Biomedical subjects

Y Imai

Publications and source records attributed to Y Imai.

At least 901 records · Page 50Linked to original sources

PubMed1990

Terminal differentiation to mature neutrophils and eosinophils in suspension culture of the blast progenitors in acute myeloblastic leukemia.

The blasts obtained from three freshly diagnosed acute myeloblastic leukemia (AML) patients were cultured in suspension to determine whether leukemic blast progenitors can indeed differentiate to form mature granulocytes. One patient was AML M2. The other two patients were bilineal and biphenotypic leukemia, respectively. Media conditioned by human bladder carcinoma line 5637 (5637-CM) or recombinant human granulocyte colony-stimulating factor (rhG-CSF) was added to stimulate growth. In suspension, clonogenic cells grew for 1-3 weeks in two patients, while they did not increase in one patient. After repeated subculture, cells of blast morphology decreased in percentage and polymorphonuclear neutrophils, eosinophils, and monocyte-macrophages appeared. Lymphoid cell component of the patient 2, who was diagnosed as bilineal leukemia by dual-color immunofluorescence analysis, decreased in number after suspension culture and cells of myeloid phenotype became dominant. The findings show that clonogenic blast progenitors can renew themselves and can also undergo terminal differentiation to mature end cells.

Adult↗

PubMed1990

[The indication and effects of palliative right ventricular outflow tract reconstruction for tetralogy of Fallot with pulmonary atresia].

Palliative right ventricular outflow reconstruction (RVOT) in 5 cases with tetralogy of Fallot with valvular pulmonary atresia and 5 cases with truncal pulmonary atresia were studied regarding indication and postoperative development of pulmonary artery. In 4 cases with valvular atresia, RVOT was performed following previous palliation such as Blalock-Taussig shunt, and resulted in improvement in clinical symptoms and in significant increase in postoperative PA-index from 105.4 mm2/m2 before operation to 159.4 mm2/m2. In one case, RVOT was performed as the first stage palliation and symmetrical development of pulmonary arteries were observed. All underwent successful total correction later. However, in 5 cases with the truncal atresia, 2 died after RVOT and postoperative development of pulmonary artery was insignificant. RVOT is indicated for cases with poor pulmonary arterial development despite of palliation, and in future, RVOT as an initial palliation will be indicated in infants with hypoplastic pulmonary artery.

Child↗

PubMed1990

[Effects of 7 drugs on cutaneous blood flow evoked by electric stimulation of rat sciatic nerve].

The non-invasive technique of laser-Doppler flowmeter (LDF) was used to measure the change of cutaneous blood flow evoked by electric stimulation of rat sciatic nerve. The sciatic nerve was cut centrally and placed on bipolar electrodes. Drug were infused in a carotid artery. Electric stimulation of the sciatic nerve containing sensory afferent fibers caused an increase in cutaneous blood flow. This increase was not modified by the ia infusion of adrenergic blocking agents (phentolamine, 0.1 mg/kg and propranolol, 0.5 mg/kg), anti-muscarinic agent (atropine 0.5 mg/kg), anti-histamines (mepyramine, 10 mg/kg and cimetidine, 10 mg/kg) and 5-HT antagonist (methysergide, 0.5 mg/kg). Pretreatment with capsaicin (50 mg/kg, sc) in the newborn rat or the ia infusion of spantide (1, 2 mumol/kg) significantly inhibited the the stimulation-induced increase of the blood flow. These results suggest that substance P released from the peripheral endings of sensory nerve may be involved in vasodilation following electric stimulation of the sciatic nerve in rat.

Analgesics↗

PubMed1990

[A pharmacological study of the participation of the peripheral endings of primary afferent neurons in the inflammatory response evoked by heat and mechanical noxious stimulation].

