Biomedical subjects

A Sakai

Publications and source records attributed to A Sakai.

At least 145 records · Page 8Linked to original sources

PubMed1996

Plasma cells composing plasmacytoma have phenotypes different from those of myeloma cells.

We describe one relapsed case of plasmacytoma of mandibular bone. The organs of relapse were liver and bone marrow. At relapse, monoclonal gammopathy (IgG-kappa) was observed without suppression of IgA and IgM. By immunostaining, the plasma cells of both the original mandibular bone and liver were positive for the same cytoplasmic immunoglobulin light chain kappa. The proliferative plasma cells in the bone marrow had the phenotype of CD38+, CD19+, and CD56- by flow cytometry and showed the presence of the rearranged IgH gene by Southern blotting. In addition, the zone of the Ig class of the patient's serum was not so sharply defined by zone electrophoresis. These results suggest that the characteristics of plasma cells of plasmacytoma are different from those of multiple myeloma.

ADP-ribosyl Cyclase↗

PubMed1996

Comparison of muscle force, muscle endurance, and electromyogram activity during an expedition at high altitude.

Handgrip force (HF), maximal pinch force (MF), muscle endurance (ME), and the median power frequency (MdPF) of the activity shown in the electromyogram (EMG) were studied at various altitudes in eight normal healthy subjects. MF and ME were measured between the index finger and thumb, and all measurements were obtained at altitudes ranging from 610 to 4860 m during an expedition in the Qinghai Plateau in China. With the change in altitude HF, ME, and MF showed no significant change. Compared to the MdPF at 2260 m on ascent, the MdPF at other altitudes showed a significant decrease (P < 0.01). Thus, we conclude that muscle performance (HF, MF, and ME) was not affected by the environment at high altitude. However, MdPF was affected and the mean MdPF at 610 m after the expedition did not recover to initial values of MdPF. We suggest these results may have been affected by fatigue and chronic exposure to the hypobaric hypoxic environment, since the members of the expedition party expressed feelings of sluggishness and fatigue after the expedition.

Acclimatization↗

PubMed1996

Is the presence of hyperlipidemia associated with impairment of endothelium-dependent neointimal relaxation after percutaneous transluminal coronary angioplasty?

To determine whether hyperlipidemia affects the endothelium-dependent vasomotor response along the dilated vessel after percutaneous transluminal coronary angioplasty (PTCA), we evaluated 32 patients with one-vessel disease, 3-6 months after successful PTCA without restenosis. Fourteen patients had mild stenotic lesions not subjected to PTCA (non-PTCA sites) in addition to the PTCA sites. Vessel diameter changes at 32 PTCA and 36 non-PTCA sites were assessed by quantitative angiography, before and after intracoronary injection of acetylcholine (20 micrograms to the right and 50 micrograms to the left coronary artery) and of nitroglycerin (0.1-0.3 mg). The acetylcholine response ranged from 46% (dilation) to -100% (constriction). All coronary arteries were dilated in response to nitroglycerin, which suggested preservation of the function of vascular smooth muscle, and the presence of an abnormality in endothelial function in those patients with a constrictor response to acetylcholine. There was a negative correlation between the acetylcholine response and the serum total cholesterol level at PTCA sites (r = -0.37; P = 0.038) and at non-PTCA sites (r = -0.46; P = 0.005). These findings indicate that hyperlipidemia is associated with a loss of endothelium-dependent vasodilation, not only at non-PTCA but also at PTCA sites, at which restoration of endothelial function might have occurred. They also suggest that hyperlipidemia may be related to the functional state of the regenerated endothelium at sites where PTCA had been previously performed.

Acetylcholine↗

PubMed1996

Protection against septic shock in mice with SJC13, an azaindolidine derivative that is a cell adhesion molecule inhibitor.

