Lana Kaiser

Endothelium-Dependent Flow-Induced Dilation of Canine Femoral and Saphenous Arteries

We have characterized the dilation response to increased blood flow in the canine femoral and saphenous arteries. An arterio-venous shunt was created and changes in arterial diameter measured by sonomicrometer crystals. Increasing shunt flow approximately 10-fold caused a 9% increase in femoral and 15% increase in saphenous artery diameter. The dilation response consisted of a transient decrease in diameter, followed by a rapid dilation and a slow return to control when flow was decreased. The increased diameter was not a result of decreased transmural pressure or alterations in pulse pressure. After removing the endothelial cells, the vessels did not dilate to increased flow or topical acetylcholine (10(-5) M), but responses to norepinephrine (10(-5) M) and sodium nitroprusside (10(-4) M) were unaltered. Indomethacin, theophylline or propranolol did not affect the flow-induced dilation. Quinacrine, an inhibitor of phospholipase A2, attenuated the dilation response in a dose-dependent manner. We conclude that increased blood flow affects endothelial cells, causing an active dilation of arterial smooth muscle.

Aluminum-Induced Anemia

Although many questions still remain unanswered, it is clear that aluminum causes a microcytic hypoproliferative anemia and is one factor responsible for worsening anemia in patients with end-stage renal disease. Time course studies in a rat model have shown that the anemia is preceded by microcytosis; this has not yet been examined in man. The exact mechanism of aluminum-induced anemia is unknown, however it appears to involve inhibition of heme synthesis, either by inhibition of enzyme activity or interference with iron incorporation or utilization. The interrelationship between aluminum and iron, zinc, lead, or other metals in this anemia is also unknown, as are the effects of aluminum on erythroid colony forming units. The role of parathyroid hormone on aluminum-induced anemia has not been examined. Presently treatment of aluminum-induced anemia involves removal of the source of the aluminum, although recent studies with desferrioxamine show promise. It is unclear, however, exactly how desferrioxamine improves this anemia. It is clear, however, that aluminum in the dialysate can cause clinical problems including anemia, and that these problems can be substantially reduced if not eliminated by water treatment.

Can a week of therapeutic riding make a difference?—A pilot study

Abstract The objective of this research was to determine the effect of a five-day therapeutic riding day camp on childrens anger, quality of life and perceived self-competence. Our study sample involved 16 able-bodied individuals (11±4.4 years) with no known physical or psychological disability, and no known history of psychotropic medications. The Childrens Anger Inventory, Peds Quality of Life, and Self Perception Profile for Children were administered prior to riding on day one and after riding on day five. Results show that after five days of therapeutic riding camp, the total score of the anger inventory and scores for all sub-scales except frustration decreased significantly. No other differences were noted. Data analysis suggests that five days of therapeutic riding day camp can significantly impact on anger. These changes may be related to the childs relationship with the horse, the social environment of camp, the horse and riding, increased contact with nature, or a combination of these factors.

A dog and a "happy person" visit nursing home residents

Recent recognition of the importance of the human-animal bond has led to the proliferation of programs designed to improve the lives of nursing home residents through the use of animals. Because human-human interaction in the nursing home setting is often of an obligatory nature, we wondered if a visit from a nonjudgmental, outgoing, enthusiastic young adult (“a happy person”) could elicit the same positive influence as a visit from a nonjudgmental dog. The purpose of this study was to determine if elderly residents of a midwestern nursing home had a preference for the type of visitor (dog vs. person) when both visits were nonobligatory and nonjudgmental. Behaviors were evaluated to determine if one visitor was more likely to influence prosocial behaviors (moving closer, patting, smiling). Six residents were visited by both the dog and the happy person; 5 of 6 completed the final interview. Residents were equally likely to smile at and move closer to both visitors. Residents were more likelyto pat the dog. Three residents liked both visits equally; 1 preferred the dog, and 1 preferred the happy person. These data suggest that nonobligatoryvisits to nursing home residents from a happy person maybe as beneficial to the resident as visits from a dog.

Dirofilaria immitis: Do filarial cyclooxygenase products depress endothelium-dependent relaxation in the in vitro rat aorta?

Endothelial cells modulate the function of their underlying smooth muscle. Thus, altered endothelial behavior could be important in the pathogenesis of vascular and lymphatic diseases, including human and animal filariasis. Endothelium-dependent relaxation is depressed in both in vivo canine femoral artery of dogs infected with Dirofilaria immitis and in vitro rat aorta exposed to adult D. immitis. The experiments reported here were designed to determine if filarial cyclooxygenase products could depress endothelium-dependent relaxation in vitro. Pretreatment of the parasites, but not the vascular ring, with either indomethacin or aspirin, prevented filarial-induced depression of relaxation. Analysis of heartworm-conditioned medium by gas chromatography--mass spectrometry revealed two peaks in the biologically active medium that were not present in the control. One peak had a retention time and chromatographic profile characteristic of derivatized PGD2 standard, and the other was not identified. Incubation of the vascular ring with PGD2 mimicked filarial-induced depression of endothelium-dependent relaxation at low, but not high, concentrations of acetylcholine. Thus, filarial PGD2 may be involved in altered endothelium-dependent relaxation seen in heartworm-infected dogs.

