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Biomedical subjects

S Imai

Publications and source records attributed to S Imai.

At least 433 records · Page 24Linked to original sources
PubMed1990

Neonatal alloimmune thrombocytopenic purpura associated with sensitization against the platelet-specific antigen Yuk(a).

We report a Japanese newborn who developed alloimmune thrombocytopenia by the antibodies to the newly discovered platelet antigen Yuk(a). The infant recovered uneventfully in 10 days without specific treatment. Antiplatelet alloantibodies in the patient were IgG class detected by mixed passive hemagglutination (MPHA). Family study showed that Yuk(a) antigen was inherited as an autosomal dominant trait. Cases with Yuk(a)-associated alloimmune thrombocytopenia are reviewed.

Antigens, Human Platelet↗
PubMed1990

Orally administered streptococcal preparation, OK-432 augments the antitumor immunity of patients with gastric or colorectal cancer.

A streptococcal preparation, OK-432, was orally administered at a dose of 5 KE to patients with gastric or colorectal cancer for 7-14 days before their operations, and its immunomodulatory effects on peripheral blood lymphocytes (PBL), regional node lymphocytes (RNL) and tumor infiltrating lymphocytes (TIL) were assessed. The group treated with OK-432 included 8 gastric and 6 colorectal cancer patients, and the control group included 8 gastric and 8 colorectal cancer patients. The NK cell activity of PBL was significantly augmented by the oral administration of OK-432, and the proportions of Leu 7+ and Leu 11+ cells in PBL also increased. The responses of PBL and TIL to autologous tumor extracts in the presence of interleukin-2 were enhanced after the oral administration of OK-432. The proportion of OKT8+ cells in PBL increased after treatment with oral OK-432, whereas the proportion in RNL significantly decreased. These results indicate that oral OK-432 affects NK and T cells and may augment the antitumor immunity of patients with gastrointestinal cancer.

Administration, Oral↗
PubMed1990

DNA rearrangements of the int region in spontaneous mouse mammary tumors of SHN/S and SLN/S mice.

SHN and SLN mice originating from the same Swiss albino stock are genetically very close to each other. The incidence and latent period of mammary tumor development in SHN mice were higher and shorter than those in SLN. To elucidate these differences in the behavior of mammary tumorigenesis, the frequency of insertion of mammary tumor viral genes within the int-1 and int-2 regions in spontaneous mammary tumors from their two substrains, SHN/S and SLN/S, were compared. The frequency of provirus integration into either int-1 or int-2 in DNAs from mammary tumors was 52% (11/21) in SHN/S and 45% (5/11) in SLN/S. The frequency of insertion within int-1 or int-2 could not account for the different susceptibilities of SHN/S and SLN/S.

Animals↗
PubMed1990

Effect of amnionitis on the complement system of preterm infants.

The development of the complement system was studied by quantitation of total hemolytic complement activity (CH50), C1q, C3, C4, and C3 split product (C3d) in cord plasma of nine human fetuses (17-22 weeks of gestation), 110 preterm (24-36 weeks of gestation) and 30 term neonates. The complement levels were analyzed in relation to various illnesses of preterm infants. Histological examination of the placenta revealed a higher incidence of amnionitis in the placenta of less than 34 gestational weeks. In cases without amnionitis, there were significant correlations between complement levels and gestational age. In cases with amnionitis, the complement system was activated even in infants of less than 28 weeks gestation. The complement levels correlated with the extent of the inflammation in the placentas and umbilical cords except for C1q. In infants with Wilson-Mikity syndrome, complement levels other than C1q were significantly elevated in comparison with those of infants with respiratory distress syndrome. In the group of preterm infants without amnionitis, no differences were found between infants with intrauterine growth retardation and those with growth appropriate for gestational age.

Chorioamnionitis↗
PubMed1990

Morphological study of normal and tumor cells in the head and neck region using irradiated collagen gel embedding technique: morphological study using collagen gel.

