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Biomedical subjects

H Akamatsu

Publications and source records attributed to H Akamatsu.

At least 109 records · Page 6Linked to original sources
PubMed1992

[A case of pulmonary rupture with primary pulmonary leiomyosarcoma--management by emergency surgical intervention].

We report a case of 18-year-old boy who was admitted to our hospital for hemoptysis and hemothorax caused by rupture in the pulmonary tissue. A tumoral mass was found protruding from the inferior aspect of the left lower lobe towards the diaphragma. A large hematoma was seen in the vicinity of the tumoral mass. An emergency left lower lobectomy was performed and the hematoma was removed. The tumor was yellow in color, soft and 7 cm in diameter. The histological diagnosis was that of primary pulmonary leiomyosarcoma. The resected lobe had a liver-like hard consistency due to extended infiltration of blood resulting from hemorrhages within the tissue located in and around the tumoral mass. Microscopically, the tumor was composed of the spindle-shaped cells with multinucleation along with some clear cell patterns. Recurrence of the tumor appeared six months after the operation, and a second resection of the recurrent leiomyosarcomatous tissue was performed. The patient is still alive for 1 year and 6 months after the first operation.

Adolescent↗
PubMed1991

Effects of subminimal inhibitory concentrations of minocycline on neutrophil chemotactic factor production in comedonal bacteria, neutrophil phagocytosis and oxygen metabolism.

Comedonal bacteria, Propionibacterium acnes, P. granulosum and coagulase-negative staphylococci (CNS) seem to play an important initiating role in the inflammatory process by producing neutrophil chemotactic factors. The attracted neutrophils, after phagocytosis, release inflammatory factors such as reactive oxygen species (ROS). We investigated the effects of minocycline at subminimal inhibitory concentrations (sub-MIC), i.e. one-tenth MIC, on the production of human neutrophil chemotactic factors in comedonal bacteria, and on several inflammatory parameters of neutrophils, including neutrophil phagocytosis and generation of ROS (O2-, H2O2, OH.). ROS generation in a cell-free, xanthine-xanthine oxidase system was also assessed. Production of neutrophil chemotactic factors in all strains of P. acnes, P. granulosum and CNS were significantly suppressed by sub-MIC minocycline. Sub-MIC minocycline effectively reduced three kinds of neutrophil-generated ROS (O2-, H2O2, OH.). However, neutrophil phagocytosis and the ROS generated in a cell-free system were not markedly changed in the presence of sub-MIC minocycline. The results suggest that sub-MIC minocycline has an anti-inflammatory effect by inhibiting the production of neutrophil chemotactic factors in comedonal bacteria as well as ROS generated by neutrophils in the inflammatory process of acne.

Acne Vulgaris↗
PubMed1991

Inhibitory effect of azelaic acid on neutrophil functions: a possible cause for its efficacy in treating pathogenetically unrelated diseases.

It has been shown that acne, hyperpigmentation and lentigo malignant are more or less related pathogenetically to reactive oxygen species (ROS). It has recently been reported that azelaic acid is effective in treating these conditions and that it possesses anti-enzymatic and antimitochondrial activity, including cytochrome-P450 reductase and 5 alpha-reductase in microsomal preparations with nicotinamide adenine dinucleotide phosphate (NADPH). We therefore investigated the effects of azelaic acid on human neutrophil functions, such as chemotaxis, phagocytosis and ROS generation. ROS generation in a cell-free system was also assessed. The results revealed that neutrophil chemotaxis and phagocytosis as well as ROS generated in a xanthine-xanthine-oxidase system were not significantly changed in the presence of azelaic acid. However, azelaic acid markedly decreased O2- and OH. generated by neutrophils. It may be concluded that the reported clinical effectiveness of azelaic acid is partly due to its inhibitory action on neutrophil-generated ROS, leading to a reduction both in oxidative tissue injury at sites of inflammation and in melanin formation.

Chemotaxis↗
PubMed1991

Kojic acid scavenges free radicals while potentiating leukocyte functions including free radical generation.

The effects of kojic acid, a compound that suppresses melanogenesis and is widely consumed in the Japanese diet with the belief that it is beneficial to health, were investigated on several aspects of leukocyte function. Kojic acid significantly decreased the levels of reactive oxygen species (ROS) (O2-, H2O2, OH.) generated by neutrophil and by a cell-free ROS-generating system. In contrast, it significantly enhanced neutrophil phagocytosis and ROS generation, and lymphocyte proliferation stimulated by phytohemagglutinin. In addition, calcium concentration, [Ca2+]i in human neutrophils was increased in the presence of kojic acid. These results suggest that kojic acid is a favorable agent in terms of host defense in that it enhances a number of activities of leukocytes, but scavenges ROS excessively released from cells or generated in the tissues or blood vessels that are potentially injurious to host tissues.