To investigate the participation of neuropeptides present in the peripheral endings of primary afferent neurons in the inflammatory response, immunoreactive substance P (iSP), calcitonin gene-related peptide (iCGRP) and neurokinin A (iNKA) levels in the s.c. perfusate, and inflammatory response (edema and plasma protein extravasation) evoked in rat paw by noxious stimulation were determined. The effects of these peptides on plasma protein extravasation in the skin of the hind paw of mice were also examined with the pontamine sky blue protein labelling method. The following results were obtained. 1) Immersion of the rat hind paw for 30 min into hot water adjusted to 47 degrees C led to a marked increase in the release of iSP and iCGRP in the subcutaneous perfusate with the formation of thermal edema. 2) Mechanical stimulation (600 g, 10 min) to the hind paw or electrical stimulation of the saphenous and sciatic nerves (10 V, 2 Hz, 1msec duration, 10 min) evoked the increase of iSP release in the perfusate with plasma protein extravasation. 3) iNKA release was not affected by neither heat nor mechanical stimulation. 4) Intraplantar injection of SP, CGRP and NKA induced plasma protein extravasation, the order of potencies being SP greater than CGRP greater than NKA. The action of SP was antagonized by spantide, an SP antagonist. The injection of CGRP with SP produced a synergistic action on plasma protein extravasation. 5) Neonatal pretreatment with capsaicin, which is known to degenerate small-diameter primary afferent neurons, caused the decrease in amount of iSP and iCGRP released during noxious heat stimulation. 6) Pretreatment with Compound 48/80, or stem bromelain and emorphazone, or des-Arg9-[Leu8]-BK, inhibited the iSP release evoked by noxious heat stimulation. 7) Opioids such as morphine (mu-agonist) and ethylketocyclazocine (kappa agonist) inhibited the heat stimulus-evoked iSP release and thermal edema, and the inhibitory effects were antagonized by pretreatment with their antagonists. 8) Morphine or ethylketocyclazocine or [D-Ala2,D-Leu5]-enkephalin (delta-agonist) inhibited the release of iSP evoked by electrical stimulation of the saphenous and sciatic nerves. These results indicate that SP and CGRP present in peripheral endings of small-diameter primary afferent neurons play an important role in the inflammatory response, and that opioids are involved in the regulation of inflammatory response through the inhibition of SP release.

Animals↗

PubMed1990

Does ambulatory blood pressure monitoring improve the diagnosis of secondary hypertension?

Ambulatory blood pressure monitoring can determine the average blood pressure level and the short- and long-term blood pressure variability (circadian rhythm). The circadian blood pressure rhythm appears to be mediated mainly by the circadian rhythm of the sympathetic tone which is linked to changes in physical and mental activity, e.g. the waking-sleeping cycle. A statistically significant circadian blood pressure rhythm was observed in approximately 80% of mild to moderate essential hypertensive patients as well as in normal subjects. However, in patients with Cushing's syndrome, under glucocorticoid treatment, or with hyperthyroidism, central and/or peripheral autonomic dysfunction (Shy-Drager syndrome, spinal cord injury, brainstem lesions, diabetic neuropathy, uremic neuropathy, etc), chronic renal failure, eclampsia, malignant hypertension, sleep apnea syndrome or systemic atherosclerosis, the normal circadian blood pressure rhythm appears to be eliminated or reversed, while in those with primary aldosteronism, renovascular hypertension, pheochromocytoma without paroxysmal hypertension, diabetes insipidus, acromegaly, hyperparathyroidism or hyperprolactinemia, the nocturnal blood pressure fall has been observed as in normal subjects. The alteration in the circadian blood pressure rhythm was observed with different pathophysiological conditions, although no specific pattern was observed for any condition. A disturbance in any part of the hierarchy of factors that regulate the circadian rhythm of sympathetic neural tone seems to disturb the circadian blood pressure rhythm. We conclude that ambulatory blood pressure monitoring is not critically important in the diagnosis of secondary hypertension although it does help in screening for secondary hypertension.

