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Biomedical subjects

M Aoyama

Publications and source records attributed to M Aoyama.

At least 91 records · Page 5Linked to original sources
PubMed1994

Parallel tubular granules in human immature neutrophils--an electron microscopic study.

Unique rounded granules consisting of clustered parallel tubules, 29-31 nm in diameter, with occasional, flocculent or amorphous electron-dense material (parallel tubular granules, PTGs) were found in immature neutrophils in the bone marrow in a case of chronic neutrophilic leukemia (CNL). PTGs were positive for electron microscopic myeloperoxidase. Since no structures similar to PTGs have been documented, we investigated the bone marrow of 65 adult patients with hematologic diseases, and 7 adult patients with miscellaneous non-hematologic diseases, by electron microscopy. The results showed that no PTGs were found in any cases other than the original CNL case. These findings suggest that PTGs are rare granules representing certain primary granules. In addition, the presence of PTGs might be helpful in diagnosing CNL.

Adolescent↗
PubMed1994

[Nasal NK-cell lymphoma].

A 75-year-old man was admitted to our hospital on June 1st, 1993, because of nasal obstruction, epistaxis, fever, night sweats and weight loss. Examination disclosed a 2-cm white necrotic mass in the nasal septum, and a biopsy disclosed non-Hodgkin's lymphoma, diffuse, mixed-type. Imprint smears showed cytoplasmic azurophilic granules in the tumor cells. Dense granules were demonstrated by electron microscopy. The tumor cells were CD1-2+3-4-7+8-16+56+57-, and T cell receptor genes were in germline configuration. NK activity against K562 was strongly positive. Based on morphologic, phenotypic, immunogenotypic, and cytotoxic findings, the tumor cells seemed to be derived from activated NK cells. Because the tumor cells were positive for the EB virus and CD21 antigen, EB virus seemed to have infected CD21-positive NK cells and transformed them. MDR P-glycoprotein was also positive. This finding may explain why nasal lymphomas are resistant to chemotherapy and have a poor prognosis.

Cell Transformation, Viral↗
PubMed1993

Use of polyglycolic acid mesh with a new double pursestring technique in renal trauma: an experimental study.

Repair of major kidney lacerations with conventional techniques is extremely difficult and 'through and through' suturing is associated with further loss of viable tissue because it promotes scarring. In this study, we investigate the haemostatic and viable parenchyma salvaging effect of an alternative, new wrapping technique in an experimental renal trauma model. This resulted in immediate haemostasis in all 25 animals, while the same injury caused excessive haemorrhage with 50 per cent mortality in eight untreated controls. This technique differs from other wrapping methods because no additional suturing for the application of PAM or haemostasis is required. It is an easy, rapid procedure which decreases the operating time and may allow successful repair in major lacerations of the kidney.

Animals↗
PubMed1993

Characterization of pigmented granules in minocycline-induced cutaneous pigmentation: observations using fluorescence microscopy and high-performance liquid chromatography.

We describe a technique to facilitate histopathological detection and quantitative measurement of trace amounts of tissue minocycline. In a patient with minocycline-induced hyperpigmentation, a series of biopsies were taken from the affected skin over a period of 54 months, and examined for tissue minocycline deposition. Frozen sections treated with 1 M MgCl2-ethanol yielded minocycline-specific yellowish fluorescence, the location of which corresponded to clumps of granular deposits in the dermis. A decrease in the number of fluorescent granules correlated with the clinical resolution of hyperpigmentation and a significant decrease in the tissue minocycline level. Our data also provide further support for the concept that the pigment granules contain insoluble complexes of minocycline chelated with iron. The fluorescence technique is simple, sensitive, and reproducible.

Chromatography, High Pressure Liquid↗
PubMed1993

Heterogeneity of CD7+ 4- 8- 1- leukemia: usefulness of cytoplasmic antigen detection for subclassification.

