This study was performed to investigate the effect of endotoxin to the CCl4-induced liver injury. Twelve Sprague-Dawley rats were intraperitoneally injected 1.6 g/kg CCl4 as control group. Another 24 rats were orally administrated 300 mg/kg of neomycin at 16 and 3 hours prior to CCl4 injection as experimental group. Twelve among them were intraperitoneally infected 1.0 mg/kg of endotoxin(E-Coli, 0111:B4, No L-2630, lipopolysaccharide, Sigma, USA) and CCl4 simultaneously for offsetting neomycin effect. The rats were sacrificed at 1, 4, 10, and 24 hours after CCl4 injection. The liver tissues from all experimental groups were observed by light and electron microscopy. The results obtained were summarized as follows: In the CCl4 only group, the hepatocytes revealed sweling of ER and mitochondria with many lipid droplet in the cytoplasm. Focal cellular necrosis was seen at the later phase. The Kupffer cells were activated and showed many cytoplasmic processes, secondary lysosomes, and vaculoles. The endothelial cells were edematous. Several neutrophils, platelets, and microthrombi were scattered in the sinusoid. In the neomycin-CCl4-endotoxin administrated group, both hepatocytic destruction and intrasinusoidal microthrombi formation were more pronounced. In the neomycin pretreated group, the hepatocytes revealed mild cellular destruction without necrosis. There is no intrasinusoidal microthrombi. According to these results, it would be concluded that the small dosage of gastrointestinal tract-derived endotoxin affects to the liver injury caused by CCl4. The synergistic effects of CCl4 and gastrointestinal tract-derived endotoxin which can not be detoxified by damaged Kupffer cells, may be more important in the pathogenesis of CCl4-induced liver injury.
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Chronic deposition of uric acid in the kidney can lead to progressive tubulointerstitial injury with granuloma formation. We hypothesized that uric acid crystal deposition may induce granuloma formation by stimulating local expression of macrophage migration inhibitory factor(MIF), which is a known mediator of delayed type hypersensitivity(DTH). A model of acute uric acid nephropathy was induced in rats by the administration of oxonic acid (an inhibitor of uricase) together with uric acid supplements. Kidney tissue examined at 35 days showed widespread tubulointerstitial damage with intratubular uric acid crystals deposition and granuloma formation. Tubules within the areas of granuloma showed a six-fold increase in MIF mRNA compared to uninvolved areas by in situ hybridization. Moreover, the areas of increased MIF mRNA expression correlated with sites of dense accumulation of macrophages and T cells. Control rats fed a normal diet had no discernible evidence of renal disease by routine light microscopy and minimal tubular expression of MIF mRNA and protein. These data suggest that intrarenal granulomas in urate nephropathy may be the consequence of a crystal induced DTH-like reaction mediated by MIF.
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Potassium(K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. It has been established that chronic potassium depletion is associated with a remarkable hypertrophy of the outer medullary collecting duct of the kidney. But, there are no morphological studies regarding the intercalated cells during the chronic changes of potassium diet. Electron microscopy was performed to observe the morphological alterations of the intercalated cell of the entire collecting duct in response to chronic changes of potassium diet in rat kidney. By electron microscopy, the characteristic features of normal type A intercalated cell of the cortical collecting duct included numerous micro-projections of the apical plasma membrane, complicated basal infolding, apical cytoplasmic tubulovesicles, evenly distributed mitochondia, and centrally located nucleus. In potasium-depleted type A intercalated cell, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were uncomplicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Type A intercalated cell of potassium-loading after restriction was found to be almost normal except longer microprojections and increased mitochondria. The characteristic features of normal intercalated cell of the outer medullarycollecting duct(OMCD) included relatively short micro-projections of the apical plasma membrane, uncomplicated basal infoldings, apical cytoplasmic tubulovesicles, and apically distributed mitochondia. In comparison with normal, potassium-depleted intercalated cell of OMCD was hypertrophy, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almost disappeared, mitochondria were increased in number, and several lysosomes were appeared. Intercalated cell of OMCD of potassium-loading after restriction was found to be almost normal except increased cell size, longer microprojections, and increased mitochondria and lysosomes compared to control. The characteristic features of normal intercalated cell of the inner medullary collecting duct (IMCD) included very short and scant microprojections of the apical plasma membrane, uncomplicated basal infoldings,apica cytoplasmic tubulovesicles, evenly distributed mitochondia, and some lysosomes. In potasium-depleted intercalated cell of IMCD, cell size was prominently increased, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Intercalated cell of IMCD of potassium-loading after restriction was found to be almost normal except increased cell size and increased microprojections in number and length compared to control. These results suggest that intercalated cells adapt through morphological changes to preserve potassium balance during chronic changes of potassium diet.
