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Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 667 records · Page 37Linked to original sources
PubMed1994

Application of electron microscopic immunocytochemistry to the human kidney: distribution of type IV and type VI collagen in normal human kidney.

We used immunogold electron microscopic (IEM) techniques with periodate-lysine-paraformaldehyde-fixed and Lowicryl-embedded or cryopreserved tissues to study the distribution of alpha 1(IV) and alpha 3(IV) chains of Types IV and VI collagen in glomerular basement membrane (GBM) and mesangial matrix of glomeruli in normal human kidneys. Monoclonal antibodies to alpha 1(IV) and alpha 3(IV) collagen chains and Type VI collagen could be detected only with cryoultramicrotomy, whereas polyclonal anti-Type IV collagen antibody was detectable in Lowicryl-embedded tissue. Ultrastructural detail was better preserved in the Lowicryl-embedded tissue. IEM labeling provided more detailed information as to the site-specific array of these extracellular matrix molecules in glomeruli than did immunofluorescent microscopy. The labeling of alpha 1(IV) collagen chain was distributed mainly along the endothelial side of glomerular basement membrane and the mesangial matrix. Mesangial GBM was relatively poorly labeled compared with that of mesangial matrix. In contrast, the alpha 3(IV) chain was detected throughout the thickness of the GBM, but there was no labeling of mesangial matrix. Type VI collagen distribution was identical to that of the alpha 1(IV) chain within the glomerulus but was also associated with interstitial collagen fibrils. This study documents and details the heterogeneous distribution of Type IV and VI collagen chains within the normal human glomerulus and provides the framework for the study of these matrix components in human glomerular diseases.

Basement Membrane↗
PubMed1994

Hearing preservation and improvement of auditory brainstem response findings after acoustic neuroma surgery.

Among 9 patients with acoustic neuroma who underwent tumor removal by the middle cranial fossa approach during the past 5 years, 6 were selected for hearing preservation surgery which was successful in 5 cases (83.3%). For the prediction of success in hearing-preservation, factors related to hearing preservation, including preoperative findings of neurotological examination, were analyzed. Postoperative hearing threshold correlated significantly with wave V latency and I-V interpeak latency of preoperative auditory brainstem response (ABR) and the SP/AP ratio of preoperative electrocochleogram and postoperative facial palsy. The size of tumors and preoperative results of speech audiometry did not correlate with hearing results. Postoperative ABR findings were normalized within the observation period from 5 days to 10 months in 3 hearing-preserved patients. Possible mechanisms for improvement of ABR findings after the removal of acoustic neuroma are discussed.

Adult↗
PubMed1994

Measurement of cochlear basilar membrane traveling wave velocity by derived ABR.

Auditory brainstem response (ABR) can be used to measure the basilar membrane traveling wave velocity (TWV). Traveling wave velocity was calculated from the latency difference between wave V of different derived ABR and the cochlear location distance between the appropriate derived band center frequency. The latency of wave V of derived ABR produced by 6 noise-masked ABR using high pass filtered noise and the location of the corresponding cochlear partition (distance from the stapes foot-plate) were measured, and five traveling wave velocities were estimated based on this parameter. Ten subjects with normal hearing, 7 patients with Meniere's disease, and 8 patients with sensorineural hearing loss were used in this study. The traveling wave velocity in the sensorineural hearing loss group was within normal limits at all frequencies, whereas the traveling wave velocity at 8 kHz in the Meniere group greatly exceeded that of the normal and sensorineural hearing loss group.

Acoustic Stimulation↗
PubMed1994

Results of treatment of laryngeal cancer.

Eighty-one laryngeal cancer patients treated at our clinic during the past ten years were studied clinically. The proportion of patients in their sixties was highest and the number of males was much larger than that of females, at a ratio of 15:1. Laryngeal cancer was classified as glottic, supraglottic, and subglottic in 58, 19, and 4 cases, respectively, and glottic cancer patients accounted for more than half of these. The cumulative 5-year survival rate in all patients was 79.6%, and the rates in glottic and supraglottic cancer patients were 82.2% and 83.3%, respectively. Cumulative 5-year survival rates in patients in Stages I, II, III and IV were 83.7%, 83.9%, 83.3%, and 55.5%, respectively. Recurrence after radiotherapy was controlled by salvage operations satisfactorily in Stages I and II, but the prognosis of recurrent cancer was poor for patients in Stages III and IV. A selective review is given.

