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S Hamada

Publications and source records attributed to S Hamada.

At least 343 records · Page 19Linked to original sources
PubMed1987

Serial section method for cytofluorometric determinations of the DNA content of component cells of the human cochlea.

We describe a method for measuring the DNA content of the component cells of the organ of Corti using serial sections of human cochleae obtained at autopsy. Cochleae were fixed in Carnoy's solution and embedded in Acrytron E, a water-miscible methacrylate resin. A procedure was developed to reduce the background fluorescence in methacrylate-embedded sections; the resin was pretreated with ion-exchange resin (Amberlite IRA-410). Experiments showed that pretreatment reduce the background fluorescence practically to zero. Seventy 3 microns-thick serial sections were prepared on fluorescence free glass slides and stained with azocarmin G and acriflavine-Feulgen. After postirradiation using blue excitation light, the amount of Feulgen-DNA present in the target nucleus in each section was determined using a microfluorometer. The amount of DNA in the entire nucleus was determined by adding together the DNA content of the segments of the nucleus. The characteristic appearance of the organ of Corti made it easy to detect these cells; under green excitation light the cells of this organ exhibited red cytoplasmic azocarmin-G fluorescence. Due to the relatively wide internuclear spaces, cytofluorometry fo individual nuclei could be performed without interference from the neighboring cells. Our technique using serial sections allowed us to measure the DNA content of individual cells and obtain histological information about particular cells and their neighboring cells. Several polyploid cells were found among the Hensen's cells in the cochlea, while all other component cells of the organ of Corti were diploid.

Cell Nucleus↗
PubMed1987

Haptenated streptococcal antigens elicit either T cell-dependent type 1 or T cell-independent type 2 immune responses.

Antigens of Streptococcus mutans 6715 (alternatively designated serotype g Streptococcus sobrinus), including whole cells (WC g), cell walls (CW g), peptidoglycan (PG g) and serotype carbohydrate (Ml g) were coupled with trinitrophenyl (TNP), and the nature of the immune response to each immunogen was determined in normal and X-linked immunodeficient (xid) murine spleen cell cultures. Responses to TNP-WC g, -CW g and -PG g and to the classical type 1 antigen TNP-Brucella abortus occurred in both xid and normal splenic cultures, while TNP-Ml g only triggered immune responses in normal spleen cell cultures, suggesting that the former three antigens are type 1 and the latter type 2. Further support for the type 2 nature of TNP-Ml g was the finding that Peyer's patch cell cultures from both xid (which contain mature B cells) and normal mice supported responses to TNP-Ml g and TNP-Ficoll, while xid splenic cultures failed to support responses to either type 2 antigen. The three type 1 TNP-S. mutans antigens induced responses in nude spleen cell and in purified splenic B cell cultures, but required T cells for in vitro responses to lower doses of immunogen. On the other hand, TNP-Ml g induced anti-TNP PFC responses at several antigen concentrations in purified B cell cultures, without requirement for added T cells. These studies show that the intact S. mutans cell, as well as CW g and PG g, acts as a T cell-dependent (TD) type 1 antigen, while the serotype carbohydrate (Ml g) induces a T cell-independent (TI) type 2 response. Thus, the intact bacterium is a TD type 1 antigen, whereas its purified components are either type 1 or type 2 antigens and differ significantly in terms of their T cell dependence.

Animals↗
PubMed1987

Serological relationships between serotype-III Streptococcus sanguis and Lancefield group-H streptococci.

Certain strains of Streptococcus sanguis and group-H streptococci have been shown to have similar physiological properties and serological specificities. Serological studies revealed that serotype-III S. sanguis shared a common antigen with the so-called "British" group-H streptococci, but not with the "American" group-H streptococci. Serotype-III antigen was extracted in cold 5% trichloroacetic acid from isolated cell walls of S. sanguis ATCC 10558, and purified chromatographically. The purified serotype-III antigen consisted of neutral and amino sugars and some phosphorus, and was negatively charged. Hapten inhibition of the quantitative precipitin reaction between serotype-III antigen and antiserum indicated the strong possibility of alpha-glucosidic linkages being an immunodeterminant of the antigen.

Antigens, Bacterial↗
PubMed1987

Ultrastructure of extracellular polysaccharides produced by serotype c Streptococcus mutans.

The ultrastructure of extracellular polysaccharides produced in colonies by two clinical isolates and that of a nitrosoguanidine-induced mutant of serotype c Streptococcus mutans with different polysaccharide-synthesizing abilities were compared electron-microscopically. A large amount of polysaccharide was produced from sucrose by colonies of typical serotype c strain MT8148R and a clinical variant MT6801R with an enhanced fructan-synthesizing ability. Transmission electron-microscopy (TEM) revealed that the polysaccharides consisted of three structural components, i.e., globular, single-stranded filamentous, and double-stranded fibrillar structures. These structures were ascribed to production of fructan, water-soluble glucan, and water-insoluble glucan, respectively. On the other hand, two kinds of structures, a globular body and an amorphous substance, were observed by scanning electron-microscopy (SEM). The former was composed of fructan, while the latter contained a mixture of water-soluble and water-insoluble glucans which formed filamentous and double-stranded fibrillar structures under TEM. Very small quantities of polysaccharides were formed in colonies of mutant NG7183, which was derived from S. mutans MT6801R. This strain was found to possess low glucan- and no fructan-synthesizing abilities. The polysaccharides produced in colonies of mutant NG7183 were composed only of filamentous and double-stranded fibrils under TEM. A small amount of amorphous substance was observed by SEM in colonies of NG7183.

