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Biomedical subjects

N Azuma

Publications and source records attributed to N Azuma.

At least 91 records · Page 5Linked to original sources
PubMed1995

Biochemical studies of glycosaminoglycans in nanophthalmic sclera.

BACKGROUND: Since Brockhurst reported the connection between uveal effusion in nanophthalmic eyes and their scleral alterations and treated them with vortex vein decompression or sclerectomy, many observers have found abnormal accumulation of glycosaminoglycans (GAGs) in nanophthalmic sclera. These GAG abnormalities were thought to effect the collagen changes, though it was not clear which GAGs were changed. METHODS: GAGs were isolated and their contents were determined in scleral specimens from three nanophthalmic patients and five age-matched controls, using electrophoresis and the cetylpyridinium method. RESULTS: Hyaluronic acid, dermatan sulfate and chondroitin sulfate were the major GAGs in both nanophthalmic and control samples. Nanophthalmic sclera showed 2.4-fold, 10-fold and 5.5-fold increases in hyaluronic acid, dermatan sulfate and chondroitin sulfate, respectively, compared with the controls. CONCLUSION: The results suggest that increased levels of GAGs, particularly of dermatan sulfate and chondroitin sulfate may contribute to the abnormalities of collagen fibrillogenesis and be closely involved with the pathogenesis of nanophthalmos.

Adult↗
PubMed1995

Identification of the neurotrophic factor sequence of prosaposin.

Prosaposin, recently identified as a neurotrophic factor (1), is the precursor of saposins A, B, C, and D. The neurotrophic activity of prosaposin resides in the saposin C domain. We have pinpointed the active sequence to a linear 12-mer located in the NH2-terminal sequence of saposin C (LIDNNKTEKEIL). Nanomolar concentrations of a 22-mer peptide encompassing this region stimulated neurite outgrowth and choline acetyltransferase activity, and prevented cell death in neuroblastoma cells. In primary cerebellar granule cells, the 22-mer also stimulated neurite outgroth. Studies of the neuroblastoma line NS20Y using a radiolabeled 18-mer from the neurotrophic region identified a high-affinity (Kd = 70 pM) binding site indicative of receptor-ligand interaction. The 22-mer stimulated protein phosphorylation of several proteins, some of which were tyrosine-phosphorylated after brief exposure similar to saposin C. Circular dichroism studies demonstrated that the 22-mer was converted from a random to a helical structure by addition of ganglioside GM1. The results are consistent with receptor-ligand binding by the peptide initiating a signal transduction cascade and resulting in neuronal differentiation.

Amino Acid Sequence↗
PubMed1995

Long-term clinical evaluation of an adsorbent column (BM-01) of direct hemoperfusion type for beta 2-microglobulin on the treatment of dialysis-related amyloidosis.

The clinical efficacy and safety of a beta 2-microglobulin (beta 2M) adsorbent column, BM-01, on the treatment of dialysis-related amyloidosis were investigated in 7 hemodialysis patients for more than 6 months. The percent reduction of serum beta 2M was more than 60-70%, and the level at the end of each session was less than 10 mg/L in almost all patients. The amount of beta 2M removed was calculated as more than 200-300 mg/session. The results demonstrated that BM-01 performed very well for removing beta 2M, was capable of maintaining less than 25 mg/L of time average concentration (TAC) for beta 2M, and improved the clinical symptoms. Clinically severe side effects were not observed. We recommend that BM-01 should undergo further evaluation for its usefulness in the long-term treatment of dialysis-related amyloidosis, though treatment with the column may not be successful in preventing the onset of the disease.

Acrylic Resins↗
PubMed1995

Rapid and simple procedure for purifying PAS-4 glycoprotein from bovine milk fat globule membrane.

The isolation and partial characterization of PAS-4 glycoprotein (78 kDa) from bovine milk fat globule membrane (MFGM) is described. PAS-4 was selectively extracted with Triton X-114 nonionic detergent and then fractionated on DEAE-Sepharose at pH 7.5. The PAS-4 fraction that was not bound on DEAE-Sepharose gave a single band by SDS-PAGE. The recovery of PAS-4 was 57.4% from MFGM. An amino acid analysis found a high percentage of nonpolar residues. Approximately 7.2% of carbohydrate from PAS-4 was composed of mannose, galactose (Gal), N-acetylglucosamine, N-acetylgalactosamine (GalNAc), and sialic acid, most of the Gal and GalNAc in PAS-4 being released after mild alkaline hydrolysis. This indicated that PAS-4 contained both N- and O-linked sugar chains in concordance with the results of lectin affinity. PAS-4 had apparent isoelectric points of 7.45, 7.41, and 7.32, but these were shifted to pI 7.47 by a neuraminidase treatment. The apparent molecular weight of PAS-4 after deglycosylation with N-glycanase was approximately 57,000 by SDS-PAGE.

