枸橼酸咖啡因与氨茶碱对早产儿神经行为发育影响分析

目的 比较枸橼酸咖啡因和氨茶碱对早产儿神经行为发育的影响,为早产儿早期合理干预提供临床依据。方法 选择2014年6月-2018年6月在中国西电集团医院新生儿科住院接受枸橼酸咖啡因治疗的原发性呼吸暂停(AOP)早产儿62例作为研究组;2011 年 12 月-2014年5月同在中国西电集团医院新生儿科住院采用氨茶碱治疗的AOP患儿69例作为对照组。出生3~8 d及矫正胎龄40周时分别行头颅MRI检查,评估脑白质损伤(WMD)并进行两组比较;6个月及12个月时应用Gesell婴幼儿发育量表测试比较两组神经行为发育水平。结果 两组患儿在性别、出生胎龄及体重、产前孕母糖皮质激素应用及分娩方式、5 min Apgar评分、辅助通气和表面活性物质的应用等方面差异均无统计学意义(P>0.05)。首次头颅MRI显示两组患儿WMD差异无统计学意义(P>0.05)。矫正胎龄40周时头颅MRI显示,咖啡因组WMD较氨茶碱组明显改善,差异有统计学意义(P<0.05);且6个月及12个月时Gessell婴幼儿发育量表测试,随访至校正6月龄时,咖啡因组患儿的大运动、精细运动及个人-社交评分均高于氨茶碱组(P<0.05);随访至校正12月龄时,咖啡因组患儿的大运动、精细运动、语言、适应性评分均高于氨茶碱组(P<0.05)。结论 枸橼酸咖啡可明显改善AOP患儿6个月及12个月时的神经行为发育。     

The effects of changes to action potential duration on the calcium content of the sarcoplasmic reticulum in isolated guinea-pig ventricular myocytes

. We have estimated sarcoplasmic reticulum calcium content using rapid application of caffeine on voltage clamped, isolated guinea-pig ventricular myocytes. Caffeine induces the release of calcium from the sarcoplasmic reticulum and this calcium is extruded from the cells by the sarcolemmal Na/Ca exchange. Integrating the inward Na/Ca exchange current thus allows estimations of sarcoplasmic reticulum calcium content. Ventricular myocytes were stimulated to reach new steady-states by action potential voltage clamps of varying duration. Once contractile steady-state had been reached caffeine was rapidly applied in place of the next action potential and sarcoplasmic reticulum calcium content measured. Prolonging the action potential duration increased sarcoplasmic reticulum calcium content and vice-versa. This calcium loading may underlie the positive inotropic effect of increased action potential duration. Received: 11 July 1996 / Received after revision: 15 October 1996 / Accepted: 26 November 1996     

Immunoelectron microscopic studies on centromere-kinetochore complexes detached from chromosomes

The centromere-kinetochore complexes of Chinese hamster ovary (CHO) cells were detached and separated from the condensed chromatin by treatment with hydroxyurea and caffeine. By labelling the complex for immunoelectron microscopy (immuno-EM) with a mixture of antibodies against centromere proteins (anti-CENP-A,-B, -C) in some cells, we could demonstrate complete detachment of the complexes. No remnants were left at the bulk of condensed chromatin in these cells. In some mitotic cells complex and chromatin were found side by side. It could be shown that the fine structure of the separated material of the complex differs significantly from that of the rest of chromatin. The complex consists of proteins and DNA. This leads us to suppose that the organization of chromatin in the centromere-kinetochore complex is different.     

噪声和咖啡因联合作用对血液中TG、Ch、LDL和HDL含量的影响

用自动生化分析仪对接触强噪声的纺织女工饮用咖啡前后和不接触强噪声的女大学生进行了血液TG、Ch、LDL和HDL含量测定。结果发现:噪声可使血液TG、Ch及LDL含量显著升高,而噪声和咖啡(含咖啡因)联合作用后其血液TG、Ch及LDL含量明显降低,HDL含量升高,提示咖啡因可拮抗噪声所致的脂代谢异常。     

Effect of temperature variation (22˚C- 44˚C) on halothane and caffeine contracture testing in normal humans

Background: Malignant hyperthermia (MH) susceptibility is diagnosed using halothane-caffeine contracture testing of a muscle sample maintained at 37˚C. However, there has not been a systematic study that examines the effect of different temperatures on the response of normal muscle to halothane and caffeine. We hypothesized that altering bath temperature would modify the contracture responses.
Methods: We obtained muscle samples from 20 patients undergoing surgical procedures of the lower extremities. The samples were dissected into 245 bundles and the bundles were exposed to halothane 3% or incremental caffeine, according to the North American MH group protocol. Several bundles from each patient were simultaneously studied at four different temperatures (22˚C, 30˚C, 37˚C and 44˚C). Each bundle was studied at only one temperature, the muscle samples of 3 patients were simultaneously studied at all four temperatures for halothane and caffeine.
Results: Maximum contracture to caffeine (32 mM) was highest at 37˚C; however, at lower caffeine concentrations (2–4 mM), there was no consistent effect of temperature on contracture response. Likewise, temperature did not alter contracture responses to halothane. The extremes of temperature (22˚C and 44˚C) were associated with lack of twitch in response to electrical stimulation. For the bundles exposed to halothane at 22"C, the absence of a twitch was associated with the presence of a contracture, although these were never above the diagnostic threshold.
Conclusions: We conclude that temperature has little effect on responses of normal muscle to halothane and caffeine.     

