Biomedical subjects

Y Morimoto

Publications and source records attributed to Y Morimoto.

At least 19 recordsLinked to original sources

PubMed1992

Concentration of serum laminin and type IV collagen in liver diseases assayed by a sandwich enzyme-immunoassay using monoclonal antibodies.

Serum laminin (P1 fragment) and type IV collagen levels were determined in patients with hepatic disorders. The method was based on a sandwich enzyme-immunoassay using two monoclonal antibodies that recognize different epitopes of either laminin or type IV collagen molecule. Laminin and type IV collagen levels in the serum of patients with chronic hepatic disorders were higher as compared with those in healthy control subjects, with the increment of serum type IV collagen being far greater than that of laminin. Since type IV collagen and laminin are major basement membrane components, it is suggested that the higher levels of these peptides may reflect a so-called capillarization of the perisinusoidal wall encountered in hepatic fibrogenesis. The assay system used in this experiment is simple and sensitive and can be applied to clinical evaluation of hepatic fibrosis.

Adolescent↗

PubMed1992

Effects of substitutions of glycine and asparagine for serine132 on activity and binding of human lipoprotein lipase to very low density lipoproteins.

For studying the role of Ser132 in the putative catalytic site of human lipoprotein lipase (LPL), mutant LPL cDNAs expressing LPLs with amino acid substitutions of Gly or Asn for Ser132 were obtained by site-directed mutagenesis, and were expressed in COS-1 cells. Considerable amounts of LPL enzyme protein mass were detected in the culture medium of COS-1 cells transfected with wild-type LPL, LPL-Gly132, or LPL-Asn132. LPL-Gly132 hydrolyzed Triton X-100-triolein and tributyrin as effectively as wild-type LPL, whereas LPL-Asn132 showed no activity. LPL-Asn132 bound to very low density lipoproteins as effectively as wild-type LPL.

Amino Acid Sequence↗

PubMed1992

Mechanism of skin penetration-enhancing effect by laurocapram.

In order to clarify the mechanism of action of laurocapram (Azone) on the skin permeation of drugs, the following experiments were done. First, the effect of Azone on the skin components was compared with that of other penetration enhancers. Azone markedly fluidized liposomal lipids (as a model lipid system) compared with other enhancers. Ethanol extracted large amounts of the stratum corneum lipids, whereas Azone did not. These results suggest that the effect of Azone on the lipids in the stratum corneum is not the same as that of ethanol. In addition, ethanol increased the amount of free sulfhydryl (SH) group of keratin in the stratum corneum, whereas Azone did not directly affect the stratum corneum protein. Azone increased water content in the stratum corneum, as measured by skin conductance. This effect might be a reason for the action of Azone. For further understanding, the enhancing effects of Azone on the skin permeation of several model compounds (alcohols, sugars, and inorganic ions) were compared with the effects of pretreatment with distilled water, which was thought to increase water-holding capacity, and pretreatment with ethanol, which was thought to affect the lipids and protein in the skin barrier (i.e., stratum corneum). Pretreatment with water or ethanol enhanced skin permeation of hydrophilic compounds, whereas they decreased that of octanol, a hydrophobic compound. The tendency of Azone to increase or decrease the skin permeation rate of most compounds was similar to that of pretreatment with water or ethanol. However, the effect of Azone on the skin permeation of inorganic ions was relatively low, whereas that of pretreatment with water or ethanol was high.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohols↗

PubMed1992

A novel protease obtained from FBS-containing culture supernatant, that processes single chain form hepatocyte growth factor to two chain form in serum-free culture.

The recombinant human hepatocyte growth factor (r-hHGF) produced by Chinese hamster ovary cells transfected with hHGF cDNA (CHO BD-24 cells) was the two chain form in fetal bovine serum (FBS) containing culture. However, in serum-free culture the non-processed r-hHGF, single chain form, was detected with two chain form r-hHGF. We purified the protease that proteolytically processed single chain r-hHGF to two chain form r-hHGF. A protease was purified to give a single peak from the culture supernatant by use of several column chromatographies. When this protease was added to serum-free culture of CHO BD-24 cells, the proteolytic processing of single chain r-hHGF to two chain form r-hHGF was completely achieved. This protease was found to be composed of two peptide chains with molecular mass of 38 kDa under non-reducing condition by SDS-PAGE. The results of N-terminal amino acid sequence analysis and inhibitor selectivity suggested that this protease was a novel serine protease originating from fetal bovine serum.

