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Biomedical subjects

M Homma

Publications and source records attributed to M Homma.

At least 127 records · Page 7Linked to original sources
PubMed1994

Clinical significance of antibodies to native or denatured 60-kd or 52-kd Ro/SS-A proteins in Sjögren's syndrome.

OBJECTIVE: To evaluate the clinical significance of antibodies to native or denatured (anti-n or anti-d) 60- or 52-kd Ro/SS-A proteins (60K or 52K) in Sjögren's syndrome (SS). METHODS: The presence of antibodies to denatured and native Ro/SS-A proteins was determined by immunoblotting and immunoprecipitation, respectively. Salivary gland dysfunction was evaluated by salivary function scintigraphy. RESULTS: The incidence of anti-d-60K without anti-d-52K was lower among patients with systemic lupus erythematosus with SS (SLE/SS) and among those with primary SS, compared with patients who had SLE without SS, whereas anti-d-52K without anti-d-60K was more common in SLE/SS patients and primary SS patients than in SLE patients without SS. All of the patients with anti-Ro/SS-A had anti-n-60K. Serologic abnormalities and salivary gland dysfunction were associated with anti-n-60K in SS, whereas Hashimoto's thyroiditis in SS was related to anti-d-60K. Anti-d-52K was not associated with any extraglandular or glandular symptoms in SS. CONCLUSION: The data indicate that anti-n-60K, which appears to recognize conformational epitopes, is associated with clinical features of SS characterized by glandular dysfunction.

Autoantibodies↗
PubMed1994

Lectin-mediated enhancement of dengue virus infection in a mouse macrophage cell line Mk1.

Treatment of a mouse macrophage cell line Mk1 with pokeweed mitogen (PWM) either before or during but not after virus inoculation resulted in an enhancement of dengue virus (DV) infection. The infection enhancement was primarily due to an increase in the number of DV-infected cells but not to increased virus production in a cell. These results suggested that PWM treatment mediated increased DV binding and/or penetration to Mk1 cells, thereby resulting in the infection enhancement. N-acetylglucosamine (GlucNAc) did not suppress PWM-mediated enhancement of DV infection when added to Mk1 cells after PWM treatment was done, although GlucNAc clearly suppressed the effect of PWM when added simultaneously with PWM. The results implied the possibility that the PWM-mediated increase in viral binding/penetration was not due to a cross-linking by PWM between DV and a cell-surface receptor, but due to another mechanism, presumably exposure of a masked DV receptor(s). The DV receptor, unidentified as yet, involved in the PWM-mediated infection enhancement appeared to have no relation with IgG Fc receptors that are known to be involved in antibody-mediated enhancement of DV infection.

Animals↗
PubMed1994

Analysis of the core and E1 envelope region sequences of a novel variant of hepatitis C virus obtained in Indonesia.

Hepatitis C virus (HCV) is currently classified into 6 major types, HCV-1 through -6, each of which can be further divided into a few subtypes, e.g., HCV-1a, -1b, -1c, etc., on the basis of sequence variation of the viral genome. The core and E1 envelope regions of HCV genome were amplified from sera of Indonesian patients using reverse transcription-polymerase chain reaction. Sequence analysis of both core and E1 regions followed by molecular evolutionary phylogenetic analysis identified a novel sequence variant of HCV-1 (Td-6). Antibodies in the serum from which Td-6 was isolated reacted only marginally to the core protein of HCV-J, a representative strain of HCV-1b, despite strong antibody response against a mixture of the core, NS3 and NS4 proteins of HCV-1a. The possible mechanism for the diminished reactivity of the antibodies in the serum to the core protein of HCV-J is discussed.

Amino Acid Sequence↗
PubMed1994

Effects of stinging nettle root extracts and their steroidal components on the Na+,K(+)-ATPase of the benign prostatic hyperplasia.

The effects of organic-solvent extracts of Urtica dioica (Urticaceae) on the Na+,K(+)-ATPase of the tissue of benign prostatic hyperplasia (BPH) were investigated. The membrane Na+,K(+)-ATPase fraction was prepared from a patient with BPH by a differential centrifugation of the tissue homogenate. The enzyme activity was inhibited by 10(-4)-10(-5) M of ouabain. The hexane extract, the ether extract, the ethyl acetate extract, and the butanol extract of the roots caused 27.6-81.5% inhibition of the enzyme activity at 0.1 mg/ml. In addition, a column extraction of stinging nettle roots using benzene as an eluent afforded efficient enzyme inhibiting activity. Steroidal components in stinging nettle roots, such as stigmast-4-en-3-one, stigmasterol, and campesterol inhibited the enzyme activity by 23.0-67.0% at concentrations ranging from 10(-3)-10(-6) M. These results suggest that some hydrophobic constituents such as steroids in the stinging nettle roots inhibited the membrane Na+,K(+)-ATPase activity of the prostate, which may subsequently suppress prostate-cell metabolism and growth.