Fourteen specimens of normal, benign, or malignant tumor cells from the head and neck region were subjected for culture using 0.2% of irradiated collagen gel embedding technique. Re-differentiation of glands within the gel in serum-free medium was observed. There were marked differences in the growth patterns within the gel between normal or benign and malignant cells. Four normal glands and 5 out of 6 benign tumors showed branch-like growth patterns. On the other hand, malignant tumors showed no branch-like pattern, or could not grow at all. The results showed that the collagen gel technique could be useful for the differential diagnosis of malignancy in head and neck tumors.

Cell Differentiation↗
PubMed1990

Functional effects of intraoral reconstruction with a free radial forearm flap.

Postoperative articulation was investigated in patients who underwent glossectomy and reconstruction with free radial forearm flaps. The methods of evaluation consisted of scores for intelligibility of 100 Japanese syllables and 3 groups of glossal sounds. The glossal sounds, based on palato-lingual contact (lingogram), were useful to evaluate function of the respective parts of the tongue. One patient who had had a partial glossectomy and resection of the floor of the mouth achieved an overall score of 80.5% one year postsurgery, and his glossal sounds were also excellent. Three patients who underwent removal of the floor of the mouth and hemiglossectomy, excluding the root of the tongue, had overall scores ranging from 45.6% to 82.1%. Two of these had particularly low scores for the glossal sounds produced with the rear part of the tongue, and this suggested the necessity for suspension slings to prevent depression of the reconstructed tongue and the floor of the mouth. The hemiglossectomy with partial mandibulectomy had an acceptable score of 68.7%. Chronologically, the glossal sounds produced with the rear part and the blade of the tongue often tended to improve postsurgery.

Aged↗
PubMed1990

High resolution ultrasound of the chest wall.

To study the detailed normal ultrasonic anatomy of the pleura and chest wall, high resolution (7.5 MHz) ultrasonograms were obtained from cadaver chest wall specimens and compared with thin section computed tomograms and anatomical specimens. Ultrasonograms show three layers of the intercostal muscles (internal, external and innermost), covered by the "echogenic pleural line." The "echogenic pleural line" is caused by composite echoes from the inner parietal pleura, and the outer endothoracic fascia, with the fatty tissue covering both sides of the fascia, which are located deep to the chest wall muscles. On ultrasonograms, the subpleural fat tissue, when abundant, appeared as an apron-like structure hanging down from the inner surface of the rib (subpleural fat pad), or diffuse fat accumulation mimicking the pleural thickening.

Humans↗
PubMed1990

Two high affinity (Ca2+ + Mg2+)-ATPases of vascular smooth muscle plasma membrane preparation. Their relation to the Ca2(+)-pumping ATPase.

High affinity Ca2(+)-activated, Mg2(+)-dependent ATP-ase [Ca2+ + Mg2+)-ATPase) activities were characterized in the membrane fractions of the porcine aorta. The (Ca2+ + Mg2+)-ATPase activity, similar to those found in the plasma membranes of the erythrocyte and the heart, ie, Ca2(+)-pumping ATPase activity, was not found in the membrane fractions isolated by the conventional method. The activity, however, became apparent in a plasma membrane-enriched fraction obtained from the microsomes treated with digitonin. The enzyme activity was stimulated by a purified C-kinase and by cyclic GMP or a purified cyclic GMP-dependent protein kinase (G-kinase). In addition to the Ca2(+)-pumping ATPase which requires millimolar concentration of Mg2+ for its activity, another high affinity (Ca2+ + Mg2+)-ATPase was detected that required micromolar concentration of Mg2+ for its full activation. Cell fractionation studies suggested its localization to plasma membranes, but the biochemical characteristics of the enzyme indicated that the enzyme could not be a biochemical expression of the plasma membrane Ca2+ pump.

Animals↗
PubMed1990

On the mode of cardioprotection produced by a new bradycardic agent, FR 76830, during ischaemia and after reperfusion in the isolated perfused rat heart: a 31P-NMR study.

