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Biomedical subjects

M Akasaka

Publications and source records attributed to M Akasaka.

At least 19 recordsLinked to original sources
PubMed1998

Detection of in vivo genotoxicity of haloalkanes and haloalkenes carcinogenic to rodents by the alkaline single cell gel electrophoresis (comet) assay in multiple mouse organs.

The micronucleus test is widely used to assess in vivo clastogenicity because of its convenience, but it is not appropriate for some carcinogenic chemical classes. Halogenated compounds, for example, are inconsistent micronucleus inducers. We assessed the genotoxicity of 7 haloalkanes and haloalkenes carcinogenic to rodents in 7 mouse organs-stomach, liver, kidney, bladder, lung, brain, and bone marrow-using the alkaline single cell gel electrophoresis (SCG) assay. The carcinogens we studied were 1, 2-dibromo-3-chloropropane (DBCP), 1,3-dichloropropene (mixture of cis and trans) (DCP), 1,2-dibromoethane (EDB), 1,2-dichloroethane (EDC), vinyl bromide, dichloromethane, and carbon tetrachloride; only DBCP induces micronuclei in mouse bone marrow. Except for carbon tetrachloride, halocompounds studied are mutagenic to Salmonella typhimurium. Mice were sacrificed 3 or 24 h after carcinogen administration. DCP and EDC induced DNA damage in all of the organs studied. Vinyl bromide yielded DNA damage in all of the organs except for bone marrow. DBCP induced DNA damage in the stomach, liver, kidney, lung, and bone marrow; EDB in the stomach, liver, kidney, bladder, and lung; and dichloromethane in the liver and lung. Since no deaths, morbidity, clinical signs, organ pathology, or microscopic signs of necrosis were observed, the DNA damage was not attributable to cytotoxicity. On the other hand, the positive response in the liver induced by carbon tetrachloride, which was accompanied by necrosis, was considered to be a false positive response. We suggest that the alkaline SCG assay can be used in multiple organs to detect in vivo genotoxicity that is not expressed in bone marrow cells in mice given non-necrogenic doses of halocompounds.

Alkanes↗
PubMed1998

Organ-specific genotoxicity of the potent rodent colon carcinogen 1,2-dimethylhydrazine and three hydrazine derivatives: difference between intraperitoneal and oral administration.

We used a modification of the alkaline single cell gel electrophoresis (SCG) (Comet) assay to test the in vivo genotoxicity of four hydrazine derivatives--1,2-dimethylhydrazine (SDMH), 1,1-dimethylhydrazine (UDMH), hydrazine (HZ), and procarbazine (PCZ)--in mouse liver, lung, kidney, brain, and bone marrow, and in the mucosa of stomach, colon, and bladder. Mice were sacrificed 3 and 24 h after intra-peritoneal (i.p.) and oral (p.o.) administration. SDMH at 20 mg/kg i.p. yielded statistically significant DNA damage in all tested organs except for lung. In the gastrointestinal tract, SDMH was genotoxic in the stomach and the colon after i.p. treatment but only in the colon after 20 and 30 mg/kg p.o. treatment. UDMH at 50 mg/kg i.p. yielded DNA damage in the liver and lung at 3 h. PCZ at 200 mg/kg i.p. caused DNA damage in the liver, kidney, lung, brain, and bone marrow. UDMH and PCZ were positive in the stomach and colon p.o. but not by i.p. treatment. HZ at 100 mg/kg yielded DNA damage in the stomach, liver, and lung when given i.p. and in the brain when p.o. Thus, the administration route is important when evaluating organ-specific genotoxicity in multiple organs.

1,2-Dimethylhydrazine↗
PubMed1998

[A case of vertebrobasilar dissection which was associated with progressing stroke and was successfully treated by intravascular surgery in the acute stage].

