Biomedical subjects

S Miyauchi

Publications and source records attributed to S Miyauchi.

At least 19 recordsLinked to original sources

PubMed1995

Proliferating activity of dermal fibroblasts in keloids and hypertrophic scars.

Monoclonal antibodies were used to demonstrate proliferating cell nuclear antigen (PCNA) and Ki-67 antigen of dermal fibroblasts in formalin-fixed, paraffin-embedded tissue sections of keloids, hypertrophic scars and normal skin. PCNA-stained fibroblasts were more pronounced than Ki-67, which showed only scanty Ki-67-positive fibroblasts. The mean density of dermal fibroblasts was significantly higher in keloids and hypertrophic scars than in normal skin (p < 0.01). The proliferating activity of fibroblasts detected by PCNA was significantly higher in keloids than in hypertrophic scars or normal skin (p < 0.01). The mean densities and the proliferating activities were apparently not correlated with the age of the patient. This indicates that keloids, with higher density and proliferating activity of dermal fibroblasts, continue to increase their volume and invade the surrounding tissue, while hypertrophic scars, with higher density and lower proliferating activity, show a tendency towards spontaneous regression.

Adolescent↗

PubMed1992

Measurement of plasma membrane potential in isolated rat hepatocytes using the lipophilic cation, tetraphenylphosphonium: correction of probe intracellular binding and mitochondrial accumulation.

The lipophilic cation tetraphenylphosphonium (TPP+) has been extensively utilized as the probe for the membrane potential (Vm) in various cells. For application to mammalian cells, however, two serious problems require resolution: (1), correction of TPP+ binding to intracellular constituents and (2), estimation of the considerable TPP+ accumulation in mitochondria. We propose here a simple corrective method for the TPP+ binding and its accumulation. TPP+ distribution is assumed as: (1), two compartments (a cytosolic and a mitochondrial space); (2), a proportional relationship between TPP+ bound amount and its unbound concentration in each compartment. We theoretically derived the simple equation: Vm = - RT/F ln(C/Mphys ratio/C/Mabol ratio) where R, T and F have their usual thermodynamic significance. Here, the C/M ratio is defined as the ratio of TPP+ concentration of apparent intracellular to extracellular space. The suffixes phys and abol, respectively, mean the physiological and solely Vm-abolished conditions. This equation was checked with hepatocytes, because estimating hepatocytes Vm with TPP+ distribution is not considered possible because of the relatively high mitochondrial content. The selective Vm abolition was achieved by permeabilization with 20 microM of amphotericin B. The Vm value was, thus, estimated to be -38.6 +/- 0.3 mV, compatible with those obtained with microelectrodes in other laboratories. Vm in hepatocytes is composed of transmembrane K+ diffusion potential (-20.6 +/- 0.3 mV) and electrogenic Na+/K(+)-ATPase (-19.6 +/- 0.4 mV). Addition of rheogenic L-alanine caused a transient but significant depolarization (from control to -34 +/- 0.3 mV). These results taken together indicate that hepatocyte Vm can be accurately determined with the present simple method, so that it may possibly be applicable to the evaluation of Vm in other mammalian cells.

Amphotericin B↗

PubMed1992

In archaebacteria, there is a doxorubicin efflux pump similar to mammalian P-glycoprotein.

We selected for study an anthracycline-resistant mutant from the archaebacteria Haloferax volcanii. This resistance was reversed by a Ca(2+)-channel antagonist, nifedipine (NDP). This resistance and its reversal by NDP suggest P-glycoprotein (Pgp) to be responsible for maintaining an anticancer drug concentration below the cytotoxic level. Using rhodamine 123 (RH123) as a substrate for Pgp, we then examined whether the resistance to anthracyclines in this bacteria might involve a Pgp-like anthracycline efflux pump. RH123 accumulation by the bacteria was determined with flow cytometry. A steady-state RH123 accumulation by the resistant cells revealed approx. one-fifteenth of that by the wild-type cells, which could be remarkably enhanced by NDP. The other modulators of Pgp, diltiazem and verapamil, also enhanced RH123 accumulation in resistant cells. The uncoupler FCCP completely restored RH123 accumulation in resistant cells to the wild-type cell level. RH123 unidirectional efflux from resistant cells after its preloading revealed much greater than that from wild-type cells, which was remarkably inhibited by FCCP. These confirmed that RH123 low accumulation involves its active efflux mechanism. Taken together, the present study indicated that lower evolutionary archaebacteria might also express a Pgp-like protein very similar to mammalian Pgp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Quantitation of chondroitin 4-sulfate and chondroitin 6-sulfate in pathologic joint fluid.

