Temporal relation between temperature change and FDG uptake in brown adipose tissue

Objectives It has been reported that the prevalence of ¹⁸F fluorodeoxyglucose (FDG) uptake in brown adipose tissue (BAT) is related to outdoor temperature, i.e., more frequent during the colder periods of the year. The purpose of this study was to assess the temporal relationship between BAT FDG uptake and temperature. We correlated the prevalence of BAT with average temperatures (divided into five temperature ranges) of seven different durations. Methods One thousand four hundred ninety-five consecutive FDG Positron emission tomography (PET) studies in 1,159 patients (566 male and 593 female, mean age = 60.4 years) were retrospectively reviewed. FDG uptake with distinct patterns compatible with BAT was identified by a consensus of two readers. The local daily average temperature from January 2000 to November 2003 (beginning 60 days before the date of first PET scan) were obtained, and 2-, 3-, 7-, 14-, 30-, and 60-day average temperatures before the date of a PET study were calculated. The prevalence of BAT FDG uptake was correlated with these various average temperatures. Results The daily, 2-day, 3-day, and 7-day average temperature had an inverse relation with the prevalence of BAT, i.e., the lower the temperature, the higher prevalence of BAT. When the temperature was averaged over 14 days or longer, this inverse relationship between the temperature and the prevalence of BAT was no longer preserved. Conclusions Our data suggest that increased FDG uptake in BAT occurs more often as an acute response to cold weather (1–7 days) rather than to prolonged periods of average cold weather.     

Differentiation between malignant and benign pathologic fractures with F-18-fluoro-2-deoxy-<Emphasis Type="SmallCaps">D</Emphasis>-glucose positron emission tomography/computed tomography

Objective To evaluate the efficacy of F-18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) in differentiating malignant from benign pathologic fractures. Materials and methods F-18 FDG PET/CT was performed on 34 patients with pathologic fractures between May 2004 and June 2007. Fractures were located in tubular bones (26), in the pelvis (six), in the spine (one) and in a rib (one). The FDG uptake pattern at the fracture site was described, whether FDG uptake occurred in the marrow or cortex and soft tissue. Maximum standardized uptake values (SUVmax, the largest value at the region of interest) were measured at the fracture site, including cortical bone, bone marrow and soft tissue. As a reference standard, biopsy was used for 12 patients and clinical follow-up for 22 patients. Sensitivity, specificity and diagnostic accuracy of PET/CT were calculated. Results There were 19 malignant and 15 benign fractures. In the malignant fractures, PET/CT demonstrated high (mean SUVmax 12.0, range 4.3 to 45.7) F-18 FDG uptake in bone marrow in most cases (17 of 19). In benign fractures, there was low FDG uptake (mean SUVmax 2.9, range 0.6 to 5.5) within cortical bone or adjacent soft tissue around the fracture, rarely in the marrow. There were significant differences in the pattern of intramedullary FDG uptake (P < 0.001) and in the mean SUVmax (P < 0.01) between malignant and benign fractures. The sensitivity, specificity and diagnostic accuracy of F-18 FDG PET/CT were 89.5%, 86.7% and 88.2%, respectively, with a cut-off SUVmax set at 4.7. The time interval between fracture and PET/CT did not significantly influence FDG uptake at the fracture site. Conclusion F-18 FDG PET/CT reliably differentiated between malignant and benign fractures based on the SUVmax and based on medullary uptake, which was characteristic for malignant fractures. This research was supported by the Yeungnam University research grants in 2007.     

Standardized uptake values of uterine leiomyoma with <Superscript>18</Superscript>F-FDG PET/CT: variation with age,size, degeneration,and contrast enhancement on MRI

OBJECTIVE: To assess the effect of age, size, the degree of degeneration, and contrast enhancement on magnetic resonance imaging (MRI) on 18F-fluoro-2-deoxyglucose (18F-FDG) uptake in uterine leiomyomas using quantitative standardized uptake values (SUVs). METHODS: A total of 61 leiomyomas of 41 patients, who underwent combined positron emission tomography/computed tomography (PET/CT) using 18F-FDG and contrast-enhanced MRI were included in this study. Sixty-one leiomyomas were divided into two groups: "non-degenerated" leiomyomas showing distinct low signal intensity on T2-weighted images and intermediate signal intensity on T1-weighted images, and "degenerated" leiomyomas showing other types of signal intensity. Sixty-one leiomyomas were also divided into two groups of "strongly enhancing" leiomyomas and "weakly enhancing" leiomyomas in terms of their degree of contrast enhancement on MRI. RESULTS: The mean values of the maximum and average SUVs for the total of 61 leiomyomas were 2.34 +/- 0.75 (range 1.59-5.15) and 1.74 +/- 0.50 (0.66-3.95), respectively. There was a moderate negative correlation between the maximum and average SUVs and age (r = -0.43 and P = 0.00016, r = -0.31 and P = 0.029, respectively). Although there was a mild positive correlation between maximum SUV and size (r = 0.35 and P = 0.011), there was no significant difference between average SUV and size. Although there was no significant difference in average SUV between "degenerated" and "non-degenerated" leiomyomas, the maximum SUV of "degenerated" leiomyomas was significantly higher than that of "non-degenerated" leiomyomas (P = 0.0012). The degree of contrast enhancement on MRI was not significantly correlated with 18F-FDG uptake. CONCLUSIONS: Mild or moderate uptake of 18F-FDG is often observed in uterine leiomyoma and declines with age, and should not be confused with malignant accumulation.     

