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Biomedical subjects

A Ando

Publications and source records attributed to A Ando.

At least 109 records · Page 6Linked to original sources
PubMed1998

[A case report of dumbbell neurogenic tumor of the superior mediastinum].

A 15-year-old female was admitted because of the superior mediastinum mass on chest X-rays and sensory loss of ulnar side of the left arm. Computed tomographic scanning and magnetic resonance imaging revealed that the tumor was dumbbell-shaped and invaded the vertebral canal through the intervertebral foramen between C 7 and Th 1. At first laminectomy of vertebrae (C 6-Th 1) was made in a prone position and intra-spinal portion of the tumor was resected. Then the patient was placed in a supine position and the chest was opened by left hemicollar incision and sternotomy to the 2nd intercostal space. The tumor was divided into two parts at the level of 1st rib and completely removed. The pathological diagnosis was schwannoma. This procedure is safe and useful for dumbbell type tumor located in superior mediastinum, especially in case of large tumor from neck to the thoracic cavity.

Adolescent↗
PubMed1998

Surgical outcome on combined procedures of lens extraction, intraocular lens implantation, and vitrectomy during removal of the epiretinal membrane.

BACKGROUND AND OBJECTIVE: The authors evaluated the outcome of combined procedures of lens extraction, intraocular lens implantation, and vitrectomy during procedures for the removal of the epiretinal membrane, and attempt to clarify which factors affected the outcome of surgery. PATIENTS AND METHODS: Surgery for the removal of the epiretinal membrane was performed and a 2-year follow-up program was maintained for 32 eyes at the authors' clinic during the past 5 years. The combined procedure was undertaken in 15 eyes, whereas a simple vitrectomy was performed in 17 eyes. Results were analyzed by postoperative ophthalmoscopic and slit-lamp examinations for visual acuity and complications. RESULTS: Six months after surgery, visual acuity improved similarly in both groups. But, 2 years after surgery, 11 eyes (65%) that underwent a simple vitrectomy showed decreased visual acuity due to the advancement of cataracts. The postoperative visual acuity at 6 months correlated to preoperative visual acuity, and the advancement of cataracts tended to correlate inversely to the age of the patients. Major complications did not occur in any of the cases. CONCLUSION: Earlier surgical management is better for treatment of the epiretinal membrane, and a combined procedure has advantages in cost reduction and is less troublesome, especially for elderly patients.

Adult↗
PubMed1997

Cell cycle-dependent phosphorylation of p27 cyclin-dependent kinase (Cdk) inhibitor by cyclin E/Cdk2.

The cyclin-dependent kinase (Cdk) inhibitor p27 interrupts progression of the cell cycle by inhibiting various cyclin/Cdk activities. Since the protein level of p27 does not correlate with its mRNA level or protein synthesis rate in most cases, it is suggested that degradation of the protein may be regulated via an unidentified mechanism(s) involving a post-translational modification(s). We present evidence here that p27 phosphorylation is cell cycle-dependent and peaks in the late G1 phase and that the level of p27 protein is inversely correlated with its phosphorylation. Although both cyclin D1- and cyclin-E-dependent kinases are active in the late G1 phase in human fibroblasts, cyclin E/Cdk2 specifically phosphorylates p27 on threonine-187 in vitro. Interestingly, ectopic expression of T187A revealed that it was far more stable in vivo than wild type p27. Thus, phosphorylation of p27 by cyclin E/ Cdk2 may affect the stability of its protein and play a role in how the protein functions.

Amino Acid Substitution↗
PubMed1997

Four mutant alleles of the insulin receptor gene associated with genetic syndromes of extreme insulin resistance.

We identified four novel mutant alleles of the insulin receptor gene in three patients with genetic syndromes associated with insulin resistance. Two mutant alleles of the insulin receptor gene were identified in a patient with the Rabson-Mendenhall syndrome who was a compound heterozygote for a mutation at the 3'-splice acceptor site of intron 4 (AG-->GG), the first mutation causing an aberrant splicing at this locus, and a deletion of eight base pairs in exon 12. The second patient with leprechaunism was also a compound heterozygote for a deletion of one base pair in exon 19 and a mutation, Thr910-->Met, which causes impaired receptor processing. Interestingly, the third patient with type A syndrome was a simple heterozygote for the identical one base pair deletion. The fact that the same one base pair deletion links to type A in a simple heterozygote and to leprechaunism in a compound heterozygote appears consistent with the hypothesis that the severity of mutations will determine the phenotype.

