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Biomedical subjects

S Handa

Publications and source records attributed to S Handa.

At least 343 records · Page 19Linked to original sources
PubMed1984

Coomassie brilliant blue staining of lipids on thin-layer plates.

Coomassie brilliant blue staining of lipids on silica gel thin-layer chromatography plates is described. This stain proved to be useful for the wide-range detection of simple and complex lipids on thin-layer plates. It can stain several classes of lipids, including cholesterol, cholesterol esters, glycerides, phospholipids, ceramides, and neutral and acidic glycosphingolipids. It stains the spots evenly without a corrosive reagent, and is simple to use and suitable for storage. The visual detection limits of this stain for lipids were 0.05 to 0.5 microgram.

Chromatography, Thin Layer↗
PubMed1984

Effect of modification of sialic acid on enzymic hydrolysis of gangliosides GM1 and GM2.

In order to understand the mechanism of action of the activator proteins for the enzymic hydrolysis of GM1 (GM1-activator; Li, S.-C. and Li, Y.-T. (1976) J. Biol. Chem. 251, 1159-1163; for ganglioside designations, see Svennerholm, L. (1963) J. Neurochem. 10, 613) and GM2 (GM2-activator; Li, S.-C., Hirabayashi, Y., and Li, Y.-T. (1981) J. Biol. Chem. 256, 6234-6240), we have studied the effect of chemical modifications of GM1 and GM2 on their susceptibility to the activator-assisted enzymic hydrolysis. Chemically modified GM1 and GM2 were prepared by methyl esterification (Me-GM1 or Me-GM2) and reduction (HO-GM1 or HO-GM2) of the -COO- group of the sialic acid. Me-GM1 and HO-GM1 could be hydrolyzed by human hepatic beta-galactosidase in the presence of GM1-activator at rates comparable to that of the native GM1. However, in contrast to native GM2, Me-GM2 and HO-GM2 were resistant to the hydrolysis by human hepatic beta-hexosaminidase A in the presence of GM2-activator. When GM2-activator was replaced by sodium taurodeoxycholate, the native GM2 and both modified GM2 could be hydrolyzed by beta-hexosaminidase A. These results suggest that the carboxyl function of sialic acid in GM1 is not vital for beta-galactosidase or GM1-activator to carry out the cleavage of the terminal Gal. In the case of GM2 hydrolysis, the carboxyl function of sialic acid is involved in the interaction with GM2-activator. Our results also indicate that the mode of action of GM1-activator is different from that of GM2-activator and that the action of GM2-activator is different from that of sodium taurodeoxycholate.

Brain↗
PubMed1984

Application of field desorption and secondary ion mass spectrometry for glycolipid analysis.

Field desorption (FD) and secondary ion mass spectrometry (SI-MS) mass spectra of several glycolipids are presented to demonstrate their potential for the analysis of glycolipids. FD and SI-MS give useful information on molecular weight, ceramide structure and sugar sequence. In general, FD provides clearer fragment ion peaks for the analysis of sugar sequence than SI-MS. For underivatized acidic glycolipids such as gangliosides, sulfatide and seminolipid, SI-MS provides quasimolecular ions which are hardly produced by FD. In contrast to underivatized gangliosides, permethylated samples give molecular ion species of high intensity in both FD and SI-MS, but no fragment ions pertinent to carbohydrate sequence could be observed in FD spectra. SI-MS spectra of permethylated samples provide good information on sugar chain structure. Thus FD and SI-MS mass spectra complement each other, and the combination of these ionization methods will provide powerful tools for glycolipid analysis.

Animals↗
PubMed1984

Glycosphingolipids of porcine pancreas.

Neutral and acidic glycosphingolipids were purified from porcine pancreas by chromatography on columns of DEAE-Sephadex and Iatrobeads. The chemical structures of the purified glycolipids were determined by carbohydrate analysis, methylation analysis, enzyme treatment, fatty acid analysis, NMR and IR. The major glycolipid of porcine pancreas was Gal(alpha,1-4)Gal(beta,1-)ceramide. Gangliosides GM3 and GD3 were major acidic components and galactosylceramide 3-sulfate was also found.

Animals↗
PubMed1984

Modification of sialic acid carboxyl group of ganglioside.

