Search PubMed⌕ Search

Biomedical subjects

M Nagayama

Publications and source records attributed to M Nagayama.

At least 109 records · Page 6Linked to original sources
PubMed1991

Mineralized nodule formation in rat bone marrow stromal cell culture without beta-glycerophosphate.

Rat bone marrow stromal cells were cultured in the presence of 10 nM dexamethasone and various concentrations of beta-glycerophosphate. At day 12-15, some nodules consisting of polygonal cells were formed in all culture conditions, and these nodules were mineralized 2-3 days later. beta-Glycerophosphate significantly enhanced nodule formation at concentrations of not less than 5 mM. The mineralized nodules formed in the absence of beta-glycerophosphate were examined using phase-contrast microscopy, undemineralized and demineralized tissue histology, histochemistry for alkaline phosphatase, immunohistochemistry for type I, II, and III collagen, energy dispersive X-ray microanalysis, electron diffraction, and Fourier transform infrared spectroscopy (FT-IR). Mineralized nodules had histological characteristic similar to bone. Cells associated with nodules exhibited high alkaline phosphatase activity, and extracellular matrix of the nodules predominantly consisted of type I collagen. X-Ray microanalysis showed the presence of Ca and P in the mineralized area, and electron diffraction pattern showed the mineral to have apatite crystal structure. Moreover FT-IR indicated that the mineral was a mixture of hydroxyapatite and carbonateapatite. From these observations, it is concluded that the mineralized nodules formed in our culture system are truly bone-like.

Alkaline Phosphatase↗
PubMed1991

Behaviour of human ameloblastoma cells in collagen matrix in vitro: an ultrastructural study.

We investigated the behaviour of human ameloblastoma cells in collagen matrix in vitro. The ameloblastoma tissue was extirpated from a 75 yr-old woman. Small segments of the tissues were cultured in 0.18% collagen gel. After several weeks, collagen gels containing ameloblastoma tissue were fixed and examined by light microscopy and transmission electron microscopy. Outgrowth of primary cultured cells could be recognized as processes like growth rims around the tissue pieces within 2-3 days after tissue culture. Light microscopically, these cells formed a duct-like structure. The characteristics of ameloblastoma cells in vivo with peripheral epithelial cells and stellate cells reappeared in vitro, and they were connected with one another in cytoplasmic processes by desmosomes. Also, some cells had many intracellular filaments, amorphous nuclei and vacuoles. The results indicated that this culture system in vitro might be applied to the cytogenetic analysis of ameloblastoma.

Aged↗
PubMed1991

The behavior of human ameloblastoma tissue in collagen matrix in vitro: an immunohistochemical study.

We investigated the three-dimensional outgrowth of human ameloblastoma cells cultured in collagen matrix. Growth patterns of four cases of ameloblastoma resembled each other and was characterized by appeared duct-like structures. Case 1 ameloblastoma was subcultured 3 times. Ameloblastoma tissues and cultured cells were stained with various lectins by avidin-biotin peroxidase complex (ABC) staining methods. Both the tissues and cultured cells had the same receptors to Concanavalin ensiforme (Con A), Ricinus communis Agglutinin (RCA-I) and Triticum vulgaris (WGA) but not to Dolichos biflorus (DBA), Ulex europaeus (UEA-1), Soybean (SBA) and Arachis hypogea (PNA). These findings indicated that the cultured cells examined in this study were ameloblastoma cells in origin.

Adolescent↗
PubMed1991

Light- and electron-microscopic observations on the mandibular condylar cartilages in growing rats on a low-calcium diet.