Calcium↗
PubMed1991

Clinical and bacteriologic evaluation of OPC-7251 in patients with acne: a double-blind group comparison study versus cream base.

Twenty-eight patients with acne were assigned to 4 weeks of treatment with OPC-7251 (a new fluoroquinolone derivative) 1% cream or the cream base in a double-blind manner to evaluate the antibacterial effect of the drug on resident bacteria in the hair follicles and to evaluate clinical response. Propionibacterium acnes was isolated from 21 of the 28 acne patients. When the number of P. acnes was compared before and after treatment, the posttreatment P. acnes count in the OPC-7251 1% cream group was significantly (p = 0.000) reduced compared with that in the cream base group. OPC-7251 1% cream was also significantly (p = 0.019) superior to the cream base in terms of clinical response. P. acnes and Staphylococcus epidermidis isolated from the acne lesions were selected for their susceptibility to various antibacterial agents. The minimal inhibitory concentration of OPC-7251 against P. acnes and S. epidermidis was 0.10 to 0.20 and 0.024 to 0.10 micrograms/ml, respectively, which indicates that the drug has a potent antibacterial effect.

Acne Vulgaris↗
PubMed1991

Mechanism of anti-inflammatory action of glycyrrhizin: effect on neutrophil functions including reactive oxygen species generation.

The effect of glycyrrhizin on inflammatory mediators such as neutrophil functions including reactive oxygen species (ROS) generation was examined. Glycyrrhizin significantly decreased neutrophil-generated O2-, H2O2 and OH in a dose-dependent manner. However, the drug did not reduce any of the ROS generated in a cell-free, xanthine-xanthine oxidase system. The drug did not affect neutrophil chemotaxis or phagocytosis, either. The present study indicates that glycyrrhizin is not an ROS scavenger but exerts an anti-inflammatory action by inhibiting the generation of ROS by neutrophils, the most potent inflammatory mediator at the site of inflammation.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

Effects of 13-cis-retinoic acid, all-trans-retinoic acid, and acitretin on the proliferation, lipid synthesis and keratin expression of cultured human sebocytes in vitro.

The aim of this study was to determine the effects of 13-cis-RA, all-trans-RA, and acitretin on the proliferation, lipid synthesis, and keratin expression of human sebocytes in vitro and to elucidate possible mechanisms of retinoid action on sebaceous glands at the cellular level. It was found that 13-cis-RA and all-trans-RA decreased sebocyte proliferation in a dose- and time-dependent manner, with a 13-cis-RA-IC50 of 10(-5) M (after 7 d) and 10(-6) M (after 14 d) and an all-trans-RA-IC50 of 10(-7) M (after 14 d; no IC50 after 7 d). Acitretin inhibited sebocyte proliferation only at 10(-5) M. Furthermore, 13-cis-RA was the most potent inhibitor of acetate incorporation into lipids, which indicated lipid synthesis (48.2% reduction), followed by all-trans-RA (-38.6%), and by acitretin (-27.5%). All retinoids tested markedly decreased the synthesis of triglycerides, wax/stearyl esters, and free fatty acids in cultured sebocytes, whereas squalene synthesis remained uninfluenced and cholesterol synthesis slightly increased. On the other hand, keratin 5 was down-regulated, keratin 17 was up-regulated, and the expression of keratin 13 was virtually unaffected by all retinoids tested. Keratins 6 and 16 were down-regulated by 13-cis-RA and by all-trans-RA, keratin 14 was down-regulated by 13-cis-RA only, and keratin 19 was up-regulated by all-trans-RA. These investigations indicate that 13-cis-RA and, to a lesser extent, all-trans-RA are potent inhibitors of both cell proliferation and lipid synthesis in human sebocytes in vitro, whereas acitretin only decreases lipogenesis in this model. In addition, retinoids may modify the differentiation of sebocytes in vitro by modulating keratin expression. Models of cultured human sebocytes are useful tools for further investigations on the sebaceous gland and its activity at the cellular level.

Acitretin↗
PubMed1991

Effects of subminimal inhibitory concentrations of erythromycin, tetracycline, clindamycin, and minocycline on the neutrophil chemotactic factor production in Propionibacterium acnes biotypes 1-5.

Biotypes 1-5 Propionibacterium acnes (P. acnes) strains were grown in the presence of 1/10 minimal inhibitory concentrations (sub-MIC) of erythromycin (EM), tetracycline (TC), clindamycin (CLDM), or minocycline (MINO) and their culture filtrates were assayed for human neutrophil chemotactic activity using Boyden chamber methods. The addition of sub-MIC of MINO to the medium strongly suppressed the neutrophil chemotactic activity of the culture filtrates of P. acnes strains of all biotypes. In contrast, with sub-MIC of EM, TC, or CLDM, the activity of the culture filtrates of P. acnes strains of biotypes 2 and 3 were suppressed but those of biotypes 1, 2, and 5 were not. These results indicate that sub-MIC of MINO is capable of decreasing the inflammatory capacity of P. acnes strains of all biotypes.