Alternative Splicing↗
PubMed1997

Physical mapping 220 kb centromeric of the human MHC and DNA sequence analysis of the 43-kb segment including the RING1, HKE6, and HKE4 genes.

A cosmid contig was constructed from a YAC clone with a 220-kb insert that spans the centromeric side of the human MHC class II region, corresponding to the mouse t complex. The gene order was identified to be HSET-HKE1.5-HKE2-HKE3-RING1-HKE6- HKE4 (RING5). The genomic sequence of a 42,801-bp long region encoded by one cosmid clone in the RING1, HKE6, and HKE4 subregions was determined by the shotgun method. The exon-intron organization of these three genes, RING1 (Ring finger protein), HKE6 (steroid dehydrogenase-like protein), and HKE4 (transmembrane protein with histidine-rich charge clusters), was determined. The previously reported RING2 gene was revealed to be identical to HKE6. Transcripts from HKE4 were detected in the placenta, lung, kidney, and pancreas. Those of HKE6 were found in the liver and pancreas. The 25-kb region proximal to the RING1 gene includes an extensive dense cluster of Alu repeats (about 1.2 Alu per kb), and no gene has been identified in this so far. The region is equivalent to part of the mouse t complex and could be of relevance to human development.

Amino Acid Sequence↗
PubMed1997

Nucleotide sequence analysis of the HLA class I region spanning the 237-kb segment around the HLA-B and -C genes.

To elucidate the detailed gene organization of the human leukocyte antigen (HLA) class I region on chromosome 6, seven contiguous cosmid genomic clones covering the 237-kb segment around the HLA-B and -C loci were subjected to DNA sequencing by the shotgun strategy to give a single contig of 236,822 bp from the MICA gene (58.2 kb centromeric of HLA-B) to 90.8 kb telomeric of HLA-C. This region was confirmed to contain four known genes, MICA, HLA-17, HLA-B, and HLA-C, from centromere to telomere. Further, a new member of the P5 multicopy genes was found to be about 1.3 kb upstream of the HLA-17 gene and designated P5.8. Five novel genes designated NOB1-5 were identified by RT-PCR and Northern blot hybridization. In addition, two pseudogenes, dihydrofolate reductase pseudogene (DHFRP) and ribosomal protein L3 homologous gene (RPL3-Hom), were also found in the vicinity of the HLA-B and -C genes, respectively. The two segments (about 40 kb) downstream of the HLA-B and HLA-C genes showed high sequence homology to each other, suggesting that segmental genome duplication including the major histocompatibility complex (MHC) class I gene must have occurred during the evolution of the MHC.

Blotting, Northern↗
PubMed1997

Gene organization of human NOTCH4 and (CTG)n polymorphism in this human counterpart gene of mouse proto-oncogene Int3.

The cDNA and genomic clones for the human counterpart of the mouse mammary tumor gene Int3 were isolated and sequenced. We designated this human major histocompatibility complex (MHC) class III gene as NOTCH4, since very recently, by sequencing cDNA clones, the complete form of the mouse proto-oncogene Int3 has been clarified and named Notch4. The present human NOTCH4 sequence is the first example of the genomic sequence for the extracellular portion of the mammalian Notch4, and by comparing it with the mouse Notch4 cDNA sequence, the exon/intron organization was clarified. The comparison of the predicted amino acid sequence of human NOTCH4 with those of other Notch homologues of a wide range of species revealed four subfamilies for mammalian Notch. In the protein coding region of human NOTCH4, we found (CTG)n repeats showing a variable number tandem repeat (VNTR) polymorphism for different human leukocyte antigen (HLA) haplotypes. Ten genes mapped on 6p21.3, including NOTCH4, were found to have counterparts structurally and functionally similar to those mostly mapped on 9q33-q34, indicating segmental chromosome duplication during the course of evolution. Similarity of genes on chromosomes 1, 6, 9 and 19 was also discussed.

Amino Acid Sequence↗
PubMed1997

Thrombotic microangiopathy associated with alpha-interferon therapy for chronic myelocytic leukemia.