Autonomic Nervous System Diseases↗

PubMed1990

Circadian blood pressure variations under different pathophysiological conditions.

The daily variation in blood pressure (circadian blood pressure rhythm) is characterized by a nocturnal fall and a diurnal rise. The circadian blood pressure rhythm seems to be mediated mainly by the circadian rhythm of sympathetic tone, linked to changes in physical and mental activities, e.g. the waking-sleeping cycle. Statistically significant circadian blood pressure rhythms have been confirmed in approximately 80% of mild to moderate essential hypertensive patients as well as in normal subjects. However, the normal pattern of circadian blood pressure rhythm is reversed in elderly people and in those with Cushing's syndrome, those undergoing glucocorticoid treatment, and those with hyperthyroidism, central and/or peripheral autonomic dysfunction (Shy-Drager syndrome, tetraplegia, diabetic or uremic neuropathy, etc), chronic renal failure, renal or cardiac transplantation, congestive heart failure, eclampsia, sleep apnea syndrome, malignant hypertension, systemic atherosclerosis and accelerated hypertensive organ damage. However, in those with primary aldosteronism, renovascular hypertension, pheochromocytoma without paroxysmal hypertension, or those with cardiac pacing, a nocturnal blood pressure fall is ordinarily observed. It may be that a fall in cardiac output rather than in peripheral resistance may be mainly responsible for the nocturnal fall in blood pressure. It also seems that a nocturnal heart rate fall is not responsible for it, since the nocturnal blood pressure fall remained unchanged in patients undergoing cardiac pacing and was disturbed in patients with Cushing's syndrome or hyperthyroidism in whom the circadian heart rate rhythm remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic Nervous System Diseases↗

PubMed1990

Tumor necrosis factor alpha and interferon gamma inhibit proliferation and alkaline phosphatase activity of human osteoblastic SaOS-2 cell line.

Tumor necrosis factor (TNF) alpha and TNF beta both inhibited proliferation of cultured human osteoblastic SaOS-2 cells. TNF alpha also inhibited alkaline phosphatase (ALP) activity in the cells. The TNF alpha-induced inhibition of proliferation and ALP activity was further potentiated by interferon (IFN) gamma. These findings indicate that human SaOS-2 cells, fulfilling several criteria for osteoblasts, respond to TNF alpha and IFN gamma, resulting in decceleration of their maturation.

Alkaline Phosphatase↗

PubMed1990

[Visible-light initiator system using thiobarbituric acid derivatives with methyl substituent].

Seven 2-thiobarbituric acid derivatives with methyl substituents were synthesized. Experimental visible-light curing resins were prepared using these compounds as a reducing agent in the dl-camphorquinone (CQ)-reducing agent initiator system. The effects of methyl substitution for thiobarbituric acid on initiation behavior of CQ-thiobarbituric acid initiator system were examined by analysis of polymerization of triethylene glycol dimethacrylate (3 G) in DSC and depth of cure. The solubility of thiobarbituric acid derivatives in 3 G was markedly changed by the introduction of the methyl group. Although the methyl group substitution at position 1 (3) in thiobarbituric acid improved the solubility of the acid in 3 G, it did not enhance the initiation ability. Maximum exothermic rate, time at maximum exothermic peak, amount of insufficiently polymerized layer and depth of cure were significantly improved by the introduction of one methyl group at the position 5. Thus the initiation ability was enhanced by the substitution. However, the introduction of two methyl groups at position 5 did not promote polymerization, but the inhibitory effect became apparent as the concentration of the reducing agent was increased.

Composite Resins↗

PubMed1990

[Study on visible-light curing soft resins consisting of fluoropolymers. 2. Effect of fluoroalkyl alpha-fluoroacrylate monomers].

