No abstract available.
Animals ; Rats*

The surface characteristics of titanium have been shown to have an important role in contact ossseointegration around the implant. Anodizing at high voltage produces microporous structure and increases thickness of surface titanium dioxide layer. The aim of present study was to analyse the response of rat calvarial osteoblast cell to commercially pure titanium and Ti-6Al-4V anodized in 0.06 mol/l beta-glycerophosphate and 0.03 mol/l sodium acetate. In this study, rat calvarial osteoblasts were used to assay for cell viability and cell proliferation on the implant surface at 1, 2, 4, 7 days. 1. Surface roughness was 1.256micrometer at 200V, and 1.745micrometer at 300V. 2. The thickness of titanium oxide layer was increased 1micrometer with the increase of 50V. 3. The proliferation rate of osteoblastic cells was increased with the increase of the surface roughness and the thickness of titanium oxide layer. 4. There was no difference in cell viability and cell proliferation between commercially pure titanium and Ti- 6Al-4V anodized at the same condition. In conclusion, the titanium surface modified by anodizing was biocompatible, produced enhanced osteoblastic response. The reasons of enhanced osteoblast response might be due to reduced metal ion release by thickened and stabilized titanium dioxide layer and microporous rough structures.
Rats ; Animals

The ultimate objective of periodontal treatment is to get rid of an on-going periodontal disease and further regenerate the supporting tissue, which is already destroyed, functionally. Currently, the bone grafting operation using various kinds of bone grafting materials and the operation for induced regeneration of periodontal tissue using the blocking membrane are performed for regeneration of the destroyed periodontal tissue. However, there are respective limitations Galenical preparations, which are used for regeneration of periodontal tissue, has less risk of rejective reaction or toxicity that may be incidental to degradation and their effect is sustainable. Thus, in case they are applicable to a clinic, they can be used economically. Chitosan has such compatibility, biological actions including antibacterial activity, acceleration of wound treatment, etc., and excellent mechanical characteristics, which has recently aroused more interest in it. Also, it has been reported that it promotes osteogenesis directly or indirectly by functioning as a matrix to promote migration and differentiation of a specific precussor cell (for example, osteoblast) and further inhibiting the function of such a cell as fibroblast to prevent osteogenesis. In this study, the pure chitosan solution, which was obtained by purifying chitosan, was used. However, since this chitosan is of a liquiform, it is difficult to sustain it in a defective region. It is, therefore, essential to use a carrier for delivering chitosan to, and sustaining it gradually in the defective region. In the calvarial defect model of the Sprague-Dawley rat, it is relatively easy to maintain a space. Therefore, in this study, the chitosan solution with which ACS was wetted was grafted onto the defective region. For an experimental model, a calvarial defect of rat was selected, and a critical size of the defective region was a circular defect with a diameter of 8 mm. A group in which no treatment was conducted for the calvarial defect was set as a negative control group. Another group in which treatment was conducted with ACS only was set as a positive control group (ACS group). And another group in which treatment was conducted by grafting the pure chitosan solution onto the defective region through ACS which was wetted with the chitosan solution was set as an experimental group (Chitosan/ACS group). Chitosan was applied to the Sprague-Dawley rat's calvarial bone by applying ACS which was wetted with the chitosan solution, and each Sprague-Dawley rat was sacrificed respectively 2 weeks and 8 weeks after the operation for such application. Then, the treatment results were compared and observed histologically and histometrically. Thereby, the following conclusions were obtained. 1. In the experimental group, a pattern was shown that from 2 weeks after the operation, vascular proliferation proceeded and osteogenesis proceeded through osteoblast infiltration, and at 8 week after the operation, ACS was almost absorbed, the amount of osteogenesis was increased and many osteoid tissue layers were observed. 2. At 2 weeks after the operation, each amount of osteogenesis appeared to be 8.70.8 %, 13.62.3 % and 4.80.7 % respectively in the experimental group, the positive control group and the negative control group. Accordingly, it appeared to be higher in the Experimental group and the positive control group than in the negative control group, but there was no significant difference statistically (p<0.01). 3. At 8 weeks after the operation, each amount of osteogenesis appeared to be 62.26.1 %, 17.42.5 % and 8.21.4 % respectively in the experimental group, the positive control group and the negative control group. Accordingly, it appeared to be substantially higher in the experimental group than in the positive control group and the negative control group, and there was a significant difference statistically (p<0.01). As a result of conducting the experiment, when ACS was used as a carrier for chitosan, chitosan showed effective osteogenesis in the perforated defective region of the Sprague-Dawley rat's calvarial bone.
Rats ; Animals

