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Biomedical subjects

A J Paul

Publications and source records attributed to A J Paul.

At least 19 recordsLinked to original sources
PubMed2001

Cleanability of soiled stainless steel as studied by atomic force microscopy and time of flight secondary ion mass spectrometry.

The hygienic status of food contact surfaces can deteriorate with wear. Effective cleaning regimes must remove any adsorbed organic material as well as microorganisms. Previous work has determined the extent of surface wear occurring on a stainless steel surface within the food industry, and we have reproduced representative samples in vitro. Two surface analytical techniques, atomic force microscopy and time of flight secondary ion mass spectrometry were combined with fluorescence microscopy to give detailed analysis of stainless steel surfaces fouled with starch and milk powder, then cleaned with water either by a spray or brushing method. It was found that the surface cleanability is affected by the cleaning regime and the surface roughness, not only the average vertical roughness but also by the shape of the surface defects, with sharp scratches more difficult to clean than wider surface defects. Spray cleaning with distilled water was found to be a selective method by preferentially removing proteinaceous material more easily than fatty acid ester material. The analytical techniques employed provided information on selective cleanability and surface topography at a hitherto unexplored level, and the information gained may be of value in the design and investigation of novel cleaning regimes and hygienic surfaces.

Detergents↗
PubMed2000

Safety of moxidectin in avermectin-sensitive collies.

OBJECTIVE: To evaluate the safety of moxidectin administration at doses of 30, 60, and 90 microg/kg of body weight (10, 20, and 30 times the manufacturer's recommended dose) in avermectin-sensitive Collies. ANIMALS: 24 Collies. PROCEDURE: Collies with mild to severe reactions to ivermectin challenge (120 mg/kg; 20 times the recommended dose for heartworm prevention) were used. Six replicates of 4 dogs each were formed on the basis of body weight and severity of reaction to ivermectin test dose. Within replicates, each dog was randomly allocated to treatment with oral administration of 30, 60, or 90 microg of moxidectin/kg or was given a comparable volume of placebo tablet formulation. Dogs were observed hourly for the first 8 hours and twice daily thereafter for 1 month for signs of toxicosis. RESULTS: Signs of toxicosis were not observed in any control group dog throughout the treatment observation period. Likewise, signs of toxicosis were not observed in any dog receiving moxidectin at 30, 60, or 90 microg/kg. CONCLUSIONS AND CLINICAL RELEVANCE: The moxidectin formulation used in the study reported here appears to have a wider margin of safety than ivermectin or milbemycin in avermectin-sensitive Collies.

Administration, Oral↗
PubMed1999

A comparison of the bioequivalence of 0.5% fenbendazole top dress pellets or 10% fenbendazole oral suspension against a spectrum of equine parasites.

A controlled test was conducted to assess the efficacy bioequivalence of a single dose of 0.5% fenbendazole (FBZ) top dress pellets to a 10% FBZ suspension formulation (Panacur suspension 10%, Hoechst Roussel Vet). Thirty horses with naturally-acquired parasite infections, in replicates of three, were used. Strongyle egg per gram counts were not significantly different (P>0.1) between groups pretreatment, but FBZ treated groups were significantly different from the control group post-treatment. At necropsy, which occurred seven to nine days post-treatment, two methods of nematode recovery were compared to assess whether a small aliquot can be used in a control test to determine efficacy against large as well as small strongyles. Both post mortem worm recovery techniques revealed similar efficacies of both formulations (>95%) against small and large strongyles, but large differences in the number of worms recovered. Six species of small strongyles comprised 96% of all the small strongyles recovered: Coronocyclus coronatus, Cylicocyclus insigne, Cylicostephanus longibursatus, Cylicocyclus brevicapsulatus, Cylicocyclus nassatus, and Cyathostomum catinatum. The results of this study demonstrated therapeutic bioequivalence between FBZ formulations and also the need to sample at least a 10% aliquot to accurately estimate number of large strongyles. No adverse reactions to treatment were detected.

