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Biomedical subjects

M Nakajima

Publications and source records attributed to M Nakajima.

At least 271 records · Page 15Linked to original sources
PubMed1999

Endothelium-independent vascular relaxation mediating ETB receptor in rabbit mesenteric arteries.

Vascular response mediating endothelin (ET)B receptor was studied using isolated rabbit mesenteric arteries. ET-1 (0.1-30 nM) caused a concentration-dependent contraction, whereas ET-3 >100 nM caused only weak contraction. Up to 1 microM of sarafotoxin S6c showed no contraction. In arteries precontracted with phenylephrine, ET-3 (0. 03-1 nM) caused a concentration-dependent relaxation, which was not affected by endothelium denudation. The ET-3-induced relaxation was antagonized by BQ-788 and PD-142893 but not by BQ-123 in the endothelium-denuded arteries. Treatment with indomethacin but not with NG-nitro-L-arginine methyl ester completely inhibited the relaxation. ET-3 stimulated the release of 6-keto-PGF1alpha and PGE2 from the endothelium-denuded arteries. ET-3 also significantly increased cAMP content but not cGMP content in the arteries. Radioligand-binding studies using serial sections of the artery revealed the expression of not only ETA but also ETB receptors in the smooth muscle layer of the arteries. These results suggest that ET-3 activates ETB receptor in smooth muscle cells of rabbit mesenteric artery, producing vasodilator prostaglandins from arachidonic acid probably via a catalysis of cyclooxygenase, which accumulates cAMP in subendothelial tissues and produces relaxations.

Animals↗
PubMed1999

Biological implications of growth factors on the mechanism of invasion in gynecological tumor cells.

We investigated the effects of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) on migration, invasion and proteinase expression of gynecological cultured cancer cells (SKG-IIIb cervical squamous cell carcinoma, OMC-4 cervical adenocarcinoma, SNG-M endometrial adenocarcinoma and OMC-3 ovarian adenocarcinoma), and whether these growth factors affect thymidine phosphorylase/platelet-derived endothelial cell growth factor expression of tumor cells. Tumor cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were stimulated by 0.1-10 nM EGF and TGF-alpha in a concentration-dependent manner. The zymography of tumor-conditioned medium showed that the treatment of tumor cells with EGF and TGF-alpha resulted in the increase of type IV collagenases, stromelysin and urokinase-type plasminogen activator which was partly confirmed by immunoblot analysis. The expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor which has angiogenic activity, was also upregulated by these growth factors. These results suggest that EGF and TGF-alpha act as positive regulators on the invasion process of gynecological tumor cells which may be associated with their stimulatory action on the motility of tumor cells, the expression of proteinases secreted by tumor cells and the angiogenic phenotype.

Adenocarcinoma↗
PubMed1999

Immunogold labelling of cytokines in glomeruli in children with various renal diseases.

Precise localization of cytokines such as transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 and IL-6 was observed in glomeruli using immunogold electron microscopy in 21 children with various types of renal diseases. The distribution pattern of these cytokines, as well as immunoglobulins, C3c and fibrinogen (Fg), was essentially confined to the electron-dense deposits (EDDs) regardless of their location. Frequency of positive labelling of each cytokine was different among various types of renal disorder, that is, TGF-beta was found mainly in lupus nephritis (LN), membranous nephropathy and IgA nephropathy, TNF-alpha in LN, and IL-1 in Henoch-Schönlein purpura nephritis. IL-6 was detected only in 1 case of LN. TNF-alpha was also found in the cytoplasm of glomerular epithelial cells. Furthermore, in order to evaluate the relation of cytokines to mesangial expansion, extracellular matrix components such as type IV collagen, laminin and fibronectin were stained. The result was that there was no significant correlation between the signal intensity or distribution pattern of cytokines and that of extracellular matrix components. These findings indicate that these cytokines could be associated with the formation of EDDs together with immunoglobulins, C3c and Fg. The involvement of each cytokine in renal pathophysiology might also depend upon the type of renal disease. They also raise the possibility that the glomerular epithelial cells might produce or absorb TNF-alpha. However, these results did not show significant correlation between cytokine involvement and mesangial expansion.

