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Biomedical subjects

M Fujikawa

Publications and source records attributed to M Fujikawa.

At least 55 records · Page 3Linked to original sources
PubMed1995

Characterization of LLC-PK1 kidney epithelial cells as an in vitro model for studying renal tubular reabsorption of protein drugs.

PURPOSE: The purpose of this study was to assess whether LLC-PK1 renal epithelial cells could serve as an in vitro model for studying the renal tubular reabsorption of protein drugs. METHODS: The association of 111In-labeled model protein drugs, bovine serum albumin (BSA), superoxide dismutase (SOD), soybean trypsin inhibitor (STI), and [Asu1.7]-eel calcitonin (Asu-ECT), with the monolayers of LLC-PK1 renal epithelial cells was characterized under various conditions. RESULTS: The cellular association of these proteins was temperature-dependent and varied according to the protein. Saturation kinetics were observed for STI association, with the apparent Km and Vmax values determined to be 66.3 micrograms/ml and 250 ng/mg protein/min, respectively. The association of STI decreased with increases in medium pH from 5.4 to 8.4 and was inhibited significantly by 2,4-dinitrophenol, sodium azide, cytochalasin B, and colchicine, suggesting that the cellular association involved endocytosis. Mutual inhibition was observed in competitive binding experiments with the four protein drugs, suggesting that they shared a common binding site on the luminal membrane of LLC-PK1 cells. Taken together, these findings show that a variety of protein drugs bind to LLC-PK1 cells in a non-specific manner and possibly undergo endocytosis, a phenomenon that is similar to in vivo proximal tubular reabsorption. CONCLUSIONS: LLC-PK1 renal epithelial cells would be a suitable model system for the study of the renal proximal tubular reabsorption of protein drugs.

Absorption↗
PubMed1994

Novel theta class glutathione S-transferases Yrs-Yrs' and Yrs'-Yrs' in rat liver cytosol: their potent activity toward 5-sulfoxymethylchrysene, a reactive metabolite of the carcinogen 5-hydroxymethylchrysene.

Two novel theta class glutathione S-transferases (GSTs), designated Yrs-Yrs' and Yrs'-Yrs', were isolated from rat liver cytosol and purified to homogeneity. Polyclonal antibody raised against the previously reported theta class GST Yrs-Yrs (Hiratsuka, A. et al., J. Biol. Chem. 265, 11973 (1990)) cross-reacted with GSTs Yrs-Yrs' and Yrs'-Yrs'. These three theta class GSTs had different pI values and were separated by chromatofocusing. The enzyme subunit Yrs' was separated from Yrs by reverse partition HPLC, but identical to Yrs in the first 37 N-terminal amino acid sequence. Like GST Yrs-Yrs, both GSTs Yrs-Yrs' and Yrs'-Yrs' were not retained on an S-hexyl-GSH affinity column and had little activity toward 1-chloro-2,4-dinitrobenzene. However, they showed potent activities toward the reactive sulfate ester of the carcinogen, 5-hydroxymethylchrysene. GSTs Yrs-Yrs and Yrs'-Yrs' showed much higher GSH peroxidase activities toward arachidonate hydroperoxide than did rat liver alpha class GST Ya-Ya.

Amino Acid Sequence↗
PubMed1994

Changes in biliary glutathione level during ischemia-reperfusion of rat liver.

Changes in hepatic and biliary glutathione levels were studied in rat liver treated with tert-butyl hydroperoxide (t-BuOOH) and subjected to ischemia-reperfusion. Immediately after t-BuOOH administration, the oxidized glutathione (GSSG) values and reduced glutathione (GSSG/GSH) ratio in the bile increased dose-dependently and then returned to control level within 10 min, whereas the hepatic ATP level and bile flow rate were not affected by t-BuOOH at doses of up to 1.0 mmol/kg. These data suggested that the liver remains viable on treatment with up to 1.0 mmole/kg t-BuOOH, and that hepatocytes can rapidly dismute t-BuOOH at up to this dose. The hepatic GSH and GSSG levels did not vary appreciably during ischemia for 10 or 30 min or during subsequent reperfusion, but the GSSG/GSH ratio increased after ischemia for 30 min. The rate of bile flow and the biliary level of GSH decreased after ischemia for 30 min in proportion to the decrease in the hepatic ATP level. However, the biliary GSSG concentration did not vary on reperfusion, although GSSG secretion into the bile is also related to the hepatic ATP level. As a result, the GSSG/GSH ratio in the bile increased during reperfusion after ischemia for 30 min. This increased ratio is thought to reflect oxidation of hepatic GSH by hydroperoxide produced during reperfusion. The GSSG/GSH ratio in the bile after 30 min ischemia corresponded to that observed after a small dose (0.07 mmole/kg body wt) of t-BuOOH, which hepatocytes could dismute rapidly without loss of their viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1994

A rare portosystemic shunt detected by MRI and diagnosed by dynamic liver scintigraphy with Tc-99m phytate.

