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Y Kim

Publications and source records attributed to Y Kim.

At least 739 records · Page 41Linked to original sources
PubMed1992

The pathologic spectrum of the nephropathy associated with alpha 1-antitrypsin deficiency.

To further define the clinicopathologic spectrum and pathogenetic mechanism of the nephropathy associated with alpha 1-antitrypsin (A1AT) deficiency, we evaluated renal specimens from 34 patients with chronic hepatic disease, including 20 with A1AT deficiency (study patients), and correlated these findings with urinalysis evaluation. Glomerular lesions were noted in 79% (15 of 19) of A1AT patients with the PiZZ phenotype, including seven with mesangio-capillary glomerulonephritis (MPGN and focal segmental MPGN), six with mesangial proliferative glomerulonephritis (Mes GN), one with diffuse endocapillary proliferative glomerulonephritis (DPGN), and one with focal segmental mesangial proliferative glomerulonephritis with segmental necrosis (FS Nec GN). One A1AT patient with the PiMZ phenotype did not demonstrate glomerular abnormalities. Focal segmental Mes GN was found in 43% (six of 14) of patients in an age-matched group with chronic hepatic failure unrelated to A1AT deficiency. In nine study patients, glomerular pathology was noted in the presence of a normal urinalysis. Immunofluorescence studies revealed the presence of immunoproteins and the A1AT protein isoelectric forms, PiM and PiZ, in the subendothelial region of glomerular basement membranes in A1AT patients with MPGN, Mes GN, and DPGN. Our results emphasize the heterogeneity of glomerular lesions associated with A1AT deficiency and hepatic disease and the relatively high incidence of MPGN in these children. The presence of abnormal PiZ protein in the subendothelial region of the glomerular basement membrane in A1AT patients with glomerulonephritis suggests a possible role for this protein in the pathogenesis of this lesion.

Adolescent↗
PubMed1992

Single biopsy, tumor kinetic analyses: a comparison of methods and an extension to shorter sampling intervals.

There is emerging and established clinical and laboratory evidence that proliferation of tumor clonogens during radiation therapy can impair local tumor control. The pre-treatment, tumor potential doubling time, T(pot), estimated with in situ bromodeoxyuridine (BrdUrd) labeling, followed by a single biopsy and flow cytometry, may be a predictor of a given tumor's ability to undergo such intra-treatment proliferation. Recent studies have found a strong similarity between T(pot)'s determined in this fashion and the effective doubling times of surviving tumor cells during radiotherapy, as estimated from tumor control versus treatment duration data. Furthermore, several preliminary clinical studies have indicated that T(pot) may be a predictor of outcome, with faster tumors doing worse. Accelerated fractionation might overcome such proliferation, but is more acutely toxic and is unlikely to benefit patients with slowly proliferating tumors. Thus, the BrdUrd/single biopsy method may offer the possibility of selecting between accelerated and conventional or hyperfractionated treatment. Several approaches to the analysis of data generated by this method have been described, but there has been little documentation of the validity of methods in experimental systems, particularly in human experimental tumors. This study explores various analytic methods employed with the BrdUrd, delayed, single-biopsy technique used in determining the potential doubling time, T(pot), of tumors. It compares methods of analysis in three experimental systems and in 40 in situ-labeled human tumors, and proposes a method for shortening the required labeling-biopsy interval to a clinically more convenient range of 3 to 4 hours.

Animals↗
PubMed1992

Vacuolar H(+)-translocating pyrophosphatases: a new category of ion translocase.

The membrane surrounding the central vacuole of plant cells contains an H(+)-translocating ATPase (H(+)-ATPase) and an H(+)-translocating inorganic pyrophosphatase (H(+)-PPase). Both enzymes are abundant and ubiquitous in plants but the H(+)-PPase is unusual in its exclusive use of inorganic pyrophosphate (PPi) as an energy source. The lack of sequence identity between the vacuolar H(+)-PPase and any other characterized ion pump implies a different evolutionary origin for this translocase. The existence of the vacuolar H(+)-PPase, in conjunction with increasing recognition of PPi as a key metabolite in plant systems, necessitates reconsideration of ATP as the primary energy source for membrane transport in plant cells.

