A quantitative analysis of attitudes and behaviours concerning sustainable parasite control practices from Scottish sheep farmers

Nematode control in sheep, by strategic use of anthelmintics, is threatened by the emergence of roundworms populations that are resistant to one or more of the currently available drugs. In response to growing concerns of Anthelmintic Resistance (AR) development in UK sheep flocks, the Sustainable Control of Parasites in Sheep (SCOPS) initiative was set up in 2003 in order to promote practical guidelines for producers and advisors. To facilitate the uptake of 'best practice' approaches to nematode management, a comprehensive understanding of the various factors influencing sheep farmers' adoption of the SCOPS principles is required. A telephone survey of 400 Scottish sheep farmers was conducted to elicit attitudes regarding roundworm control, AR and 'best practice' recommendations. A quantitative statistical analysis approach using structural equation modelling was chosen to test the relationships between both observed and latent variables relating to general roundworm control beliefs. A model framework was developed to test the influence of socio-psychological factors on the uptake of sustainable (SCOPS) and known unsustainable (AR selective) roundworm control practices. The analysis identified eleven factors with significant influences on the adoption of SCOPS recommended practices and AR selective practices. Two models established a good fit with the observed data with each model explaining 54% and 47% of the variance in SCOPS and AR selective behaviours, respectively. The key influences toward the adoption of best practice parasite management, as well as demonstrating negative influences on employing AR selective practices were farmer's base line understanding about roundworm control and confirmation about lack of anthelmintic efficacy in a flock. The findings suggest that improving farmers' acceptance and uptake of diagnostic testing and improving underlying knowledge and awareness about nematode control may influence adoption of best practice behaviour.

Envelope surface ultrastructure and specific gravity of artificially fertilized Pacific cod Gadus macrocephalus eggs

The envelope surface ultrastructure and specific gravity of artificially fertilized eggs of the Pacific cod Gadus macrocephalus were examined. The unfertilized, demersal and slightly adhesive eggs of G. macrocephalus were almost spherical and had no oil globules. Wrinkled envelope surface with elaborated hexagonal reticulated patterns and type I micropyle were observed under a scanning electron microscope. The adhesiveness of the eggs was lost at the blastodermal-cap stage after fertilization. The micropylar canal was sealed by secretion of the perivitelline fluid, and the entire surface became rough. Numerous bacilli were deposited at the micropyle and the outer envelope surface at the late germ-ring stage and at the embryo five-eighths around the yolk stage. The micropyle was completely deformed at the embryo seven-eighths around the yolk stage. The specific gravity of the fertilized G. macrocephalus eggs ranged from c. 1·0316 to 1·0454. These values, however, sharply decreased towards the end stages of egg development to produce pelagic larvae. The ultrastructural changes in the micropyle and envelope surface of the G. macrocephalus eggs protected the embryo from microorganism infections and mechanical stress during the long incubation period. The adhesiveness and specific gravity of the eggs influenced their dispersion potential.

Obesity accelerates ovarian follicle development and follicle loss in rats

OBJECTIVE

Studies have shown that excess body fat negatively affects reproductive functions in females. However, whether obesity affects the ovarian follicle development and ovarian lifespan and the underlying mechanism has not been well elucidated. The aim of the present study was to investigate the association between obesity and ovarian follicle development.

METHODS

Adult female Sprague-Dawley rats (n = 36) were randomly divided into three groups: the normal control (NC) group, the caloric restriction (CR) group (fed 70% food of the NC group) and the high-fat diet (HF) group. They were maintained on these regimens for 18 weeks.

RESULTS

The body weight, ovary weight and visceral fat in the HF group were significantly higher than those in the NC group and the CR group at the end of treatment. Histological analysis showed that the HF rats had significantly less number and percentage of primordial follicles, but greater number and percentage of developing and atretic follicles than the NC rats and CR rats. Western blot analysis demonstrated that the level of mTORC1 and p-S6K1 proteins significantly increased in the ovaries of HF rats, whereas that of SIRT1, SIRT6, FOXO3a and NRF-1 decreased compared to the NC rats. In contrast, the expression of mTORC1 and p-S6K1 dramatically declined, while that of SIRT1, SIRT6, FOXO3a and NRF1 increased in the ovaries of CR rats.

CONCLUSIONS

Our study suggests that the HF diet induced obesity may accelerate the ovarian follicle development and rate of follicle loss through activating mTOR and suppressing SIRT1 signaling, thus leading to POF, and that CR may inhibit the activation of primordial follicles, follicular development and loss, thus extending the ovarian lifespan through suppressing mTOR and activating SIRT1 signaling.