Acne Vulgaris↗
PubMed1991

Effects of cepharanthin on neutrophil chemotaxis, phagocytosis, and reactive oxygen species generation.

The effects of cepharanthin on inflammatory parameters such as neutrophil chemotaxis, phagocytosis and reactive oxygen species (ROS) generation, were examined. Cepharanthin significantly decreased the levels of O2-, H2O2, and OH. generated by neutrophils. H2O2 and OH. generated in a cell-free, xanthine-xanthine oxidase system were also reduced in the presence of cepharanthin. However, the drug did not affect neutrophil chemotaxis or phagocytosis. The present study indicates that cepharanthin is an effective ROS scavenger, exerting its anti-inflammatory action by reducing the potent ROS species excessively generated in tissues and organs, especially at the sites of inflammation.

Alkaloids↗
PubMed1991

Evaluation of right ventricular function using gated equilibrium blood pool radionuclide ventriculography in patients with congenital volume and pressure overload late after surgical repair.

The effects of congenital right ventricular pressure and volume overload were studied in 3 patients with pulmonary stenosis, 7 with atrial septal defect and 6 with atrial septal defect plus pulmonary stenosis late after successful surgical correction. Gated equilibrium blood pool radionuclide ventriculography was used to measure right ventricular function at rest and during exercise and to compare it with eight normal subjects. Right ventricular ejection fractions at rest and during exercise were measured to be 61 +/- 9% and 66 +/- 13%, respectively, in the group with pulmonary stenosis, 49 +/- 7% and 54 +/- 8% in the group with atrial septal defect, and 65 +/- 13% and 69 +/- 13% in the group with atrial septal defect plus pulmonary stenosis. The values in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis were significantly higher than the control subjects (45 +/- 5% and 51 +/- 5%, p less than 0.01). The peak filling rate at rest and during exercise was also significantly higher in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis than in controls (at rest, 2.72 +/- 0.72, 2.53 +/- 0.94 vs. 1.64 +/- 0.24 p less than 0.05; during exercise, 4.38 +/- 1.23, 4.13 +/- 1.18 vs. 2.52 +/- 0.62, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Effects of azelastine on neutrophil chemotaxis, phagocytosis and oxygen radical generation.

The effects of azelastine, an orally active anti-allergic drug, on several inflammatory parameters of human neutrophils, including human neutrophil chemotaxis, phagocytosis and generation of reactive oxygen species (ROS), was examined. ROS generated in a cell-free, xanthine-xanthine oxidase system was also assessed. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.). Azelastine significantly inhibited human neutrophil phagocytosis and the generation of O2-, H2O2, OH. by human neutrophils. However, the drug did not markedly affect human neutrophil chemotaxis or the ROS levels generated in the xanthine-xanthine oxidase system. The present study indicates that azelastine may exert an anti-inflammatory action by inhibiting human neutrophil phagocytosis as well as oxygen radical generation at the sites of inflammation.

Cell Movement↗
PubMed1991

[Cerebral blood flow velocities in the anterior cerebral arteries and basilar artery. III. Investigation in hydrocephalus (Part 2)].

We made 10 measurements of Pourcelot's index of resistance (RI) in the anterior cerebral artery (RI-ACA) and basilar artery (RI-BA), and RI ratio (= RI-ACA/RI-BA) in seven cases of hydrocephalus before and after treatment. The mean values of RI-ACA (0.831 +/- 0.050, mean +/- SD), RI-BA (0.800 +/- 0.053) and RI ratio (1.039 +/- 0.030) before treatment were significantly higher than in normal infants. Two hours after treatment, the mean RI-ACA (0.654 +/- 0.099) was lower than in normal infants, and RI-BA (0.684 +/- 0.101) were normalized. Before treatment, the mean value of RI-ACA was higher than that of RI-BA. All RI ratios were higher than 1.00. After treatment, the mean RI-ACA was lower than the mean RI-BA. All RI ratios were normalized and lower than 1.00 (0.957 +/- 0.024).

Basilar Artery↗
PubMed1991

[Human fetal mast cells under development of the skin and airways].

