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Biomedical subjects

W A Crowell

Publications and source records attributed to W A Crowell.

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

Characterization of magnesium-induced urinary disease in the cat and comparison with feline urologic syndrome.

Aggregates of struvite crystals caused urethral obstruction in a high percentage of cats fed moist and dry diets supplemented with Mg oxide. Some of the diets were associated with cystolith formation as well. The percentage of Mg in the experimental diets was a misleading indicator of Mg intake because of differences between moist and dry diets in their caloric density. Magnesium homeostasis was maintained in cats ingesting large quantities of Mg. Tissue (kidney, muscle, and rib) concentrations of Mg were the same in cats fed high Mg and control diets. Plasma Mg concentration was increased only in cats ingesting the largest amount of Mg. Magnesium homeostasis was maintained by a marked increase in urine Mg excretion. However, urine Mg concentration was not directly related to Mg intake, apparently because of differences between diets in intestinal absorption of Mg. Urethral obstruction of experimental cats was not associated with a transient increase in Mg intake, nor did obstructing cats have higher urine Mg concentrations than did nonobstructing cats fed the same diet. This observation indicates that factor(s) other than urine Mg concentration are important in urethral obstruction. Cats with urethral obstruction due to naturally occurring disease, feline urological syndrome (FUS), had markedly lower urine Mg concentrations than cats fed high Mg diets. This finding refutes the theory that cats develop FUS because of primary Mg hyperabsorptive phenomena or because of a primary urinary leak of Mg. It also indicates that factors other than urine Mg concentration are involved in the genesis of naturally occurring urethral obstruction. Another difference between the natural and the induced disease was related to the character of the urinary precipitates. Experimental diets higher in Mg concentration caused urolith formation, which is uncommon with FUS. Lower Mg diets caused obstruction with aggregates of crystals, but mucus was not observed. However, in the experimental disease induced in the present study, urinary precipitates were predominantly or exclusively struvite, as has been reported in the natural disease. Many similarities were seen between the diet-induced disease and FUS, but factors in addition to Mg intake are involved in the natural disease. The importance of Mg, compared with the undefined factors, remains to be established.

Animals↗
PubMed1985

Effects of three diets on dogs with induced chronic renal failure.

Healthy mixed-bred dogs of both sexes had renal mass surgically reduced and were allowed 2 to 3 months for hypertrophy of the remnant kidney. They were then allotted into 3 groups with equal renal function and were fed 1 of 3 diets that differed in composition. Group 1 dogs (n = 6) were fed moist food that contained 50% protein, 2.34% Ca, and 1.64% P with a P-binding agent (basic aluminum carbonate gel) added. Group 2 dogs (n = 6) were fed a dry diet that contained 24.5% protein, 1.26% Ca, 1.21% P, and the same P-binding agent as used for group 1. Group 3 dogs (n = 7) were fed a moist diet that contained 16.1% protein, 0.38% Ca, and 0.3% P without a P-binding agent. Each group was fed its diet for 92 days and monitored for responses. Mortality associated with uremia occurred in 2 of 6 group 1 dogs, 0 of 6 group 2 dogs, and in 2 of 7 group 3 dogs. Among survivors, clinical signs were seen in the more azotemic dogs of group 1, but not in dogs of groups 2 and 3. The blood urea nitrogen, plasma P concentrations, and PCV values were most favorable in group 3 and least favorable in group 1. Marked differences between groups were not seen in plasma concentrations of protein, albumin, or Ca or in plasma alkaline phosphatase activity. Values for glomerular filtration rate did not change in any group during the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Morphometric studies of the bovine uterus: microscopic lesions and retrospective reproductive history.

A survey of reproductive tracts from nonpregnant cows at an abattoir was conducted. Reproductive tracts from 98 cows were studied microscopically and evaluated with a grading system to determine the severity of pathologic changes. Inflammatory reaction (type and distribution), fibrosis, gland morphology, and appearance were measured, quantified, and scored (1 to 4). Category 1 endometrium (normal) was found in 18 cows, category 2 in 23, category 3 in 34, and category 4 in 23. The category of endometrium was then compared with the retrospective reproductive status, and it was found that reproductive problems had occurred in 6 cows (33.3%) in category 1, in 13 cows (56.5%) in category 2, in 25 cows (73.5%) in category 3, and in 21 cows (91.3%) in category 4. Cervicitis was found in 43 (43.8%) genital tracts; 16 cows (16.3%) had salpingitis. Ovarian lesions were not observed. Serum samples were tested for certain antibodies. Only 1 was seropositive for brucellosis, but 61 of 81 sera had leptospira titers greater than 1:100 and 1:50 (hardjo). The serovar hardjo was the most prevalent. All sera had neutralizing titers against parainfluenza type 3 virus; 74.2% and 56.7% of the sera had neutralizing antibodies against bovine viral diarrhea virus and infectious bovine rhinotracheitis virus, respectively.

Animals↗
PubMed1984

Pelvic bladder in dogs without urinary incontinence.

