Biomedical subjects

R Inagi

Publications and source records attributed to R Inagi.

At least 37 records · Page 2Linked to original sources

PubMed1999

Oxidative protein damage with carbohydrates and lipids in uremia: 'Carbonyl stress'.

Chronic uremia appears to be in a state of an increased oxidative stress. Under oxidative stress, proteins are modified directly by reactive oxygen species with the eventual formation of oxidised amino acids. Proteins are also modified indirectly with reactive carbonyl compounds formed by the autoxidation of carbohydrates and lipids, with the eventual formation of the advanced glycation/lipoxidation end products (AGEs/ALEs). AGEs, pentosidine and carboxymethyllysine (CML), and ALE, malondialdehyde (MDA)-lysine, are elevated in plasma and matrix proteins of uremic patients several times above normal subjects. Precursor carbonyl compounds derived from carbohydrates and lipids are indeed elevated in uremic circulation. Uremia thus appears to be in a state of carbonyl overload with potentially damaging proteins (carbonyl stress). Carbonyl stress might be relevant to long-term complications associated with chronic renal failure and dialysis, such as dialysis-related amyloidosis and atherosclerosis. Immunohistochemical studies identified carbonyl stress in long-lived amyloid deposits and vascular lesions. Proteins modified under carbonyl stress exhibit several biological activities, which might, at least in part, account for the development of joint and vascular complications in uremia.

Carbohydrate Metabolism↗

PubMed1999

Expression of megsin mRNA, a novel mesangium-predominant gene, in the renal tissues of various glomerular diseases.

Mesangial cells play an important role in maintaining a structure and function of the glomerulus and in the pathogenesis of glomerular diseases. Recently, we discovered a new mesangium-predominant gene termed "megsin." Megsin is a novel protein that belongs to the serine protease inhibitor (serpin) superfamily. To elucidate the pathophysiologic role of megsin in the kidney, the expression and localization of megsin mRNA in renal tissues of patients with IgA nephropathy (IgA-N), diabetic nephropathy (DN), minimal change nephrotic syndrome (MCNS), membranous nephropathy (MN), and normal human kidney (NHK) was evaluated by in situ hybridization using digoxigenin-labeled oligonucleotide. Individual cells positive for megsin mRNA were observed only in glomeruli in all renal tissues. Their localization coincided with those of mesangial cells. The percentage of positive cells for megsin mRNA in total glomerular cells was significantly greater in IgA-N than in MCNS, MN, and NHK. It was also significantly greater in DN than in MCNS and NHK. In IgA-N, the percentage of megsin mRNA-positive cells was greater in tissues from those with mesangial cell proliferation and slightly mesangial matrix expansion (periodic acid-Schiff-positive area in the total glomerulus area, <30%; cell number in mesangial matrix area, >30; assessed in cross-sections through their vascular poles) than in tissues from those with severe mesangial matrix expansion (periodic acid-Schiff-positive area in total glomerulus area, >30%; cell number in mesangial matrix area, <30). In conclusion, megsin mRNA was predominantly expressed in glomerular mesangial cells in all renal tissues. The expression of megsin mRNA was upregulated in IgA-N and DN, both of which are diseases accompanied with mesangial cell proliferation and/or mesangial matrix expansion. These data suggest a link of megsin expression to the pathogenesis of IgA-N and DN, two major causes of end-stage renal failure.

Actins↗

PubMed1999

Immunohistochemical evidence for an increased oxidative stress and carbonyl modification of proteins in diabetic glomerular lesions.

