GPR40 is partially required for insulin secretion following activation of beta3-adrenergic receptors

The free fatty acid (FFA) receptor GPR40, expressed by pancreatic beta-cells, may be responsible for insulin release following beta(3) adrenoceptor (Adrb3) activation. To test this hypothesis, we first studied the effects of Adrb3 agonists SR58611A and CL316,243 in GPR40 knockout (GPR40(-/-)) mice. Both drugs increased blood FFA levels in wild-type (GPR40(+/+)) and GPR40(-/-) mice, indicating that lipolysis is not GPR40-dependent. However, the magnitude of the insulin response after agonist treatment was decreased by approximately 50% in GPR40(-/-) mice. Analysis of the time-course revealed that the change in FFAs (5-10 min post-treatment) in response to SR58611A preceded insulin secretion (10-15 min post-treatment). While reduced by agonist treatment, glucose levels in GPR40(-/-) mice remained significantly higher than in GPR40(+/+) mice. Energy expenditure, food intake, or body weight was not affected in GPR40(-/-) mice, whereas SR58611A increased energy metabolism. Furthermore, CL316,243 did not potentiate glucose-stimulated insulin secretion in isolated mouse islets or activate a cAMP reporter in transgenic mice. Our data indicate that insulin secretion, a secondary event following stimulation of Adrb3 receptors, is partially mediated by GPR40 and suggest that GPR40 is integral to the anti-diabetes effects of Adrb3 agonists.

Effects of neurotensin-2 receptor deletion on sensorimotor gating and locomotor activity

Endogenous neurotensin (NT) has been implicated in brain processes relevant to schizophrenia as well as the therapeutic effects of antipsychotic drugs (APDs) used to treat this disorder. Converging evidence suggests that NT1 receptors mediate the antipsychotic-like effects of NT, such as prepulse inhibition (PPI) elevation. However, the role of NT2 receptors in these effects is not known. To investigate the contribution of NT2 receptors to the regulation of PPI, we measured baseline PPI and acoustic startle response (ASR), in male and female wild type (WT) and NT2 knockout (KO) mice. For comparison, we also measured locomotor activity. Baseline PPI was significantly elevated in both male (P<0.01) and female (P<0.01) NT2 KO compared to WT mice, while ASR was significantly decreased in KO mice of both genders (P<0.01). In contrast, female but not male KO mice exhibited significantly less baseline ambulations (P<0.05). These data support the regulation of baseline PPI, ASR and locomotor activity by endogenous NT acting at the NT2 receptor. Further studies investigating the role of NT2 receptors in the modulation of APD-like effects are warranted.

[Anthraquinone contents in five processed products from Rheum palamatum]

OBJECTIVE

To compare the contents of five anthraquinone components in five different processed products from Rheum palamatum.

METHOD

The contents of aleo-emodin, rhein, emodin, chrysophanol and physcion were determined simultaneously by HPLC on plogilent TC-C18 (2) column at 35 degrees C with the methanol-0.1% phosphoric acid (85: 15). The detection wavelength was set at 254 nm and the flow rate was 1.0 mL x min(-1).

RESULT

The obtained linearity of the five components was better over 0.999 9 and the average recoveries were 96.44%, 98.11%, 99.30%, 98.00% and 97.86%, respectively.

CONCLUSION

The results showed the remarkable variation regulations show in the five different processed products. Compared to the no-parched pieces, the contents of the five anthraquinone components have evidently increased in the braising with liquor and the charring products, and reduced in the vinegar and the liquor sauted pieces.

Involvement of the neurotensin receptor 1 in the behavioral effects of two neurotensin agonists, NT-2 and NT69L: lack of hypothermic, antinociceptive and antipsychotic actions in receptor knockout mice

Neurotensin (NT) is a neuropeptide implicated in the pathophysiology of schizophrenia and in mediating the efficacy of antipsychotic drugs. NT is also involved in the regulation of body temperature and pain sensitivity. Using neurotensin receptor 1 (NTR1) knockout (KO) and wild-type (WT) mice, these studies evaluated the involvement of NTR1 in the behavioral responses produced by peripheral administration of NT agonists (NT-2 and NT69L). Animals were characterized in paradigms designed to assess hypothermia, antinociception, and antipsychotic-like effects. Under basal conditions, there were no phenotypic differences between NTR1 KO and WT mice. In WT mice, both NTR1 agonists decreased core body temperature (active doses in mg/kg, i.p., for NT-2 and NT69L, respectively: 1 and 3), increased tail withdrawal latencies (1 and 3), produced decreased spontaneous climbing (0.1, 0.3, 1 and 1, 3, 10) and reversed apomorphine-induced climbing (0.3, 1 and 1, 3). In contrast, none of the effects of either agonist were present in KO mice. These results suggest that NTR1: (1) does not play a major role in the control of basal thermoregulation, nociception or psychomotor stimulation in mice (barring possible developmental plasticity), (2) does mediate these behavioral responses to NT agonists, and (3) may play a role in the potential antipsychotic effects of these agonists.

