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Biomedical subjects

H Harada

Publications and source records attributed to H Harada.

At least 667 records · Page 37Linked to original sources
PubMed1982

Effect of Staphylococcus aureus Cowan i bacteria on the mitogenic response of human B-cell subsets.

We have made a detailed investigation to determine which of the B-cell subsets could be stimulated by Staphylococcus aureus Cowan I bacterium (SpA CoI). B-cell subsets were separated from peripheral blood and tonsil lymphocytes by means of rosette formation with E, EAIgG, anti-immunoglobulin (Ig) conjugated OE (OE-Pro A) or by separation on a bovine serum albumin (BSA) discontinuous density gradient. The cells responding to SpA CoI included E receptor negative (E-), C3 receptor positive (C3R+), and surface Ig positive (SIg+) B-cell subsets. Among these B-cell subsets, FcR-n cells were more responsive than FcR+ cells. These B-cell subsets responded alone to SpA CoI and significantly proliferated, although, they failed to respond alone to pokeweed mitogen (PWM) and Protein A of S. aureus (Protein A). Among the SIg+ B-cell subsets stimulated with SpA CoI, IgM+ and IgG+ B cells showed much less response. Both Protein A receptor positive (Pro A . R+) and negative (Pro A . R-) cells responded well to SpA CoI. Fractionation of B cells on a BSA gradient revealed that comparatively small sized and denser B-cell subsets responded well to SpA CoI. From these criteria, it is suggested that B cells responding to SpA CoI are capable of stimulating not only mature B cells, but can also stimulate immature B cells.

B-Lymphocytes↗
PubMed1981

Trapidil stimulation of slow Ca2+ current in cardiac muscle.

The effect of trapidil, a coronary vasodilator and positive inotropic agent (associated with elevated tissue cyclic AMP levels due to phosphodiesterase inhibition), was examined on the electrophysiological properties of cardiac muscle. Specifically, the trapidil was tested for its ability to induce slow action potentials (APs), and to affect the maximum upstroke velocity (+Vmax) of the slow APs in the ventricular myocardial cells of isolated perfused chick hearts. The effect of trapidil on the contractions accompanying the slow APs and on the tissue cyclic AMP levels was also examined. To study the slow channels exclusively, the fast Na+ channels were voltage-inactivated by elevated (25 mM) K+. In this condition of functional removal of the fast channels, the hearts could not be excited even by intense electrical stimulation. It was found that trapidil (10(-4)--10(-3) M) induced slow APs accompanied by contractions. Elevation of the trapidil concentration produced dose-dependent increases in +Vmax, dT/dt (first derivative of developed tension) and cyclic AMP. These effects of trapidil were not affected by propranolol, suggesting that they were not mediated by beta-adrenergic receptors. These results support the hypothesis that intracellular cyclic AMP levels regulate the number of available slow channels, thereby controlling contractile force in the heart muscle via the Ca2+ influx mediated by slow channels.

Action Potentials↗
PubMed1981

Histochemical studies on protein plugs obtained by endoscopic retrograde catheterization of the papilla.

In order to elucidate mechanisms of protein plug formation, histochemical studies were performed on aggregates and protein plugs present in pancreatic juice. Pancreatic juice was obtained from three control subjects and five patients with chronic pancreatitis through endoscopic retrograde catheterization of the papilla. Specimens for staining were prepared in two ways: (1) fixed with 10 per cent formaldehyde, embedded in paraffin and sectioned, and (2) placed on slide glass and fixed with isopropylalcohol. Staining included hematoxylin-eosin, periodic-acid Schiff, von Kossa, alcian blue, toluidine blue and double staining with PAS and AB. The process of protein plug formation can be as follows: (1) a prerequisite for aggregate formation, consisting of clusters of desquamated epithelial cells, highly concentrated sulfated acidic mucopolysaccharide and neutral mucopolysaccharide, (2) formation of aggregates in which epithelial cells and amorphous substance are interlaced with developing fine reticular substance, (3) enlargement of aggregates by fusion with adjacent aggregates through bridging action of the reticular substance sprouting, like prickles, from their surface, and (4) "maturity" of aggregates, taking a three-dimensional form which result in a spherical, spheroidal or cylindrical protein plug.

Amylases↗
PubMed1981

Comparative studies on viscosity and concentration of protein and hexosamine in pure pancreatic juice.

