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Yersinia, Campylobacter, Plesiomonas and Aeromonas are known causative agents in waterborne diseases. For about 10 years, outbreak of diarrhea has been observed, especially among children, in the mountain areas of Okayama. Y. pseudotuberculosis recently isolated from non-chlorinated drinking water sources such as mountain streams and wells has been suspected to be the causative bacteria of the disease. Attempts were made to isolate Yersinia and Campylobacter from water samples from rivers in rural areas and Plesiomonas and Aeromonas from samples of well water and fresh water fishes in Okayama prefecture from 1987 to 1990. The isolation rate of Yersinia from river water samples was 7.5% with a higher rate in the mountain areas than in the nonmountain areas. While Y. enterocolitica was isolated throughout the year, Y. pseudotuberculosis was only seen during the winter. Various serogroups including human types of Y. enterocolitica and serogroup 2B, 4A and UT of Y. pseudotuberculosis were detected. Campylobacter was isolated from 0.5% of river water samples. Plesiomonas from 1.5% of fresh water fishes, and Aeromonas was isolated from 6.9% of well water samples and 47.1% of fresh water fishes.
Fresh water obtained from nine sources was shown to cause inactivation of poliovirus. Further testing with four of these water samples showed that enteric viruses from different genera were consistently inactivated in these freshwater samples. Studies on the cause of inactivation were conducted with echovirus type 12 as the model virus. The results revealed that the virucidal agents in the waters tested could not be separated from microorganisms. Any treatment that removed or inactivated microorganisms caused loss of virucidal activity. Microbial growth in a sterilized creek water seeded with a small amount of stream water resulted in concomitant production of virucidal activity. When individual bacterial isolates obtained from a stream were grown in this sterilized creek water, most (22 of 27) produced a large amount of virucidal activity, although the amount varied from one isolate to the next. Active and inactive isolates were represented by both gram-positive and gram-negative organisms. Examination of echoviruses inactivated in stream water revealed that loss of infectivity first correlated with a slight decrease in the sedimentation coefficient of virus particles. The cause appeared to be cleavage of viral proteins, most notably, VP-4 and, to a lesser extent, VP-1. Viral RNA associated with particles was also cleaved but the rate was slower than loss of infectivity. These results suggest that proteolytic bacterial enzymes inactivate echovirus particles in fresh water by cleavage of viral proteins, thus exposing the viral RNA to nuclease digestion.
Freshwater catfish, Heteropneustes fossilis, were injected daily intraperitoneally either with vehicle (0.05 ml of 95% ethanol/100 g body wt) or vitamin D3 (50 I.U./100 g body wt) and maintained in artificial fresh water, calcium-rich fresh water, or calcium-deficient fresh water for 10 days. The specimens were sacrificed on Days 1, 3, 5, and 10 after initiation of the experiment. The blood samples were collected on these intervals and serum calcium and inorganic phosphate levels were analyzed. Vitamin D3 induced hypercalcemia and hyperphosphatemia in the freshwater catfish, H. fossilis. These effects of vitamin D3 are not dependent upon the calcium concentration of the different ambient media used in this study.
14C-labeled flumequine was administered as a single oral (5 mg kg(-1), 86 microCi kg(-1)) or intravenous (5 mg kg(-1), 82 microCi kg(-1)) dose to Atlantic salmon Salmo salar held in sea water or in fresh water. The absorption, tissue distribution and elimination were determined by means of liquid scintillation counting and whole-body autoradiography. The drug was rapidly absorbed and extensively distributed in all groups of fish. Radiolabeled compound was present in blood and muscle for more than 8 wk in the freshwater groups. In the seawater groups, however, no radioactivity was detected in the blood and muscle after 4 d and 2 wk, respectively. It was concluded that flumequine was eliminated at a substantially higher rate from Atlantic salmon in sea water than in fresh water.
