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Biomedical subjects

R Yoshida

Publications and source records attributed to R Yoshida.

At least 109 records · Page 6Linked to original sources
PubMed1995

Trends in antimicrobial resistance of Streptococcus pneumoniae in Japan.

A total of 184 isolates of Streptococcus pneumoniae were recovered from the sputa of patients over a 5-year period in the Nagasaki area and were examined. A total of 30 strains were resistant to penicillin (MIC, > or = 0.10 micrograms/ml), 13 of which belonged to serotype 19B. These strains showed decreased susceptibility to other antimicrobial agents. Vancomycin, cefpirome, and imipenem were the most active agents tested.

Anti-Bacterial Agents↗
PubMed1995

Hypertrophic cardiomyopathy in patients with diabetes mellitus associated with mitochondrial tRNA(Leu)(UUR) gene mutation.

Left ventricular function and morphology were assessed using M-mode echocardiography in 3 patients with diabetes mellitus associated with mitochondrial tRNA(Leu)(UUR) gene mutation, who were free of clinical, electrocardiographic, or thallium scan evidence of ischemic heart disease. Echocardiograms revealed hypertrophic cardiomyopathy in all 3 patients. Hypertrophy of the interventricular septum was mild in Cases 1 and 3 (12 and 13 mm, respectively) and severe in Case 2 (22 mm) (normal 7-10 mm). When they had neither signs nor symptoms suggestive of congestive heart failure, percentage fractional shortening (%FS), an index of wall motion of the left ventricle (normal > 28%), was normal in Cases 2 and 3 (28 and 32%, respectively) whereas it was slightly decreased in Case 1 (22%). In Case 1 with mild hypertrophy, the development of congestive heart failure was associated with a marked decrease in %FS to 13%; this patient responded well to diuretics and captopril and %FS rose to 22%. However, a mild decrease in %FS to 21% caused congestive heart failure in Case 2 with severe hypertrophy. His response to treatment was marginal. The present study indicates that mitochondrial DNA analysis should be done in patients with diabetic cardiomyopathy, and that sequential echocardiography is invaluable for the detection of hypertrophic cardiomyopathy and the management of subsequent myocardial dysfunction in patients with mitochondrial diabetes mellitus and cardiomyopathy.

Adult↗
PubMed1995

[A clinical study of sudden death in the severely handicapped persons].

A clinical study was performed on 8 cases of sudden death (9.0%) selected from a series of 89 patients with severe handicaps who died at the Metropolitan Medical Center of Severely Handicapped during the period from 1968 through 1986. 1) All suffered from profound mental retardation with motor disturbance, but were able to react to environmental stimuli. 2) Most had mixed quadriplegia showing athetosis-related hypertonus. 3) Severe physical deformation and chronic respiratory symptoms were present in 6 of 8 patients. 4) Most of them were adolescent. 5) Autopsy revealed no particular findings to which the expected death could be attributed except for the right cardiac enlargement in 5 cases. Four of the 8 patients were recovering from respiratory infection or were in the process of having their anticonvulsant doses tapered. These four cases had shown recent improvement in their general systemic condition. Sudden death occurred mainly during limited time periods in the early morning or in the evening and was not related to sleep. The authors suggest that the changes in the autonomic nervous system may precipitate them into sudden death.

Adolescent↗
PubMed1995

Production of recombinant hantavirus nucleocapsid protein expressed in silkworm larvae and its use as a diagnostic antigen in detecting antibodies in serum from infected rats.