Amino Acid Sequence↗
PubMed1992

Distribution of the alpha 1 and alpha 2 chains of collagen IV and of collagens V and VI in Alport syndrome.

We compared the distribution of the alpha 1 and alpha 2 chains of collagen IV and of collagens V and VI in glomeruli of males with Alport syndrome to their distribution in normal glomeruli and glomeruli from patients with non-Alport renal diseases. alpha 1(IV), alpha 2(IV), collagen V and collagen VI are normally restricted to the mesangium and the subendothelial aspect of the glomerular basement membrane (GBM). In contrast, these proteins were present throughout the entire width of the GBM in Alport glomeruli. These alterations were apparent in "early" Alport glomeruli, that is, those exhibiting minimal abnormalities by light microscopy, and they were further accentuated in sclerosing Alport glomeruli. Obsolescent Alport glomeruli, in which the capillary tuft had collapsed and few remaining cell nuclei were present, exhibited nearly complete loss of alpha 1(IV) and alpha 2(IV), like obsolescent glomeruli in non-Alport diseased kidneys. However, the matrix of obsolescent Alport glomeruli stained intensely for collagen V and collagen VI, while these collagen types were not prominent in obsolescent glomeruli of non-Alport diseases kidneys. These observations suggest that the process of glomerulosclerosis in Alport kidneys has attributes unique to this disease. It would also appear that mutations affecting the Alport gene product have secondary effects on the distribution of other GBM constituents.

Adolescent↗
PubMed1992

Analysis of several key active site residues of ricin A chain by mutagenesis and X-ray crystallography.

Active site residues of ricin A chain were analyzed by site-directed mutagenesis and X-ray diffraction to help assess their roles in the mechanism of action of this toxic N-glycosidase enzyme. Arg180 is thought, from X-ray studies, to protonate the adenine substrate at N3; this facilitates bond cleavage and is crucial to the mechanisms of action. The residue was converted to Gln and initial rate data measured. Km for the mutant is not significantly affected, increasing only 2-fold. The kcat, however, is decreased approximately 1000-fold. This is consistent with a simple interpretation that Arg180 is involved more in transition state stabilization than in substrate binding. Tyrosines 80 and 123 are known from X-ray models to stack on either side of the substrate adenine ring. When they were each converted to serine overall activity was reduced 160- and 70-fold respectively against ribosomes from Artemia salina. These effects are each approximately 10 times greater than when the residues were previously converted to phenylalanines. Sufficient protein for the Tyr80 to Phe mutant was obtained to carry out an X-ray analysis. Together with mutagenesis data, the structure suggests that the invariance of the two active site Tyr residues is largely caused by structural stability.

Binding Sites↗
PubMed1992

Inhibition of Sucrose Enhancer Effect of the Potato Proteinase Inhibitor II Promoter by Salicylic Acid.

Effect of salicylic acid (SA) on the expression of the potato proteinase inhibitor (PI) II promoter was studied with transgenic tobacco plants (Nicotiana tabacum) carrying a gene fusion between the PI-II promoter and the chloramphenicol acetyltransferase (cat) reporter. As previously observed, the PI-II promoter was inducible by wounding and the promoter activity was further enhanced by sucrose. Addition of SA did not influence the wound induction of the PI-II promoter but significantly inhibited the sucrose response. The 5'-deletion mutant -573 was unable to respond to wounding but did respond to sucrose and SA. The 3'-deletion analysis indicated the presence of a sucrose-responsive element between -574 and -520. A study of the insertion mutants revealed the function of another sucrose-responsive element between -522 and -500. Enhancer effects of these sucrose-responsive elements were inhibited by SA. These studies suggest that SA inhibits PI-II promoter activity by decreasing the sucrose response. Analysis of SA-related chemicals revealed that only acetyl-SA showed a similar inhibitory effect, and other hydroxybenzoic acids had little or no effect on the sucrose enhancer activity. Therefore, it seems that the interaction between SA and the receptor molecule is specific.

