Search PubMed⌕ Search

Biomedical subjects

K Miyajima

Publications and source records attributed to K Miyajima.

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

[Identification of urinary metabolites in a patient of acute poisoning by p-chloroaniline].

In order to clarify urinary metabolites of p-chloroaniline (p-CA), urine samples of a patient acutely poisoned with p-CA were analyzed by gas chromatography/mass spectrometry. Urinary metabolites were extracted with diethylether at pH 1.0 and pH 10 from urine samples hydrolyzed with acid and base and from intact urine samples. Aliquots of the ethereal extracts were injected into the gas chromatography, and p-CA and its metabolites were identified by comparing their mass spectra and retention times to those of standards. Six substances identified were as follows: p-CA, 2-amino-5-chlorophenol, 2,4-dichloroaniline, p-chloroformanilide and traces of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide. Since p-CA was mainly detected in the hydrolyzed urine samples, p-CA was considered to form conjugates in the urine. N-Acetylation reactions of p-CA were suggested to be weak in human, because extremely minute amounts of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide were detected in the urine.

Adult↗
PubMed1991

Mechanical stress as a stimulant to the production of osteocalcin in osteoblast-like cells.

When mechanical stress is applied, osteoblasts have shown to produce bone turnover stimulating hormones and enzymes like prostaglandin E2 (PGE2), cyclic AMP, alkaline phosphatase, and collagenase. Osteocalcin (bone Gla protein) is also a protein produced by osteoblasts to control bone metabolism. Thus, its production may also be stimulated by mechanical stress. The purpose of this investigation was to test if mechanical stress stimulates osteoblast-like cells to produce osteocalcin in vitro. The results suggest that osteocalcin production is stimulated at the initial stage of the culture by cyclic tension and relaxation force, and secretion may decrease with time.

Animals↗
PubMed1991

A human skeleton from the Ohguruwa remains.

In 1941, the Ohguruwa remains were discovered at the Mizuho sports ground site in Nagoya. They date from about 3000 B.C., which is the early Jomon era. When the stadium was reconstructed in 1980, four human skeletons were found. Three of them, however, were in poor condition and moreover, were incomplete. However, the second skeleton was in good condition and could almost be reconstructed, and this skeleton (No. 2) was used for our study. It was found in the classic posture with arms and legs folded. Some pieces of a dog's skeleton were also discovered near the No. 2 skeleton's chest. This particular skeleton generally showed characteristics typical of the Jomon era. It had a stout structure and was judged to be a middle aged male because of the following features. There was considerable attrition of the occlusal surfaces on the remaining teeth. The teeth were worn flat, probably owing to the hard food and to their use as a tool. Both canines and first premolars of the upper and lower arches had been extracted in accordance with the custom of the time. Typical caries and localized periodontal breakdown were not observed, although there was horizontal alveolar bone loss, especially in the anterior regions. The mastoid process was extremely large and prominent. The lateral prominence of the mandible was developed. Analysis of lateral cephalogram revealed that the mandible was in the anterior position. The angles of SNA, SNB and ANB were 89.6 degrees, 89.2 degrees and 0.4 degrees, respectively. The skeletal pattern was definitive Class III. The adaptive changes in the teeth, their supporting tissues, temporomandibular joints and the related muscles--the harmonious masticatory system--were all estimated.

Cephalometry↗
PubMed1991

The lactic acid and citric acid content in the gingival fluid of orthodontic patients.

Alveolar bone turnover has two phases: bone resorption and formation. Bone resorption entails both mineral removal and collagenolysis. A pH decrease over the local bone surface is required for mineral removal. Both lactic acid and citric acid has been suggested as the acids which remove crystals. During the orthodontic movement of teeth, a process of overall bone resorption occurs during displacement, whereas at the retention stage this process needs to be stopped in order to stabilize the alveolar bone. Thus, lactic acid and citric acid may be valid parameters of bone resorption intensity. The purpose of this investigation is firstly to test if these acids can be detected in gingival fluid around the moving teeth, and secondly to find if any changes occur before, during and after orthodontic tooth movement. The results indicate that these acids can be good parameters which show how favorably tooth movement is proceeding. They also show how stable the teeth are when orthodontic force is stopped to apply.

