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Biomedical subjects

H W Taylor

Publications and source records attributed to H W Taylor.

At least 37 records · Page 2Linked to original sources
PubMed1996

Differences in the kinetics of T cell accumulations in C3H/HeN (Bcg-resistant) and C57BL/6 (Bcg-susceptible) mice infected with Mycobacterium paratuberculosis.

The accumulation of various T cell subsets in Bcg-susceptible (C57BL/6) and- resistant (C3H/HeN) strains of mice were compared following an intraperitoneal infection with Mycobacterium paratuberculosis. Groups of mice from both strains were killed at 3, 5, 10, 15, 30, and 150 days after infection and lymphocytes were harvested from the peritoneal exudate cells (PEC), spleen, intestinal epithelial lymphocytes (IEL), lamina propria lymphocytes (LPL), Peyer's patches, and mesenteric lymph node (MLN) and labelled with monoclonal antibodies to CD3, CD4, CD8, gamma delta TCR, CD25, and CD44 for flow cytometric analysis. Uninfected C3H/HeN mice had higher proportions of CD4+ cells in the spleen, MLN, LPL, IEL, and Peyer's patches, while uninfected C57BL/6 mice had higher proportions of CD8+ and/or gamma delta T cells. Significant increases in accumulation of CD8+ and gamma delta T cells were detected in the peritoneum and other tissues in both strains of mice after infection. Higher CD4/CD8 ratios were observed in most lymphoid tissues of C3H/HeN mice, while increased proportions of CD8+ and/or gamma delta T cells were present in C57BL/6 mice. These results indicate that significant differences in T cell profiles exist between these two strains of mice, both inherently and in response to infection with M. paratuberculosis. Innately lower levels of CD4+ cells and/or higher percentages of CD8+ and gamma delta T cells may play a role in the increased suspectibility of C57BL/6 mice to infection with M. paratuberculosis.

Animals↗
PubMed1996

Comparison of moxidectin oral gel and ivermectin oral paste against a spectrum of internal parasites of ponies with special attention to encysted cyathostome larvae.

Two dosages of moxidectin oral gel were evaluated and compared to a therapeutic dose of ivermectin oral paste in the control of a spectrum of gastrointestinal parasites of ponies naturally infected in southern Louisiana or Mississippi. Thirty-two mixed-breed ponies ranging in age from one to 21 years were used in this controlled test. Eight weeks prior to the experiment, ponies grazing on contaminated pasture were moved to a paddock and fed a pelleted ration, thus reducing or eliminating the potential for additional infection and ensuring the existence of a population of encysted larvae. Ponies were then allocated to replicates of four animals based on values of fecal strongyle egg counts and percent strongyle larvae composition determined from Baermann sedimentations of fecal cultures. Members of replicates were allocated to one of four treatment groups: moxidectin oral gel administered at 300 micrograms kg-1 body weight, moxidectin oral gel at 400 micrograms kg-1, the oral gel vehicle as negative control, and ivermectin oral paste at 200 micrograms kg-1. Prior to treatment, ponies were confined in pairs to covered concrete runs by treatment group. Two weeks following treatment, necropsy examinations of all animals were performed. Parasites were recovered from the lumen of the stomach, the intestinal tract, the cranial mesenteric artery and its major branches, the peritoneal body wall and from pepsin digests of mucosal scrapings taken from the cecum and large colon. Encysted cyathostome larval burdens were also compared using mural transillumination of segments of the large colon for visualization of the encysted forms. Control ponies were not uniformly infected with the spectrum of parasites; however, moxidectin, at either dosage, compared favorably with ivermectin in the control of the adults of Strongylus vulgaris, Strongylus edentatus, Triodontophorus spp., Oesophagodontus robustus, Trichostrongylus axei, Oxyuris equi, Parascaris equorum, Habronema muscae, as well as both the adult and larval Cyathostominae recovered from the lumen. Moxidectin also appears as efficacious as ivermectin against migrating large strongyle larvae at the two weeks post-treatment evaluation. Moxidectin demonstrated a trend towards greater efficacy against encysted cyathostome larvae than a therapeutic dosage of ivermectin, but this difference was not statistically significant. Moxidectin was less effective than ivermectin against Gasterophilus intestinalis and was equally ineffective as ivermectin against Anoplocephala perfoliata.