Administration, Oral↗
PubMed1999

Persistent activity of doramectin and ivermectin against Ascaris suum in experimentally infected pigs.

A study was conducted to investigate the persistent nematocidal activity of two avermectins against experimentally-induced infections of Ascaris suum in swine. Seventy-two nematode-free cross-bred pigs of similar bodyweight were randomly allotted to nine treatment groups of eight pigs each. Eight of the groups were treated with injectable solutions containing 300 microg of doramectin/kg (IM) or 300 microg of ivermectin/kg (SC) either 0 (same day), 7, 14, or 21 days prior to an oral challenge of 50000 embryonated A. suum eggs. The ninth group (control) was challenged in parallel without any avermectin treatment. At 41 or 42 days after challenge, pigs were euthanatized and adult and larval stages of A. suum were collected from the gastrointestinal tract of each pig and counted. Both avermectins significantly (P < 0.0002) reduced nematode counts when given on the day of challenge (0 days prior), and the efficacy was 100% and 97.5% for doramectin and ivermectin, respectively. Doramectin given 7 days prior to challenge significantly (P < 0.0001) reduced nematode counts, and the efficacy was 98.4%. For all other avermectin-treatment groups, nematode counts were not significantly reduced compared to those in control pigs. These data indicated that anthelmintic activity of ivermectin against A. suum persisted for less than 7 days and the activity of doramectin persisted for more than 7, but less than 14 days.

Animals↗
PubMed1999

Treatment and control of gastrointestinal parasites.

Routine anthelmintic treatments are one of the most important components of an equine wellness program used by horse owners and veterinarians today. Thirteen different compounds are available in the United States in the treatment of gastrointestinal parasites, most of which are available over the counter. As a result, there is a decreased reliance on the veterinarian to perform routine tube dewormings. Therefore, the future of the veterinarian's role in the management of gastrointestinal parasites is likely to be in the consultation and design of parasite control programs. With this in mind, this article covers all of the equine anthelmintics and their clinical applications.

Animals↗
PubMed1998

The use of SIMS, XPS and in situ AFM to probe the acid catalysed hydrolysis of poly(orthoesters).

Due to poly(orthoesters) being susceptible to acid catalysed hydrolysis, these polymers have attracted considerable interest for the controlled delivery of therapeutic agents within biodegradable matrices. The pH-sensitivity of the poly (orthoesters) has lead to several drug delivery systems being developed, whose rate of drug release is predominantly controlled by the rate of polymer hydrolysis. This study reports on the use of X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and atomic force microscopy (AFM) in a multitechnique approach to probe the effect of acid catalysed hydrolysis at the interface of poly(orthoesters). The molecular specificity of SIMS was successfully employed, suggesting that the preferred mechanism for hydrolysis was via the cleavage of an exocyclic alkoxy bond in the 3,9,-diethylidene-2,4,8,10-tetraoxaspiro [5,5] undecane(DETOSU) unit. The resulting change in the surface chemical structure of the partially hydrolysed poly(orthoester) is such that it was not detectable by XPS analysis. Images acquired from an in situ AFM study of the hydrolysis ofa poly(orthoester), showed changes in the surface morphology, seen as the formation of pits, and an overall thinning of the polymer film. The use of SIMS, XPS and AFM has enabled changes in surface chemistry to be compared with changes in surface morphology. These complementary data, on the behaviour of the polymer during degradation have important implications for the further design of novel biodegradable materials.

Biocompatible Materials↗
PubMed1998

Cutaneous antimicrobial preparation prior to intravenous catheterization in healthy dogs: clinical, microbiological, and histopathological evaluation.

The purpose of this study was to determine the effects of a one-minute chlorhexidine gluconate skin preparation protocol prior to cephalic vein catheterization. Twenty-three healthy beagle dogs had one leg aseptically prepared and the opposite leg served as a control. Twenty-six- and 77-hour time groups were studied. Chlorhexidine-treated legs had significantly lower cutaneous bacterial counts than the control legs prior to catheter insertion and prior to catheter withdrawal for both time groups. Control legs developed significantly more dermatitis than the treated legs after 77 h. A one-minute preparation with 4% chlorhexidine gluconate was an effective method for sustained reduction of cutaneous bacterial counts at peripheral intravenous catheter insertion points in dogs. Increased cutaneous bacterial counts were associated with significantly more microscopic dermatitis in untreated legs after 77 h of catheterization.