A case of vertebrobasilar dissection which deteriorated in the acute stage and was successfully treated by intravascular surgery is described. A 26-year-old male presented with sudden onset of occipitalgia, weakness of the right upper and lower extremities, and speech disturbance. He was transferred to our hospital 3 hours after the onset. On admission, neurological examination showed right hemiparesis including the face and dysarthria. CT of the head showed no definite abnormality and left vertebral angiograms (VAG) revealed only slight wall irregularity of the basilar artery. T2-weighted MR imaging demonstrated an area of high intensity in the left side of the pons. He was treated conservatively under a diagnosis of pontine infarction. On the 8th hospital day, he developed left hemiparesis. T2-weighted MR imaging revealed a new high intensity lesion in the opposite side of the pons. 3D-SPGR images showed double lumen of the left vertebral artery. Angiography showed that the wall irregularity of the basilar artery had become more obvious. These findings strongly suggested a dissection extending from the left vertebral artery to the basilar artery. Progression of the dissection was presumed to have caused the worsening in clinical symptoms, and further progression of the dissection would involve perforators of the basilar artery top and would be fatal. To prevent further progression of the dissection, the left vertebral artery was occluded at the proximal site of the orifice of the dissection with platinum coils after a test occlusion on the same day. Postoperatively, further deterioration of the clinical symptoms ceased. Left VAG on the 33rd postoperative day demonstrated improvement in the wall irregularity of the basilar artery. His clinical symptoms improved markedly and he was ambulatory at discharge and returned to his previous occupation. We emphasize that a progressive vertebrobasilar dissection that causes clinical deterioration in the acute stage can be prevented from progressing further by occlusion at the proximal site of the orifice of the dissection.

Adult↗
PubMed1997

In vivo genotoxicity of ortho-phenylphenol, biphenyl, and thiabendazole detected in multiple mouse organs by the alkaline single cell gel electrophoresis assay.

In Japan, ortho-phenylphenol (OPP), biphenyl (BP), and thiabendazole (2-(4'-thiazolyl)benzimidazole, TBZ) are commonly used as a postharvest treatment to preserve imported citrus fruits during transport and storage. We used a modification of the alkaline single cell gel electrophoresis (SCG) (Comet) assay to test the in vivo genotoxicity of those agents in mouse stomach, liver, kidney, bladder, lung, brain, and bone marrow. CD-1 male mice were sacrificed 3, 8, and 24 h after oral administration of the test compounds. OPP (2000 mg/kg) induced DNA damage in the stomach, liver, kidney, bladder, and lung, BP (2000 mg/kg) and TBZ (200 mg/kg) induced DNA damage in all the organs studied. For OPP, increased DNA damage peaked at 3-8 h and tended to decrease at 24 h. For BP, on the contrary, increased DNA migration peaked at 24 h. That delay may have been due to the fact that OPP is metabolized by cytochrome 450 and prostaglandin H synthase to phenylbenzoquinone (PBQ), a DNA binding metabolite, and BP is metabolized to PBQ via OPP and m-phenylphenol. The positive response to TBZ, an aneugen, supports the in vivo DNA-damaging action of TBZ.

Animals↗
PubMed1997

In vivo genotoxicity of heterocyclic amines detected by a modified alkaline single cell gel electrophoresis assay in a multiple organ study in the mouse.

We used a modification of the alkaline single cell gel electrophoresis (SCG) (Comet) assay to test the in vivo genotoxicity of 6 heterocyclic amines, Trp-P-1 (25 mg/kg), Trp-P-2 (13 mg/kg), IQ (13 mg/kg), MeIQ (13 mg/kg), MeIQx (13 mg/kg) and PhIP (40 mg/kg), in mouse liver, lung, kidney, brain, spleen, bone marrow and stomach mucosa. Mice were sacrificed 1, 3, and 24 h after intraperitoneal injection. Trp-P-2, IQ, MeIQ, and MeIQx yielded statistically significant DNA damage in the stomach, liver, kidney, lung and brain; Trp-P-1 in the stomach, liver and lung; and PhIP in the liver, kidney and brain. None of the heterocyclic amines induced DNA damage in the spleen and bone marrow. Our results suggest that the alkaline SCG assay applied to multiple organs is a good way to detect organ-specific genotoxicity of heterocyclic amines in mammals.

Amines↗
PubMed1997

[A case of a ruptured lingual artery aneurysm treated with endovascular surgery].

