An attempt was made to isolate phages from canine staphylococci, so that phage typing of these organisms might be done. Of 150 coagulase-positive strains, 42 (28%) were proved to be lysogenic. All of them, exctpt seven, were found to carry phages of different host ranges. Of the phages detected, a few propagated to a titer of 100 RTD, and considerably many disappeared during passages for propagation. Multi-lysogenicity was demonstrated in four strains which produced two or three different phages. Based on host ranges, 16 phages were selected for typing of canine staphylococci and called "canine phages". They were divided into 7 groups according to their host ranges. Of them, five phages belonged to group I, six to group II, and one each to groups III to VII. Group II was further divided into sub-groups IIa and IIb, to which belonged three phages each.

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Pathological and etiological features were examined clinicopathologically in cases of canine dirofilarial hemoglobinuria. Dogs suffering from serious filariasis without hemoglobinuria, as well as normal healthy dogs, were used as controls. This disease is frequent in male dogs 3 years or more of age. Its incidence is high in February, March and April. Direct Coombs' test was negative in 5 cases of hemoglobinuria. Groups of serious filariasis and hemoglobinuria showed an increase in osmotic and mechanical fragility of erythrocytes, characteristic poikilocytes, and mean corpuscular constants, suggesting hemolytic anemia, liver dysfunction, increase in free cholesterol level of serum, decrease in lecithin cholesterol acyltransferase activity, and hemosiderinuria. The latency of chronic intravascular hemolysis was also confirmed in the group of serious filariasis. The hemoglobinuria group differed significantly from this group. It showed filarial embolism in the venae cavae, marked acute liver dysfunction, increase in blood glucose and BUN levels, and increase in the α/total -β ratio of serum lipoproteins. In discussing the development of pathological features of dirofilarial hemoglobinuria, attention was paid to severe liver disturbances subsequent to congestion in the liver caused by embolism of the venae cavae with worms. The increased free cholesterol content of the serum lipoproteins was presumed to be an extracorpuscular hemolytic factor, the accompanying disturbances of cholesterol exchange in the erythrocyte membrane and the possible destruction of erythrocytes in a physical collision with worms were suggested to be rather direct causes of hemolysis.

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Three littermates, two males and one female, of the Pointer breed five months of age were affected with hereditary progressive neurogenic muscular atrophy and examined clinically. Atrophy was manifested in the muscles of the four limbs and the trunk, particularly in muscles of the shoulder region. Muscular atrophy and weakness were aggravated in the course of disease. The affected dogs became completely tetraplegic. Dysphonia was also manifested. Frequent fasciculation was observed in most of the superficial muscles. The patellar reflex was diminished markedly, but always present. No cutaneous sensation was involved. No bowel and urinary disturbances were manifested. Consciousness remained to be alert and bright throughout the course of disease. Electromyography revealed widespread fibrillation potentials and positive sharp waves with polyphasic fasciculation potentials. Hematologic examination demonstrated nothing abnormal. One of the dogs died abou t 110 days after the owner noticed the initial sign of the disease, i.e., trembling in the hindliimbs during standing. The other two were subjected to necropsy.

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The ultrastructural morphology of the spheroids in the gracile nucleus and cauda equina was studied in 8 autopsied dogs 7 to 16 years of age. The spheroids were shown to originate in the myelinated, unmyelinated and terminal axons and they were tentatively classified into two types based upon the internal structures: The one consisted of intreased and combined, axoplasmic organellae, such as mitochondria, neurofilaments, microtubules and smooth-surfaced endoplasmic reticulum (sER), and the other consisted mainly of sER. The former type of spheroids showed various alterations with advancing age in the interior structurre, axolemmal demarcation and occurrence of filamentous round bodies, as well as huge vacuolation and accumulation of electron-dense materials. The findings were similar to those described in axonal dystrophy of man and animals, Hallervorden-Spatz disease, infantile neuroaxonal dystrophy and experimental vitamin E-deficient rats.

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Serum albumin in the saline extract of meat of cattle, goats, sheep, pigs, horses, dogs and cats was studied in order to use as an antigen for the serological identification of animal species of meat with anti-serum albumin antibody. Although the extract contained various components, it was proved by electrophdiesis that only serum albumin formed an immune precipitate with the antiserum. The serum albumin content in meat extract was estimated by a single radial diffusion method. It was the highest (approx. 1.95 mg/ml in mean value) in pig meat extract, the second highest (approx. 1.0-1.2 mg/ml in mean value) in cattle, goat and dog meat extracts, and the lowest (approx. 0.45-0.65 mg/ml in mean value) in sheep, horse and cat meat extracts. Although it was somewhat variable depending upon the extract examined, it was considered that every extract contained a sufficient amount of serum albumin for the serological identification with anti-serum albumin antibody.

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Morphological studies on atherosclerotic lesions were carried out on 50 cases of slaughtered swine. Intimal elevations and fibrous plaques were notable in elastic vessels. Intimal elevations revealed hemispherical protuberance of the intima macroscopically, and a tendency to occur in young swine. Histologically, the elevations represented an increase of mesenchymal elements and occasionally hyperplasia of smooth muscle cells in the intima. Large grobular cells were also observed occasionally. The fibrous plaques were observed in old swine, and revealed roughened intimal thickening macroscopically. They were prominent in elastic hyperplastic thickening and extracellular lipid accumulation in the intima histologically. In the muscular vessels, fatty streaks and fibrous plaques were notable. Fatty streaks were recognizable in the intima of abdominal aorta in younger swine and also other main arteries of rather old one, and represented slight intimal thickening macroscopically. The lesions were composed of an increase of mesenchymal elements in the intima histologically. Fibrous plaques were noted in the intima of abdominal aorta and a few arteries of rather old swine. The lesions were irregularly thickened in the intima macroscopically. Elastic hyperplastic thickening, fat deposition and calcification were histologically noted.

