早产儿高胆红素血症凝血功能变化的研究

目的探讨高胆红素血症对早产儿凝血功能的影响。方法对56例出现高胆红素血症的早产儿和28例未出现高胆红素血症的早产儿进行PT,APTT,TT,FG检测。结果出现高胆红素血症的早产儿PT,APTT均延长,FG降低,与无高胆红素血症的早产儿相比有显著性差异(P<0.05),TT相比无显著性差异(P>0.05)。结论出现高胆红素血症的早产儿处于低凝血因子状态,易患出血性疾病,应及早监测凝血指标,采取有效预防措施。     

Cerebral perfusion during human liver transplantation

Summary. During transplantation of the liver cerebral perfusion was monitored by transcranial Doppler determined middle cerebral artery mean flow velocity (V_mean) and pulsatility index (PI) in six fulminant hepatic failure patients and 11 patients with chronic liver disease. In both groups of patients V_mean, PI and central haemodynamic variables were recorded during (1) the last preanhepatic hour; (2) the anhepatic phase; (3) the first 15 min of reperfusion; and (4) for the following 45 min of reperfusion. No significant differences were detected between the two groups of patients with respect to changes of variables with time. The V_mean (40±13 cm s^-1 [mean±SD]), thoracic electrical impedance (TI) (30±7 Ohm), heart rate (97±19 beats min^-1), mean arterial pressure (84±9 mmHg) and arterial carbon dioxide tension (PaCO₂, 4.5±0.4 kPa) remained stable in the anhepatic phase, while cardiac output (CO, 7.6±2.7 to 5.4±1.41 min^-1), stroke volume (SV, 79±26 to 56±15 ml) and PI (1.2±0.3 to 0.9±0.2) decreased (P<0.05). During reperfusion, CO (9.9±4.01 min^-1), SV (105±40 ml), Pa_CO2 (5.5±0.6 kPa), Vmean (57±17 cm s^-1) and PI (1.2±0.2) became elevated. Taken together, during the anhepatic phase of the liver transplantation a maintained central blood volume as indicated by the constant TI served for a stable blood pressure and in turn cerebral perfusion, whereas revascularization of the graft increased cerebral perfusion concomitant with an elevated carbon dioxide tension.     

Use of epr oximetry with india ink to measure the po2 in the liver in vivo in mice

The partial pressure of oxygen (pO₂) of the liver in vivo in unanesthetized mice was determined using electron paramagnetic resonance (EPR) oximetry with India ink. The EPR spectra were obtained using a low-frequency (1.2 GHz) EPR spectrometer with a loop gap cavity resonator. The line width of the India ink used in this experiment was reversibly broadened by oxygen and was particularly sensitive to pO₂ below 30 torr. After the administration of India ink into the tail vein, the India ink particles were taken up mainly by Kupffer cells in the liver and in part by phagocytes in the spleen. The pO₂ measured in the normal liver was about 14 torr and was constant for the 2-week experimental period. The pO₂ decreased when measured at 1, 2, and 6 days after treatment with a hepatotoxin (carbon tetrachloride (CCI₄)); within 2 weeks, it returned almost to the initial level. Measurements by EPR at sacrifice of controls and CCI₄-treated mice indicated that more than 90% of the India ink went to the liver; the spleen contained 4.7% of total amount in control mice and 8.8% in CCI₄-treated mice when measured 2 weeks after the treatment. These data indicate the usefulness of India ink for measuring the pO₂ of the liver in vivo and that the pO₂ in the Kupffer cells is decreased when the liver is damaged by CCI₄.     

