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Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 1,009 records · Page 56Linked to original sources
PubMed1987

Detection of neural connection to the infundibular complex by partial or complete hypothalamic deafferentation in male quail.

To elucidate the stimulatory and inhibitory neural systems for photoperiodic control of avian reproduction, immature male Japanese quail were subjected to partial or complete hypothalamic deafferentation, followed by exposure to long and short photoperiods. The results indicated that when the encephalic photosensitive area (infundibular complex, INF) was preserved after hypothalamic deafferentation, birds were able to respond to long days and their gonads eventually recrudesced, and that testicular atrophy under short days was prevented by the semicircular cuts posterior to INF or by orbital enucleation. It is concluded that in male Japanese quail, INF plays the pivotal role in photoperiodic gonadostimulation and regulatory neurons in the retina and anterior hypothalamus may have neural connection to the posterior side of INF.

Animals↗
PubMed1987

Production of 19-hydroxy-11-deoxycorticosterone and 19-oxo-11-deoxycorticosterone from 11-deoxycorticosterone by cytochrome P-450(11)beta.

Incubation of 11-deoxycorticosterone with a cytochrome P-450(11)beta-reconstituted system yielded, in addition to corticosterone and 18-hydroxy-11-deoxycorticosterone, a new steroid product. The retention time of the new product was identical with that of authentic 19-hydroxy-11-deoxycorticosterone on high performance liquid chromatography (HPLC). The turnover number of 19-hydroxy-11-deoxycorticosterone formation was 7.0 mol/min/mol P-450. When a large amount of cytochrome P-450(11)beta was used for the reaction and the products were analyzed by HPLC, the 19-hydroxy-11-deoxycorticosterone peak disappeared from the chromatogram and concomitantly new unidentified peaks appeared. These results suggest that 19-hydroxy-11-deoxycorticosterone was further metabolized to other steroids by cytochrome P-450(11)beta. Therefore, we next incubated 19-hydroxy-11-deoxycorticosterone with cytochrome P-450(11)beta and analyzed the reaction products by HPLC. The above-mentioned unidentified peaks appeared again in the chromatogram. The retention time of one of the peaks coincided with that of authentic 19-oxo-11-deoxycorticosterone. This peak substance was purified by repeated HPLC and subjected to mass spectrometry and 1H NMR analyses. Its field desorption mass spectrum (FD-MS) showed a M+ peak at m/e 344. The 1H NMR spectrum showed the signal of an aldehyde proton instead of those of hydroxymethyl protons at the C-19 position. These results suggest that cytochrome P-450(11)beta can catalyze the 19-hydroxylation of 11-deoxycorticosterone, and the 19-hydroxy-11-deoxycorticosterone produced is further oxidized at the C-19 position to 19-oxo-11-deoxycorticosterone.

Adrenal Cortex↗
PubMed1987

Plasma progesterone profiles and embryo quality in superovulated Japanese Black cattle.

The relationship between plasma progesterone (P(4)) levels before and after superovulation treatment and embryo yield and quality was examined in Japanese Black cattle. It is concluded that a plasma P(4) level at the start of follicle stimulating hormone (FSH) injections is related to embryo quality. The P(4) level of over 3.0 ng/ml appears to be useful in preselection of donors when we want to get more than 8 normal (transferable) embryos on the average.

Journal Article↗
PubMed1987

Temperature-sensitive growth mutants as live vaccines against experimental murine salmonellosis.

Temperature-sensitive growth mutants of Salmonella enteritidis, NUB 209 and NUB 323, characterized as protein synthesis mutants, were unable to proliferate at 37 C and lost the parent's virulence. In mice, these mutants conferred high levels of protection as live vaccines. Although the vaccination effect of NUB 323 was not so good as that of NUB 209, NUB 323 was preferred as a safer live vaccine because this mutant was completely avirulent and no back mutation appeared.

Animals↗
PubMed1987

Interleukin-1 producing ability of leukaemia cells and its relationship to morphological diagnosis.

Interleukin-1 (IL-1) is a low molecular weight polypeptide produced by monocyte-macrophage lineage cells. IL-1 production by primary-cultured leukaemic cells of several FAB subtypes was estimated and compared with in vitro and in vivo lysozyme production. The results indicate that IL-1 production by monocytic leukaemia cells (M4 and M5) is significantly higher than that of myelocytic leukaemia cells (M1, M2 and M3). On the other hand, the serum lysozyme level was not correlated with the FAB subtypes and in vitro lysozyme production by monocytic leukaemia cells was higher than that of myelocytic leukaemia cells, but the M2 subtype was indistinguishable from monocytic leukaemia cells solely on the basis of lysozyme production. We concluded that measurement of IL-1 production by leukaemic cells, as a marker of monocytic leukaemias, was convenient and reliable, and might be useful for the diagnosis of morphologically or cytochemically atypical cases.

