Pulmonary dysfunction in advanced liver disease.
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Adult↗
Biomedical subjects
S Kim
Publications and source records attributed to S Kim.
Amyotrophic lateral sclerosis (ALS): a phylogenetic disease of the corticomotoneuron?
It is proposed that the primary cell involved in amyotrophic lateral sclerosis (ALS) is the corticomotoneuron. The spinal motoneuron becomes affected as a result of antegrade effects. This hypothesis does not negate most of the presently popular theories regarding the pathogenesis of ALS, but directs focus to one cell type--the corticomotoneuron. It takes cognizance of the complex, monosynaptic, corticomotoneuronal-spinomotoneuronal connections that have evolved in primates, and especially in man. It might explain the lack of any natural or thus far induced animal model which closely mimics the human disease. Threshold measurements to transcotical magnetic stimulation might be used to test the hypothesis. Replication of ALS in an animal is only likely to succeed in a nonhuman primate.
Amyotrophic Lateral Sclerosis↗
A specific brain tract guides follower growth cones in two regions of the zebrafish brain.
Neurons of the nucleus of the posterior commissure (nuc PC), an identifiable cluster of neurons in the embryonic zebrafish brain, project growth cones ventrally along the posterior commissure to the anterior tegmentum where the PC intersects two longitudinal tracts, the tract of the postoptic commissure (TPOC) and the medial longitudinal fasciculus (MLF). Once at the intersection, nuc PC growth cones turn posteriorly onto the TPOC in the dorsal tegmentum and follow it to the hindbrain. Previously we showed that in the absence of the TPOC, nuc PC growth cones often extended along aberrant pathways suggesting that fasciculation, that is, contact with TPOC axons is an important factor in guiding growth cones along their normal pathway. However, a significant number of nuc PC growth cones also followed their normal pathway suggesting that cues associated with the dorsolateral tegmentum, independent of the TPOC, can also guide nuc PC growth cones. We have now confirmed using electron microscopy that nuc PC growth cones fasciculate with axons in the TPOC. In the absence of the TPOC, the nuc PC growth cones that extend along their normal pathway do so in contact with dorsolateral neuroepithelial cells. This suggests that cues associated with these cells can also guide the nuc PC growth cones. Furthermore, in the absence of the TPOC axons, these growth cones now inappropriately turn onto axons that normally intersect the TPOC near the border of the midbrain and hindbrain, that is, at a second intersection of tracts. This suggests that fasciculation with TPOC axons may also guide nuc PC growth cones in this second region of the brain.
Animals↗
Molecular details of tomato extensin and glycine-rich protein gene expression.
In a recent publication (Plant Molecular Biology 16: 547-565 (1991)), Showalter et al. described the isolation and initial characterization of fifteen extensin and extensin-like tomato cDNAs. These cDNAs were determined to fall into five distinct classes; class I and II clones encoded extensins, class III and V clones encoded glycine-rich proteins (GRPs), and class IV clones encoded a portion of a GRP sequence on one DNA strand and a portion of an extensin sequence on the other DNA strand. In this publication, a more detailed analysis of the expression of these cDNA classes was performed with respect to wounding in various tomato organs, development, kinetics and systemic extent of the wound response, ethylene treatment, abscisic acid (ABA) treatment, and drought stress by using RNA gel blot hybridizations. In general, extensin gene expression was readily detected in stems and roots, but not in leaves. With both class I and II extensin cDNA probes, wound-induced accumulation of mRNA in stems was first detected between 4 and 8 h after wounding with maximal accumulation occurring after 12 h. Moreover, these extensin wound responses were detected locally at the wound site but not systemically. Expression of the class III GRP was largely limited to wounded stem tissue. Initial detection and maximal accumulation of the class III GRP mRNA was similar to the extensins mRNAs; however, this GRP wound response occurred both locally and systemically. Additionally, abscisic acid treatment and drought stress resulted in the marked accumulation of the class III GRP mRNA in tomato stems, but did not alter the expression of the other cDNA classes. In contrast, expression of the class V GRP occurred in stems and roots and to a lesser extent in leaves and decreased in response to wounding over a 24 h time period. The class V GRP wound response was further characterized by an early, transient accumulation of mRNA occurring 2-4 h after wounding in stems and by its local nature.
