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Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 865 records · Page 48Linked to original sources

Amyloid P component is not present in the glomerular basement membrane in Alport-type hereditary nephritis.

Serum amyloid P component (SAP) is a normal plasma glycoprotein immunochemically indistinguishable from amyloid P, a glycoprotein found in all tissue amyloid deposits. SAP has also been shown to be a constituent of normal glomerular basement membrane (GBM). In this study the authors discovered a unique association between SAP and Goodpasture (GP) antigen. In those patients whose GBM lack GP antigen (those with Alport-type hereditary nephritis) SAP is also uniformly absent. Although the relationship between these two components is unknown, this association may provide clues to the abnormality of GBM in Alport-type hereditary nephritis.

Anti-Glomerular Basement Membrane Disease↗

Amino acid sequence similarity between spinach chloroplast and mammalian gluconeogenic fructose-1,6-bisphosphatase.

Chloroplast fructose-1,6-bisphosphatase is an essential enzyme in the photosynthetic pathway of carbon dioxide fixation into sugars and the properties of this enzyme are clearly distinct from cytosolic gluconeogenic fructose-1,6-bisphosphatase. Light-dependent activation via a ferredoxin/thioredoxin system and insensitivity to inhibition by AMP are unique characteristics of the chloroplast enzyme. In the present study, purified spinach chloroplast fructose-1,6-bisphosphatase was reduced, S-carboxymethylated with iodoacetic acid, and cleaved with either cyanogen bromide or trypsin. The resulting peptides were purified by reversed-phase high performance liquid chromatography. Automated Edman degradation of some of the purified peptides showed amino acid sequences highly homologous to residues 72-86, 180-199, and 277-319 of pig kidney fructose-1,6-bisphosphatase. These findings suggest a common evolutionary origin for mammalian gluconeogenic and chloroplast fructose-1,6-bisphosphatase, enzymes catalyzing the same reaction but having different functions and modes of regulation.

Amino Acid Sequence↗

Radioimmunoassay of the attack complex of complement in serum from patients with systemic lupus erythematosus.

We developed a radioimmunoassay to measure the attack complex of complement (SC5b-9) in serum from patients with systemic lupus erythematosus. The radioimmunoassay used a monoclonal antibody to an antigen of C9, which is absent from native C9 but present on SC5b-9. SC5b-9 was detectable in 13 of 63 normal subjects, with a mean value of 0.5 unit (range, 0 to 4.8), and elevated in 13 of 14 patients with active lupus. Analysis of 108 samples from the patients with lupus revealed a mean value of 10.1 units (range, 0 to 35) when the disease was active and 1.0 unit (range, 0 to 433) when it was clinically stable. SC5b-9 was a more sensitive measure of disease activity than C3, C4, or CH50; its specificity was equivalent to that of C3 and C4. SC5b-9 was elevated in serum from 6 of 49 patients with other forms of glomerulonephritis. Our study documents the presence of SC5b-9 in abnormal serum and correlates its elevation with clinical disease activity in patients with active systemic lupus erythematosus.

Adolescent↗

Human T-cell leukemia virus type II: primary structure analysis of the major internal protein, p24 and the nucleic acid binding protein, p15.

The 24,000-molecular-weight major internal protein (p24) and the 15,000-molecular-weight nucleic acid binding protein (p15) of human T-cell leukemia virus type II (HTLV-II) were subjected to amino acid composition and amino-terminal amino acid sequence analysis. A comparison of amino acid composition of p24 and p15 of HTLV-II with those of the analogous proteins of HTLV-I revealed that these two proteins share overall similarity. Further, alignment of the amino-terminal amino acid sequence for the first 27 residues of p24 and 34 residues of p15 from HTLV-II showed extensive sequence homology with analogous proteins of HTLV-I. These data suggest that although disease associated with HTLV-I is malignant T-cell leukemia and that associated with HTLV-II is a relatively benign variant of hairy-cell leukemia, HTLV-I and HTLV-II are closely related to each other, at least in their gag-gene-encoded sequences.

Amino Acid Sequence↗

Reduction and oxidation of cytochrome C by Hymenolepis diminuta (Cestoda) mitochondria.

Mitochondrial membranes of adult Hymenolepis diminuta catalyzed inhibitor-sensitive ferricytochrome c reduction. Cytochrome c reductase activity was noted when NAD(P)H or succinate served as the reductant with the NADH-coupled reaction being most prominent. Both rotenone-sensitive and -insensitive reduced pyridine nucleotide-coupled activities were apparent. Ferrocytochrome c oxidase activity also was catalyzed by H. diminuta mitochondrial membranes and this reaction was sensitive to azide and cyanide. A cytochrome c peroxidase activity was associated primarily with the mitochondrial soluble fraction of adult H. diminuta. The possibility that the activities observed may contribute to the elimination of peroxide in the helminth system is considered.

Animals↗

Human T-cell lymphotropic virus type III: immunologic characterization and primary structure analysis of the major internal protein, p24.

