Comparison of haemodynamic effects of oral hydralazine and prazosin hydrochloride in patients with chronic congestive heart failure

The comparative haemodynamic effects of oral prazosin hydrochloride and hydralazine were evaluated in 11 patients with chronic congestive heart failure. The maximum total dose of prazosin received by an individual varied up to 25 mg. Ten patients received a maximum of 75 mg and one received 50 mg of hydralazine at six-hour intervals. There was no significant change in heart rate with either drug. Decrease in mean arterial and left ventricular filling pressures were modest and similar with both agents. With prazosin, the average cardiac index increased 20 per cent and systemic vascular resistance decreased 20 per cent. By contrast, hydralazine increased cardiac index by 58 per cent and decreased systemic vascular resistance by 40 per cent. The increase in stroke work and stroke volume indices was significantly greater with hydralazine than with prazosin. These findings suggest that in some patients with severe chronic congestive heart failure, improvement in left ventricular performance may be greater with hydralazine than with prazosin.

Host dietary starch and Moniliformis (Acanthocephala) in growing rats

During the course of three experiments, groups of male weanling rats were allowed to feed ad libitum on isoenergetic diets containing 0, 1, 2, 3 and 4% starch. The growth of rats, which were infected with either 20 or 40 cystacanths of Moniliformis dubius , was compared with the growth of similar uninfected rats which had been fed on the same diet. No differences could be detected between the uninfected and infected rats for a given diet apart from the lowered liver glycogen of the infected rats which had consumed the diet containing most starch during one of the experiments. Under the experimental conditions used, the growth of both the host and the parasite appeared to be closely related to the amount of starch ingested by the host. Thus, the results may be interpreted as demonstrating that the presence of a suitable source and quantity of available glucose in the diet of the rat is important for the growth of Moniliformis .

McArdle disease: the mystery of reappearing phosphorylase activity in muscle culture--a fetal isoenzyme

To understand the apparently paradoxical appearance of phosphorylase in muscle cultured from patients with McArdle disease, the enzyme in muscle culture was studied immunologically and electrophoretically. Antibody against normal human muscle phosphorylase completely inhibited the enzyme of adult muscle, but it had no effect on phosphorylase activity of muscle cultures from normal individuals or patients with McArdle disease. Also, amounts of antibody that would completely inhibit phosphorylase in mature muscle left about 30% of the activity in muscle obtained from human fetus at four months' gestation. Acrylamide-disc and slab-gel electrophoresis showed a single band of phorphorylase activity in adult muscle and two bands in fetal muscle. This suggested that at four months' gestation, both fetal and mature forms are present but that only the mature isoenzyme is inhibited by the antibody. The enzyme from cultured muscle gave only a single band, with the electrophoretic mobility of the fetal isoenzyme. These data suggest that phosphorylase activity in muscle cultured from patients with McArdle disease is due to a fetal isoenzyme whose genetic control is different from that of the mature enzyme.

Dietary relations between Moniliformis (acanthocephala) and laboratory rats

Aspects of the course of infection of Moniliformis dubius in male rats fed on four purified, isocaloric diets (A, B, C and D) were investigated. Diet A contained no digestible carbohydrate, diet B contained glycerol as a potential source of glucose, diet C contained 3.6 % starch and diet D contained about 59 % starch. After a rat had been adapted to one of the diets, it was infected orally with 20 cystacanths of Moniliformis and allowed to continue feeding on the same diet for periods varying from 1 to 18 weeks. A group of 4 rats was studied in this way on each of the diets for 11 weeks and on diets C and D for a further 7 weeks. The effects of the dietary treatments on the rats were studied by measuring their food intake, growth rate and liver glycogen. At the end of each experi­mental period, the rats were killed and the numbers, location, dry masses and state of reproduction of the worms were recorded. The composition of the diet appeared to have no effect on the establishment of Moniliformis in the small intestine and the populations of worms emigrated against the direction of gastrointestinal flow during the first month of the course of infection irrespective of the diet of the host. Worms from the rats fed on diets A and B hardly grew, their survival in their hosts did not appear to continue after 11 weeks and they showed no evidence of reproductive activity. Worms from rats fed on the low starch diet (C) did not grow as rapidly as those from rats fed on the high starch diet (D) during the first few weeks of the infection, but eventually they grew much larger and lived longer than worms from the hosts feeding on the high starch diet. Worms in the rats fed on diet C appeared to remain in a precise location in the anterior part of the small intestine from 4 weeks after infection of the host until the end of the experimental period. Worms in the rats fed on diet D had begun to move posteriorly in the small intestine from about 7 weeks after the infection of the host. The results of an experiment involving the transfer of rats with established infections of Moniliformis from a standard laboratory diet to diets A, B, C and D supported the conclusion that the survival, growth and reproduction of Moniliformis are dependent on the availability of glucose liberated during digestion in the host. Another experiment demonstrated that Moniliformis can survive periods of at least 14 days during which the host is deprived of an essential amino acid.

The number and size of ovarian balls of Moniliformis (Acanthocephala) from laboratory rats

By means of conventional light microscopical and counting procedures, estimations have been made of the average number and size of ovarian balls from unfertilized and fertilized female Moniliformis dubius. The observations were made on worms recovered from experimental primary infections lasting 1, 2, 3, 4, 5, 8, 11, 14, 17 and 20 weeks in male rats. The number of ovarian balls rises to about 6300 per worm, with the maximum being attained more rapidly in unfertilized than in fertilized females. On average more ovarian balls were present in unfertilized than in fertilized females, but a marked decline in number occurred in both groups of worms towards the end of the experimental period. Similarly, on the basis of the area within the elliptical profiles of fixed ovarian balls, it appeared that those from unfertilized females were generally larger on average than those from fertilized worms.

Bilateral pneumothoraces and subcutaneous emphysema: a complication of internal jugular venepuncture

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