Although various types of portosystemic shunts with portal hypertension have been widely reported, a collateral circulation near the pancreas head is rare. The authors report a case of a rare portosystemic shunt surrounding the pancreatic head, which was diagnosed by dynamic liver scintigraphy using Ikoma's scintigraphic criteria for the presence of portosystemic shunts. According to these criteria, abnormal accumulation of radioactivity at various abdominal sites (not identified on static images after the dynamic study) on 6 or more continuous frames of 5-second intervals (i.e., for 30 seconds or more after the arterial phase) indicates the presence of a portosystemic shunt. If liver scintigraphy is performed on a patient with portal hypertension, the dynamic study is valuable in the detection and diagnosis of a portosystemic shunt.

Aged↗
PubMed1994

Effect of eicosapentaenoic acid ethyl ester on albuminuria in streptozotocin-induced diabetic rats.

Wistar rats (4-week-old) were administered with streptozotocin (45 mg/kg) through tail veins. After 3 months, diabetic rats were divided into 2 groups. One group (EPA group, n = 16) was fed a lipid-free diet (90%, w/w) plus lard (8%) and 90% pure eicosapentaenoic acid ethyl ester (2%) for 6 months. The other group (control group, n = 16) was fed in the same way except that eicosapentaenoic acid ethyl ester was replaced by safflower oil. Twenty-four-hour urine was collected just before starting the experimental diets and during the 6-month experimental period at monthly intervals. There were no differences in food intake and body weight between the two groups throughout the experiment. The mean microalbuminuria of the EPA group became significantly lower than that of the control group after 4 months on the diets through the end of the study (6 months). The mean microalbuminuria levels at the end of the study were 1.38 mg/day in the EPA group (n = 9) and 5.19 mg/day in the control group (n = 6) (p < 0.01). Eicosapentaenoic acid administration might retard the progression of diabetic nephropathy by reducing microalbuminuria.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

[Rapid growth of eyelid squamous cell carcinoma in elderly patients with multiple cancers].

Two cases of squamous cell carcinoma of the eyelid are reported. Both patients had multiple cancers. Case 1 was an 81-year-old man who had a squamous cell carcinoma on his right upper eyelid and on his right palm, and Bowen's disease in his left thumb. Case 2 was an 87-year-old woman who had a squamous cell carcinoma on her right lower eyelid, an adenocarcinoma in her colon, and a uterus cancer of unknown histology. In spite of their advanced age, the eyelid tumors showed rapid growth in both cases. The reason for this rapid growth was unclear. However, the presence of cancers in other organs may provide clues, because the immunological ability in patients with multiple cancers is considered to be weakened.

Adenocarcinoma↗
PubMed1993

Disposition characteristics of protein drugs in the perfused rat kidney.

The renal disposition characteristics of 111In-labeled neocarzinostatin (NCS), soybean trypsin inhibitor (STI), and superoxide dismutase (SOD) were studied in the perfused rat kidney. In a single-pass indicator dilution experiment, venous and urinary recovery profiles and tissue accumulation of proteins were determined under filtering or nonfiltering conditions. In the nonfiltering kidney perfusion experiment, no significant tissue accumulation was observed, suggesting minimal uptake from the glomerular and peritubular capillary sides. Therefore, tissue recovery corresponded to that with tubular reabsorption after glomerular filtration. The total amount of NCS or STI being filtrated through glomeruli, the sum of tissue and urinary recoveries, was similar to that of inulin, but that of SOD was about half. Similarly, the steady-state distribution volumes (Vd) of NCS and STI obtained by moment analysis of their venous outflow curves were similar to that of inulin, while the Vd value of SOD was significantly lower. These results suggest the restricted passage of SOD through the glomerular and postglomerular capillary wall. The tubular reabsorption ratio of proteins against the total filtrated amount decreased with an increase in the administered dose, suggesting nonlinearity of reabsorption. SOD had the largest reabsorption ratio. Thus, this experimental system is useful for quantitative analysis of renal disposition of proteins.

