Cannabinoid receptor down-regulation without alteration of the inhibitory effect of CP 55,940 on adenylyl cyclase in the cerebellum of CP 55,940-tolerant mice

The objective of this study was to determine whether the development of tolerance to CP 55,940, a potent cannabinoid agonist, was due to changes in the receptor or second messenger system. ICR mice treated with CP 55,940 (2 mg/kg) twice a day for 6 and one-half days developed a high degree of tolerance to the pharmacological effects of CP 55,940. The ability of CP 55,940 to produce motor hypoactivity, hypothermia and immobility was reduced 163-, 97- and 19-fold, respectively. Evaluation of 3H-CP 55,940 binding to rat brain membranes indicated no difference in receptor affinity between the vehicle- and CP 55,940-treated animals. However, these binding studies revealed a 50% decrease in receptor number in the cerebellum of the CP 55,940-tolerant mice. Although cAMP is generally considered to be the second messenger for cannabinoid receptors, little difference was observed in the inhibitory effects of CP 55,940 on adenylyl cyclase activity in cerebellum between vehicle and drug-treated mice. However, there was an increase in receptor mRNA which suggests a compensation for receptor loss. There are several possible explanations for these results. There may be sufficient spare receptors such that CP 55,940-tolerant mice are capable of producing a maximal effect on the second messenger system. On the other hand, one could conclude that cannabinoid receptor down-regulation does not account for the development of tolerance to all of the effects of CP 55,940 in mice.     

Influence of Various Immunomodulators on the Induction of Experimental Autoimmune Encephalomyelitis in Lewis Rats

The effect of various immunomodulators on the induction of experimental autoimmune encephalomyelitis (EAE) is evaluated in the Lewis rat. Bordetella pertussis (BP) is the optimal inductor of EAE in this rat strain. Treatment of the animals with BP either before or after or simultaneously with guinea-pig spinal cord preparation (GpSC) resulted in an EAE about two weeks thereafter. Additional injection of living BCG, of CFA, IFA (incomplete Freund's adjuvant) or Vibrio cholerae neuraminidase (VCN) did not augment or mitigate the effect induced by BP or GpSC. Living BCG, IFA, VCN or Corynebacterium parvum (CP) did not induce EAE when given in combination with GpSC but without BP. CFA combined with GpSC only occasionally induced EAE. However, EAE could be induced by the combination of CFA and GpSC or IFA and GpSC in a part of the animals tested if they had been pretreated or simultaneously been injected with living BCG by intravenous route. EAE could not be enhanced by the additional injection of VCN. Surprisingly, most of the animals peracutely died after injection of CFA and BP in combination with GpSC when they had been pretreated with CP. This effect was most pronounced when pretreatment was done on day -4. No acute effect could be seen when CP was given simultaneously to CFA, BP and GpSC. Animals which did not peracutely succumb developed EAE similarly as those in the positive control groups. CP treatment simultaneously with BP but without CFA resulted in a reduction of the EAE specific mortality. This reduction could not be seen if treatment with CP was done after injection of GpSC and BP.     

Genotoxicity studies of glycidol fatty acid ester (glycidol linoleate) and glycidol

Glycidol fatty acid esters (GEs) are found in refined edible oils. Safety concerns have been alleged due to the possible release of glycidol (G), an animal carcinogen.     

Different strategies of mixed chimerism induction may determine stem/progenitor cell populations in recipient mice

Mixed chimerism has been suggested to induce tolerance to transplanted alloantigens. As the precise influence of mixed chimerism induction on the host organism has still not been fully elucidated, the aim of the present study was to explore this phenomenon in relation to the stem cell compartment.The experiment was performed on B6.SJL-Ptprc^aPep3^b mice. Mixed chimerism induction protocols involved 3 Gy TBI (Day − 1 of the experiment), injection of 20-30 × 10⁶ Balb C bone marrow cells (Day 0), and administration of blocking antibodies against CD40L (Day 0 and Day 4), anti-CD8 (Day − 2) with/without anti-NK1.1 (Day − 3). Selected groups of mice were also treated with cyclophosphamid (175 mg/kg) on Day 2. The presence of mixed chimerism was assessed in peripheral blood, bone marrow, and spleen, as well as in various subpopulations of leukocytes (CD4⁺, CD8⁺, CD45/B220⁺, Gr-1⁺, lin⁻/Sca-1⁺/c-kit⁻, lin⁻/Sca-1⁺/c-kit⁺, lin⁻/Sca-1⁻/c-kit⁺). Furthermore, the percentage of stem/progenitor cells (lin⁻/Sca-1⁺/c-kit⁻, lin⁻/Sca-1⁺/c-kit⁺, lin⁻/Sca-1⁻/c-kit⁺, VSEL, HSC) was analysed for the first time in bone marrow and peripheral blood of chimeric mice.The range of mixed chimerism differed significantly among various cell populations: it was lowest in CD8-positive cells and lin⁻/Sca-1⁺/c-kit⁻ cells, and highest in granulocytes. The induction of mixed chimerism revealed a significant impact on the stem/progenitor cell frequency in recipient mice, providing potential therapeutic insights into the long-term immunologic tolerance observed in chimeric mice. Collectively, these findings contribute to further optimization of mixed chimerism induction protocols and might help in the introduction of this phenomenon into clinical practice.     