Adolescent↗
PubMed1991

[The use of the maxillary protractor in the treatment of cleft lip and palate: a report of two cases].

The patients who underwent reconstruction of cleft lip and palate had clinically abnormal characteristics such as cicatricial contracture in the cleft area, narrow arches, missing teeth, and fistula. Most of those patients showed severe class III malocclusion with underdevelopment of the maxillary complex. In such patients, the treatment objectives in orthodontics were mainly anterior and lateral expansions of the maxillary arches, and inhibition of mandibular growth. In recent years, the maxillary protractor has been used positively in the treatment of the underdeveloped maxillary complex. In this study, we report on two patients with cleft lip and palate, and underdevelopment of the maxillary complex. Maxillary protractors were used beneficially at the period of the dento-craniofacial growth spurt. In these two cases, improvement of disharmony was obtained in the antero-posterior relationship between the maxilla and the mandible. The effects of the treatment were forward movement of the maxilla and growth inhibition of the mandible. Accordingly, the use of the maxillary protractor for cleft lip and palate patients with underdeveloped maxilla at the period of the dento-craniofacial growth spurt was shown to be important.

Cleft Lip↗
PubMed1990

Phospholipid monolayers at the triolein-saline interface: production of microemulsion particles and conversion of monolayers to bilayers.

Interfacial tensions of phospholipid monolayer at the triolein (TO)-saline interface were measured. The adsorption isotherms and the interfacial pressure-molecular area curves were evaluated on the basis of the measurements. Phosphatidylcholine (PC) forms a highly condensed monolayer, with a large lateral attractive interaction; phosphatidylethanolamine (PE) and phosphatidylserine (PS) form expanded monolayers with smaller lateral interaction energies. At the lowest interfacial tension (the highest interfacial pressure), the mole fractions of PC, PE, and PS in the monolayers are estimated as 0.95, 0.73, and 0.88, respectively. Therefore, PC forms the most stable monolayer at the interface. These results are consistent with the finding that the stable TO particles in aqueous solution were produced by using PC as an emulsifier, and PE and PS did not stabilize the particles. The phase diagram of TO and PC mixtures in saline obtained from theoretical considerations predicts the equilibrium conversion of the monolayers on TO particles to bilayers. This process may be closely related to the transformations of very low density lipoproteins and chylomicrons to high-density lipoproteins in plasma. The particle sizes of the emulsion are calculated theoretically as a function of PC mole fraction in the TO-PC mixture and compared with the experimental values obtained from quasi-elastic light scattering (QLS) measurements.

Adsorption↗
PubMed1990

Effect of cyclodextrins on biological membrane. I. Effect of cyclodextrins on the absorption of a non-absorbable drug from rat small intestine and rectum.

The effects of three kinds of cyclodextrins (CyDs), alpha-, beta- and gamma-CyD on biological membranes were investigated by changes in absorption of a non-absorbable drug, sulfanilic acid (SA), from the rat small intestine and rectum using an in situ perfusion technique. The absorption of SA from the intestine was slight and was not affected by the addition of CyDs. After pretreatment with a mucolytic agent, N-acetyl-L-cysteine (N-Ac), the absorption of SA was increased compared with SA alone in the presence of only beta-CyD. Similar treatment with sodium deoxycholate (SDC) and sodium lauryl sulfate (SLS) to gastro-intestinal membrane showed the enhanced absorption of SA by the addition of beta-CyD. The mucin layer on the surface of the gastro-intestinal membrane may play an important role in the absorption of drugs. On the other hand, enhanced absorption of SA from the rat rectum was not induced by beta-CyD with or without pretreatment with N-Ac, SDC or SLS. Simultaneously, the release of neutral sugars in the perfusate after treatment with adjuvants was also observed with N-Ac, SDC and SLS. These results indicate that the mucin layer works as a barrier to the increased absorption of SA by beta-CyD.

