Accuracy of gated equilibrium radioventriculography in measuring left ventricular function in dogs

To assess the precision of gated equilibrium radioventriculography in measuring changes in left ventricular stroke volume (LVSV), we studied five dogs each with a chronically implanted electromagnetic flowmeter on the ascending aorta. Per cent changes in left ventricular stroke counts (LVSC) were compared to those in LVSV following acute changes induced by positive end respiratory pressure. We have compared LVSCs calculated in five different ways: (1) Manual outlining of LV region of interest (LVROI), either single fixed enddiastolic (ED) ROI or ED and endsystolic (ES) ROIs with the aid of functional images (first harmonic of Fourier analysis); (2-5) automatic outlining of LV ROI (the algorithm generated 30 profiles on which the maximum of second derivative delineated the LV edges) was performed either on ED image or both ED and ES images. For these four methods a crescent-shaped ROI for background correction was manually drawn at the border of the LV ROI. The fifth method used an automatically drawn single fixed LVED ROI with interpolative background substraction (IBS) between LV and RV edges. LVSC changes, calculated with the IBS method correlated better with LVSV changes than the other four methods. Thus assessment of small LVSC changes is highly processing-dependent.     

高敏肌钙蛋白T动态变化在晚时间窗内进行血管内治疗的急性缺血性脑卒中患者中的预测价值

目的探讨高敏肌钙蛋白T（high-sensitivity cardiac troponin T，hs-cTnT）动态变化与晚时间窗内接受机械取栓治疗的前循环大血管闭塞型急性缺血性脑卒中患者不良预后的相关性。 方法共纳入161例患者，分别于入院时和24 h测量血清hs-cTnT。hs-cTnT升高定义为大于14 ng/L；hs-cTnT动态变化定义为两次测量值上升或下降超过20%且至少有一次大于14 ng/L。评价hs-cTnT动态变化与3个月时不良预后的相关性；比较入院时hs-cTnT升高与hs-cTnT动态变化预测3个月时不良预后的接收者操作特征（receiver-operating characteristic，ROC）曲线下面积（areas under the ROC curve，AUC）。 结果67（41.6%）例患者发生hs-cTnT动态变化。多因素分析显示，hs-cTnT升高（P = 0.014，P = 0.038）和hs-cTnT动态变化（P < 0.001，P < 0.001）分别是不良预后和死亡的独立预测因素。AUC比较显示hs-cTnT动态变化对不良预后（AUC 0.765 vs 0.689，P = 0.043）和死亡（AUC 0.818 vs 0.687，P = 0.008）的预测价值要显著优于入院时hs-cTnT升高。 结论hs-cTnT动态变化是晚时间窗进行血管内治疗的急性颅内大血管闭塞性脑卒中患者3个月时不良预后和死亡的独立预测因素。hs-cTnT动态变化对不良预后的预测价值要显著优于入院时hs-cTnT升高。     

Serum proteins in rats after combined neutron and gamma irradiation

Quantitative changes of some selected serum proteins in rats irradiated with a single dose of 2 Gy neutrons were compared with protein changes in rats irradiated with an equal single neutron dose and subsequent continuous gamma irradiation using daily dose rate of 0.574 Gy up to the total dose of 6 Gy. On the basis of the values obtained from the diagrams of two-dimensional immunoelectrophoresis it was found that both irradiations entailed approximately equal quantitative changes of the serum concentrations of the proteins followed. The differences found concerned time intervals of the adjustment of the changes produced. After neutron irradiation reparation of the serum albumin occurred on 14th day, of A1-globulin concentrations on 28th day and of haptoglobin on 90th day, yet after combined neutron and gamma irradiation reparation of the changes in albumin on 15th and A1-globulin occurred on 40th day and in haptoglobin only on 100th day after neutron irradiation.     

Phenomenology and mechanisms of changes in the basic functions of the human body in weightlessness

In the course of the space era the duration of manned flights increased from 108 minutes to 326 days. During the flights a large number of biomedical investigations were carried out to study the phenomenology and mechanisms of space flight effects on the human body. It was demonstrated that exposure to microgravity produced most significant changes. Short-term effects include space adaptation syndrome changes associated with fluid shifts and changes in movement coordination. Long-term effects involve various changes in the musculoskeletal system, cardiovascular system, metabolism and its regulation, endocrine system, blood and immunity system. This paper describes symptom-complexes that are consistently observed in space flight, discusses mechanisms of changes and adaptation of vital physiological systems, and outlines main periods of changes during and after flight.     

