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Biomedical subjects

M Nakata

Publications and source records attributed to M Nakata.

At least 253 records · Page 14Linked to original sources
PubMed1990

Effects of D-baclofen and L-baclofen on the trigeminal nucleus.

D-Baclofen reduced the response to L-baclofen in the feline trigeminal nucleus, the spinal cord of the rat and in patients with trigeminal neuralgia, but not in slices of hippocampus or neocortex. The iontophoretic application of 10-20 nA L-baclofen depressed excitatory transmission in the trigeminal nucleus oralis, similar to the effect of 0.1-0.4 mg/kg L-baclofen, given intravenously. The concomitant iontophoresis of 10-20 nA D-baclofen reduced the effect of iontophoretically applied L-baclofen. However, larger doses of D-baclofen (30-60 nA) did not, while still larger doses (200-400 nA) by themselves depressed response of the neuron, similar to the action of small doses of L-baclofen. The iontophoresis of 30-40 nA L-baclofen had a stronger effect than that previously obtained with systemic administration and D-baclofen was not able to block it. These observations suggest that D-baclofen is a partial agonist at the GABAB receptor. Failure to observe a blocking effect of D-baclofen in slices of hippocampus or neocortex could be due to the larger doses used or to a difference in receptor types. The observations emphasise the need to test drugs at therapeutic concentrations in an appropriate model, in order to predict reliably their therapeutic actions.

Animals↗
PubMed1990

Five-year follow-up caries study among Nigerian children.

Eighty-five children (age in 1981, 3-9 yr) examined in the 1981 survey in Ile-Ife, Nigeria, were seen again in 1986. In addition cross-sectional caries data in a small sample of 6-14-yr-olds were compared with data obtained in 1986. Results show that caries prevalence rate and the average number of DMFT increased slightly in the urban area, but was still very low. Both caries prevalence and the average number of DMFT decreased in rural areas because attrition proceeded faster than did caries.

Adolescent↗
PubMed1990

Genetic study of dentinal growth in mandibular first molars of mice.

The dentinal growth of mandibular molars of mice could be determined by genetic and environmental factors as are other quantitative characters, such as crown size and craniofacial size. To study the relative contribution of genetic and environmental factors to dentinal growth, a partial diallel cross was carried out by the mating of one pair from each of six strains of mice. In each F1 offspring, the total amount of dentinal formation in the first molar of the right mandible was quantified as a volume by the time-marking method, using nitrilotri-acetate lead with the computerized image scanning system, and then analyzed by a quantitative genetic method. The result obtained was as follows: In either sex, both additive genetic and nonadditive genetic variance components of the accumulative volume of dentinal formation in the first molar were relatively large throughout the experimental period, while the environmental variance component was much smaller. Thus it could be concluded that the genetic factor contributed more to the whole process of dentinal growth in the first molar rather than the environmental one in this F1 population.

Analysis of Variance↗
PubMed1990

[Three-dimensional change of the occlusal facets in primary dentition before and after the eruption of first permanent molars].

A system to measure the three-dimensional architecture of the occlusal surface was developed to clarify the three-dimensional change of the morphology of occlusal facets that was considered as the trace mark of the chewing function. The three-dimensional measuring and analyzing system of the occlusal surface was composed of two components, the measuring system to obtain the three-dimensional coordinates on the surface contour of the tooth crown and the analyzing system to calculate the minute morphology in the three dimensions. The reproducibility of this system was evaluated with use of the standard block of stainless steel designed for this purpose and was shown to be very accurate. By application of this system, the three-dimensional changes of the occlusal facets on primary canines and primary second molars were investigated on the serial primary dental casts taken before and after the eruption of the first permanent molars from eleven children (seven boys and four girls). The results were as follows: On the primary second molars of the maxilla and mandible, before the eruption of the first permanent molars, the occlusal facets were distributed mainly on the functional cusps. The occlusal facets were found also on the non-functional cusps after the eruption of first permanent molars. As a consequence, the increase in the number of occlusal facets from before to after the eruption of first permanent molars was statistically significant for both maxillary and mandibular primary second molars. In regard to the morphological change in three dimensions, the occlusal facets that were facing mesially or distally before the eruption of first permanent molars changed its direction buccally or lingually and became almost parallel to the datum plane of the mandibular dental arch after the eruption of the first permanent molars. It was also found that the occlusal facets of both jaws in the occlusal relationship were almost parallel to each other. In addition, the amounts of angular change before and after the eruption of first permanent molars were significantly correlated between the maxillary and mandibular occlusal facets. It can be concluded that the coordinating change of the occlusal facets in three dimensions may exist between both jaws during the development of chewing function.

