Biomedical subjects
Publications and source records attributed to K Sasaki.
Plasmon-loss imaging was applied to chemical mapping during an in-situ heating experiment. The technique was applied to observation of vibration of a Si/SiO2 interface which took place during reduction of SiO2 at high temperature. The chemical maps of Si and SiO2 were recorded dynamically using a conventional TV-VTR system at a time resolution of 1/30 s.
Fatal cases of malaria are rare in Japan. We report a case of a 47-year-old Japanese man with Plasmodium falciparum malaria. The patient was examined because of fever and headache after a trip to Africa. He was diagnosed with malaria. Chemotherapy begun on day three decreased the percentage of infected red blood cells (RBC) from 25% to 2%, but the patient fell into coma on the same day. The patient was considered brain dead for 3 days before he died, and he was autopsied on day nine. Brain hemispheres were preserved and swollen with meningeal congestion. The ventral area of the pons and medulla oblongata were softened, and the tonsils of the cerebellum were softened and herniated. The spleen was blackish, enlarged and showed a small infarction. The liver was yellowish and enlarged. Many infected RBC were seen in the capillaries of the brain and malaria pigments were seen in the spleen and liver. DNA of P. falciparum was detected by polymerase chain reaction from paraffin-embedded brain materials, however, the DNA could not be detected in other organs. Besides malaria, the patient had latent primary thyroid cancer, which was a small and invasive papillary carcinoma.
To determine whether p53 expression is different in intestinal and diffuse types of gastric carcinoma, we investigated p53 immunohistochemical expression in 178 primary gastric carcinomas. Overexpression of p53 was observed in 50 out of 100 intestinal-type tumors (50.0%) and in 27 out of 78 diffuse-type tumors (34.6%). A significant difference was found in the timing of p53 overexpression between the two types of carcinomas. Overexpression of p53 occurred often in the early stage of intestinal-type tumors, and there was no significant difference in expression between early and advanced cancers. In contrast, p53 overexpression did not occur often in the early stage of diffuse-type tumors, but it increased progressively as the tumor advanced. Analysis of patient survival revealed that p53 overexpression correlates significantly with a poor prognosis in diffuse-type gastric carcinoma (P = 0.003) but not in intestinal-type. Multivariate analysis showed that only pathological stage was an independent prognostic indicator. Our results suggest that p53 overexpression plays a different role in tumor carcinogenesis and progression of these two types of gastric cancers.
Nonsteroidal anti-inflammatory drugs (NSAIDs), which are used widely to manage pain, are known to inhibit cyclooxygenase, but details of the mechanisms of NSAID action remain unclear. We investigated the ability of three NSAIDs (indomethacin, loxoprofen, and etodolac) to eliminate and inhibit free radicals. Superoxide scavenging activity of these NSAIDs was measured in vitro by electron spin resonance spectrometry using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as a spin trap. Electron spin resonance demonstrated that formation of superoxide-DMPO spin adduct was completely inhibited by two nonselective cyclooxygenase inhibitors, indomethacin (3 mmol) and loxoprofen (3 mmol). The electron spin resonance study also demonstrated that the formation of superoxide-DMPO spin adduct was strongly inhibited by a selective cyclooxygenase-2 inhibitor, etodolac, in a concentration-dependent manner. These results indicate that NSAIDs, including indomethacin, loxoprofen, and etodolac, have direct superoxide scavenging activity.
Melanocytic naevi are common and they are often removed for cosmetic purposes. In recent years, both the normal mode ruby laser and the Q-switched ruby laser have been used, either alone or in combination, for the removal of congenital melanocytic naevi. However, their success was restricted to partial lightening and incomplete histological clearance. We report a new approach, with combined use of normal mode and Q-switched ruby lasers, that improves the effectiveness of the laser removal of pigmentation in congenital melanocytic naevi.
BACKGROUND: The frequency and characteristics of cortical cataract localization within a dilated pupillary area were investigated in a population-based cataract epidemiological survey performed in the city of Reykjavik in Iceland. MATERIALS AND METHODS: Among 1045 randomly selected individuals, the right eyes of 277 persons with mild cortical lens opacification (Grade I) were selected for our study. The localization of cortical cataracts was examined using retroillumination images, which were divided into 56 circular and radial sections, and calculations were made of the percentages for each opacified area. A questionnaire was used to record the number of hours spent outdoors during week days, the time of the day and whether the subjects wore spectacles, sunglasses or hats when outside. RESULTS: The percentage of cortical opacification was significantly higher in the lower nasal quadrant than in all other quadrants (p < 0.05). Furthermore, the percentage of opacification localized in the lower nasal quadrant was higher in individuals with a longer history of outdoor activity than those without (p < 0.05). The percentage of opacification in individuals, who have had the habit of wearing sunglasses for outdoor activities lasting longer than half an hour during weekdays in their 20's and 30's was lower in all quadrants and statistically significantly lower in the upper temporal quadrant (p < 0.05) compared to those not wearing sunglasses. CONCLUSION: This suggests that wearing sunglasses is effective in preventing the development and/or progression of cortical cataracts.