Administration, Oral↗
PubMed1996

Lysosomal storage disease in an emu (Dromaius novaehollandiae).

Lysosomal storage disease involving the brain, spinal cord, liver, and spleen was discovered in a 6-month-old male emu (Dromaius novaehollandiae). The diagnosis was based on light and electron microscopic studies and histochemical staining characteristics. This is the first case of lysosomal storage disease reported in a ratite.

Animals↗
PubMed1996

Primary extranodal lymphosarcoma of the trachea in a cat.

A primary extranodal lymphosarcoma causing recurrent-episodes of dyspnea and exercise intolerance is described in a 13-year-old cat. The affected segment of the tracheal wall was markedly thickened due to transmural infiltration of monomorphic neoplastic lymphoid cells and the lumen was severely compressed. The diagnosis was based on light microscopic studies, positive immunostaining for feline IgA, and special stains.

Animals↗
PubMed1995

Dose titration of moxidectin oral gel against gastrointestinal parasites of ponies.

Moxidectin was tested as an oral gel formulation during a controlled test performed to evaluate dosages against equine gastrointestinal parasites. Four groups of ten ponies were used. Ponies ranged from 1 to 20 years of age and were naturally infected in southern Louisiana or Mississippi. Fecal exams and fecal cultures were performed on all ponies to determine the strongyle egg counts and the percent distributions of large and small strongyles. Following these determinations, ponies were allocated to replicates of four ponies to provide an even distribution of strongyle infection, age, weight and gender. Members of each replicate were then randomly assigned to one of four treatment groups. The doses tested were 300, 400 and 500 micrograms kg-1 body weight. The oral gel vehicle alone served as control. Treatments were administered behind the tongue and the ponies were observed continuously for 4 h for any adverse reactions; thereafter, ponies were observed at least twice daily. Necropsy examinations were performed 14 days post-treatment for the recovery and identification of any parasites present. Moxidectin, at all doses tested, was 100% efficacious against adults of Strongylus vulgaris, Strongylus edentatus, Triodontophorus spp. and 22 species of small strongyles. Moxidectin was also 100% efficacious against larvae of Strongylus edentatus and Oxyuris equi, greater than 94% efficacious against Strongylus vulgaris larvae and Oxyuris equi adults at 14 days post-treatment. Moxidectin proved highly efficacious against luminal small strongyle larvae (> 99.9% against L4 and > 92% against L3) and moxidectin demonstrated some efficacy against encysted small strongyle larvae as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Dose titration of moxidectin oral gel against migrating Strongylus vulgaris and Parascaris equorum larvae in pony foals.

Moxidectin was tested for efficacy in ponies against experimental infections of 56 day Strongylus vulgaris larvae and 11 day Parascaris equorum larvae. Three dosages of moxidectin were tested: 300 micrograms per kg live body weight, 400 micrograms per kg, and 500 micrograms per kg, and the vehicle served as control. Ponies were first infected with 600 S. vulgaris third-stage larvae (L3) on Experiment Day 0 and then with 3000 embryonated P. equorum eggs on Day 45. Moxidectin treatments were administered on Day 56 and necropsy examinations were performed on Day 91. Strongylus vulgaris fourth-stage (L4) and fifth-stage (L5) larvae were recovered at necropsy from the control ponies, in dissections of the cranial mesenteric artery and its branches (L4 and L5), and recovered from nodules in the wall of the cecum and ventral colon (L5). Parascaris equorum larvae were recovered from the small intestine of control ponies. Moxidectin was highly efficacious against S. vulgaris L4 and L5 at all three doses tested (99.6-100%), and appeared to be equally efficacious against P. equorum larvae (100%); however, control ponies had low levels of P. equorum infections compared to previous experimental infections performed using identical methods. This suggests that the prior S. vulgaris infection on Day 0 may have influenced the subsequent experimental P. equorum infection on Day 45 and contributed to the lower recovery.

