Biomedical subjects

K Kubo

Publications and source records attributed to K Kubo.

At least 235 records · Page 13Linked to original sources

PubMed1998

The Fas system is not significantly involved in apoptosis in human hepatocellular carcinoma.

We investigated the role of apoptosis in relation to proliferative activity in hepatocellular carcinoma (HCC) using in situ DNA nick end labeling (ISNEL) and immunostaining for the Ki-67 antigen in 35 patients with HCC. We also performed immunostaining for Fas and Fas ligand (Fas L) to determine the relationship between the Fas system and apoptosis. The ratio of the ISNEL labeling index (LI) to the Ki-67 LI was significantly lower in HCC than in surrounding nontumorous liver tissue (p<0.0001), suggesting that a decrease in apoptosis relative to cell proliferation is important in the pathogenesis of HCC. Fas and Fas L were expressed in both HCC and nontumorous tissue, but Fas and Fas L LIs were significantly lower in HCC (p<0.0001). Fas expression by cells near ISNEL-positive cells tended to be increased in nontumorous tissue in mirror-image sections, suggesting that apoptosis is related to Fas expression. However, this pattern was rarely observed in HCC. These findings indicate that the Fas system may not play a major role in apoptosis in HCC.

Aged↗

PubMed1998

Pharmacokinetic evaluation of amphotericin B in lung tissue: lung lymph distribution after intravenous injection and airspace distribution after aerosolization and inhalation of amphotericin B.

We have studied the pharmacokinetics of amphotericin B (AmB) in lung lymph circulation and bronchial-wash fluid after intravenous infusion and inhalation, respectively. For two experiments with awake sheep, we used lung lymph fistulas and tracheotomy. In experiment 1, AmB concentrations in plasma and lung lymph after intravenous infusion of AmB (1 mg/kg of body weight) over 1.5 h were measured. The mean peak in plasma level was 756.0 +/- 188.8 ng/ml at 3 h after the start of infusion, and the level then decreased gradually to 194.8 +/- 28.9 ng/ml at 24 h. The stable and maximal levels in lung lymph last 5 to 9 h after the start of AmB infusion. The concentrations in lung lymph after 9 h were slightly higher than those in plasma. Thus, the lung lymph-to-plasma ratio of AmB concentrations increased gradually during infusion, and the ratio was more than 1.0 after the end of infusion, suggesting that AmB could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. In another experiment, 5 or 30 mg of aerosol AmB was inhaled, and the concentration of AmB in the bronchial-wash fluid was determined by bronchoalveolar lavage. The peak AmB concentration in the fluid was observed at 0.5 h. After that, AmB was slowly eliminated over 24 h. The area under the concentration-time curve for 30 mg of inhaled AmB was higher than that for 5 mg, but maximum concentrations of AmB in serum for 5 and 30 mg were almost similar. These observations identify the pharmacokinetic characteristics of AmB in the lung and may provide a new insight into the strategy for clinical treatment of fungal pneumonia.

Administration, Inhalation↗

PubMed1998

Blunted hypoxic pulmonary vasoconstrictive response in the rodent Ochotona curzoniae (pika) at high altitude.

To investigate the possible mechanisms of adaptation to chronic hypoxia in the pulmonary circulation, we made direct measurements of pulmonary arterial pressure (Ppa) in 10 awake pika rodents that were transported to Xining, People's Republic of China (altitude 2,260 m) after being captured at 4,300 m and in 10 Wistar rats in a decompression chamber (simulated altitudes of 4,300 and 5,000 m) in Xining. Ppa was obtained at 1 h of exposure to each simulated altitude. The histology and immunohistochemistry of the lung tissues were also studied. Ppa in the pikas after the 4,300- and 5,000-m altitude exposures did not significantly increase, whereas in the rats Ppa rose significantly. Mean changes in Ppa from 2,260 to 4,300 and 5,000 m were 1.48 +/- 0.49 and 4.80 +/- 0.67 mmHg in the pikas and 10.38 +/- 3.36 and 19.10 +/- 2.28 mmHg in the rats. The ratio of right ventricular to left ventricular plus septal weight in the pikas and rats was 0.22 and 0.45, respectively. The pikas maintained levels of Hb, hematocrit, and 2,3-diphosphoglycerate lower than those of the rats. The percent wall thickness of the small pulmonary arteries in the pikas and rats was 9.22 and 27.21%, respectively, and it was well correlated with the degree of Ppa in both groups. Mast cells were observed in the lungs of the rats (7.1 +/- 0.33 cells/mm2) but not in the pikas. There was highly positive staining for mast cell tryptase and transforming growth factor-beta around pulmonary vessels in the rats, whereas no demonstrable reaction was observed in the pikas. We conclude that the pika has adapted to high altitude by losing hypoxic pulmonary vasoconstriction and thin-walled pulmonary arterioles.