New experimental visible-light cured soft resins were prepared by combining a vinylidene fluoride/hexafluoropropylene copolymer (2-6 F), or a vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer (2-4-6 F) with 2,2,3,3-tetrafluoropropyl alpha-fluoroacrylate (4 FFA), 2,2,3,3,3-pentafluoropropyl alpha-fluoroacrylate (5 FFA), 2,2,3,3,4,4,5,5-octafluoropentyl alpha-fluoroacrylate (8 FFA), or 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl alpha-fluoracrylate (12 FFA). Some properties of the resins prepared were measured to determine whether they would be candidate materials for the soft denture liner. Water contact angles increased with the increase in the number of fluorine atoms contained in the monomers: 85-90 degrees in 4 FFA, 90-93 degrees in 8 FFA, and 92-93 degrees in 12 FFA. Softer resins were obtained with 2-4-6 F, especially by the combination with 8 FFA giving the softest resin with a hardness of 43-46 (JIS A). Water sorption after 10 weeks was considerably low: 0.4-2%: 0.4-0.9% in 4 FFA/2-6 F and about 2% in 8 FFA/2-4-6 F. Solubility was 0.2-0.4% in the resins with 4 FFA and 1.0-1.4% with 8 FFA or 12 FFA. Amount of residual monomer was low, and the maximum was 0.4% in the resin with 12 FFA. Thus hardness and water sorption of the resins prepared were superior to those of the commercial soft materials.

Denture Liners↗

PubMed1990

[Study on visible-light curing soft resins consisting of fluoropolymers. (3) Application of low molecular weight fluoropolymer].

New experimental visible-light cured soft resins were prepared by combining a low molecular weight vinylidene fluoride/hexafluoropropylene copolymer (2-6 FL), or vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer (2-4-6 FL) with 2,2,3,3-tetrafluoropropyl alpha-fluoroacrylate (4 FFA), or 2,2,3,3,4,4,5,5-octafluoropentyl alpha-fluoroacrylate (8 FFA). Some properties of the resins prepared were measured to determine whether they would be candidate material for a soft denture liner. Water contact angle was 90-92 degrees with 4 FFA, and 90-94 degrees with 8 FFA. The resins combined with 2-4-6 FL were sufficiently soft: 42-46 (JIS A hardness) in 4 FFA, and 33-39 in 8 FFA. Generally the hardness decreased by 5-10 with the use of a low molecular weight of fluoropolymer. Water sorption after 10 weeks was 0.8-1.2% in 2-6 FL/4 FFA, 1.3-1.7% in 2-6 FL/8 FFA, about 1% in 2-4-6 FL/4 FFA, and about 2% in 2-4-6 FL and 8 FFA. Solubility was 0.4-0.5% in 2-6 FL/4 FFA, 0.3-0.4% in 2-4-6 FL/4 FFA, 1.5-1.9% in 2-6 FL/8 FFA, and 1.1-1.5% in 2-4-6 FL/8 FFA. Amount of residual monomer was very low, and the maximum was 0.1%. Tensile strength of the resins was reduced to 40-70% of that of the similar resins obtained in the previous study. Thus softer resins could be prepared by using lower molecular weight fluoropolymers.

Denture Liners↗

PubMed1990

[Study on visible-light curing soft resins consisting of fluoropolymers. 1. Effect of fluoroalkyl methacrylate monomers].

New experimental visible-light cured soft resins were prepared by combining 4 kinds of fluoroalkyl methacrylate monomers with a vinylidene fluoride/hexafluoropropylene copolymer, or a vinylidene fluoride/tettrafluroethylene/hexafluoropropylene copolymer. Some properties of the resins prepared were examined to determine their value as a soft denture liner material. Water contact angles were more than 90 degrees in all cases and increased with the increase in the number of fluorine atoms in the fluoroalkyl groups. Hardness (JIS A) was less than 50 for the softes resin. Water sorption after 10 weeks was 3-4.5 wt %. Solubility 0.1-0.3 wt% and amount of residual monomer 0.2 wt% were very low. The properties of these new experimental resins were comparable or superior to the commercial soft materials available.

