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Biomedical subjects

K Morimoto

Publications and source records attributed to K Morimoto.

At least 91 records · Page 5Linked to original sources
PubMed2000

Usefulness of liposomes as an intranasal dosage formulation for topical drug application.

The potential of liposomes as an intranasal dosage formulation for topical application was investigated in rats. When 5(6)-carboxyfluorescein (CF), a model absorbable drug, dissolved in phosphate-buffered saline (PBS) was administered intranasally, CF was rapidly absorbed into the systemic circulation and no adhesion of CF to the nasal mucosa was observed. The fraction of CF absorbed from the nasal mucosa reached about 48% 1 h after administration. On the other hand, only 3% of the dose was absorbed when CF was encapsulated in liposomes consisting of dipalmitoylphosphatidylcholine and cholesterol (DPPC-liposomes). In addition, the amount of CF adhering to the nasal mucosa after administration as DPPC-liposomes was 20- to 28-fold greater than that in PBS solution. In particular, positively charged liposomes markedly enhanced the adhesion of CF to the nasal mucosa. Differences in the lipid composition of liposomes did not affect the absorption of CF. However, the ability of liposomes to adhere to the nasal mucosa was consistent with the fluidity of the liposomal membrane. Furthermore, the action of liposomes on the anti-histaminic effect of diphenhydramine hydrochloride (DH) was studied in rats by measuring the amount of protein leaking into the nasal cavity under quasi-allergic conditions. The anti-histaminic effect of DH was strong but of short-duration when DH was administered as a PBS solution. However, liposomes prolonged the anti-histaminic effect of DH, suggesting that liposomes may adhere to the nasal mucosa and release DH slowly. In conclusion, liposomes suppress drug absorption into the systemic circulation and concurrently increase drug retention in the nasal cavity.

Administration, Intranasal↗
PubMed2000

Inhibitory effect of dexamethasone palmitate-low density lipoprotein complex on low density lipoprotein-induced macrophage foam cell formation.

We used low density lipoprotein (LDL) as a carrier of site-specific delivery of drugs to atherosclerotic lesions, prepared a dexamethasone palmitate (DP)-LDL complex, and examined the effect of the DP-LDL complex on foam cell formation of macrophages in vitro. LDL was isolated from human plasma and the DP-LDL complex was prepared by incubation in the presence of Celite 545. The complex contained about 50 mol of DP in 1 mol of LDL. When macrophages were incubated with LDL for 48 h, cholesterol ester was accumulated in the macrophages, indicating foam cell formation. This accumulation of cholesterol ester was significantly inhibited by incubation with the DP-LDL complex. The potency of the DP-LDL complex was similar to that of dexamethasone alone. The DP-LDL complex also significantly attenuated the accumulation of cholesterol ester induced by incubation with LDL prior to the incubation with the DP-LDL complex. These findings indicated that the DP-LDL complex showed similar characteristics to LDL, and the DP-LDL complex inhibited the foam cell formation of macrophages in in vitro experiments. This DP-LDL complex has a possibility as a drug-carrier complex for use in atherosclerosis.

Animals↗
PubMed2000

Bioavailability assessment of arginine-vasopressin (AVP) using pharmacokinetic-pharmacodynamic (PK-PD) modeling in the rat.

