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To investigate the in vivo effects of dehydroepiandrosterone (DHEA) on knee joints during the development of experimentally induced osteoarthritis (OA). Twenty‐two mature NZW rabbits underwent bilateral anterior cruciate ligament transection (ACLT) and received 0.3‐ml intraarticular injections of DHEA (at a concentration of 100 μM in phosphate buffered saline) and control solution in the right and left knees, respectively, beginning 4 weeks after ACLT and continuing once weekly for 5 weeks. All animals were killed 9 weeks after surgery, and the knee joints were assessed by gross morphologic, histologic, histomorphometric, and biochemical methods. Gross morphologic inspection following India ink application showed that the right femoral condyles, which received DHEA, demonstrated less severe cartilage damage than did the contralateral condyles. The thickness, area, and roughness of the DHEA‐treated femoral condyles provided evidence of a cartilage‐protecting effect of DHEA following ACLT. These results were supported by gene expression analysis. Messenger RNA expression of a proinflammatory cytokine, interleukin‐1β, and catabolic enzymes, matrix metalloproteinases 1 and 3, was reduced in the cartilage of the DHEA‐treated knee joints, and expression of tissue inhibitor of metalloproteinase 1 was increased. Results of the present study demonstrate a cartilage‐protecting effect of DHEA during the development of OA following ACLT in a rabbit model. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) imaging reporter genes, such as HSV1-tk and D2 receptor genes, make it possible to visualise gene expression non-invasively and repetitively in vivo. However, these systems require the synthesis of complicated substrates and the availability of expensive PET equipment. Expression of the sodium/iodide symporter (NIS) gene can be easily monitored with radioiodines and technetium-99m using a gamma camera. To evaluate the possibility of using NIS as an imaging reporter gene, we compared its characteristics with those of the conventional HSV1-tk gene. The CM cell line was made by transfecting the HSV1-tk gene into CT-26 (mouse colon carcinoma cell line). The CTN and CMN cell lines were then made by transfecting the NIS gene into CT-26 and CM. We measured the uptake of iodine-125 iodovinyldeoxyuridine ([125I]IVDU) and 125I to evaluate the expression of the HSV1-tk and NIS genes, respectively. Each cell line was injected into four flank sites in Balb/c mice. The biodistribution study was performed after intravenously injecting [125I]IVDU and 131I, and 131 I scintigraphy was performed for the evaluation of NIS expression. In vitro studies indicated that CTN and CMN had 40- to 79-fold and 150- to 256-fold higher uptake of 125 I than CT-26 and CM, respectively. Furthermore, CM and CMN showed 57- to 69-fold higher uptake of [125I]IVDU than CT-26 and CTN. NIS gene expression and 125I accumulation were found to be directly correlated (R 2=0.923), as were HSV1-tk gene expression and [125I]IVDU accumulation (R 2=0.956). Calculated signal per unit NIS and HSV1-tk mRNA expression was 23,2407±3,755 cpm and 34,039±5,346 cpm, re spectively. In vivo study indicated that CTN and CMN had 2.3- and 5.8-fold higher uptake of 131 I than CT-26 and CM, and 1.8- and 3.5-fold higher uptake of [125I]IVDU than CT-26 and CTN. Scintigraphy using 131I easily visualised CTN and CMN tumours. In conclusion, the NIS gene may be viewed as an imaging reporter gene with comparable performance to the HSV1-tk gene for monitoring target gene expression. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the prognostic value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) with that of second-look laparotomy (SLL) in patients with advanced ovarian carcinoma following primary chemotherapy. Fifty-five patients who had undergone cytoreductive surgery and adjuvant chemotherapy for advanced ovarian carcinoma were enrolled in the study. Thirty patients underwent SLL after primary treatment (SLL group), while 25 underwent FDG PET after primary treatment without SLL (PET group). We retrospectively reviewed the medical records of the 55 patients for comparison of progression-free interval and disease-free interval between the two groups. Ovarian carcinomas recurred in 37 of the 55 patients. When the progression-free interval and the disease-free interval in patients in the PET group were compared with those in the SLL group, no significant differences were observed. The progression-free interval in the PET and SLL groups were 28.8±12.7 months and 30.6±13.7 months, respectively (P=0.29). The disease-free interval in the negative PET group was 40.5±11.6 months, and that in the negative SLL group was 48.6±12.1 months (P=0.12). In conclusion, FDG PET has a similar prognostic value to SLL, and can substitute for SLL in the follow-up of patients who have had ovarian carcinoma, especially when there is a high risk for recurrence. [ABSTRACT FROM AUTHOR]

