Protection of Icariin Against Hydrogen Peroxide‐Induced MC3T3‐E1 Cell Oxidative Damage

ObjectiveThe aim of the present study was to evaluate the potential protective mechanism of icariin against oxidative damage caused by hydrogen peroxide in MC3T3‐E1 cells.MethodsMC3T3‐E1 cells were treated with different concentrations of icariin to explore the optimal dose of icariin. MC3T3‐E1 cells were divided into groups treated with various concentrations of hydrogen peroxide (H₂O₂; 0, 0.1, 0.2, 0.5, 1, and 2 mM) for 24 h to induce oxidative damage and cell viability was assessed by Cell Counting Kit‐8 (CCK‐8) assay. Then, cells were divided into five groups: control, H₂O₂ (0.2 mM), icariin (0.1 μM) and H₂O₂ (0.2 mM), + icariin (0.1 μM). Cell viability was detected by CCK‐8 assay. In addition, the content of glutathione and superoxide dismutase and the activity level of malondialdehyde in these treatment groups were determined. Alkaline phosphatase (ALP) and alizarin red S (ARS) staining were also performed to measure the early and late osteogenesis, respectively. Protein expression of β‐catenin and cyclin D1 was measured by western blot assay. Then, we used an antagonist of Wnt/β‐catenin signaling pathway (DKK‐1) and western blot analysis to further explore potential mechanism.ResultsAfter 24 h of exposure to 0.2 mM H₂O₂, the viability of MC3T3‐E1 cells was significantly decreased compared to that of the control cells. We first found that icariin can promote cell proliferation of MC3T3‐E1 cells in a dose‐dependent manner, with the dosage 0.1 μM showing the best pro‐proliferative effect. Furthermore, icariin could promote the protein expression of OSX and RUNX2. The results showed that icariin can reverse the inhibitory osteogenic effects of MC3T3‐E1 caused by H₂O₂. In addition, icariin could increase the Wnt‐signaling related proteins. The results showed that MC3T3‐E1 cells in the H₂O₂ (0.2 mM) + icariin (0.1 μM) + Wnt‐signaling antagonist (DKK‐1) group had weaker ALP and ARS staining compared with that observed in the control and H₂O₂ (0.2 mM) + icariin (0.1 μM) groups. The ALP activity and calcium content were decreased in the 0.2 mM H₂O₂ + 0.1 μM icariin + DKK‐1 group compared to that observed in the 0.2 mM H₂O₂ + 0.1 μM icariin group.ConclusionThe results showed that icariin can increase the viability of MC3T3‐E1 cells, reverse the oxidative stress induced by H₂O₂ and protect MC3T3‐E1 cells against H₂O₂‐induced inhibition of osteogenic differentiation, which may occur through the Wnt/β‐catenin signaling pathway.     

Effect of vildagliptin as add-on therapy to a low-dose metformin

AIM: To evaluate the efficacy and safety of the addition of vildagliptin to low-dose metformin and compare it to an uptitration of metformin in type 2 diabetes mellitus (T2DM) patients who have inadequate control with metformin monotherapy.METHODS: Eligible patients were randomized to receive vildagliptin 100 mg qd or metformin (500 mg qd for 2 wk and then 500 mg bid) added to open label metformin 500 mg bid for the 24 wk. The primary endpoint was baseline to endpoint hemoglobin A_1c (HbA_1c) change.RESULTS: The adjusted mean change from baseline in HbA_1c at the 24th wk was -0.51% in the vildagliptin/metformin group (mean baseline HbA_1c: 7.4%) and -0.37% in the metformin monotherapy group (mean baseline HbA_1c: 7.3%). The mean difference was -0.14% with 95% Confidence Interval (-0.24%, -0.05%). As non-inferiority (margin of 0.4%) was achieved, a test for superiority was performed. This test showed statistically significant superiority of the combination over monotherapy group (P = 0.002). Gastrointestinal (GI) adverse events were significantly more frequent in the metformin group than the combination group (21.0% vs 15.4%, P = 0.032).CONCLUSION: In patients with T2DM inadequately controlled with metformin up to 1000 mg daily, the addition of vildagliptin 100 mg daily achieved larger HbA_1c reduction with fewer GI events than with increasing the metformin dose.     

