Evaluation of laser Doppler flowmetry for measuring coronary band and laminar microcirculatory blood flow in clinically normal horses.

Once daily for 3 days, laser Doppler flowmetry was used in 5 healthy, nonsedated adult horses to evaluate coronary band and laminar microcirculatory blood flow (MBF) in both forelimbs. The coronary band had significantly (P < 0.05) higher MBF than did the laminae on the days evaluated. Significant variation in MBF was not found over the 3-day measurement period in any one site. Significant (P < 0.05) variation was found in coronary band MBF among horses. This variation was not observed in laminar MBF. On occlusion of the digital arteries at the level of the fetlock, marked decrease in coronary band and laminar MBF was observed. Twenty minutes after IV administration of acetylpromazine, marked increase in coronary band and laminar MBF was observed. The technique was easily performed in standing nonsedated horses, did not inflict discomfort, lacked complications, and measurements were repeatable. This technique provides an index of digital MBF, either intermittently or continuously, avoiding introduction of invasive variables associated with other techniques.

Combined analysis of tall fescue steer grazing studies in the Eastern United States.

The mixed-models procedure (MMP) was used to analyze pooled data sets from 12 independent studies conducted during the last 13 yr at nine locations in seven states to provide combined estimates of daily gains by beef steers (Bos taurus) grazing tall fescue (Festuca arundinacea Schreb.) pastures free of (E-) or infested (E+) at different levels with the endophytic fungus Acremonium coenophialum. Treatments included low-infestation (< or = 5% E+), moderate-infestation (> or = 20 to < or = 35% E+), and high-infestation (> or = 50 to < or = 97% E+) tall fescue pastures, and, in tall fescue-clover (Trifolium spp.) mixtures, pastures at the same E+ levels with approximately 25 and 10% clover in spring and summer stands, respectively. Spring, summer, and combined spring+summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range; detected relationships that had not been apparent in the individual studies, such as the interactions between clover presence and E+ infestation levels; and provided a more coherent body of information than did the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects.

Viscosity and rheologic properties of blood from clinically normal horses.

Blood viscosity (BV) was measured in 32 healthy horses at 6 spindle speeds (60, 30, 12, 6, 3, and 1.5 rpm) and for PCV of 40%, using a digital rotational cone and plate microviscometer. Also, in 7 of 32 horses, BV was measured 3 times each, for 3 PCV values (20, 40, and 60%), and at each spindle speed to determine effect of PCV on BV and machine and among-horse variations. Total plasma protein and fibrinogen concentrations were measured in all horses, using a standard refractometer and heat precipitation, respectively. In 7 of 32 horses, quantitative fibrinogen concentration was measured, using a quantitative fibrinogen assay. Plasma protein and fibrinogen concentrations were measured to determine their effect on BV. Plasma total protein (6.0 to 7.5 g/dl) and fibrinogen (100 to 400 mg/dl) concentrations were within normal reference range for our laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of total protein concentration and viscosity of synovial fluid from the tibiotarsal joints of horses.

Viscosity of synovial fluid (SF) from 29 clinically normal horses was determined by use of a rotational cone and plate microviscosimeter. Total protein concentration in the SF of the 29 horses, as measured with a refractometer, was less than 2.5 g/dl. When the Coomassie brilliant blue test was used to determine total protein concentration in SF for 15 horses, the mean value was 1,088 mg/dl. Viscosity values at 60, 30, 12, 6, 3, and 1.5 revolutions/min (rpm) spindle speed were 4.41 +/- 1.54 centipoise (cp), 5.29 +/- 1.94 cp, 6.76 +/- 2.76 cp, 8.52 +/- 4.27 cp. 10.41 +/- 6.30 cp, and 13.07 +/- 9.05 cp, respectively. Synovial fluid viscosity increased with decreasing rpm and shear rate, but the shape of the curve for each horse fitted the asymptotic curve. The rotational cone and plate microviscosimeter was an accurate instrument in measuring SF viscosity at multiple rpm or shear rates in horses. The values obtained on clinically normal horses in this study will serve as a baseline for comparison in the evaluation of horses with joint disease.

