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Biomedical subjects

Y Machida

Publications and source records attributed to Y Machida.

At least 91 records · Page 5Linked to original sources
PubMed1990

Effect of interpolymer complex formation on bioadhesive property and drug release phenomenon of compressed tablet consisting of chitosan and sodium hyaluronate.

The bioadhesion property of tablets consisting of chitosan (CS) and sodium hyaluronate (HA) was investigated using a lyophilized porcine dermis as a model of mucous membrane. Release phenomena of brilliant blue FCF (BBL) from the CS-HA tablets were also studied. BBL was employed as a model compound of water-soluble drugs. Strong adhesion forces were observed when the tablets were prepared from HA alone or a physical mixture of CS and HA. The adhesion of CS tablets was also obtained but it was rather weak. No effect of pH values in the media was observed on the adhesion force in these tablets. On the other hand, the release rate of BBL from CS-HA tablets was greatly affected by the change of the polymer mixing ratio, suggesting a possible interaction between CS and HA in the tablet following water penetration into the tablet.

Adhesiveness↗
PubMed1990

Intranasal administration of human fibroblast interferon in mice, rats, rabbits and dogs.

In previous studies on the nasal administration of human fibroblast interferon (HuIFN-beta), only rabbits have been used. Therefore, this route was investigated in mice, rats, rabbits and dogs. HuIFN-beta could be delivered across the nasal mucosa in mice, rats, rabbits and dogs, when it was mixed with sodium glycocholate as an absorption promoter. However, the pattern of the plasma HuIFN-beta concentration-time curve was different from that in rabbits. Rabbits gave the highest value of the maximum plasma HuIFN-beta concentration (Cmax), but plasma HuIFN-beta declined rapidly thereafter, upon nasal administration of the powder dosage form (8.45 x 10(2) IU/g). In rats and dogs, Cmax was lower than in rabbits, but plasma HuIFN-beta declined slowly after nasal administration of the powder or liquid dosage form (4-6 x 10(2) IU/g). These differences might be attributed to differences of absorption rate constant.

Administration, Intranasal↗
PubMed1990

Experimental study of pulpotomy with calcium hydroxide-iodoform paste in dogs' immature permanent teeth.

To investigate the healing process and continuous root development following pulpotomy with improved calcium hydroxide-iodoform paste, the authors performed an experimental study of pulpotomy in immature permanent teeth. Thirty five incompletely formed root canals in dogs were used, and radiographical and histopathological observations were made. The results lead to the conclusion that pulpotomy with improved calcium hydroxide-iodoform paste is a very effective treatment for immature permanent teeth.

Animals↗
PubMed1989

Regulation of IS1 transposition by the insA gene product.

The IS1 element contains two adjacent genes called insA and insB, both required for IS1 transposition and IS1-mediated plasmid cointegration. These two genes are transcribed polycistronically from the promoter in the left terminal inverted repeat of IS1 (insL). We constructed overexpression systems of these genes with the tac promoter, which are regulated by an exogenous inducer, isopropyl-beta-D-thiogalactopyranoside (IPTG). Then we have examined, under various conditions of induction with IPTG, how overexpression of these genes affects IS1 transposition, using an assay based on plasmid cointegration. When the insA and insB genes were organized identically to the wild-type IS1 genes and simultaneously expressed using low concentrations of IPTG, activity of a mutant IS1 in cis was restored, but not in trans. Higher IPTG concentrations resulted in lower transposition activity. Expression in trans of insA and insB results in a 50 to 100-fold reduction of the frequency of cointegration mediated by wild-type IS1. Such a reduction is also observed when only the insA gene is overexpressed in trans. Overexpression of either mutant insA or insB does not affect the cointegration event. Tests with the insA-lacZ fusion gene showed that the InsA product inhibits the expression of IS1 genes directed by its own promoter in insL. These results suggest that the InsA product regulates IS1 transposition by inhibiting expression of IS1 transposition genes in addition to acting as part of a transposase complex.

Bacterial Proteins↗
PubMed1989

Hepatic enzyme activities and plasma insulin concentrations in diabetic herbivorous voles.

