Search PubMed⌕ Search

Biomedical subjects

R R Hanson

Publications and source records attributed to R R Hanson.

At least 19 recordsLinked to original sources
PubMed2001

Effects of intravenous lidocaine overdose on cardiac electrical activity and blood pressure in the horse.

This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to administration of lidocaine, blood samples for lidocaine analysis, heart rate, mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, respiratory rate and electrocardiographic (ECG) data were collected. After recording baseline data, repeat data were collected at 5 min intervals until signs of intoxication were observed. The range of serum lidocaine concentrations at which the clinical signs of intoxication were observed was 1.85-4.53 microg/ml (mean +/- s.d. 3.24 +/- 0.74 microg/ml). Statistically significant changes in P wave duration, P-R interval, R-R interval and Q-T interval were observed in comparison to control values, as a result of lidocaine administration. These changes in ECG values did not fall outside published normal values and were not clinically significant. Heart rate, blood pressures and respiratory rates were unchanged from control values. This study establishes toxic serum lidocaine levels in the horse, and demonstrates that there were no clinically significant cardiovascular effects with serum lidocaine concentrations less than those required to produce signs of toxicity.

Anesthetics, Local↗
PubMed2000

Pseudallescheria boydii infection of the nasal cavity of a horse.

An 18-year-old 454-kg (1,000-lb) American Quarter Horse gelding was evaluated because of chronic intermittent malodorous right-sided nasal discharge. Endoscopy revealed a mycotic plaque in the nasal cavity adjacent to the nasomaxillary opening of the right caudal maxillary sinus. The nasomaxillary opening appeared to be larger than normal. Fungal culture of specimens of the mycotic plaque yielded Pseudallescheria boydii. The horse was treated with 2% miconazole intranasally, sodium iodide i.v., and potassium iodide p.o. Thirty and 60 days after treatment was initiated, the nasal cavity was found to be free of infection.

Animals↗
PubMed2000

Ligature slippage during standing laparoscopic ovariectomy in a mare.

Suture ligature failure is a potential complication during laparoscopic ovariectomy techniques utilizing ligatures as a means of hemostasis. This complication in the standing mare and the successful use of laparoscopic electrosurgical instrumentation as the sole means of providing hemostasis to the mesovarium of a mare are described.

Animals↗
PubMed1997

Ovariectomy of granulosa cell tumors in mares by use of the diagonal paramedian approach: 12 cases (1989-1995).

OBJECTIVE: To describe the short- and long-term survival rates in horses undergoing ovariectomy for granulosa cell tumors by use of the diagonal paramedian approach. DESIGN: Retrospective case study. ANIMALS: 12 horses with granulosa cell tumors. PROCEDURE: A diagonal paramedian approach for unilateral ovariectomy was used for removal of each mare's granulosa cell tumor. Information about complications and outcomes was analyzed. RESULTS: Only minimal complications were detected postoperatively when the diagonal paramedian approach was used, regardless of the preferred technique for ovarian pedicle ligation or incisional closure and the use of pre- and postoperative medications. Clinical signs of moderate or severe postoperative abdominal pain were not evident in any of the 12 horses. Short- and long-term survival rates were 100%. CLINICAL IMPLICATIONS: The diagonal paramedian approach was advantageous for ovarian tumor removal, because the ovary was immediately adjacent to the body wall at a portion of the incision site. Size of the ovary was not a limitation, because muscle tissues at the edges of the incision were flexible and easily retractable. All of these factors improved exposure, decreased traction on the ovary, increased our ability to observe the vasculature, and decreased postoperative morbidity, aiding in the removal of granulosa cell tumors in mares.

Animals↗
PubMed1996

Medical treatment of horses with ileal impactions: 10 cases (1990-1994).

