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Biomedical subjects

S Hamada

Publications and source records attributed to S Hamada.

At least 307 records · Page 17Linked to original sources
PubMed1989

Cardiac blood-pool scintigraphy using technetium-99m DTPA-HSA: comparison with in vivo technetium-99m RBC labeling.

We performed cardiac blood-pool scintigraphy using technetium-99m diethylenetriaminepentaacetic acid human serum albumin [( 99mTc] DTPA-HSA), a newly developed blood-pool agent, in 31 patients with various heart diseases and evaluated its clinical usefulness in comparison with the conventional in vivo 99mTc red blood cell (RBC) labeling. Excellent cardiac blood-pool images were obtained by [99mTc]DTPA-HSA method. Biodistribution studies showed higher accumulation of [99mTc]DTPA-HSA than that of 99mTc RBC in the lungs and liver, but similar count ratios of the cardiovascular blood pool to whole body between the two methods. In ECG-gated end-diastolic images, no quantitatively significant difference was observed in left ventricular target-to-background ratios between these two methods. Left ventricular ejection fraction (LVEF) calculated by [99mTc]DTPA-HSA MUGA method was correlated well with that by contrast LVEF (r = 0.91). No side effects were observed in any patient. In conclusion, cardiac blood-pool scintigraphy using [99mTc] DTPA-HSA is readily performed by single i.v. injection and useful for the assessment of cardiac function.

Adult↗
PubMed1989

[Cavitating malignant neoplasms in the lung].

Cavitation was found in 8.3% of 96 primary lung cancers, and in 4.5% of 111 metastatic neoplasms. Of 13 excavating lung tumors, seven had adenocarcinoma, 3 squamous cell carcinoma, one anaplastic carcinoma, one hemangioendothelioma, and one malignant melanoma. Primary cavitary lung cancers had relatively thick walls, irregular internal and outer contours, and the location of the cavity was more often central. Excavating pulmonary metastases had smooth outer margin, more often irregular internal contour, and the location of the cavity was central. Among them, four cases had thin-walled cavity. Thin-section CT was useful in the evaluation of the margin of the tumors and the internal contour of the cavities, and in the detection of small cavities in the tumors.

Adenocarcinoma↗
PubMed1989

[Clinical significance of right ventricular ejection fraction in cases with atrial septal defect].

Right ventricular ejection fraction (RVEF) assessed by cardiac radionuclide angiography has been applied to evaluate right ventricular function such as ischemic, valvular and congenital heart disease. Using this modality, previous reports also suggest that there is good correlation between RVEF and mean pulmonary arterial pressure (mPA) from catheterization findings in mitral valvular disease and chronic obstructive lung disease. In this study, cardiac RI angiography were performed on 33 adult patients with atrial septal defect (ASD), RVEF is not so good correlation (r = -0.42) with mPA, but in cases within pulmonary to systemic ratio (Qp/Qs) less than 2.0 limits, there is good correlation between RVEF and mPA (n = 9, r = -0.71). As a conclusion, in ASD, both afterload assessed by mPA and preload assessed by Qp/Qs decrease RVEF.

Adult↗
PubMed1989

[Evaluation of diabetic retinopathy by automated static perimetry].

Decibel values of threshold sensitivity depression of the retina were evaluated in 69 eyes with NIDDM using the Humphrey automated static perimeter. The eyes were classified into three groups: group I (GI) consisting of 32 eyes with no retinopathy or with stages 1 and 2 of simple diabetic retinopathy, group II (GII) consisting of 21 eyes with stage 3 of simple retinopathy or pre-proliferative retinopathy and group III (GIII) consisting of 16 eyes treated by panretinal photocoagulation using an argon laser. The average age in each group was 60 years and all eyes had a visual acuity of over 0.6. As controls, 16 normal eyes were examined. In comparison with the values of the control, the mean of the sum of decibel threshold sensitivity in the macular retina significantly decreased by 5% in GI, 7.8% in GII, and 24.3% in GIII. It was found that the mean of the sum of decibels in the central retina decreased by 8.2% in GI and 15.5% in GII. The sum of decibels in the mid-peripheral retina showed a decrease of 11.4% in GI and 27.5% in GII. In addition, the decibel values of threshold sensitivity of the lower half of the retina tended to decrease more easily than those of the upper half of the retina in the parafoveal and the macular areas. It was also suggested that decibel values of threshold sensitivity of the retina may decrease shortly after PRP in the paramacular area (located about 10 degrees from the fovea) but not in the foveal area.

