We have investigated the development of the Harderian glands of Japanese white rabbits from birth to 4 months of age. Although two types of secretory cells comprise the glandular epithelium of the pink and white lobes in fully developed glands, the time of neonatal appearance is different between the two. Cells consisting of the pink lobe first appear on the third day of life, while cells of the white appear around seventh day of life. The ultrastructure of the Harderian glands from 1-week-old rabbits resembles that of adult animals. The gland can be divided into three parts on the basis of their epithelial cell composition at the electron microscopic level. The respective parts are composed of: (1) one type of cells with large vacuoles (pink lobe), (2) one type of cells with small vacuoles (white lobe), and (3) two types of cells with large and small vacuoles (pink-white mixed portion). The relative number of plasma cells per 1 mm2 is low in both pink and white lobes during early postnatal life. However, in adult animals, the white lobe has a larger number of plasma cells than the pink lobe. These results suggest the possibility that the white lobe participates in the immune system more than does the pink.

Animals↗

PubMedDate not supplied

Endocrinological and biophysical responses to further reduction in oxygenation following sustained hypoxemia in fetal goats.

OBJECTIVE: The purpose of this study was to determine fetal endocrinological and biophysical responses to the further reduction in oxygenation following prolonged nonacidemic hypoxemia in fetal goats. METHODS: Seven further hypoxic experiments were performed after prolonged (24-h) nonacidemic hypoxemia, caused by an infusion of nitrogen into the maternal trachea and by reducing uterine arterial blood flow in four chronically instrumented goat fetuses at 123-131 days' gestation. We measured arginine vasopressin, adrenocorticotropic hormone, cortisol, and catecholamines as endocrinological parameters. Fetal heart rate, fetal blood pressure, and fetal breathing movement were observed as biophysical parameters. RESULTS: Fetal arterial pO2 was significantly decreased from 27.0 +/- 1.2 mmHg (control) to 18.0 +/- 0.7 mmHg and 11.3 +/- 1.3 mmHg at the end of the prolonged hypoxemia and the further hypoxia, respectively. The further hypoxia induced reductions in fetal heart rate, increases in fetal blood pressure, and a series of gasping. Arginine vasopressin and catecholamines were elevated significantly by the further hypoxia. Although adrenocorticotropic hormone and cortisol were increasingly elevated, they did not reach a significant level. CONCLUSIONS: Some specific fetal responses-excessive elevations of fetal catecholamines, arginine vasopressin, accompanied with fetal gasping-were observed during further severe hypoxia.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Does the substitution of a resident for a flight nurse alter scene time?

The purpose of this study was to compare the performance of a nurse resident crew (N/R) to that of the usual nurse/nurse (N/N) crew in a helicopter transport service using scene time as a measure of overall teamwork. It was designed as a retrospective case control study carried out by a university-based helicopter emergency transport service. Emergency Medicine second-year residents who volunteered to be assigned to the helicopter transport service for 1 month rotations flew with an experienced flight nurse. This nurse/resident (N/R) team was compared to the usual nurse/nurse (N/N) team in scene trauma flights. The average ground time for the N/N crew (10.5 minutes, n = 43) was not significantly different from that of the N/R crew (10.3 minutes, n = 43). This study suggests that an emergency medicine resident can be incorporated into a flight crew without adversely affecting scene time.

Adolescent↗

PubMedDate not supplied

Male urinary protein-1 (MUP-1) in the rat: Mup-1 assigned to linkage group II.

A polymorphism was found in the electrophoretic mobilities of male-specific rat urinary proteins. The proteins (MUP-1) are inherited as a single autosomal trait. The Mup-1 locus possesses two codominant alleles Mup-1a (fast-migrating type) and Mup-1b (slowing migrating type). Mup-1 is closely linked to b (brown coat color), with a recombination frequency of 7.7 +/- 4.3 percent. The similarity to the linkage between Mup-1 and b in mice and rats is discussed.

Animals↗

PubMedDate not supplied

Male urinary protein-1 (Mup-1) expression in the female rat.

The male urinary protein-1 (Mup-1) gene was detected in female rats on an acrylamide gel electrophorogram by concentrating the urine 100-150 times. The expression of Mup-1 in females showed polymorphisms that were confirmed to be controlled by the same alleles observed at the male Mup-1 locus. Moreover, the linkage between Mup-1 and b in females closely coincided with the value found in males. The combined estimate of the recombination frequency was calculated as 8.6 +/- 2.9 (9/105). Using anti-male MUP-1A serum, the Mup-1 gene was clearly detected on agarose gel electrophorograms of not only intact male but also intact female urine.

Animals↗

PubMedDate not supplied

Evidence for separate gene loci (Es-1 and Es-Si) controlling serum esterases in rats.

The presence or absence of the Es-Si esterase (female specific sex-influenced esterase) in rat sera was reexamined by the zymogram technique using agarosegel electrophoresis. It was found that female rat sera of the BN/Kyo strain, which has been typed as the Es-Si esterase negative, display an esterase migrating between the Es-1A esterase and the Es-2C esterase. Using a specific alloantibody to the esterase, it was shown that this esterase is identical to the Es-Si esterase. Thus, BN rats are the first described inbred rats possessing the Es-Si esterase, as well as the Es-1A esterase. Mating experiments between BN rats and SHR rats confirmed a previous demonstration that the presence or absence of the Es-Si esterase is controlled by a single gene locus closely linked to the Es-2 locus where the Es-1 locus also is linked. A further survey with 39 strains by the present methods revealed that besides two sublines of the BN strain, E3/Han, LOU/Max and PVG/Max strains also possess both the ES-1A esterase and the Es-Si esterase. The results indicate that these esterases are controlled by separate gene loci.

Animals↗

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↗