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Biomedical subjects

P N Olson

Publications and source records attributed to P N Olson.

At least 19 recordsLinked to original sources
PubMed1992

Clinical and laboratory findings associated with actual or suspected azoospermia in dogs: 18 cases (1979-1990).

Eighteen dogs were evaluated for azoospermia, 8 of which had sired pups. On the basis of history, physical examination, and various laboratory evaluations, the cause and site of azoospermia varied. Two dogs that had never sired pups had likely been azoospermic from puberty (congenital azoospermia). Two dogs were azoospermic as a result of tumors (Sertoli cell tumor and malignant astrocytoma of the pituitary gland). Deposits of IgG were observed in testicular biopsy samples, which suggested an auto-immune cause for azoospermia in 5 dogs. One of the 5 dogs with IgG deposits in testicular tissues also had evidence of immune-mediated thyroiditis. Culturing of microbes in the semen was not helpful in determining potential causes of azoospermia, and results did not correlate with organisms isolated from testicular biopsy samples or with the finding of inflammation in biopsy samples. Because 6 dogs had relatives with histories of reproductive dysfunction, inbreeding also must be considered when evaluating dogs for azoospermia.

Alkaline Phosphatase↗
PubMed1992

Shifting pneumothorax after heart-lung transplantation.

Heart-lung transplantation involves the total replacement of two of the most complex organs of the thoracic cavity. This procedure is usually reserved for patients with failure of both systems, such as in primary pulmonary hypertension or chronic Eisenmenger physiology. The en bloc replacement of the heart and lungs leaves an open communication between the two sides of the thorax that may allow air or fluid to shift from one side to the other. To evaluate this possibility, the authors reviewed the chest radiographs of 25 heart-lung transplant recipients for signs of rapidly changing pneumothoraces that could not be explained by the conventional dynamics of pleural physiology. A series of postoperative radiographs showed unusual shifting or apparently rapid disappearance of pneumothoraces in eight patients. Decompression of a pneumothorax with a contralateral chest tube was a phenomenon observed in six of these patients.

Adolescent↗
PubMed1992

Concentrations of luteinizing hormone and follicle-stimulating hormone in the serum of sexually intact and neutered dogs.

Concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured in serum samples obtained from 100 dogs. Groups (n = 25/group) consisted of sexually intact and ovariohysterectomized bitches and sexually intact and castrated male dogs. Mean (+/- SD) concentrations of LH in the serum of sexually intact and ovariohysterectomized bitches were 1.2 (+/- 0.9) and 28.7 (+/- 25.8) ng/ml, respectively. Mean concentrations of FSH in the serum of sexually intact and ovariohysterectomized bitches were 98 (+/- 49) and 1,219 (+/- 763) ng/ml, respectively. Mean concentrations of LH in the serum of sexually intact and castrated male dogs were 6.0 (+/- 5.2) and 17.1 (+/- 9.9) ng/ml, respectively. Mean concentrations of FSH in the serum of sexually intact and castrated male dogs were 89 (+/- 28) and 858 (+/- 674) ng/ml, respectively. In addition to history, physical examination results, and other laboratory values, the measurement of serum gonadotropin concentrations may aid in determining whether dogs have been neutered.

Animals↗
PubMed1991

Case report 703: Multifocal osteosarcoma.

There are two theories concerning the origin of multifocal osteogenic sarcoma: In one, the lesions all arise synchronously as multiple, simultaneously appearing, primary tumors, and in the other, there appears to be one dominant site with early and rapidly progressive metastatic disease. We believe that our patient fits into the second group with a primary right (distal-end) femoral osteogenic sarcoma with early and rapid metastasis. Bone scan, chest CT, and MRI examinations played an essential role in the initial evaluation and follow-up of this patient with osteosarcomatosis. The multiple modalities also offered a greater sensitivity in the detection and for the surveillance of the progression of the condition.

Bone Neoplasms↗
PubMed1991

Clinical approach for evaluating dogs with azoospermia or aspermia.

