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Biomedical subjects

F Suzuki

Publications and source records attributed to F Suzuki.

At least 109 records · Page 6Linked to original sources
PubMed1999

Intermittent bundle branch blocks in a patient with uncommon-type atrioventricular nodal reentrant tachycardia and enhanced atrioventricular nodal conduction.

We report on a patient with uncommon-type atrioventricular (AV) nodal reentrant tachycardia with a short tachycardia cycle length (235-270 ms), in whom transient wide QRS tachycardia with both left bundle branch block and right bundle branch block aberrancy were followed by narrow QRS complexes. In addition, His-ventricular (H-V) block and a sudden prolongation of the H-V interval occurred during the tachycardia. As the determinant of these unusual findings, the possibility that the anterograde limb of the reentry circuit has an enhanced AV nodal conduction property is discussed, as is the clinical significance of this type of tachycardia.

Adult↗
PubMed1999

Some interactions of L-DOPA and its related compounds with glutamate receptors.

L-DOPA is probably a transmitter and/or modulator in the central nervous system (1). L-DOPA methyl ester (DOPA ME) is a competitive L-DOPA antagonist. However, it remains to be clarified whether there exist L-DOPAergic receptors. In Xenopus laevis oocytes injected with rat brain poly(A)+ RNA, L-DOPA induced small inward currents with ED50 of 2.2 mM at a holding potential of -70 mV. The currents were abolished by kynurenic acid or CNQX. Similar L-DOPA-currents were seen in oocytes co-injected with AMPA receptors, GluRs1,2,3 and 4. In brain membrane preparations, L-DOPA inhibited specific binding of [3H]-AMPA with IC50 of 260 microM. This inhibition was not modified by 200 microM ascorbic acid, an antioxidant. L-DOPA did not inhibit binding of [3H]-ligands of MK-801, kainate, DCKA and CGP39653. DOPA ME and L-DOPA cyclohexyl ester, a novel, potent and competitive antagonist (2), inhibited specific binding of [3H]-MK-801 with respective IC50 of 1 and 0.68 mM, but elicited no effect on that of the other [3H]-ligands. With low affinities, L-DOPA acts on AMPA receptors, while competitive antagonists act on NMDA ion channel domain. L-DOPAergic agonist and antagonist may not interact on ionotropic glutamate receptors. DOPA ME-sensitive L-DOPA recognition sites (1) seem to differ from glutamate receptors.

2-Amino-5-phosphonovalerate↗
PubMed1999

The contribution of inducible nitric oxide and cytomegalovirus to the stability of complex carotid plaque.

BACKGROUND: Although the association between inflammation and atherosclerosis is well established, the biologic events that trigger the local inflammatory response within plaque are not fully understood. Cytotoxic free radicals and infectious agents, both of which are associated with an inflammatory response, have previously been implicated in the initiation and progression of atherosclerosis. In this study, we analyzed carotid plaque for evidence of oxidative vascular injury by determining the presence and distribution of inducible nitric oxide synthase (iNOS) expression and nitrotyrosine formation and for evidence of infection with cytomegalovirus. METHODS: Carotid plaque from 51 patients who underwent endarterectomy for either primary (n = 37) or recurrent (n = 14) stenosis were examined histologically (hematoxylin-eosin staining and Masson's trichrome staining) and with immunohistochemistry with specific antibodies to alpha-smooth muscle actin, macrophages (CD68), T-lymphocytes (CD3), and T-cell activation (human leukocyte antigen-DR). Twenty-eight specimens from patients with primary (n = 15) and recurrent (n = 13) stenosis were examined for the presence of iNOS and nitrotyrosine with immunohistochemistry and in situ hybridization (iNOS). Twenty-three additional specimens (22 primary, and 1 recurrent) were analyzed with antibodies to p53, cytomegalovirus, and the polymerase chain reaction (cytomegalovirus, n = 8). RESULTS: Primary atherosclerotic lesions were either complex heterogenous cellular plaques (n = 29) or relatively acellular fibrous plaques (n = 8). Ten of 14 recurrent plaques were either complex or fibrous lesions, and the remaining four were typical of myointimal thickening. CD68-positive staining cells were detected in all specimens regardless of their structural morphology. CD3-positive cells were interspersed between macrophages in all heterogeneous cellular plaques and only infrequently noted in fibrous plaques. iNOS and nitrotyrosine immunoreactivity were detected in macrophages and smooth muscle cells in all complex and fibrous plaques and in two of four myointimal plaques. The presence of iNOS and nitrotyrosine in plaque correlated with the existence of symptoms in 80% of primary and 62% of recurrent lesions. Cytomegalovirus was detected in only two of 23 carotid specimens (9%). CONCLUSION: The association between ischemic cerebrovascular symptoms and iNOS and nitrotyrosine immunoreactivity in complex primary and recurrent carotid plaque and the infrequent occurrence of cytomegalovirus in primary carotid lesions suggests that ongoing free radical oxidative damage rather than viral infection may contribute to plaque instability in patients with complex and fibrous carotid plaques.