In order to obtain more insight into the physiologic mechanism of endochondral ossification, histological changes occurring in the mandibular condylar cartilage of growing rats fed on a low-calcium diet were investigated by light and electron microscopy. Twenty-three-day-old rats were fed on a normal diet or a low-calcium diet for 8 weeks. For the histological observations the mandibular condyles were dissected from each animal at 1, 2, 4, 5 and 8 weeks after the initiation of the experiment. Histological changes occurring in the mandibular condylar cartilages of the rats fed on a low-calcium diet were as follows: (1) narrow proliferative and mature cell zones and a wide hypertrophic cell zone, (2) inhibition of development of cell organelles in the mature chondrocytes, (3) decrease in dead cells in the proliferative zone, (4) decrease in glycogen accumulation in the chondrocytes and (5) inhibition of calcification in the extracellular matrix of the hypertrophic cell zone. Additionally at the end of the experimental period, the following findings were observed: (1) appearance of small light cells in the mature cell zone and the hypertrophic cell zone and (2) decrease in proteoglycan granules and appearance of large collagen fibrils in the pericellular region of the hypertrophic cell zone.

Animals↗
PubMed1991

Ultrastructure of mineralized nodules formed in rat bone marrow stromal cell culture in vitro.

Rat bone marrow stromal cells were cultured in vitro. At days 14-15 of culture, dense clusters of polygonal cells were formed, and they mineralized 2-3 days later. The cells resembling osteoblasts or young osteocytes were histologically observed to be embedded in mineralized or unmineralized extracellular matrices of the nodules. Next, these mineralized nodules were electron-microscopically examined. The osteoblastic cells associated with the nodules had a well-developed rough endoplasmic reticulum, an evident Golgi apparatus and some mitochondria as their intracellular organellae. Some lysosomes and microfilaments were also visible in the cytoplasms. Moreover, some cells protruded cell processes toward the neighboring cells through the extracellular matrix. The extracellular matrix consisted of numerous collagen fibrils which were striated with 60-70 nm axial periodicity and which was similar to bone tissue collagen. A large number of matrix vesicles were scattered among the collagen fibrils in the unmineralized area of the nodules. In contrast, in the mineralized area, numerous matrix vesicles at different stages of maturation and many calcified spherules were observed. That is the mineralization in this culture system was considered to be initiated in association with the matrix vesicles and to progress along the collagen fibrils. From these findings, it was confirmed by the present study that the mineralized nodules formed in this bone marrow stromal cell culture were ultrastructurally similar to bone and that the mineralization also proceeded by going through the normal calcification process. This culture system is considered to be available to study osteogenic differentiation and calcification mechanisms.

Alkaline Phosphatase↗
PubMed1991

Effects of azamethiphos, an organophosphorus insecticide, on serum cholinesterase activity and isoenzymes in the rat.

The inhibitory effect of azamethiphos (Az), an organophosphorus insecticide, was detected in both the serum cholinesterase (ChE) activity and the ChE isoenzyme concentration in male Wistar rats. In our highest Az dosage group (270 mg/kg), following a single po administration, the serum ChE activity was significantly inhibited at 6 and 24 h post-Az administration. Five days after Az treatment, the ChE activity was still inhibited, but the observed difference was not statistically significant. The ChE activity increased to levels comparable to the control group by day 10. For the other Az-dosed groups, the ChE activities were inhibited only 6 h following administration. The serum ChE isoenzymes for all Az-dosed and control groups had 6 bands, indicating that Az did not effect the number of isoenzyme bands, indicating that Az did not effect the number of isoenzyme bands. However, Az had a significant effect on the ratios of the concentrations of these isoenzyme bands. The ratio of the main ChE isoenzyme bands (bands 5 and 6) was band 6 greater than band 5 for the young control group. As our control group aged, this ratio was reversed, with band 5 greater than band 6. For the highest Az dosage group (270 mg/kg), the ChE isoenzyme band ratio was band 5 greater than band 6 6 h after Az dosing. This proportion of band 6 decreased in parallel with an increase in band 5 during our 30-d experimental period. A correlation between the total ChE activity and ChE isoenzyme band 6 was found.

Animals↗
PubMed1991

[Blood flow changes on bathing in patients with myocardial infarction: studies by Doppler echocardiography].