The major internal structural protein of human T-cell lymphotropic virus type III (HTLV-III), a virus etiologically implicated in acquired immunodeficiency syndrome (AIDS), was purified to homogeneity. This 24,000-molecular-weight protein (p24) was shown to lack immunologic cross-reacting antigenic determinants shared by other known retroviruses, including HTLV-I and HTLV-II, with the exception of equine infectious anemia virus (EIAV). A broadly reactive competition immunoassay was developed in which antiserum to EIAV was used to precipitate 125I-labeled HTLV-III p24. Although the major structural proteins of HTLV-III and EIAV competed in this assay, other type B, C, and D retroviral proteins lacked detectable reactivity. Thus, HTLV-III is more related to EIAV than to any other retroviruses. That the HTLV-III isolate is very distinct from HTLV-I and HTLV-II was further confirmed by the amino acid compositions of the major internal antigens of all three isolates. Moreover, comparison of the amino-terminal amino acid sequence of HTLV-III p24 with analogous sequences for HTLV-I and HTLV-II p24 showed that these proteins do not share significant sequence homology. In an attempt to evaluate immune response in individuals exposed to HTLV-III, sera from AIDS and lymphadenopathy syndrome patients as well as from clinically normal blood donor controls were tested for antibodies to HTLV-III p24. The results showed that sera from 93% of lymphadenopathy syndrome patients and 73% of AIDS patients exhibited high-titered antibodies to HTLV-III p24. In contrast, none of the normal control sera showed detectable reactivity to HTLV-III p24.

Acquired Immunodeficiency Syndrome↗

Colon adenocarcinoma-associated nuclear antigens.

Colon adenocarcinoma-associated chromosomal nonhistone proteins were determined in rat colon adenocarcinoma chromatin and in colon chromatin of Sprague-Dawley rats treated with 1,2-dimethylhydrazine (DMH) by the enzyme-linked immunosorbent assay method. The specific nuclear proteins are tissue-specific oncofetal antigens. They were also detected in fetal rat colon chromatin but not in adult rat colon chromatin. The specific tumor-associated nonhistone proteins were identified by immunoblot. The molecular weight ranges of these proteins were 79,000-89,000 and 40,000-56,000 daltons. Administration of DMH to Sprague-Dawley rats induced colon tumor and colon tumor-associated nonhistone proteins in the chromatin. However, DMH failed to induce colon tumor and tumor-associated nonhistone proteins in Lobund-Wistar rats.

Adenocarcinoma↗

Release of arachidonate from membrane phospholipids in cultured neonatal rat myocardial cells during adenosine triphosphate depletion. Correlation with the progression of cell injury.

The present study utilized a cultured myocardial cell model to evaluate the relationship between the release of arachidonate from membrane phospholipids, and the progression of cell injury during ATP depletion. High-energy phosphate depletion was induced by incubating cultured neonatal rat myocardial cells with various combinations of metabolic inhibitors (deoxyglucose, oligomycin, cyanide, and iodoacetate). Phospholipid degradation was assessed by the release of radiolabeled arachidonate from membrane phospholipids. In this model, the current study demonstrates that (a) cultured myocardial cells display a time-dependent progression of cell injury during ATP depletion; (b) the morphologic patterns of mild and severe cell injury in the cultured cells are similar to those found in intact ischemic canine myocardial models; (c) cultured myocardial cells release arachidonate from membrane phospholipids during ATP depletion; and (d) using two separate combinations of metabolic inhibitors, there is a correlation between the release of arachidonate, the development of severe cellular and sarcolemmal damage, the release of creatine kinase into the extracellular medium, and the loss of the ability of the myocardial cells to regenerate ATP when the metabolic inhibitors are removed. Thus, the present results suggest that during ATP depletion, in cultured neonatal rat myocardial cells, the release of arachidonate from myocardial membrane phospholipids is linked to the development of membrane defects and the associated loss of cell viability.

Adenosine Triphosphate↗

Ultrastructure of staphylococci in respiratory infections treated with nafcillin.

A patient with a pleural effusion containing Staphylococcus aureus was treated with nafcillin. Another patient with bilateral upper lobe infiltrates which grew S. aureus from a catheter inserted through a fiberoptic bronchoscope into the lesion was also treated with nafcillin. Electron microscopy of organisms grown while the patients were receiving nafcillin showed staphylococci which were twice as large as normal and contained multiple cross-walls and normal peripheral cell walls. Such abnormal staphylococci result from exposure to subminimum inhibitory concentrations of beta-lactam antibiotics.

Adult↗

Effect of pH on the morphology of Staphylococcus aureus.

Nineteen strains of Staphylococcus aureus (10 sensitive and 9 resistant to oxacillin) were grown for four hours on membranes placed on trypticase soy agar at pH 5, 5.5, 6, 6.5, 7.1, 7.5, 7.8 and 8.3. The morphology was observed by interference phase contrast and by electron microscopy. All strains grown at pH 6 to 7.5 produced cocci of normal size. When grown at pH 5, 5.5, 7.8 and 8.3, however, seven of the oxacillin-resistant strains and seven of the oxacillin-sensitive strains produced bacterial cells 1.5 to 2 micron in diameter. These cells consist of a cluster of staphylococci held together by multiple thick cross walls. Their structure is similar to that of staphylococci grown in the presence of subminimum inhibitory concentrations of beta-lactam antibiotics, which inhibit autolysis of cross walls. It appears that autolysis of cross walls of S. aureus is also inhibited by a low or a high pH.

Autolysis↗

Visuospatial impairment in Parkinson's disease. Role of perceptual and motor factors.

We investigated the role of perceptual and motor factors in visuospatial impairment in 30 patients with Parkinson's disease (PD) and 30 matched controls. All subjects were administered visuospatial tests, which included "visuoperceptual" tasks, requiring minimal motor responses, and "visuomotor" tasks. The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment. Patients in stage 3 of the disease tended to show the greatest impairment. Those in stage 1 (unilateral symptoms), however, tended to show more impairment than those in stage 2.

Aged↗