Heritable bovine fetal abnormalities

The etiologies for congenital bovine fetal anomalies can be divided into heritable, toxic, nutritional, and infectious categories. Although uncommon in most herds, inherited congenital anomalies are probably present in all breeds of cattle and propagated as a result of specific trait selection that inadvertently results in propagation of the defect. In some herds, the occurrence of inherited anomalies has become frequent, and economically important. Anomalous traits can affect animals in a range of ways, some being lethal or requiring euthanasia on humane grounds, others altering structure, function, or performance of affected animals. Veterinary practitioners should be aware of the potential for inherited defects, and be prepared to investigate and report animals exhibiting abnormal characteristics. This review will discuss the morphologic characteristics, mode of inheritance, breeding lines affected, and the availability of genetic testing for selected heritable bovine fetal abnormalities.

Experimental model of type II bovine viral diarrhea virus- induced thrombocytopenia in neonatal calves

Thrombocytopenia has been associated with type II bovine viral diarrhea virus (BVDV) infection in immunocompetent cattle, but the mechanism is unknown. The purpose of the present study was to develop and characterize a model of type II BVDV-induced thrombocytopenia. Colostrum-deprived Holstein calves were obtained immediately after birth, given a BVDV-negative and BVDV antibody-negative plasma transfusion, housed in an isolation facility, and randomly assigned to either control (n = 4) or infected (n = 5) groups. Infected calves were inoculated by intranasal instillation on day 3 of age with 107 TCID50 of the prototype type II isolate, BVDV 890, whereas control calves were sham inoculated. Blood counts and virus isolations from serum, white blood cells, and platelets were performed daily until day 12 after infection, at which time all experimental calves were euthanatized, and pathologic, virologic, and immunohistochemical examinations were performed. On physical examination, the control calves remained normal, but the infected calves developed pyrexia and diarrhea characteristic of type II BVDV infection. The platelet count decreased in all infected calves, and a statistically significant difference in the platelet count between control and infected calves was observed on days 7–12 after infection. In addition, the mean platelet volume and white blood cell counts also decreased. Examination of the bone marrow from the infected calves revealed immunohistochemical staining for BVDV antigen in megakaryocytes and evidence of concurrent megakaryocyte necrosis and hyperplasia.

Companion Animals and Adaptation in Chronically Ill Children

Almost 20 million children in the U.S. have a chronic illness. Chronic illness requires ongoing management in the home, often with complex, stressful regimens. The increased lifespan of chronically ill children may lead to increased long term psychosocial and physical sequelae. Enhancing the quality of life for these children could promote optimal long-term adaptation. Health benefits of companion animals have been described across psychosocial, physiological, and behavioral spheres for healthy children and children with disabilities. These benefits have not been empirically examined for chronically ill children. This paper uses a stress-coping model to examine the role animals may play in adaptation for children with chronic illnesses. The contribution of companion animals to the constructs within the model and the adaptation process is discussed. This model provides a potential theoretical framework for synthesizing literature and pursuing empirical work on the role of companion animals in chronic childhood illness.

Development of a sensitive immunoradiometric assay for detection of platelet surface-associated immunoglobulins in thrombocytopenic dogs

OBJECTIVE To develop a direct assay to measure platelet surface-associated immunoglobulins (PSAIg) in dogs and to determine whether the assay is useful in the diagnosis of immune-mediated thrombocytopenia (IMT). ANIMALS 20 healthy dogs were used to develop reference intervals, and 23 dogs with IMT and 17 with non-IMT were used to evaluate the clinical use of this assay. PROCEDURE After optimization of platelet collection and assay conditions, concentrations of PSAIg were measured, using radiolabeled staphylococcal protein A (SpA) and polyclonal antibodies against canine IgG (anti-gamma) and IgM (anti-micro). Concentrations of PSAIg were expressed as the percentage of radiolabeled immunoglobulin detector bound. RESULTS Cut-off values (mean + 3 SD) were as follows: SpA, 1.1%; anti-gamma, 1.3%; and anti-micro, 3.5%. Values greater than these cut-off values were considered positive. Values determined by use of radiolabeled SpA for all dogs with IMT were greater than the cut-off value; values were considered high positives (> 5 times cut-off value) for 22 of these 23 dogs. Although 9 of 17 dogs with non-IMT also had PSAIg concentrations greater than the cut-off value, values were considered high positives for only 3 of these 9 dogs. CONCLUSIONS AND CLINICAL RELEVANCE The immunoradiometric assay developed is a reliable and sensitive method to detect PSAIg in dogs. However, to obtain accurate results, optimum temperature, time, and storage conditions must be used. Detection of increased concentrations of PSAIg in dogs presumed to have non-IMT should alert clinicians to reconsider an immune-mediated basis for the thrombocytopenia.

Cyclooxygenase inhibitors depress norepinephrine constriction of rat abdominal, but not thoracic, aorta

Experiments were done on aortic rings (thoracic and abdominal) from young and retired breeder Lewis and Sprague-Dawley male rats. Constriction responses to norepinephrine, 5-hydroxytryptamine (5-HT), and prostaglandin F2 alpha, were done +/- the cyclooxygenase blockers, indomethacin or mefenamic acid. Indomethacin significantly depressed norepinephrine constriction in abdominal (but not thoracic) aorta of all groups. In additional studies of abdominal aorta from Lewis retired breeders, indomethacin and mefenamic acid depressed norepinephrine (but not 5-HT or prostaglandin F2 alpha) construction. Furthermore, indomethacin depressed norepinephrine constriction in vessels denuded of endothelial cells. The thromboxane receptor antagonist SQ 29548 did not alter norepinephrine constriction. Thus, in rat abdominal aorta, norepinephrine constriction is mediated by a constrictor prostanoid of vascular smooth muscle origin that is not thromboxane A2.