Biomedical subjects

T Akino

Publications and source records attributed to T Akino.

At least 55 records · Page 3Linked to original sources

PubMed1996

The differences in the expressions of visual pigments and transducin in photoreceptor cell differentiation.

The distribution and accumulation of visual pigments, i.e., rod pigment, rhodopsin and red sensitive cone pigment, iodopsin, and transducin in the retina of chicken and chicken embryo were investigated immunohistochemically using their specific antibodies. The immunoreactivities of these proteins appeared at the early stage of photoreceptor differentiation (embryonal day 15) and increased in the photoreceptor cells appeared to reach maximum at the end of the embryonal period (embryonal day 20). On the other hand, although the immunoreactivity of beta gamma subunit of transducin (T beta gamma) was detected at embryonal day 15, the expression level of T beta gamma still remained in low level during the embryonal period. These observations suggest that both T beta gamma and visual pigments are expressed during the embryonic period in chicken photoreceptor cells, but their accumulations in the cells are different.

Animals↗

PubMed1996

Nerve-regenerating effect of 15-deoxyspergualin. Peripheral nerve allotransplants in the rat.

We studied the effect of two immunosuppressive agents, 15-deoxyspergualin and cyclosporine A, on various nerve allografts in inbred rats whose major histocompatibility complex was mismatched. As allografts, we used the sciatic nerve (20 mm) and the saphenous nerve (20 mm). We found that 1) fresh peripheral nerve allografts with a short course of 15-deoxyspergualin and cyclosporine A therapy induced more regenerated axons than autografts did, 2) a short course of 15-deoxyspergualin therapy provided better nerve regeneration than cyclosporine A therapy in all forms of nerve allografts and large caliber nerve allografts induced more regenerated axons.

Animals↗

PubMed1996

Overexpression of surfactant protein SP-A, SP-B, and SP-C mRNA in rat lungs with lipopolysaccharide-induced injury.

Regeneration of alveolar epithelial cells is one of the important repair processes in many types of lung injury. We have examined sequential analysis of histopathology and gene expressions of surfactant protein A (SP-A), SP-B, and SP-C mRNA in alveolar type II cells of rats with lipopolysaccharide-induced (LPS-induced) lung injury. A small dose (1 to 2 mg/kg) of LPS was injected by intratracheal instillation in adult rats, and after a given period, the lungs were processed for examination using light and electron microscopy, for immunohistochemical study using anti-bromodeoxyuridine (anti-BrdU) and anti-SP-A antibodies, and for in situ hybridization using type-specific, surfactant cDNA probes. Northern blot analysis was also performed. From 3 to 7 days after LPS administration, alveolar septa were thickened, with increased numbers of epithelial and interstitial cells. BrdU-incorporated cells apparently increased in number in these areas, and many alveolar epithelial cells were intracellularly immunoreactive to anti-SP-A antibody, with many lamellar bodies found on examination using electron microscopy. By in situ hybridization, the number of autoradiographic silver grains for SP-A, SP-B, and SP-C mRNA increased strikingly, in alveolar type II epithelial cells of the lungs from LPS-administered rats. These responses of surfactant gene expression to LPS seemed to be stronger in alveolar epithelial cells than in the bronchiolar epithelium. By Northern blot analysis, the relative abundances of SP-A, SP-B, and SP-C mRNA were also higher in the LPS-administered lungs and correlated well with the results of in situ hybridization. The present study demonstrates that intratracheal administration of LPS induces the marked proliferation of alveolar epithelial cells in association with the concurrently increased SP-A, SP-B, and SP-C mRNA, as well as the SP-A production in the early response to lung injury. These results suggest that proliferation and differentiation of alveolar epithelial cells may play important roles in the repair process of the damaged alveoli after acute lung injury.

Animals↗

PubMed1996

Synthesis of a glioma-related ganglioside, O-Ac GM3 having 3-O-Ac ceramide and its substrate property toward hydrolases.

