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Abstract

Objective—To evaluate the effect of head position on intraocular pressure (IOP) in horses.

Animals—30 horses.

Procedures—Horses were sedated with detomidine HCl (0.01 mg/kg, IV). Auriculopalpebral nerve blocks were applied bilaterally with 2% lidocaine HCl. The corneas of both eyes were anesthetized with ophthalmic 0.5% proparacaine solution. Intraocular pressures were measured with an applanation tonometer with the head positioned below and above heart level. The mean of 3 readings was taken for each eye at each position for data analysis. The effect of head position on IOP was assessed and generalized estimating equations were used to adjust for the correlation from repeated measures of the same eye and intereye correlation from the same horse.

Results—Of the 60 eyes, 52 (87%) had increased IOP when measured below the heart level. A significant difference (mean ± SE, 8.20 ± 1.01 mm Hg) was seen in the mean IOP when the head was above (17.5 ± 0.8 mm Hg) or below (25.7 ± 1.2 mm Hg) heart level. No significant effect of sex, age, or neck length on IOP change was found.

Conclusions and Clinical Relevance—Head position has a significant effect on the IOP of horses. Failure to maintain a consistent head position between IOP measurements could potentially prevent the meaningful interpretation of perceived aberrations or changes in IOP.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine effects of the topically applied calcium-channel blocker flunarizine on intraocular pressure (IOP) in clinically normal dogs.

Animals—20 dogs.

Procedures—Baseline diurnal IOPs were determined by use of a rebound tonometer on 2 consecutive days. Subsequently, 1 randomly chosen eye of each dog was treated topically twice daily for 5 days with 0.5% flunarizine. During this treatment period, diurnal IOPs were measured. In addition, pupillary diameter and mean arterial blood pressure (MAP) were evaluated. Serum flunarizine concentrations were measured on treatment day 5. Intraday fluctuation of IOP was analyzed by use of an ANOVA for repeated measures and a trend test. Changes in IOP from baseline values were assessed and compared with IOPs for the days of treatment. Values were also compared between treated and untreated eyes.

Results—A significant intraday fluctuation in baseline IOP was detected, which was highest in the morning (mean ± SE, 15.8 ± 0.63 mm Hg) and lowest at night (12.9 ± 0.61 mm Hg). After 2 days of treatment, there was a significant decrease in IOP from baseline values in treated (0.93 ± 0.35 mm Hg) and untreated (0.95 ± 0.34 mm Hg) eyes. There was no significant treatment effect on pupillary diameter or MAP. Flunarizine was detected in serum samples of all dogs (mean ± SD, 3.89 ± 6.36 μg/L).

Conclusions and Clinical Relevance—Topically applied flunarizine decreased IOP in dogs after 2 days of twice-daily application. This calcium-channel blocker could be effective in the treatment of dogs with glaucoma.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

Porcine interferon-γ (poIFN-γ) and porcine granulocyte-macrophage colony-stimulating factor (poGM-CSF) are multifunctional cytokines that exhibit robust antiviral activity against porcine reproductive and respiratory syndrome virus (PRRSV). In this study, the immunoadjuvant effects of recombinant poIFN-γ-poGM-CSF fusion protein in inactivated PRRSV vaccine administered to piglets were assessed.

ANIMALS

Twenty-eight 4-week-old specific pathogen-free piglets.

METHODS

The experimental piglets were divided into control, highly pathologic PRRSV, PRRSV killed virus vaccine (KV), poIFN-γ-poGM-CSF, KV + 1.0 mg poIFN-γ-poGM-CSF, KV + 2.0 mg poIFN-γ-poGM-CSF, and KV + 4.0 mg poIFN-γ-poGM-CSF groups. A recombinant poIFN-γ-linker-poGM-CSF fusion gene was constructed via splicing by overlap extension PCR and prepared using an Escherichia coli expression system, after which its adjuvant activity in the context of PRRSV KV administration was assessed.