Double-contrast cystography was performed simultaneously with cystometrography in 6 male and 6 female dogs. All dogs were continent, and results of urinalyses were normal. Initial radiographs were made following intravesical infusion of 0.88 ml of positive contrast medium/kg of body weight. Additional radiographs were made during infusion of CO2. The last radiographs were made at the time of detrusor reflex (11 dogs) or when intravesical pressure reached 50 cm H2O (1 female). An average of 34% (range, 11% to 67%) of bladder length was within the pelvic canal when only the positive contrast medium was infused into the bladders. By the end of CO2 infusion, the bladder neck was more cranially located in 5 of 6 males and in 5 of 6 females. On the last radiographs made, an average of 19% (range, 10% to 35%) of bladder length was within the pelvic canal in 3 of 6 males and in 4 of 6 females. The bladder neck was rounded in 10 of 12 dogs. Thus, it was concluded that previous reports associating pelvic urinary bladder with urinary incontinence and other urologic abnormalities are questionable.

Animals↗
PubMed1984

Cystometry in dogs under oxymorphone and acepromazine restraint.

Cystometry was performed in 12 dogs under oxymorphone and acepromazine restraint. A detrusor reflex occurred in 10 of 12 dogs (83%). Mean threshold pressure and volume were 31 cm H2O and 22 ml/kg, respectively. Tonus limb II varied inversely with threshold volume. Threshold volume varied directly with body weight; threshold pressure was independent of body weight.

Acepromazine↗
PubMed1984

Clinical aspects of experimentally induced chloride deficiency in Holstein calves.

A severe total body chloride deficit was induced in Holstein calves by feeding a low-chloride ration (0.063% Cl) and removing digesta daily from the abomasum through a surgically implanted cannula. Clinical signs of the deficit observed included polydipsia, polyuria, dehydration, anorexia, scleral injection, decreased respiratory rate, and blood and mucus in the feces. Necropsy findings included dehydration, blood in the lumen of the small intestine, and renal lesions. The most extensive histopathologic changes occurred in the renal tubular epithelium of the outer medulla where mineralization of the tubular epithelium and basement membranes was frequently seen.

Animals↗
PubMed1982

Acute aflatoxicosis in swine: clinical pathology, histopathology, and electron microscopy.

Feeder pigs weighing 12 to 15 kg each were given a single oral dose of aflatoxin, 1.2 mg/kg of body weight. Liver-specific serum enzyme activities were compared with gross, microscopic, and ultrastructural hepatic changes in individual pigs euthanatized at 24, 48, and 72 hours after they were given aflatoxin. The greater the morphologic change in liver of the treated pigs, the greater the increase in liver-specific serum enzyme activities. Isocitric dehydrogenase, alkaline phosphatase, sorbitol dehydrogenase, and aspartate aminotransferase activities increased in 6 of 8 treated pigs by 24 hours. Increase in gamma-glutamyl transpeptidase activity was not significant. Microscopic and ultrastructural changes in centrilobular hepatocytes included glycogen deletion, mitochondrial and endoplasmic reticulum swelling, membrane disruption, and nuclear fragmentation at 24 hours. The centrilobular areas had marked extravasation of erythrocytes at 24 hours without basal lamina changes. At 72 hours, the centrilobular hepatocytes had increased lipid vacuoles and acceptable amounts of glycogen. Marked infiltrations of monocytes, plasma cells, and lymphocytes were also present at this time.

Alkaline Phosphatase↗
PubMed1982

High performance liquid chromatographic determination and clearance time of aflatoxin residues in swine tissues.

Liver, kidney, and muscle tissues from swine given a single oral dose of 1.2 mg aflatoxins/kg body weight and from young pigs fed an aflatoxin-contaminated diet (0,400, or 800 ng/g feed) for 10 weeks were analyzed for aflatoxin residues. Extraction was performed according to the method of Stubblefield and Shotwell. Aflatoxin residues were detected by high performance liquid chromatography (HPLC), and residue levels were correlated with withdrawal times. Residues were present in liver and kidney but not muscle by 12 h post-dosing; residues were detected in muscle by after 24 h. Residue levels decreased over the 72 h period in all tissues. No aflatoxin residues were detected in the muscle from any pig 72 h post-dosing or in those pigs fed the 400 ng/g diet, but were present in the muscle of pigs fed the 800 ng/g diet.

Aflatoxins↗
PubMed1982

Effect of dietary phosphorus restriction on the kidneys of cats with reduced renal mass.

Cats with reduced renal mass were fed a phosphorus-restricted diet (0.24% P, dry weight) or a normal phosphorus diet (1.56% P, dry weight) for 6 5 to 343 days. Renal function was determined biweekly by blood urea nitrogen and plasma creatinine measurements and by initial and terminal inulin clearance procedures. Neither diet caused a significant change in renal function during the study. However, histologic examination of kidneys obtained at necropsy clearly separated the cats on the basis of dietary phosphorus. The kidneys from cats fed the normal phosphorus diet had mineralization, fibrosis, and mononuclear cell infiltration, whereas the kidneys from cats fed the phosphorus-restricted diet had little or no changes.