Aged↗
PubMed1999

Evaluation of alpha1-adrenoceptors in the rabbit iris: pharmacological characterization and expression of mRNA.

Subtypes of alpha1-adrenoceptor in rabbit iris have been examined in functional, binding and molecular biological experiments. In functional studies, exogenous and endogenous noradrenaline produced contractions of the iris dilator muscle. The contractile responses to noradrenaline were competitively antagonized by a range of alpha1-adrenoceptor antagonists (pA2 values): prazosin (8.1), WB4101 (8.2), BMY7378 (5.9), YM617 (9.5), JTH-601 (8.8), HV723 (7.8) and KMD-3213 (9.8). The same order of inhibitory potency was seen in the adrenergic responses to electrical stimulation. This affinity profile corresponds well to that of the putative alpha1L-adrenoceptor, which has been proposed in lower urinary tract tissues. In binding studies on rabbit iris membrane however, prazosin, KMD-3213 and WB4101 displayed high affinity (pKd or pKi: 9.6, 10.3, 9.6, respectively), and BMY7378 displayed low affinity (pKi: 6.9). These results show that the binding sites typically correspond to alpha1A-adrenoceptor subtype in character, and we could not detect the significant amount of alpha1L-adrenoceptor subtype. The expression of the three distinct mRNAs that encode proteins of alpha1a-, alpha1b- and alpha1d-adrenoceptors was studied using reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR demonstrated the strongest expression of the alpha1a-adrenoceptor, weak expression of the alpha1b-adrenoceptor and undetectable expression of the alpha1d-adrenoceptor. The present study suggests that alpha1A-adrenoceptor is a major subtype detectable in binding and RT-PCR studies in rabbit iris, but that the adrenergic contractions of iris dilator muscle are mediated via activation of alpha1-adrenoceptor subtype having low affinity for prazosin and WB4101.

Adrenergic alpha-Agonists↗
PubMed1999

Effects of glycyrrhizin, an active component of licorice roots, on Candida albicans infection in thermally injured mice.

Due to the generation of burn-associated CD8+ CD11b+ TCR gamma/delta+ type 2 T cells (burn-associated type 2 T cells), the susceptibility of thermally injured mice to infection with C. albicans has been shown to be increased by up to 50-fold when compared with normal mice. Glycyrrhizin (GR), an active component of licorice roots, reduced the susceptibility of thermally injured mice to C. albicans infection to levels observed in normal mice. Thermally injured mice inoculated with CD4+ T cells from GR-treated mice were also resistant to C. albicans infection. The following demonstrated that susceptibility to fungal infection was similar in thermally injured mice and normal mice inoculated with T6S cells (a clone of burn-associated type 2 T cells). This susceptibility of T6S mice (normal mice inoculated with T6S cells) was reversible by (i) administration of GR, (ii) inoculation of CD4+ T cells from GR-treated mice, and (iii) injection of a mixture of MoAbs targeted against type 2 cytokines (IL-4 and IL-10). After stimulation with anti-CD3 MoAb, splenic T cells from thermally injured and T6S mice, treated with GR or inoculated with CD4+ T cells from GR-treated mice, did not have type 2 cytokines in culture supernatants. They were present in splenic T cell cultures from thermally injured and T6S mice that were treated with saline or inoculated with naive T cells. These results suggest that GR, by inducing CD4+ T cells which suppress type 2 cytokines produced by burn-associated type 2 T cells, improves the resistance of thermally injured mice to C. albicans. An anti-type 2 T cell action of the CD4+ T cells derived from GR-treated mice was previously described.