A 31-year-old man diagnosed as having chronic myelocytic leukemia (CML) developed renal insufficiency with nephrotic-range proteinuria during alpha-interferon (IFN) therapy for CML. A renal biopsy specimen showed remarkable thrombotic microangiopathic lesions resembling those of hemolytic-uremic syndrome. The patient had papules on both lower legs, and a cutaneous biopsy showed similar microangiopathic lesions in dermal and subcutaneous vessels. Although discontinuation of IFN and initiation of prednisolone therapy resulted in resolution of proteinuria, renal insufficiency persisted. These findings suggest that long-term IFN therapy can induce late-onset thrombotic microangiopathy in systemic microvessels.

Adult↗
PubMed1997

Triplet repeat polymorphism in the NOTCH4 gene with the human major histocompatibility complex in a healthy population and patients with a salivary gland tumor in Japan.

The NOTCH4 gene, the human counterpart of the mouse mammary tumor gene, int-3, has been recently localized near the boundary of the HLA class II and class III regions. This gene is one of candidates for development of salivary gland tumor. Microsatellite polymorphism of (CTG)n repeat in the signal peptide domain of NOTCH4 was analyzed in Japanese including the patients with salivary gland tumor. Four alleles consisting of 6, 9, 10 and 11 repetitions of CTG (Leu) were observed and found to be in linkage disequilibria with HLA class I and class II alleles. No significant association of this microsatellite polymorphism with the disease were observed in 26 samples of salivary gland tumor. In this neoplasia, neither large-scale deletion nor translocation was detected around the NOTCH4 gene using genomic Southern hybridization analysis by the NOTCH4 cDNA as a probe.

Alleles↗
PubMed1997

Triplet repeat polymorphism within the NOTCH4 gene located near the junction of the HLA class II and class III regions in narcolepsy.

A polymorphic (CTG)n microsatellite repeat was found in the signal peptide domain of the NOTCH4 gene located near the junction of the class II and class III regions of the human major histocompatibility complex. This gene belongs to a multigene family of NOTCH originally identified as a differential factor of neuronal cells. To ascertain whether the NOTCH4 gene is involved in the development of neurogenic disease, narcolepsy, which is known to be tightly associated with HLA-DR15, this microsatellite polymorphism of the (CTG)n repeat was analyzed in Japanese patients with narcolepsy One allele, 9 repetitions of CTG (Leu) was significantly increased in the patient group. However, the significant increase of this allele in the patient group could be explained by a strong linkage disequilibrium with the HLA class II alleles, DRB1*1501, DQA1*0102 and DQB1*0602, which were more strongly associated with the disease. These results suggest that the (CTG)n repeat polymorphism in NOTCH4 does not primarily determine the susceptibility to narcolepsy.

Alleles↗
PubMed1997

Precise switching of DNA replication timing in the GC content transition area in the human major histocompatibility complex.

The human genome is composed of long-range G+C% (GC%) mosaic structures thought to be related to chromosome bands. We previously reported a boundary of megabase-sized GC% mosaic domains at the junction area between major histocompatibility complex (MHC) classes II and III, proposing it as a possible chromosome band boundary. DNA replication timing during the S phase is known to be correlated cytogenetically with chromosome band zones, and thus the band boundaries have been predicted to contain a switch point for DNA replication timing. In this study, to identify to the nucleotide sequence level the replication switch point during the S phase, we determined the precise DNA replication timing for MHC classes II and III, focusing on the junction area. To do this, we used PCR-based quantitation of nascent DNA obtained from synchronized human myeloid leukemia HL60 cells. The replication timing changed precisely in the boundary region with a 2-h difference between the two sides, supporting the prediction that this region may be a chromosome band boundary. We supposed that replication fork movement terminates (pauses) or significantly slows in the switch region, which contains dense Alu clusters; polypurine/polypyrimidine tracts; di-, tri-, or tetranucleotide repeats; and medium-reiteration-frequency sequences. Because the nascent DNA in the switch region was recovered at low efficiency, we investigated whether this region is associated with the nuclear scaffold and found three scaffold-associated regions in and around the switch region.

Base Sequence↗
PubMed1997

[Four cases of thymoma associated with pure red cell aplasia].

