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Biomedical subjects

A Tsuji

Publications and source records attributed to A Tsuji.

At least 19 recordsLinked to original sources
PubMed1995

Participation of a proton-cotransporter, MCT1, in the intestinal transport of monocarboxylic acids.

A molecular mechanism for the intestinal monocarboxylic acid transport was characterized by using a proton/monocarboxylate transporter, MCT1, in Chinese hamster ovary (CHO) cells, first found by Garcia et al. (Cell, 76, 865-873, 1994). Northern blotting analysis showed that MCT1-isomers exist in the rat and rabbit intestinal enterocytes and Caco-2 cells. The expression of [14C]lactic acid uptake by Xenopus laevis oocytes injected with rabbit intestinal mRNA was reduced by hybridizing the mRNA with a MCT1 cDNA of CHO cells before microinjection used as the antisense DNA. [14C]Lactic acid uptake by CHO cells was pH dependent, saturable, stereospecific, and reduced in the presence of acetic acid, benzoic acid, S- and R-ibuprofen, S- and R-mandelic acid, nicotinic acid, pravastatin, propionic acid and valproic acid. In addition, several monocarboxylic acids were transported in pH-dependent and saturable manners. These results suggest that the intestinal MCT1-related protein contributes to a carrier-mediated absorption for organic weak acid compounds.

Animals↗
PubMed1995

Species differences in hydrolysis of isocarbacyclin methyl ester (TEI-9090) by blood esterases.

Species differences in the hydrolysis of isocarbacyclin methyl ester (TEI-9090) in whole blood and in its separated components were studied in rats, dogs and human. Esterase activity in rat whole blood was approximately 100 and 400 times higher than that in dog and human whole blood, respectively, and was attributed to high plasma activity. In contrast, TEI-9090 hydrolysis activities in dog and human blood were due to red blood cells (RBC), whose activity in humans was slightly suppressed by albumin. In dogs, activity in RBC membranes was 10 times greater than in the cytosol, while in human membrane and cytosol activity was virtually the same. The effects of the esterase inhibitor diisopropylfluorophosphate, bis-p-nitrophenylphosphate (BNPP), eserine, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and p-chloromercuribenzoate showed that the rat plasma and RBC cytosol esterases hydrolysing TEI-9090 were carboxylesterase (CarbE) and arylesterase (ArE), respectively. The esterases in dog plasma and RBC membrane were CarbE, and RBC cytosol esterase was ArE. In humans, the esterase activities in plasma, RBC membrane and cytosol were butyrylcholinesterase, CarbE and ArE, respectively.

Animals↗
PubMed1995

In vivo and in vitro evidence for ATP-dependency of P-glycoprotein-mediated efflux of doxorubicin at the blood-brain barrier.

We investigated the role of ATP in the active efflux of doxorubicin (DOX) mediated by P-glycoprotein (P-gp), the multidrug-resistance (MDR) gene product, at the blood-brain barrier. In transient brain ischemic rats prepared with 4-vessel occlusion of vertebral and common carotid arteries for 20 min, a procedure that depleted their brain ATP content to 3% that of normal rats, the estimated permeability coefficient of DOX was increased 17-fold (to 243 +/- 2.5 microL/min/g brain). When the ATP content recovered to a normal level by means of 30-min and 24-hr cerebral recirculation of blood, the permeability coefficient recovered to 14.0 +/- 5.0 and 18.4 +/- 2.3 microL/min/g brain (mean +/- SEM, N = 3-6), respectively, very close to the control permeability (14.3 +/- 1.5 microL/min/g brain). The uptake of DOX by primary cultured brain capillary endothelial cells expressing P-gp at the luminal membrane was increased significantly (up to 2-fold), which correlated well with the decrease of cellular ATP contents caused by treating the cells with metabolic inhibitors. Evidence for the ATP-dependent transport of DOX obtained from the present in vivo and in vitro studies strongly indicates that P-gp in the brain capillaries functions actively as an efflux pump in the physiological state, providing a major mechanism to restrict the transfer of DOX into the brain.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Comparison of casual blood pressure and twenty-four-hour ambulatory blood pressure in high school students.

