A study of elementary particle interactions for high-energy dosimetry.
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Models, Theoretical↗
Biomedical subjects
K Katoh
Publications and source records attributed to K Katoh.
Genetic algorithm-based maximum-likelihood analysis for molecular phylogeny.
A heuristic approach to search for the maximum-likelihood (ML) phylogenetic tree based on a genetic algorithm (GA) has been developed. It outputs the best tree as well as multiple alternative trees that are not significantly worse than the best one on the basis of the likelihood criterion. These near-optimum trees are subjected to further statistical tests. This approach enables ones to infer phylogenetic trees of over 20 taxa taking account of the rate heterogeneity among sites on practical time scales on a PC cluster. Computer simulations were conducted to compare the efficiency of the present approach with that of several likelihood-based methods and distance-based methods, using amino acid sequence data of relatively large (5-24) taxa. The superiority of the ML method over distance-based methods increases as the condition of simulations becomes more realistic (an incorrect model is assumed or many taxa are involved). This approach was applied to the inference of the universal tree based on the concatenated amino acid sequences of vertically descendent genes that are shared among all genomes whose complete sequences have been reported. The inferred tree strongly supports that Archaea is paraphyletic and Eukarya is specifically related to Crenarchaeota. Apart from the paraphyly of Archaea and some minor disagreements, the universal tree based on these genes is largely consistent with the universal tree based on SSU rRNA.
Algorithms↗
Intracerebral hemorrhage after transcatheter thrombolysis of non-occluding superior mesenteric artery thrombosis.
We performed transcatheter thrombolysis on a 64-year-old man with non-occluding superior mesenteric artery (SMA) thrombosis because his severe symptoms could not be controlled with medication. An enhanced computed tomography (CT) scan revealed intramural thrombosis in the SMA. We were concerned that the narrowing of the SMA lumen might progress to complete occlusion, resulting in a high likelihood of mortality. After dissolution of the SMA thrombosis, the original symptoms almost completely disappeared. However, intracranial hemorrhage occurred 8 hr after thrombolysis, requiring surgical intervention. Transcatheter thrombolysis is thought to be a useful treatment for SMA thrombosis, especially in elderly patients with a high operative risk; however, the possibility of intracerebral hemorrhage must be taken into consideration.
Angiography↗
Arsenic residues in well water 36 y after endemic arsenic poisoning.
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Arsenic↗
Distribution of selenium and molybdenum and cancer mortality in Niigata, Japan.
Selenium and molybdenum have inhibitory effects on gastrointestinal carcinogenesis. We investigated the levels of selenium and molybdenum in sediments and mortality from cancers at specific sites in 19 areas of Niigata Prefecture, Japan, and compared these factors. The average concentrations of selenium and molybdenum were 0.44 +/- 0.19 ppm (micrograms/g dry weight; mean +/- standard deviation) and 3.82 +/- 1.03 ppm, respectively. Selenium was not associated significantly with cancer mortality. There were inverse correlations between molybdenum levels and female mortality from cancers of the esophagus (r = -.446, .05 < p < .1) and rectum (r = -.529, p < .05). Molybdenum was correlated positively with female mortality from cancer of the pancreas (r = .603, p < .01). Further investigations are needed for causal interpretation of these results.
Female↗
Virtual CT endoscopy in determining safe surgical entrance points for paranasal mucoceles.
The goal of this work was to evaluate virtual CT endoscopy for determining safe surgical entrance points for paranasal mucoceles. Twelve mucoceles in 11 cases were scanned with helical CT, and multiplanar reconstruction (MPR) and virtual endoscopic images were obtained. After a safe surgical entrance point was determined by MPR images, the entrance point was specified on the virtual endoscopic images. The combination of virtual endoscopic images and MPR images is a suitable method for determining a safe surgical entrance point for simple mucoceles.
Endoscopy↗
A case of abnormal pancreaticobiliary junction evidenced by 3D drip infusion cholangiography CT.
We report a case of abnormal pancreaticobiliary junction (APBJ), in which three-dimensional (3D) drip infusion cholangiography (DIC) computed tomography (CT) was useful to make the diagnosis. The 3D DIC CT clearly demonstrated reflux of the contrast material into the main pancreatic duct as well as a long common channel, dilated biliary tree, and duodenal lumen. Thereby, we could diagnose APBJ. We believe that 3D DIC CT is a valuable method in the evaluation of patients with suspected APBJ.