Adult↗
PubMed1994

Modified method of submucosal turbinectomy: mucosal flap method.

Sixteen patients with nasal obstructions were treated by use of a new technique of submucosal turbinectomy (mucosal flap method) which can reduce a large volume of the turbinate without leaving any mucosal defect. Subjective nasal obstruction showed improvement in all of the cases at 1 month after operation, and objective nasal obstruction examined with rhinomanometry was improved in 13 out of 16 sides of the noses (8 cases). Mucosal flaps were made from the turbinate mucosa facing the common meatus. After excision of the turbinate bone with the mucosa, the bone stump and mucosal defect were covered with the newly repositioned mucosal flap. It is considered that this mucosal flap method can reduce a large volume of the turbinate without leaving any mucosal defect.

Adolescent↗
PubMed1994

[Wegener's granulomatosis--report of four cases including two in patients who died of myocardial infarction].

The prognosis for Wegener's granulomatosis (W-G) is good if it is diagnosed early and a combination of corticosteroids and cytotoxic drugs is given. During the past fourteen years, we were encountered four cases of W-G, three were systemic and one was limited. Of the three patients, with systemic disease, two died of myocardial infarction caused by a delay in diagnosis and one died of fulminant renal and respiratory failure. Only the one patient with a limited form of the disease survived for more than 5 years. We emphasize the importance of early diagnosis with consideration of the systemic features of W-G.

Acute Kidney Injury↗
PubMed1994

Cholesterol synthesis inhibitors inhibit more than cholesterol synthesis.

The beneficial effects of HMG-CoA reductase inhibition in models of progressive glomerular injury may not all be due to reductions in circulating lipoproteins and decreases in glomerular lipoprotein deposition. Indeed, HMG-CoA reductase inhibitors may have direct effects on glomerular mesangial cells that could explain the amelioration of renal injury. Specifically, HMG-CoA reductase inhibitors block the synthesis of isoprenoids that are necessary for mesangial cell proliferation and other important cell functions. Thus, protein isoprenylation may play a critical role in the pathogenesis and treatment of lipid-induced glomerular injury.

Animals↗
PubMed1994

Immunohistologic studies of type IV collagen in anterior lens capsules of patients with Alport syndrome.

BACKGROUND: Alport syndrome is an inherited disorder affecting the kidney, eye and ear arising from mutations in the gene COL4A5, which encodes the alpha 5 chain of type IV collagen. Structural defects of glomerular basement membranes in Alport syndrome are associated in most instances with failure to detect the alpha 3, alpha 4, and alpha 5 chains of type IV collagen as well as the Alport antigen that is identified in normal tissues by a genetically discriminating alloantibody and monoclonal antibody. Anterior lenticonus is an ocular abnormality pathognomic of Alport syndrome that is associated with marked thinning of the anterior lens capsule (ALC). The reactivity of Alport ALC with type IV collagen antibodies has not previously been reported. EXPERIMENTAL DESIGN: ALCs were obtained at the time of cataract extraction from two unrelated males with Alport syndrome and anterior lenticonus, and stained with antibodies against the alpha 1, alpha 2, alpha 3 and alpha 4 chains of type IV collagen, as well as an antibody against the alpha 5 (IV) chain. Controls consisted of ALCs from a normal individual and from a patient with diabetes mellitus. RESULTS: Normal and diabetic ALCs reacted with antibodies against the alpha 1, alpha 2, alpha 3, and alpha 4 chains of type IV collagen and the alpha 5 (IV) chain. In one of the Alport patients, ALC showed no reactivity with antibodies against the alpha 5 (IV) chain and the alpha 3 and alpha 4 chains of type IV collagen. In the second patient, ALC reactivity with these antibodies was preserved. Epidermal basement membranes from this second patient also showed reactivity with antibody against the alpha 5 (IV) chain, unlike most males with Alport syndrome. In both Alport patients, ALCs reacted with antibodies against the alpha 1 (IV) and alpha 2 (IV) chains. CONCLUSIONS: These findings suggest that anterior lenticonus in patients with Alport syndrome may be associated with absence of the alpha 3 and alpha 4 chains of type IV collagen, as well as the alpha 5 (IV) chain, from anterior lens capsule. On the other hand, these chains may be present in Alport patients with anterior lenticonus. The precise structural basis for mechanical weakness of the anterior lens capsule in patients with Alport syndrome remains to be determined.