Aged↗
PubMed1988

The possibility of nonpolypoid carcinogenesis in the large intestine as inferred from frequencies of DNA aneuploidy of polypoid and crater-shaped carcinomas.

DNA ploidy patterns were studied by cytofluorometry in 60 cases of crater-shaped invasive carcinoma and 30 cases of polypoid tumor (severe dysplasia or submucosally invasive carcinoma located in the pedunculated, semipedunculated, or sessile polyp) of the large intestine. The data were compared with 20 cases of intramucosal differentiated (or intestinal type) adenocarcinoma of the stomach, with special reference to their macroscopic shape and frequency of DNA aneuploidy. DNA aneuploidy was found in 77% of the crater-shaped carcinomas and in 17% of the polypoid tumors of the large intestine. The frequencies were significantly different and the frequency gap amounted to 60%. However, 18 of 20 (90%) gastric adenocarcinomas were nonpolypoid in shape, whereas two (10%) were polypoid. DNA aneuploidy was found in 50% of the gastric adenocarcinomas and 56% of the nonpolypoid gastric adenocarcinomas. This value did not differ from the values reported previously for the submucosally invasive and advanced crater-shaped intestinal type adenocarcinomas of the stomach. Biologic characteristics of adenocarcinomas of the large intestine can be compared with those of intestinal type adenocarcinomas of the stomach, because intestinal type gastric adenocarcinoma is surrounded mostly by intestinalized mucosa and considered to arise from the epithelium under induction or progression of intestinal differentiation. Therefore, we inferred that the frequency gap in DNA aneuploidy between the crater-shaped and polypoid tumors of the large intestine implies that in the large intestine approximately 60% of the crater-shaped invasive carcinomas develop from the small nonpolypoid carcinomas.

Adenocarcinoma↗
PubMed1988

DNA distribution pattern of the so-called severe dysplasias and small carcinomas of the colon and rectum and its possible significance in the tumor progression.

The DNA distribution pattern was determined by cytofluorometry in 25 cases of colorectal small carcinoma and the so-called severe dysplasia. The colorectal carcinoma and "severe dysplasia" consisted of four principal stemlines as to DNA ploidy: diploidy, aneuploidy, and their respective polyploidies. These patterns appeared in various combinations in individual neoplasms. DNA distribution of the severe dysplasia was diploid-predominant (11 cases) or aneuploid-predominant (three cases), usually showing mosaicism in various degrees with respective first order polyploidy. Similar DNA distribution patterns also were found in submucosally invasive small carcinomas. The neoplastic cell populations of a higher polyploidy (second or third order), however, occurred only in the submucosally invasive carcinomas (three cases) regardless of their basic ploidy. The mitotic index tended to be higher in the aneuploid-predominant tumors than in the diploid-predominant tumors. In the current observation, there was no significant correlation between the DNA distribution pattern and histologic type of the "dysplasia" or carcinoma. We found that most of the so-called severe dysplasias of the colon and rectum already gained definitive characteristic of carcinoma in the DNA pattern, i.e., ploidy heterogeneity. Therefore, they can be identified as intramucosal carcinomas, distinct from the normal epithelia and adenomas of the colon and rectum.

Aneuploidy↗
PubMed1988

Genetic polymorphism of tear proteins in the rat.

Polymorphism of tear proteins was found by agarose gel electrophoresis among inbred strains of rats. The proteins (RTP-1) are inherited as a single autosomoal trait. The locus was designated Rtp-1 (rat tear protein-1) and it had two codominant alleles (Rtp-1a, Rtp-1b). Although we did not find any recombinant between the Rtp-1 and the Mup-1 loci among 67 backcross progeny, we found 3 strains with the recombinant type between them in 33 inbred strains tested. The results suggest that the Rtp-1 locus is very closely linked with the Mup-1 locus, which belongs to rat linkage group II. RTP-1 proteins strongly reacted with anti-MUP-1 A serum on agarose gel electrophoretograms.

