Marbofloxacin for the treatment of experimentally induced Mycoplasma haemofelis infection in cats.

BACKGROUND: Administration of tetracyclines or fluoroquinolones is associated with improvement in clinical and laboratory abnormalities in cats infected with Mycoplasma haemofelis. No treatment protocol has consistently eliminated the organism, and antimicrobial susceptibility may vary among M. haemofelis isolates. Continued search for effective therapies is warranted. HYPOTHESIS: Marbofloxacin administered at the onset of clinical illness will be safe and effective for the treatment of M. haemofelis. ANIMALS: Fourteen young adult, laboratory-reared cats housed together in a specific pathogen-free facility. METHODS: Twelve cats were inoculated IV with 2.0 mL of blood from 2 M. haemofelis positive cats. Clinical parameters were assessed daily. CBC and hemoplasma polymerase chain reaction (PCR) assay were performed before inoculation, weekly for 1-3 weeks postinoculation (PI) and twice weekly 3-6 weeks PI. Treatment with marbofloxacin (2.75 mg/kg PO daily for 14 days) was initiated in 6 randomly selected cats when PCV was <30% or fever was >102.5 degrees F (39.2 degrees C). Cats that were PCR positive on day 7 of therapy were treated for 28 days. Cats that were PCR negative on day 42 PI were treated with 20 mg/kg methylprednisolone acetate IM on day 50 PI. RESULTS: Significant differences between groups on some days after inoculation included higher PCV and red blood cell counts, lower mean cell volume, and higher mean cell hemoglobin content in marbofloxacin-treated cats. No differences in PCR assay results were noted between groups. CONCLUSIONS AND CLINICAL IMPORTANCE: Marbofloxacin was safe and resulted in more rapid hematologic improvement in M. haemofelis-infected cats, but did not change clinical scores and did not consistently eliminate infection.

The prevalence of carotid artery stenosis in patients undergoing aortic reconstruction.

BACKGROUND: Coronary artery disease occurs frequently in patients undergoing aortic reconstruction, and it has been presumed that internal carotid artery occlusive disease is also common. This has led to the practice of screening for and repairing significant carotid lesions in asymptomatic patients prior to aortic reconstruction. The purpose of this study was to determine the true prevalence of internal carotid artery disease in these patients. METHODS: The records of 240 patients who underwent duplex ultrasound screening for carotid artery disease prior to aortic reconstruction were reviewed. Surgery was performed for aortic aneurysm (AA) or aorto-iliac occlusive disease (AO). The prevalence of hyperlipidemia and coronary artery disease was similar between the two groups, but tobacco use, hypertension, and diabetes mellitus differed. RESULTS: Internal carotid artery stenosis > or = 50% occurred in 26.7% of the total group (64 of 240 cases). Stenosis > or = 50% was more common in the AO group (40 of 101 cases, 39.6%) than the AA group (24 of 139 cases, 17.3%, P = 0.0001). Severe disease (70% to 99%) was also more common in the AO group than the AA group (9.9% versus 3.6%, P = 0.0464). CONCLUSION: Internal carotid artery disease occurs commonly in patients undergoing aortic reconstruction, and screening is worthwhile. Significant disease is more common in patients with aorto-iliac occlusive disease than in those with aortic aneurysm, although atherosclerotic risk factors occur with varying frequency in the two groups. These findings suggest that additional factors may contribute to the higher prevalence of internal carotid artery stenosis in aorto-iliac occlusive disease.

Effect of primary phase feline immunodeficiency virus infection on cats with chronic toxoplasmosis.

The effect of primary phase feline immunodeficiency virus (FIV) infection on clinical signs, hematological values, Toxoplasma gondii oocyst shedding, T. gondii-specific serology, T. gondii-specific cell-mediated immune responses, non-specific cell-mediated immune responses, and lymphocyte subpopulations from cats with experimentally induced chronic toxoplasmosis was studied. No significant clinical or hematologic abnormalities were noted following inoculation with FIV. T. gondii-specific IgM was significantly increased, concanavalin A, T. gondii tachyzoite antigen and T. gondii secretory antigen induction of lymphocyte transformation were significantly suppressed, and CD4+ cell numbers were significantly decreased following inoculation with FIV. The changes were attributed to FIV effects on the immune system and resultant activated toxoplasmosis.

Detection of Toxoplasma gondii in the milk of experimentally infected lactating cats.