RESULTS

This analysis revealed the successful construction of the poIFN-γ-linker-poGM-CSF fusion gene via splicing by overlap extension PCR, with recombinant poIFN-γ-linker-poGM-CSF successfully being prepared in E coli with a plasmid vector for expressing thioredoxin fusion proteins with an enterokinase site. Importantly, the coadministration of poIFN-γ-linker-poGM-CSF and PRRSV KV significantly increased neutralizing antibody titers, accelerated viral clearance, reduced clinical symptoms, and prevented highly pathogenic PRRSV infection.

CLINICAL RELEVANCE

The recombinant poIFN-γ-poGM-CSF fusion protein is a promising candidate adjuvant for use in the context of swine immunization and viral challenge.

Open access
in American Journal of Veterinary Research

Abstract

Objective—To identify cardiac mechanisms that contribute to adaptation to high altitudes in Tibetan antelope (Pantholops hodgsonii).

Animals—9 male Tibetan antelope and 10 male Tibetan sheep (Ovis aries).

Procedures—Tibetan antelope and Tibetan sheep inhabiting a region with an altitude of 4,300 m were captured, and several cardiac variables were measured. Expression of genes for atrial natriuretic peptide, brain natriuretic peptide, and calcium-calmodulin–dependent protein kinase II δ was measured via real-time PCR assay.

Results—Ratios of heart weight to body weight for Tibetan antelope were significantly greater than those of Tibetan sheep, but ratios of right-left ventricular weights were similar. Mean ± SD baseline heart rate (26.33 ± 6.15 beats/min) and systolic arterial blood pressure (97.75 ± 9.56 mm Hg) of antelope were significantly lower than those of sheep (34.20 ± 6.57 beats/min and 130.06 ± 17.79 mm Hg, respectively). The maximum rate of rise in ventricular pressure in antelope was similar to that in Tibetan sheep, but after exposure to air providing a fraction of inspired oxygen of 14.6% or 12.5% (ie, hypoxic conditions), the maximum rate of rise in ventricular pressure of the antelope increased significantly to 145.1% or 148.1%, respectively, whereas that of the sheep decreased to 68.4% or 70.5%, respectively. Gene expression of calcium-calmodulin–dependent protein kinase II δ and atrial natriuretic peptide, but not brain natriuretic peptide, in the left ventricle of the heart was significantly higher in antelope than in sheep.

Conclusions and Clinical Relevance—Hearts of the Tibetan antelope in this study were well adapted to high-altitude hypoxia as shown by higher heart weight ratios, cardiac contractility in hypoxic conditions, and expression of key genes regulating cardiac contractility and cardiac hypertrophy, compared with values for Tibetan sheep.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

Orthohantaviruses (genus Orthohantavirus, family Hantaviridae of order Bunyavirales) are rodent-borne viruses causing 2 human diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), which are mainly prevalent in Eurasia and the Americas, respectively. We initiated this study to investigate and analyze the Orthohantaviruses infection in rodent reservoirs and humans in the Hubei Province of China from 1984 to 2010.

SAMPLE

The study included 10,314 mouse and 43,753 human serum samples.

PROCEDURES

In this study, we analyzed the incidence of Orthohantavirus infection in humans and observed changes in rodent reservoirs in Hubei Province.

RESULTS

The results indicated that although the incidence of HFRS declined from the 1990s, the human inapparent infection did not decrease dramatically. Although elements of the disease ecology have changed over the study period, Apodemus agrarius and Rattus norvegicus remain the major species and a constituent ratio of Rattus norvegicus increased. Rodent population density fluctuated between 16.65% and 2.14%, and decreased quinquennially, showing an obvious downward trend in recent years. The average orthohantaviruses-carrying rate was 6.36%, of which the lowest rate was 2.92% from 2006 to 2010. The analysis of rodent species composition showed that Rattus norvegicus and Apodemus agrarius were the dominant species over time (68.6% [1984 to 1987] and 90.4% [2000 to 2011]), while the composition and variety of other species decreased. The density of rodents was closely related to the incidence of HFRS (r = 0.910, P = .032).

CLINICAL RELEVANCE

Our long-term investigation demonstrated that the occurrence of HFRS is closely related to rodent demographic patterns. Therefore, rodent monitoring and rodent control measures for prevention against HFRS in Hubei are warranted.

Open access
in American Journal of Veterinary Research