Animals↗

PubMed1998

Acetylcholine stimulates alveolar macrophages to release inflammatory cell chemotactic activity.

Neurological transmitters including ACh, substance P (SP), and calcitonin gene-related peptide (CGRP) play an important role in regulating airway tone, and increased bronchial reactivity to cholinergic stimulation is a well-recognized phenomenon in patients with bronchial asthma. We postulated that ACh, SP, and CGRP might stimulate alveolar macrophages (AMs) to release neutrophil, monocyte, and eosinophil chemotactic activities. To test this hypothesis, bovine AMs were isolated by bronchoalveolar lavage and cultured. AMs released chemotactic activities in response to ACh in a dose- and time-dependent manner (P < 0.05). However, SP and CGRP did not stimulate bovine AMs. Checkerboard analysis revealed that these released activities were predominantly chemotactic. Partial characterization and molecular-sieve column chromatography revealed that low-molecular-weight lipid-soluble activity was predominant. Lipoxygenase inhibitors significantly blocked the release of chemotactic activities (P < 0.05). Leukotriene B4- and platelet-activating factor-receptor antagonists blocked the chemotactic activities. Immunoreactive leukotriene B4 significantly increased in supernatant fluids in response to ACh (P < 0.05), but platelet-activating factor did not. The receptor responsible for the release of the chemotactic activities was the muscarinic M3 receptor. These data demonstrate that ACh stimulates AMs to release lipoxygenase-derived chemotactic activities and plays a role in inflammatory cell recruitment into the airway.

Acetylcholine↗

PubMed1998

Human lung fibroblasts release chemokinetic activity for monocytes constitutively.

We determined whether human lung fibroblasts (HLFs) might release mediators that are responsible for monocyte chemokinetic activity (MCA) constitutively. HLF supernatant fluids showed MCA in a time-dependent manner (P < 0.001). Checkerboard analysis of 24- and 72-h supernatant fluids showed that the activity was chemokinetic. Partial characterization of 24- and 72-h supernatant fluids revealed that the mediators released after 24 h were predominantly composed of lipid-soluble activity, and MCA was blocked by lipoxygenase inhibitors. The mediators released after 72 h were predominantly trypsin sensitive and blocked by cycloheximide. Molecular-sieve column chromatography identified four peaks of MCA. A polyclonal antibody to monocyte chemoattractant protein-1 (MCP-1) inhibited MCA by 20% after 24 h and by 40% after 72 h. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor-beta (TGF-beta) antibodies attenuated MCA released after 72 h by 30 and 10%, respectively. These antibodies inhibited corresponding molecular-weight peaks separated by molecular-sieve column. The concentrations of MCP-1, GM-CSF, and TGF-beta were 4,698 +/- 242, 26.8 +/- 3.8, and 550 +/- 15 pg/ml, respectively. A leukotriene B4 (LTB4)-receptor antagonist attenuated the total MCA and the lowest molecular weight peak of MCA. The concentrations of LTB4 were 153.4 +/- 12.4 (24 h) and 212 +/- 16.6 (72 h) pg/ml. These findings suggest that HLFs may modulate the recruitment of monocytes into the lung by releasing MCP-1, GM-CSF, TGF-beta, and LTB4 constitutively.

