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Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 595 records · Page 33Linked to original sources
PubMed1995

The size heterogeneity of human lysyl oxidase mRNA is due to alternate polyadenylation site and not alternate exon usage.

We have isolated the entire gene coding for human lysyl oxidase. Coding and untranslated domains of human lysyl oxidase mRNA were found in 7 exons, distributed throughout approximately 14 kb of human genomic DNA. The appearance of exon sequences in lysyl oxidase mRNA in several human tissues was determined using a reverse transcriptase - PCR assay. In contrast to a previous report, this analysis has unambiguously shown that the size heterogeneity of lysyl oxidase mRNA was not due to alternate usage of any of the exons of the lysyl oxidase gene. Moreover, DNA sequence analysis of the entire 3.8 kb 3'-untranslated region (UTR) within exon 7 revealed multiple poly-adenylation sites which were shown to be differentially expressed in human skin fibroblasts. This differential usage of polyadenylation sites within the 3'-UTR explains the appearance of multiple lysyl oxidase mRNAs of different sizes.

Adenosine Monophosphate↗
PubMed1995

Quality control of cathode-ray tube monitors for medical imaging using a simple photometer.

As computer monitors are used more in medical imaging and the use of picture archiving and communication system workstations with multiple monitors is increasing, quality control protocols become necessary to track subtle variations in performance characteristics. Several tests based on previously published work were applied to 10 monitors of three different types over a period of 5 months. Each test is explained, and the results are shown. For example, without corrective adjustments, 2 monitors from the same workstation showed a small but steady decline in maximum luminance of 8.1% and 7.6% over the course of 11 weeks that was not perceptible. From this experience, we took the first step toward developing a practical and useful quality control protocol. The proposed protocol requires only a photometer and the ability to generate the Society of Motion Picture and Television Engineers (SMPTE) test pattern, and takes approximately 5 minutes per monitor per week to gather data.

Data Display↗
PubMed1995

Evaluation of the medical diagnostic imaging support system based on 2 years of clinical experience.

The Medical Diagnostic Imaging Support (MDIS) system at Madigan Army Medical Center (MAMC) has been operational in a phased approach since March 1992. Since then, nearly all image acquisition has been digital with progressively increasing primary softcopy diagnosis used. More than 375,000 computed radiography (CR) images as well as other modality images have been archived. Considerable experience in installation and implementation phasing has been gained. The location and ergonomic aspects of equipment placement were refined with time. The original clinical scenario was insufficiently detailed and additions were made to facilitate smoother and more complete transition toward a filmless environment. The MDIS system effectiveness and performance have been good in terms of operational workload throughout, background operations, and reliability. The important areas regarding reliability are image acquisition, output, display, database operations, storage, and the local area network. Fail-safe strategies have been continually improved to maintain continuous clinical image availability during the times when the MDIS system or components malfunction. Many invaluable lessons have been learned for effective quality assurance in a hospital-wide picture archiving and communication system. These issues include training, operational quality control, practical aspects of CR image quality, and increased timeliness in the generation and distribution of radiographic reports. Clinical acceptability has been a continuous process as each phase has been implemented. Clinical physicians quickly used the workstations soon after the start of MDIS at MAMC. The major advantage for clinicians has been the amount of time saved when retrieving multimodality images for review. On the other hand, the radiologists have been slower in their acceptance of the workstation for routine use.(ABSTRACT TRUNCATED AT 250 WORDS)

Computers↗
PubMed1995

Early glomerular changes in rats with dietary-induced hypercholesterolemia.

Increasing evidence suggests that lipids may be important modulators of progressive glomerular injury. We previously reported the long-term glomerular changes in rats with dietary-induced hypercholesterolemia. In this work, we evaluated the early glomerular changes induced by hypercholesterolemia that precede the development of glomerulosclerosis. In cholesterol-fed rats, an early macrophage influx was observed. This was associated with an increase in glomerular size, mesangial matrix expansion, lipid deposits, and foam cell formation. Immunohistochemical techniques showed that type IV collagen, fibronectin, and laminin were increased in cholesterol-fed rats. The mRNA expression for the alpha 1 chain of type IV collagen and an inhibitor of type IV collagenase were increased, suggesting that both increased synthesis and reduced degradation may be involved in cholesterol-induced mesangial matrix accumulation. The glomerular mRNA expression of transforming growth factor-beta 1 was also upregulated, suggesting that transforming growth factor-beta 1 could be an important mediator for mesangial matrix accumulation in hypercholesterolemic states. The early cholesterol-induced changes in the glomerulus are reminiscent in many respects to the process leading to glomerulosclerosis in the vessel wall.

Animals↗
PubMed1995

Neurologic characteristics of childhood lupus erythematosus.

