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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 1,135 records · Page 63Linked to original sources
PubMed1992

Modulation of mouse placental lactogen-I secretion in vitro: effects of progesterone and mouse placental lactogen-II.

The primary objective of this study was to develop a cell culture system for assessing effects of putative secretagogues on mouse PL-I (mPL-I) secretion. Trophoblast from days 7 to 11 of pregnancy was dispersed in collagenase, and the cells were fractionated on a Percoll gradient and plated on collagen gels in serum-free medium. Cells from days 7-9 of pregnancy yielded five bands on Percoll gradients and those from days 10 and 11 yielded six. mPL-I was present in four of the bands of cells from each day of pregnancy. Cells from day 7 of pregnancy that banded at a density of 1.044 g/ml secreted the largest amount of mPL-I during 5 days of culture. The mPL-I concentration of the medium of these cells increased for the first 3 or 4 days of culture and then declined on the fifth day. mPL-II could not be detected in the medium until the third or fourth day of culture, and its concentration increased thereafter. Cell viability was about 90% at the time of plating, remained at about 80% between days 1 and 4, and then declined on day 5. The cell type that produced mPL-I was identified with the reverse hemolytic plaque assay and by staining with anti-mPL-I antiserum. Both methods indicated that mPL-I was produced by giant cells. The ability of the cells to respond to putative secretagogues was examined using mPL-II and progesterone. mPL-II, at concentrations ranging between 10 ng/ml and 10 micrograms/ml, had no effect on the mPL-I concentration of the medium when it was present for up to 3 days of culture, which suggests that mPL-II does not inhibit mPL-I secretion in vitro. Incubation of the cells in the presence of 100-1000 ng/ml progesterone caused a dose- and time-dependent reduction in the mPL-I concentration of the medium and a decrease in the number of cells that stained with anti-mPL-I antiserum. The effect of progesterone on both endpoints was not apparent until the second day of treatment. These data suggest that progesterone inhibits mPL-I secretion at least in part by inhibiting the differentiation of mPL-I-producing giant cells. The fact that the mPL-I-producing cells responded to progesterone indicates that this culture system will be useful in assessing effects of putative secretagogues on mPL-I secretion.

Animals↗
PubMed1992

Production of mouse placental lactogen-I and placental lactogen-II by the same giant cell.

In previous studies, mouse placental lactogen I (mPL-I) and mPL-II were localized to trophoblast giant cells in the placenta at midpregnancy. The present study was undertaken to determine whether mPL-I and mPL-II are produced by two distinct populations of giant cells or by the same cells. A heterogeneous population of cells that included trophoblast giant cells was obtained by enzymatic dispersion and Percoll gradient centrifugation of placentas from days 7 and 9 of pregnancy. Cells from day 7 of pregnancy were cultured in serum-free medium for 5 days, and cells that contained mPL-I, mPL-II, or both mPL-I and mPL-II were identified by double-staining immunocytochemistry. The percentage of PL cells that contained both mPL-I and mPL-II increased from about 30% on the first day of culture to about 90% on the third, and then declined to zero by day 5. Between 50% and 60% of the PL cells contained only mPL-I on the first 2 days of culture, and then the percentage of PL cells containing only mPL-I declined. The percentage of cells that contained only mPL-II was low for 3 days (<10%) and then increased to about 80% of the PL-containing cells by day 5. Cells from day 9 of pregnancy were analyzed for the release of mPL-I and/or mPL-II by sequential reverse hemolytic plaque assay. Cells that released only one of the PLs, as well as those that released both PLs, were identified. A shift was present in the type of PL released by the cells when they were followed for two consecutive days of culture. On day 1, most of the plaque-forming cells released only mPL-I, but by day 2, the fraction of plaque-forming cells that released only mPL-I declined whereas the fraction that released only mPL-II increased. Cells that released only mPL-I on the first day of culture and both mPL-I and mPL-II or only mPL-II on the second day of culture were observed. These data suggest that under these culture conditions, PL cells follow a pathway in which they initially produce only mPL-I, then both mPL-I and mPL-II, and finally only mPL-II. In vivo, there is a shift at midpregnancy in the type of PL that is produced by the mouse placenta, and these data suggest that this shift results, at least partly, from a change in gene expression in one population of giant cells.

Animals↗
PubMed1992

Distribution of DNA polymerase alpha during nuclear division cycles in Drosophila melanogaster embryo.