Amino Acid Sequence↗

PubMed1992

Characterization of the transcallosal response in aged rats and its susceptibility to nootropic drugs.

The transcallosal response in aged rats was recorded and its susceptibility to certain nootropic drugs was compared with adult animals, under urethane-anesthesia. The transcallosal response in 24-month old rats was significantly reduced in the amplitude of both positive and negative waves, as compared with 5-month old animals. In adult rats, intravenous administration of 100 mg/kg of calcium hopantenate augmented the amplitude of both the positive and the negative waves. Intraperitoneal administration of 300 mg/kg of calcium hopantenate or 10-100 mg/kg of aniracetam increased the amplitude of the negative wave by 20-30% above the control level but had no effect on the positive one. In aged rats, these drugs, given intraperitoneally, also increased the negative wave without affecting the positive one and the degree of augmentation was more prominent; both drugs increased the amplitude of the negative wave by about 190% of the control. These results suggest that the susceptibility to the nootropic drugs became even more striking in older animals, the function in the brain of which are reduced by the natural ageing process.

Aging↗

PubMed1992

XELE--a polypeptide model-building program for a graphics workstation.

A model-building program, XELE, for use in protein crystallography has been written in C under UNIX on a graphics workstation. This program makes full use of the X Window system to display the electron density distribution and to manipulate the polypeptide model, and therefore is named XELE. It utilizes a fast three-dimensional rendering package, Dorè, and is portable to other types of graphics workstations. A part of the program for the man-machine interface uses the library of X Window and X Toolkit, and therefore is highly interactive. The structure analysis program package, PROTEIN, is also implemented in an interactive mode using X Window, and has been interfaced with XELE.

Computer Graphics↗

PubMed1992

Trypsin treatment may impair the interfacial activation action of lipoprotein lipase.

Lipoprotein lipase was expressed in Chinese hamster ovary (CHO) cells transfected with human lipoprotein lipase cDNA. The lipoprotein lipase retained tributyrin, water-soluble substrate, hydrolyzing activity (esterase activity). The catalytic action of this enzyme was studied by monitoring the esterase activity. The esterase activity was enhanced 4.5-fold by the addition of triolein emulsified with Triton X-100. This process was named interfacial activation. Treatment of LPL with trypsin (100 micrograms/ml, 37 degrees C for 10 min) caused the loss of the triolein hydrolyzing activity without that of the esterase activity. The esterase activity of trypsin-treated LPL was not enhanced by the addition of the triolein emulsion. The trypsin-treated LPL retained the ability to bind to very low density lipoproteins (VLDL). These results are consistent with the idea that LPL has a catalytic site and a lipid interface recognition site, and that the enzyme undergoes interfacial activation, in which the concealed catalytic site is revealed after the enzyme binds to the surface. Based on this hypothesis, the results obtained suggest that trypsin nicking may impair the interfacial activation process and cause the loss of the lipase activity.

Animals↗

PubMed1992

Intraoperative measurement of lumbar spinal instability.

To justify lumbar fusion or stabilization, a quantitative assessment and definition of spinal instability are essential. To quantify spinal instability, the tensile stiffness of a motion segment (vertebra-disc-vertebra) was measured with a spinal distractor during spinal decompression surgery. Stiffness was indicated by the relationship between load and displacement between the two adjacent spinous processes where a vertebral spreader was suspended. A load-displacement curve was recorded at each step of surgical decompression and fixation while the motion segment was being distracted at a constant speed. The device used for measuring stiffness of a spinal motion segment is a lumbar spinal spreader with a load strain gauge and a displacement transducer. The stiffness of a spinal motion segment was reduced as disc degeneration developed. Degenerative spondylolisthetic discs showed the least stiffness (lowest, 3.9 N/mm; average, 5.4 N/mm). The stiffness of herniated discs, however, was relatively greater (average, 11.8 N/mm). The stiffness of normal motion segments was greater than affected segments. If the stiffness of a motion segment before decompression was graded as 100, it was reduced to 82% after partial laminectomy and facetectomy and to 65% after discectomy on average. After interbody fusion by iliac bone graft, it increased to 133% and to 184%, after Luque fixation.

Female↗

PubMed1992

Prediction of skin permeability of drugs: comparison of human and hairless rat skin.

