Evaluation of intraaxial enhancing brain tumors on magnetic resonance imaging: intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for visualization and assessment, and implications for surgical intervention

OBJECT: The goal in this article was to compare 0.1 mmol/kg doses of gadobenate dimeglumine (Gd-BOPTA) and gadopentetate dimeglumine, also known as gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), for enhanced magnetic resonance (MR) imaging of intraaxial brain tumors. METHODS: Eighty-four patients with either intraaxial glioma (47 patients) or metastasis (37 patients) underwent two MR imaging examinations at 1.5 tesla, one with Gd-BOPTA as the contrast agent and the other with Gd-DTPA. The interval between fully randomized contrast medium administrations was 2 to 7 days. The T1-weighted spin echo and T2-weighted fast spin echo images were acquired before administration of contrast agents and T1-weighted spin echo images were obtained after the agents were administered. Acquisition parameters and postinjection acquisition times were identical for the two examinations in each patient. Three experienced readers working in a fully blinded fashion independently evaluated all images for degree and quality of available information (lesion contrast enhancement, lesion border delineation, definition of disease extent, visualization of the lesion's internal structures, global diagnostic preference) and quantitative enhancement (that is, the extent of lesion enhancement after contrast agent administration compared with that seen before its administration [hereafter referred to as percent enhancement], lesion/brain ratio, and contrast/noise ratio). Differences were tested with the Wilcoxon signed-rank test. Reader agreement was assessed using kappa statistics. Significantly better diagnostic information/imaging performance (p < 0.0001, all readers) was obtained with Gd-BOPTA for all visualization end points. Global preference for images obtained with Gd-BOPTA was expressed for 42 (50%), 52 (61.9%), and 56 (66.7%) of 84 patients (readers 1, 2, and 3, respectively) compared with images obtained with Gd-DTPA contrast in four (4.8%), six (7.1%), and three (3.6%) of 84 patients. Similar differences were noted for all other visualization end points. Significantly greater quantitative contrast enhancement (p < 0.04) was noted after administration of Gd-BOPTA. Reader agreement was good (kappa > 0.4). CONCLUSIONS: Lesion visualization, delineation, definition, and contrast enhancement are significantly better after administration of 0.1 mmol/kg Gd-BOPTA, potentially allowing better surgical planning and follow up and improved disease management.     

Influence of PDE5 inhibitor on MRI measurement of clitoral volume response in women with FSAD: a feasibility study of a potential technique for evaluating drug response

The purpose of this study was to determine if magnetic resonance imaging (MRI) could quantify a difference in clitoral response following administration of a vasoactive medication, in 12 women with female sexual arousal disorder (FSAD). Subjects were entered into a double-blind, randomized two-way crossover study of sildenafil 50 mg vs placebo administered 1 h prior to genital MRI. Each subject underwent two MR studies, performed while subjects viewed alternating segments of nonerotic and erotic video. MR images were analyzed for change in clitoral volume during each session. The mean change in clitoral volume for the entire group was higher in the sildenafil MRI session (1282 mm(3)) compared with placebo (849 mm(3)) but did not reach statistical significance (P=0.064). Comparison using analysis of variance between the two sessions for each individual subject revealed a significant increase in clitoral volume following sildenafil compared with placebo in 6 of 12 subjects, no significant change in either imaging session in three subjects and in three subjects, there was a robust clitoral response in both MR sessions. In conclusion, MR measurements of clitoral volume can provide an objective measure of engorgement change following a vasoactive medication in women with FSAD.     

Epidemiologic and ultrasonographic study of echinococcosis in a community in the state of Mexico

No epidemiologic study for cystic echinococcosis in México has yet been described. The objective of this work was to determine the prevalence and distribution of human echinococcosis in a community of the state of México and its probable risk factors. A cross-sectional study was performed; household census was used to randomly select houses. The larval stage of Echinococcus was searched by ultrasound in liver, spleen, and kidney. A questionnaire was used for the investigation of risk factors. The study was performed with 401 persons, 64% were female. The prevalence of echinococcosis was 0.75%. Cases were distributed in the same sector of the community. The close distribution of cases suggests the same exposure source. There were 426 dogs in the community; feces were collected from 414 of these in search of cestode eggs. After treatment, 3 dogs had Taenia pisiformis but none had Echinococcus. This paper pioneers the search of human echinococcosis in México because it provides evidence of the presence of this tissue parasite at the community level.     

Growth in Children with Steroid Sensitive Nephrotic Syndrome

Background

Nephrotic syndrome in children usually has an onset between 2-8 years of age and steroids form the mainstay of management. Therapy may affect growth in children with relapsing nephrotic syndrome. This study was carried out to correlate growth with the cumulative dose of steroids in children with steroid sensitive nephrotic syndrome (SSNS).

