An Unexpected Change in DXA Calibration not Detected by Routine Quality Control Checks

Since its commercial introduction a decade ago, the technique of dual-energy X-ray absorptiometry (DXA) has been widely recognized as a useful and sensitive method of measuring changes in bone mineral density (BMD) at selected sites in the skeleton such as the spine and proximal femur. Because of their high precision and stable calibration, DXA scanners are frequently used in clinical trials to evaluate new treatments for osteoporosis. Quality assurance procedures based on regular scanning of phantoms are widely adopted in such trials, and continuity of the phantom BMD measurements is generally believed to ensure continuity in the in-vivo calibration. We report a change in calibration of a DXA scanner that occurred during a clinical trial where the calibration shift was different for the spine and femur sites and was not predicted or explained by the standard quality control procedures using phantoms. However, we show that provided patients enrolled in studies are thoroughly randomized and the statistical analysis is confined to the differences between the treated and control groups, then the effects of such calibration shifts on conclusions regarding the efficacy of treatment are considerably smaller than the random statistical errors. Received: 12 February 1998 / Accepted: 20 May 1998     

Anordrin对人体子宫内膜超微结构的影响

本文报道了口服Anordrin一个周期的妇女子宫内膜腺体细胞和基质细胞超微结构的变化。结果指出,服药2—3天后两类细胞的线粒体都发生肿胀,这可能是抑制腺体细胞发育和基质细胞转化的重要原因。溶酶体的提早出现又表明Anordrin 有促使子宫内膜早衰的作用,这可能与黄体功能不足有关,另从Anordrin 对离体培养子宫内膜的作用看,也不能排除Anordrin 对细胞有直接作用。     

The Biosynthesis of Melanin-Concentrating Hormone in Trout Kept Under Different Conditions of Background Colour and Stress, as Determined by an in vitro Method

The aim of this study was to develop a method to monitor the synthetic activity of neurons which secrete the neurohypophysial melanin-concentrating hormone (MCH), a hormone implicated in two separate physiological roles in fish-pigmentary regulation and the response to stress. Trout hypothalamic fragments, containing the MCH neuronal cell bodies, were incubated in vitro in a medium including [(35) S]methionine. Labelled MCH-related products were separated by immunoprecipitation. Gel electrophoresis showed that radioactive methionine was incorporated into MCH precursors and into mature MCH, much as in vivo. Thus, de novo hormone synthesis continues in vitro. Trout reared at a fish-farm and adapted to black or white tanks for 39 days displayed nearly a 2-fold difference in their rate of methionine incorporation. Transferring fish from a black to a white background also doubled the rate of incorporation within 7 days and this rate increased only very slightly during the following 3 weeks. The rate of methionine incorporation by tissue from trout reared in black tanks was very depressed, and 4-fold lower than that of fish reared in white tanks, suggesting that very long-term adaptation to one or other background has increasingly marked effects on the activity and perhaps the number of synthetically active neurons. Stress also influenced the rate of methionine incorporation: a mild daily stress was stimulatory but more frequent stress had an inhibitory effect in many cases. The effects of daily dexamethasone administration were inconclusive. It is suggested that these differences in methionine incorporation reflect the relative rates of MCH synthesis in vivo, and that the method is useful to investigate conditions which modulate the biosynthesis of MCH in the trout.     

Permeability changes of Ehrlich mouse ascites tumor cells induced by a cytotoxin from Pseudomonas aeruginosa

Summary Ehrlich ascites tumor cells from mice were damaged during in vitro incubation with a cytotoxin from Pseudomonas aeruginosa at concentrations of>1 g/ml. After a short time the cells started to lose potassium whereas their sodium content increased. When the protein concentration of the incubation medium was adjusted to the protein concentration inside the cells, swelling and release of glucose-6-phosphate dehydrogenase was avoided. However, lysis of the cells still took place.Preincubation of cells with tetrodotoxin, 4-aminopyridine or tetraethylammonium did not influence damage to the cells. The cells showed a steep increase in toxin response between 17° and 27°C ranging from insensitivity to full sensitivity.An increase in electrical conductance was measured during incubation of cholesterol bilayer membranes with a cytotoxin concentration of 1 g/ml. The conductance was increased by a factor of ten within 30 min at 25°C which indicates the involvement of membrane lipids in the cytotoxin action.Part of this study has been presented at the Joint Meeting of the Scandinavian and German Pharmacological Societies, Lübeck (Grieshaber and Lutz 1980)     

Diazepam metabolism in human foetal and adult liver

Summary Diazepam was metabolized by human foetal liver microsomes to N-desmethyldiazepam and N-methyloxazepam as early as the 13th week of gestation. The metabolic activity was lower than that of microsomes from adult human liver. Diazepam was shown mainly to be hydroxylated to N-methyloxazepam at substrate concentrations higher than 0.1 mM. Diazepam levels above 1.0 mM were inhibitory to the overall metabolic reaction. SKF 525-A inhibited diazepam metabolism by foetal liver microsomes at a concentration of 0.1 mM. The addition of diazepam to foetal and adult human liver microsomes resulted in a type II spectral change. Its inhibition by carbon monoxide indicated that biotransformation of diazepam was performed by the cytochrome P-450-linked mono-oxygenase system.     

