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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 397 records · Page 22Linked to original sources
PubMed1998

Amino acids and peptides. XXXI. Preparation of analogs of the laminin-related peptide YIGSR and their inhibitory effect on experimental metastasis.

Analogs of a partial sequence peptide of laminin, i.e., Tyr-Ile-Gly-Ser-Arg (YIGSR) analogs and Cys-Asp-Pro-Gly-Tyr-Ile-Gly-Ser-Arg (CDPGYIGSR) analogs, were prepared by the solid-phase method and their inhibitory effects on experimental metastasis of B16-BL6 melanoma cells were examined. YIGSR analogs in which Ile was replaced by other hydrophobic amino acids (Met, Leu, Phe) were inhibitory. Cys-containing analogs of YIGSR were also prepared, but were less active than the parent peptide, YIGSR. Among them, CYIGSR was easily oxidized to form a disulfide bond. A Cys-containing YIGSR analog cyclized through a disulfide bond, cyclo(CYIGSRC)G, was prepared. The disulfide bond formation was performed on the resin by the silyl chloride-sulfoxide method and by the iodine oxidation method. The yield of the silyl chloride-sulfoxide method was much better than that of the iodine oxidation method.

Animals↗
PubMed1998

[Biological response modifier activity of Lactococcus lactis 332].

The biological response modifier (BRM) activity of a preparation of heat killed cells of Lactococcus lactis 332 which can produce large amount of lactate in culture, was investigated in C3H/He and ICR mice. Intraperitoneal injection of Lactococcus lactis 332 caused an accumulation of neutrophils and macrophages in the peritoneal cavity of the mice, similarly to BRMs used clinically. As a parameter of the activation of macrophages, the effect of the Lactococcus lactis 332 preparation on the production of tumor necrosis factor (TNF) was examined. The Lactococcus lactis 332 preparation was revealed to have both priming and triggering activities for the production of TNF. The TNF level in the sera reached about 1000 IU/ml in mice 2 h after the triggering injection. This preparation also stimulated peritoneal macrophages to produce TNF in vitro. Intratumoral injection of the Lactococcus lactis 332 preparation regressed MM46 tumor cells in C3H/He mice. These results suggest that the Lactococcus lactis 332 preparation is a biological response modifier (BRM) with various activities on phagocytes similarly to a streptococcal antitumor agent, OK432, used clinically.

Animals↗
PubMed1998

Chemical structure of antithrombin-active Rhamnan sulfate from Monostrom nitidum.

Rhamnan sulfate was extracted with boiling water from the cell wall of Monostroma nitridum, and the resulting extract was purified by ion-exchange and size-exclusion chromatography. The polysaccharide, which is regarded as a homopolysaccharide, was 6-fold more antithrombin-active than the heparin standard. The antithrombin activity was decreased, by desulfation, although the non-active product still retained 8% of the sulfate ester. A comparative structural study of the intact rhamnan sulfate and rhamnan, its desulfated product, by periodate oxidation, Smith degradation and methylation analysis revealed the rhamnan sulfate to consist of alpha-1,3-linked L-rhamnose residues, some of which were substituted with sulfate groups mainly at position O-2. Minor amounts of internal 1,2-linked rhamnose and branched rhamnose linkages were also detected.

Carbohydrate Sequence↗
PubMed1998

Expression of the extracellular levansucrase and invertase genes from Zymomonas mobilis in Escherichia coli cells.

We investigated the expression and localization in Escherichia coli of sucZE2 and sucZE3, encoding Zymomonas mobilis extracellular levansucrase and invertase, respectively, and lacking a typical N-terminal secretion signal. Levansucrase and invertase were expressed efficiently under the lac and tac promoters in E. coli cells, and some of the levansucrase produced was localized in the periplasmic space. The sucZE2 expression was not lethal to E. coli in the presence of 5% sucrose, and led to the accumulation of levan from sucrose.