A simple and quantitative method for the modification of sialic acid carboxyl group in ganglioside is described. Methyl iodide was added to the ganglioside in dimethylsulfoxide. The reaction was completed quickly at room temperature, giving the methyl ester with practically no by-products. Reduction of the methyl ester was achieved by sodium borohydride. These modified gangliosides were chemically characterized. Reduced GM1 has a strong antigenicity compared with the original GM1, and it raised high titer antisera which did not crossreact with the original GM1 nor with its methyl ester. Peanut agglutinin, which binds strongly to asialo GM1 but weakly to GM1, bound to the methyl ester of GM1 and reduced GM1. Cholera toxin, which is specific for GM1, also reacted with the methyl ester of GM1 and reduced GM1 to a certain extent.

Animals↗
PubMed1984

Identification and quantification of the left-to-right shunt in adults with atrial septal defect by two-dimensional negative contrast echocardiography.

Negative contrast echocardiograms of two-dimensional long axis view of the right ventricle and the atrium were compared with the results of cardiac catheterization and surgical findings in 33 adults with atrial septal defects. Contrast echocardiographic evidence of atrial communication was noted in 30 cases (91%), and, in 28 cases, the negative contrast during one cardiac cycle could be measured. This could be applied even in cases with a small left-to-right shunt or with Eisenmenger's syndrome. No obvious difference in the behavior of negative contrast was documented among the cases with distinct types of septal defects. The maximum negative contrast area and the duration of appearance in one cardiac cycle were related to the pulmonary-to-systemic flow ratio. However, a significant overlap and considerable effects of transducer angulation on measurements were documented. Thus, negative contrast echocardiography may be widely used for the noninvasive identification of a left-to-right shunt in atrial septal defects. However, the method is not appropriate for a precise quantification of three-dimensional shunt flow.

Adolescent↗
PubMed1984

[Apical hypertrophy as a part of the morphologic spectrum of hypertrophic cardiomyopathy].

Clinical and morphological features in 10 cases of "apical hypertrophic cardiomyopathy" (apical type) were analyzed and compared with those in classic hypertrophic cardiomyopathy with asymmetric septal hypertrophy (ASH). The hypertrophic pattern of the interventricular septum (IVS) was evaluated on the two-dimensional echocardiographic (2-D) left ventricular (LV) long-axis view. Thirty-one of 70 patients with ASH were characterized by predominant hypertrophy of the basal IVS (Type I). Seventeen patients had predominant hypertrophy of the apical IVS (Type III). Diffuse IVS hypertrophy was noted in 22 patients (Type II). Electrocardiographic similarity was documented between cases with Type III and apical type; that is, a low incidence of abnormal Q waves, a high incidence of giant negative T waves, and frequent absence of Q waves. In Type I and II, abnormal Q waves were frequently observed, while giant negative T waves were rare. On the 2-D LV short-axis view at the papillary muscle level, three groups with ASH revealed similar distributions of myocardial hypertrophy characterized by extension of hypertrophy to the LV anterior free all and papillary muscles. Most cases with apical type had a similar distribution of hypertrophy, but its degree was significantly less severe than that of ASH. Comparison of diastolic LV configurations on left ventriculograms and/or the 2-D apical two-chamber views indicated the morphologic continuity among the three types with ASH and the apical type. Clinical features in cases of the apical type were obviously less severe than those of three groups with ASH, as indicated by a significantly larger proportion of asymptomatic patients (90%), absence of sudden death and rare documentation of malignant ventricular arrhythmias on 24-hours ambulatory electrocardiography. In conclusion, apical type can be categorized as a part of hypertrophic cardiomyopathy with a wide morphologic spectrum rather than the separate disease entity, and it is characterized by giant negative T waves with minimum clinical manifestations.

Cardiac Catheterization↗
PubMed1983

Secondary ion mass spectra of neutral sphingoglycolipids.

Secondary ion mass spectra of underivatized neutral sphingoglycolipids are presented. In the spectra of mono- and di-glycosylceramide, ions (M + H)+ and (M + H-H2O)+ were observed as relatively intense quasimolecular ions, whereas in the spectra of higher glycolipids, the quasimolecular ion species were predominantly (M + Na)+. Ions due to the ceramide moiety were observed as intense peaks comparable to quasimolecular ions. Ions derived from the fragments cleaved at the glycosidic linkages were hardly detected due to their low intensities. In general, secondary ion mass spectrometry provides good stable spectra for a long time during analysis.

Glycosphingolipids↗
PubMed1983

Comparative study of acidic glycosphingolipids by field desorption and secondary ion mass spectrometry.

