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Biomedical subjects

K Furusawa

Publications and source records attributed to K Furusawa.

At least 37 records · Page 2Linked to original sources
PubMed1998

Oxidation of cysteamine induced by gas-phase radicals from combustion smoke of poly (methyl methacrylate).

In order to obtain fundamental knowledge on biological damage caused by the smoke from combustion of poly(methyl-methacrylate) (PMMA), we investigated the oxidation of cysteamine induced by PMMA smoke. We suggest that the long-lived and oxygen-centered radicals involved in PMMA smoke should play an important role in the oxidation of cysteamine. The mechanism for the oxidation of cysteamine by combustion smoke of PMMA was postulated as radical initiated chain reactions, taking into account the effect of pH, oxygen and radical concentrations.

Chromatography, High Pressure Liquid↗
PubMed1998

Effects of N-[2-(1-azabicyclo[3,3,0]octan-5-yl)ethyl]2-nitroaniline fumarate (SK-946), a novel cognition activator, on learning and memory in rodent models.

We examined the effects of N-[2-(1-azabicyclo[3,3,0]octan-5-yl)ethyl]2-nitroaniline fumarate (SK-946) on cognition in various rodent models. SK-946 slightly suppressed spontaneous motor activity, but had no effect on scopolamine-induced motor facilitation. SK-946 ameliorated scopolamine-, pirenzepine-, cycloheximide- and electric shock-induced passive avoidance deficits in rodents when administered before acquiring the training. In an active avoidance test, SK-946 accelerated avoidance acquisition in the later half of training without a marked increase in lever-pressing. In more reliable models of cognitive disorders, i.e. an AF64A intracerebroventricular infusion model using the step-through passive avoidance test, an aged rat model using the step-down passive avoidance test and methylazoxymethanol (MAM)-induced microencephalic rat model using the Morris water maze test, SK-946 ameliorated impaired learning and memory. These results suggest an ability of SK-946 to enhance cognitive functions.

Aging↗
PubMed1998

Characterization of the neurochemical effects of N-[2-(1-azabicyclo[3,3,0]octan-5-yl)ethyl]2-nitroaniline fumarate (SK-946) as a cognition activator.

The neurochemical effects of SK-946, N-[2-(1-azabicyclo[3,3,0]octan-5-yl)ethyl]2-nitroaniline fumarate, were investigated in an attempt to elucidate cognition activating properties. In rat brain cortical membranes and in cloned human receptors expressed in Sf9 cells, SK-946 had submicromolar affinities for muscarinic receptors with a moderate selectivity for M1 (m1) sites. Although no increase in the antagonist (N-methylscopolamine)/agonist (oxotremorine-M) binding ratio was observed, SK-946 exhibited a partial agonistic effect on receptor-stimulated phosphoinositide hydrolysis in primary cultured rat fetal hippocampal cells. Heterogeneous, reversible and concentration-dependent excitations of the hippocampal neuronal cells treated with SK-946 (10(-5)-10(-3) M) were confirmed as increases in cytosolic Ca2+ concentrations measured in Fura-PE3 preloaded cells. Furthermore, SK-946 (>10(-5) M) increased [3H]myo-inositol uptake into the hippocampal cells. On the other hand, SK-946 had no effect on adenylate cyclase activities in primary cultured rat heart cells, and showed a weak antagonistic effect on carbachol-induced adenylate cyclase inhibition, suggesting that it is an M2 antagonist. Using in vivo microdialysis, it was found that relatively low concentrations (<10(-7) M) of SK-946 increased acetylcholine release and decreased choline content in that hippocampal area in rats. These results suggest that SK-946 accelerates muscarinic neuronal transmission in the central nervous system.

Acetylcholine↗
PubMed1997

Remaining mandibular third molars in an adult population.

Although tooth loss with age has been extensively investigated, there appears to be no literature on the relationship of age to remaining mandibular third molars. The study showed that as age increases so does the frequency of absent vertically erupted mandibular third molars. However, no correlation was found between age and loss of mandibular impacted third molars in men of 71 years of age or older. The evidence presented here suggests that impacted mandibular third molars, which have not been infected, may be more likely to remain compared with other teeth at potential risk.

Adult↗
PubMed1997

Unerupted canine without median diastema.

The eruption of the canine is known to be a factor for diastema closure. In this study the relative changes in the orientation of the unerupted canine were assessed using the orthopantomographs of 9854 patients who sought consultation between April 1984 and March 1993. A total of 38 canines in 32 patients, all aged 11 years or older, were identified as unerupted canines. The features of the patients with unerupted canine showed no significant relation to diastema closure status, but some patients had unerupted horizontal or inverted canine without diastema even in the absence of a history of orthodontic treatment, suggesting the presence of a mechanical force due to some phenomenon other than canine eruption as a factor in diastema closure.

Adolescent↗
PubMed1997

Responses to conservative treatment in temporomandibular disorders with locking versus with muscle pain.

We conducted a follow-up study of 150 patients with temporomandibular disorders, of whom 91 had muscle pain and 59 locking, in order to investigate the response to conservative treatment. The patients with muscle pain showed fairly uniform age distribution, while the percentage over 49 years of age was lower in those with locking. Of the patients with TMJ locking, the percentage who completed treatment was high, and the duration of treatment in this group was longer than that in those with muscle pain. The differences between these patient groups in the response to conservative treatment may be useful in the assessment of individual patients with temporomandibular disorders. Moreover, the greater incidence of completion of conservative treatment in the patients with locking indicates that these patients should be treated by conservative treatment prior to surgical treatment.

Adolescent↗
PubMed1997

Incidence of inflammation in completely impacted lower third molars.

