Schistosoma mattheei infection in cattle: the course of the intestinal syndrome, and an estimate of the lethal dose of cercariae.

Three groups of young oxen were infected percutaneously with cercariae of Schistosoma mattheei. Three of five oxen infected with 248 cercariae kg-1 mass died or were killed in extremis 58-70 d after infection, a fourth survived extremely severe clinical schistosomosis and the fifth was only slightly affected. None of seven calves infected with 187 cercariae kg-1 died, while one of seven exposed to 119 cercariae kg-1 was in extremis (possibly not from schistosomosis) when killed after 378 d. The LD50 appears to be in the region of the highest dose tested (248 cercariae kg-1), but depends on variations in the viability of the cercariae used. The clinical syndrome was characterized by a drastic, rapid loss in body mass; a severe diarrhoea containing blood clots; straining, gnashing of the teeth, occasional groaning, and other signs of abdominal pain; and markedly sunken eyes. Lethally infected oxen did not become recumbent until shortly before death. Some severely affected animals made remarkable, but slow, recoveries without treatment. Schistosomes, in close association with granulomata, are described-apparently for the first time-in the omental veins of cattle. Mean worm development in three calves that died or were killed in extremis in the acute stage of the disease, was 55.5%. In contrast to most previous findings with S. mattheei, in two of these animals, more female than male worms developed. The worms were recovered by perfusion and, in one animal, a large number of intestinal veins were dissected open to estimate the efficiency of the perfusion method. Only 1.9% of the total worm burden had not been removed by perfusion in this animal.

Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei.

Twenty-eight Dorper wethers, allocated according to age into 4 groups of 7 animals each, and 1 group of 7 Merino wethers, were compared for susceptibility to Schistosoma mattheei infestation. The group mean ages of the Dorper sheep varied from 5-61 months and their live mass from 25-66 kg, while the Merinos were 8 months old and had a mean mass of 19 kg. Despite the marked differences in the age and live mass of the Dorper sheep and the inclusion of 2 breeds in the experiment, no statistically significant differences were found in cercariae which failed to penetrate the sheep the mean percentage development of cercariae to adult worms, worm distribution in the mesenteric and gastric radicles of the portal vein and the pulmonary arterial system, and worms not removed by perfusion. Significant differences between groups (5% significance level) were found, however, in the number of worms recovered from the hepatic portal system, and in the worm sex ratio. On 3 occasions the total number of eggs excreted per female schistosome in the mesentery per 24 hours differed significantly between groups, but each time a different group or groups of sheep were responsible for the variation which was probably due, therefore, not to the age or breed of the sheep, but to daily variations in individuals. Highly significant differences occurred in the infectivity of the 6 cercarial pools used for infestation in spite of standardized collection and handling of the cercariae. Possible reasons for this are discussed and a solution suggested. Frequent egg counts (5 per sheep per week) were done during the first 25 days of patency, until the sheep were slaughtered. Schistosome ova were detected in the faeces of only 1/18 sheep examined on Day +43 after infestation, and 3/17 on Day +44, whereafter this increased rapidly to 15/34 on Day +45, 25/33 on Day +46, etc. A highly significant correlation was found between the total worm egg excretion in the faeces of the sheep per day and the numbers of female schistosomes in the mesentery, especially shortly after the onset of egg production.

Studies on schistosomiasis. 7. A comparison of various methods for the infestation of sheep with Schistosoma mattheei.

The percutaneous (leg and thorax and abdomen) and subcutaneous routes of infestation with Schistosoma mattheei were compared in 29 sheep. Larger percentages of cercariae developed after percutaneous than subcutaneous infestation and the difference was highly significant (P less than 0,0001). Furthermore, if the leg was used for percutaneous infestation worm development was significantly higher (P less than 0,02) when the skin was washed thoroughly in water before exposing it to cercariae, than when it was left unwashed. Washing was apparently not necessary if the thorax and abdomen served as the route of infestation.

Are there acid base changes during transurethral resection of the prostate (TURP)?