A refined-JinQi-JiangTang tablet ameliorates prediabetes by reducing insulin resistance and improving beta cell function in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Refined-JQ (JQ-R) is a mixture of refined extracts from three major herbal components of JinQi-JiangTang tablet: Coptis chinensis (Ranunculaceae), Astragalus membranaceus (Leguminosae), and Lonicera japonica (Caprifoliaceae). Our previous studies have indicated that JQ-R could decrease fasting blood glucose levels in diabetic mice and insulin resistance mice. Investigating the hypoglycemic effect of JQ-R on prediabetes has practical application value for preventing or delaying insulin resistance, impaired glucose tolerance and possibly the development of clinical diabetes.

MATERIALS AND METHODS

The anti-diabetic potential of JQ-R was investigated using a high fat-diet (HFD)-induced obesity mouse model. C57BL/6J mice (HFD-C57 mice) were fed with high-fat diet for 4 months. HFD-C57 mice were treated with either JQ-R (administered intragastrically once daily for 4 weeks) or metformin (as positive control), and the effects of JQ-R on body weight, blood lipids, glucose metabolism, insulin sensitivity, and beta cell function were monitored.

RESULTS

The body weight, serum cholesterol, and the Homeostasis Model Assessment ratio (insulin resistance index) were significantly reduced in JQ-R or metformin-treated mice, and the glucose tolerance was enhanced and insulin response was improved simultaneously. Moreover, both JQ-R and metformin could activate liver glycogen syntheses even under a relatively high glucose loading. Although glyconeogenesis was inhibited in the metformin treated mice, it was not observed in JQ-R treated mice. Similar to metformin, JQ-R could also improve the glucose infusion rate (GIR) in hyperglycemic clamp test. JQ-R was also shown to increase the levels of phosphorylated AMPKα and phosphorylated acetyl CoA carboxylase (ACC), similar to metformin.

CONCLUSION

JQ-R could reduce HFD-induced insulin resistance by regulating glucose and lipid metabolism, increasing insulin sensitivity through activating the AMPK signaling pathway, and subsequently improving β cell function. Therefore, JQ-R may offer an alternative in treating disorders associated with insulin resistance, such as prediabetes and T2DM.

Antisense oligonucleotides on neurobehavior, respiratory, and cardiovascular function, and hERG channel current studies

INTRODUCTION

Safety Pharmacology studies were conducted in mouse, rat, and non-human primate to determine in vivo effects of antisense oligonucleotides (ASOs) on the central nervous system, respiratory system, and cardiovascular system. Effects on the hERG potassium channel current was evaluated in vitro.

METHODS

ASOs contained terminal 2'-O-methoxyethyl nucleotides, central deoxy nucleotides, and a phosphorothioate backbone. Neurobehavior was evaluated by Functional Observatory Battery in rodents. Respiratory function was directly measured in rodents by plethysmograph; respiratory rate and blood gases were measured in monkey. Basic cardiovascular endpoints were measured in rat; cardiovascular evaluation in monkey involved implanted telemetry units. In single and repeat dose studies ASOs were administered by subcutaneous injection at up to 300 mg/kg, 250 mg/kg, and 40 mg/kg in mouse, rat, or monkey, respectively. Assays were performed in HEK293 or CHO-K1 cells, stably transfected with hERG cDNA, at ASO concentrations of up to 300 μM.

RESULTS

No apparent effects were noted for respiratory or CNS function. Continuous monitoring of the cardiovascular system in monkey demonstrated no ASO-related changes in blood pressures, heart rate, or ECG and associated parameters (i.e., QRS duration). Specific assessment of the hERG potassium channel indicated no potential for actions on ventricular repolarization or modest effects only at excessive concentrations.

DISCUSSION

The absence of direct actions on neurobehavior and respiratory function associated with the administration of ASOs in safety pharmacology core battery studies is consistent with published toxicology studies. The combination of in vitro hERG studies and in vivo studies in rat and monkey are consistent with no direct actions by ASOs on cardiac cell function or electrical conduction at relevant concentrations and dose levels. Taken as a whole, dedicated studies focused on the safety pharmacology of specific organ systems do not appear to add significant data for interpretation of potential adverse effects. The need for dedicated studies for future ASOs in the same class is questionable, as a more encompassing data set can be collected in repeat dose and longer-term toxicology studies.

Thyroid hormone improves the mechanical performance of the post-infarcted diabetic myocardium: a response associated with up-regulation of Akt/mTOR and AMPK activation

OBJECTIVE

Thyroid hormone (TH) is shown to be protective against cardiac and pancreatic injury. Thus, this study explored the potential effects of TH treatment on the functional status of the postinfarcted diabetic myocardium. Diabetic patients have worse prognosis after acute myocardial infarction (AMI).

