A cone-beam volume CT using a 3D angiography system with a flat panel detector of direct conversion type: usefulness for superselective intra-arterial chemotherapy for head and neck tumors.

BACKGROUND AND PURPOSE: The development of flat panel detectors (FPDs) has made cone-beam CT feasible for practical use in a clinical setting. Our purpose was to assess the usefulness of cone-beam CT using the FPD in conjunction with conventional digital subtraction angiography (DSA) for performing superselective intra-arterial chemotherapy for head and neck tumors. MATERIALS AND METHODS: Twenty-three consecutive patients (43 feeding arteries) were prospectively examined. All of the patients underwent intra-arterial rotational angiography using an FPD system, and the cone-beam CT was reconstructed from the volume dataset. Two radiologists evaluated the quality of the cone-beam CT and then evaluated whether the additional information provided by the cone-beam CT was useful for the interventional procedures. RESULTS: In 41 (95%) of 43 arteries, the extent of contrast material perfusion was sufficiently visualized on cone-beam CT. In 20 (47%) of 43 arteries, the DSA plus cone-beam CT was superior to the DSA alone regarding the precise understanding of vascular territory of each artery. This information was helpful for predicting the drug delivery for superselective intra-arterial chemotherapy, especially in deeply invasive tumors with multiple feeding arteries. CONCLUSION: In superselective intra-arterial chemotherapy for head and neck tumors, cone-beam CT with FPD provides useful additional information, which allows interventional radiologists to determine the feeders, as well as the dose of antitumor agent for each feeder.

3D digital subtraction angiography of intracranial aneurysms: comparison of flat panel detector with conventional image intensifier TV system using a vascular phantom.

BACKGROUND AND PURPOSE: Compared with the image intensifier (I.I.)-TV system, the flat panel detector (FPD) system of direct conversion type has several theoretic advantages, such as higher spatial resolution, wide dynamic range, and no image distortion. The purpose of this study was to compare the image quality of 3D digital subtraction angiography (DSA) in the FPD and conventional I.I.-TV systems using a vascular phantom. MATERIALS AND METHODS: An anthropomorphic vascular phantom was designed to simulate the various intracranial aneurysms with aneurysmal bleb. The tubes of this vascular phantom were filled with 2 concentrations of contrast material (300 and 150 mg I/mL), and we obtained 3D DSA using the FPD and I.I.-TV systems. First, 2 blinded radiologists compared the volume-rendering images for 3D DSA on the FPD and I.I.-TV systems, looking for pseudostenosis artifacts. Then, 2 other radiologists independently evaluated both systems for the depiction of the simulated aneurysm and aneurysmal bleb using a 5-point scale. RESULTS: For the degree of the pseudostenosis artifacts at the M1 segment of the middle cerebral artery at 300 mg I/mL, 3D DSA with FPD system showed mild stenoses, whereas severe stenoses were observed at 3D DSA with I.I.-TV system. At both concentrations, the FPD system was significantly superior to I.I.-TV system regarding the depiction of aneurysm and aneurysmal bleb. CONCLUSION: Compared with the I.I.-TV system, the FPD system could create high-resolution 3D DSA combined with a reduction of the pseudostenosis artifacts.

Reduction of radiation dose for cerebral angiography using flat panel detector of direct conversion type: a vascular phantom study.