The activities of the hepatic glycolytic enzymes glucokinase (GKase) and hexokinase (HKase) in herbivorous Microtus arvalis were very low and the hepatic fructose-1,6-diphosphatase (FDPase) activities were almost the same as those in C57BL/6J mice. Glycosuria was observed in over 50% of voles fed on a low fibre, high concentrate diet. Voles with a high incidence of glycosuria for over 6 weeks became insulin deficient. In these diabetic voles, the hepatic GKase, HKase and FDPase activities decreased considerably as a result of diminished insulin secretion and fatty degeneration of the hepatic cells. It was considered that M. arvalis would be a useful animal model in which to study disorders of glucose utilization in herbivora.

Animals↗
PubMed1989

Isolation of an auxin-regulated gene cDNA expressed during the transition from G0 to S phase in tobacco mesophyll protoplasts.

A cDNA clone for an auxin-regulated gene was isolated from a tobacco mesophyll protoplast cDNA library by differential screening. Nucleotide, sequence analysis showed that the deduced product of the gene, which we have designated par, is hydrophilic and is composed of 220 amino acids. No significant homology to other known proteins was detected. The mRNA of the par gene is approximately 900 bases long and its accumulation was detected in cultured mesophyll protoplasts as early as 30 min after the addition of 2,4-dichlorophenoxyacetic acid to the culture medium. The par mRNA was not detected in leaves or freshly prepared protoplasts or in protoplasts in the absence of 2,4-dichlorophenoxyacetic acid. Expression of the par gene was detected at a low level in actively dividing BY-2 tobacco suspension culture cells. The conspicuous accumulation of par mRNA before the initiation of DNA synthesis in tobacco mesophyll protoplasts suggests that the par gene product could play a role in the initiation of meristematic activity in differentiated mesophyll cells.

Amino Acid Sequence↗
PubMed1989

[An outbreak of enterocolitis due to Clostridium perfringens in a hospital for the severely disabled].

We had an outbreak of 14 cases of enterocolitis due to Clostridium perfringens (Cl. perfringens) in a hospital for the severe multiply-disabled, where the 100 disabled were admitted, in summer in 1985. The signs and symptoms shown by this enterocolitis were primarily diarrhea without fever and loss of appetite. The feces of 10 cases were examined bacteriologically. The test showed 10(3) to 10(6) cells of Cl. perfringens per one gram of their feces and all the strains isolated were untypable by the classification of Hobbs. Nine out of 10 cases were randomly selected and all of the 9 cases were proved to have enterotoxin producing strains. All the strains were highly sensitive to many kinds of antibiotics except kanamycin and gentamicin. Eleven out of the 14 cases were admitted in the same ward and the 7 out of the 11 cases were in the same room of this ward. Considering the spreading route of this infection, it is unlikely that this outbreak occurred due to food supplied from kitchen in this hospital, because all of the disabled, admitted in this hospital, had little chance by which some of the disabled only in a specific ward or room were supplied with bacteriologically contaminated meals from the point of view of cooking and supplying system of this hospital. Adding to this fact, if this outbreak was due to food-born infection, the symptoms of most patients should occur within 1-2 days, because the incubation period of this disease is within a day, however, the patients increased day by day for more than a week.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Factors affecting the bioadhesive property of tablets consisting of hydroxypropyl cellulose and carboxyvinyl polymer.

The bioadhesive property of tablets consisting of hydroxypropyl cellulose (HPC) and carboxyvinyl polymer (CP) was investigated using the mouse peritoneal membrane. The adhesion force was significantly affected by the mixing ratio of HPC and CP in the tablet, and the weakest adhesion force was observed at the ratio of 3:2 (HPC:CP). Interpolymer complex formation was confirmed between HPC and CP in the acidic medium by turbidity and viscosity measurements. The interaction between CP carboxyl groups and HPC molecules was considered to be a possible mechanism for this complex formation on the basis of a Fourier-transform infrared spectroscopy. These observations suggested that the adhesion force of the HPC--CP tablet to the mucous membrane was significantly affected by the interpolymer complex formation between HPC and CP.

Acrylic Resins↗
PubMed1989

Effect of absorption promoters in intranasal administration of human fibroblast interferon as a powder dosage form in rabbits.

