SF-36 physical sub-scales, but not mental sub-scales, discriminated between survivors with or without lymphedema. Methodological quality scores varied between and within papers.
Conclusion: Short Form measures appear to provide a reliable and valid indication of general health status among breast cancer survivors though the limited data suggests that particular caution is required when interpreting scores provided by non-English language groups. Further research is required to test the sensitivity or responsiveness of the measure.