Spatial distribution, source identification, and transportation paths of plutonium in the Beibu Gulf, South China Sea.

To investigate the spatial distribution and source of plutonium isotopes in the Beibu Gulf, surface sediments were collected and analyzed using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). The activities of 239+240Pu in surface sediments ranged from 0.012 to 0.451 mBq/g (mean: 0.171 ± 0.138 mBq/g, n = 36), indicating a decreasing trend in a counterclockwise direction from the southern bay mouth. The counterclockwise decreasing trend in the south of the bay mouth is similar to the current in the Beibu Gulf. The 240Pu/239Pu atom ratios in surface sediments ranged from 0.156 to 0.283 (mean: 0.236 ± 0.031, n = 36), slightly higher than that of the global fallout value of 0.18. This suggests that the Pu in the Beibu Gulf was a combination of global fallout and Pacific Proving Ground (PPG). The average contribution of the plutonium (Pu) derived from the PPG in the sediment was estimated to be 52 % ± 24 %.

Plutonium isotopes and radionuclides in corals around Weizhou land in Beibu Gulf, China.

Plutonium isotopes in the coral were determined with chemical separation method using AG 1-X8 and AG-MP-1M anion exchange resins and sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) in order to elucidate the activity concentration and source of Pu around Weizhou land in Beibu Gulf, China. Furthermore, the activity concentrations of other radionuclides (238U, 226Ra, 232Th, 137Cs, 40K and 210Pb) were measured by a HPGe spectrometer. The activity concentration of 240+239Pu in the coral is determined to be in the range of 8.95-27.84 mBq/kg. The 240Pu/239Pu atom ratios in the samples range from 0.173 to 0.225, indicating that the main source of plutonium in this area is global fallout while the contribution of PPG is about 30%. Further, the activity concentrations of 238U, 232Th, 40K and 226Ra are determined to be in the range of 18.72-64.63, 1.37-20.8, 29.78-72.52 and 3.48-61.97 Bq/kg, respectively.

Diffusion tensor imaging of microstructural alterations in the trigeminal nerve due to neurovascular contact/compression.

BACKGROUND: Several recent studies have focused on microstructural changes in the trigeminal nerve in trigeminal neuralgia using diffusion tensor imaging (DTI). However, alterations after microvascular decompression (MVD) have rarely been investigated. Furthermore, the trigeminal nerve of asymptomatic individuals also presenting with neurovascular contact/compression (NVC) has not yet been studied. METHODS: Thirty-four patients suffering from trigeminal neuralgia and 34 healthy age-matched controls, who were identified as having unilateral NVC signs, underwent both DTI and high-resolution magnetic resonance imaging (MRI) for comparison. All trigeminal neuralgia patients underwent a post-surgical MRI scan after 7 days and a follow-up MRI scan within 6-8 months after surgery. The apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) values were measured from coronal images in which the nerves from the root exit point to the distal segment were clearly shown. RESULTS: In 34 trigeminal neuralgia patients, the absolute FA value was significantly lower on the affected side (mean FA, 0.34 ± 0.03) than on the unaffected side (mean FA, 0.37 ± 0.05, p < 0.001). The FA ratio was also significantly different between the trigeminal neuralgia group (RsFA, 0.92 ± 0.06) and the control group (RsFA, 0.99 ± 0.09) (p = 0.001). The absolute ADC value between the two sides in patients and the ratios of ADC between the trigeminal neuralgia and control groups did not show any significant differences (p = 0.21 and 0.29, respectively). However, in 34 healthy subjects presenting with signs of NVC, neither the FA value nor the ADC showed a difference between sides (p > 0.05). The FA ratio of patients showed a significant increase on two follow-up MRI scans compared to the preoperative FA (p = 0.02 and 0.002, respectively), while the ADC ratio showed a significant decrease at 6 months after MVD (p = 0.004). CONCLUSION: This study of trigeminal neuralgia due to NVC found that DTI indexes could reflect alterations in the affected trigeminal nerve. Furthermore, a reversible change after MVD surgery could be potentially valuable for monitoring the change in white matter of the trigeminal nerve.

Bisphenol A induced abnormal DNA methylation of ovarian steroidogenic genes in rare minnow Gobiocypris rarus.

