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Y Inayama

Publications and source records attributed to Y Inayama.

69 records · Page 4Linked to original sources
PubMed1990

Pathways of differentiation of airway epithelial cells.

The question being examined is whether one or more morphologically distinct cell types can be identified in the conducting airways of adult rabbits possessing stem cell functions. The term "stem cell" is used to denote cells with extensive self-replicating potential and the ability to produce differentiated progeny. According to various models of cell renewal in the conducting airways that have been proposed over the years, two different cell types have to be regarded as primary candidates for the stem cell: basal cells and some type of secretory cells. The question is complicated by the fact that significant differences exist between species in the distribution and morphological characteristics of airway cell types. In addition, different airway segments may or may not be occupied by different populations of stem cells. Previously, investigators have addressed the problem by studying normal cell regeneration or injury induced cell regeneration in vivo in the whole animal. We decided to attempt a different approach, namely, to separate specific cell types and to study the proliferation and differentiation capacity of such cell isolates using in vitro and in vivo cell culture techniques. Our studies lead us to conclude that the conducting airways of adult rabbits contain at least two distinct cell populations endowed with stem cell potential, namely basal cells and bronchiolar Clara cells. From that it follows that the trachea and bronchi, on one hand, and the bronchioles, on the other hand, are occupied by two different stem cell populations governing renewal of the epithelial lining.

Animals↗
PubMed1990

The detection of normal hidden stem cells during the development of leukemia: assays with PGK isozyme.

We evaluated the changes in the number of normal spleen colony-forming units (CFU-S) in the spleen and the bone marrow of C3H/He mice during the development of leukemia following the injection of the murine leukemia cell line, MK-8057, MK-8057 cells, originating in C3H/He PGK-1b mice, were injected into syngeneic C3H/He PGK-1a mice so that phosphoglycerate kinase (PGK) isozymes could be used to distinguish leukemic spleen colonies from normal colonies when cells from the spleen or bone marrow of the recipients were reinjected into lethally irradiated mice. Leukemic cells showed a logarithmic increase in the recipient mice and had replaced the bone marrow and the spleen completely by days 6-8; the mice started to die of leukemia after day 11. However, colonies examined from normal stem cells still comprised 60% of the total number of spleen colonies on day 6, 45% on day 8, and 20% on day 10. Furthermore, when the numbers of normal CFU-S were calculated as numbers per spleen, we found that they increased exponentially to a level 100 times higher than the normal level 10 days after injection of MK-8057 cells.

Animals↗
PubMed1990

Long-term maintenance of human distal airway epithelial cells in nude mice: a potentially useful model for the study of pulmonary carcinogenesis and lung cell biology.

We investigated whether the normal morphology of distal airway epithelial cells from adult human lungs could be maintained for long periods of time as xenografts in nude mice. Peripheral lung tissue obtained from normal regions of lungs resected for lung cancer was transplanted subcutaneously into nude mice. The implants were then retrieved at intervals from 2 to 26 weeks for light and electron microscopy, and for immunohistochemical examination. At 2 weeks, revascularization of the implants and replication of immature epithelial cells were observed. At 4 weeks and thereafter, the epithelium formed in the implants was almost mature and normal in appearance. Pseudostratified columnar epithelium composed of ciliated, mucus, and basal cells lined the larger airspaces, whereas the smaller airspaces including alveolar structures were generally lined with type II pneumocytes and occasionally with Clara cells. Normal alveoli with type I pneumocytes and capillary networks were rarely observed. The implants were maintained in the nude mice for as long as 26 weeks. Cytokinetic studies of the epithelial cells in the implants using immunocytochemical detection of incorporated bromodeoxyuridine revealed that an inverse relationship existed between the degree of maturation and the replicative capacity of the epithelial cells. It was also found that, even in the mature epithelium, a small fraction of the cells were undergoing DNA synthesis. Peripheral lung tissue xenografts in nude mice may provide an excellent in vivo model for the study of pulmonary carcinogenesis and also for the study of both the function and differentiation of human epithelial cells of the distal airways.

Animals↗
PubMed1990

Growth and differentiation of human distal airway epithelial cells in culture. Effects of small amounts of serum in defined medium.