Relationships between skin permeability and physicochemical properties of drugs were examined to establish a predictive method for the steady-state permeation rate of drugs through human skin. Human skin permeation properties fell into two categories: one in which the permeability coefficient is correlated to the partition coefficient, revealed with lipophilic drugs; and the other in which the permeability coefficients are almost constant, shown with hydrophilic drugs. The stratum corneum, the main barrier in skin, could be considered as a membrane with two parallel permeation pathways: lipid and pore pathways, and an equation for predicting the steady-state permeation rate of drugs was derived. The skin permeabilities of drugs for man were compared with those for hairless rat. The species difference in skin permeability found was suggested to be due to the difference in skin permeation pathways, since lipid content and water uptake of the stratum corneum varied between human and hairless rat skin.

Animals↗

PubMed1992

Synthesis and biological activities of optical isomers of 2-(4-chlorophenyl)-5,6-dihydro-(1)benzothiepino[5,4-c]pyridazin-3(2H)-o ne 7-oxide.

Two enantiomers of 2-(4-chlorophenyl)-5,6-dihydro-(1)benzothiepino[5,4- c]pyridazin-3(2H)-one 7-oxide ((+/-)-1: Y-23684) were synthesized in high yields by asymmetric oxidation of the synthetic precursor (2) using modified Sharpless reagent. Among the oxidants tested, cumene hydroperoxide (CHP) gave the highest optical and chemical yields, while tert-butyl, tert-amyl, and 1,1,3,3-tetramethylbutyl hydroperoxides did not show such high enantio-selectivities. The absolute configuration of (+)-1 enantiomer synthesized from 2, Ti(O-iso-Pr)4, (-)-diethyl tartarate, and CHP was determined to be S by X-ray crystallographic analysis. Both enantiomers, S-(+)-1 and R-(-)-1, and (+/-)-1 had approximately equivalent in vivo activities to antibicuculline test in mice and anticonflict test in rats, although S-( + )-1 showed about three times higher affinity to benzodiazepine receptor than R-(-)-1 in [3H]diazepam binding assay.

Animals↗

PubMed1992

Prodrugs of 2',3'-dideoxyinosine (DDI): improved oral bioavailability via hydrophobic esters.

Five ester prodrugs of 2'3'-dideoxyinosine (DDI) were synthesized for the purpose of improving oral bioavailability. The prodrugs, acetate (C2-DDI), octanoate (C8-DDI), stearate (C18-DDI), benzoate (Bz-DDI), and hemisuccinate (Suc-DDI) were proved to quantitatively regenerate their parent drug by enzymatic hydrolysis. Though the chemical stability of the prodrugs under acidic conditions was not improved, their solubility in water was significantly decreased by esterification, except for Suc-DDI. Bioavailability was evaluated by oral administration to rats. Two hydrophobic prodrugs (C8-DDI and Bz-DDI) showed higher absolute bioavailability (23.5% and 31.0%, respectively) than did DDI (15.2%), though that of C2-DDI (11.5%) and Suc-DDI (4.5%) was poor.

Administration, Oral↗

PubMed1992

Oily drug carriers in cancer chemotherapy. II. Preparation of viscous ethyl oleate for intraarterial infusion therapy and its disposition in rats and hamsters.

Viscous ethyl oleate (VEO) was prepared as an oil drug carrier by the addition of aluminum stearate or ethyl cellulose. Since the rate of shear of VEO containing aluminum stearate was greatly and nonlinearly changed against the shearing stress compared to that containing ethyl cellulose, the latter was used for subsequent microvascular and organ distribution experiments in rats and hamsters. For infusion into the carotid artery in hamsters, neat ethyl oleate (EO, 4cP) or VEOs of various apparent viscosities (40, 80, 120 cP-VEOs) embolized the vascular system in the cheek pouch, although arrival time to the site where the embolization was observed and the embolization period differed depending on the type of oily drug carrier. For infusion into the hepatic artery in rats, however, only 120 cP-VEO embolized the vascular system in the liver. After infusion of the oily drug carrier containing 3H-oleic acid into the artery of hamster cheek pouch and rat liver, 30-50% of the radioactivity was gradually eliminated within 48 h, whereas about 80% of the dose was rapidly eliminated after infusion to rat stomach and kidney. In addition, the amount of 120 cP-VEO remaining in each organ 48 h after infusion was higher than those of EO and 40 and 80 cP-VEOs. Histological observation after infusion in rat liver revealed that 120 cP-VEO slowly migrated from the artery or arteriole to the sinusoidal capillary region. These results suggest that 120 cP-VEO can be used as a drug carrier because of its function of vascular embolization and high retention in a targeted tissue.

