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Biomedical subjects

J V Ernst

Publications and source records attributed to J V Ernst.

At least 55 records · Page 3Linked to original sources
PubMed1977

Anthelmintic activity of albendazole against gastrointestinal nematodes in calves.

Anthelmintic activities of albendazole were evaluated in a controlled experiment. Forty calves experimentally infected with gastrointestinal nematodes were allotted to 4 groups. Calves in group 1 were used as nonmedicated controls; calves in groups 2, 3, and 4 were given (by oral route) a suspension containing albendazole at dose concentrations of 2.5, 5.0, and 7.5 mg/kg of body weight on the 35th day after administration of infective nematode larvae. In groups 2, 3, and 4 calves, average overall reductions (based on geometric means) were 77.1, 93.6, and 98.1%, respectively. These reductions were highly significant (P less than 0.01) in calves given doses of 5.0 and 7.5 mg/kg, and were significant (P less than 0.05) in calves given the 2.5-mg/kg dose. Ostertagia ostertagi, Trichostrongylus axei, Cooperia onchophora, Cooperia punctata, and Oesophagostomum radiatum removals at the 5.0- and 7.5-mg/kg dose levels were all highly significant (P less than 0.01); whereas, removals of Haemonchus contortus were not significant, even at the 7.5-mg/kg dose level.

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PubMed1976

Ultrastructure of macrogametogenesis of Eimeria mivati.

The development of the macrogamete of Eimeria mivati Edgar and Seibold 1964 was studied with the electron microscope. Development of the young gamont was characterized by a loss of organelles such as the apical complex, subpellicular microtubules, rhoptries and micronemes, followed by an increase in micropores, mitochondria, rough endoplasmic reticulum (rER), and Golgi complexes. Nuclear detachment bodies and canaliculi were present in maturing macrogamonts. Amylopectin was first observed as small electron-dense rod-like bodies that eventually became large electron-transparent bodies. Type II wall-forming bodies developed in the cisternae of the rER. Type I wall-forming bodies appeared shortly thereafter in close association with numerous Golgi complexes. Many small vesicles located between the cisternae of the rER and the Golgi complexes formed what appeared to be a secretory pathway whereby protein formed in the cisternae and, modified by the Golgi complex, may produce the type I wall body material. The outer wall of the oocyst developed between two distal membranes on the surface of the macrogamete. Although the actual mechanism of deposition of the wall material was not seen, it was probably by some secretory process. Wall-forming bodies did not fuse.

Animals↗
PubMed1976

Redescription of oocysts of the bovine coccidia Eimeria bukidnonensis Tubangui 1931 and E. wyomingensis Huizinga and Winger 1942.

Oocysts of Eimeria bukidnonenisis and E. wyomingensis were found to be morphologically similar, and could be reliably differentiated only by measurements. Pyriform oocysts of E. bukidnonensis measured 43 to 51 by 30 to 35 mum (mean 47.4 by 33.0 mum); sporocysts were 18 to 21 by 9 to 11 mum (mean 19.6 by 9.8 mum). Micropyle present; polar granule, oocyst residuum, and sporocyst residuum absent. Oocyst wall of 2 layers, 3.5 mum thick, and dark brown. Pyriform oocysts of E. wyomingensis measured 36 to 44 by 26 to 30 mum (mean 39.9 by 28.3 mum); sporocysts were 17 to 20 by 8 to 10 mum (mean 18.7 by 8.6 mum). Micropyle present; polar granule, oocyst residuum, and sporocyst residuum absent. Oocyst wall of 2 layers, 2.5 mum thick, and colored brown. The width of the oocyst was the most reliable criterion for differentiating the 2 species.

Animals↗
PubMed1976

Alkaline phosphatase activities in intestinal mucosa from calves infected with Cooperia punctata and Eimeria bovis.

