Stability of two-dimensional stringy black hole.
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Journal Article↗
Biomedical subjects
Y Kim
Publications and source records attributed to Y Kim.
Geometric phase in generalized Landau states.
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Journal Article↗
Regulation of neutrophil interleukin 8 gene expression and protein secretion by LPS, TNF-alpha, and IL-1 beta.
Neutrophils are possibly involved in the pathogenesis of various lung diseases through the release of numerous mediators. In the present study, we studied the regulation of IL-8 gene induction and protein secretion in human blood neutrophils. Northern blot analysis revealed that LPS increased IL-8 mRNA levels in neutrophils, with a maximal fivefold increase by 2 h. IL-8 mRNa levels returned to baseline values within 12 h. In contrast, LPS-stimulated monocytes demonstrated a sustained increase of IL-8 mRNA levels for more than 24 h. TNF-alpha, IL-1 beta, and phorbol myristate acetate also increased IL-8 mRNA levels in neutrophils. Immunohistochemical analysis confirmed that IL-8 was localized within stimulated neutrophils. IL-8 secretion by neutrophils and monocytes was quantified using a specific ELISA for IL-8. Resting neutrophils secreted minimal IL-8 activity. However when cells were stimulated with LPS, TNF-alpha, or IL-1B, neutrophils secreted IL-8. IL-8 secretion was most marked during the first 2 h after stimulation and decreased thereafter. In contrast, monocytes maintained a high rate of IL-8 secretion over 12 h. Although a single monocyte secreted 70-fold more IL-8 than did a single neutrophil after 4 h of incubation, the high abundance of neutrophils in peripheral blood made the neutrophil-secreted IL-8 more significant. During the first 2 h, neutrophils secreted approximately 40% of the IL-8 released by monocytes in the same volume of blood. This ratio decreased to 9% after 12 h. Neutrophil-secreted IL-8 may play an autocrine or paracrine role during the initial stage of inflammation.
Cells, Cultured↗
Molecular cloning and characterization of anther-preferential cDNA encoding a putative actin-depolymerizing factor.
A cDNA clone, LMP131A, which is preferentially expressed in mature anther was isolated from a lily cDNA library. Northern blot analysis and plaque hybridization experiments showed that the LMP131A mRNA is present at ca. 0.3% of the mRNA in mature pollen and is not detectable in carpel, petal, floral bud, leaf, or root. The clone contains an open reading frame of 139 amino acid residues which shows greater than 40% sequence identity in a 91 amino acid overlap to animal actin-depolymerizing factors (ADF), cofilin and destrin. The sequences at and near the actin-binding site are most conserved. Using the lily clone as a probe, a cDNA clone, BMP1, was isolated from a mature anther library of Brassica napus. The expression pattern of the BMP1 clone was the same as that of the lily clone. The Brassica anther-preferential clone contains an open reading frame which is 79% identical to the lily LMP131A protein. Southern blot analysis showed that there are one or a few copies of the putative ADF genes in B. napus and Arabidopsis thaliana.
Actin Depolymerizing Factors↗
Arachidonic acid metabolism by isolated and cultured middle ear epithelial cells from the chinchilla.
Thin-layer chromatography was used to examine the metabolism of arachidonic acid and prostaglandins (PGs) in freshly isolated and cultured middle ear epithelial cells from the chinchilla. The freshly isolated cells converted arachidonic acid predominantly to PGE2, while those cells grown in culture for 10 days acquired the ability to convert arachidonic acid to 6-keto-PGF1 alpha, PGD2, and PGE2. Incubation of the isolated cells and primary cultures with acetylsalicylic acid and indomethacin inhibited the formation of these PGs. These findings suggest that studies on the factors regulating arachidonic acid metabolism in middle ear epithelium may help to explain the role of eicosanoids in middle ear secretions, particularly in relation to the pathophysiology of otitis media.
6-Ketoprostaglandin F1 alpha↗
Biochemical characterization of mucous glycoproteins secreted by in vitro chinchilla middle ear epithelial cells.
A method for middle ear epithelial (CMEE) cell culture with active mucus secretory function has been successfully developed, using the chinchilla as an animal model. CMEE cells were dissociated by protease digestion from the middle ear mucosa. The CMEE cells grown in primary culture incorporated [3H]glucosamine into a glycoconjugate after its release into medium. This substance was characterized biochemically as mucin, although the production of mucin by the cells required growth on a substratum of collagen gel. These cultures provide an excellent model for studying factors that regulate synthesis and secretion of glycoproteins in CMEE cells.
Animals↗
An infant with bilateral adrenal neuroblastoma found by mass-screening: report of a case.
