Bacteriological survey to evaluate the quality as a food was carried out on raw oysters harve-sted in the two representative localities of oyster. production in Japan. The localities of oyster production selected in this study was Hiroshima and Miyagi-Iwate, Tohoku district. The former has warmer climate than the latter throughout a year. Sampling of the oysters was done at the time when the temperature of seawater was almost equal between the two localities. Samples of the oyster were collected from the Tsukiji Central Market in Tokyo and transported to the Department of Hygiene and Microbiology, National Institute of Hygienic Sciences being kept in ice. Assay of both of aerobic and anaerobic bacteria was made with the new method to test microbiological flora of foods developed by the author. A total of 29 from Hiroshima and of 18 samples from Tohoku was examined and 2, 576 strains of bacteria were isolated and identified. Bacterial strains, which represented the difference between the two geographical areas, were subjected to the ligated ileal loops test using the mouse and rabbit, in order to investigate the enteropathogenicity.
Results obtained are summerized as follows :
1) Viable cell counts of the Hiroshima oyster and the Tohoku oyster at 35°C showed 10²-10⁶ and 10²-10⁵ cells per gram, respectively.
2) Microbial flora of the Hiroshima oyster comprised Pseudomonas III/IV-NH, Pseudomonas II, Pseudomonas III/IV-H, Vibrio alginolyticus Vibrio spp., Flavobacterium spp., Enterobacter cloacae, Enterobacter aerogenes, Streptococcus faecium, Lactobacillus spp., Bacillus spp., and Clostridium perfringens. Non halophilic Pseudomonas III/IV-NH was predominant and Aeromonas hydrophila was detected only from the Hiroshima oyster. A. hydrophila subspecies hydrophila biotype 1 was predominant among the genus Aeromonas isolates.
3) Microbial flora of the Tohoku oyster comprised Pseudomonas III/IV-H, V. alginolyticus, Vibrio spp., Moraxella spp., and Acinetobacter spp. Halophilic Pseudomonas III/IV-H was predominant.
4) Live cell and cell-free culture supernatants from 15 strains of A. hydrophila isolated from the Hiroshima oyster caused remarkable accumulation of the fluid in ligated ileal loops in both of the adult rabbit (2-3 months old) and the mouse (4-5 weeks old). In addition, the live cell and the supernates were also injected into the stomachs of suckling mouse (3-4 days old) and the fluid accumulation in the intestine was measured by weighing after 3 h. The minimum viable cell number of bacteria which caused the fluid accumulation in the ileal loops of rabbit was 103 in 1 ml of the inoculum.
As positive results were obtained in this enterotoxigenicity test with the organism, it should not be neglected that A. hydrophila may be one of the etiological agents for the oyster poisoning in Japan.

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Studies of El Tor cholera Vibrio have been studied by a great many workers in the past.
Unfortunately, however, the biological study of El Tor cholera Vibrio is still meager. And the growth and survival of El Tor cholera Vibrio in foodstuffs is a important problem of infection. Therefore, several experiments were conducted. The first experiment was made with the object of clarifying the vital time of El Tor cholera Vibrio in cola, alkali ion drink, milk, coffee, peptone solution and soy sauce. The second was made, increase or decrease of the number of El Tor cholera sticking to raw fish and raw meat in settled temperature. The third, whether El Tor cholera Vibrio was accumulated in short-necked clams in artificial sea water which was contamined with El Tor cholera Vibrio.
Factors influencing the survival of El Tor cholera Vibrio were studied. Results obtained were followings.
1) El Tor cholera Vibrio became extinct within 5 min in soy sauce of a high salt concentration and within 15 min in cola and alkali ion drinks of high acidity. But they did not extinct up to 60 min in milk, coffee and peptone solution.
2) El Tor cholera Vibrio sticking to raw fish or raw meat survived longer at 8°C than at 16°C or 24°C. The number of surviving El Tor cholera Vibrio increased temporally but decreased lator. The number of its increase was positively corelated with the degree of environmental temperature.
In addition, when short-necked clams were placed in artificial sea water which had been contaminated with El Tor cholera Vibrio, it was found that organisms were accumulated and survived within short-necked clams.