We herein describe a new simple method for culturing primary epithelial cells derived from the distal airway of adult human lung. Peripheral lung tissue obtained from surgical materials was cultured as explants in Ham's F12 medium supplemented with hormones and growth factors. From days 10 to 14, outgrowth of epithelial cells started on the dish surface, and even after removal of explants at days 14 to 16, these cells continued to replicate during the 3rd and 4th week of culture, and eventually formed epithelial cell foci (10 to 20-fold increase in population). They then ceased to replicate and terminally differentiated in the 5th week. Addition of 1% serum to the culture medium enhanced the initial outgrowth of epithelial cells, whereas small amounts of serum had no effect on proliferation of cells after explant removal. On the other hand, serum modulated the differentiation phenotypes of epithelial cells. In the presence of 1% serum, numerous ciliated and secretory cells appeared, whereas the cells underwent epidermoid differentiation in the absence of serum. When replated onto 3T3 fibroblast feeder layers, the epithelial cells from earlier cultures showed a great replicative capability and formed colonies at higher frequencies (colony-forming efficiency, 8 to 27% at days 14 to 21), but the replicative capability was significantly reduced at the confluent stage (colony-forming efficiency, 0.44 to 2.0% at day 28). Morphologic examinations of explants strongly suggested that the primary cells were derived from the bronchiolar epithelium. We conclude that this new culture system provides an excellent model for studying the growth, differentiation, and function of human bronchiolar epithelial cells in vitro.

Bronchi↗
PubMed1990

[Non-neuroectodermal epithelial cyst in the middle cranial fossa associated with unilateral exophthalmos].

A rare case of unilateral exophthalmos caused by an epithelial cyst in the middle cranial fossa was reported. A 42-year-old man had a proptosis of sudden onset in the left eye. Ophthalmological examinations revealed a proptosis of 3mm, contraction of the lower visual field and a bow tie atrophy of the optic disc in the left. Plain skull X-P, CT scan and MRI disclosed a cystic lesion in the left middle fossa, resulting in the enlargement of the superior orbital fissure of the same side. Metrizamide CT cisternography showed the cyst had no communication with the subarachnoid spaces. The cyst, removed surgically, was located in the epidural region of the middle fossa and was about 4cm in diameter, containing yellowish turbid fluid and fat-like floating substance. Histologically, the cyst was composed of collagenous connective tissue, lined with pseudostratified columnar to cuboidal epithelia. Small cells with a high nuclear to cytoplasmic ratio, considered as basal cells or reserve cells, were often seen in the basal layer. Ciliated and secretory cells were rarely observed in the superficial layer. Neither stratified squamous epithelium nor adamantinomatous structure was seen. Immunohistochemical studies revealed that the lining epithelium was strongly positive for keratin (wide spectrum), but negative for vimentin, S-100, neuron specific enolase or glial fibrillary acidic protein. These staining characters were different from those of neuroectodermal cells including ependymal cells and choroidal cells which are usually vimentin- and S-100-positive. Morphologically, the lining epithelium resembled respiratory or alimentary tract epithelium, suggesting that the cyst might be derived from non-neuroectodermal ectoderm or endoderm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

In vitro and in vivo growth and differentiation of clones of tracheal basal cells.

Studies were performed to examine the hypothesis that the basal cells in the large conducting airways function as stem cells. Basal cells were isolated from the tracheas of adult rabbits using centrifugal elutriation procedures. Such cell isolates that contained greater than 90% basal cells were plated in culture at low cell density to produce individual basal cell clones. Clones were similarly obtained from unfractionated tracheal cells (mixed tracheal cells). Basal cell and mixed cell clones were tested to compare their in vitro growth capacity and their ability to reepithelialize denuded tracheal grafts with a mucociliary epithelium. Both basal cell and mixed cell clones underwent 15 to 20 population doublings in culture. The sizes of their clonogenic cell compartments were roughly similar. When inoculated into denuded tracheal grafts, both types of clones were equally efficient in establishing a mucociliary epithelium. The major secretory cell types observed in tracheas repopulated with the two types of cell clones were cells containing small secretory granules and either rough or smooth endoplasmic reticulum. Goblet cells were seen in approximately 40% of tracheas repopulated with either of the two types of cell clones. It is concluded that in rabbits tracheal basal cells can generate secretory cells with varying morphologic characteristics as well as ciliated cells and may be regarded as epithelial stem cells.

