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Biomedical subjects

M Kaga

Publications and source records attributed to M Kaga.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Evaluation of cytotoxicity of VLC Dycal in tissue culture for clinical use].

The purpose of this study was to evaluate the VLC Dycal (visible light cured composite-calcium hydroxide material) to see whether it is suitable or not as a direct or indirect pulp capping agent for clinical use by means of the cell culture test. Two light cured composite resins, P-30 and Silux, and also Dycal and Ca(OH)2 were used as a control for a comparative cytotoxicity test with VLC Dycal. All test materials were put into the glass tubes (4 mm diameter X 1 mm high), then illuminated for 10, 20, 30, 40, 50 and 60 seconds through a matrix strip with direct contact with a Prisma-light source (L.D. Caulk), just before testing. Fibroblasts, 5 ml of 1 X 10(5) cells per ml in Eagle's MEM medium with 10% FCS, penicillin (100 U/ml) and streptomycin (100 micrograms/ml) were evenly seeded on a cover glass in a tissue culture dish and incubated for 24 hours at 37 degrees C in a humidified atmosphere of a 5% CO2 in air. After 24 hours, the medium was replaced with 5 ml of agar overlay medium consisting of 10% FCS, Eagle's MEM medium and 1.5% agar. Glass tubes (n = 8) filled with the test materials were placed at the center of the agar, and incubated for 24 hours in 5% CO2 in air at 37 degrees C. After 24 hours of incubation, the cover glass was removed and the cells were fixed in 10% neutral formalin and then stained by H.E. to differentiate the areas of affected and unaffected cells beneath the test specimens. The affected area was quantitatively determined using an image analysis system.(ABSTRACT TRUNCATED AT 250 WORDS)

Bisphenol A-Glycidyl Methacrylate↗
PubMed1989

[Clinical diagnoses of pediatric patients without detectable auditory brainstem response (ABR)].

One hundred and forty-seven out of 1,600 infants and children showed no detectable ABR. ABRs were evoked by clicks. As to hearing acuity, 121 out of 147 patients had sensorineural hearing loss and 19 had no hearing impairment of high frequency (3-4 kHz) and high sound intensity (85-90 dBnHL). Eight patients could not be diagnosed whether they had hearing impairment or not. Among 19 patients who did not have sensorineural hearing loss in those ranges described above, 5 patients had cerebral palsy with severe mental retardation, 4 had mitochondrial encephalomyopathy, 3 had degenerative disease of unknown etiology, 2 patients had Down syndrome, 1 was a low birth weight infant with respiratory distress syndrome, 1 was a neonate born to a diabetic mother, 1 experienced severe neonatal asphyxia, 1 patient had acute lymphoblastic leukemia and 1 infant was later confirmed as a healthy girl. Of these, four patients showed transiently negative response in ABR. Nine patients remained undiagnosed as to hearing because they were in deep coma, had profound brain damage, or died in early neonatal period. They had major neurological diseases: severe neonatal asphyxia, holoprocencephaly, microcephaly, degenerative diseases of the central nervous system of unknown origin, metachromatic leukodystrophy, trisomy of chromosome 18, anoxic encephalopathy, small for gestational age newborn with intracranial bleeding and posthemorrhagic hydrocephalus. When ABR cannot be recorded using high sound intensity clicks, it usually suggests presence of hearing impairment of high frequency range. However, there are patients who have no hearing impairment in those sounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1988

Cytotoxicity of amalgams.

The purpose of this study was to compare the relative cytotoxicity of amalgams and to determine whether their toxicity depends upon composition and aging time, by means of a rapid and sensitive in vitro cell culture test. Zinc-containing amalgams showed higher cytotoxicity than did any other amalgams. High-copper amalgams had the same cytotoxicity as did the low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. Moreover, excessive additions of selenium increased the cytotoxicity of amalgam compared with that of a similar selenium-free material. The cytotoxicity of amalgam was decreased with aging time, possibly due to the combined effects of surface oxidation and further amalgamation.

