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Biomedical subjects

Y Kuroki

Publications and source records attributed to Y Kuroki.

At least 73 records · Page 4Linked to original sources

Exclusion of linkage of Shwachman-Diamond syndrome to chromosome regions 6q and 12q implicated by a de novo translocation.

Shwachman-Diamond syndrome is a rare genetic disorder of unknown pathogenesis involving exocrine pancreatic insufficiency and hematological and skeletal abnormalities. There is broad clinical variability; the extent of heterogeneity is unknown but comparisons within a large cohort of patients show no striking differences between patients of families with single or multiple affected offspring. Segregation analysis of a cohort of 69 families has suggested an autosomal recessive mode of inheritance. A single constitutional de novo chromosome rearrangement was reported in a Japanese patient involving a balanced translocation, t(6;12)(q16.2;q21.2), thereby suggesting possible loci for a genetic defect. Evenly spaced microsatellite markers spanning 26-32 cM intervals from D6S1056 to D6S304 and D12S375 to D12S346 were analyzed for linkage in members of 13 Shwachman-Diamond syndrome families with two or three affected children. Two-point lod scores were calculated for each marker under assumptions of recessive inheritance and complete penetrance. Negative lod scores indicated exclusion of both chromosome regions. Further, affected sibs were discordant for inheritance of chromosomes in most families based on constructed haplotypes. The cytogenetic abnormality is not associated with most cases of Shwachman-Diamond syndrome.

Bone and Bones↗

Characterization of the Ca2+-dependent binding of annexin IV to surfactant protein A.

We have shown previously that surfactant protein A (SP-A) binds to annexin IV in a Ca2+-dependent manner [Sohma, Matsushima, Watanabe, Hattori, Kuroki and Akino (1995) Biochem. J. 312, 175-181]. Annexin IV is a member of the annexin family having four consensus repeats of about 70 amino acids and a unique N-terminal tail. In the present study, the functional site of both annexin IV and SP-A for the Ca2+-dependent binding was investigated using mutant proteins. SP-A bound in a Ca2+-dependent manner to an annexin-IV truncation mutant consisting of the N-terminal domain and the first three domains (T(N-1-2-3)). SP-A also bound to T3-4, but this interaction was not Ca2+-dependent. SP-A bound weakly to the other truncation mutants (T(N-1-2), T(2-3) and T(2-3-4)). Each consensus repeat of annexin IV possesses a conserved acidic amino acid residue (Glu70, Asp142, Glu226 and Asp301) that putatively ligates Ca2+. Using annexin-IV DE mutants in which one, two or three residues out of the four Asp/Glu were altered to Ala by site-directed mutagenesis [Nelson and Creutz (1995) Biochemistry 34, 3121-3132], it was revealed that Ca2+ binding in the third domain is more important than in the other Ca2+-binding sites. SP-A is a member of the animal lectin group homologous with mannose-binding protein A. The substitution of Arg197 of rat SP-A with Asp or Asn eliminated binding to annexin IV, whereas the substitution of Glu195 with Gln was silent. These results suggest that the Ca2+ binding to domain 3 of annexin IV is required for the Ca2+-dependent binding by SP-A and that Arg197 of SP-A is important in this binding.

Animals↗

Pulmonary surfactant protein A modulates the cellular response to smooth and rough lipopolysaccharides by interaction with CD14.

Pulmonary surfactant protein A (SP-A) plays an important part in Ab-independent host defense mechanisms of the lung. In this study we investigated how SP-A interacts with distinct serotypes of bacterial LPS and modulates LPS-elicited cellular responses. SP-A bound to rough forms but not to smooth forms of LPS. In the macrophage-like cell line U937, SP-A inhibited mRNA expression and secretion of TNF-alpha induced by smooth LPS, but rough LPS-induced TNF-alpha expression was unaffected by SP-A. When U937 cells and rat alveolar macrophages were preincubated with SP-A, smooth LPS failed to induce TNF-alpha secretion, whereas rough LPS-induced TNF-alpha secretion was modestly increased. To clarify the mechanism by which SP-A modulates LPS-elicited cellular responses, we further examined the interaction of SP-A with CD14, which is known as a major LPS receptor. Western blot analysis revealed that CD14 was one of the SP-A binding proteins isolated from solubilized U937 cells. In addition, SP-A directly bound to recombinant soluble CD14 (rsCD14). When rsCD14 was preincubated with SP-A, the binding of rsCD14 to smooth LPS was significantly reduced but the association of rsCD14 with rough LPS was augmented. These results demonstrate the different actions of SP-A upon distinct serotypes of LPS and indicate that the direct interaction of SP-A with CD14 constitutes a likely mechanism by which SP-A modulates LPS-elicited cellular responses.

