Search PubMedSearch

Biomedical subjects

N Maekawa

Publications and source records attributed to N Maekawa.

At least 19 recordsLinked to original sources

Induction and function of Fc epsilon RII on YT cells; possible role of ADF/thioredoxin in Fc epsilon RII expression.

The regulation of low-affinity Fc receptor for IgE (Fc epsilon RII) and the characteristics of both membrane and soluble forms of Fc epsilon RII were studied using YT cell line. We found that YT cells, a human NK like cell line, expressed Fc epsilon RII after IL-1 stimulation. Cross-linking of Fc epsilon RII on IL-1-stimulated YT cells as well as the transfectant of Fc epsilon RII-cDNA (YTSER) resulted in the up-regulation of IL-2R alpha (p55/Tac). A 59 kDa protein phosphorylated at tyrosine residues was co-immunoprecipitated with Fc epsilon RII from YTSER lysate using H107 anti-Fc epsilon RII mAb. YTSER not only expressed Fc epsilon RII on their surface but also secreted soluble form of Fc epsilon RII (sFc epsilon RII/sCD23; IgE binding factor). Affinity purification revealed that sFc epsilon RII released from YTSER is heterogeneous and consisted of several proteins differing in molecular weight. Both EBV+ B cells and HTLV-1+ T cells are high producers of ATL derived factor (ADF)/thioredoxin (TRX) and express Fc epsilon RII and IL-2R alpha respectively. To clarify the mechanism of Fc epsilon RII and IL-2R alpha induction by ADF/TRX, we examined the effect of ADF/TRX on the bindability of nuclear factor kappa B (NF-kappa B), which is known to regulate IL-2R alpha gene expression. In the gel shift assay, ADF/TRX was shown to enhance the bindability of NF-kappa B to its responsive element.

Base Sequence

Effect of verapamil on the cardiovascular responses to tracheal intubation.

We have studied the efficacy of verapamil in attenuating the cardiovascular responses to tracheal intubation in three groups of ASA grade I patients given verapamil 0.05 mg kg-1 or 0.1 mg kg-1 or saline 45 s before the start of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. In patients who received saline, there was a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. The increases were significantly less in verapamil-treated patients compared with those in the control group, although verapamil failed to prevent tachycardia caused by laryngoscopy and intubation.

Adult

Effects of butylated hydroxyanisole on ornithine decarboxylase activity induced by ultraviolet-B and PUVA in mouse skin.

The effects of butylated hydroxyanisole (BHA), a representative phenolic antioxidant, on the activity of ornithine decarboxylase (ODC, an indicator of tumor promotion and epidermal hyperproliferation) induced by ultraviolet-B (UVB) or PUVA in mouse skin were investigated. By topical application of BHA (55 mumol), PUVA-induced ODC activity was suppressed by about 60% at both 12 h and 24 h after treatment. In contrast, BHA failed to suppress UVB-induced ODC activity in mouse skin. These results suggest that the induction of ODC activity by UVB or PUVA is mediated by different pathways.

Animals

Perioperative complement activation in neonates under halothane or fentanyl anaesthesia.

We investigated perioperative changes in complement activation in 18 neonates undergoing elective abdominal surgery with or without thoracotomy by measuring plasma concentrations of C3a and C5a, and leucocyte counts in peripheral blood. The 18 neonates, ranging in age from 1 to 17 days, were randomly divided into two groups according to type of anaesthetic procedures; the "halothane group" consisted of nine neonates in whom general anaesthesia was maintained with halothane and nitrous oxide (N2O) in oxygen, while the "fentanyl group" consisted of nine neonates in whom general anaesthesia was maintained with fentanyl and N2O in oxygen. Plasma C3a and C5a concentrations were higher in the fentanyl group than in the halothane group during the perioperative period. We have demonstrated that abdominal surgical trauma caused complement activation even in neonates undergoing the fentanyl rather than the halothane anaesthesia. Further studies are required to elucidate the precise mechanisms and the clinical implication of perioperative complement activation in neonates.

Abdomen

Effects of mexiletine on the haemodynamic responses to tracheal intubation.