Administration, Topical↗
PubMed1997

Investigation of the dissolution of the bioceramic hydroxyapatite in the presence of titanium ions using ToF-SIMS and XPS.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) analyses have been used to investigate the dissolution of hydroxyapatite in the presence of titanium chloride suggesting the substitution of titanium ions for calcium in the hydroxyapatite structure. The surface analytical data suggest that titanium was incorporated within the solid phase as titanium phosphate. Comparison of relative ion intensities in the ToF-SIMS spectra reveals changes in the composition of the surface chemistry of hydroxyapatite. These relative ion intensities show that the maximum surface uptake of titanium occurred at a solution concentration of 500 ppm titanium chloride for a time of incubation of 30 min. These data correlate with that obtained using XPS highlighting the semi-quantitative information which ToF-SIMS can provide.

Biocompatible Materials↗
PubMed1997

Clinical trial of moxidectin oral gel in horses.

A clinical trial carried out over 98 days was done to evaluate treatment of horses with moxidectin gel for efficacy as measured by (1) reduction in the production of parasite ova post treatment, (2) a comparison of the posttreatment parasite egg count suppression of moxidectin to ivermectin, and (3) assessment of the field safety, animal acceptance of the moxidectin formulation, and the utility of the moxidectin delivery device. One hundred and fifty Standardbred horses with naturally acquired parasite infections were used in the study. Moxidectin had more prolonged and greater suppressive influence than did ivermectin on reappearance and magnitude of strongyle egg counts post treatment. Differences were not observed between the capability of ivermectin or moxidectin to reduce and suppress low Parascaris equorum egg counts. Adverse reactions to treatments were not observed, and the utility of the moxidectin delivery syringe and animal acceptance of moxidectin treatment were satisfactory.

Administration, Oral↗
PubMed1996

Impact of an orally administered insect growth regulator (lufenuron) on flea infestations of dogs in a controlled simulated home environment.

OBJECTIVE: To evaluate the ability of lufenuron to control cat flea (Ctenocephalides felis felis) populations on dogs under conditions simulating a naturally infested home environment. DESIGN: 2 treatment and 2 control groups of dogs. Treated dogs received lufenuron in tablet form monthly, and controls received excipient. Dogs had unrestricted access to indoor (carpeted) and outdoor (grassy) environments in which self-propagating flea populations had been established. ANIMALS: 17 adult female Beagles. PROCEDURE: Dogs were monitored for 77 days after initial infestation with fleas and 70 days after initial treatment. Efficacy of the drug was calculated on the basis of absolute reduction in flea counts and as a percentage of control. RESULTS: Lufenuron administration caused a statistically significant (P < 0.05) reduction in flea burdens in treated dogs, compared with controls. Initiation of treatment 7 days after infestation resulted in 75% control of F1-generation and 97% control of F2-generation fleas over a 70-day posttreatment period. CONCLUSIONS: Lufenuron was highly effective in reducing flea populations on dogs. The time required for control will vary with the duration (generation time) of the flea reproductive cycle and, hence, the geographic area in which the product will be used. The experimental results are most relevant to use of the product for control of an existing flea population in the Midwest.

Administration, Oral↗
PubMed1995

Controlled efficacy study of the bioequivalence of Strongid C and generic pyrantel tartrate in horses.