Animals↗
PubMed1990

Interactions of lecithin and pig apolipoproteins of high density lipoproteins at the surface monolayer of reconstituted very small particles.

Cosonication of egg yolk lecithin and triolein with apolipoproteins isolated from pig high density lipoprotein (apoHDL) gave us reconstituted high density lipoprotein particles (r-HDLs) of 9 nm in average diameter. They were smaller than microemulsion particles (MEs) composed of the lipids (35 nm). The protein/egg yolk lecithin ratio in the fractionated r-HDLs was higher in the smaller particles. Binding of a hydrophobic probe, 2-p-toluidinylnaphthalene-6-sulfonate (TNS), to MEs, r-HDLs and apoHDL were evaluated on the basis of Halfman and Nishida's method. The reconstitution of apoHDL into MEs led to a 68% reduction in the binding of TNS and a small increase in the alpha-helix content as compared with free apoHDL. The binding experiments also showed the condensation of lecithin molecules at the r-HDL surface. The amphipathic helixes of apoHDL are located in the surface monolayer of egg yolk lecithin surrounding the triolein core. The intercalation of the hydrophobic residues of apoHDL between egg yolk lecithin molecules brings about a pronounced curvature of the surface and a decrease in the particle diameter.

Animals↗
PubMed1990

Beneficial effect of nipradilol (K-351) on acute myocardial ischemia. Study of the relationship between regional myocardial blood flow and energy metabolism.

To examine the effects of nipradilol on ischemic myocardium, experiments were performed on regional myocardial blood flow (MBF) and energy metabolism in anesthetized, open-chest dogs. Nipradilol at a dose of 0.3 mg/kg was i.v.-administered 10 min after coronary ligation. MBFs at various sites, including ischemic and non-ischemic areas, were determined by the hydrogen gas clearance method. The levels of ATP and creatine phosphate (CP) at the site of MBF determination were measured 60 min after ligation, and mitochondrial function (RCI, QO2) in the ischemic and non-ischemic areas was determined. Following nipradilol administration, aortic pressure and heart rate were significantly lowered. In ischemic areas with MBF below 40 ml/min/100 g, nipradilol had no influence on MBF. However, the tissue level of ATP in nipradilol treated hearts was significantly higher as compared with untreated hearts. In the area of mild ischemia with MBF of 40-60 ml/min/100 g, nipradilol preserved the tissue ATP and CP levels in spite of a decrease in MBF. Moreover, an inhibition of the decrease in mitochondrial respiratory function was observed in ischemic areas with MBF below 20 ml/min/100 g. Thus, nipradilol administered following ischemia preserved ATP content and mitochondrial function in the ischemic myocardium with reduction of heart rate and aortic pressure. This suggests that nipradilol exerts a cardioprotective effect in acute ischemia. It seems that the cardioprotective effect is due to a decrease in myocardial oxygen demand and preservation of mitochondrial function.

Adenosine Triphosphate↗
PubMed1990

[Effect of PTH and periodic tension on osteoblast-like cells for collagenase synthesis].

The purpose of the present study was to determine whether cyclically applied tension stimulates osteoblast-like cells to produce collagenase as well as parathyroid hormone (PTH) does. Experimental evidences suggest that osteoblast growth can be altered by various extrinsic control factors, including continuous and intermittent mechanical forces. In the present study, morphological change and collagenase synthesis were observed for both cultures that were added PTH and under the periodic tension condition applied on osteoblast-like cells and their parallel controls. periodic tension was used because it was thought to more closely mimic the in vivo functional situation. An initial seeding density of 50,000 cells/well was used for both the PTH stimulated and mechanically stimulated cells and their controls. For the mechanically stimulated cultures, the cells were subjected to the following tension/relaxation combination; 3 cycles/minute at 17% elongation of tensional force. The cells were fixed at 24, 72, and 120 hours after the start of experiments and collagenase was stained immunohistochemically. The following results were obtained: 1. PTH stimulated collagenase production from the first through the fifth day; 2. Periodic tension changed cell morphology from round to stellate; and 3. Periodic tension increased collagenase production from the first through the fifth day.