The efficacy of intravenous mexiletine in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation was studied in 30 normotensive patients undergoing elective surgery. The patients were randomly allocated to one of three treatment groups: saline (n = 10); 2 mg/kg mexiletine (n = 10); and 3 mg/kg mexiletine (n = 10). The placebo/mexiletine was administered immediately before induction of anaesthesia using 5 mg/kg thiopentone and tracheal intubation was facilitated with 0.2 mg/kg vecuronium; laryngoscopy lasting 30 s was attempted 2 min after induction of anaesthesia. All groups showed a significant (P less than 0.05) increase in mean arterial pressure and heart rate associated with tracheal intubation. The increase in mean arterial pressure was significantly (P less than 0.05) smaller in patients receiving 3 mg/kg mexiletine compared with those receiving either saline or 2 mg/kg mexiletine. There was no significant attenuation in heart rate in either of the mexiletine treatment groups compared with the saline group. It is concluded that 3 mg/kg mexiletine given intravenously provides a simple and effective method for attenuating the pressor response to laryngoscopy and tracheal intubation.

Adult

[Usefulness of renal CT scan for analysis of nutcracker phenomenon].

Among 24 patients with confirmed left renal bleeding, 11 were diagnosed of having nutcracker phenomenon (NP) on the basis of the results of renal venography and pull-back pressure from the left renal vein to the inferior vena cava. Renal CT scan was performed for these 11 patients, and its usefulness as a means of diagnostic analysis was studied. The following results were obtained. 1. The left kidney was scanned at 5-mm intervals. The mean distance between the anterior surface of the abdominal aorta (Ao) and the posterior surface of the superior mesenteric artery (SMA) was 4.5 +/- 0.6 mm in the NP group, while it was 13.9 +/- 6.4 mm in the control group (p < 0.01). 2. Regarding the morphology of the left renal vein (LRV), tapering dilatation, i.e., funnel-like dilatation, from the left side of Ao was seen in the NP group. In the control group, the left renal vein showed a club-like shape continuing to the inferior vena cava and showed no dilatation. 3. Vascular structures indicative of collateral vessels were observed around the LRV in the NP group. If renal CT scan is performed at 5-mm intervals, the following CT finding are thought to be indicative of the nutcracker phenomenon; (1) a distance of 5 mm or less between Ao and SMA and (2) tapered dilatation of the LRV. This study suggests that renal CT scan is useful for diagnostic analysis of the nutcracker phenomenon.

Adolescent

Adult T-cell leukaemia-derived factor/thioredoxin expression on the HTLV-I transformed T-cell lines: heterogeneous expression in ALT-2 cells.

Adult T-cell leukaemia (ATL)-derived factor (ADF), originally described as an inducer of interleukin-2 receptor-alpha (IL-2R alpha/Tac), has homology with the co-enzyme thioredoxin which is involved in many dithiol-dependent reducing processes. Using antibody against the C-terminal synthetic polypeptide of ADF and RNA probe of ADF, we examined the expression of ADF in various cell lines by immunofluorescence, immunohistochemical staining, Western blotting and in situ hybridization. ADF was intensely expressed on HTLV-I+ T-cell lines as compared with HTLV-I- T-cell lines. While the Epstein-Barr virus (EBV)+ B-lymphoblastoid cell lines were intensely positive for ADF, Burkitt-derived B cell line Jijoye with defective EBV was negative for ADF. Electron microscopic and photomicroscopic analysis of HTLV-I+ ATL-2 cells showed that ADF was localized on both the cell membrane and cytosol. In ATL-2 cells, a marked heterogeneity of ADF expression was observed. In in situ hybridization, heterogeneity of ADF messenger RNA (mRNA) expression was also demonstrated, indicating that ADF expression was regulated in the transcriptional level.

Blotting, Western

Induction of Fc epsilon RII/CD23 on PHA-activated human peripheral blood T lymphocytes and association of fyn tyrosine kinase with Fc epsilon RII/CD23.