Adult↗
PubMed1987

Ossified prolactinoma: case report.

The authors report a case of ossified prolactinoma that was identified as a calcified nodule on the roentgenograms. Histologically, the ossified tissues were diffuse, and the osteoid was mineralized in various degrees, subsequently forming bones. Adenoma cells were sparse among the ossified tissues. This is probably the first report of ossified pituitary adenoma associated with osteoid metaplasia. The pathogenesis of osteoid metaplasia in pituitary adenomas is possibly due to proliferative connective tissue resulting from degeneration of the pituitary adenoma; this connective tissue may possess osteogenic potency.

Adult↗
PubMed1987

The critical period in which splenectomy causes functional disorder of the ovary in adult rats.

On account of recent reports suggesting that ovulation and luteinization involve immunological reactions, we examined the effect of splenectomy in rats on the recurrence of an estrous cycle. The spleen was removed from adult female rats at various times during an estrous cycle. A delay in ovulation was specifically induced in the rats splenectomized on the metestrous morning between 0700 and 0900 h. This delay in ovulation was reversed by an injection of splenocytes obtained either from estrous or metestrous donors, but not from diestrous or proestrous donors. The isolated splenic macrophage preparation mimicked the effect of splenocytes. Measurement of progestin levels throughout the estrous cycle suggested that the delay in ovulation was caused primarily by a delay in luteolysis; progesterone levels in ovulation delayed rats were higher and 20 alpha-dihydroprogesterone levels were lower than those of intact rats on the diestrous day. These results suggest that the macrophages in the spleen under the influence of endocrine milieu probably play a role in the recurrence of an estrous cycle by controlling luteolysis. The specific time of splenectomy to cause delay in ovulation will afford a new approach in analyzing the function of immunocytes in the ovary.

Animals↗
PubMed1987

A case of myasthenia gravis associated with thymoma, multiple schwannomas and monoclonal IgA gammopathy.

Myasthenia gravis, malignant thymoma, multiple schwannomas and monoclonal IgA gammopathy coexisted in a 54-year-old Japanese man. Serum acetylcholine receptor antibody activity was located in the IgG fraction, but not in the paraprotein peak. It was speculated that all these disorders might fall under the spectrum of the diseases associated with thymic abnormality or that some growth factors might induce neoplasms and activation of B cell clones of autoantibodies (including acetylcholine receptor antibody) in this case.

Autoantibodies↗
PubMed1987

Contribution of the mannan O side-chains to the adjuvant action of lipopolysaccharides.

Klebsiella 03 lipopolysaccharide (LPS) and Escherichia coli 09 LPS were previously shown to have potent adjuvant activities in augmenting antibody response and delayed-type hypersensitivity to protein antigens. The R form LPS extracted from the O-specific polysaccharide-less mutants derived from Klebsiella 03 and E. coli 09 strains were characterized by chemical and electrophoretic analyses. The adjuvant activities of the R-LPS in augmenting antibody response and DTH to protein antigens were much weaker than those of the parental LPS. The strength of the adjuvant activities of the R-LPS was similar to that of the activities of Salmonella minnesota LPS and Ra-LPS. By contrast, polyclonal B-cell activation effects of the R-LPS were stronger than those of the parental LPS. The common feature of the parental LPS is that their O-specific polysaccharides are mannose homopolymers (mannans). From these results, it is suggested that mannose homopolymers as the O side-chains of LPS contribute to the action of LPS in enhancing strongly the T-cell dependent immune responses to protein antigens.

Adjuvants, Immunologic↗
PubMed1987

[Significance of tumor markers in the treatment of patients with ovarian malignancies].

Seven tumor markers (CA125, CA19-9, TPA, IAP, CEA, ferritin, LDH) were measured in 24 patients with ovarian cancer. The positive rates in untreated cases of ovarian cancer were 87.5% for CA125, 35.5% for CA19-9, 10% for CEA, 77.8% for IAP, 63.6% for TPA, 28.6% for LDH and 35.3% for ferritin. Among these, CA125 was the most available marker for detecting tumor growth or regression during each respective clinical course by serial measurement. Serial changes in serum alpha-fetoprotein (AFP) levels during treatment were studied among 27 patients with ovarian embryonal carcinoma. AFP decreased with a half-life of about 7 days, and was restored to the normal range within 10 weeks after the initial surgery and chemotherapy (VAC) in all cases. In subsequently fatal cases, AFP rose again during 10 to 30 weeks after the initial treatment.