Tamsulosin alters levofloxacin pharmacokinetics in prostates derived from rats with acute bacterial prostatitis

The combination of levofloxacin and α₁ adrenergic antagonist treatment is the current preferred choice for both bacterial and non-bacterial prostatitis. The aim of this study is to explore the influence of α₁ adrenergic antagonists on the pharmacokinetics of levofloxacin using rat models with acute bacterial prostatitis (ABP) induced by direct injection with Escherichia coli (ATCC25922). A total of 96 model rats were randomly assigned into two groups: the experimental group (treated with both tamsulosin and levofloxacin, n=48) and the control group (treated with levofloxacin and solvents, n=48). Six rats from each group were euthanized to collect blood, liver, kidney and prostate samples at the time points of 0.125, 0.25, 0.5, 1, 2, 4, 8 and 12 h after drug administration. The levofloxacin concentrations were detected by high performance liquid chromatography (HPLC), and the pharmacokinetic parameters were calculated using the 3p97 software program. There were no obvious differences (P>0.05) between the experimental and control groups in the major pharmacokinetic parameters of levofloxacin, including the halftime (t_1/2), time to peak (t_peak), clearance rate (CL), maximum concentration (C_max) and area under the curve (AUC_0∼12), in the plasma or in the hepatic and kidney tissues of the model rats. However, in the prostatic tissues, tamsulosin increased the C_max, prolonged the t_1/2 and decreased the CL of levofloxacin (P<0.05). These results indicate that tamsulosin may enhance the effect of levofloxacin in the treatment of bacterial prostatitis without changing the drug concentration in the liver and kidney.     

Fibronectin fragments active in chondrocytic chondrolysis can be chemically cross-linked to the alpha5 integrin receptor subunit

OBJECTIVE: To determine whether fibronectin fragments (Fn-f) known to enhance cartilage matrix degradation and to alter chondrocyte metabolism, bind on the chondrocyte cell surface close enough to the alpha(5)beta(1) fibronectin (Fn) receptor to be chemically cross-linked to it. DESIGN: Biotinylated Fn-fs were added to chondrocytes, followed by cross-linking with dithiobissulfosuccinimidyl propionate, and the resultant alpha(5) complexes trapped on to antialpha(5)-agarose. Adherent material was analysed by probing with avidin-HRP. In a more specific approach in which only proximal targets could be cross-linked, photoaffinity labeled Fn-fs or Fn were added to cells, the derivatives activated and the cross-linked material analysed. Interaction of biotinylated Fn-fs and Fn with insolubilized alpha(5)beta(1) receptor was also visualized and quantified. RESULTS: Biotinylated Fn-fs and Fn, but not a control of BSA, were cross-linked to alpha(5) protein in the presence of the propionate. Photoaffinity label Fn-f and Fn, but not BSA, were cross-linked to alpha(5) protein as well. Interaction was decreased by addition of an excess of unlabeled Fn-f or Fn. Fn-fs bound to alpha(5)beta(1)-agarose, although the affinity was 30-fold weaker and the stoichiometry 20-fold greater when the smallest Fn-f was compared to native Fn. CONCLUSIONS: These data are consistent with a role for the alpha(5) subunit in Fn-f activities and suggest that the Fn-fs bind proximal or directly to alpha(5) receptors. The weaker, higher stoichiometry interaction of Fn-fs with receptor suggests that fragmentation has allowed de novo interactions not possible in native Fn.     

Biomechanical Effects of Lateral Inclination C1 and C2 Pedicle Screws on Atlantoaxial Fixation