Acrylic Resins↗

PubMed1990

[Study on adhesion mechanism of MMA-TBBO resin to dentin. A model experiment using decalcified dentin].

As a model experiment to understand the mechanism of adhesion of the MMA-TBBO resin to dentin, MMA-TBBO was polymerized using a decalcified dentin sheet treated with aqueous citric acid (CA) solutions of copper fluoride (CF), ferric fluoride (FF), or ferric chloride (FC), which are usually used as treating agents in the bonding of the resin to dentin. The curing time for MMA-TBBO resin was considerably reduced on the decalcified dentin sheet treated with FC-CA, CF-CA or FF-CA at an appropriate concentration. Polymerization of MMA-TBBO resin was accelerated in the presence of a fluoride ion. Molecular weight of PMMA depended on the site of polymerization; PMMA polymerization inside the decalcified dentin sheet gave the highest and that outside gave the lowest molecular weight in the presence of an appropriate amount of ferric or cupric ion. These results suggested that ferric compounds adsorbed to decalcified dentin are involved in the polymerization of MMA and thus will influence the bond strength of the MMA-TBBO resin to dentin.

Acrylic Resins↗

PubMed1990

[New low temperature initiator system for dental adhesive resins. Application of peroxyesters with carboxyl group].

Adhesion between dentin and MMA resin was investigated using chemically activated initiator system consisting of 1,3,5-trimethyl-2-thiobarbituric acid, cupric salt, chloride ion, and tert.-butyl peroxymaleic acid (MA) with carboxyl group which usually has affinity to tooth. The adhesive strength of the MMA/PMMA resin to bovine dentin increased significantly to 8-10 MPa by addition of MA, while the adhesive strength was 4 MPa without MA. When the bonding broke at higher than 7 MPa, the adhesive resin layer usually fractured cohesively and the interfacial fracture did not occur. The bond strength obtained in this experiment was comparable to that obtained with MMA resin using TBBO and ferric ion initiator system which is known as the best initiator system for dentin available.

Acrylic Resins↗

PubMed1990

[Adhesion mechanism of MMA/TBBO resin containing 4-META to decalcified dentin].

As a model experiment to understand the mechanism of adhesion of the 4-META-MMA/TBBO resin to dentin, 4-META-MMA/TBBO was polymerized in the presence of decalcified dentin sheet treated with citric acid (CA) aqueous solution containing ferric chloride (FC). Curing time of MMA/TBBO resin was reduced by the addition of 4-META to MMA. Addition of 4-META increased molecular weight of PMMA. PMMA polymerized inside the decalcified dentin sheet was insoluble in acetone. PMMA obtained from the monomer liquid used in commercial Super-Bond C & B was all insoluble and no soluble fraction was obtained. These results suggested that 4-META accelerated polymerization of MMA-TBBO resin in the presence of ferric ion and was effective to enhance molecular weight of PMMA. These effects seemed to be related to high bond strength of Super-Bond with dentin.

Acrylic Resins↗

PubMed1990

[Acute myeloblastic leukemia and hepatocellular carcinoma following Waldenström's macroglobulinemia].

A 54-year-old man was admitted to our hospital for precise examination of pancytopenia in October 1988. He had been cut off his left femur and irradiated because of osteosarcoma in 1954. After 30 years, he was diagnosed as Waldenström's macroglobulinemia. Melphalan had been given 2 mg daily for 19 months until August 1988, when it was discontinued due to pancytopenia. Peripheral blood showed Hb 6.6 g/dl, platelet 40 x 10(3)/microliters, and WBC 2000/microliters with 33% blasts. Bone marrow showed normocellularity with 36% blasts. Although blasts were negative for peroxidase staining, surface marker analysis revealed myeloid (CD 13, CD 33) phenotypes. Chromosome analysis showed 45, XY, -7, inv (3). A CT scan of the liver showed a mass, 10 by 10 cm, compatible with hepatocellular carcinoma. He was treated with very low dose Ara-C without noticeable effect. Hepatic tumor gradually enlarged, and he died of hepatic failure. This is a rare case of quadruplicate malignancies. The chromosomal abnormality suggests that AML was secondary leukemia which might be associated with immunosuppression due to macroglobulinemia and/or melphalan therapy.