Animals↗
PubMed1988

Pulmonary adenoma and endocrine cell hyperplasia in Syrian golden hamster treated with 4-nitroquinoline 1-oxide.

Chronic effects of 4-nitroquinoline 1-oxide (4 NQO) on the lungs of Syrian golden hamsters were studied. 4 NQO was subcutaneously injected weekly for 3 weeks at a dose of 20 mg/kg body weight. The animals were sacrificed at the 65th and 80th experimental weeks. Two cases of pulmonary adenomas were demonstrated in the 10 4 NQO-treated animals at the 80th week, and the tumor cells contained cytoplasmic lamellar inclusion bodies. In a previous study, we reported 4 NQO- induced pulmonary endocrine cell hyperplasias in the 4 NQO-treated hamster after the 20th experimental week (Jpn. J. Cancer Res., 77, 1986). In the present study, 12 pulmonary endocrine cell hyperplasias were recognized in serial sections of the 24 treated animals. The hyperplastic lesions showed positive immunoreactivity to calcitonin. The hyperplastic lesion did not develop to pulmonary endocrine cell neoplasm.

4-Nitroquinoline-1-oxide↗
PubMed1988

The differentiation potential of tracheal basal cells.

The objective of this study was to examine the differentiation potential of basal cells purified from rabbit tracheas by means of centrifugal elutriation. Cell suspensions containing between 83 and 94% basal cells were inoculated into tracheal grafts denuded of their own epithelium and transplanted to the backs of nude mice. Within 1 week after inoculation, the basal cells reestablished a continuous poorly differentiated epithelial sheet which at 2 to 4 weeks showed typical mucociliary differentiation. Basal cells, ciliated cells, goblet cells, and secretory cells with small granules were present. Some of the latter contained abundant rough endoplasmic reticulum and others contained predominantly smooth endoplasmic reticulum. These data indicate that basal cells can give rise to all major tracheal cell types suggesting that they are the main stem cell in the large airways of rabbits.

Animals↗
PubMed1987

Morphologic alteration of mouse Clara cells induced by glycerol: ultrastructural and morphometric studies.

In our studies on activation of the Clara cell by biological substances and its relationship to pulmonary carcinogenesis, we found that large doses of glycerol induced drastic morphologic changes selectively in the Clara cell among distal airway epithelial cells in ddY mice. Subcutaneous injection of glycerol (7.2 g/Kg body weight) caused cytoplasmic edema with disruption of endoplasmic reticulum membranes at 1 and 3 hours, followed by hyperplasia of smooth endoplasmic reticulum (SER) at 12 and 24 hours. Concentric lamination of SER was observed at 48 and 96 hours. Oral administration of 5% glycerol in drinking water for 2 to 8 weeks induced more conspicuous hyperplasia and hypertrophy of SER in the Clara cells. Electron microscopic morphometry revealed a 3-fold increase in the profile area of SER in the Clara cells of the animals at 2 and 8 weeks. Both the profile area and the number of secretory granules increased significantly at 2 and 8 weeks, and those of mitochondria tended to increase with time of glycerol treatment. In both experiments, the mitochondria of the Clara cells exhibited marked elongation and distortion of the contour associated with appearance of prominent cristae. These results suggest that large doses of glycerol induce marked alteration in the functional activity of the mouse Clara cell.

Animals↗
PubMed1986

Effects of glycerol on 4-nitroquinoline 1-oxide induced pulmonary tumorigenesis in ddY mice.

The effects of glycerol administration on pulmonary tumorigenesis induced by 4-nitroquinoline 1-oxide (4NQO) were examined in male ddY mice, that were given 5% glycerol solution instead of drinking water after a subcutaneous injection of 4NQO. The incidence of pulmonary tumor-bearing mice and the mean number of induced tumors per mouse were significantly enhanced in mice given glycerol after 4NQO treatment, compared with mice given 4NQO alone. The results demonstrate effects including that of promotion by glycerol in 4NQO-induced pulmonary tumorigenesis.

4-Nitroquinoline-1-oxide↗
PubMed1986

Promoting action of glycerol in pulmonary tumorigenesis model using a single administration of 4-nitroquinoline 1-oxide in mice.