An O-acetyl group was selectively introduced into the ceramide moiety at the C-3-O on ganglioside GM3 containing N-acetyl neuraminic acid, the product of which has been previously found in rat glioma tissue as a glioma-associated ganglioside. The introduction of the acetyl residue involved a two-step process involving per O-acetylation of GM3 and saponification with a mild alkaline solution in a bilayer system constituted of water and water-immiscible organic solvent. Of the several solvents studied, 2-pentanol and diethyl ether gave the highest yields (68% and 62%, respectively). The chemical structure of the synthesized 3-O-acetyl GM3 was confirmed by proton nuclear magnetic resonance spectroscopy and fast atom bombardment-mass spectrometry, as well as by comparing the mobilities on thin-layer chromatography of its exoglycosidase-digested products with those of the synthesized, authentic 3-O-acetyl-lactosylceramide and ceramide. Furthermore, the substrate specificities of both 3-O-acetyl GM3 and 3-O-acetyl sphingomyelin toward exo- and endo-hydrolases were examined, revealing that they were hardly cleaved by the endoglycoceramidase and sphingolipid N-deacylase for the 3-O-acetyl GM3 and by sphingomyelinase for 3-O-acetyl sphingomyelin. Thus, the enzymes were found to recognize a free C-3 hydroxyl group on ceramide.

Acetylation↗

PubMed1996

[Surfactant protein A in bronchoalveolar lavage fluid from patients with idiopathic interstitial pneumonia].

We measured the levels of surfactant protein A (SP-A) in bronchoalveolar lavage fluid from patients with idiopathic interstitial pneumonia and from healthy volunteers. The SP-A levels in the patients who were smokers (1.4 +/- 0.2 micrograms/ml) were significantly (p < 0.05) lower than those in the patients who were nonsmokers (3.0 +/- 0.5 micrograms/ml). However, SP-A levels did not differ significantly between patients and volunteers who were smokers, or between patients and volunteers who were nonsmokers. The ratios of SP-A to phospholipid in patients who were smokers and in those who were non-smokers did not differ significantly from those in volunteers who were smokers and volunteers who were non smokers. The total number of alveolar macrophages in bronchoalveolar lavage fluid did not significantly correlate with the level of SP-A, although the percentage of alveolar macrophages correlated negatively (p < 0.05) with the level of SP-A. The low level of SP-A in patients with idiopathic interstitial pneumonia who are smokers may weaken the host defense functions in peripheral airways and may contribute to the poor outcomes in these patients.

Adult↗

PubMed1995

Ca(2+)-dependent binding of annexin IV to surfactant protein A and lamellar bodies in alveolar type II cells.

Surfactant protein A (SP-A), a lung-specific glycoprotein in pulmonary surfactant, is synthesized and secreted from the alveolar type II cells. It has been shown that SP-A is a Ca(2+)-binding protein with several binding sites and that the high-affinity site(s) is located in the C-terminal region of SP-A. In the present study we isolated the proteins from bovine lung soluble fraction that bind to SP-A in a Ca(2+)-dependent manner using DEAE-Sephacel and SP-A-conjugated Sepharose 4B. At least three different protein bands with molecular masses of 24.5, 32, and 33 kDa were observed on SDS/PAGE. The main protein, with molecular mass of 32 kDa, was identified as annexin IV by the partial-amino-acid-sequence analyses and an immunoblot analysis with anti-(annexin IV) antiserum. We also found from the immunoblot analysis that the cytosolic fraction of isolated rat alveolar type II cells contains annexin IV. In addition, when rat lung cytosol was loaded on to the lung lamellar body-conjugated Sepharose 4B in the presence of Ca2+, two proteins, with molecular masses of 32 and 60 kDa on SDS/PAGE respectively, were eluted with EGTA. The 32 kDa protein was shown to be annexin IV by an immunoblot analysis with the antiserum against annexin IV. The lung annexin IV augmented the Ca(2+)-induced aggregation of the lung lamellar bodies from rats. However, the augmentation of aggregation of the lung lamellar bodies by annexin IV was attenuated when the lamellar bodies were preincubated with polyclonal anti-SP-A antibodies. SP-A bound to annexin IV under conditions where contaminated lipid was removed. These results suggest that SP-A bound to annexin IV based on protein-protein interaction, though both proteins are phospholipid-binding proteins. All these findings suggest that the interaction between SP-A and annexin IV may have some role in alveolar type II cells.