[Identification and comparison of constituents in HPLC fingerprint of five Chinese herbal pieces from Rheum palamatum]

OBJECTIVE

To identificate and compare constituents in the HPLC fingerprint of five Chinese herbal pieces from Radix et Rhizoma Rhei.

METHOD

HPLC analysis was carried out with methyl alcohol 1% glacial acetic acid as gradient elution, changes in five Chinese herbal pieces and medicinal material under 280 nm and 430 nm were compared.

RESULT

HPLC fingerprints of the no-parched pieces, the liquor and the vinegar roasts pieces were similar, 24 peaks were identified under 280 nm 19 or 22 peaks could be indicated in the braising with liquor and the charring respectively. Under 430 nm, 8 peaks were identified except the braising with liquor.

CONCLUSION

HPLC fingerprints of the no-parched pieces, the liquor and the vinegar roasts pieces are similar while the changes on chemical composition and the content in braising with liquor and the charring are remarkable.

[Comparson study of two types of constituents in seeds of Cassia obtusifolia before and after roasted]

OBJECTIVE

To establish methods of RP-HPLC respectively for content-determination of two types of constituents in the Cassia obtusifolia respectively, and tp determine the constituents between the raw and roasted seeds of C. obtusifolia in order to distinguish the difference of those seeds.

METHOD

HPLC systems consisted of Alltima C18 (4.6 mm x 150 mm, 5 microm), column temperature at 30 degrees C, flow rate of 1.0 mL x min(-1). Two different mobile phases and detection wavelengths: I , ACN-THF-0.1% H3 PO4 (17 : 3:80), 278 nm; II , MeOH-0.1% H3PO4 (79:21), 254 nm. Analyzed and compared the content of the two types of constituents between the raw and roasted seeds of C. obtusifolia.

RESULT

The calibrate curves of 5 constituents were linear (r > 0.999 7). The precision and repeatability were perfect (RSD < 1.6%, 1.8%). The samples were stabile during 24 h.

CONCLUSION

The study provide a better universal reference for evaluating and controlling the quality of C. obtusifolia pieces.

[Comparison on the HPLC fingerprint of Cassia obtusifolia between the raw and roasted seeds]

OBJECTIVE

To establish HPLC fingerprint for the identification of Cassia obtusifolia and compare chemical constituents of the raw and roasted seeds of C. obtusifolia.

METHOD

Chromatographic fingerprint of C. obtusifolia was investigated by RP-HPLC and the gradient elution mode was applied to chromatographic separation. Data were analyzed by fingerprint similarity evaluation software to compare the similarity of the samples for identifying the main chromatographic peaks furthermore.

RESULT

Having compared the HPLC fingerprint of the raw and roasted seeds of C. obtusifolia were compared preliminarily, and 12 main chromatographic peaks were identified.

CONCLUSION

HPLC method can be used in quality control and identification of the raw and roasted seeds of C. obtusifolia.

[Studies on chemical constituents of roasted seeds of Cassia obtusifolia]

OBJECTIVE

To investigate the chemical constituents of the roasted seeds of Cassia obtusifolia to illuminate the change of its effective components before and after roasted.

METHOD

Compounds were separated by silica gel chromatography, and their structures were evaluated by spectral analysis and chemical evidence.

RESULT

Seven compounds were isolated from the ethanol extract. Their structures were identified as chrysophanol (1), physcion (2), 8-methoxylchrysophanol (3), beta-sitosterol (4), emodin (5), obtusin (6) and obtusifolin-2-O-beta-D-(6'-O-acetyl) glucopyranside (7).

CONCLUSION

Compounds 1-7 were isolated from the roasted seeds of C. obtusifolia for the first time, and compound 7 was a new compound.

[Isolation-preparation and determination of chromones from Saposhnikovia divaricata]

OBJECTIVE

To compare the contents of chromones in the different isolation and purification procedures from Saposhnikovia divaricata.

