Gingipains disrupt F-actin and cause osteoblast apoptosis via integrin β1

BACKGROUND AND OBJECTIVE

The aim of this study was to explore the cellular mechanisms underlying gingipain-caused changes in cell morphology and apoptosis of osteoblasts.

MATERIAL AND METHODS

Human calvarial osteoblasts and mouse osteoblasts MC3T3-E1 were treated with gingipain extracts from Porphyromonas gingivalis stain W83. Apoptosis was detected with annexin V and propidium iodide flow cytometry analysis or terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling staining. F-actin was determined by immunostaining. Western blotting was used to detect protein expression. Knocking down and overexpressing approaches were used to determine the role of integrin β1.

RESULTS

Osteoblasts exposed to gingipain extracts displayed increased apoptosis, accompanied by loss of F-actin integrity and cell shrinkage. The effects of gingipain extracts were abolished by the cysteine protease inhibitor N-tosyl-l-lysyl chloromethyl-ketone. Notably, gingipain extracts resulted in reduction of integrin β1, accompanied by diminished active RhoA whereas without effect on the total RhoA. Knockdown of integrin β1 resembled those seen in gingipain-treated osteoblasts. By contrast, the effects of gingipain extracts were abrogated by either overexpression of integrin β1 or presence of RhoA agonist CN03.

CONCLUSION

Gingipain-induced F-actin disruption and apoptosis are mediated by the degradation of integrin β1 and inhibition of RhoA activity, which account for osteoblast apoptosis.

Comparison of nitrogen utilization and urea kinetics between yaks (Bos grunniens) and indigenous cattle (Bos taurus)

Under traditional management on the Qinghai-Tibetan Plateau, yaks () graze only on natural pasture without supplements and are forced to cope with sparse forage of low N content, especially in winter. In contrast, indigenous Tibetan yellow cattle () require supplements during the cold season. We hypothesized that, in response to harsh conditions, yaks cope with low N intakes better than cattle. To test this hypothesis, a study of whole-body N retention and urea kinetics was conducted in 2 concurrent 4 × 4 Latin squares, with 1 square using yaks and 1 square using cattle. Four isocaloric forage-concentrate diets differing in N concentrations (10.3, 19.5, 28.5, and 37.6 g N/kg DM) were formulated, and by design, DMI were similar between species and across diets. Urea kinetics were determined with continuous intravenous infusion of NN urea for 104 h, and total urine and feces were concomitantly collected. Urea production, urea recycling to the gut, and ruminal microbial protein synthesis all linearly increased ( < 0.001) with increasing dietary N in both yaks and cattle. Urinary N excretion was less ( = 0.04) and N retention was greater ( = 0.01) in yaks than in cattle. Urea production was greater in yaks than in cattle at the 3 lowest N diets but greater in cattle than in yaks at the highest N diet (species × diet, < 0.02). Urea N recycled to the gut ( < 0.001), recycled urea N captured by ruminal bacteria ( < 0.001), and ruminal microbial protein production ( = 0.05) were greater in yaks than in cattle. No more than 12% of urea recycling was through saliva, with no difference between species ( = 0.61). Glomerular filtration rate was lower ( = 0.05) in yaks than in cattle. The higher urea recycling and greater capture of recycled urea by ruminal microbes in yaks than in cattle suggest that yaks use mechanisms to utilize dietary N more efficiently than cattle, which may partially explain the better survival of yaks than cattle when fed low-N diets.

[Long-term outcomes of implanting drug-eluting stents for unprotected left main coronary artery disease patients with left ventricular systolic dysfunction]