The recombinant nucleocapsid protein (rNP) of Hantaan virus was expressed by a baculovirus vector in silkworm hemolymph and was used as an antigen in western blotting (WB). The rNP is expressed in insoluble form in hemolymph; therefore simple washing of the insoluble fraction with phosphate-buffered saline by low-speed centrifugation allowed preparation of purified antigen for WB. The rNP had strain-specific and hantavirus-common epitopes similar to the authentic NP antigen of hantavirus and was stable after transfer to membrane. For detection of antibody in serially obtained sera from experimentally infected rats, WB enabled detection of IgM antibodies 3 days after infection, which was at least 2 days earlier than detection by the indirect immunofluorescent antibody test (IFA). Thus WB had a higher sensitivity than the IFA for detection of hantavirus antibody in the serum of experimentally infected rats. The WB-determined IgG antibody titer was about 10 times higher than that determined by the IFA. No background staining was observed by WB even at a 1:10 dilution of serum. The selected rat sera with strong background staining or confusing staining patterns by IFA, but not focus reduction neutralization test titers, could be interpreted as test-negative because they did not have a specific reaction to virus antigen by WB. Thus the specificity of WB was higher than that of the IFA. Moreover, WB can distinguish specific from nonspecific reactions by the detection of the specific antigen on the WB membrane. Therefore the IFA or enzyme-linked immunosorbent assay followed by WB is recommended for serologic confirmation of hantavirus infection.

Animals↗
PubMed1994

Induction in interferon-alpha/beta-treated hepatocytes of the inhibitor of the multiplication of IFN-alpha/beta-resistant Friend leukemia cells.

We reported previously that interferon-alpha/beta (IFN-alpha/beta)-treated hepatocytes in culture released a soluble factor(s) that suppressed the multiplication of an INF-alpha/beta-resistant clone of Friend leukemia cells (FLCs). To characterize the factor(s) further, we first examined the possibility that products of nonparenchymal cells (NPCs) included in small number in the hepatocyte cultures were involved in the inhibitory activity. We prepared cultures of purified adherent NPCs, mostly Kupffer cells, and sinusoidal endothelial cells, and culture supernatants of NPCs pretreated with IFN-alpha/beta were tested for the inhibitory activity for FLC multiplication. IFN did not induce any inhibitory activity in NPC cultures, whereas LPS-stimulated NPCs cultivated in parallel released several inhibitory factors including tumor necrosis factor-alpha (TNF-alpha). To explore the possibility that IFN augmented the release of hepatocyte cytosolic proteins, including arginase, we compared the inhibitory activity in culture supernatant of IFN-treated hepatocytes with that found in hepatocyte extract by anion-exchange chromatography. The IFN-induced inhibitory activity was eluted at relatively high salt concentration as a single peak, while the inhibitory activity in hepatocyte extract was co-eluted with arginase at low salt concentration. These results suggested that IFN induced production by hepatocytes of an inhibitor of FLC multiplication.

Animals↗
PubMed1994

In-vitro and in-vivo activity of a new quinolone AM-1155 against Mycoplasma pneumoniae.

We investigated the in-vitro and in-vivo activity of a new quinolone AM-1155 against Mycoplasma pneumoniae, and compared it with ofloxacin, ciprofloxacin, lomefloxacin, tosufloxacin, erythromycin and minocycline. AM-1155 was the most potent agent in vitro of the quinolones tested. Its pre-treatment minimal inhibitory concentrations for 90% of the 41 strains (MIC90) was 0.06 mg/L. In contrast, pre-treatment MIC90 values for ofloxacin, ciprofloxacin, lomefloxacin, tosufloxacin, erythromycin, and minocycline were 1, 1, 2, 0.5, 0.0156, and 0.5 mg/L, respectively. Post-treatments MIC90s, which may reflect mycoplasmacidal potency, of AM-1155, ofloxacin, ciprofloxacin, lomefloxacin, tosufloxacin, erythromycin and minocycline were 0.125, 1, 2, 4, 0.5, 0.125 and 4 mg/L, respectively. In-vitro activities of antimicrobial agents were assessed in an experimental pulmonary infection model in Syrian golden hamsters. AM-1155 was the most effective agent among five antimicrobial agents (AM-1155, ofloxacin, tosufloxacin, erythromycin, minocycline) tested in terms of reduction in viable M. pneumoniae cells and in reducing macroscopic lung lesions. These results suggest that AM-1155 will be a useful antimicrobial agent for the treatment of M. pneumoniae infections.