METHOD

The separation of six chromones was determined simultaneously by HPLC on a Kromasil C18 column at 35 degrees C with the methanol-0.1% phosphoric acid in gradient elution as the mobile phrase. The detection wavelength was set at 254 nm and the flow rate was 1.0 mL x min(-1).

RESULT

All the obtained correlation coefficient of the six components was over 0.9995 and the average recoveries were not less than 97% (RSD <5%), respectively.

CONCLUSION

The method is simple, accurate with good reproducibility. Results showed the better preparation procedure is water-decoction and ethanol-precipitation with resin separation and silica gel purification.

[Content comparison of diterpenoid pigments in different processed products of Gardenia jasminoides]

OBJECTIVE

To compare the contents of diterpenoid pigments in the different processed products of Gardenia jasminoides.

METHOD

The separation of Crocin 1, Crocin 2, Crocin 3, Crocetin were determined simultaneously by HPLC on a kromasil C18 column at 35 degrees C with the m methanol-acetonitrile-0.3% formic acid anhydrous in gradient elution as the mobile phrase. The detection wavelength was set at 440 nm and the flow rate was 1.0 mL x min(-1).

RESULT

The obtained linearity of the four components was better over 0.9995 and the average recoveries were 97.77%, 100.05% , 98.40%, 101.02%, respectively.

CONCLUSION

The method is simple, accurate with good reproducibility. The results showed that the remarkable variation regulations appear among the different processed products.

[Comparative studies on contents of iridoid in processed products from Gardenia jasminoides]

OBJECTIVE

To compare the contents of iridoid in the different processed products from Gardenia jasminoides.

METHOD

Contents of geniposide and genipin gentiobioside in products were determined simultaneously by HPLC. A kromasil C18 column at 35 degrees C was used with the acetonitrile-0.3% formic acid anhydrous (12:88) as the mobile phrase. The detection wavelength was set at 238 nm and the flow rate was 1.0 mL x min(-1).

RESULT

The obtained linearity of the two components was good with that the relative coefficients (r) were over 0.9994 and the average recoveries were 101.8%, 99.1%, respectively.

CONCLUSION

The method is simple, accurate with good reproducibility. The results showed contents of two components are difference in the different processed products.

A neural network method for detection of obstructive sleep apnea and narcolepsy based on pupil size and EEG

Electroencephalogram (EEG) is able to indicate states of mental activity ranging from concentrated cognitive efforts to sleepiness. Such mental activity can be reflected by EEG energy. In particular, intrusion of EEG theta wave activity into the beta activity of active wakefulness has been interpreted as ensuing sleepiness. Pupil behavior can also provide information regarding alertness. This paper develops an innovative signal classification method that is capable of differentiating subjects with sleep disorders which cause excessive daytime sleepiness (EDS) from normal control subjects who do not have a sleep disorder based on EEG and pupil size. Subjects with sleep disorders include persons with untreated obstructive sleep apnea (OSA) and narcolepsy. The Yoss pupil staging rule is used to scale levels of wakefulness and at the same time theta energy ratios are calculated from the same 2-s sliding windows by Fourier or wavelet transforms. Then, an artificial neural network (NN) of modified adaptive resonance theory (ART2) is utilized to identify the two groups within a combined group of subjects including those with OSA and healthy controls. This grouping from the NN is then compared with the actual diagnostic classification of subjects as OSA or controls and is found to be 91% accurate in differentiating between the two groups. The same algorithm results in 90% correct differentiation between narcoleptic and control subjects.

Test of marginal compatibility and smoothing methods for exchangeable binary data with unequal cluster sizes

Exchangeable binary data are often collected in developmental toxicity and other studies, and a whole host of parametric distributions for fitting this kind of data have been proposed in the literature. While these distributions can be matched to have the same marginal probability and intra-cluster correlation, they can be quite different in terms of shape and higher-order quantities of interest such as the litter-level risk of having at least one malformed fetus. A sensible alternative is to fit a saturated model (Bowman and George, 1995, Journal of the American Statistical Association 90, 871-879) using the expectation-maximization (EM) algorithm proposed by Stefanescu and Turnbull (2003, Biometrics 59, 18-24). The assumption of compatibility of marginal distributions is often made to link up the distributions for different cluster sizes so that estimation can be based on the combined data. Stefanescu and Turnbull proposed a modified trend test to test this assumption. Their test, however, fails to take into account the variability of an estimated null expectation and as a result leads to inaccurate p-values. This drawback is rectified in this article. When the data are sparse, the probability function estimated using a saturated model can be very jagged and some kind of smoothing is needed. We extend the penalized likelihood method (Simonoff, 1983, Annals of Statistics 11, 208-218) to the present case of unequal cluster sizes and implement the method using an EM-type algorithm. In the presence of covariate, we propose a penalized kernel method that performs smoothing in both the covariate and response space. The proposed methods are illustrated using several data sets and the sampling and robustness properties of the resulting estimators are evaluated by simulations.

