Effects of the novel sodium-dependent phosphate cotransporter 2b inhibitor DZ1462 on hyperphosphatemia in chronic kidney disease

BACKGROUND

Serum phosphate levels remain insufficiently controlled in chronic kidney disease (CKD) patients, and novel therapeutic strategies are needed. Blocking intestinal phosphate absorption mediated by sodium-dependent phosphate cotransporter type 2b (NPT2b) holds promise as one such strategy.

METHODS

The in vitro cellular potency of DZ1462 was evaluated using a radioactive Pi uptake assay on stable Chinese hamster ovary (CHO) cell clones transfected with human NPT2b (hNPT2b) or rat NPT2b (rNPT2b). The ability of DZ1462 to inhibit phosphate absorption was studied in vivo in an acute model after oral bolus challenge with 33PO4 and in an adenine-induced chronic hyperphosphatemia rat model. PK and minitox was also evaluated.

RESULTS

The cellular assays with the hNPT2b-CHO and rNPT2b-CHO clones showed that DZ1462 significantly and potently inhibited phosphate uptake. In vivo, in a chronic Pi-fed rat model, DZ1462 effectively inhibited intestinal Pi uptake. In a hyperphosphatemia rat model, DZ1462 significantly inhibited Pi uptake, and DZ1462 in combination with sevelamer had a synergistic effect. The pharmacokinetics (PK) study confirmed that DZ1462 is a gastrointestinal (GI)-restricted compound that can remain in the intestine for a sufficient duration. In addition, DZ1462 also reduced cardiovascular events and ameliorated osteoporosis in a CKD animal model.

CONCLUSIONS

This study revealed that a GI-restricted NPT2b inhibitor DZ1462 potently inhibits NPT2b in vitro and blocks intestinal phosphate uptake in multiple animal models with potential to reduce various cardiovascular events in CKD models. Therefore, DZ1462 may be useful to treat renal disease patients who have shown an unsatisfactory response to phosphate binders.

Structural responses of metallic glasses under neutron irradiation

Seeking nuclear materials that possess a high resistance to particle irradiation damage is a long-standing issue. Permanent defects, induced by irradiation, are primary structural changes, the accumulation of which will lead to structural damage and performance degradation in crystalline materials served in nuclear plants. In this work, structural responses of neutron irradiation in metallic glasses (MGs) have been investigated by making a series of experimental measurements, coupled with simulations in ZrCu amorphous alloys. It is found that, compared with crystalline alloys, MGs have some specific structural responses to neutron irradiation. Although neutron irradiation can induce transient vacancy-like defects in MGs, they are fully annihilated after structural relaxation by rearrangement of free volumes. In addition, the rearrangement of free volumes depends strongly on constituent elements. In particular, the change in free volumes occurs around the Zr atoms, rather than the Cu centers. This implies that there is a feasible strategy for identifying glassy materials with high structural stability against neutron irradiation by tailoring the microstructures, the systems, or the compositions in alloys. This work will shed light on the development of materials with high irradiation resistance.

[Application of chromosomal microarray analysis for fetuses with talipes equinovarus]

OBJECTIVE

To investigate the application of fetuses with talipes equinovarus(TE)using chromosomal microarray analysis(CMA)technology.

METHODS

From May 2012 to June 2015, 54 fetuses were found with TE and with or without other structural anomalies by prenatal ultrasound. Karyotyping was taking for them all, and the fetuses with normal karyotypes took another CMA test. The data were analyzed with CHAS software. Finally all the cases were followed up to know about their pregnancy outcomes.

RESULTS

One of the 54 cases was detected with abnormal karyotype which was trisomy 18(2%, 1/54). CMA was undertaken to the remaining fetuses, they were divided into 2 groups, including isolated TE group(n= 38)and complex TE group(n=15). The detection rate of clinical significant copy number variations(CNV)by CMA was 11%(6/53), while isolated and complex TE group were 5%(2/38)and 4/15, respectively(P= 0.047). Of the 53 cases, 51 cases were successfully followed up. Eleven cases were found without TE after birth, and the false positive rate(FPR)of TE was 22%(11/51).