内固定治疗肱骨近端骨折(Neer 3型)的生物力学研究

目的通过生物力学研究,对比三种治疗肱骨近端骨折(Neer 3型)内固定结构的稳定性及耐久性。方法按照统一标准制作肱骨近端3部分外科颈大结节骨折模型,分别予空心钉、克氏针及三叶草钢板固定。所有标本进行循环外展实验、循环屈伸实验及压扭负载。结果加压空心钉的结构稳定性较克氏针好而次于三叶草钢板。空心钉及克氏针内固定结构稳定性与骨密度(BMD)有很大的相关性。结论加压空心钉治疗肱骨近端骨折是一种微创的内固定手术,手术时间短,能满足内固定的要求,提供术后患者进行功能锻炼的结构稳定性,是一种治疗老年肱骨近端骨折的可靠方法。     

经尿道前列腺等离子电切术联合药物对BPH合并CP的疗效

目的探讨经尿道前列腺等离子电切术(PKRP)联合药物治疗对良性前列腺增生(BPH)并慢性前列腺炎(CP)的临床疗效。方法选取2013年6月~2014年6月于我院接受治疗的60例BPH合并CP患者作为研究对象,所有患者均使用经尿道前列腺等离子电切术联合α-受体阻滞剂进行治疗,观察患者术前、术后各观察指标变化情况。结果 60例患者平均手术时间(52.4±10.8)min,平均出血量和平均住院时间分别为(74.7±20.5)ml、(6.0±3.1)d,患者术后并无尿道穿孔、外渗、尿失禁等并发症。随访3个月,患者的IPSS、QOL、RUV各个评分低于治疗前,Qmax评分高于治疗前,P0.05,差异具有统计学意义。结论经尿道前列腺等离子电切术(PKRP)联合药物治疗BPH合并CP患者,具有操作简单、安全等特点,能有效缓解患者排尿困难、尿路梗阻的问题,改善其生活质量。     

Adenosine A2A receptors and brain injury: broad spectrum of neuroprotection, multifaceted actions and "fine tuning" modulation

This review summarizes recent developments that have contributed to understand how adenosine receptors, particularly A2A receptors, modulate brain injury in various animal models of neurological disorders, including Parkinson's disease (PD), stroke, Huntington's disease (HD), multiple sclerosis, Alzheimer's disease (AD) and HIV-associated dementia. It is clear that extracellular adenosine acting at adenosine receptors influences the functional outcome in a broad spectrum of brain injuries, indicating that A2A Rs may modulate some general cellular processes to affect neuronal cells death. Pharmacological, neurochemical and molecular/genetic approaches to the complex actions of A2A receptors in different cellular elements suggest that A2A receptor activation can be detrimental or protective after brain insults, depending on the nature of brain injury and associated pathological conditions. An interesting concept that emerges from these studies is A2A R's ability to fine tune neuronal and glial functions to produce neuroprotective effects. While the data presented here clearly highlight the complexity of using adenosinergic agents therapeutically in PD and other neurodegenerative disorders and point out many areas for further inquiry, they also confirm that adenosine receptor ligands, particularly A2A receptor ligands, have many promising characteristics that encourage the pursuit of their therapeutic potential.     

Approaches and considerations for the assessment of immunotoxicity for environmental chemicals: A workshop summary

As experience is gained with toxicology testing and as new assays and technologies are developed, it is critical for stakeholders to discuss opportunities to advance our overall testing strategies. To facilitate these discussions, a workshop on practices for assessing immunotoxicity for environmental chemicals was held with the goal of sharing perspectives on immunotoxicity testing strategies and experiences, developmental immunotoxicity (DIT), and integrated and alternative approaches to immunotoxicity testing. Experiences across the chemical and pharmaceutical industries suggested that standard toxicity studies, combined with triggered-based testing approaches, represent an effective and efficient approach to evaluate immunotoxic potential. Additionally, discussions on study design, critical windows, and new guideline approaches and experiences identified important factors to consider before initiating DIT evaluations including assay choice and timing and the impact of existing adult data. Participants agreed that integrating endpoints into standard repeat-dose studies should be considered for fulfilling any immunotoxicity testing requirements, while also maximizing information and reducing animal use. Participants also acknowledged that in vitro evaluation of immunosuppression is complex and may require the use of multiple assays that are still being developed. These workshop discussions should contribute to developing an effective but more resource and animal efficient approach for evaluating chemical immunotoxicity.     

Plasma-derived mannose-binding lectin shows a direct interaction with C1-inhibitor

MBL-deficiency has been associated with an increased frequency and severity of infection, in particular in children and under immunocompromized conditions. In an open uncontrolled safety and pharmacokinetic MBL-substitution study using plasma-derived MBL (pdMBL) in MBL-deficient pediatric oncology patients, we found that despite MBL trough levels above 1.0 μg/ml MBL functionality was not efficiently restored upon ex vivo testing.