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Biomedical subjects

M Akao

Publications and source records attributed to M Akao.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Clinical study of prulifloxacin on infectious enteritis. Japan Research Committee of Prulifloxacin, Research Group on Infectious Enteritis].

Prulifloxacin (PUFX), a new quinolone antimicrobial agent, was administered to a total of 122 patients and carriers to investigate its clinical efficacy, safety and usefulness in infectious enteritis (bacillary dysentery, enteritis caused by Salmonella spp. and enteropathogenic E. coli, cholera and so on). In addition, the minimum inhibitory concentration (MIC) of UFX (active compound) was determined against each clinical isolate, and compared with that of ciprofloxacin (CPFX), ofloxacin (OFLX), tosufloxacin (TFLX) and nalidixic acid (NA). The correlation between the concentration of UFX in feces and the change of the fecal microflora were also investigated when PUFX was administered to the patients with acute infectious enteritis. A daily dose of 400 mg of PUFX was administered orally in two divided doses (morning and evening) for 5 days, with the exception of 7 days administration against salmonella enteritis and 3 days administration against cholera. 84 cases were adapted for evaluating the usefulness. The clinical efficacy was 100% in all the enteritis except salmonella enteritis, in which it was 88.9% (8/9 cases). On the bacteriological efficacy, the elimination rate was 100% in all isolates except Salmonella spp., in which it was 75.0% (12/16 cases). As for the adverse effect, uriticaria in moderate degree was observed in 1 (0.9%) of 109 cases. Abnormal changes in laboratory findings were seen in 3 (3.0%) of 100 cases, consisting of 1 with eosinophilia and 2 with elevated S-GPT, although they were all slight in degree. The usefulness rate was 65.5% (55/84 cases) for "very useful" and 95.2% (80/84 cases) for "very useful" and "useful". MIC90 of UFX against Shigella spp., Salmonella spp., E. coli and V. cholerae, was 0.025, 0.05, 0.025 and 0.05 microgram/ml, respectively. These values were the same as those of CPFX and TFLX, and superior to OFLX and NA. UFX concentrations in feces followed by administration of PUFX in 3 cases with acute infectious enteritis were higher than that of MIC90 of UFX against Shigella spp., Salmonella spp., E. coli and V. cholerae. The changes of the fecal microflora, which influence the efficacy and safety of PUFX, were not observed.

Adult↗
PubMed1996

Halothane reduces myofilament Ca2+ sensitivity during muscarinic receptor stimulation of airway smooth muscle.

This study used a beta-escin-permeabilized canine tracheal smooth muscle preparation to test the hypothesis that the volatile anesthetic halothane decreases myofilament Ca2+ sensitivity by inhibiting the membrane receptor-linked second messenger systems that regulate myofilament Ca2+ sensitivity and not by inhibiting Ca(2+)-calmodulin activation of the contractile proteins. Acetylcholine (ACh) caused a GTP-dependent increase in force at constant submaximal cytosolic Ca2+ concentration. ACh, guanosine-5'-O-(3-thiotriphosphate), and the protein kinase C agonist 12,13-phorbol dibutyrate each significantly decreased the concentration of free Ca2+ producing a half-maximal response from 0.77 +/- 0.09 microM (Ca2+ alone) to 0.16 +/- 0.01, 0.19 +/- 0.02, and 0.37 +/- 0.03 microM, respectively, demonstrating an increase in myofilament Ca2+ sensitivity. Halothane (0.92 +/- 0.12 mM) had no effect on the free Ca2+ concentration-response curves generated by Ca2+ alone. However, in the presence of 3 microM ACh plus 10 microM GTP to maximally activate muscarinic receptors, halothane significantly increased the EC50 for free Ca2+ from 0.17 +/- 0.01 microM to 0.38 +/- 0.03 microM. These findings suggest that halothane decreases myofilament Ca2+ sensitivity in beta-escin-permeabilized canine tracheal smooth muscle by inhibiting the membrane receptor-linked second messenger systems that regulate myofilament Ca2+ sensitivity.

Acetylcholine↗
PubMed1996

[A case of small cell carcinoma (oat-cell type) of the esophagus].