Blotting, Northern↗
In vivo and in vitro methylation of lysine residues of Euglena gracilis histone H1.
We have earlier identified and purified two protein-lysine N-methyltransferases (Protein methylase III) from Euglena gracilis [J. Biol. Chem., 260, 7114 (1985)]. The enzymes were highly specific toward histone H1 (lysine-rich), and the enzymatic products were identified as epsilon-N-mono-, di- and trimethyllysines. These earlier studies, however, were carried out with rat liver histone H1 as the in vitro substrate. Presently, histone H1 has been purified from Euglena gracilis through Bio-Rex 70 and Bio-Gel P-100 column chromatography. The Euglena histone H1 showed a single band on SDS-polyacrylamide gel electrophoresis and behaved like other histone H1 of higher animals, whereas it had a much higher Rf value than the other histones H1 in acid/urea gel electrophoresis. When the Euglena histone H1 was [methyl-3H]-labeled in vitro by a homologous enzyme (one of the two Euglena protein methylase III) and analyzed on two-dimensional gel electrophoresis, three distinctive subtypes of histone H1 were shown to be radiolabeled, whereas five subtypes of rat liver histone H1 were found to be labeled. Finally, by the combined use of a strong cation exchange and reversed-phase Resolve C18 columns on HPLC, we demonstrated that Euglena histone H1 contains approximately 9 mol% of epsilon-N-methyllysines (1.40, 1.66, and 5.62 mol% for epsilon-N-mono-, di- and trimethyllysines, respectively). This is the first demonstration of the natural occurrence of epsilon-N-methyllysines in histone H1.
Animals↗
Biologic properties of eugenol and zinc oxide-eugenol. A clinically oriented review.
Eugenol-containing dental materials are frequently used in clinical dentistry. When zinc oxide-eugenol (ZOE) is applied to a dentinal cavity, small quantities of eugenol diffuse through the dentin to the pulp. Low concentrations of eugenol exert anti-inflammatory and local anesthetic effects on the dental pulp. Thus use of ZOE temporary filling may facilitate pulpal healing; on the other hand, high eugenol concentrations are cytotoxic. Direct application of eugenol to pulp tissue may result in extensive tissue damage. The ability of ZOE-based endodontic sealers to influence periapical tissue healing is considered in view of eugenol's anti-inflammatory and toxic properties.
Biocompatible Materials↗
Diabetic nephropathy: duplex Doppler ultrasound findings.
To evaluate the correlations among Doppler sonographic findings, morphologic sonographic findings, and laboratory findings representing renal functional status, duplex Doppler sonography of the kidney was performed in 32 patients with diabetes mellitus. Resistive indices obtained in the region of the arcuate or the interlobar arteries in patients with elevated serum creatinine levels were significantly higher than those in patients with normal serum creatinine levels (P < 0.05). Also, there was a significant correlation between the resistive indices and creatinine clearance levels (correlation coefficient, -0.828). There was a significant difference between the serum creatinine levels of patients with normal renal cortical echogenicity and those with increased cortical echogenicity (P < 0.05). Analysis of the Doppler spectrum of the intrarenal arteries in conjunction with careful evaluation of the renal cortical echogenicity may be helpful in sonographic prediction of the renal functional status in patients with diabetes mellitus.
Albuminuria↗
HLA-DR expression in human fetal thymocytes.
We analyzed the expression of MHC class I (W6/32) and class II (HLA-DR) antigens on human fetal and postnatal thymocytes by fluorescence-activated cell sorting. Less than 5% of prenatal thymocytes expressed HLA-DR before week 12 of gestation. However, the number of HLA-DR-positive cells significantly increased during the late second and third trimester of gestation, when greater than 50% of prenatal thymocytes expressed HLA-DR. Such high-level expressions of HLA-DR in fetal thymocytes were also demonstrated by Northern-blot analysis and immunohistochemistry. After birth, the percentage of HLA-DR-positive cells in thymocytes decreased gradually. A high-level expression of class I antigen was also observed in thymocytes from the early stages of gestation, but, in contrast to MHC class II, a majority of postnatal thymocytes maintained high levels of class I antigen after birth.
Cell Separation↗
Photorealistic image generation of molecular structure on PC screen using the ray-tracing technique.