CONCLUSIONS

Whole-genome high-resolution CMA increased the detection rate by 11% in fetuses with TE. With the FPR and the detection rate of the clinical significant CNV of 2 groups, whole-genome CMA could be recommended to the fetuses with complex TE group but normal karyotypes. A series of ultrasonic tests should be suggested to the isolate TE group, while with the abnormal ultrasound, fetuses would be suggested to have CMA test for decreasing the rates of invasive prenatal diagnosis and FPR.

Swimming exercise ameliorates neurocognitive impairment induced by neonatal exposure to isoflurane and enhances hippocampal histone acetylation in mice

Isoflurane-induced neurocognitive impairment in the developing rodent brain is well documented, and regular physical exercise has been demonstrated to be a viable intervention for some types of neurocognitive impairment. This study was designed to investigate the potential protective effect of swimming exercise on both neurocognitive impairment caused by repeated neonatal exposure to isoflurane and the underlying molecular mechanism. Mice received 0.75% isoflurane exposures for 4h on postnatal days 7, 8, and 9. From the third month after anesthesia, the mice were subjected to regular swimming exercise for 4weeks, followed by a contextual fear condition (CFC) trial. We found that repeated neonatal exposure to isoflurane reduced freezing behavior during CFC testing and deregulated hippocampal histone H4K12 acetylation. Conversely, mice subjected to regular swimming exercise showed enhanced hippocampal H3K9, H4K5, and H4K12 acetylation levels, increased numbers of c-Fos-positive cells 1h after CFC training, and less isoflurane-induced memory impairment. We also observed increases in histone acetylation and of cAMP-response element-binding protein (CREB)-binding protein (CBP) during the swimming exercise program. The results suggest that neonatal isoflurane exposure-induced memory impairment was associated with dysregulation of H4K12 acetylation, which may lead to less hippocampal activation following learning tasks. Swimming exercise was associated with enhanced hippocampal histone acetylation and CBP expression. Exercise most likely ameliorated isoflurane-induced memory impairment by enhancing hippocampal histone acetylation and activating more neuron cells during memory formation.

Platelet parameters and expression of platelet membrane glycoprotein in childhood acute lymphoblastic leukemia

Platelet activation and functional changes were investigated in acute lymphoblastic leukemia (ALL) to provide the basis for early diagnosis and evaluation of curative effect. Platelet parameters, immature platelet fraction (IPF%), immature platelet count (IPC), P-selectin (CD62p) (PAC-1) expression were detected in ALL, ALL-complete remission-induced (CR1), and normal groups with an automatic blood cell analyzer and flow cytometer. CD62p and PAC-1 were higher in the ALL group before adenosine-5-diphosphate (ADP) activation than in the normal group (P < 0.05); PAC-1 expression was higher and lower in the ALL-CR1 group than in normal and ALL groups (P < 0.05), respectively. CD62p and PAC-1 expression was lower in the ALL group than in the normal group after ADP activation (P < 0.05); PAC-1 expression was lower and higher in the ALL-CR1 group than in normal and ALL groups, respectively (P < 0.05). Platelet count (PLT), mean platelet volume (MPV), platelet hematocrit (PCT), and platelet distribution width (PDW) were lower in the ALL group than in the ALL-CR1 group (P < 0.05). PLT, MPV, and PCT did not differ between the ALL-CR1 group and the normal group (P > 0.05). PDW did not differ statistically among all groups (P > 0.05). IPF% and IPC values were higher and lower in the ALL group than in normal and ALL-CR1 groups (P < 0.05), respectively. These did not differ significantly between the normal group and the ALL-CR1 group (P > 0.05). Therefore, ALL patients demonstrate platelet activation and platelet dysfunction; platelet parameters and membrane glycoprotein expression can be used to evaluate the effect of ALL.

Propagation characteristics of a focused laser beam in a strontium barium niobate photorefractive crystal under reverse external electric field

The propagation characteristics of a focused laser beam in a SBN:75 photorefractive crystal strongly depend on the signal-to-background intensity ratio (R=I_s/I_b) under reverse external electric field. In the range 20>R>0.05, the laser beam shows enhanced self-defocusing behavior with increasing external electric field, while it shows self-focusing in the range 0.03>R>0.01. Spatial solitons are observed under a suitable reverse external electric field for R=0.025. A theoretical model is proposed to explain the experimental observations, which suggest a new type of soliton formation due to "enhancement" not "screening" of the external electrical field.