Tachyzoites of Toxoplasma gondii have been found in the milk of sheep, goats, cows and mice and infection by ingestion of raw goat milk has been documented in humans. Lactational transmission from infected cats to their kittens is suspected but the organism has not been detected in the milk. The purpose of this study was to demonstrate the presence of T. gondii in the milk of experimentally infected cats. Pregnant specific pathogen free cats were inoculated orally with T. gondii at various times prior to parturition. Feces were examined for oocyst shedding after sugar solution centrifugation. Milk was collected for polymerase chain reaction (PCR) and bioassay in mice. T. gondii was detected in the milk of five of six cats by either bioassay or PCR.

Comparison of latex agglutination, indirect hemagglutination, and ELISA techniques for the detection of Toxoplasma gondii-specific antibodies in the serum of cats.

The primary purpose of this study was to determine whether commercially available latex agglutination and indirect hemagglutination kits for the detection of Toxoplasma gondii-specific antibodies were capable of detecting T. gondii-specific immunoglobulin M (IgM) in the serum of cats. Serum samples from 35 cats containing either T. gondii-specific IgM, T. gondii-specific immunoglobulin G (IgG), or both were collected. Each serum sample was assayed using a latex agglutination kit, an indirect hemagglutination kit, an enzyme-linked immunosorbent assay (ELISA) for the detection of T. gondii-specific IgG, and an ELISA for the detection of T. gondii-specific IgM. When serum samples containing only T. gondii-specific IgM as determined by ELISA were assayed, the latex agglutination kit and the indirect hemagglutination kit detected antibodies in 33.3% and 13.3%, respectively. When T. gondii-specific IgG was present in a serum sample, the results from the latex agglutination kit, the indirect hemagglutination kit, and the IgG-ELISA were similar; however, there was a wide variation in titer magnitude results between the three assays. It was concluded that the latex agglutination kit and the indirect hemagglutination kit did not adequately detect T. gondii-specific IgM in feline serum.

Effect of feline immunodeficiency virus infection on Toxoplasma gondii-specific humoral and cell-mediated immune responses of cats with serologic evidence of toxoplasmosis.

Serum samples from 89 cats with serologic evidence of toxoplasmosis were identified by using an enzyme-linked immunosorbent assay (ELISA) that detected Toxoplasma gondii-specific immunoglobulin M (IgM) or T. gondii-specific immunoglobulin G (IgG). Concurrent feline immunodeficiency virus (FIV) infection was detected in 36 cats using an ELISA for detection of FIV-specific IgG. The majority of the cats in both the FIV-seropositive and FIV-seronegative groups were male and > 5 years of age. FIV-seropositive cats were more likely to have T. gondii IgM titers without IgG (P < 0.05) or any T. gondii IgM titer (P < 0.05) than were FIV-seronegative cats. FIV-seronegative cats (1328) had a higher T. gondii IgG geometric mean titer than did FIV-seropositive cats (724) and were more likely to have T. gondii IgG titers > 1:2048 than were FIV-seropositive cats (P < 0.05). Cats with serologic evidence of both T. gondii and FIV infections had persistent T. gondii IgM titers for > 12 weeks. Lymphoblast transformation in response to concanavalin A, T. gondii-specific intracellular antigens, and T. gondii-specific secretory antigens was compared in T. gondii seropositive and FIV-seronegative cats, cats with serologic evidence of T. gondii infection alone, and cats with serologic evidence of concurrent FIV and T. gondii infections. Lymphocytes from all but one cat in the FIV-seropositive group responded to concanavalin A. Whereas lymphocytes from FIV-seronegative cats with serologic evidence of toxoplasmosis responded to T. gondii-specific antigens, four of five of the FIV-seropositive cats with concurrent serologic evidence of toxoplasmosis did not.

Inoculation with Bartonella henselae followed by feline herpesvirus 1 fails to activate ocular toxoplasmosis in chronically infected cats.

Infection by Toxoplasma gondii is very common in cats although most remain disease free. The factors that trigger development of uveitis in some cats infected with T gondii have not been elucidated, but infection by more than one organism may be contributory. In this study, cats chronically infected with T gondii were inoculated with Bartonella henselae followed by FHV-1 to test the hypothesis that immune stimulation by multiple infections will reactivate ocular toxoplasmosis. Anterior uveitis and chorioretinitis were not detected in the cats with chronic T gondii infection thus allowing rejection of the hypothesis using this experimental design.

Intraocular pressure in normal llamas (Lama glama) and alpacas (Lama pacos).