An azaindolidine derivative, SJC13, selectively inhibits expression and mRNA synthesis of E-selectin and vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVEC) stimulated with lipopolysaccharide (LPS). The present experiments were performed to determine the in vivo effects of SJC13 against the lethality of LPS. In a mouse model of septic shock, intravenous administration of SJC13 5 min prior to LPS injection prevented significantly the lethality at doses of 3 mg/kg and 10 mg/kg. The prophylactic effect was dose-dependent. When injected up to 1 h after LPS injection, SJC13 inhibited significantly the lethality. Neutrophil emigration into lung tissues during sepsis induced with LPS, as assessed by lung myeloperoxidase (MPO) content and histological examination, was significantly prevented by SJC13 administration. These data demonstrate that SJC13 has therapeutic anti-inflammation potential in vivo.

Animals↗

PubMed1996

Inhibition of endothelial cell adhesion molecule expression with SJC13, an azaindolidine derivative, in vitro.

Stimulation of cultured human umbilical vein endothelial cells (HUVEC) with lipopolysaccharide (LPS) induces adherences for human promyelocytic cell line HL60. Adherence of HL60 cells to HUVEC stimulated with LPS for 4h was completely inhibited by pretreatment with SJC13, an azaindolidine derivative. The mechanism whereby SJC13 inhibits the adhesiveness of HUVEC was investigated. Pretreatment of SJC13 inhibited LPS-induced expression of E-selectin and vascular cell adhesion molecule-1 (VCAM-1), but not intercellular adhesion molecule-1 (ICAM-1), in HUVEC, determined by flow cytometry and cellular enzyme-linked immunosorbent assay (cell-ELISA). The inhibitory activity was concentration dependent between 62.5 and 1,000 micrograms/ml. SJC13 also selectively inhibited LPS-induced increases in E-selectin and VCAM-1 mRNAs, indicating that the action of SJC13 is to inhibit synthesis of these molecules. These data demonstrate that SJC13 is capable of selectively inhibiting the expression of E-selectin and VCAM-1, but not ICAM-1, in endothelial cells.

Base Sequence↗

PubMed1996

Giant degenerative perineurial cell tumor.

We report a case of giant perineurial cell tumor, probably benign, with extensive degenerative changes. The secondary changes were reminiscent of those in giant ancient neurilemomas. To our knowledge, there has been no documentation of the imaging features in perineurioma. The MR findings of the present tumor, especially on T2-weighted images, correlated well with the histologic appearance.

Aged↗

PubMed1996

Collateral channels that develop after an acute myocardial infarction prevent subsequent left ventricular dilation.

OBJECTIVES: We sought to evaluate the effect of collateral channels that develop late after a first anterior myocardial infarction on left ventricular dilation and function. BACKGROUND: Collateral channels in an infarct-related artery may develop long after occlusion of the artery. Well visualized collateral channels that appear immediately after a myocardial infarction reduce infarct size and preserve left ventricular function. However, the functional significance of collateral channels that develop late after myocardial infarction has not been evaluated in terms of left ventricular function. METHODS: We studied 21 patients with a first anterior myocardial infarction and an infarct-related artery that remained totally occluded after reperfusion therapy and did not reopen within 1 month of infarction. No collateral channels were observed during the acute period. Patients were classified into two groups according to the extend of collateral formation 1 month after infarction: group C, patients with well developed collateral channels (n = 11), and group NC, patients with absent or poorly developed collateral channels (n = 10). Infarct size was determined by peak creatine kinase activity and thallium-201 single-photon emission computed tomography. Global and regional left ventricular function and left ventricular volumes were assessed by left ventriculography. These measurements were identical in both groups 1 month after infarction. Left ventricular function was reevaluated after 2.12 +/- 0.79 years (mean +/- SD). RESULTS: There were no significant changes in global and regional left ventricular function between the two groups during the long-term follow-up period. However, the end-diastolic volume index of group NC increased from 71 +/- 14 to 85 +/- 19 ml/m2, whereas that of group C decreased from 64 +/- 18 to 59 +/- 12 ml/m2. This important change during the long-term follow-up period resulted in a significant difference (p = 0.0006) in the end-diastolic volume index between the groups 2 years after onset (p = 0.002), whereas 1 month after infarction the difference was not significant (p = 0.36). A similar pattern was observed for the end-systolic volume index (group C: 38 +/- 16 to 35 +/- 14 ml/m2; group NC: 45 +/- 12 to 58 +/- 18 ml/m2, p = 0.018). The power of the tests to detect the observed differences showing nonsignificant results ranged from 0.05 to 0.38, whereas the power of the tests indicating a significant difference in end-diastolic and end-systolic volume indexes was >0.88. CONCLUSIONS: Collateral channels that develop after a myocardial infarction do not reduce the infarct size or prevent left ventricular dilation within 1 month of infarction. In contrast, such collateral channels prevent subsequent ventricular dilation and the deterioration of left ventricular function over 2 years. However, our results may have been biased because of the small number of patients.