Amino Acid Sequence↗

PubMed1995

Epitope mapping for monoclonal antibody against human surfactant protein A (SP-A) that alters receptor binding of SP-A and the SP-A-dependent regulation of phospholipid secretion by alveolar type II cells.

Surfactant protein A (SP-A) is a lung-specific glycoprotein in pulmonary surfactant and has a collagen like sequence on its N-terminal. SP-A has been shown to function as an inhibitor of phospholipid secretion by primary culture of alveolar type II cells via cell surface receptor(s) for SP-A. In a previous report, we showed that the C-terminal non-collagen like domain of human SP-A possessed the biological activities, and that a monoclonal antibody against human SP-A, PE10, abolished the biological activity of SP-A (Murata et al. (1993) Biochem. J. 291, 71-76). In the present study, we investigated an epitope of SP-A for PE10. Western blot analysis with fragmented peptides of human SP-A generated by both lysyl endopeptidase and BrCN showed that PE10 reacted with the peptide corresponding with Glu202 to the C-terminal but that it lacked the ability to bind to the peptide corresponding with Tyr208 to the C-terminal. The antibodies against a synthetic peptide (P1) corresponding with Glu202 to Asn217 of human SP-A inhibited the binding of PE10 to SP-A, suggesting that a similar site was recognized by both PE10 and anti-P1 antibodies. Anti-P1 antibodies as well as PE10 suppressed the biological activity of SP-A. A direct interaction between P1 and rat lung membranes, or between P1 and alveolar type II cell membranes was shown from the measurement of the fluorescence emission spectra of dansyl-labeled P1. These results suggest that an area contiguous to or near the region from Glu202 to Met207 of SP-A is important for expressing the biological activities.

Amino Acid Sequence↗

PubMed1995

Aberrant appearance of lung surfactant protein A in sera of patients with idiopathic pulmonary fibrosis and its clinical significance.

Pulmonary surfactant protein A (SP-A) is known to be a major phospholipid-associated glycoprotein in pulmonary surfactant, which is specific to the lung. In this study, the SP-A concentrations in sera of patients with various lung diseases were determined using an enzyme-linked immunosorbent assay. Patients with idiopathic pulmonary fibrosis (IPF) and pulmonary alveolar proteinosis (PAP) exhibited prominently high concentrations of serum SP-A compared to those of other lung diseases and healthy volunteers, although there were significant increases in serum SP-A concentrations in patients with pulmonary tuberculosis, chronic pulmonary emphysema, diffuse panbronchiolitis and bacterial pneumonia compared to those of healthy volunteers. Successive measurement in 2 patients with IPF showed that serum SP-A levels reflect the disease activity of IPF. In patients with IPF, serum SP-A concentrations were significantly correlated with those of serum lactate dehydrogenase, whereas there were no significant correlations of serum SP-A concentrations with erythrocyte sedimentation rate, arterial oxygen saturation, vital capacity and carbon monoxide diffusing capacity. Determination of serum SP-A will contribute to diagnosing IPF and PAP, and may reflect the disease activity of IPF.

Biomarkers↗

PubMed1995

Alveolar-to-vascular leakage of surfactant protein A in ventilated immature newborn rabbits.

We measured alveolar-to-vascular leakage of surfactant protein A (SP-A) in immature newborn rabbits delivered at a gestational age of 27 days. Experimental animals received, via a tracheal cannula, 2 ml/kg of a mixture of modified porcine surfactant (Curosurf, 80 mg/ml) and human recombinant SP-A (4 mg/ml). Littermate controls received the same volume of human SP-A in saline (4 mg/ml). After 30 min of artificial ventilation with a frequency of 40/min and an inspiration time of either 0.75 or 0.45 s, blood was sampled from the right ventricle and the lungs were lavaged. The content of human SP-A in serum and lung lavage fluid was determined with ELISA kits, and the alveolar-to-vascular leak expressed as the quotient of total SP-A in serum and lavage fluid. The leak in control animals amounted to about 2% of SP-A in lung wash and was several times higher in these animals than in those receiving surfactant. The leak was of the same order irrespective of whether the animals were ventilated with long or short inspiration time. We speculate that serum levels of SP-A may reflect the degree of lung injury in various forms of respiratory failure.