Humans↗
PubMed1994

Increased binding activity of measles virus to monkey red blood cells after long-term passage in Vero cell cultures.

Recent field isolates of measles virus (MV) obtained by using B95-8 cells have been reported not to agglutinate African green monkey red blood cells (AGM-RBC). Vero cell-adapted, plaque-forming strains derived from three field isolates at the third passage in Vero cell cultures (T8Ve-3, T11Ve-3 and N13Ve-3) also exhibited markedly decreased binding activity, as determined by infectivity-absorption and haemadsorption tests. On the other hand, binding activity of the respective strains at the twentieth passage (T8Ve-20, T11Ve-20 and N13Ve-20) increased to practically the same level as that of the Edmonston strain, a standard strain of MV passaged long-term. A membrane immunofluorescence test revealed that the decreased binding activity to AGM-RBC of T8Ve-3, T11Ve-3 and N13Ve-3 was not due to decreased expression of the haemagglutinin (H) protein on the cell surface. The deduced amino acid sequence of the H protein synthesized in T11Ve-3-infected cells was identical to that in T11Ve-20-infected cells, although a single amino acid alteration was observed when T8Ve-3 was compared with T8Ve-20. Similarly, approximately half of the N13Ve-20-infected cells synthesized an H protein identical to that produced in N13Ve-3-infected cells, and nevertheless, exhibited markedly increased haemadsorption. The present results suggest that a viral protein(s) other than the H protein contributed to the binding activity of MV to AGM-RBC.

Amino Acid Sequence↗
PubMed1994

Electrophoretic karyotypes of Candida yeasts recurrently isolated from single patients.

Candida strains were isolated repeatedly from single patients during recurrent episodes of Candida infection in a hospital, and their electrophoretic karyotypes were analyzed by pulsed-field gel electrophoresis using CHEF system. When only C. albicans (in 6 patients) or C. glabrata (in 1 patient) were recurrently isolated, their karyotypes from each patient were almost identical to one another, suggesting that they carried single type of the yeast. When multiple species were recovered from single patients (6 cases), the karyotypes of the most frequently recovered yeast species were almost identical with respect to each patient. The electrophoretic karyotype analysis has been proved to be useful for epidemiological studies because the method can tell not only the species identification but also the differences among the strains of the same species.

Adult↗
PubMed1994

Identification of hepatitis C virus subtype 3b (HCV-3b) among Japanese patients with liver diseases using highly efficient primers for reverse transcription-polymerase chain reaction.

With a reverse transcription-polymerase chain reaction method that utilized highly efficient primers, the NS5 region of hepatitis C virus (HCV) genome could be amplified from all of the 24 serum samples randomly obtained from Japanese patients with liver diseases. Subtype analysis on the basis of nucleotide sequence similarities of the amplified fragments revealed that 2 out of 24 Japanese patients (8.3%) were infected with the recently identified subtype HCV-3b, which had been thought to be rare in Japan.

Base Sequence↗
PubMed1994

Transmembrane signalling by the chimeric chemosensory receptors of Escherichia coli Tsr and Tar with heterologous membrane-spanning regions.

The serine and aspartate chemosensory receptors (Tsr and Tar) of Escherichia coli have two membrane-spanning regions TM1 and TM2. To investigate their roles in transmembrane signalling, we constructed two chimeric receptors from Tsr and Tar with heterologous combinations of TM1 and TM2: the N-terminus of one receptor, including TM1 and the periplasmic domain, was fused to the C-terminus of the other, beginning with TM2. Both of the chimeric receptor genes rescued the chemotactic defect of a receptorless E. coli strain, indicating that the chimeric receptors are functional. Their apparent affinities for the specific ligands were the same as those of Tsr or Tar. Therefore, as far as transmembrane signalling abilities are concerned, the TM2 regions of Tsr and Tar are interchangeable, suggesting that sequence-specific interaction between TM1 and TM2 may not be required for the signal transmission across the membrane. The cells expressing either of the chimeric receptors, however, showed 'smooth', biased, basal swimming patterns. Moreover, they adapted quickly after stimulation with the repellent glycerol. This rapid adaptation was observed even in the methyltransferase-defective strain. Therefore, exchange of TM2 might impose structural constraints on the chimeric receptors that stabilize conformations which elicit smooth swimming.