ObjectiveTo assess the biomechanical effect of lateral inclination C₁ and C₂ pedicle screws on the atlantoaxial fixation through vitro human cadaveric study.MethodsFrom January 2016 to December 2017, fresh‐frozen cadaveric cervical spines with intact ligaments from eight donated cadavers at an average age of 71.5 ± 10.6 years, comprising of six males and two females, were collected. There were no fracture and congenital malformation in all specimens according to the imaging examination. The range of motion (ROM) of the specimens were tested in their intact condition and destabilized condition. Next, the specimens were randomly divided into two groups to ensure no differences in sex and age: Group 1 was medial inclination C₁ pedicle screw and C₂ pedicle screws (C₁MPS‐C₂PS) and Group 2 was lateral inclination C₁ pedicle screw and C₂ pedicle screws (C₁LPS‐C₂PS). The ROM of the fixation scenarios were recorded. Thereafter, all the specimens with fixation constructs were tested for 1,000 cycles of axial rotation and tensile loading to failure was carried out collinearly to the longitudinal axis of all the screws, the data were documented as screw pullout strength (SPS) in newtons. All the recorded data subjected to quantitative analysis.ResultsThe ROM of specimens was increased significantly in destabilized condition and significantly reduced in fixation condition compared with intact condition. In C₁LPS‐C₂PS groups, the C₁‐C₂ cervical segment showed 3.96° ±1.21° and 3.75° ± 1.33° in flexion and extension direction, 2.85° ± 0.91° and 2.96° ± 0.71° in right and left lateral bending, 2.20° ± 0.43° and 2.15° ± 0.40° in right and left axial rotation. In C₁MPS‐C₂PS groups, it showed 4.24° ±1.31° and 3.98° ± 1.21° in flexion and extension direction, 2.76° ± 1.10° and 3.23° ± 0.62° in right and left lateral bending, 2.20° ± 0.46° and 2.21° ± 0.42° in right and left axial rotation. There was no statistically significant difference on ROM and screw pullout strengths (764.29 ± 129.00 N vs 714.55 ± 164.63 N) between the two groups. However, there was one specimen in the C₁MPS‐C₂PS group showing rupture the inferior wall of the left screw trajectory owing to the relatively thin posterior arch of the atlas, the screw pullout strength was significantly reduced (left pullout strength value: 430.5 N, right pullout strength value: 748.4 N). Therefore, in the case of the thin posterior arch of the atlas, the C₁LPS‐C₂PS group had strong long‐term biomechanics.ConclusionThe lateral inclination C₁ pedicle screw can achieve the same biomechanical strength as the traditional atlas pedicle screw. However, for the case where the posterior arch of the atlas is relatively thin, a lateral inclination C₁ pedicle screw is more suitable.     

Posterior projecting carotid-A<Subscript>1</Subscript> junctional aneurysms

Summary The authors report on two types of carotid-A₁ junctional aneurysms projecting backwards. In the two A₁-type examples, the aneurysm originated at the posterior wall of the proximal A₁ joining the carotid termination and could be clipped using an ipsilateral pterional approach. However, in the carotid-type example, the aneurysm originated at the posterior wall of the carotid termination just below the A₁ origin, and required a contralateral pterional approach to expose the aneurysm. Although the carotid-A₁ junctional aneurysms are rare, their exact location and size can affect the side of the operative approach.     

Differential expression of adenosine A1 and A2A receptors after upper cervical (C2) spinal cord hemisection in adult rats

BACKGROUND: In an animal model of spinal cord injury, a latent respiratory motor pathway can be pharmacologically activated via adenosine receptors to restore respiratory function after cervical (C2) spinal cord hemisection that paralyzes the hemidiaphragm ipsilateral to injury. Although spinal phrenic motoneurons immunopositive for adenosine receptors have been demonstrated (C3-C5), it is unclear if adenosine receptor protein levels are altered after C2 hemisection and theophylline administration. OBJECTIVE: To assess the effects of C2 spinal cord hemisection and theophylline administration on the expression of adenosine receptor proteins. METHODS: Adenosine A1 and A2A receptor protein levels were assessed in adult rats classified as (a) noninjured and theophylline treated, (b) C2 hemisected, (c) C2 hemisected and administered theophylline orally (3x daily) for 3 days only, and (d) C2 hemisected and administered theophylline (3x daily for 3 days) and assessed 12 days after drug administration. Assessment of A1 protein levels was carried out via immunohistochemistry and A2A protein levels by densitometry. RESULTS: Adenosine A1 protein levels decreased significantly (both ipsilateral and contralateral to injury) after C2 hemisection; however, the decrease was attenuated in hemisected and theophylline-treated animals. Attenuation in adenosine A1 receptor protein levels persisted when theophylline administration was stopped for 12 days prior to assessment. Adenosine A2A protein levels were unchanged by C2 hemisection; however, theophylline reduced the levels within the phrenic motoneurons. Furthermore, the decrease in A2A levels persisted 12 days after theophylline was withdrawn. CONCLUSION: Our findings suggest that theophylline mitigates the effects of C2 hemisection by attenuating the C2 hemisection-induced decrease in A1 protein levels. Furthermore, A2A protein levels are unaltered by C2 hemisection but decrease after continuous or interrupted theophylline administration. The effects on protein levels may underlie the stimulant actions of theophylline.     

