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Y Kuroki

Publications and source records attributed to Y Kuroki.

At least 127 records · Page 7Linked to original sources
PubMed1996

Limulus intracellular coagulation inhibitor type 3. Purification, characterization, cDNA cloning, and tissue localization.

We reported that limulus intracellular coagulation inhibitor type-1 (LICI-1) (Miura, Y., Kawabata, S., and Iwanaga, S. (1994) J. Biol. Chem. 269, 542-547) and LICI type-2 (LICI-2) (Miura, Y., Kawabata, S. , Wakamiya, Y., Nakamura, T., and Iwanaga, S. (1995) J. Biol. Chem. 270, 558-565) found in the hemocyte lysate belong to the serpin family. The LICI-1 specifically inhibits limulus lipopolysaccharide-sensitive serine protease, factor C (k1 = 2.5 x 10(6) M-1 s-1), whereas LICI-2 inhibits preferentially limulus clotting enzyme (k1 = 4.3 x 10(5) M-1 s-1). In our ongoing studies on limulus serpin, we found another inhibitor, named LICI type-3 (LICI-3), which strongly inhibits (1,3)-beta-D-glucan-sensitive serine protease, factor G (k1 = 3.9 x 10(5) M-1 s-1). Thus, the limulus hemolymph coagulation cascade is effectively regulated by at least the three endogenous serpins. LICI-3, newly identified in hemocytes, is a single chain glycoprotein with an apparent Mr = 53,000, the largest one among known limulus serpins. A cDNA sequence for LICI-3 coded a mature protein of 392 amino acids, of which 68 residues were confirmed by peptide sequencing. LICI-3 showed significant sequence similarity to LICI-1 (45.8% identity) and LICI-2 (33.7% identity). LICI-3 contained a putative reactive site, -Arg-Ser-, distinct from that of LICI-2 (-Lys-Ser-) but the same as that of LICI-1. Expression of LICI-3 mRNA was detected only in hemocytes, and not in heart, brain, stomach, intestine, coxal gland, and skeletal muscle. Immunoblotting of the hemocyte-derived large and small granules with antiserum against LICI-3 suggested that it is stored specifically in large granules, as in the case of LICI-1 and LICI-2, and is released in response to external stimuli.

Amino Acid Sequence↗
PubMed1996

Human surfactant protein A with two distinct oligomeric structures which exhibit different capacities to interact with alveolar type II cells.

The lung lavage fluids from patients with pulmonary alveolar proteinosis have been generally used as a source for human surfactant protein A (SP-A). We have recently found that a multimerized form of SP-A oligomer (alveolar proteinosis protein-I, APP-I) exists besides the normal-sized octadecamer (APP-II) in SP-As isolated from the patients. When analysed by Bio-Gel A15m column chromatography in 5 mM Tris buffer (pH 7.4), the apparent molecular masses of APP-I and APP-II were 1.65 MDa and 0.93 MDa, respectively. Gel-filtration analysis also revealed that APP-II is clearly separated from APP-I in the presence of 2 mM Ca2+ and 150 mM NaCI. We investigated the abilities of both SP-A oligomers to regulate phospholipid secretion and to bind to alveolar type II cells. Although APP-I inhibited lipid secretion, it was clearly a less effective inhibitor than APP-II. IC50 for inhibition of lipid secretion was apparently 0.23 +/- 0.08 microgram/ml (0.14 +/- 0.05 nM) and 0.055 +/- 0.019 microgram/ml (0.059 +/- 0.020 nM) for APP-I and APP-II, respectively. Both proteins bound to monolayers of type II cells in a concentration-dependent manner; however, APP-I clearly had a lower affinity to bind to type II cells. The apparent dissociation contants were, K(d) = 2.31 +/- 0.70 microgram/ml (1.40 +/- 0.43 nM) and 0.89 +/- 0.22 microgram/ml (0.95 +/- 0.24 nM) for APP-I and APP-II, respectively. Excess unlabelled rat SP-A replaced 45% of 125I-APP-I and 77% of 125I-APP-II for type II cell binding. Although 125I-APP-II competed with excess unlabelled APP-I or APP-II, 125I-APP-I failed to compete and instead its binding rather increased in the presence of unlabelled APPs. The biotinylated APP-I bound to APP-I and APP-II coated on to microtitre wells in a concentration-dependent manner, indicating that APP-I interacts with APPs. This study demonstrates that the multimerized form of human SP-A oligomer exhibits the following attributes: (1) the reduced capacity to regulate phospholipid secretion from type II cells, and (2) lower affinity to bind to type II cells, and that the integrity of a flower-bouquet-like octadecameric structure of SP-A oligomer is important for the expression of full activity of this protein, indicating the importance of the oligomeric structure of mammalian lectins with collagenous domains.