Advanced glycation end products (AGE) include a variety of protein adducts whose accumulation has been implicated in tissue damage associated with diabetic nephropathy (DN). It was recently demonstrated that among AGE, glycoxidation products, whose formation is closely linked to oxidation, such as carboxymethyllysine (CML) and pentosidine, accumulate in expanded mesangial matrix and nodular lesions in DN, in colocalization with malondialdehyde-lysine (MDA-lysine), a lipoxidation product, whereas pyrraline, another AGE structure whose deposition is rather independent from oxidative stress, was not found within diabetic glomeruli. Because CML, pentosidine, and MDA-lysine are all formed under oxidative stress by carbonyl amine chemistry between protein amino group and carbonyl compounds, their colocalization suggests a local oxidative stress and increased protein carbonyl modification in diabetic glomerular lesions. To address this hypothesis, human renal tissues from patients with DN or IgA nephropathy were examined with specific antibodies to characterize most, if not all, carbonyl modifications of proteins by autoxidation products of carbohydrates, lipids, and amino acids: CML (derived from carbohydrates, lipids, and amino acid), pentosidine (derived from carbohydrates), MDA-lysine (derived from lipids), 4-hydroxynonenal-protein adduct (derived from lipids), and acrolein-protein adduct (derived from lipids and amino acid). All of the protein adducts were identified in expanded mesangial matrix and nodular lesions in DN. In IgA nephropathy, another primary glomerular disease leading to end-stage renal failure, despite positive staining for MDA-lysine and 4-hydroxynonenal-protein adduct in the expanded mesangial area, CML, pentosidine, and acrolein-protein adduct immunoreactivities were only faint in glomeruli. These data suggest a broad derangement in nonenzymatic biochemistry in diabetic glomerular lesions, and implicate an increased local oxidative stress and carbonyl modification of proteins in diabetic glomerular tissue damage ("carbonyl stress").

Adult↗

PubMed1999

Apolipoprotein E2/E5 variants in lipoprotein glomerulopathy recurred in transplanted kidney.

Lipid abnormalities are associated with various disorders ranging from generalized atherosclerosis to renal diseases, including lipoprotein glomerulopathy that is characterized by glomerular lipoprotein thrombi and causes type III hyperlipoproteinemia, proteinuria, and renal failure. This study examines lipoprotein glomerulopathy, which recurred in a transplanted kidney. Molecular biologic analysis of the patient's apolipoprotein (apo) E gene demonstrated E2/E5 type variants. Immunohistochemical analysis of the diseased kidney demonstrated various lipid peroxidation-specific protein adducts, suggesting a potential role of oxidative stress in this disorder. Recurrence in the transplanted kidney suggested a pathogenic role of extraglomerular humoral component(s) resulting from abnormal lipoprotein metabolism, presumably linked to apo E and other genetic or acquired factor(s). Furthermore, the finding that the patient showed pathologic abnormalities in the transplanted kidney with no clinical signs or symptoms of renal disease indicated that lipoprotein glomerular damage progresses early before any clinical manifestations.

Adult↗

PubMed1999

Prevalences of human herpesvirus 6 and human herpesvirus 7 in normal Thai population.

Prevalences of human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) DNA were investigated in normal Thai population. Peripheral blood mononuclear cells (PBMC) and saliva were collected from 238 healthy adults in five provinces which might be a representative of each part of the country, and 120 normal children in one province. Prevalences of HHV-6 DNA PBMC were 45.5-74.3% in adults and 78.3% in children, and in saliva, very low prevalences were detected; 5.7-8.6% in adults and 15.0% in children, respectively. Additionally, all HHV-6 DNA detected in this study were variant B. Comparingly to those of HHV-7 DNA, the prevalences were significantly higher than those of HHV-6, ie, 82.9-91.4% in PBMC of adults, 85% in PBMC of children, 84.8-89.0% in saliva of adults and 92.5% in saliva of children. HHV-6 and HHV-7 isolation from saliva specimens were also performed. No HHV-6 could be isolated from any samples, whereas, in the present study, HHV-7 could be isolated as 90.0% from children and as 20.0-54.5% from adults.

Adolescent↗

PubMed1998

Generation of protein carbonyls by glycoxidation and lipoxidation reactions with autoxidation products of ascorbic acid and polyunsaturated fatty acids.