OBJECTIVE: To perform ambulatory blood pressure monitoring (ABPM) in high school students and to compare the 24-hour values with casual blood pressure (BP). METHODS: Ambulatory BP monitoring was carried out in 190 high school students, 15 or 16 years of age, with elevated casual BP during the first examination at school for hypertension; 66 had elevated casual BP at both the first and the second examinations (group H1), and 124 students were normotensive at the second examination (group H2). Sixty-two students who were consistently normotensive served as control subjects (group N). Average BPs for the 24-hour period, the awake period (10 AM to 10 PM), and the sleeping period (1 AM to 6 AM) were calculated. RESULTS: Average BP for each period was significantly higher in group H1 than in group N. Average BP in group H2 for these periods was intermediate between those of group H1 and of group N. The casual BP had a significant positive correlation with the average BP during the awake period (r = 0.55, p < 0.01 for systolic BP; r = 0.37, p < 0.01 for diastolic BP). In most subjects the casual BP readings were higher than BP during ABPM. CONCLUSIONS: Casual BP measurements correlated with 24-hour BP, but they tended to be higher than the measurements obtained during 24-hour ABPM.

Adolescent↗
PubMed1995

Hepatic uptake of octreotide, a long-acting somatostatin analogue, via a bile acid transport system.

The hepatic transport mechanism of octreotide (Sandostatin), a somatostatin analogue, was studied using freshly prepared rat hepatocytes. The initial uptake rate of octreotide represented exclusively a saturable transport process. The half-saturation constant, Kt, and the maximum uptake-rate, Jmax, for the uptake of octreotide were 91.1 +/- 28.4 microM and 104.6 +/- 19.7 pmol/mg protein/min, respectively. An energy requirement was demonstrated for [14C]octreotide uptake since metabolic inhibitors (DNP, rotenone, antimycin and NaCN) significantly reduced the initial uptake rate. [14C]octreotide uptake was also significantly inhibited by ouabain. [14C]octreotide uptake was reduced in the absence of Na+ in the uptake medium. [14C]octreotide uptake was significantly inhibited by bile acids, iodipamide, d-tubocurarine, whereas it was not inhibited by bilirubin, TEMA and insulin. Competitive inhibition of taurocholic acid was observed for octreotide uptake with the inhibition constant, Ki, of 82 +/- 17 microM. Moreover, a significant inhibitory effect of octreotide was observed for the Na+ dependent uptake of [14C]taurocholic acid. These results suggest that octreotide is transported into hepatocytes via a bile acid carrier-mediated system.

Amino Acid Sequence↗
PubMed1995

Correlation of Tc-99m GSA hepatic studies with biopsies in patients with chronic active hepatitis.

To determine whether scintigraphic findings of Tc-99m DTPA-galactosyl-HSA (GSA) correspond to histopathologic findings, Tc-99m GSA hepatic scintigraphy and biopsy were compared in 65 patients with chronic active hepatitis. After injecting 185 MBq of Tc-99m GSA, anterior images were obtained at 5 minutes and 15 minutes. Scintigrams were classified into three grades according to the extent of visualization of the cardiac blood pool on 5 minute and 15 minute images. Biopsies were subjectively graded for findings of necrosis and fibrosis. Scintigraphic grades on 5 minute images were correlated with hepatic necrosis and fibrosis and those on 15-minute images with hepatic fibrosis. Scintigraphic abnormalities of Tc-99m GSA correlated well with histopathologic abnormalities, especially with hepatic fibrosis and necrosis in patients with chronic active hepatitis.

Adult↗
PubMed1995

Distribution of the Kexin family proteases in pancreatic islets: PACE4C is specifically expressed in B cells of pancreatic islets.

The distribution of Kexin family proteases in adult rat pancreatic islets was investigated by immunohistochemical means using a series of specific antibodies specific for PC1, PC2, PC6, Furin, PACE4A and a recently identified member of the Kexin family, PACE4C. PACE4C expression was limited to B cells of the pancreatic islets. PC2 was found in A and in some D cells more than in B cells and PC1 was evident only in B cells. Furin and PC6 were weakly and evenly expressed in the entire islet. PACE4A was hardly found in the islets. These findings indicated that individual Kexin family proteases are uniquely distributed in the islets and suggested that these proteases share roles in these cells as follows: PC2 is involved in the peptide hormone precursor processing in A cells and in D cells, and PACE4C, PC1 and PC2 (mainly PACE4C and PC1) are responsible for the processing event(s) specific to B cells.

Animals↗
PubMed1995

Immunoblastic lymphadenopathy-like T-cell lymphoma displaying rearrangement of both IgH and TCR beta genes after 4-year follow-up of idiopathic eosinophilia.

Immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma (IBL-T) occurred in a 60-year-old female after a 4-year follow-up of idiopathic eosinophilia and upper pharyngeal inflammatory tumor with infiltration of mature eosinophils. Gene analysis of tumor cells revealed rearrangement of both IgH and TCR beta genes. The patient died of lymphoma seven months after the onset of the illness, in spite of chemotherapy against lymphoma. The relationship between eosinophilia and the pathogenesis of IBL-T, as well as the significance of the rearrangement of both IgH and TCR beta genes are discussed.

Eosinophilia↗
PubMed1995

[The advantage of a thin flexible ureteroscope with a new real-time processing system].

To observe the upper urinary tract more clearly with a thin flexible endoscope, we developed a novel real-time processing system. This system enhances the parts of the dark cladding around the core by individual strong brightness of each image fiber. The upper urinary tract in eight patients was examined using a thin flexible endoscope with this system at retrograde pyelography or at urological operation. Six patients had hydronephrosis and 2 had filling defects in the renal pelvis or calyx. The endoscope was 0.75 mm in diameter and had 300 pixels of image fiber. The objective portion could be assessed successfully in seven of eight. Significantly finer and colorful image could be obtained with this system compared with the conventional method and the epithelium could be clearly observed. We conclude that this real-time processing system remarkably improves the quality of image obtained with the thin flexible ureteroscope and makes it a more promising modality in the diagnosis and treatment of the upper urinary tract.

Adult↗
PubMed1995

[Expression of GP160 mRNA in renal cell carcinoma: an attempt to predict the sensitivity of IFN-alpha therapy].

BACKGROUND: Alpha-interferon (IFN-alpha) has significant antitumor activity against advanced renal cell carcinoma (RC). Although numerous clinical trials reported major responses in approximately 15% of patients subjected to INF-alpha therapy, it has been impossible to predict which patients will respond to IFN-alpha. RC cell lines could be subdivided into those that are inhibited by IFN-alpha and those that are not. The expression of GP160 (Aminopeptidase a/kidney-associated differentiation antigens) correlated with resistance to IFN-alpha. In RC xenografts using a mouse model, though GP160(+) RC cell lines were resistant to IFN-alpha, GP160(-) RC cell lines were markedly sensitive to IFN-alpha. METHOD: In this study, we assayed 26 RC patients for the expression of GP160 in mRNA level using RT-PCR (reverse transcription polymerase chain reaction). RESULTS & CONCLUSION: In 23 (88.5%) patients GP160 mRNA expression are remarkable as in normal kidney tissue, but in 2 (7.7%) patients, GP160 mRNA expression was weak. And in 1 (3.8%) patient, GP160 mRNA expression was hardly detectable, and in this patient complete remission was achieved with IFN-alpha therapy for advanced lung and mediastinal metastatic RC.

Adult↗
PubMed1995

Functional expression of transporter for beta-lactam antibiotics and dipeptides in Xenopus laevis oocytes injected with messenger RNA from human, rat and rabbit small intestines.

A heterologous gene expression system, Xenopus laevis oocytes, was used to prove the intestinal absorption of various beta-lactam antibiotics mediated by an H(+)-dipeptide cotransport system in rat, rabbit and human small intestines. The microinjection of mRNA (messenger RNA) from rat intestine into Xenopus laevis oocytes led to significantly higher uptakes of p.o. active cephalosporins including zwitter-ionic derivatives (cephalexin, cephradine and cefadroxil) and dianionic derivatives (cefixime and ceftibuten) in comparison with oocytes injected with water, whereas the uptake of cefazolin, a parenterally administered derivative, was negligible in both mRNA- and water-injected oocytes. The uptake of cefadroxil was reduced significantly in the presence of dipeptide and various beta-lactam antibiotics, but not in the presence of an amino acid. After sucrose density gradient centrifugation of mRNA, the highest expression of transport activities of both cefadroxil and ceftibuten was observed in the same mRNA fraction with a size of 2.20 to 3.75 kilobases. mRNA-injected oocytes showed a marked pH-dependency in the uptakes of cefadroxil and ceftibuten, whereas water-injected oocytes exhibited only modes uptakes. The most stimulated uptakes of cefadroxil and ceftibuten were observed at an external pH of 5.5 and 5.0, respectively. Furthermore, injection of mRNA isolated from either rat rabbit or human small intestine into oocytes produced significantly higher uptake of cefadroxil and ceftibuten compared with those by oocytes injected with water. Thus, intestinal absorption of p.o. active beta-lactam antibiotics was confirmed to be mediated by an H+ gradient-dependent transport system across the brush-border membrane of rats, rabbits and humans. The carrier-protein for this process is likely a dipeptide transport system.