Methods

Data of 35 children with SSNS was analysed retrospectively. They were divided into two groups. Group I received prednisolone only and Group II received levamisole and or cyclophosphamide in addition to steroids. Their heights were recorded at the time of inclusion and again one year later. The SD scores for age were determined. Growth rate as a change in the SD score over one year (Δ SD score) was correlated to the cumulative dose of steroids over the same period using the Pearson''s correlation. Result: There were 24 (68.6 %) boys and 11 (31.4 %) girls (M:F ratio 2.18:1) in the age group of 17 months to 11 years at inclusion. Group I constituted 19 (54.2 %) and Group II, 16 (45.8 %). Pearson''s correlation coefficients for all children, Groups I and II were -0.341, -0.441 and -0.255 respectively indicating “Fair correlation”. This indicates that as the cumulative dose of steroid increases the growth retardation becomes more apparent.

Conclusion

Growth retardation is proportional to the cumulative dose of steroids in children with SSNS.Key Words: Steroids, Cumulative dose, Nephrotic syndrome, Growth     

Comparison of clinical and magnetic resonance imaging diagnosis in patients with disk displacement in the temporomandibular joint.

OBJECTIVE: The purpose of this study was to validate the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for the diagnostic subgroup of disk displacement with reduction, with magnetic resonance imaging used as a gold standard. STUDY DESIGN: The diagnoses from the clinical examination of 78 joints in 39 patients, each with disk displacement with reduction in at least one TMJ, were compared with magnetic resonance imaging diagnoses. The readers of the magnetic resonance images were blinded to the clinical diagnoses. The data analysis included kappa statistics and calculation of predictive values. RESULTS: The predictive value of the RDC/TMD for disk displacement with reduction was 0.65. For disk displacement alone-the movement of the disk on opening not being considered-the predictive value was 0.92. The diagnostic agreement between RDC/TMD and magnetic resonance imaging diagnoses for all joints examined was 53.8%. Most of the disagreement was due to false negative clinical diagnoses for asymptomatic joints. CONCLUSIONS: A positive RDC/TMD examination is predictive for internal derangement but not reliable with regard to the type of disk displacement; such examination is therefore of limited value in determining the true disk position and its functional movements.     

Mutation rate at the hprt locus in human cancer cell lines with specific mismatch repair-gene defects

Spontaneous mutation rates at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus were measured in human cancer cell lines defective in the mismatch repair (MMR) genes hMLH1, hPMS2, or GTBP, as well as in a cell line carrying mutations in both hMLH1 and hPMS2. The mutation rate was determined by quantitating mutant frequency increases within a single culture as a function of cell division. These MMR- deficient cell lines exhibited a 50- to 750-fold increase in mutation rate relative to a MMR-proficient cancer cell line. From lowest to highest, the spontaneous mutation rates relative to the MMR-gene defects studied here are as follows: hMLH1- < GTBP- < hPMS2- < hMLH1- / hPMS2-. In addition, a cell line in which MMR was restored by chromosome transfer exhibited a mutation rate 12-fold below the MMR- deficient parental cell line. These data support the notion that MMR plays an important role in controlling the rate of spontaneous mutation and suggest that different MMR-gene defects may vary in their ability to repair different types of DNA mismatches, thus leading to measurable quantitative differences in spontaneous mutagenesis. Furthermore, a difference in mutation rates was observed between a hPMS2-defective cell line (3.1 x 10(-5) mutations/cell/generation) and two hMLH1- defective cell lines (4.0 x 10(-6) and 7.3 x 10(-6) mutations/cell/generation). Assuming the hPMS2- and hMLH1-gene products only function in the proposed hMutL alpha heterodimer, then defects in either gene should yield comparable mutation rates. These data suggest that hPMS2 plays a critical role in MMR, while additional hMLH1 homologues or hPMS2 alone may function to partially complement defects in hMLH1.      

B细胞能够部分自主控制命运

最近,澳大利亚和爱尔兰科学家在B细胞研究中证实B细胞可在某种程度上控制自己的命运.这一发现在很大程度上会改变科学家们对于细胞命运决定因素的理解.在淋巴结中增殖的B细胞面临着多种命运的抉择：常见的包括细胞死亡、细胞分裂、成为能够分泌抗体的细胞或是改变它们产生的抗体.过去科学界普遍认可的观点是B细胞的命运取决于例如特定激素或细胞信号分子等外部信号.而新研究发现B细胞的命运在很大程度上是由内部的程序所决定.他们开发了新型技术与图像分析方法,通过重建B细胞分化形成不同细胞类型所需的条件,对B细胞进行了追踪成像观测.结果 表明不同的细胞命运是细胞内竞争的结果.即使这些细胞获得相同的外部信号,细胞群体中发生的事件仍会出现相当大的差异.这表明激素或细胞信号分子等外部因素并非是B细胞命运的主宰因子,它们只不过能改变细胞命运选择的概率.