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Biomedical subjects

M Mizuno

Publications and source records attributed to M Mizuno.

At least 649 records · Page 36Linked to original sources

The use of pulmonary scintigraphy for endobronchial foreign bodies.

Pulmonary scintigraphy using 99mTc-MAA clearly demonstrated a perfusion defect in the entire left lung of an 11-month-old girl with endobronchial foreign body. Other initial examinations, including a chest roentgenogram, showed only minimal changes. Repeated pulmonary scintigraphy 24 hr after endoscopic removal of a peanut fragment from the left main stem bronchus demonstrated almost normal blood flow in the left lung. The well-known physiological explanation for diminished pulmonary blood flow due to endobronchial foreign bodies is as follows; alveolar hypoxia caused by hypoventilation due to bronchial check-valve obstruction leads to a pulmonary vasoconstriction with resultant diminution of the regional perfusion. Furthermore, the increase in alveolar pressure caused by bronchial check-valve obstruction may play a significant role in decreased pulmonary blood flow.

Arachis↗

Genetic resistance in Japanese wild mice (Mus musculus molossinus) to an NB-tropic Friend murine leukemia virus.

Wild mice (Sk, Hz-Vl, Hz-IV Om, Mol.A, Fu, Te, and Sn) trapped in various areas of Japan were crossed with mice of inbred strains (C57BL/6, C57L, BALB/c, and C57BL/10), and their progeny were infected with NB-tropic Friend nurine leukemia virus. Ten days after infection, the spleens were weighed, examined for macroscopic focal lesions, and assayed for infectious virus by the XC test. Genetic analysis indicated that 4 of 8 mice tested had a dominant gene that suppresses the virus replication; the gene resembles the Fv-4' allele. No mice with the Fv-2' allele were found.

Animals↗

[Survey of marker genes in the 9 rat strains (author's transl)].

In total of 17 genetic traits of the 9 strains of rats, Rattus norvegicus, examined, 9 loci showed polymorphic, being a, c, d, h, Es-1, Es-2, Es-3, Amy-1 and sex-influenced esterase (d-allele is not identified [12]. These genetic markers are not only useful as linkage markers but also available for inspection of proper maintenance of inbred rat strains.

Animals↗

Thyroid function in molar pregnancy.

Various aspects of thyroid hormone economy were examined in 15 patients with molar pregnancy and in 5 patients with choriocarcinoma. None of the patients with molar pregnancy was clinically thyrotoxic, though serum thyroxine (T4) was increased in 13 and free T4 concentrations were above normal in four of ten in whom measurements were made. In 2 patients with elevated serum T4 levels and in one patient with normal serum T4 levels, the daily rate of T4 disposal was increase, and most of 131I derived from 131I-T4 was excreted into urine in two patients in whom estimation of urinary excretion was made. Serum total triiodothyronine (T3) concentrations closely paralleled those of serum T4, but T3/T4 ratios were lower than those previously found in patients with toxic diffuse goiter of Graves' disease. Unresponsiveness to exogenous thyrotropin-releasing hormone (TRH) was observed in 5 patients with molar pregnancy whose serum total T4 and T3 levels were increased. Human chorionic gonadotropin (hCG) concentrations in serum ranged from 0.5 to 2830 IU/ml and were less than 200 IU/ml in 36% of the patients, possibly because molar pregnancy was diagnosed by ultrasonography, rather than high titers of urinary or serum hCG. Serum thyroid stimulating activity measured by the McKenzie bioassay closely paralleled values for hCG (r:+0.94). All thyroid abnormalities disappeared quickly after removal of the mole. In choriocarcinoma, no abnormality of thyroid function was found. These results suggest that: 1) some patients with molar pregnancy display a marked elevation of serum T4, T3, and free T4 concentrations, probably as a result of the action of a thyroid stimulator which is closely related to serum hCG or may be hCG itself; 2) T4 production rates are increased in these patients, and the pituitary responds to TRH in a manner similar to that found in thyrotoxicosis. Despite this, frank clinical thyrotoxicosis is usually absent, possibly because of relatively low serum T3/T4 ratios, possibly because of the limited duration of thyroid hyperfunction, and possibly because of other factors that for the present remain unknown.