OBJECTIVE: To determine the mean intraocular pressure in llamas (Lama glama) and alpacas (Lama pacos) using applanation tonometry.Animals studied: Ten llamas and 10 alpacas.Procedures: Intraocular pressure (IOP) was measured with a Tono-Pentrade mark XL (Mentor Ophthalmics, Inc., Norwell, MA, USA). Three values, with 5% variance, were recorded for each eye. Least-squares means were determined for IOP for each eye of llamas and alpacas. Controlling for age, differences between left and right eye were analyzed using ANOVA. Two age groups were established, less than 5 years and greater than 5 years. The effect of age on IOP within each group was analyzed by linear regression. Probability values of less than 0.05 were considered significant. RESULTS: Comparison of mean IOP between right (n = 20) and left eyes (n = 20), independent of species type, showed no differences in IOPs for llamas and alpacas. Mean IOP declined with increasing age in llamas and alpacas. Mean IOPs for 20 eyes in 10 llamas was 16.96 +/- 3.51 mmHg. Mean IOP for 20 eyes in 10 alpacas was 16.14 +/- 3.74 mmHg. Mean IOP for all eyes (n = 40), independent of species, was 16.55 +/- 3.55 mmHg. The range of IOP in normal llamas and alpacas within 2 SD (95% of the population) was 14.89+/-18.21 mmHg. CONCLUSIONS: There was no significant difference in IOP between alpacas and llamas. Mean IOP in both species decreased with increased age.

Distribution of cholinergic and adrenergic nerve fibers in the lacrimal glands of dogs.

The distribution of postganglionic autonomic nerve fibers in the lacrimal gland and gland of the third eyelid of dogs was studied by use of histochemical techniques. Adrenergic nerve distribution was identified by use of the sucrose-potassium phosphate-glyoxylic acid technique. A loose network of adrenergic nerves was found throughout the interstitium around acini and blood vessels and in vessel walls. Acetylcholinesterase staining was used to identify cholinergic nerve fibers. A cholinergic distribution pattern was found, although the cholinergic innervation appeared more dense than the adrenergic. In the gland of the third eyelid, mucus-secreting lobules and lipid-secreting lobules appeared to be equally innervated by parasympathetic fibers. These lobules could not be differentiated when the sucrose-potassium phosphate-glyoxylic acid technique was used. The techniques used in this study could not demonstrate whether direct contact was made by either cholinergic or adrenergic nerve fibers with secretory or myoepithelial cells. The presence of both nerve fiber types around acini suggests an interrelationship between the sympathetic and parasympathetic nervous system in lacrimal gland secretion in dogs.

Detection of Toxoplasma gondii antigen-containing immune complexes in the serum of cats.

Enzyme-linked immunosorbent assays for the detection of Toxoplasma gondii antigen-containing IgM immune complexes (T gondii-specific IgM-IC) and IgG immune complexes (T gondii-specific IgG-IC) in the serum of cats were developed. Serum from clinically ill, naturally infected cats; healthy, naturally infected cats; and healthy cats experimentally inoculated with T gondii was assayed. All combinations of T gondii-specific IgM, IgG, antigens, IgM-IC, and IgG-IC were detected in naturally infected and experimentally infected cats. Clinically ill cats and cats with ocular signs of toxoplasmosis were more likely than healthy cats to have T gondii-specific IC in serum. It was concluded that T gondii-specific IC form in the serum of cats, may play a role in clinical disease development, and affect the results of T gondii-specific IgM, IgG, and antigen serologic assays.

Analysis of aqueous humor obtained from normal eyes of llamas and alpacas.

OBJECTIVE: To evaluate composition of aqueous humor obtained from normal eyes of llamas (Lama glama) and alpacas (Lama pacos). SAMPLE POPULATION: Aqueous humor obtained from 10 male llamas and 10 male alpacas. PROCEDURE: All animals had normal eyes, as determined by ocular examination. Aqueous humor samples were obtained via paracentesis of the anterior chamber of animals that were heavily sedated. Chemical analysis included measurement of concentrations of sodium, potassium, magnesium, chloride, bicarbonate, phosphorus, and glucose as well as osmolality and pH. RESULTS: With the exception of potassium concentrations, values for aqueous humor composition did not differ significantly between llamas and alpacas. Mean +/- SD values for llamas and alpacas, respectively, were: sodium, 154.7 +/- 2.1 and 152.7 +/- 2.1 mEq/L; potassium, 5.3 +/- 0.4 and 4.6 +/- 0.4 mEq/L; magnesium, 1.8 +/- 0.1 and 1.7 +/- 0.1 mg/dl; chloride, 130.0 +/- 1.6 and 127.0 +/- 3.3 mEq/L; bicarbonate, 19.2 +/- 1.5 and 20.2 +/- 2.3 mEq/L; phosphorous, 2.7 +/- 0.3 and 2.5 +/- 0.4 mg/dl; glucose, 80.3 +/- 3.9 and 80.8 +/- 7.3 mg/dl; total protein, 29.0 +/- 8.6 and 31.5 +/- 10.1 mg/dl; and osmolality, 305.8 +/- 11.8 and 306.2 +/- 4.9 mOsm. The pH ranged from 7.5 to 8.0 for both species. Potassium concentrations were significantly higher in llamas than alpacas. CONCLUSIONS AND CLINICAL RELEVANCE: Except for potassium, composition of aqueous humor did not differ significantly between llamas and alpacas. Aqueous humor composition of llamas and alpacas is similar to that of other species that have been examined.