Accumulation of carbonyl derivatives of proteins (protein carbonyl) is taken as a biomarker of oxidative protein damage in aging and in various diseases. We detected protein carbonyls in situ in human diabetic arteriosclerotic tissues and characterized the formation of protein carbonyls. Protein carbonyls were identified in the thickened intima of arterial walls and co-localized with protein adducts formed by carbonyl amine chemistry between protein and carbonyl compounds derived from autoxidation of carbohydrates, lipids, and ascorbate, i.e. advanced glycation end products or glycoxidation products, such as carboxymethyllysine (CML) and pentosidine, and lipoxidation products, such as malondialdehyde (MDA) and 4-hydroxy-nonenal (HNE). In vitro incubation of proteins with ascorbic acid accelerated the production of protein carbonyls as well as CML and pentosidine, and incubation with arachidonate accelerated the production of protein carbonyls as well as CML, MDA, and HNE. By contrast, incubation of proteins with glucose resulted in the production of CML and pentosidine, but not protein carbonyls. Schiff base inhibitors, (+/-)-2-isopropylidenehydrazono-4-oxo-thiazolidin-5-ylace tanilide and aminoguanidine, inhibited the production of protein carbonyls after incubation with ascorbate and arachidonate. The present study suggests that ascorbate and polyunsaturated fatty acids, but not glucose, represent potential sources of protein carbonyls, and that both the glycoxidation and lipoxidation reactions contribute to protein carbonyl formation in aging and various diseases.

Arachidonic Acid↗

PubMed1998

Analysis of human herpesvirus 6 U3 gene, which is a positional homolog of human cytomegalovirus UL 24 gene.

The US22 gene family was first discovered in human cytomegalovirus (HCMV) and contains several conserved amino acid motifs. Human herpesvirus 6 (HHV-6) also encodes several genes belonging to the US22 family, including the U3 gene (a positional homolog of HCMV UL24). Because the gene products of the US22 gene family function as gene regulators in general, we analyzed the HHV-6A U3 gene. Six transcripts with different molecular weights of 7.5-1.8 kb were detected by Northern blot analysis using a U3-specific probe. Sequence analyses of the respective cDNA clones and primer extension experiments revealed that the U3 gene encoded the 2.0- and 3.5-kb transcripts and had no splicing within the U3 gene region. By immunofluorescence testing using antibodies raised to a fusion protein of MBP (maltose-binding protein) and U3, the U3 viral antigen was detected as early as 24 h p.i. in HHV-6A-infected U373 cells. The antigens were found in cytoplasmic granules, preferentially in the endoplasmic reticulum. Moreover, cotransfection assay using a luciferase gene expression system revealed that the U3 gene product was capable of activating the human immunodeficiency virus long terminal repeat promoter in CV1 cells.

Cytomegalovirus↗

PubMed1998

A mesangium-predominant gene, megsin, is a new serpin upregulated in IgA nephropathy.

Mesangial cells play an important role in maintaining a structure and function of the glomerulus and in the pathogenesis of glomerular diseases. To identify a specific gene expressed in human mesangial cells, we used a rapid large-scale DNA sequencing and computerized data processing to compare the transcripts in cultured human mesangial cells with various different cells and organs. Using this novel approach, we discovered a new mesangium-predominant gene termed "megsin." We obtained a full-length cDNA clone of megsin, which coded for a novel 380-amino acid protein. Amino acid homology search revealed that megsin belonged to the serpin (serine protease inhibitor) superfamily. The amino acid sequences in the reactive loop site of megsin showed characteristic features of functional serpins. Northern blot and reverse-transcribed PCR analyses of various tissues and cells demonstrated that megsin was predominantly expressed in human mesangial cells. In situ hybridization studies showed the megsin expression in the mesangium of normal glomeruli, while it increased in the expanded mesangium of glomeruli from patients with IgA nephropathy with the degree of mesangial proliferation. Here we report a new human mesangium-predominant gene that may function as an inhibitory serpin in normal and abnormal biological processes of glomerulus.