Adaptation, Physiological↗
PubMed1994

A novel 11 beta-hydroxysteroid dehydrogenase inhibitor contained in saiboku-to, a herbal remedy for steroid-dependent bronchial asthma.

To identify the inhibitor of prednisolone metabolism contained in Saiboku-To, we conducted in-vitro experiments of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), using rat liver homogenate and cortisol as a typical substrate. We studied the effects of ten herbal constituents on 11 beta-HSD. Five herbal extracts showed inhibitory activity with Glycyrrhiza glabra > Perillae frutescens > Zizyphus vulgaris > Magnolia officinalis > Scutellaria baicalensis. This suggests that unknown 11 beta-HSD inhibitors are contained in four herbs other than G. glabra which contains a known inhibitor, glycyrrhizin (and glycyrrhetinic acid). Seven chemical constituents which have been identified as the major urinary products of Saiboku-To in healthy and asthmatic subjects were studied; magnolol derived from M. officinalis showed the most potent inhibition of the enzyme (IC50, 1.8 x 10(-4) M). Although this activity was less than that of glycyrrhizin, the inhibition mechanism (non-competitive) was different from a known competitive mechanism. These results suggest that magnolol might contribute to the inhibitory effects of Saiboku-To on prednisolone metabolism through inhibition of 11 beta-HSD.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1994

Diversity of tandemly repetitive sequences due to short periodic repetitions in the chromosomes of Candida albicans.

In a previous study, a repeated sequence, RPS1, was cloned from the genomic DNA of Candida albicans. It was 2.1 kb in length and was tandemly repeated in a limited region of almost all of the chromosomes. In this study, we examined and characterized the diversity of the repeating structure of the RPS units were of 2.1, 2.3, 2.5, and 2.9 kbp in length after digestion of the genomic DNA with SmaI and 2.1 and 2.3 kbp after digestion with PstI, with the differences being multiples of approximately 0.2 kbp. Moreover, one or two types of RPS unit were present specifically on each chromosome. We cloned 14 RPS units from the mixed DNA of chromosomes 1 and 2 and 59 RPS units from chromosome 6. These RPS units were classified into four types by their SfiI digestion profiles and chromosomal origins. Sequence comparisons revealed a tandem arrangement of internal, small repeating units of 172 bp. This unit of repetition was designated alt (C. albicans tandem repeating unit). The size of RPS units was variable, with sizes representing a series of increments of approximately 0.2 kbp that corresponded to the alt sequence. By contrast, the sequences other than the tandem repeats of alts were highly conserved, with homology of more than 98% among all cloned RPS units. These results suggested that RPS plays an important role in the organization and function of the chromosomes of C. albicans even though the actual function of RPS has not yet been clarified. Structural features of RPS that contains the repeated alt sequence are discussed in relation to human alpha-satellite DNA with its tandem repeats of about 170 bp that are similar in size to alt, the repetition of which is responsible for the variations in the size of the higher-order repeats.

Base Sequence↗
PubMed1994

Strain relatedness of Candida albicans strains isolated from children with leukemia and their bedside parents.

Candida yeasts are occasionally recovered from patients with leukemia in spite of antifungal therapy used during chemotherapy. It is not yet known whether yeasts in these patients are of endogenous or exogenous origin. We examined the strain relatedness of Candida albicans isolated from three patients with leukemia (A, B, and C) and their bedside parents using pulsed-field gel electrophoresis (PFGE), restriction fragment length polymorphism (RFLP) by SmaI digestion, and the Southern hybridization patterns of the RFLPs by the C. albicans-specific probe RPS1. SmaI digestion and Southern hybridization by RPS1 showed identical or similar patterns among Candida isolates in patients A and his mother, although their karyotypes were different. Isolates from patients B and both parents showed identical electrophoretic karyotypes, SmaI digestion patterns, and hybridization patterns. Since electrophoretic karyotypes are more variable than RFLPs and their hybridization patterns, the identity of the last two suggests a close relatedness between strains. Our results also suggest that transmission of yeast strains may have occurred between patient A and his mother and between patient B and her parents. Isolates from patient C and her mother are thought to have originated from different strains, since different patterns were obtained in electrophoretic karyotypes, SmaI digestion patterns, and Southern hybridization patterns.

Adult↗
PubMed1994

Analysis of hepatitis C virus isolates among healthy blood donors and drug addicts in Chiang Mai, Thailand.