Bisphenol A (BPA), an ubiquitous environmental endocrine disruptor chemical, disturbs the mRNA expressions of steroidogenic genes and subsequently steroid hormone synthesis in mammals and aquatic species. However, the underlying regulation mechanisms are barely understood, especially in fish. To explore the regulation mechanism, we exposed female rare minnow Gobiocypris rarus (G. rarus) to BPA at a nominal concentration of 15 µg/L for 7 and 14 days in the present study. Results showed significant increase of gonad somatic index (GSI) and serum estradiol (E2) levels in response to BPA at day 14. The 7-day BPA exposure notably repressed the expression of two ovarian steroidogenic genes (star and hsd11b2) and suppressed their capacity of estrogen response elements (ERE) to recruit estrogen receptor (ER), while the 14-day BPA treatment remarkably induced transcript of hsd3b and enhanced the capacity of ERE to recruitment ER in ovaries. Furthermore, the 7-day BPA exposure caused DNA hypermethylation of star (CpGs: -742 bp and -719 bp) and hsd11b2 (CpG: -1788 bp). However, 14-day BPA exposure resulted in DNA hypomethylation of hsd3b (CpG: -181 bp). Correlation analysis revealed that the DNA methylation levels at specific CpGs in star, hsd3b and hsd11b2 were significantly correlated to their mRNA levels and ER-EREs interactions. These findings suggest that the disturbed steroidogenesis and the transcripts of ovarian steroidogenic genes might attribute to the altered DNA methylation status of these ovarian steroidogenic genes in response to BPA.

Discriminating Depth of Response to Therapy in Multiple Myeloma Using Whole-body Diffusion-weighted MRI with Apparent Diffusion Coefficient: Preliminary Results From a Single-center Study.

RATIONALE AND OBJECTIVES: This study aimed to measure apparent diffusion coefficient (ADC) in Chinese patients with newly diagnosed multiple myeloma by whole-body diffusion-weighted magnetic resonance imaging (WB-DWI MRI) and assess the diagnostic accuracy of ADC in the discrimination of deep response to induction chemotherapy. MATERIALS AND METHODS: Seventeen patients underwent WB-DWI MRI before and after induction chemotherapy (week 20). DWI images and ADC maps were produced and 89 regions of interest were chosen. ADC percent changes were compared between deep (complete response or very good partial response) and non-deep responders (partial response, minimal response, stable disease, or progressive disease) as International Myeloma Working Group criteria. Diagnostic accuracy of ADC was calculated using specific cut offs. Predictive positive value of ADC was calculated to predict deep response to consolidation therapy. RESULTS: Lesions reduced in size and number and signal intensity decreased in follow-up DWI, which did not differ between deep and non-deep responders. ADC percent changes were significantly higher in deep responders (36.79%) than in non-deep responders (11.50%) after induction therapy (P = .02) in per lesion analysis. ADC percent increases by 46.96%, 78.0% yielded specificity at 81.4%, 90.7% in discriminating deep response to induction therapy. Predictive positive value predicting deep response to consolidation therapy was 60.5% by using ADC cutoff >1.00 × 10-3 mm2/s at week 20. CONCLUSIONS: ADC from WB-DWI MRI increased remarkably in patients who achieved deep response at the end of induction chemotherapy, which represented a confirmatory diagnostic tool to discriminate deep response to induction therapy for patients with multiple myeloma. ADC may have a potential to predict deep response to consolidation therapy.

Bisphenol A regulates rare minnow testicular vitellogenin expression via reducing its promoter Er recruitment.

Vitellogenins (Vtgs) are major precursor of the egg-yolk proteins. They are synthesized in liver of adult female ovipara, but normally silent in males. For their sensitive response to estrogen, Vtgs are usually used as biomarkers for environmental estrogenic compounds. In the present study, three vtg subtypes (vtg1, vtg2 and vtg3) were proved to present in the testis of rare minnow Gobiocypris rarus for the first time. Immunohistochemistry result showed that Vtg proteins mainly deposit in spermatogonium and spermatocytes. Following 225µg/L bisphenol A (BPA) exposure 1, 3 and 9 weeks, testicular vtg mRNAs were mostly significantly decreased. The further chromatin immunoprecipitation showed that BPA could decrease estrogen receptor (Er) recruitment in vtg promoter, which possibly reduced Er's transcription activation effect on vtgs. However, different from the continuously decreased vtg mRNA levels, testicular Vtg protein levels were recovered at week 9. Considering the induced hepatic Vtg expression, testicular Vtgs may be replenished by the induced hepatic Vtgs under BPA exposure.