Animals↗
PubMed1990

Effects of complete separation of condyle on the facial growth of growing rats.

Normal mastication needs condylar support. Mandibular condyle is thought to be one of the factors which control facial growth. To determine which parts of the face are affected by unilateral complete condylotomy including surrounding connected soft tissues, thirty-nine male Wistar rats, 5 weeks of age, were divided into control, sham treated and experimental groups. The control animals received no treatment, where as the left mandibular condyles of the experimental animals were condylotomized. Soft X-rays of the animals of both groups were taken every two weeks, and all were killed six weeks after treatment. Roentgenografically, it was observed in the experimental animals that a functional condyle-like process generated to fill the condylar space of glenoid fossa. This process was smaller than normal condyle of the control anomals. Furthermore, ANOVA revealed significant differences (P less than 0.01) in some facial structures including facial height as well as mandibular length, which were still affected at six weeks after the surgery. The result of the present investigation suggests that unilateral condylotomy induced the production of a functional condyle-like process and caused some facial deformities.

Analysis of Variance↗
PubMed1990

Some considerations about maintenance of the mandibular position for adult patient with TMJ disorder.

The patient was twenty-three year old female with TMJ disorder and crowding. She had often had a clicking sound caused probably by malocclusion since she was eighteen years of age. Limitation of mouth opening with TMJ locking has been occurring since she had an impacted right lower third molar extracted at nineteen. A stabilization splint was applied for better mandibular position to rectify the TMJ disorder. The clinical symptom was relieved one month later, so the malocclusion was treated with a multi-bracket appliance. Since cross bite in [formula: see text] was corrected in a year and three months, symptoms of the TMJ disorder disappeared and this condition has remained stable for the past year. A stabilization retainer worn at night was considered necessary to prevent a relapse of the dentition and mandibular position, and to keep the masticatory muscles relaxed. For the purpose of stabilizing the TMJ condition and occlusion, the patient was taught unilateral mastication in order to diminish the difference between sides in chewing force, because only one side had been habitually used for a long time. It is suggested that such an alternative chewing habit will improve functional stability following the structural correction.

Adult↗
PubMed1990

[Effects of periodic tension on osteoblast-like cells for cell differentiation and alkaline phosphatase activity].

Bone remodeling requires bone resorption and formation. Bone formation involves osteoblastic activity. Both intermittent and continuous mechanical forces have been proved to affect osteoblast differentiation in vivo. It is evident in the present investigation that periodically applied tension alter cell division, protein synthesis and alkaline phosphatase activity. An initial seeding density of 50,000 cells/well was used for both the mechanically stimulated cells and controls. For the experimental cultures, the cells were subjected to different levels of tension applied at different frequencies; 1. Low frequency (0.3 cycles/minute) at moderate tension (17% elongation); 2. Moderate frequency (3 cycles/minute) at moderate tension (17% elongation); 3. High frequency (30 cycles/minute) at moderate tension (17% elongation); 4. Low tension (9% elongation at moderate frequency (3 cycles/minute); 5. High tension (22% elongation) at moderate frequency (3 cycles/minute). Cell numbers, protein synthesis and alkaline phosphatase activity were measured for each treatment combination, as well as for the unstressed controls. The cells were harvested at 24, 72, and 120 hours after the start of force application. Analysis of variance revealed that periodically applied tension stimulated cell activity in cultured UMR 106-01 cells: 1. Seventeen percent elongation at 3 and 30 cycles/minute was the optimum condition for stimulating osteoblastic cell division; and 2. High frequency stimulation at moderate tension and high tension at moderate frequency stimulated alkaline phosphatase activity. Given these findings, the following conclusions seem warranted: 1. There may be an optimal magnitude of tensional force that stimulates osteoblast activity. Beyond this optimal level, osteoblasts may lose potential to have cell divisions; 2. The optimal condition of tension might be different for cell division and other cell functions. Although high tension (22% elongation) did not stimulate cell division, alkaline phosphatase activity showed significantly high measurement at this condition; and 3. in the light of both the present study and previous investigations, periodically applied tension may stimulate both collagenase (a parameter of bone resorption) and alkaline phosphatase (a parameter of bone formation) production.