OBJECTIVE: To investigate the correlation between joint disease and the composition of chondroitin sulfate in the joint fluid, unsaturated disaccharide isomers of chondroitin 4-sulfate (delta di-4S) and chondroitin 6-sulfate (delta di-6S) were measured in joint fluids obtained from patients with osteoarthritis (OA), rheumatoid arthritis (RA), or traumatic arthritis (TA). METHODS: These pathologic joint fluids were digested with chondroitinase ABC, and the delta di-4S and delta di-6S produced were determined by high performance liquid chromatography combined with fluorometry. RESULTS: Total content of delta di-4S plus delta di-6S was 71.8 +/- 30.0 nmoles/ml (mean +/- SD) in OA, 55.4 +/- 29.3 nmoles/ml in RA, and 211 +/- 149 nmoles/ml in TA joint fluids. The ratio of delta di-6S to delta di-4S was 3.81 +/- 0.992 in OA, 1.13 +/- 0.527 in RA, and 5.75 +/- 2.46 in TA joint fluids. Differences between groups were statistically significant. CONCLUSION: These results strongly suggest that the levels of chondroitin sulfate isomers and the delta di-6S: delta di-4S ratio in joint fluid reflect the proteoglycan metabolism of joint tissues, particularly of articular cartilage; hence, they could be used to diagnose joint diseases and to predict articular cartilage destruction from such joint diseases.

Aged↗

PubMed1992

'Albumin-mediated transport phenomenon' observed for ligands with high membrane permeability. Effect of the unstirred water layer in the Disse's space of rat liver.

In this paper, we offer experimental evidence of the rate-limiting diffusion of ligands through the unstirred water layer (UWL) as an explanation for the so-called albumin-mediated transport phenomenon. The relative membrane permeability of various ligands was first evaluated using isolated rat hepatocytes. Then, the effect of albumin on the uptake of ligands of a wide range of membrane permeabilities was examined using the perfused rat liver. The results were similar to those expected from the UWL model: ligands with high membrane permeability (warfarin, diazepam and taurocholate) clearly exhibited albumin-mediated transport, those with medium membrane permeability (tolbutamide and salicylate) showed less albumin-mediated transport, and ligand with low membrane permeability (cefodizime) did not show albumin-mediated transport. These results were explained by simulation studies of two separate cases based on the UWL model; one assuming the rapid equilibrium of ligand binding with albumin, and the other considering the slow dissociation of ligands from albumin. In light of these findings, we suggest that the rate-limiting diffusion through the UWL plays an important role in the so-called albumin-mediated transport phenomenon.

Animals↗

PubMed1992

Kinetic analysis of hepatobiliary transport of vincristine in perfused rat liver. Possible roles of P-glycoprotein in biliary excretion of vincristine.

Recent studies using bile canalicular membrane vesicles have suggested that P-glycoprotein may play a role in excreting some anticancer drugs from the liver to the bile. At steady state after a continuous single-pass perfusion of a tracer concentration of [3H]vincristine in the rat liver, the extraction ratio was approximately 0.6, and 70% of the extracted drug was excreted into the bile mostly in unchanged form. The liver/perfusate and bile/liver unbound concentration ratios obtained after correction for intracellular binding and the inside-negative membrane potentials and/or pH difference between the inside and outside of the cells, were approximately 2-3 and 160-280, respectively, suggesting a highly concentrated biliary excretion process. We also examined the effects of verapamil, a P-glycoprotein-related transport inhibitor in cancer cells, on the hepatobiliary transport of [3H]vincristine. Verapamil 50 microM in the perfusate caused a decrease in the biliary excretion rate of [3H]vincristine, whereas [14C]taurocholate (reference compound) remained constant. In contrast, the hepatic uptake rate of [3H]vincristine exhibited minimum reduction, suggesting that verapamil selectively inhibited the biliary excretion of [3H]vincristine at the canalicular membrane. The fact that verapamil had little effect on the initial velocity of [3H]vincristine uptake by isolated hepatocytes also supports the above findings. Since the effect of 150 microM verapamil in the perfusate was not selective for vincristine, the biliary excretion rates of both compounds ([3H]vincristine, [14C]taurocholate) were reduced by this concentration of verapamil. In conclusion, the concentrative excretion of vincristine into the bile and its selective inhibition by a moderate concentration of verapamil provide indirect evidence for the contribution of P-glycoprotein to the biliary excretion of vincristine in a perfused rat liver system.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Physical and physiological specification of magnetic pulse stimuli that produce cortical damage in rats.