Simultaneous Imaging of Cerebrovascular Structure and Function in Hypertensive Rats Using Synchrotron Radiation Angiography.

Hypertension has a profound influence on the structure and function of blood vessels. Cerebral vessels undergo both structural and functional changes in hypertensive animals. However, dynamic changes of cerebrovasculature and the factors involved in this process are largely unknown. In this study, we explored the dynamic changes of vascular structure in hypertensive rats using novel synchrotron radiation angiography. Twenty-four spontaneously hypertensive rats (SHR) and 24 Sprague-Dawley (SD) rats underwent synchrotron radiation (SR) angiography. Each group had 8 animals. We studied the cerebral vascular changes in SHR over a time period of 3-12-month and performed quantitative analysis. No vascular morphology differences between SHR and SD rats were observed in the early stage of hypertension. The number of twisted blood vessels in the front brain significantly increased at the 9- and 12-month observation time-points in the SHR compared to the SD rats (p < 0.01). The vessel density of the cortex and the striatum in SHR was consistently higher than that in SD rats at time points of 3-, 9-, and 12-month (p < 0.001). Vascular elasticity decreased both in SHR and SD rats with aging. There were statistically significant differences in the relative vascular elasticity of extracranial/intracranial internal carotid artery, middle cerebral artery, posterior cerebral artery and anterior cerebral artery between SHR and SD rats at 12-month (p < 0.01). We concluded that the dynamic vascular alterations detected by SR angiography provided novel imaging data for the study of hypertension in vivo. The longer the course of hypertension was, the more obvious the vascular differences between the SHR and the SD rats became.

Molecular identification of Kiss/GPR54 and function analysis with mRNA expression profiles exposure to 17α-ethinylestradiol in rare minnow Gobiocypris rarus.

17α-ethinylestradiol (EE2) is a widely existed endocrine disrupting chemical in water environment. Kisspeptins act as indispensable regulators through GPR54 in the hypothalamic-pituitary-gonadal (HPG) axis. This study aimed to provide further understanding of the effect of EE2 on HPG axis. Molecular cloning and tissue distribution of kiss genes and GPR54s were performed in Gobiocypris rarus. The mRNA expression profiles of kiss1, kiss2, GPR54s and GnRHs were detected in G. rarus brain and/or gonad following 3- and 6-days EE2 (1, 5, 25 and 125 ng/L) exposure. Results showed that kiss genes and GPR54s were highly expressed in brain and gonad. Both kiss1 and kiss2 were increased in female brain and suppressed in male brain following EE2 exposure. GnRHs were inhibited in a concentration-dependent manner in male brain following 3-days EE2 exposure. In gonad, GPR54b was almost suppressed in all of EE2 concentrations. The present findings suggest that EE2 impacts the genes expression of Kiss/GPR54-GnRH system in G. rarus, thereby probably disturbing the neuroendocrine homeostasis.

Effect of low-dose malathion on the gonadal development of adult rare minnow Gobiocypris rarus.

Malathion is an organophosphorus pesticide that extensively used in agriculture and veterinary practices. To investigate the effects of low dose malathion on rare minnow Gobiocypris rarus gonadal development, we exposed adult rare minnow to environmentally relevant concentration malathion (2 and 20µg/L) for 21 days. Gonadal histology, sex hormone levels and mRNA expressions of steroidogenic genes were investigated. Malathion at both 2 and 20µg/L significantly up-regulated rare minnow testicular weight and promoted the progression of spermatogenesis. Neither ovarian weight nor process of ovary development was markedly changed. In testis, 2µg/L malathion significantly down-regulated testosterone and 11-ketotestosterone levels, and up-regulated mRNA expression of steroidogenic genes. In ovaries, 2 and 20µg/L malathion significantly inhibited estradiol17ß levels and induced testosterone levels, both in concentration dependent manners; mRNA expressions of almost all the detected ovarian steroidogenic genes were up-regulated. The present result suggested that malathion even at low dose could pose a potential threat to adult rare minnow gonadal development.

Development of functional in vivo imaging of cerebral lenticulostriate artery using novel synchrotron radiation angiography.

