Experimental transmission of intestinal coccidiosis to piglets: clinical, parasitological and pathological findings.

Twenty-eight piglets coming from a "specific pathogen free" herd were inoculated at three days of age with 50 000 or 100 000 sporulated oocysts of Isospora suis. Fecal samples were examined for oocyst shedding daily and several clinical parameters were recorded. Ten piglets were used as normal controls. Groups of piglets were euthanized from three days to 12 days postinoculation and routine necropsies were performed. Bacteriological, virological, parasitological and histopathological examinations were made on the intestinal tracts. The incubation period was four to five days. Clinical signs and microscopic intestinal lesions observed in the experimentally infected animals were similar to those reported in spontaneous cases of porcine neonatal coccidiosis. Lesions of villous atrophy in the small intestine seemed to result from the destruction of villous epithelial cells mainly during the peak of asexual reproduction which occurred around four to five days postinoculation. Intracellular coccidial organisms were difficult to find during the late atrophic and villous regrowth stages of the intestinal lesions. The prepatent period varied from four to seven days and the most common was five days. Eighty percent of the piglets kept alive more than four days postinoculation have shed oocysts. Piglets dosed with old sporulated oocysts (ten months old) shed many more oocysts than those infected with a fresh inoculum (less than two months old). The patent period was not determined precisely with the design of the experiment but some of the infected piglets shed oocysts for at least five days.     

Failure of dogs to shed oocysts after being fed bovine fetuses naturally infected by Neospora caninum

Neospora caninum is a protozoan that causes abortion in cattle. The dog has recently been identified as a definitive host for N. caninum. To verify if bovine fetuses can infect dogs, nine 2-4-month-old dogs were fed bovine fetuses naturally infected by N. caninum. None of the dogs excreted oocysts, seroconverted, had clinical signs or lesions compatible with N. caninum infection. Additional studies will be necessary to determine the natural mode of infection of dogs by N. caninum.     

Invasive multiple lymphangiomas in a young dog

An unusual case of multiple lymphangiomas with lymph node involvement is described. A seven-month-old, spayed female golden retriever was presented with a myriad of cystic masses in the inguinal and caudal mammary regions. She was diagnosed with congenital lymphangiomas (i.e., lymphatic hamartomas). As in human lymphangiomas, lymphatic endothelial cells expressing factor VIII-related antigen and smooth muscle were present in this case. A literature search did not identify similar characteristics in other reported canine lymphangiomas. The dog was treated surgically and had a recurrence. Following a second surgical intervention, she is now disease-free.     

Hog Cholera: IV. Detection of the Virus in Tissue Culture Preparations by the Fluorescent Antibody Technique

The fluorescent-antibody technique was employed for detection of hog cholera virus in tissue cultures inoculated with spleens of infected animals. As controls, cultures were also inoculated with material from normal swine and from those infected with other agents. In the first series 71 of 73 infected spleens, or 97 per cent, were detected. There were no false positive reactions among the controls. Results obtained with the second series of pigs showed that spleens collected during advanced stages of the disease were more satisfactory specimens than those collected earlier during the high temperature phase of infection. Findings with the third series of older swine indicated that their spleens were less satisfactory as a source of virus than those from young pigs. Tissues from freshly killed animals provided better specimen material than those from animals which had died.     

Early dexamethasone treatment after implantation of a sciatic-nerve cuff decreases the concentration of substance P in the lumbar spinal cord of rats with neuropathic pain

The main purpose of this study was to evaluate the effects of early dexamethasone treatment on pain-related peptides at an early stage in the development of neuropathic pain induced by implantation of a sciatic nerve cuff in Sprague Dawley rats (body weight 250 to 350 g). The rats were tested for touch sensitivity with the use of von Frey filaments before and 3 d after cuff implantation (n = 12) or sham surgery (n = 6). Half of the cuff-implanted rats received dexamethasone, 1 mg/kg intraperitoneally, 1 h after surgery. Spinal cords were collected on the 3rd day after surgery, and the lumbar enlargement was processed for the detection of selected peptides (neurotensin, substance P, cholecystokinin [CCK], vasoactive intestinal peptide, and calcitonin gene-related peptide) by means of liquid chromatography and tandem mass spectrometry. The right sciatic nerve of each rat was collected, fixed, and stained for histopathological evaluation. Except for neurotensin, all the peptides showed an increased concentration with neuropathic pain; however, the differences were significant (P < 0.05) only for substance P and CCK. In the animals treated with dexamethasone, mechanical allodynia was less pronounced (P < 0.01), and only the concentration of substance P was decreased significantly (P < 0.05). Sciatic nerve sections showed a decrease in C (P < 0.01) and Adelta (P < 0.03) fibres with neuropathic pain and a nearly normal percentage of C fibres after dexamethasone treatment. The dexamethasone-treated animals also had less inflammation detectable microscopically at the nerve constriction site compared with cuff-implanted animals that were not treated with dexamethasone. Our results suggest that in the early stages of neuropathic pain induced by an inflammatory process, dexamethasone may be a useful treatment and that substance P plays an important role in pain perception.     

