Biomedical subjects

H Yuasa

Publications and source records attributed to H Yuasa.

At least 37 records · Page 2Linked to original sources

PubMed2000

Carrier-mediated transport of riboflavin in the rat colon.

Carriers involved in riboflavin transport have generally been presumed to be localized in the upper small intestine. However, using a closed loop technique, we found that in the rat colon the absorption of riboflavin could be significantly reduced by raising the concentration from 0.1 to 200 microM and by adding lumiflavin, an analogue of riboflavin. These results suggest that saturable transport by the carrier that is specific for riboflavin and analogues may also be involved in riboflavin absorption in the colon. At the lower concentration of 0.1 microM, carrier-mediated transport was suggested to prevail, compared with passive transport, both in the colon and the small intestine. Furthermore, carrier-mediated transport in the colon was comparable with that in the small intestine. This study is the first to suggest carrier-mediated riboflavin transport in the colon. Although the riboflavin transport system in the colon needs to be subjected to more detailed investigation of its transport functions and role in riboflavin absorption after oral administration, it would be of interest to explore potential use of this carrier as a system for drug delivery.

Animals↗

PubMed2000

Species variation in the intracellular localization of pyruvate, Pi dikinase in leaves of crassulacean-acid-metabolism plants: an immunogold electron-microscope study.

In malic enzyme-dependent crassulacean-acid-metabolism (ME-CAM) plants, malic acid is decarboxylated by NADP-ME and NAD-ME and generates pyruvate with CO2. Pyruvate is phosphorylated to phosphoenolpyruvate by pyruvate, Pi dikinase (PPDK) and is then conserved in gluconeogenesis. Although PPDK was considered to be located in chloroplasts (e.g., Mesembryanthemum crystallinum), it has recently been found to accumulate in both the chloroplasts and the cytosol in two Kalanchoë species. In this study, the intracellular localization of PPDK was investigated in 22 ME-CAM species in 13 genera of 5 families by immunogold labeling and electron microscopy. This revealed that the pattern of intracellular localization of PPDK varies among the ME-CAM plants and is divided into three types: Chlt, in which PPDK accumulates only in the chloroplasts; Cyt-Chlt, in which PPDK accumulates in both chloroplasts and cytosol; and Cyt, in which PPDK accumulates predominantly in the cytosol. Members of a particular genus tend to have a common PPDK-localization type. In the Cactaceae, all species from seven genera were classified as Cyt. The photosynthetic tissues of all ME-CAM species, including the Cyt type, had substantial PPDK activity, suggesting that PPDK in the cytosol is active and probably plays a functional role. In the Chlt species, NADP-ME activity was relatively greater than NAD-ME activity. In the Cyt-Chlt and Cyt species, however, either the activity of NAD-ME was higher than that of NADP-ME or they were approximately the same. The species variation in the intracellular localization of PPDK is discussed in relation to CAM function and to molecular and phylogenetic aspects.

Blotting, Western↗

PubMed2000

Pachymeningitis with pseudo-Foster Kennedy syndrome.

PURPOSE: To report a case of pachymeningitis with pseudo-Foster Kennedy syndrome in a patient who was positive for perinuclear antineutrophil cytoplasmic antibody. METHODS: Case report. A 44-year-old man was examined for headache and diplopia. RESULTS: Left eye showed limitation of abduction. Ocular fundus, computed tomography (CT), and magnetic resonance imaging (MRI) of the head and orbits were normal. The diplopia subsided spontaneously. Six months later, he noticed sudden visual loss in the left eye. The left eye showed optic disk atrophy and episcleritis, and the right eye showed papilloedema. Computed tomography and MRI exhibited thickened dura mater. Serum perinuclear antineutrophil cytoplasmic antibody level was highly increased. CONCLUSION: Pachymeningitis with ocular involvement sometimes requires repeated CT or MRI for diagnosis. This disorder may be caused by microvasculitis.

Adult↗

PubMed2000

Serum antioxidant micronutrients and the risk of oral leukoplakia among Japanese.

