The elimination rates of intact GIP as well as its primary metabolite, GIP 3-42, are similar in type 2 diabetic patients and healthy subjects

The incretin hormone, glucose-dependent insulinotropic polypeptide (GIP, previously known as gastric inhibitory polypeptide), is rapidly degraded to the biologically inactive metabolite GIP (3-42) in the circulation, but little is known about the kinetics of the intact hormone and the metabolite and whether differences exist between patients with type 2 diabetes mellitus and healthy subjects. We examined eight type 2 diabetic patients (six men, two women); mean (range) age: 59 (48-69) years; BMI: 31.6 (26.0-37.7) kg/m2; HbA1C: 9.0 (8.2-13.2) %; fasting plasma glucose (FPG): 10.0 (8.3-13.2) mmol/l and 8 healthy subjects matched for age, gender and BMI. An intravenous bolus injection of GIP (7.5 nmol) was given and venous blood samples were drawn the following 45 minutes. Peak concentrations of total GIP (intact+metabolite, mean+/-SEM) and intact GIP (in brackets) were 920+/-91 (442+/-52) pmol/l in the type 2 diabetic patients and 775+/-68 (424+/-30) pmol/l in the healthy subjects (NS). GIP was eliminated rapidly with the clearance rate for intact GIP being 2.3+/-0.2 l/min in the type 2 diabetic patients and 2.4+/-0.2 l/min in the healthy subjects (NS). The volumes of distributions were similar in the two groups and ranged from 8 to 21 l per subject. The primary metabolite, GIP 3-42, generated through the action of dipeptidyl peptidase IV (DPP-IV), was eliminated with a mean half-life of 17.5 and 20.5 min in patients and healthy subjects (NS). CONCLUSION: Elimination of GIP is similar in obese type 2 diabetic patients and matched healthy subjects. Differences in elimination of GIP and its primary metabolite, therefore, do not seem to contribute to the defective insulinotropic effect of GIP in type 2 diabetes.     

Pathological and incidental findings on brain MRI in a single-center study of 229 consecutive girls with early or precocious puberty

Central precocious puberty may result from organic brain lesions, but is most frequently of idiopathic origin. Clinical or biochemical factors which could predict a pathological brain MRI in girls with CPP have been searched for. With the recent decline in age at pubertal onset among US and European girls, it has been suggested that only girls with CPP below 6 years of age should have brain MRI performed.

Objective

To evaluate the outcome of brain MRI in girls referred with early signs of puberty in relation to age at presentation as well as clinical and biochemical parameters.

Method

A single-center study of 229 consecutive girls with early or precocious puberty who had brain imaging performed. We evaluated medical history, clinical and biochemical factors, and four groups were defined based on the outcome of their MRI.

Results

Thirteen out of 208 (6.3%) girls with precocious puberty, but no other sign of CNS symptoms, had a pathological brain MRI. Importantly, all 13 girls were above 6 years of age, and 6 girls were even 8–9 years old. Twenty girls (9.6%) had incidental findings on brain MRI. Furthermore, 21 girls had known CNS pathology at time of evaluation. Basal LH was significantly higher in girls with newly diagnosed CNS pathology compared to girls with a non-pathological MRI (p = 0.025); no cut of value was found as values overlapped.

Conclusion

A high frequency of 6–8 year old girls with precocious puberty in our study had a pathological brain MRI, which could not be predicted from any clinical nor biochemical parameters. Thus, we believe that girls with precocious pubertal development of central origin before 8 years of age should continue to be examined by a brain MRI.     

Forty years trends in timing of pubertal growth spurt in 157,000 Danish school children

Background

Entering puberty is an important milestone in reproductive life and secular changes in the timing of puberty may be an important indicator of the general reproductive health in a population. Too early puberty is associated with several psychosocial and health problems. The aim of our study was to determine if the age at onset of pubertal growth spurt (OGS) and at peak height velocity (PHV) during puberty show secular trends during four decades in a large cohort of school children.

Methods and Findings

Annual measurements of height were available in all children born from 1930 to 1969 who attended primary school in the Copenhagen Municipality. 135,223 girls and 21,612 boys fulfilled the criteria for determining age at OGS and age at PHV. These physiological events were used as markers of pubertal development in our computerized method in order to evaluate any secular trends in pubertal maturation during the study period (year of birth 1930 to 1969). In this period, age at OGS declined statistically significantly by 0.2 and 0.4 years in girls and boys, respectively, whereas age at PHV declined statistically significantly by 0.5 and 0.3 years in girls and boys, respectively. The decline was non-linear with a levelling off in the children born between 1940 and 1955. The duration of puberty, as defined by the difference between age at OGS and age at PHV, increased slightly in boys, whereas it decreased in girls.

Conclusion

Our finding of declining age at OGS and at PHV indicates a secular trend towards earlier sexual maturation of Danish children born between 1930 and 1969. Only minor changes were observed in duration of puberty assessed by the difference in ages at OGS and PHV.     