Child↗
PubMed1990

[Effect of maxillary protracting bow appliance on reversed occlusion in deciduous dentition].

Previously we investigated the frequency of malocclusion in children who visited the Pedodontic Clinic of Kyushu University and the types of appliances to treat the reversed occlusion in deciduous dentition. The purpose of this study was to evaluate the effects of the maxillary protracting bow appliance to the reversed occlusion in deciduous dentition. Patients at the Hellman's dental age IIA and without molar cross-bite were selected. Eleven patients (6 males and 5 females) were treated with the maxillary protracting bow appliance, and 9 patients (5 males and 4 females) were treated with the chin cap. The controls were 15 patients (5 males and 10 females) without, distal step type of terminal plane, caries and malocclusion. For the sake of evaluation, the study models and lateral cephalograms were analyzed, which were taken before and after the correction of reversed occlusion. The results were as follows: 1. The effects of maxillary protracting bow appliance were the maxillary forward movement associated with counter-clockwise rotation of the nasal floor and the mandibular backward movement associated with clockwise rotation. 2. The maxillary protracting caused the labial inclination of the primary incisors in the maxilla, but the dental arch length was reduced by the mesial movement of the primary second molars in the maxilla. 3. From the results of multiple regression analysis in the maxillary protracting group, it was indicated that the increase of the overjet was attributable to the change of angles of SN-GN, SNB, SNA and GZN.

Cephalometry↗
PubMed1990

[Long-term splinting of a traumatic upper permanent incisor with root fracture: report of a case].

Splinting was administered in a case of a traumatic upper right permanent incisor with root fracture. The patient was a boy, 11 years and 10 months old. The radiographical examination indicated that the injured tooth, that had already completed the apical growth, fractured horizontally at the middle 1/3 part of root. Clinical findings showed severe mobility of the coronal fragment of the injured tooth and a small amount of bleeding from the gingival sulcus, but there was almost no disposition of the coronal fragment and it was found to be vital in the electric pulp test. Immobilizing the coronal fragment of the injured tooth with the resin splint bonded directly to the tooth surfaces was prescribed. After 31 months, the pulp of the injured tooth remained vital, and after the elimination of the line of fracture and no symptoms of ankylosis were radiographically confirmed, the splint was then removed. From the case reported above the following implications were obtained: Although the previous investigators reported that the term of splinting teeth with root fractures was for 2-3 months, and prognosis of the injured teeth with root fractures having severe mobility of the coronal segments might be unfavorable, it was also indicated that the healing process by calcification might be possible with the use of long term splinting, as the pulp remained vital. In this case, it was found that the repair by calcification appeared initially on the proximate portion of the pulp at the fractured line, and slowly proceeded into the direction of the site of the outer surface of the root along the fractured line.

Child↗
PubMed1990

[An in vitro study of wear and marginal fracture of posterior composite resins].

The collision-and-abrasion test was performed to reproduce the change of the surface structures of posterior composite resins by the stress of mastication and occlusion. Also the effect of the stress on wear and marginal fracture of composites was estimated qualitatively and quantitatively between the cavities with round bevel, straight bevel and butt joint. Extracted human posterior teeth were used as materials, and round or straight bevels were prepared along the margin of the standardized cavities using the bevel-preparing burs which had been designed by us. Light cured posterior composite resin (Occlusin/ICI Co.) was used as the restoration material. Also the surface structures were examined before and after the collision-and-abrasion test with the scanning electron microscope and laser measuring device for the surface morphology. The following results were obtained. 1. The collision-and-abrasion test with use of the slurry of polymethyl methacrylate (PMMA) powder as abrasive showed better reproducing ability of the in vivo change of the posterior composite restorations. 2. The collision stress was found to be one of the main causes for the wear and marginal fracture of composites. 3. It was found that the measurement for wear and marginal fracture of restorations could be performed three-dimensionally with high precision and in shorter time by using a laser device. 4. Marginal fracture resistance of composite resins is influenced by the adhesion with tooth structure and the marginal thickness. Therefore, the best marginal shape for posterior composite restoration is the round bevel.