Animals↗
PubMed1992

Comparison of the conversion rates of alpha-linolenic acid (18:3(n - 3)) and stearidonic acid (18:4(n - 3)) to longer polyunsaturated fatty acids in rats.

The delta 6-desaturase reaction is regarded to be the rate-limiting step in the conversion of linoleic acid (18:2(n - 6)) to arachidonic acid (20:4(n - 6)). The same is probably also the case with the conversion of alpha-linolenic acid (18:3(n - 3)) to eicosapentaenoic acid (20:5(n - 3)). However, there are very few in vivo studies that directly compared the conversion rate between 18:3(n - 3) and stearidonic acid (18:4(n - 3)), which is the delta 6-desaturated product of 18:3(n - 3). We compared this rate by feeding rats on a lipid-free diet supplemented with lard (9%, w/w) and 18:3(n - 3) ethyl ester (1%) diet or on a diet containing lard (9%) and 18:4(n - 3) ethyl ester (1%). A lard (10%)-supplemented diet was used as the control diet. The fatty acid compositions of total phospholipids, triglycerides and free fatty acids of both liver and plasma were measured after 1 or 3 weeks on different diets. The molar ratio of 20:5(n - 3) of most lipid fractions was about 2-fold higher in rats fed the 18:4(n - 3)-supplemented diet than in rats fed the 18:3(n - 3)-supplemented diet. 18:4(n - 3) was found in the liver lipid fraction in only a very small amount, even in the 18:4(n - 3)-supplemented groups. Thus, desaturation at C-6 is suggested to be the rate-limiting step in the conversion of 18:3(n - 3) to 20:5(n - 3).

Animals↗
PubMed1992

Restoration of the mandible by full-thickness calvarial bone flap.

Two patients with reconstruction of a massive mandibular defect with vascularized full-thickness calvarial bone flaps are reported. In Patient 1, the mandibular body developed osteomyelitis and once was replaced with a metallic prosthesis. The prosthesis later perforated the skin and was removed. Full-thickness calvarial bone flaps were elevated bilaterally to reconstruct the mandibular body. In Patient 2, the mandible was totally destroyed by invasion of squamous cell carcinoma. The lower one-half of the face was resected and replaced with a large island scalp flap with full-thickness calvarial bone.

Adult↗
PubMed1992

Eicosapentaenoic acid inhibits antigen-presenting cell function of murine splenocytes.

Recently, many investigators have studied the effects of eicosapentaenoic acid (EPA)-rich fish oil on immune function and immune disease. However, effects of dietary supplementation of fish oil or EPA on the immune system are still unclear. In the present study, the effects of EPA on antigen presentation were investigated. We have used antigen-specific helper T-cell clones that proliferate in the presence of antigen [keyhole limpet haemocyanin (KLH)] and spleen cells as antigen-presenting cells (APC). Mice were divided into two groups and fed an experimental diet or a control diet for 4 weeks ad libitum. In mice fed the experimental diet, the arachidonic acid (AA) content of spleen cells was decreased and that of EPA and docosapentaenoic acid was increased markedly compared to those of the control diet. Dietary enrichment with EPA inhibited the ability of accessory cells to present antigen to murine helper T-cell clones. This effect was observed for two distinct helper T-cell clones, Th1 and Th2. We also examined the effects of EPA-TG emulsion on APC function. The direct addition of EPA-TG emulsion to a T-cell proliferation assay system suppressed APC function. The inhibition was proportional to the concentration of EPA-TG emulsion. Pretreatment of splenocytes with EPA-TG emulsion resulted in inhibition of APC function. Inhibition of antigen presentation by dietary supplementation with EPA might depress immune reactivity.