Biopsy↗
PubMed1999

Effect of moist vs. dry bonding to normal vs. caries-affected dentin with Scotchbond Multi-Purpose Plus.

Recent research in dentin bonding demonstrated the superiority of moist bonding over dry bonding on normal dentin, but it is unclear if this technique is also superior in bonding to caries-affected dentin. The purpose of this study was to evaluate the SEM appearance and bond strength of Scotchbond Multi-Purpose Plus (SMPP) to normal vs. caries-affected dentin bonded under moist vs. dry conditions, with and without polyalkenoic acid in the primer. Extracted carious human third molars were ground down by means of 600-grit SiC paper until the carious dentin no longer stained with caries detector solution. The flat surfaces were then primed, bonded, and built up with resin composite. After soaking in water for 1 day, the teeth were serially sectioned vertically into 5 or 6 slabs 0.7 mm thick. The bonded caries-affected areas were isolated by means of an ultrafine diamond bur to create an hourglass configuration with a cross-sectional area of 0.9 mm2. Bonded normal dentin was isolated the same way. Each specimen was attached to a Bencor device and tested in tension to failure. SMPP bonds to dry, normal dentin were only half as strong (21+/-10 MPa, x +/- SD) as those made to moist, normal dentin (42+/-9 MPa, p<0.01). There was no significant difference between bonds made to normal vs. caries-affected dentin by means of the moist technique (42+/-9 vs. 48+/-4 MPa, respectively). Removal of the polyalkenoic acid from the primer lowered (p<0.05) the bond strength of SMPP to caries-affected dentin (38+/-8 MPa). The benefits of moist bonding extend to caries-affected dentin. The polyalkenoic acid in the SMPP primer contributes to the high bond strength that can be achieved to caries-affected dentin.

Analysis of Variance↗
PubMed1999

Preparation and application of anti-idiotypic antibody against anti-gibberellin A4 antibody.

A monoclonal anti-idiotypic antibody was raised against anti-gibberellin A4 (GA4) antibody, which recognizes biologically active gibberellins such as GA1 and GA4 specifically. Amino acid sequences of variable regions of both anti-GA4 and anti-idiotypic antibodies were analyzed. By using the property of the anti-idiotypic antibody to compete with GA1/4 in binding to the anti-GA4 antibody, we successfully applied the anti-idiotypic antibody to ELISA as a tracer for measuring GA1/4. The single-chain Fv (scFv) gene of the anti-idiotypic antibody was constructed, and scFv expressed in E. coli showed binding activity to anti-GA4 antibody. These results suggest the possible application of anti-idiotypic antibody as a handy and stable source of an enzymatic tracer for ELISA by production of fusion protein of the scFv and an appropriate enzyme.

Amino Acid Sequence↗
PubMed1999

Expression of a functional single-chain antibody against GA24/19 in transgenic tobacco.

An anti-gibberellin A24/19 single-chain Fv gene was constructed from gamma and kappa genes cloned from a hybridoma cell line producing monoclonal antibody against gibberellin A24/19, biosynthetic precursors of gibberellin A4/1 which are biologically active per se. The single-chain Fv gene was introduced into tobacco plants after the binding activity of the single-chain Fv expressed in Escherichia coli was confirmed. When the single-chain Fv expression is targeted to endoplasmic reticulum, the plants could accumulate the single-chain Fv protein with the antigen binding activity up to 3.6% of the total soluble protein. On the other hand, when the expression is targeted to cytosol, accumulation of the single-chain Fv protein was not detected at all. The dwarf phenotype of the transgenic plants expressing the single-chain Fv protein, together with the preliminary analytical data indicating a decreased level of gibberellin A1 in the dwarf transgenics, suggested that the single-chain Fv decreased the concentration of bioactive gibberellins by trapping and inhibiting the metabolism of gibberellin A24 and/or A19 to gibberellin A4 and/or A1.