Aged↗
A phase III randomized study comparing doxifluridine and 5-fluorouracil as supportive chemotherapy in advanced and recurrent gastric cancer.
We conducted a phase III randomized study to investigate effects of supportive chemotherapy with oral doxifluridine (group A, 75 patients) or 5-fluorouracil (group B, 75 patients) in advanced gastric cancer when intensive chemotherapy was not an option. Although there were no significant differences between the groups with regard to survival, hospital-free survival and time to progression, median values of 3 endpoints were superior in group A. Secondary analysis showed that group A patients with prior chemotherapy tended to have longer survival and hospital-free survival and significantly longer time to progression.
Adult↗
The significance of thymidine phosphorylase expression in colorectal cancer.
We measured thymidine phosphorylase activity in colorectal cancer tissue and conducted immunostaining to investigate enzyme expression in the tumor tissue. The results showed a correlation between staining ratio of thymidine phosphorylase and cancer progression as well as a correlation between enzyme activity and staining ratios of cancer cells and stromal cells. Since enzyme activity levels can be judged by staining ratios, this method may be useful for assessing cancer malignancy.
Adenocarcinoma↗
Superselective continuous arterial infusion chemotherapy through the superficial temporal artery for oral cavity tumors.
BACKGROUND AND PURPOSE: High-dose intraarterial chemotherapy with repeated one-shot infusion may be useful for treating head and neck tumors. We evaluated the efficacy of superselective continuous arterial infusion chemotherapy administered via a coaxial catheter system and compared the results with those of subselective catheterization for treatment of oral cavity tumors. METHODS: Forty-nine consecutive patients with tumors of the oral cavity (clinical stage I, 12 cases; stage II, 19 cases; stage III, six cases; stage IV, 12 cases) were treated by arterial infusion chemotherapy. After a guiding catheter was advanced into the superficial temporal artery, superselective catheterization was performed using a coaxial system microcatheter. Superselective catheterization was accomplished in 34 cases, and was unsuccessful in 15, owing to difficulties in performing catheterization or to multiple feeding arteries. In the latter cases, the tip of the catheter was placed near the origin of the feeding arteries (subselective catheterization). RESULTS: Thirty (88%) of 34 patients had a complete response to superselective arterial infusion chemotherapy and two (6%) had a partial response. Twelve (80%) of 15 patients had a complete response to subselective arterial infusion chemotherapy and three (20%) had a partial response. Local recurrence was more frequent after subselective treatment (13%) than after superselective (6%) treatment. CONCLUSION: Superselective continuous arterial infusion chemotherapy may be suitable for local control of oral cavity tumors, with a low rate of recurrence.
Adult↗
Intraosseous neurilemmoma of the mandible.
We report a rare case of intraosseous neurilemmoma of the mandible, with an emphasis on radiographic findings. The tumor, located mainly in the premolar region, presented as an expansive, unilocular, well-defined, radiolucent lesion on plain radiography. No dilatation of the mandibular canal was identified. MR imaging helped to identify the solid nature of the tumor. A biopsy was necessary to make the final diagnosis because of the relatively nonspecific nature of the lesion.
Adult↗
[A thick smear method with cellophane cover slip for detection of helminth eggs in fecalia].
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Ancylostoma↗
An experimental study on cellular immunity and protein-calorie malnutrition.
The effect on cellular immunity of the administration of the non-specific immunopotentiator BCG and/or a streptococcal agent was studied in 90 non-cancer bearing Wistar rats under different nutritional support. The number of immunocompetent cells and the non-specific function of the immunocompetent cells significantly decreased in acute malnutrition. The non-specific immunopotentiator BCG and streptococcal agent activated the peritoneal macrophages, to a remarkable extent, but depressed spleen cell blastoid transformation, thymus index and peripheral lymphocyte count in the starved rat group. In rats who received BCG under intravenous hyperalimentation (IVH), the absolute macrophage counts went down as the quantity of amino-acid administered decreased. The acquired immunodeficiency due to acute malnutrition is evident and the effect obtained with an immunopotentiator is considered to be related to the nutritional status of the host. The adequate administration of protein-calorie is required for the effective use of the immunopotentiator.
Amino Acids↗