A rare case of a ruptured lingual artery aneurysm treated with endovascular procedure in presented. A 67-year-old woman undergoing treatment in our hospital for right thalamic hemorrhage complained of sudden swelling in the submandibular area and breathlessness. The swelling was so rapid and progressive that her breathing was disturbed. She was intubated as soon as possible. Computed tomography (CT) showed a massive subcutaneous hematoma, extending from the left submandibular area to the neck, which had compressed the trachea to the right. CT with contrast medium showed extravasation of the medium for this lesion. Angiography showed that the aneurysm was located on the periphery of the left ingual artery. Extravasation of contrast medium from the aneurysm was also observed. We considered that direct surgery was difficult to perform safely, so we chose an endovascular procedure to treat this lesion. The lingual artery was successfully embolized using four platinum coils. No rebleeding or other complication occurred after the coil embolization. Disturbance of breathing due to air way obstruction is an important symptom of a ruptured lingual artery aneurysm. Endovascular surgery may be the first choice for treatment of the bleeding origin.

Aged↗
PubMed1997

[Discharge program to facilitate home care of patients with respirator].

We have introduced a program to provide home care for the patient with an artificial respirator, and have used it for patients with amyotrophic lateral sclerosis (ALS). This program urges us to keep a good relationship with home care nurses, medical engineers and medical social workers, and also relieves the patient and patient's family from anxiety. It also tells us how to remove the patient's sputum, how to differentiate sterilized materials from non-sterilized, and so on. This program has been carried out successfully, resulting in the patient's early discharge from the hospital. The patient is now enjoying a comfortable life at home with the aid of an artificial respirator. We conclude that this program is useful for such a patient and his family through the smooth introduction of home care, will increase the quality of the patient's life, and will achieve an early discharge.

Aged↗
PubMed1994

Contingent negative variations associated with jaw opening in humans.

We examined the relationship between contingent negative variation (CNV) amplitude and digastric muscle activity in jaw-opening motor task. Subjects were instructed to open their jaws in response to a sound stimulus following a visual warning stimulus. Electroencephalograms were averaged by using the visual stimulus pulse as a trigger. Bilateral CNVs were clearly recorded at several cortical locations, with a tendency for larger amplitudes at temporal placements.

Adult↗
PubMed1991

Cortical potentials associated with voluntary biting movement in humans.

We compared the distribution of Bereitschaftspotentials (BPs) on both sides of the scalp preceding jaw biting movements in order to identify the relationship between the cortical regions and the activation of the masseter muscle in 10 healthy subjects. The BPs were recorded from the midline-central, central and temporal areas of the scalp according to the international 10-20 system, preceding self-paced biting on one side. The cortical negative potentials began 1.0 approximately 1.5 s before the EMG onset of the masseter muscle. All of these negative potentials could be considered to be BPs, and the additional negative slope component (NS) occurred 70 approximately 80 ms before the EMG onset of the masseter muscle. The BPs were detected from all the recorded regions of the scalp, while the NS was observed only from the bilateral temporal area. The amplitudes of BPs and NSs were largest in the temporal areas (T3 and T4) that were ipsilateral to the biting. The rates of occurrence of NS at T3 and T4 ipsilateral temporal areas were 80% and 60%, respectively. These results suggest that unilateral biting movements may be controlled mainly from the ipsilateral hemisphere.

Adult↗
PubMed1991

[Somatosensory evoked potentials by mechanical stimulation of tooth in humans].

We examined topographical analysis of the PM-SEP (periodontal mechanoreceptor-sensory evoked potential) inducing by mechanical stimulation of the tooth in eight subjects. Sensory evoked potential were recorded from various regions of the scalp by the mechanical stimulation of the normal tooth. Eleven electrodes were placed according to the International 10-20 system (T3, T4, C3, C4, T5, T6, F7, F8, Fz, Cz, Oz). The mechanical stimulation was applied to the right upper first incisor tooth. PM-SEPs were averaged 100 times following the mechanical stimulation of the tooth produced six waves of SEP at the ipsilateral temporal area (T4), but did not evoked any potential from the other regions. PM-SEP included I, II, III, IV, V and VI. The earliest latency (I wave) was approximately 11ms and latest latency (VI wave) was approximately 40 ms. These PM-SEP observed by intensity with 3 times of the threshold. In addition, the all components were abolished after local anesthesia of the periodontal ligament. These data suggests that the six waves of the PM -SEP were evoked the ipsilateral temporal region following mechanical stimulation of the tooth, and these regions were projected by afferent impulse from the periodontal mechanoreceptor.