Composite Resins↗
PubMed1990

[Cerebrospinal fluid transfer of cefbuperazone in the blood-brain barrier lesions of neurosurgical patients].

Cefbuperazone (CBPZ) was given in 15 patients after surgery. There was no infections except for 1 case in which signs of infections were suspected. As side effects, slight elevations in hepatic transaminase levels were observed in 3 patients during the CBPZ chemotherapy. CBPZ concentrations in 7 patients were studied. The subjects were divided into 3 groups according to CT finding during the chemotherapy to correlate CBPZ concentrations to degrees of blood-brain barrier lesions; Group I: no enhancement, Group II: mild or focal enhancement, Group III: diffuse and marked enhancement. It was interesting to note that the more marked enhancement were obtained, the higher levels of CSF concentration of CBPZ.

Adolescent↗
PubMed1990

Genetic study on the mandibular molar size of rats.

Tooth size is determined by genetic and environmental factors like other quantitative characters such as body weight and body height. However, the degree of the relative contribution of both factors to the determination of tooth size has not been well clarified. In order to study the genetic and environmental factors affecting tooth size, we carried out a diallel cross mating by the cohabitation of pairs of males and females among 10 strains of rats. The bucco-lingual widths of the first, second, and third molars of the right mandible were measured in each offspring of F1 population. The body weight was also measured as a parameter that might indicate systemic growth factor in connection with tooth development. The quantitative genetic analysis was performed based on Wearden's model (Heredity 19:669-680, 1964). As a result, the size of the first and the second molars was more significantly controlled by genetic effect than maternal effect, while maternal effect could not be ignored for the size of the third molar in addition to genetic effect. The genetic effect on body weight became greater with age, while the maternal effect showed its maximum influence upon the body weight around the weaning. It is concluded that the size of the molar teeth beginning to develop in the uterus and to be calcified just after birth was mainly controlled by genetic factor, and that the size of the molar teeth beginning to develop approximately after birth was mainly controlled by maternal effect affecting body weight at the same period.

Animals↗
PubMed1989

Activation of peripheral blood T cells via the p75 interleukin 2 receptor.

By using mAb and flow cytometry, a constitutive expression of the p75 IL-2R was revealed in human peripheral blood CD8+ T cells and TCR delta-1+ T cells as well as in CD16+ NK cells. Anti-p75 IL-2R mAb almost completely inhibited the induction of cytolytic activity in these T cells by brief exposure to IL-2, as estimated by anti-TCR/CD3 mAb-targeted cytotoxicity. While anti-p55 IL-2R mAb alone inhibited the response only modestly, maximal inhibition was achieved by combining both anti-p55 and anti-p75 IL-2R mAbs. These results indicate that the p75 IL-2R constitutively expressed on peripheral blood CD8+ T cells and TCR delta-1+ T cells is predominantly responsible for the direct activation of these cells by IL-2.

Antibodies, Monoclonal↗
PubMed1989

Antigen common to several species, recognized by a rat monoclonal antibody raised against syngeneic rat bladder tumor.