STUDY OBJECTIVE: The aim was to investigate the effects of a newly synthesised bradycardiac agent, FR 76830, on cardiac mechanical function and metabolism during ischaemia and reperfusion. DESIGN: FR 76830 and diltiazem were infused during 15 min before ischaemia. Hearts were then subjected to ischaemia (40 min) followed by reperfusion (40 min). High energy phosphate compounds and myocardial pH were assessed by 31P-NMR. The effects of bradycardia induced by FR 76830 before induction of ischaemia on the metabolic derangement resulting from ischaemia and on functional and metabolic recovery after reperfusion were examined in comparison with diltiazem. EXPERIMENTAL MATERIAL: Male Wistar rats (about 250 g) were used. MEASUREMENTS AND MAIN RESULTS: FR 76830 and diltiazem produced a dose dependent decrease in heart rate before ischaemia. However, the decrease in the double product (heart rate x left ventricular pressure) was observed only with diltiazem. Both FR 76830 and diltiazem attenuated the fall in myocardial pH during early ischaemia and improved the level of ATP during late ischaemia. Diltiazem also produced an improvement in myocardial acidosis during late ischaemia and in the level of ATP during early ischaemia. CONCLUSIONS: The importance of bradycardia in protection of the myocardial cells during early ischaemia and in preservation of ATP content during late ischaemia and after reperfusion was shown. However, to produce an improvement in myocardial pH during late ischaemia a decrease in the double product is needed.

Adenosine Triphosphate↗
PubMed1990

Sarcolemmal (Ca2(+)+Mg2+)-ATPase of vascular smooth muscle and the effects of protein kinases thereupon.

To elucidate the regulation mechanisms for sarcolemmal Ca2(+)-pumping ATPase of vascular smooth muscle, the preparation of the membrane fraction of porcine aorta with which the enzyme activity could be analyzed was attempted. A Ca2(+)-activated, Mg2(+)-dependent ATPase [Ca2(+)+Mg2+)-ATPase) activity with high affinity for Ca2+ (Km = 79 +/- 18 nM) was found in a sarcolemma-enriched fraction obtained from digitonin-treated microsomes that possessed the essential properties of plasma membrane (PM) Ca2(+)-pumping ATPases, as determined for the erythrocyte and cardiac muscle enzymes. The activity was stimulated by calmodulin and inhibited by low concentrations of vanadate. Saponin had a stimulatory effect on it. The existence of the PM enzyme in the membrane fraction was substantiated by the Ca2(+)-dependent, hydroxylamine sensitive phosphorylation of a 130K protein, which could be selectively enhanced by LaCl3. The enzyme activity was potentiated by either cGMP or a purified G-kinase. Purified protein kinase C potentiated the enzyme activity. However, none of these agents stimulated the activity of the enzyme purified from microsomes by calmodulin affinity chromatography. The results suggest that the sarcolemmal Ca2(+)-pumping ATPase of vascular smooth muscle is regulated by these protein kinases not through phosphorylation of the enzyme itself but through phosphorylation of membrane components(s) other than the enzyme. Phosphatidylinositol phosphate was found to stimulate the enzyme, suggesting its role in mediation of the stimulatory effects of the protein kinases.

Animals↗
PubMed1990

A Ca2(+)-activated, Mg2(+)-dependent ATPase with high affinities for both Ca2+ and Mg2+ in vascular smooth muscle microsomes: comparison with plasma membrane Ca2(+)-pump ATPase.

A Ca2(+)-ATPase with a high affinity for free Ca2+ (apparent Km of 0.13 microM) was found and characterized in membrane fractions from porcine aortic and coronary artery smooth muscles in comparison with the plasma membrane Ca2(+)-pump ATPase purified from porcine aorta by calmodulin affinity chromatography. The activity of the high-affinity Ca2(+)-ATPase became enriched in a plasma membrane-enriched fraction, suggesting its localization in the plasma membrane. The enzyme was fully active in the absence of exogenously added Mg2+, but required a minute amount of Mg2+ for its activity as evidenced by the findings that it was fully active in the presence of 0.1 microM free Mg2+ but lost the activity in a reaction mixture containing trans-cyclohexane-1,2-diamine-N,N,N',N'-tetraacetic acid as a divalent cation chelator which has, unlike EGTA, high affinities for both Ca2+ and Mg2+. It was able to utilize a variety of nucleoside di- and triphosphates as substrates, such as ADP, GDP, ATP, GTP, CTP, and UTP, showing a broad substrate specificity. The activity of the enzyme was not modified by calmodulin (5, 10 micrograms/ml). Trifluoperazine, a calmodulin antagonist, had a partial inhibitory effect on the activity at 30 to 240 microM, but this inhibition could not be reproduced by a more specific calmodulin antagonist, W-7, indicating that this inhibition by trifluoperazine was not specific. Furthermore, the high-affinity Ca2(+)-ATPase activity was not modified either by low concentrations (0.5-9 microM) of vanadate or by 1-100 microM p-chloromercuribenzoic acid. Cyclic GMP, nitroglycerin, and nicorandil did not have any effect on the enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Effect of epidermal growth factor in combination with sucralfate or omeprazole on the healing of chronic gastric ulcers in the rat.