We studied the influence of bathing on cardiac function and hemodynamics in patients with myocardial infarction (MI) using Swan-Ganz catheter, and using Doppler echocardiography noninvasive indices to assess the increase in pulmonary arterial pressure or pulmonary capillary wedge pressure during bathing were also studied. Fifty-four patients with MI (mean age 56.0 years) were examined (19 with extensive anterior MI, 13 with anterior, 17 with inferior and 5 with anterior and inferior MI). Bathing was conducted with patient in the supine position using tap water at 42 degrees C for 5 min in the Hubbard tank. The patients were classified into 2 groups; one with an increase in the pulmonary capillary wedge pressure (delta PCWP) above 10 mmHg (Group A), and the other with pressure below 10 mmHg (Group B). The hemodynamic data and echocardiographic indices such as peak velocities of blood flow (PV) at the right and left ventricular outflow tracts (RVOT and LVOT) and blood flow pattern at the left ventricular inflow tract (LVIT) were compared between these 2 groups using Doppler echocardiography. In Group A, extensive anterior MI was more frequent (p < 0.05). The exercise duration time was significantly short (6.3 +/- 1.6 min vs 10.2 +/- 2.8 min, p < 0.001) in the exercise tolerance test by bicycle ergometer. The left ventricular end-diastolic pressure was significantly high (17.8 +/- 8.2 mmHg vs 14.8 +/- 4.4 mmHg, p < 0.05) and the left ventricular ejection fraction was lower (39.8 +/- 19.6% vs 56.2 +/- 16.8%, p < 0.01) in cardiac catheterization. This indicated that they had cardiac dysfunction. In Group A, there were marked increases in pulmonary arterial pressure and right atrial pressure during bathing. PV at the RVOT was significantly increased in both Groups A and B (110.3 +/- 5.8%, 112.7 +/- 11.8%, both, p < 0.001). The ratio between 2 peak velocities (A and R) (A/R) at the LVIT in Group A was significantly increased compared with Group B (110.0 +/- 24.5% vs 98.1 +/- 14.5%, p < 0.01), while PV at the LVOT decreased significantly in Group A (92.0 +/- 14.6%, p < 0.01) and increased in Group B (115.0 +/- 17.7%, p < 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

[The effect of organochlorine compounds on the induction of sister chromatid exchanges in cultured human lymphocytes].

In this study, first, we investigated the effect of 7,8-benzoflavone (ANF), mitomycin C (MMC), a well-known genotoxic compound, and ANF plus MMC on the induction of sister chromatid exchanges (SCEs) in human whole-blood cultures. Second, we examined the effect of mixture of organochlorine compounds, which very resembled their contamination of healthy people in its composition, on the induction of SCEs in the same blood culture system in order to clarify their genotoxicity as a whole. The following results were obtained. 1. ANF and MMC significantly enhanced the number of SCEs/cell at the concentrations of 4 x 10(-5) M and 10(-8)M, respectively. When both of the compounds were simultaneously added in the blood cultures, their effects on the induction of SCEs seemed to be additive. 2. Without ANF in the blood culture system, namely, an usual system of the SCEs experiment, we could not find a dose-response relationship between the concentration of the mixture of organochlorine compounds and the induction of SCEs/cell. With ANF, however, we observed a fairly good dose-response relationship between them. 3. In the whole-blood culture system with ANF, we found significantly great number of SCEs/cell at the level of twenty times higher concentration of the organochlorine compounds than the ordinary level. According to the results described above and of our other studies, 50% effective concentration (EC50, about 2 SCEs/cell higher than control SCEs/cell) of the mixture was considered to be about 5 times greater level over the general one.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzofurans↗
PubMed1991

[Incidence of Chlamydia trachomatis isolated from endocervical columnar cells of the uterine cervix].

