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Biomedical subjects

J B Stevens

Publications and source records attributed to J B Stevens.

At least 55 records · Page 3Linked to original sources
PubMed1985

Serum selenium concentrations and glutathione peroxidase activities in cattle grazing forages of various selenium concentrations.

In cows from 15 dairy herds (n = 210), serum selenium (Se) concentrations ranged from 0.021 to 0.789 microgram/ml, whereas 0.05 to 0.40 microgram/ml is the reported range for adequate serum Se concentrations in cattle. Serum Se concentrations of dairy cattle appeared to follow a geographic distribution pattern. On the basis of herd mean serum Se concentrations, adequate serum Se concentrations were found in cattle from only 1 of 5 herds grazing forage in the geographic area classified as Se deficient for cattle. Adequate mean serum Se concentrations were found in cattle from 4 of 5 herds located in geographic areas described as having variable forage Se concentrations (Se-marginal areas). Of the 10 herds from these 2 areas, there were only 2 herds in which 95% of the cattle had serum Se concentrations in the Se-adequate range (0.05 to 0.40 microgram/ml). In 2 selected neighboring farms in the Se-deficient area, cattle in 1 herd had adequate serum Se concentrations and cattle in the other herd had less than adequate serum Se concentrations (less than 0.05 microgram/ml). Therefore, more cattle are at risk of developing Se-deficiency disease than is commonly believed and forage of neighboring farms may have different Se concentrations. Serum Se concentrations (up to 0.789 microgram/ml) correlated with glutathione peroxidase enzyme activity; this serum Se concentration (0.789 microgram/ml) is approximately 6.2 times higher than previously reported in dairy cattle. Therefore, RBC glutathione peroxidase activity may be useful in determining the diagnosis of chronic Se toxicosis.

Animal Feed↗
PubMed1984

Iodine toxicosis in six herds of dairy cattle.

Daily iodine intake estimated to range from greater than 68 to 600 mg/animal/day was associated with signs referable to iodine intoxication in adult cows in 6 herds of dairy cattle. Signs were reversed by lowering supplemental intake to less than 12 mg/animal/day. Results of biochemical tests other than those for serum and milk iodine were not diagnostic. Serum iodine concentrations were 2.6 to 6.9 times the mean iodine concentration found in 12 control cows, each receiving 12 mg of iodine/day. Milk iodine concentrations were 3.6 to 13.6 times milk iodine concentrations in the control cows.

Animal Feed↗
PubMed1984

Free fatty acid-induced hypocalcemia in food-deprived dairy cattle.

Food deprivation in 6 dairy cows caused significant increases (P greater than F = 0.0054) in serum free fatty acid concentrations, but did not cause clinically important decreases in serum ionized calcium concentration. Several determinants, including blood pH, serum albumin, and serum bicarbonate were studied as factors that could potentially alter calcium ion concentration. Although several changes were significant, they were small and were not considered to be clinically important in the context of calcium-ion binding. It was concluded that free fatty acid binding of calcium ion did occur, but that such binding did not contribute significantly to the etiopathogenesis of calcium responsive midlactational downer cow syndrome.

Animals↗
PubMed1984

Idiopathic immune complex glomerulonephritis in dogs with multisystem involvement.

Renal specimens obtained by biopsy and/or at necropsy from 4 dogs with nephrotic syndrome were studied using light, immunofluorescence, and electron microscopies. The glomerulonephritis observed in these dogs was considered an idiopathic immune complex glomerulonephritis associated with multisystem involvement because causes of glomerulonephritis in these dogs could not be established. Immunoglobulin A was observed in granular deposits in the mesangial and subendothelial regions of the glomeruli. The relationship of the clinical and pathologic features of this disease in dogs to various renal syndromes in human beings are described.

Animals↗
PubMed1984

Effects of selenium-vitamin E injection on bovine polymorphonucleated leukocytes phagocytosis and killing of Staphylococcus aureus.

