款冬花粗多糖体外诱导人白血病K562细胞的凋亡

目的:观察款冬花粗多糖对体外培养人白血病K562细胞有无凋亡诱导作用。方法:实验于2006-06-25/2006-09-08在河北北方学院实验中心细胞生物学实验室、分子生物学实验室、药物研究实验室完成。①款冬花粗多糖的提取:称取已干燥粉粹的款冬花417.0g,加入1000mL体积分数0.85乙醇回流提取1h,滤过,滤渣加入1000mL三蒸水回流提取2h,过滤,滤渣再加入1000mL三蒸水回流提取2h,合并2次滤液,减压浓缩至适量,四倍体积无水乙醇醇沉,静置过夜,过滤,沉淀依次用无水乙醇、丙酮、石油醚洗涤,即得款冬花粗多糖。苯酚-硫酸法测定款冬花粗多糖含量以生药计算为122.9mg。制成102.5g/L粗多糖溶液。②人白血病K562细胞的生长抑制实验:体外培养的K562细胞经10,30,50,70,90mg/L的款冬花粗多糖作用48h后,通过Hoeehst33258染色在荧光显微镜下进行形态学观察、采用琼脂糖凝胶电泳及流式细胞术检测细胞凋亡。结果:①经款冬花粗多糖作用后,荧光显微镜下发现体外培养的K562细胞中出现核固缩、凋亡小体。②经不同质量浓度款冬花粗多糖处理的K562细胞DNA电泳均出现相差约200bp的DNA梯子状条带。③流式细胞仪检测发现,经不同质量浓度款冬花粗多糖处理的K562细胞,有凋亡峰。结论:款冬花粗多糖可诱导体外培养人白血病细胞K562凋亡。     

Dissociated expression of mitochondrial and cytosolic creatine kinases in the human brain: a new perspective on the role of creatine in brain energy metabolism

The phosphocreatine/creatine kinase (PCr/CK) system in the brain is defined by the expression of two CK isozymes: the cytosolic brain-type CK (BCK) and the ubiquitous mitochondrial CK (uMtCK). The system plays an important role in supporting cellular energy metabolism by buffering adenosine triphosphate (ATP) consumption and improving the flux of high-energy phosphoryls around the cell. This system is well defined in muscle tissue, but there have been few detailed studies of this system in the brain, especially in humans. Creatine is known to be important for neurologic function, and its loss from the brain during development can lead to mental retardation. This study provides the first detailed immunohistochemical study of the expression pattern of BCK and uMtCK in the human brain. A strikingly dissociated pattern of expression was found: uMtCK was found to be ubiquitously and exclusively expressed in neuronal populations, whereas BCK was dominantly expressed in astrocytes, with a low and selective expression in neurons. This pattern indicates that the two CK isozymes are not widely coexpressed in the human brain, but rather are selectively expressed depending on the cell type. These results suggest that the brain cells may use only certain properties of the PCr/CK system depending on their energetic requirements.     

Alarm settings for the Marquette 8000 pulse oximeter to prevent hyperoxic and hypoxic episodes

OBJECTIVE: To determine safe and appropriate alarm limits for the Marquette 8000 pulse oximeter to prevent hyperoxic and hypoxic episodes in neonates. It is necessary to define these limits for each brand of oximeter because of the variance in nonuser adjustable calibration algorithms used in pulse oximeters. METHODOLOGY: Oxygen saturation values obtained from a Marquette 8000 pulse oximeter (SpO2) were compared with simultaneous arterial blood gas PaO2 values obtained from blood gas analysis, for 322 samples in 24 consecutive neonates (median 30 weeks' gestation). RESULTS: In order to prevent 95% of hyperoxic episodes (PaO2 > 90 mmHg), the upper alarm limit was 95% SpO2. Similarly, to prevent 95% of hypoxic episodes (PaO2 < 40 mmHg), the lower alarm limit was 95% SpO2. A sensitivity lower than 95% had to be accepted to develop an alarm range which prevented both hyperoxic and hypoxic episodes. To maintain PaO2 values between 40 and 90 mmHg, an appropriate alarm range of 94-97% SpO2 (90% sensitivity, 28% specificity) was established. CONCLUSIONS: The relative merits of high sensitivity versus high specificity should be considered when determining appropriate alarm limits. Alarm limits which represent a balance between sensitivity and specificity will minimise false alarms and provide a clinically practical range. It would be useful for this type of information to be available for each brand of oximeter, to assist the user in determining appropriate alarm settings.     

Height and weight in cystic fibrosis: a cross sectional study. UK Cystic Fibrosis Survey Management Committee

Cross sectional data reporting the height, weight, and body mass index of UK patients with cystic fibrosis are presented. During the first decade of life height and weight in patients with cystic fibrosis are maintained at about 0.5 SD below those of the general population, which reflects an improvement over earlier published observations. Postpubertal stature and weight maintenance in the cystic fibrosis population still show substantial deficits which may be related to treatment.     

The effect of recombinant GM-CSF on the recovery of monkeys transplanted with autologous bone marrow

The regulatory function of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) on granulocyte production in vivo was evaluated in an autologous bone marrow transplantation model using rhesus monkeys. Monkeys were exposed to 9.0 Gy total body irradiation and then transplanted with 5.0 x 10(7) low-density bone marrow cells/kg. Alzet miniosmotic pumps were subcutaneously implanted to deliver rhGM-CSF at a rate of 50,400 U/kg/d. Minipumps, containing either rhGM-CSF or saline, were implanted between zero and five days after transplantation for seven days. Kinetic recoveries of peripheral blood cells after either saline or rhGM-CSF treatment were compared. Treatment with rhGM-CSF accelerated the recovery of neutrophils. Neutrophils in rhGM-CSF-treated animals recovered to 80% (3.4 x 10(3)/mm3) pre-irradiation control levels by day 20, in comparison with only 33% (0.9 x 10(3)/mm3) recovery for saline control monkeys. In addition, the recovery of neutrophils was enhanced over that of the controls, reaching 140% v 70% on day 30. Another prominent feature of rhGM-CSF-treated monkeys was the accelerated recovery of platelets, reaching near 50% normal levels by day 24 in comparison with 20% of normal levels for controls. The infusion of rhGM-CSF was shown to be an effective regulator of early hematopoietic regeneration, leading to the accelerated recovery of both neutrophils and platelets and then providing a consistent sustained increase of neutrophils even in the absence of rhGM-CSF.     

GEOSPATIAL ECOLOGY OF ADOLESCENT PROBLEM BEHAVIOR: CONTRIBUTIONS OF COMMUNITY FACTORS AND PARENTAL MONITORING

We addressed the ecology of deviant peer involvement, antisocial behavior, and alcohol use using publicly available information for indices of community risk/protective factors. A geospatial model was developed, combining geographic data (census, crime proximity, race/ethnicity, and transportation accessibility) with information gathered from individual adolescents/households, geocoded by home address. Adolescent report of delinquency, association with deviant peers, substance use, and parental monitoring were obtained, along with parent report of demographic characteristics. Deviant peer involvement was predicted by the Crime Proximity Index, with closeness of crime being associated with more deviant peer affiliation, as well as the Transportation Index, with greater accessibility leading to more involvement with troubled peers. Antisocial behaviors also increased with greater access to transportation. Adolescent alcohol use was lower in communities with a higher proportion of a non‐Caucasian population and increased with greater transportation access. Adolescent outcomes were associated with different prediction models, yet parental monitoring emerged as a consistent contributing factor.