Deposition of iron dextran particles in the fetoplacental system was investigated by light and electron microscopy after intravenous injection into pregnant mice on days 18-19 of gestation. Thirty minutes after injection, the labyrinth trophoblast cells were strongly positive for iron whereas the fetal capillary endothelium was weakly stained. Electron microscopy revealed the transfer of iron dextran particles to the intercellular space between the first and second layers of trophoblasts, as well as within the vacuoles of the second layer trophoblasts. Transport through the second layer trophoblasts, however, was not evidenced, suggesting that the trophoblast layer may constitute a significant barrier. Three hours after injection, heavy iron reaction was observed in Reichert's membrane, trophoblast cells lined with this membrane, and visceral yolk sac. Electron microscopic examination of parietal yolk sac revealed the aggregation of iron dextran particles in the trophoblast cells with little penetration into the Reichert's membrane and parietal endoderm, suggesting that the Reichert's membrane and adhering trophoblast cells may be a significant barrier for selective transport of particulate materials in the yolk sac placenta.

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Automatic blood cell analyzer “MICROX” was examined for possible applicability to the differential count of white blood cell in the monkey and in the dog. Spun blood smear slides prepared from 42 monkeys and 60 dogs were stained with Wright's dye and totals of 4971 white blood cells of the monkey and 7189 cells of the dog were counted, respectively. The identification rate of MICROX was checked by the cell by cell counting method on a monitor TV of the instrument. Analysis of the data was made to examine correlationship between the results of MICROX and of optical microscopy on the same slides. 1) Identification rates and misclassification rates were 97.0% and 3.0% respectively in monkeys and 96.4% and 3.6% in dogs. 2) A high degree of correlation was observed between the results by MICROX and by optical microscopy in respect of segmented neutrophils and lymphocytes. 3) There were an average of 15.5 cells counted as unknown cells in monkey blood and 16.5 in dog blood per 100 cells, respectively. Of the unknown cells about 40 to 50% were closely disposed leukocytes within the same counting squares and almost all of atypical lymphocytes and erythroblasts were also counted as unknown cells on the analyzer. The data support the feasibility of the use of MICROX for the differential count of white blood cells of normal monkeys and dogs.

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Histopathological findings of pulmonary alveolar proteinosis occurring spontaneously in aged KK mice (72 weeks of age) were described. The lung tissues examined were obtained from the mice used for a one-year toxicity study of some oral hypoglycemic drugs, but there was no relationship between the incidence of the disease and the drug treatment. The disease occurred in 67 of 319 males (21.0%) and 124 of 284 females (43.7%) . The gross lesions of the lungs were solitary or multiple nodules. Microscopically, the lesions developed in the peribronchial areas and were well-circumscribed. The initial lesions consisted of the aggregation of foamy cells in the alveoli. In the advanced lesions, amorphous substance resulting from destructed foamy cells and proteinous material accumulated in the alveoli. In the more advanced lesions, neutrophils and nuclear fragments were contained in the proteinous material and some of the alveolar walls were thickened with cell infiltration, fibrosis and so-called epithelialization. The etiology of the present condition was unknown.

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Resistance of mice with active and maternally passive immunity to Sendai virus infection was investigated. Mice with active immunization were convalescent ones from intranasal infection with 10³ TCID₅₀ of the virus [CT], ones immunized with 4 weekly intranasal injections of about 4×10³ hemagglutinating units (HAU) of formalin-inactivated virus (FV) [IN], or ones immunized with 4 weekly intraperitoneal injections of about 2×10³ HAU of FV [IP] . The serum neutralizing (NT) antibody titers ranged 1: 10 to 1: 20 in CT and IN, and 1: 20 to 1: 40 in IP at 4 weeks after initial immunization. NT antibody in the lung lavage was detected only in IP in 3/5. After intranasal challenge infection with 10⁶ TCID₅₀ of the virus, little or no gross lung lesion, no virus recovery and no body weight loss were observed throughout experiment, in these 3 immunized groups, whereas, control mice showed lung lesions in 4/5 (7 days), virus recovery in 4/5 at 3 days and in 1/5 at 7 days post-challenge, and body weight loss. In additional histological study, bronchiolar epithelial methaplasia and alveolar septal thickening, which were characteristic findings in non-immunized infected mice, were not observed in mice immunized with 2 biweekly injection of about 250 HA of FV and then challenged. Maternal immunity was investigated in offsprings from convalescent dams infected with 10³ TCID₅₀ at mating [mCT] and from dams immunized intraperitoneally with 4×10³ HAU of FV at 0, 1 and 2 weeks after mating and, 1 and 2 weeks after parturition [mIP] . Serum NT antibody was not detected in mCT, but the titers ranging 1: 20 to 1: 40 were detected in mIP. After intranasal challenge of mCT, mIP and offsprings from non-immune mice with 10³ TCID₅₀ of the virus, virus recovery on day 3 was 2/4, 1/4 and 3/3, and incidence of total lung lesions on day 7 and 12 was 11/21, 2/13 and 16/16, respectively. Body weight gain was suppressed slightly in the immune groups but markedly in the non-immune control.