A population-based case-control study was designed for the investigation of any association between serum micronutrient levels and oral leukoplakia. Out of a total of 9536 subjects over the age of 40 years who participated in the oral mucosal screening programme in Tokoname city, 48 cases detected with oral leukoplakia (38 male:10 female) were recruited. For each case, four controls matched by age and sex were selected from the same cohort. We examined the fasting serum levels of retinol, alpha-tocopherol, zeaxanthin and lutein, cryptoxanthin, lycopene and carotenoids (alpha-carotene and beta-carotene) by high-performance liquid chromatography. Among males with leukoplakia mean serum lycopene and beta-carotene levels (0.175+/-0.202, 0.357+/-0.295 micromol/l) were significantly lower than those of controls (0.257+/-0.252, 0.555+/-0.408 micromol/l) (P<0.05, P<0.005). Logistic regression analysis with leukoplakia as the dependent variable showed that high serum levels of beta-carotene were related to low risk of oral leukoplakia (odds ratio 0.160, 95% C.I.: 0.029-0.866, P<0.05). There were no significant differences in any of the serum nutrients estimated in female subjects. Our results suggest for the first time that high serum levels of beta-carotene may provide protection against oral precancer for the Japanese male.

Adult↗

PubMed2000

A new triterpenoid saponin from Isolatocereus dumortieri.

A new triterpenoid saponin, named dumortierinoside A, was isolated from Isolatocereus dumortieri. The structure was determined as dumortierigenin 3-O-alpha-L-rhamnopyranosyl (1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glucuronopyranoside (1) on the basis of NMR and mass spectroscopy.

Hydrolysis↗

PubMed2000

Administration of human chorionic gonadotropin with a controlled-release function to immature rats for application in male infertility therapy.

Biodegradable poly(DL-lactic acid) (PLA) devices with controlled release of human chorionic gonadotropin (hCG) were fabricated in a 2-mm cylinder form by the meltpressing technique. The devices fabricated were inserted subcutaneously in the backs of immature rats. It was found that the serum level of testosterone (T) remained constant at approximately 0.7 ng/ml for an experimental period of 14 days, resulting in greater Leydig cell production of testosterone. This was also suggested from the results of immunohistochemical observation of the testis and weight changes of prostates, such as the ventral prostates and seminal vesicle.

Absorbable Implants↗

PubMed2000

Analysis of the vasopressin system and water regulation in genetically polydipsic mice.

Polydipsic mice, STR/N, which show extreme polydipsia and polyuria, were discovered in 1958. In the STR/N, urine outputs are much higher than in control mice. The possibility of an abnormal regulation of the arginine vasopressin (AVP) system, or an abnormality in the renal susceptibility to AVP, should be considered. In this study we investigated the AVP system and water regulation in STR/N. We sequenced the AVP and the AVP V(2)-receptor genes of the STR/N by direct sequencing. No mutation was found in either of them. AVP gene expression examined by in situ hybridization and plasma sodium in 8-wk-old STR/N was significantly lower than in control mice, whereas it was significantly higher at 20 wk. Renal sensitivity to injected AVP was attenuated in 20-wk-old STR/N. The suppression of AVP synthesis due to excessive water retention in 8-wk-old STR/N suggests that polydipsia may be the primary cause in this strain. The 20-wk-old STR/N became dehydrated with the acceleration of AVP synthesis, which might have resulted from secondary desensitization to AVP.

Amino Acid Sequence↗

PubMed2000

Uptake of fractionated heparin by two types of scavenger receptors in isolated rat Kupffer cells.

The uptake of fractionated heparin was examined in the absence and presence of anionic proteins such as acetylated low density lipoprotein (Ac-LDL) and maleylated bovine serum albumin (Mal-BSA) to characterize the scavenger receptors involved in the uptake of fractionated heparin in isolated rat Kupffer cells. The uptake of fractionated heparin was completely inhibited by Ac-LDL and dextran sulfate, but only partially by Mal-BSA. Kinetic analysis revealed that the binding capacity (Bmax) of the Mal-BSA-insensitive receptor was significantly larger than that of the Mal-BSA-sensitive one, though their dissociation constants (Kd) were not significantly different. The apparent internalization rate constant (kint,app) was significantly larger for the Mal-BSA-sensitive receptor than for the Mal-BSA-insensitive one. Thus, the scavenger receptors involved in the uptake of fractionated heparin in Kupffer cells can be classified into two types, in terms of sensitivity to Mal-BSA. Mal-BSA-sensitive receptors have been characterized in macrophages and classified as class A. The Mal-BSA-sensitive one found in Kupffer cells in this study may belong to class A, while the Mal-BSA-insensitive one has been little characterized elsewhere.

