• YAKHAK HOEJI
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• v.40 no.6
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• pp.705-712
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• 1996

We have previously shown that determination of glucose uptake using ${\alpha}$-methylglucose(${\alpha}$-MG) is very sensitive and rapid parameter for the assessment of loss of cellular fu nction in renal cell line($LLC-PK_1$). The present study was designed to elucidate the mechanism of inhibition of ${\alpha}$-MG uptake and the intracellular site of toxic action of cisplatin(CIS). $LLC-PK_1$ cells were exposed to various concentrations(5 ${\mu}$M-l00 ${\mu}$M) of CIS for 5 hrs or 24 hrs and ${\alpha}$-MG uptake was determined. Mitochondrial function was evaluated by measuring intracellular ATP content and MTT reduction. The activities of marker enzymes for the basolateral membrane(Na$^+$-K$^+$ ATPase) and brush border membrane (alkaline phosphatase: ALP) were also measured. CIS treatment significantly inhibited the ${\alpha}$-MG uptake in a time- and dose-dependent manner above 25 ${\mu}$M for 5 hrs. Intracellular ATP content and MTT reduction were affected by 24 hr-treatment of 50 ${\mu}$M CIS. The activities of Na$^+$-K$^+$ ATPase and ALP were significantly decreased at 10 ${\mu}$M and 5 ${\mu}$M of CIS for 24 hrs, respectively. The incubation with CIS for 5 hrs had no effects on the intracellular ATP content, MTT reduction and the activities of marker enzymes up to 100 ${\mu}$M. These results partly indicate that inhibition of ${\alpha}$-MG uptake by CIS may not be attributed to the disturbance of mitochondrial function or inhibition of the activity of Na$^+$-K$^+$ ATPase and can be resulted from direct effect of CIS on the Na$^+$/glucose cotransporter in brush border membrane. This study shows that additional mechanistic information, indicating the intracellular site of nephrotoxic action, can be gained by coupling the ${\alpha}$-MG uptake and ATP content or the activity of Na$^+$-K$^+$ ATPase.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.219-227
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• 2008

Bacillus thuringiensis was isolated as a pathogen of the sotto disease of silkmoth larvae about a hundred years ago. Since then, this bacterium has attracted attentions of not only insect pathologists but also many other scientists who are interested in its strong and specific insecticidal activity. This has led to the recent worldwide development of B. thuringiensis-based microbial insecticides and insect-resistant transgenic plants, as well as a landmark discovery of par asp orin, a cancer cell-specific cytotoxin produced by B. thuringiensis. In this review, we describe examination of interaction between inclusion proteins of B. thuringiensis and brush border membrane of insects using a surface plasmon resonance-based biosensor, identification and characterization of parasporin-4, the latest parasporin produced by the B. thuringiensis A1470 strain, and an effective method for preparing the parasporin-4 from inclusion bodies expressed in the recombinant Escherichia coli cells.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.1
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• pp.41-46
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• 2002

Effect of cadmium (Cd) intoxication on renal acid-base regulation was studied in adult male Sprague-Dawley rats. Cd intoxication was induced by subcutaneous injections of $CdCl_2$ at a dose of 2 mg Cd/kg/day for $3{\sim}4$ weeks. In Cd-intoxicated animals, arterial pH, $PCO_2$ and plasma bicarbonate concentration decreased, showing a metabolic acidosis. Urine pH and urinary bicarbonate excretion increased and titratable acid excretion decreased with no change in ammonium excretion. In renal cortical brush-border membrane vesicles derived from Cd-exposed animals, the $Na^+/H^+$ antiporter activity was significantly attenuated. These results indicate that chronic exposures to Cd impair the proximal tubular mechanism for $H^+$ secretion (i.e., $Na^+/H^+$ antiport), leading to a metabolic acidosis.