Repression of contexual fear memory induced by isoflurane is accompanied by reduction in histone acetylation and rescued by sodium butyrate

BACKGROUND

Isoflurane produces amnesia in mice during contextual fear conditioning (CFC) trials. Histone acetylation is a form of chromatin modification involved in the transcriptional regulation underlying memory formation. We investigated whether isoflurane-induced repression of contextual fear memory is related to altered histone acetylation in the hippocampus, and whether it can be rescued by the histone deacetylases inhibitor sodium butyrate (SB).

METHODS

Adult C57BL/6 mice were chronically given intraperitoneal injections of SB or vehicle for 28 days. Immediately before CFC training, the mice were exposed to isoflurane or air for 30 min and CFC testing was performed the next day. Hippocampal histone acetylation was analysed 1 h after CFC training. c-Fos, an immediate early gene (IEG) suggested to participate in learning and memory formation, was also investigated at the same timepoint.

RESULTS

Mice exposed to isoflurane showed a reduction in freezing time during the CFC test. These mice also exhibited reduced hippocampal H3K14, H4K5, and H4K12 acetylation 1 h after CFC training, and also decreased c-Fos expression. All of these changes were attenuated in isoflurane-exposed mice that were chronically treated with SB.

CONCLUSIONS

Isoflurane suppresses histone acetylation and down-regulates c-Fos gene expression in CA1 of the hippocampus after CFC training. These changes are associated with isoflurane-induced amnesia. The HDAC inhibitor SB prevented repressed contextual fear memory, presumably by promoting histone acetylation and histone acetylation-mediated gene expression in response to CFC training.

Molecular cloning of rhamnose-binding lectin gene and its promoter region from snakehead Channa argus

Lectins are sugar-binding proteins that mediate pathogen recognition and cell-cell interactions. A rhamnose-binding lectin (RBL) gene and its promoter region have been cloned and characterized from snakehead Channa argus. From the transcription initiation site, snakehead rhamnose-binding lectin (SHL) gene extends 2,382 bp to the end of the 3' untranslated region (UTR), and contains nine exons and eight introns. The open reading frame (ORF) of the SHL transcript has 675 bp which encodes 224 amino acids. The molecular structure of SHL is composed of two tandem repeat carbohydrate recognition domains (CRD) with 35% internal identity. Analysis of the gene organization of SHL indicates that the ancestral gene of RBL may diverge and evolve by exon shuffling and gene duplication, producing new forms to play their own roles in various organisms. The characteristics of SHL gene 5' flanking region are the presence of consensus nuclear factor of interleukin 6 (NF-IL6) and IFN-gamma activation (GAS) sites. The results provide indirect evidence that up-regulation of SHL expression may be induced in response to inflammatory stimuli, such as lipopolysaccharide (LPS), interleukin 6 (IL-6), and interferon gamma (IFN-gamma). The transcript of SHL mRNA was expressed in the head kidney, posterior kidney, spleen, liver, intestine, heart, muscle, and ovary. No tissue-specific expressive pattern is different from reported STLs, WCLs, and PFLs, suggesting that different types of RBLs exist in species-specific fish that have evolved and adapted to their surroundings.

Comparative responses in rare minnow exposed to 17beta-estradiol during different life stages

Present in the excrement of humans and animals, 17beta-estradiol (E(2)) has been detected in the aquatic environment in a range from several nanograms to several hundred nanograms per liter. In this study, the sensitivities of rare minnows during different life stages to E(2) at environmentally relevant (5, 25, and 100 ng l(-1)) and high (1000 ng l(-1)) concentrations were compared using vitellogenin (VTG) and gonad development as biomarkers under semistatic conditions. After 21 days of exposure, VTG concentrations in whole-body homogenates were analyzed; the results indicated that the lowest observed effective concentration for VTG induction was 25 ng l(-1) E(2) in the adult stage, but 100 ng l(-1) E(2) in the larval and juvenile stages. After exposure in the early life stage, the larval and juvenile fish were transferred to clean water until gonad maturation. No significant difference in VTG induction was found between the exposure and control groups in the adults. However, a markedly increased proportion of females and appearance of hermaphrodism were observed in the juvenile-stage group exposed to 25 ng l(-1) E(2). These results showed that VTG induction in the adult stage is more sensitive than in larval and juvenile stages following exposure to E(2). The juvenile stage may be the critical period of gonad development. Sex ratio could be a sensitive biomarker indicating exposure to xenoestrogens in early-life-stage subchronic exposure tests. The results of this study provide useful information for selecting sensitive biomarkers properly in aquatic toxicology testing.

