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Biomedical subjects

D J Donovan

Publications and source records attributed to D J Donovan.

8 recordsLinked to original sources
PubMed1990

Anticoccidial effect of monensin against Eimeria mitis and Eimeria dispersa.

Four chick and five poult trials were conducted in order to investigate the anticoccidial efficacy of monensin against Eimeria mitis in chickens and Eimeria dispersa in turkeys. The chicks were fed a basal diet with either 0 or 100 ppm of monensin. The poults were fed a basal diet with either 0 or 60 ppm of monensin. Two days after the initiation of each experiment, the chicks and poults were crop-intubated with oocysts of E. mitis and E. dispersa, respectively. A group was also included that was not infected and not medicated. Growth and feed intake were recorded. At 6 or 7 days postinoculation, the birds were killed by cervical dislocation and were scored for the incidence and severity of intestinal abnormalities. The Eimeria mitis infection reduced (P less than .01) gain and the feed:gain ratio, compared with uninfected birds; the E. dispersa infection only reduced (P less than .05) gain. Although well-defined, discrete lesions were not observed, marked intestinal abnormalities were noted in birds infected with either E. mitis or E. dispersa. Also, the infected, unmedicated birds had increased (P less than .01) intestinal scores compared with uninfected birds or those with infection but treated with monensin. Monensin eliminated the reduction in gain and feed efficiency seen in the infected birds. The infected birds fed monensin had intestinal scores, gain, and feed:gain ratios similar (P greater than .10) to those for the birds that were not infected and that did not receive medication.

Animals↗
PubMed1989

Effect of narasin and roxarsone combinations on Eimeria tenella infections in floor pen-raised broilers.

A series of four floor pen trials was conducted to evaluate the effects of narasin and roxarsone, both alone and in combination, on their capacity to control severe Eimeria tenella infections in broilers. Three levels of narasin (0, 60, and 80 ppm) were fed to chickens receiving either 0, 25, or 50 ppm roxarsone in a factorial design. Cecal coccidiosis was induced by seeding the litter with ionophore-tolerant and ionophore-sensitive strains of E. tenella. After 8 days, 10 birds/pen were killed and their cecal lesions scored. Performance (body weight and feed consumption) and mortality were measured at the termination of the trials. Narasin reduced the severity of cecal coccidiosis as measured by a reduction in cecal lesions and an improvement in bird performance. Roxarsone also reduced cecal lesion scores. The highest level of roxarsone (50 ppm) in combination with 60 or 80 ppm narasin produced additive responses in the control of E. tenella infections. Maximum performance was obtained when narasin alone was fed at 80 ppm; drug combinations improved performance when compared with that of nontreated or roxarsone only-medicated groups.

Animals↗
PubMed1988

Randomized surgical adjuvant trial of interferon alfa-n1 in recurrent papillomatosis.

Sixty-six patients with recurrent respiratory papillomatosis of juvenile onset were treated for six months with interferon alfa-n1 (Wellferon) in a randomized crossover trial. Half received interferon alfa-n1 intramuscularly at a dosage of 5 megaunits per square meter daily for 28 days and then thrice weekly for five months, followed by six months of observation. The other half were observed for six months and then treated. Operations were performed every two months to assess disease extent by a scale developed for this purpose. The score for the patients during the first observation period was stable. There was a statistically significant lowering of score in patients receiving interferon alfa-n1 during both periods of drug administration. Eight of 57 patients with assessable airway disease achieved complete remission, as did one additional patient with disease limited to the nasopharynx. No patients achieved complete remission during six months of observation alone. This difference was statistically significant. Patients without tracheostomy were significantly more likely to achieve remission than those with a tracheostomy. The patients who were observed after discontinuation of the drug therapy showed a significant rise in score within four months. Symptoms of toxicity included transient fever, fatigue, nausea, and headache. Elevations in serum aspartate aminotransferase levels occurred in 64% of the patients. There was an inverse correlation between age and the ability to tolerate the medication. The dose studied may be close to the maximum tolerated dose. It appears that interferon alfa-n1 as an adjuvant to routine surgical management is effective in slowing the growth of respiratory papillomas.

Clinical Trials as Topic↗
PubMed1975

Comparative hemodynamic consequences of inflation hold, PEEP, and interrupted PEEP: an experimental study in normal dogs.

Cardiac output and airway, intrathoracic, arterial, pulmonary artery, left atrial, and central venous pressures were studied in 8 mongrel dogs. They were anesthetized and ventilated with (1) inflation hold of various duration, (2) continuous positive end-expiratory pressure and one breath off). The results indicate a minimal decrease in cardiac output (of approximately 5 per cent) with inflation hold. Diminished cardiac output was noted with increasing levels of continuous PEEP. The severity of the decrease in cardiac output wasproportional to the airway pressure. The higher levels (20 cm H2O) OF PEEP were associated with profound decreases. Utilization of a technique of interrupted PEEP substantially reduced the adverse hemodynamic effects in the dog.

Animals↗
PubMed1975

Carcinogen chemistry. I. Reactions of protonated dialkylnitrosamines leading to alkylating and aminoalkylating agents of potential metabolic significance.

Three distinct modes of protolytic dialkylnitrosamine fragmentation were observed when we followed the time dependence of the nuclear magnetic resonance (NMR) spectra of seven nitrosamines in superacid solution: 1) In equimolar HSO3F: SbF5 ("magic acid"), dimethylnitrosamine was cleaved to the protonated Schiff base of formaldehyde and methylamine, and diethylnitrosamine was similarly converted to the protonated acetaldehydeethylamine Schiff base.2) By contrast, of the five dipropyl-and dibutylnitrosamines were studied, all cleaved nonoxidatively under these conditions (with loss of nitrogen gas) to the corresponding propyl or butyl cations. The carbocations thus produced underwent condensation and fragmentation to form the tert-butyl cation as the principal product ultimately observable by NMR. 3) Thethird fragmentation mechanism, which involved denitrosation to the dialkylammonium ion, was observed only as a minor pathway in the sulfuric or fluorosulfuric acid protolysis of dimethylnitrosamine. The mechanisms that are postulated for these cleavage reactions, if functioning in vivo, could account for several metabolic observations that have proved difficult to reconcile with previous conceptions of nitrosamine metabolism.

Alkylating Agents↗