Aged↗

PubMed1996

Bone marrow capacity for bone cells and trabecular bone turnover in immobilized tibia after sciatic neurectomy in mice.

Trabecular bone turnover and bone marrow capacity for the development of bone cells in the tibia were assessed after sciatic neurectomy (NX) in mice. The right hindlimbs of 6-week-old DDY mice were neurectomized and left hindlimbs were sham-operated and served as NX controls. Histomorphometrical analyses of the trabecular bone of the proximal tibia demonstrated the initial decrease in bone formation rate for the first 14 days and the subsequent increase in osteoclast surface for the next 14 days. The number of adherent stromal cells per tibia obtained for the NX limbs was reduced on days 7 and 10 postsurgically, and then recovered on day 12. However, the alkaline phosphatase activity of the cells was persistently depressed. The formation of osteoclast-like multinucleated cells in the marrow cultures obtained from NX limbs at days 10, 12, and 14 showed a significant increase in the medium containing parathyroid hormone (PTH). The number of colonies cultured for colony forming units-fibroblastic (CFU-f) that developed from the marrow cells did not differ in the NX and the contralateral limbs at any time during the period. On the other hand, the number of colonies cultured of colony forming units for granulocytes and macrophages (CFU-GM) was markedly increased for both the NX and the contralateral tibiae at days 12 and 14. This study clearly demonstrates that there are two stages in the development of osteopenia after NX. During the first 14 days, trabecular bone formation and number of marrow stromal cells are reduced. In the second 14 day period, the trabecular osteoclast number is increased and osteoclast formation from the bone marrow cells is enhanced in the presence of PTH. However, neither the CFU-f nor the CFU-GM assay could identify the changes in osteogenic or osteoclastogenic potential of the bone marrow. These in vitro assays provide limited information on the shifts in bone marrow cell lineages and the local environment producing osteopenia in the immobilized limb in vivo.

Alkaline Phosphatase↗

PubMed1996

Isolation and developmental expression of male reproductive organ-specific genes in a dioecious campion, Melandrium album (Silene latifolia).

The dioecious campion Melandrium album (Silene latifolia) has sex chromosomes, and male and female plants form different unisexual flowers. The very youngest buds have both sex organs but the development of either a gynoecium in the male bud or stamens in the female bud is arrested as the bud matures. To examine the molecular mechanism of male-specific differentiation, a cDNA library from male buds was differentially screened with cDNA from male and female buds. Four male reproductive organspecific cDNAs (corresponding to genes designated MROS1, MROS2, MROS3 and MROS4, respectively) were isolated. Northern blot analysis showed that the transcripts of MROS genes were expressed only in male reproductive organs. The transcripts of MROS3 and MROS4 accumulated in the early buds, while transcripts of MROS1 and MROS2 accumulated in the late buds and in the anthers of open flowers. The putative MROS2 protein has glycine-rich regions, while the putative MROS3 protein exhibits no similarity to known proteins. Genomic Southern blot analysis showed that male and female genomes included MROS2 and MROS3 genes. Non-radioactive in situ hybridization revealed the localization of the transcripts of MROS2 and MROS3 in male buds. MROS3 mRNA was distributed throughout the tapetum. After MROS2 mRNA had accumulated in the epidermis and the endothecium near the stomium, the accumulation of the mRNA increased significantly in the mature pollen. MROS2 seems to be a novel anther-specific gene that functions in dehiscence of anthers and the maturation of pollen.