Antibodies, Monoclonal↗
PubMed1999

Difference in the incidence of cough induced by angiotensin converting enzyme inhibitors: a comparative study using imidapril hydrochloride and enalapril maleate.

To compare the incidence of cough between two angiotensin converting enzyme (ACE) inhibitors, imidapril and enalapril, comparative crossover study was performed in 489 patients (228 men and 261 females) with essential or renal parenchymal hypertension. Patients were randomly assigned to one of two treatment groups, a group receiving imidapril for 12 wk (Period I) followed by enalapril for 12 wk (Period II), and a group in which the order of drugs was reversed. The occurrence of cough during treatment was monitored by questionnaire in all cases. There were no differences in background characteristics between the two groups. The incidence of cough during Period I was 15.2% (32/210) in the group initially treated with imidapril (Group IE) and 38.6% (85/220) in the group initially treated with enalapril (Group EI), the difference being statistically significant (p < 0.001). During Period I, decrease in blood pressure was observed in 63.9% (115/180) of Group IE and 64.6% (115/178) of Group EI patients. In approximately half of the patients in Group EI who developed cough during Period I and in whom the treatment was subsequently switched to imidapril, cough subsequently disappeared. It was concluded that the incidence of cough was significantly less under imidapril than under enalapril treatment, while there was no difference in the antihypertensive effects of the two ACE inhibitors.

Administration, Oral↗
PubMed1999

Effects of superoxide dismutase on the acetylcholine-induced relaxation response in cholesterol-fed and streptozotocin-induced diabetic mice.

High concentration of acetylcholine (ACh) caused a rapid and long lasting relaxation response in age-matched controls, whereas this response was significantly weaker in streptozotocin (STZ)-diabetic and cholesterol fed mice. The levels of basal and ACh-stimulated cyclic GMP in the aorta was also significantly smaller in STZ-diabetic and cholesterol-fed mice. The attenuated relaxation responses to ACh in both STZ-diabetic and cholesterol-fed mice were ameliorated by the chronic administration of cholestyramine. A prior incubation of aortic strips with superoxide dismutase (SOD, 60 U/ml) improved the recovery phase of the relaxation of diabetic aorta after single administration of ACh, whereas SOD had no effects on ACh-induced relaxation of aortic strips from cholesterol fed mice. These results suggest that superoxide anion may be responsible for an impairment of endothelium-dependent relaxation of aorta from STZ induced diabetic mice. It is further suggested that impairment of endothelium-dependent relaxation in STZ-diabetic and cholesterol fed mice may be caused by different mechanisms.

Acetylcholine↗
PubMed1999

Preoperative identification of meningiomas that are highly likely to recur.

OBJECT: Although generally they are well-circumscribed benign tumors, meningiomas recur even after complete removal. The aims of this study are to identify preoperatively groups of patients who have a high risk of meningioma recurrence by reviewing their clinicoradiological features and to plan appropriate treatments. METHODS: One hundred one patients who underwent macroscopically complete removal of meningiomas were observed postoperatively for at least 5 years or until tumor recurrence. Preoperative radiological findings and clinical characteristics were assessed. Fifteen meningiomas recurred during the follow-up period, which extended to a maximum duration of 18 years. On univariate analysis, tumor size and shape, relation to the major sinuses, calcification, bone changes, and characteristics of the tumor-brain interface were significant predictive factors for recurrence. Patient age and gender were not deemed significant. Multivariate analysis revealed that only the shape of the tumor was significant; both "mushrooming" and lobulated meningiomas were more likely to recur than round ones. Recurrences most frequently occurred at the edge of the dural resection after a Simpson Grade I removal, whereas local recurrences were predominant after a Simpson Grade II or III removal. CONCLUSIONS: Meningiomas with mushrooming or lobulated shapes should be treated more aggressively with a wider dural excision. This is not usually necessary for round tumors, although it may be beneficial in younger patients.