Animal Feed↗
PubMed1981

Neomycin toxicosis in calves.

Calves (n = 4) were given neomycin (2.25 or 4.5 mg/kg) twice daily IM and were compared with 2 calves given penicillin IM. The 2 hallmarks of aminoglycoside toxicosis, nephrotoxicosis and ototoxicosis, were seen with both dosages of parenterally administered neomycin. Nephrotoxicosis was confirmed by abnormal findings in urinalysis (granular casts, proteinuria, low specific gravity), renal biopsy results (tubular degeneration and necrosis), and increased 24-hour amounts of urinary enzymes (alanine aminopeptidase and gamma-glutamyltranspeptidase). Azotemia, decreased creatinine clearance, polyuria, and polydipsia also were documented in calves given neomycin. Clinically, deafness was suspected in 2 calves and was documented by electrical auditory-evoked response tests. Abnormalities in partial thromboplastin times and renal residues of neomycin were seen in all 4 calves that were given neomycin, but not in calves that were given penicillin.

Alanine Transaminase↗
PubMed1981

Pathological changes in kidneys, livers and spleens of Brugia pahangi-infected jirds (Meriones unguiculatus).

The major organs, other than lymphatics, of jirds (Meriones unguiculatus) with prepatent and chronic patent infections of Brugia pahangi were studied by standard histological, electron microscopical and fluorescent antibody techniques. Changes observed and not previously described in detail or in large numbers of animals are reported. Multifocal non-suppurative interstitial nephritis was observed in 4% on animals with patent infections of 163 days duration and in 69% of animals with patent infections of 274 days duration. Glomerular changes were not observed in kidneys of any animals infected with B. pahangi. The occurrence of large granulomata composed of lymphocytes, macrophages, eosinophils and giant cells in the liver and smaller granulomata in the spleen correlated with patency of infections but microfilariae or worm antigens were not observed in these areas. Amyloid deposits were demonstrated in the spleen of 4% of animals with patent infections of 163 days duration and in 38% of animals with patent infections of 274 days duration but were not seen in uninfected animals of the same age or animals receiving only challenge inoculations of 28 days duration.

Amyloid↗
PubMed1981

Renal function after prolonged hypotensive anesthesia and surgery in dogs with reduced renal mass.

The effect of prolonged hypotensive anesthesia and surgery on renal function was studied in 8 dogs with decreased renal mass. Renal mass was reduced by unilateral nephrectomy and ligation of 4 of the 6 terminal renal artery branches of the opposite kidney. One week after reduction in renal mass, the dogs were azotemic with a serum urea nitrogen (SUN) value of 65.8 +/- 11.5 mg/dl. Glomerular filtration rate, as estimated by 14C-inulin clearance, was 0.66 +/- 0.19 ml/kg of body weight/hour. A mean arterial pressure of less than 75 mm of Hg was maintained for 4 hours in dogs given 2.3 +/- 0.7% halothane. An exploratory laparotomy lasting 1 hour was performed. The day after the hypotensive episode, 3 dogs began vomiting, became dehydrated, and had SUN values greater than 100 mg/dl. The SUN values returned to base-line values after the dogs were rehydrated. Eight days after the hypotensive episode, 14C-inulin clearance decreased 15.2 +/- 8.2% (P less than 0.005) compared with base-line clearance values. Light microscopic and electron microscopic observations of the kidneys did not demonstrate acute renal failure. Prolonged hypotensive anesthesia can cause a decrease in renal function, and may cause prerenal uremia and/or acute renal failure.

Anesthesia, Inhalation↗
PubMed1981

Experimental aflatoxicosis in swine: morphological and clinical pathological results.

The morphological changes in livers of 30 feeder pigs fed diets containing corn contaminated by aflatoxins (0.0 microgram aflatoxins/g feed, 0.4 microgram aflatoxin/g feed, and 0.8 microgram aflatoxin/g feed) were compared with changes in hematology, liver specific serum enzymes, serum proteins, and lymphocyte stimulation indices. Histologically, the livers were classified into five groups. Pigs fed the 0.8 microgram/g diets had the most severe histological lesions of karyomegaly, bile ductule proliferation and hepatocellular degeneration plus elevated gamma-glutamyl transpeptidase, aspartate aminotransferase, and alkaline phosphatase. This group also had significantly lower total protein and albumin values compared to the control pigs. Variation in the severity of the histological lesions was seen in pigs fed 0.4 microgram/g diets as well as variation in lymphocyte indices, liver specific serum enzymes, and electrophoretic results in the affected pigs in that group.

Aflatoxins↗
PubMed1979

Polycystic renal disease in related cats.

Six kittens from four litters of related cats had greatly enlarged abdomens and died before they were 7 weeks old. Kittens from two litters were necropsied and found to have bilateral polycystic renal disease and cystic bile ducts.

Animals↗