A novel method of assessing the extent of oral bioavailability of arginine-vasopressin (AVP) from pharmacological data was presented. After intravascular administration (i.v. bolus or short-term infusion) of AVP to rats, the relationship between blood concentrations and its effect on both mean arterial pressure (hemodynamic effect) and urinary sodium concentration (anti-diuretic effect) was described on the basis of an integrated pharmacokinetic-pharmacodynamic (PK-PD) model. A direct model was used for the hemodynamic response, while an indirect response model, rather than a hypothetical link model was used for the anti-diuretic response. A sigmoid Emax model was applied to describe the drug-receptor interaction. Pharmacological responses after intravascular administration of AVP were reasonably described by the PK-PD model. However, PD parameters estimated by the PK-PD analysis suggested that apparent receptor affinity rather than efficacy in i.v. bolus study was significantly higher than that in the short-term infusion study. This fact indicated that PK-PD relationship was influenced by the intravascular input rate of AVP. We then investigated the relationship between plasma concentration and amount of AVP bound to the V2 receptors in the kidney. The result indicated that the amount of AVP bound to the receptors after i.v. bolus injection was always greater than that after short-term infusion. Since the PK-PD relationship after oral administration was almost identical with that after short-term infusion, the PK-PD model obtained in the short-term infusion study was used to assess the extent of oral bioavailability (EBAPp.o.). The EBAp.o. values, estimated from pharmacological effects (hemodynamic effect and anti-diuretic effect) after oral administration of 5 microg/kg of AVP were 0.68% to 0.93% and were almost identical with the actual EBAPp.o. value (0.81%). From these results, we concluded that oral bioavailability of AVP was reasonably predicted by the PK-PD model, provided that appropriate pharmacological effects and appropriate intravascular dosing rate as a reference formulation are available. The method may be an alternative to methods based on plasma concentrations, when drug concentration cannot be measured and when appropriate pharmacological data are available.

Administration, Oral↗
PubMed2000

[Neurotoxicity of beta-amyloid].

Recent observations on the neurotoxicity of beta-amyloid have been reviewed and possible roles of racemization of beta-amyloid are discussed. beta 1-40, beta 25-35 and D-Ser26 beta 25-35 (all HCl salt forms), but not commercially available beta 1-40 (TFA salt form), take the beta-structure within few hours in PBS, form fibrils, exert toxic effects on hippocampal cultured neurons and suppresses MTT reduction activity of non-neuronal HeLa cells without cytotoxicity. D-Ser26 beta 1-40 is soluble and non-toxic in vitro but is converted by brain proteinases to D-Ser26 beta 25-35, a potent toxic and proteinase-resistant fragment. The co-injection of beta 1-40, D-Ser26 beta 25-35 or D-Ser26 beta 1-40 with ibotenic acid, but not beta-amyloid alone or ibotenic acid alone, into rat brains produce drastic neuronal loss in the hippocampal CA1 area. The in vivo degeneration activity of beta-amyloids is well correlated with their having beta-structure and activity to suppress the MTT reduction activity. A specific antibody against D-Ser26 beta 25-35 strongly reacts with hippocampal degenerated-CA1 neurons in AD but not control brains. These results suggest that D-Ser26 beta 25-35 and related peptides possibly generated from insoluble beta 1-40 due to aging exert toxic effects on the hippocampal CA1 pyramidal neurons by enhancing the susceptibility to excitatory amino acids.

Alzheimer Disease↗
PubMed2000

[Lifestyle and health].

The total environments to which individuals have been exposed throughout the lifestages from birth to the present time have been composing the individual and community lifestyles. Such lifestyles are known to determine the risks for developments of cancers, circulatory diseases, and other chronic diseases. To establish new theory and practice programs for disease prevention and health promotion in the environmental and preventive medicine, we have quantitatively investigated correlations of lifestyles, or ways of daily living, to comprehensive health potentials in the cohort of industrial workers. The total lifestyles were evaluated by the originally-designed 8 health-practices such as smoking, alcohol-drinking, physical exercise, and working and sleeping patterns. The data indicate that individuals having good lifestyles showed much younger health ages calculated based on the health-check-up data, and lower risks for developing lifestyle-related diseases than those with poor lifestyles. The physical health potentials were assessed by the biomarker-measurements such as lymphocyte chromosome-DNA alterations, natural-killer activities and serum IgE levels. The psycho-mental health potentials were evaluated by both the quality-of-life-related questionnaires and the stress-related hormonal and cytokine levels such as cortisol and interleukines. The comprehensive health potentials have been shown to be significantly lower in poor-lifestyle people than in good-lifestyle ones. The changes in poor to good lifestyles through health education and learning were also shown to result in promotion of such health potentials.