Amino Acid Sequence↗
PubMed1998

Rapid induction of lymphoid leukosis and ascites by avian leukosis virus from a lymphoid leukosis cell line.

To examine whether a lymphoid leukosis (LL) cell line releases an LL-specific avian leukosis virus (ALV) or not, two viral materials, culture fluid and a concentrated viral material from an LL-cell line, were inoculated into a total of 74 day-old chicks of line 15I in 5 experiments. Spectrum of diseases induced, their incidence and incubation periods to onset were examined. Fifteen chicks were inoculated with the culture fluid and 9 (60%) developed ascites [59-119 days post inoculation (dpi); geometric mean (GM) of dpi, GM: 89.6)], but LL was not induced in any chicks inoculated. Fifty-nine chicks were inoculated with the concentrated viral material and LL was recognized in 13 (22.0%) (27-74 dpi; GM: 48.4), ascites with LL in 11 (18.6%) (34-75 dpi; GM: 41.3), ascites alone in 21 (35.6%) (32-83 dpi; GM: 48.2), erythroblastosis in 2 (3.4%) (70-102 dpi; GM: 84.5), and other diseases in 12 (20.3%) (43-102 dpi; GM: 61.8). LL lesions were frequently observed in the liver, spleen, kidneys, bursa of Fabricius (bursa), bone marrow and gonads. Mild lymphocytic foci in some visceral organs and perivascular cuffing in the central nervous system were observed mainly in several chicks diagnosed as having complication of ascites with LL or other diseases. In addition to these lesions, atrophy of bursa and thymuses was recognized in them. No antibodies against Marek's disease virus (MDV) and reticuloendotheliosis virus were detected in 36 sera taken from the chicks inoculated with the concentrated viral material. Serotype 2 MDV was isolated from the buffy coat of some inoculated chicks. These results suggest that the properties of ALV inoculated and immunosuppression caused by inoculation with high doses of ALV are involved in rapid induction of LL and expression of pathogenicity of serotype 2 MDV released from the LL cell line and included in the viral inoculum. This is the first report describing the rapid induction of LL and ascites in chicks.

Animals↗
PubMed1998

Preoperative diagnosis with video-assisted thoracoscopy with miniaturized endoscopes in general thoracic surgery: a preliminary study.

Video-assisted thoracoscopy using a miniaturized endoscope (mini-VAT) was applied for preoperative diagnosis in general thoracic surgery. Thirty-one patients, including 27 with indeterminate pulmonary nodule and 4 with suspected pleural involvement of lung cancer or metastatic pleural tumor, underwent mini-VAT. As a pilot study, 14 of the former 27 patients underwent mini-VAT while receiving general anesthesia. As a prospective study, all the remaining 17 patients underwent mini-VAT while receiving local anesthesia. Solid scopes of three different sizes, 0.9, 1.9, or 4.0 mm diameter, were used. An artificial pneumothorax for scope introduction was produced by needle thoracentesis under atmospheric pressure. Automatic cutting needle biopsy was used for tissue sampling. In the pilot study group, mini-VAT with a 4.0-mm scope provided excellent visibility and diagnostic sensitivity of 100%. This study group showed the diagnostic sensitivity of needle biopsy for pulmonary nodule to be 100%. Hemorrhages and air leaks at biopsy sites were sealed with blood coagulation in a short time. In the prospective study group, mini-VAT with a 4.0-mm scope with the patients receiving local anesthesia provided a diagnostic sensitivity of 91% for pulmonary nodule and a diagnostic accuracy of 100% for suspected pleural involvement. Causes of failure of mini-VAT with the use of local anesthesia were cough reflex during needle biopsy and incomplete lung collapse for deeply located target in two cases. The adverse effects of the mini-VAT were paradoxical respiration in two cases in which local anesthesia was used. The patients who received only local anesthesia required no chest tube drainage. Mini-VAT is a simple, minimally invasive procedure suitable as a preoperative examination technique for histologic diagnosis, evaluation of disease progression, and selection of strategy in thoracic surgery.

