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Biomedical subjects

Y Ohashi

Publications and source records attributed to Y Ohashi.

At least 505 records · Page 28Linked to original sources
PubMed1991

Cooperative enhancement of hyaluronic acid synthesis by combined use of IGF-I and EGF, and inhibition by tyrosine kinase inhibitor genistein, in cultured mesothelial cells from rabbit pericardial cavity.

We examined the combined effects of IGF-I and EGF on hyaluronic acid synthesis using cultured pericardial mesothelial cells from rabbit pericardial cavity. Combined exposure of pericardial cells to IGF-I and EGF cooperatively increased hyaluronic acid synthesis and the level of hyaluronic acid synthase activity over that seen with or without IGF-I or EGF alone, but did not significantly stimulate the sulfated glycosaminoglycan synthesis. Increase in the level of hyaluronic acid synthesis and hyaluronic acid synthase activity induced by these growth factors was blocked after pretreatment with a tyrosine-specific protein kinase inhibitor, genistein. Genistein had no direct inhibitory effect on hyaluronic acid synthase activity. These results suggest that cooperative enhancement of hyaluronic acid synthesis induced by combined use of IGF-I and EGF could be mediated by a receptor tyrosine kinase-involved transmembrane signaling process that is responsive to IGF-I and EGF.

Animals↗
PubMed1991

A histochemical study of the development of premaxilla and maxilla during secondary palate formation in the mouse embryo.

The development of premaxilla and maxilla in the mouse fetus during secondary palate formation from the 12th to the 16th days of gestation was histochemically assessed. To determine the developmental stages, a classification based on the morphogenesis of the limbs, or the "limb score" (LS) was employed. The stage of LS coincided with the gestational age from the 13th to the 15th days. Early on the 12th day, alkaline phosphatase (ALPase) activity was intense in the mesenchyme lateral to the incisor tooth bud and latero-inferior to the inferior orbital nerve. Subsequently, osteoblasts differentiated at these two sites. The ALPase positive area grew concomitantly with the nasal capsule, the molar tooth germ, and the closure of the secondary palate. The area of bone differentiation contoured the orbital nerve and extended to the rostral part of the secondary palate. At the LS stage -6 (13.52 days), ALPase activity was observed in the mesenchyme medial to, and also surrounding the molar tooth germ. The area of osteogenesis of the secondary palate spread along the medial side of the molar tooth germ, where the formation of the medial alveolar process of the maxilla was completed by the LS stage 3 (15.35 days). The ALPase positive area extended to the horizontal palatal shelves. By late on the 16th day, the palatal process was fully developed. In parallel, bone resorption began on the molar side of the alveolar process. Acid phosphatase and tartrate-resistant acid phosphatase activities (ACPase and TRACPase activity, respectively) revealed ACPase and TRACPase positive mononuclear cells around the molar tooth germ long before ossification occurred. Our results thus suggest an involvement of the incisor tooth bud and the infra-orbital nerve in the initial osteogenesis of the premaxilla and maxilla. Enzyme activities lead to the consideration that osteoclast precursors initiate differentiation around the molar tooth germ. Ostensibly, the mechanical force from the growth of the molar tooth would promote differentiation and activation of osteoclasts located on the alveolar process. Also, the LS classification would improve and simplify future studies of the development of the secondary palate.

Acid Phosphatase↗
PubMed1991

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae. Mucociliary pathology of the eustachian tube.

Otitis media with effusion (OME) is generally benign and self-limiting but is often recurrent and can change into a chronic type. We have previously reported that intratympanic inoculation of lipopolysaccharide (LPS) from Klebsiella pneumoniae can develop experimental OME in the guinea pig. However, OME induced by 10 micrograms/ml of LPS was of a self-limiting type. Our hypothesis was that a higher concentration of LPS might develop a chronic OME because LPS reduces the ciliary activity in the tubotympanum in a dose related manner. In our present study we inoculated 100 micrograms/ml of LPS from K. pneumoniae into the tympanic cavity of the guinea pig, in the hope of illuminating a possible mechanism predisposing to the chronicity of the disease. A longer-term OME was observed after tympanic inoculation of 100 micrograms/ml of LPS. Ciliary activity in the Eustachian tube was depressed for a longer term by this dose than by the previous one. In addition to mucociliary pathologies and general inflammatory changes similar to those induced by 10 micrograms/ml of LPS, intracytoplasmic ciliary cysts were observed after inoculation of 100 micrograms/ml of LPS, which appeared to show disturbed ciliogenesis and chronic mucociliary lesions. In conclusion, intratympanic inoculation of a higher concentration of LPS developed a longer-term OME in the guinea pig, which was supported by functional as well as morphological examinations.