Animals↗

PubMed2000

Bovine protein C inhibitor has a unique reactive site and can transiently inhibit plasmin.

Protein C inhibitor (PCI) regulates the anticoagulant protein C pathway by neutralizing activated protein C and thrombin-thrombomodulin complex in the human hemostatic system. In this study, we cloned a full-length bovine PCI cDNA encoding a putative 19-residue signal peptide and a 385-residue mature protein; this showed 70.6%, 70.6%, 57.5% and 59.6% amino acid sequence homology with the human, rhesus monkey, rat and mouse PCIs, respectively. Bovine PCI mRNA (2.1 kb in size) was expressed strongly in the liver, and moderately in the kidney and testis, but not in other tissues tested. Bovine PCI has a putative reactive site peptide bond, Lys-Ser, that is different from the reactive site sequence (Arg-Ser) of other species' PCI. We found that bovine PCI transiently inhibits bovine plasmin, but not human plasmin. Western blot analysis showed that the reactive site of bovine PCI is cleaved during the course of complex formation with bovine plasmin; degraded PCI is released from the complex gradually concomitant with the recovery of plasmin activity. These findings suggest that bovine PCI plays a role not only in the protein C pathway but also in the fibrinolytic activity of bovine hemostatic system.

Amino Acid Sequence↗

PubMed2000

[A case of malignant fibrous histiocytoma of the chest wall].

A case of malignant fibrous histiocytoma of the chest wall. A 56-year old man was admitted to the hospital with a complaint of showing abnormal shadow on chest X-ray. Chest X-ray and chest CT scan showed a calcified tumor of the chest wall. Histological diagnosis could not be made prior to the operation. Wide resection of the right chest wall containing the tumor and partial resection of the right lung were done. Malignant fibrous histiocytoma (MFH) showing a striform-pleomorfic pattern was recognized histologically with resected specimen. MFH commonly arises in the soft tissues of the extremities, but rarely in those of the chest. This paper also presents a review of 38 reported cases of MFH originated from the chest wall.

Histiocytoma, Benign Fibrous↗

PubMed2000

[An autopsy case of corticobasal degeneration without prominent cortical pathology--an imitator of progressive supranuclear palsy].

We describe an autopsy case of parkinsonism with bradykinesia, muscle rigidity, and dementia as major symptoms. The patient had developed bradykinesia at the age of 62, and then muscle rigidity, a parkinsonian posture, bradylalia, and dementia gradually appeared. Neurological examination revealed rigidity in the neck and limbs, with motion and speech being generally slow. He lacked involuntary movements including alien hand, tremor, chorea, and dystonia. Vertical gaze palsy, both upward and downward was noted, but other cranial nerves were intact. He was diagnosed as suffering from PSP clinically based on vertical gaze palsy, bradykinesia, instability on standing and gait, and dementia. Levodopa was only transiently effective. Within three years he became bed-ridden and in a state of akinetic mutism. At age 65 he died from pneumonia. Neuropathology revealed severe neuronal degeneration and gliosis in the substantia nigra. Because atrophy of the tegmentum of brainstem, dentate nuclei, inferior olivary nuclei was very mild and Alzheimer neurofibrillary tangles in the brainstem were relatively few, PSP was ruled out. Cortical neuronal degeneration was not apparent, but in the deep layer of cingulate gyrus, frontal lobe, and insula, there were several ballooned neurons. Gallyas-Braak silver staining showed no tuft-shaped astrocytes, specific for PSP, but it disclosed astrocytic plaques in the basal ganglia and the cerebral cortex. At present, astrocytic plaques are recognized as a hallmark of corticobasal degeneration (CBD), along with ballooned neurons in the cerebral cortex. The present case thus illustrates that CBD has a wide spectrum and may include cases in which degeneration of cerebral cortex is very mild.