Adult↗
PubMed1998

Bestatin, an aminopeptidase inhibitor, promotes follicular growth and ovulation suppressed by stress in mice.

We previously reported that the intraperitoneal and intrabursal administration of bestatin, an aminopeptidase inhibitor, enhanced follicular growth and ovulation in immature mice. In this study, we examined the effect of bestatin on follicular growth and ovulation under the conditions in which the ovarian response to gonadotropins was suppressed. Immature female mice were exposed to 72-h continuous lighting (on days 20-22 of life), or to 24-h starvation (on day 20). On days 20-22, bestatin (4 mg/ml, 100 microl) or PBS (100 microl) was administered ip. 4 times and pregnant mare serum gonadotropin (PMSG, 5 IU) and hCG (5 IU) were given on days 21 and 23, respectively. The numbers of ovulated oocytes per mice were significantly attenuated by both stresses. Bestatin significantly enhanced the numbers of ovulated oocytes under both lighting (49.5+/-7.0 vs. 28.0+/-5.5) and starvation (28.6+/-2.6 vs. 20.2+/-2.0) stresses (with vs. without bestatin, P<0.05). When follicular development was stimulated by PMSG (20 IU) on day 21, the serum estradiol concentration on day 23 was also suppressed by both stresses, but enhanced by bestatin under lighting (231.3+/-36.0 vs. 111.0+/-23.0 pg/ml) and starvation (151.9+/-8.8 vs. 90.7+/-15.4 pg/ml) stresses (with vs. without bestatin, P<0.01). Northern blot analysis revealed that the expression of P450arom-mRNA in the ovaries induced by PMSG (20 IU) was increased on day 23 by treatment with bestatin under starvation stress. These results indicated that stress inhibited the ovarian response to gonadotropins and that bestatin restored the response suppressed by stress.

Aminopeptidases↗
PubMed1998

Airway responsiveness to acetylcholine in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs in vivo and in vitro.

The characteristics of airway responsiveness to acetylcholine (ACh) in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs were clarified in vivo and in vitro. We measured the change in ventilatory mechanics in response to ACh inhalation by means of the bodyplethysmograph and the contractile responses of isolated trachea to ACh and carbachol (CCh). Further, muscarinic receptor subtypes involved these responses were identified. The basal values for ventilatory mechanics in BHS were not significantly different from those in BHR. Respiratory resistance to ACh was progressively increased in a time- and dose-dependent manner in BHS. The contractile responses of tracheal smooth muscle to ACh in BHS were significantly greater than those in BHR, but CCh-induced responses in BHS and BHR were similar. ACh- and CCh-induced contractions were mediated via M3 receptors. These results suggested that the falling-down of BHS in response to ACh inhalation was caused by the strong constriction of the airway and the reduction in ventilation. Moreover, the airway hyperresponsiveness to ACh in BHS might be partly dependent on the change in acetylcholinesterase activity.

Acetylcholine↗
PubMed1998

Histamine-induced airway contraction in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs.

Airway hyper-responsiveness is known as an important pathogenesis of asthma. In the present study, the airway responsiveness to aerosolized and injected histamine in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs was investigated. In addition, the role of the vagal reflex in histamine-induced airway contraction was evaluated by vagal blocking with atropine inhalation or bilateral vagotomy. A significantly higher bronchoconstrictive reaction, i.e., a decrease in tidal volume (VT) and an increase in respiratory resistance (Rrs), to histamine-inhalation was observed in BHS than in BHR. A noticeably lower reduction in VT was noted after atropine pretreatment for both BHS and BHR, whereas an increase in Rrs was inhibited only in BHS. The intravenous injection of histamine caused a noticeable bronchoconstrictive reaction in both BHS and BHR with a dose-dependent relationship, but no significant differences were observed and the bilateral vagotomy failed to induce any difference between the two animal groups. These results demonstrated that the airway responsiveness to histamine is considerably different in BHS from that in BHR, but the difference is largely dependent on the route of administration of histamine. The important role of the vagal reflex on the elicitation of airway contraction was elucidated in both animal groups, and it appeared that the BHS possessed relatively higher dependency on the vagal reflex mechanism than the BHR.

