Biomedical subjects

H Kubo

Publications and source records attributed to H Kubo.

At least 73 records · Page 4Linked to original sources

PubMed2000

Novel potassium channel opener prodrugs with a slow onset and prolonged duration of action.

(-)-(3S,4R,1'R,6'S)-4-(4-Benzyl-5-oxo-3,4-diazabicyclo[4.1.0]hept-2-en-2 -yloxy)-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-6-carbo nitrile and its derivatives with a modified benzyl group were synthesized with the objective of discovering novel ATP-sensitive potassium channel openers (PCOs) with a slow onset of action and a reduced tendency to induce tachycardia. Among the compounds synthesized, 4-(2-chlorobenzyl) derivative 5bB had potent hypotensive activity in spontaneously hypertensive rats (SHRs). In addition, compound 5bB showed the desired pharmacological profile with a slow onset and long duration of action and induction of only mild tachycardia. Compound 5bB was found to be quantitatively metabolized in rats to give active des-2-chlorobenzyl derivative 6B. These results suggest that the incorporation of an N-benzyl group is a useful method for the preparation of prodrugs, the function of which is to delay the onset and prolong the duration of action of the active substance.

Administration, Oral↗

PubMed2000

Lupin alkaloids from Chinese Maackia amurensis.

Two new alkaloids were isolated together with 16 known lupin alkaloids from the leaves and stems of Chinese Maackia amurensis. Their structures were determined by spectroscopic methods to be (-)-6alpha-methoxylupanine and (-)-5alpha-(12-cytisinylmethyl)-6alpha-hydroxylupan ine and identified by comparison with synthetic samples. The structures of lupin alkaloids were also related to the geographical distributions of the Maackia plants.

Alkaloids↗

PubMed2000

Sequential chemoimmunotherapy with cisplatin, interferon-beta and interleukin-2 inhibits the growth of B16-F1 melanoma in syngeneic mice.

Sequential combinations of chemotherapy with biological response modifiers has recently been evaluated as systemic treatment for patients with advanced melanoma. The response rates of the chemoimmunotherapy were reported to be higher than conventional treatment using chemotherapy or biological agents alone. To investigate the effectiveness of such chemoimmunotherapy, we evaluated the antitumour effect of sequential chemoimmunotherapy in vivo using a B16 mouse melanoma system. In this sequential regimen, administration of cisplatin (CDDP) was followed by interferon-beta (IFNbeta) and interleukin-2 (IL-2). This combination therapy synergistically inhibited the growth of B16-F1 melanoma and prolonged the survival of mice bearing B16-F1. In contrast, this therapy did not show any antitumour effect on B16-F10 melanoma. The exact mechanism of the antitumour effect is not clear, but the following results were noted: no synergistic effect of this therapy was detected in nude mice, neutralizing anti-IFNgamma antibody significantly blocked the antitumour effect of this therapy, and the number of apoptotic melanoma cells was significantly increased in melanoma tissues removed from mice treated with this therapy. These results demonstrated the potent immunological antitumour effect of this sequential chemoimmunotherapy.

Animals↗

PubMed2000

[Successful treatment for descending necrotizing mediastinitis: a case report].

A 21-year-old female was admitted to our hospital because of high fever, neck swelling, and dyspnea. She was diagnosed as descending necrotizing mediastinitis (DNM) extended from odontogenic infection. On the day of admission, she underwent cervical drainage. Next day, the CT scan showed an abscess below the tracheal bifurcation and bilateral pleural effusion. Mediastinal drainage was performed through a right thoracotomy, and a left thoracic tube was inserted. Anaerobic Peptostreptococcus was found with bacteriological culture. After the mediastinal drainage, bilateral thoracic irrigation was performed through the thoracic tubes. Left thoracic tube was removed on the 8th day and right one was removed on the 20th day after the thoracotomy. She was discharged on the 42nd day. DNM is relatively rare, but it is lethal disease with high mortality. Immediate and sufficient mediastinal drainage is indispensable for the disease.