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Water intake (drinking water and water from food) and urinary output in rhesus (Macaca mulatta) and cynomolgus monkey (M. fascicularis) watered ad libitum in individual cage were examined with 52 animals. The animal room was maintained at 25±2°C and 55±10% with relative humidity, being lit at 12 hours interval. Water intake was found in wide variation between individuals, and about 20% of the monkeys were recognized as polydipsia without another abnormal behavior. No significant variation was found between daily water intake, but periodical (or seasonal) variation was observed in polydipsic monkey. Urinary output changed accordingly with water intake. Rate of the urinary output to the water intake was 76% in male rhesus, 59% in male Cynomolgus and 49% in female Cynomolgus. The rate was higher in the polydipsia than in the normal monkey. Diurnal patterns of water drinking and urinary output indicated that the monkeys were mostly active during the hours of lighting. Some effects of experimental procedure were observed on drinking and voiding in Cynomolgus monkeys while no effect on rhesus monkeys. Prandial drinking was observed in monkeys as was reported on other laboratory animals such as rats.

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Some field voles with a white coat color were found in the breeding process in the laboratory, originated from a wild population captured in the riverside of the Arakawa in Okegawa, Saitama prefecture in Japan. They had been raised in a room and fed with pelleted feed for herbivore. An attempt was made to analyze their breeding records and mode of inheritance for the white coat color. As a result, the average litter size was 3.80±1.52, and the age of the first birth was 121±46.8 in days. This shows that most of the characters of the white voles are not different from those of the agouti ones. From the results of the mating tests, it might be concluded that an autosomal recessive gene was responsible for the appearance of the white coat color.

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An experiment was conducted with 236 mice (3-9 weeks of age) to determine the bias in taking soft-X-ray photograph, and systematic and random errors of the values measured with a picture analyzer. Sites measured are length of scapula (SCAL), humerus (HUML), ulna (ULNL), coxae (COXL), femur (FEML), tibia (TIBL), thoracic vertebrae (VTL), lumbar vertebrae (VLL) and sacral vertebrae (VSL), and width of scapula (SCAW) and coxae (COXW) . Systematic bias peculiar to the procedure was found in the values of bones measured. The X-ray photograph caused the downward bias to the length of sacral vertebrae alone, but did not to others. The standard errors of measurements (squared root of error variance) with picture analyzer ranged between 0.12 and 0.24 mm and had no apparent relationship to the size of bone.

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Hematocrit value and total blood volume of both the germf ree and conventional mice of the strains C3H/He and IVCS were examined at the age of 70 to 100 days. On the value and volume, no significant difference was observed between germf ree and conventional mice.

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A total of 21 apparently healthy experimental ferrets, 8 males and 13 females, comprizing 1, 2 and 3 year-old animals were examined for Mycoplasmatales. Mycoplasmas were isolated from 17 samples of 21 oral cavities (81.0%), and from 2 of 21 nasal cavities (9.5%), but not from the prepuce or vagina of the animals. Neither ureaplasma nor acholeplasma was demonstrated in any of the locations of the ferrets examined. These mycoplasma strains proved to metabolize glucose but not arginine and urea. The growth inhibition test revealed that all the strains had similar antigenicity but were not related antigenically to any reference strains from dogs, cats, sheep, cattle, mice, raccoon dogs and a Japanese badger. They are the first mycoplasmas to be isolated from ferrets.

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