Acidic glycosphingolipids were analyzed by field desorption (FD-MS) and secondary ion mass spectrometry (SI-MS) using the primary ion Xe+ with a glycerol matrix. In the analysis of underivatized gangliosides by FD-MS, the fragment corresponding to the asialo residue resulting from the cationized cluster ion (M + Na)+ was the base peak, and ions due to cleavage at the glycosidic linkages were detected, as in the neutral glycosphingolipids. In the case of sulfatide, the ceramide fragment showed the highest intensity in the spectrum. In SI-MS spectra of acidic glycosphingolipids, (M + Na)+, (M + 2Na-H)+, and (M + K)+ were continuously detected as relatively high intensity ions during analysis of gangliosides and sulfatide. Other ions were mostly similar to those obtained by FD-MS. In FD-MS spectra of permethylated gangliosides, the cationized molecular ion (M + Na)+ was the base peak, and fragment ions due to asialo gangliosides were prominent. Other peaks were hard to detect. In SI-MS, molecular ions (M + H)+ and (M + H-32)+ and other ions due to cleavage of the glycosidic linkages were clearly detected. In this case, the sensitivity was greatly improved. Ions due to the non reducing end sugars were clearly detected, because of the relatively low intensity of ion peaks due to the glycerol matrix. It is concluded that the combination with FD-MS and SI-MS is particularly useful for the determination of molecular weight, sugar sequence and ceramide structure with sample amounting to only a few micrograms order.

Animals↗
PubMed1983

Clonal variation for tolerance to polyethylene glycol-induced water stress in cultured tomato cells.

Cell clones were isolated from a population of cultured tomato (Lycopersicon esculentum Mill cv VFNT-cherry) cells and their tolerance to polyethylene glycol (PEG)-induced water stress was measured. Considerable variation for tolerance among the clones was found. Tolerance differences between clones appeared to be spontaneous and were different from tolerance differences between adapted and unadapted cells. Unlike adapted (selected by exposure to PEG) cells, cell clones retained their relative tolerance for many generations in the absence of selection pressure, and tolerance of both relatively tolerant and intolerant clones was very dependent on growth cycle stage and inoculum density. Analysis of subclones isolated from relatively tolerant and intolerant parent clones revealed that each parent clone gives rise to progeny with tolerances near the mean tolerance of both parents. However, progeny populations of both tolerant and intolerant parents are enriched with individuals with phenotypes nearer the mean response of their respective parent populations. When exposed to PEG, relatively tolerant and intolerant clones alike become adapted to the level of PEG to which they are exposed, and have the same phenotypic level of tolerance. Thus, selection by exposure to stress is unable to discriminate (on the basis of growth) between the innately tolerant and intolerant cell types within the population. This is indicated also by the fact that clones isolated from a population of cells adjusted to growth on 25% PEG do not show an enriched frequency of tolerant phenotypes when grown in the absence of PEG compared to the nonselected normal cell population which has never been adjusted to growth on PEG.

Journal Article↗
PubMed1983

Solutes contributing to osmotic adjustment in cultured plant cells adapted to water stress.

Osmotic adjustment was studied in cultured cells of tomato (Lycopersicon esculentum Mill cv VFNT-Cherry) adapted to different levels of external water potential ranging from -4 bar to -28 bar. The intracellular concentrations of reducing sugars, total free amino acids, proline, malate, citrate, quaternary ammonium compounds, K(+), NO(3) (-), Na(+), and Cl(-) increased with decreasing external water potential. At any given level of adaptation, the maximum contribution to osmotic potential was from reducing sugars followed by potassium ions. The sucrose levels in the cells were 3- to 8-fold lower than reducing sugar levels and did not increase beyond those observed in cells adapted to -16 bar water potential. Concentrations of total free amino acids were 4- to 5-fold higher in adapted cells. Soluble protein levels declined in the adapted cell lines, but the total reduced nitrogen was not significantly different after adaptation. Uptake of nitrogen (as NH(4) (+) or NO(3) (-)) from the media was similar for adapted and unadapted cells. Although the level of quaternary ammonium compounds was higher in the nonadapted cells than that of free proline, free proline increased as much as 500-fold compared to only a 2- to 3-fold increase observed for quaternary ammonium compounds. Although osmotic adjustment after adaptation was substantial (up to -36 bar), fresh weight (volume increase) was restricted by as much as 50% in the adapted cells. Altered metabolite partitioning was evidenced by an increase in the soluble sugars and soluble nitrogen in adapted cells which occurred at the expense of incorporation of sugar into cell walls and nitrogen into protein. Data indicate that the relative importance of a given solute to osmotic adjustment may change depending on the level of adaptation.

Journal Article↗