Cbln1 is essential for interaction-dependent secretion of Cbln3

Cbln1 and the orphan glutamate receptor GluRdelta2 are pre- and postsynaptic components, respectively, of a novel transneuronal signaling pathway regulating synapse structure and function. We show here that Cbln1 is secreted from cerebellar granule cells in complex with a related protein, Cbln3. However, cbln1- and cbln3-null mice have different phenotypes and cbln1 cbln3 double-null mice have deficits identical to those of cbln1 knockout mice. The basis for these discordant phenotypes is that Cbln1 and Cbln3 reciprocally regulate each other's degradation and secretion such that cbln1-null mice lack both Cbln1 and Cbln3, whereas cbln3-null mice lack Cbln3 but have an approximately sixfold increase in Cbln1. Unlike Cbln1, Cbln3 cannot form homomeric complexes and is secreted only when bound to Cbln1. Structural modeling and mutation analysis reveal that, by constituting a steric clash that is masked upon binding Cbln1 in a "hide-and-run" mechanism of endoplasmic reticulum retention, a single arginine confers the unique properties of Cbln3.

Mice Lacking Adiponectin Show Decreased Hepatic Insulin Sensitivity and Reduced Responsiveness to Peroxisome Proliferator-activated Receptor γ Agonists

The adipose tissue-derived hormone adiponectin improves insulin sensitivity and its circulating levels are decreased in obesity-induced insulin resistance. Here, we report the generation of a mouse line with a genomic disruption of the adiponectin locus. We aimed to identify whether these mice develop insulin resistance and which are the primary target tissues affected in this model. Using euglycemic/insulin clamp studies, we demonstrate that these mice display severe hepatic but not peripheral insulin resistance. Furthermore, we wanted to test whether the lack of adiponectin magnifies the impairments of glucose homeostasis in the context of a dietary challenge. When exposed to high fat diet, adiponectin null mice rapidly develop glucose intolerance. Specific PPARgamma agonists such as thiazolidinediones (TZDs) improve insulin sensitivity by mechanisms largely unknown. Circulating adiponectin levels are significantly up-regulated in vivo upon activation of PPARgamma. Both TZDs and adiponectin have been shown to activate AMP-activated protein kinase (AMPK) in the same target tissues. We wanted to address whether the ability of TZDs to improve glucose tolerance is dependent on adiponectin and whether this improvement involved AMPK activation. We demonstrate that the ability of PPARgamma agonists to improve glucose tolerance in ob/ob mice lacking adiponectin is diminished. Adiponectin is required for the activation of AMPK upon TZD administration in both liver and muscle. In summary, adiponectin is an important contributor to PPARgamma-mediated improvements in glucose tolerance through mechanisms that involve the activation of the AMPK pathway.

A shared response model for clustered binary data in developmental toxicity studies

Existing distributions for modeling fetal response data in developmental toxicology such as the beta-binomial distribution have a tendency of inflating the probability of no malformed fetuses, and hence understating the risk of having at least one malformed fetus within a litter. As opposed to a shared probability extra-binomial model, we advocate a shared response model that allows a random number of fetuses within the same litter to share a common response. An explicit formula is given for the probability function and graphical plots suggest that it does not suffer from the problem of assigning too much probability to the event of no malformed fetuses. The EM algorithm can be used to estimate the model parameters. Results of a simulation study show that the EM estimates are nearly unbiased and the associated confidence intervals based on the usual standard error estimates have coverage close to the nominal level. Simulation results also suggest that the shared response model estimates of the marginal malformation probabilities are robust to misspecification of the distributional form, but not so for the estimates of intralitter correlation and the litter-level probability of having at least one malformed fetus. The proposed model is fitted to a set of data from the U.S. National Toxicology Program. For the same dose-response relationship, the fit based on the shared response distribution is superior to that based on the beta-binomial, and comparable to that based on the recently proposed q-power distribution (Kuk, 2004, Applied Statistics53, 369-386). An advantage of the shared response model over the q-power distribution is that it is more interpretable and can be extended more easily to the multivariate case. To illustrate this, a bivariate shared response model is fitted to fetal response data involving visceral and skeletal malformation.