We identified CD3 and myeloperoxidase (MPO) antigens in the cytoplasm of leukemic cells from 15 patients with CD7+ 4- 8- 1- leukemia. Seven patients, five of whom had a mediastinal mass, had only cytoplasmic CD3 (cCD3) antigen; these seven were regarded as possibly being of T-lineage type. Six patients, one of whom had a mediastinal mass, showed both cCD3 and MPO; they were considered to have mixed lineage type. Two patients had neither cCD3 nor cytoplasmic myeloid antigens; they were therefore considered to have stem cell type. These two latter types were considered as the subgroups: mixed lineage or stem cell type. Patients with T-lineage type were good responders to L-17M therapy; four out of five who received L-17M therapy achieved complete remission. There were significant differences between the two subgroups in relapse-free survival, patients with T-lineage type exhibiting better prognosis than other types (p < 0.05).

Adult↗
PubMed1991

Metabolism of glycyrrhetic acid by rat liver microsomes--III. Male-specific glycyrrhetinate dehydrogenase.

Glycyrrhetinate (GA) dehydrogenase localized in microsomes of rat liver catalyses the oxidation and reverse reduction of 18 beta-glycyrrhetic acid (GA), an aglycone of glycyrrhizin and a main component of liquorice, to 3-keto-18 beta-glycyrrhetic acid (3-ketoGA). The enzyme activity was detected in microsomes of adult males, but not in those of adult females. It was not observed in infant males but appeared 6 weeks after birth, increased gradually and reached the maximum level at 12 weeks after birth, whereas it was not detected in the hepatic microsomes of females of any age. The administration of estradiol valerate to intact adult males decreased GA dehydrogenase activity remarkably. Castration of male rats also caused a marked reduction of the activity, but the administration of testosterone proprionate to these rats restored it to close to the normal level. On the other hand, ovariectomy of female rats did not bring the activity into existence, but the injection of testosterone proprionate to the ovariectomized rats brought it into a slight existence, in spite of no appearance of the activity by the treatment of testosterone proprionate to intact adult females. The sex-related difference in the activity in adults was eliminated by hypophysectomy of male and female rats, their microsomal activities after the operation being the same, 20-40% of the activity in intact males. Moreover, the administration of estradiol valerate to the hypophysectomized rats did not affect the activity. These results indicate that GA dehydrogenase is male-specific and regulated by sex-hormones through the pituitary.

3-Hydroxysteroid Dehydrogenases↗
PubMed1991

Neuronal responses of the nucleus tractus solitarius to oral stimulation with umami substances.

In order to investigate coding mechanisms of special taste modality (umami), responses of neurons within the nucleus tractus solitarius (NTS) to oral stimulation with monosodium glutamate, disodium 5'-inosinate (IMP) or their mixture were recorded in the conventional electrophysiological method. Results obtained were as follows: Neither MSG-best nor IMP-best neuron was recorded within the NTS as in the primary taste afferents. Some of the sucrose-best neurons, NaCl-best neurons and HCl-best neurons responded to oral stimulation with MSG or IMP. A remarkable synergistic effect was observed in all of the sucrose-best neurons and in some of the NaCl-best neurons but not in all of the HCl-best neurons, when the mixed solution of MSG and IMP was applied into the oral cavity. As to the sucrose-best neurons, potency of the synergism was positively correlated with the responsiveness to sucrose. No correlation was recognized between them in the case of NaCl-best neurons. These results suggest a view that the sucrose-best neurons and the NaCl-best neurons which show the synergism may participate in coding umami taste.

Afferent Pathways↗
PubMed1990

Metabolism of glycyrrhetic acid by rat liver microsomes-II. 22 alpha- and 24-hydroxylation.

