Search PubMed⌕ Search

Biomedical subjects

K Higaki

Publications and source records attributed to K Higaki.

At least 73 records · Page 4Linked to original sources
PubMed1994

The orientation of primary cilia during the wound response in 3Y1 cells.

The behavior of the primary cilia of 3Y1 cells in the interphase was investigated by indirect immunofluorescence microscopy and transmission electron microscopy, using an antibody for tubulin. At 4.5 h after scraping a part of a confluent cell sheet, the primary cilia of cells facing the wound were located predominantly forward of the nucleus on the wounded side, and were oriented in the direction of the leading lamellae. Cytoplasmic microtubules (MTs), emanating from around the base of the cilia, were well developed in the leading lamellae on the wounded side. On the other hand, in the cells of an unperturbed area away from the wounded edge, the primary cilia remained randomly distributed near the nucleus. The position and a certain well-defined orientation of a pair of centrioles seem to play an important role for the development of cytoplasmic MTs, and consequently the orientation of the centrioles is controlled by the primary cilia.

Animals↗
PubMed1994

Squamous cell carcinoma of the ovary--a case report.

A 68-year-old woman presented a one-month history of lower abdominal pain and weight loss, and was admitted to our hospital. On physical examination, a large hard mass was palpated in her right lower abdomen. An ultrasonograph and computed tomographic (CT) scan revealed a right ovarian tumor that measured 6.9 x 4.9 cm in size. A total hysterectomy and bilateral salpingo-oophorectomy were performed. The postoperative diagnosis of the tumor was squamous cell carcinoma (SCC) of the ovary. She died of infection and disseminated intravascular coagulation 5 months after surgery. The clinical and autopsy examinations did not show the primary lesions of SCC except in the right ovary. Mature cystic teratoma, Brenner tumor and endometriosis, which are ordinary regarded as the histogenesis of ovarian SCC, were not found, but a few surface epithelial inclusion cysts with squamous metaplasia were observed in non-cancerous area of the right ovary, and the contiguous transition from the metaplastic cyst wall to SCC was confirmed by stepwise serial sections. The present case suggests that the surface epithelium of ovary could be the fourth possibility in the histogenesis of the ovarian SCC.

Aged↗
PubMed1994

Stereoselective renal tubular secretion of an organic anion in the isolated perfused rat kidney.

To clarify the stereoselective renal tubular secretion of an organic anion, renal excretion of 5-dimethylsulfamoyl-6,7-dichloro-2,3-dihydrobenzofuran-2-carbox yli c acid (DBCA), a racemic compound, was studied with a single-pass perfused rat kidney preparation under constant perfusion pressure (ca. 120 mm Hg). The steady-state renal extraction ratio of (R)-(+)-DBCA (0.134) was 10 times higher than that of (S)-(-)-DBCA (0.015), indicating high selectivity for (R)-(+)-DBCA. The urinary excretion rate and renal excretory clearance (CLrex) were 4 times larger for (R)-(+)-DBCA, and the unbound fraction in the perfusate also was higher for (R)-(+)-DBCA (R/S = 1.58). Fractional excretion (FE) and intrinsic clearance for tubular secretion (CLrsec,int) were about 3 times larger for (R)-(+)-DBCA than the antipode, showing the stereoselectively predominant secretion of (R)-(+)-DBCA. The N-monodemethylated metabolite, M-1, was found only for the R-(+)-enantiomer in the perfusate and urine, revealing highly stereoselective N-monodemethylation in the kidney. The CLrsec,int value for (R)-(+)-M-1 was 2.5 times larger than that for (R)-(+)-DBCA. The perfusion study using each enantiomer decreased R/S ratios of the extraction ratio (9.9), urinary excretion rate (3.9) and excretory clearance (3.9) in the perfusion of the racemate to 3.9, 2.1 and 2.1, respectively. No significant difference was found between (R)-(+)- and (S)-(-)-DBCA in FE and Clrsec,int. The declined stereoselectivity in renal excretion parameters may be due to competitive inhibition of the tubular secretion of (R)-(+)-DBCA by the (R)-(+)-M-1 formed which possessed greater secretion ability in the (R)-(+)-DBCA perfusion study, whereas (S)-(-)-DBCA was secreted without great inhibition by (S)-(-)-M-1 in the (S)-(-)-DBCA perfusion because of a small amount of generated metabolite. Plotting of FE ratios of DBCA enantiomers to (R)-(+)-M-1 against FE of (R)-(+)-M-1 suggests that the actual FE for (R)-(+)-DBCA was 2 times larger than that for (S)-(-)-DBCA, and that (S)-(-)-DBCA secretion was inhibited more easily by (R)-(+)-M-1.

