Histomorphometry of the optic nerves of normal dogs and dogs with hereditary glaucoma

The beagle dog with hereditary primary open-angle glaucoma, unlike other animal models of human glaucoma, possesses a slowly progressive, sustained elevation of intraocular pressure. The effects of this insidious elevation in intraocular pressure on the axons of the optic nerves of three beagles at early stages of glaucoma and two beagles with advanced signs of glaucoma were compared to the optic nerves of four age-matched normal dogs. Plastic embedded optic nerve cross-sections (1 micron) 1 mm posterior to the lamina cribrosa were osmicated and stained with Toluidine Blue. Axons from 0.2 to > 2.0 microns in diameter were counted and measured in 16 cross-sectional regions of equal size within the whole optic nerve using a computerized image analysis system. The mean optic nerve axon diameters in the normal, early glaucomatous, and advanced glaucomatous dogs were 1.53, 1.25 and 1.13 microns respectively. The average total optic nerve axon count in the normal dogs was 148,303. Approximately 16% of the total axonal fibers were counted in each nerve. The counts of optic nerve axons 2.0 microns or greater in diameter were reduced by up to 60% in the central regions of the optic nerves of affected beagles. The large diameter axons of the peripheral optic nerve of the beagle dogs with glaucoma were more resistant to the elevated intraocular pressure. The counts of axons > 0.6 to 0.8 micron in diameter were significantly increased in glaucomatous beagles.     

Gastric A-cell function in normal dogs

Glucagon release from the gastric fundus and pancreas were compared in normal dogs by measuring glucagon in plasma from a major gastroepiploic vein, the superior pancreaticoduodenal vein, and the inferior vena cava. In 32 dogs in the basal state, gastric vein glucagon averaged 97 +/- 40 pg/ml, not significantly different from the 93 +/- 41 pg/ml level in the vena cava. Pancreaticoduodenal vein glucagon averaged 250 +/- 32 pg/ml (P less than 0.001). Intravenous arginine infused in four dogs caused a rise in mean gastric vein glucagon to 210 +/- 33 pg/ml within 3 min, and glucagon remained between 53 and 98 pg/ml above the vena caval level thereafter. In the gastric vein, the rise in glucagon was significantly greater than in the vena cava at 3, 5, and 10 min (P less than 0.05), but was far less than in the pancreaticoduodenal vein where glucagon rose to 1,295 +/- 379 pg/ml at 1.5 min. Evidence of modest gastric glucagon release was observed after the intragastric instillation of arginine, but not during insulin or phloridzin-induced hypoglycemia. It was concluded that in normal dogs under the circumstances studied, the gastric fundus is not a major source of circulating glucagon.     

Variability of ciliary ultrastructure in normal dogs

The incidence of abnormal tracheal cilia from each of seven normal healthy dogs was estimated using samples prepared for TEM and SEM from the dorsal, lateral, and ventral aspects of the 3rd, 12th, and 24th tracheal rings. Some samples were demembranated with Triton X-100 and stained with tannic acid to visualize microtubular protofilaments. From each region of each ring of each dog on which TEM was done, 500 transversely sectioned cilia were observed, 27,000 cilia overall. Abnormal numbers of central microtubules and abnormal numbers of peripheral microtubules occurred in all samples in about 2% of all cilia. Compound cilia were consistently observed in samples from the 3rd ring and were not observed in any samples from the 24th ring. Therefore, before abnormal ciliary ultrastructure may be associated with disease, the rate of occurrence must exceed that in appropriate control individuals. Additionally, compound cilia, which have previously been associated with a variety of diseases, obviously occur in normal individuals; however, their observation may be a function of biopsy site selection.     