To study the incidence of Chlamydia trachomatis (C.T.) infection among women, we obtained swab (endocervical columnar cells) from the uterine cervix of 1,041 women attending the Department of Obstetrics and Gynecology of Gunma University Hospital. The results were as follows. 1) Overall, C.T. was isolated from 60 of the 1,041 women (5.8%). With reference to the diagnoses, the organism was isolated from 38 of 183 patients with cervicitis (20.8%) and from 22 of 858 asymptomatic womens (2.6%) (p less than 0.001). 2) C.T. antigen was detected at a higher frequency (15.0%) in the under 30 years age group than in the over 30 year age group (2.3%) (p less than 0.001). 3) The unstained inclusion C.T. bodies were confirmed more easily by phase contrast microscopy. 4) Inclusion bodies were specified as either reticulate or elementary bodies by the acridine orange staining method.

Adult↗
PubMed1990

Diketopiperazine-mediated peptide formation in aqueous solution.

Though diketopiperazines (DKP) are formed in most experiments concerning the prebiotic peptide formation, the molecules have not been paid attention in the studies of chemical evolution. We have found that triglycine, tetraglycine or pentaglycine are formed in aqueous solution of glycine anhydride (DKP) and glycine, diglycine or triglycine, respectively. A reaction of alanine with DKP resulted in the formation of glycylglycylalanine under the same conditions. These results indicate that the formation of the peptide bonds proceeds through the nucleophilic attack of an amino group of the amino acids or the oligoglycines on the DKP accompanied by the ring-opening. The formation of glycine anhydride, di-, tri- and tetraglycine was also observed in a mixed aqueous solution of urea and glycine in an open system to allow the evaporation of ammonia. A probable pathway is proposed for prebiotic peptide formation through diketopiperazine on the primitive Earth.

Amino Acid Sequence↗
PubMed1990

In vitro mineralization of osteoblastic cells derived from human bone.

Osteoblastic cells were isolated from human maxilla by embedding the bone pieces in collagen gel. The isolated cells could be maintained in monolayer culture up to 50 population doubling levels (PDLs). Both parathyroid hormone (PTH) and prostaglandin E2 (PGE2) increased intracellular cyclic AMP level of the cells. The cells also showed high level of alkaline phosphatase (ALPase) activity and formed mineralized areas in monolayer culture. Electron microscopy demonstrated that these cells were surrounded by numerous well-banded collagen fibrils, among which matrix vesicles were scattered. It was also observed that needle-shaped crystals protruded from some matrix vesicles. These protruded crystals appeared to deposit along the collagen fibrils and a mineralized matrix was formed. The minerals of mineralized matrix mainly consisted of calcium and phosphorus and had the same Ca/P ratio as hydroxyapatite. These results indicate that the cells derived from human bone have characteristics of osteoblastic cells.

Alkaline Phosphatase↗
PubMed1990

Effect of retinoic acid on proliferation and differentiation of cultured chondrocytes in terminal differentiation.

We obtained terminally differentiated chondrocytes in monolayer culture from chick embryonal growth plates, and examined the effect of retinoic acid on these cells. The cells treated with retinoic acid ceased type X collagen synthesis and showed decreased calcium incorporation into cell layers. Retinoic acid tended to stimulate proliferation of the cultured chondrocytes. It also increased DNA accumulation dose-dependently in the range from 1 nM to 1 microM. DNA synthesis in the growth phase and confluency was stimulated within 10 h after addition of 0.1 microM retinoic acid. [3H]Retinoic acid binding, which was inhibited by simultaneous addition of excess unlabeled retinoic acid, was detected in both the cytosolic and nuclear fractions of the chondrocytes. The retinoic acid binding capacity of the nuclear fraction was increased by pretreating the cells with retinoic acid. These results indicate that retinoic acid binds to both the cytosolic and nuclear fractions of cultured chondrocytes, and induces their proliferation and dedifferentiation.

Animals↗
PubMed1990

[An early cancer of the descending colon, histologically showing a poorly differentiated adenocarcinoma].

Reported is the case of a 71 year-old male with a poorly differentiated adenocarcinoma of the colon that had invaded the submucosal layer. A barium enema had revealed a polyp, 1.5 cm in diameter, in the descending colon, and an endoscopic polypectomy was performed. The resected specimen mainly consisted of an adenoma and a partial, poorly differentiated adenocarcinoma that had massively infiltrated into the submucosal layer. A left hemicolectomy was carried out, and no carcinoma was identified in the resected colon and/or the regional lymph nodes.