Alkaline Phosphatase↗
PubMed1990

[Treated case with horizontally impacted mandibular first molar caused by submerged primary molar].

A case is here presented in which mandibular first molar was horizontally impacted under the submerged primary molar. The patient was an 8 year-old-boy referred from a general dentist through the Department of Pedodontics in this hospital, whose chief complaint was a horizontally impacted mandibular first molar. Skeletally, diagnosis revealed an Angle Class II Division 2 malocclusion. The impacted first molar was uprighted with a lingual arch and a utility arch following the extraction of the submerged primary molar. The submerged primary molar was probably ankylosed causing a locking of the first molar which rotated as the root formed. The result of rotation during forming twisted the roots of the first molar, which will make root canal treatment difficult if the pulp is infected in the future. It may concluded that dental arches should be carefully observed even in the deciduous dentition.

Ankylosis↗
PubMed1990

[Root resorption of mandibular second molars by impacted third molars. A case report with some reviews].

A case is presented here in which mandibular third molars resorbed second molars bilaterally 4 years 9 months after orthodontic treatment was finished. The initial problem was open bite, which was treated by non-extraction followed by a period for observing the third molars. During that period, the mandibular third molars moved mesially to resorb the roots of the second molars. The injured second molars were, therefore, extracted and the third molars were uprighted. During adolescence, third molars are erupting. When the posterior space is not enough for the third molars, they often erupt buccally or lingually, or impact distally toward the second molars and cause root resorption. It is suggested that the third molars should be observed carefully till they erupt or are extracted.

Adolescent↗
PubMed1990

[Orthodontic treatment of malocclusion with periodontitis].

Adults with untreated malocclusions suffer from more periodontal disease than if their malocclusion had been corrected orthodontically. What orthodontists can offer in the management of patients with periodontal disease, how they can help the periodontists and the patients, and how the periodontists can help the orthodontist make treatment safe and purposefully are widely discussed. The purpose of this study is, therefore, to discuss how orthodontic patients with severe periodontitis could be treated and what we should do for these patients during the treatment as well as at their initial visit. One case is presented as an example of treatment for malocclusion with sever periodontitis: The patient was a 23 years 8 months female with a chief complaint of protrusion of upper incisors. Since clinical examination revealed severe periodontitis, periodontal treatment was undertaken for one year prior to orthodontic treatment. From these observations, we are conviced of the importance again of the global approach and the team treatment method in treating malocclusions with periodontitis.

Adult↗
PubMed1989

Hypelcin A, an alpha-aminoisobutyric acid containing antibiotic peptide, induced permeability change of phosphatidylcholine bilayers.

Interactions of hypelcin A, an alpha-aminoisobutyric acid containing antibiotic peptide, with phosphatidylcholine vesicles were investigated to obtain information on its bioactive mechanism. The peptide induced the leakage of a fluorescent dye, calcein, entrapped in sonicated vesicles. The leakage rate depended on both the peptide and the lipid concentrations. Analysis of this dependency indicated that the leakage was due to the monomeric peptide and that the membrane-perturbing activity of the monomer was higher for solid distearoylphosphatidylcholine vesicles than for fluid egg yolk phosphatidylcholine vesicles. Hypelcin A also affected the gel to liquid-crystalline phase transition of dipalmitoylphosphatidylcholine multilamellar vesicles. The transition was broadened with a reduced transition enthalpy, suggesting the peptide strongly binds the surrounding lipids to perturb the bilayer lipid packing. A circular dichroism study revealed that the helical content of hypelcin A increases upon membrane binding. We concluded that the monomeric peptide with an increased helical content, complexed with the lipids, perturbs the lipid organization and induces the increased permeability.

Alamethicin↗