Duration of QT interval in clinically normal dogs

The QT interval is the period from onset of the QRS complex to the end of the T wave. The QT interval is useful for monitoring drug (eg, quinidine) and electrolyte (eg, calcium) effects on the heart. It depends principally on heart rate (HR), and the relationship between QT interval and HR has been expressed for human beings and for dogs. The purpose of the study reported here was to quantify that relationship for dogs and to assess whether body weight also influenced QT interval. The ECG was recorded from 17 dogs, ranging in weight between 7 and 25 kg. Dogs were anesthetized with fentanyl/droperidol/ketamine, and HR was accelerated by administration of graded doses of atropine. A significant relationship was not found between QT interval and body weight. Despite changes in HR during sinus arrhythmia, a significant relationship was not found between QT and RR intervals. The QT interval vs HR accelerated by atropine was analyzed for all dogs and for small (7 to 10 kg, n = 5), medium (10 to 20 kg, n = 7), and large dogs (20 to 25 kg, n = 5). Equations relating QT interval to mean HR were calculated for each group. Our data may serve as a baseline with which to compare QT intervals from dogs with heart disease and/or electrolyte imbalance.     

Urinary excretion of amino acids in normal and cystinuric dogs

The 24-h urine excretion of 20 amino acids was investigated in 24 cystinuric and 15 normal dogs. The diagnosis of cystinuria was based on infrared spectroscopy of removed uroliths, which in all cases were composed of pure cystine. Seven of 24 cystinuric dogs showed normal cystine excretion compared to normal dogs, and four of 24 dogs showed normal total amino acid excretion. In contrast to earlier investigations, almost half of the cystinuric dogs (46%) showed elevated excretion of five or more amino acids. Isolated cystinuria, or isolated dibasic amino aciduria was not found. Compared to normal dogs, the cystinuric dogs showed a significantly (P < 0.05) increased excretion of cystine, arginine, lysine, cystathionine, glutamic acid, threonine and glutamine. There was a significant correlation (P < 0.05) between the urinary excretion of cystine and 10 other amino acids, with the highest correlation found (P < 0.001) for arginine, lysine, cystathionine, ornithine and 1-methyl-histidine. Three patterns of amino acid excretion could be identified: (1) increased excretion and a significant correlation with cystine for the three dibasic amino acids (lysine, arginine and ornithine), compatible with a common reabsorption mechanism as shown in man. This pattern was also found for cystathionine and glutamic acid, which might indicate a relation in metabolism or transport; (2) increased excretion but no correlation with cystine for glutamine, threonine and citrulline; (3) good correlation with cystine, but no increased excretion for 1-methyl-histidine, phenylalanine, 3-methyl-histidine, leucine and alanine. The great variation in urinary cystine excretion suggests that factors other than the excretion of cystine must be considered as causes of cystine urolith formation. For example, cystinuric dogs were found to have lower diuresis than normal dogs and produced urine with higher cystine concentration thereby increasing the risk of cystine urolith formation.     

Allergen-specific IgE and IgGd antibodies in atopic and normal dogs

Intradermal skin tests (IDSTs) were performed on 65 atopic and 24 normal dogs. The levels of allergen-specific IgE and IgGd antibodies were determined in serum samples by enzyme-linked immunosorbent assay (ELISA) using the same 12 allergens that were used in the IDST on normal dogs. The correlation between the levels of IgE and IgGd to Dermatophagoides farinae (DF) and Dermatophagoides pteronyssinus (DP) was examined. The sensitivity, specificity and positive and negative predictive values of allergen-specific IgE and IgGd levels in the total dog population were also compared. Results were consistent and reproducible for 9/12 allergens, but in the case of house dust, flea and Alternaria tenuis, a less discriminating standard curve and the fact that the negative control gave positive results, suggests non-specific binding and that these allergens are complex and should not be employed without further purification. A high percentage of atopic dogs had positive IDSTs and detectable IgE and IgGd antibodies to DF, DP and house dust. Similar results were obtained in the normal dog population. There were significant correlations between allergen-specific IgE and IgGd levels to DF and DP. However, in contrast to IgE, allergen-specific IgGd in normal dogs was higher than in atopic dogs. Furthermore, a high percentage of the atopic population had detectable IgGd to unrelated allergens, despite negative IDSTs. Overall, the negative predictive values were similar for both IgE and IgGd. Sensitivities were higher in the allergen-specific IgGd assays, but the specificities and positive predictive values were higher in the allergen-specific IgE assays. In conclusion, the concordance of IDSTs with ELISA results to DF and DP in normal dogs without clinical signs implied the possible heterogeneity of IgE in dogs. The presence of IgGd directed against apparently irrelevant allergens in atopic patients and the high levels of IgGd in normal dogs to the most common allergens, DF and DP, implied an uncertain role of IgGd in canine atopic disease. Therefore, the detection of allergen-specific IgE is a more useful adjunct to the diagnosis of atopic disease in the dog than IgGd.     

