Iron status, as determined by hematologic values, serum iron concentration, total iron-binding capacity, and zinc protoporphyrin concentration, was determined in 2 groups of 6 nonpregnant monkeys. Monkeys of groups 1 and 2 had 10 and 5%, respectively, of their blood volume withdrawn per week for up to 10 weeks or until blood hemoglobin concentration was less than or equal to 10 g/dl. A third group of 6 monkeys served as controls. The majority (8/12) of the monkeys became anemic (hemoglobin concentration, less than or equal to 10 g/dl) after approximately 30 to 70% (mean, 49%) of their blood volume was removed. Anemia was accompanied by decrease in serum iron concentration and percentage of transferrin saturation. Microcytosis, hypochromasia, and increased zinc protoporphyrin concentration, all hematologic characteristics of iron deficiency, developed later. The calculated iron stores ranged from 1 to 133 mg, with mean value of 51 mg. Iron-depleted monkeys had mean calculated available iron store of 20.8 mg, whereas iron-replete monkeys had mean available iron store of 114.0 mg. Changes were not observed in monkeys of the control group during the study period. None of the baseline hematologic or biochemical analytes measured were good predictors of iron stores. The diet used at the research center did not provide sufficient iron to prevent iron deficiency in most of the monkeys from which a total amount of 30 to 70% of blood volume at 5 or 10%/week was withdrawn. Studies requiring that much blood may need to be modified to include iron supplementation, reduction of sample volume, or iron replacement after termination of projects.

One hundred and fifty lactating Holstein cows from 2 genetic lines selected for high and average milk production were used in the study. Sera from 6 annual herd tests were analyzed by agar-gel immunodiffusion test for antibodies to bovine leukemia virus. Odds of being seropositive were analyzed by use of stepwise and backward logistic regression procedures. Analysis within birth year revealed that estimated ln odds increased by 0.19/year of age among cows of the high genetic line and by 0.43 among cows of the average genetic line. This was accompanied by a more important cohort effect among high producers than among average producers.

A protocol for performing slit-lamp fluorophotometry of the anterior chamber in dogs was established. The technique was then used to develop a model of blood-aqueous barrier disruption that can be used for comparative testing of ophthalmic anti-inflammatory drugs. It was determined that barrier disruption induced by a slow, controlled paracentesis of a small volume of aqueous humor may provide the most reliable model for drug testing. Additionally, fluorophotometry proved to be a sensitive and accurate means of detecting breakdown of the blood-aqueous barrier.

The effect of various confinement conditions on physical fitness in dogs was evaluated. Eighteen 9.5- to 10-month-old female purpose-bred Beagles were maintained individually for 3 months at a time in 1 of 6 confinement conditions: Condition A--an outdoor housing area with a conventional dog house and free access to a 6.1 X 9.1-m pen; condition B--outdoor kennel with a conventional dog house and free access to a 1.8 X 6.1-m run; condition C--indoor environmentally controlled 1.2 X 3.66-m run; condition D--0.9 X 1.2 X 0.84-m conventional laboratory cage in an indoor environmentally controlled room; condition E--0.9 X 1.2 X 0.84-m conventional laboratory cage in an indoor environmentally controlled room with treadmill exercise (7 km/h at a 10% grade) for 30 min/d, 5 d/wk; condition F--0.71 X 0.86 X 0.69-m conventional laboratory cage in an indoor environmentally controlled room. During the final week of each 3-month interval, muscle succinate dehydrogenase enzyme activities and submaximal exercise heart rates (during treadmill exercise) were determined to estimate physical fitness. Also, 5 days after being moved into a different housing condition, blood samples were collected for plasma cortisol determination. The type of confinement condition for dogs had little effect on muscle succinate dehydrogenase activity, but had a modest effect on submaximal exercise heart rates of dogs. At the fifth and tenth minutes of the treadmill exercise period, heart rates of dogs maintained in the smallest cages (condition F) were higher than those of dogs maintained in outside pens and runs (conditions A and B), indicating decreased fitness in the dogs maintained in the smallest cages. Differences in heart rates were not detected among dogs in other conditions. The confinement conditions used in this study had no detectable effect on plasma cortisol concentrations. We concluded that neither cage or pen size nor a regular mandatory exercise program substantially impacted on physical fitness of laboratory confined dogs, as long as the cages complied with federal standards and guidelines. Dogs maintained in substandard cages did have modest decreases in fitness.