We made histochemical and ultrastructural studies of mast cells of the skin and airways in human fetuses (7 to 40 weeks' gestation) and newborn infants. Epithelial differentiation of the skin and bronchial airways was assessed of immunohistochemical characteristics, especially on their basal cells. Histological phenotype and the characteristics to anti-total keratin antibody became identical with the phenotype in the adult by the 11th and 36th week of gestation, respectively. Interstitial fibroblastoid cells appeared oval in shape and remained relatively immature to the termination. Mast cells were first recognized by electron microscopy in the fetal skin of 18-week-old fetuses and histochemically detected in both skin and airways of 24-week-old fetuses. Mast cell counts under high power magnification (40X optical lens) light microscopy gradually increased and made a relatively dramatic rise in the early postnatal periods. The cytoplasm of mast cells showed irregular pseudopod-like elongations which gradually developed microvillous protrusions. It contained immature granules composed of varieties of morphology such as amorphous dense bodies, vesicles with dense cores, particulates and their compound forms. They were located in a corner of the cytoplasm surrounded by lamellated rough-surfaced endoplasmic reticulum. These granules became scattered widely in the cytoplasm showing distinct particulate type. Granules typical of the scroll type became dominant in the process of maturation, and the transformation of crystal-substructures occasionally took place. Prior to birth, mast cell granules fully developed as mature as those in the adult. This process of granule maturation is indicative of a reversed proceeding of slow degranulation, which is commonly seen in the so-called mucosal mast cells.

Epithelial Cells↗
PubMed1991

[Cerebral blood flow velocities in the anterior cerebral arteries and basilar artery. II. Investigation in very low birth weight infants].

We studied the values of the Pourcelot's index of resistance in the anterior cerebral artery (RI-ACA) and basilar artery (RI-BA) in very low birth weight infants weighing less than 1,500 g at birth. At the time of measurements, their postconceptional ages were 32, 34, 36, 38, 40 and 42 weeks. The mean value of RI-ACA (0.744 +/- 0.026, +/- SD) was significantly lower than that of RI-BA (0.766 +/- 0.026) (p less than 0.001), and they were higher than those in normal term infants. However, the mean value of RI-ACA and RI-BA, averaged from the measurements of postconceptional ages at 38, 40 and 42 weeks, showed no significant difference from those of normal term infants. In contrast, the mean value of RI ratio (= RI-ACA/RI-BA) in very low birth weight infants showed no significant difference from that of normal term infants.

Analysis of Variance↗
PubMed1991

[A case of primary mediastinal seminoma].

Primary mediastinal seminoma is a rare clinical entity. Because of its high malignancy, we often find it only when it grows very large so we can't resect it completely. Our patient came with asthma attack and abnormal shadow on chest X-ray was pointed out. Germinal cell tumor was diagnosed by thoracoscopy and resection of the tumor was performed. Postoperative radiation therapy also was performed. Our case is alive in good health for 1 year postoperatively and good prognosis will be expected.

Adult↗
PubMed1991

[Cerebral blood flow velocities in the anterior cerebral arteries and basilar artery. I. Investigation in term infants].

We studied the value of Pourcelot's index of resistance in the anterior cerebral arteries (RI-ACA) and basilar artery (RI-BA) in 69 measurements of term infants on days 1, 5, 10, 15, 20, 30 and 60. The mean value of RI-ACA (0.723 +/- 0.038, +/- SD) was significantly lower than that of RI-BA (0.750 +/- 0.041) (p less than 0.001). RI-ACA values were higher than RI-BAs in only five measurements (7.2%). The values of RI-ACA and RI-BA decreased from the first day to the fifth day of life. They increased continuously and showed their highest values on the day 15. After the 15th day, they decreased mildly again. The values of RI ratio (= RI-ACA/RI-BA) were stable (0.96-0.97).

Basilar Artery↗
PubMed1990

The inhibition of free radical generation by human neutrophils through the synergistic effects of metronidazole with palmitoleic acid: a possible mechanism of action of metronidazole in rosacea and acne.

Metronidazole is clinically effective in treating not only rosacea but also acne inflammation. Yet it is generally considered not to be very effective in inhibiting the growth of anaerobic Propionibacterium acnes. We report here our investigation into the synergistic effects of metronidazole and palmitoleic acid on the anaerobic growth of P. acnes as well as on human neutrophil functions, including the generation of reactive oxygen species (ROS). Both metronidazole and palmitoleic acid, when used alone, only slightly inhibited the growth of P. acnes, and no significant decrease in human neutrophil functions, including the generation of ROS, was observed. But metronidazole used in the presence of palmitoleic acid markedly inhibited the anaerobic growth of P. acnes and decreased ROS generation by neutrophils. However, ROS generated in the xanthine-xanthine oxidase system were not affected. Metronidazole was shown to be clinically effective by decreasing neutrophil-generated ROS at the sites of inflammation with the aid of palmitoleic acid, which is generally present in human skin. By inhibiting oxidative tissue injury under in vivo conditions, treatment with metronidazole results in remarkable improvement of rosacea and acne.

Acne Vulgaris↗