Animals↗
PubMed1996

Interaction of phospholipid liposomes with plasma membrane isolated from alveolar type II cells: effect of pulmonary surfactant protein A.

Pulmonary surfactant protein A (SP-A) augments the uptake of phospholipid liposomes containing dipalmitoylphosphatidylcholine (DPPC) by alveolar type II cells. The SP-A-mediated uptake process of lipids by type II cells have not been well understood. In the present study we investigated the SP-A-mediated interaction of phospholipids with plasma membrane isolated from alveolar type II cells. SP-A increased the amount of liposomes containing radiolabeled DPPC associated with type II cell plasma membrane by 4-fold compared to the control without SP-A when analyzed by sucrose density gradient centrifugation. This effect is dependent upon the SP-A concentration. The enhancement was inhibited by anti-SP-A antibody and EGTA. When type II cell plasma membrane and liposomes containing [14C]DPPC and [3H]triolein were coincubated with or without SP-A, analysis on sucrose density gradients revealed that the profiles of [14C]DPPC and [3H]triolein in each fraction were almost identical with or without SP-A, indicating that SP-A mediates the binding of liposomes to plasma membrane but not transfer of DPPC. SP-A increased the association of liposomes containing DPPC with the membrane by 2-fold more than that containing 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC). SP-A induced aggregation of phospholipid liposomes containing PLPC as well as those containing DPPC, but the final turbidity of DPPC liposomes aggregated by SP-A was only by 15% greater than that of PLPC liposomes. The amount of DPPC liposomes associated with the plasma membrane derived from type II cells was 2-fold greater than that from liver. We speculate that the SP-A-mediated interaction of lipids with type II cell plasma membrane may contribute, in part, to the lipid uptake process by type II cells.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

A human protective protein gene partially overlaps the gene encoding phospholipid transfer protein on the complementary strand of DNA.

The entire human protective protein gene has been cloned, and structural analysis revealed that the gene spans 7.5kb and comprises 15 exons. Furthermore, it partially overlaps on the opposite strand with the gene encoding phospholipid transfer protein. This region of DNA on chromosome 20 appears to encode two distinct mRNAs expressing defined functional products, and the mRNAs overlap by 58 nucleotides at their 3'-untranslated ends.

Alternative Splicing↗
PubMed1996

Mucopolysaccharidosis IVA: submicroscopic deletion of 16q24.3 and a novel R386C mutation of N-acetylgalactosamine-6-sulfate sulfatase gene in a classical Morquio disease.

The N-acetylgalactosamine-6-sulfate sulfatase (GALNS) gene, which is responsible for autosomal recessive mucopolysaccharidosis IVA (MPSIVA), has been assigned to the long arm of chromosome 16, subregion 24.3, an area where the adenine phosophoribosyltransferase (APRT) gene and renal dipeptidase (DPEP I) gene are also localized. Molecular genetic studies on a severely affected patient with MPSIVA (Morquio disease), without karyotypic abnormality, revealed a partial submicroscopic deletion of 16q24.3 and a single point mutation on the other allele, with no functional GALNS activity. The patient, his mother, and siblings were hemizygous for GALNS and APRT loci, evidenced by informative RFLP and gene dosage analyses combined with a fluorescence in situ hybridization, utilizing a partial genomic clone of GALNS, but heterozygosity was retained at the DPEP I locus and proximal D16S7. Haplotyping of the family members revealed recombinational events between DPEP I locus and three other polymorphic loci on the paternal chromosome, localizing GALNS gene on the proximal side to DPEP I gene. As estimated from the genetic distance between two flanking markers of proximal D16S7 and distal DPEP I locus, size of the deletion was less than 3Mb. Mother of the boy and two older siblings were asymptomatic, despite this interstitial deletion of the Giemsa-light G band. The remaining paternal allele had no gene rearrangement but GALNS activity was not encoded as Arginine at 386 was replaced with Cysteine (R386C), suggesting this alteration accounts for the severe phenotype. Allelic loss of APRT is frequently observed in cancer tissues, thereby suggesting that the tumor suppressor gene locates near the APRT locus. No family member has evidence of any malignant disease. This study is apparently the first documentation of interstitial deletion of 16q24.3, involving GALNS and APRT genes.

