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Biomedical subjects

J R Georgi

Publications and source records attributed to J R Georgi.

At least 37 records · Page 2Linked to original sources
PubMed1982

Quantification of Schistosoma mansoni in mouse lungs by radioassay and autoradiography of 75Se-labeled schistosomula.

Lung radioassay and compressed lung autoradiography of 75Se-labeled schistosomula were used to quantify lung schistosomula. Recovery of schistosomula from minced lung tissue after a 4-hr incubation yielded 69.4 +/- 6.3% of the total number present as demonstrated by subsequent autoradiography of these tissues. Radioassay of lung tissue was considered a valid alternative to autoradiography only for parallel comparisons and those not requiring estimation of the actual number of schistosomula. The number of schistosomula in the lungs on day 6 was significantly correlated with radioactivity in the tail on day 1 (r2 = 91.8%). It was concluded that compressed lung autoradiography provides both an alternative to and an adjunct to standard schistosomulum recovery techniques in the assay of early S. mansoni infections.

Animals↗
PubMed1980

Equine verminous arteritis; efficiency and speed of larvicidal acitivty as influenced by dosage of albendazole.

Albendazole was effective in destroying Strongylus vulgaris larvae in verminous lesions of the cranial mesenteric artery when administered as a 20% suspension by stomach tube to ponies. Fifty mg/kg body weight administered twice a day for 2 days caused death and gradual disintegration of larvae over a period of 3 to 6 weeks with mild toxic signs appearing in 3 of 11 ponies. Higher total doses of albendazole (50 mg/kg twice a day for 4 days and 25 mg/kg three times a day for 5 days) lead to more rapid disintegration of the larvae but fatal toxicity was observed in 3 of 6 ponies so treated. In all cases, resolution of verminous arterial lesions was delayed until larva remains had disappeared from the lesions. A non-parametric analysis was applied to combined radiographic, pathologic and parasitologic observations and data for testing their statistical significance

Administration, Oral↗
PubMed1979

Equine verminous arteritis. An arteriographic evaluation of the larvicidal activity of albendazole.

Albendazole was an effective larvicidal anthelmintic against the fourth stage Strongylus vulgaris larvae as late as one month post-infection. The drug was administered at a dose rate of 25 mg/kg three times daily for 5 days. Diarrhoea occurred in 3 of 4 foals treated and of these one died during belated intravenous therapy for dehydration. Arteriography allowed for an in vivo assessment of the development and regression of lesions in infected-treated foals compared to the continued development of lesions in infected-untreated foals. The arteriographic findings were confirmed at necropsy.

Albendazole↗
PubMed1979

Ostertagiosis in captive bison in New York State: report of nine cases.

Type II ostertagiosis was found at necropsy in 9 American bison (Bison bison) from 3 farms in New York. Clinical signs included severe diarrhea, emaciation, unthrifty coats, anemia, and weakness. In severely affected animals, the macroscopic abomasal changes consisted of irregular thickening and edema of the mucosa, resulting in a pebbly or morocco-leather appearance. Microscopically, many gastric pits and glands were dilated, lined by hyperplastic epithelium, and contained nematode sections or debris. Parasites recovered included Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus lerouxi, Cooperia oncophora, Haemonchus contortus, Nematodirus helvetianus, Trichuris discolor, Setaria labiato-papillosa, Dictyocaulus viviparus, Hypoderma lineatum, and Sarcocystis sp. Nodules in the small and large intestine were attributed to Oesophagostomum sp. Trichostrongylus lerouxi, Trichuris discolor, and Nematodirus helvetianus are reported from bison for the first time.

Abomasum↗
PubMed1979

Transmission and control of Filaroides hirthi lungworm infection in dogs.

Transmission of Filaroides hirthi among cagemate pups was demonstrated to occur through the ingestion of first-stage larvae in recently passed feces. It was suggested that coprophagia is the principal mechanism of transmission of F hirthi and that transmission from brood bitches to their litters occurs by this mechanism during and after the fourth or fifth week of the nursing period. Medication of 15 infected brood bitches with two courses of albendazole at a dosage rate of 50 mg/kg of body weight twice each day for 5 days resulted in complete absence of F hirthi infection among all 21 of their progeny, whereas 16 of 19 progeny (84%) from 14 nontreated infected dams harbored F hirthi worms.

Animals↗
PubMed1978

Anthelmintic activity of albendazole against Filaroides hirthi lungworms in dogs.

Albendazole given at a dosage rate of 25 to 50 mg/kg twice daily for 5 days killed all but a small proportion and sterilized the few surviving Filaroides hirthi worms in artificially infected Beagle pups. Extensive tissue reaction around the dead worms persisted for an undetermined length of time. However, albendazole treatment of mature stock should prove useful in preventing transmission of F hirthi infection to their offspring and thus provide an efficient means of control.

Animals↗
PubMed1977

Patency and transmission of Filaroides hirthi infection.

Filaroides hirthi lungworm infection was diagnosed by the recovery of 1st-stage larvae from the faeces of dogs with heavy, artificially induced infections using zinc sulphate flotation. Diagnosis of low-grade natural infections was infrequently achieved. Zinc sulphate flotation was demonstrated to be about 100 times as efficient as the Baermann technique in concentrating F. hirthi larvae from dog faeces. Larvae recovered from faeces proved to be infective when fed to a pup and it was concluded that F. hirthi infection can be transmitted directly and immediately by fresh faecal contamination. Mongrel dogs of diverse ancestry were readily infected by feeding 1st-stage larvae from lung tissue. Thus, F. hirthi infection was shown not to be limited to the Beagle breed by biological restrictions. The observations that 1st-stage larvae pass through the alimentary tract on their way out of the body and that larvae are found in the mesenteric lymph nodes long after a single exposure to infection support the hypothesis that there is an autogenous re-infection of the host by a proportion of these larvae.