Carcinoma, Hepatocellular↗

PubMed1990

Immunohistochemical study of steroid hormones and an estrogen binding assay in malignant soft tissue tumors.

Immunohistochemically, the immunoreaction against 5 steroid hormone anti-sera (estradiol, estriol, cortisol, progesterone and testosterone) was examined in 39 cases with the malignant soft tissue tumors (fibrosarcoma: 8, malignant fibrous histiocytoma: 6, rhabdomyosarcoma: 10, leiomyosarcoma: 10, liposarcoma: 5). Seventeen cases revealed distinct immunostaining against at least 1 of the 5 steroid hormones. Immunostained tumor cells were more frequently distributed in the area where tumor cell infiltration was more invasive. The majority of the positive cases occurred in female cases. Furthermore, the existence of estrogen receptor (estrogen binding activity) was examined histochemically in 39 cases and it was detected in 8. We concluded that steroid hormones might be closely related to tumor cell infiltration of some malignant soft tissue tumors.

Adolescent↗

PubMed1990

Lectin histochemical studies on renal tumors.

Histochemical characteristics on lectin binding of 16 cases of nephroblastoma and of 57 cases of renal cell carcinoma were studied on those of six embryonal and fetal kidneys in 4 to 24 gestational weeks and in six normal adult kidneys using four biotinylated lectins (PNA, LTA, SBA and UEA-1), which show segment specific binding for normal nephron. In normal nephrogenesis, Gal beta 1-3 GalNAc (PNA receptor) appeared at first in developing tubuli of the metanephros at 10 gestational weeks, and remained positive in proximal tubuli of 13 gestational weeks, where the Lewis X antigen (LTA receptor) emerged. In adult kidneys, Gal beta 1-3 GalNAc distributed along distal tubuli and collecting ducts and not in proximal tubuli. Type 2 H antigen (UEA-1 receptor) was confined to collecting ducts. In nephroblastomas, positive reaction to these lectins were almost exclusively confined to tubular structures. Gal beta 1-3 GalNAc was constantly positive there. Intensely positive stain of Lewis X antigen was observed in three cases of histologically well differentiated type. Lewis X antigen positive tubuli co-expressed Gal beta 1-3 GalNAc. There were six type 2 H antigen positive cases showing differentiation toward ureteric bud or collecting ducts. In view of the cell surface glycosylation, regular differentiation of fetal renal tubuli was also retained in nephroblastomas according to their degree of histological differentiation. In renal cell carcinoma, Gal beta 1-3 GalNAc was positive in 49% (28/57) and Lewis X antigen was positive in 54% (31/57). Type 2 H antigen was completely negative. In contrast to the nephroblastoma, there was no correlation between histological features and lectin binding patterns in renal cell carcinoma.

Adult↗

PubMed1990

[Konno procedure for congenital aortic valve stenosis with pulmonary valve stenosis].

Although aortic and pulmonary valve stenosis are among the most common congenital heart defects, the combination of both aortic and pulmonary valve stenosis in the same patient appears to be very uncommon. Accurate diagnosis of combined valvular stenosis is imperative prior to surgical correction, otherwise surgery of one of the lesions may result in an insufficient hemodynamic improvement. A seven-year-old girl with congenital aortic and pulmonary valve stenosis associated with hypoplastic aortic annulus underwent Konno's operation, pulmonary valvotomy and resection of anomalous muscle of the right ventricular outflow tract simultaneously. The operation was successfully performed and postoperative course was uneventful.

Aortic Valve Stenosis↗