Abscess↗

PubMed2000

[Clinical analysis of patients referred for lung transplantation in eastern Japan].

We investigated the indications for lung transplantation (LTx) in Japan and discussed questions regarding the current Japanese criteria of LTx. This study examined 37 patients referred to our institute for LTx. Among these patients, there were 11 cases of primary pulmonary hypertension (PPH), 6 of lymphoangiomyomatosis (LAM), 4 of Eisenmenger's syndrome, 3 of bronchiolitis obliterans, 2 each of bronchiectasis, idiopathic pulmonary fibrosis (IPF), and pneumoconiosis, and 7 of other diseases. The most frequent age group was 30-39 years (12 cases, 32.4%), and more than half of the patients were female (22 cases, 59.5%). The regions of residence of the patients were Tohoku (19 patients), Kanto (16), and Chubu (2). Patients were referred from all over eastern Japan. On evaluation, LTx was contraindicated in 5 cases, in 4 of which mechanical ventilation had been installed before consultation with us. Six patients died before registration on the Japan Organ Transplant Network (JOT). 6 transplant candidates were registered with JOT, but one (PPH) died after 6 months of waiting, and one (LAM) received a lung transplant from a brain dead cadaver donor. We propose to reform and clarify the Japanese criteria for LTx-both indications and contraindications, to include such indications as a survival probability of less than two years, and such contraindications as mechanical ventilation. Early consultation at LTx centers was hoped for, in accordance with the International Guidelines and a transplant window.

Adolescent↗

PubMed1999

Discordant and anomalous results among cytotoxicity assays: the confounding properties of eosinophil granule major basic protein on cell viability assays.

When five cytotoxicity methods compared the toxicity of eosinophil granule major basic protein (MBP) and melittin to K562 and HL-60 cells, strikingly discrepant results were noted. Trypan blue staining, propidium iodide/CellTrackerGreen staining and incorporation of 14C-leucine assays indicated MBP damages > 75% of cells by 1 h. In contrast, 51Cr and lactic dehydrogenase (LDH) release assays indicated MBP damages most cells only at 20 h. All methods indicated melittin damages nearly all cells by 1 h. Further studies showed that without cell transfer, dye staining methods indicated MBP produces < 10% cytotoxicity after 4 h. A modified 14C-leucine assay, employing sodium dodecyl sulfate solubilization and trichloroacetic acid precipitation, showed lower cytotoxicity, 48%, at 4 h. Modified 51Cr and LDH assays showed increased cytotoxicities at 4 h, 34% and 58%, respectively. Overall, MBP's ability to cause molecular and cellular adhesion systematically confounds standard cytotoxicity measurements. However, the modified 14C-leucine assay provides a valid measure of MBP's cytotoxicity and may be useful for analyses of 'sticky' cytotoxins.

Blood Proteins↗

PubMed1999

Analyses of oviductal pars recta-induced fertilizability of coelomic eggs in Xenopus laevis.

The acquisition of fertilizability in coelomic eggs of Xenopus laevis has been shown to be correlated with the physical, biochemical, and ultrastructural alterations of the egg envelope [coelomic envelope (CE)] induced during the passage of eggs through the pars recta portion of the oviduct. However, no direct evidence that the pars recta renders eggs fertilizable has yet been presented. In this study, we show that coelomic eggs are highly fertilizable when they are incubated with continuous shaking for 4 h at 15 degrees C in pars recta extract (PRE) derived from females prestimulated by pregnant mare serum gonadotropin. The PRE from pituitary-stimulated Bufo japonicus was as potent as homologous PRE in rendering Xenopus eggs fertilizable. Incubation of coelomic eggs in PRE for 30 min induced a dramatic increase in the rates of sperm binding to the envelope to a level equivalent to that exhibited by the envelope from uterine eggs (VEs). The CE-to-VE ultrastructural conversion and a 43k-to-41k hydrolysis of the envelope glycoprotein component started 5 min after, and were completed by 15 min after, the start of incubation in PRE and were accompanied by an exposure of a new N-terminal sequence typical to gp41. Thus, the biochemical and ultrastructural conversions and the sperm-binding activity of the envelope induced by PREs, although being prerequisite, were not sufficient to render coelomic eggs fully accessible to fertilizing sperm.