Antigens, Neoplasm↗
PubMed1987

[Gastrointestinal polyposis and hereditary large bowel cancer].

Hereditary large bowel cancer is roughly divided into the hereditary gastrointestinal polyposis (HGIP) that is including adenomatosis coli (AC), Peutz-Jeghers syndrome and juvenile polyposis, and non-polyposis familial large bowel cancer (NPF) which is including cancer family syndrome and its related conditions. In the HGIP, AC is most frequent and of highest risk of large bowel cancer, and epidemiological method of approach to patients has been well studied. NPF, however, has been insufficiently studied because of lacking of distinctive marker as seen in the polyposis in spite of that it may be actually present much more frequently than AC. In order to extract NPF from the general large bowel cancer group, the marker or criteria for it has been studied. The factors besides family history presently considered to be useful for detecting NPF are multiple cancers, proximal cancer, association of multiple adenoma and young (50 years or younger) onset of the disease.

Adenoma↗
PubMed1987

[Antitumor effects of polyamine antimetabolites with polyamine-free diet].

To evaluate the antitumor efficacy of polyamine antimetabolites such as methylglyoxal-bis-guanylhydrazone (MGBG), ethylglyoxal-bis-guanylhydrazone (EGBG), and alpha-difluoromethylornithine (DFMO), the combined therapies of polyamine antimetabolites with a polyamine-free diet were studied. The combination of EGBG plus DFMO or MGBG plus DFMO showed a marked suppression of tumor growth with a polyamine-free diet; and, when compared, EGBG was slightly superior to MGBG. The inhibition of DNA biosynthesis was also parallel to the above-mentioned results. Furthermore, from an analysis for polyamine levels in tumor tissues, it was confirmed that the polyamine depletion can be maintained by polyamine antimetabolites in combination with a polyamine-free diet in vivo. Moreover, as EGBG has lesser side effects than MGBG, EGBG might be more suitable for clinical use.

Animals↗
PubMed1987

[Antitumor efficacy of polyamine antimetabolites and mitomycin C under polyamine-free diet].

Treatment of nude mice xenografted with human gastric cancer was carried out by polyamine antimetabolites combined with mitomycin C (MMC) and polyamine-free diet. Polyamine antimetabolites, alpha-difluoromethylornithine (DFMO) and ethylglyoxal-bis-guanylhydrazone (EGBG), were given ip in a daily dose of 1,000 mg/kg and 20 mg/kg, respectively, for 6 consecutive days. MMC 2.0 mg/kg was administered every other day. The polyamine-free diet was given from 4 days before start of the treatment through the end of the study. Although the tumor growth rate of the control group given polyamine-free diet was similar to that given normal diet, in the mice treated with EGBG, DFMO plus MMC, the antitumor effect in the polyamine-free diet group was superior to the normal diet group. In comparison with tumor growth suppression due to EGBG plus DFMO or MMC only, the polyamine-free diet group showed better result than the normal diet group to some extent. In mice treated with EGBG, DFMO plus MMC, tumor tissue spermine levels in the polyamine-free diet group were significantly depressed, compared to the normal diet group. Furthermore, marked suppression of DNA biosynthesis was observed in mice given EGBG, DFMO plus MMC together with the polyamine-free diet. These results suggest that combined treatments of polyamine antimetabolites and MMC revealed a marked enhancement of antitumor effects, under conditions of polyamine depletion, which may be responsible for the alteration in DNA structure.

Animals↗
PubMed1987

[Myocardial perfusion detected using digital subtraction angiography as compared with X-ray CT and Tl-201 myocardial imaging].

Forty-two patients who underwent aorto-coronary bypass surgery were examined with intra-aortic digital subtraction angiography (IADSA) to detect abnormalities of myocardial blood perfusion. Tl-201 myocardial imaging and cardiac X-ray CT were performed nearly simultaneously about one month postoperatively. Cardiac imaging using IADSA was performed at a rate of 30 frames/sec with matrix size of 512 x 256. Time density curves of each pixel in the region of the myocardium of the left ventricle were post-processed to obtain functional images. The maximal concentration (Cmax), integration of the time-density curve (Cinteg), mean transit time (MTT), Cmax/MTT and Cinteg/MTT were computed for each pixel. Cmax and Cinteg are parameters related to the volume of the coronary vascular bed. Cmax/MTT and Cinteg/MTT are parameters related to the regional myocardial blood flow. These functional images showed hypoperfusion areas in 35 of 37 ischemic segments confirmed by wall motion in digital subtraction left ventriculography, Tl-201 myocardial imaging and ECG. Normal perfusion areas of the functional images were observed in 18 of 54 infarcted segments. These results show the complexities of myocardial perfusion in old myocardial infarction.

Coronary Angiography↗