腕关节X线侧位三角形阴影改变对腕骨脱位的诊断价值

目的 探讨腕关节侧位三角形阴影的改变对腕骨脱位的诊断价值.方法 68例腕骨脱位患者均摄有腕关节正侧位片,通过对腕关节正常影像学表现及腕骨脱位的影像学资料进行观察分析,对比腕骨脱位患者腕关节侧位三角形阴影的改变.结果 68例腕骨脱位患者中,腕关节侧位三角形阴影有改变65例,占95.59％,无改变3例,占4.41％.其中单纯腕骨脱位17例,腕关节侧位三角形阴影有改变15例,无改变2例;腕骨周围脱位32例,腕关节侧位三角形阴影有改变31例,无改变1例;经腕骨腕骨脱位或腕骨周围脱位19例,腕关节侧位三角形阴影均发生改变.结论 腕关节侧位三角形阴影的改变对绝大多数腕骨脱位的诊断有重要价值,对腕骨侧向脱位的诊断无意义.     

维拉帕米对烧伤大鼠心肌保护作用的实验研究

 目的了解烧伤后心肌细胞病理变化特点及维拉帕米对心肌的保护作用.方法采用光镜及透射电子显微镜观察烧伤大鼠心肌病理变化.结果烧伤后心肌病理改变以单纯烧伤组程度最重,补液组次之,维拉帕米治疗组最轻.结论烧伤可导致心肌组织学及超微结构发生明显改变,是烧伤后心功能障碍的形态学基础,维拉帕米可明显减轻烧伤后心肌细胞病理变化程度,对心肌有一定的保护作用.     

Skeletal changes in tuberous sclerosis

This paper is based on the skeletal changes which were found in six cases with confirmed tuberous sclerosis. The bone changes of this rare condition are summarised. The differential diagnosis is discussed.     

The value of MR imaging in monitoring the effect of chemotherapy on bone sarcomas

We studied the value of MR imaging in monitoring the response of Ewing sarcoma and osteosarcoma to chemotherapy. Relative signal-intensity changes on MR images in the course of chemotherapy were compared with changes in tumor volume and histopathologic findings. MR scans (T1- and T2-weighted spin-echo images) were obtained in 20 patients with bone sarcoma. The first MR scan was obtained before the administration of chemotherapy in all patients. The follow-up scan was obtained in the course of treatment, before surgery. Tumor-volume and signal-intensity measurements of the intra- and extraosseous components of the tumor were analyzed. In 17 patients, histopathologic findings of the resected tumor were available for comparison with the MR images. In 12 of 17 patients there was complete agreement between changes in tumor volume, changes in the signal intensity of the extraosseous tumor component on T2-weighted images, and histopathology. In another four cases, changes in signal intensity correlated either with histopathology or with changes in tumor volume. In one patient with a pathologic fracture, no such correlation existed. A significant correlation was found between changes in signal intensities and pathologic response (r = .57, p = .02), as well as between changes in tumor volume and pathologic response (r = .53, p = .03). No correlation could be found between changes in signal intensity of the intraosseous tumor component and changes in tumor volume or histopathology. We conclude that the signal intensity of the extraosseous component of bone sarcomas on T2-weighted MR images in addition to changes in tumor volume may be useful in evaluating response to chemotherapy.     

Na2ATP对尾部悬吊大鼠比目鱼肌梭内、外肌纤维MHC表达的影响

目的 探讨三磷酸腺苷二钠盐（Na2ATP）对尾部悬吊大鼠比目鱼肌（SOL）梭内、外肌纤维肌球蛋白重链（MHC）表达的影响。方法 采用大鼠尾部悬吊法建立废用模型，用免疫组织化学技术，观察Na2ATP注射液对大鼠比目鱼肌（SOL）梭内、外肌纤维MHC表达的影响。结果 尾部悬吊14d后大鼠比目鱼肌梭内、外肌纤维中快缩型MHC的表达均有所增加，而在尾吊期间注射Na2ATP后比目鱼肌梭内、外肌快缩型MHC表达没有明显变化。结论 Na2ATP注射液对尾部悬吊大鼠比目鱼肌梭内、外肌纤维MHC表型转化有明显的对抗作用。     

Direct radiographic magnification in bone infections

An experimental model of bacterial osteomyelitis was used to investigate the correlation of direct radiographic magnification and histopathologic changes in the femora of rabbits. The histopathologic changes demonstrated a severe chronic state of osteomyelitis. The extent of radiographic changes was more clearly recognizable with direct radiological enlargement (up to 15-fold) than on normal radiographs: this applied to destruction of marrow and cortical bone, formation of sequestra, and (frequently) extraosseous extension. Histopathologic findings were in agreement with the changes revealed by direct radiographic enlargement.     