Comparative evaluation of the cerebral state index and the bispectral index during target-controlled infusion of propofol

BACKGROUND

Cerebral state index (CSI) has recently been introduced as an intra-operative monitor of anaesthetic depth. We compared the performance of the CSI to the bispectral index (BIS) in measuring depth of anaesthesia during target-controlled infusion (TCI) of propofol.

METHODS

Twenty Chinese patients undergoing general anaesthesia were recruited. CSI and BIS, and predicted effect-site concentration of propofol were recorded. The level of sedation was tested by Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS) every 20 s during stepwise increase (TCI, 0.5 microg ml(-1)) of propofol. The loss of verbal contact (LVC) and loss of response (LOR) were defined by MOAAS values of 2-3 and less than 2, respectively. Baseline variability and the prediction probability (P(K)) were calculated for the BIS and CSI. The values of BIS(05) and CSI(05), BIS(50) and CSI(50), BIS(95) and CSI(95) were calculated at each end-point (LVC and LOR).

RESULTS

Baseline variability of CSI was more than that of BIS. Both CSI and BIS showed a high prediction probability for the steps awake vs LVC, awake vs LOR, and LVC vs LOR, and good correlations with MOAAS values.

CONCLUSION

Despite larger baseline variation, CSI performed as well as BIS in terms of P(K) values and correlations with step changes in sedation.

[Study of the reproducibility and sensitivity of laser microspectral analysis in argon atmosphere at reduced pressure]

In argon atmosphere at reduced pressure, the spectral analysis reproducibility and sensitivity are experimentally studied with the laser microprobe emission spectral analysis(LMESA) system for the metal alloy standard samples. For the atomic spectral analysis line, the relative standard deviation(RSD) in argon atmosphere at reduced pressure is better than that in air atmosphere. For the ionic spectral analysis line, the RSD is almost the same in both cases. The RSD is strongly affected by the composition of the sample and the concentration of elements. The measured slope of calibration curves for the determination of Cu, Zn and Mg in an aluminum alloy in argon atmosphere is about 1.5-2 times of that in the air atmosphere, which indicates an obvious improvement of the sensitivity and is helpful to expand the dynamic range of the spectral analysis.

[Bcl-2 and bax expression in rat cerebral ischemic preconditioning]

OBJECTIVE

To study the expression of apoptosis regulated genes bcl-2 and bax nocoprotein expression and its significance in rat cerebral ischemic preconditioning.

METHODS

With immunohistochemical assay, bcl-2 and bax expression were studied in rat brains which were divided into four groups: the sham-operation control group, the cerebral ischemic group and the cerebral ischemic preconditioning group.

RESULTS

Bcl-2 oncoprotein was induced in cerebral ischemic preconditioning control group. Bax oncoprotein expression had no obviously difference in four groups.

CONCLUSIONS

The expression of bcl-2 and bax oncoprotein after sublethal ischemic preconditioning might be associated with the preconditioning protection against neuronal damage following subsequent lethal ischemia.

[Study of parturient-controlled epidural blockade for labor analgesia]

To explore the feasibility of parturient-controlled epidural blockade for labor analgesia, 44 primiparas requesting labor analgesia (Group I) were selected for testing the above method according to the ASA (American Society of Anesthesiology) Class I or II. Forty-six primiparas were selected as control (Group II). The conditions of control group were similar to those of Group I in all aspects except labor analgesia. The results showed that in Group I labor pain was significantly relieved 5 minutes after anesthesia, and almost eliminated 15 minutes after anesthesia; 95% parturients achieved adequate analgesia. Systolic pressure, diastolic pressure, heart rate and respiratory rate were significantly decreased 5 minutes after anesthesia but still in normal range. The uterine contraction, labor process, delivery mode, postpartum hemorrhage, side effects and neonatal Apgar's score had no significant difference between the two groups. It is suggested that the parturient-controlled epidural blockade is efficiently applied to labor analgesia.