An immunocytochemical method using a specific monoclonal antibody was employed to detect DNA polymerase alpha in Drosophila melanogaster embryos during the first 13 nuclear division cycles after fertilization. The anti-DNA polymerase alpha antibody stained the ooplasm of the unfertilized egg, indicating that DNA polymerase alpha is maternally stored. Strong nuclear staining with the antibody over the weaker staining of the cytoplasm was observed at interphase throughout the 13 nuclear division cycles. The staining of the cytoplasmic regions surrounding the nucleus was much stronger than the other region of the syncytial cytoplasm until cycle 10. Although prophase nuclei were stained with the antibody, metaphase chromosomes were never stained throughout the 13 cycles. The chromosomal (nuclear) staining reappeared at anaphase until cycle 11 and at telophase in later cycles. The staining of the syncytial cytoplasm except for the cortical region became faint by cycle 13, suggesting the consumption of the maternal storage by this cycle. These results suggest that DNA polymerase alpha dissociates from chromosomes at the beginning of metaphase; then in later mitotic phases, it is transported from the syncytial cytoplasm into nuclei to participate in formation of the active DNA replication enzyme complex.

Animals↗
PubMed1992

[MR imaging of cerebral lesions accompanying stroke in stroke-prone spontaneously hypertensive rats].

Cerebral lesions accompanying stroke in male stroke-prone spontaneously hypertensive rats (SHRSP, n = 10) were examined by both magnetic resonance imaging (MRI) and histological evaluation. T2-weighted MR images (T2-WI), taken 1-2 days after animals showed behavioral hyperactivity, indicated hyperintense regions in the occipital cortex, caudate putamen and/or thalamus. The areas of hyperintensity on T2-WI corresponded to neurodegenerative regions including edema, gliosis, and softening of the tissue. T1-weighted images (T1-WI) did not show any hyperintense regions. However T1-weighted images enhanced by the contrast media Gd-DTPA (Gd-T 1-WI) showed hyperintense spots within some of the hyperintense areas on T2-WI, which exhibited neurodegenerative regions such as thrombus, angionecrosis and hemorrhage in addition to the edematous formation. The hyperintense areas on Gd-T1-WI were smaller than those on T2-WI. In some animals, hypointense spots on T2-, T1- and Gd-T1-WI were found within the hyperintense areas, which corresponded to clots. Extensive histological examination did not reveal any additional cerebral degeneration which had not been detected on the MR images. These findings indicate that MRI is useful for detecting and differentiating various types of cerebrovascular disease in this model.

Aging↗
PubMed1992

Disseminated intravascular coagulation in lupus erythematosus with acute liver damage.

A case of disseminated intravascular coagulation (DIC) in a patient with systemic lupus erythematosus (SLE) with acute liver dysfunction is described. A 37-year-old man with SLE developed acute DIC and marked liver damage after fracture of the right clavicle and pharyngitis. Treatment with high-dose steroids, heparin, antithrombin III, gabexate mesilate, and antibiotics resulted in prompt improvement. The recovery of an SLE patient after acute DIC and marked liver damage is considered very rare. We report here such a case and discuss the previous reports.

Adult↗
PubMed1992

Hospital-onset tuberculosis in compromised host.

A total of 21 patients developed active tuberculosis (TB) during hospitalization. Active TB was identified by bacteria-positive, biopsy or autopsy. Infection was confirmed to the lung, pleura, lymph node and miliary lesions and 7 patients had open tuberculosis. In half of the patients, chest X-ray films demonstrated unusual findings in adult tuberculosis: lower lung field pneumonia and miliary pattern. All the patients suffered from severe underlying diseases and an intensive therapy with steroid, immunosuppressive agents, antitumor drugs, radiation and operation was found as predisposing factors for TB occurrence. Nine patients recovered from current infection with anti-tuberculosis drugs; 14 patients died and TB directly caused death in 8 patients. These data strongly suggest that TB is one of the most important infections in compromised hosts. We emphasize that this infection presents a serious clinical problem in a general hospital today.

Aged↗
PubMed1992

Genetic analysis of systemic lupus erythematosus: association with a T cell receptor restriction fragment length polymorphism in Japanese patients.