We experienced a case of small cell carcinoma of the esophagus treated by operation. A 57-year-old female was examined for a complaint of dysphagia. The radiologic and endoscopic examination revealed Borrmann III like tumor (8 cm long) at lower esophagus (EiEa). Endoscopic biopsy led to a diagnosis of poorly differentiated squamous cell carcinoma. Chest X-ray and chest CT showed no lung tumor, no swelling of lymph node and no invasion of esophageal tumor. Lower esophagectomy, proximal gastrectomy and esophago-gastrostomy through intrathoracic route was performed. Histopathologically, resected tumor was diagnosed as small cell carcinoma (Oat-cell type) with rosette formation. Grimerius stain revealed negative reaction and immunohistochemical stain by NSE monoclonal antibody revealed positive reaction in tumor cells. Histological staging was a0, n1(+), M0, P1(zero), stage II. Recurrence at paraaortic lymph node occurred in 2 months after the surgery. Chemotherapy (CDDP, 5-FU and Leucovorin) was performed, but not effective. She died from multiple metastases in 5 months after the surgery (6 months after the diagnosis).

Adult↗
PubMed1996

[A case of so-called carcinosarcoma of the lung].

A 69-year-old male was followed at our institute for the purpose of hemo-dialization. During follow-up, a tumor shadow (phi 6.5 x 7.0 cm) was found in rt. S5 by chest X-ray. This tumor was diagnosed as squamous cell carcinoma by TBLB. Right middle lobectomy (R 2 a) was performed. Histological staging was pT 2 N 2 M 0, stage IIIa. This tumor was cystic, filled with keratin like substance. Histologically, the cyst wall was composed of well differentiated squamous cell carcinoma and sarcomatous stroma which didn't differentiate into bone, cartilage, muscle, and etc. Immunohistologically, sarcomatous stroma was positively stained by vimentin, negatively by keratin and EMA. This patient survived 7 months with recurrence.

Aged↗
PubMed1996

Cytotoxicity of synthetic barium hydroxyapatite.

Barium hydroxyapatite (Ba10(PO4)6(OH)2, Ba-HAp) was synthesized by a wet method using Ba(OH)2.8H2O and (NH4)2HPO4 as starting materials. The Ba-HAp obtained had a Ba/P atomic ratio of 1.76 and contained CO3 groups. The Ba-HAp was sintered at 1073 K for 12 hours. The sintered Ba-HAp had a three point bending strength of 29 MPa and Young's modulus of 27 GPa. Cytotoxicity of the sintered bodies and particles was tested using L-cells. The sintered Ba-HAp showed no cytotoxicity, and the cells were closely in contact with the surfaces of sintered Ba-HAp. Morphological observation of the cell around the Ba-HAp particles also showed no cytotoxicity. However, cell growth was inhibited by Ca adsorption on the Ba-HAp particles. These results suggested that the Ba-HAp had no cytotoxicity and can be applied as a bioactive X-ray opaque material.

Adsorption↗
PubMed1995

Surgically resected adrenal leiomyoma: report of a case.

This report describes the case of a 48-year-old woman found to have a leiomyoma of the left adrenal gland after presenting with anemia and hypertension. An upper gastrointestinal series revealed a mass in the posterior region of the body that distorted the stomach. A computed tomography (CT) scan showed a well-circumscribed mass with a high-density outline in the left adrenal gland, and magnetic resonance imaging (MRI) revealed a homogeneous mass. Multiple catheter samplings of vena cava blood revealed a slight elevation of epinephrine and norepinephrine in the left adrenal vein and the left renal vein. Thus, asymptomatic pheochromocytoma of the left adrenal gland was highly suspected as a preoperative diagnosis and a left adrenalectomy was performed. However, histologic examination subsequently revealed findings suggestive of leiomyoma of the adrenal gland, which was confirmed by electron microscopy. The patient's postoperative course was uneventful and she has remained free from any further symptoms.

Adrenal Gland Neoplasms↗
PubMed1995

Effect of hydroxyapatite microcrystals on macrophage activity.

Hydroxyapatite (HAp) microcrystals were synthesized by a neutralization reaction of Ca(OH)2 suspension and H3PO4 solution using an ultrasonic homogenizer. The in vitro interaction of HAp microcrystals with rat peritoneal macrophages was investigated by measuring the viability, acid phosphatase (ACP) activity, lactate dehydrogenase (LDH) activity and intracellular calcium content. HAp calcined at 800 degrees C and alpha-alumina particles (alumina) were used as comparative materials. Macrophages actively phagocytosed HAp microcrystals by dissolving them. However, no damage in macrophages exposed to HAp microcrystals was observed by transmission electron microscopy. Macrophages in the presence of HAp microcrystals showed less ACP and LDH activity and higher intracellular calcium content than those in the presence of calcined HAp and alumina. HAp microcrystals had excellent biocompatibility to macrophages as well as sintered HAp.