Pigs’ preferences for rooting materials measured in a three-choice maze-test

The aim of this experiment was to investigate pigs’ preferences for rooting materials. Eighteen materials were allocated to six categories each of which consisted of three similar materials based on characteristics such as structure, size of particles, complexity, destructibility and digestibility. Twelve pairs of pigs chose among the three materials of each of the six categories in a balanced design. Within each category each pair was given four instantaneous choices among the three materials in a three-armed maze. ‘No choice’ was scored if the pigs did not enter one of the maze-arms within 90 s. Thus there were four options in each choice situation. The results were analysed using a random utility model incorporating random intercepts to account for the repeated testing of the same animals. The pigs expressed clear preferences within the category EARTH, where compost and peat were preferred to wood-shavings and no choice. In the category CHIP the most probable rank-order was spruce chip, willow chip, fir chip and no choice, while in the category ROUGH the most probable rank-order was maize-silage, grass silage, sugar beets and no choice. However, in these two categories none of the probabilities were sufficiently large to signify a preference for any of the three materials although the probabilities of the ‘no choice’ option were low. The pigs expressed no preferences among any of the four options including ‘no choice’ in the categories TOY (sisal robe, Bite-Rite, wooden beam), HAY (alfalfa hay mixed with straw, seed grass hay, barley straw with under-seed), and STRAW (long straw, chopped straw and straw pellets).     

Human endothelial cells produce a plasminogen activator inhibitor and a tissue-type plasminogen activator-inhibitor complex

Serum-free conditioned media and cell extracts from cultured human umbilical vein endothelial cells were analyzed for plasminogen activator by SDS-polyacrylamide gel electrophoresis and enzymography on fibrin-indicator gels. Active bands of free and complexed tissue-type plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA) were identified by the incorporation of specific antibodies against, respectively, t-PA or u-PA in the indicator gel. The endothelial cells predominantly released a high-molecular-weight t-PA (95000–135000). This t-PA form was converted to M_r-72000 t-PA by 1.5 M NH₄OH/39 mM SDS. A component with high affinity for both t-PA and u-PA could be demonstrated in serum-free conditioned medium and endothelial cell extract. The complex between this component and M_r-72000 t-PA comigrated with high-molecular-weight t-PA. From the increase in M_r of t-PA or u-PA upon complex formation, the M_r of the endothelial cell component was estimated to be 50000–70000. The reaction between t-PA or u-PA and the plasminogen activator-binding component was blocked by 5 mM p-aminobenzamidine, while the complexes, once formed, could be cleaved by 1.5 M NH₄OH/39 mM SDS. These observations indicated that the active center of plasminogen activator was involed in the complex formation. It was further noted that serum-free conditioned medium of endothelial cell extract inhibited plasminogen activator activity when assayed by the fibrin-plate method. Evidence is provided that the plasminogen activator-binding component was different from a number of the known plasma serine proteinase inhibitors, the placenta inhibitor and the fibroblast surface protein, proteinase-nexin. We conclude that cultured endothelial cells produce a rapid inhibitor of u-PA and t-PA as well as a t-PA-inhibitor complex.     

Effect of two pyrimidine analogs on accumulation of tubulin in NHIK 3025 cells

Summary Accumulation of tubulin as compared with the accumulation of total cellular protein in human NHIK 3025 cells treated with the sulfone 2-(2-thenyl)sulfonyl-5-bromopyrimidine (NY 4137) and the sulfoxide 2-(2thenyl)sulfinyl-5-bromopyrimidine (NY 4138), two mitotic inhibitors, were investigated by two-parametric flow cytometry. Following a 4 h treatment with NY 4137 tubulin accumulation is inhibited while total protein continues to accumulate. After treatment for 4h with NY 4138 the accumulation of total protein is approximately constant, while the accumulation of tubulin is reduced although not to the same degree as that found for NY 4137-treated cells. In addition, the percentage tubulin SH-groups (6.89 ± 0.14) remaining after treatment of purified rat brain tubulin with NY 4137 or NY 4138 was determined. Treatment with 0.0125 mM NY 4137 reduced the number of tubulin SH-groups detectable with dithiobis benzoate or from 6.89 ± 0.14 before treatment to about 4 after treatment. However, practically all SH-groups of tubulin remain detectable following treatment with the same concentration of NY 4138. From the results described in this report we infer that NY 4137 binds to tubulin SH-groups and that inhibition of tubulin accumulation follows as a secondary effect.     

The interaction between epiphytic algae, a parasitic fungus and Sphagnum as affected by N and P

We report the effects of fertilisation with N and P on the infection of Sphagnum by its fungal parasite Lyophyllum palustre, the expansion of epiphytic algae and the interaction between the latter two from 1998 to 2001. We added 40 kg N ha⁻¹ yr⁻¹ or 3 kg P ha⁻¹ yr⁻¹ in a full factorial design at 4 field sites. In a greenhouse experiment we reinoculated Sphagnum to verify the identity of the fungus and its necrotic effect on Sphagnum .
Lyophyllum palustre was responsible for the necrosis of Sphagnum in our experiments. Adding N induced complete necrosis of Sphagnum cuspidatum by L. palustre , whereas adding P decreased the area of necrotic tissue. Disease severity was related to the N concentration in the Sphagnum capitula. In Sphagnum magellanicum and S. papillosum , infection with L. palustre resulted in defoliation of stem sections. Adding N stimulated the expansion of algae at all sites, reducing the volume of photosynthetic tissue in Sphagnum. The density of the film of algae in the treatments receiving N was a function of the frequency of defoliated Sphagnum stems.
We conclude that infection with parasitic fungi and, in humid environments, the expansion of epiphytic algae, may aggravate the impact of increased N deposition or of other ecosystem disturbances that affect nutrient availability.     