Animals↗
PubMed1994

[Experimental studies on immunotargeting therapy for esophageal carcinoma].

We produced two types of murine monoclonal antibodies, KYSM-1 and KIS-1, against human squamous cell carcinoma of the esophagus for quantitative diagnosis and optimum therapy. The isotypes of KYSM-1 and KIS-1 were IgM and IgG1, respectively. Immunohistochemical staining demonstrated that both antibodies strongly reacted with human carcinoma cell lines of the esophagus, lung and oral cavity. Fluorescence activated cell sorter analysis demonstrated that each antigen of KYSM-1 and KIS-1 exposed to cellular membrane of squamous carcinoma cells and molecular weights of these antigens detected by KYSM-1 and KIS-1 were 60 kDa and 90 kDa, respectively, in non-reduced condition. These 2 monoclonal antibodies were labeled with 125I by the Iodogen method, and each antibody was injected into nude mice with human squamous cell carcinoma of the esophagus. Regarding in vivo accumulation of 125I-labeled antibodies, however, KIS-1 alone showed significantly high values in the tumor at 5 and 7 days after the injection. From this result, KIS-1 was labeled with 131I and injected into the tumor-bearing mice with a dose of 200 microCi. Moderately effective results were found in the tumor by 14 days after the injection. Furthermore, KIS-1 was also conjugated to peplomycin (PEP). In in vitro and in vivo effects of targeting chemotherapy, the conjugates killed human squamous carcinoma cells and tumor-implanted nude mice. These results suggest that the 131I-labeled KIS-1 and/or KIS-1-PEP conjugate may provide a targeting therapy in patients with squamous cell carcinoma of the esophagus.

Animals↗
PubMed1993

Enantiomer-enantiomer interaction of a uricosuric antihypertensive diuretic (DBCA) in renal tubular secretion and stereoselective inhibition by probenecid in the cynomolgus monkey.

1. Enantiomer-enantiomer interaction of 5-dimethylsulphamoyl-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxyl ic acid (DBCA), a uricosuric, diuretic and antihypertensive agent, was studied from the pharmacokinetics of the enantiomers following intravenous injection of individual enantiomers and racemate into male cynomolgus monkeys. Also studied was the involvement of the anion transport system in the renal excretion of DBCA by comparison of the pharmacokinetics in probenecid-treated and non-treated animals. 2. Separate administration of individual enantiomers showed higher plasma concentrations of (S)(-)-DBCA than those of the antipode, at an early period after dosing. Both enantiomers disappeared rapidly from plasma with an elimination half-life (t1/2 beta) of 0.35-0.38 h. Unbound fractions were 18.9% for the (R)(+)-enantiomer and 10.2% for the (S)(-)-enantiomer. The major portion of both enantiomers was excreted by 6 h after dosing and 77-78% of the dose was recovered within 48 h, principally as the unchanged drug. Tubular secretion contributed significantly to the renal excretion of DBCA, because tubular secretion clearance values of unbound drug (CLrf,s) were 14- to 29-fold greater than creatinine clearance. 3. The presence of the antipode decreased the tubular secretion clearance (CLrf,s) value of unbound (S)(-)-enantiomer by 30%, and tended to decrease that for the unbound (R)(+)-enantiomer, although not significantly. This indicates the occurrence of enantiomer-enantiomer interaction in the process of renal tubular secretion, and the inhibition of (S)(-)-DBCA renal excretion in the presence of the antipode. 4. Probenecid treatment significantly decreased the CLrf,s of both enantiomers, and the extent of inhibition for the (S)(-)-enantiomer (53%) was significantly higher than that for the antipode (14%). These results show that renal tubular secretion of DBCA involves an anion transport system which prefers the (S)(-)-enantiomer, and that probenecid can preferentially inhibit (S)(-)-enantiomer secretion.

