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Biomedical subjects

K Iwahara

Publications and source records attributed to K Iwahara.

At least 19 recordsLinked to original sources
PubMed2001

Tryptophan glycoconjugate as a novel marker of renal function.

PURPOSE: Neither serum creatinine concentration nor creatinine clearance assess renal function accurately. Serum creatinine concentration is affected by muscle mass, and the creatinine clearance overestimates the glomerular filtration rate because of tubular secretion of creatinine. The present study was designed to determine whether serum concentrations of 2-(alpha-mannopyranosyl)-L-tryptophan (MPT), a tryptophan glycoconjugate, can be used as a marker of renal function. METHODS: Clearances of MPT and of inulin were compared in normal rats and in rats with cisplatin-induced acute renal failure. We also compared the clearances of MPT and of creatinine with inulin clearance in 25 patients with chronic renal disease. Serum concentrations of MPT and creatinine as a function of MPT clearance were determined in 108 patients with chronic renal disease. RESULTS: There was strong linear correlation between clearances of MPT and inulin in rats (r = 0.97) and humans (r = 0.87), indicating that renal handling of MPT is similar to that of inulin. In humans, linear regression analyses indicated that MPT was a better indicator of inulin clearance than was creatinine clearance. At the same level of renal function, serum creatinine concentrations tended to be lower in patients with less muscle mass (as indicated by a urinary creatinine excretion <1,000 mg in 24 hours) than in those who excreted >1,000 mg in 24 hours, whereas serum MPT concentrations were not affected by creatinine excretion. CONCLUSION: MPT clearance can replace inulin clearance in the clinical setting. The serum MPT concentration is an accurate measure of renal function even in patients with diminished muscle mass, and thus is a better indicator of renal function than is the serum creatinine concentration.

Acute Kidney Injury↗
PubMed2001

Purification and comparison of triosephosphate isomerases from ammonia-oxidizing bacteria isolated from terrestrial and marine environments.

Triosephosphate isomerases [TIMs, EC 5.3.1.1] were purified from two ammonia-oxidizing bacteria: Nitrosomonas sp. K1 (K1), Nitrosomonas sp. TNO632 (TNO). The molecular masses of the native enzymes were estimated to be about 53.6 (K1-TIM) and 51.9 kDa (TNO-TIM) by gel filtration, whereas SDS-PAGE produced one band for each enzyme with M(r) values of 27.1 (K1-TIM) and 26.4 kDa (TNO-TIM), respectively, suggesting that the enzymes consist of identical subunits. The apparent K(m) for d-glyceraldehyde-3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) were about 1.19 and 4.78 mM (K1-TIM), and 0.41 and 6.01 mM (TNO-TIM), respectively. The two TIMs had different pH-activity curves with an optimum pH range of 6.5 (K1-TIM) and 8.0 (TNO-TIM). The temperature optima of K1-TIM and TNO-TIM were 50-60 and 60-65 degrees C, respectively. Both enzymes were strongly inhibited by 5,5'-ditiobis at 1.0 mM. The N-terminal amino acid sequences of K1-TIM and TNO-TIM were MRAGFVAGNWKMHG (K1-TIM) and MVRTGLVAGNWKMNG (TNO-TIM). A homology of 74.1% was observed between K1-TIM and TNO-TIM.

Journal Article↗
PubMed2000

Polymerization of guaiacol by lignin-degrading manganese peroxidase from Bjerkandera adusta in aqueous organic solvents.

