Combined use of erythrocyte zinc protoporphyrin and mean corpuscular volume in differentiation of thalassemia from iron deficiency anemia

Abstract: In a retrospective study the diagnostic value of erythrocyte zinc protoporphyrin (ZPP) measurement as a means of distinguishing iron deficiency anemia from thalassemia syndromes in patients with microcytosis was explored. ZPP values were increased in all patients with iron deficiency and in part of the patients with thalassemia. The combined measurement of erythrocyte mean corpuscular volume (MCV) and ZPP resulted in a correct classification of patients with iron deficiency and with thalassemia in more than 95%. The predictive value of this method is better than the results obtained by using formulae derived from red cell indices. In population screening programs for thalassemia syndromes, in which MCV determination is used as the initial test, the ZPP test is recommended as a second test, in order to discriminate between patients with microcytosis due to iron deficiency and patients with microcytosis due to thalassemia syndromes.     

A rigorous framework for diffusion tensor calculus.

In biological tissue, all eigenvalues of the diffusion tensor are assumed to be positive. Calculations in diffusion tensor MRI generally do not take into account this positive definiteness property of the tensor. Here, the space of positive definite tensors is used to construct a framework for diffusion tensor analysis. The method defines a distance function between a pair of tensors and the associated shortest path (geodesic) joining them. From this distance a method for computing tensor means, a new measure of anisotropy, and a method for tensor interpolation are derived. The method is illustrated using simulated and in vivo data.     

扩散加权成像对癫痫诊断价值的临床研究

目的　应用扩散加权成像(DWI)探讨磁共振成像(MRI)对癫痫的诊断价值。方法　64例包括对照组3 0例、颞叶癫痫组(TLE) 18例、颞叶外癫痫组(ELE) 16例应用DWI图测量并比较TLE患侧、对侧、对照组间海马的表观扩散系数(ADC)值差异。结果　对照组两侧ADC均值0 .88×10 -3 mm2 ·s-1,TLE组患侧ADC为(1.14±0 .3 0 )×10 -3 mm2 ·s-1,对侧为(0 .92±0 .2 8)×10 -3 mm2 ·s-1;ELE组两侧ADC均值(0 .90±0 .3 1)×10 -3 mm2 ·s-1,TLE组患侧与对照组及ELE组均有显著性差异(P =0 .0 0 6)。结论　DWIADC值的测量可用于对TLE致痫灶定侧。     

磁共振扩散加权成像在肝脏占位性病变诊断中的应用

目的探讨MR扩散加权成像(DW I)及ADC值对肝脏占位性病变的诊断价值。方法原发性肝细胞癌36例,转移瘤15例,肝血管瘤33例,肝囊肿12例进行MR I平扫及DW I,拟合出ADC图,选取病灶感兴趣区,测出ADC值,进行量化分析。结果肝脏占位性病变的平均ADC值如下:肝囊肿(2.90±0.68)×10-3mm2/s,血管瘤(2.01±0.53)×10-3mm2/s,转移瘤(1.57±0.42)×10-3mm2/s,原发性肝细胞癌(1.20±0.32)×10-3mm2/s。肝脏良性病变的ADC值明显高于恶性肿瘤,并有显著性差异(P<0.05)。结论通过对肝脏不同病变的ADC值进行量化分析,能为肝脏占位性病变的定性诊断提供重要依据。     

良性前列腺增生的ADC值定量分析

目的运用MR扩散加权成像对不同类型良性前列腺增生的ADC值进行定量分析,并与前列腺癌ADC值进行比较。方法17例行经尿道前列腺电切术的良性前列腺增生患者,在术前3个月内均进行了前列腺DWI检查。采用单次激发EPI序列,b值为0 s/mm2和800 s/mm2,电切术后对标本进行了组织学分类,将增生组织分为腺体型增生和间质型增生,并分别测量其ADC值。另外还选取了15例穿刺活检证实的前列腺癌病人,测量其癌区的ADC值。对所得3组数值进行统计学分析。结果腺体型增生、间质型增生、前列腺癌的ADC值分别为(1.80±0.20)×10-3mm2/s、(1.56±0.18)×10-3mm2/s、(1.27±0.21)×10-3mm2/s,3组间具有统计学差异(F=47.366,P<0.01,one-way ANOVA),两两比较也具有统计学意义(P值均<0.01)。腺体增生和间质增生间有62%的ADC值重叠,腺体增生和癌之间有22%的ADC值重叠,间质增生与癌之间有57%的ADC值重叠。结论用ADC值可以定量评价不同类型的良性前列腺增生,增生与前列腺癌的ADC值有统计学差异,但存在部分重叠,以间质型增生重叠较明显。     

H_1 and H_2 receptors in the locus ceruleus are involved in the intracere-broventricular histamine-induced carotid sinus baroreceptor reflex reset-ting in rats