Amphotericin B↗
PubMed1999

Intra-abdominal angiosarcomatosis after radiotherapy.

BACKGROUND: We report a case of a 61-year-old Japanese woman who developed intra-abdominal angiosarcomatosis 20 years after receiving radiotherapy for squamous cell carcinoma of the cervix. METHODS AND RESULTS: The surgically resected portion of the ileum showed diffuse proliferating angiosarcoma, with irregular channels lined by atypical vascular endothelial cells. Immunohistochemical studies showed that the tumour cells were positive for Factor VIII-related antigen and ulex europaeus agglutinin 1. At autopsy, the tumour had disseminated to the peritoneum and invaded into the right thoracic cavity. CONCLUSIONS: These findings were compatible with radiation-induced angiosarcomatosis.

Carcinoma, Squamous Cell↗
PubMed1999

Serum thrombopoietin levels in patients with chronic hepatitis and liver cirrhosis.

OBJECTIVE: Thrombocytopenia is a common manifestation of cirrhosis. The aim of this study was to examine the relationship between serum thrombopoietin concentrations, circulating platelet levels, and the stage of hepatic fibrosis in patients with chronic viral hepatitis. METHODS: The study included 48 patients with chronic viral hepatitis (14 with stage 1 fibrosis; five with stage 2 fibrosis; three with stage 3 fibrosis; 26 with cirrhosis) and 30 healthy volunteers. Serum thrombopoietin levels were measured using an enzyme-linked immunosorbent assay. Spleen size, platelet counts, and prothrombin time were measured. RESULTS: Thrombopoietin levels of patients with fibrosis stage 1 (2.50 +/- 1.60 fmol/ml) or stage 2 (1.89 +/- 0.65) were significantly higher than those in patients with cirrhosis (1.21 +/- 0.55) or healthy volunteers (1.26 +/- 0.74). Mean platelet counts of patients with cirrhosis (8.0 +/- 4.6 x 10(4)/microl) were significantly lower than those with fibrosis stage 1 (18.6 +/- 3.9) or stage 2 (16.0 +/- 5.8), or healthy volunteers (24.5 +/- 7.3). Patients with cirrhosis had larger spleens (30.9 +/- 18.4 cm2) than those with fibrosis stage 1 (18.2 +/- 6.4). Platelet counts showed a significant inverse relationship to spleen size (p = -0.51, p < 0.0005) and a significant positive relationship with thrombopoietin levels (p = 0.34, p < 0.02). Thrombopoietin levels were significantly correlated to prothrombin time (p = 0.45, p < 0.005). CONCLUSIONS: Serum thrombopoietin levels are elevated in patients with an early stage of chronic viral hepatitis. As the disease progresses from mild fibrosis to cirrhosis, decreased production of thrombopoietin may contribute to the further development of thrombocytopenia in cirrhosis.

Adult↗
PubMed1999

Antiviral effect of gingyo-san, a traditional Chinese herbal medicine, on influenza A2 virus infection in mice.

Gingyo-san is a crude drug containing extracts from 7 medicinal plants and fermented soybeans in a specific ratio. It has been used clinically in China as a therapeutic agent for the common cold. In the present study, we examined the antiviral effect of this agent on influenza virus infection in mice. Gingyo-san and its components were administered orally to mice 1 day before, then 1 and 4 days after the inhalation of a mouse-adopted strain of influenza A2 (H2N2) virus. After infection with a 10 LD50 of the virus, 100% of mice treated with 10 mg/kg of the agent survived as compared with a 0% survival of control mice treated with saline. Also, the mean survival days were increased and consolidation scores were decreased in treated mice as compared with those of control mice. Two components contained in the agent, extracts from Glycyrrhizae radix and Arctii fructus, expressed antiviral activities in mice infected with influenza virus. However, in vitro growth of influenza virus in MDCK cells or viability of the virus was not affected by these extracts or Gingyo-san. From these results Gingyo-san was shown to be an antiviral agent in mice infected with a lethal amount of a mouse-adopted strain of influenza A2 virus.