Lignin-degrading manganese (II) peroxidase (MnP) purified from the culture of a wood-rotting basidiomycete, Bjerkandera adusta, was used in the polymerization of guaiacol. MnP was found to catalyze polymerization of guaiacol in 50% aqueous acetone, dimethyl formamide, methanol, ethanol, dioxane, acetonitrile, ethylene glycol and methylcellosolve. Maximum yield of polyguaiacol was achieved in 50% aqueous acetone. The weight average molecular weight (Mw) of the polymer was estimated to be 30,300 by gel permeation chromatography. However, matrix-assisted laser desorption ionization time of flight mass spectroscopy (MALDI-TOF-MS) analysis gave a more reliable Mw of 1,690. IR, 13C-NMR, MALDI-TOF-MS and pyrolysis GC-MS analyses showed the presence of C-C and C-O linkages and quinone structure in polyguaiacol. It was also indicated that polyguaiacol has a methoxy-phenyl group as the terminal moiety. This suggests that polyguaiacol is a branched polymer in which guaiacol units are cross-linked at the phenolic group. Thermal gravimetric and differential scanning calorimetric analyses were also carried out. MnP also catalyzed the polymerization of o-cresol, 2,6-dimethoxyphenol and other phenolic compounds and aromatic amines. Mw of these polymers ranged from around 1,000 to 1,500.

Basidiomycota↗
PubMed1998

Electromyographic investigation of chin cup therapy in Class III malocclusion.

Electromyographic activity was evaluated in 20 patients (10 girls and 10 boys, mean age 10 years) with Class III malocclusion who were treated with a chin cup appliance. The posttreatment data were obtained at the end of phase 1 chin cup treatment when the anterior crossbite had been corrected. EMG activity of the masseter and temporal muscles for each subject were studied during unilateral chewing using the following parameters: mean cumulative voltage (MCV), mean maximum peak voltage (MMPV), and rotational direction of the differential lissajous EMG (DL-EMG). The ANB angle improved from -1.0 degree (mean) to 0 degree. The electromyographic study revealed a decrease in masseter muscle activity on both the working (chewing) and balancing sides, with no improvement in the coordination of bilateral masseter and anterior temporal muscles.

Adolescent↗
PubMed1998

Congenital localized multiple fibromatosis: a case report.

Clinical, histopathologic and electronmicroscopic findings in a case of congenital localized multiple fibromatosis of interscapular region are presented. This 10 year-old Japanese girl developed this lesion since she was 3 weeks old, metastases have never been observed. The histological and electron-microscopic features point to the hamartomous origin of this tumor with partial differentiation of its cells towards myofibroblasts and atypical fibroblasts. The differential diagnosis from other soft tissue tumors in infancy and early childhood is discussed.

Biopsy, Needle↗
PubMed1994

A hydrophilic tetrahydro-beta-carboline in human urine.

A substance that exhibited a tryptophan-like fluorescence peak at 354 nm on excitation at 295 nm at neutral pH was isolated from human urine. This compound was determined by visible-light absorption spectroscopy, fluorescence spectroscopy, 1H and 13C NMR spectroscopies, and FAB-MS to be 1-(1',2',3',4',5'-pentahydroxypentyl)-1,2,3,4-tetrahydro-2-carboli ne-3- carboxylic acid. This compound, named tetrahydropentoxyline, is a new type of hydrophilic tetrahydro-beta-carboline, and its elution position was between those of 4-pyridoxic acid and kynurenic acid on C18 reversed-phase HPLC. The amount of tetrahydropentoxyline excreted in the urine of normal subjects [n = 21; age, 45 (SD 20) years] was about 5.2 (SD 1.0) mg per day.

Carbolines↗
PubMed1992

Keratoderma hereditaria mutilans. Etretinate treatment and electron microscope studies.

Keratoderma hereditaria mutilans is a rare inherited cornification disorder characterized by hyperkeratosis of palms and soles with a characteristic "honey-comb" appearance, keratotic constriction furrows of one or more digits (pseudo-ainhum) and threatening spontaneous amputation. Approximately 30 cases have been reported, but the ultrastructural features have not been well characterized. In this article, we describe the clinical, histologic, and ultrastructural findings in our patient. A biopsy specimen taken before treatment with etretinate showed hyperkeratosis with a well-preserved granular layer and acanthosis. Ultrastructural examination disclosed that the spinous cells and granular cells contained marked swollen mitochondria, many desmosomes, and that corneocytes contained many membrane coating granules (MCG) and lipid like vacuoles. After initiation of treatment, considerable clinical improvement was observed, but without significant histologic modification. The principal post-treatment ultrastructural changes were the reduction of mitochondrial swelling in spinous and granular cells and the reduction in the number of MCG in corneocytes. The intercellular spaces showed increased amounts of fine and coarse granular substances. Stimulation of Langerhans cells was observed. Marginal band formation occurred normally after treatment.