Basement Membrane↗
PubMed1993

Crystal structure of a yeast TBP/TATA-box complex.

The 2.5 A crystal structure of a TATA-box complex with yeast TBP shows that the eight base pairs of the TATA box bind to the concave surface of TBP by bending towards the major groove with unprecedented severity. This produces a wide open, underwound, shallow minor groove which forms a primarily hydrophobic interface with the entire under-surface of the TBP saddle. The severe bend and a positive writhe radically alter the trajectory of the flanking B-form DNA.

Amino Acid Sequence↗
PubMed1993

fd coat protein structure in membrane environments.

The membrane bound form of bacteriophage fd coat protein has a long hydrophobic membrane spanning helix and a shorter amphipathic helix in the plane of the bilayer. Residues near the N and C termini and in the turn connecting the two helices are mobile. The locations and orientations of the helical secondary structure elements and the protein backbone dynamics were characterized by combining results from multidimensional solution NMR experiments on protein samples in micelles and high resolution solid-state NMR experiments on protein samples in oriented and unoriented lipid bilayers. The coat protein is a monomer in micelles. The secondary structure of the membrane bound form of fd coat protein is very similar to that of the structural form found in the virus particles, since it is nearly all alpha helix. However, the membrane bound form of the protein differs from the structural form of the protein in virus particles in the arrangement of the secondary structure, since the membrane bound form of the protein has two distinct helical domains oriented perpendicular to each other and the structural form of the protein in the virus particles has a nearly continuous helix aligned approximately along the filament axis. In addition, there are substantial differences in the dynamics of residues in the bend between the two helices and near the C terminus, since they are mobile in the membrane bound form of the protein and not in the virus particles. Residues 1 to 5 at the N terminus are highly mobile and unstructured in both the membrane bound and structural forms of the coat protein.

Amides↗
PubMed1993

A G-protein-coupled 130 kDa phospholipase C isozyme, PLC-beta 4, from the particulate fraction of bovine cerebellum.

A 130 kDa PLC isozyme was purified from the particulate fraction of bovine cerebellum. This PLC was recognized by a polyclonal antiserum generated against the purified 97 kDa PLC-beta 4. Reconstitution of the purified 130 kDa PLC with the membranes of C6 Bu-1 cells in the presence of GTP gamma S or AlF4- resulted in PLC activation as well as the association of PLC with the membranes. Both the association and activation were revoked when the membrane was washed with 2 M KCl. The 97 kDa PLC-beta 4 did not associate with membranes. These data suggest that the 130 kDa PLC is the intact form of PLC-beta 4 the activity of which is likely to be regulated by a G-protein on the membrane.

Animals↗
PubMed1993

Protein phosphatases 1, 2A, and 2C are protein histidine phosphatases.

Eukaryotic cellular proteins contain phosphohistidine. To search for protein histidine phosphatases, protein histidine kinase from Saccharomyces cerevisiae was used to phosphorylate histone H4 on histidine at position 75 in the H4 amino acid sequence. Incubation of the phosphorylated histone H4 with either protein phosphatase 1, 2A, or 2C resulted in extensive removal of phosphate from the phosphorylated histone. Thus, protein phosphatases 1, 2A, and 2C are histidine phosphatases as well as serine/threonine phosphatases. Calcium/calmodulin-regulated protein phosphatase (protein phosphatase 2B) did not remove phosphate from phosphohistidine. The histidine phosphatase reaction was tested for a magnesium requirement and effects of inhibitor-1 and okadaic acid. In all cases, the protein phosphatases behaved as they do in their serine/threonine phosphatase activity. Extracts of the yeast, S. cerevisiae, contain protein histidine phosphatase activity. Quantitative measurement of phosphatase activity shows that the activity against phosphohistidine is a major activity of protein phosphatases 1, 2A, and 2C.