A rat monoclonal antibody (MAb) termed RS-II (Ig M) was obtained by syngeneic immunization with rat bladder tumor cells induced by N-butyl, N-hydroxybutylnitrosamine (BBN). Immunocytochemical analysis showed that RS-II is also reactive with mouse, dog and human bladder tumor-cell lines and some other human tumor-cell lines but not myeloma or leukemia cells. Immunohistochemical examination of paraffin-embedded tissues has shown that RS-II is reactive with mouse, rat, dog and human bladder tumors (5/5, 5/5, 1/1, 31/49) and some other tumors, but not with normal human urothelium or normal rat tissues. The antigen is expressed on the majority of low-grade or well-differentiated tumors, but less on advanced, invasive tumors. The immunofluorescence staining pattern of cultured cells was cytoplasmic and filamentous. Immunoblotting revealed that the antigen is a Mr 54,000 to Mr 56,000 protein which was extracted with difficulty from the cultured cells with Triton X-100. The antigen was also detected in the culture supernatant by means of ELISA. Our results suggest that the epitope is expressed on cytoskeletons common to a wide variety of mammalian cells at a certain stage of differentiation.

Animals↗
PubMed1989

[A study of image processing condition of mammography using FCR (Fuji Computed Radiography)].

Image processing conditions of mammography using FCR (Fuji Computed Radiography) to detect mass shadow, marginal finding and microcalcification of breast cancer were examined. The subjects of the examination for mass shadow and marginal finding were 25 cases out of 55 breast cancers operated from December 1986 to August 1988. Three surgeons and two radiologists evaluated processing conditions. The optimum conditions of spatial frequency enhancement were RN(1 or 3) RT(P) RE(1.0) for mass shadow and RN(7) RT(P) RE(2.0) for marginal finding under routine gradational enhancement condition. ROC curves obtained from the phantom with a granule of aluminum were used to optimize image processing condition for microcalcification. It was shown that GT(M)GA(1.0)GC(0.6)RN(9)RT(F)RE(4.0) gave the best detectability among five image processing conditions.

Adult↗
PubMed1989

An enzyme immunoassay for human lymphotoxin.

A highly sensitive and specific enzyme immunoassay (EIA) for human lymphotoxin (hLT) has been developed. The assay is based upon a sandwich system employing two kinds of anti-hLT antibodies with neutralizing activity. One of them was mouse monoclonal antibody raised against Escherichia coli-derived recombinant hLT with a deletion of 20 amino-terminal amino acids and used as labelled antibody. The other was rabbit antibody raised against the carboxyl-terminal portion of hLT and used as solid-phase antibody. The EIA employing such a combination was able to detect less than 50 pg/ml of hLT, showing that this method was approximately 5-10 times higher sensitivity than the conventional bioassay employing L929 cell-lysis. The mean recovery of hLT added to serum specimens was 101% and the coefficients of variation were 3.3-7.8% (intra-assay) and 2.9-17.2% (interassay). There was a good correlation between the present EIA and the bioassay (r = 0.93).

Animals↗
PubMed1989

[Effects of nizatidine, a new histamine H2-receptor antagonist, on gastric acid secretion and various gastric and duodenal lesions in rats: comparison with cimetidine].

We examined the antisecretory and antilesion activities of nizatidine in rats. Male SD or Donryu rats (200-260 g) were used under fasted or fed conditions. Nizatidine, given orally or parenterally (intraperitoneally, subcutaneously or intraduodenally) at 0.3-150 mg/kg, inhibited both basal (pylorus-ligation preparations) and histamine-stimulated gastric acid secretion (acute fistula preparations) in a dose-dependent manner. The potency of nizatidine was 2 to 8 times greater than cimetidine when the ED50 values (mg/kg or mu mole/kg) of each agent were compared. The antisecretory activity of nizatidine, given orally, persisted for more than 3.5 hr, but disappeared 6 hr later. Nizatidine, given orally or subcutaneously at 0.3-150 mg/kg, prevented development of gastric lesions induced by water immersion, pylorus ligation (Shay), histamine, aspirin, or indomethacin in a dose-dependent manner. Duodenal ulcers induced by mepirizole were also markedly prevented with nizatidine. The potency of nizatidine on stress lesions or duodenal ulcers was about 20 or 14 times greater than that of cimetidine, respectively. Nizatidine, given orally 3 times a day for 4 weeks, significantly (P less than 0.05) accelerated the healing of acetic acid-induced gastric ulcers which were delayed by prolonged treatment with indomethacin. These results suggest that nizatidine is a useful drug for the treatment of peptic ulcers in man.