No abstract available.
Animals ; Rats*

The cholestasis are defined as blockade or secretory distrubance of bile and appearance of bile in hepatocytes, Kupffer cells and biliary passages, usually associated with dilated bile canaliculi. Intra-and extraheptic cholestasis were induced by 17-ethinyl estradiol, or chlorpromazine hydrochloride and by ligation of bile duct to investigate the mechanism of the hepatic injury, ultrastructural changes of liver and alterations of liver function. The results obtained were as follows. 1) Functional and histological changes of intra-and extrahepatic cholestasis differed in various experimental groups. The liver weight is increased in 17-ethinyl estradiol treated group and ligation of bile duct group (5.6+/-0.15, P<0.001, 5.3+/-0.19 gm/100 gm body weight, P<0.001). The common features of intra-and extrahepatic cholestasis were double membrane bounded amorphous vesicular material infiltrations in the cytoplasm of hepatocyte, partial loss of microvilli of bile canaliculi, anf focal thickening of pericanalicular ectoplasm on electron microscopy. 2) Intrahepatic cholestasis induced by 17-ethinyl estradiol show significantly increased serum level of alkaline phosphatase and total bile aicd (134.0+/-16.82 IU/L, 29.5+/-4.68 umol/l). Kupffer cell proliferation and focal cytoplasmic degradation with myelin figures are characteristic features on electron microscopy. Chlorpromazine hydrochloride induced intrahepatic cholestasis show increased serum level of AST, ALT, Cholesterol and bilirubin (156.9+/-11.32, 49.0+/-2.83 IU/L, 59.3+/-6.73 mg/dl, 1.8+/-.043 mg/dl). Inflammatory cell infiltration, chiefly lymphocytes and esoinophils are seen in periportal area. Prominent vesiculation and vacuolations of smooth endoplasmic reticulum are characteristic feature on electron microscopy. 3) Extrahepatic cholestasis induced by ligation of bile duct show increase serum level of AST, ALT, GGT, cholesterol, total bile acid, and bilirubin (290.2+/-50.24, 171.5+/-47.17, 159.3+/-24.54, 33.7+/-1.47 IU/L, 86.6+/-9.18 mg/dl, 246.6+/-27.34 umol/l, 13.9+/-0.83 mg/dl). Light microscopically, morphologic alterations are feathery degeneration of hepatocytes, proliferation of bile ducts, bile infarct and prominent intracytoplasmic lipid droplets. Electron microscopically, electron dense acidophilic body, bile casts and complete loss of microvilli are seen in dilated bile canaliculi. Also noted are hypertrophy of cannalicular ectoplasm. Finely granular materials are infiltrated in degenerative cytoplasm.
Rats ; Animals

An experimental studies were carried out to observe the protective effects of malotilate, a new antihepatotoxic agent, on the chronic hepatic injury induced by CCl4 with or without ethanol. The rats used weighed about 200g were divided into 2 groups, 4 weeks & 8 weeks. Each group was given by orally with malotilate, 100 mg/kg, once a day, and was injected by subcutaneously with CCl4 1.5 mg/kg in a mixture with olive oil twice a week. Aqueous ethanol (20%) was administered in drinking water daily. The serochemical and histopathological studies were carried out in each experimental group. The results were as follows: 1. The chronic liver injuries induced by CCl4 with or without ethanol were significantly ameliorated by normalize serum values GOT, GPT. Alkaline phosphatase, Cholesterol, HDL-Cholesterol, and gamma glutamyl transpeptidase. 2. In Group of 4 weeks, malotilate manifested protective effects by significant inhibition of fatty changes, spotty necrosis and fibrosis in CCl4-intoxicated liver with or without additional ethanol. 3. In group of 8 weeks, malotilate significantly imoproved fatty changes, fibrogenic activity in the group administered with CCl4, followed by ethanol.
Rats ; Animals