Animals↗
PubMed1988

Electron-microscopic observation of adherence of serotype c Streptococcus mutans to the enamel surface due to glucan synthesis.

Cellular adherence of three strains with water-insoluble glucan (IG)-synthesizing ability and a strain lacking the ability of serotype c Streptococcus mutans to the saliva-coated human enamel surface was examined by scanning (SEM) and transmission (TEM) electron-microscopy. SEM revealed that organisms of all strains used adhered directly to the enamel surface in the absence of sucrose. Cell-to-cell attachment was scarcely observed in the absence of sucrose. Cell-to-cell attachment via amorphous substance on the cell surface was observed by SEM when the strains with IG-synthesizing ability were incubated with the saliva-coated enamel in the presence of sucrose. TEM revealed that cell-associated enzymes of these strains synthesized filamentous and double-stranded fibrillar structures from sucrose. The strain lacking IG-synthesizing ability was unable to induce cell-to-cell attachment in the presence of sucrose, nor was it able to synthesize the amorphous substance. These results indicate that production of IG by cell-associated glucosyltransferase participates in cellular accumulation of serotype c S. mutans.

Bacterial Adhesion↗
PubMed1988

Antitumour effects of streptococcal lipoteichoic acids on Meth A fibrosarcoma.

The antitumour effects of lipoteichoic acids (LTA) extracted from Streptococcus pyogenes were studied in comparison with other streptococcal cellular components. LTA suppressed the tumour growth of both solid- and ascites-type Meth A fibrosarcoma as did the whole cells of S. pyogenes (OK-432). No other cellular components, such as cell wall peptidoglycan, group-specific C-carbohydrate or type-specific M protein, suppressed the growth of Meth A. LTA, but not the other cellular components, induced tumour necrosis factor (TNF) in Propionibacterium acnes-primed mice. LTA had no direct killing effects on Meth A cells. These results indicate that LTA may be an important antitumour component of OK-432 and that one of the antitumour mechanisms by this streptococcal preparation is the induction of TNF.

Animals↗
PubMed1988

Serological properties and immunobiological activities of lipopolysaccharides from black-pigmented and related oral Bacteroides species.

Lipopolysaccharides (LPS) from five species of oral Bacteroides, B. gingivalis strains 381 and ATCC 33277, B. oralis ATCC 33269, B. loescheii ATCC 15930, B. intermedius ATCC 25611 and B. corporis ATCC 33547, were extracted from whole cells by the phenol/water procedure, and subsequently purified by treatment with nuclease and ultracentrifugation. The LPS were composed of hexoses, glucosamine, fatty acids and phosphorus. Heptose and 2-keto-3-deoxyoctonate were not detected. The LPS preparations from B. gingivalis strains 381 and ATCC 33277 presented very similar SDS-polyacrylamide gel electrophoresis patterns when stained with ammoniacal silver. They produced a fused precipitin band against an antiserum to B. gingivalis 381 LPS in immunodiffusion tests. Antisera raised against the LPS from B. loescheii and B. intermedius reacted with the LPS prepared from all the oral Bacteroides strains except those of B. gingivalis. All the LPS preparations were mitogenic for spleen cells of BALB/c (nu/nu) mice, but not for thymus cells from C3H/HeN mice. The LPS induced marked mitogenic responses and polyclonal B cell activation for spleen cells of not only C3H/HeN (LPS responder) mice, but also C3H/HeJ (LPS nonresponder) mice. The mitogenic responses were not suppressed significantly upon addition of polymyxin B to the reaction mixture. These LPS also enhanced interleukin-1 production by murine peritoneal macrophages and mouse cell line J744. 1 macrophages. Hydrolysis of B. gingivalis ATCC 33277 LPS in 1 m-HCl at 100 degrees C for 1 h yielded lipid and polysaccharide. The lipid portion was largely composed of fatty acids and glucosamine, and was mitogenic for spleen cells from C3H/HeJ as well as C3H/HeN mice, while the polysaccharide portion induced no significant mitogenic responses under similar experimental conditions.