Animals↗

Introduction of mannose binding protein-type phosphatidylinositol recognition into pulmonary surfactant protein A.

Pulmonary surfactant protein A (SP-A) and mannose-binding protein A (MBP-A) are collectins in the C-type lectin superfamily. These collectins exhibit unique lipid binding properties. SP-A binds to dipalmitoyl phosphatidylcholine (DPPC) and galactosylceramide (GalCer) and MBP-A binds to phosphatidylinositol (PI). SP-A also interacts with alveolar type II cells. Monoclonal antibodies (mAbs PE10 and PC6) that recognize human SP-A inhibit the interactions of SP-A with lipids and alveolar type II cells. We mapped the epitopes for anti-human SP-A mAbs by a phage display peptide library. Phage selected by mAbs displayed the consensus peptide sequences that are nearly identical to 184TPVNYTNWYRG194 of human SP-A. The synthetic peptide GTPVNYTNWYRG completely blocked the binding of mAbs to human SP-A. Chimeric proteins were generated in which the rat SP-A region Thr174-Gly194 or the human SP-A region Ser174-Gly194 was replaced with the MBP-A region Thr164-Asp184 (rat ama4 or hu ama4, respectively). The mAbs failed to bind hu ama4. Rat ama4 bound to an affinity matrix on mannose-sepharose but lost all of the SP-A functions except carbohydrate binding and Ca2+-independent GalCer binding. Strikingly, the rat ama4 chimera acquired the PI binding property that MBP-A exhibits. This study demonstrates that the amino acid residues 174-194 of SP-A and the corresponding region of MBP-A are critical for SP-A-type II cell interaction and Ca2+-dependent lipid binding of collectins.

Animals↗

Young-Simpson syndrome: further delineation of a distinct syndrome with congenital hypothyroidism, congenital heart defects, facial dysmorphism, and mental retardation.

Young-Simpson syndrome is a rare congenital disorder, characterized by congenital hypothyroidism, congenital heart defects, facial dysmorphism, cryptorchidism in males, hypotonia, mental retardation, and postnatal growth retardation. We describe the cases of a 5-year-old boy and a 7-year-old girl with a similar constellation of symptoms and compared them with previously reported patients.

Brain↗

Noonan syndrome and cavernous hemangioma of the brain.

We present two patients with multiple characteristics that occur in Noonan phenotype and cavernous hemangioma of the brain. The first patient, who had been diagnosed radiographically as having a cavernous hemangioma in the left basal ganglia at age 15 years, developed massive intracerebral hemorrhage, resulting in sudden death at home at 19 years. The second patient, who was diagnosed radiographically as having a cavernous hemangioma in the left parietal lobe at age 17 years, is being followed carefully (the patient is currently 18 years old). A review disclosed four cases of structural cerebrovascular abnormalities with or without subsequent hemorrhage. Neither these four patients nor our two patients had any severe anomalies in the heart or large vessels, which are frequently seen in patients with Noonan syndrome. Cerebrovascular abnormalities might have a significant influence on the prognosis of patients with Noonan syndrome, especially those having no severe abnormalities in the heart or large vessels.

Adolescent↗

Pancreatoduodenectomy for locally advanced or recurrent colon cancer: report of two cases.

A 66-year-old man, who had ascending colon cancer which invaded the duodenum, pancreas, and superior mesenteric vein, underwent a curative resection including an extended right hemicolectomy, pylorus-preserving pancreatoduodenectomy, and a partial resection of the superior mesenteric vein. The pathological examination revealed adenocarcinoma of the colon, which directly invaded the duodenum and pancreas, thus causing duodenocolic fistula. Tumor infiltration to the superior mesenteric vein was not histologically proven. Two out of 40 lymph nodes were also involved. The patient is still alive and disease-free 37 months after the operation. A 72-year-old man, with a history of surgery two previous times for ascending colon cancer and its recurrence, underwent a third operation including a resection of the former ileocolic anastomosis en bloc by means of a pylorus-preserving pancreatoduodenectomy with a curative intent. The pathological examination revealed adenocarcinoma of the colon, which directly invaded the duodenum and pancreas. Seven out of 31 lymph nodes were also involved. The patient died of recurrence 24 months after the third operation. These two cases demonstrated the usefulness of a resection of the colon en bloc by means of a pancreatoduodenectomy in patients with either locally advanced colon cancer or locally advanced recurrent colon cancer.