Animals↗
PubMed1994

In vitro and in vivo activities of sparfloxacin against Mycoplasma pneumoniae.

The in vitro and in vivo activities of sparfloxacin against Mycoplasma pneumoniae were compared with those of erythromycin, levofloxacin, ofloxacin, and minocycline. The MICs of sparfloxacin, erythromycin, levofloxacin, ofloxacin, and minocycline for 90% of the 43 M. pneumoniae strains tested were 0.063, 0.016, 0.5, 1, and 0.5 microgram/ml, respectively. In the experimental pulmonary M. pneumoniae infection model in Syrian golden hamsters, sparfloxacin was as effective as erythromycin when orally administered at 15 mg/kg twice daily for 5 days and more effective than erythromycin when orally administered at 10 mg/kg once daily for 5 days. Sparfloxacin was more effective than levofloxacin and ofloxacin in both dosing regimens. The peak concentrations of sparfloxacin in hamster sera after administration of single oral doses of 15 mg/kg were almost the same as those in human sera after administration of single oral doses of 200 mg (the usual clinical dose), and the half-life of sparfloxacin in hamster serum was shorter than that in human serum after administration of a single oral dose of 200 mg. These results suggest that sparfloxacin may be clinically useful for the treatment of M. pneumoniae infections.

Animals↗
PubMed1994

In vitro and in vivo activities of macrolides against Mycoplasma pneumoniae.

We investigated the in vitro and in vivo activities of macrolides against Mycoplasma pneumoniae. In vitro MICs of azithromycin, erythromycin, clarithromycin, and roxithromycin were determined. Azithromycin was the most potent antimicrobial agent tested in vitro. Its MIC for 90% of the strains was 0.00024 micrograms/ml. MICs for 90% of the strains of erythromycin, clarithromycin, and roxithromycin were 0.0156, 0.0078, and 0.03125 micrograms/ml, respectively. In vivo activities were assessed in a pulmonary infection model with Syrian golden hamsters. We evaluated the in vivo effects on reduction of viable M. pneumoniae cell counts and on reduction of microscopic and macroscopic histopathologies for azithromycin, erythromycin, and clarithromycin given at 10 mg/kg once daily for 1 and 3 days and given at 15 mg/kg twice daily for 2.5 and 5 days. Azithromycin was significantly more effective than erythromycin or clarithromycin in the same regimens. Especially at 10 mg/kg once daily for 1 day, only azithromycin was significantly effective in the reduction of viable M. pneumoniae cells and histopathologies. These results show that azithromycin is more efficacious than the other drugs tested against M. pneumoniae pneumonia in hamsters. These data suggest that clinical studies of macrolides in human patients are warranted.

Animals↗
PubMed1994

Modulating the phase transition temperature and thermosensitivity in N-isopropylacrylamide copolymer gels.

Temperature-responsive copolymer (or ternary copolymer) gels of N-isopropylacrylamide (IPAAm) were synthesized with hydrophobic alkyl methacrylate (RMA), hydrophilic acrylamide (AAm), N,N'-dimethylacrylamide (DMAAm), and N-acryloylpyrrolidine (APy) as comonomers. The effects of these comonomers on the phase transition temperature (LCST) and the thermosensitivity have been discussed. The LCST of poly(IPAAm) gel in phosphate buffered saline (PBS) was lowered by the introduction of hydrophobic RMA, and the change in equilibrium swelling ratio with temperature change became smaller with an increase in RMA content. However, a stable skin layer to achieve complete 'on-off' regulation of drug release was formed at a higher temperature by RMA due to hydrophobic interaction of alkyl chains. The LCST of poly(IPAAm-co-AAm) gel increased with an increase in AAm content. However, the thermosensitivity of the gel became smaller. It was suggested that hydrophilic AAm prevented the formation of a dense skin layer at a higher temperature. It was difficult to obtain a complete 'off' state due to an insufficiently dense skin layer in order to stop the drug release. The LCST was raised and great thermosensitivity was possible by the introduction of DMAAm or APy. Poly(IPAAm-co-DMAAm) enabled 'on-off' drug release in response to smaller temperature changes around the body temperature. The molecular design to control transition temperature and thermosensitivity of gel was established.

