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Biomedical subjects

G S Nelson

Publications and source records attributed to G S Nelson.

At least 73 records · Page 4Linked to original sources
PubMed1975

Effect of drinking water temperature on broiler performance.

In the first experiment, higher body weight gain and feed comsumption were attained with water at a temperature of 23.9 degrees C. as compared with 35.0 degrees C. No significant differences in feed efficiency due to water temperature were evident. Livability was significantly reduced during brooding for the birds given warm water (35.0 degree C). A significant interaction for body weight gain was observed between the initial ambient air brooding temperatures and water temperatures during the growing period. In the second experiment six water temperatures during brooding to three weeks of age were studied. Body weight gain and feed comsumption were significantly depressed at a drinking water temperature of 40.6 degrees C. as compared with drinking water temperatures between 17.8 degrees C. and 35.0 degrees C. No differences in livability were noted which was in contrast to the results of the first experiment. A drinking water temperature below ambient air temperature is apparently beneficial to the growth of the broiler chick. The placement of the waterers in relation to the brooder stoves could influence water temperature which would affect the growth of broilers.

Acclimatization↗
PubMed1975

Studies with Brugia pahangi. III: Histological changes in the affected lymph nodes of infected cats.

Cats infected with Brugia pahangi by single or repeated inoculation of infective larvae for different periods of time, were autopsied and the affected lymph nodes examined histologically, stained with methyl green and pyronin Y, haematoxylin and eosin, Lendrum's eosinophil stain, Mallory's trichrome stain or the May-Grunwald Giemsa technique. In single infections, there was initially a cell-mediated type immunological response which was characterized by proliferation of mononuclear thymus-dependent cells in the paracortical region of the lymph node. The antibody-type response became more evident as the infections progressed. This response was characterized by proliferation of lymphocytes in rapidly enlarging germinal centres and the production of large numbers of plasma cells in the cortico-medullary junction and medullary cords of the nodes. In long term infections, the affected afferent lymphatic vessel and popliteal node were almost obliterated by fibrous tissue, but an inguinal lymph node complex usually developed to replace lymphatic filtration in the limb. Repeated infections produced more complicated changes. Both types of response occurred to varying degrees throughout the infection. No significant increase in mast cells or eosinophil cells was seen. Fibrous tissue increased in the lymph nodes only after long periods of infection; such nodes often became non-functional, and by-passed by new lymphatic vessels.

Animals↗
PubMed1975

Ackertia globulosa sp. n. (Nematoda: Filarioidea) from rodents in Kenya.

Ackertia globulosa sp. n. (Nematoda: Filarioidea) is described from the pulmonary arteries of the striped mouse, Lemniscomys striatus striatus (L.), in Kenya. Distinguishing features are the small size of the adults; the short left spicule and arrangement of the caudal papillae (3 pairs preanal, 4 pairs postanal) of the male; small projecting lobes on the tail of the females; and 10 to 12 refractile globules in the microfilarial sheath. The microfilariae are found in the skin, mostly of the ear. The probable intermediate host is a hard tick, Haemaphysalis leachi.

Animals↗
PubMed1973

Studies on heterologous immunity in schistosomiasis. 7. Observations on the development of acquired homologous and heterologous immunity to Schistosoma mansoni in baboons.

Observations were made on the development of immunity to Schistosoma mansoni in baboons using both homologous and heterologous systems. The baboons were immunized by either (a) a single exposure to cercariae of the homologous species S. mansoni, or (b) 1-2 exposures to cercariae of either a S. rodhaini/S. mansoni hybrid or a S. mattheei/S. haematobium hybrid, or (c) repeated exposure to the cercariae of S. rodhaini or S. bovis. Baboons immunized with 500 cercariae of the homologous parasite developed partial immunity to reinfection, as did the baboons immunized with multiple exposures to the heterologous cercariae of S. rodhaini and S. bovis, although these parasites produced neither adult worms nor eggs in the baboons. The hybrids gave rise to well-established adult worm infections, but produced less immunity, even though the S. rodhaini/S. mansoni hybrid was genetically very similar to S. mansoni. These results indicate that adult worms are not essential to produce a considerable degree of immunity to reinfection, which can be engendered by the earlier stages of the parasites. However, none of the immune responses prevented egg deposition in the tissues, and considerable pathological changes resulted from the challenge infection. These observations suggest that although heterologous infections show some promise as immunizing agents, further studies are needed of the pathological changes resulting from their use.

Animals↗