Animals↗
PubMed1991

Histamine-induced mucociliary dysfunction and otitis media with effusion.

Histamine, which has been found in middle ear effusions, is a potent pharmacological mediator released at an early stage of allergic reactions or general inflammatory process, increasing permeability of small blood vessels. Histamine might be involved in the origin and chronicity of middle ear effusions. In this study we studied the effect of histamine on the mucociliary function. First we examined the effect of histamine and its H1 and H2 blockers on the ciliary activity in the middle ear. 10(-2) M of histamine deteriorated ciliary activity; however, at lower concentrations ciliostimulatory effects were demonstrated for histamine (between 10(-8) M and 10(-4) M). Such ciliostimulatory effects were not affected by diphenhydramine (H1-blocker) but were reduced by cimetidine (H2-blocker). Thus histamine stimulates ciliary activity by combining with H2-receptor. Intratympanic injection of 10(-4) M of histamine induced accumulation of middle ear effusions (MEEs). The volume of MEEs was largest at 1 day postinjection when its mucociliary clearance time was longest. Then the mucociliary clearance time became shorter, but it was still significantly longer than that of the control animal. Ciliary activity in the tubotympanum showed no recovery through the observation period. On the other hand, intratympanic injection of 10(-6) M of histamine produced MEEs at 1 and 3 days postinjection when the mucociliary clearance time was longer than that of the control group. At 8 days, when most ears did not demonstrate MEEs, the mucociliary clearance time and ciliary activity in the Eustachian tube and tympanic orifice reached the level of the control group. Our present study demonstrates that histamine can induce mucociliary dysfunction of the tubotympanum resulting in middle ear effusions, and that cilia, especially those present in the tube and the tympanic orifice, have a significant role in eliminating middle ear effusions.

Animals↗
PubMed1991

Influenza A virus-induced otitis media and mucociliary dysfunction in the guinea pig.

There is much epidemiologic, clinical and laboratory evidence that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated any direct influence of viruses on the tubotympanum. The purpose of this study was to establish the effect of influenza A virus having invaded the tubotympanum and so elucidate the possible mechanism by which this virus contributes to the pathogenesis of OME. Eighty guinea pigs with normal otoscopic findings were inoculated with 0.2 ml suspension of influenza A (3.3 x 10(8) PFU/ml) into the tympanic cavity through the tympanic membrane. To serve as controls, the same number of guinea pigs were injected with 0.2 ml of physiologic saline solution into the tympanic cavity. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions as well as mucociliary dysfunction were observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the Eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the controls. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the controls. The mucociliary clearance time of the tubotympanum was more prolonged than that of the controls at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphological changes were observed in the tubotympanum treated with the virus. Major pathologies observed included general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and newly formed centrioles. However, the viral infection also affected the epithelial cells with new centrioles. Our study demonstrates that viral infection can evoke mucociliary dysfunction of the tubotympanum and create increased susceptibility to bacteria. Therefore, viral infection may enhance bacterial infectious processes in the tubotympanu thereby contributing to the occurrence of OME.

Animals↗
PubMed1991

Current concepts of mucociliary dysfunction in otitis media with effusion.

From a survey of the literature on mucociliary function in the tubotympanum, it is clear that mucociliary activity and ciliary activity are deeply involved in the pathogenesis, pathology, and prognosis of otitis media with effusion. Ciliary function in the middle ear, especially in the tympanic orifice and the Eustachian tube, has an important role in the mucociliary clearance of surplus secretion to the pharynx. Our review demonstrates that ciliary activity in the tubotympanum is sensitive to a variety of pathological agents including bacteria, bacterial endotoxin, irritant gases, and irradiation, resulting in mucociliary dysfunction of the tubotympanum.

Animals↗
PubMed1991

Ciliary activity in the tubotympanum during type I allergic reaction.