Animals↗

PubMed1995

Pulmonary surfactant protein D in sera and bronchoalveolar lavage fluids.

Pulmonary surfactant protein D (SP-D) is a hydrophilic glycoprotein with a reduced molecular mass of 43 kDa and a member of the C-type lectin superfamily, along with mannose-binding proteins and surfactant protein A (SP-A). We have recently prepared monoclonal antibodies against human SP-D and developed an enzyme-linked immunosorbent assay (ELISA). In this study, the levels of SP-D in sera and bronchoalveolar lavage (BAL) fluids of patients with lung diseases were determined by ELISA, using human recombinant SP-D as a standard. We demonstrated that the concentrations of SP-D in sera are prominently increased in patients with idiopathic pulmonary fibrosis (IPF), interstitial pneumonia with collagen disease (IPCD), and pulmonary alveolar proteinosis (PAP). Patients with IPF, IPCD, and PAP exhibited levels of serum SP-D 5.1-fold, 7.2-fold, and 7.0-fold, respectively, of those in healthy volunteers; 91.5% of the patients with IPF, 81.3% with IPCD, and 100% with PAP exhibited serum SP-D levels that exceeded the cut-off value (mean + 2 SD of control value). Serum SP-D levels appeared to reflect the disease activity of IPF and IPCD and the disease severity of PAP. High levels of SP-D in BAL fluids were shown in patients with PAP, but not with IPF and IPCD. We conclude that measurement of SP-D in sera can provide an easily identifiable and useful clinical marker for the diagnosis of IPF, IPCD, and PAP, and can predict the disease activity of IPF and IPCD and the disease severity of PAP.

Adult↗

PubMed1995

Pulmonary surfactant subfractions in patients with the acute respiratory distress syndrome.

Changes in the surfactant system have been observed in patients with acute respiratory distress syndrome (ARDS). These alterations in surfactant are thought to contribute to lung dysfunction in this disease. In this report we describe the changes in surfactant subfractions in bronchoalveolar wash obtained from five patients with established ARDS compared with five non-ARDS patients. Our results show that, in addition to the changes in surfactant composition and yield reported previously, the ratio of small to large surfactant aggregates is significantly increased in patients with ARDS compared with non-ARDS patients (0.48 +/- 0.09 versus 0.20 +/- 0.05 respectively [p < 0.05]). This increased ratio was associated with a decreased level of SP-A in the large aggregate fraction. We suggest that this increased ratio represents a marker for surfactant alterations in ARDS that is independent of lavage technique and can be measured in a very small surfactant sample.

Adult↗

PubMed1995

Lung surfactant protein-A and carcinoembryonic antigen in pleural effusions due to lung adenocarcinoma and malignant mesothelioma.

Lung surfactant protein-A (SP-A) is a major phospholipid-associated glycoprotein in surfactant, and is a useful immunohistochemical marker for lung adenocarcinoma. Carcinoembryonic antigen (CEA) has not been immunohistochemically detected in mesothelioma. In pleural effusions due to malignant mesothelioma, very low concentrations of SP-A and CEA can be expected. We studied the value of combined determinations of CEA and SP-A in pleural fluid to distinguish between lung adenocarcinoma and mesothelioma. SP-A and CEA concentrations were measured in pleural effusions from 78 patients with lung adenocarcinoma and 10 with malignant mesothelioma. SP-A concentrations in pleural effusions due to lung adenocarcinoma and mesothelioma were 516 +/- 140 and 16.9 +/- 3.6 ng.ml-1 (mean +/- SEM), respectively. CEA concentrations in pleural effusions due to lung adenocarcinoma and mesothelioma were 239 +/- 92.4 and 1.7 +/- 0.3 ng.ml-1, respectively. SP-A values did not exceed 100 ng.ml-1 in any of 10 mesotheliomas, whilst in 37 of 78 lung adenocarcinomas they did. CEA values did not exceed 10 ng.ml-1 in any of 10 mesotheliomas, whilst in 53 of 78 lung adenocarcinomas they did. Increased values of SP-A and/or CEA were found in pleural effusions from 67 of 78 lung adenocarcinomas. It is concluded that a combination of CEA and SP-A assays in pleural effusions will be helpful for discriminating lung adenocarcinoma from mesothelioma.