OBJECTIVE: To evaluate clinical and laboratory findings for horses treated medically for ileal impactions. DESIGN: Retrospective case series. ANIMALS: 10 horses with primary ileal impaction that were treated successfully with medical treatment alone. PROCEDURE: Medical records were reviewed for all horses with naturally developing ileal impaction seen at our hospital between 1990 and 1994. RESULTS: Transrectal palpation revealed an impaction in the midabdominal area in all horses. Generalized distention of the small intestine was evident in 6 horses, whereas 4 horses were examined early in the course of the condition and did not have intestinal distention. Treatment consisted of intravenous administration of a balanced electrolyte solution, nasogastric intubation and siphonage, and administration of analgesics. Mineral oil was administered after gastric reflux had ceased. Mean time for resolution of ileal impaction was 11.7 hours. CLINICAL IMPLICATIONS: Medical treatment may be a viable alternative for horses that cannot have surgery, provided persistent signs of severe pain or progressive gaseous distention of the small intestine are not features of the condition. Improvement of cardiovascular status, reduction in signs of abdominal pain, decrease in distention of loops of small intestine during repeated transrectal examination, softening of the impaction, and decreases in amounts of gastric reflux were indicative of a response to medical treatment.

Animals↗
PubMed1996

Immunohistochemical analysis of an equine model of synovitis-induced arthritis.

OBJECTIVES: To use lipopolysaccharide (LPS) to create synovitis in the midcarpal joint of ponies, and to assess the morphologic, histochemical, and immunohistochemical effects of synovitis on articular cartilage of the third carpal bone. ANIMALS: 2- to 3-year-old ponies, 6 control (group 1) and 6 treated (group 2). PROCEDURE: Synovitis was induced in 1 midcarpal joint of group-2 ponies by intra-articular injections of LPS (0.02 micrograms/kg of body weight), morphine (0.1 mg/kg), and saline solution (group 2a) and a morphine and saline solution alone in the contralateral midcarpal joint (group 2b). Articular cartilage sections and attached synovial membrane from the third carpal bones were examined by immunohistochemical distribution of interleukin 1 beta, tumor necrosis factor (TNF)-alpha, TNF receptors (P55, P75) and 3-B-3(-) epitopes, and by localization of proteoglycans (metachromatic staining). Proteoglycan extracts were assessed by metachromatic staining or western blotting and immunohistochemical staining, using anti-3-B- antibodies. RESULTS: Enhanced immunoreactivity for the cytokines and receptors was found in inflamed synovial membrane and noncalcified cartilage (group 2a more than 2b). Metachromasia of the noncalcified cartilage was greater in group-1 than in group-2a and group-2b specimens. In group 2a, chondrocyte hypertrophy and enhanced immunoreactivity for 3-B-3(-) epitope in areas of increased cytokine immunoreactivity suggested possible phenotypic change of the chondrocytes in response to synovitis. Immunohistochemical analysis by western blotting of proteoglycan extracts indicated strong 3-B-3(-) epitope immunolocalization in group-2a, weaker staining in group-2b, and barely detectable stain in group-1 specimens, which correlated with in situ immunolocalization. CONCLUSIONS: Intra-articular administration of LPS may be used to induce a synovial environment conductive to increased immunoreactivity of interleukin 1 beta, TNF-alpha, and its receptors in equine synovial membrane and articular cartilage. These cytokines may be involved in the early phenotypic change of chondrocytes that is believed to occur in osteoarthritis and is characterized in this study by enhanced 3-B-3(-) epitope immunoreactivity and chondrocyte hypertrophy.

Animals↗
PubMed1996

Immunolocalization of stromelysin, tumor necrosis factor (TNF) alpha, and TNF receptors in atrophied canine articular cartilage treated with hyaluronic acid and transforming growth factor beta.