Epidermal growth factor (EGF) has been shown to enhance healing of experimental gastric ulcers when given subcutaneously or orally in the drinking water. This effect of EGF occurs without reducing gastric acid secretion. On the other hand, EGF reportedly is excreted rapidly from gastric lumen when administered by intragastric bolus. This suggests that further stimulation of ulcer healing may be expected if EGF is given with an acid-suppressive agent or with an agent allowing EGF to remain in rat gastric lumen at high concentrations. In the present study, EGF administered by gastric intubation at a dose of 10 micrograms/kg, which is three times smaller than reported in previous studies, was evaluated for its effect on acetic acid-induced rat gastric ulcers in combination with sucralfate or omeprazole. Sucralfate is well known selectively to bind proteins covering the ulcer base, and omeprazole is a potent acid-suppressive agent. Prior to the study of combined EGF and sucralfate, oral sucralfate was confirmed to allow endogenous gastric EGF and mouse EGF given exogenously to remain at high concentrations in gastric contents and tissues. EGF and sucralfate (2 g/kg/day) given alone failed to stimulate ulcer healing in submandibularectomized rats (SMR rat) whose endogenous gastric EGF was depleted. However, the combination of both drugs administered at the same doses significantly accelerated ulcer healing in the SMR rat. Omeprazole (200 mg/kg/day) significantly enhanced ulcer healing regardless of removal of the submandibular glands. The combination of EGF and omeprazole further stimulated ulcer healing in the SMR rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1990

Adrenoceptor-blocking activity and cardiohemodynamic effects of carvedilol in animals.

The beta-blocking activities of a new beta-adrenoceptor blocking drug, carvedilol, evaluated in isolated atria and trachea of the guinea pig were 2.0 (beta 1) and 3.2 times (beta 2), respectively, as potent as those of propranolol. Carvedilol exhibited the alpha-blocking activities in the aorta of guinea pigs and rats. Carvedilol was 2 and 50 times less potent in guinea pigs and rats, respectively, than prazosin as an alpha-blocker. Thus, the alpha-blocking activities were twice as potent as the beta-blocking activity in the rat and one-fifth that of the beta-blocking activity in the guinea pig. In anesthetized open-chest dogs, the beta-blocking activity of carvedilol was 1.5 times more potent than that of propranolol and had 3.8 times the alpha-blocking activity. Thus, carvedilol is a nonselective beta-blocking drug with a potent alpha-blocking activity. Carvedilol and propranolol showed dose-dependent and significant decreases in the blood pressure, total cardiac output, left ventricular pressure, dp/dt, heart rate, coronary flow, and oxygen consumption in anesthetized open-chest dogs. Carvedilol decreased the total peripheral resistance significantly (the decrease was not proportional to the decreases in the blood pressure at high doses), while propranolol increased it significantly and dose-dependently. These results indicate the importance of alpha-adrenoceptor blocking activity in the decrease in blood pressure produced by carvedilol.

Adrenergic alpha-Antagonists↗
PubMed1990

Carboxyphosphonoenolpyruvate phosphonomutase, a novel enzyme catalyzing C-P bond formation.

An enzyme catalyzing the formation of an unusual C-P bond that is involved in the biosynthesis of the antibiotic bialaphos (BA) was isolated from the cell extract of a mutant (NP71) of Streptomyces hygroscopicus SF1293. This enzyme, carboxyphosphonoenolpyruvate (CPEP) phosphonomutase, was first identified as a protein lacking in a mutant (NP213) defective in one of the steps in the pathway to BA. The first 30 residues of the amino terminus of this protein were identical to those predicted by the nucleotide sequence of the gene that restored BA production to NP213. The substrate of the enzyme, a P-carboxylated derivative of phosphoenolpyruvate named CPEP, was also isolated from the broth filtrate of NP213 as a new biosynthetic intermediate of BA. CPEP phosphonomutase catalyzes the rearrangement of the carboxyphosphono group of CPEP to form the C-P bond of phosphinopyruvate.