Many studies have suggested the involvement of multiple genetic loci in the development of systemic lupus erythematosus (SLE). We have analyzed the correlation between various genetic markers and the susceptibility to SLE. In this study, the association of SLE and restriction fragment length polymorphism (RFLP) of T cell receptor gene was evaluated. The cDNA for constant regions of alpha, beta and gamma chain were used as probes and RFLPs were analyzed after digestion with Eco RI, Bam HI, Pst I, Pvu II, Hind III and Bgl II. Among them, polymorphisms were detected using Bgl II- and Hind III-digested DNA and C beta as a probe. Association with SLE in Japanese patients was found only after digestion with Hind III. The absence of the 13 kb polymorphic band appeared to be correlated with the development of SLE (relative risk = 4.78).

Blotting, Southern↗
PubMed1992

Coexistence of acute monoblastic leukemia and adult T-cell leukemia: possible association with HTLV-I infection in both cases?

A 64 year-old Japanese man who developed acute monoblastic leukemia during the course of adult T-cell leukemia/lymphoma (ATL) was studied. Leukemic cells in the peripheral blood and bone marrow were monoblasts positive for alpha-naphthol butyrate esterase (alpha-NBE) staining, CD11c and CD36 antigens, whereas tumor cells in the pleural effusion were ATL cells positive for CD2, CD4, CD25, CD29 and CD45RA antigens. These two malignant cells had different chromosomal abnormalities. Monoclonal integration of human T-cell leukemia virus type I (HTLV-I) proviral DNA and T-cell receptor C beta gene (TCR C beta) rearrangement were detected in the ATL cells, but not in the leukemic monoblasts. By polymerase chain reaction (PCR) in the peripheral blood mononuclear cells (CD11c+ 98%, CD2+ 4%, CD20+ 0%) not containing ATL cells, the presence of the gag region of HTLV-I was confirmed. These facts indicate that a double positive T cell (CD29+, CD45RA+) was possibly the target cell for HTLV-I infection and that HTLV-I was not directly related to the oncogenesis of the monocyte lineage in the present case, even if it did infect the monocytes. However, there is still an outside possibility that HTLV-I induced acute monoblastic leukemia indirectly.

Antigens, Surface↗
PubMed1992

HTLV-I induced extranodal lymphomas.

HTLV-I induced not only nodal but also primary extranodal lymphomas. In this report we describe 12 patients with HTLV-I induced extranodal T-cell lymphoma collected from the literature and our institute experience. There were 5 males and 7 female patients of middle age positive for HTLV-I antibody. The sites of primary tumor were gastrointestinal, Waldeyer's ring, skin, facial sinuses, and the pleura. All of these were histologically diffuse lymphomas and most of them were found to be a helper/inducer T-cell phenotype, showing integration of HTLV-I proviral DNA. Late leukemic changes and skin infiltration often occurred, but hypercalcemia was rare. Survival time varied from 4 to 35 months, and late organ infiltrations were common. These HTLV-I induced extranodal lymphomas were compared with HTLV-I unrelated extranodal lymphomas or HTLV-I induced nodal lymphomas (lymphoma type ATL). Between 1981 and 1990, we had 110 ATL patients and of these, 5 (4.6%) were HTLV-I induced primary extranodal lymphomas. The frequency of HTLV-I induced extranodal lymphoma might be much higher than expected because until now attention has not been paid to this entity. From the present review, it is suggested that HTLV-I could cause primary extranodal lymphoma which may have some different characteristics from other types of lymphoma. Therefore, patients with T-cell extranodal lymphomas should be investigated further for the presence of HTLV-I antibody and the tumor cells should be examined for the integration of HTLV-I proviral DNA using Southern blot analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Liver microsomal mixed-function oxidases in response to dietary whole egg protein levels in rats.

Relation between the activity of liver microsomal mixed-function oxidase system and dietary protein level was investigated in rats using purified whole egg protein, i.e. free from limiting amino acids. The animals were given either a diet containing 0, 5, 10, 20 or 40% of protein (experiment 1) or a diet containing 5, 10, 15 or 20% of protein (experiment 2) for 16 days. In experiment 2, half of the rats of each group were intraperitoneally injected sodium phenobarbital (PB) to induce the mixed-function oxidase system. The cytochrome P-450 content plateaued even at 5% level of dietary protein in experiment 1 and in the PB-untreated groups of experiment 2. However, it showed the highest value at 15% protein level in the PB-treated groups of experiment 2, indicating a shift of the response peak to a higher protein level due to an increase in protein requirement. Cytochrome P-450 reflected most specifically the dietary protein levels when the enzyme system was induced by PB. The 15% protein level, equivalent to 14.1 protein calories %, is a little higher than the optimal dietary level of whole egg protein ever obtained by usual nutritional indices.