This study was carried out to clarify the promoting effect of glycerol on 4-nitro-quinoline 1-oxide (4NQO) tumorigenesis in the lung. Animals used were 80 ddY male mice, 6 weeks old. 4NQO, dissolved in olive oil-cholesterol (20:1) mixture, was injected subcutaneously at a dose of 10 mg/kg body weight per mouse. Drinking water contained 5% glycerol. Mice were divided into the following 4 groups of 20 animals each: non-treated mice (group I), mice given glycerol alone (group II), mice given 4NQO alone (group III), mice receiving combined administration of 4NQO and glycerol (group IV). The percent of mice having induced pulmonary tumors and the mean number of tumors per mouse were 2 and 0.10 +/- 0.07 (mean +/- SE), 2 and 0.10 +/- 0.07, 9 and 0.45 +/- 0.25, and 58 and 2.90 +/- 0.62, respectively. A significantly higher rate was seen in group IV, as compared with the 4NQO-treated control. This result showed that glycerol has a promoting action on 4NQO-induced pulmonary tumorigenesis in mice.

4-Nitroquinoline-1-oxide↗
PubMed1986

4-Nitroquinoline 1-oxide-induced pulmonary endocrine cell hyperplasia in Syrian golden hamster.

The tumorigenic effects of 4-nitroquinoline 1-oxide (4NQO) on the hamster lung were examined by light and electron microscopy. The hamsters received three subcutaneous injections of 4NQO at a dose of 20 mg/kg body weight at weekly intervals, and were sacrificed at 20, 25, and 30 weeks after the first injection. Hyperplastic endocrine cell lesions were consistently demonstrated in the airway from the lobar bronchi to the bronchiolo-alveolar junctional area by serial sectioning of lung tissue slices of all the treated animals. The hyperplastic lesions contained argyrophilic cells and showed weakly positive immunoreactivity to neuron-specific enolase. Ultrastructurally, some of the cells contained small cored dense granules.

4-Nitroquinoline-1-oxide↗
PubMedDate not supplied

Lack of point mutation of the APP gene in sporadic Alzheimer's disease in Japanese.

We investigated point mutations of the APP gene in 66 patients with sporadic Alzheimer's disease (AD) and 180 normal individuals by use of the PCR (polymerase chain reaction) method. Both the AD patients and the normal individuals were Japanese. We extracted DNA from blood samples using the phenol-chloroform method and amplified exons 16 and 17 of the APP gene by PCR. PCR products were digested by MBO-II (exon 16) and BCL-1(exon 17). Electrophoresis was carried out with 3% agarose gel and the separated fragments were stained with ethidium bromide. In addition we investigated other point mutations of exons 16 and 17 by use of the PCR-SSCP (single stranded conformation polymorphisms) method, and found no fragments that exhibited point mutations in the AD patients and normal individuals. These findings indicate that the presence of point mutation of the APP gene is not a major cause of AD in the Japanese population.

Aged↗
PubMedDate not supplied

Crush and imprint cytology of subependymoma: a case report.

BACKGROUND: There are few descriptions of the cytologic features of subependymoma because this neoplasm is rare and most commonly encountered incidentally at autopsy. Here we report a surgical case of subependymoma occurring in the lateral ventricle and provide the first documentation of the crush cytologic features of this tumor. CASE: A 34-year-old woman was found to have a tumorous lesion in the right lateral ventricle. At surgery, a 2-cm-diameter tumor was detected in the anterior horn. Histologic examination during surgery revealed that the mass was composed of loose,fibrillary networks and clusters of nuclei showing mild pleomorphism. A number of microcystic formations were evident. Histologically, the neoplasm was considered benign--specifically, a subependymoma. Papanicolaou- or Giemsa-stained crush specimens and imprint smears were also prepared. The cytologic morphology was fundamentally the same as the histologic. In the crush specimens, microcystic formations were readily visible. Moreover, details of the cellular morphology were more easily recognized in the cytologic slides than in the frozen sections. CONCLUSION: Cytologic examination, particularly crush cytology, appears to be useful for the rapid diagnosis of subependymoma during surgery in combination with the examination of frozen histologic sections.

Adult↗