Chromosomes↗
PubMed2000

[Effects of Ramadan fasting on the health of Muslims].

The fasting month of Ramadan is the ninth lunar month of the Islamic calendar. It is the most important month for Muslims because in which the Qur'an was revealed, and they abstain from food and drink from dawn to sunset to express their gratitude to God. Eating and drinking is permitted only at night, and Muslims typically eat two meals each day, after sunset and just before dawn. People tend to stay up late watching TV with the family, praying or reading the Qur'an. Ramadan teaches Muslims self-restraint and reminds them of the feelings of the impoverished. On the other hand, the biological effects of changes in lifestyle during Ramadan may also be expected. Some studies have reported substantial weight loss, signs of dehydration, raised serum concentrations of uric acid and cholesterol, etc. during Ramadan. However, these changes are unlikely to have much effect on healthy individuals, because generations of Muslims have undertaken fasting year after year. In conclusion, the observance of the Ramadan fast may produce some ill-effects in patients with some disease, e.g. hypertension, hypercholesterolaemia, hyperuricaemia, hyperglycaemia, and heart, liver and kidney disease.

Cholesterol↗
PubMed2000

Molecular cloning, overexpression, and purification of a major xylanase from Aspergillus oryzae.

The gene encoding xylanase G2 (xynG2) was isolated from a genomic library of Aspergillus oryzae KBN616, used for making shoyu koji. The structural part of xynG2 was found to be 767 bp. The nucleotide sequence of cDNA amplified by RT-PCR showed that the open reading frame of xynG2 was interrupted by a single intron which was 71 bp in size and encoded 232 amino acids. Direct N-terminal amino acid sequencing showed that the precursor of XynG2 had a signal peptide of 44 amino acids. The predicted amino acid sequence of XynG2 has strong similarity to other family 11 xylanases from fungi. The xynG2 gene was successfully overexpressed in A. oryzae and the overpexpressed XynG2 was purified. The molecular weight of XynG2 estimated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 21,000. This was almost the same as the molecular weight of 20,047 calculated from the deduced amino acid sequence. The purified XynG2 showed an optimum activity at pH 6.0 and 58 degrees C. It had a Km of 5.1 mg/ml and a Vmax of 123 micromol/min/mg when birch wood xylan was used as a substrate.

Amino Acid Sequence↗
PubMed2000

Genotoxic effects of alpha-endosulfan and beta-endosulfan on human HepG2 cells.

alpha-Endosulfan and ss-endosulfan are isomers of endosulfan, a pesticide used worldwide. In this study, we examined the genotoxicity of [alpha]- and ss-endosulfan in vitro with a HepG2 cell line. We used sister chromatid exchanges (SCE), micronuclei (MN), and DNA strand breaks as detected by single-cell gel electrophoresis (SCG) assays as biomarkers to judge the genotoxicity of [alpha]- and ss-endosulfan at concentrations from 1 times 10(-12) M to 1 times 10(-3) M. After treating HepG2 cells for 48 hr with ss-endosulfan, SCE showed a significant increase at concentrations from 1 times 10(-7) M to 1 times 10(-5) M, and MN showed a significant increase at concentrations from 5 times 10(-5) M to 1 times 10(-3) M. [alpha]-Endosulfan failed to show significant effects in both the SCE and MN assays. After treating HepG2 cells with [alpha]- or ss-endosulfan for 1 hr, DNA strand breaks were significantly induced by [alpha]-endosulfan at concentrations from 2 times 10(-4) M to 1 times 10(-3) M, and by ss-endosulfan at 1 times 10(-3) M. The results of this study suggest that both [alpha]- and ss-endosulfan are genotoxic to HepG2 cells and that the genotoxicity of ss-endosulfan seems stronger than that of [alpha]-endosulfan.

Biomarkers↗
PubMed2000

Oral taurine supplementation prevents the development of ethanol-induced hypertension in rats.