In regions with a high prevalence of granulomatous diseases, benign inflammatory fluorine-18 fluorodeoxyglucose (FDG) uptake in the mediastinum is frequently observed even in healthy subjects. We examined parameters of mediastinal FDG uptake to determine whether they can differentiate malignancy from benign lesions. Seventy patients with non-thoracic tumours who had mediastinal uptake on FDG positron emission tomography (PET) were included (33 males, 37 females; age 57.5±16.9 years; 168 lymph nodes). Determination of metastasis was confirmed by biopsy or computed tomography (CT) follow-up over 12 months (metastasis, 29; benign lesions, 41). No significant difference between the metastasis group and the benign group was found in terms of residual disease in the primary site (48% vs 46%), lung invasion (29% vs 20%), number of sites of uptake (2.3 vs 2.4), smoking history (30.3% vs 46.3%) or bilateral uptake (52% vs 54%). Maximal standardised uptake values (SUVs) in the mediastinal metastasis group were higher (4.9±1.8) than those in the benign group (2.5±0.9) (P<0.05). Using 3.4 as a cut-off value for maximal SUV, a sensitivity of 86% and a specificity of 85% were achieved (AUC=0.917). Maximal SUV showed better predictive value than lymph node size measured on chest CT (P<0.05). In 8 of 51 normal subjects who underwent FDG PET as a routine check-up, mediastinal FDG uptake was observed. Maximal SUV in normal subjects was 2.5±0.8, which was similar to that in the benign group. In conclusion, maximal SUV was identified as a significant parameter for determining whether mediastinal FDG uptake represents malignant metastasis. When maximal SUV exceeded 3.4, the metastasis rate was high regardless of lymph node size. [ABSTRACT FROM AUTHOR]

For homogeneous delivery of β radiation to skin cancer, we developed a simple method for preparing 188Re-labeled nitrocellulose paper. The homogeneity and stability of the labeled paper were investigated. Absorbed dose estimates were calculated using the Monte-Carlo method. A 74-MBq 188Re-labeled paper with 1-cm diameter delivered 147.2 Gy up to 1-mm depth after 2-h irradiation. Animal experiments on tumor-bearing mice showed that 50 Gy is an adequate dose for treating skin cancer. Tumors disappeared 7 days after irradiation in all the groups irradiated by 50 or 100 Gy. The 188Re-labeled paper provided a convenient, economical, effective, and non-invasive method of treating skin cancer. [Copyright &y& Elsevier]

Objective: The prefrontal-parietal circuits have been reported to play an important role in working memory. The purpose of this study was to use direct neuroimaging to address whether interregional correlation in the prefrontal-parietal circuits is impaired in schizophrenia. Method: [[sup 15]O]H[sub 2]O positron emission tomography was used to compare regional blood flow changes in 12 schizophrenic and 12 healthy comparison subjects durlng the n-back sequential-picture working memory task. Interregional correlation was assessed by correlating the regional activation of the lateral prefrontal area with that of other activated areas in each subject group. Results: Dorsolateral prefrontal activation was observed around the right superior frontal sulcus in the healthy subjects, and ventrolateral prefrontal activation below the right inferior frontal sulcus was observed in the schizophrenic patients. Activation in the right lateral prefrontal cortex was significantly correlated with activation in the bilateral inferior parietal region in the healthy subjects but was not correlated with any regional activation in the patients. Conclusions: The findings suggest prefrontal-parietal functional disconnection, particularly prefrontal dissociation and abnormal prefrontal-parietal interaction, during working memory processing in schizophrenia. [ABSTRACT FROM AUTHOR]

An independent component model of multiple subjects' positron emission tomography (PET) images is proposed to explore the overall functional components involved in a task and to explain subject specific variations of metabolic activities under altered experimental conditions utilizing the Independent component analysis (ICA) concept. As PET images represent time-compressed activities of several cognitive components, we derived a mathematical model to decompose functional components from cross-sectional images based on two fundamental hypotheses: (1) all subjects share basic functional components that are common to subjects and spatially independent of each other in relation to the given experimental task, and (2) all subjects share common functional components throughout tasks which are also spatially independent. The variations of hemodynamic activities according to subjects or tasks can be explained by the variations in the usage weight of the functional components. We investigated the plausibility of the model using serial cognitive experiments of simple object perception, object recognition, two-back working memory, and divided attention of a syntactic process. We found that the independent component model satisfactorily explained the functional components involved in the task and discuss here the application of ICA in multiple subjects' PET images to explore the functional association of brain activations. Hum. Brain Mapping 18:284–295, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Presents a study which described the cyclic activity of a maize transposable element dissociation (Ds) in rice. Materials and methods used; Inactivation of the Ds element in rice; Reactivation of Ds and the expression pattern of activator; Comparison of Ds and the retrotransposable element Tos17.