Carrier Proteins↗
PubMed1993

Characterization of a rat airway cDNA encoding a mucin-like protein.

The purpose of this study was to isolate airway mucin cDNAs for use in studies of mucin biosynthesis in rat models of human airway disease. To this end, we screened a rat airway cDNA library with the human intestinal mucin cDNA SMUC 41 and obtained 7 positive clones. Preliminary characterization of each of these led us to focus on the clone expressing the 390 bp cDNA RAM 7s. Evidence indicating that RAM 7s encodes part of a rat airway mucin gene is that RAM 7s: (a) hybridizes in plaque lifts to SMUC 41, (b) hybridizes in Northern blots to large, polydisperse transcripts, (c) has a sequence encoding threonine-rich tandem repeats and (d) shows appropriate tissue-specific expression of cognate mRNA. The repetitive peptide encoded by RAM 7s includes five copies of the consensus sequence TTTTIITI. Because this sequence is different from those reported for two cDNAs previously isolated from rat intestinal libraries, we tentatively conclude that RAM 7s encodes part of a previously unidentified rat mucin gene.

Amino Acid Sequence↗
PubMed1993

Binding of ovarian cancer cells to peritoneal mesothelium in vitro is partly mediated by CD44H.

Epithelial cancer of the ovary spreads by implantation of tumor cells onto the mesothelial lining of the peritoneal cavity. We have developed an in vitro binding assay using confluent monolayers of normal peritoneal mesothelial cells in order to assess the role of known adhesion proteins in this process. Cells from normal ovarian surface epithelium and the ovarian cancer cell lines CAOV-3 and SKOV-3 exhibited significant adhesion to mesothelium in vitro (range 33-56% specific binding). Although these cells expressed several adhesion molecules, including CD44 and integrins such as alpha 4 beta 1, alpha 5 beta 1, and alpha v beta 3, only anti-CD44 antibody was capable of inhibiting mesothelial binding (range 42-44% inhibition). Adhesion molecule expression was also determined for fresh ovarian specimens, with CD44 being expressed in 2 of 2 cases of normal ovarian epithelium, 15 of 16 (94%) cases of tissue-derived tumor (from primary sites or peritoneal implants), and only 2 of 8 (25%) cases of free-floating tumor cells from ascites. Three of three CD44-positive cases derived from peritoneal implants exhibited significant mesothelial binding which was partly blocked by anti-CD44 antibody, whereas 2 of 2 CD44-negative cases derived from ascites showed minimal binding. CD44-mediated binding of ovarian cancer cells was determined to be due to recognition of mesothelium-associated hyaluronate, suggesting that the CD44H isoform was involved in this process. Immunoprecipitation of the CD44 species expressed by ovarian cancer cells revealed 2 major bands at 85-90 and 180 kDa, consistent with the known molecular masses of CD44H. These results suggest that CD44H may be an important mediator of ovarian cancer cell implantation and that decreased CD44H expression may be associated with release of cells into the peritoneal space during ascites formation. It is possible that strategies to interfere with CD44H function may result in decreased intraabdominal spread of this highly lethal neoplasm.

Cell Adhesion↗
PubMed1993

Protein phosphatase assay suitable for acid-labile substrates.

A sensitive protein phosphatase assay suitable for acid-labile substrates has been developed. The assay involves incubation of the phosphatase with a 32P-labeled phosphoprotein substrate, quenching the reaction, and then filtering through an ultrafilter that retains substrate and allows the released phosphate to flow through. The released phosphate is counted. The use of a slightly alkaline quenching solution makes the assay suitable for all phosphoamino acids that are stable near physiological pH, including the acid-labile phosphoamino acids. The process is made very convenient by the use of disposable microcon-3 ultrafiltration devices. Radioactive waste is limited to reaction tubes, the microcon-3s, pipette tips, and the scintillation vials and fluid.

Acids↗