Adult↗

PubMed1998

Alveolar type II-like cells release G-CSF as neutrophil chemotactic activity.

We evaluated the potential of A549 cells, an alveolar type II epithelial cell line, to release granulocyte colony-stimulating factor (G-CSF), in addition to interleukin (IL)-8 and leukotriene B4, as neutrophil chemotactic activity (NCA). Human recombinant IL-1beta stimulated A549 cells to release NCA in a time- and dose-dependent fashion. The released NCA was blocked by mouse anti-human G-CSF polyclonal antibody. Molecular-sieve column chromatography revealed that IL-1beta induced the release of a 19- to 20-kDa chemotactic mass that was inhibited by anti-human G-CSF antibody. IL-1beta stimulated the release of G-CSF in a dose-dependent fashion, but the time-dependent profile of G-CSF showed that the concentration of G-CSF declined after 48 h. Tumor necrosis factor (TNF)-alpha, Escherichia coli lipopolysaccharide (LPS), and bradykinin (BK) stimulated A549 cells to release NCA that was inhibited by anti-G-CSF antibody. The release of G-CSF in response to TNF-alpha, LPS, and BK was significantly increased. The similar concentrations of human recombinant G-CSF (10-1,000 pg/ml) as in the supernatant fluid induced neutrophil chemotaxis. G-CSF mRNA was expressed time and dose dependently at 4 h and declined after 4 h in response to IL-1beta as evaluated by RT-PCR. The expression of G-CSF mRNA was also observed by TNF-alpha, LPS, and BK stimulation. These data suggest that type II alveolar epithelial cells may produce G-CSF as NCA and may participate in the regulation of leukocyte extravasation.

Animals↗

PubMed1998

Acetylcholine and substance P stimulate bronchial epithelial cells to release eosinophil chemotactic activity.

We investigated a role of neuroregulation in the release of eosinophil chemotactic activity (ECA) from bovine bronchial epithelial cells (BBEC). BBEC were stimulated with acetylcholine (ACh) and substance P (SP), and the supernatant fluids were tested for ECA by a blind-well chemotactic chamber technique. BBEC released ECA in response to ACh and SP in a dose- and time-dependent manner. Checkerboard analysis showed that ECA in regard to ACh and SP was chemotactic rather than chemokinetic. Partial characterization revealed that ECA involved both lipids and peptides. The release of ECA in response to ACh and SP was inhibited by nonspecific and 5-specific lipoxygenase inhibitors and by cycloheximide (P < 0.01). Molecular-sieve column chromatography revealed that these mediators induced three molecular mass peaks (near 25 kDa, 9 kDa, and 400 Da, respectively). The lowest peak, which represented the predominant activity, was blocked by leukotriene B4-receptor antagonist (P < 0. 01) but not by platelet-activating factor-receptor antagonist. The release of leukotriene B4 in the supernatant fluids was increased in response to ACh and SP stimulation (P < 0.01). Platelet-activating factor was not detected. These results raise the possibility of a role of neuroregulation for the elaboration of ECA in the airway.

Acetylcholine↗

PubMed1998

Pulmonary infection with Mycobacterium avium-intracellulare leads to air trapping distal to the small airways.

To clarify the structure and function of the airways in Mycobacterium avium-intracellulare (MAI) infection, we performed pulmonary function tests and high-resolution computed tomography (HRCT) of the thorax in female patients 61 +/- 9 yr of age (n = 12) with pulmonary MAI infection without predisposing lung disease and compared their data with those of normal female volunteers 54 +/- 8 yr of age (n = 9). We calculated the E/I ratio, i.e., the average ratio of HRCT number at full expiration to that at full inspiration, as an index for the evaluation of air trapping distal to the small airways. Patients showed significant increases in residual volume and slope of phase III (DeltaN2) of the single-breath nitrogen test, and significant decreases in flow at 50 and 25% of FVC, suggesting hyperinflation and obstruction of the small airways. HRCT of patients revealed the small nodules and ectasis of bronchioles and small bronchi located mainly in segments (S) S2, S3, S4, and S5. The E/I ratio was significantly elevated in patients, and especially higher in the upper lung field than in the lower lung field, suggesting air trapping distal to the small airways. The difference of E/I ratio between the upper and lower field is probably related to the segmental distribution of CT abnormalities. These findings suggest that MAI infection can lead to air trapping distal to the small airways.