Acrylamides↗
PubMed1994

Stereotactic gamma-thalamotomy with a computerized brain atlas: technical case report.

Radiosurgical stereotactic thalamotomy was performed in a patient with parkinsonian tremor with a computerized stereotactic brain atlas, which was transformed to fit the patient's thin-sliced magnetic resonance image to select an optimal target in the nucleus ventralis intermedius of the thalamus. The patient's tremor and rigidity disappeared and have not appeared again for more than 1 year since the eighth postoperative month. A method for converting the presurgically planned stereotactic coordinates in the atlas coordinate system to the coordinates in the frame coordinate system is described.

Aged↗
PubMed1994

[A clinicopathological study of senile dementia of Alzheimer's type (SDAT) and white matter lesions of Binswanger's type].

A clinicopathological study of senile dementia of Alzheimer's type (SDAT) accompanied by the white matter lesions of Binswanger's type was carried out. Fifty-seven patients, who were diagnosed as suffering from SDAT based on clinical and pathological criteria, were classified into two groups based on the white matter lesions of Binswanger's type. Namely, group 1 consisted of the SDAT patients without any subcortical or white matter lesions (30 cases); group 2 consisted of those with white matter lesions of Binswanger's type (11 cases). The other 9 cases included those with vascular lesions and 4 with some of the same pathological changes found in Parkinson's disease. Clinically, group 2 patients showed subcortical symptoms such as urinary incontinence, Parkinsonian gait, being accompanied by hypertension and arrhythmias. Periventricular lucency (CT) were common in group 2. Macroscopically, both groups showed moderately to severe atrophy, and the width of the corpus callosum of group 2 was narrower than that of group 1. There was no difference in cerebral arteriosclerosis between the groups. In microscopic findings, patients in group 2 showed diffuse distribution of cortical changes such as senile plaques as well as Alzheimer's senile plaques as well as Alzheimer's neurofibrillary tangles while those in group 1 showed various types of diffuse or local distribution. Arteriolosclerosis of the white matter were found in both groups. There was no difference in aortic atherosclerosis and/or heart disease. The complication of white matter lesions of Binswanger's type was not a rare finding in SDAT.

Aged↗
PubMed1994

[Virulence factors of drug resistant strain].

The incidence of methicillin resistant Staphylococcus aureus and penicillin resistant Streptococcus pneumoniae have been increasing in Japan. These resistant strains produce toxins and extracellular enzymes working as virulence factors of infection. Some of these toxins and extracellular enzymes are introduced here. The difference of virulence between MRSA and MSSA is not clear but some of MRSA strains are known to produce new type cytotoxins. The difference of virulence factors between penicillin resistant S. pneumoniae and penicillin sensitive S. pneumoniae were not observed.

Cytotoxins↗
PubMed1994

[A case of oligomeganephronia--quantitative measurement of the glomerular surface area and the number of glomeruli with a color image analyzer].

We report here a nine-year-old boy with oligomeganephronia. The patient had proteinuria and morphometric analysis of the renal biopsy specimen confirmed the diagnosis of oligomeganephronia. We employed a color image analyzer (OLYMPUS Corp.) to determine the glomerular surface area and the number of glomeruli per mm2 of the renal cortex of the patient. All the scanned glomeruli showed marked hypertrophy; the mean maximal surface area for the 5 glomeruli was 46 x 10(3) microns 2, which is approximately 4 times larger than that of normal children of the same age. The number of glomeruli per mm2 of the renal cortex of the patient had decreased to 1. 11 per mm2, which is approximately one fourth that of normal controls with IgA glomerulonephritis. The color image analyzer proved to be useful for the diagnosis of oligomeganephronia enabling the quantitative measurement of the glomerular surface area and the number of glomeruli per mm2 of the renal cortex.