A male infant with bilateral adrenal neuroblastoma found by mass-screening is herein reported. The patient presented with almost equal-sized tumors, each remaining confined to the respective adrenal gland without crossing the midline. No other tumorous lesion was evident. The two adrenal tumors had similar histologic features and appeared to have grown concurrently. Such simultaneous occurrence of primary adrenal neuroblastoma is unusual, and appears to reflect the multicentric origin of this tumor.
Adrenal Gland Neoplasms↗
A freshwater bioprobe: Periostracum of the Asian Clam, Corbicula fluminea (Müller) combined with laser microprobe mass spectrometer.
A freshwater bioprobe, combining the Asiatic Clam, Corbicula fluminea (Müller) and the laser microprobe mass spectrometer (LAMMA), can determine anthropogenic chemical contamination of freshwater systems. Laser generated mass spectra from the periostracal layers of clams contaminated with either a salt, potassium bromide, or an aromatic compound, phenol, produce distinctive mass spectral signatures that are different from uncontaminated clams. Uncontaminated clams have characteristic signatures with distinctive spectral peaks less than m/z 41; while exposed clams have many strong peaks well above this m/z. This freshwater bioprobe, using LAMMA to analyze the surface of clams, can be used as a screening tool for monitoring the water-treatment systems, for determining the source of contaminated baseflow and return flow discharge to streams, and for monitoring the water chemistry of a body of water. This system exploits the facility of using the shell instead of soft tissue with the LAMMA and has potential to detect anthropogenically-derived chemical stress.
Journal Article↗
Hypertension, hyperlipidemia, and renal damage.
Experimental studies have demonstrated that a number of factors participate in the progression of renal disease. Systemic and glomerular hypertension have been shown to be critical factors in renal injury. Hyperlipidemia that frequently coexists with renal disease also has been suggested as an important participatory factor in nephron damage. Interestingly, both hypertension and hyperlipidemia seem to evoke glomerular growth, a factor that has also been postulated to be involved in glomerular and tubular destruction. Recently, experimental and clinical data suggest that an important interaction occurs between hyperlipidemia and hypertension. Not only do they frequently coexist, but hypertension dramatically exaggerates hyperlipidemic injury, and hyperlipidemia alters systemic and glomerular vascular production of vasoactive substances which maintain basal vascular tone. Thus, these recent observations underscore the interactive potential of the various risk factors that participate in progression of renal disease. They also suggest that multiple interventional strategies may be needed to optimally prevent progressive nephron loss.
Animals↗
Optimal modulation frequency for amplitude-modulation following response in young children during sleep.
In young children, there appears to be no advantage to recording steady-state response (SSR) at a stimulus rate of 40 Hz. To determine the optimal modulation frequency in auditory SSR evoked by sinusoidally amplitude-modulated (SAM) tones (amplitude-modulation following response: AMFR) in children during sleep and compare response patterns of AMFR at different modulation frequencies while awake with those during sleep, AMFR was examined in 10 adults with normal hearing while awake and during sleep and in 10 young children with normal hearing during sleep. The stimulus was a 1000 Hz, 50 dBnHL SAM tone with a modulation depth of 95%. Modulation frequency was varied from 20 to 200 Hz in 20 Hz steps. Response was determined by phase spectral analysis and the S/N ratio calculated by spectral amplitude at the modulation frequency and noise level around the modulation frequency using fast Fourier transform. Although AMFR was clearly evoked only by a modulation frequency of 40 Hz in adults while awake, AMFRs at modulation frequencies of 80 and 100 Hz were detected during sleep, in addition to 40 Hz AMFR. In children, 40 Hz AMFR was difficult to detect, but response could be clearly detected at higher modulation rates, especially at modulation frequencies of 80 and 100 Hz, compared with response in adults during sleep. Modulation frequencies from 80 to 100 Hz would thus appear optimal for detecting AMFR during sleep in children.
Adult↗
Lovastatin retards the progression of established glomerular disease in obese Zucker rats.