Amino Acid Sequence↗

PubMed1996

Cloning of cDNA encoding for a novel isozyme of fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase from human placenta.

Two independent cDNA clones encoding fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase were isolated from a human placental cDNA library. The deduced amino acid sequences showed that one of the clones, 2K-1, was almost identical to the rat testis isozyme and the other, 2K-3, was different from any known isozymes expressed in mammalian tissues. The results of Southern blot analysis suggested that clones 2K-1 and 2K-3 were encoded as single copy genes and located in different parts of the genome. Since open reading frames of the cDNA clones were not complete, we obtained the 5'-end of the clone 2K-3 cDNA using the 5'-rapid amplification of cDNA end method. The entire cDNA (HP; 1,756 bp) had a coding capacity of 519 amino acids (M(r) = 59,410), and putative phosphorylation sites for protein kinases A and C on the C terminus. Northern blot analysis using a fragment of the HP as a probe showed that a major band of 5.4 kb, significantly different in size from known isozyme mRNAs such as liver (2.1 kb), muscle (1.9 kb), heart (4.0 kb), and testis (2.0 kb), was present in poly(A)+RNA preparations of human first trimester and term placentae. These results strongly suggested that this 5.4 kb mRNA codes a novel isozyme of fructose 6-phosphate,2-kinase/fructose 2,6-bisphosphatase.

Amino Acid Sequence↗

PubMed1996

Effects of transforming growth factor beta s and basic fibroblast growth factor on articular chondrocytes obtained from immobilised rabbit knees.

OBJECTIVE: To clarify the effects of transforming growth factor beta 1 (TGF beta 1), TGF beta 2, and basic fibroblast growth factor (bFGF) on cell proliferation and proteoglycan (PG) synthesis in articular chondrocytes obtained from immobilised rabbit knees. METHODS: The right knees of rabbits were immobilised in full extension for up to 42 days using fiberglass casts. Specimens for histology were stained with safranin O. Chondrocytes were isolated from the weight bearing regions of the femur and tibia of the immobilised knees and cultured with combinations of growth factors. Cell proliferation and PG synthesis were determined by 3H-thymidine and 35S-sulphate incorporations. RESULTS: Histological study revealed loss of metachromasia in the articular cartilage at seven days, fissuring and cell clusters at 28 days, and loss of cartilage layers 42 days after immobilisation. Radioisotope assay of the chondrocytes revealed no remarkable change in DNA synthesis in the presence of either TGF beta 1 or TGF beta 2 alone. bFGF markedly stimulated cell proliferation in specimens obtained 0 to seven days after immobilisation. The combination of either TGF beta 1 or TGF beta 2 with bFGF had a synergistic effect, inducing significant increases in DNA synthesis four, seven, and 14 days after immobilisation. PG synthesis by chondrocytes from immobilised joints was not significantly altered by these agents. CONCLUSION: TGF beta 1 or TGF beta 2 in combination with bFGF exert synergistic effects on cell proliferation in articular chondrocytes obtained from the rabbit knee during the early days after immobilisation by a cast. These results suggest a critical role of cytokine combinations in the development of articular cartilage degeneration after immobilisation.

Animals↗

PubMed1996

Adenine nucleotides via activation of ATP-sensitive K+ channels modulate hypoxic response in rat pulmonary artery.