Aged↗

PubMed2000

[Investigation for smoking cessation support on Internet. Internet survey of health and smoking awareness of users].

PURPOSE: This paper is intended as investigation of level of awareness of "health and smoking" of Internet users as a foundation to guide no smoking efforts on the Internet. METHODS AND SUBJECTS: A questionnaire was posted on a homepage only from September 1 to 30, 1999 only. RESULTS: There were 1687 valid responses. Respondents using a cellular phone with the Internet totaled 148. In reference to smoking, 47% of women and 54% of men replied when encountering "smoking by a stranger" that they were "a little troubled." As for "knowledge of medical treatment to stop smoking," over 70% of the respondents replied that they "only know it by name." In regards to responsibility of "who is wrong," respondents that answered "the country that is not regulated" were broken down into about 16% smokers and over 30% non-smokers. Personal computer users that are smokers accounted for 295 people, or 37.5%, and of the total respondents using a cellular phone with the Internet, 49 or 60.5% are smokers. Clearly these results are significant.

Adolescent↗

PubMed2000

[A case of sarcoid meningoencephalitis with an isolated supratentorial lesion].

A rare case of sarcoid meningoencephalitis with no systemic lesion is reported here. A 58-year old man was admitted experiencing dull headache and speech disturbance. He had never received a diagnosis of systemic sarcoidosis. On admission, neurological examination revealed dysarthria, a defect of the right-side visual field and accelerated right Achilles tendon reflex. A T2-weighted MRI showed a high-intensity signal in the white matter of the left parieto-occipital lobe surrounded by severe brain edema with a mass effect. The meninges around the lesion were enhanced by gadolinium, but no enhancement was observed in the basal portion. Angiotensin-converting enzyme (ACE) activities of cerebrospinal fluid (CSF) and serum were within normal range. The level of interleukin-6 in the CSF was slightly elevated. Chest X ray films and chest CT revealed no abnormal lesions. Whole body gallium scanning showed a hot region only in the intracranial lesion. A brain biopsy was performed. Histological examination revealed typical granuloma of sarcoidosis accompanied by microvasculitis and epithelioid cell granuloma without caseous necrosis. Oral administration of prednisolone improved all symptoms and MRI findings. These observations suggest that release of cytokines from macrophages and epithelioid cells, as well as disruption of the blood-brain barrier due to microvasculitis, are involved in the mechanism responsible for producing lesions of sarcoid meningoencephalitis.

Brain↗

PubMed2000

Synthesis and evaluation of alpha-fucosidase inhibitory activity of 5a-carba-alpha-L-fucopyranose and alpha-DL-fucopyranosylamine.

5a-Carba-alpha-L-fucopyranose and -alpha-DL-fucopyranosylamine were synthesized in conventional manner starting from 2,3,4-tri-O-acetyl-6-bromo-6-deoxy-5a-carba-beta-D- and -DL-glucopyranosyl bromides, respectively, and assayed for inhibitory activity against alpha-fucosidase (bovine kidney). Although the former proved to be only a moderate inhibitor (Ki = 4.3 x 10(-5) M), the latter could be shown to possess strong inhibitory potential (Ki = 2.3 x 10(-7) M). Diastereoisomeric imino-linked 5a'-carbadisaccharides were synthesized by coupling of the racemic 5a-carba-alpha-fucopyranosylamine and 1,6:3,4-dianhydro-2-azido-2-deoxy-beta-D-galactopyranose, in order to estimate approximately the inhibitory activity of individual optical antipodes of 5a-carba-alpha-fucopyranosylamine.

Animals↗

PubMed1999

Organization and chromosomal localization of the human endothelial protein C receptor gene.

