The guineapig as an experimental host of the meningeal worm, Pneumostrongylus tenuis Dougherty

Infective larvae ofP. tenuisgiven orally to guineapigs, penetrated the stomach wall and reached the body cavity. Some dispersed in the omentum extending along the greater curvature of the stomach. Others wandered into and through the liver. Some migrated through the diaphragm or along the mesentery ensheathing the hepatic vein and the vena cava. In the pleural cavity some penetrated the pericardium, and the pleura and parenchyma of the lungs. Numerous larvae were overcome by the host in the mesentery, particularly the omentum.

The experimental transmission of Pneumostrongylus tenuis to caribou (Rangifer tarandus terraenovae)

Two caribou calves (Rangifer tarandus terraenovae) were infected experimentally with Pneumostrongylus tenuis Dougherty from white-tailed deer (Odocoileus virginianus borealis). The female calf showed slight neurologic signs from the 5th to the 14th day when she died from a mycotic infection. The male calf first showed neurologic signs on the seventh day. These signs became progressively more extreme and by the 29th day, when the animal was necropsied, it showed severe locomotory ataxia with knuckling and posterior weakness. Histological study of the spinal cord of the male revealed numerous worms in all regions of the spinal cord and in the brain stem and medulla oblongata. Traumatic lesions and worms were unusually numerous in lateral and dorsal funiculi. It is suggested that the more severe neurologic signs were caused by migration of worms into funiculi from dorsal horns of grey matter. The results are discussed in relation to the management of woodland caribou in eastern North America.

Dirofilaria (Nochtiella) infestation in a human in Ontario

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The comparative morphology of cephalic structures in the superfamily filarioidea (Nematoda)

Cephalic structures in 62 genera of the nematode superfamily Filarioidea are compared. Vestiges of pseudolabia do not occur in filarioids and the persistence of internal cephalic papillae in some genera indicates that this superfamily branched off early from a stem which also gave rise to the Spiruroidea. The hypothesis of Chabaud (1955) on the formation of papillae patterns in filarioids is followed generally but Pseudofilaria is regarded as the most primitive type which links the filarioids to the spiruroid family Thelaziidae. The condition of only four papillae, known conclusively only in Splendidofilaria, may have resulted from fusion of pairs of external papillae since in several genera there is a tendency towards fusion. Tetracheilonema, Litomosoides, and perhaps other genera (e.g. Icosiella, Setaria equina) apparently fall outside the main line of evolution which led to the commonest pattern of four pairs of submedian papillae (external papillae). Study of the cephalic ends of filarioids reveals characters useful in the identification of species.

Congenital cardiac disease associated with polysplenia. A developmental complex of bilateral "left-sidedness"

The well-recognized association of congenital cardiac disease with asplenia has been termed "bilateral right-sidedness" or dextro-isomerism, since the spleen is absent, the liver is symmetrical, and each lung has three lobes and an epiarterial bronchus. In a study of pathological material from 12 patients with congenital cardiac disease associated with multiple spleens (as contrasted to accessory spleen), we found a definite tendency for the symmetrical development of organs but with a tendency for bilateral left-sidedness or levo-isomerism.

The abnormalities assumed one of three forms as follows: (1) absence of a normal right-sided structure, (2) bilateral organs, each with the structure of a left-sided organ, or (3) excessive tissue of a left-sided organ. Thus, in polysplenia we observed a tendency for (1) absence of the hepatic segment of the inferior vena cava and absence of the gallbladder, (2) two lobes in each lung with hyparterial bronchi, and (3) multiple spleens. Other noncardiac abnormalities were partial or complete abdominal heterotaxia and partial malrotation of the bowel. The cardiac malformations included dextrocardia, bilateral superior venae cavae, anomalous pulmonary venous connection with malposition of the atrial septum, and defects in the atrial septum and in the ventricular septum.

Our study suggests that the developmental complex of multiple spleens is closely related to the asplenic syndrome, with the important difference being left-sided symmetry rather than right-sided symmetry.

Phenylketonuria-the guthrie screening test-a method of quantitation, observations on reliability and suggestions for improvement

The Guthrie bacterial inhibition assay method of screening neonatal infants for phenylketonuria (pku) initiated mass screening for inborn errors of metabolism. It is a simple, cheap procedure admirably suited to private local use as against private or public central use. However, using parallel fluorometric determinations as a basis for comparison, and 4 mg per 100 ml serum phenylalanine as a presumptive positive threshhold, the Guthrie test yielded 53 per cent "false negatives." Extrapolating from a combination of our data and reported phenylalanine levels at three days of age or less in proved pku patients, it is estimated the Guthrie test might fail to detect one of 25 pku patients screened at three days of age or less. Means to diminish this risk are considered.