Thymomas associated with pure red cell aplasia (PRCA) constituted only 3.3% of 122 thymomas treated in our department from 1963 to March, 1995. Four patients with this disease (2 men and 2 women, mean age: 58 years, range: 41 to 66 years old) are reported. Auto-antibodies were found in all 4 cases, increase of T cell in two, suppression of erythropoietin production in one, and antibody to EB virus in one. Operation was performed in all cases (two thymothymectomies, one extended thymothymectomy, and one thymomectomy), and 3 of 4 patients were in the progressive stage of Masaoka's classification (I, III, IVa, and IVb each). As for the pathological findings, mixed type was found in three cases and lymphocyte predominant type in one. Two patients died from radiation pneumonia. As for PRCA, postoperative therapy was effective (100%) in all patients.

Adult↗
PubMed1997

[Indocyanine green infrared fluorescence angiography and histopathological correlation in experimental choroidal circulatory disturbance. Report 2].

We performed an experimental study on choroidal circulatory disturbance to clarify basic problems about interpretation of retino-choroidal lesions in indocyanine green fluorescence angiography (ICG angiography). We severed the posterior ciliary arteries to produce choroidal circulatory disturbance. Fluorescein angiography and ICG angiography were performed at one week, and one month after occlusion. These findings were compared with histopathological findings. One week after occlusion, the area of choroidal infarct showed occlusion of choriocapillaris and proliferation of the retinal pigment epithelial (RPE) cells, this area showed hypofluorescence in the early phase ICG angiography. The hypofluorescence area increased in the late phase. One month after occlusion, the lesion showed loss of choriocapillaris at the center and proliferation of fibroblast-like cells at the edge of the lesion. The subretinal strand showed hyperfluorescence in late phase ICG angiography. Proliferated RPE cells masked ICG fluorescence in the late phase. Fibroblast-like cells showed tissue staining. When reading ICG angiography, we have to take into account that the ICG angiogram is greatly modified by condition of the RPE.

Animals↗
PubMed1997

TCV-116 inhibits interstitial fibrosis and HSP47 mRNA in rat obstructive nephropathy.

Unilateral ureteral obstruction (UUO) is a well established disease model leading to fibrosis of the obstructed kidney. In this model, involvement of enhanced renin-angiotensin system in the pathogenesis of interstitial fibrosis has been demonstrated. A 47-kDa heat-shock protein (HSP47) was originally identified as a collagen-binding stress protein, and is currently considered to be a collagen-specific molecular chaperone that plays a pivotal role during the biosynthesis and secretion of procollagen from endoplasmic reticulum. To test if HSP47 is involved in interstitial fibrosis in UUO, we examined the expression of HSP47 mRNA in rat UUO kidneys after 12 hours. 1, 4, 7 days of obstruction. HSP47 mRNA expression was significantly increased as early as 12 hours after obstruction and was sustained at the increased level until seven days. Type I collagen mRNA significantly increased after four days of UUO. Fibrotic changes of interstitium appeared in Masson's trichrome stained section after four days. To explore the possible involvement of angiotensin II (Ang II) in HSP47 induction, the effect of Ang II receptor antagonist (TCV-116) and angiotensin converting enzyme inhibitor (lisinopril) was tested. TCV-116 or lisinopril was given to the animals orally once a day at the dose of 10 mg/kg. TCV-116 or lisinopril significantly ameliorated the fibrotic change of interstitium seven days after obstruction. HSP47 and type I collagen mRNA levels in the TCV-116- or lisinopril-treated groups were reduced to about 60% of untreated UUO. A possible involvement of HSP47 in the pathogenesis of interstitial fibrosis in UUO is suggested; however, further investigation is required to identify the signals involved in the induction of HSP47 in UUO.

Angiotensin II↗
PubMed1996

Production of intense low-energy positron beams with synchrotron radiation.

A low-energy positron beam is a unique probe of Fermi surfaces, defects, surfaces and interfaces. In high-energy electron and positron storage rings (E > 6 GeV) it is possible to generate intense synchrotron radiation with 1-3 MeV photons by installing a high-field superconducting wiggler. The strength of the wiggler should be ~8-12 T. High-energy photons are emitted from the wiggler and converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be ~10(10)-10(12) (slow-e(+) s(-1)) with the size of positron source ~10(2)-10(3) cm(2). The possibility of increasing the brightness of the low-energy positron beam is discussed. Advantages of using synchrotron radiation for producing positrons are pointed out. The effect of a superconducting wiggler on the stored electron beam is also discussed.

Journal Article↗