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Biomedical subjects

H Tanzawa

Publications and source records attributed to H Tanzawa.

At least 55 records · Page 3Linked to original sources
PubMed1994

The proto-oncogene C-raf-1 is highly expressed only in the hypertrophic zone of the growth plate.

Proto-oncogene c-raf-1, the cellular homologue of the acutely transforming oncogene v-raf, has a central role in the signal transduction pathways. The growth plate, due to its non-overlapping zones of chondrocyte maturation, provides a physiological in situ model for investigating the role of c-raf-1 in proliferation and differentiation of chondrocytes. In this study, Northern blotting was first performed to examine the expression of mRNA for c-raf-1 in the embryonic chick tibial growth plate. It revealed that the normal levels of c-raf-1 mRNA were associated with the whole growth plate. We then investigated the localization of c-raf-1 mRNA and c-raf-1 protein in the growth plate by in situ hybridization and immunohistochemistry in order to determine whether c-raf-1 is involved in chondrocyte maturation. Our results showed that c-raf-1 mRNA and c-raf-1 protein were detected only in the hypertrophic zone. The data suggest involvement of this proto-oncogene in chondrocyte differentiation and/or hypertrophy rather than in proliferation.

Animals↗
PubMed1991

Detection of human papillomavirus in head and neck tumors with DNA hybridization and immunohistochemical analysis.

The presence of human papillomavirus (HPV) DNA in oral, sinus, pharynx, and larynx lesions of Japanese patients was studied by Southern blot hybridization under less stringent (25% formamide, 42 degrees C) and stringent (50% formamide, 42 degrees C) conditions. Three samples from 10 benign tumors, and 3 of 30 malignant tumors, contained HPV DNA or HPV-related sequences. The HPV DNAs harbored in three laryngeal papillomas were HPV-11, -6, and -6 or -11, respectively. The HPV DNA and viral capsid antigens were easily detected by in situ hybridization, Western blotting, and peroxidase-antiperoxidase staining. However, neither the typical restriction pattern of HPV DNA nor viral antigen was identified in the malignant tumors, suggesting that subgenomic fragments remained integrated in the host cell DNA.

Antigens, Viral↗
PubMed1991

Statistical observation of osteosarcoma of the maxillofacial region in Japan. Analysis of 114 Japanese cases reported between 1930 and 1989.

In Japan 114 cases of osteosarcoma of the maxillofacial region have been reported during the past 60 years. The average age at the onset of the disease in this region was about one or two decades later than that of osteosarcoma of other regions. Females were affected more frequently (59.6%) than males (40.4%). The mandible was more frequently affected (58.8%) than the maxilla (41.2%). Swelling was the conspicuous symptom for osteosarcoma of the maxillofacial region. Most patients received surgical treatment with or without radiation and chemotherapy; however, the prognosis is poor, regardless of the type of treatment.

Adolescent↗
PubMed1991

Quantitative detection of spliced E6-E7 transcripts of human papillomavirus type 16 in cervical premalignant lesions.

The splicing patterns of E6-E7 transcripts of human papillomavirus type 16 (HPV16) in cervical premalignant lesions were quantitatively analyzed by S1 nuclease protection assay. The major E6-E7 transcripts in HPV16-containing cervical lesions (four cervical intraepithelial neoplasias and one invasive carcinoma) were from spliced E6*I/E7 mRNA. The unspliced E6/E7 mRNA, which can encode the full-length zinc finger protein E6, is expressed as 8 to 15% of E6-E7 transcripts. The spliced E6*II/E7 mRNAs were expressed as 14 to 24% of E6-E7 transcripts in most tissues. However, in HPV 16-containing cell lines, the expression levels of spliced and unspliced E6-E7 transcripts were variable.

Blotting, Southern↗
PubMed1990

Cell proliferation on hydrogels.