What constitutes a normal seminal analysis? Semen parameters of 243 fertile men

A cross-sectional study was conducted to determine the semen parameters (i.e. volume, concentration, motility, viability and normal morphology) of proven fertile males in Singapore and compare it with the World Health Organization (WHO) recommended normal values and to examine some factors that may affect spermatogenesis. A total of 243 men, whose wives were pregnant at the time of collection of semen, provided a semen sample each after sexual abstinence for 3 days. A questionnaire was used to elicit occupational exposure, alcoholic consumption, smoking history and past significant medical history. Most subjects had normal sperm volume (56.4%), concentration (79.8%), motility (69.5%) and viability (53.5%) based on WHO criteria. However, fertile men had a low mean percentage of normal sperm morphology (20.0%), although they were normally distributed. Cigarette smoking was associated with significantly lower semen volumes even after adjusting for alcohol consumption. The sperm parameters (i.e. volume, density, motility, viability and normal morphology) were not significantly associated with ethnic differences. The WHO criterion for normal sperm morphology is too stringent, and should be adopted with caution. Normal sperm morphology is but one of many parameters for assessment of fertility. Social alcohol consumption, cigarette smoking, and 'recent fever' did not appear to affect sperm quality in this group of fertile men.     

Electrocardiographic characteristics of endurance-trained Alaskan sled dogs

OBJECTIVE: To determine electrocardiographic characteristics of endurance-trained Alaskan sled dogs. DESIGN: Case series. ANIMALS: 319 Alaskan sled dogs entered to compete in the 1994 Iditarod Trail Sled Dog Race. PROCEDURE: ECG were recorded while dogs were standing and were analyzed digitally. RESULTS: Amplitudes of P waves (median, 0.40 mV; fifth to 95th percentile range, 0.11 to 0.61 mV) and R waves in lead II (median, 3.02 mV; fifth to 95th percentile range, 1.49 to 4.40 mV) were high; durations of P waves in lead II (median, 61 milliseconds; fifth to 95th percentile range, 36 to 96 milliseconds), QRS complexes (median, 64 milliseconds; fifth to 95th percentile range, 52 to 80 milliseconds), and QT intervals (median, 236 milliseconds; fifth to 95th percentile range, 208 to 277 milliseconds) were prolonged. Median value for mean axis of ventricular depolarization was 57 degrees (fifth to 95th percentile range, 19 to 90 degrees). Atrial and ventricular premature depolarizations were observed in 3 (0.9%) and 4 (1.3%) of 319 dogs, respectively, and paroxysmal ventricular tachycardia was detected in 1 (0.3%). CLINICAL IMPLICATIONS: Results suggest that electrocardiographic characteristics of endurance-trained Alaskan sled dogs differ from those reported for nonsled dogs, probably as a result of effects of endurance training on heart size. Some of these characteristics could be mistaken as evidence of pathologic cardiac hypertrophy.     