Animals↗
PubMed1992

Stereoselective pharmacokinetics of a novel uricosuric antihypertensive diuretic in rats: pharmacokinetic interaction between enantiomers.

5-Dimethylsulfamoyl-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxyli c acid (DBCA), a promising uricosuric, diuretic, and antihypertensive agent, was administered intravenously to rats. The levels of DBCA in plasma and the areas under the curve of concentration versus time (AUC values) of the S(-)-enantiomer were higher than those of the R(+)-enantiomer. Total body clearance was significantly greater for the R(+)-enantiomer. This stereoselective elimination was due to a difference in the nonrenal clearance, which seemed to reflect hepatic metabolism or biliary excretion. Hepatic metabolism seemed more likely because AUC and the amount of urinary excretion of the N-monodemethylated metabolite of DBCA were greater for the R(+)-enantiomer. The plasma had higher free fractions of the S(-)-enantiomer, a result suggesting that this enantiomer is distributed more readily to the tissues, including the liver. This result indicates that protein binding was not responsible for the stereoselective metabolism of (R)-(+)-DBCA. Although there was no difference in the renal clearances of the enantiomers, the renal clearance of free (R)-(+)-DBCA exceeded that of the S(-)-enantiomer, a result indicating the preferential excretion of the R(+)-enantiomer into the urine. Comparison of the pharmacokinetics of individual enantiomers after intravenous administration of each enantiomer or its racemate showed that the enantiomers interact with one another; dosing with racemate delayed the elimination of each enantiomer because of mutual inhibition of hepatic metabolism and renal excretion for (R)-(+)-DBCA and of renal excretion for (S)-(-)-DBCA.

Animals↗
PubMed1990

Effect of medium-chain glycerides on the intestinal absorption of phenol red: studies on mechanisms of the promoting effect.

To elucidate the mechanisms of the promoting action of medium-chain glyceride (MCG) on the intestinal absorption of phenol red (PR), the effect of different MCG dose levels on PR absorption, the absorption kinetics of MCG itself, and the mucosal reduced glutathione (GSH) levels were investigated to determine whether or not they are related to the promoting action of MCG. The absorption of PR was found to be enhanced with an increase in MCG dose (as an emulsion in the range 0.5-4.0%). Urinary excretion of PR was reduced by absorbed MCG components, which also resulted in an increase in the AUC. Moment analysis of plasma PR concentrations after intraintestinal administration revealed a shorter mean absorption time (MAT) for the emulsion formulation than for the control. The mucosal GSH level was lowered by the administration of the MCG emulsion (2-10%) into the intestinal lumen. Pretreatment with a 4% MCG emulsion decreased GSH levels to one-half of the control. In these cases, the level of mucosal GSH seemed to remain constant to the end of the experiment after it had decreased during the initial period. On the other hand, results from the in situ loop or recirculation study showed that enhancement of PR absorption appeared in the earlier period and then gradually decreased. The time course of the PR absorption rate, estimated from plasma concentration data, was similar to that of the MCG absorption rate. These results suggest that the promotion of intestinal absorption is related to the absorption kinetics of MCG itself, but not directly to the level of mucosal GSH.

Animals↗
PubMed1990

Effect of medium-chain glycerides on the membrane transport of D-glucose and sulfanilic acid in the intestinal brush-border membrane vesicles.

To clarify the influence of medium-chain glycerides (MCG) on a biological membrane, we investigated the membrane transport of D-glucose and sulfanilic acid in the brush-border membrane (BBM) vesicles pretreated with MCG. The size distribution of the BBM vesicles determined by electron microscopic observation was not significantly different between the vesicles incorporated with MCG and those of the control. However, the amount of D-glucose taken up by the vesicles at an equilibrated stage (30 min) was significantly decreased in the MCG-treated ones based on unit content of protein. Based on these results we estimated the membrane transport of D-glucose and sulfanilic acid in consideration of vesiculation or filter-capturing efficiency in MCG-treated vesicles. The rates of Na+ gradient-independent D-glucose transport and sulfanilic acid transport were significantly greater in MCG-treated vesicles than in the control. On the other hand, the magnitude of overshooting effect in Na+ gradient-dependent uptake of D-glucose in MCG-treated vesicles was maintained similar to the control. Comparison of kinetic parameters for active D-glucose transport at different concentrations indicated that Km and Vmax were not significantly different between MCG-treated and the control vesicles. These results indicated that passive diffusion of D-glucose and sulfanilic acid was significantly increased but Na(+)-glucose cotransporter was not significantly changed by the incorporation of MCG in the intestinal BBM vesicles.