The effects of transcranial magnetic pulse stimuli on the brain tissue of rats were examined. In Experiment I, 52 male albino rats received pulsed magnetic stimulation of the head. Stimulus intensity, number of stimulations, stimulated sites, and interval between last stimulation and sacrifice for neuropathological examination were varied. High stimulus intensity (2.8 T) and 100 or more stimulations produced clearly defined microvacuolar changes in the neuropil portion of cortical layers 2-6 (especially layers 3 and 4) in 12 of 24 animals. Fewer stimulations and lower intensities produced no such effects in 28 rats given that stimulation. Midline stimulation and stimulation over the left hemisphere produced similar results. No other brain, ocular, or spinal structures manifested such changes. Lesions were present in animals that had intervals up to 30 days between the last stimulation and perfusion. In Experiment II with 18 animals, compound motor action potentials (CMAPs) evoked by magnetic stimulation of the cortical motor area and recorded from the right lower extremity were examined. The electromyographic threshold was 0.83 T. Further increases in stimulus intensity produced increases in CMAP amplitude, up to approximately 1.9 T. It was noted that the lesion-producing intensity (2.8 T) was 0.9 T greater than the intensity needed for near-asymptotic reactions and was 3.4 times the CMAP threshold value.

Animals↗

PubMed1992

Intra- and extracellular localization of hyaluronic acid and proteoglycan constituents (chondroitin sulfate, keratan sulfate, and protein core) in articular cartilage of rabbit tibia.

To demonstrate the intra- and extracellular localization of hyaluronic acid (HA) in articular cartilage of the rabbit tibia, biotinylated HA binding region, which specifically binds to the HA molecule, was applied to the tissue. In comparison with the localization of HA, that of chondroitin sulfate (CS), keratan sulfate (KS), and the protein core (PC) of the proteoglycan was examined by immunohistochemistry. Strong positive staining for HA was detected in chondrocytes located in the transition between the superficial and middle zones of the tissue. Pre-treatment with chondroitinase ABC, keratanase II, or trypsin enhanced the stainability for HA in peri- and intercellular matrices. Immunohistochemistry with or without enzymatic pre-treatment demonstrated that immunoreactivity for CS, KS, and PC was distinctly discerned in chondrocytes and in the extracellular matrix located in the middle and deep zones. In particular, the immunoreactivity for KS and PC was augmented by pre-treatment with chondroitinase ABC not only in chondrocytes but in the extracellular matrix located in the middle and deep zones. Microbiochemical analysis corresponded well with histochemical and immunohistochemical results. These results suggest that HA is abundantly synthesized and secreted in chondrocytes located in the transition between the superficial and middle zones.

Aggrecans↗

PubMed1992

Localization of hyaluronic acid, chondroitin sulfate, and CD44 in rabbit cornea.

To demonstrate the localization of hyaluronic acid (HA) in rabbit cornea, the biotinylated HA-binding region, which specifically binds to the HA molecule, was applied to the tissue. Localization of chondroitin sulfate (CS) and CD44, a possible cell surface receptor for HA, were also examined by immunohistochemistry. The stainability of HA changed depending on the fixatives used. Reaction products for HA were distinctly detected in epithelial cells and stromal keratocytes, but faintly in the extracellular matrix of the stroma when unfixed cryosections were applied. No positive reaction was found in the endothelium, except that the positive deposits formed a continuous layer on the apical surface of the endothelium. Electron microscopy using samples fixed with 2% paraformaldehyde revealed gold particles indicating HA labeling the intercellular space of the epithelium and stromal extracellular matrix. No intracellular deposition was detected in epithelial cells, whereas the gold labeling was seen in vacuolar structures of stromal keratocytes. Immunodeposits for CS were intensely localized in the epithelium and stroma, and weakly in the endothelium. Immunoreactivity for CD44 was found in the epithelial, endothelial and stromal cells. In particular, immuno-deposits for CD44 were detected in basal parts of epithelial cells, while they were localized in the apical surface of endothelial cells. These results suggest that HA is synthesized in and secreted from epithelial and stromal cells of rabbit cornea, while the localization of HA in the apical surface of the endothelium is closely associated with that of CD44. Moreover, the presence of CS in corneal tissue may play a role in its transparency, as has been suggested for keratan sulfate and dermatan sulfate.