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To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with ¹⁵N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed an optimal protein diet (DCP 13.3%) with 2% urea (group A). ¹⁵N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of ¹⁵N-urea. The ¹⁵N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of ¹⁵N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis.

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The role of volatile fatty acids (VFA) and pH of the gastrointestinal contents in Shigella infection was investigated by using starved monkeys (Macaca fascicularis). In starved monkeys, the total VFA concentrations of fecal contents averaged 10.98±5.31 mM/dl (±S.D.) before the onset of starvation and decreased to 8.05±4.71 mM/dl after 24-hour-starvation. The starved monkeys were challenged with about 10⁹ of S. flexneri 2a by the oral route, resulting in development of pronounced clinical dysentery in 8 out of 11 monkeys (72.7%). On the contrary, the morbidity rate was only 11.8% for the group of not-starved monkeys. Before the challenge, the total VFA concentrations of fecal contents in dysenteric cases were very lower than those in non-dysenteric cases. However, the compositions of VFA were almost equal to each other in both dysenteric and non-dysenteric cases. As to 48 hr-starved monkeys, the total VFA concentrations decreased in every part of the gastrointestinal tract by 30-65%, as compared with those in not-starved monkeys. The pH values of the large intestinal tract, especially of the cecum, were higher in starved monkeys than in not-starved monkeys. These results suggest that the lowered resistance to Shigella infection in starved monkeys is largely attributable to the decrease of VFA concentrations and to the increase of pH in the large intestine, although involvement of some other unknown factors cannot be denied for complete interpretation of the lowered resistance.

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Rectal temperature was taken in 14 male and 11l female mongrel puppies born from 11 bitches which had been kept at a constant temperature of 22±2°C during pregnancy, every 5 days over a period from day 5 to day 300 after birth. It was recorded every second hour on the day. The cosinor method by Halberg was applied to analyze the measurements and to examine the development of a circadian rhythm with the growth of puppies. The results obtained are as follows. A circadian rhythm with an average amplitude of 0.1 or above developed both in male and female puppies 5 days after birth. After that, the amplitude varied with age of puppies. Three distinct periods could be recognized in the course of its development: a decreasing period from 5 to 30 days of age, an increasing period from 30 to 60 days of age in males and from 80 to 55 days in females, and a steady period after 60 days of age in males and after 55 days in females. On the other hand, The rhythm also varied in phase with the growth of puppies in the same manner ad the amplitude. Three stages could roughly be discriminated in the course of its changes: a progressive stage from 5 to 15 days of age in males and from 5 to 20 days in females, a regressive stage from 20 to 30 days in males and from 25 to 35 days in females, and a steady stage after 55 days of age in both sexes. Accordingly, it became evident that the mongrel puppies developed the distinct adult-type of circadian rhythm of rectal temperature at about 60 days of age. The cosinor graph indicated the distribution area of vectors obtained from the amplitude and acrophase of temperature rhythm. Its rejection ellipse showed a tendency to decrease in size with the advancement in age in each of the age-groups of both sexes. Furthermore, it showed a tendency to shift in a direction from the center to the upper part of the graph. Besides, rectal temperature presented a distinct rhythm, being high in the daytime and low at night. Accordingly, most of the puppies, especially the females, of each age group exhibited the adult-type rhythm. The ellipse shifted completely to the upper half of the cosinor graph at 9 months of age. This situation indicated that all the females of the age group had a complete adult-type rhythm of temperature. In male dogs 10 months of age, however, the ellipse did not yet present the adult-type rhythm. Consequently, it became evident that a distinct difference existed in the completion of the rhythm between both sexes. Furthermore, body temperature showed a gradual increase in both sexes until 40 days after birth and was stabilized thereafter.

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An experiment was carried out to clarify changes in dogs in the early stage of infection with Dirofilaria immitis. Eleven dogs free from this parasite were inoculated with mature larvae of the parasite. Clinical and pathological examinations were performed in them at regular intervals for 7 months after inoculation. The main pathological condition of dirofilariasis is located in the pulmonary artery. Changes in this artery were found to have been induced in those dogs by the parasitism of immature worm. Histopathologically, they began to be observed as endarteritis 5 months after inoculation. The endarterium was clearly coarsened and thickened one month later. The endarteritis was presumed to be one of the important factors to cause pulmonary hypertension which would lead to congestive heart failure. Furthermore, angiocardiography (ACG) revealed the presence of worms 5 months after inoculation. When changes in the intima of the pulmonary artery were observed 6 months and more after inoculation, they consisted of derangement of the dendritic structure, suspension of the blood circulation, and abnormal winding of blood vessels in the area supplied by the peripheral portion of the pulmonary artery. These results suggest that ACG may be of very high diagnostic significance in detecting pathological changes of dirofilariasis in the initial stage of infection early and exactly.

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