Animals↗

PubMed1992

Effects of fatty acids, fatty amines and propylene glycol on rat stratum corneum lipids and proteins in vitro measured by fourier transform infrared/attenuated total reflection (FT-IR/ATR) spectroscopy.

Fourier transform infrared/attenuated total reflection (FT-IR/ATR) spectroscopy was used to examine the effect of fatty acids, fatty amines and propylene glycol (PG) on the molecular mobility of rat stratum corneum lipids and keratinized proteins, using a hydrophobic solute, indomethacin, and a polar solute, 5- and 6-carboxyfluorescein (CF). Treatment of the skin with either oleic acid or oleylamine resulted in significant CH2 C-H asymmetric stretching band shifts and broadening. The extent of spectral alteration varied with the chemical structure of the penetrant. The penetrants increased the lipophilic indomethacin flux and shortened the lag times through the skin in vitro. The plot of frequency changes vs. indomethacin flux or lag time demonstrated a linear relationship, thus indicating that spectral alteration in CH2 C-H stretching regions of stratum corneum lipids may provide a reliable index for characterizing penetrants. The data also showed that the hydrophilic group which attached to the CH2 group in the penetrant molecules did not play a part in the membrane permeability enhancing action. Oleic acid and oleylamine appeared to induce a conformational alteration of the keratinized proteins from alpha-helix to beta sheet. Such alteration was also observed with PG treatment. Accumulation of CF was significantly increased by the PG pretreatment of the skin, thus suggesting that PG-induced protein conformational changes could be related to the enhancement of CF accumulation.

Amines↗

PubMed1992

Calculation of skin permeability coefficient for ionized and unionized species of indomethacin.

The contribution of ionized and unionized species to the overall permeation of weak electrolytes through the skin was investigated to determine the effect of pH in the vehicle on the permeability of indomethacin (IDM), as a model drug, through hairless rat skin. The permeability of IDM through polydimethylsiloxane (silicone) and poly(2-hydroxyethyl methacrylate) (pHEMA) membranes which may reflect lipid and aqueous pathway, respectively, was also measured for comparison. As the pH in the vehicle increased, there was an exponential increase in the skin permeation rate of IDM. The permeation rate of IDM through the silicone membrane was constant independent of pH, whereas that through the pHEMA membrane increased with increasing pH, similar to the skin permeation. The permeability coefficients of ionized and unionized species through the skin estimated using the skin permeation rates and solubilities of IDM at various pHs were 1.50 x 10(-7) and 2.79 x 10(-5) cm/s, respectively. These results indicated that the permeation of ionized species greatly contributed to the total permeation of IDM at higher pH, and that the total permeation rate of IDM was determined by the permeation of unionized species at lower pH. These contributions depend on the pH and pKa values and the ratio of permeability coefficient of each species. It was also confirmed that the skin has at least two kinds of permeation pathways and these two species permeate through a different pathway.

Administration, Cutaneous↗

PubMed1992

Destabilization of whole skin lipid bio-liposomes induced by skin penetration enhancers and FT-IR/ATR (Fourier transform infrared/attenuated total reflection) analysis of stratum corneum lipids.

Whole skin lipid bio-liposomes (skin bio-liposomes), in size ranging from 2 to 8 microns, were prepared by a reverse phase evaporation technique using rat full thickness skin. Leakage of an encapsulated fluorescence probe, ANTS (delta-amino-1,3,6-naphthalene-trisulfonate), was measured by adding transdermal penetration enhancers (penetrants) into the medium where the skin bio-liposomes were present. Oleylamine induced a fast release of ANTS from the liposomes compared to lauryl-amine which showed a weak action. With these penetrants, the degree of ANTS release from the prepared bio-liposomes was found to correlate well with the results of frequency changes in the CH-asymmetric stretching band near 2920 cm-1 in the rat stratum corneum. The penetrant which caused relatively strong leakage of ANTS induced the significantly large shift of the peak toward the higher wave-numbers due to the perturbation in the structure of lipids of the stratum corneum. The skin bio-liposomes prepared from the rat full thickness skin could be useful in evaluating the penetrants.

Amines↗

PubMed1992

Anisoosmostic liver perfusion: redox shifts and modulation of alpha-ketoisocaproate and glycine metabolism.