Anti-Bacterial Agents↗
PubMed1990

Establishment and characterization of a human ovarian serous cystadenocarcinoma cell line that produces the tumor markers CA-125 and tissue polypeptide antigen.

A cultured cell line (SHIN-3) derived from a human ovarian serous cystadenocarcinoma which consistently produces two tumor markers, CA-125 and tissue polypeptide antigen (TPA) was established. After 1 week of culture of 1 x 10(5) cells, high levels of tumor marker were observed (the total CA-125 release was 1,500 U and the total TPA release was 37.5 U). Expression of CA-125 and TPA was also demonstrated in cultured cells immunohistochemically. The volume of CA-125 release per cell was highest just before the start of the logarithmic growth phase. TPA production was increased in the logarithmic growth phase, but its relationship to the total number of cells was not clear.

Animals↗
PubMed1990

Studies on the synthesis of compounds related to adenosine-3',5'-cyclic phosphate. VI. Synthesis and cardiac effects of N6,N6,2'-O-trialkyl-, N6,2'-O-dialkyl-, and 2'-O-alkyladenosine-3',5'-cyclic phosphates.

The alkylation of adenosine-3',5'-cyclic phosphate (cAMP, 1) with alkyl bromides was investigated and various new alkylated cAMP derivatives, N6,N6,2'-O-trialkyl cAMPs (2), N6,2'-O-dialkyl cAMPs (3) and 2'-O-alkyl cAMPs (4), were prepared by a one step reaction without the introduction of a protecting group into 1. Compounds (2) were synthesized from 1 by treatment with alkyl bromides in the presence of NaH or potassium tert-butoxide in dimethyl sulfoxide. Compounds (3) were also synthesized from 1 under conditions similar to those of the synthesis of 2 except for the use of MeONa as a base. Compounds (4) were prepared from 1 by treatment with alkyl bromides in the presence of 18-crown-6 in dioxane-aqueous KOH solution. N6,2'-O-Dibenzyl cAMP (3e) was obtained from 1 by the same method as the preparation of 4. These new alkylated derivatives were evaluated for cardiotonic activity in vitro. Some of them showed weak positive inotropic effects and strong negative chronotropic effects. Thus, the presence of the 2'-hydroxyl group seemed to be essential for the appearance of potent positive inotropic activity caused by cAMP derivatives.

Animals↗
PubMed1990

Studies on the synthesis of compounds related to adenosine 3',5'-cyclic phosphate. VII. Synthesis and cardiac effects of N6,N6-dialkyl adenosine 3',5'-cyclic phosphates.

A series of novel N6,N6-dialkyl adenosine 3',5'-cyclic phosphates N6,N6-dialkyl cAMPs) was synthesized from 2'-O-p-toluenesulfonyl cAMP (2'-O-tosyl cAMP, 2) and tested for inotropic and chronotropic activities in vitro. Treatment of 2 with excess alkyl halides and sodium hydride followed by detosylation with aqueous NaOH readily gave N6,N6-dialkyl cAMPs (3) in good yields. Various N6,N6-dialkyl cAMPs having different alkyl groups at the N6-position (9-12) were prepared by alkylation followed by detosylation of N6-alkyl-2'-O-tosyl cAMPs (4) which were obtained by the reductive alkylation of 2 with aldehydes in the presence of sodium cyanoborohydride in acetic acid or tosylation of N6-methyl cAMP. The mechanism of the detosylation is briefly discussed. Among the N6,N6-dialkylated derivatives, N6,N6-dipentyl (3f) and N6-ethyl-N6-heptyl (10e) derivatives were found to exhibit a potent positive inotropic effect and a weak positive chronotropic effect. The structure-activity relationships for the position and the length of alkyl residue are discussed.

Alkylation↗