A PC version of three-dimensional molecular graphics package has been developed to run under MS-DOS environment on IBM PC-compatible computers equipped with a VGA graphics board. The program consists of two parts: a menu-driven interactive system module in EGA mode, and a ray-tracing module in VGA mode. In the 256-color VGA mode, ray-tracing images are represented with a 4-color map, with 64 levels for each color: 32 levels of illuminance and 32 levels of saturation. Molecular structure can be analyzed along various directions with various light sources. Ray-tracing images are also represented in a 16-color EGA mode with the half-toning method, which can display 76 gray levels for each color. To obtain good photo-realistic images in an efficient way, we have used two light sources, with an intensity ratio of 7:3, which are located in front of the top right and bottom left corners of the screen.
Carboxypeptidases↗
Effects of CO2 laser energy on dentin permeability.
The effect of a CO2 laser on the structure and permeability of smear layer-covered human dentin was evaluated in vitro. Three different energy levels were used (11, 113, and 566 J/cm2). The lowest exposure to the laser energy increased dentin permeability, measured as a hydraulic conductance, due to partial measured as a hydraulic conductance, due to partial loss of the superficial smear layer and smear plugs. The intermediate energy level also increased dentin permeability by crater formation, making the dentin thinner. The lack of uniform glazing of the surface of the crater, leaving its surface porous and in communication with the underlying dentinal tubules also contributed to the increase in dentin permeability seen with the intermediate laser energy. The highest laser energy produced complete glazing of the crater surfaces and sealed the dentinal tubules beneath the crater. However, it also completely removed the smear layer in a halo zone about 100-microns wide around each crater which increased the permeability of the pericrater dentin at the same time it decreased the permeability of the dentin within the crater. The combined use of scanning electron microscopy and permeability measurements provides important complementary information that is essential in evaluating the effects of lasers on dentin.
Adolescent↗
Magnetic resonance imaging of human teeth.
There is a need in clinical dentistry for improved diagnostic methods for an accurate evaluation of pulp tissue pathosis. The purpose of this investigation was to attempt to image extracted human teeth with the aim of establishing the possible future application of magnetic resonance imaging in the diagnosis of pulpal pathosis. The results of this pilot study demonstrate that, in the in vitro setting, the outline of the tooth and pulp chamber can be imaged with a high degree of accuracy, and detailed images of the periodontal membrane and gross pulpal anatomy can be obtained. There were obvious differences in the signals given off by different locations within these teeth, and the images of the dental pulp tissue were detailed enough to suggest the possible correlation with histology. The high (9.4 T) field strengths used in this study demonstrate the in vitro application of this technology and the future possibilities for diagnosis of periodontal and odontogenic problems are significant.
Dental Pulp Diseases↗
Activation of human immunodeficiency virus by herpes simplex virus.
Heterologous viruses have been examined for their ability to accelerate the course of infection with the human immunodeficiency virus (HIV) type 1. In this study, ACH-2 cells persistently infected with HIV-1 exhibited augmented HIV-1 replication as a result of superinfection with herpes simplex virus (HSV) type 1. Using HSV-1 mutants with deletions in the genes encoding immediate-early proteins ICP0, ICP4, and ICP27, it was found that ICP0 and ICP27, but not ICP4, were essential for up-regulation of HIV replication. Northern blot analysis showed that this activation of HIV was characterized by an initial rise in the level of the small, subgenomic (2.0 and 4.3 kb) mRNA species, followed by an increase in the level of unspliced genomic (9.2 kb) mRNA. Such a shift in transcriptional phase recapitulates the early-to-late transition seen in single-step growth curves of acute HIV-1 infection. Thus, HSV can activate HIV-1 from latency in ACH-2 cells, this activation of HIV is independent of productive HSV replication since the delta ICP4 deletion mutant is replication-incompetent, and this activation is evident as an increase in the steady-state levels of HIV transcripts.
CD4-Positive T-Lymphocytes↗
Inhibition of elevated hepatic glutathione abolishes copper deficiency cholesterolemia.
