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Biomedical subjects

M Ogata

Publications and source records attributed to M Ogata.

At least 271 records · Page 15Linked to original sources
PubMed1991

Compensatory process of vestibular neuronitis. From findings of combined galvanic test and caloric test.

The compensatory process of vestibular neuronitis in 7 patients was followed up and evaluated using the Combined Galvanic Test (CGT) and other neuro-otological data. CGT is the simultaneous recording of both galvanic eye movement (GEM) and galvanic body sway (GBS), and has proved to be reliable in the diagnosis of retrolabyrinthine disorders. The results were as follows: The subjective symptoms remained in 3 cases from 1 month to 1 year. The recovery of the GBS response was seen earlier than that of both GEM and caloric responses. The recovery of GEM and caloric responses was observed at almost the same time. We observed the favorable recovery process of caloric response and GEM response in some cases which had recovery of GBS response within 4 weeks and suggest that the system of GBS response is different from that of GEM and caloric response. However, the systems of the latter two may be the same. We assume that the recovery of GBS response is earlier than that of GEM and caloric responses because the otolithic system recovers more easily than the semicircular canal system. The CGT and caloric test were reliable in examining the compensatory process of vestibular neuronitis.

Adult↗
PubMed1991

Partial sequences of high-molecular-weight cytochrome c isolated from Desulfovibrio vulgaris Miyazaki.

A polyhemic high-molecular-weight cytochrome c (hmc) of Mr 67,000 was purified from Desulfovibrio vulgaris Miyazaki. This cytochrome is composed of a single peptide chain. Unlike other c-type cytochromes, hmc deteriorates slowly in atmospheric oxygen. Two peptide fragments of Mr 33,100 (L peptide) and Mr 19,100 (S peptide) were isolated and their N-terminal sequences determined to be PLPGATGEQRADLVEIGVMAKFTNLELPKV (L peptide) and GTLPAVAIPEFVTIGVLK (S peptide). The established sequence of the L peptide is homologous to the N-terminal sequence of cytochrome c3 (Mr 26,000) from D. vulgaris Hildenborough, in spite of discrepancies observed in the molecular size and subunit structure of these cytochromes.

Amino Acid Sequence↗
PubMed1991

Exhalation of metallic mercury by acatalasemic, hypocatalasemic and normal mice exposed to metallic mercury vapor.

In order to elucidate the amounts of metallic mercury exhaled from mice having different amounts of catalase activity, normal, homozygous hypocatalasemic and acatalasemic mice were exposed to radioactive metallic mercury vapor at three levels of concentrations (0.072, 0.144, and 0.297 mg/m3). The timed and cumulative amounts of metallic mercury exhaled from the mice were used to classify them, in the descending order, as being acatalasemic, hypocatalasemic, and normal at the three environmental mercury concentrations. The statistical differences in the mean values among the acatalasemic, hypocatalasemic, and normal mice were calculated by the use of one-way ANOVA and multiple comparison of the mean values by Tukey's method. The mean values of the timed amounts of exhaled metallic mercury were found to be significantly different (P less than 0.05) among the three kinds of mice several hours after exposure, and those of the cumulative amounts of exhaled metallic mercury were in the descending order of acatalasemic, hypocatalasemic and normal mice, and were significantly different among the three types of mice almost over the entire time course. Thus, negative correlation coefficients were obtained between the logarithms of the catalase activity in the lungs and the blood, and the logarithms of the cumulative amounts of exhaled metallic mercury.

Acatalasia↗
PubMed1991

[Antibody responses in human being to pre-S2 and related hepatitis B virus-envelope antigens in vivo and in vitro].

Although hepatitis B (HB) virus-associated pre-S2 Ag may be important in facilitating the uptake of virions into hepatocytes, it is not clear whether the anti-pre-S2 antibody plays a substantial role in the protection from infection in man. The mechanisms underlying the nonresponsiveness to the HB vaccine are not clear. To evaluate the immunological background in nonresponders to pre-S2 Ag, HLA-DR/DQ antigens and the production of antibodies to pre-S2 Ag and HBs Ag were estimated in vitro on medical healthy personnel. Ninety-one males and 213 females were vaccinated with pre-S2 Ag positive plasma-derived HB vaccine three times. Four months after the third vaccination, blood was withdrawn for pre-S2 antibody test by ELISA. Antibodies to pre-S2 Ag were found in 19.8% of the individuals. Nonresponders were observed at a higher frequency in males than females, and they were seen more frequently in the elderly than young individuals. In aged subjects, aging seemed to be the major factor in their unresponsiveness. A high frequency of HLA-DR4.DRw53.DQw3 haplotype was observed in the subjects with nonresponsiveness against pre-S2 Ag. In order to induce the secretion of anti-HBs antibody, we investigated the effect of simultaneous administration of HBs Ag and immunoglobulin containing anti-HBs antibody on the antibody responses in vitro. In vitro stimulation of mononuclear cells from 10 individuals who failed to respond or responded poorly to HB vaccine induced a significant amount of anti-HBs antibody in 5 cases, whereas stimulation with HBs Ag alone failed to induce the antibody secretion in most cases.