Administration, Topical↗
PubMed1995

Comparison of the resistance of C57BL/6 and C3H/He mice to infection with Mycobacterium paratuberculosis.

Susceptibility of C57BL/6 (Bcgs) and C3H/HeN (Bcgr) mice to an intraperitoneal infection with Mycobacterium paratuberculosis strain 19698 was compared (by histopathology and the number of mycobacteria isolated from the spleen). Mycobacterial counts from the spleen of Bcgr mice progressively decreased over the course of infection but remained unchanged in Bcgs mice. Granulomatous lesions and acid-fast bacteria were consistently present in the liver and lymph nodes of Bcgs mice, whereas lesions were transient or absent in Bcgr mice. These results indicate that Bcgr mice are inherently resistant to M. paratuberculosis, whereas Bcgs mice are inherently susceptible. These differences may prove useful in elucidating the mechanisms of resistance and susceptibility to paratuberculosis and other mycobacterial infections.

Animals↗
PubMed1995

Histopathology of C57BL/6 mice inoculated orally with Mycobacterium paratuberculosis.

The susceptibility of C57BL/6 mice to oral inoculation with Myobacterium paratuberculosis was evaluated histopathologically. Granulomatous lesions containing acid-fast bacteria developed in the mesenteric lymph nodes in over 50% of the mice by 11 months after inoculation. The results suggest that C57BL/6 mice may be useful for studying infection, pathogenesis, and other aspects of paratuberculosis.

Administration, Oral↗
PubMed1995

Helix-stabilizing agent, CC-1065, enhances suppression of translation by an antisense oligodeoxynucleotide.

The antitumor antibiotic CC-1065 is known to bind at selected sequences in the minor groove of duplex nucleic acids and to hyperstabilize the duplexes against thermal melting. These properties suggested that CC-1065 may enhance translation inhibition by antisense oligonucleotides directed against a specific mRNA. A 585 bp mRNA transcript containing the equine infectious anemia virus (EIAV) S2 gene and a portion of the env gene was prepared. Also, a complementary 20 mer antisense oligodeoxynucleotide (5'-TGTTGGGTAATAGG-GGTTGA-3') was prepared against a target sequence in the mRNA located near the translational initiation sites of the overlapping S2 and env genes. The center of the target sequence had an expected CC-1065 recognition sequence (5'-UAUUA-3'). Translation in the presence of CC-1065 and antisense was markedly suppressed compared with that of antisense alone. Addition of a sense 20 mer strand, with or without CC-1065, had little or no effect on translation. CC-1065 and related compounds may be useful as ligands for enhancing the stability of sense-antisense duplexes and for promoting the inhibition of translation by antisense oligonucleotides.

Antibiotics, Antineoplastic↗
PubMed1994

Experimental immunization of ponies with Strongylus vulgaris radiation-attenuated larvae or crude soluble somatic extracts from larval or adult stages.

Protection from Strongylus vulgaris infection through immunization with radiation-attenuated third-stage larvae (L3) or crude soluble homogenates from larval or adult stages was examined. Yearling ponies raised parasite-free were divided into 3 immunization groups: radiation-attenuated L3; soluble adult somatic extracts; larval somatic extracts with excretory/secretory products (E/S) from in vitro culture; and 1 medium control group. Ponies were immunized twice; attenuated larvae were administered orally and somatic extracts or controls injected intramuscularly with adjuvant. Approximately 6 wk following the second immunization, all ponies were challenged. Necrospy examinations were performed 6 wk following challenge. Irradiated larvae recipients had the fewest postchallenge clinical signs and lesions and were 91% protected from infection determined by larval recoveries from arterial dissections. Soluble antigen recipients and controls had similar larval recoveries and thus equal susceptibility to challenge. Soluble antigen recipients had more severe clinical signs and lesions than controls, suggesting that parenteral immunization exacerbated postchallenge inflammatory responses. Protection by immunization with irradiated larvae was associated with an anamnestic eosinophilia and postimmunization antibody recognition of S. vulgaris L3 surface antigens. Histologic staining of eosinophils within tissues of this group suggested that this immunization induced a cytophilic antibody response that facilitated degranulation.