There are various causes for azoospermia and aspermia in dogs. Unfortunately, even when the site and cause of infertility are determined, reversing the disorder may be difficult. As new information are gathered on the maturation of canine spermatozoa, testicular immunity, microsurgical techniques for anastomosing occluded ducts, and the physiologic control of testicular and ejaculatory function, however, new therapies might be developed to prevent or reverse azoospermia and aspermia.

Animals↗
PubMed1991

Use of adult dog serum as a substitute for colostrum in the neonatal dog.

Failure to obtain passive transfer of immunity via colostrum can be detrimental to the health and survival of a young pup. It has been stated that pups that do not receive colostrum in the first 2 days after birth, be given adult dog serum as a source of protective immunoglobulins. Twenty-five Beagle pups were obtained by cesarean section from 6 Beagle bitches. The pups were allotted to 3 groups at birth. Group 1 was a control group and was allowed to suckle colostrum. Group-2 pups received 22 ml of pooled adult dog serum/kg of body weight (10 ml/lb) SC at birth. Group-3 pups were given 22 ml of pooled adult dog serum/kg by stomach tube at birth. Pups from groups 2 and 3 were separated from the bitch for 48 hours to prevent colostral antibody absorption and were fed a commercially available milk replacer by stomach tube. After 48 hours, all pups were returned to the bitch until they were weaned at 6 weeks of age. Blood samples were collected from all of the pups at birth and on days 1, 2, 7, 14, 21, 28, and 35. The concentration of IgA, IgG, and IgM in serum was determined by radial immunodiffusion and compared by use of a one-way analysis of variance. The control pups had significantly higher serum concentrations of IgA and IgG, than the pups in groups 2 and 3 on days 1 and 2 and 2 and 7, respectively. Group-2 pups had significantly higher serum IgM concentrations on day 1 than either group 1- or group-3 pups.

Animals↗
PubMed1989

Female pseudohermaphroditism in three sibling greyhounds.

Three 18-month-old Greyhound siblings were found to have female pseudohermaphroditism. The disorder in sexual differentiation likely developed because the dam received testosterone proprionate for estrus prevention. All 3 siblings had a prepuce (no penis), vagina, uterus, and ovaries.

Abnormalities, Drug-Induced↗
PubMed1988

Perianal adenomas and hypertestosteronemia in a spayed bitch with pituitary-dependent hyperadrenocorticism.

Hypertestosteronemia was diagnosed in a spayed bitch with pituitary-dependent hyperadrenocorticism and perianal adenomas. Serum concentrations of cortisol and testosterone decreased after treatment with mitotane was instituted. Excessive testosterone in this dog was thought to have been produced by the adrenal cortex, possibly in response to excessive ACTH concentrations. Development of androgen- or estrogen-responsive tumors in castrated dogs may be an early indication of adrenocortical hyperfunction.

Adenoma↗
PubMed1988

Serum concentrations of thyroxine and 3,5,3'-triiodothyronine in dogs before and after administration of freshly reconstituted or previously frozen thyrotropin-releasing hormone.

Concentrations of serum thyroxine (T4) and 3,5,3'-triiodothyronine (T3) were determined after the administration of freshly reconstituted thyrotropin-releasing hormone (TRH), reconstituted TRH that had been previously frozen, or thyrotropin (TSH) to 10 mature dogs (6 Greyhounds and 4 mixed-breed dogs). Thyrotropin-releasing hormone (0.1 mg/kg) or TSH (5 U/dog) was administered IV; venous blood samples were collected before and 6 hours after administration of TRH or TSH. Concentrations of the T4 and T3 were similar (P greater than 0.05) in serum after administration of freshly reconstituted or previously frozen TRH, indicating that TRH can be frozen at -20 C for at least 1 week without a loss in potency. Concentrations of T4, but not T3, were higher after the administration of TSH than they were after the administration of TRH (P less than 0.01). Concentrations of T4 increased at least 3-fold in all 10 dogs given TSH, whereas a 3-fold increase occurred in 7 of 10 dogs given freshly reconstituted or previously frozen TRH. Concentrations of T4 did not double in 1 dog given freshly reconstituted TRH and in 1 dog given previously frozen TRH. Concentrations of T3 doubled in 5 of 10, 2 of 10, and 5 of 10 dogs given TSH, freshly reconstituted TRH, or previously frozen TRH, respectively. Results suggested that concentrations of serum T4 are higher 6 hours after the administration of TSH than after administration of TRH, using dosage regimens of 5 U of TSH/dog or 0.1 mg of TRH/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Efficacy and toxicity of tamoxifen citrate for prevention and termination of pregnancy in bitches.