Considerable experimental evidence indicates that hyperlipidemia can induce glomerular injury. The importance of lipids in the progression of established glomerular disease has not been established and is of clinical relevance because of the frequent association of lipid abnormalities with human renal disease. In the present study, 26-week-old hyperlipidemic obese Zucker rats (OZRs) with established nephropathy were treated for a period of 18 weeks with daily injections of the cholesterol synthesis inhibitor lovastatin (4 mg/kg). Compared with control OZRs treated with vehicle, lovastatin-treated OZRs had significantly (P < 0.05) lower serum cholesterol and triglyceride levels throughout the treatment period. Blood pressure and urine albumin excretion in lovastatin-treated OZRs were reduced over the first 12 weeks of therapy, but increased toward the levels in the control OZRs at the end of the protocol. After 18 weeks of therapy, the incidence of glomerulosclerosis in lovastatin-treated OZRs (23.2% +/- 5.8%) was approximately half of that in vehicle-treated OZRs (44.6% +/- 7.7%) (P < 0.05). The reduction in glomerular injury in lovastatin-treated OZRs was not associated with changes in either glomerular area or glomerular macrophage content. In separate experiments, mesangial cells were cultured from glomeruli isolated from 26-week-old proteinuric OZRs. Lovastatin (5 to 40 mumol/L) caused a significant dose-dependent inhibition of serum-stimulated mesangial cell DNA synthesis. The inhibitory effects of lovastatin were completely prevented in the presence of exogenous mevalonate (100 mumol/L). Thus, lovastatin retarded the progression of established glomerular disease in OZRs.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Degradation pathways for recombinant human macrophage colony-stimulating factor in aqueous solution.
Recombinant human macrophage colony-stimulating factor (rhM-CSF) promotes macrophage proliferation and activity. rhM-CSF clinical trials are currently in progress and require a stable, pharmaceutically acceptable dosage form. This report documents pH effects on rhM-CSF degradation profiles in aqueous solution, with an emphasis on identifying degradation products. Thus, highly purified rhM-CSF was maintained at 30 to 50 degrees C in solutions adjusted to pH 2 to 10. Stressed samples were analyzed by SDS-PAGE, reverse-phase HPLC, size exclusion HPLC, scanning microcalorimetry, and murine bone marrow activity. The results show maximal protein stability in the region pH 7 to 8. Degradation product chromatographic and electrophoretic analyses show distinctly different degradation product profiles in acidic versus alkaline solution. For samples stressed in acidic solution, degradation products were isolated chromatographically and electrophoretically. These degradation products were characterized by N-terminal amino acid sequencing, fast-atom bombardment mass spectrometry, and peptide mapping. The results show that the major degradation pathway in acidic solution involves peptide cleavage at two sites: aspartate169-proline170 and aspartate213-proline214. A third potential cleavage site (aspartate45-proline46) remains intact under conditions that cleave Asp169-Pro170 and Asp213-Pro214. In alkaline solution, degradation proceeds via parallel cleavage and intramolecular cross-linking reactions. A beta-elimination mechanism is proposed to account for the degradation in alkaline solution. Consistent with literature observations, the rhM-CSF N-terminal cleavage products retain biological activity.
Alcaligenes↗
Interstitial fibrosis in obstructive nephropathy.
Interstitial fibrosis and tubular basement membrane (TBM) thickening are evident within 16 days of unilateral ureteral obstruction (UUO) in the rabbit, and resemble the changes previously reported in hydronephrotic human kidneys. The cortical interstitial volume fraction in this rabbit model at 16 days is 43.3 +/- 6.1% (+/- 1 SD) in UUO kidneys, 4.9 +/- 3.1% in contralateral kidneys (CLK), and 2.8 +/- 0.8% in kidneys from sham-operated animals (ANOVA, P < 0.0001). Immunohistochemically, UUO is associated with increased interstitial collagens I and III, fibronectin, heparan sulfate proteoglycan and tubulointerstitial nephritis antigen. Aberrant collagen expression is also evident as interstitial collagen IV becomes prominent. Focal, peritubular accumulation of collagens I and II also appear to encircle the TBM. These changes are accompanied by an early, transient increase in renal cortical mRNA encoding the alpha 1 monomers of collagens I, III and IV, implicating increased matrix synthesis in the pathogenesis of obstructive nephropathy. In situ hybridization localized increased expression of alpha 1 (I) and alpha 1 (IV) mRNA to cells in the interstitial space, with clusters of alpha 1(I) positive cells associated with dilated tubules, muscular arteries and the periglomerular interstitium.
Animals↗
Structural-functional relationships in type I mesangiocapillary glomerulonephritis.
We quantitated glomerular and cortical interstitial structures in nine type I mesangiocapillary glomerulonephritis (MCGN) patients aged 6 to 20 years whose creatinine clearance (CCr) was 10 to 129 ml/min/1.73 m,2 as compared to age-matched normal controls. Mean glomerular volume and mesangial volume fraction [Vv(mes/glom)] were increased and the percentage of the capillary endothelial circumference which was defined as filtration surface was decreased in type I MCGN patients. Vv(mes/glom) was inversely related to filtration surface area per glomerulus (r = -0.73, P < 0.05) and directly to volume density of cortical interstitium [Vv(int/cortex)] (r = +0.90; P < 0.01). Vv(mes/glom) (r = -0.87; P < 0.01), filtration surface area per glomerulus (r = +0.83; P < 0.01) and Vv(int/cortex) (r = -0.86; P < 0.01) were correlated with CCr. Thus, in type I MCGN, measures both of glomerular and of cortical interstitial structure are highly correlated with glomerular function.
