Effects of dopaminergic drugs on inflammatory bowel disease induced with 2,4-dinitrofluorbenzene in BALB/c mice.

The aim of the study was to demonstrate the effects of dopaminergic drugs on 2,4-dinitrofluorbenzene (DNFB) induced experimental inflammatory bowel disease (IBD) in previously sensitized BALB/c mice. The number and extent of ulcerations and erosions, the intensity of haemorrhages, oedema, and accumulation of neutrophils and eosinophils within colonic lamina propria and submucosa were scored and statistically evaluated. The 180 BALB/c mice, were allocated into three equal groups. The mice in the first experimental group were treated with domperidone (DP), a peripheral dopamine (DA) antagonist. The mice from the second experimental group were treated with bromocriptine (BC), a dopamine agonist. The mice from the control group were treated with an equivalent volume of normal saline in the same manner. Ten animals from each group were killed on days 1, 2, 3, 5 and 10, subsequent to the challenge enema of DNFB solution. Gross and microscopic examination of the colon was performed. Treatment with BC resulted in clinical improvement and decreased mortality rate by 2 of 60 (3%), while domperidone treatment increased mortality rate to 12 of 60 (20%) compared with the controls [4 of 60 (6%)]. The analysis of the microscopic lesions indicated that the beneficial effects of BC were the result of maintenance of vascular integrity.

Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone.

OBJECTIVE: To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs. ANIMALS: 22 healthy Beagles. PROCEDURE: All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure. RESULTS: Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions. CONCLUSIONS AND CLINICAL RELEVANCE: Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.

The isolation and sequence of canine interleukin-8 receptor.

A cDNA corresponding to canine IL-8 receptor has been cloned and sequenced. The cDNA was synthesized using RT-PCR, with oligonucleotide primers designed from conserved regions of published IL-8 receptors. The 5'-end was cloned by 5'-RACE and the 3'-end was cloned by 3'-RACE. The cDNA encodes a predicted full length IL-8r protein of 356 amino acids. At the nucleic acid level, the canine cDNA shows 83.9%, 82.4%/78.8%, 81.5%/78%, 81.4%/77.7%, 77.8% and 77.3%/71.9% identity to published sequences of bovine, human, gorilla, rabbit, mouse and rat IL8RB/IL8RA, respectively. The derived protein from the cDNA sequences shows 75.3%/70.3%, 75.3%/70.1%, 74.8%/69.4%, 70%/59%, and 69.7% identity to that of human, rabbit, gorilla, rat and mouse IL8RB/IL8RA homolog.

Experimental infection of the human granulocytic ehrlichiosis agent in horses.

Human blood collected from two patients from Westchester County, New York with human granulocytic ehrlichia (HGE) infection was inoculated into two ponies. Inoculated ponies developed clinical signs similar to a previous report (Madigan et al., 1995). Histopathological changes involved follicular hyperplasia of lymphoid tissues. HGE DNA was detected by PCR in muscle, fascia, peritoneum, and adrenal gland after the ponies produced a high level of antibodies to HGE. We suggest that HGE may reside in poorly vascularized connective tissues, where the antibodies may have some difficulties to penetrate, resulting in persistent infection. Since HGE and E. equi cause very similar diseases in both humans and horses, they may be the same organism with minor genetic differences.

Detection of human granulocytic ehrlichiosis agent and Borrelia burgdorferi in ticks by polymerase chain reaction.

Adult ixodid ticks were collected from Westchester County, New York, and Ipswich, Massachusetts, to determine the presence of infection with a human granulocytic ehrlichiosis (HGE) agent by using the polymerase chain reaction (PCR). The presence of Borrelia burgdorferi in ticks collected from New York was also determined by PCR. Of the 229 ticks from New York and 47 ticks from Massachusetts, 9% (22/229) and 25% (12/47) of ticks contained HGE agent, respectively. Fifty-four percent (123/229) of the ticks collected from New York were B. burgdorferi positive; 4% (9/229) of these ticks contained both HGE agent and B. burgdorferi. This finding indicates that animals with Lyme borreliosis may be also exposed to the etiologic agent of HGE. More extensive laboratory diagnosis may be necessary when multiple tick-borne diseases are suspected in animals.