Despite the evidence for the expression of Fc epsilon RII/CD23, a glycoprotein that is a low-affinity Fc receptor for IgE, obtained on T cell lines and some pathological T cells, that of Fc epsilon RII/CD23 on normal human T cells is still unclear. We studied the emergence of T cells bearing Fc epsilon RII/CD23 in short-term culture of normal human peripheral blood mononuclear cells stimulated with 15 microliters/ml phytohemagglutinin (PHA). Using two-dimension flow cytometry, more than 10% of Fc epsilon RII/CD23(+) cells were shown to co-express CD3 antigen. Both CD4(+) and CD8(+) T cells expressed Fc epsilon RII/CD23. The expression of mRNA for Fc epsilon RII/CD23 on PHA and IL-4 stimulated PBMC was demonstrated by northern blotting and in-situ hybridization. The mechanism of signal transduction through Fc epsilon RII/CD23 was dissected by transfection of cDNA coding for Fc epsilon RII to the human natural killer-like cell line YT, activation of which was easily detected by the induction of interleukin-2 receptor/p55 (Tac). Cross-linking of Fc epsilon RII/CD23 with H107 anti-Fc epsilon RII monoclonal antibody enhanced IL-2R/p55 expression on YT cells transfected with Fc epsilon RII cDNA (YTSER). A possible involvement of protein-tyrosine kinase in the Fc epsilon RII-mediated signal transduction was studied using YTSER. Fc epsilon RII was physically associated with an src-family tyrosine kinase p59fyn and not with p56lck, which was also found in YT cells. Recently it was reported that p59fyn was associated with T-cell antigen receptor. Our results collectively suggest the multiple function of p59fyn which may be implicated in the Fc epsilon RII-mediated activation signal in YT cells.

Blotting, Northern

[Coronary artery spasm during coronary artery bypass surgery].

We report two cases of coronary artery spasm during coronary artery bypass surgery. As one of the complications during cardiac surgeries, coronary vasoconstriction occurs mainly after coming off cardiopulmonary bypass. The factors responsible for the spasm include high endogenous catecholamine levels due to inadequate anesthesia and hypothermia, exogenous catecholamines for circulatory support, various chemical mediators and combination of these factors. Coronary artery spasm was suspected strongly because of sudden ischemic change in electrocardiography and simultaneous aggravation of circulatory parameters, which improved immediately after direct injection of coronary vasodilators into vein graft. This method, popular in coronary angiography and catheterization, is effective for release of coronary-artery spasm observed particularly after cardiopulmonary bypass. Then mechanical circulatory assist is readily available to treat possible systemic side effect of the vasodilators.

Coronary Artery Bypass

[Clinical study on cough variant asthma].

Chronic cough may be the sole presenting manifestation of bronchial asthma (reference 3; Corrao et al, 1979), and "cough variant asthma (CVA)" has been used to categorize such patients. In order to clarify the clinical picture of CVA, we evaluated the clinical history, laboratory data, sputum cytology and pulmonary function in 14 subjects (5 males and 9 females, aged 14 to 65 years) compatible with the following diagnostic criteria: (1) chronic cough persistent for more than 8 weeks, (2) no wheeze nor dyspnea, (3) no rales, (4) no past history of asthma, (5) bronchial hyperreactivity to methacholine proven by Takishima's method (reference 13), (6) effectiveness of bronchodilators against cough, (7) normal chest X-ray film, (8) afebrile and negative CRP, (9) absence of sinusitis and postnasal drip, or if present, they are proved not to be responsible for the cough, and (10) no other causes of cough such as heart disease, prescription of ACE inhibitors, current smoking. The results were as follows. 1) Many of the subjects were atopic, with positive skin tests to one or more common allergens in 10 subjects, elevated serum IgE in 4 subjects, and past history and family history of atopy in 4 and 7 subjects, respectively. 2) Respiratory infection preceded the onset of CVA in 3 subjects. 3) Cough was generally nocturnal, but 2 subjects coughed only in the daytime. 4) FEV1.0% was decreased (less than 70%) in only 2 subjects, whereas V25 was decreased (less than 80% of predicted value) in 11 out of 12 evaluable subjects, which suggested peripheral airway obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

[A case of dermatomyositis associated with thymic abnormalities].

A case of dermatomyositis (DM) associated with thymic cyst with lymphoid follicle formations has been reported. A 57-year-old man developed polyarthralgia, muscle weakness, heliotrope rash and Gottron's sign. Laboratory findings showed elevated values of creatine-phosphokinase, aldolase and transaminase. He was diagnosed as DM and was treated with prednisolone 50 mg/day. Muscle weakness was improved immediately, although rash persisted unchangeably. He was examined for coexistence of malignant tumor which had been reported frequently as associated with DM. Enlargement of thymus was found by computer tomography and then thymectomy was performed. In his thymus, lymphoid follicle formations, which are as often encountered in other autoimmune diseases, were found. So far, the beneficial effect of thymectomy on the improvement of immunological abnormalities not only in patients with myasthenia gravis but also in patients with other autoimmune diseases has been recognized. In this case, intractable rash in DM improved after thymectomy. Further study needs to clarify the relationships between DM and thymic abnormalities.