Objective: To analyze the clinical characteristics and prognosis of implanting drug-eluting stents (DES) for unprotected left main (ULM) coronary artery disease patients with left ventricular systolic dysfunction (LVSD). Methods: A total of 511 ULM coronary artery disease patients who underwent DES implantation from January 2005 to January 2012 in Department of Cardiology, Beijing Anzhen Hospital were included in the study. Based on left ventricular ejection fraction (LVEF), the patients were divided into three groups: LVEF≤40% (n=104), 41%≤LVEF≤49% (n=137), and LVEF≥50% (n=270). The clinical characteristics of patients undergoing DES implantation were retrospectively compared, and the effects of LVSD on ULM coronary artery disease were analyzed. Results: After comparison of clinical baseline data among three different LVEF groups, the incidence of peripheral vascular diseases, old myocardial infarction (OMI), multi-vessel lesions, complete revascularization and chronic total occlusion (CTO) was statistically different (P=0.002, P<0.001, P<0.001, P=0.049, P=0.001, respectively). However, there was no significant difference in the incidence of other clinical characteristics (all P>0.05). In terms of survival analysis, total mortality and cardiac mortality were both remarkably higher in LVEF≤40% group than those in LVEF≥50% group (both P<0.001). There was no statistical difference of total mortality between 41%≤LVEF≤49% group and LVEF≥50% group (P>0.05), while cardiac mortality was higher in LVEF≥50% group (P=0.027) . Besides, there was no significant difference among three groups in major adverse cardiac and cerebral events (MACCE), myocardial infarction(MI), cerebral infarction and target vessel revascularization (TVR) (all P>0.05). After adjusting for multiple clinical factors, total mortality and cardiac mortality were both remarkably higher in LVEF≤40% group than those in LVEF≥50% group (P=0.002, P<0.001), while there were no statistical differences of total mortality and cardiac mortality between 41%≤LVEF≤49% group and LVEF≥50% group (both P>0.05). In terms of MACCE, MI, cerebral infarction and TVR, there were also no significant differences among three groups (all P>0.05). Conclusion: For ULM coronary artery disease patients with LVSD, implanting DES is safe and effective, but for those with severe LVSD (LVEF≤40%), DES implantation showed an increased risk of long-term death and therefore should be selected with great care.

[The clinical manifestation and analysis of eosinophilic granulomatous vasculitis]

OBJECTIVE

To evaluate the clinical features, treatment and prognosis of Eosinophilic Granulomatous Vasculitis.

METHODS

We analyzed retrospectively the clinical and laboratory features, treatment and prognosis of 43 patients with Eosinophilic Granulomatous Vasculitis who admitted to the Department of Rheumatology of the First Affiliated University Hospital of Sun Yat-sen University between 2005 and 2014.

RESULTS

Of the 43 patients, 31 patients (72.1%) had allergic symptoms in the disease course and 16 patients (37.2%) had asthma and lung wheezing sound when performing the physical examination.Organs involvements included skin, acra, lung, kidney, central and peripheral nervous system, digestive system and heart.Positive antineutrophilic cytoplasmic antibody (ANCA) which mainly with MPO-ANCA was found in 18 patients (41.9%). Thirty-nine patients (90.7%)had high blood eosinophil level while all patients (100%) had elevated IgE.Two patients died of multiple organ failure in their acute phase, and the others had favorable prognosis after receiving the treatment of glucocorticoid combine with cyclophosphamide or methotrexate.

CONCLUSIONS

Eosinophilic Granulomatous Vasculitiscould make damage to organs and tissues.Only 72.1% patients had allergic symptoms and 37.2% patients had asthma and lung wheezing sound.More than half patients have the negative ANCA.Glucocorticoidcombine with cyclophosphamide or methotrexate can achieve satisfactory therapeutic effects.

Endocannabinoid activation of CB1 receptors contributes to long-lasting reversal of neuropathic pain by repetitive spinal cord stimulation

BACKGROUND

Spinal cord stimulation (SCS) has been shown to be effective in the management of certain neuropathic pain conditions, however, the underlying mechanisms are incompletely understood. In this study, we investigated repetitive SCS in a rodent neuropathic pain model, revealing long-lasting and incremental attenuation of hyperalgesia and a mechanism of action involving endocannabinoids.

METHOD

Animals were implanted with monopolar electrodes at the time of partial sciatic nerve injury. Dorsal columns at spinal segments T12/13 were stimulated 3 days later (early SCS), and again at day 7 (late SCS) using low-frequency parameters. Hypersensitivity to cutaneous mechanical stimuli was assessed using von Frey filaments. Pharmacological agents, selected to identify endocannabinoid and opioid involvement, were administered intraperitoneally, 10 min before SCS.

RESULTS

Early SCS caused partial reversal of mechanical hypersensitivity with corresponding changes in the biomarker of central sensitization, [phospho-Tyr¹⁴⁷² ]-GluN2B. The partial reversal of hyperalgesia by early SCS was amplified by co-administration of LY 2183240, an inhibitor of endocannabinoid reuptake/breakdown. This amplification was inhibited by a CB₁ R antagonist, AM251, but not by a CB₂ R antagonist, AM630. Early SCS-induced reversal of hyperalgesia was attenuated by naloxone, indicating a role for opioids. Late SCS resulted in an incremental level of reversal of hyperalgesia, which was inhibited by AM251, but not by CB₂ or opioid receptor antagonists.