Adenocarcinoma↗
PubMed1989

Fat emulsion in surgical patients with liver disorders.

Total parenteral nutrition (TPN) with fat emulsion was evaluated in 68 patients with liver disorders who were admitted to the First Department of Surgery, Osaka City University Medical School. All patients received transabdominal direct operation for esophageal varices. Immediately after their operations, 28 received TPN with carbohydrate and fat emulsion as an energy source (FAT group), and 40 received TPN with only carbohydrate as an energy source (non-FAT group). Liver function tests, blood glucose levels, intravenous fat tolerance tests, serum lipid levels, fatty acid composition of serum total lipids, and nitrogen balance of the two groups were compared during postoperative TPN. The administration of fat emulsion during postoperative TPN in patients with liver disorders did not worsen the results of liver function tests and the relatively low levels of blood glucose were retained, thereby correcting the abnormalities in the fatty acid composition of serum total lipids. Rates of clearance of fat emulsion during postoperative TPN were significantly higher than in the preoperative period, and changes in serum lipid levels revealed no tendency toward retention of fat emulsion administered intravenously. Nitrogen balance and change in body weight during postoperative TPN were similar in both groups. These results suggest that for patients with liver disorders, the administration of fat emulsion is useful during postoperative TPN.

Esophageal and Gastric Varices↗
PubMed1989

[Productive aspergilloma on the inner wall of a cavity].

Fungus ball type pulmonary aspergilloma is easily recognizable on chest X-ray. This is a report on "productive aspergilloma on the inner wall of a cavity" (PAIC), named from our clinical experience in 1980, which grew to form aspergillus strata on partial or overall inner walls of the cavity. Our 5 cases with this type supported the existence of this type and revealed an 18% incidence in patients with pulmonary aspergilloma, characteristic clinical features and immunological reactions, thus pointing to the necessity of early diagnosis and treatment for this type of aspergilloma. The species of aspergillus cultured from the patients with this type of disease was Aspergillus fumigatus.

Adult↗
PubMed1989

[Effects of salivary ultrafiltrates on the production of phenol from tyrosine by oral microorganisms].

The metabolism of oral microorganisms is known to correlate with oral diseases. Protein degradation by oral microorganisms is usually followed by the production of phenol from tyrosine. The purpose of this study is to clarify the effect of salivary ultrafiltrates [MW: less than 10,000, 1,000-10,000 (intermediate fraction), less than 1,000, less than 500] on the production or the decomposition of phenol by oral microorganisms. Salivary sediment and salivary ultrafiltrate, the molecular weight of which is less than 10,000 unless otherwise stated, were incubated at 37 degrees C for 24 hours with tyrosine or phenol at a final concentration of 2.5 mg/100 ml. After incubation, the phenol produced (or remained) was extracted with ether and determined spectrophotometrically. Phenol production by oral microorganisms was not seen in the non-dialyzable fraction of saliva even when tyrosine was added. It was confirmed that the presence of the salivary ultrafiltrates was essential for the production of phenol by oral microorganisms. Phenol production in the salivary ultrafiltrate was further increased with the addition of tyrosine or non-dialyzable fraction of saliva. Phenol disappeared within 48 or 72 hours after the salivary sediment was incubated with phenol. The decomposition of phenol was inhibited with the salivary ultrafiltrate. Phenol production was enhanced with the addition of Good's buffer. Optimum pH of phenol production by oral microorganisms in the ultrafiltrate of saliva was within the range from 6.5 to 7.0 in the presence of Good's buffer (MOPS). Phenol production decreased with the reduction of the molecular weight of the salivary ultrafiltrates. The phenol production was increased when the intermediate fraction was added to the ultrafiltrate (MW: less than 1,000). The increase of the phenol production was considered to be due to the peptides in the intermediate fraction.

Bacteria↗