Two young adults underwent resection of large hypervascular vestibular schwannomas (acoustic neuromas) via two-stage surgery. The first patient, a 27-year-old woman with hydrocephalus, had a large hypervascular vestibular tumor in the left cerebellopontine angle (CPA) supplied by the left anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA). The second patient, a 34-year-old woman, had a large AICA-supplied hypervascular vestibular tumor in the left CPA that displaced the brain stem significantly. At the initial stage, only the lateral aspect of the tumor was debulked due to excessive bleeding from the tumor bed. Angiography 1 or 2 months after the initial operation showed that the tumor was hypovascular. At the second stage, the remnant medial aspect of the tumor was relatively avascular and nonadherent to the brain stem. Without blood transfusion during the second stage, the tumor was removed totally in the first patient and subtotally in the second patient. Pathological examination revealed that dilatated blood vessels were prominently increased at the first surgery; however, at the second surgery, the number of blood vessels had decreased, showing necrosis and degeneration. Although there are no absolute indications for the staged resection of vestibular schwannomas, this procedure may represent one of the safest options for these difficult lesions in young adults.
BACKGROUND: The purpose of the current study was to determine how the location of the infarct-related lesion (IRL) and the degree of stenosis during the acute and chronic phases of infarction might affect left ventricular (LV) function in patients with acute anterior wall myocardial infarction. METHODS: Ninety consecutive patients with a first single-vessel anterior wall myocardial infarction (male/female ratio 75:15, mean age 60+/-9 years) underwent coronary angiography (CAG) immediately and 1 month after infarction. Patients were grouped according to IRL location (proximal [Coronary Artery Surgery Study (CASS) No. 12] or distal [CASS No. 13] to the first diagonal branch of the left anterior descending artery) and according to the severity of stenosis at 1 month (severe stenosis [IRL >75%] and mild stenosis [IRL < or =75%]). At the time of infarction and 1 month and 1 year after infarction, total wall motion index (TWMI), left ventricular end-diastolic dimension (LVDd), left ventricular end-systolic dimension (LVDs), and fractional shortening (FS) were determined. RESULTS: TWMI was greater and FS was lower for CASS No. 12 lesions than for CASS No. 13 lesions. CASS No. 12 lesions were associated with a greater LVDd at 1 year and a greater LVDs throughout 1 year of observation. The patients with mild stenoses had significant improvements in TWMI and FS over time, whereas those with severe stenoses showed no improvement. Multivariate analysis showed that the independent factors predicting left ventricular function were IRL location at CASS No. 12, initial TIMI 0-1 flow in the IRL at emergency coronary artery graft, and the presence of a severe stenosis at 1 month. CONCLUSIONS: In patients with severe stenoses at 1 month at CASS No. 12, left ventricular functional recovery is delayed and the left ventricular chamber is enlarged. In patients with CASS No. 13 lesions, left ventricular function is preserved well, regardless of the severity of residual stenosis.
Serum amyloid A (SAA) has been characterized as an inflammatory marker in many species. In this study, we have developed and characterized monoclonal antibodies (MAbs) against feline SAA (fSAA) derived from culture hybridomas. These hybridomas were produced from the fusion of Balb/c-derived myeloma s/p20-Ag14 and splenocytes from mice immunized with purified recombinant feline SAA (rfSAA). Six hybridomas secreting MAbs, M2, M5, M7, M8, M13, and M15, were selected and subcloned on the basis of their specificity to rfSAA by enzyme-linked immunoabsorbent assay (ELISA), and confirmed based on their specificity to rf-SAA by immunoblot analysis. Out of six clones, two clones (M5 and M7) showed higher reactivity with rf-SAA, and were selected for further analysis of ELISA additivity and Western blot cross-reactivity tests. As a result, M5 and M7 clones recognized the same or excessively near epitopes on rfSAA and reacted with rfSAA, fSAA and equine recombinant SAA, but showed no reaction with human recombinant SAA. Because of their specificity, these MAbs may be usefully applied in studying the measurement of SAA concentration in cat serum.