Taurine is known to lower blood pressure in essential hypertension and some experimental hypertensive models. Taurine has also been reported to activate aldehyde dehydrogenase and to inhibit the elevation of plasma acetaldehyde concentration after ethanol intake. Because acetaldehyde, the first metabolite of ethanol, is suspected to be responsible for many adverse effects of alcohol consumption, we examined the effect of taurine supplementation on ethanol-induced hypertension and abnormalities in the intracellular cation metabolism in Witar-Kyoto rats. In Study 1, systolic blood pressure and intraplatelet free calcium were significantly higher in rats who received 15% ethanol in drinking water than in control rats. Oral taurine supplementation (1% taurine and 15% ethanol in drinking water) completely prevented the development of ethanol-induced hypertension. Intraerythrocyte sodium and intraplatelet free calcium were significantly decreased in taurine-supplemented rats as compared with rats who received 15% ethanol only. In Study 2, hemoglobin-associated acetaldehyde (HbAA) was measured as a marker of protein-bound acetaldehyde. HbAA was significantly elevated in rats who received 5% ethanol in drinking water as compared with control rats. Taurine supplementation (1% taurine and 5% ethanol in drinking water) significantly decreased HbAA. Our findings suggest that the oral supplementation of taurine prevents ethanol-induced hypertension by decreasing protein bound acetaldehyde and altering the cation handling by the membrane.

Acetaldehyde↗
PubMed2000

Relationships between cigarette smoking, alcohol drinking, the ALDH2 genotype and adenomatous types of colorectal polyps in male self-defense force officials.

Alcohol drinking as well as cigarette smoking has been associated with development of colorectal polyps, Asians such, as Japanese, Chinese and Korean have high frequency of genetic polymorphism in low Km aldehyde dehydrogenase (ALDH2) gene which greatly regulates alcohol intake. In the present study, we investigated associations of this polymorphism and lifestyles with colorectal polyps in self-defense forces personnels in Japan. All subjects received colonoscopy at a retirement health examination. The ALDH2 genotype was determined using polymerase chain reaction and restriction fragment length polymorphism method. Frequency of the ALDH2 genotype was not different between those with colorectal polyps (n=69) and those without the polyps (n=131). Smoking was associated with development of colorectal polyps (OR=4.7, 95% confidence interval=1.9-11.5) in the ALDH2 proficient genotype. The association appeared to be enhanced by drinking alcohol since a synergistic effect of smoking and alcohol drinking (> or =60 ml/day) was indicated (OR=9.9, 95% confidence interval=2.9-34.1) by logistic regression analysis. In the ALDH2 deficient genotype, however, we could not evaluate interactions of smoking and alcohol drinking on colorectal polyp development because of the small sample size of heavy alcohol drinkers. The genotype analysis would be useful in evaluating effects of environmental factors on outcomes for each genetically defined subpopulation.

Adenomatous Polyps↗
PubMed2000

Reinvestigation of the role of the rabies virus glycoprotein in viral pathogenesis using a reverse genetics approach.

The rabies virus glycoprotein (G) gene of the highly neuroinvasive and neurotropic strains SHBRV-18, CVS-N2c, and CVS-B2c was introduced into the non-neuroinvasive and less neurotropic SN-10 strain to provide further insight into the role of G in the pathogenesis of rabies. Phenotypic analyses of the recombinant viruses revealed, as expected, that the neurotropism of a particular rabies virus strain was a function of its G. Nevertheless, the pathogenicity of the recombinant viruses was, in every case, markedly lower than that of the wild-type viruses suggesting that while the G dictates neurotropism, other viral attributes are also important in pathogenesis. The low pathogenicity of the recombinant viruses is at least in part due to a strong increase in transcription activity. On the other hand, the production of infectious virus by the R-SHB18 recombinant virus-infected cells was significantly delayed by comparison with SHBRV-18 wild-type virus infected-cells. Replacement of the R-SHB18 G cytoplasmic domain, transmembrane domain, and stem region with its SN-10 G counterparts neither results in a significant increase in budding efficiency nor an increase in pathogenicity. These results suggest that an optimal match of the cytoplasmic domain of G with the matrix protein may not be sufficient for maximal virus budding efficiency, which is evidently a major factor of virus pathogenicity. Our studies indicate that to maintain pathogenicity, the interactions between various structural elements of rabies virus must be highly conserved and the expression of viral proteins, in particular the G protein, must be strictly controlled.