Adult↗
PubMed1990

Primary structure of human plasma glutathione peroxidase deduced from cDNA sequences.

Human plasma glutathione peroxidase (GSHPx) has been shown to be a selenium-containing enzyme immunologically distinct from cellular GSHPx. Oligonucleotide probes, based on the partial amino acid sequence of plasma GSHPx, were synthesized and used to screen a human placenta cDNA library. Nucleotide sequence analysis of the obtained clones revealed that GSHPx consisted of a 678-base pair open reading frame coding for a 226-amino acid polypeptide with a Mr of 25,389. About 50% of the deduced amino acid sequence was confirmed by partial amino acid sequencing of the peptides in a lysine endopeptidase-digest of the purified enzyme. The amino acid sequence exhibited only 44% homology with that of human cellular GSHPx. Northern blot analysis revealed a single transcript of 2.2 kilobases in the poly(A)+ RNA fractions of human placenta and HepG2 (a human hepatic cell line), but not that of human liver and endothelial cells.

Amino Acid Sequence↗
PubMed1990

[Frequency of the developmental disturbances of tooth structure].

In permanent and deciduous dentitions, the frequency of congenitally missing teeth, supernumerary teeth, conical teeth, fused teeth, germinate teeth, abnormal tubercles (basal ridge of incisor or canine, central cusps of molars, Carabelli's cusp, protostylid, and para-molar tubercles), and enamel hypoplasia (white spots, pigmentation, and enamel defects) were surveyed. Furthermore, mesio-distal and bucco-lingual dimensions of the crowns were measured and the relationship between developmental disturbances of dental hard tissue and tooth size was examined. For the deciduous dentition, the frequency of children with congenitally missing teeth, conical teeth and fused teeth was 7.2%, 1.1% and 5.3%, respectively. Enamel hypoplasia appears with the following frequency; white spots (16.0%), pigmentation (6.4%), and enamel defects (5.2%). Mesio-distal widths of the upper canine and lower lateral incisors of the children with congenitally missing teeth was significantly smaller than the standard values. For the permanent dentition, congenitally missing teeth, conical teeth and fused teeth were detected in 5.7%, 3.0%, and 0.5% of the children, respectively. The frequency of children with basal ridge, central cusps, Carabelli's cusp, protostylid, and para-molar tubercles was respectively, 1.1%, 2.6%, 7.1%, 0.3% and 1.3%. Children with central cusps or Carabelli's cusp tended to have larger crowns, while children with congenitally missing teeth or conical teeth tended to have smaller teeth. As for enamel hypoplasia, white spots were detected in 24.9% of the children, and pigmentation was in 8.1%, and enamel defects were in 9.2%. These results indicate that abnormality of tooth number and tooth morphology correlate with the tooth size and this tendency is more striking in permanent dentition than in deciduous dentition.

Child↗
PubMed1990

[Application of the Ricketts analysis to children in the primary dentition. Fourth Report: development of lateral cephalogram analysis system and consideration of facial pattern].

A lateral cephalogram analysis system has been developed allowing an extended application of the Ricketts analysis to primary dentition. Using this system, we first examined the growth of facial patterns from the BA-NA ratio profilograms. As samples, we used records of children with normal occlusions stored at Nihon University School of Dentistry Department of Pedodontics. We then used the Fuzzy theory to change Vert's formula and obtained facial types. Lastly, we obtained compositional ratios of facial types within each age group. The results were as follows: 1) Facial patterns tended to show three divisions according to three age groups; from 3 to 5-year olds, from 6 to 7-year olds and from 8 to 10-year olds. 2) The Vert's values of the BA-NA ratio profilograms in each age group based on the data of 9-year olds tended to decrease as age increased. The change was mostly restricted to the range of Mesiofacial type. 3) As for the compositional ratio of facial types in each age group, a nearly normal distribution was observed mainly with the Mesiofacial type. 4) From the lateral cephalogram analysis system which has been developed and the profilograms of the average values for each age group which have been obtained by this system, we obtained the standard values for future evaluation of facial patterns of children with malocclusions.