Adenocarcinoma↗

Chromosome painting of Y chromosomes and isolation of a Y chromosome-specific repetitive sequence in the dioecious plant Rumex acetosa.

The dioecious plant Rumex acetosa has a multiple sex chromosome system: XX in female and XY(1)Y(2) in male. Both types of Y chromosome were isolated from chromosome spreads of males by manual microdissection, and their chromosomal DNA was amplified using degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR). When the biotin-labeled DOP-PCR product was hybridized with competitor DNA in situ, the fluorescent signal painted the Y chromosomes. A library of Y chromosome DNA was constructed from the DOP-PCR product and screened for DNA sequences specific to the Y chromosome. One Y chromosome-specific DNA sequence was identified and designated RAYSI (R. acetosa Y chromosome-specific sequence I). RAYSI is a tandemly arranged repetitive DNA sequence that maps to the 4',6-diamidino-2-phenylindole bands of both Y chromosomes.

Base Sequence↗

Pulmonary alveolar proteinosis in infants.

UNLABELLED: We investigated the histological and molecular characteristics of pulmonary alveolar proteinosis (PAP) in two siblings (a brother and sister) who did not exhibit respiratory distress at birth but who each developed symptoms during infancy. Histological analysis of lung specimens showed positive staining for surfactant proteins in both patients. The polymerase chain reaction revealed expression of messenger RNA for surfactant protein B (SP-B) in the lung specimens. No defect in SP-B which is characteristic of the congenital form of PAP was observed. The concentration of surfactant protein A (SP-A) in bronchial alveolar lavage (BAL) fluid was elevated in patient 1 suggesting the BAL concentration of SP-A may be a clue to the diagnosis of this form of PAP. CONCLUSION: The accumulation of surfactant protein A in two siblings with an infantile form of pulmonary alveolar proteinosis could be a clue to the diagnosis.

Biopsy↗

Genetic variations on the Y chromosome in the Japanese population and implications for modern human Y chromosome lineage.

A polymorphism in the coding sequence of the SRY gene was found by single-strand conformation polymorphism (SSCP) and direct sequencing analysis. The new allele of the SRY gene, which is raised by a C-to-T transition in the 155th codon, was found in 24% of Honshu, 35% of Okinawan, and 51% of Korean males respectively, whereas it was not observed among 16 Caucasian and 18 Negroid males. A haplotype analysis of the Y chromosome was carried out in Japanese, Korean, Caucasian and Negroid populations, using a combination of the polymorphisms in SRY, DXYS5Y, DYS287, and DXYS241Y loci. The results indicated that the Y chromosomes can be classified into seven heplotypes (Ia, Ib, Ic, IIa, IIb, III, IV). However, of these seven, only four (Ia, IIa, III, IV) were observed in the Japanese population. Furthermore, the presumed haplotype C, Y1, YAP, (CA)14, from which haplotype III was probably derived, was not found in any populations in this study. The regional distribution of each haplotype revealed that type III is more frequently observed in Okinawa (16%) and in Korea (21%) than in Honshu (4.4%). The haplotype analysis of the Y chromosome may contribute to the exploration of the origin of Japanese and the relationship between east Asian populations.

DNA-Binding Proteins↗

Spermatogenic ability is different among males in different Y chromosome lineage.

It is a controversial question whether sperm concentrations in humans are changing. Several researchers have reported on environmental factors affecting sperm quality, but the influence of genetic factors is still not fully understood. In this study, we examined the relationship between Y chromosome haplotypes and sperm concentration in fertile males. In addition, we determined the haplotypes of azoospermic patients. The results show that the mean sperm concentration correlates with Y chromosome type. Moreover, the occurrence of azoospermia is related to one particular Y chromosome lineage. Thus, males with a certain haplotype are at a disadvantage for fathering children. The difference of spermatogenic ability among men is important not only in pursuing male competition as in the past but also as relates to the future of modern human males.

Fertility↗

Isolation of thermophiles degrading poly(L-lactic acid).

A thermophile, strain 93, which degrades poly(L-lactic acid) (PLA) film was isolated from 144 soil samples obtained from different locations by cultivation using an enrichment culture medium at 60 degrees C. Under this temperature condition, the strain grew on PLA and the dissolved total organic carbon (TOC) concentration in the medium changed according to the growth stage, i.e., after the TOC rapidly reached the minimum, it increased rapidly until it reached the peak and then decreased thereafter. For residual PLA, reduced viscosity decreased rapidly but weight decreased initially slowly with a gradually increasing rate. Gel permeation chromatograms showed a marked decrease in the main peak and the appearance of a new peak in the low molecular weight region. The strain was identified as Bacillus brevis, which has an optimum growth temperature of around 58 degrees C.