Journal Article↗
PubMed1992

Regional localization of the intestinal mucin gene MUC3 to chromosome 7q22.

The gene MUC3 which codes for a mucin expressed in intestine (Gum et al. 1990) has previously been mapped, using somatic cell hybrids, to chromosome 7. We describe here the regional localization of MUC3 to chromosome 7q22 by in situ hybridization. Preliminary linkage analysis using CEPH (Centre d'Etude du Polymorphisme Humain) families supports this assignment and places MUC3 in the same linkage group as COL1A2 and CFTR.

Amino Acid Sequence↗
PubMed1992

Minimum scan speeds for suppression of motion artifacts in CT.

Cardiac and ventilatory motions cause artifacts at chest computed tomography (CT). To determine how short the scan times on third-generation units must be to avoid such artifacts, motion was measured with fast and ultrafast CT scans. Minimum detectable motion was then determined. The longest scan time that avoided a barely perceptible artifact was calculated by dividing the minimum detectable motion by the peak physiologic velocity. The posterior left ventricular wall moved at a maximum velocity of 52.5 mm/sec, necessitating a scan time of 19.1 msec or less to avoid artifact. Lung vessels near the heart moved at 40.5 mm/sec for a scan time of 24.7 msec or less. During quiet breathing, pulmonary vessels moved at 10.7 mm/sec for a scan time of 93.5 msec or less. The authors conclude that the shortest scan time on third-generation units (0.6 second) cannot prevent all artifacts arising from motion in the chest. Even ultrafast scan times (50 msec) are not short enough to eliminate artifacts on these units. Thus, reduction of motion artifacts will require techniques other than fast scanning.

Artifacts↗
PubMed1992

Nucleotide sequence and exon-intron structure of the bovine transition protein 1 gene.

The nucleotide sequence and exon-intron structure of the bovine transition protein 1 gene was determined. It consists of 2 exons (E1, 139 bp; E2, 29 bp) and a single intron (220 bp). The position of the transcription initiation site was determined 30 nucleotides upstream of ATG. TAAATA- and CAAT-boxes were found 60 and 121 bp upstream of the ATG-translation start point, respectively. It was observed that transition protein 1 is highly conserved in mammals at the nucleotide as well as at the amino acid level.

Amino Acid Sequence↗
PubMed1992

[Conceptual vs. indexical symptomatologies of schizophrenia].

We discussed the difference of conceptual and indexical symptomatologies of schizophrenia through critics upon the theory of Eugen Bleuler, the diagnostic schema of Kurt Schneider and several recent theories of negative symptoms of schizophrenia. The notion of the group of schizophrenia of Bleuler, which is a descriptive expression of the phenomenon originally grasped in the inter-human relationships, is of conceptual value but confusing when used indexically for the definition of the illness. In the diagnostic concept of Schizophrenia by Schneider, although he explicitly sought for indexical value without any conceptual prejudice, Jaspers' notion of the psychoses defined by understandability is implicitly included. Schizophrenia is regarded as a form of psychosis which is, following Jaspers, a synonym of madness. Since then, the value of Schneider's 1st rank symptoms has been generally acknowledged and they have contributed to the development of operational diagnostic criteria of schizophrenia. However, the general neglect of unproductive symptoms has caused a new stream of operational symptomatology, namely negative symptoms. This stream includes not only biological researches but also ideological investigations of the essential disturbance of schizophrenia, which have been totally ignored in the operational symptomatology. The discussion of negative symptoms of schizophrenia is complexed because it contains both indexical and conceptual symptomatologies: this very complexity also contains the possibility of the integration of these two apparently distant methods.

Humans↗
PubMed1992

Smooth muscle myosin isoform distribution and myosin ATPase in hypertrophied urinary bladder.