Acid Phosphatase↗
PubMed1994

Effects of Sr-hydroxyapatite microcrystal on cultured cell.

Strontium-hydroxyapatite microcrystals (Sr-HAp sol) were produced by a wet method at room temperature with ultrasonic irradiation and were applied to MC3T3-E1, ROS, and L cells for periods of 2, 4, and 6 days in vitro. The effect on cell growth, the variation of LDH and Ca contents in the media, and attachment between cell and microcrystal were investigated. Sintered Sr-HAp and HAp sol were used as controls. A slight inhibitory effect of Sr-HAp sol on cell growth was found. The degree of inhibition was nearly the same as HAp sol. However, it was stronger than sintered Sr-HAp. The contents of LDH in the media increased with the degree of cell inhibition, and the contents of Ca in the media decreased from the initial stage of cell-sol contact. A good attachment of Sr-HAp sol to cultured cells was seen by phase-contrast microscopy and SEM.

Animals↗
PubMed1994

Application of hydroxyapatite-sol as drug carrier.

The application of hydroxyapatite-sol as a drug carrier is being developed. Hydroxyapatite-sol which is a suspension consisting of hydroxyapatite nano-crystals, was synthesized using an ultrasonic homogenizer. The size of the crystals was 40 x 15 x 10 mm3 on average and their specific surface area was 100 m2/g. An amount of a glycoside antibiotics adsorbed onto hydroxyapatite nano-crystals was measured. The drug adsorbed 0.2 mg per 1 mg of hydroxyapatite. The affect of the drug adsorbed onto the hydroxyapatite was investigated using cancer cells. The drug, adsorbed onto the hydroxyapatite nano-crystals, inhibited cancer cell growth.

Adsorption↗
PubMed1993

Inactivation of rifampin by Nocardia brasiliensis.

Rifampin was glycosylated by a pathogenic species of Nocardia, i.e., Nocardia brasiliensis. The structures of two glycosylated compounds (RIP-1 and RIP-2) isolated from the culture broth of the bacterium were determined to be 3-formyl-23-(O-[beta-D-glucopyranosyl])rifamycin SV and 23-(O-[beta-D-glucopyranosyl])rifampin, respectively. Both compounds lacked antimicrobial activity against other gram-positive bacteria as well as the Nocardia species.

Glycosylation↗
PubMed1993

Effect of exercise on strength and chemical composition of rat femur bone.

The effect of exercise on strength and chemical composition of rat femur bone was examined. Ten 5-week-old rats were forced to exercise on a treadmill with a running speed of 20 m/min at set time intervals for a 4-week period. Another 10 rats were kept idle as controls. After exercising, bending tests of the rat femur bones were carried out, and the content ratios of Sr to Ca, Sr/Ca, were measured by energy-dispersive fluorescent X-ray analysis and EPMA line analysis. The strength of the exercise group was greater than that of the control group. The ratio, Sr/Ca, of the exercise group showed a tendency to increase compared to that of the control group. It is clear that the chemical composition of bone varies with the degree of exercise, and that the bone becomes strengthened at the same time.

Animals↗
PubMed1992

An early effect of aflatoxin B1 administered in vivo on the growth of bone marrow CFU-GM and the production of some cytokines in rats.

Our data demonstrate the granulopoietic toxicity of aflatoxin B1 (AFB1) in vivo and show an impact of this mycotoxin on the production of some humoral regulatory factors dealing with the granulopoietic developmental pathway (CSA, IL-1, IL-2). The dose of AFB1 studied represented approximately 1/5 of LD50 for young male rats. An early suppressive effect of AFB1 towards CFU-GM was transient in treated animals. The peak in granulopoietic activity was preceded in time by an increased CSA and IL-1 formation. Elevated IL-2 synthesis and increased T cell activation paralleled the peak in granulopoietic activity.

Aflatoxin B1↗
PubMed1992

Isolation of a metastasizing cancer cell line from an aflatoxin B1-induced rat liver tumor.

An attempt was made to isolate cancer cell lines from liver tumors that had been induced by aflatoxin B1 (AFB1) in rats. A clonal cell line named AFB-1 was isolated from a liver tumor that was histologically diagnosed as hepatocellular carcinoma. When AFB-1 cells were inoculated into the subcutaneous tissue at the dorsal region of syngenic animals, they metastasized from the site of inoculation into the abdominal cavity to form many tumor nodules throughout the serous membrane and metastatic foci in the kidney and pancreas. They also metastasized into the thoracic cavity to form metastatic foci in the lung. This is the first instance where a metastasizing AFB1-induced cancer cell line has been isolated.