Cellular oncogenes of genomic DNA in 6 canine primary mammary tumors were screened by Southern blot analysis, using 7 oncogene probes. A canine genomic oncogene related to the human c-yes-1 oncogene was detected as abnormal bands in solid carcinoma genomic DNA digested with Ecori, HindIII, HindIII-EcoRI, or HindIII-BamHI. Comparison was made between other tumor specimens and control specimens obtained from 4 clinically normal dogs-1 mixed breed and 3 Shiba Inu dogs (the same breed as the dog from which the solid carcinoma was obtained). These abnormal bands were 0. 1 to 1 kilobase shorter than the normal gene. However, digestion of genomic DNA obtained from normal WBC of this dog also produced all of the abnormal bands as observed in digested DNA from the solid carcinoma tissue. Therefore, in this dog, the genomic DNA of all somatic cells from the ontogenic stage still had the abnormal sequences related to the human c-yes-1 oncogene, and it is possible that this abnormal structure may have some role (eg, as an initiator) in tumorigenesis or the progression of this tumor.

Recent studies indicate that in animals with marked cardiac hypertrophy, there is depressed function of Ca2+ sequestration by myocardial sarcoplasmic reticulum (SR) because of down regulation of the Ca2+-ATPase gene. However, in several animal models we have observed enhancement of myocardial Ca2+ sequestration in response to chronic cardiac stimulation. We tested the hypothesis that in animals with mild cardiac hypertrophy, there is enhanced Ca2+ -cycling activity by the SR Ca2+ pump and Ca2+ -release channel. Because creatine kinase activity is consistently decreased in cardiomyopathy, we also determined whether enhanced Ca2+ cycling was accompanied by down regulation or inhibition of the creatine kinase system. Mild cardiac hypertrophy was induced by volume overload; 2% salt was added to the diet of 2-week-old turkey poults for 4 weeks. Compared with age-matched controls, volume overload resulted in 14.3% increase in heart weight and 21.5% increase in heart-to-body weight ratios. The hypertrophied heart had approximately 20% increased activities of the SR Ca2+ pump and the SR Ca2+ channel. Net Ca2+ transport was increased by 16.5%. Compared with controls and in contrast to several other myocardial enzymes, creatine kinase activity was diminished in the hypertrophied hearts by 23% and creatine content was decreased by 8%. Differences between groups were not detected for lactate dehydrogenase, aspartate transaminase, and alanine transaminase. We concluded that an early adaptation of the myocardium undergoing hypertrophy in compensatory response to functional overload is an enhancement of Ca2+ Cycling activity by the Ca2+ pump and Ca2+ channel of the SR. In contrast to late-stage hypertrophy, there is no evidence for down regulation of the Ca2+-ATPase gene. However, creatine kinase activity and creatine content are diminished by mild cardiac hypertrophy.

Comparisons of the MacKay-Marg and Tono-Pen applanation tonometers in open and closed in vitro systems were made for the eyes of cats. Both instruments significantly underestimated intraocular pressure (IOP) vs direct manometry (P < 0.001), but in readily predictable manner, with high coefficients of determination (r2 = 0.99). For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.36 X (MacKay-Marg measurement) - 1.67 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.37 X (Tono-Pen measurement) + 0.8 mm of Hg, using measurements from 11 enucleated eyes. In vivo comparisons were initially made in 81 clinically normal eyes (n = 41 cats) by applying the Tono-Pen first followed by the MacKay-Marg. Compared with the MacKay-Marg, the Tono-Pen significantly (P < 0.001) underestimated IOP in these cats. When the order of tonometer applanation was subsequently reversed in 73 clinically normal eyes (n = 37 cats) the Tono-pen again significantly (P < 0.001) underestimated IOP, compared with the MacKay-Marg. Alterations in tonometer order did not result in significant differences in measured IOP for the MacKay-Marg when compared with itself, but Tono-Pen measurements were significantly (P < 0.05) less when its use followed rather than preceded, that of the MacKay-Marg. Mean (+/- SD) IOP in clinically normal cats when each tonometer was used first was 22.6 +/- 4.0 mm of Hg (range, 14 to 32 mm of Hg) for the MacKay-Marg and 19.7 +/- 5.6 mm of Hg (9 to 31 mm of Hg) for the Tono-Pen. The mean (+/- SD) absolute value of the differences between MacKay-Marg measurements and those obtained by use of the Tono-Pen was 3.2 +/- 3.1 (range, 0 to 13 mm of Hg difference).