Animals↗
PubMed1988

Immunobiological properties of lipopolysaccharides isolated from Fusobacterium nucleatum and F. necrophorum.

Lipopolysaccharides (LPSs) were isolated from Fusobacterium nucleatum ATCC 10953 and F. necrophorum ATCC 25286 by the hot phenol/water procedure. F. nucleatum LPS was composed of 16% (w/w) carbohydrate, 10% (w/w) hexosamine and 40% (w/w) fatty acid, while F. necrophorum LPS was composed of 26% (w/w) carbohydrate, 12% (w/w) hexosamine and 28% (w/w) fatty acid. These LPS preparations induced mitogenic responses in spleen cells of BALB/c, BALB/c (nu/nu) and C3H/HeN mice, and these responses were suppressed by the addition of polymyxin B. The preparations also induced the polyclonal responses of C3H/HeN spleen cells. In addition, enhanced glucose utilization and interleukin-1 production by murine peritoneal macrophages were demonstrated. Neither spleen cells nor macrophages from the 'LPS-nonresponsive' C3H/HeJ mouse were activated by LPSs from the Fusobacterium species.

Animals↗
PubMed1988

Effects of panose on glucan synthesis and cellular adherence by Streptococcus mutans.

The effects of panose on glucan synthesis and sucrose-dependent cellular adherence by Streptococcus mutans were investigated. Panose effectively inhibited glucan synthesis from sucrose by glucosyltransferases from S. mutans strain 6715, but increasing amounts of panose increased the release of fructose from sucrose by the enzymes. On the other hand, production of a series of oligosaccharides of increasing size by the enzymes was markedly enhanced in the presence of panose. These results indicate that panose activates the enzymes and that the inhibition of glucan synthesis by panose is due to the transfer of the glucosyl group of sucrose to panose. Sucrose-dependent adherence of cells of various S. mutans strains to a glass surface was also inhibited by panose.

Bacterial Adhesion↗
PubMed1988

The caries inhibitory effects of GOS-sugar in vitro and in rat experiments.

The caries inhibitory activity of GOS-sugar (panose- and maltose-rich sugar mixture) was examined and compared with that of sucrose, maltose, or glucose in in vitro and in vivo experiments. Streptococcus mutans MT8148R (serotype c) and Streptococcus sobrinus 6715 (g) did ferment GOS-sugar and produce acid in a similar way as with maltose and glucose. However, GOS-sugar could not be a substrate for the glucosyltransferases (GTases) of these mutans streptococci to synthesize the water-insoluble glucan. Also, it significantly inhibited not only the synthesis of water-insoluble glucan from sucrose by the crude GTases but also the sucrose-dependent adherence of these cells to a glass surface. In particular, adherence of growing cells of 6715 was markedly inhibited by the presence of GOS-sugar. GOS-sugar was found to induce significant but minimal dental caries in SPF rats infected with either MT8148R or 6715. Furthermore, the replacement of half of the dietary sucrose content with GOS-sugar resulted in a significant reduction of caries development in rats infected with strain 6715.

Animals↗
PubMed1988

Production of an interleukin-1 inhibitor by cell line P388D1 murine macrophages stimulated with Haemophilus actinomycetemcomitans lipopolysaccharide.