OBJECTIVE: To evaluate the ability of hyaluronic acid (HA), with and without transforming growth factor beta (1GF-beta), to stabilize the catabolic processes associated with atrophy of articular cartilage. ANIMALS: 20 adult, skeletally normal, hound-type dogs. PROCEDURE: Dogs (20 to 30 kg) were randomly assigned to 1 of 5 groups. One group served as untreated controls. Bivalve casts were placed on the left hind limbs of the remaining 16 dogs to limit weightbearing and motion of the limb for 92 days. One group served as the cast control. Beginning on day 56, 3 groups received aseptic intra-articular injections in the left stifles of either 5 mg of HA or 5 mg of HA containing either 20 or 50 micrograms of TGF-beta. Intraarticular injections were repeated at 4-day intervals until the end of the study. Or day 92, stifles were harvested at necroscropy. Medial femoral condyle were histologically processed, and the articular cartilage was stained for the presence of proteoglycans, stromelysin, tumor necrosis facto (TNF) alpha, and TNF receptors (p55 and p75). RESULTS: Decreased metachromasia was evident in the cartilage matrix of all cast groups, with the smallest decrease in the HA-treated group. Stromelysin was immunolocalized in articular cartilage of the cast (left) limbs of cast control and both HA/TGF-beta-treated groups. TNF-alpha was localized in articular cartilage of all cast (left) and right limbs, except those of the HA-treated group. Receptors for TNF were observed in both limbs of untreated control and cast control groups and cast limbs of HA/TGF-3-treated groups. The receptors were not localized in the right limbs of the HA with or without TGF-beta-treated groups. TGF-beta did not decrease stromelysin or TNF-alpha or receptors at the doses used. CONCLUSIONS: HA may mediate a chondrostabilizing influence on articular cartilage by down-regulating TNF-alpha importantly. HA appeared to exert its inhibitory influence on TNF-alpha, as well as stromelysin and TNF receptors, on a systemic basis. CLINICAL RELEVANCE: Results provide insight into the mode of action of HA as a therapeutic agent for arthritis and its stabilizing influence on cartilage metabolism.

Animals↗
PubMed1994

Specificity of bronchoalveolar lavage for the diagnosis of fat embolism syndrome.

The diagnosis of fat embolism syndrome (FES) is relatively difficult because simple, quantitative criteria have been lacking. The results of a recent study, however, suggest that the diagnosis of FES can be made if more than 5 per cent of the cells in fluid obtained by bronchoalveolar lavage are lipid-laden. Our study was designed to assess the specificity of this lipid staining test of bronchoalveolar cells for diagnosing FES in a series of patients coming to the pulmonology clinic. Thirty-four consecutive patients with suspected pulmonary diseases, but not FES, underwent routine bronchoscopy. Bronchoalveolar fluid was applied to slides, fixed with formalin, and stained with oil red 0. Three hundred consecutive cells of each specimen were observed for red-staining droplets. More than 5 per cent of bronchoalveolar lavage cells stained for lipids in 25 of the 34 subjects. The calculated specificity, assuming a negative finding is defined as < or = 5 per cent lipid-laden cells in the sample, was 26.5 per cent. We conclude that staining of bronchoalveolar lavage cells for lipids is not a specific test for FES.

Bronchoalveolar Lavage Fluid↗
PubMed1992

Evaluation of peritoneal fluid following intestinal resection and anastomosis in horses.

Postoperative abdominal fluid changes were compared in 2 groups of horses; those undergoing double small-colon resection and anastomosis (n = 10) and those undergoing exploratory celiotomy alone (n = 5). Peritoneal fluid was collected before surgery and on postoperative days 1, 3, 5, and 7. Total and differential nucleated cell counts, RBC numbers, and total protein and fibrinogen concentrations were evaluated. In both groups, all values were significantly higher than normal on the first postoperative day (after small-colon resection and anastomoses, WBC = 130,350 +/- 23,310 cells/microliters, RBC = 7,389,000 +/- 6,234,000 cells/microliters, total protein = 3.63 +/- 0.16 g/dl; after exploratory celiotomy alone, WBC = 166,620 +/- 34,340 cells/microliters, RBC = 295,000 +/- 86,070 cells/microliters, total protein 4.38 +/- 0.54 g/dl). The number of total peritoneal nucleated cells and RBC significantly decreased after the first postoperative day, whereas total protein and fibrinogen concentrations, percent neutrophils, and percent mononuclear cells remained unchanged. None of the values had returned to normal by postoperative day 7 (after small-colon resection and anastomoses, WBC = 45,600 +/- 8,765 cells/microliters, RBC = 95,390 +/- 53,380 cells/microliters, total protein = 4.39 +/- 0.23 g/dl; after exploratory celiotomy alone, WBC = 43,340 +/- 7,746 cells/microliters, RBC = 12,860 +/- 11,790 cells/microliters, total protein = 3.92 +/- 2.20 g/dl.) The resection and anastomosis group had a significantly lower total protein concentration on the first postoperative day and a significantly higher mean total RBC count over the entire 7-day postoperative evaluation than did horses that underwent celiotomy alone. Other values in the 2 groups of horses did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1988