Adult↗
PubMed1999

Cervical cord compression caused by a pillow in a postlaminectomy patient undergoing magnetic resonance imaging. Case report.

A 66-year-old man, who had undergone osteoplastic laminectomy for posttraumatic cervical myelopathy, underwent a second operation in which the replaced laminae were removed because of postoperative deep wound infection. Follow-up dynamic magnetic resonance imaging with flexion and extension views of the neck 1 year postsurgery demonstrated that the cervical cord was markedly compressed from behind in the extended position, although a wide subarachnoid space was observed in this region when the neck was in the flexed position. The cause of cord compression was the pillow that was placed underneath the patient's neck for maintaining the extended position, not the neck extension itself. This finding indicates that care must be taken during neuroradiological examination not to place a pillow under the neck of a patient who has undergone laminectomy. Nuchal compression could lead to cervical cord injury after laminectomy. Laminoplasty benefits the patient by protecting the cervical cord from secondary injury.

Aged↗
PubMed1999

[Present problems and future trend of antifungals for deep seated mycosis. Azole antifungal agents].

Azole antifungal agents are the most common drugs for the treatment of deep seated mycosis throughout the world, because of their favorable anti-fungal spectrum, pharmacokinetics and safety. However there are some weak points in each drug or class, such as emerging resistance or interactions with other drugs. Many new derivatives are now under pre-clinical and clinical evaluation and among them, voriconazole and SCH56592 are showing satisfactory results in their early clinical studies. At the same time, however the ability of doctors to make an appropriate and logical choice for use of these drugs also essential.

Animals↗
PubMed1999

[Brainstem segmental arrangement of sucking rhythm generators for trigeminal, facial and hypoglossal motoneurons].

Rhythmical sucking like activity (RSA) is known to be induced in the hypoglossal nerve (XII n) in an isolated brainstem-spinal cord preparation from newborn rats with bath application of N-methyl-D-aspartate (NMDA). Since natural sucking consists of well-coordinated rhythmical activities of the tongue, face, and jaw muscles, it is assumed that the trigeminal (V) and facial (VII) motoneurons would show rhythmical activities during the RSA. The purpose of this study was (1) to induce rhythmical activities in the V and VII ns in addition to XII n during bath application of NMDA, and (2) if they are induced, to locate the structures essential for generation of NMDA-induced rhythmical V, VII, and XII n activities using sectioning techniques. Experiments were performed on brainstem-spinal cord preparations isolated from newborn mice with or without the orofacial structure. Neural activities were recorded from the V, VII, and XII ns with suction electrodes. Movements of the tongue and jaw were recorded with a CCD camera system. It was found that (1) bath application of NMDA (5-20 microM) induced RSA in the V, VII, and XII ns, (2) it also induced rhythmical sucking-like movements of the jaw and tongue, and (3) after complete transections of the brainstem between the V and VII ns as well as at the pontomedullary junction, NMDA still induced the RSA in the V, VII, and XII ns. These results demonstrate that separate rhythm generators for rhythmical NMDA-induced activities in the V, VII, and XII motoneurons are located at the respective levels in the brainstem.

Animals↗
PubMed1999

Enzymatic 1-N-acetylation of paromomycin by an actinomycete strain #8 with multiple aminoglycoside resistance and paromomycin sensitivity.

An actinomycete strain #8 with multiple aminoglycoside (AG) resistance and paromomycin (PRM) sensitivity was examined for its capability of enzymatic modification of AGs. Cell free extracts from the strain converted all of the examined AGs including PRM in the presence of acetyl CoA. PRM was completely modified to at least two products (major and minor spots upon TLC) without significant reduction of the antibiotic activity of the reaction mixture. The structure determination and antibiotic assay of the purified major product revealed l-N-acetylPRM and its antibiotic activity (12% activity of PRM), indicating the existence of AAC(1). It was thus obvious that the 1-N-acetylation of PRM did not cause PRM resistance. Apramycin, the substrate of the known AAC(1), was not readily acetylated, suggesting that the AAC(1) of strain #8 is a new type. Two diacetylated products (1,2'-di-N-acetylPRM and 1,6"'-di-N-acetylPRM) were found in the minor spot, suggesting the existence of additional AACs.