Dietary copper deficiency causes hypercholesterolemia and increased hepatic 3-hydroxy-3-methyl-glutaryl coenzyme A (MHG-CoA) reductase activity and increased hepatic glutathione (GSH) in rats. We hypothesized that inhibition of GSH production by L-buthionine sulfoximine (BSO), a specific GSH synthesis inhibitor, would abolish the cholesterolemia and increased HMG-CoA reductase activity of copper deficiency. In two experiments, two groups of 20 weanling male rats were fed diets providing 0.4 and 5.8 micrograms Cu/g, copper-deficient (Cu-D) and copper-adequate (Cu-A), respectively. At 35 days plasma cholesterol was significantly elevated by 30 to 43% in Cu-D and 10 animals in each of the Cu-D and Cu-A groups were randomly assigned to receive 10 mM BSO solution in place of drinking water and continued on the same diets for another 2 wk. At necropsy Cu-D animals had a significant 52 to 58% increase in plasma cholesterol. BSO administration abolished the cholesterolemia in Cu-D rats, but had no influence on plasma cholesterol of Cu-A rats. Hepatic GSH was increased 39 to 82% in Cu-D rats and BSO abolished this increase. BSO was without effect on cardiac hypertrophy, plasma and liver copper, and hematocrit indices of copper status. Liver microsome HMG-CoA reductase activity was significantly increased 85 to 288% in Cu-D rats and BSO administration abolished this increase in activity in Cu-D rats. The results suggest that copper deficiency cholesterolemia and elevated HMG-CoA reductase activity are a consequence of elevated hepatic GSH, and provide evidence for GSH regulation of cholesterol metabolism in intact animals.
Animals↗
Transactivation of human immunodeficiency virus type 1 long terminal repeat-directed gene expression by the human foamy virus bel1 protein requires a specific DNA sequence.
Human foamy virus (HFV) encodes the transcriptional transactivator bel1. The bel1 protein transactivates HFV long terminal repeat (LTR)-directed gene expression by recognizing a region in U3. It also transactivates human immunodeficiency virus type 1 (HIV-1) LTR-directed gene expression in transient transfection assays. To identify the specific region in HIV-1 LTR responsible for bel1 action, we examined the effect of bel1 on chloramphenicol acetyltransferase (CAT) gene expression in transfected cells with a series of mutant HIV-1 LTR/CAT plasmids. The region between -158 and -118 from the transcription initiation site, immediately upstream of the core enhancer element, was identified as responsible for the transactivation by bel1. In addition, bel1 transactivated a heterologous promoter when this region was positioned upstream of it in the sense and antisense orientations. Optimal transactivation of the HIV-1 LTR by bel1 did not require an intact TAR sequence, suggesting that the binding of tat to the TAR sequence is not a prerequisite for bel1 function in HIV-1 LTR-directed gene expression. In the region of the HIV-1 LTR that is necessary for the bel1-mediated transactivation, we have found a sequence which is conserved between HIV-1 and HFV. Our results suggest that the bel1 action on HIV-1 seems to be mediated by a specific DNA sequence which is shared by both the HIV-1 LTR and HFV LTR.
Base Sequence↗
Effects of prorenin on blood pressure and plasma renin concentrations in stroke-prone spontaneously hypertensive rats.
To examine the possible activation of prorenin in the circulation, recombinant rat prorenin was intravenously given to pentobarbital-anesthetized rats. Bolus injection of prorenin at the dose of 100 micrograms angiotensin I (ANG I).h-1.kg-1 into Wistar rats, leading to a 15-fold increase in plasma prorenin concentrations (from 27 +/- 6 to 393 +/- 75 ng ANG I.h-1.ml-1) at 5 min after the injection, did not affect blood pressure, heart rate, and plasma active renin concentrations throughout experiments. On the other hand, the administration of active renin at the dose of 1, 3, and 10 micrograms ANG I.h-1.kg-1 increased mean blood pressure of Wistar rats by 8 +/- 2, 15 +/- 2, and 27 +/- 4 mmHg, respectively. Similar results were obtained in Wistar rats at 18 h after bilateral nephrectomy. These results confirmed no activation of prorenin in the circulation of normotensive rats. The activation of prorenin was also examined on both stroke-prone spontaneously hypertensive rats (SHRSP) and 18 h-nephrectomized SHRSP. There was no rise in blood pressure or plasma active renin concentrations in both groups of SHRSP after injection of prorenin. Thus the elevated plasma active renin in SHRSP [Shibota, M., A. Nagaoka, A. Shino, and T. Fujita. Am. J. Physiol. 236 (Heart Circ. Physiol. 5): H409-H416, 1979] seems to be caused by the enhanced release of active renin from the kidney rather than the activation of circulating prorenin.