Adult↗
PubMed1991

Demonstration of hemoglobin in the kidney of battered children.

We examined specimens of renal tissue taken from 40 cadavers of children (18 battered and 22 non-battered children) by an immuno-peroxidase technique using anti-human hemoglobin (Hb) or anti-human myoglobin (Mb) antiserum. Hb was detected in the proximal tubular cells of the kidney of six battered children who had sustained severe or moderate external injuries, whereas Mb was not found. In contrast, Mb was detected and Hb was not found in the renal tubules of one child who had died from a traffic accident. In other cases including 13 cases of children who died from a sudden bout of physical violence or some other impulsive act and 4 cases of children who had died from malnutrition, neither Hb nor Mb was found in the kidney. Our findings appear to indicate that large quantities of Hb were released from the multiple lesions of the battered children, entered the circulation and were deposited in the kidneys. It thus seems that the immunohistochemical detection of Hb in the kidney may be useful for evidencing the extensive antemortem bruises which are often found in battered children.

Adolescent↗
PubMed1990

Processing of Pseudomonas exotoxin by a cellular protease results in the generation of a 37,000-Da toxin fragment that is translocated to the cytosol.

Pseudomonas exotoxin (PE) was incubated with cells and extracts analyzed for processed fragments. PE was proteolytically cleaved to produce a N-terminal 28-kDa and a C-terminal 37-kDa fragment, the latter being composed of a portion of domain II and all of domain III (the ADP-ribosylating domain). Cleavage was evident at 10 min after toxin addition and endosome preparations contained the processed fragments. Initially, the two fragments were linked by a disulfide bond. Subsequently, the 37-kDa fragment was reduced and translocated to the cytosol where it inactivated protein synthesis. Cytosol from toxin-treated cells was greatly enriched in the 37-kDa fragment. The 37-kDa fragment appears to be essential for toxicity since mutant PE molecules that do not produce this fragment, or cannot deliver it to the cytosol, fail to kill cells.

ADP Ribose Transferases↗
PubMed1990

Cloned origin of DNA replication in c-myc gene can function and be transmitted in transgenic mice in an episomal state.

The c-myc protein has recently been shown to interact with a region possessing putative origin of DNA replication and enhancer activities located 2 kb upstream of the c-myc gene itself. Transgenic mice were obtained by injecting constructs containing this region, termed pmyc(H-P), into fertilized mouse eggs. The transgenic elements were capable of efficient replication in all mouse tissues examined and were maintained in an episomal state even in highly differentiated cells. Moreover, pmyc(H-P) was transmittable to the progeny throughout several generations, which suggests that the fragment derived from the region upstream of the c-myc gene possesses sequences necessary for partition, stability and DNA replication of the plasmid in the cells. In addition, we have shown that the plasmid might be captured only by eggs, not by sperm.

Animals↗
PubMed1990

An in vitro model for cyclosporin A-induced interference of intrathymic clonal elimination.

The effects of cyclosporin A (CsA) on influencing the intrathymic clonal deletion were investigated by using our established thymic stromal cell clone with capacities to express Ia antigens and to produce a unique T cell growth factor. The following were revealed: (a) T cell clone with a given specificity was killed on the Ia+ stromal cell monolayer in the presence of the relevant antigens, a process depending on T cell receptor (TCR) stimulation; and (b) CsA allowed the T cell clone to continuously proliferate even during TCR stimulation by virtue of the stromal cell-derived T cell growth factor. This paper describes an in vitro model of a mechanism by which CsA is responsible for the generation of normally "forbidden" T cell clones.

Animals↗
PubMed1990

Decreased coronary vasodilatory capacity in hypertrophic cardiomyopathy determined by split-dose thallium-dipyridamole myocardial scintigraphy.

Split-dose thallium-dipyridamole myocardial scintigraphy was performed in patients with nonobstructive hypertrophic cardiomyopathy (HC) who had angiographically normal coronary arteries. The dipyridamole-induced increases in thallium-201 uptake, calculated to evaluate coronary vasodilatory capacity, were significantly lower in 30 patients with HC than in 13 control subjects (177 +/- 58 vs 281 +/- 46%) and the reductions were observed in both the septal and lateral segments. The reductions of the septal segment in HC patients were significantly greater than those in 10 hypertensive patients with comparable degrees of septal hypertrophy. Of patients with HC, 16 had increases in thallium uptake well below the normal range. Compared with those having normal increases, these patients had significantly lower exercise duration (11 vs 15 minutes), with 33% having ST depression develop at a workload less than or equal to 80 watts. These data indicate that approximately one-half of patients with HC have impaired coronary vasodilatory capacity that could be an important pathophysiologic abnormality of HC resulting in the development of myocardial ischemia and the impairment of cardiac performance during exercise.

