Behavioral evaluation of rats following low-level inhalation exposure to sarin

We evaluated the effects, in rats, of single and multiple low-level inhalation exposures to sarin. Rats were trained on a variable-interval, 56 s (VI56) schedule of food reinforcement and then exposed to sarin vapor (1.7-4.0 mg/m(3) x 60 min) or air control. The exposures did not produce clinical signs of toxicity other than miosis. Subsequently, performance on the VI56 and acquisition of a radial-arm maze spatial memory task was evaluated over approximately 11 weeks. Single exposures did not affect performance on the VI56 and had little effect on acquisition of the radial-arm maze task. Multiple exposures (4.0 mg/m(3) x 60 min/day x 3) disrupted performance on the VI56 schedule during the initial post-exposure sessions. The disruption, however, resolved after several days. Multiple exposures also produced a deficit on the radial-arm maze task in that sarin-exposed rats tended to take it longer to complete the maze and to make more errors. The deficit, however, resolved during the first three weeks of acquisition. These results demonstrate that in rats, inhalation exposure to sarin at levels below those causing overt signs of clinical toxicity can produce cognitive and performance deficits. Furthermore, the observed deficits do not appear to be persistent.     

Increased endothelin-1 reactivity and endothelial dysfunction in carotid arteries from rats with hyperhomocysteinemia

Background and purpose:

There are interactions between endothelin-1 (ET-1) and endothelial vascular injury in hyperhomocysteinemia (HHcy), but the underlying mechanisms are poorly understood. Here we evaluated the effects of HHcy on the endothelin system in rat carotid arteries.

Experimental approach:

Vascular reactivity to ET-1 and ET_A and ET_B receptor antagonists was assessed in rings of carotid arteries from normal rats and those with HHcy. ET_A and ET_B receptor expression was assessed by mRNA (RT-PCR), immunohistochemistry and binding of [¹²⁵I]-ET-1.

Key results:

HHcy enhanced ET-1-induced contractions of carotid rings with intact endothelium. Selective antagonism of ET_A or ET_B receptors produced concentration-dependent rightward displacements of ET-1 concentration response curves. Antagonism of ET_A but not of ET_B receptors abolished enhancement in HHcy tissues. ET_A and ET_B receptor gene expressions were not up-regulated. ET_A receptor expression in the arterial media was higher in HHcy arteries. Contractions to big ET-1 served as indicators of endothelin-converting enzyme activity, which was decreased by HHcy, without reduction of ET-1 levels. ET-1-induced Rho-kinase activity, calcium release and influx were increased by HHcy. Pre-treatment with indomethacin reversed enhanced responses to ET-1 in HHcy tissues, which were reduced also by a thromboxane A₂ receptor antagonist. Induced relaxation was reduced by BQ788, absent in endothelium-denuded arteries and was decreased in HHcy due to reduced bioavailability of NO.

Conclusions and implications:

Increased ET_A receptor density plays a fundamental role in endothelial injury induced by HHcy. ET-1 activation of ET_A receptors in HHcy changed the balance between endothelium-derived relaxing and contracting factors, favouring enhanced contractility.British Journal of Pharmacology (2009) 157, 568–580; doi:10.1111/j.1476-5381.2009.00165.x; published online 9 April 2009This article is part of a themed section on Endothelium in Pharmacology. For a list of all articles in this section see the end of this paper, or visit: http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009     

腺相关病毒介导癌胚抗原转染树突状细胞对免疫功能的调节作用

目的:近年来,树突状细胞参与调节作用的研究较多。实验拟验证重组腺相关病毒(rAAV)介导癌胚抗原基因转染树突状细胞后其的免疫调节作用的变化。方法:实验于2006-06/2006-11在美国阿肯色大学医学院基因治疗中心完成。①实验方法:取健康人外周血(自愿捐献),采用改良Ficoll密度梯度离心的方法分离外周血单个核细胞,取贴壁细胞,分为rAAV/CEA转染组和空白对照组,均采用重组人粒细胞巨噬细胞集落刺激因子、白细胞介素4、肿瘤坏死因子-α诱导树突状细胞前体细胞成熟,将成熟树突状细胞与末梢血淋巴细胞按比例混合培养,可得到激活的细胞毒性T淋巴细胞。②实验评估:采用流式细胞仪检测树突状细胞表面标志表达,细胞毒性T淋巴细胞的免疫表型变化,细胞毒性T淋巴细胞γ-干扰素表达。采用酶联免疫吸附法(ELISA法)检测树突状细胞的白细胞介素12和白细胞介素10表达。结果:①rAAV/CEA转染树突状细胞的CD14较空白对照组降低,共刺激分子CD40、CD80、CD83、CD86表达均较空白对照组高。②成熟树突状细胞细胞因子表达中,rAAV/CEA转染组的白细胞介素12较空白对照组升高,白细胞介素10降低。③与空白对照组比较,rAAV/CEA转染组能高表达CD8 T细胞和其表型CD69,CD8/CD56的T细胞比例上调,CD25 CD4 的T细胞减少。④rAAV/CEA转染的细胞毒性T淋巴细胞表达相对较高水平的γ-干扰素,与杀伤实验结果相吻合。结论:rAAV/CEA转染树突状细胞能够激活细胞毒性T淋巴细胞的特异性杀伤作用,与树突状细胞和细胞毒性T淋巴细胞等免疫细胞表面标志变化和细胞内细胞因子水平变化相关。     