Acetylation↗
PubMed1999

[Anterior screw fixation combined with posterior interlaminar fusion for fracture of axis: report of two cases].

Two cases of axis fracture are reported. Traffic accidents were the cause of injury in both cases. The odontoid process was dislocated anterolaterally with fracture of the lateral mass of the axis in both cases. In Case 1 good alignment of the atlas and axis could not be maintained even with a Halo-vest. The case 2 patient with spinal cord compression caused by dislocation of the axis was referred to our hospital 8 weeks after the accident. Both cases were surgically treated in a similar fashion. Because of the lateral mass fracture and lateral displacement of the atlas relative to the axis, posterior screw fixation with interlaminar fixation (Magerl) was thought to carry a risk of causing damage to the vertebral artery. Because of this, anterior screw fixation combined with posterior wiring was conducted. First, the odontoid process was fixed anteriorly by a screw because it was able to be placed back in good alignment while the patient was in the supine position. Then, the posterior C1-2 interlaminar wiring with iliac bone graft was added. Rigid fixation was obtained without any complication. Various kinds of fixation, such as posterior interlaminar wiring, odontoid screw fixation and Magerl's fixation, have been reported for the treatment of unstable axis fracture. Among them Magerl's method has been regarded as the most stable. When it is not applicable, combination of the first two methods can be an alternative way of treatment for this odontoid process fracture.

Accidents, Traffic↗
PubMed1999

[Vasculo-Behcet's disease with fatal massive hemoptysis].

A 39-year-old man was admitted to our hospital because of hemoptysis. A chest X-ray film on admission showed a patchy shadow in the left lower lung field. Computed tomography revealed nodular opacities in the left pulmonary artery. The patient had history of oral ulcers, erythema nodosum, pustular lesions, and genital ulcers. Furthermore, the needle reaction was positive. Our diagnosis was an incomplete type of Behcet's disease. A radionuclide-venography and lung-perfusion study disclosed deep-vein thrombosis. Combined therapy with prednisolone, colchicine, and indomethacin farnesil was initiated, but the patient died of massive hemoptysis. Pathological examination revealed a ruptured aneurysm in the bronchus segmentalis apacalis and thrombotic angitis in the inferior vena cava. Behcet's disease is rarely a cause of hemoptysis. However, the prevalence of hemoptysis due to pulmonary vasculitis in patients with Behcet's disease has been reported to be 5 to 10% which is not so rare. Because of the poor prognosis, we want to emphasize Behcet's disease as a cause of hemoptysis.

Adult↗
PubMed1999

[Comparison with indocyanine green angiography and immunohistochemical study of choroidal neovascular membrane in age-related macular degeneration].

PURPOSE: We classified choroidal neovascular membranes (CNMs) (48 eyes) in age-related macular degeneration (AMD) into four types using indocyanine green angiography. METHODS: Surgically extracted CNMs were examined immunohistochemically. Specimens were stained with glial fibrillary acidic protein (GFAP), von Willebrand factor, Ki-67 antigen, actin, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF), and transforming growth factor (TGF-beta 1). RESULTS: All types of CNM were positively stained with GFAP on the side opposite the retinal pigment epithelial (RPE) cells. This suggests the adherence of neurosensory retina to the CNM. Type I membranes which showed hyperfluorescence in the early and late phase of ICG angiography were significantly stained with Ki-67 antigen. CONCLUSION: These results indicate that CNMs in AMD are extracted with neurosensory retina and RPE cells during surgery. Type I membranes have a high capability for proliferation.

Choroidal Neovascularization↗