CONCLUSION

The endocannabinoid system, and in particular the CB₁ R, plays a pivotal role in the long-lasting and incremental reversal of hyperalgesia induced by repetitive SCS in a neuropathic pain model.

SIGNIFICANCE

Alternative parameters for repetitive spinal cord stimulation (SCS) at 25/10 Hz elicit particularly long-lasting and incremental reversal of hyperalgesia in a neuropathic pain model through a mechanism involving endocannabinoids.

[Security analysis of implanting drug-eluting stents for unprotected left main coronary artery disease patients with chronic kidney disease]

OBJECTIVE

To study the clinical characteristics and prognosis of unprotected left main (ULM) coronary artery disease patients with chronic kidney disease after drug-eluting stents (DES) implantation.

METHODS

267 ULM coronary artery disease patients who has implanted DES were included in the study from January 2005 to March 2010. Patients were divided into two groups according to their estimated glomerular filtration rate (eGFR): eGFR <60 ml·min(-1)·1.73 m(-2) (77 patients), and eGFR≥ 60 ml·min(-1)·1.73 m(-2) (190 patients) . The clinical parameters and prognosis of ULM patients treated with DES in different eGFR groups were retrospectively compared.

RESULTS

In higher eGFR group, left ventricular ejection fraction (LVEF) and morbidity of coronary ostial lesions were higher than the other group. Cerebrovascular diseases (13.0% vs 5.3%), chronic total occlusion (CTO, 28.6% vs 12.1%), hypertension (70.1% vs 53.2%) were more common in lower eGFR patients(all P<0.05). Total mortality and cardiac mortality were higher in eGFR<60 ml·min(-1)·1.73 m(-2) group (P=0.016, 0.006, respectively). Low eGFR level was an independent risk factor after adjusting multiple factors.

CONCLUSION

For the ULM disease patients with reduction in kidney function (eGFR<60 ml·min(-1)·1.73 m(-2)), DES should be selected with a careful study considering its increasing risk of death. Chronic renal insufficiency is a risk factor and may predict poor prognosis for patients with ULM after DES implantation.

A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep

To study metabolic adaptation to harsh foraging conditions, an experiment was conducted to characterize and quantify N utilization efficiency and urea metabolism in Tibetan and fine-wool sheep fed 4 levels of dietary N (11.0, 16.7, 23.1, and 29.2 g N/kg DM) in 2 concurrent 4 × 4 Latin square designs. Urea kinetics were determined using continuous intrajugular infusions of 15N15N-urea. Urinary excretions of total N and urea N increased linearly (P < 0.001) with dietary N and were not different between breeds (P ≥ 0.37). Fecal N excretion increased with dietary N for Tibetan sheep but not for fine-wool sheep (linear dietary N × breed; P < 0.05). Nitrogen retention (both amount per day and percentage of N intake) increased with increasing dietary N concentration (P < 0.001), and the rates of increase were greater in fine-wool than in Tibetan sheep (linear dietary N × breed and cubic dietary N × breed; P < 0.05). In Tibetan sheep, N retention as a percentage of intake was greatest for diets containing 16.7 g N/kg DM, whereas it was maximal for fine-wool sheep when the diet contained 23.1 g N/kg DM. Urea N entry rate, urea N recycled to the gastrointestinal tract (GIT), and urea N returned to the ornithine cycle all increased with dietary N (P < 0.05), and all were greater in Tibetan than fine-wool sheep for the 11.0 g N/kg DM diet but were greater in fine-wool than Tibetan sheep for the diet with 29.2 g N/kg DM (linear dietary N × breed; P < 0.05). Urea N excreted in feces, both amount and fraction of GIT entry rate, was less in Tibetan than fine-wool sheep for the 11.0 and 16.7 g N/kg DM diets but similar for diets with 23.1 or 29.2 g N/kg DM (linear dietary N × breed; P < 0.01). For the lowest-protein diet, the fraction of urea N production recycled to the GIT was greater in the Tibetan than fine-wool sheep (88% vs. 82%), but for the diet with 29.2 g N/kg DM it was greater for fine-wool than Tibetan sheep (46% vs. 39%; linear dietary N × breed; P < 0.05). Plasma urea N increased more rapidly in response to increasing dietary N concentration for fine-wool sheep than for Tibetan sheep (linear dietary N × breed; P < 0.05). Urea tubular load and the amount and percentage of urea reabsorbed by the kidney were greater in Tibetan than fine-wool sheep (P < 0.05). These results suggest that Tibetan sheep have mechanisms that allow them to utilize N more efficiently than the fine-wool sheep when dietary N is inadequate.