Five groups of bitches were given tamoxifen citrate (1 mg/kg of body weight) orally twice daily for 10 days. Drug administration commenced during late proestrus, day 4 of estrus, day 2 of diestrus, day 15 of diestrus, or day 30 of diestrus (n = 4/group). Nineteen of the bitches accepted natural mating by 1 or more of 3 stud dogs of known fertility (1 bitch did not). Twenty days after cessation of drug administration, ovarian, uterine, and hepatic specimens were obtained from each bitch in 4 of the groups. Pregnancy proceeded to natural termination in bitches of the remaining group (diestrous day 30). Pregnancy was not detected in any bitch of the proestrus, estrous, or early diestrous groups. Of 4 bitches of each of the remaining groups (diestrous day 15 and diestrous day 30), 2 aborted fetuses and/or resorbed placental remnants; the other 2 bitches in each of these groups had normal-appearing fetuses (diestrous day-15 group) or clinically normal pups (diestrous day-30 group). Of the 20 bitches given tamoxifen citrate, 5 developed endometritis with or without pyometra, and 4 of these had ovarian cysts. Although tamoxifen citrate is effective for preventing or terminating pregnancy in the bitch, the regimen used in the study reported here was associated with high frequency of pathologic changes in the reproductive tract.

Abortion, Induced↗
PubMed1987

Luteal function in the bitch: changes during diestrus in pituitary concentration of and the number of luteal receptors for luteinizing hormone and prolactin.

The concentration of unoccupied luteal receptors for luteinizing hormone (LH) and prolactin, and the concentration of these two hormones in the pituitary was determined in 11 groups of bitches (n = 3 or 4/group) representing stages from proestrus through Day 80 of diestrus. Despite dramatic changes in serum concentrations of progesterone, the concentration of luteal receptors for LH and prolactin was quite constant throughout the entire luteal phase. In association with the ovulatory surge of LH, pituitary concentration of LH decreased abruptly from proestrus to Day 2 of diestrus, and was then gradually replenished during the remainder of diestrus. The concentration of prolactin in the pituitary did not vary significantly from proestrus through late diestrus.

Animals↗
PubMed1987

Concentrations of carnitine in the seminal fluid of normospermic, vasectomized, and castrated dogs.

Concentrations of total carnitine (free and esterified) were determined in seminal fluids from 12 normospermic dogs before treatment and from the same 12 dogs after assignment to control, vasectomized, or castrated treatment groups (4 dogs each). Before treatment, the mean concentration (+/- SD) of carnitine in seminal fluid was 946 +/- 345 nmol/ml and was not significantly different (P greater than 0.05) among groups on any seminal collection day. After surgery, mean concentrations of carnitine in seminal fluid from vasectomized and castrated dogs were 49 +/- 9 and 14 +/- 5 nmol/ml, respectively and were lower (P less than 0.001) than the mean concentration in control (sexually intact) dogs. Dogs with obstructive azoospermia may be distinguished from those with aspermatogenesis (secretory azoospermia) by measuring seminal carnitine concentration. Seemingly, the epididymis is the major source of carnitine in canine seminal fluid, because the concentration of carnitine in prostatic fluid was only 58 +/- 53 nmol/ml, whereas the concentration of carnitine in 6 pools of epididymal fluid was 18.8 +/- 3.9 mumol/ml.

Animals↗