The lenticulostriate artery plays a vital role in the onset and development of cerebral ischemia. However, current imaging techniques cannot assess the in vivo functioning of small arteries such as the lenticulostriate artery in the brain of rats. Here, we report a novel method to achieve a high resolution multi-functional imaging of the cerebrovascular system using synchrotron radiation angiography, which is based on spatio-temporal analysis of contrast density in the arterial cross section. This method provides a unique tool for studying the sub-cortical vascular elasticity after cerebral ischemia in rats. Using this technique, we demonstrated that the vascular elasticity of the lenticulostriate artery decreased from day 1 to day 7 after transient middle cerebral artery occlusion in rats and recovered from day 7 to day 28 compared to the controls (p < 0.001), which paralleled with brain edema formation and inversely correlated with blood flow velocity (p < 0.05). Our results demonstrated that the change of vascular elasticity was related to the levels of brain edema and the velocity of focal blood flow, suggesting that reducing brain edema is important for the improvement of the function of the lenticulostriate artery in the ischemic brain.

Surgery-related thrombosis critically affects the brain infarct volume in mice following transient middle cerebral artery occlusion.

Transient middle cerebral artery occlusion (tMCAO) model is widely used to mimic human focal ischemic stroke in order to study ischemia/reperfusion brain injury in rodents. In tMCAO model, intraluminal suture technique is widely used to achieve ischemia and reperfusion. However, variation of infarct volume in this model often requires large sample size, which hinders the progress of preclinical research. Our previous study demonstrated that infarct volume was related to the success of reperfusion although the reason remained unclear. The aim of present study is to explore the relationship between focal thrombus formation and model reproducibility with respect to infarct volume. We hypothesize that suture-induced thrombosis causes infarct volume variability due to insufficient reperfusion after suture withdrawal. Seventy-two adult male CD-1 mice underwent 90 minutes of tMCAO with or without intraperitoneal administration of heparin. Dynamic synchrotron radiation microangiography (SRA) and laser speckle contrast imaging (LSCI) were performed before and after tMCAO to observe the cerebral vascular morphology and to measure the cerebral blood flow in vivo. Infarct volume and neurological score were examined to evaluate severity of ischemic brain injury. We found that the rate of successful reperfusion was much higher in heparin-treated mice compared to that in heparin-free mice according to the result of SRA and LSCI at 1 and 3 hours after suture withdrawal (p<0.05). Pathological features and SRA revealed that thrombus formed in the internal carotid artery, middle cerebral artery or anterior cerebral artery, which blocked reperfusion following tMCAO. LSCI showed that cortical collateral circulation could be disturbed by thrombi. Our results demonstrated that suture-induced thrombosis was a critical element, which affects the success of reperfusion. Appropriate heparin management provides a useful approach for improving reproducibility of reperfusion model in mice.

Effect of suture properties on stability of middle cerebral artery occlusion evaluated by synchrotron radiation angiography.

BACKGROUND AND PURPOSE: The intraluminal suture technique for producing middle cerebral artery occlusion in rodents is the most commonly used method for modeling focal cerebral ischemia associated with clinical ischemic stroke. Synchrotron radiation angiography may provide a novel solution to directly monitor the success of middle cerebral artery occlusion. METHODS: Twenty adult Sprague-Dawley rats for middle cerebral artery occlusion models were prepared randomly with different suture head silicone coating. In vivo imaging was performed at beam line BL13W1, Shanghai Synchrotron Radiation Facility, Shanghai, China. RESULTS: Silicone-coated suture was superior to uncoated suture for producing consistent brain infarction. Additionally, silicone coating length was an important variable controlling the extent of the ischemic lesion: infarcts affected predominantly the caudate-putamen with large variability (<2 mm), both the cortex and caudate-putamen (2-3.3 mm), and most of the hemisphere, including the hypothalamus (>3.3 mm). CONCLUSIONS: Synchrotron radiation angiography provides a useful tool to observe hemodynamic changes after middle cerebral artery occlusion, and the physical properties of suture are critical to the success of the middle cerebral artery occlusion model.

Cauda equina hemangioblastoma at L5 vertebral level related to von Hippel-Lindau disease.

Hemangioblastoma (HB) is uncommon, with only a few cases of hemangioblastoma with von Hippel-Lindau disease (VHL) located in cauda equina previously reported. We describe a case of hemangioblastoma misdiagnosed as nerve sheath tumour in the cauda equina.