MATERIALS/METHODS

AMI was induced by left coronary ligation in rats previously treated with 35 mg/kg streptozotocin (STZ), (DM-AMI). TH treatment was initiated at 2 weeks after AMI and continued for 6 weeks (DM-AMI+TH), while sham-operated animals served as control (DM-SHAM).

RESULTS

TH treatment increased cardiac mass, improved wall stress and favorably changed cardiac geometry. TH significantly increased echocardiographic left ventricular ejection fraction (LVEF%): [54.2 (6.5) for DM-AMI+TH vs 37 (2.0) for DM-AMI, p<0.05]. TH treatment resulted in significantly increased insulin and decreased glucose levels in serum. The ratios of phosphorylated (p)-Akt/total Akt and p-mTOR/total mTOR were increased 2.0 fold and 2.7 fold in DM-AMI+TH vs DM-AMI respectively, p<0.05. Furthermore, the ratio of p-AMPK/total AMPK was found to be increased 1.6 fold in DM-AMI+TH vs DM-AMI, p<0.05.

CONCLUSION

TH treatment improved the mechanical performance of the post-infarcted myocardium in rats with STZ-induced diabetes, an effect which was associated with Akt/mTOR and AMPK activation.

Different effects of the NMDA receptor antagonists ketamine, MK-801, and memantine on postsynaptic density transcripts and their topography: role of Homer signaling, and implications for novel antipsychotic and pro-cognitive targets in psychosis

Administration of NMDA receptor antagonists, such as ketamine and MK-801, may induce psychotic-like behaviors in preclinical models of schizophrenia. Ketamine has also been observed to exacerbate psychotic symptoms in schizophrenia patients. However, memantine, a non-competitive NMDA receptor antagonist approved for Alzheimer's disease and proposed for antipsychotic augmentation, may challenge this view. To date, the molecular mechanisms by which these NMDA receptor antagonists cause different neurochemical, behavioral, and clinical effects are still a matter of debate. Here, we investigated by molecular imaging whether these agents could differently modulate gene expression and topographical distribution of glutamatergic postsynaptic density (PSD) proteins. We focused on Homer1a/Homer1b/PSD-95 signaling network, which may be implicated in glutamate-dependent synaptic plasticity, as well as in psychosis pathophysiology and treatment. Ketamine (25 and 50mg/kg) and MK-801 (0.8mg/kg) significantly induced the transcripts of immediate-early genes (Arc, c-fos, and Homer1a) in cortical regions compared to vehicle, whereas they reduced Homer1b and PSD-95 expression in cortical and striatal regions. Differently, memantine (5mg/kg) did not increase Homer1a signal compared to vehicle, whereas it induced c-fos in the somatosensory and in the medial agranular cortices. Moreover, memantine did not affect Homer1b and PSD-95 expression. When compared to ketamine and MK-801, memantine significantly increased the expression of c-fos, Homer1b and PSD-95. Overall, ketamine and MK-801 prominently increased Homer1a/Homer1b expression ratio, whereas memantine elicited the opposite effect. These data may support the view that ketamine, MK-801 and memantine exert divergent effects on PSD transcripts, which may contribute to their partially different behavioral and clinical effects.

Ezh1 and Ezh2 differentially regulate PSD-95 gene transcription in developing hippocampal neurons

Polycomb Repressive Complex 2 (PRC2) mediates transcriptional silencing by catalyzing histone H3 lysine 27 trimethylation (H3K27me3), but its role in the maturation of postmitotic mammalian neurons remains largely unknown. We report that the PRC2 paralogs Ezh1 and Ezh2 are differentially expressed during hippocampal development. We show that depletion of Ezh2 leads to increased expression of PSD-95, a critical plasticity gene, and that reduced PSD-95 gene transcription is correlated with enrichment of Ezh2 at the PSD-95 gene promoter; however, the H3K27me3 epigenetic mark is not present at the PSD-95 gene promoter, likely due to the antagonizing effects of the H3S28P and H3K27Ac marks and the activity of the H3K27 demethylases JMJD3 and UTX. In contrast, increased PSD-95 gene transcription is accompanied by the presence of Ezh1 and elongation-engaged RNA Polymerase II complexes at the PSD-95 gene promoter, while knock-down of Ezh1 reduces PSD-95 transcription. These results indicate that Ezh1 and Ezh2 have antagonistic roles in regulating PSD-95 transcription.