The immune system is active in the tubotympanum and some middle ear diseases might be partially or exclusively immunologically mediated. However, the effect of an allergic reaction on the tubotympanic cilia remains to be elucidated. The response of normal tubotympanic cilia from the guinea pig was investigated in an in vitro experimental system to evaluate ciliary responsiveness without the influence of secretions. Mucosal samples were obtained from three different tubotympanic locations (Eustachian tube, and middle ear close to the tube (proximal site) and more distal to the tube (distal site)). Each mucosal sample was cultured in 2 ml of RPMI 1640 and 1 ml of heparinized venous blood from a nonallergic human subject, a patient with ragweed-sensitive nasal allergy, or 3 patients with Dermatophagoides farinae-sensitive nasal allergy. One microgram of D. farinae extracts was added in each chamber to evoke an in vitro allergic reaction, and the ciliary activity of the most active cell in each culture was monitored for up to 120 min. When D. farinae extracts were added into the chamber containing blood from subjects without sensitivity to D. farinae, no changes were induced in ciliary activity throughout the examination. When the same dose of allergens was added into the chamber containing blood from D. farinae-sensitive subjects, ciliary excitation was induced in the culture from the Eustachian tube and the proximal site. The peak and plateau of this phenomenon were observed at 30-40 min after the addition of the allergen, and a gradual slowdown to the baseline level was observed after the plateau. No ciliary depression was induced by an allergic reaction in the culture from the Eustachian tube or the proximal site. Such ciliostimulatory effects were correlated with D. farinae induced-percent histamine release from whole blood. In the cultures from the distal site, however, a gradual ciliodepression followed the peak of ciliary excitation. In conclusion, an in vitro allergic reaction affected the ciliary activity in the distal site, but such ciliary dysfunction was not observed in the Eustachian tube or the proximal site during such a reaction.

Animals↗
PubMed1991

Regeneration of nasal mucosa following mechanical injury.

Nasal mucosa is a subject of surgical operation for patients with nasal disorders. However, our knowledge about the regeneration of nasal mucosa after such a mechanical injury is still limited. In this study we investigated the recovery or regenerative process of nasal mucosa in rabbits after mechanical injury on the basis of ultrastructural as well as functional observations. Complete recovery of nasal mucosa was obtained in 5 days if the basal cells and basement membrane were intact. When the total layer of nasal mucosa was injured mechanically, regenerative stratified epithelium covered the defect in 1 week, new ciliated cells appeared in 3 weeks, and complete regeneration was observed at 6 weeks. At 3 weeks when the first appearance of cilia was observed, the beating activity of the cilia was in the normal range. In conclusion, we observed a great regeneration ability following mechanical injury in the nasal mucosa. The process of regeneration in the nasal mucosa after mechanical injury appears to depend on whether the basal cells and basement membrane are intact or not.

Animals↗
PubMed1991

Whole blood histamine release rate during immunotherapy for nasal allergy.

In treating nasal allergies, desensitization is widely used on a daily basis, and its efficacy has been highly valued. With the purpose of predicting therapeutic efficacy before carrying out immunotherapy, we compared whole blood histamine release rate and various subjective symptoms before and after immunotherapy. We also compared the degrees of efficacy. Immunotherapy brought about a tendency for a reduction in the whole blood histamine release rate. This tendency appeared most marked in those patients in whom an improvement of subjective symptoms was considerable. Among subjective symptoms, the reduction in whole blood histamine release rate was strongest against nasal discharge and sneezing. In patients with a low histamine release rate prior to the initiation of immunotherapy, the improvement in subjective symptoms tended to be low.

Adolescent↗
PubMed1991

RAST in diagnosis and therapy of allergic rhinitis.

Skin tests, RAST, nasal provocation tests, and other nasal allergy examinations were performed on 463 patients exhibiting symptoms of allergic rhinitis who were examined at the Department of Otolaryngology of Osaka City University Medical School, and comparisons were made between the RAST scores and the results of the other examinations. A study was also made of the change in grade of the allergic rhinitis and the change of the RAST score resulting from one year of immunotherapy. The rates of agreement for patients with positive skin test and RAST were 60 to 70% for house dust (HD), house dust mites, Japanese cedar, and cocksfoot, and 10 to 35% for common ragweed and the fungus group. The RAST was positive for house dust 1, house dust 2, and Dermatophagoides farinae in 80 to 90% of the patients with house dust or house dust mite allergic rhinitis, and for over 80% of the patients with pollinosis (Japanese cedar or common ragweed). In most cases, the RAST scores were unchanged by one year of specific hyposensitization, and in the cases in which the RAST scores did change, the treatment was ineffective.

Desensitization, Immunologic↗
PubMed1991

Colchicine-induced ciliated vacuoles in tracheal mucosa.