Animals↗

PubMed1999

Evaluation of colonic absorbability of drugs in dogs using a novel colon-targeted delivery capsule (CTDC).

A series of dog studies were performed to examine the in vitro/in vivo relationship of drug release behavior of the newly developed colon-targeted delivery capsule (CTDC). The four kinds of CTDCs containing theophylline, each of which has a different in vitro dissolution lag time, were orally administered to four beagle dogs under fasted condition, and the onset times of drug absorption were compared. The CTDC with longer in vitro lag time had a later onset of drug absorption. It was also found that the time difference between the gastric emptying and the onset of drug absorption was almost equal to the in vitro dissolution lag time of the capsule, suggesting a similar performance of CTDC in the gastrointestinal tract. From the comparison to the absorption behavior of the colon arrival marker, i.e. sulfasalazine, it was proved that the CTDC with the lag time of 3 h can deliver the drug directly to the colon. This result implied that the CTDC can be used as a non-invasive means for assessing the regional absorbability of drugs in the gastrointestinal tract. To evaluate the absorbability of drugs in the colon, three model drugs, theophylline (THEO), acetaminophen (ACET), and phenylpropanolamine hydrochloride (PPA) were directly delivered to the colons of beagle dogs using the CTDC with the lag time of about 3 h. The obtained relative bioavailabilities to the solution form were as high as 94.2%, 71.0%, and 91.5% for THEO, ACET and PPA, respectively, suggesting that the colonic absorbability of those drugs is essentially good.

Absorption↗

PubMed1999

Molecular basis for oviductin-mediated processing from gp43 to gp41, the predominant glycoproteins of Xenopus egg envelopes.

Acquisition of fertilizability in Xenopus coelomic eggs is correlated with the conversion from coelomic to vitelline envelope during passage of the eggs through the pars recta portion of oviduct. The conversion includes processing of a major envelope constituent gp43 of coelomic envelopes to gp41 of vitelline envelopes by a trypsin-type protease, oviductin, which is secreted from the pars recta. Our recent sequencing analyses [Kubo et al., (1997): Dev Growth Diff 39:405-411] strongly suggested that the N-terminal portion of gp41 is exposed as a result of oviductin digestion. In this study, a monoclonal antibody specific to the predicted N-terminus of gp41 was raised by immunizing mice with a synthetic N-terminal hexapeptide (QLPVSP) coupled to keyhole limpet hemocyanin. The antibody specifically reacted to gp41, but not to gp43, indicating that Gln62 is exposed as the N-terminal amino acid of gp41 by oviductin-mediated cleavage of gp43 at Arg61 in GSR61. The C-terminal sequencing of gp43 and gp41 indicated that Arg373 in GSR373 as the C-terminus of gp41 is generated by cleavage of three amino acid (WNQ) residues from the C-terminus of gp43. The resulting polypeptide moiety of gp41 has a molecular mass of 33900 Da with 312 amino acid residues. We propose that oviductin possessing the substrate specificity of GSR simultaneously digests gp43 at Arg residues in GSR61 and GSR373 to generate the N- and C-terminus of gp41, respectively.

Amino Acid Sequence↗

PubMed1999

Superoxide anion mediates pulmonary vascular permeability caused by neutrophils in cardiopulmonary bypass.