UNLABELLED: Acid base status during transurethral resection of the prostate (TURP) has been almost neglected. We therefore measured the acid base status and interpreted the observed changes according to the Stewart approach. The Stewart model focuses more on the influence of serum electrolyte concentrations on acid base changes than does the conventional Henderson-Hasselbalch approach. In 20 patients undergoing TURP, the following variables were determined: PaO(2), PaCO(2), pH(a), actual bicarbonate, standard base excess, serum concentration of sodium, potassium, chloride, lactate, and total protein. A study group (n = 11) and a control group (n = 9) were built, depending on the maximal amount of fluid absorption estimated with the aid of ethanol concentration monitoring in the expired gas. The study group developed a mild acidosis with a decrease in pH from 7.41 to 7.37 (P = 0.037), compared with a very discrete pH decrease from 7.44 to 7.42 in the control group. We found that moderate irrigant absorption during TURP leads to a specific metabolic acidosis. We speculate that larger amounts of irrigant absorption may cause a more severe metabolic acidosis. As the constellation of independently pH regulating variables appears to be typical for TURP, this acidosis could be named "TURP-acidosis." IMPLICATIONS: We measured acid base status in 20 patients undergoing transurethral resection of the prostate comparing a larger fluid absorption group with a minor or no fluid absorption group. We postulate the development of a typical metabolic transurethral resection of the prostate-acidosis caused by irrigant absorption.

Differential response of the pulmonary circulation to prostaglandins E2 and F2 alpha in the presence of unilateral alveolar hypoxia.

Pulmonary hemodynamic responses to several prostaglandins (PGs) are augmented by hypoxia. To test whether responses to vasoconstrictor PGs would be enhanced in hypoxic areas of the lung, resulting in redistribution of blood flow to well-oxygenated areas, the effects of PGE2 and PGF2 alpha were evaluated in anesthetized dogs with divided ventilation, one lung being ventilated with 100% N2 and the other with 100% O2. Thermal dilution techniques coupled with electromagnetic flow measurements permitted estimates of blood flow to each lung. After indomethacin (5 mg/kg i.v.), PGE2 at 0.01, 0.025 and 0.10 micrograms/kg/min i.v. produced significant increases in flow to the O2-ventilated lung at each dose. In addition, PGE2 increased total pulmonary blood flow, but only at the two larger doses. Concomitantly, systemic arterial PO2 increased from 104 +/- 21 to 138 +/- 26 mm Hg (P less than .001). Identical results were obtained when meclofenamate (5 mg/kg i.v.) was used to block PG synthesis. PGF2 alpha increased total pulmonary blood flow (P less than .01) only at the largest dose (0.10 micrograms/kg/min), but did not redistribute flow or increase PO2. Atrial pacing increased total pulmonary blood flow (P less than .001) and flow to both O2 (P less than .001)- and N2 (P less than .05)-ventilated lungs with no change in PO2. We conclude that PGE2 redistributes pulmonary blood flow to well-oxygenated alveoli through mechanisms not related solely to its vasoconstrictor properties or to its capacity to increase cardiac output.

Effect of ventilatory rate on renal venous PGE2 and PGF2 alpha efflux in anesthetized dogs.

In anesthetized laparotomized male mongrel dogs with ventilatory rate set at 10 breath.min-1, tidal volume was adjusted so that control arterial pH and PCO2 were within the normal range for unanesthetized dogs. Control renal venous PGE2 and PGF2 alpha concentrations were comparable to those of unanesthetized dogs, namely, 57 +/- 10 and 114 +/- 18 pg.ml-1, respectively. In contrast, control arterial plasma renin activity (PRA), 6.6 +/- 1.2 ng.ml-1.h-1, was considerably greater than in unanesthetized dogs. Stepwise increases in ventilatory rate increased renal venous PGE2 and PGF2 alpha to 109 +/- 18 and 205 +/- 41 pg.ml-1, respectively. Hyperventilation reduced PCO2 and increased pH and PRA but had no effect on renal blood flow, arterial blood pressure, or arterial PGE2 and PGF2 alpha concentrations. When the ventilatory rate was returned to control levels, pH, PCO2, PRA, and renal venous PGE2 and PGF2 alpha concentrations returned to control. Ventilatory rate or some consequence of altering ventilatory rate is, therefore, a determinant of renal venous efflux of PGE2 and PGF2 alpha. Moreover, it may be a more important determinant of "resting" concentrations of prostaglandins in renal venous blood than anesthesia, laparotomy, or PRA.

Alterations in the fraction of oxygen in inspired gas affect rates of renal prostaglandin E2 synthesis in anesthetized dogs.

Reductions of oxygen in inspired gas from 20% to 15%, in anesthetized dogs, reduced arterial PO2 and increased the renal efflux of PGE2 but not PGF2a. Renal blood flow, blood pressure, plasma renin activity as well as arterial pH and PCO2 were unaffected PGs may mediate the renal hemodynamic or excretory consequences of alterations in PO2. In addition, minor variations in PO2 might account, in part, for the variable renal venous PGE2 concentrations reported under basal conditions.