Parenteral anticholinergics in dogs with normal and elevated intraocular pressure

Dogs given parenteral anticholinergic drugs have been thought to be at risk for development or exacerbation of elevated intraocular pressure (IOP). In a randomized, blinded, placebo-controlled study, we evaluated the effect of intramuscular glycopyrrolate (0.01 mg/kg) on pupil diameter and IOP in unanesthetized normal dogs. Treatment with glycopyrrolate did not change pupil diameter or IOP from baseline, nor were there differences between glycopyrrolate and saline-treated (control) dogs. In addition, the authors retrospectively reviewed the medical records of 2,828 dogs undergoing general anesthesia between April 1987 and September 1990 to determine if there was an association between parenteral anticholinergic medication and postanesthetic elevation in IOP. The authors also determined the frequency of bradycardia requiring anticholinergic therapy during anesthesia in dogs with glaucoma. Of the 2,828 cases reviewed, the records of 46 dogs coded for glaucoma were examined in detail. The 46 dogs underwent 62 episodes of anesthesia, with 23 episodes including exposure to an anticholinergic drug. An increase in IOP from preanesthetic to postanesthetic measurement occurred in three dogs. One of these dogs received anticholinergic medication for bradycardia during anesthesia. The postanesthetic elevation in IOP in this dog was probably not drug related. Preanesthetic anticholinergic administration did not affect the incidence of anticholinergic administration for bradycardia during the anesthetic episode. Anticholinergic therapy during anesthesia was more frequent when the preanesthetic medication included an opiate drug. These studies do not indicate an association between parenteral anticholinergic administration and elevations in IOP.     

Semen characteristics, endocrine profiles, and testicular biopsies of infertile men of different ages

This investigation was conducted to evaluate the interaction among semen characteristics, endocrine profiles, and testicular biopsies in 968 infertile men. Men were divided into five groups according to age. Sperm with abnormal morphology and percentage of progressive motility were found in patients over 40 years of age. However, there was a remarkable heterogeneity of semen characteristics within the examined groups. Azoospermia was present in 43 patients (4%), oligozoospermia in 73 (7%), and polyzoospermia in 126 (13%). Sexually transmitted disease was found in 28%. It would appear that age contributed to the decline in semen quality in men over 40 years old.     

Human c-yes-1-related proto-oncogene in clinically normal dogs

Human c-yes-1-related canine proto-oncogene in genomic DNAs from 21 clinically normal dogs was analyzed by Southern blot hybridization. The present study indicated that this proto-oncogene was well conserved in clinically normal dogs, however, there were structural changes in some dogs. These changes were different in each individuals and detected in low frequency.     

Effects of iatrogenic blood contamination on results of cerebrospinal fluid analysis in clinically normal dogs and dogs with neurologic disease

OBJECTIVE: To examine the effects that iatrogenic blood contamination would have on total protein concentration and nucleated cell count in CSF from clinically normal dogs and dogs with neurologic disease. DESIGN: Case-control study. STUDY POPULATION: 53 dogs confirmed to have neurologic disease and 21 clinically normal dogs. PROCEDURE: CSF samples were obtained from the cerebellomedullary cistern or the lumbar portion of the subarachnoid space. Red blood and nucleated cell counts were determined, and protein concentration was measured. RESULTS: RBC count was not significantly correlated with nucleated cell count or protein concentration in clinically normal dogs or dogs with neurologic disease. CLINICAL IMPLICATIONS: High CSF nucleated cell counts and protein concentrations are indicative of neurologic disease, even if samples contain moderate amounts of blood contamination.     

Comparative study of determined biochemical parameters in semen of vasectomized and non-vasectomized subjects