Records of 108 patients with lupus erythematosus beginning in childhood (1953-1990) were reviewed; 25 had recorded neurologic findings. This is the largest group of childhood lupus erythematosus patients with neurologic disease that has been reported. The average age of children at the time of diagnosis of lupus was 154 months. There were 22 girls and 3 boys in the group. All patients met at least four of the 1982 American Rheumatism Association criteria for the classification of systemic lupus erythematosus. Average age at onset of neurologic difficulties was 168 months. In 4 patients, the neurologic symptoms preceded the diagnosis: 1 month (spastic diplegia), 1 month (bilateral weakness and spasticity), 24 months (chorea), and 26 months (chorea), respectively. Four patients had neurologic symptoms coincident with the diagnosis of lupus erythematosus. In those patients whose symptoms followed the diagnosis of lupus erythematosus, the average elapsed time until symptoms appeared was 33 months; the single lowest and highest outliers were discounted. Most frequent findings were headache (16/25) and behavioral aberrations (10/25). All behavioral manifestations were depression except in 1 patient. Other prevalent findings included hemichorea or chorea (7/25), cerebrovascular accident with hemiplegia or diplegia (7/25), seizures (5/25), visual loss (3/25), and cranial neuropathy (2/25). Vertigo and myelopathy occurred in 1 patient each. All patients were treated primarily with corticosteroids and azathioprine; in the presence of active disease, the drug dosages were increased with significant improvement in neurologic symptoms. Resolution usually occurred from days to months; most improved in a few days to a few weeks; 3-4 months was the longest period until symptoms subsided.

Adolescent↗
PubMed1995

Increased rate of hysterectomy in women undergoing surgery for osteoarthritis of the knee.

We performed a case-controlled study to determine whether previous gynecological surgery is associated with severe osteoarthritis (OA) of the knee, the hip or the spine, as well as mild OA of the knee. Patients who underwent surgical treatment for OA were defined as having severe OA. Patients with knee pain and radiographic grade 2 OA in a tibiofemoral joint on the Kellgren and Lawrence scale were defined as having mild knee OA. An increased rate of hysterectomy was observed in the severe knee OA group after adjustment for age and number of children, or even after adjustment for body mass index. Hysterectomy in this group was most often performed for myoma uteri. Patients with mild knee OA tended to have previous hysterectomy. From the results, we speculate that certain subsets of OA which often take a progressive course might be related to hysterectomy.

Adult↗
PubMed1995

Precipitation of insulinotropin in the presence of protamine: effect of phenol and zinc on the isophane ratio and the insulinotropin concentration in the supernatant.

PURPOSE: The purpose of this study is to determine the minimum quantity of protamine required for the completion of insulinotropin precipitation under different precipitation conditions. METHODS: The experiments involved combining insulinotropin with varying concentrations of protamine in pH 7.2 phosphate buffered saline and analyzing the concentrations of both proteins in the supernatant. Isophane ratio (the protamine/insulinotropin molar ratio that results in a minimum total protein concentration in the supernatant) was determined for different precipitation conditions. RESULTS: When neutral solutions of insulinotropin (pI 5.3) and protamine (pI 13.8) were combined, precipitation did not occur. However, in the presence of phenol and/or zinc, insulinotropin co-precipitated with protamine. In the presence of phenol, the isophane ratio and the insulinotropin concentration in the supernatant were determined to be 0.08 and 0.18 mg/ml, respectively. In the presence of zinc, the isophane ratio increased with zinc concentration, apparently from the precipitation of protamine in the presence of zinc. The isophane ratio and the insulinotropin concentration in the supernatant were 0.13 and 0.13 mg/ml, respectively, when the zinc/insulinotropin molar ratio was one. In the presence of phenol and zinc with the zinc/insulinotropin molar ratio of 1.0, the isophane ratio and the insulinotropin concentration in the supernatant were 0.11 and 1 microgram/ml, respectively. CONCLUSIONS: A method to determine the isophane ratio of protamine/insulinotropin precipitation was developed to determine the minimum quantity of protamine required for the completion of insulinotropin precipitation under different precipitation conditions. A synergistic effect between phenol and zinc on the precipitation of insulinotropin in the presence of protamine was found.

Animals↗
PubMed1995

The application of crystal soaking technique to study the effect of zinc and cresol on insulinotropin crystals grown from a saline solution.