Animals↗

PubMed1991

Clinical significance of the measurement of hepatic blood flow using xenon 133 and balloon catheter in patients undergoing treatment for hepatocellular carcinoma.

Total hepatic blood flow and portal blood flow were measured separately using a modified xenon 133 clearance method during angiography in 71 patients with chronic liver diseases, including 40 with proven hepatocellular carcinoma, and in 12 patients without detectable chronic liver injury who served as controls. Total hepatic and portal blood flow rates in controls were 805 +/- 149 ml/min and 667 +/- 206 ml/min, respectively. Total hepatic blood flow was significantly decreased in patients with compensated and decompensated liver cirrhosis (519 +/- 156 ml/min and 317 +/- 153 ml/min, respectively; P less than 0.01), as was portal blood flow (399 +/- 134 ml/min and 271 +/- 134 ml/min, respectively; P less than 0.01). Following transcatheter arterial embolization or hepatic resection (in 35 and 13 patients, respectively), hepatic failure occurred in 3 cases each. Embolization appeared contraindicated when hepatic portal blood flow was under 125 ml/min, and safe hepatic resection required an anticipated residual hepatic portal blood flow of at least 250 ml/min.

Carcinoma, Hepatocellular↗

PubMed1991

The effect of sodium hyaluronate on the migration of rabbit corneal epithelium. II. The effect of topical administration.

The effect of topically administered sodium hyaluronate (Na-HA) on the healing of corneal epithelial defect was investigated using rabbit eyes. The corneal epithelium was removed surgically or with iodine vapor or n-heptanol, and saline was administered to one eye as the control, and 0.1% or 0.25% Na-HA with a molecular weight of 87.3 x 10(4) to the other eye once daily. The area of epithelial defect was measured once daily before a topical administration, and the healing rate of epithelial defect was calculated. When the corneal epithelium was removed with iodine vapor, a topical administration of 0.1% or 0.25% Na-HA did not significantly accelerate the epithelial healing. But when removed surgically or with n-heptanol, the healing rates of the corneas treated with 0.25% Na-HA significantly exceeded those of the control eyes. When the epithelium was removed surgically, treatment with 0.1% Na-HA also significantly accelerated the healing. To determine why the effect of Na-HA differed in these three models with the epithelial defect, the amount of fibronectin (FN) produced by the cornea were investigated. The amount of FN produced was determined from the concentration of FN in the medium obtained after incubation of the corneo-scleral section with corneal epithelial defect, and the amount of Na-HA retained on that cornea was estimated from radioactivity detected in tears and cornea after a topical administration of 14C-labeled Na-HA (14C-Na-HA). The corneo-scleral section whose corneal epithelium had been removed surgically, or with n-heptanol, produced a significantly larger amount of FN than that whose corneal epithelium had been removed with iodine vapor. In addition, the amount of 14C-Na-HA retained on the cornea of the first or second model also significantly exceeded that on the cornea of the third model. The topical administration of Na-HA would thus appear to accelerate the healing of the epithelial defect producing a larger amount of FN or retaining a larger amount of Na-HA.

Administration, Topical↗

PubMed1991

Detection of in situ mitotic activity of dendritic epidermal T-cells by BrdU labeling.

We analyzed mitotic dendritic epidermal T-cells (DETC) in the epidermis of C3H/He (Thy-1.2+) mice, using double immunoenzymatic labeling. Ear skin was incubated with 100 microM bromodeoxyuridine (BrdU) for 5 hr and then either directly studied or cultured for an additional 12 hr in BrdU-free medium. After BrdU labeling, with or without additional culture, epidermal sheets were obtained by ethylenediaminetetraacetic acid separation. The epidermal specimens were immunostained by the peroxidase method to visualize nuclear BrdU and then by the biotin-streptavidin-alkaline phosphatase method for surface Thy-1.2 antigen. In specimens processed immediately after BrdU labeling, a mean 3.0% of all basal cells were labeled with BrdU and a mean 1.1% of the BrdU-labeled cells were also positive for Thy-1.2. Moreover, a mean 2.1% of the DETC had incorporated BrdU. BrdU-labeled DETC had a variety of appearances; they were dendritic and round in the BrdU-treated specimens, while oval and paired cells were also found in the specimens after additional culture. These morphological changes of BrdU-labeled DETC demonstrate that resident DETC can become mother cells undergoing mitosis through the retraction of their dendrites, and it appears that DETC divide at a relatively high rate, i.e., up to 10% of the DETC may enter the S-phase of the cell cycle every 24 hr.