1) In isolated perfused rat liver, 14CO2 production from [1-14C]alpha-ketoisocaproate or [1-14C]glycine as well as ketogenesis from alpha-ketoisocaproate were stimulated upon exposure to hypoosmotic perfusion media, whereas hyperosmotic exposure inhibited. The effects of anisotonicity were preserved when ketogenesis from alpha-ketoisocaproate and 14CO2 production from [1-14C]glycine were already stimulated by glucagon. On the other hand, ketogenesis from tyrosine (2 mM) or octanoate (0.1 mM) were almost unaffected by anisoosmotic exposure. 2) With all ketogenic substrates studied, hypoosmotic (hyperosmotic) cell swelling (shrinkage) decreased (increased) the beta-hydroxybutyrate/acetoacetate ratio in effluent perfusate. A shift of the mitochondrial and cytosolic NADH systems to a more oxidized (reduced) state following hypoosmotic (hyperosmotic) exposure was also found upon infusion of beta-hydroxybutyrate/acetoacetate and lactate/pyruvate as redox indicator metabolite couples. The effects of anisotonicity on the beta-hydroxybutyrate/acetoacetate ratio were reversible upon normoosmotic reexposure and persisted throughout anisoosmotic exposure despite completion of volume regulatory K+ fluxes within 10-15 min. Hepatic oxygen consumption decreased by about 10% during hyperosmotic cell shrinkage and was transiently stimulated during hypoosmotic exposure. 3) There was a close relationship between ketogenesis from alpha-ketoisocaproate (0.5 mM) and the mitochondrial redox state, as assessed by the beta-hydroxybutyrate/acetoacetate ratio in effluent, regardless of whether the pathway was modulated by anisotonicity or glucagon. 4) Isoosmotic cell swelling induced by addition of glutamine (3 mM) was without significant effect on ketogenesis from octanoate and stimulated ketogenesis and 14CO2production from [1-14C]alpha-ketoisocaproate only slightly (i.e. by less than 10%); however, in each case the hydroxybutyrate/acetoacetate ratio in effluent perfusate decreased by about 20% upon addition of glutamine. 5) Stimulation of 14CO2production from [1-14C]glycine by hypoosmotic exposure and glucagon was only slightly affected when the accompanying decrease of the beta-hydroxybutyrate/acetoacetate ratio was reversed by addition of beta-hydroxybutyrate. 6) The data are compatible with a hypotonicity (hypertonicity)-induced shift of the mitochondrial NADH system to a more oxidized (reduced) state, probably due to a alterations of respiration. Mitochondrial swelling probably also occurs under the influence of glutamine. Modulation of ketogenesis from alpha-ketoisocaproate, but not of glycine oxidation by anisoosmotic exposure and glucagon can be related to the accompanying redox shifts. The observations support the concept that cell volume may be an important parameter determining liver cell function.

Animals↗

PubMed1992

Semi-quantitative analysis of early microleakage around amalgam restorations by fluorescent spectrum method: a laboratory study.

Rhodamine B, a fluorescent substance, was used as a tracer to investigate in vitro early microleakage from around amalgam restorations in machinable mica glass-ceramic after thermal stress. Five types of amalgam, i.e., low-copper spherical, low-copper lathe-cut, high-copper admixture, high-copper lathe-cut, and high-copper spherical, were examined in the present study. The results indicated that early microleakage from alloys of lathe-cut particles was lower than that from alloys of spherical particles in both low-copper and high-copper amalgam restorations. A high-copper amalgam with a mixture of lathe-cut and spherical particles tended to exhibit the lowest early microleakage.

Ceramics↗

PubMed1992

[Study of postgastrectomy fatty liver].

Fatty liver was often found concomitantly by the ultrasound during the follow up study of the gastric cancer operation. By ultrasound, development of postgastrectomy fatty liver was seen in 29 out of 176 patients (16.5%) with several gastrectomies. The number of the patients with postgastrectomy fatty liver was 12 out of 104 patients (11.5%) with distal partial gastrectomy with B-I reconstruction, while that was 17 of 72 patients (23.6%) with total gastrectomy with several reconstructions. The incidence of postoperative fatty liver change was significantly higher in the patients under 59 years old compared to the elders. Seventy-five g oral glucose test induced oxyhyperglycemia and hyperinsulinemia in patients with gastrectomy, especially with total gastrectomy. Integrated plasma insulin and triglyceride responses during first one hour in postgastrectomy patients were significantly higher than preoperative values. Moreover, plasma insulin and blood sugar in response to oral glucose test were significantly higher in patients with postgastrectomy fatty liver, compared to those in patients without fatty liver. These results suggested that the postgastrectomy fatty liver was resulted from the abnormality of the glucose metabolism.

Age Factors↗