Amino Acid Sequence↗

PubMed1998

Human herpesvirus 6 infection as a risk factor for the development of severe drug-induced hypersensitivity syndrome.

BACKGROUND: Drug-induced hypersensitivity syndrome is characterized by a severe, potentially fatal, multiorgan hypersensitivity reaction that usually appears after prolonged exposure to certain drugs. Its delayed onset and clinical resemblance to infectious mononucleosis suggest that underlying viral infections may trigger and activate the disease in susceptible individuals receiving these drugs. OBSERVATIONS: A 60-year-old woman developed an itchy, generalized, erythematous, confluent rash on the 39th day of receiving allopurinol therapy. Even after she discontinued treatment with allopurinol, her skin lesions progressed to severe blistering skin eruption. After the patient started oral prednisone therapy, her skin lesions resolved with desquamation. After complete resolution, rechallenge with allopurinol led to the development of an erythematous eruption. Titers of human herpesvirus 6 IgG antibodies dramatically increased with the development of the eruption. The results of a polymerase chain reaction and in situ hybridization indicated the presence of human herpesvirus 6 in the skin lesions, although human herpesvirus 7 DNA was detected only by in situ hybridization. CONCLUSION: Reactivation of human herpesvirus 6, possibly in concert with human herpesvirus 7, can contribute to the development of a severe drug-induced hypersensitivity syndrome.

DNA, Viral↗

PubMed1998

Severe hypersensitivity syndrome due to sulfasalazine associated with reactivation of human herpesvirus 6.

BACKGROUND: A severe adverse reaction to sulfasalazine therapy has been associated with hypersensitivity syndrome, the clinical features of which are similar to infectious mononucleosis. No serologic evidence of viral infections has been reported with this syndrome; however, human herpesvirus 6 infection has not been specifically investigated, which could cause an infectious mononucleosislike syndrome. OBSERVATIONS: We report 2 cases of hypersensitivity syndrome induced by the use of sulfasalazine. The clinical features of the syndrome appeared 18 and 32 days after administration of sulfasalazine. Clinical signs included a maculopapular rash progressing to exfoliate erythroderma, fever, and lymphadenopathy. Leukocytosis, atypical lymphocytes, liver dysfunction, and renal disturbance were also observed. In 1 patient, human herpesvirus 6 variant B was isolated from peripheral blood mononuclear cells, and in both patients anti-human herpesvirus 6 IgG titers increased considerably. CONCLUSIONS: Two cases of hypersensitivity syndrome due to sulfasalazine use were associated with the reactivation of human herpesvirus 6, which may be a required cause of hypersensitivity syndrome.

Adult↗

PubMed1998

The association of skin diseases with human herpesvirus 8 infection in HIV carriers.

The seroprevalence to Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus type 8 (HHV-8) was surveyed in human immunodeficiency virus type 1 (HIV-1) carriers with or without skin diseases, and also in HIV-1 negative individuals in Thailand. Using an immunofluorescence assay, the seropositive rates to lytic antigens of HHV-8 in HIV-1 carriers with or without skin diseases were 25% and 7.4%, respectively, but none of HIV-1 negative individuals had antibody. The seroprevalence to HHV-8 antigens was high in HIV positive individuals with low CD4/CD8 ratio, suggesting that HHV-8 is reactivated during the immunosuppressive state. Several polypeptides with apparent molecular weights of 34-38,000 and 40,000, which were specific to HHV-8, were identified by the immunoprecipitation test using the seropositive sera. Our results suggested that HHV-8 co-existed with HIV in HIV-1 carriers and the existence of HHV-8 may be associated with clinical features in the skin.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Implication of the glycoxidation and lipoxidation reactions in the pathogenesis of dialysis-related amyloidosis (Review).