Administration, Inhalation↗
PubMed1998

Giant pyocele in the anterior intracranial fossa--case report.

A 43-year-old male presented with headache localized in the right forehead. Computed tomography and magnetic resonance imaging demonstrated a cystic mass in the frontal sinus, with a huge extension into the anterior cranial fossa. The mass was removed by transcranial surgery. The cyst contained pus. Histological examination of the cyst wall revealed mucocele (pyocele). Pyocele with huge intracranial extension is rare and requires combined neurosurgery and otolaryngology for optimum treatment.

Adult↗
PubMed1998

Quantitative kinetic analysis of blood vessels in the outer membranes of chronic subdural hematomas.

Dynamic biologic modeling was used to calculate the transfer rate constant for gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) and capillary permeability in the outer membrane of chronic subdural hematomas and effusions. Following intravenous Gd-DTPA injection, Gd concentrations in the subdural fluid and in timed arterial blood samples were measured by ion-coupled plasma emission spectrometry in 53 chronic subdural hematomas and 18 chronic subdural effusions. The capillary surface area in outer membrane was assessed morphometrically. Transfer rate constants for subdural hematomas and subdural effusions were 12.4 +/- 1.0 and 20.6 +/- 1.7 (x 10(-4)min-1, respectively. Capillary permeabilities for subdural hematomas and subdural effusions were 16 +/- 1.2 and 19 +/- 3.7 ml.min-1(mm2/mm3)-1, respectively. The capillary surface areas for subdural hematomas and subdural effusions were 48 +/- 3 and 77 +/- 10 mm2/mm3, respectively. The high degree of infiltration of Gd into subdural effusions reflects the high capillary surface area in the outer membrane rather than greater permeability of individual capillaries. The value of transfer rate constant was correlated inversely with the duration of the chronic subdural fluid collection. Immature outer membrane has a high transfer rate constant which allows extravasation of plasma components into the subdural space, resulting in increasing volume of the subdural effusion. Delayed magnetic resonance imaging following Gd administration may be clinically useful for estimating the age of chronic subdural fluid accumulations.

Aged↗
PubMed1998

Hemofiltration removes bradykinin generated in the priming blood in cardiopulmonary bypass during circulation.

After induction of hemofiltration for the hemic prime of a cardiopulmonary bypass, the initial drop in blood pressure disappears, and postoperative edema rarely occurs. We have suspected that bradykinin, a strong vasodilator generated through the activation of factor XII, prekallikrein, and high molecular weight kininogen was removed by ultrafiltration. We examined the changes in the activities of plasma-factor XII, prekallikrein, high molecular weight kininogen and in the levels of bradykinin in the priming blood using red cell concentrates before and after hemofiltration, and evaluated the effectiveness of hemofiltration. Ten circuits were used, and ten sets of blood samples were collected from red cell concentrates, the priming blood before hemofiltration, after hemofiltration, and the filtrate. During circulation in the circuit, factor XII, prekallikrein and high molecular weight kininogen were completely consumed and a large amount of bradykinin was generated, but it was filtered well by ultrafiltration. Factor XII, prekallikrein and high molecular weight kininogen could be activated through the dilution of red cell concentrates during the priming and contact with the circuits. Because bradykinin is the most potent vasodilator, increasing microvascular permeability and relating to several other inflammatory mediators, the removal of bradykinin generated from factor XII, prekallikrein and high molecular weight kininogen is very significant in the prevention of non-specific inflammatory reactions during and after open-heart surgery.

Bradykinin↗
PubMed1998

[An infant with lobar emphysema requiring lobectomy after ventricular septal defect closure].