In most cells the microtubules are destroyed and disappear after administration of colchicine in concentrations as low as 10(-6) M; colchicine inhibits the polymerization of tubulin and destroys the microtubules. Ciliary microtubules have resistance to colchicine but can, on the other hand, be destroyed by high concentrations of colchicine. In this study, we treated rabbits with considerably high concentrations (10 or 20 mg/100 g body weight) of colchicine for four successive weeks and examined the effects on the tracheal cilia. Abdominal administration of colchicine did not affect the morphology and structure of the cilia projecting on the cellular surface. However, ciliated vacuoles were observed in tracheal epithelial cells of rabbits treated with colchicine. The occurrence of such ciliated vacuoles depended on the dosage of colchicine: 2.4 +/- 0.4 per 100 microns epithelial length when treated with 10 mg/100 g body weight of colchicine, and 3.8 +/- 0.3 per 100 microns epithelial length when treated with 20 mg/100 g body weight. Some cilia present in ciliated vacuoles were pathological. In conclusion, a considerably high dosage of colchicine can inhibit ciliary microtubules during ciliogenesis, resulting in ciliated vacuoles.

Animals↗
PubMed1991

An analysis of the subpopulations in draining lymph node cells and MHC antigen induction in murine herpetic keratitis.

The protective role of T cell subsets in corneal herpes simplex virus type 1 (HSV-1) infection has been studied. However, the relative contribution of, and the role played by, each particular T cell subset still remain a controversial issue. We studied sequentially the appearance of major histocompatibility (MHC) and viral antigens in HSV-1 infected corneas of Balb/C mice and related them to induction of T cell subsets in local lymph nodes and corneal lesions. Immunohistochemical study has revealed a marked increase of expression of class II MHC antigen in the corneal stromal cells, while class I MHC antigen gradually increased in the corneal epithelium and stroma. Further immunohistochemical survey has revealed that L3T4 antigen bearing and Lyt 2 antigen bearing cells were induced to a similar extent with an equal rapidity in the local lymph nodes as well as in the corneal stroma. Transfer of these subpopulations to syngeneic nude mice showed that they played a role to prevent severe outcome of corneal herpetic infection. These results indicate that the corneal stroma is a major site of the host's immunological activities and both L3T4 and Lyt 2 bearing cells are equally important for the prevention of corneal herpetic infection.

Animals↗
PubMed1991

[Influenza A virus-induced mucociliary dysfunction of tubotympanum].

There is amount of epidemiologic, clinical and laboratory evidence to document that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated the direct influence of viruses on the tubotympanum. The purpose of this study is to establish the effect of influenza A virus invaded in the tubotympanum, in an attempt to elucidate the possible mechanism by which the virus contributes to the pathogenesis of OME. 80 guinea pigs with normal otoscopic findings were inoculated with 0.2ml suspension of influenza A (3.3 x 10(8)PFU/ml) into their tympanic cavities through their tympanic membranes. To serve as controls, the same number of guinea pigs were injected with 0.2ml of physiologic saline solution into their tympanic cavities. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions were observed only in the animals inoculated with the virus. Mucociliary dysfunction was observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the control. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the control. The mucociliary clearance time of the tubotympanum was more prolonged than that of the control at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphologic changes were observed in the tubotympanum treated with the virus. Major pathologies observed included a general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and new formed centrioles. However, the viral infection had an influence on the epithelial cells with new centrioles. Our study has demonstrated that viral infection could evoke mucociliary dysfunction of the tubotympanum and create an increased susceptibility to bacteria. Therefore, viral infection could enhance bacterial infectious process in the tubotympanum. Through the failure viruses could contribute to the occurrence of OME.

Animals↗
PubMed1991

YS-822A, a new polyene macrolide antibiotic. II. Planar structure of YS-822A.

The planar structure of a new polyene macrolide antibiotic, YS-822A, which was isolated from the culture filtrate of a mutant strain H-8 of Streptoverticillium eurocidicum var. asterocidicus S-822, was established as I on the basis of spectroscopic evidences and by comparison spectroscopic data with nystatin A1 (II) and amphotericin A (III), representative polyene macrolide antibiotics. Molecular formula of YS-822A was established as C37H59NO14 (MW 741) by elemental analysis, NMR, and FAB mass spectra. The UV spectrum of YS-822A was very similar to that of nystatin A1, suggesting that YS-822A also has a conjugated all-trans-tetraene moiety. 1H and 13C NMR spectra of YS-822A showed a number of broad and overlapped signals, but the 1H-1H and 13C-1H COSY spectra implied the existence of a mycosamine moiety and several other partial structures. The connectivity of these partial structures was established by extensive 2D NMR experiments, including homonuclear Hartmann-Hahn and heteronuclear multiple-bond connectivity measurements, which led to the determination of the gross planar structure of YS-822A as I.