Adult↗

[Importance of biochemical marker genes in inbred strains of mice. Some problems on checking genetic purity of inbred strains (author's transl)].

In order to check genetic purity of inbred strains of mice, we surveyed five biochemical variants in certain 69 strains, some of which had established from Japanese fancy mice. The loci examined were Hemoglobin beta-chain, Malic enzyme (supernatant form), Isocitrate dehydrogenase (supernatant form), Serum esterase-1, and Serum esterase-2. These loci were all in homozygous states as far as examined, however some subline divergences were found in a few strains, that is to say, sublines were found to be fixed with different alleles as some loci, Important of biochemical marker genes to check genetic purity of strains and several derived problems are mentioned.

Animals↗

Measurements of free thyroxine: comparison of per cent of free thyroxine in diluted and undiluted sera.

The effect of dilution on values of the per cent of free T4 in serum (%FT4) measured by equilibrium dialysis, was determined by comparing the values for %FT4 in diluted and undiluted specimens. The specimens studied were sera obtained from 10 normal subjects, 10 patients with hyperthyroidism, 5 with hypothyroidism, and 9 women with normal pregnancy. The method of analysis employed was that described by Sterling and Brenner, except that the 125I-thyroxine used was predialyzed to remove non-thyroxine contaminants and that "corrected" values for %FT4 were calculated by dividing measured values by the numerical extent to which the serum had been diluted.

Female↗

[Occurrence of the heterozygosity at Es-1 locus in a sub-strain of the NZB mice].

In the course of inspection of the biochemical marker genes in inbred strains of mice maintained in our laboratory, a female mouse of the NZB strain was found to be heterozygous for the Es-1 locus. Namely, it was Es-1a/Es-1b type. After this finding, many heterozygous mice were found among her sisters and the descendants. However, these heterozygotes (Es-1a/Es-1b) showed no heterozygosity for other 11 characters, i.e., the 6 biochemical markers (Hbb, Trf, Es-2, Id-1, Mod-1, Gpd-1) and the 5 coat colour markers (A, B, C, D, AND S) were idential as those previously described. It was, moreover, observed that they possessed the immunological characteristics typical of the NZB mice. Therefore, it could be concluded that the heterozygosity had been originated from a single mutation at the Es-1 locus, i.e., from Es-1a to Es-1b or vice versa. With regard to the alleles at the Es-1 locus, an investigation was carried out in two sub-strains of the NZB mice having different breeding history and the followings were clarified. One substrain imported from Karolinska Institute, Sweden, had been fixed with the Es-1a allele and the other imported from England was found to be Es-1b/Es-1b type. The NZB mice which displayed the heterozygosity had been derieved from the Karolinska sub-strain. Importance of biochemical marker genes for inspection of proper maintenance of inbred strains has been discussed.

Animals↗

Effect of methionine on cephalosporin C and penicillin N production by a mutant of Cephalosporium acremonium.

A mutant with enhanced potential to utilize sulfate for cephalosporin C production was isolated from a strain of Cephalosporium acremonium. The mutant displayed potency levels more than twofold that of the parent in the presence of sulfate but its productivity was severely inhibited by more than 0.5% of methionine which gave high cephalosporin C production with the parent. In a complex medium norleucine stimulated cephalosporin C production by the mutant in the presence of sulfate, whereas it showed no effect on the parent. In an incubation system with sulfur-starved cells of the mutant, L-methionine, but not the D-isomer, gave lower cephalosporin C production and a delayed production of penicillin N. However, it exhibited a stimulatory effect in the presence of valine or alpha-aminoadipic acid, the constituent amino acids of the antibiotic. Norleucine showed a similar effect to that of L-methionine in the presence of sulfate. On the basis of these results, characteristics of the mutant are discussed in connection with the effect of methionine.

2-Aminoadipic Acid↗