The bioequivalence of Strongid C and generic pyrantel tartrate was determined in a controlled study using 30 horses with naturally acquired endoparasitic infections. Three horses were randomly allocated to each of ten replicates based on quantitative nematode and ascarid egg counts and fecal larvae culture results. Horses within each replicate were randomly assigned to one of three treatment groups. Horses in Treatment Group 1 received only oats; horses in Treatment Group 2 received generic pyrantel tartrate pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats; horses in Treatment Group 3 were fed Strongid C pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats. Horses were treated daily for a 30 day continuous treatment period. At the termination of the study the horses were necropsied and endoparasites recovered, identified, and enumerated. In all instances, no significant difference (P > 0.05) in mean numbers of parasites recovered existed between horses treated with generic pyrantel tartrate and Strongid C. Numbers of gastrointestinal parasites recovered from horses treated with generic pyrantel tartrate or Strongid C were shown to be significantly different (P < 0.05) from numbers of gastrointestinal parasites recovered from non-treated controls for the large strongyles (Strongylus vulgaris, S. edentatus, and Triodontophorus spp.), small strongyles (Cyathostomum spp., Cylicocyclus spp., and Cylicostephanus spp.) and fourth-stage Parascaris equorum. Numbers of adult P. equorum recovered from horses treated with Strongid C were also significantly different (P < 0.05) from those from non-treated controls. Numbers of adult P. equorum recovered from horses treated with generic pyrantel tartrate were not significantly different (P = 0.0761) from those from non-treated controls. The determination of bioequivalence was based upon the 95% confidence interval of the difference between the mean number of parasites recovered from horses treated with generic pyrantel tartrate and the mean number of parasites recovered from horses treated with Strongid C. For all instances in which the numbers of parasites recovered from horses treated with either Strongid C or generic pyrantel tartrate were significantly different from the numbers of parasites recovered from non-treated controls, bioequivalence was demonstrated.

Animal Husbandry↗
PubMed1991

Evaluation of the safety of ivermectin administered in a beef-based formulation to ivermectin-sensitive Collies.

Twenty-four Collies sensitive to the toxic effects of ivermectin, when administered at high dosages, were studied to evaluate the effects of repeated monthly treatment with an ivermectin beef-based formulation at amounts up to 10 times the dosage recommended for heartworm prevention in dogs. Collies were treated 3 times at 30-day intervals at rates of 12, 36, or 60 micrograms of ivermectin/kg of body weight, or with vehicle. Complete physical and neurologic examinations were performed on all dogs prior to the first treatment and after the final treatment. Clinical observations and ivermectin reaction scores were recorded daily for each dog throughout the study. Clinical or neurologic signs characteristic of ivermectin toxicosis were not observed for any dog during the study. Single episodes of vomiting were recorded for 2 vehicle-treated dogs and 2 dogs treated with ivermectin at 12 micrograms/kg from 6 to 21 days after treatment. At the end of the study, all dogs were challenge-exposed with ivermectin at 120 micrograms/kg to reconfirm their sensitivity to this class of compounds. All dogs developed signs typical of ivermectin toxicosis during the subsequent 48- to 72-hour period. Results of this study demonstrated that ivermectin can be administered repeatedly without adverse effects at rates up to 60 micrograms/kg (10 times the recommended use level) to Collies known to be sensitive to this drug.

Animals↗
PubMed1991

Efficacy of ivermectin chewable tablets and two new ivermectin tablet formulations against Dirofilaria immitis larvae in dogs.

One hundred four heartworm-free Beagles less than 1 year old were studied to determine the efficacy of ivermectin chewable tablets and of 2 other ivermectin tablet formulations against heartworm larvae. At 30 days after SC inoculation of dogs with infective Dirofilaria immitis larvae, all ivermectin formulations were given orally at dosage of 6 micrograms/kg of body weight. The ivermectin chewable tablets also were given orally at dosage of 2 and 6 micrograms/kg at 30 and 45 days, respectively, after injection of larvae. Replicates of 6 or 8 dogs in each study were formed on the basis of gender and body weight and, within replicates, were randomly allocated to treatment groups. At 30 days after injection of larvae, the additional dogs (in replicates of 8) were assigned to the control group and to the group given ivermectin chewable tablets at dosage of 6 micrograms/kg. All dogs were housed individually. Necropsy was performed approximately 5 or 6 months after larvae were administered. In both trials, all control dogs had heartworms at necropsy (University of Illinois--geometric mean, 35.0; Florida--geometric mean, 26.1). In both trials, the ivermectin chewable tablet (6 micrograms/kg) and both tablet formulations (6 micrograms/kg) given at 30 days after larval injection, and the chewable formulation (6 micrograms/kg) given at 45 days after larval injection were 100% effective (P less than 0.01) in preventing development of induced infection with D immitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Assessment of toxicosis induced by high-dose administration of milbemycin oxime in collies.