Adenocarcinoma↗

PubMed1995

Prenatal dexamethasone and exogenous surfactant therapy: surface activity and surfactant components in airway specimens.

To explain some of the effects of prenatal glucocorticoid treatment on lung function, surfactant parameters in the airway specimens of ventilator-dependent preterm infants were analyzed. In this double-blind study, the mothers of these infants had received dexamethasone (DEX) or placebo prenatally. Human surfactant was given for the treatment of moderate to severe respiratory distress syndrome. Seventy-six preterm infants with mean gestational age of 29 wk and mean birth weight of 1137 g were studied. The concentrations of surfactant components in epithelial lining fluid (ELF) were analyzed, and the surface activity was measured using a pulsating bubble method. Prenatal DEX treatment increased the responsiveness to exogenous surfactant and decreased the severity of respiratory failure during the first day of life. The treatment had no effect on the concentrations of surfactant phospholipids that were generally high. Prenatal DEX treatment increased the association between phospholipid concentration in ELF and the degree of respiratory failure. Prenatal DEX improved the surface activity of surfactant isolated from airway specimens and tended to increase the ratio of surfactant protein A to phosphatidylcholine among recipients of exogenous surfactant. A subgroup of infants, offspring of mothers with severe hypertension had an abnormally low concentration of surfactant protein A and a poor outcome, despite prenatal DEX treatment or surfactant substitution. Prenatal DEX decreased the concentration of nonsedimentable proteins in ELF and decreased the inhibition of surface activity by these proteins. Our results indicate that improved surfactant function during the first day of life explains some of the beneficial pulmonary effects of prenatal glucocorticoid treatment in preterm infants who are ventilator-dependent.

Apoproteins↗

PubMed1995

[Clinical significance of levels of lung surfactant protein A in serum, in various lung diseases].

To assess the utility of measuring lung surfactant protein A (SP-A) in serum, a newly developed SP-A kit (Teijin TDR-30) was used at four facilities to measure serum SP-A levels in patients with various lung diseases. Serum SP-A levels in healthy volunteers were 24.6 +/- 9.6 ng/ml (mean +/- SD). serum SP-A levels did not differ significantly between different age groups (thirties through seventies). A cut-off level of 43.8 ng/ml was calculated, based on the values of the healthy volunteers. The serum SP-A levels in patients with idiopathic interstitial pneumonia (IIP: 67.9 +/- 42.5 ng/ml), pulmonary alveolar proteinosis (PAP: 7.0 +/- 45.7 ng/ml), and collagen disease with interstitial pneumonia (CDIP: 55.3 +/- 37.9 ng/ml) were significantly higher than those in healthy volunteers. When calculated with the cut-off value stated above, the positive rate of diagnosis for IIP was 71.4%. SP-A levels correlated closely with the clinical course; SP-A levels rose significantly during exacerbations of IIP. Measurement of SP-A in serum is useful for the diagnosis of IIP, PAP, and CDIP, and for monitoring exacerbations of IIP.

Adult↗

PubMed1994

Enzyme-linked immunosorbent assay for human pulmonary surfactant protein D.