Dialysis-related amyloidosis is recognized as a serious bone and joint complication in long-term dialysis patients. Beta2-microglobulin has been demonstrated to be a major constituent of the amyloid fibrils. However, the molecular pathogenesis of this disorder remains unknown. Recent biochemical and immunohistological studies have identified a new modification of beta2-microglobulin in the amyloid fibrils, i.e., the advanced glycation end products (AGEs). AGEs are formed by non-enzymatic glycative and oxidative (glycoxidation) reactions. The levels of AGEs, such as pentosidine and carboxymethyllysine (CML), are elevated in both the plasma proteins and skin collagen of non-diabetic dialysis patients several times more than in normal subjects. The AGE accumulation in uremia cannot be attributed to hyperglycemia, nor simply to their decreased renal clearance. Recently, gathered evidence has suggested that, in uremia, an increase in carbonyl compounds, derived from both carbohydrates and lipids, modifies proteins, leading to the augmentation of the production of not only AGEs, but also the advanced lipoxidation end products (ALEs). Uremia might thus be a state of carbonyl overload with potentially damaging proteins ('carbonyl stress'). Immunohistochemical studies, with antibodies specific to AGEs and ALEs, identified carbonyl stress in long-lived beta2-microglobulin amyloid deposits. Furthermore, proteins modified by carbonyl stress exhibit a variety of biological activities towards several types of cells, which might partially account for dialysis arthropathies.

Amyloid↗

PubMed1997

Prevalence of human herpesvirus-8 in skin lesions.

A putative new herpesvirus, designated Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8) was recently identified in AIDS-related Kaposi's sarcoma. The DNA sequence of the virus is homologous to the gamma-herpesviruses such as herpesvirus Saimiri or Epstein-Barr virus, both of which are tumorigenic, suggesting that this new virus may also be oncogenic. Thus, we determined whether the virus is present in other skin lesions. DNA samples from 118 skin specimens were tested for the HHV-8 sequence by polymerase chain reaction (PCR) and Southern hybridization. The sequences were detected in 13 of 21 samples from Bowen's disease, three of 11 squamous cell carcinomas, three of 11 actinic keratoses, three of seven leucoplakia, one of six from Paget's disease, one of 12 malignant melanoma, one of seven neurofibromas, two of seven chronic dermatites and one of 14 normal skin samples. On sequencing the PCR products, new mutation points were detected. These results suggest that the virus is associated with lesions other than Kaposi's sarcoma and may be more widespread than expected (with a latent level too low to be detected), like the other herpesviruses. Some lesions. e.g. in Bowen's disease or squamous cell carcinoma, may be locally immunosuppressed, allowing the virus to replicate until the copy number is sufficient for detection.

Adolescent↗

PubMed1996

Human herpesvirus 6 induces IL-8 gene expression in human hepatoma cell line, Hep G2.

The infectivity of human herpesvirus 6 (HHV-6) in a human hepatoma cell line, Hep G2 cells, and the effect of HHV-6 on production of inflammatory cytokines in these cells were examined to analyze pathogenesis of HHV-6 in the liver. We demonstrated that Hep G2 cells were susceptible to infection with HHV-6, and produced infectious virus. Moreover, infection of Hep G2 cells by HHV-6 induced the expression of IL-8 mRNA, but not IL-1 beta. The effect on induction of IL-8 gene expression was observed only in Hep G2 cells infected with infectious virus, whereas both heat-inactivated HHV-6 and UV-irradiated HHV-6 did not change the IL-8 mRNA level in these cells. These data suggest that HHV-6 may induce the cytokine-mediated inflammatory response by infecting liver cells, which could result in liver dysfunction in vivo.

Antigens, Viral↗

PubMed1996

Kaposi's sarcoma-associated herpesvirus (KSHV) sequences in premalignant and malignant skin tumors.