Amino Acid Sequence↗
PubMed2000

Accumulation of hemoglobin-associated acetaldehyde with habitual alcohol drinking in the atypical ALDH2 genotype.

BACKGROUND: Those with the atypical genotypes of low Km aldehyde dehydrogenase (ALDH2) have high blood concentrations of free acetaldehyde, an active metabolite of ethanol, after drinking alcohol. In the present study, we measured acetaldehyde reversibly bound to hemoglobin (HbAA) in Japanese male workers. METHODS: One hundred and sixty Japanese male workers in one plant participated with informed consent. The subjects were genotyped for the ALDH2 polymorphism by polymerase chain reaction method. HbAA levels were measured using a high performance liquid chromatography system with a fluorescence detector. For the study in which we examined accumulation of HbAA, eight Asian male volunteers participated with informed consent. RESULTS: Although HbAA levels were significantly correlated with recent alcohol consumption in both typical (ALDH2*1/*1) and atypical (ALDH2*1/*2) genotypes, the slope in ALDH2*1/*2 was significantly steeper than that in ALDH2*1/*1. Multiple regression analysis on relevant factors for HbAA revealed that not only recent but also daily alcohol consumption increased HbAA levels in those with the ALDH2*1/*2 genotype, which suggests that HbAA accumulates with habitual drinking. We measured HbAA levels before, during, and after alcohol consumption--one drink (0.4 ml/kg) per day--for 7 consecutive days in male volunteers. During the drinking period, HbAA linearly increased in ALDH2*1/*2 (n = 4) but not in ALDH2*1/*1 (n = 4). After reaching peak levels (+76.1 nmol/g hemoglobin) following the seventh drink, HbAA levels gradually decreased but were significantly higher for 3 days after drinking was discontinued. CONCLUSIONS: We demonstrated that HbAA levels accumulate with habitual alcohol drinking in the atypical ALDH2 genotype. HbAA was shown to be a good biomarker for increased internal exposure levels to acetaldehyde.

Acetaldehyde↗
PubMed2000

[Plasma cell leukemia presenting with circulating villous lymphocytes and an indolent clinical course].

A 73-year-old man was admitted to our hospital in July 1996 because of lymphoctyosis and lumbago. Physical examination revealed hepatomegaly and anemia. Hematologic examination showed a hemoglobin concentration of 9.6 g/dl and a leukocyte count of 32,700/microliter with 74% abnormal mononuclear cells. In Wright-Giemsa stained blood films, these cells had short villi arising from 1 or 2 poles. Immunophenotyping of peripheral mononuclear cells showed moderate to strong expression of CD10, CD24, CD38, and sIg lambda, but not of CD19, CD20, or CD25. Southern blot analysis of the peripheral mononuclear cells demonstrated rearranged monoclonal bands in the C lambda. Urine immunoelectrophoresis detected a monoclonal band identifiable as lambda-type Bence Jones protein. In addition, bone X-ray studies disclosed multiple osteolytic lesions. A diagnosis of plasma cell leukemia was made, and the patient was placed on chemotherapy consisting of cyclophosphamide and prednisolone. No notable improvement in laboratory findings was seen but the patient experienced an indolent clinical course. He died of pneumonia in January 1998. The morphological and clinical findings were unusual for a case of plasma cell leukemia. This case study suggested that signs of lymphocytosis require immunophenotypic and electron microscopic studies for the differential diagnosis of plasma cell leukemia.