During cardiopulmonary bypass (CPB), neutrophils (PMNs) may be stimulated by shear stress which could contribute to the pulmonary injury that occurs after CPB. To elucidate whether mechanically stimulated PMNs increase pulmonary vascular permeability, measured as the pulmonary filtration coefficient (K) and pulmonary vascular resistance, and to elucidate whether superoxide anion mediates this increase, we assessed the effects of stimulated and unstimulated PMNs, and of superoxide dismutase (SOD) on K and resistance in isolated perfused lungs from Sprague-Dawley rats. PMNs were stimulated by gentle agitation in a glass vial for 10 s. Lungs perfused with the stimulated PMNs, being the stimulated group (n = 6), elicited a 5-fold increase in the filtration coefficient compared with lungs perfused with unstimulated cells, being the unstimulated group (n = 6). This increase in filtration was completely blocked by the preincubation of stimulated PMNs with CD18 monoclonal antibody, being the Ab group (n = 6), and also by superoxide dismutase, being the SOD group (n = 6). Pulmonary vascular resistance was not increased by stimulated PMNs, and the accumulation of stimulated PMNs was not blocked by SOD. These findings suggest that stimulated PMNs increase K and that superoxide anion may injure the pulmonary vascular endothelial cells.

Analysis of Variance↗

PubMed1999

Successful resection of endotracheal papillary adenocarcinoma by endoscopic electrosurgery using a new snare: report of a case.

We report herein the rare case of a patient with endotracheal papillary adenocarcinoma of the goblet cell type. The tumor existed in the upper trachea, obstructing 95% of the airway, and prompt palliation was required. Endotracheal polypectomy was successfully performed in this patient using electrosurgery with a new snare designed for the respiratory tract. The procedure took only a few minutes and the dyspnea was relieved promptly without any complications. The alternative techniques for palliation of bronchial stenosis are also discussed.

Adenocarcinoma, Papillary↗

PubMed1999

Functional evaluations for pulmonary resection for lung cancer in octogenarians. Investigation from postoperative complications.

We have reviewed the records of our twenty-four patients aged 80 years or older who underwent lung resections for bronchogenic carcinoma between 1983 and 1997 in our department. Eighteen patients were male and six were female. Adenocarcinoma was the histology in more than half of the cases (13 patients), along with 8 squamous cell carcinoma, 2 large cell carcinoma, and one small cell lung carcinoma. More than single lobectomy was performed in each patient. Unilateral pulmonary occlusion tests were employed in patients with impairment in pulmonary functions. Every patient, who underwent the unilateral pulmonary occlusion test, was certified that the total pulmonary vascular resistance index during unilateral pulmonary arterial occlusion test was less than 700 dyne.sec.cm-5.m2. Postoperative cardiovascular complications, such as paroxysmal atrial tachycardia, premature atrial contraction, premature ventricular contraction or atrial fibrillation, were seen in 10 patients. Postoperative respiratory complications, namely, sputa retention, retained secretions or atelectasis, were seen in 7 patients. The extent of dissection of mediastinal lymph node was not correlated to the postoperative pulmonary complications. However, the incidence of arrhythmias in the patients who received R2 mediastinal lymphnode dissection was much higher than in those who received R1 or R0 dissection. Complete blood counts and serum biochemical analysis performed at about three weeks after operations revealed leukocytosis and increases in levels of serum transaminase. These phenomena in leukocytosis and increases in the levels of serum transaminase in these patients were similar to those in younger patients. There was no operative death. We conclude that some patients over 80 years are candidates for lung resection after careful preoperative cardiopulmonary evaluation.

Adenocarcinoma↗

PubMed1999

Evaluation of free radical scavenging activities of antioxidants with an H(2)O(2)/NaOH/DMSO system by electron spin resonance.

An H(2)O(2)/NaOH/DMSO system has been developed for the formation of three free radicals, and the application of the system was examined with the antioxidants ascorbic acid and tocopherol. Superoxide anion, hydroxyl radical,and methyl radical are simultaneously generated in this system. The scavenging activity of ascorbic acid and tocopherol for these radicals was estimated by 5, 5'-dimethyl-1-pyrroline-N-oxide spin trapping electron spin resonance. Both water-soluble and oil-soluble antioxidants could be evaluated by using this system. Ascorbic acid specifically inhibited the superoxide anion and hydroxyl radical, whereas tocopherol suppressed the methyl radical.

