Although respiration in trained canines is well investigated, the process of preparing dogs has not been described in any great detail. Moreover, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (ECG) recordings are not clear. Therefore, we describe the process of selecting and training dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this training procedure was repeated 152 times. Three dogs were then selected and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with the bipolar fine needle electrodes; respiration was recorded simultaneously through a tube inserted to a tracheostomy in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movement (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9-4.1 times. The mean duration of SWS was 2.2-4.4 min and that of REMS was 3.5-4.6 min. The REMS latency was 33.9-41.8 min. Fluctuation of heart rate with respiration, termed respiratory sinus arrhythmia, was noted in the ECG. Heart beat increased with inspiration and decreased with expiration. The present study demonstrates how to select and train sleeping dogs and shows their undisturbed daytime sleep and wakefulness patterns.
A serological investigation by means of an enzyme immuno assay test for herpes B virus (cercopithecine herpesvirus 1) was performed on 961 sera of healthy nonhuman primates reared in laboratory animal facilities which belong to the Association of Laboratory Animal Facilities of the National University of Japan. An antibody prevalence of 40% (384/961) was demonstrated. The antibody titer was shown to be higher among macaques (60% of cynomolgus monkeys, 53% of rhesus monkeys, and 34% of Japanese monkeys) than among non-macaque species (21%). These data indicate that nonhuman primates reared in animal facilities may present an occupational health problem and a potential zoonotic biohazard as demonstrated in limited cases in the United States.
Abstract Cytological changes following transection of the proximal root of the trigeminal ganglion in adult rats were assessed by light and electron microscopy. Radices were transected about 3–5 mm from the ganglia and animals were killed from 1 to 60 days after the operation. Light microscopically, it was found that all Nissl granules became uniformly stained and evenly distributed throughout the cytoplasm within 3 days. Three types of cell alteration involving Nissl granules occurred within 3 to 12 days after the operation: (1) chromatolysis, (2) dark staining of the cytoplasm accompanied by an increase of Nissl granules, and (3) faint staining of the cytoplasm accompanied by dispersion of Nissl granules. Electron microscopically, the chromatolysis pattern was characterized by peripheral concentration of the granular endoplasmic reticulum (gER) and ribosomes in the cytoplasm. Neurons of the darkstaining type showed an increased number of polysomal complexes throughout the cytoplasm, whereas those of the faint‐staining type had diffusely dispersed cisternae of the gER which were shortened and bore reduced numbers of attached ribosomes. Perinuclear localization of profiles of Golgi complexes disappeared temporarily 1–3 days after the operation, but the normal perinuclear pattern appeared to return after 1 week. Enzyme histochemistry of acid phosphatase activity revealed an increase in the number of very fine reaction products in the cytoplasm up to 14 days following the operation. Cells recovered the normal pattern of Nissl staining by 48 days. Myelin figures, which are rarely observed in normal ganglia, were still observed in dense lysosomal bodies after 30 days. Nuclear size in affected neurons steadily increased up to about 2 weeks postoperation but returned to normal by 48 days.
Previous studies indicate that 1-bromopropane (1BP) has neurotoxicity and reproductive toxicity both in humans and animals. The present study investigated strain differences in susceptibility to 1BP and identified possible biological factors that determine such susceptibility. Twenty-four male mice of each of the three strains (C57BL/6J, DBA/2J, and BALB/cA) were divided into four groups of six each and exposed to 1BP at 0, 50, 110, and 250 ppm for 8 h/day for 28 days by inhalation. At the end of exposure period, the relative susceptibilities of each strain to 1BP-mediated hepatotoxicity and male reproductive toxicity were evaluated. The contributing factors to strain-dependent susceptibility were assessed by determination of hepatic CYP2E1 levels, glutathione-S-transferase (GST) activity, glutathione (GSH) status, and NAD(P)H:quinone oxidoreductase and heme oxygenase-1 mRNA levels. Liver histopathology showed significantly larger area of liver necrosis and more degenerative lobules in BALB/cA in the order of BALB/cA > C57BL/6J > DBA/2J. BALB/cA showed higher CYP2E1 protein level and lower total GSH content and GST activity in the liver than DBA/2J. These results indicate that BALB/cA mice are the most susceptible to hepatotoxicity of 1BP among the three strains tested, and that CYP2E1, GSH level/GST activity may contribute to the susceptibility to 1BP hepatotoxicity. Exposure to > or = 50 ppm of 1BP also decreased sperm count and sperm motility and increased sperms with abnormal heads in all three strains mice in a dose-dependent manner. Comparison with previous studies in rats indicates that mice are far more susceptible than rats to 1BP regarding hepatotoxicity and reproductive toxicity.
Previously, Sugiyama (1967) described the occurrence in the human thyroid gland of the parafollicular cells which are completely identical in histology with those of mammals.