A Comparison of Intravenous Sedation With Two Doses of Dexmedetomidine: 0.2?μg/kg/hr Versus 0.4?μg/kg/hr

The present study investigated the physiologic and sedative effects between two different continuous infusion doses of dexmedetomidine (DEX). Thirteen subjects were separately sedated with DEX at a continuous infusion dose of 0.2 µg/kg/hr for 25 minutes after a loading dose of 6 µg/kg/hr for 5 minutes (0.2 group) and a continuous infusion dose of 0.4 µg/kg/hr for 25 minutes after a loading dose of 6 µg/kg/hr for 5 minutes (0.4 group). The recovery process was then observed for 60 minutes post infusion. The tidal volume, mean arterial pressure, and heart rate in both groups decreased significantly during infusion, but they were within a clinically acceptable level. A Trieger dot test plot error ratio in the 0.4 group was significantly higher than that in the 0.2 group until 15 minutes post infusion. Sedation appears to be safe at the infusion doses of DEX studied. However, increasing maintenance infusion doses of DEX from 0.2 µg/kg/hr to 0.4 µg/kg/hr delays some recovery parameters.     

Intravenous sedation with low-dose dexmedetomidine: its potential for use in dentistry

This study investigated the physiologic and sedative parameters associated with a low-dose infusion of dexmedetomidine (Dex). Thirteen healthy volunteers were sedated with Dex at a loading dose of 6 mcg/kg/h for 5 minutes and a continuous infusion dose of 0.2 mcg/kg/h for 25 minutes. The recovery process was observed for 60 minutes post infusion. The tidal volume decreased significantly despite nonsignificant changes in respiratory rate, minute ventilation, oxygen saturation, and end-tidal carbon dioxide. The mean arterial pressure and heart rate also decreased significantly but within clinically acceptable levels. Amnesia to pin prick was present in 69% of subjects. A Trieger dot test plot error ratio did not show a significant change at 30 minutes post infusion despite a continued significant decrease in bispectral index. We conclude that sedation with a low dose of Dex appears to be safe and potentially efficacious for young healthy patients undergoing dental procedures.     

Role of P2X_7 receptors in the development of diabetic retinopathy

The P2X7 receptor is one of the members of the family of purinoceptors which are ligand-gated membrane ion channels activated by extracellular adenosine 5'-triphosphate. A unique feature of the P2X7 receptor is that its activation can result in the formation of large plasma membrane pores that allow not only the flux of ions but also of hydrophilic molecules of up to 900 Da. Recent studies indicate that P2X7-mediated signaling can trigger apoptotic cell death after ischemia and during the course of certain neurodegenerative disorders. Expression of the P2X7 receptor has been demonstrated in most types of cells in the retina. This purinoceptor mediates the contraction of pericytes and regulates the spatial and temporal dynamics of the vasomotor response through cell-to-cell electrotonic transmission within the microvascular networks. Of potential clinical significance, investigators have found that diabetes markedly boosts the vulnerability of retinal microvessels to the lethal effect of P2X7 receptor activation. This purinergic vasotoxicity may result in reduced retinal blood flow and disrupted vascular function in the diabetic retina. With recent reports indicating an association between P2X7 receptor activation and inflammatory cytokine expression in the retina, this receptor may also exacerbate the development of diabetic retinopathy by a mechanism involving inflammation.     

Mechanism of sperm capacitation and the acrosome reaction: role of protein kinases