Animals↗
PubMed1995

Polymyositis associated with thymoma and the subsequent development of pure red cell aplasia.

A 53-year-old woman with polymyositis associated with thymoma subsequently developed pure red cell aplasia (PRCA). She was hospitalized because of fever and muscle weakness, and diagnosed as having polymyositis by muscle biopsy. Remarkable clinical improvement followed administration of prednisolone. Progressive anemia became evident, however, while prednisolone was being tapered. Erythroid aplasia and the presence of thymoma confirmed the diagnosis of PRCA. Further examinations revealed that cytotoxic T cells may play an important role in the pathogenesis of this case.

Cytotoxicity, Immunologic↗
PubMed1995

[A morphological study on extension of extraretinal vasoproliferation in retinopathy of prematurity].

The relation between extension of extraretinal vasoproliferation and vitreous fibers in stage 3 mild retinopathy of promaturity was evaluated by light and electron microscopy using 4 eyes obtained after autopsies. Seven developing human eyes from 20 to 40 weeks' gestation were used as controls. At an early stage, when vascular tissues broke the inner limiting membrane of the retina and grew into the vitreous cavity, they extended vertically from the retina. Proliferating extraretinal vessels extended towards the posterior surface of the lens. They ran side by side with the framework of vitreous fibers. Electron microscopy demonstrated multiple attachments between vascular endothelia and vitreous fibers. Normal developing vitreous fibers were very dense and homogeneous, running towards the lens not only from the vitreous base but also from the retina at the equator and at the posterior pole. These findings suggest that extension of extraretinal vasoproliferation in retinopathy of prematurity is induced by the framework of the developing vitreous.

Humans↗
PubMed1995

[Experimental evaluation of a new gelatin-impregnated woven Dacron vascular prosthesis (CL301)].

We investigated the biological response and biodegradation of CL301, a presealed woven Dacron prosthesis (UBE woven) with glutaraldehyde stabilized gelatin. The sealant does not affect its handling characteristics because of the glycerin treatment. The total content of endotoxin in the CL301 was 5.3 +/- 0.5 pg/mg of sealant material (1.7 +/- 0.2 pg/cm2), which was 1/5 and 1/6 of that found in Hemashield and Gelseal, respectively. The pyrogen test was negative and the content was estimated below the minimum pyrogenic doses for thoracic aortic surgery. Five cm-long grafts with a diameter of 10 mm were implanted into the descending thoracic aorta of dogs weighing 10-16 kg. These grafts were retrieved 2 hours, 7, 10 days, 5, 8 and 10 weeks after implantation. Thrombus-free surfaces were 28%, 77%, at 5 and 10 weeks and there was no excessive inflammatory response to the sealant. The total, and the effective sealant remaining were 80.6%, 56.5% at 5 weeks, 60.8%, 38.3% at 10 weeks, respectively. The sealant was removed more rapidly from the inner surface than from the outer. In half of the graft area, the sealant was removed or detached from the Dacron surface 5 weeks after implantation, indicating that delayed resorption of the sealant substantially did not affect the healing process. We conclude that because of the harmless amount of endotoxin and effective sealing for 5 weeks, followed by an acceptable healing process experimentally, CL301 is the presealed Dacron graft of choice for thoracic aortic surgery.

Animals↗
PubMed1995

Expression of inflammatory cytokines and adhesion molecules in haemodialysis-associated amyloidosis.

BACKGROUND: The occurrence of various arthropathies including carpal-tunnel syndrome (CTS) in dialysis-associated amyloidosis, a condition caused by the deposition of beta 2 microglobulin (beta 2MG), has been emphasized for several years. We attempted to analyse the pathogenesis of CTS in haemodialysis-associated amyloidosis (HA). METHODS: The expression of cell adhesion molecules and inflammatory cytokines in tenosynovial tissues was determined by using both reverse-transcriptase polymerase chain reaction (RT-PCR) and immunostaining. RESULTS: There was a marked expression of ICAM-1, VCAM-1, E-selectin mRNAs together with increased mRNA expression of inflammatory cytokines (IL-1 beta, TNF alpha, IL-6 and MCP-1) in proliferating synovial tissues. ICAM-1 was expressed not only on vascular endothelial cells, but also on synovial cells. In contrast, both VCAM-1 and E-selectin were exclusively expressed on endothelial cells. Mononuclear cells bearing CD13, CD14, CD33 and HLA-DR with macrophage-like morphology were accumulated in the perivascular area and expressed VLA-4, LFA-1 and Mac-1. Moreover, synovial lining cells, vascular endothelial cells and infiltrated mononuclear cells expressed chemokines such as MCP-1 and MIP-1 alpha. CONCLUSIONS: These data suggest that upregulated expression of inflammatory cytokines and adhesion molecules promotes activation and infiltration of macrophages causing CTS in haemodialysis-associated amyloidosis patients.