Thirty-seven local isolates of Actinobacillus suis-like organisms from diseased and clinically normal horses and 1 Ilama were compared with reference strains of A suis, A lignieresii, A equuli, A capsulatus, A hominis, A (Pasteurella) ureae, and equine A suis-like organisms (ASLO) previously described in literature. Comparison was by cultural characteristics, carbohydrate fermentation, enzyme profiles, and whole-cell protein polyacrylamide gel electrophoresis. Carbohydrate fermentation, determined by API-CH gallery, divided 36 equine ASLO isolates into 6 API-CH biotypes. The Ilama isolate was an additional distinct biotype. The biochemical comparisons between A suis and ASLO did not reveal remarkable and consistent differences. Enzyme analysis revealed 5 API-ZYM biotypes, one of which included the same strains as one of the API-CH biotypes and consisted in both instances of 4 esculin-negative ASLO cultures and the reference strain of A lignieresii. We conclude that the 4 strains were hemolytic variants of A lignieresii. Protein electrophoresis disclosed 15 banding patterns, 10 of which represented equine ASLO strains. The reference strains of A suis shared the pattern predominant among equine ASLO. Four of the remaining reference strains of Actinobacillus species each had a unique profile, whereas the type strain of A capsulatus and the Ilama isolate had similar profiles. The groupings of cultures resulting from the different testing methods had little relation to each other and to the anatomic source of the strains except the strains comprising API-CH biotype III, which originated in the equine respiratory tract, and the A lignieressi cluster.

Renal mass was surgically reduced in 78 dogs by uninephrectomy or by combined renal infarction and uninephrectomy. Renal clearance of inulin and renal clearance of exogenous creatinine were determined simultaneously, and the creatinine to inulin clearance (C/I) ratio was calculated. Clearance procedures were performed 2 to 3 months after reduction of renal mass, and were repeated at intervals thereafter. Overall, the C/I ratio was 1.008 +/- 0.007 for 192 determinations, with a highly significant correlation (R2 = 0.994, P < 0.0001) between creatinine clearance and inulin clearance. There was no significant effect of gender of dogs, time after partial renal ablation, or dietary protein intake on C/I ratios. Degree of renal ablation did not affect C/I ratios. The results indicated that exogenous creatinine clearance is a valid measure of glomerular filtration rate in both male and female dogs with reduced renal mass.

Mucosa obtained from the cecum of healthy horses and incubated in vitro with 0.1 mM cycloleucine could accumulate this amino acid against an apparent concentration gradient after 60 and 120 minutes. Accumulation by the serosal (antiluminal) surface of the tissue was 3 times greater than accumulation by the mucosal (luminal) surface after 120 minutes (P < 0.001). Cycloleucine accumulation was significantly reduced by Na deprivation after 60 minutes (P < 0.05) and 120 minutes (P < 0.01) and by anoxic conditions after 120 minutes (P < 0.05). Transmucosal flux from mucosal to serosal surface of the tissue was significantly (P < 0.05) greater than the opposing flux, but both unidirectional fluxes were small and were largely attributed to passive processes. It was concluded that the most avid transport system for cycloleucine was on the serosal surface of the horse's cecal mucosa, and an active transport system was not evident on the mucosal surface. An active transport system for amino acids on the serosal surface could be explained by the need for crypt cells, the predominant epithelial cell type in the cecum, to obtain nutrients from blood, rather than from the intestinal lumen.