Adult↗
PubMed1988

Vulvitis circumscripta plasmacellularis treated successfully with interferon alpha.

A 74-year-old woman with vulvitis circumscripta plasmacellularis was successfully treated with intralesional injections of interferon alpha. Although the patient had been previously treated unsuccessfully for 5 years with topical administration of a potent corticosteroid, with cryotherapy, and with surgical procedures, the disease continually recurred. A course of interferon alpha resulted in a significant clinical improvement of the lesions, a histologically verified decrease of plasma cell infiltrate, and the disappearance of the antigen of herpes simplex virus that had been detected before treatment by direct immunofluorescence staining of the lesion. This clinical course demonstrates the effectiveness of local injections of interferon alpha into those lesions with vulvitis circumscripta plasmacellularis that did not previously respond to conventional therapy. Therefore an implication exists that herpes simplex virus infection may be one of the factors involved in the pathogenesis of this disease.

Aged↗
PubMed1986

Lactate dehydrogenase inhibition by immunoglobulin G in human serum.

Low lactate dehydrogenase (LD; EC 1.1.1.27) activity and an abnormal LD pattern in electrophoretograms of LD isoenzymes in the sera of two patients were caused by inhibition of LD by immunoglobulin G. One of these showed inhibitor activity in the serum upon direct analysis, while the other showed activity only after the immunoglobulin was stripped from the LD. As judged from the LD isoenzyme patterns in serum, the LD inhibitor appeared to act against M subunits. However, quantification of binding affinities to each isolated isoenzyme showed that the LD inhibitor had a stronger effect on LD isoenzymes 2 and 3 (H3M1 and H2M2, respectively).

Aged↗
PubMed1984

T-cell subsets and nuclear contour index of skin-infiltrating T-cells in cutaneous T-cell lymphoma.

Cases of cutaneous T-cell lymphomas including Sézary syndrome were used to evaluate nuclear contour index (NCI), nuclear cytoplasmic ratio (N/C), and helper/suppressor T-cell ratio. It was found that: (1) the average NCI measured in pan-T-cell monoclonal antibody positive cells (N = 100) is higher than that measured in non-T-cells (N = 100) in the same lesion; (2) NCI increased from erythematous stage to tumor or Sézary stage as disease process advances; (3) N/C was not significantly increased with disease process and did not correlate with NCI; (4) suppressor T-cells were significantly increased in early stages of the disease, whereas helper T-cells were dominant in late stage lesions; and (5) the majority of tumor cell infiltrating into the epidermis were helper T-cells in all stages. In control specimens from chronic and acute skin conditions in which lymphocytic infiltration is seen, cells with NCI greater than 6.5 did not exceed 20%. It is concluded that if 25% or more cells in the lesion have NCI greater than 6.5 in pan-T-monoclonal antibody positive cells, the diagnosis of CTCL is very likely. Varying numbers of OKT6 positive cells (Langerhans' cell, thymocyte) were admixed in the dermis of all cases, and had no significant correlation with the stages.

Aged↗
PubMed1983

Immunoelectron microscopy related to T-cell monoclonal surface antigen in mycosis fungoides.

For the purpose of diagnosing and staging cutaneous T-cell lymphoma, the nuclear contour index and subsets of T-cells in the lesions were studied. Nuclear contour index measured in T-cells identified precisely with monoclonal pan-T antibody was found to be higher than nuclear contour index measured in T-cell-like cells with significant nuclear convolution. Nuclear contour index increased as the disease progressed from erythematous to tumor stage or to the Sézary syndrome. The relative ratio of suppressor cytotoxic T-cells to helper T-cells was higher in the early rather than late stage of cutaneous T-cell lymphoma.

Antibodies, Monoclonal↗