Tamotsu Koyama

Effects of Malnutrition on Development of Experimental Pressure Sores

Using food‐deprived rabbits we investigated the effects of nutritional deficiency on the development of pressure sores. The body weight of these animals was decreased significantly from normal. Organ weights of liver, heart, spleen, kidney, and testis were significantly decreased from normal as well. Protein deficiency in these animals was indicated by serum tests, as well as by histologic features of liver and testis and ultrastructural findings on fibroblasts. We produced lesions in malnourished as well as normal rabbits by exposing their skin to a balloon‐produced compressive force of 120 ± 10 mmHg for 4 hours. Biopsies were taken 1, 2, and 3 days after the pressure application. Histologic findings at each time were as follows: At day one, the degree of ischemic skin destruction in the malnourished animals was more severe than that in the normal ones, and thrombi were occasionally seen in the malnourished cases. At day two, proliferation of fibroblasts and macrophage infiltration were evidenced in the normal animals, whereas signs of collagen fiber degeneration as well as microthrombi were seen in the malnourished ones. At three days, epidermal cells covered the lesions in the case of normal animals; however, massive necrosis of the epidermis was still recognized in the malnourished rabbits. Thus, the healing process of pressure sores was strongly suppressed in the malnourished animals. This suppression was attributed to the reduction in fibroblast proliferation, capillary formation, macrophage infiltration, and also to the low level of epidermal cell proliferation.

Parathyroid Morphology in Rats After Administration of Active Vitamin D3

The morphology of the parathyroid gland was examined in rats treated for one month with an active vitamin D3, 1α‐hydroxyvitamin D3. On continuous adiministration of 12.5 μg/kg/day of 1α‐hydroxyvitamin D3, the first histological change of the parathyroid gland, seen on day 10, was atrophy of the chief cells with marked accumulation of prosecretory granules. Replacement of the parenchyma by small or large cysts was evident on days 20 and 30. The remaining portion of the parathyroid parenchyma showed various histological changes: widened intercellular spaces intermingled with many cytoplasmic processes, shrinkage of the cytoplasm of the chief cells, and the presence of a few ghost cells in cysts. The appearance of cysts may be caused by suppression of parathyroid hormone secretion and is a characteristic lesion in hypervitaminosis in rats induced by treatment with active vitamin D3.

The preclinical safety evaluation of human monoclonal antibody against cytomegalovirus

The human monoclonal antibody against cytomegalovirus (Mab C23) was examined pharmacokinetically and toxicologically as part of the preclinical studies prior to approval for human use. Rats given repeated intravenous administrations of Mab C23 produced no antibodies against Mab C23 and maintained a blood Mab C23 level in a dose-dependent manner. However, pregnant rabbits produced antibodies against Mab C23. The half-life of Mab C23 in plasma was 15.9 days in rats, which was similar to that of normal human serum gamma-globulin (NHSG). Neither behavioral effects nor circulatory disturbance was found in mice, rats, and dogs even after a single intravenous injection of 100 or 200 mg/kg, which corresponds to 50 or 100 times the intended clinical dosage. The repeated doses of 2, 10, or 20 mg/kg of Mab C23 on six occasions with 1- or 2-week intervals elicited a transient decrease in leukocyte counts in rats given 10 or 20 mg/kg, but no adverse effects in cynomolgus monkeys. Mab C23 did not cause any reproductive or developmental toxicity when administered to rats and rabbits at dose levels of 20 mg/kg or less. However, pregnant animals showed lower plasma levels of Mab C23 than non-pregnant animals. The chromosomal aberration test disclosed no clastogenicity in human lymphocytes. An immunostaining for Mab C23 revealed no localizations in several tissues of cynomolgus monkeys given intravenous doses of Mab C23.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of a Human Monoclonal Antibody against Cytomegalovirus with the Aim of a Passive Immunotherapy

A human monoclonal antibody (Mab) against cytomegalovirus (CMV) has been studied with the aim of applying it as a passive immunotherapeutic agent for CMV infection. The monoclonal antibody, designated Mab C23, was produced by a hybridoma generated by cell fusion of a human lymphocyte and a mouse myeloma cell. This IgG1 Mab was highly purified by four kinds of column chromatography and compared with native human IgG1. No difference in the constant region was detected by either protein nuclear magnetic resonance or immunoreactivity with goat antibodies against human IgG.

Lipidosis of the dorsal root ganglia in rats treated with an almitrine metabolite

Toxic effects of a detriazinyl metabolite of almitrine (DTMA) were evaluated in rats and on cultured rat macrophages. In rats daily treated with DTMA for 16 weeks, spastic gaits with heel-lifting appeared, and lamellated and/or crystalloid bodies formed in sensory neurons, satellite cells, Schwann cells, and vascular endothelial cells of the dorsal root ganglia. The lysosomal lamellated bodies, which were not induced by almitrine, were produced also in cultured rat macrophages exposed to over 1 ξ 10−5 M DTMA.