The function of Epstein-Barr virus (EBV)-specific cytotoxic T cells is disturbed in rheumatoid arthritis (RA) patients but the mechanism for this disturbance has remained unknown. In a recent study searching for the causative gene of X-linked lymphoproliferative syndrome, the gene possibly linked to EBV-specific cytotoxic T cells or NK cell-mediated cytotoxic activity to EBV-infected cells was discovered, and its product is now referred to as signaling lymphocytic-activation molecule-associated protein (SAP) or Src homology 2 domain-containing protein (SH2D1A). In the present study, we attempted to investigate the involvement of the SAP gene in RA using a quantitative real-time PCR; the expression level of SAP transcripts in peripheral leukocytes or T cells was examined for patients with RA. The expression level of SAP transcripts in peripheral leukocytes of 21 RA patients was significantly lower than that of 13 normal individuals (P = 0.0007), four patients with palindromic RA, 11 with inactive systemic lupus erythematosus (SLE) or 17 with chronic renal diseases. The decreased expression of SAP transcripts in RA patients was also observed in peripheral CD2(+) T cells compared with normal individuals. There was no mutation in the coding region of SAP cDNAs derived from peripheral leukocytes of five RA patients. The decreased expression of SAP transcripts in peripheral leukocytes or T cells of RA patients might lead to the failure of the immune system to eliminate the EBV-infected synovial lining cells in joints of RA patients. Our findings have suggested that decreased expression of the SAP gene might be involved in the onset or progress of RA.
In the manufacture of semiconductor microelectronic devices, a p-n junction is formed usually by implanting a high concentration of impurity into a less heavily doped region and then heat annealing. A Si/Si p-n junction test sample has been made following the above practical process and thinned for electron holographic observation by using argon ion-milling. From the reconstructed phase image, the phase shift induced by potential drop across p-n junction can be seen clearly. To characterize quantitatively this potential drop, the mean inner potential V0 of silicon was measured precisely by electron holographic method. By measuring 25 different crystalline silicon spheres with diameter ranging from 40 to 170 nm, an average result of V0 = 12.16 +/- 0.83 V was obtained. By using this V0 value, a quantitative measurement yields the potential drop approximately 0.70 V, which is reasonably consistent with expected Si/Si junction parameter. The thickness of electric dead layer in depletion region produced from this measuring is approximately 20 nm on each sample surface.
Some naturally occurring nuclear localizing signals (NLSs) and some artificially designed peptides were covalently conjugated by solid phase fragment condensation (SPFC) method. These DNA-peptide conjugates showed enhanced permeability into cells as well as enhanced hybrid stability with ssDNA and dsDNA, and also higher resistance against nuclease digestion.
Class III plant peroxidase (POX), a plant-specific oxidoreductase, is one of the many types of peroxidases that are widely distributed in animals, plants and microorganisms. POXs exist as isoenzymes in individual plant species, and each isoenzyme has variable amino acid sequences and shows diverse expression profiles, suggesting their involvement in various physiological processes. Indeed, studies have provided evidence that POXs participate in lignification, suberization, auxin catabolism, wound healing and defense against pathogen infection. Little, however, is known about the signal transduction for inducing expression of the pox genes. Recent studies have provided information on the regulatory mechanisms of wound- and pathogen-induced expression of some pox genes. These studies suggest that pox genes are induced via different signal transduction pathways from those of other known defense-related genes.
The effect of the oviductal environment on gene expression in 2-cell mouse embryos was examined with mRNA differential display. Embryos used for experiments were cultured in modified Whitten medium with or without oviductal tissue until late 2-cell stage. The results of sequencing indicated that the genes for ATP synthase (ATPase 6), S:-adenosylmethionine decarboxylase (S:-AMDC) and nuclear autoantigenic sperm protein (NASP) were differentially expressed in embryos cultured in the oviductal environment (nonblocking culture condition). The ATPase 6 gene is encoded by mitochondrial DNA and is essential for the production of ATP. This indicates that the expression of ATP synthesis-related genes at the 2-cell stage may be required to maintain normal development in vitro. S:-Adenosylmethionine decarboxylase decarboxylates adenosylmethionine, which is a substrate of DNA methylation. The expression of S:-AMDC may be responsible for the low level of methylation of preimplantation development. As NASP is a histone-binding protein that is thought to be testis and sperm specific, its function in embryos remains unclear. On the other hand, the Tcl1 gene and a novel gene, the c-1 gene, were strongly expressed in embryos cultured without oviductal tissue (blocking culture condition). The expression patterns of these genes are quite similar. However, the detailed functions of these genes in embryos remain to be determined.