Antioxidants↗

PubMed1999

Preimplantation diagnosis by fluorescence in situ hybridization using 13-, 16-, 18-, 21-, 22-, X-, and Y-chromosome probes.

PURPOSE: Our purpose was to select the proper chromosomes for preimplantation diagnosis based on aneuploidy distribution in abortuses and to carry out a feasibility study of preimplantation diagnosis for embryos using multiple-probe fluorescence in situ hybridization (FISH) on the selected chromosomes of biopsied blastomeres. METHODS: After determining the frequency distribution of aneuploidy found in abortuses, seven chromosomes were selected for FISH probes. Blastomeres were obtained from 33 abnormal or excess embryos. The chromosome complements of both the biopsied blastomeres and the remaining sibling blastomeres in each embryo were determined by FISH and compared to evaluate their preimplantation diagnostic potential. RESULTS: Chromosomes (16, 22, X, Y) and (13, 18, 21) were selected on the basis of the high aneuploid prevalence in abortuses for the former group and the presence of trisomy in the newborn for the latter. Thirty-six (72%) of 50 blastomeres gave signals to permit a diagnosis. Diagnoses made from biopsied blastomeres were consistent with the diagnoses made from the remaining sibling blastomeres in 18 embryos. In only 2 of 20 cases did the biopsied blastomere diagnosis and the embryo diagnosis not match. CONCLUSIONS: If FISH of biopsied blastomere was successful, a preimplantation diagnosis could be made with 10% error. When a combination of chromosome-13, -16, -18, -21, -22, -X, and -Y probes was used, up to 65% of the embryos destined to be aborted could be detected.

Abortion, Spontaneous↗

PubMed1999

Effects of ONO-1078 (pranlukast) on cytokine production in peripheral blood mononuclear cells of patients with bronchial asthma.

BACKGROUND: ONO-1078 (pranlukast) is a leukotriene receptor antagonist developed in Japan. This drug has been shown to be useful in oral treatment of bronchial asthma. The present study was undertaken to assess the effects of this drug on the production of cytokines in the peripheral blood mononuclear cells of patients with asthma under stimulation with specific antigens. METHODS: Peripheral blood mononuclear cells from mite antigen-positive asthmatic patients (immunoglobulin E RAST score > 3) were incubated for 72 h in the presence of mite antigen (10 microg/mL). The supernatant of the culture was subjected to enzyme-linked immunosorbent assay (ELISA) to quantify interleukin (IL) -4, IL-3, IL-5, and granulocyte macrophage-colony stimulating factor (GM-CSF). Other peripheral blood mononuclear cells from the same patients were incubated for 72 h in the presence of both mite antigen (10 microg/mL) and ONO-1078 (0.5, 1, or 10 microg/mL), followed by ELISA of the supernatant to quantify the cytokines. RESULTS: Production of IL-4, IL-5, and GM-CSF by mononuclear cells under stimulation with mite antigen was markedly suppressed when they were exposed to ONO-1078 at a concentration of 10 microg/mL. CONCLUSION: The results suggest that ONO-1078 acts directly on peripheral blood mononuclear cells and that blockade of leukotriene receptors on blood mononuclear cells by the cysteinyl-leukotriene receptor antagonist (LTRA) pranlukast (ONO-1078) can dose-dependently inhibit release of immunoreactive TH2-type cytokines (IL-3, IL-4, GM-CSF, and possibly IL-5), but not of the TH1-type cytokine IL-2, when stimulated by mite allergen in vitro. The data may provide clues to the mechanism by which a number of LTRA including zafirulukast and montelukast can reduce airway, sputum and blood eosinophil counts in clinical asthma. It supports animal studies showing that anti-IL-5 antibodies partially block cys-LT-induced airway eosinophilia, suggesting that cys-LTs may cause secondary release of IL-5 from an unknown cell-type. These findings indicate that ONO-1078 suppresses the production of IL-4 (a cytokine that affects IgG antibody production), IL-5, and GM-CSF (cytokines that affect eosinophil activation) by peripheral blood mononuclear cells under stimulation with specific antigens in patients with bronchial asthma. Because of its anti-inflammatory effects, ONO-1078 should be useful in the treatment of bronchial asthma.

