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Biomedical subjects

T Serikawa

Publications and source records attributed to T Serikawa.

At least 163 records · Page 9Linked to original sources
PubMed1981

Long-term observation of canine brucellosis: excretion of Brucella canis into urine of infected male dogs.

Six male dogs orally inoculated with 3.2 X 10(8) Brucella canis and 2 male dogs naturally infected with the organisms were examined weekly for the presence of the organisms in urine and blood as well as for agglutinin titers in serum. Excretion of the organisms into urine started on 1 to 3 weeks after onset of bacteremia, i.e. 4 to 8 weeks after inoculation, and lasted for about 1 to 1.5 years. Non-bacteremic intervals, intermittent or lasting for about 1 to 6 months, followed the initial period of abundant excretion of viable organisms in urine. The highest urinary concentrations of the organisms, 2.5 X 10(4) to 1.5 X 10(6) cells per ml, were obtained in all dogs between the 6th and 14th weeks after the oral inoculation. Serum agglutinin titer rose on the 3rd to 5th weeks after the inoculation and then the titers remained at 1 : 640-1 : 2,560. The titers showed a downward trend over the 40 th to 56th weeks after the inoculation. In one of the spontaneously infected cases, the organisms were demonstrable only from urine for half a year with suspicious serum agglutinin titer of 1 : 160 after the bacteremic phase.

Agglutination Tests↗
PubMed1978

Sporulation and C2 toxin production by Clostridium botulinum type C strains producing no C1 toxin.

All of the 8 strains that were previously assumed to be nontoxigenic Clostridium botulinum type C were re-examined for their toxigenicity and were demonstrated by trypsinization of the culture filtrates to produce C2 toxin under improved cultural conditions. One per cent glucose added to trypticase peptone medium enhanced C2 toxin production. The larger the spore population, the higher the C2 toxicity and when spore population was smaller than a level of 10(4)/ml, no C2 toxicity was demonstrated. The C2 toxin was produced only during sporulation and not during vegetative growth.

Clostridium botulinum↗
PubMed1977

[A new microtiter plate agglutination method for Brucella canis antibodies (author's transl)].

A micro-agglutination test method for detecting antibodies to Brucella canis was developed. Heat-killed Brucella canis antigens were diluted to an optical density of 0.8 at 420 nm using a spectrophotometer. A volume of 0.025 ml of the antigen was incubated with the same volume of serially diluted sera for 18 to 24 hr at 37 C. Titers of selected dog sera obtained by the present micro-test method were well correlated with those obtained by the classical tube test with satisfactory reproducibility. The micro-test method is more advantageous for screening the antibodies of dog sera because the test can be performed with: (1) smaller volume of the test sera and the antigen (2) shorter period for incubation, and (3) lesser labor.

Agglutination Tests↗
PubMed1976

Persistent high numbers of Clostridium perfringens in the intestines of Japanese aged adults.

TSN agar was applicable for enumeration of Clostridium perfringens in fecal samples of adults but not in those of infants. It was demonstrated using TSN agar that some healthy aged adults had persistently carried C. perfringens at levels ranging from 10(7) to 10(9), while some others ranged from 10(3) to 10(6) per ml volume of fecal sample although all of these adults had the same diets. In the test for agglutinability of isolates of C. perfringens collected from two elderly adults, a younger adult and a baby, it was demonstated that most of the isolates obtained from an aged adult of high levels for 19 months belonged the same serotype, while rapid alteration of serotypes could be observed in three other persons with high or low levels. In spite of as many as 10(9) C. perfringens per ml of feces, no trace of a-toxin could be detected in the fecal samples. In in vitro tests, fecal suspension suppressed the production of a-toxin although it allowed the organism to grow sufficiently.

Adult↗
PubMedDate not supplied

Epileptic seizures in rats homozygous for two mutations, zitter and tremor.

In the rat, zitter (zi) and tremor (tm) are autosomal recessive mutations that in homozygotes caused curled whisker hair, and tremor when the animals move. In both mutant types, the presence of many vacuoles gives the central nervous system a spongy appearance. The mutants differ sharply in one important characteristic: zitter rats are fertile, tremor rats are sterile. The F1 hybrids between zitter homozygous females and a tremor heterozygous male were all normal, and data from subsequent crosses revealed that zi and tm are neither allelic nor linked to each other. In animals homozygous for both mutations, an epileptic seizure frequently and spontaneously occurred from 7 or 8 weeks of age. Although the epileptic seizure has not been studied in detail, it may be an excellent animal model of epilepsy.