Adaptations in interlimb and intralimb coordination to asymmetrical loading in human walking

The purpose of this study was to examine both the intralimb (within a limb) and interlimb (between the right and left limbs) adaptations that occur in response to a unilaterally applied leg load as subjects walked at their preferred walking speed. It was hypothesized that this adaptation would alter interlimb coordination while intralimb coordination remained invariant. Subjects (n = 12) were required to walk on a treadmill at preferred walking speed. Bilateral 3-D kinematic data were collected while a load placed on the leg was increased. Gait adaptations to leg-loading were assessed through changes in coordination patterns between specific limb couplings. Continuous relative phase (CRP) was used to evaluate changes in limb coordination under each experimental load condition compared to a no load baseline condition. Both changes in magnitude of CRP (root-mean-square (RMS) analysis) as well as temporal changes in CRP across the stride cycle (cross-correlation) were assessed. Cross-Correlation values changed with load for all interlimb couplings assessed suggesting alterations in interlimb coordination across the stride cycle. CRP cross-correlation values were close to 1.0 in all the intralimb couplings examined, showing a relative invariance in intralimb coordination. Coordination changes in RMS were also observed for the interlimb couplings. RMS changes were also observed in the intralimb couplings on the loaded side. It appears that gait adaptations to a unilaterally applied leg load appear both at the intralimb and interlimb level. However, the majority of changes did appear at the interlimb level, where CRP as assessed through both cross-correlation and RMS measures changed. This study supports previous results that suggested a tighter coupling exists at the intralimb level, leaving the majority of gait adaptations to occur at the interlimb level. The observed adaptation in differences between interlimb and intralimb coordination may provide insight into gait adaptations in pathological gait.     

4D deformation modeling of cortical disease progression in Alzheimer's dementia.

This work describes the development of a model of cerebral atrophic changes associated with the progression of Alzheimer's disease (AD). Linear registration, region-of-interest analysis, and voxel-based morphometry methods have all been employed to elucidate the changes observed at discrete intervals during a disease process. In addition to describing the nature of the changes, modeling disease-related changes via deformations can also provide information on temporal characteristics. In order to continuously model changes associated with AD, deformation maps from 21 patients were averaged across a novel z-score disease progression dimension based on Mini Mental State Examination (MMSE) scores. The resulting deformation maps are presented via three metrics: local volume loss (atrophy), volume (CSF) increase, and translation (interpreted as representing collapse of cortical structures). Inspection of the maps revealed significant perturbations in the deformation fields corresponding to the entorhinal cortex (EC) and hippocampus, orbitofrontal and parietal cortex, and regions surrounding the sulci and ventricular spaces, with earlier changes predominantly lateralized to the left hemisphere. These changes are consistent with results from post-mortem studies of AD.     

Physical activity in leisure-time is not associated with 10-year changes in waist circumference

To examine whether physical activity (PA) is associated with changes in waist circumference (WC), and changes in WC given changes in body mass index (BMI). Longitudinal population-based study including 2026 men and 2782 women aged 21-81 years. Subjects were examined in 1991-1993 (baseline) and 2001-2003 (follow up), where height, weight and WC were measured. Information about overall PA in leisure-time (LTPA), walking, biking and sports activity was collected with self-administrated questionnaires at baseline. Outcomes were changes in WC and changes in WC given changes in BMI between baseline and follow up. The median increase in WC was 3.0 cm in men and 3.5 cm in women during follow-up, and with a considerable inter-individual variation. LTPA, walking and biking were not significantly associated with the outcomes. Inverse associations between sports activity and the outcomes were observed in both sexes, and these were significant in some analyses. Associations were not altered by adjustment for confounders or by exclusions of subjects with diseases and/or treatment by obesity-inducing medication. This study suggests that LTPA, walking and biking have no appreciable effects on changes in WC or changes in WC given changes in BMI, whereas sports activity may have small preventive effects.     

脑电图在小鼠氧惊厥研究中的应用

目的 观察小鼠氧惊厥及惊厥后脑电图的改变。方法 小鼠头部预先埋置电极，进行舱内高压氧（HBO）暴露，动态观察记录氧惊厥小鼠脑电改变以及暴露后脑电恢复情况。结果 小鼠埋置电极3～5d后脑电改变恢复正常，舱内HBO暴露致氧惊厥时脑电图发生类似癫痫大发作时的痫波变化，并在氧暴露撤离后7d左右脑电图改变恢复正常。结论 脑电图记录在小鼠氧惊厥研究中是一种可行、客观和稳定的方法。     

Reversible and non-reversible enlargement of cerebrospinal fluid spaces in anorexia nervosa

Summary Brain CT studies of 35 patients with anorexia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerebrospinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa.     