Endothelial protein C receptor (EPCR), present on endothelial cells of relatively large veins and arteries, plays a role in the enhancement of protein C activation by the thrombin-thrombomodulin complex. In the present study, we determined the organization and the complete nucleotide sequence of the human EPCR gene using polymerase chain reaction-direct sequencing method. The transcription initiation site of the EPCR gene was also determined by the cap site hunting method, using a cap site cDNA prepared from human placenta. The human EPCR gene spanned approx. 6 kb and was composed of four exons and three introns. All exon-intron boundaries agreed with the GT-AG rule. The 5'-flanking region (300 bp) of the EPCR gene contained a putative AP1-binding site, two Sp1-binding sites and two AP2-binding sites, but not definite TATAA or CCAAT sequences. Fluorescence in situ hybridization analysis showed that the EPCR gene is located in chromosome 20q11.2.

Amino Acid Sequence↗

PubMed1999

Reduction of tablet coloration at tableting for oily medicine (tocopheryl nicotinate).

The powder (TN-PO) which adsorbed D,L-tocopheryl nicotinate (TN) as an oily medicine was prepared using porous calcium silicate (Florite(R)RE, FLR) as an adsorbing carrier. Tablets (TN-TAB) were produced by compression of TN-PO at different compression pressures. As TN-PO was compressed at the higher TN content in TN-PO and compression pressure, the more TN was exuded from TN-PO, and an increase in the degree of tablet coloration was observed. Therefore, FLR or colloidal silica (AEROSIL(R)200, AER) was newly added to TN-PO at compression to reduce the degree of tablet coloration. Further, the effects of addition of FLR or AER on the crushing strength, friability, porosity and disintegration property of the tablet and the dissolution property of TN from the tablet were studied. After addition of FLR or AER, a similar reduction of tablet coloration was observed. When the addition percentage of FLR to TN-PO exceeded 30%, the crushing strength of the tablet increased significantly. On the other hand, when TN-PO added with AER was compressed, no change was observed in the crushing strength of the tablet. The disintegration time of the tablet with added FLR was shorter than that of the tablet with added AER. At every addition percentage studied, the tablet with added FLR showed a higher releasing ability of TN compared with the tablet with added AER. These results indicate that it is possible to reduce tablet coloration by adding FLR or AER at compression of TN-PO. Further, it is considered that the differences in the crushing strength, disintegration property and dissolution property of TN between the tablets with added FLR or AER resulted in different liquid adsorbing and holding mechanisms of FLR particles and AER particles.

Antihypertensive Agents↗

PubMed1999

Affinity of 5-thio-L-fucose-containing Lewis X (LeX) trisaccharide analogs to anti-LeX monoclonal antibody.

5-Thiofucose-containing LeX trisaccharide analogs Gal beta(1,4)[5SFuc alpha(1,3)]GlcNAc-OMe (2) and Gal beta(1,4)[5SFuc beta(1,3)]GlcNAc-OMe (4) were synthesized via 5-thiofucosylation of methyl 2-azido-lactoside derivative 6 by the trichloroacetimidate method. Inhibitory activity of these analogs for the binding of LeX to anti-Lex antibody was evaluated by enzyme immunoassay, indicating that anti-LeX strictly recognizes alpha-configuration of the fucose moiety and its binding pocket includes no advantageous region, such as hydrophobic area, for recognizing the ring sulfur atom of 5-thiofucosyl LeX analog 2.

Antibodies, Monoclonal↗

PubMed1999

Syntheses of two trimannose analogs each containing C-mannosyl or 5-thio-C-mannosyl residue: their affinities to concanavalin A.

C-Mannosyl residue-containing trimannose ManC alpha(1,6)[Man alpha(1,3)Man] (2) and 5-thio-C mannosyl residue-containing trimannose 5SManC alpha(1,6)[Man alpha(1,3)Man] (3) were synthesized via a glycosyl radical addition to enone derivative of mannose (6). Dissociation constants for the binding of these trisaccharides to concanavalin A (ConA) were determined by a fluorescence anisotropy inhibition assay: Kd = 198 and 31 microM, respectively. The unexpectedly large Kd value for the compound 2 compared with the compound 3 and the natural trimannose 1 demonstrates a characteristic of C-glycoside.

Concanavalin A↗