BACKGROUND AND PURPOSE: Compared with image intensifier television (I.I.-TV) system, an angiography system using the flat panel detector (FPD) of direct conversion type has a high spatial resolution, which may improve image quality, reduce patient exposure, or both. Our purpose was to evaluate the detection of simulated aneurysmal blebs under dose reduction with the FPD system in comparison with the I.I.-TV system. MATERIALS AND METHODS: A vascular phantom was designed to simulate various intracranial aneurysms with and without blebs, and this phantom was filled with 3 different concentrations of contrast material (300, 150, and 100 mg I/mL). 2D digital subtraction angiography (DSA) at low-dose mode of FPD system was compared with 2D DSA at a standard-dose mode of FPD system and a conventional mode of I.I.-TV system. Data analysis was based on 171 observations (57 aneurysms [20 with bleb and 37 without bleb] x 3 contrast material concentrations) by each of 7 radiologists, and the detection performances of blebs were compared using a receiver operating characteristic (ROC) analysis. RESULTS: The mean dose measurements with a phantom during 2D DSA were 0.36 mGy/frame with low-dose mode of FPD system, 0.72 mGy/frame with standard-dose mode of FPD system and 0.76 mGy/frame with I.I.-TV system. The mean Az at 100 mg I/mL was significantly higher for low-dose mode of FPD than for conventional-dose mode of I.I.-TV mean Az, 0.85 versus 0.56; P < .01), though differences were not significant with 150 and 300 mg I/mL between both systems. CONCLUSION: The FPD system allows a considerable dose reduction during 2D DSA without loss of the image quality.

Arthroscopic diagnosis of tibiofibular syndesmosis disruption.

PURPOSE: We have been able to diagnose tibiofibular syndesmosis injury by ankle arthroscopy, and in the present study we compare these results with the results from plain radiographs. TYPE OF STUDY: Case series. METHODS: Thirty-eight type-B (Weber system) distal fibular fractures in 38 patients were diagnosed to determine whether tibiofibular syndesmosis disruption was present. According to the Lauge-Hansen system, 16 patients had supination-external rotation fractures and 22 had pronation-abduction fractures. Standard non-weight-bearing anteroposterior radiographs and mortise radiographs were evaluated. Furthermore, ankle arthroscopy was performed on all patients. RESULTS: Tibiofibular syndesmosis disruptions were diagnosed in 16 of the 38 patients (42%) by anteroposterior radiography, 21 of 38 patients (55%) by mortise radiography, and 33 of 38 patients (87%) by ankle arthroscopy. All of the patients who were diagnosed with tibiofibular syndesmosis disruption by anteroposterior radiography and mortise radiography were also confirmed by ankle arthroscopy to have injured their tibiofibular syndesmosis. In 12 patients, ankle arthroscopy was the only method used to diagnose the tibiofibular syndesmosis disruption. CONCLUSIONS: Ankle arthroscopy excels in term of the diagnosis ratio for tibiofibular syndesmosis disruption compared with both anteroposterior and mortise radiography. Therefore, we conclude that ankle arthroscopy is necessary for the correct diagnosis of tibiofibular syndesmosis disruption.

Transcriptional regulation of the ATP citrate-lyase gene by sterol regulatory element-binding proteins.

In an attempt to identify unknown target genes for SREBP-1, total RNA from a stable Chinese hamster ovary cell line (CHO-487) expressing a mature form of human SREBP-1a (amino acids 1-487) with a LacSwitch Inducible Mammalian Expression System was subjected to a polymerase chain reaction subtraction method. One of the fragments was found to have 90 and 86% homology with rat and human ATP citrate-lyase (ACL) cDNA, respectively. When Hep G2 cells are cultured under either sterol-loaded or -depleted conditions, expression of the gene is induced approximately 2-3-fold by sterol depletion. To investigate the direct effect of SREBP-1a on transcription, luciferase assays using the promoter of the human ACL gene were performed. These deletion studies indicated that a minimum 160-base pair segment contains the information required for the transcriptional regulation brought about by enforced expression of SREBP-1a. Luciferase assays using mutant reporter genes revealed that SREBP-dependent transcriptional regulation is mediated by two nearby motifs, the SREBP-binding site (a TCAGGCTAG sequence) and the NF-Y-binding site (a CCAAT box). It was confirmed by gel mobility shift assays that recombinant SREBP-1a binds to the sequence. Data from studies with transgenic mice and reporter assays show that the ACL gene promoter is activated by SREBP-1a more strongly than SREBP-2 in contrast to the HMG CoA synthase and LDL receptor gene promoters, which exhibit the same preference for the two factors. Therefore, SREBPs transcriptionally regulates ACL enzyme activity, which generates the cytosolic acetyl CoA required for both cholesterol and fatty acid synthesis.