Aged↗
PubMed2000

[Neonatal hydrocephalus-volume determinations using computed tomography].

Computed tomography potentially offers the most accurate noninvasive means of estimating in vivo volumes. Contiguous 5 and 10-mm-thick CT scans were obtained through phantom and neonatal cranium. Cross-sectional areas were calculated for each individual scan and volumes then determined with summation-of-areas technique. The indirect intracranial volume measurement technique was then used to compare hydrocephalic and non-hydrocephalic intracranial and ventricular volumes in nine neonates. Our findings show that intracranial volumes of hydrocephalic neonates with head circumference of more than 39 cm, have 1.97 times larger than control group. The ratios of lateral ventricle versus intracranial volume are 0.57 +/- 0.2 in hydrocephalic babies and 0.0062 +/- 0.001 in control babies, respectively(p < 0.005).

Brain↗
PubMed2000

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between April 1997 and March 1998].

The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobial susceptibility have been conducted in 19 facilities in Japan since July 1982. This paper describes the results obtained during the period from April 1997 to March 1998. The number of cases investigated as objectives was 215 for one year. A total of 420 strains (170 strains from primary infections and 250 strains from postoperative infections) were isolated from 174 cases (80.9% of total cases). In primary infections, the isolation rate of anaerobic bacteria was higher than in postoperative infections, while in postoperative infections, those of aerobic Gram-positive bacteria and Pseudomonas aeruginosa were higher than in primary infections. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus faecalis was the highest, followed by Staphylococcus aureus, which was frequently isolated from postoperative infections. Among anaerobic Gram-positive bacteria, Peptostreptococcus spp. and Streptococcus spp. were commonly isolated from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was most predominantly isolated from primary infections, followed by P. aeruginosa, Klebsiella pneumoniae in this order, and from postoperative infections, P. aeruginosa was most predominantly isolated, followed by E. coli and K. pneumoniae. Among anaerobic Gram-negative bacteria, Bacteroides fragilis group was the majority of isolates from both types of infections. We found neither vancomycin nor arbekacin resistant strains of S. aureus, and found no vancomycin resistant strains of Enterococcus spp. The susceptibility of P. aeruginosa against carbapenems did not decline in the year 1997, while resistance of B. fragilis group against cephems advanced increasingly.

Anti-Bacterial Agents↗
PubMed1999

Nucleocapsid formation and/or subsequent conformational change of rabies virus nucleoprotein (N) is a prerequisite step for acquiring the phosphatase-sensitive epitope of monoclonal antibody 5-2-26.

We investigated the antigenic maturation of rabies virus N protein, for which we used some conformational epitope-specific monoclonal antibodies (MAbs) and an MAb (5-2-26) against a phosphorylation-dependent linear epitope. Infected cells were lysed with a deoxycholate-free lysis buffer and separated by ultracentrifugation into the soluble top and the nucleocapsid fractions. None of the study MAbs recognized N proteins in the top fraction, whereas nucleocapsid-associated N proteins were recognized by all of the MAbs. Immunoprecipitation with polyclonal anti-N antibodies coprecipitated the P proteins from the top fraction, indicating that soluble N proteins are mostly associated with the P protein. The N proteins dissociated from both the N-P complex and nucleocapsids were recognized by none of the study MAbs, whereas the MAb 5-2-6 recognized the SDS-denatured N proteins of the nucleocapsid but not of the top fraction. In addition, the phosphorylation-deficient mutant N proteins were shown to be similarly accumulated as the wild-type N proteins into the viral inclusion bodies, defined as the virus-specific structures composed of viral nucleocapsids, that are produced in the cytoplasm of the infected cells. Based on these results, we believe that newly synthesized N proteins are not immediately phosphorylated at serine-389 (a common phosphorylation site) but are first associated with the P protein. After being used for encapsidation of the viral RNA, the N proteins undergo conformational changes, whereby epitopes for the conformation-specific MAbs are formed and become phosphorylated at serine-389.

Animals↗