Cells, Cultured↗
PubMed1985

[Study on toxicity of halopredone acetate. (I) Acute toxicity study in mice and rats].

Since halopredone acetate (THS-201), a synthetic corticosteroid, is expected to be used clinically for intra-articular injections because of its long-lasting activity in the synovial bursa, its acute toxicity was compared with that of triamsinolone acetonide (TA) and methylprednisolone acetate (MPA). The test animals were Jcl: ICR mice and Jcl: Wistar rats, and drugs were administered orally, intraperitoneally and subcutaneously. The LD50 values of THS-201 both in mice and rats were estimated more than 5000 mg/kg at each route, and these are for above larger than those of TA or MPA. Moreover, in oral and subcutaneous administration of THS-201, no severe toxic signs were observed either in mice or in rats. In intraperitoneal injection, a few of mice and rats died after showing several clinical signs and suppression of body weight gain, and their autopsy revealed atrophy of thymus, spleen and adrenal, induction of infection and hemorrhage in digestive tract. On the other hand, the mice and rats administered TA or MPA revealed the severe toxic signs such as loss of hair gloss, marked emaciation, decrease in spontaneous movement, anemia, bloated face, decrease or suppression of body weight gain, atrophy of thymus, spleen and adrenal, severe induction of infection and lesions in digestive tracts. Accordingly, it is concluded that the acute toxicity of THS-201 in mice and rats was lower than that of TA or MPA.

Administration, Oral↗
PubMed1984

Normalization of poor auditory brainstem response in infants and children.

In these past 10 years, the usefulness of auditory brainstem response (ABR) has been demonstrated in the clinical evaluation of audiological or neurological disorders, and the absence of an ABR is commonly accepted as consistent with a peripheral hearing loss caused by middle or inner ear diseases. In this article, the authors report nine infants and children who had an absent or difficult to detect ABR at the first examination with subsequent normalization of ABR. Repeated otological examinations were always normal in these patients. The final diagnoses were delayed development, Waardenburg syndrome with congenital heart disease and epilepsy, healthy infant, infantile convulsion, mental retardation with history of low birth weight, in each case, and chromosomal aberration in four patients. The reason for normalization of ABR in our patients is not clear and is yet to be ascertained. However, the authors believe that neurological maturation rather than an improved primary peripheral disorder is responsible for the noted normalization of the ABR, because of the high incidence of neurological abnormalities in these patients.

Audiometry, Evoked Response↗
PubMed1984

[Chronic toxicity study of AC-1370 sodium, an antibiotics, intravenously administered in rats].

A study on chronic toxicity of AC-1370 sodium (AC) in addition to recovery from its toxicity, was carried out using the rat. AC was administered to the rat through the tail vein in doses of 30, 100, 300 and 1000 mg/kg body weight/day, with the periods for administration and recovery being 26 and 13 weeks, respectively. The results obtained from the present study were as follows. In each group, neither death case nor fatal damage was observed throughout the whole process. In the group of 1000 mg/kg, the below findings were observed in one or both sexes: suppression in increase of body weight, increases in drunk amount of water, urinary volume and urinary excretions of electrolytes, degeneration in renal tubules and several correlated changes, tendency of anemia, changes in serum biochemical tests, and changes in each organ weight. In the group of 300 mg/kg, the above findings were observed slightly in comparison to the group of 1000 mg/kg. In the groups of 100 and 30 mg/kg, any changes suggesting the damages were not observed. In the recovery test, the group of 1000 mg/kg was found to be incompletely restored from the damages, with the partially residual damages being shown. In contrast, the group of 300 mg/kg showed to be almost restored from the damages. These results denotes that the maximal non-toxic dose of AC in this study is 100 mg/kg/day in long-term administration.

Animals↗
PubMed1983

A recognizable pattern of the midface of retinoblastoma patients with interstitial deletion of 13q.