The utility of the absorption promoters, sodium glycocholate (GC-Na), ethylenediamine dihydrochloride (EDTA-2Na), sodium caprylate (Cap-Na) and sodium salicylate (Sal-Na), in the intranasal administration of human fibroblast interferon-beta (HuIFN-beta) in rabbits was investigated. The optimal amount of added EDTA-2Na, Cap-Na and Sal-Na with respect to HuIFN-beta was examined for nasal absorption in the powder dosage form. Formulations of HuIFN-beta with GC-Na showed greatly enhanced intranasal HuIFN-beta absorption, as compared to the other absorption promoters. The results of a stability study on HuIFN-beta in homogenates of nasal mucosa suggested that GC-Na behaved as a hydrolysis inhibitor in the nasal mucosa and maintained the activity of HuIFN-beta.

Absorption↗
PubMed1989

Diabetic syndrome induced by monosodium aspartate administration in Microtus arvalis Pallas.

Administration of monosodium aspartate (MSA) to neonatal voles, Microtus arvalis Pallas induced neuronal necrosis in several brain regions including the arcuate and ventromedial hypothalamic nuclei. In the growing stage, 56.7% showed glycosuria. In the mild diabetic voles, blood glucose concentrations rose to 180 mg/dl (72 mg/dl in normal), and plasma insulin levels were also increased to 112 microU/ml (21 microU/ml in normal). In the severe diabetic voles, on the other hand, blood glucose concentrations rose over 250 mg/dl, and plasma insulin levels decreased under 10 microU/ml. Histopathological examination of the pancreatic islets revealed moderately enlarged islets, and nuclear hypertrophy and partial degranulation of B cells in the mild diabetic voles, and moderately to markedly enlarged islets, and marked degranulation, vacuolation and accumulation of glycogen granules of B cells in the severe diabetic voles. These results indicated that the diabetic syndrome in herbivorous voles was induced by administration of MSA and diabetic voles fell into marked insulin deficiency in the severe stage.

Animals↗
PubMed1989

[Clinical evaluation of 20K gold alloy inlay restorations on young permanent teeth from the viewpoint of tooth-emergence age].

UNLABELLED: We observed 173 cases of 20K gold alloy inlay restorations on young permanent premolars and molars and investigated the emergence age of all these teeth. The observation period of inlay restorations was from 1 year to 11 years and 6 months. Clinical evaluations were made by exploring with an explorer, roentgenography and color photography. RESULTS: 1. Changes in inlay restorations occurred in 1 case (0.6%) of discoloration and 4 cases (2.3%) of inlay dislodgement. 2. Changes in teeth occurred in 8 cases (4.6%) of secondary caries, 15 cases (8.7%) of new caries and 4 cases (2.3%) of pulpitis. 3. Clinical failures occurred in 32 cases, and 24 of those cases were restored within 2 years after tooth emergence. 4. Almost clinical failures occurred on the maxillary and mandibular first molars. 5. In 27 cases (15.6%), repeat restoration was necessary. In 10 of these cases, the original 20K gold alloy inlay restorations continued in use.

Child↗
PubMed1989

[Growth and development of the alveolar ridge after extraction of deciduous teeth and its clinical application].

This paper is a description of the growth and development of the alveolar ridge after extraction of deciduous teeth for the purpose of handling the appliance for denture guidance and its clinical application. The regions observed were regions of the maxillary and mandibular deciduous molars and maxillary deciduous incisors, frequently causing premature loss of deciduous teeth. Changes of the alveolar ridge width after extraction in all regions can be divided into the following three phases; decreasing, stable, increasing. The decreasing phase finished about four months after the extraction. The increasing phase began from about eight months prior to the emergence of the succedaneous teeth. The period of the stable phase differed according to the time of the extraction of the deciduous teeth, in other words, the earlier the deciduous teeth were extracted, the longer the stable phase was. The decrease of the alveolar ridge width in the regions of the maxillary incisor and maxillary molar were caused mainly by resorption of the labial or buccal alveolar ridge, although resorption of the palatal alveolar ridge scarcely occurred. On the other hand, the decrease of the alveolar ridge in the region of the mandibular deciduous molars was caused by resorption of both the buccal and lingual alveolar ridges. The alveolar ridge began to expand about eight months prior to the emergence of the succedaneous teeth. In regions of the maxillary deciduous molars and maxillary deciduous incisors, mainly the buccal or labial alveolar ridges began to expand. In the region of the mandibular deciduous molars, both the buccal and lingual alveolar ridges began to expand.+2

Alveolar Process↗
PubMed1989

Plasma levels following intranasal and intravenous administration of human interferon-beta to rabbits.

