La cafeína atenúa daño hepático y mejora signos neurológicos en un modelo de encefalopatía hepática con ratas

Introduction and aimsCirrhosis is the common outcome of liver diseases. It can be decompensated and lead to the development of complications, such as encephalopathy. Hyperammonemia that develops due to liver dysfunction is etiopathologically related to hepatic encephalopathy. Caffeine increases the activity of the urea cycle in the liver, augmenting ammonia degradation. By antagonizing adenosine receptors, it also has a hepatoprotective effect, impeding the formation of fibrosis, as well as having a stimulating effect on the central nervous system. The present study analyzed the effects of caffeine on the progression of cholestatic liver fibrosis and hepatic encephalopathy.Materials and methodsAn experimental model of cholestatic liver fibrosis, through common bile duct ligature, and of hepatic encephalopathy, through the administration of a high-protein diet, was constructed. Male Wistar rats (n = 32) were equally divided into 4 groups. The experiment lasted 28 days, with the administration of 50 mg/kg/day of caffeine. Laboratory tests, histologic analyses of the liver and encephalon, open field tests (OFTs), and daily behavioral analyses were carried out.ResultsThe ligated animals treated with caffeine had lower mean transaminase levels and improved histologic aspects of the liver and encephalon. The untreated ligated animals were clearly lethargic and apathetic at the last week of the experiment, confirmed by reduced exploratory activity during the OFT.ConclusionCaffeine improved the microarchitecture of the liver and encephalon of the cirrhotic animals and prevented the decrease in exploratory behavior of the animals during the OFT.     

Effects of exogenous factors on spatial accuracy in neurosurgery

The study aimed to assess the effect of exogenous factors such as surgeon posture, surgical instrument length, fatigue after a night shift, exercise and caffeine consumption on the spatial accuracy of neurosurgical manipulations. For the evaluation and simulation of neurosurgical manipulations, a testing device developed by the authors was used. The experimental results were compared using nonparametric analysis (Wilcoxon test) and multivariate analysis, which was performed using mixed models. The results were considered statistically significant at p < 0.05. The study included 11 first-year neurosurgery residents who met the inclusion criteria. Hand support in the sitting position (Wilcoxon test p value = 0.0033), caffeine consumption (p = 0.0058) and the length of the microsurgical instrument (p = 0.0032) had statistically significant influences on the spatial accuracy of surgical manipulations (univariate analysis). The spatial accuracy did not significantly depend on the type of standing position (Wilcoxon test p value = 0.2860), whether the surgeon was standing/sitting (p = 0.1029), fatigue following a night shift (p = 0.3281), or physical exertion prior to surgery (p = 0.2845).When conducting the multivariate analysis, the spatial accuracy significantly depended on the test subject (p < 0.0001), the use of support during the test (p = 0.0001), and the length of the microsurgical instrument (p = 0.0397). To increase the spatial accuracy of microsurgical manipulations, hand support and shorter tools should be used. Caffeine consumption in high doses should also be avoided prior to surgery.     

枸橼酸咖啡因与氨茶碱对早产儿不同时相血糖值的影响比较

目的观察并比较枸橼酸咖啡因及氨茶碱对早产儿不同时相血糖的影响程度。方法选择新生儿监护室诊断为原发性呼吸暂停的出生胎龄＜34周的早产儿172例，采用随机数字表法分为咖啡因组与氨茶碱组各86例。比较两组早产儿用药前及用药后15、30min、1、1.5、2、4、6、12、12.5、24.5、36.5和48h血糖的变化。结果两组早产儿用药后除6、12和48h血糖值比较差异均无统计学意义（均P＞0.05），其他用药后时相比较差异均有统计学意义（均P＜0.05）。咖啡因组早产儿用药后30min血糖值上升，至1h达峰值，后逐渐回落；用药后30min、1、1.5、2及24.5h血糖值与用药前比较差异均有统计学意义（均P＜0.05）。氨茶碱组早产儿用药后血糖值上升，30min达峰值，后逐渐回落；用药后15、30min、1、1.5、2、4、6、12.5、24.5、36.5h血糖值与用药前比较差异均有统计学意义（均P＜0.05）。结论枸橼酸咖啡因可引起早产儿血糖升高，但升高幅度较氨茶碱小、持续时间也较短。     

预防性持续低剂量咖啡因治疗超低出生体质量儿呼吸暂停疗效观察

目的：观察预防性持续低剂量咖啡因在超低出生体质量儿呼吸暂停治疗中的临床疗效。方法将超低出生体质量儿208例随机分为试验组和对照组各104例。试验组患儿在出生后尚未发生呼吸暂停时给予持续低剂量咖啡因治疗,对照组患儿在发生呼吸暂停后才开始接受咖啡因治疗。比较并评价2组患儿治疗效果。结果试验组在患儿出生1周内呼吸暂停发生率和体质量增至2.0kg前呼吸暂停发生率均低于对照组,差异均有统计学意义（P＜0.05）。试验组反复发生呼吸暂停而使用呼吸机的百分率低于对照组,差异有统计学意义（P＜0.05）。结论持续低剂量咖啡因用于预防超低出生体质量儿呼吸暂停,能够有效缓解患儿的病症。     

HPLC法测定新复方大青叶片中对乙酰氨基酚、咖啡因、没食子酸的含量

目的：建立高效液相色谱法测定新复方大青叶片中对乙酰氨基酚、咖啡因、没食子酸的方法。方法采用 Phenomenex Luan C18柱（250mm ×4．6mm,5μm）色谱柱,以0．1％磷酸溶液－乙腈（80∶20）为流动相,流速为1．0mL? min －1,检测波长为210nm。结果对乙酰氨基酚在38．02～380．25μg范围内,呈良好的线性关系（r＝0．9998）,平均回收率为99．92％,RSD为0．28％（n＝9）;咖啡因在3．838～38．375μg范围内,呈良好的线性关系（ r＝0．9999）,平均回收率为99．67％, RSD 为0．18％（ n ＝9）;没食子酸在1．08～10．8μg 范围内,呈良好的线性关系,（ r ＝0．9999）,平均回收率为98．34％,RSD为0．60％（n＝9）。结论本方法准确、重复性好,可用于该制剂的质量控制。     

Caffeine intake in pregnancy: Relationship between internal intake and effect on birth weight

We used a physiologically based kinetic model to simulate caffeine blood concentration-time profiles in non-pregnant and pregnant women. The model predicted concentration-time profile was in good accordance with experimental values. With 200 mg, the safe dose per occasion in non-pregnant women, AUC and peak concentration in pregnant women were nearly twice that of non-pregnant women. In order to derive a safe dose for the pregnant women we estimated the dose in the pregnant women model taken at once which would not exceed AUC and peak concentration in the non-pregnant women of 200 mg as single dose. The resulting dose is 100 mg caffeine per occasion which we recommend as safe.The caffeine dose of 200 mg per day is declared as safe for pregnant women with respect to the foetus by EFSA based on results on reduced birth weight in epidemiological studies. We modelled AUC and peak concentration for different caffeine doses to investigate the relationship between internal caffeine exposure and risk measures of reduced birth weight from epidemiological studies. The graphical analysis revealed that the reduction in birth weight was related to AUC and peak concentration up to a dose of 250 mg caffeine.