A 1-month-old male infant with respiratory distress was referred to our hospital for operation of the ventricular septal defect. A chest roentgenogram demonstrated pulmonary emphysema especially in the right upper and middle lobes. At 3 months, a perimembranous ventricular septal defect was closed. But the infant could not be weaned from the ventilator. On the 21st postoperative day, a right upper and middle bilobectomy was performed. Three days later, he was weaned from the ventilator and the postoperative course was uneventful. The pathologic diagnosis revealed no bronchial cartilagenous abnormality. Infantile lobar emphysema of the right upper lobe with congenital heart disease is rather rare. We emphasize the need for lobectomy simultaneous with, secondary to, cardiac surgery in these cases.

Heart Septal Defects, Ventricular↗
PubMed1998

[Circulatory collapse during laparoscopic cholecystectomy].

A 52 year-old female without any cardiac disease underwent laparoscopic cholecystectomy. Anesthesia was induced with thiamylal and maintained with nitrous oxide and isoflurane. Epidural anesthesia was also used during surgery. When the intraabdominal insufflation was performed in reverse-trendelenburg position 15 minutes after the start of incision, the heart rate suddenly decreased from 75 to 49 bmp with a fall in blood pressure. Her hemodynamic state recovered immediately after the release of intraabdominal pressure and the administration of ephedrine with a rapid infusion of Hespander. The circulatory collapse did not occur when the second insufflation was tried carefully. The circulatory collapse was probably due to the vagal reflex. The decrease in cardiac preload during the reverse trendelenburg position and the epidural administration of local anesthetics may have caused or worsened the circulatory collapse. In anesthetic managements of laparoscopic cholecystectomy using general anesthesia with epidural anesthesia, prophylactic hydrogenation and prevention of parasympathetic domination are important to minimize the vagal reflex.

Anesthesia, Epidural↗
PubMed1998

[A case of adenoid cystic carcinoma presenting with stridor and which was treated by reversed gamma type stent placement].

A 66-year-old man was admitted to Saiseikai Suita Hospital with stridor and dyspnea. The flow-volume curve showed central airway obstruction pattern. Although a P-A chest roentogenogram was normal, chest tomogram demonstrated a tumor shadow in the lower portion of the trachea. Chest CT examination demonstrated a tumor arising from the posterior wall of the lower portion of the trachea and stenosis with wall thickening extending from the lower portion of the trachea to both main bronchi. Bronchofiberscopic examination revealed polypoid tumors obstructing the lower portion of the tracheal lumen, and biopsy was subsequently performed. On the night immediately after the bronchofiberscopic examination, the patent suddenly choked, and emergency intubation was performed. Adenoid cystic carcinoma was diagnosed on biopsy and we decided to place a spiral Z-stent. A reversed gamma-type stent placement was used. The first spiral Z-stent extended from the trachea to the right main bronchus and the second spiral Z-stent was placed in the left main bronchus through the first stent. Following the spiral Z-stent placement radiotherapy was performed. Spiral Z-stent placement resulted in dilation of the stenotic trachea and both main bronchi.

Aged↗
PubMed1998

[A case of primary squamous cell lung cancer invading the wall of the distal aortic arch and the left subclavian artery: successful surgical management using ECC with selective cerebral perfusion].

A 37-year-old male was referred to our hospital with symptoms suggesting pneumonia. The preoperative diagnosis was primary lung cancer of the left upper lobe invading the distal aortic arch (DAA) (T4, stage IIIB). Complete resection was performed with associated resection of the pneumonectomy, DAA, and left subclavian artery. Dacron graft replacement was performed using ECC with selective cerebral perfusion. Histological examination revealed squamous cell carcinoma, n1 and negative surgical margins. We expect this patient to achieve long-term survival. We conclude that ECC with selective cerebral perfusion is both safe and effective for pulmonary surgery in cases with combined resection of the DAA.

Adult↗