Dermatomyositis

[A resuscitated case of sleep apnea syndrome with cardiac arrest].

A 71-year-old man was noted to habitually snore loudly at night and have a predisposition to somnolence during the daytime. While dozing during the day, he developed cardiac arrest at the time when snoring stopped, and was resuscitated. By means of a respiration monitor, he was diagnosed as having sleep apnea syndrome (SAS) with a combination of obstructive, central, and mixed type. However, neither respiratory insufficiency nor cardiac insufficiency was observed, and there were no abnormal findings on laboratory tests and bronchoscopy. SAS complicated by cardiac arrest is usually seen in cases with concomitant symptoms such as excessive obesity, hypertension, arrhythmia, right heart insufficiency, secondary polycythemia, or mental disorder. The present case abruptly developed cardiac arrest in the absence of such symptoms. This case therefore suggests the importance of screening tests using a respiration monitor during sleep in subjects who have a loud snore or a predisposition to somnolence during the daytime. Although treatment with UPPP alone had no noticeable effect, UPPP treatment combined with sleeping in the lateral position was effective in the present case. The efficacy rate of UPPP has been reported to be 50 to 60%. The early establishment of a method for precise evaluation of the site of obstruction as well as criteria for appropriate application of UPPP are urgently required.

Aged

[Clinical study on responses of the upper esophageal sphincter after subtotal esophagectomy for esophageal cancer].

Responses of the upper esophageal sphincter (UES) to distention of the esophageal wall by use of a balloon catheter were measured in 30 patients after subtotal esophagectomy for esophageal cancer and 33 volunteers with unrelated disorders (control group). Patients were divided into extended dissection group and non-extended dissection group according to the width of lymph node dissection, or palsy group and non-palsy group according to recurrent-laryngeal nerve palsy. The resting upper esophageal sphincter pressure (UESP) and the upper esophageal sphincter contraction (UESC) following UES induced by swallowing were measured after esophageal distention. Neither of UESP nor UESC without distention was significantly different among each group. But those of the extended dissection group and palsy group after esophageal distention were significantly lower values than those of control group. These findings suggest that responses of the UES to distention of esophageal wall are decreased, thus protection against aspiration is probably decreased.

Adult

Induction of Fc epsilon RII/CD23 on phytohemagglutinin-activated human peripheral blood T lymphocytes. I. Enhancement by IL-2 and IL-4.

Despite evidence for the expression of low affinity Fc receptor for IgE (Fc epsilon RII)/CD23 in T cell lines and pathologic T cells, Fc epsilon RII/CD23 in normal human T cells is still unclear. We studied the expression of Fc epsilon RII/CD23 on T cells in short-term culture of normal human PBMC stimulated with 15 micrograms/ml PHA. PHA stimulation also resulted in the release of soluble Fc epsilon RII/CD23 (IgE binding factor). Using two-dimensional flow cytometry, more than 10% of the Fc epsilon RII/CD23+ cells were found to co-express CD3 Ag. Both CD4+ and CD8+ T cells expressed Fc epsilon RII/CD23. The induction of Fc epsilon RII/CD23 on PHA-activated T cells was enhanced by IL-2 as well as IL-4. Both IL-2 and IL-4 also augmented PHA-induced production of soluble Fc epsilon RII/CD23. The enhanced expression of Fc epsilon RII/CD23 on T cells by both lymphokines was suppressed by rabbit anti-IL-4 antiserum, suggesting the involvement of an IL-4-dependent process even in the IL-2-dependent Fc epsilon RII/CD23 expression on T cells. The expression of mRNA for Fc epsilon RII/CD23 on PHA and IL-4-stimulated PBMC was examined by Northern blot analysis. Fc epsilon RII/CD23 mRNA was detected in RNA prepared from the T cell fraction depleted of B cells and macrophages (Fc epsilon RII+CD3+ = 6.2%, Fc epsilon RII+CD3- = 0.8%). The expression of the mRNA for Fc epsilon RII/CD23 on CD3+ T cells was also confirmed by in situ hybridization with Fc epsilon RII/CD23 cDNA combined with CD3 rosette formation at the single cell level.

Antibodies, Monoclonal