1,25-二羟维生素D_3抑制报导载体pGL_2荧光素酶表达的研究

通过磷酸钙沉淀法将载体DNA转染Caco－2细胞。Caeo－2细胞经不同浓度1,25一二羟维生素D3处理后,测定表达的荧光素酶活性。结果;当pSG5－VDR表达载体共转染时1,25一二羟维生素D3显著地抑制Caco－2细胞荧光素酶的表达;而未使用pSG5－VDR表达载体共转染时,则无抑制作用。说明1,25一二羟维生素D3能抑制报导载体pGL2荧光素酶的表达。类似于人类PTH基因中的潜在抑制性VDRE存在于报导载体pGL2。     

Morphological and functional demonstration of rat dura mater mast cell-neuron interactions in vitro and in vivo

The effects of changes in temperature on primary and secondary endings of isolated cat muscle spindles were investigated under ramp-and-hold stretches and different degrees of pre-stretch. Temperature-induced alterations of the discharge frequency were compared over a temperature range of 25–35°C. Both primary and secondary endings responded to warming with increasing discharge frequencies when the spindle was pre-stretched by 5–10% of its in situ length. The following differences between the temperature effects on primary and secondary endings were observed: (1) The temperature coefficients (Q₁₀) obtained from the discharge frequencies during the dynamic and static phase of a stretch were similar for endings of the same type, but they were larger in primary endings (range of Q₁₀: 2.3–3.3; mean: 2.9) than in secondary endings (range of Q₁₀: 1.6–2.2; mean: 2.0); (2) With primary endings, but not with secondary endings, the temperature sensitivity (imp s⁻¹ °C⁻¹) was larger during the dynamic phase than during the static phase of a stretch; (3) In primary endings, the fast and slow adaptive components occurring in the discharge frequency during the static phase of a stretch clearly increased with warming while in secondary endings, the slow decay was less affected, and the fast decay showed no change; (4) In relaxed spindles, the excitatory effect of warming was overlaid by a strong inhibitory effect as soon as the temperature exceeded about 30°C, resulting in an abrupt cessation of the background activity in most secondary endings, but not usually in primary endings. In general, warming induced an enhanced stretch sensitivity in both types of ending, and additionally an inhibitory effect that is obvious only in secondary endings of relaxed spindles. The different effects of temperature on the discharge frequency of primary and secondary afferents are assumed to be caused by different properties of their sensory membranes.     

An analysis of an air-ambulance program for children

Air-ambulance services are extremely expensive to operate and maintain. The value of their existence has been questioned in this era of rationalization and downsizing. We examined the cost, safety, flight crew composition, types of trauma, and effectiveness of our air-ambulance program at the Children's Hospital of Eastern Ontario (CHEO) over a 3-year period, 1994-1997. During this time, 392 children were aeroevacuated to CHEO, 113 surgical (29%), 136 medical (35%), and 143 neonates (36%). Of the surgical cases, 43% were transferred for orthopaedic trauma, the commonest being fractured femur, 23% for general surgical cases, most common being thoracoabdominal trauma, and 22% for neurosurgical reasons, most commonly basilar skull fractures. The average response time (time from which the call was received to the time when the helicopter reached the patient site) for all of the cases was 46 min. The average travel time (time from departure of patient site to arrival at CHEO) for these same cases was 25.59 min. The air-ambulance program for children in the Ottawa-Carleton Eastern Ontario areas, was found to be safe, effective, and allowed earlier specialized medical care to be provided.     

维生素D_3对报告载体荧光素酶表达的作用

目的：　研究１,２５－二羟维生素Ｄ３ 对结肠癌细胞系Ｃａｃｏ－２ 细胞中报告基因表达的作用,并探讨在报告载体ｐＧＬ２ 序列中存在潜在的抑制性维生素Ｄ应答元件（ＶＤＲＥ）的可能性。方法：　采用磷酸钙沉淀法将报告载体转染入Ｃａｃｏ－２ 细胞。Ｃａｃｏ－２细胞经不同浓度１,２５－二羟维生素Ｄ３ 处理后测定细胞裂解液中表达的荧光素酶活性。结果：　应用ｐＧＬ２ 报告载体时,当用ｐＳＧ５－ＶＤＲ表达载体共转染后,１,２５－二羟维生素Ｄ３显著地抑制Ｃａｃｏ－２ 细胞荧光素酶的表达（Ｐ＜ ０．０５）;而未使用该表达载体共转染则无抑制作用（Ｐ＞ ０．０５）。应用ｐＧＬ３ 报告载体时,不同浓度的１,２５－二羟维生素Ｄ３ 对ｐＬＧ３转染后Ｃａｃｏ－２ 细胞表达的荧光素酶活性均无显著抑制作用（Ｐ＞ ０．０５）,该作用不依赖是否存在有ｐＳＧ５－ＶＤＲ表达载体共转染。结论：１,２５－二羟维生素Ｄ３ 对报告载体ＰＧＬ２ 荧光素酶表达具有抑制作用,而对ｐＧＬ３ 则否;类似人类ＰＴＨ基因中的潜在抑制性ＶＤＲＥ存在于报告载体ｐＧＬ２,在ｐＧＬ３ 中该ＶＤＲＥ业已改变。     