The effects of immersion of the lower leg and foot in fresh water and in carbon dioxide (CO2)-enriched water (1200 mg CO2 per kg water; succinate+sodium bicarbonate: Actibath, KAO Tokyo) on cutaneous circulation, vasomotion and oxygen tension (PO2) were measured by laser Doppler flowmetry and transcutaneous oximetry. On the first of two consecutive days patients were randomly assigned to have the lower extremities immersed in either fresh water or CO2-enriched water under standardized conditions (temperature, 34 degrees C; depth, 35 cm; immersion time, twenty minutes) with concurrent measurement. On the second day patients were switched to the other bath type. For both sets of measurements probes were attached symmetrically to the dorsum of each foot. Included in the study were 18 patients with mild, bilateral, peripheral, occlusive arterial disease (intermittent claudication, femoral or iliac type). During immersion in CO2-enriched water the Doppler laser signal and vasomotion amplitude rose by 300%, while PO2 increased by 10%. These increases were still apparent during the latter part of the measurement period, following withdrawal of the limbs from the bath, while patients were seated and supine. During immersion in fresh water and thereafter the Doppler laser signal was unchanged and the PO2 increase was considerably less marked. The authors were thus able to demonstrate vasodilation and increased oxygen utilization (Bohr effect) resulting from topical CO2 application, and hence, that the use of topical CO2 has an objective basis.
Juvenile milkfish Chanos chanos (Forsskål, 1775) were transferred from a local fish farm to fresh water (FW; 0 per thousand ), brackish water (BW; 10 per thousand, 20 per thousand ) and seawater (SW; 35 per thousand ) conditions in the laboratory and reared for at least two weeks. The blood and gill of the fish adapted to various salinities were analyzed to determine the osmoregulatory ability of this euryhaline species. No significant difference was found in plasma osmolality, sodium or chloride concentrations of milkfish adapted to various salinities. In FW, the fish exhibited the highest specific activity of Na, K-ATPase (NKA) in gills, while the SW group was found to have the lowest. Relative abundance of branchial NKA alpha-subunit revealed similar profiles. However, in contrary to other euryhaline teleosts, i.e. tilapia, salmon and eel, the naturally SW-dwelling milkfish expresses higher activity of NKA in BW and FW. Immunocytochemical staining has shown that most Na, K-ATPase immunoreactive (NKIR) cells in fish adapted to BW and SW were localized to the filaments with very few on the lamellae. Moreover, in FW-adapted milkfish, the number of NKIR cells found on the lamellae increased significantly. Such responses as elevated NKIR cell number and NKA activity are thought to improve the osmoregulatory capacity of the milkfish in hyposaline environments.
Low doses of arginine-vasotocin (AVT), isotocin and oxytocin (1 pg-1 ng/kg body weight) were antidiuretic in eels adapted to fresh water but not in those adapted to sea-water. High doses (more than 10 ng/kg) were always diuretic. No effects on tubular water reabsorption were observed and the glomerular filtration rate (GFR) was proportional to the maximum reabsorptive rate for glucose (Tm(glucose)) in eels adapted to sea-water. Increases in urinary flow appeared therefore to result from glomerular recruitment. Infusion of AVT or isotocin at low rates reduced the GFR and urinary flow of freshwater eels to the levels found in seawater eels. Vasopressin (lysine or arginine) had no direct effect on kidney function in freshwater eels but blocked both the diuretic and antidiuretic actions of the other hormones. When infused into seawater eels it was diuretic. This effect could have been due to blockade of the actions of endogenous AVT and/or isotocin.
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During the period from October 1982 to July 1984, a total of 1,157 specimens that consisted of 132 river and lake water, 514 river and lake muds, and 511 fresh-water fish caught in both Tama River and Sagami River were examined the presence of the organisms. Of them, 132 (100%) river and lake waters, 304 (59.1%) river and lake muds, and 462 (90.4%) intestinal contents of fresh-water fish were found to have harbor a mean concentration of 1.3 x 10(3)/l, 1.6 x 10(6)/g, and 1.1 x 10(6)/g of motile-Aeromonas respectively. However, nonseasonal variation was observed in the incidence of the organisms throughout the period of investigation. When attempts were made to classify the isolates by the method described Popoff et al., 17 (14.2%) of 120 water-isolates were typed as A. hydrophila, 33 (27.5%) as A. sobria and 35 (29.2%) as A. caviae respectively. And the rest of the 35 (29.2%) remained untypable. As for the 176 mud-isolates, 38 (21.6%) were typed as A. hydrophila 23 (13.1%) as A. sobria and 41 (23.3%) as A. caviae respectively. And the rest of 74 (42.0%) remained untypable. Some efforts were made on the 1,056 strains obtained from fresh-water fish, and 182 (17.2%) were typed as A. hydrophila, 332 (31.4%) as A. sobria and 206 (19.5%) as A. caviae respectively. And the rest of the 336 (31.8%) remained untypable.