Mammalian sperm must undergo a series of biochemical and physiological modifications, collectively called capacitation, in the female reproductive tract prior to the acrosome reaction (AR). The mechanisms of these modifications are not well characterized though protein kinases were shown to be involved in the regulation of intracellular Ca²⁺ during both capacitation and the AR. In the present review, we summarize some of the signaling events that are involved in capacitation. During the capacitation process, phosphatidyl-inositol-3-kinase (PI3K) is phosphorylated/activated via a protein kinase A (PKA)-dependent cascade, and downregulated by protein kinase C α (PKCα). PKCα is active at the beginning of capacitation, resulting in PI3K inactivation. During capacitation, PKCα as well as PP1γ2 is degraded by a PKA-dependent mechanism, allowing the activation of PI3K. The activation of PKA during capacitation depends mainly on cyclic adenosine monophosphate (cAMP) produced by the bicarbonate-dependent soluble adenylyl cyclase. This activation of PKA leads to an increase in actin polymerization, an essential process for the development of hyperactivated motility, which is necessary for successful fertilization. Actin polymerization is mediated by PIP₂ in two ways: first, PIP₂ acts as a cofactor for phospholipase D (PLD) activation, and second, as a molecule that binds and inhibits actin-severing proteins such as gelsolin. Tyrosine phosphorylation of gelsolin during capacitation by Src family kinase (SFK) is also important for its inactivation. Prior to the AR, gelsolin is released from PIP₂ and undergoes dephosphorylation/activation, resulting in fast F-actin depolymerization, leading to the AR.     

Effect of prostaglandin E1 on preservation injury of canine liver grafts preserved in UW solution

This study investigated whether prostaglandin E₁ (PGE₁) could reduce hepatic injury to the liver graft caused by harvesting and 24-h preservation in University of Wisconsin (UW) solution in a canine model. The PGE₁-treated group was intravenously administered 0.5 g/kg per minute of PGE₁ for 30 min before harvesting, as well as a concentration of 1 mg/l PGE₁ in the washout and UW solutions. In both the PGE₁-treated and the control group, all recipients survived for 1 week or more after transplantation. Arterial ketone body ratio (AKBR) remained over 1.0 in the early postoperative period. The PGE₁ group showed significant reductions in guanase, GOT, and LDH during the early postoperative period compared to the untreated control group. Histological examination disclosed partial mitochondrial swelling, hepatocyte vacuolation, and necrosis in the control group, while such abnormalities were rarely seen in the PGE₁ group. These results suggest that PGE₁ can effectively reduce hepatic injury to liver grafts preserved in UW solution prior to transplantation.     

Evaluation of Serum 25‐Hydroxyvitamin D3 and Bone Mineral Density in 268 Patients with Hip Fractures

ObjectiveThe aim of the present study was to evaluate the relationship among vitamin D nutritional status, bone mineral density, and other factors in elderly patients with brittle hip fractures.MethodsThe present study was a retrospective analysis of 268 patients, 102 men (38.06%) and 166 women (61.94%), with brittle hip fractures admitted to the Hip Joint Center of Tianjin Hospital from February 2016 to June 2018. The median age of the patients was 74 years (range, 50–93 years). The patients were divided into three groups based on age: ≤69 years, 70–79 years, and ≥80 years. Serum 25‐hydroxyvitamin D₃ (25(OH) D₃), parathyroid hormone (PTH), body mass index (BMI), and bone mineral density (BMD) of the lumbar spine, femoral neck, and hip were measured and statistically analyzed.ResultsThe median serum 25(OH)D₃ level of patients was 9.90 (range, 2.60–42.70) ng/mL; the proportion of deficiency was 89.18% and the deficiency was severe in 136 cases (49.25%). The proportion of vitamin D deficiency was significantly lower in men than in women (P = 0.013). With the increase of age, 25(OH)D₃ levels gradually decreased (P = 0.044) and PTH levels gradually increased (P < 0.001). There was significantly negative correlation (P < 0.001) between the levels of serum 25(OH)D₃ and PTH. There were 200 cases (74.63%) in which T‐values of BMD were less than −2.5 in any part of the lumbar vertebrae, femoral neck, and hip. T‐values in 74 cases (27.61%) were less than −2.5 in all three parts. The T‐values of BMD in men were significantly higher than those in men (P < 0.001). With the increase of age, the femoral neck BMD in men gradually decreased (P = 0.016), and the femoral neck and hip BMD in female gradually decreased (P‐value was 0.001 and 0.003, respectively). Multivariate analysis suggested that gender and BMI were independent risk factors for BMD, and vitamin D deficiency affected BMD.ConclusionVitamin D deficiency is common in patients with brittle hip fractures, especially in women. With the increase of age, vitamin D continues to decrease and PTH increases. The decrease of BMD in patients with hip fractures is the result of a combination of age, gender, BMI, and vitamin D content.