Adolescent↗
PubMed1990

Molecular analysis of human acatalasemia. Identification of a splicing mutation.

To search for the molecular defect of Japanese-type acatalasemia, we cloned the mutant catalase gene from a person with this deficiency. The nucleotide sequence of the mutant gene was determined for all exons, exon/intron junctions, and 5' and 3' flanking regions, and the findings were compared with the sequence from the normal gene. Seven base differences were found between the two genes. Among them, a G to A substitution at the fifth position of intron 4 (a splicing mutation) seemed most likely to be responsible for the defective catalase synthesis in the subject. To obtain suggestive evidence, we constructed chimeric genes that contained a segment of either the normal or mutant catalase gene, encompassing a 3' part of exon 4, the entire intron 4 and a 5' portion of exon 5, within the third exon of the human alpha-globin gene. When this chimeric gene construct was introduced into simian virus 40-transformed simian cells (COS-7), the transcript of the normal catalase/alpha-globin chimeric gene was spliced correctly, as revealed by Northern blotting and RNase mapping techniques. In contrast, the splicing of the mutant chimeric pre-mRNA occurred between the 5' donor site of the preceding intron and the 3' acceptor site of the intron containing the substitution, thereby skipping one entire exon sequence. Thus, the G to A transition at the fifth position of intron 4 of the catalase gene indeed severely limits the correct splicing of the RNA product. The same splice site mutation was found in the genomic DNA of another acatalasemic individual from an unrelated family. We suggest that this base substitution is the causal mutation of these cases of Japanese-type acatalasemia.

Acatalasia↗
PubMed1990

Thymic stroma-derived T cell growth factor (TSTGF): III. Its ability to promote T cell proliferation without stimulating interleukin 2- or 4-dependent autocrine mechanism.

A thymic stroma-derived cell clone, MRL104.8a produced a T cell growth factor designated as thymic stroma-derived T cell growth factor (TSTGF). This factor that is distinct from previously described T cell growth factors such as interleukin (IL) 2 or 4 was capable of promoting the growth of IL2-dependent, antigen-specific helper T cell clones. While such growth promotion was induced without requirement of the relevant antigen and exogenous IL2, we further investigated whether it depended on activation of an IL2- or IL4-dependent autocrine mechanism. Helper T cell clones, 8-E and 8-5, were able to proliferate in response to stimulation with either antigen or TSTGF. 8-E and 8-5 produced IL2 and IL4, respectively, in cultures following antigenic stimulation, whereas neither IL2 nor IL4 activity was detected in cultures during TSTGF-induced proliferation. The proliferation of these helper T cell clones by antigenic stimulation was almost completely inhibited when anti-IL2 receptor or anti-IL4 antibody was added to the cultures. The addition of cyclosporin A (CsA) to cultures of 8-E and 8-5 clones together with antigen also resulted in the complete inhibition of cellular proliferation in association with the suppression of IL2 and IL4 production. In contrast, TSTGF-induced proliferation was not affected by addition of either type of antibody or CsA. These results indicate that TSTGF is a novel T cell growth factor that can exert its own growth-promoting effect without depending on an IL2- or IL4-operating autocrine mechanism.

Animals↗
PubMed1990

Enzymatic assay of formic acid and gas chromatography of methanol for urinary biological monitoring of exposure to methanol.

An enzymatic assay method for the determination of urinary formic acid is described. Formic acid in urine was cleaved to carbon dioxide and water by formic acid dehydrogenase, whereby NAD+ was converted to NADH, which reacted with INT (p-iodonitrotetrazolium violet) in the presence of NAD-diaphorase. The color thus produced was determined at 500 nm. In addition, a simple gas chromatographic method of urinary formic acid is described, in which head space gas of formic acid methylester was applied into the wide bore column. The urinary formic acid concentrations by the enzymatic method agreed well with that by the gas chromatographic method. A simple gas chromatographic method for urinary methanol assay is also described. Acetonitrile was added to an equal volume of urine containing methanol. After centrifugation, the supernatant was injected into gas chromatography (GC). The peaks of urinary methanol and ethanol were separated by GC. Formic acid and methanol in urine of unexposed healthy subjects and workers exposed to methanol were analyzed by the colorimetric and gas chromatographic methods. Geometric mean concentrations of urinary formic acid and methanol in the healthy subjects were 7.82 mg/g creatinine and 1.34 mg/l, respectively. The concentration ratio of formic acid to methanol in the urine of the workers exposed to methanol was calculated to be 3.67 +/- 2.10, which agreed with the ratio under a controlled exposure experiment. A slower excretion of formic acid than that of methanol in the urine of a volunteer was also observed.