Adult↗

PubMed1999

Sleep stage and skin temperature regulation during night-sleep in winter.

To clarify the thermally comfortable environment for satisfied sleep, we investigated the relationship between skin temperatures and sleep stages during night-sleep in winter, summer and autumn. Four healthy young females served as the subjects. The experiments were performed in a climate chamber under three conditions: at 13 degrees C-RH70% with futon and blanket in winter, at 20-18 degrees C-RH60% with futon and towelket in autumn and at 29 degrees C-RH70% with towelket in summer. The subjects' skin temperature on the sole was lower until about 4 hours after lights off in winter than in autumn and summer, and the percentage of st.2 was lower and st.4 was higher in winter than in autumn and summer, although the bed climate both in winter and autumn was much the same.

Adult↗

PubMed1999

Lateralized memory deficits on the Wada test correlate with the side of lobectomy only for patients with unilateral medial temporal lobe epilepsy.

The aim of this study was to determine whether the predictive value of the intracarotid amobarbital test (IAT) for the side to be resected is applicable only to medial temporal lobe epilepsy and to investigate whether there are different patterns of memory performances on the IAT between patients with unilateral mesial temporal sclerosis (UMT group) and those without (non-UMT group). We studied 30 patients in the UMT group and 10 in the non-UMT group, who underwent pre-surgical evaluation for intractable temporal lobe epilepsy. Memory performances on the IAT was defined as the percentage of memory items presented during unilateral hemispheric anesthesia that was recognized after recovery. More than a 20% decline of the memory performance on the IAT compared with the memory performance on the pre-test was regarded as a memory deficit. Age at onset of epilepsy was significantly younger in the UMT than in the non-UMT group. Surgical outcome was significantly better in the UMT than in the non-UMT group. The lateralizing value of unilateral memory deficits on the IAT was statistically confirmed. There was a significant association between falsely lateralizing memory performances and the non-UMT group. Excluding the exceptional cases with right-sided language dominance in spite of right-sided lesions, the high incidence of the unilateral right-sided memory deficits in the non-UMT group was statistically significant. This study suggested that the excellent lateralizing value of the memory performances on the IAT is limited to patients with mesial temporal lobe epilepsy. IAT memory performances in patients without such lesions can be misleading, even if lateralized, because their memory status presumably reflects a natural lateralization of the memory organization which is independent of the epileptogenic focus.

Adult↗

PubMed1999

kappa-Opioid receptor-mediated antinociceptive effects of stereoisomers and derivatives of (+)-matrine in mice.

The antinociceptive effects of seven matrine-type lupin alkaloids were examined using the acetic acid-induced abdominal contraction test (the writhing test) and the tail-flick test in mice. (+)-Allomatrine, the C-6 epimer of (+)-matrine, produced the antinociceptive effect at 1/3 potency of (+)-matrine or pentazocine. It was demonstrated that the antinociceptive effects of (+)-allomatrine were mediated through the activation of kappa-opioid receptors, while the antinociceptive effect of (+)-matrine was mediated by both mu- and kappa-opioid receptors. (-)-Sophoridine, the C-6 epimer of (+)-matrine, (+)-sophoranol, (-)-14 beta-hydroxymatrine and (+)-matrine N-oxide, which possess a hydrophilic group, and (-)-sophocarpine and (-)-sophoramine having a double bond(s) did not show significant antinociceptive activity.

Alkaloids↗