Treatment of dogs in hemorrhagic shock by intraosseous infusion of hypertonic saline and dextran.

Under isoflurane anesthesia, 50% of the calculated blood volume was removed from 11 dogs. After 30 minutes, five dogs were treated with hypertonic saline and dextran (HSD) (5 mL/kg) followed by isotonic saline solution (2 mL/kg) intraosseously. Six dogs (controls) received isotonic saline (7 mL/kg) intraosseously. All treatments were administered through the medullary cavity of the tibia over a 30-minute period. Cardiac output, mean arterial pressure, central venous pressure, packed cell volume, total protein, and blood gases were monitored for 4 hours. Cardiac output, mean arterial pressure, and circulating volume (indicated by packed cell volume and total protein) were significantly improved after administration of HSD. We conclude that intraosseous infusion of HSD is efficacious in treating hemorrhagic shock and believe the technique may prove to be useful in clinical situations when intravenous lines cannot be established rapidly.

Neutrophil function in dogs with congenital ciliary dyskinesia.

In vitro neutrophil function was assessed in two English Springer Spaniel dogs, two Bichon Frise dogs, and one Chow Chow dog with congenital ciliary dyskinesia; three clinically normal English Springer Spaniel dogs that were presumed heterozygous for congenital ciliary dyskinesia; and five control dogs. Chemotaxis and random migration in affected and heterozygous dogs were found to be comparable to those of control dogs. Increased (P less than or equal to 0.05) neutrophil adhesion, antibody dependent cell-mediated cytotoxicity, iodination of proteins, and oxygen radical production in neutrophils from affected dogs were probably the result of chronic bacterial infection in vivo. Bacterial ingestion by neutrophils from the three heterozygous English Springer Spaniel dogs was significantly increased compared to control dogs but was not different from affected English Springer Spaniel dogs, suggesting a breed-related phenomenon. Significant decreases in neutrophil function were not seen in any of the dogs with congenital ciliary dyskinesia, indicating that a defective microtubular system is not shared by respiratory cilia and neutrophils and that defective neutrophil function does not contribute to respiratory infection.

Cyclic hormonogenesis in gray collie dogs: interactions of hematopoietic and endocrine systems.

Cortisol, ACTH, T4, and T3 concentrations were determined in six cyclic hematopoietic (CH) dogs to determine if hormonal cycles were a feature of this hematopoietic disorder. It was determined that there were 12- to 14-day cycles of these hormones in CH dogs. Plasma cortisol and ACTH concentrations peaked 4-8 days after the onset of neutropenia and were concurrent with peak neutrophil counts. The peak ACTH concentration occurred 1-2 days before or concurrent with the cortisol peak concentration. T4 and T3 peak concentrations were opposite the cortisol cycles, and maximal concentrations were seen when cortisol levels were lowest. ACTH, GH-releasing factor and TRH response tests were performed in the CH dogs. No frank deficiencies in hormone production were seen with the ACTH, GH-releasing factor, and TRH responses in CH dogs relative to those in normal dogs. It was concluded that cyclic hormonogenesis is a central feature of CH disease. These findings are the first demonstration of extrahematopoietic system cyclicity in this rare disease and suggest the presence of common regulatory factors in the hematopoietic and endocrine systems.

Creutzfeldt-Jakob disease treated with amantadine.

A case of Creutzfeldt-Jakob disease treated with amantadine showed considerable initial improvement, followed by a period of almost five years during which the patient remained in a relatively stable condition until he died accidentally. The diagnosis was confirmed histologically.

Creutzfeldt-Jakob disease treated with amantidine. A report of two cases.

The treatment of two cases of Creutzfeldt-Jakob disease with amantidine is described. The first case made a remarkable initial improvement which was sustained for two months, but then deteriorated and died. Histological examination of the brain showed changes consistent with early Creutzfeldt-Jakob disease. The second case which was clinically one of Creutzfeldt-Jakob disease has now been followed for 30 months since the start of treatment and appears to be cured. It is considered that amantidine has a definite effect in this disease and it is suggested that its mode of action, though unknown, is more likely to be metabolic than antiviral.