Analysis of Variance↗
PubMed1993

Expression of p53 in colorectal cancer and dysplasia complicating ulcerative colitis.

An immunohistochemical method using Pab1801, a monoclonal antibody specific to the human p53 protein, was applied to detect p53 expression in colorectal cancer and dysplasia complicating ulcerative colitis. Of 20 tissue samples with dysplasia, six showed positive immunoreactivity. Archival paraffin-embedded tissue blocks from 21 colitic cancers were analysed; 11 showed positive immunoreactivity, compared with ten of 21 samples from matched sporadic colorectal cancers (P not significant). Previous data suggesting that colorectal carcinoma complicating ulcerative colitis has a reduced frequency of c-Ki-ras mutation compared with sporadic cancer have led to the hypothesis that different genetic lesions underlie colitic and sporadic colorectal carcinoma. The present results suggest that this is not the case with regard to p53 gene alterations.

Adult↗
PubMed1993

Evaluation of ivermectin at an elevated dose against encysted equine cyathostome larvae.

The efficacy of a high dose of ivermectin (1.0 mg per kg Eqvalan liquid drench) on encysted cyathostomes was tested in a controlled study using 12 adult ponies with naturally acquired cyathostome infections. Six treated ponies and six non-treated controls were held in separate stalls for a period of 5 weeks. Cyathostome burdens, which included lumenal larvae, adults and encysted larvae, were determined at necropsy. The viability of encysted larvae, based on morphologic integrity, was assessed by observation of mural transillumination and by the histologic appearance of 12 larvae per pony. Efficacy against adult cyathostomes was 99.9%. Lumenal cyathostome larval numbers were reduced by 87%. Numbers of encysted cyathostome larvae, identified by transillumination of the large intestine, were reduced by 35%. However, this reduction was not statistically significant (P > 0.05) and differences in viability of encysted larvae were not observed. The data strongly indicated that ivermectin has little demonstrable effect on encysted equine cyathostomes.

Animals↗
PubMed1993

Comparison of the post-Chernobyl 137Cs contamination of mushrooms from eastern Europe, Sweden, and North America.

A comparison was made of 134Cs and 137Cs contamination in fungi from eastern Europe and eastern North America. Mean activities of 25 Ukrainian, 6 Swedish, and 10 North American collections were 4,660, 9,750, and 205 Bq/kg (dry weight), respectively. Additional measurements were made on samples from the Moscow, southern Belarus, and Yugoslavia/Bulgaria regions. Activity values were found to vary by several orders of magnitude within all geographic areas, even for the same mushroom species. Significantly higher specific activities were observed in mycorrhizal species than in saprophytic and parasitic fungi. Unfortunately, many of the European mycorrhizal species considered as prized edibles contained unacceptably high levels of 137Cs (> 1,000 Bq/kg [dry weight]) and should be used sparingly as food. By contrast, no mushrooms collected in Ontario or northern Michigan exceeded 1,000 Bq of 137Cs per kg (dry weight). The excessive 137Cs contamination was evident in mushrooms from areas that had substantial fallout from the 1986 accident in reactor 4 at the Chernobyl nuclear power station. However, observations suggest that about 20% of the 137Cs in eastern Europe (Moscow area, Belarus, and Ukraine) is of non-Chernobyl origin.

Air Pollution, Radioactive↗