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Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 883 records · Page 49Linked to original sources
PubMed1984

Visuoperceptual and visuomotor abilities and locus of lesion.

Possible differential effects of laterality and caudality of cerebral lesions on simple visuoperceptual and visuomotor skills were examined. As expected, the right hemisphere lesion group was significantly more impaired than the left hemisphere lesion group. The effects of the caudality of lesion, however, yielded interesting results. While the right posterior group was worse than the right anterior lesion group, as expected, the left posterior lesion group was better than the left anterior lesion group. Our findings points to a possibility that the left hemisphere, especially the anterior region, might not be as silent in processing simple visual stimuli as has been accepted.

Brain Diseases↗
PubMed1984

Kinetics of administered aggregated IgG in rats with passive Heymann's nephritis.

The kinetics of radiolabeled heat-aggregated human IgG (AHIgG125I) were studied in rats with passive Heymann's nephritis (PHN) induced 72 hr previously with decomplemented rabbit antiserum to rat FX1A. Control rats were injected with decomplemented normal rabbit serum (NRS). Following administration of AHIgG125I (40 mg per 100 g of body wt) control and FX1A animals were sacrificed in groups of five each at 2, 4, 8, 16, and 24 hr and kidney, liver, spleen, lung, plasma, and blood cells obtained. 131I-Labeled human serum albumin (HSA131I) was administered prior to sacrifice as a plasma marker. In FX1A rats the following observations were made in comparison with control rats: (1) A decrease in the concentration of AHIgG125I in glomeruli was observed at 2, 4, and 8 hr after administration; (2) a significant increase in clearance reflected by a decrease in the concentration of plasma trichloroacetic acid (TCA)-precipitable radioactivity, and AHIgG125I (greater than 7 S) was present; (3) a significant increase in non-TCA-precipitable radioactivity in plasma and blood cells at most time periods; and (4) decreased concentrations of AHIgG125I in liver and spleen but not lung. The specificity of these observations was supported in separate experiments by the lack of any difference in the plasma levels of TCA-precipitable radioactivity after administration of radiolabeled albumin to FX1A and control rats. Studies in FX1A and control rats revealed no differences in body weight, kidney weight, hematocrit, blood volume, urine output, glomerular filtration rate, renal blood flow, or renal vascular resistance. A slight increase in urinary rat albumin excretion was observed in FX1A rats. The lower values of AHIgG125I observed in plasma, liver, and spleen associated with increased levels of non-TCA-precipitable radioactivity in plasma and blood cells suggest enhanced catabolism of AHIgG125I in FX1A rats, leading to decreased localization within the mesangium.

Animals↗
PubMed1984

Dense intramembranous deposit disease: new pathologic features.

The pathologic and clinical features of 16 patients with dense intramembranous deposit disease are described. By light microscopy nine patients had membranoproliferative glomerulonephritis, five had focal segmental necrotizing glomerulonephritis with segmental epithelial crescents, four of whom also had a prominent tubulointerstitial nephritis, and two had focal segmental mesangial proliferative glomerulonephritis. The patients with membranoproliferative glomerulonephritis and one with focal segmental mesangial proliferative glomerulonephritis had easily recognizable dense intramembranous deposits by optical microscopy. The patients with focal segmental necrotizing glomerulonephritis and one with focal segmental mesangial proliferative glomerulonephritis did not have recognizable peripheral loop dense intramembranous deposits even under oil immersion. In patients with membranoproliferative glomerulonephritis ultrastructural examination revealed extensive capillary wall dense intramembranous deposits. Immunofluorescence revealed diffuse double linear staining along the capillary walls and "mesangial rings" of C3. In the patients with focal segmental necrotizing glomerulonephritis and one with focal segmental mesangial proliferative glomerulonephritis the immunofluorescence study suggested a diagnosis of dense intramembranous deposit disease because of the segmental double linear staining of the capillary walls and "mesangial rings" of C3, but the diagnosis was only established by fine structural analysis where occasional peripheral loop and prominent paramesangial basement membrane dense intramembranous deposits and mesangial nodular deposits were identified. Clinical features prior to biopsy included nephrotic syndrome in eight patients, an acute nephritic syndrome in six patients, and asymptomatic proteinuria and hematuria in two patients. Five of six patients with an acute nephritic presentation had focal segmental necrotizing glomerulonephritis. The acute renal insufficiency in these patients was transitory and appeared to be related to a prominent acute tubulointerstitial nephritis present in four of the biopsy specimens. Depressed serum C3 levels were present in patients with membranoproliferative glomerulonephritis; patients with focal segmental lesions were normocomplementemic. Because of the "atypical" light microscopic features in six of our patients, we support the suggestion that membranoproliferative glomerulonephritis, type II be replaced by the term 'dense intramembranous deposit disease' for this glomerulopathy with variable clinical and histologic features.