Headaches in childhood.

Childhood headache is a common problem. The approach to evaluation and therapy is similar to that in adults with the exception that the differential is slightly altered and varies by age. Methods of evaluation have been proposed based on the time course of the illness as well as on pathophysiologic considerations. Although serious intracranial disease needs to be ruled out, in most cases chronic recurrent headache of childhood represents migraine. When doubt exists, close follow-up for 4 to 6 months should clarify the issue. Migraine variants are described that are uncommon or not seen in adults, and their differential diagnosis is discussed. The most difficult differential is between that of migraine and seizures. Variations in history and associated findings are described to help in the diagnosis of seizure versus migraine. Finally, methods of treatment are given based on my experience and review of the current literature. Many patients with migraine will improve over time regardless of what is done, and this should be kept in mind when treating these patients.

Child↗
PubMed1988

Comparison of staple and suture techniques for end-to-end anastomosis of the small colon in horses.

Two techniques for end-to-end anastomosis of the small colon were evaluated in each of 6 horses. A simple interrupted suture pattern that excluded the mucosa and was oversewn with an inverting suture was compared with a triangulated double-row pattern of stainless steel staples. Anastomotic sites were evaluated at 2 weeks, 2 months, and 6 months for extent of abdominal adhesions, lumen diameter at anastomotic sites, bursting pressures, and healing response. Clinical postoperative complications were not associated with either technique. At postmortem examination, there was extensive adhesion formation from the mesocolon to the stapled anastomotic site. The suture technique resulted in greater luminal diameters (P less than or equal to 0.05), with good apposition of the tissue layers. Staples were missing as early as 2 weeks after surgery, and their loss was associated with separation of the muscularis at later evaluation periods. Regardless of technique, all but one anastomotic segment burst away from the anastomotic site along the mesenteric taenial band. For the 12 anastomoses performed in normal horses, the suturing technique was better than the stapling technique because of significantly larger lumen diameters, better anastomotic healing, and minimal intra-abdominal adhesion formation.

Anastomosis, Surgical↗
PubMed1988

Evaluation of three techniques for end-to end anastomosis of the small colon in horses.

In an attempt to determine the best method for surgical removal of devitalized small colon lesions, 12 horses underwent a double small colon resection and end-to-end anastomosis. In 4 horses (study 1), an appositional single-layer (APP-1) suture pattern was compared with an inverting 2-layer (INV-2) suture pattern. In 8 horses (study 2), an appositional 2-layer (APP-2) suture pattern was compared with the INV-2 suture technique. Polydioxanone suture (size 1-0), was used. Horses were evaluated at necropsy 3, 10, 14, 28, or 56 days after surgery. Postoperative complications (peritonitis, impaction, or excessive adhesions) were encountered in 100, 42, and 13% of the APP-1, INV-2, and APP-2 anastomoses, respectively. Postmortem evaluation of the small colon revealed dehiscence of the anastomotic site, diffuse peritonitis, and adhesion formation in 3 of the 4 horses in which the resection line was closed with the APP-1 pattern. With the INV-2 and APP-2 techniques, more intestinal inversion was present in the nontaenial than in the taenial portion of the small colon. More postoperative impactions were found with the INV-2 (n = 5) anastomoses than with the APP-2 (n = 1) technique; this appeared to be the result of excessive tissue inversion. There was no difference in lumen diameter between the INV-2 and the APP-2 techniques (P greater than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