Animals↗

PubMed1990

Kinetic analysis of the dose-dependent hepatic handling of 1-anilino-8-naphthalene sulfonate in rats.

The dose dependency in the hepatic transport of an anionic fluorescent dye, 1-anilino-8-naphthalene sulfonate (ANS), was investigated by measuring the plasma disappearance and biliary excretion in rats. Bulk of the administered ANS distributed into the liver at 10 min after iv bolus injection. The plasma disappearance curves of ANS were then kinetically analyzed based on a two-compartment model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). The total body clearance (CLtot) decreased with increasing dose of ANS. That is, the values of CLtot were 4.06 and 1.98 ml/min/per kg at the doses of 3 and 100 mumol/kg, respectively. The clearances of the uptake and sequestration processes (CLup and CLseq, respectively) for a total ligand were constant irrespective of dose, while the efflux clearance (CLeff) for a total ligand was increased by twofold with increasing dose. A mechanism for the increase in the CLeff value might be explained by a saturation of the ANS binding to the intracellular proteins. The hepatocellular distribution and the binding of ANS to cytosolic proteins were then determined. ANS mainly distributed to the cytosol fraction, and the unbound fraction in the cytosol increased from approximately 0.04 to 0.09 when the cytosolic concentrations of ANS increased from 40 to 900 microM, respectively. In spite of such increase in the unbound fraction in the cytosol, the CLseq values remained unchanged with increasing dose, suggesting that the saturation of sequestration clearance for unbound ANS might occur. Furthermore, the plasma disappearance curves of ANS at various doses were simultaneously analyzed based on three nonlinear kinetic models: Model I is a model incorporating both saturable intracellular binding and saturable sequestration; Model II is a model incorporating only saturable intracellular binding; Model III is the model incorporating only saturable sequestration. Goodness-of-fit evaluated by AIC value was best for Model I. Taken together, the nonlinearity in the plasma clearance of ANS was confirmed to be attributed to saturation of both its binding to cytosolic proteins and sequestration process.

Anilino Naphthalenesulfonates↗

PubMed1990

Evoked potentials during REM sleep reflect dreaming.

Polygraphic recordings were collected for 11 normal subjects during sleep and wakefulness in order to investigate characteristics of the rapid eye movement (REM) associated potentials. EEGs were averaged using 5 different triggering points: (1) saccade onset under the normal ambient illumination, (2) saccade onset in the total darkness, (3) onset of REMs during REM sleep, (4) flash during REM sleep, and (5) flash during stage 2 sleep. In the central area, positive potentials appeared with waking saccades under the normal ambient illumination (P240L) and REMs (P185R). The latency of P185R associated with REMs was significantly shorter than that of P240L associated with waking saccades. These findings suggest that P185R is evoked by PGO waves occurring just before the REM. A small positive potential appeared in the occipital area with waking saccade under the normal ambient illumination (P260L) and REMs in the total darkness (P250R). Conspicuous absence of these waves for waking saccades in the total darkness suggests that P250R accompanied with REMs reflects activities involved with the cognitive processes occurring when a subject scans a dream image during REM sleep.

Adult↗

PubMed1990

Effect of various organic anions on the plasma disappearance of 1-anilino-8-naphthalene sulfonate.