OBJECTIVE: The present retrospective study was undertaken to prove the reliability of the aspect ratio (aneurysm depth to aneurysm neck width) for predicting an aneurysmal rupture. The aspect ratio is considered a better geometric index than aneurysm size for determining the intra-aneurysmal blood flow. METHODS: We measured the aspect ratios and the sizes of aneurysms, as determined by examining angiographic films magnified 1.4x, in 129 patients with ruptured aneurysms and in 72 patients with 78 unruptured aneurysms. After categorizing the aneurysms into four groups on the basis of their locations (aneurysms of the anterior communicating artery, middle cerebral artery, internal carotid artery-posterior communicating artery [ICA-PComA], and other aneurysms), a statistical analysis of ruptured and unruptured aneurysms was performed. RESULTS: The mean aneurysm size was found to be statistically significant in the aneurysms at the ICA-PComA and in locations excluding the anterior communicating artery, the middle cerebral artery, and the ICA-PComA. However, the mean aspect ratio was statistically significant at all four locations. In patients with ruptured aneurysms, no ruptured aneurysms with an aspect ratio of less than 1.0 were found. The distribution of the ruptured group versus the unruptured group with an aspect ratio of less than 1.6 at each location was 13 versus 79%, respectively, at the anterior communicating artery, 11 versus 58% at the middle cerebral artery, 11% versus 85% at the ICA-PComA, and 7 versus 81% at other locations. CONCLUSION: The aspect ratio between ruptured aneurysms and unruptured aneurysms was found to be statistically significant, and almost 80% of the ruptured aneurysms showed an aspect ratio of more than 1.6, whereas almost 90% of the unruptured aneurysms showed an aspect ratio of less than 1.6. This study therefore suggests that the aspect ratio may be useful in predicting imminent aneurysmal ruptures.
The non-random amplification of DNA at 9p23 - 24 observed in various types of human cancers, including esophageal squamous cell carcinomas (ESCs), may reflect the locations of important tumor-associated genes. Our previous studies using ESC cell lines defined an amplicon in this region and identified a novel gene, GASC1, as a target of the amplification. Since different regions within the same chromosome arm are often involved in amplification in a syntenic or non-syntenic manner, we characterized the amplicon at 9p23 - 24 in 35 ESC cell lines (29 KYSE series and 6 YES series), and examined possible involvement of non-syntenic amplifications at 9p23 - 24 in 32 primary ESCs. Our results clearly indicated that two target regions for DNA amplification exist at 9p23 - 24; the major amplicon contains GASC1, and the minor one harbors a transcription factor, NFIB, centromeric to the GASC1 locus.
We have analyzed DNA sequence copy number aberrations (DSCNAs) and DNA ploidy by using comparative genomic hybridization and laser scanning cytometer in gastric carcinomas (GCs) to elucidate the genomic aberrations in relation to clinicopathological parameters. Thirty-two out of 33 cases showed one or more DSCNAs with a mean number of 11.7 per tumor. High-level gains were detected at 2p, 3q, 6p, 7p, 7q, 8q, 12p, 13q, 19q, and 20q. Frequency of gross genomic abnormalities and chromosome regions that have genomic aberrations were similar in both intestinal- and diffuse-type GCs, except aberrations at 8p, 9p, 12q, and 20q. The overall number of DSCNAs was significantly greater in DNA aneuploid tumors than that in DNA diploid tumors. We detected genomic aberrations characterized by histological subtype, tumor location, and DNA ploidy status: gain of 20q and losses of 8p and 9p in intestinal-type GCs, gains of 8p and 12q in diffuse-type GCs, gain of 20q in the lower third GCs, and loss of 5q, 9p, 10q, 16q, and 18q in DNA aneuploid GCs. Furthermore, 5q loss is associated with DNA aneuploidy (P = 0.0001) or the total number of losses (P = 0.001), gain + losses (P = 0.004), and high-level gains (P = 0.001) in GCs. Among these loci, chromosome 8p was unique. Gain of 8p was more common in diffuse-type GC, whereas loss of 8p was more frequently detected in intestinal-type GC. In conclusion, we describe chromosomal regions of 5q, 8p, and 20q, which are of interest for further investigation of GCs.
The tissue distribution of a gallium-porphyrin photo- and sono-sensitizer, 7,12-bis(1-decyloxyethyl)-Ga(III)-3,8,13,17-tetramethylporphyrin-2,18-dipropionyldiaspartic acid, ATX-70, was pharmacokinetically examined in tumor-bearing mice. The drug was administered intravenously to CDF(1) mice implanted with Colon 26 carcinoma. Blood and tissue samples were collected for up to 72 h after administration. The drug concentration was determined by high-performance liquid chromatography (HPLC) with fluorescence detection. ATX-70 was found to accumulate in tumors at a relatively high concentration that peaked between 2 h and 6 h after administration. However, modest concentrations of ATX-70 also remained in healthy tissues for up to 6 h. We examined the distribution of ATX-70 in the tumor in comparison with other tissues from the viewpoint of minimizing possible side effects of laser or ultrasound exposure while maintaining the treatment effect. About 24 h after administration, the tumor / plasma concentration ratio peaked, and relatively high tumor / skin and tumor / muscle concentration ratios were seen.