Adolescent↗
PubMed1984

Prediction and improvement of protected peptide solubility in organic solvents.

A predictive method of solubility for protected peptide fragments of globular proteins was described. The solubility prediction was performed on the basis of both the randomness of peptide structures in a solid state and the existence of tertiary peptide bonds such as X-Pro and X-(Z) Y bonds, in which X and Y are arbitrary amino acid residues and Z is a suitable protecting group for the X-Y peptide bond. In order to predict the randomness, the coil conformational parameter, Pc, was utilized. Solubility prediction by this method was successfully applied to the two classes of protected peptides composed solely of hydrophobic and of various amino acid residues. The solubility test results also indicate that the protection of peptide bonds at suitable intervals is effective in achieving a remarkable improvement in the solubility of extraordinarily insoluble peptides. Lastly, the strategy for the selection of the coupling routes in the protein syntheses was proposed.

Hydrogen Bonding↗
PubMed1984

Selective binding of IgG4 and other negatively charged plasma proteins in normal and diabetic human kidneys.

Renal tissue from 9 patients with diabetes mellitus (4 with mild and 5 with end-stage disease) and 3 with antiglomerular basement membrane (GBM) nephritis, as well as 5 normal human kidneys, were examined by immunofluorescence microscopy for the presence of plasma proteins of varying isoelectric point (pI). In normal and diabetic kidneys, IgG deposition in basement membranes was restricted to IgG4 (pI 5.5-6.0), the subclass present in lowest concentration in human plasma. IgG1, IgG2, and IgG3 (pI 7.0-9.5) were not detected. In contrast, in anti-GBM nephritis, all four subclasses were present in a linear pattern in GBM. Other plasma proteins of low isoelectric point were detected in basement membranes: albumin (pI 4.9), alpha-1-acid glycoprotein (pI 2.7), amyloid P (pI 3.9-4.8), and alpha-1-antitrypsin (pI 4.5). These studies are consistent with the hypothesis that circulating anionic plasma proteins are electrostatically bound in vivo to positively charged moieties in normal and especially diabetic basement membranes.

Antibodies, Monoclonal↗
PubMed1984

Renal allograft failure due to recurrent dense intramembranous deposit disease.

Dense intramembranous deposit disease (DIDD) almost universally recurs in renal allografts. However, the 29 previously reported cases suggest that recurrent DIDD rarely results in graft failure. We studied the clinical course and renal histology of the 6 patients with DIDD who have received renal allografts here since 1967. All patients had characteristic findings of DIDD in their native kidneys by light, immunofluorescence and electron microscopy. Seven grafts in 4 patients failed and histological evaluation showed that 5 of these allografts in 4 patients were lost due to recurrent disease. They all demonstrated marked mesangial proliferation with crescents but minimal acute interstitial or vascular changes of rejection. Patients with graft failure due to recurrent disease were male and developed recurrent nephrotic syndrome. The 2 patients with rapidly progressive glomerulonephritis (RPGN) in their native kidneys lost the transplanted kidney due to recurrent disease within 1 year. This study suggests that recurrence of DIDD in renal allografts is a more serious problem than previously appreciated, especially in patients with RPGN.

Adolescent↗
PubMed1984

Shwartzman reaction in streptozotocin-induced diabetic rats.