Overexpression of glutamine: fructose-6-phosphate amidotransferase in the liver of transgenic mice results in enhanced glycogen storage, hyperlipidemia, obesity, and impaired glucose tolerance

To examine the effect of increased hexosamine flux in liver, the rate-limiting enzyme in hexosamine biosynthesis (glutamine:fructose-6-phosphate amidotransferase [GFA]) was overexpressed in transgenic mice using the PEPCK promoter. Liver from random-fed transgenic mice had 1.6-fold higher GFA activity compared with nontransgenic control littermates (276 +/- 24 pmol x mg(-1) x min(-1) in transgenic mice vs. 176 +/- 18 pmol x mg(-1) x min(-1) in controls, P < 0.05) and higher levels of the hexosamine end product UDP-N-acetyl glucosamine (288 +/- 11 pmol/g in transgenic mice vs. 233 +/- 10 pmol/g in controls, P < 0.001). Younger transgenic mice compared with control mice had lower fasting serum glucose (4.8 +/- 0.5 mmol/l in transgenic mice vs. 6.5 +/- 0.8 mmol/l in controls, P < 0.05) without higher insulin levels (48.0 +/- 7.8 pmol/l in transgenic mice vs. 56.4 +/- 5.4 pmol/l in controls, P = NS); insulin levels were significantly lower in transgenic males (P < 0.05). At 6 months of age, transgenic animals had normal insulin sensitivity by the hyperinsulinemic clamp technique. Hepatic glycogen content was higher in the transgenic mice (108.6 +/- 5.2 pmol/g in transgenic mice vs. 32.8 +/- 1.3 micromol/g in controls, P < 0.01), associated with an inappropriate activation of glycogen synthase. Serum levels of free fatty acids (FFAs) and triglycerides were also elevated (FFAs, 0.67 +/- 0.03 mmol/l in transgenic mice vs. 0.14 +/- 0.01 in controls; triglycerides, 1.34 +/- 0.15 mmol/l in transgenic mice vs. 0.38 +/- 0.01 in controls, P < 0.01). Older transgenic mice became heavier than control mice and exhibited relative glucose intolerance and insulin resistance. The glucose disposal rate at 8 months of age was 154 +/- 5 mg x kg(-1) x min(-1) in transgenic mice vs. 191 +/- 6 mg x kg(-1) x min(-1) in controls (P < 0.05). We conclude that hexosamines are mediators of glucose sensing for the regulation of hepatic glycogen and lipid metabolism. Increased hexosamine flux in the liver signals a shift toward fuel storage, resulting ultimately in obesity and insulin resistance.     

The impact of adding cost information to a conversation aid to support shared decision making about low-risk prostate cancer treatment: Results of a stepped-wedge cluster randomised trial

Background

Decision aids help patients consider the benefits and drawbacks of care options but rarely include cost information. We assessed the impact of a conversation-based decision aid containing information about low-risk prostate cancer management options and their relative costs.

Methods

We conducted a stepped-wedge cluster randomised trial in outpatient urology practices within a US-based academic medical center. We randomised five clinicians to four intervention sequences and enroled patients newly diagnosed with low-risk prostate cancer. Primary patient-reported outcomes collected postvisit included the frequency of cost conversations and referrals to address costs. Other patient-reported outcomes included: decisional conflict postvisit and at 3 months, decision regret at 3 months, shared decision-making postvisit, financial toxicity postvisit and at 3 months. Clinicians reported their attitudes about shared decision-making pre- and poststudy, and the intervention's feasibility and acceptability. We used hierarchical regression analysis to assess patient outcomes. The clinician was included as a random effect; fixed effects included education, employment, telehealth versus in-person visit, visit date, and enrolment period.

Results

Between April 2020 and March 2022, we screened 513 patients, contacted 217 eligible patients, and enroled 117/217 (54%) (51 in usual care, 66 in the intervention group). In adjusted analyses, the intervention was not associated with cost conversations (β = .82, p = .27), referrals to cost-related resources (β = −0.36, p = .81), shared decision-making (β = −0.79, p = .32), decisional conflict postvisit (β = −0.34, p= .70), or at follow-up (β = −2.19, p = .16), decision regret at follow-up (β = −9.76, p = .11), or financial toxicity postvisit (β = −1.32, p = .63) or at follow-up (β = −2.41, p = .23). Most clinicians and patients had positive attitudes about the intervention and shared decision-making. In exploratory unadjusted analyses, patients in the intervention group experienced more transient indecision (p < .02) suggesting increased deliberation between visit and follow-up.

Discussion

Despite enthusiasm from clinicians, the intervention was not significantly associated with hypothesised outcomes, though we were unable to robustly test outcomes due to recruitment challenges. Recruitment at the start of the COVID-19 pandemic impacted eligibility, sample size/power, study procedures, and increased telehealth visits and financial worry, independent of the intervention. Future work should explore ways to support shared decision-making, cost conversations, and choice deliberation with a larger sample. Such work could involve additional members of the care team, and consider the detail, quality, and timing of addressing these issues.

Patient or Public Contribution

Patients and clinicians were engaged as stakeholder advisors meeting monthly throughout the duration of the project to advise on the study design, measures selected, data interpretation, and dissemination of study findings.