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Diuretics are natriuretic agents which inhibit sodium reabsorption at their major site of action on the renal tubules and increase the excretion of sodium and combined anions. Increment of urine volume is the secondary to the natriuretic effects. Diuretic resistance occurs that threshold dose of diuretics is higher than that of other patients. It is frequently manifested among the edematous patients such as those with the nephrotic syndrome. Prolonged use of diuretics decreases the natriuretic effect of diuretics, which is called diuretic tolerance. This is important adaptations of distal nephron segment. To elucidate the mechanism of diuretic resistance, 1 mg of bumetanide was given to the nephrotic syndrome(NS) patients group and control group, respectively. The peak plasma concentration was delayed in NS patients. The proportion of urine free bumetanide for 24 hours was 73% in NS patients but 100% in control group. The ratio of urine volume and amount of Na+ and Cl - for 24 hours to the total and free urine bumetanide was decreased in NS patients. The study suggests that pharmacokinetic and pharmacodynamic changes of the diuretics induce the diuretic resistance. To determine the additive diuretic effect of albumin to the action of the furosemide, 160 mg of furosemide was administered intravenously with albumin in NS patients. Simultaneous infusion of albumin and furosemide did not enhance the diuretic effect of furosemide pharmacodynamically and pharmacokinetically. Albumin preinfusion 30 minutes before furosemide administration potentiates the diuresis, but natiuresis and pharmacokinetics were not changed. Semiquantitative immunoblotting of rat kidneys was carried out to investigate whether chronic diuretics adminstration induces changes in the abundance of Na+ transporters in distal nephron. Furosemide infusion increased cortical and outer medullary abundances of Na+-Cl- cotransporter(TSC) and all 3 subunits of the epithelial sodium channel(ENaC). Hydrochlorothiazide infusion increased abundances of some kinds of subunits of ENaC. These increases in the abundances of Na+ transporters may account for the generation of diuretic tolerance.These data suggest that to overcome the diuretic resistance or tolerance, diuretic dose increment over the threshold level and more frequent administration of the diuretics are recommended. Diuretic combinations are also proposed. Addition of albumin to augment the diuretics effect ought to be considered cautiously.
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No abstract available.
Animals ; Rats*

This study was carried out to investigate the mechanisms of interstitial pulmonary fibrosis of rats after the intratracheal administration of bleomycin. Both lungs after bleomycin injection were examined by light and electron microscopy. The results are as follows: Light microscopically, 1 or 2 weeks after bleomycin injection acute and chronic inflammatory infiltrates and edema in the interstitium and alveolar spaces were observed. Proliferation of alveolar type II pneumocytes was also found at 4 to 6 weeks after bleomycin injection, chronic inflammatory infiltrates with interstitial fibrous thickening were noted. Electron microscopically, the number of type II pneumocytes and irregular lamellar bodies were increased and blunted microvilli were noted at 2 weeks. 4 to 8 weeks, proliferation of fibroblasts with deposition of abundant collagen fibrils in the thickened interstitium revealing irregular or collapsed alveolar spaces were observed. Based on these findings, it can be concluded that bleomycin-induced interstitial pulmonary fibrosis is considered to pass from an early acute inflammation of the interstitium and alveolar spaces to an interstitial fibroblast proliferation and collagen deposition to the length of the period after injection.
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In an attempt ultrastructural study of alcohol-induced gastric mucosal change, we selected sixty Sprague-Dawley rats. The rats were administrated with 4 ml of 10% and 40% ethanol enterically and examined by light and electron microscopy. Light microscopically, the thickness of the mucus layer of both 10% and 40% ethanol groups was decreased. The antral mucosa revealed focal inflammatory infiltrates, disturbed glandular arrangements, and significant decrease of mucosal thichness and proper glands. On scanning electron microscopy, flattened or swollen mucosal epithelium and irregularly distributed gastric pits were seen in both experimental groups, and these changes were more severe in the groups of higher concentration and longer duration. On transmission electron microscopy, mitochondrial abnormalities with myelin-like materials and dilatation of endoplasmic reticulum and cytoplasmic blebs were observed. Also the mucus cells show significantly decreased mucus globules, increased fat vacuoles, and large autophagic vacuoles. These alterations were similar to those produced by ethanol in the liver and small intestine. This study indicates that, prolonged administration of ethanol induced chronic gastritis, especially chronic atrophic gastritis.