Dietary factors and cancers of breast, endometrium, and ovary: Strategies for modifying fat intake in African American women

Modification of dietary fat and fiber could help prevent cancers of the breast, endometrium, and ovary that are prevalent in African-American women. Dietary intervention programs aimed at reducing fat intake have had mixed results in this population. The transtheoretic model is proposed for achieving dietary change. Strategies for changing health behaviors in African-American women include heightening sensitivity to cultural values among health educators and the use of multiple strategies to reinforce messages. To stimulate healthier eating, it is important to incorporate the distinct habitual eating patterns into innovative intervention methods, using effective behavioral change methods. (Am J Obstet Gynecol 1997;176:S255-64.)     

Serum levels of C3 and Factors I and B in minimal change disease

Abstract Background: Relapses are an important problem in minimal change disease, which accounts for most of the cases of childhood nephrotic syndrome. Because of defects in the humoral immune system, patients are predisposed to infection in nephrotic syndrome and infection is the most important complication that determines mortality and morbidity.
Methods: In this study, serum levels of Factors I and B and C3 were studied to evaluate the relationships between nephrotic syndrome and infection in 17 children with nephrotic syndrome (24–96 months of age) and 10 healthy children (27–84 months of age).
Results: Serum levels of Factors I and B were found to be lowered in the active disease group compared with the control group. These values were lowest for the infection group. Although it was observed that these values increased with steroid treatment, they did not reach normal levels. The parameters in remission were not different from the parameters in the control subjects. The serum level of C3 was found to be high during the active disease state and returned to normal levels during remission.
Conclusions: The patients with active minimal change disease had infections such as peritonitis, septicemia and urinary tract infection because of low concentrations of Factors I and B in their sera.     

糖尿病并心电图缺血性ST-T改变相关因素分析

目的探讨糖尿病人发生心电图缺血性ST-T改变的发生率及相关影响因素。方法对比分析糖尿病人在不同危险因素(高血压、高脂血症、病程5年上下、同时合并有高血压和高脂血症)的情况下,发生心电图缺血性ST-T改变的发生率。结果合并高血压时发生率为64.5%,合并高脂血症时发生率为56.3%,同时合并高血压和高脂血症时发生率为66.7%(且呈广泛ST-T改变),病程>5年的发生率为49.3%,均明显高于不伴高血压、高血脂及病程<5年者,均P<0.05。结论糖尿病合并高血压、高脂血症、同时有高血压和高脂血症及病程>5年的发生心肌缺血性ST-T改变的危险性明显增加。糖尿病如合并其他危险因素存在,应在控制血糖的同时尽早对其他危险因素进行干预。     

Age at onset of schizophrenia: gender differences and influence of temporal socioeconomic change

This study was undertaken to examine whether males develop schizophrenia at a younger age than females, and whether temporal socioeconomic change affects the age at onset of schizophrenia. The subjects were 848 ICD-9 schizophrenics who were admitted to Nihon University Hospital, Tokyo, Japan, during the period of 1955-64 (n = 468 (214 males and 254 females), group A) or during the period of 1982-91 (n = 380 (220 males and 160 females). group B). Schizophrenic males showed an earlier age at onset than schizophrenic females. However, the mean age at onset of schizophrenia did not differ significantly between group A and group B. These results indicate that the gender difference in age at onset of schizophrenia has not been influenced by temporal socioeconomic change.     

系统性红斑狼疮患者的症状群及其网络分析

目的 描述系统性红斑狼疮患者症状群的构成,并运用网络分析探索群内症状之间的关系,为症状管理提供依据。方法 采取便利抽样原则选取201例系统性红斑狼疮患者为研究对象。采用一般资料调查表、系统性红斑狼疮症状清单对患者进行调查。症状群的提取采用探索性因子分析,以JASP软件绘制网络分析图及各症状中心指标图,分析群内症状之间的关系。结果 系统性红斑狼疮患者疲劳的发生率最高(64.7%),共提取5个症状群：疲劳相关症状群、体质量增加相关症状群、瘙痒-疼痛相关症状群、皮肤改变症状群、身体形象症状群。经过网络分析,对太阳光过敏在所有集群中的强度和紧密度最高,情绪改变的中介度最高。结论 系统性红斑狼疮患者存在症状群,各症状的影响强度不同。临床医护人员需密切关注患者症状,通过改善核心症状来改变群内与之相关的其他症状,进一步提高患者的生活质量。