The influence of ageing and the contact of the adjacent tooth on purulent inflammation associated with the completely impacted lower third molar was assessed in 26 patients with clinical symptoms of infection out of 800 patients who had roentgenographically-confirmed completely impacted lower third molars. These 26 patients were 23 years of age or older. The 9 with pain alone ranged from 25 to 44 years of age, whereas the 17 patients with inflammation ranged from 29 to 67 years of age, and non-contact to adjacent tooth was associated with purulent inflammation in older patients, indicating completely impacted lower third molars may cause pain only until 45 years of age; but purulent inflammation occurs even in the group of non-contact to adjacent tooth after 45 years of age. The authors recommend that a completely impacted lower third molar should be removed if the risk factors of advanced age and contact with the adjacent tooth are present.

Adult↗
PubMed1996

Central distribution and peripheral functional properties of afferent and efferent components of the superior laryngeal nerve: morphological and electrophysiological studies in the rat.

The central distribution of the afferent and efferent components of the superior laryngeal nerve (SLN), which in the rat is ramified into the three branches of the rostral branch (R.Br), middle branch (M.Br), and caudal branch (C.Br), was examined after application of horseradish peroxidase conjugated with wheat germ agglutinin (HRP-WGA) to the proximal cut end of each branch. In addition, the afferent and efferent neural activities of each branch were recorded to investigate the functional properties. The present study provided several new findings as to the distribution of each branch and the functional properties of the SLN. The following conclusions were drawn: 1) the R.Br, containing only afferent fibers projecting to the ipsilateral lateral region of the nucleus of the solitary tract (NST), extends between slightly below the obex and the region approximately 0.6 mm rostral from the obex, and it corresponds to the interstitial subnucleus of the NST; 2) the M.Br, innervating the cricothyroid muscle, contains only efferent fibers originating ipsilaterally from the motoneurons localized within the ambiguus nucleus (Amb) and in the area ventrolateral to the Amb; and 3) the C.Br, which innervates the inferior pharyngeal constrictor muscle, contains both efferent and afferent fibers. HRP-WGA-labeled cells are distributed within both the Amb and the dorsal motor nucleus of the vagus nerve, ipsilateral to the injection site. Afferent proprioceptive fibers project to the ipsilateral interstitial subnucleus of the NST. The present results provide evidence that each branch of the SLN has distinctive functional properties and contributes to the laryngeal functions.

Afferent Pathways↗
PubMed1996

Completely impacted teeth in dentate and edentulous jaws.

Panoramic radiographs from 1026 patients were examined for the presence of completely impacted teeth. The prevalence of completely impacted teeth in the edentulous jaw was lower than that in the dentate jaw in both the upper and lower jaws. The prevalence of completely impacted third molars in the edentulous jaw was also lower than that in the dentate jaw. However, there was no difference in the prevalence of completely impacted canine teeth and completely impacted anterior maxillary supernumerary teeth (mesiodens) in the edentulous jaw. These findings may indicate that completely impacted canine teeth and impacted anterior maxillary supernumerary teeth (mesiodens) are not influenced by the loss of erupted teeth.

Adult↗
PubMed1996

Proprioceptive representation of the levator veli palatini muscle in the solitary nucleus of the rat.

The levator veli palatini muscle is innervated by motoneurons of the glossopharyngeal nerve, which are located within the ambiguus nucleus; however, little is known about the afferent fibers of this muscle. A horseradish peroxidase study was conducted in rats following injection into the levator veli palatini muscle branch to reveal the location and the distribution of dendrites of the afferent fibers of the muscle. Terminal labels were densely distributed in the lateral region of the solitary nucleus, which receives afferents of the glossopharyngeal nerve, ipsilateral and contralateral to the injection site. The relationship of the levator veli palatini muscle with respiration was suggested by the localization of labeled terminals at sites where the afferents from the respiratory organs project densely, and by the demonstrated proprioceptive role of the afferent fibers passing through the muscle spindles contained in the levator veli palatini muscle.

Afferent Pathways↗
PubMed1995

Radiographic study of bone loss of mandibular lingual cortical plate accompanied by third molar development.

OBJECTIVE: The purpose was to determine the features of mandibular lingual cortical bone loss around the root of the mandibular third molar. STUDY DESIGN: We examined occlusal radiographs in 2210 persons aged 11 to 78 years. RESULTS: Prominent increase of incidence of bone loss was evident in subjects in their third decade compared with those in their second decade. The incidence was not decreased into the sixties. The incidence of bone loss in men was significantly higher than that in women. The incidence was not influenced by inflammation around the tooth crown of the third molar, by tooth caries, or by metal fillings present in the third molar. CONCLUSIONS: The present observations suggest that bone loss is induced by physiologic processes that accompany root formation of the third molar after mandibular growth.

Adolescent↗
PubMed1995

Influence of adjacent teeth on impacted third molars in the upper and lower jaws.

Panoramic radiographs of 1834 patients older than 21 years were evaluated for the prevalence of impacted teeth at different ages. The frequency of impacted teeth by age was constant, that is, the presence of completely impacted teeth could not be related to age. The interrelationship between the angulation of impacted teeth and the existence of adjacent teeth was studied in individuals older than 61 years. The angulation of most of the completely impacted teeth in the upper-third molar region was horizontal when adjacent teeth were not present, whereas impacted teeth in the upper-third molar region showed vertical angulation when adjacent teeth were present, suggesting that vertically impacted teeth may become exposed by bone resorption or infection and should be removed. The angulation of impacted lower third molars was horizontal irrespective of the presence of adjacent teeth. It appears that the interrelationship between the angulation of completely impacted teeth and the presence of adjacent teeth is different between the upper and lower third molar regions. The angulation of completely impacted teeth and the presence of adjacent teeth should be included in those criteria which determine whether or not completely impacted teeth should be removed.

Adult↗