Optimizing suture middle cerebral artery occlusion model in C57BL/6 mice circumvents posterior communicating artery dysplasia.

The suture middle cerebral artery occlusion (MCAO) model is used worldwide in both academia and industry. However, the variable occurrence of dysplasia in posterior communicating arteries (PcomAs) induces high mortality and instability in permanent MCAO models, limiting the model's application to transient focal ischemia. In particular, high mortality in intraluminal suture MCAO models is associated with the dysplasia of PcomAs in C57BL/6 mice. Optimization of silicone coating length is critical for reducing mortality and generating stable infarct in this model. The aim of our study is to reduce mortality and improve the reproducibility of the intraluminal suture MCAO model in C57BL/6 mice, which have high variation in PcomA dysplasia. Adult male C57BL/6 mice (n=38) underwent MCAO using sutures with various diameters and silicone coating lengths. The occlusion of cerebral vessels was examined by synchrotron radiation live angiography. The morphology of PcomAs was examined under a microscope after MICROFIL(®) infusion. Neurological outcome, infarct volume, and mortality were examined within 28 days. Optimizing the silicone coating on an 8-0 suture tip, we were able to reduce the model mortality to zero after permanent occlusion in C57BL/6 and produce stable brain infarct volume independent of the patency of PcomAs.

Microbubble-based synchrotron radiation phase contrast imaging: basic study and angiography applications.

The purpose of the study was to evaluate the feasibility of microbubbles as phase contrast imaging (PCI) agents for angiography applications. The hypothesis was that the introduction of microbubbles into tissue produces a significant change in the refractive index and highlights the lumen of the vessel in PCI. The absorption and phase contrast images of commercially available microbubbles were obtained and compared in vitro. A further increase in contrast was observed in PCI. Microbubbles highlighted the lumen of the renal microvessels, acting as a positive contrast medium in ex vivo imaging. In addition, home-made microbubbles with larger diameters were introduced for image contrast enhancement in living tumor-bearing mice, demonstrating the feasibility of microbubble-based x-ray phase-contrast imaging for tumor vasculature in vivo.

Correlation of iron in the hippocampus with MMSE in patients with Alzheimer's disease.

PURPOSE: To investigate the brain iron deposits in patients with Alzheimer's disease (AD) and healthy age-matched controls using phase imaging. MATERIALS AND METHODS: Twenty-six AD patients and 24 healthy controls were recruited. A three-dimensional high-resolution, gradient-echo sequence was used to acquire phase data in the coronal plane. A high-pass filter was used to remove the phase variation caused by field inhomogeneity. The regions evaluated included the bilateral putamen, globus pallidus, and the head and body of the hippocampus. RESULTS: Significantly lower phase values in both the basal ganglion and hippocampus were revealed in the AD group compared to the normal controls (P < 0.05). The phase value in the right side of the head of the hippocampus had a moderate positive correlation with the MMSE score (r= 0.603, P = 0.000) and a negative correlation with the duration of the disease (r = -0.677, P = 0.013). Using -0.0972 radians as an optimal cutoff value, the sensitivity and specificity for differentiation between AD and normal controls reached 95.8 and 80.8%, respectively. CONCLUSION: Phase imaging proved to be a useful method for the differentiation between normal controls and AD patients. An investigation of the excessive accumulation of iron in the hippocampus may help us better understand the pathologic process and neuropsychological dysfunction of AD disease.

Preliminary application of whole body diffusion weighted imaging in screening metastasis.

OBJECTIVE: To investigate the feasibility of whole body diffusion weighted imaging (WB-DWI) in screening metastasis. METHODS: WB-DWI was performed in 24 patients diagnosed with various types of primary tumors. The three-dimensional maximum intensity projection reconstruction and black-and-white flip technique were used to observe metastatic lesions, and the results were compared with those of bone scintigraphy. RESULTS: By WB-DWI scanning sequence at b = 800 s/mm2, all the bone lesions found by bone scintigraphy in the cohort were well identified, and other lesions of soft tissue and organs were also well demonstrated. Its screening capability was equivalent with bone scintigraphy in screening metastases in bones (P = 0.062). CONCLUSION: WB-DWI was practicable with the parameter settings attempted in metastases screening.