Animals↗
Immunocytochemical studies suggest two pathways for enteroendocrine cell differentiation in the colon.
Enteroendocrine cells represent the most heterogeneous population of terminally differentiated cells in the mouse intestinal epithelium. Each of the approximately 15 different enteroendocrine cell subpopulations shows characteristic distributions along both the cephalocaudal and crypt-to-villus (in the small intestine) or crypt-to-surface epithelial cuff (in the colon) axes of the gut. These cells provide a sensitive model for studying how the continuously renewing gut epithelium is able to establish and maintain its spatial differentiation. Enteroendocrine cells are derived from the same multipotent stem cell that gives rise to enterocytes and goblet and Paneth cells. Regional differences in enteroendocrine cell number and type reflect positional differences in the differentiation programs of this lineage. To better understand the nature of these programs, we used multilabel immunocytochemical methods to examine the accumulation of endogenous neuroendocrine products as well as the product of a liver fatty acid binding protein/human growth hormone transgene in enteroendocrine cells located in proximal colonic glands. The results suggest that serotonin, substance P-, glucagon-like peptide-1 (GLP-1)-, peptide tyrosine tyrosine (PYY)-, neurotensin-, and cholecystokinin (CCK)-producing cells can all arise from a single stem cell located within a given gland. Based on pairwise comparison of the coexpression of each of these six products in individual cells as well as their ability to support transgene expression, it appears that the enteroendocrine lineage has two branches; one branch produces substance P and serotonin cells while the other yields GLP-1, PYY, neurotensin, and CCK cells.
Animals↗
Dynorphin-processing endopeptidase in the rat anterior pituitary lactotrophic cell line, GH4C1.
Several peptide hormones and neurotransmitters are produced by cleavage at the monobasic processing sites. An endoprotease capable of cleaving a dynorphin peptide at the monobasic processing site is secreted from the rat anterior pituitary lactotrophic cell line, GH4C1. When characterized by fast protein liquid chromatography using an ion exchange column, the majority of the endoprotease activity elutes as a single symmetrical peak around 0.3 M NaCl. The protease inhibitor profile suggests that the activity is due to putative thiol protease. These enzymatic properties are similar to a monobasic processing enzyme previously found in bovine pituitary and in the rat brain. The secretory pathway which contains the enzyme activity in GH4C1 cells was characterized by stimulation of secretion by thyrotropin releasing hormone, forskolin, phorbol ester, or potassium chloride. The secretion of the enzyme activity was substantially increased by these compounds suggesting that the GH4C1 cells secrete the activity via the regulated pathway. A hormonal treatment of the GH4C1 cells which has been previously shown to produce a substantial increase in the number of secretory granules and ir-prolactin has been found in this study to elevate this enzyme activity 2-fold. This increase is similar to that seen in the carboxypeptidase E activity, another putative peptide hormone processing enzyme activity. These data suggest that the peptide processing activity is regulated to a small but significant extent and is coordinately regulated with carboxypeptidase E activity.
Amino Acid Sequence↗
Antimicrobial activity of subinhibitory concentrations of ciprofloxacin against Pseudomonas aeruginosa as determined by the killing curve method and the postantibiotic effect.
This investigation used the postantibiotic effect (PAE) and killing curves to examine the antimicrobial activity of subinhibitory (1/8x, 1/4x and 1/2x MIC) and inhibitory (1x MIC) concentrations of ciprofloxacin against mucoid (M) and nonmucoid (NM) urinary isolates of Pseudomonas aeruginosa. Subinhibitory concentrations (1/8x, 1/4x and 1/2x MIC) of ciprofloxacin produced PAEs with no difference between M and NM strains. For NM strains, those with low MICs (< or = 1.0 mg/l) to ciprofloxacin produced significantly longer PAEs than isolates with high MICs (> 1 mg/l). Killing curve studies demonstrated that subinhibitory concentrations of ciprofloxacin produce little effect (1/8x MIC) or stasis (1/4x and 1/2x MIC) of growth for several hours. Only 1x MIC was bactericidal for several strains. At 1/2x and 1x MIC, bacterial inhibition was greater against NM versus M isolates. The M phenotype of P. aeruginosa reduces killing by ciprofloxacin but not the PAE.
Ciprofloxacin↗