18 F-FDG PET/CT显像在评价不同病理亚型淋巴瘤疗效方面的价值

目的：探讨18 F-脱氧葡萄糖(18 F-FDG) PET/CT在不同病理亚型淋巴瘤疗效的评估价值。方法收集我科近4年来治疗前后均行PET/CT检查的淋巴瘤患者资料,同时根据自愿原则随机选取治疗前已行PET/CT检查的淋巴瘤患者,于治疗2~4个疗程后再次行PET/CT检查。回顾性分析并比较43例不同病理亚型淋巴瘤病灶(包括淋巴结病灶和结外灶)治疗前最大标准摄取值( SUVmax )、滞留指数( RI)和治疗后的SUVmax并进行统计学分析。所有病例随访至少3个月。结果治疗前霍奇金淋巴瘤( HL)与非霍奇金淋巴瘤( NHL)的病灶间平均SUVmax比较及RI比较差异无统计学意义。治疗前不同病理亚型的NHL淋巴瘤病灶平均SUVmax及RI与NHL的侵袭性呈正相关性,与淋巴瘤的分期无明显相关;治疗后43例患者达到完全缓解23例,部分缓解16例,疾病稳定状态1例,复发或进展3例。治疗前后淋巴瘤病灶的SUVmax差异有统计学意义(P<0．01)。结论18 F-FDG PET/CT显像对淋巴瘤患者治疗前后病灶平均SUVmax及RI的比较分析能有效评价疗效、判断预后,并为进一步治疗方案制定提供帮助和指导。     

Importance of Sample Size for the Estimation of Repeater F Waves in Amyotrophic Lateral Sclerosis

Background:

In amyotrophic lateral sclerosis (ALS), repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size.

Methods:

We studied the F waves of left ulnar nerves in ALS patients. Based on the presence or absence of pyramidal signs in the left upper limb, the ALS patients were divided into two groups: One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group. The Index repeating neurons (RN) and Index repeater F waves (Freps) were compared among the P, NP and control groups following 20 and 100 stimuli respectively. For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.

Results:

In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group. For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P and NP groups were significantly higher than the control group.

Conclusions:

Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS. For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy, 100 stimuli would be required.     

血、尿IL-18和KIM-1联合检测对冠心病患者行介入术后急性肾损伤的早期诊断意义

目的:探讨分析血、尿白细胞介素-18（interleukin 18 ,IL-18）和肾损伤分子-1（kidney injury molecule 1,KIM-1）联合检测在冠心病介入术后急性肾损伤( acute kidney injury,AKI) 早期诊断中的价值。方法：选取河南省平顶山市第二人民医院心内科收治的诊断为冠心病并行介入术治疗的患者243例,分为AKI组48例,非AKI组195例;收集所有患者术后0、2、4、6、8、10、12、24、48、72 h血液及尿液样本,检测各时间点血液样本的血清肌酐（serum creatinine,SCr）、IL-18和KIM-1,尿液样本的IL-18和KIM-1水平。结果：AKI组患者术后12、24、48、72 h SCr值均明显高于0 h基线值（P均<0.05）;AKI组术后各时间点血、尿IL-18和KIM-1水平均高于0 h基线值,IL-18在2 h（血）或4 h（尿）时达到峰值,KIM-1在6 h（血）或8 h（尿）时达到峰值（P均<0.05）;Pearson相关分析显示,AKI组术后血（2 h）、尿（4 h）IL-18和血（6 h）、尿（8 h）KIM-1水平均与术后24 h SCr呈正相关（P均<0.05）;ROC曲线分析显示,血（2 h）、尿（4 h）IL-18和血（6 h）、尿（8 h）KIM-1 ROC曲线下面积（AUC）对AKI的诊断均具有较好的诊断效能;血（2 h）、尿（4 h）IL-8和血（6 h）、尿（8 h）KIM-1联合检测诊断AKI的AUC均大于两者的单独检测。结论：对冠心病患者进行介入术后的2 h血IL-18、4 h尿IL-18、6 h血KIM-1、8 h尿KIM-1的联合检测,对早期诊断AKI具有良好的诊断效能,有一定的诊断价值,其或可成为早期诊断AKI的重要参考依据。     

microRNA-18a Promotes Cell Migration and Invasion Through Inhibiting Dicer l Expression in Hepatocellular CarcinomaIn Vitro