The effects of various organic anions on the hepatic transport of an anionic fluorescent dye, 1-anilino-8-naphthalene sulfonate (ANS) were investigated by measuring the plasma disappearance-time profiles in rats. Ten min after the i.v. administration of ANS (3 mumol/kg), various organic anions (60 mumol/kg) were injected in a bolus. Sulfobromophthalein (BSP), bromophenol blue (BPB) and rose bengal (RB) induced a transient increase in the plasma concentration of ANS (the so-called 'counter-transport' phenomena). The effect of rose bengal was somewhat different. After the administration of rose bengal, the plasma concentration of ANS decreased rapidly followed by a gradual increase. On the other hand, after the administration of bilirubin and taurocholate, the transient increases in plasma ANS concentrations were minimal. No effect was observed after the administration of phenolsulfophthalein (PSP) or oleate. The effects of these organic anions on the binding of ANS to rat liver cytosols were examined by equilibrium dialysis. Sulfobromophthalein, bromophenol blue and rose bengal, which yielded an in vivo 'counter-transport' phenomena, markedly inhibited ANS binding to cytosolic proteins. On the other hand, the other organic anions examined had very small, if any, inhibitory effect. The ANS binders in the cytosol were then identified by gel filtration. ANS bound mainly to X and Y (ligandin) fractions in the cytosol. Sulfobromophthalein, which is one of the organic anions exhibiting the in vivo 'counter-transport' phenomenon, remarkably inhibited ANS binding to ligandin fraction. It was thus suggested that the in vivo 'counter-transport' phenomena may be also explained by the enhancement of back diffusion due to the displacement of intracellular binding. In conclusion, one should be more cautious in interpreting data obtained from so-called in vivo 'counter-transport' experiments.

Anilino Naphthalenesulfonates↗

PubMed1990

The effect of sodium hyaluronate on the migration of rabbit corneal epithelium. I. An in vitro study.

The effect of sodium hyaluronate (Na-HA) on the migration of corneal epithelium was investigated in vitro using corneo-scleral sections of rabbits. The effect on migration was evaluated by the length of migrating epithelium on the cut surface of corneal stroma after incubation in media containing Na-HA of various molecular weights or concentrations. The medium concentration of Na-HA was 400 micrograms/ml, and the molecular weights were 0.4 x 10(4), 2 x 10(4), 10 x 10(4), 68 x 10(4), 102 x 10(4) and 216 x 10(4). Regarding Na-HA with a molecular weight of 102 x 10(4); media containing Na-HA at concentrations of 50, 100, 200, 400, 800, 2000 and 4000 micrograms/ml were also investigated. When the concentration of Na-HA was 400 micrograms/ml, Na-HA with molecular weights of over 68 x 10(4) accelerated significantly the epithelial migration. Regarding Na-HA with a molecular weight of 102 x 10(4), acceleration was observed at concentrations of 200, 400 and 800 micrograms/ml. Furthermore, the concentration of fibronectin (FN) in medium containing the effective Na-HA was significantly lower than that in the control medium after the incubation. These results suggest a possibility that the accelerative effect of Na-HA depends on the reduction of FN release from the cornea or the facilitation of FN deposition on the cornea.

Animals↗

PubMed1990

The innermost cell layer of the outer root sheath is positive with Ki-67.

The expression of a cell proliferation-associated human nuclear antigen was immunohistochemically studied in human anagen hair and hair follicles using the monoclonal antibody Ki-67. The reaction of Ki-67 in mature anagen hair follicles was observed in the hair matrix cells and outer root sheath (ORS) cells. Nuclear staining was seen in a small number of matrix cells and in some ORS cells; this finding corresponded to the thymidine or bromodeoxyuridine labeling studies previously reported. In addition, there were two different patterns of cytoplasmic staining in the ORS: strong staining of the innermost cells (IMC) and weaker staining of the other ORS cells in the isthmus. Ki-67 reactivity of the IMC layer was observed at each stage of anagen and was regularly seen from the upper bulb to the isthmus. Ki-67 is a commercially available antibody that detects cycling cells. However, the IMCs in anagen hair follicles showed cytoplasmic labeling by Ki-67 from the matrix cells in the upper bulb to the distal portion of the isthmus.

Adolescent↗

PubMed1990

[Evaluation of mica crystal glass ceramic crown marginal fitness].

The purpose of this study is to investigate the influence of three marginal shape of abutment teeth (Flat, Moderate and Steep) on the fitness of castable glass ceramics (DICOR) crown clinically. The following results were obtained: 1. The change of width of three marginal shapes showed the same tendency on each firing procedure. 2. The vertical change of three marginal shapes showed the most constant on Flat and decreased on Steep. 3. On the marginal edge, the Labiopalatal gaps were larger than Mesiodistal gaps. 4. On Labiopalatal section, the gaps of Steep were larger than those of Flat and Moderate especially as cast. 5. The gaps Flat were almost same on Labial, Palatal, Mesial and Distal parts.

Aluminum Silicates↗