Animals↗
PubMed1995

[Comparison of MICs of new quinolones obtained using agar-dilution and broth-microdilution procedures].

Minimum inhibitory concentrations (MIC) of new quinolones against both Gram-positive and Gram-negative bacteria obtained using agar-dilution and broth-microdilution procedures were compared. A primary regression curve and a correlation coefficient (r) between 2 MICs for each of ofloxacin, ciprofloxacin, tosufloxacin, sparfloxacin or balofloxacin were calculated. For the 5 quinolones, average correlation coefficients were 0.891 for the Gram-positive bacteria tested, and 0.865 for the Gram-negative bacteria. The range of, correlation coefficients for the Gram-positive bacteria for these drugs was from 0.835 to 0.919, and that for the Gram-negative bacteria was from 0.815 to 0.865. From these data, it is clear that there is a good correlation between the 2 MICs of the new quinolones obtained using the agar-dilution and the broth-microdilution procedures. It was also shown that the value of the slope of the regression curves were nearly the same for the 5 quinolones tested. However, some particular strains of Morganella morganii, Pseudomonas cepacia, Xanthomonas maltophilia, Pseudomonas aeruginosa and Streptococcus pneumoniae exhibited different correlation coefficients from other strains.

Bacteria↗
PubMed1995

[Congenital dermoid cyst over the anterior fontanelle: case report].

We report a case of a 35-month-old Japanese boy harboring a dermoid cyst in the region of the anterior fontanelle, which is rarely reported among Japanese. A small soft subcutaneous mass was noticed in the mid-frontal region at the age of 6 months. On admission, a soft, nontender round mass (2.5cm in diameter) was located over the anterior fontanelle. Transillumination was negative. Neurological examination yielded normal findings. MRI showed a well-circumscribed mass, which was slightly hypointense on T1W1 and hyperintense on T2W1. Midsagittal MRI showed no intracranial extension. At operation, a well-encapsulated mass was found beneath the pericranium, which was easily dissected from the underlying dura mater and removed. The tumor contained caseous material and several hairs. Microscopically, the cyst wall consisted of connective tissues lined by stratified squamous epithelium. Sebaceous glands and hair follicles were found in the subepithelial layer. It is important to confirm preoperatively whether or not the extracranial mass extends into the intracranial cavity. For this purpose, midsagittal or coronal MRI seems to be most useful.

Child, Preschool↗
PubMed1995

[A case of successful acute revascularization using a long vein graft].

We experienced a case of successful acute revascularization using a long vein graft. A 68-year-old man was admitted to our department due to transient ischemic attack of the left hemiparesis. CT scan showed no infarction, but PAO-SPECT revealed moderate hypoperfusion in the right ACA and MCA area. Cerebral angiography demonstrated right IC occlusion at its origin and moderate collateral circulation via leptomeningeal anastomosis from the PCA area, and via the external carotid system, especially directly from STA. But the STA was very narrow. Three days after admission, left hemiparesis appeared again and deteriorated severely. This time the hemiparesis persisted. Although MRI demonstrated little infarction in the right frontal lobe, we decided to carry out revascularization on the same day. Right saphenous vein was harvested for a graft because of the narrow STA. The facial artery and angular artery was selected as a donor and a recipient respectively, to avoid a clamp of the EC and a craniotomy of the STA running area. Finally we performed a facial artery-vein graft-angular artery (M4) bypass. The patient showed no complication and the left hemiparesis improved enough to allow the patient to walk by himself. Revascularization using vein graft is dangerous for acute ischemia due to the possibility of a complication such as brain edema and hemorrhagic infarction. The usual style of vein graft bypass is an EC-vein graft-M2 or M3 bypass. Using this style, high pressure inside the EC is carried intracranially.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

In vivo evidence for ATP-dependent and P-glycoprotein-mediated transport of cyclosporin A at the blood-brain barrier.