We examined the role of ATP-sensitive K+ channels in hypoxic pulmonary vasoconstriction, using isolated rat pulmonary arterial rings. Isolated rat pulmonary arterial rings displayed a rapid contraction followed by relaxation under hypoxic conditions. The ATP-sensitive K+ channel blocker glibenclamide (concentration > 1 microM) or a hyperglycemic buffer (15 mM glucose) attenuated the hypoxic relaxation in a dose-dependent manner but did not affect the hypoxia-induced contraction. To examine the relationship between hypoxia, energy, and redox state, intracellular levels of adenine nucleotides and pyridine coenzymes were determined by high-performance liquid chromatography in freeze-dried isolated rat pulmonary arteries at three time points (0, 4, and 10 min) before and during hypoxia. Hypoxia time dependently decreased the ATP content and the ATP-to-ADP ratio and increased the ADP and the AMP content in association with a rapid increase in the NADH and the NADH-to-NAD+ ratio. Hyperglycemic buffer (15 mM glucose) suppressed the hypoxia-induced changes of the adenine nucleotides (the decrease of the ATP content and the ATP-to-ADP ratio) but did not affect the hypoxia-induced changes of the NADH and the NADH-to-NAD+ ratio. Hypoxia did not affect the NADP+ or the NADPH content of pulmonary arteries. These findings indicate that an ATP-sensitive K+ channel regulates the tone of rat pulmonary arteries. Furthermore, an imbalance of the energy state may be involved in ATP-sensitive K+ channel activation during hypoxic vasorelaxation.

Adenine Nucleotides↗

PubMed1996

Influence of hypoxia and pulmonary air embolism on lung injury in perfused rat lungs.

We investigated the influence of low oxygen ventilation, air-bubble infusion into the pulmonary artery and their synergistic effect on pulmonary hemodynamics and microvascular permeability in isolated perfused rat lungs. Pulmonary arterial pressure was significantly increased by 70 min of ventilation with 3% O2 (hypoxia, group H); by 0.2-ml air-bubble infusion (pulmonary air embolism, group AE), and by 0.2-ml air-bubble infusion and 70 min of 3% O2 ventilation (hypoxia and pulmonary air embolism, group H & AE) compared with that of a control group (0.2 ml saline infusion, group C). Neither total (TPR) nor arterial (Ra) pulmonary vascular resistance in group H showed any difference compared to control values. TPR and Ra in groups AE and H & AE were significantly higher than those in group C. However, there was no significant difference in TPR or Ra between groups AE and H & AE. The pulmonary capillary fluid filtration coefficient, dry lung to wet lung weight ratio and white blood cell count in the perfusate of group H were not changed, while those of the groups AE and H & AE were significantly increased compared to those of controls. However, there was no significant difference in these values between groups AE and H & AE. Since hypoxia did not damage isolated perfused rat lungs, as determined by hemodynamics and permeability, nor enhance lung injury caused by air embolism, it was suggested that air embolism contributed more to high-altitude lung injury than low oxygen.

Analysis of Variance↗

PubMed1996

Effect of the 21-aminosteroid U-74006F on antigen-induced bronchoconstriction and bronchoalveolar eosinophilia in allergic sheep.

U-74006F, a non-glucocorticoid 21-aminosteroid, has been developed as an inhibitor of iron-dependent lipid peroxidation. This class of compounds has been shown to prevent antigen-induced eosinophil accumulation in the lungs. In this study, Ascaris-sensitive, "dual-respondent" sheep (showing both immediate (IAR) and late (LAR) asthmatic response) (n = 6) were used to assess the effect of U-74006F on antigen-induced bronchoconstriction and airway inflammation and reactivity 8 h after antigen challenge. Antigen provocation induced dual-phase bronchoconstriction, bronchoalveolar eosinophilia and airway hyperreactivity (AHR) to methacholine. Throughout the experiment, intravenous administration of the drug significantly reduced the IAR and inhibited the LAR along with the inhibition of eosinophil influx, but did not inhibit the increase in airway reactivity observed 8 h after antigen challenge. Post-antigen challenge treatment with U-74006 from 3 h after antigen challenge also significantly reduced the LAR and bronchoalveolar eosinophilia, although the degree of inhibitory effect was milder. The development of the LAR appeared to be dependent on eosinophil recruitment into the lungs. These findings suggest that lipid peroxidation is involved in antigen-induced bronchoconstriction and eosinophil recruitment into the lungs, and that the inhibitor U-74006F may be an effective drug for the treatment of bronchoconstriction and airway inflammation characterized by eosinophil infiltration in asthmatics.