The possibility that experimental diabetes could prepare for the generalized Shwartzman reaction was investigated in female Sprague-Dawley streptozotocin-induced diabetic rats. After 48 hours, 1 week, and 9 weeks of diabetes, the rats were injected with 2 mg/kg of endotoxin, and the animals were sacrificed 2, 4, 8, and 24 hours after endotoxin. Ninety percent of the diabetic animals given endotoxin developed massive glomerular capillary fibrin deposition accompanied by marked decrease in platelet count. The age- and sex-matched nondiabetic control rats had no such changes. This marked susceptibility to endotoxin, previously only reported in pregnant rats, was present as early as 1 week of diabetes. The degree of glycemic control greatly influenced the susceptibility of diabetic rats to the generalized Shwartzman reaction. Only 28% of the diabetic animals given insulin once daily (4.6 +/- 0.3 units, mean +/- SEM) and maintaining a blood glucose level of 269 +/- 19 mg/dl developed glomerular thrombi. In contrast, the diabetic animals that did not receive insulin and had a blood glucose level of 617 +/- 21 mg/dl all developed fibrin thrombi. We conclude that the diabetic state in rats induces a unique susceptibility to the generalized Shwartzman reaction following a single injection of endotoxin, which varies with the severity of the diabetic state. Although the pathogenesis is unclear, this phenomenon may reflect abnormalities in the glomerular capillary wall and/or the coagulation system that may be important in the development of microvascular complications. Furthermore, this phenomenon may, in the animal model, mirror the increased risk of the diabetic patient to intravascular coagulation with bacterial sepsis.

Animals↗
PubMed1983

Dopamine- and cholecystokinin-containing neurons of the crossed mesostriatal projection.

The projection of the substantia nigra-ventral tegmental area (SN-VTA) to the ipsilateral and contralateral caudate-putamen was studied with double-labeling fluorescence techniques in the albino rat. By combining glyoxylic acid histofluorescence with retrograde fluorescence tracers, we were able to determine that 93% of the minor (1-2%) contralateral mesostriatal pathway is catecholaminergic. In addition, combined immunofluorescence and retrograde fluorescence tracer studies showed that 50% of the crossed mesostriatal pathway also arises from cholecystokinin-containing neurons. These results provide evidence for crossed catecholamine- and peptide-containing pathways in the mesostriatal system which is part of the 'prefrontal system' that links the prefrontal cortex through the caudate-putamen, with the thalamus and tectum of each hemisphere.

Animals↗
PubMed1983

Experimental IgA nephropathy in bile duct ligated rats.

Polymeric IgA and polymeric IgA-containing immune complexes are transported from blood to bile through hepatocyte-bound secretory component. In order to investigate interruption of this transport and its effect on the glomerulus, Sprague-Dawley rats underwent bile duct ligation. Renal tissue obtained at the time of sacrifice was stained by immunofluorescent techniques with antibodies to IgG, IgM, and IgA, and secretory component (SC) and C3. A progressive selective increase in the staining intensity of the glomerular mesangium was observed for IgA, C3, and SC in bile duct ligated rats. These changes were paralleled by a rise in serum IgA and C3. These findings are consistent with the view that glomerular deposition of IgA, C3, and SC in bile duct ligated rats may result from impairment of normal handling of polymeric IgA and polymeric IgA-containing immune complexes.

Animals↗
PubMed1983

Absence of Goodpasture's antigen in male patients with familial nephritis.

The presence of Goodpasture's (GP) antigen in the glomerular basement membrane (GBM) of the kidney was evaluated by indirect immunofluorescence in nine patients with familial nephritis from five kindreds. The GP antigen was not detected in seven males but was present in an affected sister and mother, an unaffected brother, and 13 normal controls. The specificity of this finding in affected males is supported by the persistence of other GBM antigens identified by monoclonal antibodies. The lack of GP antigen in affected males and its persistence in related females with the disease suggests a possible X-linked dominant mode of inheritance. We propose that the absence of GP antigen leads to severe disease in the male, whereas its presence in related females is associated with mild disease.