Child↗
PubMed1993

Synergism between IFN-gamma and IL-1 alpha/beta in growth inhibition of an allografted tumor.

Soluble effector molecules involved in the rejection of allografted mouse Meth A (3-methylcholanthrene-induced ascites type tumor) cells were examined. A potent antiproliferative activity against the tumor cells was detected in the culture supernatant of leukocytes that had infiltrated into the peritoneal cavity of C57BL/6 mice on days 6-8 after transplantation, when the i.p. transplanted Meth A cells were undergoing rejection. Studies with neutralizing antibodies indicated that both IFN-gamma and IL-1 alpha/beta were required for the activity but that TNF-alpha was not. Actually, mouse rIFN-gamma and rIL-1 alpha/beta used, at the concentrations found in the culture supernatant determined by ELISA, were able to reconstitute the potent antiproliferative activity, although each cytokine alone had a weak growth inhibitory activity against Meth A cells. The half-maximal inhibition was observed with 0.02-0.03 U/ml of rIL-1 alpha/beta at 1-100 U/ml of rIFN-gamma. The synergistic growth inhibitory effect of these cytokines also was observed with four of 15 mouse transformed cell lines tested, indicating that the effect was not specific to Meth A cells. These findings suggest that IFN-gamma and IL-1 alpha/beta participate as soluble effector molecules in the rejection of some allografted tumor cells including Meth A cells.

Animals↗
PubMed1993

Protective immunity of Hantaan virus nucleocapsid and envelope protein studied using baculovirus-expressed proteins.

Recombinant Hantaan virus nucleocapsid protein (rNP) and recombinant envelope (rEnv) proteins were prepared using a baculovirus expression system to examine the role of Hantaan virus structural proteins in protective immunity. Passive transfer of spleen cells from mice immunized with rNP conferred partial protection or prolongation of time to death from fatal Hantaan virus infection in suckling mice which were challenged with Hantaan virus at 40 LD50 (survival rate: 43%) or 4 LD50 (survival rate: 43%). The T cell-enriched fraction protected one mouse from lethal infection but the B cell-enriched fraction had no such effect on fatal HTN infection. The protective effects of the antibody against HTN challenge were examined by passive immunization. The monoclonal antibody ECO 2 directed to NP also conferred partial survival and significant difference in time to death. Although rEnv antigen failed to induce neutralizing antibody, both immune spleen cells and immune serum to rEnv conferred partial protection upon suckling mice. These results indicate that both nucleocapsid and envelope proteins of Hantaan virus were responsible for induction of cell mediated protective immunity. Vero E 6 cells infected with Hantaan virus expressed envelope protein on the surface, as determined by flow cytometry. However, there was only negligible expression of nucleocapsid protein.

Animals↗
PubMed1993

The Costello syndrome: are nasal papillomata essential?

Two patients with the Costello syndrome are presented. One was a 7-year-old girl with a history of infantile hypotonia and feeding difficulties. The other was a 3 5/12-year-old boy with a history of neonatal sepsis and respiratory problems. Both had relative macrocephaly at birth, curly hair, large ear lobes, epicanthic folds, a low nasal bridge, thick lips, a short and wide nose, a short neck, a barrel chest, redundant skin, tight Achilles tendons, and pes equinovarus. Nasal papillomata, as described in Costello's two patients, were absent in both patients. Borochowitz et al. (1992) described five patients with what we interpreted as the Costello syndrome but without nasal papillomata. In view of these findings, nasal papillomata are not likely to be essential in the diagnosis of the Costello syndrome.

Abnormalities, Multiple↗