Amyloidosis↗
PubMed1994

Stimulation of acid ceramidase activity by saposin D.

Ceramide is ubiquitously present in plasma membranes and plays a pivotal role in metabolism of sphingolipids. In addition, ceramide and its hydrolytic product, sphingosine, may have important roles as second messengers for cell function and survival. Ceramide is hydrolyzed by both acid and alkaline ceramidase. In this investigation, saposin D was found to stimulate the acid, but not the alkaline, ceramidase. With a crude membrane enzyme preparation, the stimulation was about fourfold. Saposin D is one of four saposins (sphingolipid activator proteins) that are derived from a single precursor protein, prosaposin. Saposins, A, B, and C had no significant effect on ceramidase activity. A kinetic study showed that the stimulation by saposin D was caused by decreasing its Km value for ceramide without a significant change in its Vmax value. A binding study demonstrated that saposin D, as well as saposins A, B, and C, binds to ceramide at neutral pH but not at acidic pH. Preliminary evidence suggests that partially purified acid ceramidase contains bound saposin D. These findings suggest that saposin D facilitates acid ceramidase activity primarily by interaction with the enzyme. The function of saposin D as a modulator of ceramide concentration in vivo has been suggested by the accumulation of ceramide in tissues of patients with total saposin deficiency.

Acid Ceramidase↗
PubMed1994

Histochemical and immunohistochemical studies on keratan sulfate in the anterior segment of the developing human eye.

Changes in the distribution of keratan sulfate in the anterior segment of developing ocular tissue were investigated histochemically and immunohistochemically using human eyes from 5 weeks gestation to 2 years after birth. Enzyme digestion methods with streptomyces hyaluronidase, chondroitinase and keratanase showed that the main component of glycosaminoglycans in the cornea was hyaluronic acid at the early stage and chondroitin sulfate from the middle stage to the neonatal stage. Keratan sulfate was found at the neonatal stage. Immunohistochemical staining, however, showed that keratan sulfate was present from 6 weeks around mesenchymal cells which migrated into the anterior portion. The stroma and endothelial cells of the cornea, trabecular tissue, iris, choroidal tissue of the ciliary body and anterior tunica vasculosa lentis were the next tissues to show positive for immunostaining. Keratan sulfate became limited to the cornea and lumbus and mostly disappeared from the other anterior segment tissues after birth. These findings suggest that tissues which seem to originate from mesenchymal cells and surround the chamber space contain keratan sulfate during the developmental stage.

Adolescent↗
PubMed1994

Development of transient thyroid disease and reaction during treatment of chronic hepatitis C with interferon.

Six of 50 (12%) patients with chronic hepatitis C who were treated with interferon developed thyroid disease or an autoimmune thyroid reaction while undergoing treatment. One patient developed silent thyroiditis, with an increase in serum triiodothyronine (T3), thyroxine (T4), free T3, free T4, and markedly suppressed thyroid-stimulating hormone (TSH) levels, accompanied by the appearance of both antithyroglobulin (TgAb) and antimicrosomal antibodies (McAb). One patient developed hypothyroidism in association with moderately elevated TSH levels and high titers of McAb. TSH, TgAb, and McAb levels returned to the initial values at least 4 months after the end of interferon treatment (9 months of follow up). Four patients whose TgAb and/or McAb levels were elevated during treatment with interferon had been diagnosed as having subclinical autoimmune thyroiditis; however, their thyroid function remained in the normal range. These results suggested that treatment with interferon can cause a transient autoimmune thyroid reaction and disease as a side effect.

Autoantibodies↗
PubMed1994

Histamine and tryptase levels in allergic conjunctivitis and vernal keratoconjunctivitis.