Thirty calves 12 weeks of age raised under essentially parasite-free conditions were used to determine the effects of Cooperia punctata and Eimeria bovis (in single and combination infections) on mucosal alkaline phosphatase activities at 8 locations in the small intestine. In experiment 1, 5 calves infected with C punctata 3 weeks previously had highly significant (P less than 0.01) reductions in mucosal alkaline phosphatase activities compared with those in 5 noninfected control calves. These reductions were greatest in the 2 locations of the intestine closest to the pylorus. Infected calves had a mean of 44,356 C punctata adults present. In experiment 2, 5 calves infected with E bovis 2 weeks previously had significant (P less than 0.05) reductions in mucosal alkaline phosphatase activities compared with those in 5 noninfected control calves. These reductions were present in the caudal half of the intestine. Numerous 1st-generation E bovis schizonts were present in the caudal third of the intestine. In experiment 3, 5 calves infected with C punctata and E bovis of the same durations as in experiments 1 and 2 had highly significant (P less than 0.01) reductions in mucosal alkaline phosphatase activities in the cranial half of the intestine compared with those in the controls. These reductions were much larger than in either of the monospecific infections (experiments 1 and 2). A mean of 31,968 adult C punctata were recovered from the infected calves, and numerous E bovis schizonts were observed in the caudal third of the intestine.

Alkaline Phosphatase↗
PubMed1975

The ultrastructure of macrogametes of Eimeria ferrisi Levine and Ivens 1965 in Mus musculus.

Macrogametes of Eimeria ferrisi occurred in epithelial cells of the cecum and colon of Mus musculus and were studied by electron microscopy. Young stages were identified as macrogamonts by the presence of wall-forming bodies. At first an outerlimiting membrane and remnants of the inner membrane complex of the former merozoite pellicle were present; the latter was later lost but in mature macrogametes 3 limiting membranes were observed. Type II wall-forming bodies appeared before type I; the former developed in expanded cisternae of the endoplasmic reticulum whereas the latter were smaller in size and appeared in the ground substance of the cytoplasm. After formation of the oocyst wall the bodies of the 2 types were no longer visible. The presenceodies of the 2 types were no longer visible. The persistence of micronemes in mature macrogametes and the presence of numerous layers of rough endoplasmic reticulum during wall formation have not been previously reported.

Animals↗
PubMed1975

A fine structural study of asexual stages of the murine coccidium Eimeria ferrisi Levine and Ivens 1965.

The schizogony of Eimeria ferrisi was studied in experimentally infected Mus musculus. Developmental stages occurred in epithelial cells of the cecum and colon. During transformation of invasive stages into schizonts the inner membrane complex of the pellicle, the conoid, subpellicular microtubules and micronemes gradually disappeared. The micropore, however, seemed to persist. Dividing nuclei had eccentric intranuclear spindles consisting of microtubules which extended between 2 centrocones, in close relationship with centrioles. During the last nuclear division anlagen of merozoites appeared as extensions on the surface of schizonts. The outer single membrane of the schizont became the outer membrane of the merozoite pellicle. Cytoplasmic organelles, typical of eimerian merozoites were incorporated into the developing merozoites. Finally the merozoite became detached leaving behind a residual cytoplasm. Fully developed merozoites had a 3-layered pellicle, the outer single unit membrane was continuous around the merozoite with the inner complex having interruptions at the anterior and posterior poles and at the micropores. Thirty-two subpellicular microtubules, originating at the anterior polar ring extended to the posterior region of each merozoite. The apical complex consisted of a conoid, preceded by 2 rings and surrounded by a polar ring. Two rhoptries were present having club-shaped terminal ends and slender ductules in the conoid region. Some merozoites had enlarged rhoptries, with the distal vesical appearing dense and osmiophilic. The Golgi complex, endoplasmic reticulum, mitochondria, polysaccharide granules were similar to those seen in other eimerian merozoites.

Animals↗
PubMed1975

Coccidia of sandhill cranes, Grus canadensis.

Eimeria gruis Yakinoff and Matschoulsky 1935, Eimeria reichenowi Yakimoff and Matschoulsky 1935, and an Adelina species are described from sandhill cranes in the United States. E. gruis was found in the feces of 11 of 14 Florida sandhill cranes (Grus canadensis pratensis) and 62 of 72 greater sandhill cranes (G. c. tabida) from Florida, 5 of 14 greater sandhill cranes from Arizona, and 4 of 16 lesser sandhill cranes (G. c. canadensis) from Texas. E. reichenowi was found in the feces of 12 of 14 Florida sandhill cranes and 66 of 72 greater sandhill cranes from Florida, 4 of 14 greater sandhill cranes from Arizona, and 5 of 16 lesser sandhill cranes from Texas. Adelina sp. was found in the feces of 3 of 14 Florida sandhill cranes and 2 of 72 greater sandhill cranes from Florida. The Adelina species is considered to be a spurious parasite of the cranes.

Animals↗