Phagocytosis and killing of Staphylococcus aureus by polymorphonuclear leukocytes (PMN) from 8 selenium (Se)-deficient dairy cows from Wisconsin was compared with that in 5 Se-vitamin E injected dairy cows from the same herd. There was no significant difference in the ability of the PMN to phagocytize bacteria. However, PMN of Se-vitamin E injected cows killed the phagocytized bacteria significantly (P less than 0.025) better than did PMN from Se-deficient cows. The defect in the killing capability of PMN of Se-deficient cows might be due to reduced dihydronicotinamide adenine dinucleotide phosphate concentration as a result of diminished glutathione peroxidase activity due to Se-deficiency.

Animals↗
PubMed1984

Influence of reduced protein diets on morbidity, mortality, and renal function in dogs with induced chronic renal failure.

The influence of a maintenance diet containing 44.4% dry weight protein and 2 reduced protein diets containing 8.2% and 17.2% dry weight protein on morbidity, mortality, and renal function of dogs with induced chronic renal failure was studied for 40 weeks. The diets differed in mineral and electrolyte composition in addition to differences in protein, carbohydrate, and fat content. Dogs fed the 44.4% protein diet had a higher mortality (6 of 11) than did dogs fed the 8.2% (1 of 6) or 17.2% (0 of 6) protein diets. Dogs fed the 44.4% protein diet died of uremic complications. An occlusive portal vein thrombus caused death of the nonsurvivor fed the 8.2% protein diet. Clinical signs of uremia were detected only in nonsurvivors fed the 44.4% protein diet. Surviving dogs fed the maintenance diet were less active and had poorer hair than did dogs fed reduced protein diets. Inulin clearance rate and urinary protein excretion were lower in most dogs fed reduced protein diets than in dogs fed the maintenance diet. Despite the greater decrease in renal function, serum urea nitrogen concentrations were markedly lower in dogs fed the 8.2% and 17.2% protein diets than in dogs fed the 44.4% protein diet. Seemingly, the reduced protein renal failure diets were of benefit in preventing or reducing morbidity and mortality associated with the uremic syndrome and in reducing serum urea nitrogen concentrations as compared with that of the higher protein diet. The potential benefits of dietary protein restriction in dogs with chronic renal failure prevailed over potential adverse affects of excessive protein consumption.

Animals↗
PubMed1983

Ectopic pregnancy with uterine horn encapsulation in a cat.

A 4 x 7-cm free-floating cylindrical mass was found in the abdomen of a 2 1/2-year-old domestic short-hair cat at ovariohysterectomy. The left uterine horn was absent. The mass contained 2 necrotic fetuses surrounded by tissue with the histologic appearance of uterine wall.

Animals↗
PubMed1983

Effects of modified protein diets in dogs with chronic renal failure.

A maintenance diet containing 44.4% dry weight protein and 2 reduced protein diets containing 17.2% and 8.2% dry weight protein were studied in dogs with induced chronic renal failure to determine effects on their (1) clinical status, (2) renal function, (3) electrolyte and acid-base balance, (4) divalent ion balance, (5) nutritional status, (6) hematologic status, and (7) hemostasis. A cross-over design of feeding was utilized so that the effect of diet could be studied in each dog at a known state of renal dysfunction and so that reversibility of effects could be determined. The inulin clearance rate was higher when the 44.4% protein diet was fed than when the 8.2% or 17.2% protein diets were fed. However, consumption of lower protein diets was associated with greater physical activity and reduction in serum urea nitrogen concentrations, compared with consumption of the 44.4% protein maintenance diet. Varying degrees of hyperchloremic metabolic acidosis developed in dogs fed the 8.2% and 17.2% protein diets. Reduced total serum protein and albumin concentrations, and hypercholesterolemia developed in dogs fed the 8.2% protein diet. All effects were reversible after diets were changed. It was concluded that diet-induced alterations in renal function associated with moderate dietary protein restriction did not adversely effect clinical and biochemical status of dogs with renal failure. It was unclear whether the clinical and biochemical changes observed with more severe protein restriction resulted from diet-induced changes in renal function.