健康寿命年——一个新的测量疾病负担的指标

介绍一种新的测量疾病负担的指标——健康寿命率（ＨｅａＬＹ）。我们用此指标对１９９０～１９９３年北京ＭＯＮＩＣＡ资料进行了重新估算和分析,并将其与几年前ＷＨＯ和世界银行提出的另一个测量疾病负担的指标ＤＡＬＹ进行了比较。     

放射状角膜切开手术中微穿孔对角膜内皮的影响

目的：评价放射状角膜切开术（ＲＫ）中微穿孔对术后１年内角膜内皮的影响。方法：应用角膜内皮镜及角膜内皮分析仪研究４８例ＲＫ术中微穿孔和未穿孔眼的角膜内皮形态学变化,分别在术前及术后１、３、６、１２个月行角膜内皮检查及分析。结果：比较手术前后角膜内皮的数量、平均面积、最大面积和最小面积,穿孔眼及未穿孔眼差异无显著性,但内皮细胞面积两组都有扩大的趋势。结论：ＲＫ术后一年内无论微穿孔还是未穿孔眼的角膜内皮     

Nonsurgical management of extradural hematomas in children

With the advent of computerized tomography (CT), an increasing number of patients with only minimal neurological symptoms and no signs of brain herniation are found to harbor subacute or chronic extradural hematomas (EH's). The authors present the cases of 11 symptomatic but neurologically normal children with medium to large EH's managed by close observation. These EH's were discovered 4 hours to 6 days after injury; three were in the posterior fossa, seven over the frontoparietal convexity, and one in the temporal fossa. These clots were followed by serial CT scans. Nine children recovered without surgery from 4 to 18 days after injury, and all had evidence on CT of spontaneous clot resorption. Of these nine EH's, five clots displayed volume expansion from 5 to 16 days after injury before final resorption occurred. Expansion correlated with persistence or increase in symptoms, whereas resorption correlated with improvement. Two patients showed gradual uncal herniation on Days 6 and 8, respectively, presumably during the "expansile phase" of their clots. Both had emergency craniotomy and recovered without morbidity. It is hypothesized that the resorption dynamics of the subacute or chronic EH are similar to that of the chronic subdural hematoma, with predictable volume changes, and the outcome of each lesion depends on the interplay between the patient's intracranial pressure buffering capacity and the rate of volume change. If subtle signs of brain dysfunction are adopted to signal the failure of conservative treatment and the need for craniotomy, these patients may be safely, and many successfully, managed without surgery. Factors that influence outcome of medical treatment include the size, location, configuration, and the rapidity of accumulation of the clot, the presence of associated intradural lesions, the extracranial decompression of blood through skull diastases, and the age of the patient. These factors, the criteria for patient selection, and the indications for immediate operative intervention are discussed.     

蝙蝠葛中的新生物碱——蝙蝠葛新林碱

防已科植物蝙蝠葛(Menispermum daurioum DC.)的根茎,即北豆根,是一种重要的中药,具有清热解毒、消肿止痛等功效。已知含有近二十种生物碱,其中五种属双苄基四氢异喹啉类,即蝙蝠葛碱(dauricine,Ⅰ)、蝙蝠葛诺林碱(daurinoline,Ⅱ)、蝙蝠葛新诺林碱     

Dynamics of drug distribution. I. Role of the second and third curve moments.

Conventionally, the dynamics of distribution in the body is evaluated by the so-called distribution half-life (e.g., t1/2, alpha); but then the mean time of the distribution process is underestimated due to the influence of elimination. By contrast, information about the dynamics of distribution contained in drug disposition curves can be extracted by the second and third curve moments, parameters that are related to the variance (VDRT) and skewness (SDRT) of residence time distributions; whereas the equilibrium state characterized by the volume of distribution (Vss), is determined by the mean residence time (MDRT) or the first curve moment. The approach represents a general noncompartmental analysis that is independent of a detailed structural model or a particular disposition function. Two parameters are introduced to characterize the dynamics of drug distribution: (i) the degree of departure of the system from "well-mixed" behavior of instantaneous distribution equilibrium (related to VDRT) and (ii) the mean time until equilibration is achieved (mean equilibration time, MEQT), which additionally depends on SDRT. Both parameters are quantitative measures of the dynamics of distribution and display explicit physical significance in terms of distribution within the corresponding noneliminating system. It is further shown that the so-called "distribution phase" in biexponential disposition curves is related to a monoexponential mixing curve of its corresponding noneliminating system with an equilibration or mixing half-time, t1/2,M = t1/2,alpha (V beta/Vss*), where Vss* denotes the distribution volume of the noneliminating system. The results are applied to mixing and disposition curves measured for acetaminophen in liver-ligated and intact rats, respectively.