Murine macrophages of the P388D1 cell line stimulated with lipopolysaccharide (LPS) from Haemophilus actinomycetemcomitans Y4 released an interleukin-1 (IL-1) inhibitor, as well as IL-1. Maximal IL-1 activity in culture supernatants was detected after 24 h of culture. On the other hand, IL-1 inhibitor activity reached a maximum level after 72 h of culture. An IL-1 inhibitor was partially purified from the culture supernatant of P388D1 cells stimulated with Y4 LPS for 72 h by ammonium sulfate precipitation, followed by Sephacryl S-200 gel chromatography. A 160-kilodalton peak inhibitory to IL-1 and a 14-kilodalton peak showing IL-1 activity were separated by Sephacryl S-200 column chromatography. The partially purified IL-1 inhibitor significantly suppressed the proliferation of C3H/HeJ murine thymocytes that had been induced with murine and human IL-1 in the presence of a submitogenic dose of concanavalin A. The IL-1 inhibitor more strongly suppressed human recombinant IL-1 beta than human recombinant IL-1 alpha. This inhibitory activity of the partially purified preparation was unaffected by the presence of trypsin inhibitor and the protease inhibitor aprotinin. The IL-1 inhibitor did not exhibit either IL-2 or IL-2 inhibitor activity. The inhibitor suppressed C3H/HeJ thymocyte proliferation induced by IL-1 in the presence of a saturated concentration of IL-2 instead of a suboptimal concentration of concanavalin A. These results indicate that prolonged culture of Y4 LPS-stimulated murine macrophages releases a specific inhibitor of IL-1.

Animals↗
PubMed1988

Suppression of murine macrophage interleukin-1 release by the polysaccharide portion of Haemophilus actinomycetemcomitans lipopolysaccharide.

Lipopolysaccharide (LPS) was extracted from whole cells of Haemophilus actinomycetemcomitans Y4 by the hot phenol-water procedure. LPS was cleaved into its lipid A and polysaccharide moieties by hydrolysis in 1% acetic acid. The major component sugars of the polysaccharide were glucose, heptose, rhamnose, galactose, and fucose. LPS and lipid A from H. actinomycetemcomitans induced the release of interleukin-1 (IL-1) by LPS-responsive C3H/HeN murine peritoneal macrophages and cell line macrophages (P388D1 and J744.1), but not by LPS-nonresponsive C3H/HeJ peritoneal macrophages. The polysaccharide was unable to induce the release of IL-1. It suppressed the IL-1 release from LPS- and lipid A-stimulated macrophages, but not the production of cell-associated and intracellular IL-1. The addition of rhamnose, a sugar component of the polysaccharide, abrogated the inhibitory effect of the polysaccharide on IL-1 release. These results suggest the participation of a lectinlike molecule in IL-1 release.

Cell Line↗
PubMed1988

Enzyme-linked immunosorbent assay of antibody to group A Streptococcus-specific C carbohydrate with trypsin-pronase-treated whole cells as antigen.

We describe the measurement by enzyme-linked immunosorbent assay of antibody to group A Streptococcus C carbohydrate in immunized rabbits and human sera, with trypsin-pronase-treated group A streptococcal whole cells used as the antigen. The optimal concentration of the enzyme-treated whole cells used to coat the wells was 2 x 10(7) cells per well. Rabbit antiserum diluted to 1:12,800 and human serum diluted to 1:1,000 were found to be the optimal concentrations for antibody measurement. Antibody that reacted with enzyme-treated whole cells in rabbit antiserum was absorbed with group A streptococcal whole cells, purified C carbohydrate, and N-acetylglucosamine only. Enzyme-treated whole cells did not react with anti-lipoteichoic acid antibody, and rabbit antiserum did not react with lipoteichoic acid. There was a highly significant correlation between the anti-C carbohydrate antibody titrated with enzyme-treated whole cells and that with purified C carbohydrate as antigen. The correlation coefficient for the immunoglobulin M (IgM) antibodies was r = 0.75, and for the IgG antibodies it was r = 0.77. When the IgG antibody titers to the enzyme-treated whole cells of the sera of patients with acute poststreptococcal glomerulonephritis and rheumatic fever were compared with those of sera of healthy individuals, the sera of patients with poststreptococcal sequelae had significantly higher titers than did healthy individuals. Although anti-C carbohydrate antibody in human sera mostly belonged to the IgG2 subclass, there was anti-C carbohydrate antibody that belonged to the IgG3 subclass in a certain percentage of patients with rheumatic fever and acute poststreptococcal glomerulonephritis.

Adolescent↗