Hepatitis C virus (HCV) isolates obtained from 25 anti-HCV antibody-positive healthy blood donors and 29 drug addicts in Chiang Mai, Thailand, were analyzed. HCV RNA was detected in 23 blood donor samples (92%) and 24 drug addict blood samples (83%) by PCR for a portion of the NS5 region. Subtype analysis revealed that HCV type 3a (HCV-3a) was the prevailing subtype (30%), which was followed in prevalence by HCV-1a (21%), -1b (13%), -3b (13%), and -6a (2%). Six (13%) of the 47 isolates showed low sequence similarities with known types and subtypes. The sequence variants could be grouped into four branches in a molecular evolutionary phylogenetic tree.

Amino Acid Sequence↗
PubMed1994

A protease activation mutant, MVCES1, as a safe and potent live vaccine derived from currently prevailing Sendai virus.

Sendai virus fresh isolates were shown to be antigenically different from the prototype Fushimi strain that had long been passaged in embryonated chicken eggs. Phylogenetic analysis of the hemagglutinin-neuraminidase genes also revealed the difference between these two virus groups. Both trypsin-resistant and elastase-sensitive mutations were additionally introduced to an LLC-MK2-cell-adapted and attenuated mutant derived from one of the fresh isolates. This protease activation mutant (MVCES1) showed the same antigenicity as the fresh isolates, and as a result of a single cycle of growth in lungs, it could confer better protection on mice against challenge infection with the currently prevailing Sendai virus than TR-5, which is a trypsin-resistant mutant derived from the Fushimi strain. The eligibility of MVCES1 as an attenuated live vaccine of Sendai virus is discussed.

Amino Acid Sequence↗
PubMed1994

Structural and conformational studies of [Ile7] and [Leu7]surfactins from Bacillus subtilis natto.

A novel [Ile7]surfactin (1), which showed anti-human immunodeficiency virus activity, has been isolated from Bacillus subtilis natto. Structural and conformational analysis of the peptide backbone of [Ile7]surfactin was conducted by a combination of various two-dimensional (2D) nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy and simulated annealing calculations, compared with a known [Leu7]surfactin (2). Both surfactins were shown to exist in different conformational states in both polar and apolar solvents.

Amino Acid Sequence↗
PubMed1994

[Bronchial asthma and desaturation--assessment by pulse oximetry].

In the first study, we used pulse oximetry to continuously measure SpO2 and pulse rate in inpatients with paroxysmal attacks of acute asthma. Desaturation and increases in pulse rate occurred during coughing, urination, defecation, eating, and sleeping. Desaturation was most severe and frequent when peak expiratory flow was in the red zone. When it was in the yellow zone or blue zone, desaturation was less severe and less frequent. In the second study, outpatients experiencing exacerbations of chronic asthma and inpatients experiencing acute asthmatic attacks inhaled of a beta 2-stimulant via an ultrasonic nebulizer and were monitored with pulse oximetry. In the former, SpO2 either did not change or increased, but in the latter SpO2 decreased markedly when patients were in the red zone. Therefore, when patients inhale a bronchodilator during an acute asthmatic attack they should be carefully monitored with pulse oximetry. In the third study, pulse oximetry was used to measure saturation in outpatients who were suspected of having hyperresponsive airways and had undergone an airway hyperresponsiveness test with an Astograph. Almost all of those who had desaturation of more than 4% from were markedly hyperresponsive. The degree of desaturation and the percent change in respiratory resistance were significantly correlated. In conclusion, pulse oximetry can be useful in the short-term and long-term management of asthma tic patients.

Adolescent↗
PubMed1994

Electrophoretic karyotypes of isolates of Candida albicans from hospitalized patients.

Electrophoretic karyotypes, namely, the patterns of chromosome-sized DNAs that have been separated by pulsed-field gel electrophoresis, have been reported to vary among different strains of Candida albicans, and can be useful for the delineation of strains. A previous study showed that almost all the electrophoretic karyotypes of isolates of C. albicans collected from the vagina of outpatients were distinguishable from one another. A few of the isolates had a common atypical karyotype and these isolates all had the same phenotype. This report describes the electrophoretic karyotype analysis of isolates from various specimens taken from hospitalized patients. Karyotypes were analysed with respect to the origins of the isolates in terms of two parameters: the number of bands resolved on the gel and a code of four numbers which corresponded to the number of bands that could be separated in each of four sets of chromosome sizes. No specific karyotype was correlated with either the nature of the specimen or the hospital ward to which the patient had been admitted. Most isolates gave a pattern similar to that of FC18 and no atypical karyotypes were found.

Body Fluids↗