Animal Feed↗
PubMed1983

Suspected villonodular synovitis in a dog.

Progressive bilateral juxta-articular osteolytic lesions were detected in the coxofemoral joints of a dog. The differential diagnoses included neoplasia or an inflammatory process of periarticular tissue. The clinical signs, radiographic findings, and gross and microscopic appearance of the lesions were similar to the inflammatory changes of villonodular synovitis.

Animals↗
PubMed1983

Influence of modified protein diets on the nutritional status of dogs with induced chronic renal failure.

The influence of a canine maintenance diet containing 44.4% protein (dry weight) and 2 reduced-protein renal-failure diets containing 8.2% or 17.2% protein (dry weight) on the nutritional status of dogs with induced chronic renal failure was evaluated for 40 weeks. Nutritional status was assessed by changes in serially determined body weights, hindlimb circumferences, serum protein concentrations, complete blood cell counts, serum cholesterol concentrations, glucose tolerance tests, and blood glucose concentrations. Evidence of suboptimum nutritional status was observed in dogs fed the 8.2% or 44.4% protein diets, but not in dogs fed the 17.2% protein diet. Only a small reduction in hindlimb circumference developed in dogs fed the 17.2% protein diet. Reduced body weight and hindlimb circumference and normocytic normochromic anemia developed in dogs fed the 44.4% protein diet. Reduced body weight and hindlimb circumference, hypoalbuminemia, hypoproteinemia, hypercholesterolemia, and normocytic normochromic anemia developed in dogs fed the 8.2% protein diet. A beneficial effect of moderate dietary protein restriction (17.2% protein) on the nutritional status of the dogs was observed. In contrast, excessive intake or restriction of dietary protein was associated with detrimental effects.

Animals↗
PubMed1983

Complications of retrograde contrast urethrography in dogs and cats.

Urinary bladder lesions varying histologically from a focal hemorrhagic cystitis to a diffuse transmural fibrinonecrotic cystitis were encountered in 11 of 14 dogs and cats euthanatized 1 day after retrograde urethrography. Focal-to-diffuse hemorrhagic urethritis was histologically encountered in 14 of 14 dogs and cats euthanatized 1 day after retrograde urethrography. Lesions in the urinary bladder and urethra were not reversible within 14 days and were evident histologically in 10 of 15 urinary bladders and 11 of 15 urethras of dogs and cats euthanatized 14 days after retrograde urethrography. During urethrography, iatrogenic mural leakage of contrast media into the bladder wall or bladder wall rupture was encountered radiographically in 6 of 15 dogs and 3 of 14 cats. However, macroscopic evidence of bladder rupture was encountered in only 1 male dog at necropsy. Immediately after retrograde urethrography, macroscopic hematuria occurred in 12 of 15 dogs and 9 of 14 cats. Microscopic hematuria was not encountered in dogs or cats euthanatized 14 days after urethrography. Pyuria was encountered less frequently and was present in only 2 cats euthanatized 14 days after urethrography. One day after urethrography, urinary tract infection characterized by urine cultures with greater than 10(5) microbes/ml was encountered in 4 of 29 dogs and cats. All animals with urinary tract infection were female dogs or cats. At day 14, only 1 female cat had a positive urine culture. Seemingly, the technique of retrograde urethrography was the cause of the encountered lesions.

Animals↗
PubMed1983

Effects of prolonged distention of retention catheters on the urethra of dogs and cats.

The effects of inflation of a balloon-tipped catheter in the distal part of the urethra of clinically healthy male and female dogs and cats were evaluated. Tissues were evaluated at 1 and 14 days after balloon inflation. Macroscopic and microscopic lesions were limited to the distal part of the urethra occupied by the inflated balloon in animals which were euthanatized 1 day after balloon inflation. The lesions were characterized by submucosal urethral hemorrhage. This investigation indicates that balloon inflation for 15 minutes duration in the distal part of the urethra of dogs and cats results in a mild reversible inflammatory reaction.