18 beta-Glycyrrhetic acid (GA, an aglycone of glycyrrhizin) is converted to 3-oxo-18 beta-glycyrrhetic acid (3-oxoGA) in the presence of NADP+ by rat liver homogenates, but GA was converted in the presence of NADPH to two other metabolites showing lower Rf values on thin-layer chromatography (TLC) than those of GA and 3-oxoGA by postmitochondrial supernatant of rat liver. The GA-metabolizing activity in the presence of NADPH was localized in microsomes, similar to localization of GA-oxidizing activity to 3-oxoGA. The GA-metabolizing activity required NADPH as a cofactor and O2 for full activity and was inhibited with CO, suggesting the hydroxylation reaction of GA by cytochrome P450. Two metabolites (I and II, lower and higher Rf values on TLC, respectively) were purified on preparative TLC. Mass spectral (MS) analyses of II and methyl ester of acetylated I indicated the formation of monohydroxylated metabolites. On the basis of 3H- and 13C-NMR assignments I and II were identified to be 22 alpha- and 24-hydroxy-18 beta-glycyrrhetic acids, respectively. 3-OxoGA and 3-epi-18 beta-glycyrrhetic acid (3-epiGA) seem to be also hydroxylated at C-22 and C-24. A metabolite of 3-oxoGA showing a lower Rf value was also identified as 22 alpha-hydroxy-3-oxo-18 beta-glycyrrhetic acid by MS and 3H- and 13C-NMR spectral analyses. In 22 alpha-hydroxylation the best substrate was 3-oxoGA, followed by GA and 3-epiGA. On the other hand, for 24-hydroxylation the best substrate was GA, then 3-oxoGA, and 3-epiGA in order. However, 18 alpha-glycyrrhetic acid (18 alpha-GA) was a poor substrate for both 22 alpha- and 24-hydroxylation.

Animals↗
PubMed1990

Mechanisms of atrial natriuretic peptide (ANP) secretion by rat hearts perfused in vitro--Ca2(+)-dependent signal transduction for ANP release by mechanical stretch.

Effects of temperature, contraction frequency, and intraatrial pressure on immunoreactive ANP release were investigated in isolated rat hearts perfused in Langendorff or working mode. A reduction of temperature from 37 C to 27 degrees C caused a decrease of ANP release by 64% indicating its marked temperature-dependency (Q10 = 2.92). An increase of atrial contraction frequency from 300 to 500/min in Langendorff-perfused hearts did not cause a significant change in the ANP release. An elevation of left atrial filling pressure of working hearts from 8 to 18 and 28 cmH2O was associated with pressure-dependent, and reversible increase of the ANP release. This pressure-induced release of ANP was inhibited in a low calcium (50% Ca2+) medium or by nifedipine (10(-7) M). N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7, 10(-7)M), a potent calmodulin inhibitor, or ryanodine (10(-8)M) had similar inhibitory action against the pressure-induced increase of ANP release. These results indicate that ANP secretion is primarily regulated by mechanical stretch or distension of the atrial wall, while the atrial contraction frequency is less important as a physiological stimulus for the secretion. The stretch-induced ANP secretion may require an influx of calcium through the voltage-dependent Ca2+ channels. It was also suggested that Ca2+ release from the sarcoplasmic reticulum leading to an activation of calcium-calmodulin kinase may be included in the intracellular processes of ANP release by mechanical stretch.

Animals↗
PubMed1990

[Cardiotoxicity study of ME2303 with the interval intravenous injections to rats].

Cardiotoxic effects of ME2303 were studied upon interval intravenous administrations to rats in comparison with those of doxorubicin (ADR). ME2303 at two dose levels of 3 and 9 mg/kg/day or ADR at a dose levels of 3 mg/kg/day was injected once a week for 3 weeks to female Sprague-Dawley rats (SPF) of 5-weeks of age. ADR depressed body weight gain, decreased food intake and increased water intake. Microscopic observation on the myocardial tissues revealed that ADR caused necrosis and cell infiltration, edema and disarrangement of myofibrils in some of ADR-treated rats. On the other hand, ME2303 showed no significant effects except that some decrease of food intake was observed at a dose level 9 mg/kg/day. No changes in left ventricular functions were observed in perfused hearts isolated from ADR- or ME2303-treated rats. However, about 133 ng/g of ADR remained in the hearts even at 1 week after the final administration whereas ME2303 or its metabolites were not detected, suggesting that ADR may cause disturbance of ventricular function and more cardiomyopathy after a longer term than 1 week following the final administration. These results suggest that the cardiotoxicity of ME2303 is weaker than that of ADR in rats.

Animals↗