Objective To investigate the effects of microRNA-18a (miR-18a) on migration and invasion of hepatocellular carcinoma (HCC) cells, and its possible mechanism associated with Dicer l. Methods HepG2 and HepG2.2.15 cells were transfected with miR-18a inhibitor using Lipofectamine. Cell invasion was evaluated by transwell invasion assay, and cell migration was detected by transwell migration and wound-healing assays. Moreover, luciferase reporter assay was used to identify whether Dicer expression was regulated by miR-18a. Real-time RT-PCR and western blot were performed to analyze Dicer 1 expression. In addition, a functional restoration assay was performed to investigate whether miR-18a promotes HCC cell migration and invasion by directly targeting Dicer 1. Results miR-18a inhibitor can suppress the migration and invasion of HCC cells. Furthermore, suppression of Dicer l expression by small interfering RNA essentially abolished the inhibition of cell migration and invasion induced by miR-18a inhibitor, restorating these activities to levels similar to the parental HCC cells. Interestingly, suppression of miR-18a in HCC cells resulted in enhanced expression of Dicer l. In addition, the results of a luciferase assay demonstrated targeted regulation of Dicer l by miR-18a. Conclusion Our findings suggest that miR-18a promotes migration and invasion of HCC cells by inhibiting Dicer l expression.     

Ptosis postcardiac surgery: a case of pituitary apoplexy

We present a patient in whom ptosis and third cranial nerve palsy developed postcoronary artery bypass grafting, and discuss the management of pituitary apoplexy postcardiac surgery.     

The decrease in serum IL-18 levels after bariatric surgery in morbidly obese women is a time-dependent event

Background We have evaluated the impact of the reproductive status of morbidly obese women, and of the time elapsed since surgery, on the response of the proinflammatory serum cardiovascular risk marker interleukin-18 (IL-18) to the sustained and marked weight loss achieved after bariatric surgery. Methods Serum IL-18 levels were measured in 33 morbidly obese women before bariatric surgery and after losing at least 15% of the initial weight, irrespective of the time needed to achieve this goal (5 to 33 months). Results Patients lost 30.7 ± 7.8% of the initial weight, with a concomitant reduction of serum IL-18 concentrations (P < 0.001). A stepwise multiple regression analysis showed that the percentual decrease in serum IL-18 levels was determined by the interaction between the time elapsed since surgery and the percentual reduction of waist circumference (R² = 0.333, F = 15.500, β = 0.577, P < 0.001), but not by the individual effects of the time elapsed since surgery, percentual body weight loss, percentual reduction of waist circumference, menopausal status or type of surgical procedure, or by the interaction between the time elapsed since surgery with the percentual body weight loss or with menopausal status. Conclusion Serum IL-18 levels decrease after bariatric surgery in a time-dependent manner, in relation to the reduction in waist circumference. The fact that the amelioration of the obesity-associated inflammatory process requires time and not only weight loss, might contribute to explain early non-surgical cardiovascular complications of bariatric surgery.     

Effect of fenfluramine-induced increases in serotonin release on [18F]MPPF binding: a continuous infusion PET study in conscious monkeys

[(18)F]MPPF is a selective and reversible antagonist to the serotonin-1A (5-HT(1A)) receptor. The aim of the present study was to investigate whether the binding of [(18)F]MPPF is sensitive to increases in 5-HT levels. We used the 5-HT releasing agent and reuptake inhibitor fenfluramine (FEN) to increase the concentration of 5-HT. [(18)F]MPPF binding was assessed using positron emission tomography (PET) in conscious monkeys. Possible effects of blood flow on ligand binding were excluded by using a bolus-infusion paradigm. Control scans were obtained to assess the state of ligand equilibrium. FEN (5 or 10 mg/kg, i.v.) was administered between 90 and 130 min after the start of the [(18)F]MPPF infusion. The binding potential (BP) was calculated for an early interval (30 min preceding FEN administration) and late interval (20-50 min after administration of FEN). Microdialyses results showed a 20- and 35-fold increase in extracellular 5-HT levels in the prefrontal cortex after injection of FEN at a dose of 5 mg/kg and 10 mg/kg respectively. However, despite these large increases in 5-HT levels, no differences in BP were found between the control and FEN scans. These results may imply that the majority of 5-HT(1A) receptors is in the low affinity state in the living brain.