Anti-Glomerular Basement Membrane Disease↗
PubMed1983

Electrical impedance imaging of the thorax.

In this paper, we propose to develop a new imaging technology, computerized impedance tomography (CIT) for imaging the thorax. Our study involves reconstructing images of thoracic transverse plane impedance distributions noninvasively and nondestructively and exploring the potential of CIT. We overcome the reconstruction problem due to nonlinear and nonplanar current paths in impedance imaging by solving Laplace's equation numerically for every iteration and by using a new back-projection algorithm to modify the impedance profile. We discuss advantages and disadvantages associated with impedance imaging, the computer model, and back-projection algorithms used in reconstructing impedance images. We present reconstructed impedance images with 8 projection angles and different projection methods. We identify important variables affecting the quality of reconstructed images, and discuss the resolution and accuracy of this imaging technique. We summarize numerical aspects, computer requirement, and limitations of impedance imaging. We also discuss the future of impedance imaging.

Computers↗
PubMed1983

Phagocytosis of filaments of Escherichia coli produced with mezlocillin.

The phagocytosis of filaments of Escherichia coli produced with mezlocillin differs from the phagocytosis of normal bacilli in that pseudopods are employed for bacilli, but the entire body of the polymorphonuclear cell (PMN) participates in the engulfment of a filament. A single PMN was observed phagocytizing one or more filaments 20-50 micron long. The mass of a filament is about ten times larger than the mass of a bacillus. When equal bacterial mass, one filament or 10 bacilli, is exposed to PMNs comparable bacterial killing results after 2-3 h of incubation.

Blood Bactericidal Activity↗
PubMed1983

Neoantigen of the polymerized ninth component of complement. Characterization of a monoclonal antibody and immunohistochemical localization in renal disease.

A monoclonal antibody to a neoantigen of the C9 portion of the membrane attack complex (MAC) of human complement has been developed and characterized. The distribution of this neoantigen was assessed by indirect immunofluorescence microscopy in nephritic and nonnephritic renal diseases. The antibody (Poly C9-MA) reacted on enzyme-linked immunosorbent assay (ELISA) with a determinant in complement-activated serum that was undetectable in normal human serum (NHS). Zymosan particles incubated in NHS had positive immunofluorescent staining with Poly C9-MA; however, binding of Poly C9-MA was not observed with zymosan particles incubated in sera deficient in individual complement components C3, C5, C6, C7, C8, or C9. Reconstitution of C9-deficient sera with purified C9 restored the fluorescence with Poly C9-MA. Poly C9-MA reacted positively by ELISA in a dose-dependent manner with purified MC5b-9 solubilized from membranes of antibody-coated sheep erythrocytes treated with NHS but not with intermediate complement complexes. Poly C9-MA also reacted in a dose-dependent manner on ELISA and in a radioimmunoassay with polymerized C9 (37 degrees C, 64 h) (poly C9) but not with monomeric C9. Increasing amounts of either unlabeled poly C9 or purified MC5b-9 inhibited the 125I-poly C9 RIA in an identical manner. These studies demonstrate that Poly C9-MA recognizes a neoantigen of C9 common to both the MAC and to poly C9. By immunofluorescence, Poly C9-MA reacted minimally with normal kidney tissue in juxtaglomerular loci, the mesangial stalk, and vessel walls. Poly C9-MA stained kidney tissue from patients with glomerulonephritis in a pattern similar to that seen with polyclonal anti-human C3. In tissue from patients with nonnephritic renal disease--diabetes, hypertension, and obstructive uropathy--Poly C9-MA was strongly reactive in the mesangial stalk and juxtaglomerular regions, tubular basement membranes, and vascular walls. Poly C9-MA binding was especially prominent in areas of advanced tissue injury. Poly C9-MA frequently stained loci where C3 was either minimally present or absent. These studies provide strong evidence for complement activation not only in nephritic but also in nonnephritic renal diseases.

Adult↗
PubMed1983

Prevention of the generalized Shwartzman reaction in pregnant rats by prostacyclin infusion.