PURPOSE: The purpose of this study is to investigate the effect of zinc and cresol on the structure of insulinotropin crystals. METHODS: Insulinotropin crystals grown from a saline solution were treated with zinc and/or m-cresol using a crystal soaking technique. The effects of these additives on the crystal structure were investigated with powder X-ray diffraction, photomicrography, and differential scanning calorimetry. The molecular interaction between insulinotropin and m-trifluorocresol in solution was also studied by 19F NMR: RESULTS: The data suggest that the original crystals grown from a saline solution have relatively weak lattice forces. After the addition of m-cresol to the suspension of the insulinotropin crystals, the crystals were immediately rendered amorphous. The m-cresol molecules which diffused into the crystals through solvent channels may have disturbed the lattice interactions that maintain the integrity of the crystal. In contrast, the zinc added to the suspension stabilized the crystal lattice so that the subsequent addition of m-cresol did not alter the integrity of the crystals. A marked increase in melting point (206 degrees versus 184 degrees) and heat of fusion (24.6 J/g versus 1.4 J/g) of the crystals was observed after the treatment with zinc. The solubility of the zinc treated crystals in a pH 7.1 phosphate buffered saline was 1/20 of that of the original crystals. CONCLUSION: When the insulinotropin crystals were treated with the additives using a crystal soaking method, the crystals underwent structural changes. Zinc stabilized the crystal lattice, and reduced the solubility of the peptide.

Amino Acid Sequence↗
PubMed1995

Human mesangial cell production of monocyte chemoattractant protein-1: modulation by lovastatin.

Macrophages play a critical role in the progression of clinical and experimental glomerular injury. Serum-stimulated human fetal mesangial cells in culture produce a chemotactic factor that is monocyte-selective. This chemotactic factor is most likely monocyte chemoattractant protein-1 (MCP-1) as a monoclonal antibody directed against MCP-1, but not an irrelevant antibody, suppressed the mesangial cell-derived chemotactic activity. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase by lovastatin resulted in a reduction of the mesangial cell-derived chemotactic activity as well as MCP-1 mRNA expression. The inhibitory effects of lovastatin in the presence of exogenous cholesterol were reversed by mevalonate, suggesting a role for isoprenoid intermediates of the mevalonate pathway and/or isoprenylated proteins in mesangial cell MCP-1 regulation. These findings suggest an additional mechanism by which HMG-CoA reductase inhibition in vivo may reduce glomerular injury.

Cells, Cultured↗
PubMed1995

Inhibitory effects of Oriental herbal medicines on IL-8 induction in lipopolysaccharide-activated rat macrophages.

Cytokine-induced neutrophil chemoattractant (CINC), a rat interleukin-8 (IL-8), was quantitated by using a sensitive ELISA. The CINC was induced up to 20 ng/ml from basal 1-2 ng/ml in lipopolysaccharide (LPS)-activated peritoneal macrophages. This CINC induction was significantly inhibited by steroidal anti-inflammatory drugs including dexamethasone, but not by non-steroidal drugs including indomethacin at all. Nine out of 59 herbal medicines which are frequently used in Korean traditional prescriptions for inflammatory diseases exhibited more than 50% of inhibition on the CINC induction by their total methanol extracts with 0.1 mg/ml as a final concentration. The active 9 total extracts were prepared from radix of Aralia continentalis, rhizoma of Cnidium officinale, rhizoma of Coptis chinensis, tuber of Fritillaria verticillata, radix of Saussurea lappa, tuber of Sparganium stoloniferum, flower of Syzygium aromaticum, semen of Trichosanthes kirilowii, and herba of Tripterygium regelii. These total extracts were sequentially fractionated with dichloromethane, ethyl acetate, butanol, and water. Among the solvent-fractionated extracts with 0.05 mg/ml as a final concentration, more than 50% of inhibition on the CINC induction was exhibited by the dichloromethane fraction of Aralia continentalis; the water fraction of Fritillaria verticillata; the dichloromethane fraction of Saussurea lappa; the dichloromethane, ethyl acetate, and butanol fractions of Syzygium aromaticum; the dichloromethane, ethyl acetate, and water fractions of Trichosanthes kirilowii; and the dichloromethane and ethyl acetate fractions of Tripterygium regelii.

Animals↗
PubMed1995

Effect of a recombinant N-terminal fragment of bactericidal/permeability-increasing protein (rBPI23) on cerebrospinal fluid inflammation induced by endotoxin.

Endotoxin triggers the subarachnoid inflammation of gram-negative meningitis. This study examined the ability of a recombinant N-terminal fragment of bactericidal/permeability-increasing protein (rBPI23) to block endotoxin-induced meningitis in rabbits. Intracisternal (ic) injection of 10-20 ng of meningococcal endotoxin induced high cerebrospinal fluid (CSF) concentrations of tumor necrosis factor (TNF) and CSF pleocytosis and increased CSF lactate concentrations. ic administration of rBPI23 significantly reduced meningococcal endotoxin-induced TNF release into CSF (P < .005), lactate concentrations (P < .001), and CSF white blood cell counts (P < .01). No such effect was observed in animals receiving intravenous rBPI23. Concentrations of rBPI23 in CSF were high after ic administration but low or undetectable after systemic administration. Thus, high concentrations of rBPI23 can effectively neutralize meningococcal endotoxin in CSF, but low CSF concentrations after systemic administration currently limit its potential usefulness as adjunctive drug treatment in gram-negative meningitis.