Airway Obstruction↗

PubMed1998

Analysis of BAL fluid in M. avium-intracellulare infection in individuals without predisposing lung disease.

The purpose of this study was to investigate the characteristics of pulmonary inflammation caused by Mycobacterium avium-intracellulare (MAI) in individuals with neither predisposing lung disease nor immunodeficiency. We reviewed the records of 20 patients with pulmonary MAI infection (including 19 female patients) whose past history and previous chest radiographs revealed no predisposing lung disease. We analysed the bronchoalveolar lavage fluid (BALF) from these 20 patients and from six normal female controls. The BALF was recovered directly from the relevant segment that was identified with chest-computed tomography. The BALF cell profiles showed significantly elevated counts for total cells, lymphocytes and neutrophils, but the macrophage cell count was not elevated. The CD4+ lymphocyte count and CD4+/CD8+ ratio were significantly increased compared with those in the controls. The lymphocytes demonstrated phenotypical evidence of activation, with increased expression of human leukocyte antigen-D-related antigen (HLA-DR). The tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-6 and IL-8 concentrations were significantly increased. The neutrophil elastase concentration was also increased, and it was significantly correlated with the neutrophil cell count in the BALF. These findings suggest that the increased counts of activated CD4+ lymphocytes and neutrophils and the elevated concentrations of proinflammatory cytokines and neutrophil elastase appear to be common characteristics in Mycobacterium avium-intracellulare infection.

Bronchoalveolar Lavage Fluid↗

PubMed1998

Enhanced in vitro percutaneous penetration of salicylate by ion pair formation with alkylamines.

The apparent octanol/water partition coefficient (APC) of salicylate (SA) increased as the concentration of alkylamine (amyl, hexyl, heptyl, octyl and nonylamine) in aqueous phase increased, presumably through intermolecular ion pair formation between the negatively charged SA moiety and the alkylamine cation. The true partition coefficient (TPC) and the formation constant (Kf) of the ion pair were calculated from the partition data. The skin permeability of SA increased as the APC of SA increased, when 20-fold molar excess of alkylamine was added to the donor compartment. Permeability of ion pairs (PAB) from the aqueous phase to a shed snake skin was estimated from the permeability data assuming 1:1 ion pair. The methylene group contribution to the free energy of transfer of ion pairs from water to the shed snake skin was less than the reported value for nonionized drugs. This suggests that the ion pair is more polar by nature than nonionized molecules, even if ionic characteristics are masked to some extent by ion pair formation.

Amines↗

PubMed1998

Dietary docosahexaenoic acid dose not promote lipid peroxidation in rat tissue to the extent expected from peroxidizability index of the lipids.

Docosahexaenoic acid (DHA) ingestion enhanced the susceptibility of rat liver and kidney to lipid peroxidation as a function of the dietary DHA level, but did not increase lipid peroxides as assessed by thiobarbituric acid (TBA) values to the level expected from the peroxidizability index of the tissue total lipids. This phenomenon was especially prominent in the liver. In the liver, the higher proportion of DHA in the non-phosphorus lipids might play an important role in lessening the susceptibility of the tissue to lipid peroxidation. In the brain and testis, on the other hand, lipid peroxide levels were decreased when DHA was given to the animals. In the testis, in particular, the proportion of DHA in total lipids was lowest among all tissues examined, even when a relatively high level of DHA had been ingested, and this could be related to the low lipid peroxide level. Therefore, the protection against lipid peroxidation differed from tissue to tissue, even from the viewpoint of the fatty acid composition of the tissue lipids. In addition, changes in the lipid peroxide levels of the liver, kidney, brain and testis, as assessed by TBA values, seemed to be associated with changes in the peroxidizability index of phosphatidylcholine (+cardiolipin) in each tissue.