Animals↗
PubMed1999

The response of the slow atrioventricular nodal pathway to temperature.

The present study attempted to determine the lowest temperature at which the slow atrioventricular nodal pathway responds to heating and the temperature necessary for successful ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT). The study group comprised 23 consecutive patients (14 women, 9 men) with symptomatic AVNRT. Radiofrequency current was delivered at the slow pathway potential recording site using a HAT 200S catheter ablation system. Successful radiofrequency ablation of the slow pathway was achieved in all 23 patients. Junctional beats, suggesting the response of the slow pathway to temperature, were detected in 62 of the total 136 applications. The temperature measured at the first junctional beat was 45.4+/-4.2 degrees C. The maximum temperature required for the successful ablation of AVNRT ranged from 45 to 88 degrees C. There were no complications except for 1 patient with transient atrioventricular (AV) block. There were no recurrences of AVNRT during follow-up. The lowest temperature at which the slow pathway was responsive to heat was quite similar to that for accessory pathways or the AV junction. However, the temperature required for the successful ablation of AVNRT differed markedly among the patients.

Adult↗
PubMed1999

[Two-phase responses of acid expulsion triggered by alpha-1a adrenoceptor in CHO cell].

Using microphysiometer, we have investigated acid expulsion from CHO cells expressing human alpha-1a adrenoceptor. Time course of extracellular acidification rate after noradrenaline stimulation had two phases; one with a peak within 10 s reached several folds of base rate, and another increased gradually to two folds of base rate and reached plateau around two min. Both phases showed concentration-dependent increase of acidification rates in response to noradrenaline but had distinct pEC50 values; 6.0 for rapid phase and 6.6 for late phase. Amiloride and its analogs inhibited both phases entirely, suggesting that Na/H exchanger mainly mediated these acid expulsion responses. Elimination of Ca by BAPTA/EGTA treatment resulted in extensive reductions of the rapid phase response but small decrease of the late phase response. Several Ca channel blockers, Ni and LOE908 also suppressed the rapid phase while nifedipine, verapamil, SKF96365 and omega-conotoxin GIVA did not. Repeated stimulation with noradrenaline enhanced inhibitory effect of blockers. These results indicate that Ca is one of the elements in the rapid phase but not in the late phase of acid expulsion from CHO cells in response to alpha-1 adrenoceptor stimulation and suggest that Ca from both intracellular storage and some type of Ca channel dominantly participates in the rapid phase.

Acetamides↗
PubMed1999

Tyrosine-83 of human renin contributes to biphasic pH dependence of the renin-angiotensinogen reaction.

The pH dependence of the reaction of human renin with sheep angiotensinogen had a couple of peaks at pH 6.5 and 8.7. The renin activity at pH 8.7 was 1.4 times higher than that at pH 6.5. After the substitutions of Phe, Ala, and His for Tyr83 of human renin, the peak at pH 6.5 could be observed but the peak at pH 8.7 disappeared. At pH 6.5, these substitutions reduced the kcat of human renin to 11.1, 1.31, and 3.49% of that of wild-type renin, respectively, while their Km remained at similar levels to that of the wild type. These results indicate that Tyr83 of human renin contributes to the renin-angiotensinogen reaction at both pHs and it is essential for the catalytic reaction particularly at the basic pH.

Angiotensinogen↗
PubMed1999

Non-proteolytic activation of human prorenin by anti-prorenin prosegment (pf#1: 1P-15P) antiserum.

Recombinant human prorenin was activated by incubation with anti-prorenin prosegment (L1PPTDTTTFKRIFLKR15P) antiserum at 4 degrees C. This activation was dependent on the concentration of the antiserum and incubation time. After the activation no molecular weight alteration of prorenin was observed by immunoblotting analysis. A peptide of L1PPTDTTTF8P as well as L1PPTDTTTFKRIFLKR15P potently interfered with the activation. Most of the activated prorenin bound to Protein A Sepharose CL 4B. The Km and Vmax values of the activated prorenin were 0.2 microM and 23.7 micrograms Ang I/ml/h, respectively, which were similar in level to those of mature renin obtained by trypsinization.