We developed a simple and sensitive enzyme-linked immunosorbent assay (ELISA) for human pulmonary surfactant protein D (SP-D). Human SP-D was purified from bronchoalveolar lavage fluids of patients with pulmonary alveolar proteinosis. Nine monoclonal antibodies (MAbs) were established from BALB/c mice immunized with the purified human SP-D. All MAbs were directed to either 43 kDa SP-D contained in lung lavage fluids of patients with pulmonary alveolar proteinosis or in amniotic fluids from healthy normal pregnancies. The ELISA is based on a sandwich method using two MAbs, 6B2 and 7C6. Cross-reactivity to human SP-A or rat SP-D was evaluated as below 0.6%. The recovery of different concentrations of SP-D ranged from 94.4% to 111.2%, and serial dilutions of amniotic fluids showed good linearity. SP-D concentrations in 21 amniotic fluids from normal pregnancies were measured by the ELISA. The mean concentration in amniotic fluids from pregnancies in the third trimester was significantly higher than that from earlier stages of gestation (p < 0.001), indicating that this ELISA may be applicable for prediction of fetal lung maturity.

Amniotic Fluid↗

PubMed1994

Effects of carboxyl methylation of photoreceptor G protein gamma-subunit in visual transduction.

G protein gamma-subunits are isoprenylated and carboxyl-methylated at the C-terminal cysteine, which is indispensable for the function of photoreceptor G protein transducin (T alpha beta gamma). However, the physiological role of the methylation and its reversibility have been unclear. Here we isolated methylated and non-methylated forms of farnesylated T beta gamma, and demonstrated that the methylation remarkably facilitates not only the membrane association of T beta gamma but also the subunit interaction between T alpha and T beta gamma. Consequently, the functional coupling of transducin with light-activated receptor, metarhodopsin II, was stabilized by the methylation, resulting in acceleration of GTP gamma S (guanosine 5'-3-O-(thio) triphosphate) binding to T alpha. An examination of the reversibility of the methylation suggested that T gamma is kept fully methylated in rod outer segments. These observations indicate that the methylation of T gamma plays an important role in the most efficient photon-signal transduction process in rod cells.

Adenosine Diphosphate Ribose↗

PubMed1994

Vascularized bone allografts: review of current concepts.

Advances in the field of microsurgery over the past two decades, together with the discovery of a powerful immunosuppressive, cyclosporin A, have brought vascularized osteochondral allografts closer to reality. In this review, the authors describe the history of laboratory research on vascularized osteochondral allografts using immunosuppression, as well as their experimental and preliminary clinical experiences.

Animals↗

PubMed1993

Different functional forms of G-protein beta gamma-subunits, beta gamma-I and beta gamma-II, in bovine brain.

Heterotrimeric GTP binding regulatory proteins (G proteins) are involved in the signal transduction process in cells. We have previously demonstrated that G protein (Gi/o) in bovine brain contains two subspecies of the beta gamma-subunit, beta gamma-I and beta gamma-II, with distinct gamma subunits, i.e., gamma-I and gamma-II, but identical beta-subunit. We found that gamma-I agreed with the gamma-subunit reported elsewhere, while gamma-II was a novel gamma-subunit. In the present study we separated the fractions containing G-protein isoforms, Go*, Gi1, Go and Gi2, with a Mono Q column and they were subjected to 15% polyacrylamide gel electrophoresis. All isoforms were shown to possess both gamma subunits, gamma-I and gamma-II. The molar ratio of the two gamma-subunit isoforms was one to one, based on the relative intensity of Coomassie blue-stained bands. Differences in biological activity between G proteins composed of beta gamma-I and beta gamma-II were investigated. The amount of GTP gamma S bound to the alpha-subunit was larger in alpha beta gamma-I than in alpha beta gamma-II. The pertussis toxin-catalyzed ADP-ribosylation on alpha-subunit was enhanced by either beta gamma-subunit subspecies, but the effect was larger with beta gamma-I than with beta gamma-II. From gel filtration with a Sephacryl S 300, it appeared that all alpha- and either beta gamma-subunit, i.e., beta gamma-I or beta gamma-II, formed a trimer complex. These findings suggest the possible existence of two different functional forms in each G-protein isoform depending on the beta gamma-subunit subspecies.

Animals↗