Alleles↗
PubMedDate not supplied

Assignment of tremulous body mutant gene zitter (zi) to linkage group IV of the rat (Rattus norvegicus).

Zitter rats are mutants from a Sprague-Dawley rat colony. They exhibit whole body tremors, defective overhairs, bent whiskers, and spongiform encephalopathy of the central nervous system. The anomalies are caused by an autosomal recessive gene, zitter (zi). We examined the linkage relationships between zi and 14 polymorphic loci in two backcross series, (zitter x TM)F1 x zitter and (zitter x BN)F1 x zitter. Linkage of the zi locus to Hao-1 and Svp-1 indicated that the zi locus belongs to linkage group IV. The gene order was zi--(9.2% +/- 2.8%)--Hao-1--(27.7% +/- 6.5%)--Svp-1.

Animals↗
PubMedDate not supplied

Instability of the minisatellite sequence in the first intron of the rat renin gene and localization of the gene to chromosome 13q13 between FH and PEPC loci.

A minisatellite sequence in the first intron of the rat renin gene showed five-allelic polymorphism in 11 inbred rat strains. A new allelic variant, which was thought to be generated in the germ line, was observed in 136 animals of two sets of backcross progenies originating from parental strains with different alleles. These facts suggested that the minisatellite is genetically unstable. A linkage analysis using the backcross progenies confirmed the assignment of renin locus (REN) on linkage group (LG) X at a site between FH (fumarate hydratase) and PEPC (peptidase) loci. Fluorescence in situ hybridization allowed mapping of the renin gene on rat chromosome 13q13.

Alleles↗
PubMedDate not supplied

Effects of antiepileptic drugs on absence-like and tonic seizures in the spontaneously epileptic rat, a double mutant rat.

Electroencephalographic (EEG) studies were performed to examine the effects of several antiepileptic drugs (AEDS) on absence-like and tonic seizures in the spontaneously epileptic rat (SER: zi(zi), tm/tm,), a double mutant rat, which was obtained by mating the tremor heterozygous animals (tm/ +) with the zitter homozygous animals (zi/zi), and to determine whether the seizures in the SER correspond to human absence and tonic seizures. Spontaneous EEG was continuously recorded from the frontal cortex and hippocampus using implanted electrodes. The SER showed paroxysmal and synchronized 5-7-Hz spike-wave-like complexes in both cortical and hippocampal EEG during the absence-like state, which was characterized by immobility and staring. The animal also exhibited tonic convulsion without external stimulation concomitant with low-voltage fast waves on cortical and hippocampal EEG. In some animals, sporadic low-amplitude spikes appeared in the low-voltage fast waves during tonic convulsion. the absence-like seizures were inhibited by trimethadione (100 mg/kg intraperitoneally, i.p.) and ethosuximide 100 mg/kg i.p.), whereas the tonic convulsion was not affected by these drugs. In contrast, phenytoin (20 mg/kg i.p.) inhibited the tonic seizures without affecting the absence-like seizures. Phenobarbital (10 mg/kg i.p.) and valproate (200 mg/kg i.p.) inhibited both seizures to a similar degree. These results suggest that the SER, with both absence-like and tonic seizures, is a useful model for evaluation of AEDS.

Animals↗
PubMedDate not supplied

Long-term effects of continual intake of phenobarbital on the spontaneously epileptic rat.

Spontaneously epileptic rats (SER) are a double mutant (zi/zi, tm/tm) spontaneously exhibiting both tonic and absence-like seizures. We examined the long-term effects of continual intake of phenobarbital (PB) on SER as a method of assessing long-term evaluation of antiepileptic drugs (AEDs). Food pellets containing 0.1% PB were given ad libitum from 7 weeks of age. Plasma PB level was maintained at 30-70 micrograms/ml after age 11 weeks. Tonic seizures were inhibited markedly in rats that received PB until age 15-16 weeks, but thereafter the inhibitory effects of PB gradually decreased. An increase of body weight and prolongation of survival were also noted in SER that received PB. Cortical and hippocampal EEG of SER were recorded with chronically implanted electrodes from 11 weeks of age pre-PB and 3, 7, and 14 days post-PB intake. These animals exhibit absence-like seizures characterized by sudden appearance of 5-7-Hz spike-wave-like complexes on EEG concomitant with immobility and staring. The seizures were not affected until age 13 weeks (2 weeks after intake of PB), although tonic seizures were inhibited. SER are considered a useful model for evaluating the long-term effects of AEDs.

Animals↗