Animals↗
PubMed1990

Enhancement of depressed lymphokine activated killer cell activity in patients with hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) patients can be divided into two groups according to the degree of lymphokine activated killer (LAK) cell activity; a high LAK activity group (H-LAK-HCC) and a low LAK activity group (L-LAK-HCC). Interferon-gamma (IFN-gamma) production is severely defective in L-LAK-HCC but not defective in H-LAH-HCC. IFN-gamma production is suppressed with the addition of anti-Tac in dose dependent manner, though LAK activity is suppressed only in the presence of high concentration of anti-Tac. LAK activity is suppressed with the addition of anti-IFN-gamma, which is most prominent when the antibody is present during the first 12 hr of incubation. LAK generation is enhanced with the addition of recombinant IFN-gamma, which is most prominent when it is present during the first 12 hr of incubation. However, this enhancing effect is less prominent in L-LAK-HCC as compared to normals, liver cirrhosis, and H-LAK-HCC. This enhancement is regarded to depend on the presence of Leu7+ and Leu11+ subset, as this enhancement is abandoned and IFN-gamma production is inhibited when either of these subsets is deleted. These data suggest that IFN-gamma production and the participation of Leu7+ and Leu11+ subsets is important in sufficient LAK generation, and that poor IFN-gamma production and insufficient response to IFN-gamma may be the cause of severely defective LAK generation in L-LAK-HCC.

Aged↗
PubMed1990

Staged, laminated, costal cartilage framework for ear reconstruction.

Two features of greatest importance in achieving a normal appearance in the reconstruction of an ear with microtia are that a conchal component with sufficient size, shape, and depth is present; and that auricular projection, sufficient in degree to show contours that appear normal from a posterior view, is present. The authors describe the construction of a staged, laminated framework that helps achieve these goals.

Ear Cartilage↗
PubMed1989

Different patterns of leakage of cytosolic and mitochondrial enzymes.

The mechanisms of leakage of intracellular enzymes, and especially the cytosolic and mitochondrial isozymes of aspartate aminotransferase (AST), in ischemic rat liver were studied. On recirculation of ischemic liver, cytosolic AST (cAST) promptly appeared in the blood. Release of cytosolic enzymes, including cAST and lactic dehydrogenase, resulted from disruption of blebs that protruded from parenchymal cells into the sinusoidal space. When these blebs were formed in ischemic liver, mitochondria still remained in core regions of the injured cells and were not found in the blebs. Consistent with this fact, mitochondrial AST (mAST) did not leak into the circulation from ischemic liver until most of the cAST had leaked out. This delayed leakage of mitochondrial enzymes was also consistent with the fact that the mitochondrial membranes maintained a diffusion barrier against matrix enzymes even after anoxia for 2 h, when their oxidative phosphorylation capacity had been lost. These results indicate that mitochondrial enzymes are liberated into the blood only after appreciable disintegration of the cells, probably necrosis, and that the cumulative activity of mAST in the blood should reflect the extent of necrosis in ischemic organs better than that of cAST.

Animals↗
PubMed1989

Adoptive immunotherapy with lymphokine-activated killer cells plus recombinant interleukin 2 in patients with unresectable hepatocellular carcinoma.

Ten patients with hepatocellular carcinoma, three of whom had pulmonary metastasis, were treated with adoptive immunotherapy using autologous lymphokine-activated killer cells plus recombinant interleukin 2. Patients received 15 micrograms per day of recombinant interleukin 2 consecutively (for 14 to 64 days), from Day 7 prior to the first leukapheresis, and received 10(9) to 10(10) lymphokine-activated killer cells once or twice per week intravenously; the lymphokine-activated killer cells had been generated from mononuclear cells obtained through leukapheresis. Preadministration of recombinant interleukin 2 prior to the first leukapheresis resulted in a remarkable increase of lymphokine-activated killer activity in seven of nine cases in whom lymphokine-activated killer activity had been poorly inducible even at high concentrations of recombinant interleukin 2. At the end of the treatment, liver tumor regression (34 and 63%, respectively, of two-dimensional size) was observed in two of two patients with a solitary tumor; no increase of liver tumor size was observed in seven patients with massive or multiple tumors, and no changes in the size or number of pulmonary metastatic tumors in any patients were observed. More than a 35% decrease in serum alpha-fetoprotein level was noted in four of nine alpha-fetoprotein-positive patients. However, Child's grades, performance status and lymphokine-activated killer activity on entry into the study could not be used as parameters to predict therapy responsiveness. Neither serious side effects nor significant changes of serum bilirubin, ALT and creatinine were noted. Thus, this treatment seems to be well tolerated even in advanced hepatocellular carcinoma with poor liver function reserve, and tumor regression could be expected in small-burden hepatocellular carcinoma. The assessment of the therapeutic effects and application in hepatocellular carcinoma awaits the development of this trial.

Aged↗