Adolescent↗
Inhibitory effects of hydrolyzable tannins on Ca(2+)-activated hyaluronidase.
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Calcium↗
Free radical generation coupled with arachidonate lipoxygenase reaction relates to reoxygenation induced myocardial cell injury.
OBJECTIVE: The role of arachidonate lipoxygenase activity in reoxygenation induced cell injury in adult canine cardiac myocytes was investigated. METHODS: The production of hydroxyeicosatetraenoic acids (HETEs), which are lipoxygenase metabolites, was measured with high pressure liquid chromatography in canine cardiac myocytes cultured under hypoxic conditions and then reoxygenated. Free radical generation was evaluated by electron paramagnetic resonance spectroscopy with a spin trapper, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and luminol enhanced chemiluminescence emission. Cell injury was estimated in terms of morphological changes and release of intracellular enzymes. Morphological damage to myocytes was quantified in terms of the percentage of hypercontracted "round" cells. The effects of nordihydroguaiaretic acid, AA-861, mepacrine, indomethacin, aspirin, alpha tocopherol, and 2-0-octadecylascorbic acid (CV-3611) on lipoxygenase metabolism, free radical generation and cell injury were also assessed. RESULTS: Cardiac myocytes produced 5-HETE and 12-HETE at less than 0.1 ng.mg-1 protein under normoxic conditions. Production of HETE was greatly increased at five hours of reoxygenation after 45 minutes of hypoxia [5-HETE = 12.0(SEM 0.5), 12-HETE = 23.6(1.1) ng.mg-1 protein]. Both DMPO-OH adduct generation and chemiluminescence emission were considerably increased after one to three hours of reoxygenation, although they increased only slightly after 45 minutes of hypoxia. After five hours of reoxygenation, long rod cells gradually became deformed; 92.0% of the cells were converted to hypercontracted "round" cells. Cell injury and HETE production were significantly suppressed by nordihydroguaiaretic acid (10 microM), AA-861 (2 microM), and mepacrine (10 microM). Indomethacin (10 microM) and aspirin (50 microM) enhanced cell injury and HETE production. alpha Tocopherol and CV-3611 greatly suppressed cell injury and free radical generation, but not HETE production. CONCLUSION: The arachidonate lipoxygenase metabolic pathway may have an important role in reoxygenation induced myocardial cell injury in adult cardiac myocytes, possibly because of the generation of free radicals.
Animals↗
Adult emergence patterns in Musca autumnalis (Diptera: Muscidae).
Adult emergence patterns were investigated in four lines of face flies, Musca autumnalis De Geer, in a 16:8 (L:D) h photoperiod and corresponding 30:25 degrees C thermo-period. Most emergence occurred in a specific time interval ("emergence gate") that began at 2000 hours and continued until 1200 hours. A cohort of puparia completed emergence in two or three consecutive emergence gates. The four lines showed different median times and rates of emergence. Laboratory rearing seemed to select progeny of earlier median times and faster rates of emergence. F1 progeny of the two lines showed patterns of emergence intermediate between those of the parents. Female flies tended to eclose earlier than males in all lines.
Analysis of Variance↗
Gastric acid production, iron status and dietary phytate alter enhancement by meat of iron absorption in rats.
This study was designed to determine whether gastric acidity, added phytate or iron status significantly influenced the effects that dietary proteins have on iron absorption. Rats were fed test meals of wheat cereal, with and without an added dietary protein (beef, pork, chicken, fish or egg white), by gavage. The influences of phytate and gastric acid were investigated by adding sodium phytate to the test meals and by treating the rats with cimetidine to inhibit gastric acid production. Iron status was altered by dietary regimens. Significant (P < 0.05) effects of the proteins were determined by comparison of the various protein-containing meals to control meals of cereal or cereal + phytate, as appropriate. Gastric acidity, phytate and iron status were all confirmed as factors significantly affecting iron absorption. Beef, pork and chicken enhanced iron absorption, but only when phytate had been added to the meals and only in iron-deficient rats. Enhancement by meat was sufficient to overcome the inhibition by phytate. Fish was an inhibitor or enhancer in cimetidine-treated, iron-deficient rats, depending on the absence or presence of phytate, respectively. Egg white inhibited absorption from cereal meals in cimetidine-treated, iron-deficient rats.
Absorption↗