The objective of this study is to compare the normalized prediction distribution errors (NPDE) and the visual predictive check (VPC) on model evaluation under different study designs. In this study, simulation method was utilized to investigate the capability of NPDE and VPC to evaluate the models. Data from the false models were generated by biased parameter typical value or inaccurate parameter inter-individual variability after single or multiple doses with the same sampling time or multiple doses with varied sampling time, respectively. The results showed that there was no clear statistic test for VPC and it was difficult to make sense of VPC under the multiple doses with varied sampling time. However, there were corresponding statistic tests for NPDE and the factor of study design did not affect NPDE significantly. It suggested that the clinical data and model which VPC was not fit for could be evaluated by NPDE.

Objective To investigate whether cerebral microbleeds (CMBs) can predict hematoma expansion in hypertensive cerebral hemorrhage bleeding.Methods One hundred and forty-four patients with hypertensive cerebral hemorrhage bleeding in 6 hours after the onset of symptom were included.Gradient echo pulse sequence-T2 WI (GRE-T2 WI) and computed tomography (CT) were performed to detect the size of hematoma in half an hour after hospital admission.Based on the performance of GRE-T2 WI,patients were divided into microbleeds group and no microbleeds group.CT was performed 24 and 72 hours later to check whether hematoma was enlarged,the ratio of hematoma enlargement and the increased hematoma volume were compared between 2 groups.Results A variable number of CMBs were found in 74 cases by GRE-T2WI on admission.The hematoma volume was increased in 12.5％ (18/144) of patients by CT 24 hours later,and in 13.9％ (20/144) by CT 72 hours later.The ratio of CMBs in microbleeds group was higher than no microbleeds group significantly (70.0％ (14/20) vs 48.4％ (60/124),x2 =4.221,P ＜0.01).Besides,the ratio of the patients with the increased hematoma volume in microbleeds group was significantly higher than no microbleeds group(17.6％ (13/74) vs 10.0％ (7/70),x2 =3.172,P ＜ 0.05).Logistic multiple regression showed that CMBs was the only risk factor which could enter regression equation (OR=2.213,95％CI 1.320-2.972,P＜0.01).Conclusion CMBs patients with hypertensive cerebral hemorrhage bleeding in GRE-T2WI can predict the high risk of hematoma expansion.

Kv2.1 channel currents in pancreatic beta-cells are thought to contribute to action potential repolarization and thereby modulate insulin secretion. Because of its central role in this important physiological process, Kv2.1 channel is a promising target for the treatment of type 2 diabetes. Jingzhaotoxin-XI (JZTX-XI) is a novel peptide neurotoxin isolated from the venom of the spider Chilobrachys jingzhao. Two-microelectrode voltage clamp experiments had showed that the toxin inhibited Kv2.1 potassium currents expressed in Xenopus Laevis oocytes. In order to investigate the structure-function relationship of JZTX-XI, the natural toxin and a mutant of JZTX-XI in which Arg3 was replaced by Ala, were synthesized by solid-phase chemistry method with Fmoc-protected amino acids on the PS3 automated peptide synthesizer. Reverse-phase high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to monitor the oxidative refolding process of synthetic linear peptides to find the optimal renaturation conditions of these toxins. The experiments also proved that the relative molecular masses of refolded peptides were in accordance with their theoretical molecular masses. RP-HPLC chromatogram of co-injected native and refolded JZTX-XI was a single peak. Under the whole-cell patch-clamp mode, JZTX-XI could completely inhibit hKv2.1 and hNav1.5 channels currents expressed in HEK293T cells with IC50 values of 95.8 nmol/L and 437.1 nmol/L respectively. The mutant R3A-JZTX-XI could also inhibit hKv2.1 and hNav1.5 channel currents expressed in HEK293T cells with IC50 values of 1.22 micromol/L and 1.96 micromol/L respectively. However, the prohibitive levels of R3A-JZTX-XI on hKv2.1 and hNav1.5 channels were reduced by about 12.7 times and 4.5 times respectively, indicating that Arg3 was a key amino acid residue relative to the hKv2.1 channel activity of JZTX-XI, but it is also an amino acid residue correlated with the binding activity of JZTX-XI to hNav1.5 channel. Our findings should be helpful to develop JZTX-XI into a molecular probe and drug candidate targeting to Kv2.1 potassium channel in the pancreas.
Animals ; HEK293 Cells ; Humans ; Insulin-Secreting Cells ; metabolism ; Mutant Proteins ; genetics ; pharmacology ; NAV1.5 Voltage-Gated Sodium Channel ; metabolism ; Neurotoxins ; chemical synthesis ; genetics ; pharmacology ; Protein Refolding ; Shab Potassium Channels ; antagonists & inhibitors ; metabolism ; Sodium Channel Blockers ; pharmacology ; Spider Venoms ; genetics ; pharmacology ; Transfection