The adhesion and proliferation of mammalian fibroblasts (Flow 7000) on the surface of hydrophilic (copolymer of N-vinyl-2-pyrrolidone and methyl methacrylate) and hydrophobic [polymethylmethacrylate (PMMA) stereocomplex] hydrogels with a wide range in water content were studied morphologically and quantitatively. It was demonstrated that cell proliferation on hydrogels by a static culture method decreased as the water content of the gels increased. However, it is remarkable that the cell proliferation on PMMA hydrogels with a high water content is equivalent to that on glass Petri dishes. The results obtained in the proliferation of cells on the surface of these hydrogels closely correspond to the state of cell adhesion. When fresh medium or air was perfused from the opposite side of the PMMA hydrogel membrane on which the cells were proliferating (perfusion method), the cells continued to grow into a higher density than with the conventional static culture method. In the case of fresh medium perfusion, the amount of proliferated cell was dependent on both the permeability of the membrane and the density of the membrane "scaffolding." Virus multiplication in the cultured cells increased in proportion to the cell density, whereas the cell function was similar in both culture methods.

Cell Adhesion↗
PubMed1983

Analysis of deposits on high water content contact lenses.

Deposits on soft contact lenses of high water content were investigated morphologically and chemically and compared with those on conventional soft contact lenses of poly (2-hydroxyethyl methacrylate). The material of the lenses examined in this investigation was the crosslinked copolymer of methyl methacrylate and N-vinylpyrrolidone with a water content higher than 70%. Morphologically, the deposits on the lenses with high water content were found to have no characteristics distinguishable from those on conventional lenses. By the electron microscopic observation of the cross section of a lens that had become opaque, it was confirmed that the deposit was on the lens surface and that no deposit was within the lens. Some spots on the lenses were recognized as colonies of microorganisms, but the majority of the spots had no involvement by microorganisms. Surface analysis with Fourier transform infrared spectrometer (FT-IR) confirmed that the main component of the filmy deposit was protein. Protein was detected in most of the deposits. The amino acid compositions of the proteins were found to be close to that of lysozyme. From the elemental analysis of several spots, silicon, aluminum, iron, and some other elements were detected. The structural analysis of some spots by a laser Raman microprobe (MOLE) revealed the existence of lipids. In several cases, the deposits were found to have grown around a defect of the lens surface. A mechanism for the formation of deposits is suggested.

Amino Acids↗
PubMed1983

Ocular inserts for controlled release of antibiotics.

Ocular inserts impregnated with antibiotics (erythromycin and erythromycin estolate) which have sustained release characteristics were prepared, mainly for the purpose of trachoma therapy. In vitro experiments showed that the elution rate of a drug with low solubility in water (erythromycin estolate) is constant when the water content of the hydrogel insert is more than 30%. In the case of a drug with higher solubility (erythromycin), the elution rate depends on the water content. Some in vivo experiments using rabbit eyes were also reported.

Animals↗
PubMed1983

In vivo evaluation of ocular inserts of hydrogel impregnated with antibiotics for trachoma therapy.

Sustained release of antibiotics from hydrogel matrices in the eye was studied for the purpose of developing a new method for trachoma therapy. Copolymers of N-vinylpyrrolidone were moulded into an ocular insert and impregnated with erythromycin or erythromycin estolate. The antibiotic-hydrogel inserts completely suppressed the chlamydia trachomatis infection in the owl monkey eyes. The drug elution rates were a little lower in vivo than in vitro. By comparison of the drug elution rate in the human eye with that in the owl monkey eye, similar therapeutic effect is expected in the treatment of human trachoma.

Animals↗
PubMed1982

Permeability of heparinized hydrophilic polymer (H-RSD): application to semipermeable membrane for microencapsulation of activated charcoal.

A series of heparinized hydrophilic polymers (H-RSD) composed of a hydrophobic element, a nonionic hydrophilic element, a cationic element and ionically bound heparin was synthesized. The permeability of the H-RSD polymers with various chemical compositions and water contents was investigated. From the studies on the permeability, it has been found that in order to maintain good permeability after heparinization, the nonionic hydrophilic element is necessary. In addition, the microencapsulation of activated charcoal granules using a H-RSD polymer with a similar permeability to that of Cuprophan was examined. In vitro adsorption studies and in vivo direct hemoperfusion studies on the activated charcoal microencapsulated with the H-RSD polymer, show that the H-RSD coating prevents clot formation without loss of the absorption power of the activated charcoal.