Animals↗

PubMed1998

In vitro cytotoxicity of recombinant human-TNF-alpha and actinomycin D on canine normal and tumor cells.

The in vitro cytotoxicity of recombinant human tumor necrosis factor-alpha (rh-TNF-alpha) and actinomycin D (ACT-D) on canine normal and tumor cells was investigated. rh-TNF-alpha showed dose-dependent cytotoxic and cell-growth inhibitory effects on cultured canine kidney carcinoma cells (CKCa-1). rh-TNF-alpha alone produced little cytotoxic effect on canine normal cells. However, combined with ACT-D, it showed moderate cytotoxicity on normal canine cells from the kidney medulla, spleen, heart muscle and lung. When the effects on the spontaneous tumor cells were examined, the combination of rh-TNF-alpha and ACT-D produced substantial cytotoxic effect on 60% of the tumor cells. All mammary mixed tumors and perianal gland tumors tested were susceptible to this combination. The data indicated the combination of rh-TNF-alpha and ACT-D have in vitro cytotoxicity on certain canine tumor cells.

Animals↗

PubMed1998

Induction of fragile sites by fluorodeoxyuridine and caffeine accompanies with misincorpolation of endogenous uridine nucleotide into DNA of feline fibroblasts.

Fluorodeoxyuridine, an inhibitor of thymidylate synthetase, is known to induce chromosomal fragile sites. The drug treatment may cause deprivation of intracellular thymidine nucleotide pool followed by a serious imbalance of deoxynucleotide pool. Though the stress is probably related to the induction of folate-sensitive fragile sites, the exact mechanism is still to be investigated. The present study has been carried out to test the possibility that the fragile sites are originated, at least in part, from incorpolated uracil residues. The incorpolated uracil residue can be detected by a novel assay for abasic sites after treatment with uracil-DNA N-glycosylase (UDG). About 2.7 abasic sites per 10(4) nucleotides were detected in the DNA extracted from feline fibroblasts after the treatment with FUdR and caffeine. By digesting the DNA with UDG prior to the assay, significant increase in the number of abasic sites were observed. These results indicate that the large amount of uracil residues are present in the feline fibroblast DNA under the condition which induces chromosomal fragile sites.

Animals↗

PubMed1998

Frequent expression of the c-kit proto-oncogene in canine malignant mammary tumor.

The mammary tumor is one of the popular neoplastic diseases in female dogs. In the present study, the expression of canine c-kit proto-oncogene in mammary tumor specimens was investigated to evaluate its potential usefulness as a tumor marker. By comparing the homology among the nucleotide sequences reported for human mouse, rat and feline c-kit c-DNA, a pair of primers was synthesized for the reverse transcriptase-polymerase chain reaction (RT-PCR) method. The RT-PCR product of canine spleen total RNA was shown to have 756 bp in size and to be highly homologous to the corresponding sequences reported for the mammalian species. The expression of c-kit transcript was detected in 11 mammary tumors of different histopathology including adenocarcinomas, benign and malignant mixed tumors. The level of the transcription in adenocarcinomas was significantly higher than those in malignant mixed tumors. Fifteen canine tumor specimens originated from various tissues were also tested for their c-kit transcript. In all of the mastocytoma samples examined, high expression of the mRNA was detected. Of other 12 tumors, only low level of RT-PCR products were detected in 5 samples, whereas no apparent amplification was observed in 7 tumors. These results indicate that the high expression of c-kit transcript is helpful for the diagnosis of canine mammary tumors.

Animals↗

PubMed1998

Novel putative fragile sites observed in feline fibroblasts treated with aphidicolin and fluorodeoxyuridine.