Age Factors↗
PubMed1990

[The management of drooling in patients with cerebral palsy--submandibular duct relocation].

Drooling is a significant problem demonstrated by individuals of all ages with a variety of etiologies such as neurological disorders, cerebral palsy, mental retardation and others. Persistent drooling not only creates troublesome hygienic problems for patients, teachers, nurses, and playmates because of the constant soiling of clothes, toys, and work materials, but also causes an odor from their clothing and bibs. The older patient with normal cognition is disturbed by the drooling and may become depressed and reclusive. Successful management of drooling alleviates these problems, improves appearance and self-esteem and significantly reduces the time involved in the care of the sufferers. The author, who had studied at the University of Toronto for 2 years, acquired the technique of submandibular duct relocation under the guidance of Dr. Crysdale. We carried out the surgical procedure of submandibular duct relocation for drooling on six patients who had cerebral palsy. The surgical procedure resulted in a dramatic decrease in drooling and odor levels. All of them improved in appearance, and the time involved in the care of the suffers was significantly reduced. The complication of ranula, however, appeared in two cases, which suggested a much higher frequency than that in the report of Crysdale. It seems that a detailed explanation to parents and teachers about the advantages and disadvantages of submandibular duct relocation is important.

Cerebral Palsy↗
PubMed1989

Distribution of movement-related cortical potential upon jaw-biting in humans.

We examined the cerebral location of the readiness potential (hereinafter referred to as "RP") upon activation of the masseter muscle by voluntary and unilateral jaw-biting movement. Four normal adults served as subjects. Five scalp electrodes were placed according to the international 10-20 method at CZ, C3, C4, T3 and T4. In addition, in one of the subjects, RPs were recorded by 12 scalp electrodes in order to study changes occurring in the distribution of RPs with time. The maximum amplitude of the RP was located at T4 in the temporal area, which was involved in the biting movement as a negative slow potential occurring 1.4-0.8 s before the beginning of the discharge to the masseter muscle. The maximum amplitude of the RP on the contralateral side was located at T3. This meant that the amplitude of the RP tended to be higher on the same side as the biting movement than on the contralateral side in all subjects. From scalp topography, the maximum amplitude of the RP was shown to be confined to T4, and was especially marked immediately before the beginning of discharge to the masseter muscle. From these results it is thought that in the case of voluntary biting movement, the RP reflects activities of the pyramidal cells in the masticatory area of the cortex, and that strong descending impulses from both sides then reach the masseter muscles.

Action Potentials↗
PubMed1989

[Survey on nutrition of infants in the Tokyo metropolitan area. 1. Carious dentitions, anomalies of occlusion and ways of eating].

In September, 1987, a survey on the nutrition of infants was conducted with 1,235 children from 3 to 6 years of age selected from six nurseries and six kindergartens in the metropolis of Tokyo. We compared the survey results with other similar survey reports with respect to three areas; 1, caries attack on primary teeth, 2, anomalies of dentition and occlusion and 3, how foods are eaten, to observe the difference by age and also between children in nurseries and in kindergartens. The following are the results of this comparative investigation. 1) The ratio of caries attacks on the 4-year-old in this survey was 69.6%, which was lower than the 83.4% of the nationwide survey of 1987 conducted by the Ministry of Health and Welfare, while the average value of the df index per person was 4.7, which was lower than the 6.1 of 1981. 2) The caries incidence rate was higher with children in kindergarten than those in nurseries and many kindergarten children had had more than one caries attack. 3) The frequency rate of anomalies of dentition and occlusion in the entire survey sample was 12.9% for deep overbite, 11.4% for open bite and 10.7% for edge-to-edge bite. 4) In the survey of how foods were eaten, the question, "Does your child like to eat things that are hard to bite on?" was asked, and 10.4% of the group answered "My child prefers eating soft food," which was quite high. To the question, "Does your child often eat things that are difficult to eat?", 17.1% of the entire group answered, "My child refuses to." This tendency was greater among the children in kindergaretens.

Child, Preschool↗