Amino Acid Sequence↗
PubMed1999

Slow-fast form of atrioventricular nodal reentrant tachycardia with eccentric retrograde left-sided activation.

A case of atypical AV nodal reentrant tachycardia (AVNRT) with eccentric retrograde left-sided activation, masquerading as tachycardia using a left-sided accessory pathway, is reported. Initially, it appeared that the tachycardia was a typical slow-fast form of AVNRT. The earliest retrograde activation, however, was registered at a site approximately 3 cm from the coronary sinus orifice (left atrial free wall), indicating atypical AVNRT. Atrial tachycardia and orthodromic AV reciprocating tachycardia using an accessory AV pathway were excluded. Slow pathway ablation at the posteroseptal right atrium eliminated the tachycardia. It was suggested that the anterograde limb of the tachycardia circuit was a slow AV nodal pathway with typical posteroseptal location, whereas the retrograde limb was a long atrionodal pathway connecting the compact AV node and the left atrial free wall near the mid-coronary sinus.

Atrioventricular Node↗
PubMed1999

[Biological properties of T6S cells, a clone of burn-associated type 2 T cells].

A clone of type 2 T cells (T 6 S cell) was established from burn-associated CD 8+ CD 11 b+ TCR gamma/delta + type 2 T cells, and their biological properties were examined. After stimulation by anti-CD 3 monoclonal antibody (mAb), T 6 S cells produced IL-4 and IL-10 into their culture fluids. However, IFN-gamma and IL-2 were not demonstrated in the culture fluids of T 6 S cells stimulated with the mAb. The susceptibility of thermally injured mice to infection with herpes simplex virus type 1 (HSV-1) or Candida albicans (C. albicans) has been shown to be approximately 50 (C. albicans) to 100 (HSV-1) times greater than that of normal mice. As compared with the resistance of thermally injured mice to these pathogens, mice inoculated with 1 x 10(6) cells/mouse of T 6 S cells (designated as T 6 S-mice) showed the same susceptibility to the infections. When T 6 S-mice treated with a mixture of monoclonal antibodies (mAbs) directed against IL-4 and IL-10 were infected with a lethal dose of HSV-1 or C. albicans, their resistance to these pathogens was restored to levels found in normal mice. From the experiments using T 6 S-mice, it is suggest that type 2 T cells or their cytokine products (IL-4 and IL-10) may play an important role on the impaired resistance of thermally injured mice to certain opportunistic pathogens. T 6 S cell may be a useful tool to study opportunistic infections in hosts bearing type 2 T cells.

Animals↗
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

[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

[Relation between human papilloma virus DNA and expressions of p53 and p21 proteins in cervical lesions].

Oncogenic types of human papilloma virus (HPV) are known to be closely associated with cervical carcinoma. On the other hand, the oncogenic process is associated with various abnormalities in the mechanisms of cellular regulation. In this study, we detected the expressions of p53 and p21 proteins in cervical lesions by immunohistochemical techniques, and examined the relationship with HPV infection as well as the clinical usefulness of the results. Cervical biopsy specimens from 107 cases of cervical lesions were studied. HPV-DNA was detected by the hybrid capture method using probe A for low oncogenic types and probe B for high oncogenic types. Anti p21, anti-p53 antibodies were used to perform immunostaining. Point mutation in the p53 gene was analyzed by the DGGE method. High oncogenic HPV types were detected at high frequencies in CIN and SCC. In lesions associated with high oncogenic HPV, p53 protein was detected in 33.4% of the lesions and p21 protein in 36.3%. The p53 gene was analyzed in all cases, and point mutation was not detected. No relation was detected between HPV infection and p53/p21 protein expression. Since mutation was not found in the p53 gene, the p53 protein expressed was considered to be wild-type, which is suspected to play a role in inhibiting disease progression in some cases.

DNA, Viral↗