Minimising immunohistochemical false negative ER classification using a complementary 23 gene expression signature of ER status

Background

Expression of the oestrogen receptor (ER) in breast cancer predicts benefit from endocrine therapy. Minimising the frequency of false negative ER status classification is essential to identify all patients with ER positive breast cancers who should be offered endocrine therapies in order to improve clinical outcome. In routine oncological practice ER status is determined by semi-quantitative methods such as immunohistochemistry (IHC) or other immunoassays in which the ER expression level is compared to an empirical threshold[1], [2]. The clinical relevance of gene expression-based ER subtypes as compared to IHC-based determination has not been systematically evaluated. Here we attempt to reduce the frequency of false negative ER status classification using two gene expression approaches and compare these methods to IHC based ER status in terms of predictive and prognostic concordance with clinical outcome.

Methodology/Principal Findings

Firstly, ER status was discriminated by fitting the bimodal expression of ESR1 to a mixed Gaussian model. The discriminative power of ESR1 suggested bimodal expression as an efficient way to stratify breast cancer; therefore we identified a set of genes whose expression was both strongly bimodal, mimicking ESR expression status, and highly expressed in breast epithelial cell lines, to derive a 23-gene ER expression signature-based classifier. We assessed our classifiers in seven published breast cancer cohorts by comparing the gene expression-based ER status to IHC-based ER status as a predictor of clinical outcome in both untreated and tamoxifen treated cohorts. In untreated breast cancer cohorts, the 23 gene signature-based ER status provided significantly improved prognostic power compared to IHC-based ER status (P = 0.006). In tamoxifen-treated cohorts, the 23 gene ER expression signature predicted clinical outcome (HR = 2.20, P = 0.00035). These complementary ER signature-based strategies estimated that between 15.1% and 21.8% patients of IHC-based negative ER status would be classified with ER positive breast cancer.

Conclusion/Significance

Expression-based ER status classification may complement IHC to minimise false negative ER status classification and optimise patient stratification for endocrine therapies.     

Influence of GLP-1 on Myocardial Glucose Metabolism in Healthy Men during Normo- or Hypoglycemia

Background and Aims

Glucagon-like peptide-1 (GLP-1) may provide beneficial cardiovascular effects, possibly due to enhanced myocardial energetic efficiency by increasing myocardial glucose uptake (MGU). We assessed the effects of GLP-1 on MGU in healthy subjects during normo- and hypoglycemia.

Materials and Methods

We included eighteen healthy men in two randomized, double-blinded, placebo-controlled cross-over studies. MGU was assessed with GLP-1 or saline infusion during pituitary-pancreatic normo- (plasma glucose (PG): 4.5 mM, n = 10) and hypoglycemic clamps (PG: 3.0 mM, n = 8) by positron emission tomography with ¹⁸fluoro-deoxy-glucose (¹⁸F-FDG) as tracer.

Results

In the normoglycemia study mean (± SD) age was 25±3 years, and BMI was 22.6±0.6 kg/m² and in the hypoglycemia study the mean age was 23±2 years with a mean body mass index of 23±2 kg/m². GLP-1 did not change MGU during normoglycemia (mean (+/− SD) 0.15+/−0.04 and 0.16+/−0.03 µmol/g/min, P = 0.46) or during hypoglycemia (0.16+/−0.03 and 0.13+/−0.04 µmol/g/min, P = 0.14). However, the effect of GLP-1 on MGU was negatively correlated to baseline MGU both during normo- and hypoglycemia, (P = 0.006, r² = 0.64 and P = 0.018, r² = 0.64, respectively) and changes in MGU correlated positively with the level of insulin resistance (HOMA 2IR) during hypoglycemia, P = 0.04, r² = 0.54. GLP-1 mediated an increase in circulating glucagon levels at PG levels below 3.5 mM and increased glucose infusion rates during the hypoglycemia study. No differences in other circulating hormones or metabolites were found.

Conclusions

While GLP-1 does not affect overall MGU, GLP-1 induces changes in MGU dependent on baseline MGU such that GLP-1 increases MGU in subjects with low baseline MGU and decreases MGU in subjects with high baseline MGU. GLP-1 preserves MGU during hypoglycemia in insulin resistant subjects.ClinicalTrials.gov registration numbers: {"type":"clinical-trial","attrs":{"text":"NCT00418288","term_id":"NCT00418288"}}NCT00418288: (hypoglycemia) and {"type":"clinical-trial","attrs":{"text":"NCT00256256","term_id":"NCT00256256"}}NCT00256256: (normoglycemia).