Adenine Phosphoribosyltransferase↗
PubMed1996

Revascularization in nontraumatic osteonecrosis of the femoral head.

To study the revascularization pattern of nontraumatic osteonecrosis, superselective angiography of the femoral medical circumflex artery was done twice on 13 hips for which no treatment had been given. Angiographic evaluation of the hips with early-stage osteonecrosis not visible on radiographs showed the absence of superior retinacular arteries from the stump in all hips. Penetration of small vessels was seen on 6 hips. Bony scintigraphy of 13 hips and magnetic resonance imaging of 9 hips were taken at about the same time. Bony scintigraphy and magnetic resonance imaging results were positive in 11 of 13 hips and in all 9 hips, respectively. The patients were observed until evidence of necrosis appeared on radiographs. When this sign became evident, a second angiography was conducted, which indicated the penetration of erratically formed vessels with increase in size in 12 hips. It was assumed that the blood supply from the superior retinacular arteries was interfered with in large areas of the femoral head and that revascularization started with the formation of small vessels, followed by further penetration of large vessels.

Adolescent↗
PubMed1996

Femoral deformity in adults with developmental hip dysplasia.

Quantitative computed tomography and 3 dimensional modeling were used to portray the deformity of the proximal femur in 24 Japanese adults with low subluxations to high dislocations secondary to developmental dysplasia of the hip. Periosteal and canal bony contours were extracted, 3 dimensional models generated, and morphologic parameters were calculated for each femur. Three dimensional illustrations of the average deformity and variability were created. Morphologic parameters were not found to be statistically correlated with the degree of the disease. Interestingly, the major axis of the canal contours of the proximal femur was found to be aligned with the plane of the femoral neck (anteversion), regardless of the degree of anteversion. Thus, the amount of version correctable in an uncemented prosthesis is limited, and at times may require a special prosthesis, overreaming, undersizing and cementing, or an osteotomy. Additionally, the proximal medial curvature of the dysplastic femurs was straighter than that of normal femurs. This necessitated a corresponding reduction in the proximal medial curvature of a conventional uncemented prosthesis to match the medial curvature of the individual femur and the average developmentally dysplastic femur. This objective description of the developmentally dysplastic femur corroborates clinical observations, highlights some unrecognized findings, provides a rationale for planning reconstructions, and aids in the design of prostheses for adult patients with this deformity.

Adult↗
PubMed1996

Currarino triad with a terminal deletion 7q35-->qter.

We describe a de novo terminal deletion of the long arm of chromosome 7 in a 5 year old girl with the Currarino triad, characterised by congenital anorectal stenosis, a sacral defect, and a presacral mass. Recently, this autosomal dominant trait has been shown to be linked to 7q36, the same region as holoprosencephaly (HPE3). The cytogenetic findings in the present patient with the Currarino triad provided further evidence that a gene(s) for the Currarino triad is located in the 7 q terminal segment.

Abnormalities, Multiple↗
PubMed1996

The Y chromosome region essential for spermatogenesis.

We analyzed DNA from 153 Japanese men with azoospermia or severe oligozoospermia whose Y chromosomes were cytogenetically normal. A total of 23 loci on the Y chromosome were examined: 15 loci within interval 6 including YRRM1 and DAZ, and 8 loci outside interval 6. Microdeletions were observed in 20 individuals. All deletions involved at least one locus within interval 6. The YRRM1 gene deletion was found in 4 patients, of whom 2 also lacked the SMCY gene. The remaining 16 individuals shared the absence of 10 loci between DYS7C and DYS239 including the DAZ gene. Among them, 13 were azoospermic while 3 showed a little sperm production, indicating that the common deletion resulted in phenotypic diversity. Since there is no region commonly deleted in all patients, azoospermia caused by deletion of the Y chromosome long arm may be genetically heterogeneous.