Characterization of certain hepatocyte-proliferating and/or protective factors induced by the sensitization of freezing-thawing hepatic tissue

Although tumor cryosurgery would be expected to produce beneficial immunological effects from the enhancement of anti-tumor activity, under certain conditions the tumor may become enlarged and metastases promoted due to increased immunosuppressive activity and a high zone tolerance. In the present study, we examined whether hepatocyteproliferating factors were produced by the inoculation of freezing-thawing hepatic tissue (FTHT). Serum obtained from rats inoculated with FTHT increased DNA synthesis, according to measurement by [³H]thymidine incorporation in primary cultured rat hepatocytes. This increase was dependent on the serum concentration, with serum obtained on day 14 after the inoculation being the most potent for hepatocyte proliferation. The sensitized serum promoted DNA synthesis nearly as much as serum obtained from a 70% hepatectomized rat, but slightly less than 10ng/ml hepatocyte growth factor. The sensitized serum also protected hepatocytes from carbon tetrachloride (CCI₄)-induced hepatotoxicity. Optical density measured by the 3-(4,5-dimethyl-thiazole-2-yl)-2,5-diphenyl tetrozolium bromide (MTT) cytotoxicity assay was increased, and the release of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in medium was decreased by treating hepatocytes damaged by CCI₄ with the sensitized serum. These results suggest that certain hepatocyte-proliferating and protective factors are induced in serum by the inoculation of freezing-thawing hepatic tissue, and that the sensitized serum may be useful in the treatment of liver failure.     

CO作用后大鼠肺血管细胞增殖和凋亡状况的研究

目的：通过研究CO和低氧作用后大鼠肺血管细胞增殖和凋亡状况，探讨低氧肺动脉高压的发病机制及防治措施。方法：应用免疫组织化学，原位末端标记及Western杂交等方法检测常压低氧大鼠肺血管壁细胞增殖，凋亡及c-myc基因的表达状况。结果：正常组，低氧和锡原卟啉组，低浓度CO和血晶素组大鼠肺动脉均存在增殖和凋亡的阳性细胞，两类细胞在肺内呈不均匀散在分布，低氧和锡原卟啉组大鼠肺血管增殖细胞数显著升高而凋亡细胞数显著减少，细胞增殖凋亡比值分别为对照组的5倍或4倍，而低浓度CO和血晶素组肺血管增殖细胞和凋亡细胞系数均显著增加，细胞增殖凋亡比值均为1．2，c-myc在低氧和锡原卟啉组大鼠肺内表达显著增加，在低浓度CO和血晶素组大鼠肺内表达减少。结论：增殖和凋亡现象共存在于正常和处理大鼠的肺血管细胞中，也许c-myc等基因的异常表达导致了细胞增殖和凋亡的失衡，进而调节了慢性低氧肺血管结构的改建。     

Local variations in the cerebral microcirculatory response to hypercapnia and haemorrhage

Summary This study evaluates local variations of the cerebral vasomotor responses to hypercapnia and haemorrhagic hypotension in a pig model. Four laser Doppler flow probes were used in each pig. There was considerable variation in laser Doppler signals between the four probes in baseline recordings. The increases in flow after CO₂ administration in 7 pigs had a mean coefficient of variation of 0.43 ± 0.31, and the flow changes after blood loss in another 7 pigs had a mean coefficient of variation of 0.45 ± 0.34. The range of flow changes within each animal was large; the probe with the highest CO₂ response showed on the average a 273% ± 157% larger CO₂ response than the probe with the lowest CO₂ response. Correspondingly, the probe with the best preserved blood flow after blood loss had on the average a flow value of 93% ± 12% of the baseline value, while the probe that changed most with haemorrhage had a flow value of 44% ± 24% of the baseline value. Single laser Doppler recordings have been used for the monitoring of cerebral blood flow in neurosurgical critical care, but our results suggest that a single laser Doppler flow probe is not an adequate method to monitor vasoreactivity in neurosurgical patients because flow signals from one probe may be unrepresentative for other sites in the brain.     