Different effects of halothane, isoflurane and sevoflurane on sarcoplasmic reticulum of vascular smooth muscle in dog mesenteric artery

Background: The direct effect of halothane on vascular smooth muscle is mediated in part via its effects on the sarcoplasmic reticulum (SR). Little information is available concerning the effects of other volatile anesthetics including isoflurane and sevoflurane, whose vascular effects differ from those of halothane. The aim of the present study was to compare the effects of halothane, isoflurane and sevoflurane on the SR by testing the contraction induced by caffeine in vascular smooth muscle. Methods: Rings without endothelium from isolated canine mesenteric artery were mounted in physiological saline solution (PSS) for isometric tension recording. After complete depletion of Ca²⁺ from the SR by adding 35 mM caffeine, the rings were exposed to normal Ca²⁺ containing PSS (Ca²⁺ loading), to Ca²⁺-free PSS for 10 min, and then to 15 mM caffeine to induce contraction. Anesthetics were administered during Ca²⁺ loading, the Ca²⁺-free phase and simultaneously with caffeine administration. Results: Halothane (0.5-2%) attenuated the caffeine-induced contraction of canine mesenteric artery when administered during Ca²⁺ loading in the SR (P<0.001), whereas isoflurane and sevoflurane (1–4%) failed to affect the contraction. When given simultaneously with caffeine, halothane (1–2%) potentiated the caffeine-induced contraction (P<0.05), but isoflurane and sevoflurane had no effect. When given before caffeine administration, halothane (0.5-2%), isoflurane (24%) and sevoflurane (4%) all potentiated the caffeine-induced contraction (P<0.05). Conclusion: It has been shown that halothane not only potentiates caffeine- induced Ca²⁺ release from the SR, but also induces contraction by releasing Ca²⁺ from the SR. We conclude that halothane decreases Ca²⁺ accumulation in the SR while exerting facilitative and additive effects on caffeine-induced Ca²⁺ release from the SR when applied before caffeine administration and simultaneously with caffeine, respectively, whereas isoflurane and sevoflurane lack both the ability to decrease Ca²⁺ accumulation and an additive effect on caffeine-induced Ca²⁺ release from the SR, but are able to facilitate Ca²⁺ release by caffeine.     

In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European MH Group: Results of testing patients surviving fulminant MH and unrelated low-risk subjects

Background: Determination of sensitivity and specificity of the in vitro contracture test (IVCT) for malignant hyperthermia (MH) susceptibility using the European MH Group (EMHG) protocol has been performed in some laboratories but only on a small sample from the combined EMHG. Thus, the purpose of the present study was to determine combined EMHG sensitivity and specificity of the test. Methods: Results of IVCT of patients with previous fulminant MH and normal, low-risk subjects (controls) were collected from 22 centresof the EMHG. IVCT was performed according to the EMHG protocol. Patients were included inthe study if the clinical crisis had a score of at least 50 points with the Clinical Grading Scale. Low-risk subjects were included provided they did not belong to a family with known MH susceptibility, they had not developed any signs of MH at previous anaesthetics, and they did not suffer from any neuromuscular disease. For inclusion of both MH patientsand low-risk subjects, at least 1 muscle bundle in the IVCT should have twitches of 10 mN(1 g) or more. For evaluation of individual tests, only muscle bundles with twitch heights of 10 mN (1 g) or more were used. Results: A total of 1502 probands had undergone IVCT because of a previous anaesthesia with symptoms and signs suggestive of MH. Of these, 119 had clinical scores of 50 and above. From these 119 MH-suspected patients and from 202 low-risk subjects, IVCT data were collected. Subsequently, 14 MH-suspected patients were excluded from further analysis for thefollowing reasons: In 3 patients, the suspected MH episode could be fully explained by diseases other than MH; in 11 MHS patients, IVCT was incomplete (n=l), data were lost (n=3), or none of the muscle bundles fulfilled twitch criteria (n=7). Of the remaining 105 MH-suspected patients, 89 were MHS, 10 MHEh, 5 MHEc, and one MHN. Thus, we observed a diagnostic sensitivity of the IVCT of 99.0% if the MHE group is considered susceptible(95% confidence interval 94.8–100.0%). Of the 202 low-risk subjects, 3 were MHS, 5 MHEh, 5 MHEc, and 189 MHN. This gives a specificity of the IVCT of 93.6% (95% confidence interval 89.2–96.5%). Conclusion: The IVCT for diagnosis of MH susceptibility in Europe has a high sensitivity and a satisfactory specificity.     

Age, fiber type composition and in vitro contracture responses in human malignant hyperthermia

Muscle fiber typing and in vitro contracture tests were performed in 59 patients investigated for susceptibility to malignant hyperthermia (MH). Eighteen patients were found to be susceptible to MH. There was no difference in age or fiber type distribution between MH susceptible and non-susceptible patients. No correlation was found between age and fiber type distribution. Separate analyses for each diagnostic group revealed no relationship between age or fiber type distribution and response to halothane or caffeine. When all caffeine results were pooled, however, there was a significant effect of age on the caffeine specific concentration (the concentration eliciting a contracture of 1 g), but not on the caffeine threshold concentration (the minimal concentration eliciting an increase in tension). It is concluded that age and fiber type distribution have no influence on MH diagnosis, if the protocol of the European MH Group for evaluation of susceptibility to MH is followed.