Animals↗
PubMed1995

Age structure and reproductive composition of summer Musca autumnalis (Diptera: Muscidae) populations estimated by pterin concentrations.

Pterins in face flies, Musca autumnalis DeGeer, were measured spectrofluorimetrically to estimate the chronological ages of adults in natural summer populations. The age distributions showed a systematic undersampling of young males. Exponential, Gompertz, and Weibull models were fitted to the age distributions. A 1-parameter exponential model suggested mean daily survival rates of 0.83 for female face flies, and a mean life expectation of 5.5 d. But the Weibull model best fit the age distributions, providing mean life expectations of 10.1 and 11 d for males and females, respectively. Ovarian dynamics were examined with respect to chronological age and delays were detected in vitellogenesis and oviposition. Face fly populations seemed to reproduce at less than the maximum rate allowed by prevailing temperatures, at which it was estimated that an average female would undergo 2.2 ovarian cycles and have a lifetime fecundity of 28.5 female progeny.

Aging↗
PubMed1995

Computational studies of transthoracic and transvenous defibrillation in a detailed 3-D human thorax model.

A method for constructing and solving detailed patient-specific 3-D finite element models of the human thorax is presented for use in defibrillation studies. The method utilizes the patient's own X-ray CT scan and a simplified meshing scheme to quickly and efficiently generate a model typically composed of approximately 400,000 elements. A parameter sensitivity study on one human thorax model to examine the effects of variation in assigned tissue resistivity values, level of anatomical detail included in the model, and number of CT slices used to produce the model is presented. Of the seven tissue types examined, the average left ventricular (LV) myocardial voltage gradient was most sensitive to the values of myocardial and blood resistivity. Incorrectly simplifying the model, for example modeling the heart as a homogeneous structure by ignoring the blood in the chambers, caused the average LV myocardial voltage gradient to increase by 12%. The sensitivity of the model to variations in electrode size and position was also examined. Small changes (< 2.0 cm) in electrode position caused average LV myocardial voltage gradient values to increase by up to 12%. We conclude that patient-specific 3-D finite element modeling of human thoracic electric fields is feasible and may reduce the empiric approach to insertion of implantable defibrillators and improve transthoracic defibrillation techniques.

Computer Simulation↗
PubMed1995

Predicting cardiothoracic voltages during high energy shocks: methodology and comparison of experimental to finite element model data.

Finite element modeling has been used as a method to investigate the voltage distribution within the thorax during high energy shocks. However, there have been few quantitative methods developed to assess how well the calculations derived from the models correspond to measured voltages. In this paper, we present a methodology for recording thoracic voltages and the results of comparisons of these voltages to those predicted by finite element models. We constructed detailed 3-D subject-specific thorax models of six pigs based on their individual CT images. The models were correlated with the results of experiments conducted on the animals to measure the voltage distribution in the thorax at 52 locations during synchronized high energy shocks. One transthoracic and two transvenous electrode configurations were used in the study. The measured voltage values were compared to the model predictions resulting in a correlation coefficient of 0.927 +/- 0.036 (average +/- standard deviation) and a relative rms error of 22.13 +/- 5.99%. The model predictions of voltage gradient within the myocardium were also examined revealing differences in the percent of the myocardium above a threshold value for various electrode configurations and variability between individual animals. This variability reinforces the potential benefit of patient-specific modeling.

Animals↗
PubMed1995

A carbon starvation survival gene of Pseudomonas putida is regulated by sigma 54.

By using mini-Tn5 transposon mutagenesis, two mutants of Pseudomonas putida ATCC 12633 were isolated which showed a marked increase in their sensitivity to carbon starvation; these mutants are presumably affected in the Pex type of proteins that P. putida induces upon carbon starvation (M. Givskov, L. Eberl, and S. Molin, J. Bacteriol. 176:4816-4824, 1994). The affected genes in our mutants were induced about threefold upon carbon starvation. The promoter region of the starvation gene in the mutant MK107 possessed a strong sigma 54-type-promoter sequence, and deletion analysis suggested that this was the major promoter regulating expression; this was confirmed by transcript mapping in rpoN+ and rpoN mutant backgrounds. The deletion analysis implicated a sequence upstream of the sigma 54 promoter, as well as a region downstream of the transcription start site, in the functioning of the promoter. Two sigma 70-type Pribnow boxes were also detected in the promoter region, but their transcriptional activity in the wild type was very weak. However, in a sigma 54-deficient background, these promoters became stronger. The mechanism and possible physiological role of this phenomenon and the possibility that the sequence upstream of the sigma 54 promoter may have a role in carbon sensing are discussed.

Base Sequence↗