The effects of prostacyclin infusion on endotoxin-induced generalized Shwartzman reaction were studied in pregnant rats. Four hours after administration of Escherichia coli endotoxin (0.4 mg) to pregnant rats on the 20th day of gestation, fibrin and platelet thrombi were observed in 72% of the animals. These findings were associated with a decrease in renal blood flow and glomerular filtration rate from 7.0 to 0.7 and 0.8 +/- 0.1 to 2.6 +/- 0.4 and 0.2 +/- 0.8 ml/minute, respectively (p less than 0.0001 and less than 0.05) and a decrease in platelet count (p less than 0.05). The infusion of prostacyclin, at a mean dose of 57 ng/kg/minute prior to and after administration of endotoxin strikingly inhibited the development of fibrin and platelet thrombi in glomerular capillaries (p less than 0.001). Despite hemodynamic changes which were similar to those in control animals, renal blood flow and glomerular filtration rate decreased from 7.2 +/- 0.2 and 0.9 to 2.9 +/- 0.03 and 0.3 +/- 0.1 ml/minute, respectively (p less than 0.001 and less than 0.025). In addition, the mean blood pressure decreased from 118 +/- 3.8 to 86 +/- 3.7 mm Hg (p less than 0.025), whereas the platelet count remained normal. We conclude that prostacyclin infusion prior to endotoxin administration significantly inhibits endotoxin-induced generalized Shwartzman reaction in pregnant rats.

Animals↗
PubMed1983

Recognition of Staphylococcus aureus by human phagocytes. Signals and disguises of the bacterial surface.

Phagocytic cells provide the host its major defense against invasive Staphylococcus aureus, and the staphylococcal surface, by its influence on phagocyte recognition, is a primary determinant of the function of these cells. The peptidoglycan component of the cell wall plays a key role in both opsonic and chemotactic recognition, mediated by IgG, C3b, and C5a, respectively. While cell wall protein A inhibits opsonic recognition by polymorphonuclear leukocytes, it promotes an opsonin-independent mechanism of phagocytosis by human macrophages which possess cytophilic IgG. By masking cell wall-associated opsonic molecules, capsular polysaccharides inhibit recognition, a phenomenon that is overcome by specific anti-capsular antibodies. It is proposed that impaired phagocyte recognition is a basic element in the pathogenesis of staphylococcal endocarditis, and progress in the prevention and treatment of this infection may depend on understanding the basis for this host defense defect.

Animals↗
PubMed1983

Phospholipid dependence of the Hymenolepis diminuta mitochondrial NADPH:NAD transhydrogenase.

The mitochondrial, membrane-associated, nonenergy -linked NADPH:NAD transhydrogenase of adult Hymenolepis diminuta exhibited a phospholipid dependence. This lipid dependence was suggested when mitochondrial membranes were subjected to organic solvent or phospholipase treatments. Although hexane extraction of lyophilized membranes enhanced transhydrogenase activity, subsequent aqueous acetone extraction significantly inhibited the transhydrogenase. An acetone/water-dependent extraction of phospholipids was reflected in the phosphorus content of released material. Incubation of mitochondrial membranes with phospholipase A2 or C markedly reduced transhydrogenase activity, and phospholipase A2 treatment resulted in the greater reduction in activity. The mitochondrial, membrane-associated, NADH-utilizing oxidase and fumarate reductase activities were diminished significantly by hexane as well as phospholipase treatments. Phospholipase A2 caused the greater inhibition of the NADH-utilizing systems. Thus, in contrast to the transhydrogenase, neutral lipids and phospholipids apparently were required by the electron transport-coupled activities. The transhydrogenase activity of organic solvent- or phospholipase-treated membranes was not stimulated effectively by phospholipid addition. However, phospholipid-dependent stimulation of transhydrogenase was accomplished employing a partially lipid-depleted preparation of the enzyme obtained by detergent treatment and ammonium sulfate precipitation. Of the phospholipids tested, only phosphatidylcholine significantly stimulated transhydrogenase activity. The stimulation noted with phosphatidylcholine was not duplicated by cholate or deoxycholate.

Animals↗