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The in vivo effects of prostaglandins on the immediate type allergic reactions were investigated on the capillary permeability in the rat. The following result were obtained.
1) The increased capillary permeability provoked in the skin by the intravenous injection (i. v. inj.) of chemical mediators (H, 5-HT, BK) was significantly suppressed by the subcutaneous injection (s.c. inj.) of PGE₁ or PGE₂, whereas it was enhanced by the s.c. inj. of PGF_2α.
2) The increase on capillary permeability provoked in the skin by s.c. inj. of 5-HT was inhibited by 95% when PGE₁ was administered 10 min before the challenging injection by 89% when administered 60 min before. But when administered 120 min or more before, the inhibitory effect of PGE₁ was significantly reduced.
3) Forty-eight h passive cutaneous anaphylaxis (48 h PCA) was significantly suppressed by the s.c. inj. of PGE₁ and PGE₂.
4) Reversed PCA using sheep anti-rat IgE serum was significantly suppressed by the s.c. inj. of PGE₁, but was enhanced by s.c. inj. of PGF_2α.
5) Using the modified method of the air bleb, the effects by s.c. administration of PGE₁ were examined on the leakage of the dye exudated into air bleb after the provoking injection of sheep anti-rat IgE serum into the bleb. Results obtained indicated that it was remarkably suppressed by the administration of anti-rat IgE serum. However, the more prolonged was the time of PGE₁ administration after the challenging injection, the more reduced was the inhibiting effect.
6) From the microscopic examination in the extention samples of the bleb's wall, provoked by compound 48/80 immediately before i. v. inj. of colloidal carbon in the tail vein, the administration of PGE₁ remarkably suppressed vasoexpansion and the leakage of carbon from venules.

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Strains of influenza virus were isolated from the epidemics in Japan over a period of 1979 to 1982. Virologically, they were compared with those isolated from materials collected from Southeast Asian region (The Philippines and Thailand) during 1980 to 1981.
The following results were obtained.
1) A total of 811 samples were collected from the Philippines and Thailand over a period from May, 1980, to August, 1981. The virus was isolated from 74 of them (9.1%).
2) When the 74 strains were identified, the Hongkong A type was predominant (42 strains, 56.8%) and followed by the Russian A type (21 strains, 28.4%) and the B type (11 strains, 14.9%).
3) The virus was isolated from materials collected in this region in every season, though there was a seasonal difference in the frequency of isolation.
4) It was clarified that some strains isolated from epidemics in Japan had appeared in Southeast (SE) Asia six or less months prior to Japan.
5) It was elucidated that new variant strains circulated together with some old variants in SE Asia within the category of the antigenic drift.
These results indicate the necessity to advance the further detailed investigation to understand the significance of the coexistence of new and old variant strains in Southeast Asian region.

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Labelling index (LI) of the canine gastric cancer induced by N-ethyl-N'-nitro-N-nitrosogua-nidine (ENNG) was investigated in vivo by pulse injection of [methyl-³H] thymidine intravenously. LIs of cancerous lesions were lower than those of generative cell zones of the gastric mucosa in the control dog. There were variations in LIs among each lesion of the same histological type of carcinoma and also among the different areas of a single carcinoma. The mean value of LIs of well differentiated type of adenocarcinoma in the mucosa was higher than that of the poorly differentiated type. Especially, signet-ring cell carcinoma showed significantly lower LI than those of other types of adenocarcinoma (t-test, p<0.05). In the well differentiated adenocarcinoma the value of LI (y) decreased strikingly with the increase in the diameter (x) of the carcinoma with the regression curve y=6.645/x^0.3766(p <0.05). On the contrary, the value of LI(y) increased proportionally with the increase in the diameter(x) of carcinoma in the poorly differentiated type of adenocarcinoma with the straight line y=0.213 x+0.95 (r=0.535, p<0.05).