1 Introduction Central histamine (HA) has been regarded as one of the important neurotransmitters or neuromodulators[1]. Brain HA keeps in close touch with the changes of cardio- vascular activities[1-3]. Carotid sinus baroreceptor reflex (CSR) with negative feedback regulation is a predominant approach to maintaining the spontaneous and simultaneous blood pressure homeostasis in mammal. It has been evi- denced that intracerebroventricular (i.c.v.) administration of HA can bring CSR reset…     

MR灌注加权成像在兔VX2软组织肿瘤中应用的实验研究

目的：初步评价MR灌注加权成像方法在软组织肿瘤中的应用价值。方法：10只新西兰大白兔，在其一侧大腿近段注射VX2肿瘤组织悬液0．1ml，分别于肿瘤组织接种后第14天、21天行MR平扫和灌注扫描，扫描图像经AW4．0工作站处理，计算灌注参数(包括相对血流量rBF、相对血容量rBF和平均通过时间MTT)并分析灌注曲线图。随后将荷瘤兔处死并取出肿瘤，用10％福尔马林固定，于光学显微镜下观察肿瘤组织的结构特点。结果：所有兔大腿VX2肿瘤组织的rBF、rBV值明显高于正常肌肉组织，而MTT值则低于正常肌肉组织。结论：MR灌注加权成像是一种安全、简便且较准确的半定量评估软组织肿瘤性病变血流灌注状态的功能成像方法，它可以为肿瘤治疗方案的制定、治疗后的疗效监测以及预后判断提供重要的参考依据。     

Effects of, and corrections for, cross-term interactions in Q-space MRI.

The present study assesses the effects of cross-term interactions between diffusion and imaging gradients in magnetic resonance imaging q-space analysis, and corrects for those effects for both spin echo and stimulated echo diffusion-weighted sequences. These corrections are demonstrated experimentally in unrestricted media for water and theoretically by simulating the case of restricted diffusion in a sphere. By correcting for the cross-term interactions, large imaging gradients can be used without compromising the results. Ignoring cross-term interactions could lead to a misunderstanding of the q-space analysis; for instance, the microstructural size of the sample could be overestimated, or isotropic media could be misinterpreted as being anisotropic.     

Mortality of urban firefighters in alberta, 1927–1987

The mortality experience of firefighters has been an active topic of investigation. Collateral toxicological evidence suggests that certain causes of death are likely to be associated with firefighting: lung cancer, heart disease, and obstructive pulmonary disease. To date there has not been a clear and consistent demonstration of excess risk due to occupational exposure for these outcomes, but certain other cancers, including genitourinary, colon and rectum, and leukemias, lymphomas, and myeloma, appear to be consistently elevated. A major unproven hypothesis is that risk increased following the introduction, in the 1950s, of combustible plastic furnishing and building materials known to generate toxic combustion products. Mortality by cause of death was examined for two cohorts totalling 3,328 firefighters active from 1927 to 1987 in Edmonton and Calgary, the two major urban centers in the province of Alberta, Canada, examining associations with cohort (before and after the 1950s) and years of service weighted by exposure opportunity. The study attained 96% follow-up of vital status and over 64,983 person-years of observation, yielding 370 deaths. Mortality from all causes was close to the expected standardized mortality ratio (96; 95% confidence limits (CL) 87, 107) as was that for heart disease (110; 95% CL 92, 131), and neither was statistically significant at the p < 0.05 level (N.S.). Excesses were observed for all malignant neoplasms (127; 95% CL 102, 155, p < 0.05) and for cancer of lung (142; 95% CL 91, 211, N.S.), bladder (315; 95% CL 86, 808, N.S.), kidney and ureter (414; 95% CL 166, 853, p < 0.05), colon and rectum (161; 95% CL 88, 271, N.S.), pancreas (155; 95% CL 50, 362, N.S.) and leukemia, lymphoma, and myeloma (127; 95% CL 233, N.S.); obstructive pulmonary diseases (157; 95% CL 79, 281, N.S.). Fire-related causes showed a marked excess (486; 95% CL 233, 895, p < 0.01), but external causes overall showed a marked excess (486; 95% CL 233, 895, p < 0.01), but external causes overall showed a significant deficit (66; 95% CL 49, 87, p < 0.05). The lung cancer excess was confined to Edmonton; there was no consistent association with duration of employment, exposure opportunity, or cohort of entry (before or after the 1950s) except that the highest risk was observed among Edmonton firefighters with over 35 weighted years. The excess of cancers of the urinary tract was observed mostly among firefighters entering service after 1950, appeared to increase with length of service and exposure opportunity, and was observed in both cities. An occupational association with heart disease and chronic pulmonary disease is not supported in this study on this population. An effect on lung cancer is not obvious, but may be present in the highest exposure group; a weak effect for lung cancer confounded by stronger effects cannot be ruled out. Associations of firefighting with cancers at genitourinary sites and with fire-related injury are strongly suggested in this population. © 1993 Wiley-Liss, Inc.