Journal Article↗

Functional roles and structural analysis of lung collectins SP-A and SP-D.

Pulmonary surfactant proteins A and D (SP-A and SP-D) belong to the collectin subgroup of the C-type lectin superfamily along with mannose-binding protein (MBP) and conglutinin. Phospholipids are also ligands for collectins, in addition to carbohydrates and glycosphingolipids. SP-A binds dipalmitoylphosphatidylcholine, and SP-D and MBP bind phosphatidylinositol. SP-A also interacts with alveolar type II cells, implicating SP-A in surfactant phospholipid homeostasis. We analyzed an epitope for anti-SP-A monoclonal antibodies that block SP-A-specific functions using a phage display peptide library and SP-A/MBP chimeric proteins. We also investigated the regions of SP-A and SP-D that are required for ligand interactions using SP-A/SP-D chimeras. Lung collectins play key roles in the innate immune system of the lung which is critical for immediate antibody-independent host defense. We have found that SP-A exhibits different interactions with distinct serotypes of lipopolysaccharides and affects differently their elicited cellular responses by a direct interaction with the lipopolysaccharide receptor CD14. In addition to the basic aspects, lung collectins as clinical markers will be discussed.

Binding Sites↗

Serial changes in surfactant-associated proteins in lung and serum before and after onset of ARDS.

The goal of this study was to determine the changes that occur in surfactant-associated proteins in bronchoalveolar lavage fluid (BAL) and serum of patients at risk for ARDS and during the course of ARDS. We found that the concentrations of SP-A and SP-B were low in the BAL of patients at risk for ARDS before the onset of clinically defined lung injury, whereas the concentration of SP-D was normal. In patients with established ARDS, BAL SP-A and SP-B concentrations were low during the entire 14-d observation period, but the median SP-D concentrations remained in the normal range. Immunoreactive SP-A and SP-D were not increased in the serum of patients at risk for ARDS, but both increased after the onset of ARDS to a maximum on Day 3 and remained elevated for as long as 14 d. The BAL SP-A concentrations were significantly lower in at-risk patients who developed ARDS, and no patient with a BAL SP-A concentration greater than 1.2 microg/ml developed ARDS. On Days 1 and 3 of ARDS, the BAL SP-D concentration was significantly lower in patients who died, and the BAL SP-D concentration was significantly related to the PI(O(2))/FI(O(2)) ratio. Thus, surfactant protein abnormalities occur before and after the onset of ARDS, and the responses of SP-A, SP-B, and SP-D differ in important ways. The BAL SP-A and SP-D measurements can be used to classify patients as high or low risk for progression to ARDS and/or death after the onset of ARDS. Strategies to increase these surfactant proteins in the lungs of patients with ARDS could be useful to modify the onset or the course of ARDS.

APACHE↗

Purification and biochemical characterization of pulmonary surfactant protein A of horses.

OBJECTIVE: To characterize surfactant protein isolated from bronchoalveolar lavage fluids of healthy horses. ANIMALS: 10 Thoroughbreds (5 males, 5 females; 26 to 40 months old) that did not have a history or clinical signs of respiratory tract disease. PROCEDURE: Bronchoalveolar lavage fluid (BALF) was obtained and centrifuged at 33,000 X g. Lipid was removed from precipitated fractions by means of extraction with 1-butanol, and organic solvent-insoluble protein precipitates were dialyzed against Tris buffer. The suspension was centrifuged, and supernatant was placed in a mannose-Sepharose affinity column, with calcium. The bound protein fraction was analyzed by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, western immunoblot analysis, and amino acid sequencing. A liposome-aggregation assay was also performed, using purified proteins. RESULTS: Protein isolated by use of mannose-affinity matrices was identified as surfactant protein A (SP-A). It had carbohydrate-binding and phospholipid-aggregation properties characteristic of SP-A isolated from other animal species. The partial primary sequence of the isolated protein had high homology with rat and human SP-A. Furthermore, the equine SP-A reacted with anti-human and anti-rat SP-A specific antibodies. CONCLUSION: Analysis of these findings indicated the existence of SP-A in pulmonary tissues of horses. CLINICAL RELEVANCE: Measurement of SP-A concentrations may be useful for clinicians evaluating pulmonary disease of horses.

Amidohydrolases↗