Cardiac metabolism: A technical spectrum of modalities including positron emission tomography,single-photon emission computed tomography,and magnetic resonance spectroscopy

Noninvasive techniques for the assessment of cardiac metabolism are important for the detection of potentially salvageable tissue in jeopardized areas of the myocardium. The correct identification of hibernating and stunned myocardium in patients with severely depressed cardiac function can have vital therapeutic consequences for the patient. Changes in myocardial fatty acid and glucose metabolism during acute and prolonged ischemia can be traced by positron-emitting or gamma-emitting radiopharmaceuticals. Alternatively,³¹P-labeled magnetic resonance spectroscopy can be used for the assessment of high-energy phosphate metabolism. It is not yet clear which modality will emerge as the most useful in the clinical setting. Positron emission tomography (PET) that uses combinations of flow tracers and metabolic tracers offers unique opportunities for quantification and high-resolution static and rapid dynamic studies. Currently, assessment of glucose metabolism with¹⁸F-fluorodeoxyglucose is regarded as the gold standard for myocardial viability and prediction of improvement of impaired contractile function after revascularization. However, preserved oxidative metabolism may be required for potential functional improvement, and therefore assessment of residual oxidative metabolism by¹¹C-labeled acetate PET may prove to be more accurate than¹⁸F-fluorodeoxyglucose PET, which reflects both anaerobic and oxidative metabolism. Moreover, because fatty acids are metabolized only aerobically, they are excellent candidates for the clinical assessment of myocardial viability and prediction of functional improvement after revascularization. Especially derivatives of fatty acids that are not metabolized but accumulate in the myocyte are attractive for myocardial imaging. Examples are¹²³I-beta-methyl-p-iodophenyl pentadecanoic acid and 15-(o-¹²³I-phenyl)-pentadecanoic acid. These tracers can be detected by planar scintigraphy and single-photon emission computed tomography, which are more economical and widely available than PET. In addition, 511 keV collimators have been developed recently, making the detection of positron emitters by planar scintigraphy and single-photon emission computed tomography feasible. The experience with³¹P-labeled magnetic resonance spectroscopy in humans is still limited. With current magnetic resonance spectroscopic techniques, insufficient spatial resolution is achieved for clinical purposes, but the possibility of serial measurements to monitor rapid changes of phosphate-containing molecules in time makes magnetic resonance spectroscopy very valuable for the research of myocardial metabolism.     

小柴胡汤口服液药效作用的研究

观察了小柴胡汤口服液的主要药理作用。研究表明,小柴胡汤口服液有显著抑制角叉菜胶诱发的大鼠踝关节水肿(p<0.05),保护四氯化碳所致的大鼠急性肝功能损害,有极显著降低血清SGPT及LDH的作用(P<0.01)。对家兔发热反应也有较好的抑制作用。此外,小柴胡汤口服液对小鼠兔疫反应也有一定的增强作用,可促进小鼠碳粒廓清速率,提高血清溶血素水平及增强鸡红细胞所致的迟发性过敏反应。     

cAMP对胰岛素刺激的NIH3T3细胞丝裂原激活蛋白激酶活性的抑制作用

目的 探讨cAMP-PKA信号途径对胰岛素激活的Ras-丝裂原激活蛋白激酶(MAPK)信号途径的影响。方法 以3-异丁基-1-甲基黄嘌呤(IBMX)提高细胞内环腺苷酸(cAMP)浓度，藉四唑蓝比色法(MTT法)和蛋白免疫印迹试验分别观察cAMP对胰岛素刺激的小鼠成纤维细胞(NIH3T3细胞)的生长增殖和胞内丝裂原激活蛋白激酶(MAPK)活性的影响。结果 IBMX(0．5mmol/L)抑制静息的和胰岛素(10mU／mL)刺激的NIH3T3细胞的增殖，作用呈时间依赖性。在胰岛素(10mU／mL)刺激的NIH3T3细胞，MAPK出现酪氨酸磷酸化；而以IBMX(0．5mmol/L)预处理细胞30min后，再以胰岛素作用10min，胰岛素刺激的MAPK的酪氨酸磷酸化受抑制。结论：cAMP可通过抑制MAPK磷酸化活化对NIH3T3细胞增殖起抑制作用。