Fifteen Collies, previously having mild reactions to ivermectin challenge (120 micrograms/kg of body weight; 20 times the recommended dosage level), were studied to evaluate the effects of milbemycin oxime administration at 5 and 10 mg/kg (10 and 20 times the manufacturer's recommended dosage). Five replicates, comprising 3 dogs each, were formed on the basis of body weight. Within replicates, each dog was randomly allocated to treatment with 5 or 10 mg of milbemycin/kg or served as a untreated control. Dogs were examined repeatedly for signs of toxicosis for 4 days after treatment and daily thereafter. Two of 5 dogs treated at 5 mg/kg (10x) developed signs of mild depression on the day of treatment, but were normal 24 hours after treatment. All 5 dogs treated at 10 mg/kg (20x) developed signs of mild depression and ataxia by 6 hours. Signs persisted for 24 hours in 3 dogs. Two of these dogs also had mydriasis, whereas 3 salivated excessively. All dogs recovered completely by day 2 after treatment. The results of this study demonstrated that Collies sensitive to the effects of 120 micrograms of ivermectin (20x)/kg show similar sensitivity to the effects of milbemycin oxine administered at 10 mg/kg (20x). We conclude that ivermectin and milbemycin commercial formulations have similar margins of safety and that milbemycin toxicosis appears to be dose-dependent in Collies with a demonstrated sensitivity to ivermectin.

Animals↗
PubMed1989

Ivermectin plasma concentrations in collies sensitive to ivermectin-induced toxicosis.

Five Collies sensitive to toxic effects of ivermectin and 7 nonsensitive Collies were given 100 micrograms of ivermectin/kg of body weight, PO. Blood samples were collected from each dog before treatment; at posttreatment hours 1, 2, 3.5, 5, and 8; and at posttreatment days 1, 2, 4, 7, 14, and 21. Each sample was assayed for ivermectin concentration, and statistical analyses were performed on the resulting plasma concentration data to determine differences in absorption and clearance of drugs between the 2 groups. Variables measured were area under the curve (using the trapezoidal rule), peak plasma concentration, and the time to peak concentration. Differences between sensitive and nonsensitive Collies for variables analyzed were not significant (P greater than 0.05).

Absorption↗
PubMed1988

Two-dimensional echocardiography for diagnosis of dirofilariasis in nine dogs.

Two-dimensional echocardiography (real-time ultrasonography) of the heart was used to detect adult Dirofilaria immitis in the right ventricle and atrium of a 2-year-old Labrador Retriever with occult heartworm disease and in 8 microfilaremic dogs. Adult worms were easily identified as parallel echogenic lines separated by a hypoechoic region. Images of worms fixed in formalin after recovery from dogs with experimentally induced heartworm infection had an identical appearance. The sensitivity of this imaging procedure was tested on the 8 dogs with naturally acquired infection, and worms were observed in the right ventricle of 7 of the dogs. Two-dimensional echocardiography appears to be a sensitive noninvasive procedure, which can be used in combination with thoracic radiography and serotests to improve accuracy of diagnosis of canine occult heartworm disease.

Animals↗
PubMed1988

Environmental contamination by eggs of Toxocara species.

A study was conducted to determine the level of contamination with Toxocara spp. eggs in parks and playgrounds in several central Illinois communities. A total of 135 composite 50-g soil samples were collected from 23 parks and public places in three cities in central Illinois. Of these soil samples, 22 (16.3%) contained from one to thirteen Toxocara spp. eggs. A total of 40 fecal samples were collected from the same parks. Toxocara spp. eggs were found in two (5%) of the samples.

Animals↗