Aflatoxin B1↗
PubMed1992

Alterations in the growth and cycling status of granulocyte-monocyte colony-forming units (CFU-GM) in rats injected single doses of aflatoxin B1.

To determine the toxic effect of aflatoxin B1 (AFB1) on granulopoiesis in vitro, cultures of myeloid progenitor cells for granulocytes and macrophages CFU-GM in semisolid agar medium were used to evaluate colony formation and tritiated thymidine suicide technique for analysis of cycling status of CFU-GM. Male Fischer rats, 5 to 6 weeks old, were given a single i.p. injection of 1 mg/kg or 0.1 mg/kg of AFB1 which were approximately 1/5 or 1/50, respectively, of LD50 dose of AFB1. The administration of either dose of AFB1 caused a significant reduction of the number of CFU-GM derived colonies on the first and the second day after injection. This reduction was followed by a strong enhancement in CFU-GM colony formation on the third day, and by restoration to the normal level on the fourth day. The increase in percentage of CFU-GM in S-phase preceded one day the peak in CFU-GM colony formation. The two different doses of AFB1 exerted similar effects on the growth and cycling status of CFU-GM. Our data outline an early suppressive effect exerted by AFB1 to the rat granulopoiesis in vivo.

Aflatoxin B1↗
PubMed1991

Effects of aflatoxin B1 on myelopoiesis in vitro.

The short-term cultures of mouse myeloid progenitor cells for granulocytes and monocytes, granulocyte-monocyte colony-forming units (CFU-GM) (CFU-GM assay) and mouse long-term bone marrow culture (LTBMC) were used to investigate the hemopoietic suppression caused by aflatoxin B1 (AFB1). A dose-related suppression of granulopoiesis in short-term bone marrow cultures was seen when the cultures were treated with 10, 5, 1, 0.5 and 0.1 micrograms of AFB1/ml. Two selected doses of AFB1 (5 and 0.5 micrograms/ml) considered to be highly and slightly suppressive in CFU-GM assay exerted a strong suppression of myelopoiesis in LTBMC when applied long-term. Short-term (2 h) exposure of LTBMC to 5 micrograms of AFB1/ml caused a small damage to the myelopoiesis detected in the non-adherent layer. Short-term exposure to 0.5 micrograms AFB1/ml was without any effect on myelopoiesis in LTBMC. The production of colony-stimulating activity (CSA) by an adherent layer of LTBMC was decreased on the second and fifth day after the short-term exposure to both doses of AFB1 and comparable with non-treated culture on the seventh day after the exposure. Presented results indicate that both short-term culture of CFU-GM and LTBMC can be used in the definition and the prediction of host toxicity of AFB1 to hemopoiesis. However, comparing these two in vitro systems, the LTBMC appears to be more sensitive and discriminatory in an evaluation of hemopoietic toxicity.

Aflatoxin B1↗
PubMed1991

Antifungal activity of fumaric acid in mice infected with Candida albicans.

An examination was made on the effect of fumaric acid on an experimental systemic candidiasis. Male ICR mice were innoculated into the tail veins with 10(6) yeast cells of Candida albicans and treated with daily intraperitoneal injections of fumaric acid at the dose of 40 mg/kg/d. The results indicated that the administration of fumaric acid was effective in prolonging the survival of animals after the fungal challenge and prevented one-fifth of the treated animals from dying of candidiasis.

Animals↗
PubMed1991

The mechanical properties and solubility of strontium-substituted hydroxyapatite.

The mechanical properties and solubility of sintered Sr-substituted hydroxyapatites were examined in order to investigate the influences of Sr incorporation into hydroxyapatite in bones and teeth on them. Hydroxyapatite (HAp), Sr-substituted hydroxyapatite (Ca.SrAp), and strontium-hydroxyapatite (SrAp) were synthesized and sintered. The bending strength and Young's modulus were measured. Also, solubility in isotonic NaCl solution was examined. The Young's modulus of Sr-substituted hydroxyapatite (Sr wt% = 1.0) and hydroxyapatite surface treated with Sr ion were greater than that of hydroxyapatite. The bending strengths of Sr-substituted hydroxyapatites (Sr/Ca = 4/6 and less) were reduced slightly compared to that of hydroxyapatite. The bending strength of hydroxyapatite surface treated with Sr ion was increased compared to that of hydroxyapatite. The solubility in isotonic NaCl solution at 37 degrees C was increased with an increase in Sr content. The effects of Sr on the mechanical properties and solubility of bones and/or teeth are discussed.

Biomechanical Phenomena↗