Spiral calcium wave propagation and annihilation in Xenopus laevis oocytes

Intracellular calcium (Ca2+) is a ubiquitous second messenger. Information is encoded in the magnitude, frequency, and spatial organization of changes in the concentration of cytosolic free Ca2+. Regenerative spiral waves of release of free Ca2+ were observed by confocal microscopy in Xenopus laevis oocytes expressing muscarinic acetylcholine receptor subtypes. This pattern of Ca2+ activity is characteristic of an intracellular milieu that behaves as a regenerative excitable medium. The minimal critical radius for propagation of focal Ca2+ waves (10.4 micrometers) and the effective diffusion constant for the excitation signal (2.3 x 10(-6) square centimeters per second) were estimated from measurements of velocity and curvature of circular wavefronts expanding from foci. By modeling Ca2+ release with cellular automata, the absolute refractory period for Ca2+ stores (4.7 seconds) was determined. Other phenomena expected of an excitable medium, such as wave propagation of undiminished amplitude and annihilation of colliding wavefronts, were observed.     

Inhibition of factor VIIa-tissue factor coagulation activity by a hybrid protein

Lipoprotein-associated coagulation inhibitor (LACI) appears to inhibit tissue factor (TF)-induced blood coagulation by forming a quaternary inhibitory complex containing factor Xa, LACI, factor VIIa, and TF. A genetically engineered hybrid protein consisting of the light chain of factor Xa and the first Kunitz-type inhibitor domain of LACI is shown to directly inhibit the activity of the factor VIIa-TF catalytic complex. Unlike inhibition of factor VIIa-TF activity by native LACI, inhibition by the hybrid protein is not dependent on factor Xa. In an assay of TF-induced coagulation, 50% TF inhibition occurs with hybrid protein at 35 nanograms per milliliter, whereas LACI at 2.5 micrograms per milliliter is required for an equivalent effect. gamma-Carboxylation of glutamic acid residues in the factor Xa light chain portion of the hybrid protein is required for inhibitory activity, indicating that the first Kunitz-type domain of LACI alone is not sufficient for inhibition of factor VIIa-TF.     

Serum zinc, iron and copper status during early gestation in sows fed a folic acid-supplemented diet

The purpose of this trial was to determine whether an addition of folic acid to a commercial diet would affect serum Zn, Fe and Cu status in sows between weaning and 30 d of gestation. At weaning, 162 sows were assigned randomly to six groups and housed in individual cages fitted on a slatted floor. There were six treatments according to a 2 X 3 factorial arrangement: two levels of supplementary folic acid (0 and 5 mg/kg of diet) and three treatments to stimulate ovulation (none, flushing and pregnant mare serum gonadotropin [PMSG] i.m. injection). Control groups were fed a commercial-type diet, and folic acid-treated groups were fed the same diet supplemented with 5 mg/kg of pteroylglutamic acid. All sows were mated twice within 7 d after weaning. Of the 162 animals originally selected, 123 sows were pregnant and used in this trial. Serum folates, Zn, Cu and Fe were measured at weaning, mating and 30 d of gestation. Serum Cu, Zn and folates increased between weaning and mating, and then decreased to 30 d of gestation. Supplementing the commercial diet with folic acid elevated serum folates between weaning and d 30 of gestation (P less than .001). Folic acid supplementation also was associated with a higher level of serum Zn at 30 d of gestation. Supplemental folic acid had no effect on the pattern of serum Cu and Fe throughout the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)