Dextranase↗
PubMed1987

Coronary arteritis in mice after systemic injection of bacterial cell wall peptidoglycan.

We examined cell wall peptidoglycan (PGL) derived from group A streptococcus and other bacteria for possible induction of coronary arteritis in mouse strains. The histological finding of the main trunk of the coronary arteries of BALB/c, DBA/1J, C57BL/6 and DBA/2 mice, which were given an intravenous injection of sonicated PGL fragments of st. pyogenes at 500 micrograms per mouse 4 times at intervals of 1 week, showed diffuse cellular infiltration in the vascular wall as well as perivascular space. Marked hyperplasia of the endothelial cells was noted and necrosis of the medial smooth muscle of the coronary artery also was observed. The elastica stain clearly demonstrated fragmentation and degeneration of the elastic fibers. The histological change of the originating site of the aorta also noted swelling or hyperplasia of the endothelial cells and perivascular cellular infiltration. PGL fragments of st. mutans, st. sanguis and s. aureus did not cause any heart lesions. Coronary arteritis induced by st. pyogenes PGL could be very useful as an experimental animal model of Kawasaki's disease.

Animals↗
PubMed1987

Characteristics of colorectal epithelia and adenomas as revealed by DNA cytofluorometry.

Human colorectal normal epithelia and tubular adenomas were studied by DNA-cytofluorometry using free cell nuclei isolated from formalin-fixed and paraffin-embedded specimens. All the normal epithelia (30 cases) showed low proliferative activity, no polyploid cells and no aneuploid cell clones at any age in either sex. The mean diploid G1/G0 fraction (DF) of the normal epithelia was 95.9%. The adenomas, on the other hand, showed increased proliferative activity usually in accordance with the grade of atypia. The mean DF values of the adenomas with mild atypia (31 lesions) and moderate atypia (21 lesions) were 89.4% and 85.6%, respectively. The adenomas, irrespective of their grade of atypia, occasionally showed low proliferative activity, while in the adenomas adjacent to a carcinoma, the proliferative activity was relatively high even though their atypia was mild. Neither polyploid cells nor aneuploid cell clones were found in the adenomas. Therefore, polyploid and aneuploid cell populations are characteristics of carcinoma of the colon and rectum, and this criterion should be useful in investigations of the genesis of carcinoma in the human colorectal mucosa.

Adenoma↗
PubMed1987

Papillary carcinoma of the thyroid. A histochemical, immunohistochemical and ultrastructural study with special reference to the follicular variant.

Twenty-one papillary thyroid carcinomas (PTCs), grouped into predominantly papillary (14 cases), predominantly follicular (5 cases), and extremely follicular, i.e., follicular variant (2 cases) types, were studied in comparison with three cases each of follicular lesions including follicular carcinoma, follicular adenoma, adenomatous goiter and Graves' disease. Histochemical, immunoperoxidase, and electron microscopic analyses demonstrated no remarkable differences between the predominantly papillary and predominantly follicular PTCs, but the presence of common characteristics distinct from those of the follicular lesions. These two types of PTCs showed less glycogen, more mucoid material, more epidermal keratin, less thyroid hormone with relative predominance of T3 over T4, and more interdigitating reticulum cells (IDCs) than most of the follicular lesions. Ultrastructurally, the tumor cells of these PTCs had markedly irregular nuclei, a vesicular chromatin pattern, and small basally located lysosomes, in contrast with the cells in the follicular lesions which had smooth round nuclei, more heterochromatin, and apical or dispersed lysosomes of various sizes. The follicular variant PTCs showed some mixed features, such as glycogen in the follicular portion and mucoid material in metastatic papillary foci, positive keratin and IDCs but greater amounts of thyroid hormone, and a rather intermediate type of ultrastructure with only mildly irregular but vesicular nuclei and large apical as well as small basal lysosomes. These findings cytologically support the WHO definition of papillary carcinoma that includes tumors with variable mixtures of papillary and follicular patterns. However, separate consideration may be necessary with regard to the follicular variant.

Adenocarcinoma↗
PubMed1987

A new polymorphic pepsinogen locus (Pg-2) in the rat (Rattus norvegicus).

Only two types of pepsinogens, which are products of the Pg-1 locus, are present in rat urine. In gastric mucosa, however, additional pepsinogen isozymes are expressed. We have found a polymorphism for rat gastric mucosa pepsinogen using agarose gel electrophoresis. Some inbred rat strains expressed a pepsinogen band, while others did not. The trait was found to be controlled by a single autosomal locus. We tentatively designated the locus as Pg-2 with two alleles, Pg-2a for the one controlling presence of the band and Pg-2o for the one controlling absence. Linkage analysis using BN and TM strains revealed that Pg-2 was closely linked to Pg-1 (3.7 +/- 1.8 cM), and that it did not belong to LG I (Hbb and p), LG II (Acon-1 and Mup-1), LG IV (Hao-1 and Svp-1), LG V (Es-1 and Es-3), LG VI (Gc and h), LG IX (RT1), LG X (Fh and Pep-3), nor a LG containing Ahd-2 (as yet undetermined).

Animals↗