Animals↗
PubMed1992

Mechanism of action of an antifungal antibiotic, RI-331, (S) 2-amino-4-oxo-5-hydroxypentanoic acid; kinetics of inactivation of homoserine dehydrogenase from Saccharomyces cerevisiae.

An antifungal antibiotic (S) 2-amino-4-oxo-5-hydroxypentanoic acid, inhibited the biosynthesis of the aspartate family of amino acids (methionine, isoleucine and threonine) followed by the inhibition of protein biosynthesis in Saccharomyces cerevisiae. This inhibition was effected by impeding the biosynthesis of their common intermediate precursor, homoserine. The inhibition of biosynthesis of homoserine by the antibiotic was attributable to inactivation of homoserine dehydrogenase [EC 1.1.1.3], which is involved in the conversion of aspartate semialdehyde to homoserine in the metabolic pathway leading to threonine, methionine and isoleucine. Since such enzymic activity is not present in animal cells, the selective antifungal activity of the antibiotic is thus explained.

Aminolevulinic Acid↗
PubMed1992

[A case of allergic bronchopulmonary aspergillosis with no history of bronchial asthma].

A 53-year-old male was admitted to our hospital because of an abnormal shadow in the left upper lung. Bronchofiberscopy revealed edematous mucosa and pus at the orifice of the left upper lobe bronchus. Pathological examination revealed bronchial inflammatory change with infiltration of eosinophils and also the existence of aspergillus in the pus. Mild eosinophilia and elevation of serum IgE level were observed in the peripheral blood, and serum precipitin against Aspergillus fumigatus was positive. Bronchogram showed central bronchiectasis, and the diagnosis of allergic bronchopulmonary aspergillosis (ABPA) was made. In cases of ABPA, bronchial asthma is usually present prior to presentation, but this patient had no history of asthma even though airway hyperresponsiveness to methacholine was confirmed.

Aspergillosis, Allergic Bronchopulmonary↗
PubMed1992

Tolerance of the liver as measured by ketone body ratio and hepatocyte energy charge to 120 minutes acute venous congestion in dogs.

Although acute passive hepatic congestion (APHC) sometimes occurs in patients undergoing open heart surgery or liver transplantation, the effects and safety limits of APHC on hepatic energy status have yet to be investigated. The present study reports an APHC model in 11 dogs in comparison with a control in 9 dogs by clamping the throacic inferior vena cava with passive venovenous shunt (APHC group) and by clamping the same with an active shunt at a rate of 60 ml/min/kg (control group). We investigated the effects of 120-min APHC on hepatic energy status by assessing the changes in arterial ketone body ratio (KBR) and hepatic energy charge (EC). After induction of the APHC, portal vein pressure elevated significantly to almost three times the control level. KBR decreased significantly for 60 min as compared with that of the control, but gradually recovered thereafter, returning to the preclamping level after reversal. Although total hepatic blood flow after 60-min clamping was approximately 18% of the preclamping value, no significant differences in EC and KBR values were seen after 60-min clamping as compared with preclamping and the control. All dogs in both groups survived at least 1 week. In this experimental model, 120-min APHC had no long-term effects on hemodynamics and energy production in the liver.

Acute Disease↗
PubMed1992

A novel low molecular weight factor detected in the cytosol of guinea pig neutrophils to enhance superoxide anion production.

Cytosolic low molecular components in guinea pig neutrophils were examined for the activity to enhance superoxide anion (O2-)-generating NADPH oxidase activity. A component was separated by Sephadex G-25 gel filtration from high molecular weight components, the latter revealed NADPH oxidase activity in a cell-free system in combination with the membrane fraction and arachidonic acid. Addition of this cytosolic low molecular weight component to the cell-free system significantly enhanced NADPH oxidase activity, though this component did not substitute the high molecular weight components in constituting the system. The low molecular weight NADPH oxidase activation factor (LMWAF) found here was not of protein nature, since protease treatment failed to reduce its activity. This factor did not contain phosphate, and was neither flavin nor guanine nucleotide. Though LMWAF was extractable with chloroform-methanol, it was not identical with diacylglycerol.

Animals↗