Fragile sites are non-randomly distributed chromosomal breaks and gaps observed in the cells cultivated under certain conditions. Feline fragile sites were analyzed using skin fibroblast strains after the treatments with aphidicolin and fluorodeoxyuridine in combination with caffeine. Three aphidicolin-induced fragile sites (A1q21, C2q13 and E1p21) as well as a folate-sensitive site (B1q14) were observed in all the 3 fibroblast strains tested for each treatment group. The loci in A1q21 and B1q14 are very close to that reported previously for peripheral blood lymphocytes and lung cells. Two chromosomal break points in C2q13 and E1p21 seem to be new fragile sites. Fifteen candidates for feline fragile sites were also assigned their locations in feline chromosomes. Both the incidence and distribution of feline fragile sites in skin fibroblasts seem to be different at least in part from those in lymphocytes.

Animals↗

PubMed1998

Cytotoxicity induced by recombinant human tumor necrosis factor-alpha dependent on the types of its receptors on canine cells.

Based on the recent findings that show how recombinant human tumor necrosis factor (rh-TNF)-alpha has potent antitumor activity on human cancer patients when it locally administrated, we have tested the cytotoxicity of rh-TNF-alpha on 3 canine cultured cells: (1) canine kidney carcinoma (CKCa-1), (2) mastocytoma and (3) Mardin Darby canine kidney cells (MDCK). The cell surface expression of TNF-alpha receptors on these canine cells was also determined with anti-human TNF RI and RII polyclonal antibodies. Our data shows that on CKCa-1 which has TNF RI receptors rh-TNF-alpha induced cytotoxicity. By contrast, it exhibited no toxicity on canine mastocytoma which has mainly RII receptors. The data also suggest actinomycin D (ACT-D), an anticancer antibiotic, enhanced the cytotoxicity of rh-TNF-alpha. Combined with ACT-D, rh-TNF-alpha showed the cytotoxicity on MDCK which possessed both TNF RI and RII receptors. The results indicate that the cytotoxicity of rh-TNF-alpha depends on the presence of TNF RI receptors on canine tumor cells.

Animals↗

PubMed1998

Effects of lung volume reduction surgery on exercise pulmonary hemodynamics in severe emphysema.

STUDY OBJECTIVES: To clarify the effects of lung volume reduction surgery (LVRS) on pulmonary hemodynamics in severe emphysema and to evaluate the role of pulmonary circulation in the increased exercise performance after LVRS. DESIGN: In eight male patients with severe emphysema, we measured pulmonary artery (Ppa) and occlusion (Pop) pressures and cardiac output through a Swan-Ganz thermodilution catheter, and we calculated cardiac index (CI), pulmonary vascular resistance index, and driving pressure. The study was performed at rest and during exercise using a supine bicycle ergometer at 25 W, under room air and O2 inhalation. Exercise performance was expressed as endurance time in minutes. Pulmonary function tests were performed. The patients underwent an identical study before and 6 months after LVRS. RESULTS: The patients' exercise performance was significantly increased after LVRS (5.9+/-1.8 min) compared with that before LVRS (3.6+/-0.9 min). LVRS resulted in a significant increase in FEV1 and a significant decrease in residual volume. Before LVRS, Ppa was increased both at rest and during exercise. LVRS did not change rest or exercise Ppa. LVRS significantly decreased Pop during exercise from 24+/-10 mm Hg to 18+/-7 mm Hg. CI at rest and during exercise were significantly increased after LVRS. O2 administration significantly decreased Ppa during exercise both before and after LVRS. CONCLUSIONS: These findings suggest that LVRS does not improve pulmonary hypertension at rest or during exercise in patients with severe emphysema and that elevated Pop during exercise before LVRS is probably related to lung mechanic abnormalities.

Aged↗

PubMed1998

Spontaneous pneumomediastinum: origin identified by chest computed tomography.

Spontaneous pneumomediastinum (SPM) is an uncommon disorder. The mechanism of spontaneous pneumomediastinum has been speculated as follows: when air pressure in the alveoli rapidly increases, free air leaks from ruptured alveoli and accumulates along the bronchovascular tissue sheath, and then free air moves toward the mediastinum. In this case report of a 19-year-old man of SPM, a chest computed tomography (CT) revealed air in a tubular shape along the pulmonary artery in the apico-posterior segment of the left lung field. This is the first case in which the process of SPM could be identified by chest CT.

Adult↗