Amphotericin B↗
PubMed1991

Purification and characterization of rice peroxidases.

Four peroxidase components, named RP-2, 4, 6, and 7, were isolated from rice (Oryza sativa L.) green leaves. Isoelectric focusing indicated that each preparation was homogeneous. The molecular weights of RP-2, 4, 6, and 7 estimated by SDS-PAGE were 48,000, 48,000, 40,000, and 39,500, and their isoelectric points were 5.4, 8.1, 9.3, and 9.2, respectively. The activity of every preparation was maximum around pH 5.0. Antisera against these purified enzymes were raised in rabbits. Ouchterlony double diffusion tests with these antisera suggested that RP-6 and 7 were immunochemically identical and RP-2 and 4 were identical in parts and that RP-6 and 7 were quite different from RP-2 and 4. Analysis of the N-terminal amino acid sequences also showed that these peroxidase components were classified into two groups. The polymerase chain reaction showed that RP-2 and/or RP-4 contained an active central region, which is homologous to other plant peroxidases.

Amino Acid Sequence↗
PubMed1991

[The effect of recombinant epidermal growth factor in corneal angiogenesis].

Recent advances in genetic engineering techniques have enabled large-scale manufacture of human epidermal growth factor (hEGF), making possible the clinical use of this particular agent in treating a variety of corneal epithelial disorders. In view of future application to humans, it has to be determined whether hEGF could induce neovascularization in the cornea upon topical instillation, since the angiogenic effect of mouse EGF on the cornea in vivo has been reported. For this, a sheet of slow-release form polymer (EVA) containing hEGF was surgically implanted into the rabbit corneal stroma in search for subsequent corneal neovascularization. EVA sheets contained one of the following agents: (1) 250ng hEGF, (2) 500ng hEGF, (3) 250ng bFGF (positive control), (4) vehicle alone (negative control). On 5 and 14 days after implantation, the corneas were excised, sectioned, and stained with hematoxylin and eosin for histological evaluation. Slit lamp examination revealed that marked neovascularization developed in the corneas when EVA sheets containing bFGF were implanted. A number of polymorphonuclear leukocytes were accumulated around the implants. However, neovascularization did not occur in the corneas when EVA sheets containing either concentrations of hEGF or vehicle alone were implanted. Only a few polymorphonuclear leukocytes infiltrated. This result indicates that as much as 500ng hEGF does not induce corneal neovascularization.

Animals↗
PubMed1991

Correlation between progression of diabetic retinopathy and blood glucose control.

The relationship between the progression of diabetic retinopathy and consecutive blood glucose control evaluated by glycosylated hemoglobin (HbA1) values was statistically analyzed based on 422 eyes of 211 diabetic subjects who were followed up 2 years or more. The Cox regression model (proportional hazard model) with HbA1, as a time-dependent covariate was applied in the analysis. The cumulative effect and the relative risk of HbA1 affecting the progression of diabetic retinopathy was estimated. The effect of the moving average of HbA1 values for the previous 1-30 months on the progression of retinopathy was assessed to investigate the cumulative effect of HbA1. The cumulative effect of HbA1 on the progression of diabetic retinopathy was significant when the time span of the moving average was 6 months or more than 6 months. The moving average of HbA1 value for 7 months was most relevant to the retinopathy progression. The relative risk corresponding to the increase in the moving average of HbA1 values for 6 months by 1, 2 or 3% was 1.18, 1.39 or 1.63, respectively. When the HbA1 level was adjusted to its average value in the subjects (9.6%), the estimated cumulative retinopathy progression rate for 6, 12, 18 or 24 month follow-up was 3.6, 14.5, 22.5 or 30.5%, respectively. The differences in the cumulative retinopathy progression rate between a well-controlled group with a low moving average of HbA1 value (3% lower than the average) and a poorly-controlled group with a high moving average of HbA1 value (3% higher than the average) were estimated as 3% (6-month follow-up) and 23% (24 months).

Adult↗