Adult↗
PubMed1996

Lipid analysis and surfactant-associated protein expression in lung adenocarcinoma cells from pleural effusion.

Primary lung adenocarcinomas originate from the progenitor cells of peripheral airway cells. Alveolar type II cells and Clara cells are the major progenitor cells of peripheral airway cells. Alveolar type II cells produce a lipid-protein complex called surfactant, which contains surfactant proteins SP-A, SP-B, SP-C and SP-D. Phosphatidylcholine (PC) and phosphatidylglycerol (PG) are believed to be essential for the surfactant function. Clara cells also express SP-A, SP-B and SP-D but not SP-C. In this study we examined the properties of the cancer cells isolated from the pleural effusion of a patient with primary lung adenocarcinoma by analyzing lipids, proteins and mRNAs. The cancer cells, designated as LC117 cells, were isolated from the pleural effusion of a patient with primary lung adenocarcinoma. The percent distributions of [14C]-acetate incorporated into PC and PG in the cancer cells were 55.7 and 1.1%, respectively. The disaturated species in total PC was 46.2%. Immunoblotting analysis using anti-SP-D monoclonal antibody revealed that the pleural effusion from a patient with lung adenocarcinoma contained SP-D. We determined the concentrations of SP-A and SP-D by enzyme-linked immunosorbent assay. The pleural effusions from this patient and the media incubated with cancer cells exhibited significant levels of SP-D as well as SP-A. Reverse transcriptase-polymerase chain reaction demonstrated that the tumor cells expressed mRNAs for SP-C as well as the other surfactant proteins. The results demonstrate that tumor cells from lung adenocarcinoma express all of surfactant-associated proteins, indicating that LC117 cells originate from alveolar type II cells. This study indicates that the combination of analyses of lipids, proteins and mRNAs in the cancer cells isolated from pleural effusion is useful to understand the property of lung adenocarcinoma.

Adenocarcinoma↗
PubMed1996

Surfactant protein A accumulating in the alveoli of patients with pulmonary alveolar proteinosis: oligomeric structure and interaction with lipids.

Pulmonary alveolar proteinosis (PAP) is a diffuse lung disease of unknown etiology in which the alveoli and terminal bronchioles of the lung fill with large amounts of surfactant-rich lipoproteinaceous materials. Its major pathologic manifestations are a small number of normal tubular myelin structures and an unusual abundance of multilamellated structures. Since surfactant protein A (SP-A) plays an important role in surfactant phospholipid homeostasis, we investigated the structural features of SP-A oligomers (alveolar proteinosis protein, APP) accumulating in the alveoli of individuals with PAP, and examined the abilities of APP to interact with lipids. Analysis of APP by Bio Gel A15m column chromatography revealed that it was composed of two protein peaks, one of which (APP-I) eluted at the position near that of blue dextran whereas the other (APP-II) eluted far behind blue dextran but ahead of thyroglobulin. These populations of APP showed almost identical amino acid compositions. Electron microscopic observations of APP molecules using the rotary shadow technique revealed that APP-II was observed as hexameric particles, presumably consisting mainly of octadecamers whose diameter was approximately 30 nm. The population seen for APP-II was similar to that seen for SP-A from healthy individuals. In contrast, APP-I was observed as multimerized larger aggregates whose diameter appeared to be about 70 to 90 nm. Both APP-I and APP-II retained the abilities to bind dipalmitoylphosphatidylcholine (DPPC). They also induced phospholipid vesicle aggregation in a concentration-dependent manner. The maximal turbidity for light scattering induced by APP-I and APP-II was almost equivalent when analyzed as a function of molar concentration. In vitro reconstitution experiments with porcine surfactant protein B (SP-B) and phospholipids revealed that the multilamellated membranes in structures formed from APP-I consisted of several layers of doubled unit membranes. APP-I failed to form tubular myelin structures. In contrast, APP-II formed well-formed lattice structures seen in tubular myelin. From these data we conclude that there exists an abnormal multimerized form of SP-A oligomer in the alveoli of patients with PAP, and that this unusual subpopulation of SP-A oligomer exhibits abnormal function on phospholipid membrane organization.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Decreased contents of surfactant proteins A and D in BAL fluids of healthy smokers.