Allergens↗

PubMed1996

Variability of mitochondrial subgenomic molecules in the meristematic cells of higher plants.

MtDNAs from BY-2 cells and rice root were analyzed by random amplified polymorphic DNA (RAPD) assay and Southern hybridization analysis. A number of differences were observed in the RAPD patterns amplified from mtDNAs sampled at different phases of the BY-2 cell culture. RAPD fragments also varied with the template DNAs derived from various areas of rice root tip. When a RAPD fragment was hybridized to restriction fragments of whole DNAs, isolated from the distal area of the apical meristem and differentiated elongation zone of a root, two distinct stoichiometric differences were observed in the hybridization signals. This suggests that the organization of mt-genome in prototypic cells in the root apical meristem differs from that found in the differentiated cells.

Blotting, Southern↗

PubMed1996

[Report of a case with re-mitral valve replacement for Björk-Shiley Delrin disc valve prosthesis--disc wear of the Delrin disc 20 years after implantation].

We reported a patient in whom slight congestive heart failure gradually developed 20 years after mitral valve replacement with a Delrin disc Björk-Shiley valve prosthesis. Although no evident cause of prosthetic valve malfunction could be detected preoperatively, the mitral prosthesis was excised and replaced uneventfully with a 29 mm St. Jude Medical valve prosthesis. At gross inspection, marked wears of the Delrin disc surface and strut shaped indentations were present. These disc variance, occurred much earlier than initially predicted by Dr. Björk, allowed prosthetic valve malfunction. The patient with this specific model should be carefully followed-up, if necessary, performed reoperation.

Heart Valve Prosthesis↗

PubMed1996

Wound healing effect of malotilate in rats.

The wound healing effect of malotilate (CAS 59937-28-9, NKK-105) was investigated by using an excisional skin-wound model produced on the back of normal and healing-impaired (induced by prednisolone pretreatment) rats. The rapid decrease in the square measure of wound areas and the improvement in the histological evaluation clarified that 0.3% and 1% cream preparations of malotilate were obviously effective in accelerating spontaneous healing in the normal rats. The accelerative effect of malotilate cream preparations was likely superior to that of an ointment containing 5% deproteinized calf blood extract used as a reference agent. The same effect was also observed in the healing-impaired rats. The histological findings revealed that a thicker and more cellular granulation tissue, which in turn created an adequate bed for rapid re-epithelization, was formed in the malotilate-treated animals. Acceleration of granulation tissue formation by malotilate was also supported by the cotton pellet implantation method. It is concluded from these results that malotilate seems to be a promising agent for topical wound therapy.

Administration, Topical↗

PubMed1996

[Sinus venosus atrial septal defect: report of two cases with successful repair by the Vargas' procedure].

Two cases of sinus venosus atrial septal defect with partial anomalous of right upper pulmonary venous drainage into superior vena cava treated by the Vargas' procedure were reported. These patients were 5 and 6 years old. Post operative courses were uneventful, and results of postoperative hemodynamic and clinical evaluation were encouraging. The Vargas' procedure is useful method for a reconstraction of the anomaly in childhood because of use of the autologus tissues. Though long-term fate of this procedure is still uncertain. Then, we consider that a long-term follow up is necessary.

Cardiac Surgical Procedures↗