• Applied Microscopy
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• v.17 no.1
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• pp.115-130
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• 1987

The present experiment was performed to investigate the acute effects of cadmium on ultrastructural and biochemical changes in mouse kidney and compare these changes with liver damage. Mouse were injected with cadmium chloride at a dose of 5 mg/kg body weight. After treatment, mouse were sacrificed at time intervals of 6, 12, 24 and 48 hours. It was observed that ultrastructural changes in mouse kidney were composed of swelling of mitochondria, dilation in endoplasmic reticulum, wrinkling at basal infolded membrane, formation of autophagosome and partial loss of microvilli in brush. border, and that ultrastructural changes in liver were mitochondrial change, dilation and deterioration of rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum. Biochemical effects of cadmium were more severe on liver than kidney. Therefore, acutely injected cadmium caused not only liver damage, but also kidney damage.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1457-1465
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• 2012

Intestinal phosphate (Pi) absorption across the apical membrane of small intestinal epithelial cells is mainly mediated by the type IIb Na-coupled phosphate co-transporter (NaPi-IIb), but its expression and regulation in the chicken remain unclear. In the present study, we investigated the mRNA and protein levels of NaPi-IIb in three regions of chicken small intestine, and related their expression levels to the rate of net phosphate absorption. Our results showed that maximal phosphate absorption occurs in the jejunum, however the highest expression levels of NaPi-IIb mRNA and protein occurs in the duodenum. In response to a low-Pi diet (TP 0.2%), there is an adaptive response restricted to the duodenum, with increased brush border membrane (BBM) Na-Pi transport activity and NaPi-IIb protein and mRNA abundance. However, when switched from a low-(TP 0.2%) to a normal diet (TP 0.6%) for 4 h, there is an increase in BBM NaPi-IIb protein abundance in the jejunum, but no changes in BBM NaPi-IIb mRNA. Therefore, our study indicates that Na-Pi transport activity and NaPi-IIb protein expression are differentially regulated in the duodenum vs the jejunum in the chicken.

• Parasites, Hosts and Diseases
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• v.31 no.1
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• pp.13-20
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• 1993

The histological change of the billary mucosa in clonorchiasis is characterized as adenomatous hyperplasia, and cross-sectioned mucosa looks like intestinal mucosa. In addition to the glandular hyperplasla, the metaplasia of mucin secreting cells is also known. The present study investigated the presence of intestinal secretion from the biliary mucosal cells of rabbits and rats with Clonorchis sinensis infection. The rabbit was infected with 300 and the rat was infected with 100 metacercariae of C. sinensif. A part of the animals were followed up after praziquantel treatment. The rabbit livers were prepared for histochemistry to observe any endocrine secretion and the bile duct mucosa of the mice was processed far the activity of brush border membrane (BBM)-bound enzymes of the small intestine. Immunohistochemistry with the polyclonal antibodies and biotin-streptavidin-peroxidase staining kit showed no positive cells for gastrin and secretin, but a few cells were positive for serotonin. The proliferated billiw mucosa of the mice revealed no activity of dissaccharidases and aminopeptidase. Only alkaline phosphatase activity was found both in the control and the infected. The hyperplastic billary mucosal cells showed no gastrointestinal secretory functions. The serotonin secreting cells may be one of the inflammatory cells.

• The Korean Journal of Physiology
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• v.25 no.1
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• pp.49-60
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• 1991

The change of the acridine orange absorbance was used to monitor the formation and/or dissipation of a pH gradient in microvillous membrane vesicles (MVV) isolated from human term placenta. Under $Na^+$ efflux conditions, an acidification of the intravesicular space occured and it was completely inhibited by 0.1 mM amiloride. Under $K^+$ efflux conditions, an acidification of the intravesicular space occured and it was potentiated by valinomycin or FCCP. An inwardly directed chloride gradient also induced a minor intravesicular acidification, but it was not observed in voltage-clampled MVV. The initial rate of the dissipation of a pH gradient was accelerated by pulse injections of $Na^+$ in a saturable manner and $Li^+$ could replace $Na^+$. The kinetic parameter of $Na^+$ in placental $Na^+/H^+$ exchange was similar to that of renal $Na^+/H^+$ exchange. Amiloride was a inhibitor of directly coupled $Na^+/H^+$ exchange and its $IC_{50}$ in placental MVV was about 14-fold higher than that in renal brush border membrane. These results indicate that $Na^+/H^+$ exchanger exists in human placental MVV and that its kinetic characteristics is similar to that of renal $Na^+/H^+$ exchanger but its pharmacological characteristics is different. In placental MVV $K^+,\;H^+$, and, relatively minor chloride conductances are present. The magnitude of $Cl^-/OH^-$ exchange, even though it exists, seems to be smaller than that of $Na^+/H^+$ exchange.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.203-214
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• 1994