This study was carried out to investigate the ultrastructural findings of rats after administration of 0.5% lead acetate with drinking water. The Sprague-Dawley rats were divided into control and experimental groups. The control group was composed of 12 rats and was orally administered with 0.5% sodium acetate. The experimental group was composed of 36 rats and orally administered with 0.5% lead acetate. Two rats in the control group and four rats in the experimental group were sacrificed on day 2, and week 1, 2, 4, 6 and 8 after administration. The kidney was extirpated and examined by electron microscopy. The results obtained were as follows: The blood lead concentration in the experimental group began to increase from the second day after administration and it increased gradually until the 6th week and it decreased at the 8 week. The urinary excretion of delta-ALA also increased from the secondary and gradually increased up to the 8th week. On electron microscopic examination, the proximal tubular cells showed fat droplets, dilatation of the endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies and intranuclear inclusion bodies. All these findings peaked at the eighth week after administration. Ultrastructural findings after Timm sulphide silver reaction revealed the lead granules in the proximal tubular lumen and between the microvilli of the proximal tubular cells without membrane-bounded. It can be concluded that most of the changes of micro-organelles are compatible with degenerative changes of lead exposure and passive diffusion of lead granules are involved in the proximal tubular cells.
Rats ; Animals

To investigate the morphologic evidence of acute renal failure by folate, histological, histochemical (PAS), enzyme histochemical (Na-K-ATPase, G6PD, and ALP), and ultrastructural studies were performed. The results are as follows: l) Oliguria was most severe 3 hours after folate and the urine volume was 24.8% that of the control group. 2) Histologically, dilatation of tubules, degeneration and focal necrosis of the cortical tubules, and PAS(+) droplets in the tubular lumen were noted. And also frequent mitoses, mild interstital connective tissue proliferation, and neutrophilic infiltrates were observed in the late stage. 3) On enzyme histochemical examination, the activities of Na-K-ATPase and ALP were decreased, but G6PD activity was increased in comparison with the control group. 4) The ultrastructural studies revealed cytoplasmic vacuoles, apical cytoplasmic blebbing, dense bodies, mildly swollen mitochondria, dilated endoplasmic reticulum, loss bf brush border of the proximal tubules, and loss of microvilli of the thin limb of Henle's loop. Later, marked attenuation or loss of infoldings of basal plasma membrane of the cortical tubules was recognized. According to above results, the cause of acute renal failure by late is thought to be the injuries of tubular epithelial cells including sodium pump secondary to tubular obstruction.
Rats ; Animals

The toxicity and adrenostatic effect of o,p'-DDD, a derivative of the insecticidal DDT, on the adrenal cortex were well known. It known that the toxicity was based on the blocking of steroid biopsynthesis when cholesterol was converted to pregnenolone. Lysodren(R) was also known to be capable of producing a regression of adrenocortical carcinoma and its metastases, and this drug became one of useful choice for the treatment of unoperable adrenocortical carcinomas. Recently, fine structural effect of o,p'-DDD on the adrenocortical carcinoma show that the mitochondria is the primary target organelle. o,p'-DDD was dissolved in corn oil and it was orally administered for 28 days to investigate the ultrastructural effects of zona fasciculata of rat adrenal cortex. The results obtained were as follow: 1) The body weight was decreased after feeding o,p'-DDD. 2) Light microscopic examination showed no remarkable change except increased fine lipid droplets of zona fasciculata in group I (o,p'-DDD 75 mg/kg feeding). Moderately increased intracytoplasmic lipid droplets and pyknotic nuclei bearing membrane indentations were seen in group II (o,p'-DDD 150 mg/kg feeding). Large sized lipid droplet aggregates, pyknotic nuclei with severe nuclear membrane indentations and karyorrhexis in focal area were evident in group III. 3) Immunohistochemical staining for ACTH in pituitary gland showed increasing number of ACTH secretory cell and increasing intensity of staining property according to the dosage of o,p'-DDD. 4) Ultrastructural examination showed increased intracytoplasmic lipid droplets and mild increased peroxisome. There was no remarkable ultrastructural changes in mitochondria in group I. Moderately increased lipid droplets and clusters formation, compressed mitochondria, partial disappearance of mitochondrial cristae, increased peroxisome and nuclear membrane indentations were seen in group II. In group III, nuclear membrane showed prominent indentation. Numberous cytoplasmic vacuolation, double membrane ring in mitochondria, disappearance of mitochondrial cristae, myelin figure formation in mitochondrial matrix, and fatty changes in mitochondrial matrix were seen. These findings showed that the primary target organelle of attack by o,p'-DDD on zona fasciculata of adrenal gland in rat is mitochondria and it was developed from double ring formation in mitochondrial matrix.
Rats ; Animals

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.
Rats ; Animals