Animals↗
PubMed1989

Inhibitory effect of antibiotic cerulenin on the respiratory burst in phagocytes. I. Effects of cerulenin on active oxygen-generation and lipid metabolism in phagocytes.

The antibiotic cerulenin, a known inhibitor of fatty acid and sterol synthesis, inhibited bactericidal activity of mouse peritoneal macrophages and chemiluminescence (CL) response upon phagocytosis. The antibiotic also inhibited the CL response of human neutrophils upon exposure to various stimuli such as chemotactic peptide N-formylmethionylleucylphenylalanine (fMLP), calcium ionophore A23187 and Staphylococcal delta toxin. The loss of CL response of both types of cells was observed only after incubation of the cells with cerulenin for certain periods. The results of radioactive precursor incorporation suggest that lipid metabolism blocked by cerulenin affected in turn signal transduction across the cell membrane and inhibited CL production in these cells.

Animals↗
PubMed1989

Inhibitory effect of antibiotic cerulenin on the respiratory burst in phagocytes. II. Inhibition by cerulenin of intracellular calcium mobilization in human neutrophils.

Generation of superoxide anion (O2-) and mobilization of intracellular Ca2+ in human neutrophils upon exposure to stimuli such as N-formylmethionylleucylphenylalanine (fMLP) were inhibited by the antibiotic cerulenin, which inhibits fatty acid and cholesterol biosynthesis. The inhibition of O2- generation and Ca2+-mobilization required certain periods of incubation with cerulenin and both abilities of the cells were gradually lost following a similar time-course. In contrast, significant Ca2+-influx from the medium was observed in cerulenin-treated cells as well as untreated cells. The results suggest that an event which coincides with the Ca2+-mobilization and not Ca2+ per se is important for the induction of O2- generation in the fMLP-stimulated cells and that this step is blocked in cerulenin-treated cells. Phorbol myristate acetate or synthetic 1-oleoyl-2-acetylglycerol were able to bypass the block and induced O2- generation in cerulenin-treated cells.

Antifungal Agents↗
PubMed1989

[Investigation into the actual condition of patients with occlusal disharmony at the Pedodontic Clinic of Kyushu University. Cases of anterior cross-bite in the deciduous dentition].

The total number of subjects was 2754 children (1354 boys and 1402 girls), who visited the Pedodontic Clinic of Kyushu University during the 5 year period from April 1st 1981 to March 31st 1986. We investigated the actual conditions of patients who complained of occlusal disharmony and who were ascertained to be associated with occlusal disharmony. The results were as follows: 1. The percentage ratio of patients with chief complaints concerning occlusions was 14.5% and the percentage of patients with various type of complaints as well as the problem of occlusion was 8.1%. The ratio of the sex of the patients who complained of their occlusal disharmony was 43.0% for boys and 57.0% for girls. 2. The age distributions of the patients who had as the chief complaint occlusal disharmony were at the ages of 3 and 6 to 7 at the maximum. 3. The number of patients who were diagnosed with occlusal disharmony at the first examination was 28.5%. These included anterior cross-bite 32.5%, edge to edge bite 14.1%, cross-bite 13.0%, crowding 11.8% and et al. 4. The distribution of anterior cross-bites due to the developmental stage was divided into the deciduous dentition 59.9%, the mixed dentition 39.3% and the permanent dentition 0.8%. 5. The sex ratios of anterior cross-bites in the deciduous dentition were 45.6% for boys and 54.4% for girls. 6. The treatment of occlusal guidance for anterior cross-bite in the deciduous dentition started from ages 3 to 5. 7. The appliances used for the treatment of anterior cross-bite in the deciduous dentition were maxillary protraction 25.0%, the chin cap 20.0%, the FKO 17.5%, and the lingual arch with herical springs 15.0% and et al. 8. The status of the patients with the anterior cross-bite in the deciduous dentition as of August 1986 was that the 36.2% was under the observation, and 24.4% was under the treatment of occlusal guidance or under the observation after the treatment was done.

Child↗