Adult↗
PubMed1990

Quantitative and qualitative analysis of DNA extracted from postmortem muscle tissues.

DNA extracted from 33 postmortem muscle specimens was analyzed using MZ 1.3, a hypervariable minisatellite probe, as well as locus-specific minisatellite probes (g3, MS1 and MS43). After storage at -25 degrees C for 10 months, DNA from all the samples was partially (approximately 21% of total DNA) degraded even when autopsy was performed 1 day postmortem. However, more than 90% of DNA samples up to at least 3 days postmortem were suitable to obtain good restriction fragment length polymorphism (RFLP) patterns. When small strips of specimen were stored for 8 days at room temperature in moist chambers, approximately 42% of total DNA was degraded. Only 30% of these DNA samples still showed good RFLP patterns. However, no obvious relation between qualities of DNA analyzed by detection of RFLP and quantities of total and high-MW DNA became apparent. A case of familial relationship was ascertained by DNA fingerprints. Since DNA of good quality can be recovered from muscle tissues in large quantities, DNA extraction from muscle tissues and detection of RFLP patterns should be very useful for individual identification in autopsy cases.

Accidents, Aviation↗
PubMed1990

The changes in arterial keton bodies during upper abdominal surgery.

The relationship between the arterial keton body ratio (AKBR: acetoacetate/Beta-hydroxybutyrate) and the plasma hormone activities were studied under a general anesthesia using enflurane group (group G) and a GO + Epidural group (group E) with continuous glucose loading (10 g.hr(-1)) during partial gastrectomy. In both groups, the AKBR increased significantly during the operation. The plasma insulin activity was significantly positively correlated with the AKBR and it was negatively correlated with log (Beta-hydroxybutyrate) in both groups. We could not find any significant difference of the AKBR between group G and group E. Our results indicate that the plasma insulin activity affects the arterial keton body ratio and that the AKBR must be evaluated considering the plasma hormone activity, especially insulin activity during the operation.

Journal Article↗
PubMed1990

Hepatic and muscle injuries in mice treated with heptachlor.

Heptachlor is a major component of the insecticide, chlordane. It is a health hazard but is still in use in some countries of Southeast Asia. To elucidate the toxicity of heptachlor its effects on mice after oral and intraperitoneal administration were studied. A 3-day group, 92-day group and 180-day group were given heptachlor intraperitoneally, orally and ad libitum, respectively. Results showed increased levels of serum alanine aminotransferase and decreased levels of serum cholinesterase activity. Serum creatine phosphokinase levels increased significantly. These may be due to the disruption of muscle membrane by chlordane. Results also showed significant variations of serum lipid levels from control as heptachlor has a known effect on lipid metabolism. Also the lipid peroxide levels expressed as TBA values were increased significantly, showing heptachlor's role in causing liver injury. These results suggest that the deterioration of membranes due to lipid peroxidation leads to liver and muscle injuries caused by heptachlor.

Alanine Transaminase↗
PubMed1990

Differentiation of thymocytes from CD3-CD4-CD8- through CD3-CD4-CD8+ into more mature stages induced by a thymic stromal cell clone.

We have investigated the capacity of our established thymic stromal cell clone (MRL104.8a) or its derived factor(s) to induce the differentiation of immature thymocytes. Culture of purified adult murine double-negative (CD4-CD8-, indicated here as CD4-8-) thymocytes on the MRL104.8a thymic stromal cell monolayer for 1 day resulted in the induction of an appreciable percentage of CD4-8+ thymocytes. A bone marrow-derived stromal cell monolayer or a L929 fibroblast monolayer failed to generate CD4-8+ cells. This differentiation could also be induced by a semipurified sample of the MRL104.8a culture supernatant, which contained a thymic stroma-derived T-cell growth factor capable of contributing to the growth of double-negative immature thymocytes. CD4-8+ thymocytes generated 1 day after coculture with the MRL104.8a cells or the sample containing thymic stroma-derived T-cell growth factor were found to be CD3- and J11d+, excluding the possibility of expansion of mature (CD3+4-8+) thymocytes present in the thymus. More importantly, when the culture period was extended to 2 or 3 days, an appreciable number of CD4+8+ and single-positive (CD4+) cells were generated on the MRL104.8a monolayer. Thus, these results provide the direct demonstration that CD3-4-8- immature thymocytes are promoted to differentiate through a rapidly cycling intermediate (CD3-4-8+) into double- and single-positive cells by a specialized thymic stromal component.

Animals↗