The novel herpesvirus-like DNA sequences, which were identified in AIDS-related Kaposi's sarcoma (KS) and designated KS associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8), have been reported to be associated with various forms of KS. Here, we searched for the presence of KSHV sequences in various other skin lesions including premalignant or malignant skin tumors of a total of 69 clinical cases without immunodeficiency due to AIDS or following organ transplantation. Strikingly high rates of detection were obtained for premalignant Bowen's disease and malignant squamous cell carcinoma, accounting for 71.4% and 50%, respectively. A less frequent but as yet high incidence (33.3%) was scored for actinic keratosis, a premalignant epidermal disorder. In contrast, the frequency remained low (16.7%) for another type of proliferative skin lesions of extramammary Paget's disease and non-proliferative skin lesions (dermatitis, morphea, epidermal cyst and scar). These results suggest a close association of KSHV with at least some non-KS malignant and premalignant skin lesions in non-immunocompromised patients.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Prokaryotic expression of an immediate-early gene of human herpesvirus 6 and analysis of its viral antigen expression in human cells.

Segments of an immediate-early (1E) protein (1E03; 958 amino acids (aa)), encoded by clone pSTY03, of human herpesvirus 6 (HHV-6) variant B strain HST were expressed as beta-galactosidase fusion proteins in Escherichia coli. Using Western blot analysis, and the serum of a patient having high titer anti-HHV-6 antibodies, an antigenic region of the IE03 protein was mapped between residues 340 and 505 (pUE03IE-M). The fusion protein expressed in E. coli harboring plasmid pUE03IE-M was purified after electrophoresis in SDS-PAGE, and then immunized in mice to obtain a monospecific antibody. Monospecific antibody raised against the fusion protein reacted with IE03 protein species with apparent molecular weights of 155 and 170 kDa, and was detected as granular fluorescence in nuclei of infected cells by an immunofluorescence antibody test. Furthermore, this antibody reacted only with HHV-6 variant B, but did not react with HHV-6 variant A. The IE03 protein was confirmed to be an IE protein, since the synthesis of this protein was observed in infected cells that were first treated with cycloheximide, which was then replaced with actinomycin D. Further, it was also detected as early as 4 h after infection.

Animals↗

PubMed1996

Possible correlation between Borna disease virus infection and Japanese patients with chronic fatigue syndrome.

Borna disease virus (BDV) is a neurotropic, as yet unclassified, non-segmented, negative-sense, single-strand RNA virus. Natural infection with this virus has been reported to occur in horses and sheep. In addition, antibodies to BDV in plasma or BDV RNA in peripheral blood mononuclear cells (PBMCs) were also found in patients with neuropsychiatric diseases. We describe here the possible link between the patients with chronic fatigue syndrome (CFS) and infection with BDV.

Adult↗

PubMed1994

Glycation of human beta 2-microglobulin in patients with hemodialysis-associated amyloidosis: identification of the glycated sites.

beta 2-Microglobulin (beta 2M) is a major component forming amyloid deposits in patients with hemodialysis-associated amyloidosis (HAA), a serious complication of long-term hemodialysis. Recently, we demonstrated that beta 2M modified with the Maillard reaction is a definite constituent of amyloid deposits in patients with HAA. Our further study demonstrated that this modified beta 2M induces not only chemotaxis of monocytes but also secretion of tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 from macrophages, suggesting the potential link of glycation of beta 2M by the Maillard reaction to the pathogenesis of HAA. The present study was undertaken to identify the glycated site(s) of beta 2M purified from long-term hemodialysis patients as well as beta 2M incubated with glucose in vitro. Borotritide-treated beta 2M was cleaved by endoproteinase Lys-C, and peptides were isolated by reverse-phase high-performance liquid chromatography, followed by amino acid sequence analysis and fast atom bombardment mass spectrometry to identify the glycated site. The glycated sites of beta 2M formed in vivo were found to be almost the same as those of glycated beta 2M in vitro. The primary glycated site was the alpha-amino group of the amino terminal isoleucine. Other minor sites were the epsilon-amino groups of Lys-19, -41, -48, -58, -91, and -94. Computer graphics of the three-dimensional structure of beta 2M suggested that the high specificity for the glycated site at Ile-1 may be explained by its high solvent accessibility and the nearby imidazole group of His-31 as an acid-base catalyst of the Amadori rearrangement.

Adult↗