Tryptase is useful as a specific and accurate indicator of mast cell activation, whereas histamine, a mast cell's major mediator, also exists in basophils. The aim of this study is to investigate histamine and tryptase levels in allergic conjunctiva. We measured histamine and tryptase levels in conjunctival epithelial cell suspension of children with allergic conjunctivitis (AC) and vernal kerato-conjunctivitis (VKC), and controls, and we evaluated correlations with clinical observations. Both the histamine and tryptase levels in VKC were significantly higher than controls (p < 0.05, p < 0.01), and histamine levels in VKC was also greater than AC (p < 0.05). The histamine/tryptase (H/T) ratios were 0.03 +/- 0.04 in AC, 0.08 +/- 0.09 in VKC and 0.006 +/- 0.006 in controls. The H/T ratios in VKC were significantly higher than controls (p < 0.05) and AC (p < 0.05), and were also found to correlate with the superficial punctate keratopathy (SPK) score (r2 = 0.89). Analyzing the histamine and tryptase levels in conjunctival epithelium may be useful in evaluating the allergic ocular surface, especially in the cases with SPK, where the increase in the histamine levels is not accompanied by an increase in tryptase levels. This suggests an important role for inflammatory cells such as basophils infiltrating into the conjunctival epithelium in allergic reactions.

Child↗
PubMed1994

Expression of type II collagen at the middle stages of chick embryonic and human fetal skin development.

Using in situ hybridization techniques and RNase protection assays, type II collagen mRNA was transiently detected in the epidermis of chick embryonic skins during days 9-15 after fertilization, with a maximum expression at day 11. Immunohistochemical studies demonstrated that deposition of type II collagen was also transiently localized at the subepidermal region during days 10-15. Type II collagen gene and gene product concomitantly started to decline preferentially at the region where feather buds were being formed on day 12, and thereafter diminished at the region between feather buds. Using immunohistochemical methods, type II collagen was also detected in human fetal scalp skin at 17-23 fetal weeks at the subepidermal region, excluding the region beneath the hair follicles. These results indicate that the lack of type II collagen expression is related to the development of feather and hair at a certain stage of chick embryonic and human fetal skin development.

Animals↗
PubMed1994

Production of overmodified type I procollagen in a case of osteogenesis imperfecta.

Collagen synthesis in cultured skin fibroblasts from a patient with osteogenesis imperfecta was studied. Approximately 2 fold accumulation of collagen in the cell layer was found. The slower mobility of pro alpha 1 (I) and pro alpha 2 (I) as well as alpha 1 and alpha 2 (I) polypeptide on sodium dodecylsulfate-polyacrylamide gel electrophoresis was detected, indicating that abnormal posttranslational modification could be present in type I procollagen in patient fibroblasts. The degrees of hydroxylation and subsequent glycosylation of lysine residues in the affected collagen were elevated 1.5 and 1.4 fold, respectively. There were no significant changes in the relative content of type III to type I collagen nor the incorporation of mannose into the carboxyterminal propeptide of pro alpha 1 (I) and pro alpha 2 (I). These results indicate that the patient produces an over-modified type I procollagen which is responsible for the clinical features and has a collagen abnormality already reported in type II osteogenesis imperfecta.

Cells, Cultured↗
PubMed1994

[Recent advances and problems in peripheral arterial reconstruction].

Recent advances in the field of peripheral arterial reconstruction have been remarkable. These advances are mainly derived from the development of diagnostic technology such as Doppler ultrasound analysis, further refinement of surgical technique including surgical instruments and materials, and naturally improvement of patient care in the pre-, peri- and postoperative period. During the past 14 years we have performed peripheral arterial reconstruction in 1,200 cases (1,660 limbs) mainly with occlusive lesion due to arteriosclerosis obliterans. In our hand, aorto-iliac occlusive lesion has been routinely bypassed with Dacron prostheses and the secondary patency rate at eleven years reached 96.5%. The main problems encountered in this region were anastomotic aneurysm in the femoral artery (3.9%) and graft infection (1.2%). In the infrainguinal region there are still problems to be solved, although the primary (secondary) 5 year patency rates of reversed vein graft as well as in situ vein graft including femoro-popliteal below knee and femoro-crural bypasses have exceeded 70% (85%). First, there is no graft material comparable to the autogenous vein (AVG). Secondly, many of the AVG should suffer occlusive pathological changes from the environment in the long term following surgery. At the present time, we have no effective method to solve these problems, therefore we should follow up the patients heedfully to maintain the graft patency as well as to improve their quality of life and prognosis.

Anastomosis, Surgical↗
PubMed1994

["Extended aortic arch anastomosis" in Shone's anomaly--a case report].

We report a case of a newborn with Shone's anomaly in whom the parachute mitral valve, mild subaortic stenosis, hypoplastic aortic arch, and severe coarctation of the aorta were found. The patient was 10 days old, who had symptoms of low output syndrome due to the progressive obstruction of patent ductus arteriosus, underwent "extended aortic arch anastomosis" to repair the hypoplastic aortic arch and severe coarctation of the aorta. This surgical procedure, resulting in a successful post-operative course of the patient, might be effective in such anomalies.

Anastomosis, Surgical↗