Disorders of bone metabolism caused by small bowel resection in rats

SummaryDisorders of bone metabolism caused by resection of three quarters of the small bowel in rats were investigated biochemically and histomorphologically. Metabolic bone disorders developing 90 days after in 75%-distal-small-bowel resected rats were characterized by reduction in ash content of the femur and by the disappearance of the trabecular bone in tibial metaphysis. Biochemical studies showed significant decrease in serum Ca and 1,25-dihydroxyvitamin D concentrations in 75% distal small bowel resected rats. These data suggest that 75% distal small bowel resection impairs intestinal absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic disorder in rats. On the other hand, 75% proximal small bowel resection causes no obvious metabolic bone disorders in rats, possibly because of the adaptation by the remaining part of the intestine.

Toxicological aspects of feprazone, a new nonsteroidal anti-inflammatory drug

Abstract The subacute and chronic toxicities of oral feprazone were studied in rats and beagle dogs. Administration of more than 150 mg/kg/day of feprazone to rats for 1 month induced retardation of growth and liver enlargement. In addition, treatment with 600 mg/kg/day of feprazone caused death, gastrointestinal ulcers, decreased hemoglobin concentration, and leucocytosis. Treatment of rats with 540 mg/kg/day of feprazone for 6 months had similar effects to those described above except that it did not cause death or gastrointestinal ulcers. Toxic nephropathy, nontoxic goiter, hepatomegaly, and increase of ovarian weight were observed in rats given more than 60 or 180 mg/kg/day of feprazone for 6 months. Injection of 1080 mg/kg/day of feprazone into dogs, caused one of six animals to become moribund on Day 18 and one to die on Day 7. The dogs surviving after administration of 360 and 1080 mg/kg/day of feprazone for 1 month showed anemia, leucocytosis, and elevations of phenolsulfonphthalein retention and serum alkaline phosphatase (ALP) activity. Similar effects were observed in dogs surviving after treatment with 150 or 375 mg/kg/day of feprazone for 12 months; in addition, increased ALP activity was observed even at a dose of 60 mg/kg/day. Liver enlargement was observed in dogs treated with all doses of feprazone for 1 or 12 months, and cytoplasmic inclusion bodies were observed in liver cells of dogs given more than 120 mg/kg/day of feprazone for 1 month.

In‐vivo and in‐vitro hepatoprotective effect of 4‐thia‐prostaglandin E1 and 7‐fluoroprostacyclin in rats

Abstract— 4‐Thia‐prostaglandin E1 and to a lesser extent 7‐fluoroprostacyclin showed a potent protective effect against carbon tetrachloride‐induced liver injury in‐vivo and in‐vitro in rat.

Effect of 1α-hydroxyvitamin D3 on bone metabolic disorders in gastrectomized rats

The effect of 1α-hydroxyvitamin D3 (1α(OH)D3) on the metabolic bone disorders developed in gastrectomized rats were investigated biochemically and histomorphologically. 1α(OH)D3 was suspended in 0.2 % Triton-X-100 aqueous solution after dissolving in a very small amount of ethanol, was given orally to the rats for 10 weeks. The sham operated animals and the gastrectomy control animals received the vehicle alone. Gastrectomy was followed by the development of the metabolic bone disorders after 10 weeks of observation. This was characterized by reduction in ash content of the femur and histologically by a disappearance of the trabecular bone in tibial metaphysis. Decrease Ca absorption from the intestines was demonstrated by a radiotracer technique. Biochemical studies showed significant decreases in serum 25(OH)D concentration in gastrectomized rats. These findings suggest that gastrectomy partially impairs intestinal absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic disorders in rats. The administration of 1α(OH)D3 increased dose-dependently serum calcium and Ca absorption from the intestine and prevented the development of bone metabolic disorders histomorphologically.

Bone metabolic disorders caused by small bowel resection, and the influence of 1α-hydroxyvitamin D3 on the rats

Metabolic bone disorders caused by resection of the distal three quarters of the small bowel and the effects of 1α-hydroxyvitamin D3 (1α(OH)D3) on the rats were investigated biochemically and histomorphologically. 1α(OH)D3 was administered orally to the rats for 13 weeks. A group of “ sham operation” animals and the 75%-distal-small-bowel-resected control animals received only the vehicle. Bone changes developed 13 weeks after the partial bowel resection. The disorder was characterized by reductions in ash content of the femur and by the disappearance of the trabecular bone in tibial metaphysis.Decreased Ca absorption from the intestines was demonstrated by a radiotracer technique, and biochemical studies showed significant decreases in serum Ca and 1,25(OH)2D concentrations in the bowel-resected rats.These findings suggest that 75% distal small bowel resection impairs intestinal absorption of calcium and results in a negative calcium balance, which may contribute to the development of bone metabolic disorder in rats. This disorder was demonstrated as high bone turnover via urinalysis and by a radiotracer technique.Administration of 1α(OH)D3 increased dose-dependent Ca absorption from the intestine and the serum Ca, normalized the bone turnover rate and prevented the development of bone metabolic disorder.