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There have been many reports on the application of epidural venography in patients with lumbar intervertebral disc herniations. Epidural venography has been applied to patients with low back pain for screening purposes or employed when myelographic findings were equivocal.
During the period of 1972 to 1979, the author venographically investigated 57 cases with lumbar intervertebral disc herniations in which myelography was also carried out. It was found that 21 out of 57 cases (37%) showed caudal flow defects or cranial flow defects.
In the case of flow defects, epidural venography does not permit to determine the precise level of involvement in the intervertebral space, unless the caudal or cranial anterior internal venous plexus is contrasted through its presacral vein. Catheterization of the presacral vein is not always easy. However, the conventional catheter was remodelled according, to the anatomical investigations of the presacral veins in 28 cadavers (56 limbs), in which the branches of the presacral veins were classified into five types. As a result, catheterization of the presacral vein and the ascending, lumbar vein was carried out without much difficulty.
From 1979 to 1982, venography was applied to an additional 30 cases with lumbar intervertebral disc harniations admitted into the hospital for operations. At surgery, it was confirmed that herniated discs occurred exactly at the level, as indicated by the venography. In 6 cases showing caudal flow defects, caudal epidural venous plexus was contrasted by its catheterization of the presacral veins. In 2 cases showing cranial flow defects, the cranial venous plexus was contrasted by shifting the height of catheter tip toward the ascending lumbar veins on the left side.
In 29 out of 30 cases, venographic findings agreed with operative findings.

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1) EEG spikes were studied in the hippocampus of normal and septum-lesioned rabbits in acute experiments., They were anesthetized with Nembutal and immobilized with. D-tubocurarine.
2) EEG spikes, recorded with concentric electrodes occurred spontaneously in normal as well as septum-lesioned rabbits. They disappeared after the mid-pontine pretrigeminal transection in both preparations.
3) EEG spikes were recorded also with the microelectrode. This indicates that EEG spike generation was not subsequent to injury discharge due to gross electrode introduction.
4) The intracellular 'counterpart of the EEG spike was a hyperpolarization of the pyramidal cell, which consisted. of Cl-dependent and Cl-non-dependent components. Their magnitudes were much, , smaller, than those of the interictal spike.

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Clinico-pathological and angio-pathological studies have been performed in 53 autopsy cases of the renal cortical necrosis, fresh renal infarcts and renal glomerular thrombosis. A detailed investigation has been carried out on the causative factors of necrotic lesions and thrombotic lesions which are resulted from circulatory derangement, and the following results are obtained.
1) Renal cortical necrosis in 12 cases out of 53 cases are encountered and among them two cases are classified in supra-super acute variety. Extensive and bilateral occurrence of the lesions are of note-worthy. The entity is frequently observed in aged group and underlying. diseases, such as malignant neoplasms, leukemia and infectious infections are also noted.
2) Fresh renal infarcts are observed in 18 cases out of 53 cases. The entity is also frequ-ently seen in aged group, suffering from heart, brain and aortic diseases from cornary, cerebral and aortic arteriosclerosis. The lesions are also tend to be multi-focal and bilateral.
3) The renal gromerular thrombosis is seen in 23 cases out of 53 cases and appear to be increasing in frequency recently. The entity is frequently observed in cases of malignant neoplasms, and septicemia. It is of interesting to note that the occurrence of the thrombosis is frequently seen in mucin-producing adenocarcinoma in malignant epithelial tumors. The abnormality of the coagulation-fibrinolysis system is justified as most important contributory factor in causation of the fibrin thrombosis. In far extensive cases of thrombosis, the secondary ischemic changes are frequently observed in renal glomeruli, however, the author justifies that the latter change is not closely related with the causation of the renal infarction.
4) The clinical investigation reveals the correlative findings of azotemia, or positive urynalysis with the degree and extent of the necrotic or thrombotic lesions. Severe anemia or visceral hemorrhage which is commonly seen in the terminal stage and eventual lowering of blood pressure may be justified as main causative factor of these disease conditions.
5) The interrelationship between the therapeutic efforts and occurrence of the renal infarctions and glomerular thrombosis should awaits further clarification in future, however, complicated and intense modes of treatment may be closely related with the increasing incidences of these conditions.
6) No essential difference of the renal cortical necrosis and renal infarctions is observed from histo-pathological point of view. The difference exists only in the extent and degree of the morbid changes in both conditions.
7) Revalent to the arterial trees in the renal infarctions, the most striking thrombo-necrotic change is discernible in the vas afferens adjacent to the glomeruli. The attention should be paid on a fact that the arterial branches of the designated lesions are involved in acute and remarkable circulatory disturbance, representing the pretlirombotic lesions. Moreover, rectus arteries, capillary vessels distributing the interstitium of the urinary tubules and veins of rather larger sizes are involved in circulatory disturbance associated with thrombus formation. The above-mentioned observation may support a view that the circulatory derangement involving the venous system is also act as important contributory fact for causation of the conditions.
8) Based on the observation, it is appropriate to justify that the theoretical basis of the functional derangement of the designated distributing arteries which is clearly defined as the "Renal ischemia with failed reflow" by Sheehan and Davis will be applied for clarifying the pathogenesis of the renal cortical necrosis and infarction. Thus it is concluded that the conditions should be explained on this theoretical basis as applied to the similar lesions in brain and heart as described by other authors in our laboratories.