In order to investigate the cause of an increase in viscosity of pancreatic juice in patients with chronic pancreatitis, we performed comparative studies on voscosity and concentration of protein, hexosamine, three hydrolytic enzymes (amylase, chymotrypsinogen and lipase), calcium and gamma-Glutamyltranspeptidase in pure pancreatic juice. Pure pancreatic juice (PPJ) was obtained from seven control subjects, 10 patients with probable chronic pancreatitis and six patients with definite chronic pancreatitis by means of endoscopic retrograde catheterization of the papilla. Specimens were collected in ice-cooled tubes during the initial four-minute period and thereafter at two-minute intervals for 20 minutes after a rapid intravenous injection of secretin (Eisai Secrepan, 1 U/kg of body weight) and then at one-minute intervals for 10 minutes after a rapid intravenous injection of pancreozymin (Boots, 1 U/kg of body weight). It was demonstrated that the viscosity of PPJ was closely related to the concentration of hydrolytic enzyme protein, hexosamine and the presence of mucous substance and protein plugs.

Amylases↗
PubMed1981

A simple and rapid latex fixation test for measuring immunoglobulins produced in cell cultures.

A rapid and simple latex fixation test (LFT), which quantifies immunoglobulin (Ig) released into culture supernatants is described. Latex particles are coated with rabbit anti-human IgG, IgA or IgM antibodies. With this LFT technique the concentration of Ig is determined within a few minutes. The LFT is as sensitive and quantitative as double-antibody radioimmunoassay and is capable of detecting 35, 68 and 225 ng/ml of IgG, IgA and IgM, respectively.

Animals↗
PubMed1981

Transfer of Liposome-Sequestering Plasmid DNA into Daucus carota Protoplasts.

Reverse-phase evaporation lipid vesicles (REV) liposomes, consisting of phosphatidyl choline and stearylamine in 1:3 molar ratio, encapsulated approximately 30% of exogenously supplied recombinant DNA vector, pBR322. The DNA sequestered in REV liposomes was highly tolerant to DNase.A two-step procedure was developed, which involves encapsulation of DNA with liposomes using one-tenth phosphate-buffered saline-0.5 molar mannitol, followed by incubation of liposome-DNA with protoplasts in phosphate buffer-0.5 molar mannitol.About 11% of liposome-encapsulated DNA was transferred into protoplasts, whereas 6% uptake was observed in the control. Although some degradation of incorporated DNA occurred inside protoplasts, 50% of the total radioactivity resolved by 0.8% agarose gel was associated with pBR322 forms in 5-hour incubation. After 20-hour incubation, open circular DNA disappeared completely and maintenance of covalently closed circular DNA was confirmed.

Journal Article↗
PubMed1981

Stimulation of Immunoglobulin production from human B lymphocytes by Staphylococcus aureus: effects of monocytes and con A-induced suppressor cells.

Significant immunoglobulin (Ig) production by human peripheral blood lymphocytes was induced in vitro by stimulating the cells with pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (SpA CoI). IgG, IgM, and IgA were determined by a combination of the latex fixation test and radioimmunoassay. High levels (1,000 to 5,000 microgram/ml of IgG and IgM and a lesser amount of IgA were constantly produced during 7 to 8 days of incubation with both stimulants. Ig production induced by SpA CoI stimulation was independent of the presence of T cells, while Ig production induced by PWM required T cells exclusively. Depletion of monocytes in the culture caused but a slight decrease in Ig production (particularly in the case of IgG). While the addition of a small number of monocytes enhanced IgG induction by both stimulants, coculture with an excess number of monocytes inhibited Ig induction (particularly IgG) by PWM stimulation but not by SpA CoI stimulation. Marked suppression of Ig production (IgG, IgM, and IgA) was observed in cocultures with Con A-activated T cells. The phenomena of suppression were observed in both the SpA CoI-stimulated and PWM-stimulated lymphocytes. These data indicated that Ig production from B cells and relatively of independent of monocytes, but could be subjected to the regulation of the Con A-induced suppressor T cells.

Antibody Formation↗
PubMed1981

Hemoglobin Yusa (beta 21 (B3) Asp leads to Tyr), a new abnormal hemoglobin found in Japan.

An electrophoretically slowly moving hemoglobin variant, Hb Yusa, was found in a 48-year-old man, his younger sister and mother. No clinical or hematological abnormalities were seen in the individuals heterozygous for this mutant gene. Structural studies of this abnormal hemoglobin showed a new type substitution of beta 21 (B3) Asp leads to Tyr. The percentage of the abnormal hemoglobin in the hemolysate was 40.8. The hemoglobin had neither instability nor functional abnormality.

Amino Acids↗