Absorption↗
PubMed1982

The influence of heparinized polymers on the retention of platelets aggregability during storage.

The change in aggregability of the platelets stored in the storage tube fabricated from a newly developed heparinized hydrophilic polymer (H-RSD) has been studied in comparison with plasticized poly(vinyl chloride) (PVC) which is widely used for blood bags. Rabbit blood was directly withdrawn into the storage tube containing an anticoagulant from the carotid. Then the tube was mechanically sealed with screw cocks and centrifugated to prepare platelet-rich plasma (PRP) in the tube and again mechanically clamped to separate the PRP from the residual precipitate. The PRP was stored in situ in the storage tube at room temperature under agitation. During storage, the change in the aggregability of the PRP induced by adenosine diphosphate (ADP) was studied and the morphological change in the platelets adhered onto the inner surface of the storage tube was observed by scanning electron microscopy. In the H-RSD tube, the aggregability was maintained during two-day storage, while in the PVC tube, the aggregability was completely lost after one-day storage. The scanning electron microscopic studies demonstrated that the reduction in the aggregability of the stored platelets is closely correlated with the morphological deformation of the platelets adhered onto the surface of the storage tube.

Animals↗
PubMed1982

A new antithrombogenic material with long polyethyleneoxide chains.

The PVC-g-MnG polymers were synthesized by photo-induced graft copolymerization of methoxypoly (ethyleneoxide)monomethacrylate (MnG) with various chain lengths (n) of polyethyleneoxide (PEO) (n = 4, 9, 15, 23, 50, 100) as side chains to polyvinylchloride (PVC) with photo-sensitive dithiocarbamate groups. Antithrombogenicity has been evaluated in vitro and in vivo. The in vitro and in vivo results indicated that the adsorption of blood elements to the PVC-g-MnG significantly decreased with the increasing PEO chain length (n). From these findings it is suggested that the volume restriction effect resulted from the formation of long-chain PEO on the surface and which effectively suppresses the adsorption of blood elements and prevents the denaturation of blood elements.

Adsorption↗
PubMed1980

Mechanical properties of the soft contact lens of poly(methyl methacrylate-N-vinylpyrrolidone).

The mechanical properties of the hydrogel membrane of poly(methyl methacrylate-N-vinylpyrrolidone) were studied for the purpose of making soft contact lenses for extended wear. The dependence of tensile fracture energy, flexibility, and recovery from deformation on the water content and thickness of the hydrogel membrane was studied. Reducing the thickness of a lens was found to exert a more advantageous effect than increasing its water content on maximizing the tensile fracture energy under the condition of an adequate supply of oxygen to the cornea through the contact lens. As long as its water content is controlled between 63 and 78%, the contact lens made of poly(methyl methacrylate-N-vinylpyrrolidone) has the flexibility on the same order as that of conventional soft contact lenses of poly(2-hydroxyethyl methacrylate). The rate of recovery from deformation increases with water content, and the residual elongation is negligible in the range of water content over about 70%. It is concluded that practical requirements for use of these contact lenses, determined by these three mechanical properties, can be satisfied at the same time if the water content of the contact lens is adjusted at about 70%.

Contact Lenses, Hydrophilic↗
PubMed1977

A new antithrombogenic heparinized polymer.

A new antithrombogenic polymer was synthesized by photoinduced graft copolymerization of both a hydrophilic polymer and a cationic polymer to hydrophobic poly (vinyl chloride) copolymer, and by quarternizing and heparinizing the obtained graft copolymer. For polymers of various compositions obtained by the method described above, chemical composition, water absorption, membrane potential, and quantity of adsorbed heparin were determined and antithrombogenicity evaluated in vivo. Thus, it has been found that the polymer of excellent antithrombogenicity has a negative membrane potential, a moderate elution rate of heparin, adsorbs heparin in a quantity of approximately 15 wt-%, and has a degree of water adsorption of about 30 wt-%. Also, measurement of membrane potential was very useful for the estimation of the quantity of the adsorbed heparin and its change with time.

Absorption↗