Hypertrophy of the urinary bladder was produced in rabbit by partial ligation of the urethra. Electrophoresis of the bladder smooth muscle myosin on highly porous (3.5-7% gradient) SDS-polyacrylamide gel revealed two heavy chain isoforms, SM-1 and SM-2 with approximate molecular weights of 204,000 and 200,000, respectively. The ratio of the SM-2 to SM-1 heavy chain is 3:1 for myosin isolated from normal bladder smooth muscle, and this ratio changes to about 1:1 in hypertrophied bladder. Despite a change in the ratio of SM-2 to SM-1, the myosin ATPase and the actin-activated ATPase activities are not altered in response to hypertrophy.

Animals↗
PubMed1992

Explantation of mesangial cell 'hillocks': a method for obtaining human mesangial cells in culture.

A simple method is presented for selective cell culture of human mesangial cells using explantation of mesangial cell hillocks. Glomeruli which had been incubated with collagenase were explanted on plastic tissue culture flasks. Three to 6 weeks after explantation, a rapidly growing multilayer of elongated mesangial cells was observed to grow over the previously established monolayer of glomerular epithelial cells, ultimately forming multiple nodular foci of mesangial cells or 'mesangial cell hillocks'. By explanting mesangial cell hillocks selectively, pure mesangial cell cultures were easily obtained. When compared with mesangial cells grown in mixed cultures from glomerular explants, the hillock-derived cells were identical in morphology, growth characteristics, cell markers and synthesis of extracellular matrix. This system provides a simple method for the isolation of human mesangial cells in culture.

Adolescent↗
PubMed1992

Giant negative T waves after maxillofacial surgery.

A patient developed strongly negative T waves following anesthesia for maxillofacial surgery. The electrocardiogram was normal preoperatively, except for a single premature ventricular depolarization, and no abnormalities were noted during the operation. Postoperatively, the T wave gradually inverted in almost all leads and approached the criterion of -10 mm for giant negative T waves in V3 2 days postoperatively. The T wave returned to normal approximately 4 months later. Although the T-wave inversion in this patient may have been caused by surgical trauma to the sympathetic nerve supply to the heart or by myocardial infarction, the exact cause remains undetermined.

Anesthesia, Dental↗
PubMed1991

Denaturation and renaturation of myeloperoxidase. Consequences for the nature of the prosthetic group.

The effects of the chaotropic agent, guanidine HCl, on the chlorinating activity, optical absorption, EPR, and resonance Raman spectra of myeloperoxidase have been studied. In the presence of the agent the Soret optical absorption of the reduced enzyme (lambda max = 474 nm) is blue shifted to 448 nm, a position similar to heme alpha-containing enzymes. The chlorinating activity of the enzyme disappears, and EPR spectra show a loss of intensity of the rhombic high spin heme signals (gx = 6.9; gy = 5.4) and the appearance of a more axial high spin signal (gx = gy = 6.0). Surprisingly the effects of guanidine HCl are partly reversible. Upon decreasing the concentration of the chaotropic agents by dilution, both the chlorinating activity and the original optical spectrum of native reduced enzyme (lambda max = 474 nm) are partly restored. The resonance Raman spectra of denatured cyanomyeloperoxidase are less complicated than those of native myeloperoxidase, which have been interpreted previously to suggest an iron chlorin chromophore. The multiple lines in the oxidation state marker region are not seen in the spectra of the denatured species. The changes suggest that upon denaturation the macrocycle is converted into a more symmetric structure. Since the effects on the optical absorption spectrum are reversible we speculate that, in the native enzyme, an apparent porphyrin macrocycle undergoes a reversible interaction with amino acid residues in the protein which creates an asymmetry in the electronic distribution of the macrocycle. Comparison of the Raman spectra of denatured cyanomyeloperoxidase with those of analogous heme alpha model complexes suggests the presence of a formyl group in the denatured species; our data, however, demonstrate that the chromophore structure is not identical to heme alpha and may contain a different C beta substitution on the ring macrocycle.

Chlorine↗