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1) Effects of electrical stimulation of the brain stem upon EEG activities in both hippocampi and neocortex were studied in the rabbit in the acute experiment. The animal was lightly anesthetized with Nembutal and immobilized with D-tubocurarine. The arterial blood pressure was monitored in the femoral artery.
2) High frequency stimulation of the brain stem (200 μsec pulses at 50-100/sec) produced EEG spikes in both hippocampi, suppressing the theta rhythm. Occasionally, this phenomenon outlasted the stimulation.
3) Low frequency stimulation (200 μsec pulses at 2-10/sec) induced essentially the same results in both hippocampi.
4) The neocortical EEG showed either desynchronization or spikes during low frequency stimulation. High frequency stimulation induced spikes and, in some cases, a spindle burst.
5) The effects of high frequency stimulation upon EEG activities in both hippocampi and neocortex preceded the increase in blood pressure.
6) These results suggest that the stimulated area could exert deactivating effect upon hippocampal EEGs.

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Changes in visual evoked potentials (VEP) induced by tricyclic antidepressants in patients with endogenous depression were studied.
VEP was recorded 3-5 times consecutively before and during the treatment. Drug-induced changes in the amplitude-ratios of P₁₀₀ of VEP after loading mental tasks as well as the changes in the amplitude and latency of the baseline VEP before the tasks were studied during the treatment with amitriptyline (AMP) or imipramine (IMP).
The results were as follows :
1) The amplitude-ratios after loading the tasks increased at least once in the course of the treatment with AMP or IMP. The increase reached the level of statistical significance only when the doses of more than 75 mg per day were given.
2) With the doses of less than 75 mg per day the amplitude-ratios after the tasks scarcely showed any changes in patients treated with AMP, but showed a slight increase in patients with IMP.
3) In cases of continuous high dose administration of the drugs re-decrease of the amplituderatios sometimes occurred. The re-decrease was more often seen in patients treated with AMP than in those with IMP.
4) While amplitude of P₁₀₀ of the baseline VEP before the tasks tended to decrease according to the dose increase in patients treated with AMP, no consistent changes were seen in patients with IMP regardless of the dose. No relationship was observed between P₁₀₀ latency and the dose in patients treated with AMP, nor in those treated with IMP.
From these results, it is inferred that both AMP and IMP simultaneously affected stimulatory and inhibitory processes in depressive patients, and that AMP showed stronger inhibitory effects and IMP stronger stimulatory ones.

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