Toxoplasma gondii-specific antibodies in the aqueous humor of cats with toxoplasmosis.

We decided to determine whether Toxoplasma gondii-specific IgM or IgG is produced locally or is deposited in the aqueous humor of T gondii-naive cats after primary or secondary inoculation with T gondii. Cats were orally inoculated with T gondii tissue cysts during weeks 0 and 36. Aqueous humor and serum T gondii-specific IgM and IgG were measured, using ELISA, during weeks 0, 2, 4, 6, 8, 12, 16, 20, 26, 34, 38, 40, 42, 44, 48, 56, 62, 66, and 72 after primary oral inoculation. Total immunoglobulin-based Goldmann-Witmer coefficients were calculated to verify intraocular antibody production. Toxoplasma gondii-specific IgM was not detected in the aqueous humor of any cat. Data indicate that cats have transient local production of T gondii-specific IgG in the aqueous humor after primary and secondary oral inoculations with T gondii tissue cysts. The intraocular immune response to systemic T gondii infection may signal ocular recruitment of antigen-specific lymphocytes that function independently from the general humoral response to T gondii infection. Cautious interpretation of results that suggest intraocular production of T gondii-specific IgG in cats with uveitis is warranted.

Enzyme-linked immunosorbent assays for the detection of Toxoplasma gondii-specific antibodies and antigens in the aqueous humor of cats.

Serum and aqueous humor samples, collected from 14 clinically normal cats and 96 cats with clinical evidence of intraocular inflammation, were assayed with ELISA for Toxoplasma gondii-specific immunoglobulin M (IgM), T gondii-specific IgG, T gondii-specific antigens, total IgG, and total IgM. Additionally, serum was assayed with ELISA for feline leukemia virus p27 antigen and antibodies against the feline immunodeficiency virus as well as with an immunofluorescent antibody assay for antibodies against feline coronaviruses. Calculation of the Goldmann-Witmer coefficient (C-value) for the T gondii-specific antibodies detected in aqueous humor established the likelihood of local antibody production. Serologic evidence of present or prior infection by an infectious agent was found in 81.9% of the clinically affected cats from which serologic results were available (77/94 cats). Seropositive results for toxoplasmosis were found in 74.0% of the clinically affected cats. Anterior segment inflammation was found in 93.1% (81/87 cats from which information was available) of the clinically affected cats, most of which were older males. Toxoplasma gondii-specific antibodies were not detected in the aqueous humor of 6 seropositive, clinically normal cats. The C-values for aqueous T gondii antibodies were greater than 1 in 44.8% of the cats and greater than 8 in 24.0% of the cats. Response to treatment with clindamycin HCl was positive in 15/20 (75%) of the T gondii-seropositive, clinically affected cats treated with this drug. In 13/15 (86.7%) T gondii-seropositive, clinically affected cats having a C-value greater than 1, response to treatment with clindamycin HCl was positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Serologic prevalence of selected infectious diseases in cats with uveitis.

Serologic evidence of infection by Toxoplasma gondii, feline leukemia virus, feline coronaviruses, or feline immunodeficiency virus (FIV) is commonly found in cats with uveitis. Serum samples from 124 cats with uveitis were assayed by use of ELISA for the detection of T gondii-specific immunoglobulin M (IgM), IgG, and circulating antigens (Ag), as well as an ELISA for feline leukemia virus Ag, an ELISA for antibodies to FIV, and an indirect fluorescent antibody assay for antibodies to feline coronaviruses. Serologic evidence of infection by 1 or more of the infectious agents was detected in 83.1% of the samples. Serologic evidence of T gondii infection, defined as the detection of T gondii-specific IgM, IgG, or Ag in serum, was found in 74.2% of the samples. The seroprevalence of T gondii infection was significantly greater in cats with uveitis than in healthy cats from a similar geographic area. Serum samples from cats with serologic evidence of both T gondii and FIV infections were more likely to contain T gondii-specific IgM without IgG than samples from cats with serologic evidence of T gondii infection alone. Cats with serologic evidence of FIV and T gondii coinfection had a higher T gondii-specific IgM titer geometric mean and a lower T gondii-specific IgG titer geometric mean than did cats with serologic evidence of T gondii infection alone. Serologic evaluation for T gondii infection should include assays that detect IgM, IgG, and Ag, particularly in cats coinfected with FIV.