Benzenesulfonates↗
PubMed1988

Enhanced membrane permeability to phenol red by medium-chain glycerides: studies on the membrane permeability and microviscosity.

To clarify the mechanism of the drug absorption enhancement by medium-chain glycerides (MCG), the changes in membrane permeability provoked by MCG were investigated with liposomal uptake experiments. Uptake of phenol red (PR) into liposomes increased with an increase in MCG content in the liposomal membrane, suggesting that PR absorption was enhanced in the "transcellular route." However, the apparent membranous microviscosity obtained in fluorescence depolarization studies tended to increase with the addition of MCG in both the hydrophobic core and the polar head regions of the liposomal membrane. Thus, an enhancement in membrane permeability caused by MCG was not accompanied by a decrease in the apparent membranous microviscosity.

Absorption↗
PubMed1987

[The role of canine hepatic sinusoidal lining cells in the immune response: analysis by mixed lymphocytes-sinusoidal lining cells culture].

The ability of canine sinusoidal endothelial cells (SEC) and Kupffer cells (KC) to function in several in vitro immunologic systems was investigated. Isolated sinusoidal lining cells (SLC) from canine liver were separated by centrifugal elutriation into structurally intact SEC and KC fraction with purities of 65% and 78%, respectively. In this study, it has been demonstrated that SEC and KC are found to be potent stimulators of mixed lymphocyte culture and they are capable of functioning as accessory cells for the activation of mitogen induced T cell. OKIal positive cells constituted 76.2% of SEC and 15.7% of KC. These Ia positive cells played an important role as stimulators in those responses, since the stimulating activity of both cells was lost by pretreatment with anti-Ia monoclonal antibody (OKIal) plus complement. In addition, lymphocytes stimulated with SEC and KC were cytotoxic for PHA blasts of the stimulator dogs. But lysis of autologous or third party allogeneic targets was virtually absent or low. These results indicate that SEC and KC stimulate allogeneic lymphocytes and the efferent phase of cell mediated cytotoxicity is induced by these cells. So SLC, especially SEC and KC, may play an important role in liver allograft rejection.

Animals↗
PubMed1986

Effect of medium-chain glycerides (MGK) on the intestinal absorption and the hepatobiliary transport of bromthymol blue.

The effect of medium chain glyceride (MGK) emulsion on the intestinal absorption and the biliary excretion of bromthymol blue (BTB) was investigated in rats. Extensive tissue accumulation of BTB was reduced when BTB was administered with MGK emulsion formulation. HCO-100, an emulsifier, was also important for the decrease in the tissue accumulation of BTB. The ratios of absorption percent to tissue accumulation percent and to free fraction, not contained in the droplet of emulsion, in MGK emulsion were much greater than that of the control. Pretreatment with BTB-free emulsion reduced BTB absorption under the control, although tissue accumulation was not affected. The absorption appeared to decrease with increase in the time of pretreatment. The effect of leaving treatment after pretreatment on the absorption of BTB was also investigated. With the increase in leaving time after pretreatment, reduced absorption tended to resume to the level of control. The change in monocaprylate content from 54 to 60% in MGK made a difference in BTB absorption and it was suggested that monocaprylate content in MGK was one of the significant factors of MGK emulsion on drug absorption. Bile recovery study was simultaneously carried out with an in situ recirculation experiment. The recovery of BTB into bile tended to decrease. The ratio of recovery percent of BTB into bile to the absorption percent of BTB also decreased extensively, which is possibly another effect of MGK on drug disposition.

Animals↗