Age-related changes in upper body adaptation to walking speed in human locomotion

Assessments of changes in gait stability due to aging and disease are predominantly based on lower extremity kinematic and kinetic data. These gait changes are also often based on comparisons at preferred speed only. The purpose of this experiment was to: (1) examine age-related changes in range of motion and coordination of segments of the upper body during locomotion; and (2) investigate the effects of a systematic walking velocity manipulation on rotational motion and coordination. Participants (n=30) walked on a motor driven treadmill at speeds ranging from 0.2 to 1.8m/s and were divided into three groups with mean ages of 23.3, 49.3 and 72.6 years, respectively. Seven high-speed infrared cameras were used to record three-dimensional kinematics of the pelvis, trunk and head. Dependent variables were amplitude of segmental and joint rotations, as well as relative phase to assess coordination between segments. Although no differences in stride parameters were found between the groups, age-related changes in movement amplitude in response to speed manipulations were observed for all segments and joints. Pelvic rotations in sagittal, frontal and transverse planes of motion were systematically reduced with age. Older individuals showed reduced trunk flexion-extension in the sagittal plane and increased trunk axial rotation in the transverse plane. Coordination analysis showed reduced compensatory movement between pelvis and trunk in older individuals. These findings support the importance of systematic manipulation of walking velocity and three-dimensional upper body kinematics in assessing age-related changes in locomotor stability and adaptability.     

Regional magnetization transfer ratio changes in mild cognitive impairment.

Reduction in temporal lobe volume is consistently found in dementia of Alzheimer's type (DAT). However, due to the lack of a consistent association between brain volume and cognitive decline in mild cognitive impairment (MCI), volumetric measures are not a reliable predictor for the progression of the disease. In our study, we hypothesized that changes in the magnetization transfer ratio (MTR) may reflect underlying brain pathology in the absence of quantifiable volumetric changes. Such a measure may be used as a predictor for abnormal cognitive decline in elderly subjects. The study was carried out on 15 normal elderly controls, 11 subjects with DAT, and 12 subjects with MCI. We used MTRs with magnetic resonance imaging (MRI) to detect tissue changes in the four lobes of each hemisphere, and compared that to the volumetric changes in the same regions. Our results indicate that the MTR of both temporal lobes is significantly reduced in subjects with MCI in the absence of significant volumetric changes. In comparison, DAT subjects have significantly reduced temporal lobe volumes and MTR. We conclude that changes in MTR have the potential to mark the progression of MCI to DAT, before volumetric changes are detected on conventional MRI scans.     

Measurement of left ventricular dimensions and function in patients with dilated cardiomyopathy

Studies on medical therapy in heart failure are focused on changes of left ventricular (LV) dimensions and function. These changes may be small, requiring a large study group. We measured LV parameters (LV volumes, LV ejection fraction (LV-EF), and left ventricular mass (LVM)) with two-dimensional echocardiography (2D-echo) and magnetic resonance imaging (MRI) in 50 patients. Based on the difference between the measurements, we determined the variance of the results and calculated the sample sizes needed to detect changes of baseline values. For the calculated and measured parameters we found significant differences between the two techniques: LV-EF and LVM were higher in 2D-echo, and LV dimensions were comparable. The sample size to detect relevant changes from baseline with MRI was significantly (P < 0.01) smaller than in 2D-echo. We conclude that MRI is superior in clinical studies on left ventricular dimensional and functional changes, since measurements are more reproducible and the required sample size is substantially smaller, thereby reducing costs.     

Asymmetrical changes in asbestos-related disease

The radiographic changes in 200 patients with known or suspected asbestos exposure were reviewed. Pleural plaques or thickening, with or without calcification, occurred solely or predominantly on the left side in 90, on the right side in 32, and equally bilaterally in 44. Asymmetry is common in asbestos-related disease, and apparently unilateral findings should prompt a search for more subtle changes elsewhere.     

Radiographic appearance of the sternomanubrial joint in arthritis and related conditions

The sternomanubrial joint (SMJ) was evaluated on the lateral chest radiograph in 177 patients with rheumatic disease and 69 non-rheumatic controls. Abnormalities were categorized as inflammatory changes, proliferative changes, or bone fusion. Patients with rheumatoid arthritis, psoriatic arthritis, or gout were found to have an increased incidence of inflammatory changes. Rheumatoid variants predisposed to early fusion of the SMJ. Patients with diffuse idiopathic skeletal hyperostosis (DISH) exhibited massive and unique hyperostotic changes.