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Several growth factors and polypeptides are not commonly yet used for regenerators of bone tissue or alveolar bone because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many natural medicines, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, antiinflammatory and regenerative potential of periodontal tissues. Olibanum, Myrrha, Phlomis Radix, and Cimicifugae Rhizoma have been traditionally used as a drug for treatment of bone disease in oriental medicine. The objective of this study was to examine the ability of alkaline phosphatase(ALP) synthesis of rat calvarial osteoblast(MC3T3-E1) when several natural medicines were supplemented. MC3T3-E1 cells were cultured with alpha-MEM(negative control), dexamethasone(positive control), and each natural medicines for 3 and 5 days. And then ALP synthesis was measured by spectrophotometer for enzyme activity and by naphthol AS-BI staining for morphometry. All of the natural medicines induced higher activity of ALP synthesis than the negative controls. Especially Olibanum induced the higher activity than the positive controls(p<0.05). In the aspects of culturing time, except Cimicifugae Rhizoma, the natural medicines induced higher activity of ALP synthesis at 5 days than at 3 days(p<0.05). In morphometry, all of the natural medicines showed statistical significance compared to the negative control(p<0.05). Myrrha and Phlomis Radix showed larger positively stained area at 5 days than at 3 days, whereas the others did not showed the difference between at 5 and at 3 days(p<0.05). These results indicate that several natural medicines have an inducing ability of ALP synthesis in MC3T3-E1 cells.
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Amiodarone, an antiarrhythmic drug, may exert pulmonary toxicity in some patients but the pathogenesis is not clear. This study was carried out to investigate the pathogenetic mechanism of pulmonary injury induced by amiodarone at dose of 100 mg/kg/day given to rats by intraperitoneal injection for 3 weeks. And the preventive effects of concomitantly injected steroid (10 mg/kg/day) on amiodarone induced pulmonary injury was also studied using bronchoalveolar lavage, light microscopy and transmission electron microscopy. The results obtained were summarized as follows: Mild lymphocytosis of bronchoalveolar lavage fluid was found in all experimental groups. Intracytoplasmic lamellar body formation was found in all types of pulmonary cells and type II pneumocytes revealed the earliest abnormal lamellar body formation. The capillary endothelial cells showed cellular swelling and detachment from underlying basement membrane at early phase of experiment and the edema of alveolar wall and interstitium were noted. Interstitial fibrosis and proliferation of type II pneumocytes were noted at late phase. The lungs of steroid injected groups revealed accumulation of lamellar bodies in all types of pulmonary cells but interstitial fibrosis was not occurred. These findings support the concept that amiodarone is responsible for a drug-induced phospholipidosis and directly toxic to pulmonary endothelial and epithelial cells. And steroid may regress the progression of amiodarone induced pulmonary injury.
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The purpose of this study was to investigate the inhibitory role of vitamin A with respect to activation of Ito cells in fibrosis of the rat liver induced by common bile duct ligation(CBDL). The liver was examined by immunohistochemical staining for a-smooth muscle actin,the known marker of activated Ito cells, and light and electron microscopy after CBDL andCBDL with intraperitoneal injection of retinoic acid (Sigma, USA) 1 mg/Kg in 3 times per week. The results were sumrrlerized as follows: After CBDL, the bile ductules were markedly proliferated in the periportal areas extending toterminal hepatic veins. Interstitial fibrosis and inflammatory cell infiltration appeared, however,cholestasis was minimal. Retinoic acid treatment with CBDL decreased bile ductular proliferationand interstitial fibrosis compared to CBDL only. After CBDL, proliferated and activated Ito ceIs showing positive reaction in smooth muscle actin were present in the periductular andperisinusoidal areas, and areas of increased interstitial fibrosis. Activated ito cells weredecreased in number after CBDL with vitamin A treatment. Electron microscopically,intracytoplasmic fat droplets and the cytoplasmic processes of Ito cells were decreased afterCBDL. Myofibroblasts were frequently appeared in the interstitial fibrosis after CBDL. But,intracytoplasmic fat droplets of Ito cells were well preserved, and myofibroblasts were found lessfrequently after CBDL with vitamin A treatment. The results suggest that vitamin A plays an inbitory role in the activation and fibrogenesis ofIto cells after CBDL.
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