Using the methods of stopped-flow and epifluorescence microscopy with entrapped fluorophore, membrane permeability of $NH_3$ and weak acids in liposomes, renal brush border (BBMV) and basolateral membrane vesicles (BLMV), and primary culture cells from renal proximal tubule was measured. Permeability coefficient (cm/sec) of $NH_3$ was $(2.9{\times}10^{-2}$ in phosphatidylcholine liposome $25^{\circ}C)$, $5.9{\times}10^{-2}$ in renal proximal tubule cell $(37^{\circ}C)$, $4.0{\times}10^{-2}\;and\;2.4{\times}10^{-2}$ in BBMV and BLMV $(25^{\circ}C)$, respectively. Formic acid has the highest permeability coefficient among the weak acids tested, which was $4.9{\times}10^{-3}$ in liposome, $5.0{\times}10^{-3}$ in renal proximal tubule cell, $9.1{\times}10^{-3}$ in BBMV and $3.8{\times}10^{-3}$ in BLMV. There was a linear relationship between external concentration of nonionized formic acid and initial rate of flux of formic acid in liposome, and the slope coincided with the value of permeability coefficient of formic acid measured in pH 7.0. These results show that techniques of stopped-flow and epifluorescence microscopy with entrapped fluorophore provide the precise method of measurement of very rapid transport of nonelectrolytes through membranes with the advantages of instantaneous mixing effect, good resolution time and easy manipulation.

• Journal of Acupuncture Research
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• v.18 no.2
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• pp.111-122
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• 2001

Objectives ; This study was undertaken to determine if Salviae Radix herb-acupuncture (SRA) exerts protective effect against alterations in membrane transport function in rabbits with mercury chloride (Hg)-induced acute renal failure. Methods and Results ; The administration of Hg at a subcutaneous single dose of 10mg/kg caused a reduction in GFR to 9.4% of the basal value and an increase in fractional Na+ excretion to 10-fold, indicating generation of acute renal failure. When animals were acupunctured with $0.5m{\ell}$ of SRA extract (0.1%) in both sides of Shinsu(BL23) for 7 days prod to Hg administration, such changes were significantly attenuated. The fractional excretion of glucose and phosphate was increased to approximately 132-fold and 7-fold, respectively, in rabbits treated with Hg alone, but the fractional excretion of glucose was increased to 26-fold and that of phosphate was not different from the basal value in SRA-pretreated rabbits. Uptakes of glucose and phosphate in purified isolated brush-border membrane and $Na^+-K^+$-ATPase activity in microsomal fraction were inhibited in rabbits treated with Hg alone, suggesting that impairment in proximal reabsorption of glucose and phosphate is resulted from a direct damage of membrane transport carriers and disruption of the normal $Na^+$ gradient. Conclusions ; Such changes were prevented by SRA. Uptakes of organic ions, PAH and TEA, in renal cortical slices were inhibited by the administration of Hg, which was prevented by SRA. Pretreatment of an antioxidant DPPD attenuated the increase in the fractional excretion of glucose and phosphate induced by the administration of Hg.

• Preventive Nutrition and Food Science
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• v.16 no.2
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• pp.135-141
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• 2011

Inhibition of intestinal glucose uptake is beneficial in reducing the blood glucose level for diabetes. To search for an effective intestinal glucose uptake inhibitor from natural sources, 70 native edible plants, fruits and vegetables were screened using Caco-2 cells and fluorescent D-glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG). A compound that was able to inhibit glucose uptake was isolated from methanol extract of Punica granatum L. and called PG-1a. PG-1a appears to be a phthalic acid-diisononyl ester- like compound (PDE) with molecular weight of 418. The inhibitory effect of PG-1a on intestinal glucose uptake was dose-dependent with 89% inhibition at $100\;{\mu}g$/mL. Furthermore, the intestinal glucose uptake inhibitory effect of PG-1a was 1.2-fold higher than phlorizin, a well known glucose uptake inhibitor. This study suggests that PG-1a could play a role in controlling the dietary glucose absorption, and that PG-1a can effectively improve the diabetic condition, and may be used as an optional therapeutic and preventive agent.