To evaluate the significance of P-glycoprotein (P-gp)-mediated active efflux on the blood-brain barrier (BBB) permeability of cyclosporin A (CsA) in vivo, we investigated the effects of ATP depletion in the brain and of a multidrug-resistant (MDR) reversing agent on the transport of CsA across the BBB. Using transient brain ischemia obtained by 4-vessel occlusion of vertebral and common carotid arteries in rats to deplete ATP content in the brain, the estimated permeability surface area product (PS) value of [3H]CsA was increased 2.7-fold compared with that in normal rats, whereas the PS value of [14C]sucrose was not altered. Additionally, when quinidine hydrochloride (QND) was infused into the brain through a microdialysis probe implanted in the rat hippocampus, the extravascular extraction of CsA was increased to approximately 2.5-fold of the control, whereas no difference in the extravascular extraction between control and normal rats having no implanted dialysis probe was observed. Furthermore, the efflux rate from brain to blood of CsA was decreased remarkably to 5% of control at steady-state by co-administration of CsA with QND directly into the brain through the dialysis probe. The ATP-dependent and QND-sensitive efflux of CsA from the brain strongly indicates that P-gp in the brain capillary endothelial cells functions as an efflux pump under the physiological state, and that P-gp-mediated efflux of CsA is a major mechanism of the restricted transfer from blood into the brain.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Analysis of polymerase chain reaction-product by capillary electrophoresis with laser-induced fluorescence detection and its application to the diagnosis of medium-chain acyl-coenzyme A dehydrogenase deficiency.

Capillary gel electrophoresis with laser-induced fluorescence (CGE-LIF) has been developed to detect polymerase chain reaction (PCR) amplified samples. LIF detection was performed using Thiazole Orange as the fluorescent intercalating dye. This method was ca. 100x as sensitive as that with UV detection. The highly sensitive CGE-LIF was applied to the detection of the most prevalent mutation (lysine329-to-glutamic acid substitution) in medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency. The disorder, which shows an autosomal recessive inheritance, is known to be highly prevalent among Caucasian population and often mimics as Reye-like syndrome or sudden infant death. A DNA fragment containing the mutation site was PCR-amplified with two sets of allele specific oligonucleotide primers, followed by CGE-LIF. The mutant allele produced a 175-base pairs DNA fragment, which the normal allele generated a 202-base pairs DNA fragment. CGE-LIF clearly distinguished these PCR products, facilitating rapid diagnosis of MCAD deficiency.

Acyl-CoA Dehydrogenase↗
PubMed1994

Functional expression of intestinal dipeptide/beta-lactam antibiotic transporter in Xenopus laevis oocytes.

An intestinal active transport system specific to small peptides and peptide-like drugs such as beta-lactam antibiotics was functionally expressed in Xenopus laevis oocytes after microinjection of messenger RNA (mRNA) derived from rat intestinal mucosal cells. The transport activity was evaluated by measuring the uptake of a tripeptide-like cephalosporin antibiotic, ceftibuten, which has high affinity for the intestinal peptide/H+ co-transporter and is resistant to peptidases. Ceftibuten transport in mRNA-injected oocytes was pH dependent (a proton gradient is the driving force), stereo selective (uptake of the cis-isomer of ceftibuten was about 4-fold higher than that of the trans-isomer), saturable and temperature dependent. Furthermore, various dipeptides showed cis-inhibitory and trans-stimulatory effects on the uptake of ceftibuten by mRNA-injected oocytes, suggesting that ceftibuten and dipeptides are transported by a common carrier protein. These results are in accordance with the functional properties of native proton-coupled peptide transporter previously clarified by studies with isolated intestinal brush-border membrane vesicles and other experimental systems. A protein with a molecular mass of about 130 kDa expressed in the membrane of mRNA-injected oocytes was identified as the transport protein by specific labeling with a photoreactive beta-lactam antibiotic, [3H]benzylpenicillin, followed by SDS-PAGE analysis of the radiolabeled protein. Furthermore, an experiment with mRNA size-fractionated by sucrose density gradient centrifugation indicated that the peptide transporter is encoded by mRNA of between 1.8 and 3.6 kb. These results, obtained using a heterologous gene expression technique, confirm that intestinal absorption of beta-lactam antibiotics occurs through a carrier-mediated mechanism and show that biologically stable beta-lactam antibiotics can be useful probes for molecular analysis of intestinal peptide transporter.

Affinity Labels↗