Animals↗
PubMed1977

Infection of weanling pigs with known numbers of Ascaris suum fourth stage larvae.

Nineteen weanling pigs were each infected per os with 200 fourth stage Ascaris serum larvae and were fed either a low protein or a high protein diet for 8 weeks. Worms expelled during the 8 weeks were recovered and all worms remaining in the gastrointestinal tract at slaughter were collected. Fifty-four percent of all worms were recovered at slaughter. Ten of the 19 animals maintained an infection for 8 weeks; the other 9 showed no signs of A. suum infection. A total of 377 worms were recovered. Average worm burdens were 37.7 worms per pig, 50.8 worms per low protein pig, and 30.8 worms per high protein pig. Times of and possible causes for expulsion are discussed. Procedure for infection of pigs is discussed in detail and possible improvements in technique are suggested.

Animals↗
PubMed1976

Biological controls in mixed trichostrongyle infections.

The parasite reaction phenotype of 80 lambs was determined with natural infection on pasture. These lambs were then assigned to outcome groups and randomized into treatment groups. Developing some simple but unusual analytical techniques it was possible to demonstrate that mixed natural infections of trichostrongyles with the chief biomass component Haemonchus contortus cayugensis protected against superinfections with 35000 infective larvae but protected against superinfections with 1000 infective larvae per day only within the limits characteristic of the enclosing barn ecosystem. The limits of the barn ecosystem were less constraining on more diathetic sheep than the natural pasture infection. Internal evidence from the experiment suggests that the interaction of sheep X pasture X infective trichostrongylid larvae constrains the parasite biomass in the host in more diathetic animals at significantly lower levels. Anaphylactoid 'self-cure' did not occur in this experiment but something like premunition certainly did.

Animals↗
PubMed1976

Naturally occurring cerebrospinal parelaphostronglylosis.

An isolated case and an outbreak of parelaphostrongylosis in goats are described. Signs included tetraparesis, hemiparesis, tetraplegia, spastic gait, scoliosis, vestibular strabismus, blindness, and death. Five cases were necropsied and nematodes were seen in the brain and spinal cord of four of these. Intact adult nematodes from two cases were identified as Parelaphostrongylus tenuis, the meningeal worm of white-tailed deer. Cerebrospinal fluid analysis from affected goats showed a moderately elevated protein content, evidence of hemorrhage, and mononuclear cell and eosinophil pleocytosis. Recoveries are recorded.

Animals↗
PubMed1976

Preliminary investigation of the life history of Filaroides hirthi Georgi and Anderson, 1975.

Filaroides hirthi lungworm infection increased as a function of age among 47, 9 to 32 week old Beagle pups at a commercial breeding establishment. Probit analysis of these data yielded an estimate of 50% infection was by age 17.4 +/- 3.7 weeks. This parasite and/or its associated lesions remained in at least 40% of infected Beagles at least 10 months after exposure to infection had ceased. Reinfection rendered improbable by the nature of the new environment, a laboratory animal colony. Repeated efforts have failed to demonstrate by the Baermann technique eggs or larvae of this parasite in the feces, bronchial mucus, or intact lung tissue of infected Beagles. All efforts to identify an intermediate or alternate definitive hosts have likewise proved unavailing. Piperazines, dichlorvos, thiabendazole, dithiazanine iodide, and levamisole appear to be without effect on the proportion of Beagles infected. The diet, which contained uncooked meat, was fed in a controlled experiment to 10 Beagles from an uninfected source without producing a single case of F. hirthi infection. Life cycles of other members of the superfamily Metastrongyloidea and possible explanations for the non-patency of F. hirthi infection are discussed.

Age Factors↗
PubMed1976

Analysis of the microfilarial periodicity of Dirofilaria immitis.

Microfilarial periodicity displayed by dogs infected with Dirofilaria immitis was analyzed using the methematical model proposed by Sasa and Tanaka (S.E. Asian J. Trop. Med. and Pub. Health 4, 1974, 518-536) except that Pearson's product-moment correlation test was substituted for their Chi-square analysis to estimate goodness of fit. Samples were drawn at 3 hour intervals for periods of 24 or 48 hours in a series of 10 studies conducted on 4 dogs. No significant differences were observed in microfilarial concentration between samples of venous and cutaneous capillary blood. Significant correlation of observed microfilarial densities with the values predicted by the model were observed in 7 of the 10 studies with r2 values ranging from 78.8 to 95.3%. The periodicity index ranged from 28.33 to 53.50 in these 7 studies and thus fell in the subperiodic category. The estimated hour of peak microfilarial density was not confined to the late afternoon as generally believed; for example, values of 04:00 and 22:00 hours were observed. Thus D. immitis microfilaremia cannot accurately be characterized either as diurnal or as nocturnal. Observation of the behavior of the experimental dogs led to an hypothesis that emotional and environmental stresses placed on the host may induce transients in the microfilarial density that may overwhelm or obscure the periodicity function.

Animals↗