Sterol regulatory element-binding protein negatively regulates microsomal triglyceride transfer protein gene transcription.

We herein report that mRNA expression of microsomal triglyceride transfer protein (MTP) and its protein synthesis decline in response to sterol depletion in HepG2 cells, and we functionally characterized the MTP gene promoter in an effort to investigate the molecular mechanisms by which MTP gene transcription is regulated. Luciferase assays using truncated versions of the reporter gene revealed that the region at -124 to +33 base pairs of the human promoter contains the elements required for the suppression of transcription by sterol depletion. Enforced expression of an active form of sterol regulatory element-binding protein (SREBP)-1 (amino acids 1-487) or -2 (amino acids 1-481), both of which are activated under sterol-depleted conditions, is able to mimic sterol-mediated down-regulation. Either further truncation of the promoter region or mutation of the putative SREBP-binding sequence (5'-GCAGCCCAC-3', -124 to -116 base pairs) abolishes the sterol- and SREBP-dependent transcriptional regulation. Gel mobility shift assay showed that recombinant SREBP-2-(1-481) is able to bind the sequence. Enforced expression of a truncated form of SREBP-2 (amino acids 31-481), which acts as an inhibitor of transcription of the low density lipoprotein receptor gene because it lacks the transcriptional activation domain, also diminishes the luciferase activity, suggesting that direct binding to the promoter region might be sufficient and that the mechanism by which SREBPs inhibit MTP gene expression is distinct from that for the transcriptional stimulation of sterol-regulated genes. Although the SREBP-binding site overlaps a negative insulin-responsive element, insulin negatively regulates MTP gene expression even when the amount of the active form of SREBPs is quite low under the sterol-loaded conditions, indicating that SREBPs only slightly mediate, if at all, the insulin effects. Overall, we conclude that SREBPs are responsible for regulation of lipoprotein secretion via their control of MTP gene expression. Moreover, our results describe for the first time a novel mechanism by which SREBPs negatively regulate expression of the gene encoding the protein involved in lipid metabolism.

Dental plaque and dietary intakes in schoolchildren in Hawaii.

Plaque formation on the teeth as measured by the number of teeth with a heavy plaque accumulation was found to be influenced by diet. Accumulation of plaque was enhanced by the frequent consumption of food items such as sweet rolls, sweet breads, manapua, and poi. All of these are characterized by their sucrose content and stickiness. However, fruit drinks were shown to have a retarding effect on plaque growth. The information on the amount of plaque had little relationship with the dental caries status of the subjects, whereas it was significantly associated with periodontal health.

Effect of premature loss of deciduous canines and molars on malocclusion of the permanent dentition.

The effect of the premature loss of deciduous canines and first and second molars on malocclusion of the permanent dentition was studied in 255 schoolchildren 11 years of age or older at the most recent examination of the permanent dentition. Malocclusion was evaluated by scoring malalignment (major and minor) and measurement of crowding in the anterior teeth. Children who had a premature loss of one or more canines or molars had a higher frequency of receiving orthodontic treatment of one type or another for the permanent dentition. The likelihood of need of treatment increased with the number of prematurely lost teeth. Children who had lost one or more deciduous teeth through age 9 had a greater than threefold increase in the frequency of orthodontic treatment relative to the control. Of those who did not receive orthodontic treatment, there was no detectable relationship of the premature loss of canines with the malalignment of permanent teeth. However, there was a significant effect of the premature extraction of molars on malalignment especially major malalignment of permanent teeth. No differences were noted in their effects between the first and second deciduous molars. Crowding of the anterior teeth was directly affected by the premature loss of deciduous canines.