Influence of wavefront aberration on the imaging performance of the solar grating spectrometer

The solar grating spectrometer is an important tool to study the thermodynamic properties of the solar atmosphere with different height distribution, but its imaging performance will be degraded by the wavefront aberration. On the other hand, narrow slit of the grating spectrometer will filter the wavefront aberration to a certain extent. In this paper, the mathematical relation between the wavefront aberration and the imaging performance of the grating spectrometer is derived. The numerical simulation is performed and is validated by the experiment. The results demonstrate that: The influence of the wavefront aberration with the different types and magnitudes on the spectral resolution and the energy utilization is different. The influence of the different slits on the wavefront aberrations is different. Generally, the smaller the slit is, the better the spectral resolution is. However, this is not true for the low-frequency dominated aberration, e.g. the defocus, since its low frequency will also be blocked by the narrow slit. If the influence of the filter slit on the wavefront aberration cannot be taken into account, it will lead to adaptive optics over-compensation.

Different gene expressions between cattle and yak provide insights into high-altitude adaptation

DNA sequence variation has been widely reported as the genetic basis for adaptation, in both humans and other animals, to the hypoxic environment experienced at high altitudes. However, little is known about the patterns of gene expression underlying such hypoxic adaptations. In this study, we examined the differences in the transcriptomes of four organs (heart, kidney, liver and lung) between yak and cattle, a pair of closely related species distributed at high and low altitudes respectively. Of the four organs examined, heart shows the greatest differentiation between the two species in terms of gene expression profiles. Detailed analyses demonstrated that some genes associated with the oxygen supply system and the defense systems that respond to threats of hypoxia are differentially expressed. In addition, genes with significantly differentiated patterns of expression in all organs exhibited an unexpected uniformity of regulation along with an elevated frequency of nonsynonymous substitutions. This co-evolution of protein sequences and gene expression patterns is likely to be correlated with the optimization of the yak metabolic system to resist hypoxia.

Hepatoprotective effects of selenium during diabetes in rats

The present study investigated the hepatoprotective role of selenium during alloxan-induced diabetes in rats. Male Wistar rats were divided into four groups, namely, normal control, selenium treated, diabetic, and selenium-treated diabetic. Diabetes was induced in the animals by injecting alloxan intraperitoneally at a dose rate of 150 mg/kg body weight. Selenium in the form of sodium selenite was supplemented to rats at a dose level of 1 ppm in drinking water, ad libitum for two time durations of 2 and 4 weeks. The effects of different treatments were studied on various parameters in rat liver, which included serum glucose levels, serum insulin levels, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lipid peroxidation (LPO), glutathione reduced (GSH), oxidized glutathione (GSSG), total glutathione (TG), superoxide dismutase (SOD), catalase (CAT), glutathione reductase, glutathione peroxidase, metallothionein (MT), and histoarchitecture. A significant increase in the serum glucose levels, LPO levels, and in enzyme activities of ALP, ALT, and AST was observed in diabetic rats which, however, got decreased significantly upon supplementation with selenium. On the contrary, decreased enzyme activities of GSSG, SOD, and CAT and depressed levels of GSH as well as serum insulin levels were observed in diabetic rats which got improved following selenium supplementation. Interestingly, MT levels were increased both in diabetic and selenium-treated diabetic rats. Further, marked alterations in histoarchitecture were seen in diabetic rats with the prominent features being congestion in sinusoids, lipid accumulation, and centrilobular hepatocyte degeneration. However, selenium treatment to diabetic rats showed overall improvement in the hepatic histoarchitecture.

Movement rehabilitation in virtual reality from then to now: how are we doing?

During the past decade, there has been a continuous exploration of how virtual environments can be used to facilitate motor recovery and relearning after neurological impairment. There are two goals for using virtual environments: to improve patients' rehabilitation outcomes beyond our current capabilities or to supplement labor-intensive and time consuming therapies with technology-based interventions. After over a decade of investigation, it seems appropriate to determine whether we are succeeding in meeting such goals.