Rabbits were given single doses (2 x 10(6) IU) of human fibroblast interferon (HuIFN-beta) by the following routes of administration: (a) intravenous injection, (b) dropwise intranasal administration of a liquid dosage form, and (c) spraywise intranasal administration of a powder dosage form. Following the intravenous injection, plasma HuIFN-beta concentrations declined rapidly in a biphasic manner in agreement with a two-compartment model, whilst concentrations following the intranasal administrations conformed to a one-compartment model. Maximum plasma levels and the areas under the plasma concentration-time curve (AUC) in response to dose were studied in the case of the spray administration, and found to be proportional to dose. The systemic bioavailability of HuIFN-beta (administered with sodium glycocholate and excipients) via the nasal routes was about 3% of that via the intravenous route. The elimination half-lives did not differ significantly between these two routes of administration.

Administration, Intranasal↗
PubMed1989

Preparation and evaluation of intragastric buoyant preparations.

The design and preparation of two drug formulations which float in gastric juice are described. One, a buoyant tablet, consisted of powdered soybean protein, drug and sodium bicarbonate. The other, a laminated film-type preparation, consisted of a drug film, an effervescing film containing sodium bicarbonate and outer drug release regulating films. Cinnarizine, an acid-soluble drug, was chosen as model drug, and carboxyvinyl polymer, ethyl cellulose and hydroxypropyl cellulose were used in the preparation of the films. Both formulations showed favorable buoyancy in an in vitro acidic dissolution test medium and also sustained release properties. In an absorption study using beagle dogs, cinnarizine was found in the blood even 24 hr after oral administration of the buoyant tablet or film-type preparation. Similar buoyant tablets containing barium sulfate were administered orally to a healthy volunteer, and it was confirmed by roentgenography that the tablets floated for almost three hours.

Administration, Oral↗
PubMed1989

Buoyant sustained release granules based on chitosan.

Attempts to develop sustained release intragastric 'floating' granules based on chitosan are described, using chitosan of different degrees of deacetylation (chitosan H and L), in granular form or in laminated preparations. The granules were made from chitosan H (chitosan H granules), from a 1:1 mixture of chitosan H and L (1:1 mixture granules), from a 1:2 mixture of chitosan H and L (1:2 mixture granules), or from chitosan L (chitosan L granules). They were prepared by a method involving deacidification, had internal cavities, were immediately buoyant in both acidic and neutral fluids, and gave sustained release of prednisolone (used as a model drug). The laminated preparations, composed of a chitosan granule layer and a chitosan L membrane, were also immediately buoyant in the same fluids, and also provided sustained release of the model drug. The release properties were controlled by regulating the chitosan L content of the granules, or the chitosan L membrane thickness of the laminate. In an absorption study using beagle dogs, sustained drug absorption from these preparations was obtained.

Animals↗
PubMed1988

Right-hand border regions of octopine T-DNA are recognized by RNA polymerase of Agrobacterium as well as by VirD1 and VirD2 proteins.

The T-DNA of octopine Ti plasmid of Agrobacterium tumefaciens contains TL- and TR-DNA regions each bounded by 25 base-pair-repeats (designated A, B, C and D from left to right). Short DNA segments containing the borders B, C and D were found to function as promoter when placed in the rightward orientation upstream of promoter-less lacZ. Promoter consensus sequence of Agrobacterium were found within these border repeats and in their adjacent regions. The expression of lacZ was low when the segments contained the overdrive, a sequence known to enhance T-DNA transfer. Simultaneous overproduction of VirD1 and D2 proteins, endonuclease acting on the border repeats, interfered with the promoter functions of the border segments. In spite of their activity under these conditions, the border regions do not seem to be involved in the gene expression, because they are not followed by appropriate open reading frames. We propose that RNA polymerase of Agrobacterium competes with VirD products for T-DNA borders and thereby affects the transfer of T-DNA.

Arginine↗