OBJECTIVE: Biochemical parameters, fundamentally those of prostatic origin, were analyzed and compared to determine the semen composition of vasectomized and non-vasectomized subjects. METHODS: 100 ml of semen from each group (vasectomized and non-vasectomized) were obtained. After thawing, the pool was homogenized and 5 one-ml sample from each one were analyzed for the following biochemical parameters: gamma glutamyl transferase (GGT), lactic dehydrogenase (LDH), prostate acid phosphatase (PAP), prostate-specific antigen (PSA) and total protein (TP) in the seminal plasma. Determination of the foregoing biochemical parameters was performed automatically with autoanalyzers. RESULTS: The mean values for the vasectomized and non-vasectomized groups were respectively: a) GGT: 8890 +/- 811 and 5714 +/- 403 IU/L; b) LDH: 7045 +/- 879 and 2465 +/- 339 IU/L; c) PAP: 2,099,000 +/- 330,764 and 1,860,000 +/- 302,138 ng/ml; d) PSA: 953,000 +/- 154,715 and 1,018,000 +/- 119,685 ng/ml; total protein: 39,860 +/- 1094 and 37,900 +/- 5606 micrograms/ml. CONCLUSIONS: Analysis of the different biochemical parameters showed no statistically significant differences between the mean values for PAP, PSA and total protein for the vasectomized and non-vasectomized group, but statistically significant differences were found for GGT and LDH (p < 0.001).     

Analysis of spermatozoa from the proximal vas deferens of vasectomized men

As the health care system is oriented to provide service with finite dollars, nursing educators are being asked to demonstrate how continuing education for staff improves patient outcomes. The purpose of this study was to evaluate the impact of an orthopedic-geriatric continuing education program for nurses on the elderly patient who had sustained a hip fracture. A significant difference was found between the control and experimental unit patients with respect to time to first ambulation and length of stay on the orthopedic unit.     

Stereological estimation of Weibel-Palade bodies in the retinal vasculature of normal and diabetic dogs

The absolute volume of Weibel-Palade (WP) bodies, the storage organelles of von Willebrand factor (vWF), was estimated by a stereological method in a known volume of central retina from normal and 5-year diabetic dogs. The results showed that the volume of WP bodies present in the endothelium of the retinal vasculature varies with blood vessel type and in diabetes. In both diabetic and normal dogs the endothelium of the retinal veins contained a higher volume of WP bodies than that of the retinal arteries. In dogs which had been diabetic for a duration of 5 years the volume of WP bodies present in the endothelium of retinal veins was significantly greater than in the endothelium of veins from the control animals. However, there was no significant difference in the volume of WP bodies present in the endothelium of retinal arteries or capillaries between the two groups of animals.     

Clinical effects of longitudinal division of the corpus callosum in normal dogs

Longitudinal division of the corpus callosum was performed in six normal beagles to determine surgical morbidity. The corpus callosum was divided sagittally on the midline and the effect on neurological function was determined. Five of six dogs were clinically normal within 14 days or less after surgery. One dog had persistent but improving clinical signs consistent with a forebrain disturbance at 30 days after surgery. Overall, minimal morbidity and no mortality was associated with this surgical procedure. Further study is indicated to determine the efficacy of this surgical treatment for seizure control in dogs with idiopathic epilepsy.     

Dexamethasone pharmacokinetics in clinically normal dogs during low- and high-dose dexamethasone suppression testing

Dexamethasone pharmacokinetics was studied in 10 healthy dogs receiving high-dose administration of dexamethasone (dosage, 0.1 mg/kg of body weight, IV), alone or combined with ACTH (dosage, 0.5 U/kg, IV), or low-dose administration of dexamethasone (dosage, 0.01 mg/kg, IV) in an incomplete cross-over design. Serum samples were obtained at 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, 720, 1,080, 1,440, 1,920, 2,400, and 2,880 minutes after dexamethasone administration; dexamethasone was measured by radioimmunoassay validated for use in dogs. Dexamethasone pharmacokinetics was adequately described by a two-compartment first-order open model. Comparison of pharmacokinetics for the low- and high-dose protocols revealed dose dependence; area under the curve, mean residence time, clearance, and volume of distribution increased significantly when dexamethasone dosage increased. The elimination rate constant was significantly (P < 0.05) less, and the elimination half-life significantly greater for the high-dose protocols; however, the distribution rate constant and distribution half-life were not significantly different when high-dose protocols were compared with the low-dose protocol. Dose-dependent increases in volume of distribution and clearance may be related to saturation of protein-binding sites. Concurrent administration of ACTH did not affect dexamethasone disposition.