Hydrophilic surfactant proteins, surfactant protein A (SP-A) and surfactant protein D (SP-D), have important roles in modulating the host defense functions in the peripheral airways. It has been reported that cigarette smoke may alter the component and function of pulmonary surfactant. In this study, we determined the contents of SP-A and SP-D in BAL fluids of healthy smokers and nonsmokers by enzyme-linked immunosorbent assay using monoclonal antibodies against each protein. The contents of SP-A and SP-D in BAL fluids were significantly (p<0.05) decreased in smokers compared to those in nonsmokers, although there was no significant difference of total phospholipid content between smokers and nonsmokers. These results suggest that the decreased levels of SP-A and SP-D in smokers may impair the host defense functions of surfactant in the peripheral airways and might have a crucial roles in the development of chronic obstructive lung disease.

Adolescent↗
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

[Recent advances in molecular biology with respect to pulmonary surfactant apoproteins].

Pulmonary surfactant is a complex mixture of lipids and proteins that functions to keep alveoli from collapsing at the end of expiration. Dipalmitoylphosphatidylcholine has been identified as the most important component for lowering surface tension at the air-liquid interface. Hydrophobic surfactant apoproteins, SP-B and SP-C, play essential roles in the biophysical functions of the surfactant phospholipids. Hydrophilic surfactant apoproteins (SP-A and SP-D) that are members of C-type lectin superfamily, interact with phospholipids and glycolipids and modulate host defense functions in the lung. SP-A also plays an important role in regulating phospholipid homeostasis in the alveolar spaces. Recent advances in genetics and molecular biology have clarified the structure-function relationship of surfactant apoproteins.

Amino Acid Sequence↗
PubMed1996

Human peroxisome assembly factor-2 (PAF-2): a gene responsible for group C peroxisome biogenesis disorder in humans.

Peroxisome-biogenesis disorders (PBD) are genetically heterogeneous and can be classified into at least ten complementation groups. We recently isolated the cDNA for rat peroxisome assembly factor-2 (PAF-2) by functional complementation using the peroxisome-deficient Chinese-hamster-ovary cell mutant, ZP92. To clarify the novel pathogenic gene of PBD, we cloned the full-length human PAF-2 cDNA that morphologically and biochemically restores peroxisomes of group C Zellweger fibroblasts (the same as group 4 in the Kennedy-Krieger Institute) and identified two pathogenic mutations in the PAF-2 gene in two patients with group C Zellweger syndrome. The 2,940-bp open reading frame of the human PAF-2 cDNA encodes a 980-amino-acid protein that shows 87.1% identity with rat PAF-2 and also restored the peroxisome assembly after gene transfer to fibroblasts of group C patients. Direct sequencing of the PAF-2 gene revealed a homozygous 1-bp insertion at nucleotide 511 (511 insT) in one patient with group C Zellweger syndrome (ZS), which introduces a premature termination codon in the PAF-2 gene, and, in the second patient, revealed a splice-site mutation in intron 3 (IVS3+1G-->A), which skipped exon 3, an event that leads to peroxisome deficiency. Chromosome mapping utilizing FISH indicates that PAF-2 is located on chromosome 6p21.1. These results confirm that human PAF-2 cDNA restores peroxisome of group C cells and that defects in the PAF-2 produce peroxisome deficiency of group C PBD.

ATPases Associated with Diverse Cellular Activitie↗
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

Miller-Dieker syndrome due to maternal cryptic translocation t(10;17) (q26.3;p13.3)

We report on a 3-month-old girl with Miller-Dieker syndrome resulting from a maternal full-cryptic translocation t(10;17) (q26.3;p13.3) detectable only by using fluorescence in situ hybridization (FISH). Parental studies using FISH are crucial for genetic counselling in cases of Miller-Dieker syndrome with submicroscopic deletion at 17p13.3. In a family with a parental cryptic translocation and high recurrence risk, parental diagnosis using FISH is feasible.

Abnormalities, Multiple↗