Clinical ocular toxoplasmosis in neonatal kittens.

OBJECTIVE: To describe ocular findings in kittens with congenital or early neonatal infection by Toxoplasma gondii and to determine if there are detectable differences in disease caused by three strains. ANIMALS STUDIED: Six adult female cats and the offspring from seven litters. METHODS: Four kittens from uninfected specific pathogen-free (SPF) queens and 21 kittens from SPF queens inoculated at various times late in gestation with Mozart, Maggie, or ME-49 strain of T. gondii were used. Ocular examinations were performed on queens prior to and after delivery, and on kittens weekly to bi-weekly for up to 27 weeks. Whole blood for serology was collected from all kittens at 5(1/2) to 8 weeks of age and again at 12 weeks of age or later. RESULTS: No kittens from noninfected queens developed ocular lesions or antibody to T. gondii. Three of the 24 kittens from infected queens died or were euthanized early in the study. Chorioretinitis was detected in 15 of 21 living kittens from infected queens. Two developed concurrent anterior uveitis that resolved within 1 week. Posterior segment lesions varied ophthalmoscopically between strains. Of 21 kittens from T. gondii-infected queens, six developed positive antibody titers to T. gondii during the study. All seropositive kittens were born to queens infected with Mozart strain of T. gondii. CONCLUSION: Results of this study suggest that ocular toxoplasmosis can occur without other evidence of clinical illness in kittens infected in utero or in the neonatal period, and that T. gondii strains may have varying degrees of ocular pathogenicity in cats.

Synapse formation and modification between distal retinal neurons in larval and juvenile Xenopus.

A serial section analysis of photoreceptor synaptic bases was undertaken in the clawed frog Xenopus laevis. The developmental period from tadpole stage 48 through metamorphosis was studied. Horizontal cells contacted rod and cone photoreceptors at ribbon synapses; the number of such contacts per receptor base was constant for rods, but increased for cones as a function of developmental stage. In pre-metamorphic animals bipolar cells contacted receptors only through basal junctions; their number in cone bases increased dramatically during development but was unchanged in rod bases. A densitometric estimation of the cleft width of basal junctions showed that it ranged from 10 to 18 nm, but the junctions could not be divided reliably into the 'wide' and 'narrow' categories reported for other vertebrate species. Near metamorphic climax a new type of ribbon-related bipolar cell junction appeared. Gap junctions between horizontal cells and conventional synapses of horizontal cell onto bipolar cell processes were first seen in mid-larval developmental stages.

Diaspirin crosslinked hemoglobin (DCLHb): more effective than lactated Ringer's solution in restoring central venous oxygen saturation after hemorrhagic shock in rats.

Central venous oxygen saturation (ScvO2) has been shown to reflect tissue oxygen consumption in hemorrhagic shock. The purpose of this study was to test whether the "blood substitute" diaspirin crosslinked hemoglobin (DCLHb, Baxter Healthcare, Round Lake, IL) might be more effective than lactated Ringer's solution (LR) at restoring tissue oxygenation, as measured by ScvO2, when used as a resuscitative fluid following hemorrhage. Conscious male Sprague-Dawley rats (250-350 gm) were bled through a jugular venous catheter to a target central venous base deficit of 15 +/- 2 mmol/L. Animals were immediately resuscitated with either 10% DCLHb (1:1) or LR (3:1), based on shed blood volume, followed by a maintenance infusion of LR until completion of the experiment. Central venous blood was sampled at baseline, prior to resuscitation and every 15 minutes for the first hour following resuscitation. While the baseline and pre-resuscitation ScvO2 values were not significantly different between groups, ScvO2 values were greater (P < or = 0.01) in the DCLHb group at all times following resuscitation. Furthermore, DCLHb restored SvO2 to baseline by 15 minutes after resuscitation, whereas LR resuscitation never restored ScvO2 to baseline. Since venous desaturation is one of the major compensatory mechanisms by which oxygen consumption is maintained under conditions of limited oxygen supply, these data suggest that animals resuscitated with DCLHb had a more rapid restoration of tissue oxygenation than those resuscitated with LR in this model of hemorrhagic shock.