In our study, we found a recognizable pattern of the midface in three retinoblastoma patients with interstitial deletion of chromosome 13 in lymphocytes. Further photographs of patients reported by other authors confirmed our conclusion that the midface in children with interstitial deletion of 13q from q12 to q22, always involving q14, is characterized by prominent eyebrows, broad nasal bridge, bulbous tip of the nose, a large mouth with a thin upper lip, and a long philtrum. This midface pattern could not be recognized in patients with normal karyotypes, suggesting that the critical segment for the midface phenotype as well as for retinoblastoma may exist in band 13q14.

Child, Preschool↗
PubMed1983

[Acute toxicity of intrarectally administered (ketoprofen (T10) in rat weanlings].

Acute toxicity of Ketoprofen, a nonsteroidal antiinflammatory analgestic, was studied using rat weanlings. Ketoprofen was intrarectally administered in the form of a mixture with T10, a basic materials for suppositaries. The results obtained were as follows: LD50 of KP was estimated to be 434 mg/kg in male weanlings and 496 mg/kg in female weanlings. These values were about four times higher than those obtained from our previous study (Shimpo et al., 1981) using six-weeks old adult rats of both sexes. The fact indicated that rat weanlings were far tolerant to KP intrarectally administered than young adult rats. Intrarectal administration of KP at high doses, caused death between the second and the seventh day after administration. Gross and histopathological examinations revealed that dead weanlings carried perforative peritonitis with ulcers mainly in jejunum and ileum not in rectum. It was therefore suggested that the ulcer was produced in small intestine by entero-hepatic circulation of KP and finally mortal peritonitis occurred.

Age Factors↗
PubMed1983

[Carcinogenicity study of cholestyramine in rats].

Carcinogenicity study on cholestyramine, an anti-hypercholesterolemic agent, was carried out using Fischer rats by feeding with a normal pellet diet (control) and with three sorts of the pellet diets in which cholestyramine was admixed in the common diet at the rates of 1.25, 2.5 and 5%, respectively. The animals were fed with these diets for 26 months and a normal diet for subsequent 2 months. Some of the male rats fed with the 5% admixed diet revealed a slight growth retardation and occasionally hemorrhagic tendency, without resulting in severe macroscopic and microscopic lesions of the internal organs and in shortening of the mean survival time as compared with that of the control group. The rates of tumor-bearing animals were high in all experimental groups including the control, but the rates were not considered to be drug-related. Incidences of individual tumors were not significantly different each other between cholestyramine-fed groups and control group. Thus, it was not recognized that cholestyramine induced any drug-related specific tumors and an accelerated growth of any tumors.

Animals↗
PubMed1983

[Chronic toxicity study of ranitidine hydrochloride orally administered in rats].

Chronic toxicity of ranitidine hydrochloride, a new histamine H2-receptor antagonist, was studied using Sprague Dawley rats. Ranitidine was administered orally at dose levels of 30, 100, 300 and 1000 mg/kg/day for 26 or 53 weeks. In the 1000 mg/kg/day group, ten of 31 females died showing acute toxic signs. In the survived animals of this dose group, changes were observed, such as salivation, depression of body weight gain, increase in water consumption, increase in urinary Na and K excretion, increase in serum albumin content, increase in weights of the liver, kidneys and heart. Main histopathological findings were as follows: centrolobular or midzonal fat deposition in liver, increase in s-ER in hepatocytes, increase in foamy cells in lung and some slight degenerative changes occasionally seen in renal tubules. In the 300 mg/kg/day group, the changes similar to those in the 1000 mg/kg/day group were observed, however, the degree of these changes was more moderate. All of the above-mentioned findings were demonstrated to be reversible in recovery period for 8 weeks. In the 100 and 30 mg/kg/day groups, no remarkable changes were observed in both sexes. It was concluded that the maximum nontoxic dose of ranitidine hydrochloride was 100 mg/kg/day in male and female rats.

Administration, Oral↗