[Facilities, equipment, and biohazards]

The high quality of laboratory animals, the precise and proper humane treatment of animals and the well-controlled environments are the three essential factors for animal experimentation. The defect or disturbance of any of these factors might be a common causation of so-called biohazards, such as a sporadic occurrence of epidemic hemorrhagic fever in Japan. The caging or housing systems, which is the most essential part for proper functioning of animal facilities, were described. In the uninfected animal areas, the air-conditioning system was designed to isolate each room and separate it from unrestricted space in the facility. In the areas for the experimentally infected animals, it was designed to protect the infection among the experimental animals or investigators. The systems of safety handling equipments, containments of infectious agents, and disposal of contaminant materials were discussed. Finally, it was emphasized that the researchers have to be for the protection against the biohazards throughout animal experimentation.

Chronic Niemann-Pick disease with sphingomyelinase deficiency in two brothers with mental retardation

Clinical, biochemical, and electron microscopic studies are presented in two brothers with Niemann-Pick disease. The clinical features include hepatosplenomegaly and mental retardation without any other neurological signs. Roentgenograms of the chest showed bilateral diffuse reticular infiltration. The amounts of sphingomyelin and cholesterol in liver were increased, and sphingomyelinase activities in both liver and skin fibroblasts were markedly reduced in Case 1. Numerous foam cells and myelin figures were observed in the liver, kidneys, bone marrow, and lymph nodes on electron microscopical examination. These cases were regarded as a variant of Niemann-Pick disease from our investigations as they have mental retardation as an exceptional symptom when they are diagnosed as type B.

Demonstration of two different vitamin D-dependent calcium-binding proteins in rat intestinal mucosa

The characteristics and location of rat intestinal proteins with calcium binding properties were reexamined using both a 45Ca-equilibrated Sephadex G-100 column and the chelex 100 method in the assay of 45Ca binding activity. The rat intestinal mucosa was found to have three different proteins with calcium binding properties. Two of these proteins were found to be vitamin D-dependent and were examined in detail. The larger vitamin D-dependent protein, found predominantly in the jejunum and ileum, had a molecular weight of 27,000 and demonstrated low affinity for calcium; the detection of this protein by the chelex 100 assay was very difficult. The smaller vitamin D-dependent protein, which was associated mainly with duodenum and jejunum, had a molecular weight of 12,500, and demonstrated a high affinity for calcium.