Animals↗
PubMed1982

Evaluation of renal biopsy in 197 dogs and cats.

A retrospective study of needle biopsy of the kidney of 163 dogs and 34 cats was performed to evaluate its clinical value and postbiopsy complications. Complications included microscopic hematuria (41 of 53 cases in which urinalyses were performed within 48 hours following the biopsy), gross hematuria (4 dogs), and hydronephrosis (3 of 82 dogs and 1 of 19 cats necropsied). Satisfactory needle biopsy specimens were obtained by use of Franklin-Silverman, Metcoff, and true-cut needles. The necropsy diagnosis matched the biopsy diagnosis in 80 of 82 dogs necropsied and in 17 of 19 cats necropsied.

Animals↗
PubMed1982

Canine cutaneous lymphoma.

Cutaneous lymphoma (mycosis fungoides) was diagnosed by multiple biopsies of nonulcerated cutaneous lesions in 13 dogs. The disease was initially characterized by erythema and alopecia of the trunk. Subsequently severe scaling, pruritus, and skin nodules developed. Lymph nodes were usually normal in size during early stages of the disease but became enlarged as the disease became extensive. Four dogs were treated with cytotoxic drugs. Marked improvement of skin lesions occurred in 3 dogs, but treatment did not prevent development of extra-cutaneous lesions.

Animals↗
PubMed1982

Influence of modified protein diets on electrolyte, acid base, and divalent ion balance in dogs with experimentally induced chronic renal failure.

The influence of a maintenance diet (44.4% dry weight protein) and 2 reduced protein diets (8.2 and 17.2% dry weight protein) on acid-base, electrolyte, and divalent ion balance of dogs with experimentally induced chronic renal failure was studied for 40 weeks. Moderate-to-severe hyperchloremic metabolic acidosis developed in dogs fed the 8.2% protein diet, but not in the groups fed the 17.2% and 44.4% protein diets. Serum sodium and potassium concentrations were not altered significantly by the diets. Mean serum calcium concentrations increased significantly in the 3 groups after renal failure was induced; however, serum calcium concentration generally did not exceed the normal range. Dogs fed reduced protein diets had smaller serum magnesium and phosphorus concentrations than did the dogs fed the maintenance diet. Microscopic alterations in bone morphology consistent with canine renal osteodystrophy were not detected after 40 weeks of renal failure in dogs fed the 17.2% and 44.4% protein diets. Examination of skull radiographs of the dogs prepared 40 weeks after renal failure was induced revealed that the lamina dura dentes were visible in all groups. It was concluded that the 8.2% protein diet was of therapeutic benefit in management of altered divalent ion metabolism in dogs with chronic renal failure. However, the high frequency of concomitant acidosis indicated that appropriate alkalinization therapy should be included with this diet. Adverse effects of feeding the 17.2% protein diet were not detected. However, it was less effective than the 8.2% protein diet in minimizing development of hypermagnesemia and skeletal changes consistent with renal osteodystrophy.

Acid-Base Equilibrium↗
PubMed1982

Model infection of the chicken embryo with Haemophilus somnus.

Infectious thromboembolic meningoencephalitis of cattle which is caused by Haemophilus somnus has been difficult to study due, in part, to lack of model infection in a laboratory animal. Model infection was induced in 12-day-old chicken embryos after IV injection of H somnus. Death with typical lesions (hemorrhage, degeneration of brain, congestion of venules with leukocytes and meningitis) was seen in the chicken embryo between 2 and 6 days after injection of organisms. Bacteria could be demonstrated in lesions, using Warthin-Starry silver strain. Three stable colonial variants of H somnus were cultured from dead embryos. They appeared as small translucent (ST), small opaque (SO), and large opaque (LO). Lethal dose50 values of ST was 4.4 x 10(4); for SO, 3.6 x 10(4); and for LO, 8 x 10(6). Statistical analysis indicated that ST and SO were significantly more lethal (P less than 0.001) than LO.

Animals↗