Magnetoelectronics

An approach to electronics is emerging that is based on the up or down spin of the carriers rather than on electrons or holes as in traditional semiconductor electronics. The physical basis for the observed effects is presented, and the initial successful applications of this technology for information storage are reviewed. Additional opportunities for the exploitation of this technology, which are currently under study, are described.     

Influence of nitrogen,photoperiod, cutting type,and clone on root and shoot development of rooted stem cuttings of sweetgum

This study was designed to test the effects of nitrogen fertilization, photoperiod, cutting type, and clone on root and shoot development of stem cuttings of sweetgum (Liquidambar styraciflua). Differences in the growth of roots and shoots were observed as a result of weekly applications of varying levels of nitrogen (N) fertilization (0, 25, 50, 100, or 200 mg N/liter). As the concentration of N increased, new-shoot dry weight increased, but root dry weight decreased at rates greater than 50 mg N/liter. The percentage of rooted cuttings surviving also decreased as N concentrations increased past 50 mg N/liter. A night-interruption light treatment did not significantly affect survival percentages or the amount of root and shoot growth. Across all treatments, only 46% of all cuttings produced new-shoot growth within a 15-week period following rooting. Cutting type (terminal or sub-terminal) affected rooted cutting development. A higher percentage of terminal cuttings survived and were deemed plantable. In contrast, sub-terminal cuttings produced more shoot and root growth. Differences among clones were observed for all traits measured.Manipulating N fertilization, in conjunction with using clones that propagate well, has the potential of producing rooted cuttings of a size adequate for plantation establishment. However, higher percentages of cuttings that produce new shoot growth shortly after rooting must be achieved.     

Agonist-induced adherence of equine neutrophils to fibronectin- and serum-coated plastic is CD18 dependent.

Adherence to vascular endothelium and extracellular matrix proteins is a pre-requisite for neutrophil accumulation at sites of inflammation. In this study, equine neutrophil adherence to fibronectin and autologous serum-coated plastic in response to PAF, hrIL-8, hrC5a and PMA has been measured. In addition, the mechanisms involved have been investigated using monoclonal antibodies (MoAbs) against the beta2 integrin CD18. PAF and hrC5a caused similar, concentration dependent, increases in adherence to fibronectin- and serum-coated plastic (maximum responses 19 +/- 4% and 19 +/- 3% for PAF and 15 +/- 4% and 16 +/- 2% for hrC5a on fibronectin- and serum-coated plastic, respectively). Adherence in response to PMA, although not reaching a maximum over the time course studied, was of a similar magnitude on the two surfaces (41 +/- 1% and 38 +/- 2% with 10(-7) M PMA on fibronectin- and serum-coated plastic, respectively). In contrast, the maximum adherence caused by hrIL-8 was significantly lower on fibronectin- than on serum-coated plastic (9 +/- 3% vs. 17 +/- 2%; 10(8) x M hrIL-8). Pre-incubation with MoAbs against CD18 (H20A and 6.5E) caused concentration related inhibition of stimulus-induced adherence to both fibronectin- and serum-coated plastic. Equine neutrophil adherence in response to PAF, hrIL-8, hrC5a and PMA therefore appears to be mediated by a CD18 dependent mechanism.     

Heat Shock Protein 70 and Sex Steroid Receptors in the Follicular Structures of Induced Ovarian Cysts

The purpose of this study was to estimate the expression and relative amounts of estrogen (ER) and progesterone receptors (PR) and their isoforms as well as heat shock protein 70 (HSP70) in ovaries of rats with induced cystic ovarian disease (COD). Primary, secondary, tertiary, atretic and cystic follicles were evaluated by immunohistochemistry and total ovarian proteins were analyzed by Western blot. In the granulosa layer, growing and cystic follicles in the treated group have a higher expression of ERα than growing follicles of control individuals. In the theca interna layer, tertiary follicles presented a significantly higher expression of ERα in the treated group. An increase in total ERα protein was detected in the treated group. Granulosa cells of all growing, atretic and cystic follicles show a lower expression of ERβ in animals with COD, and the total protein expression of ERβ was lower in this group. The expression of PR was lower in the granulosa cell layer of tertiary and cystic follicles in treated animals, and theca interna layer had less intense immunostaining in this group. Although there were no differences in the expression of PR-B by Western blotting, the expression of PR-A was higher and the expression of PR-C was smaller in the treated group. An intense HSP70 immunostaining was observed in the cells of cystic follicles. By Western blotting, higher protein expression of HSP70 was detected in the ovarian samples of the control group than those of the treated ones. Ovaries of animals with COD exhibited an altered steroid receptor expression and subtype balance as compared with control animals, and an increase in HSP70 immunoexpression.     

Comparison of two methods of detecting purulent vaginal discharge in postpartum dairy cows and effect of intrauterine cephapirin on reproductive performance

Objective   Part 1: compare the use of a Metricheck™ device (a stainless steel probe with a semi-spherical rubber cup attached at one end) to sample the contents of the anterior vagina with a vaginal speculum examination for the diagnosis of pus in the vagina of postpartum dairy cows and to investigate the association of that pus with reproductive performance. Part 2: assess the effect of a single intrauterine infusion of 500 mg cephapirin in cows diagnosed with vaginal purulent or mucopurulent discharge 7 to 28 days after calving on reproductive performance.
Procedure   Six herds were visited fortnightly to examine cows that had calved between 7 and 28 days (n = 423) with both the Metricheck device and a vaginal speculum to score, by each method, the vaginal discharge from 0 (clear or absent) to 3 (purulent) for each animal included in the study. Half of the cows that had a positive discharge score (1 to 3 by either examination method) were then treated with an intrauterine infusion of 500 mg of cephapirin. The relationship between Metricheck score, vaginoscopy score, treatment and reproductive performance was assessed.
Results   There was a substantial measure of agreement between each method when scores were analysed by status. Cows that were positive with either method had inferior reproductive performance compared with cows with a score of zero. Treatment of cows diagnosed with a purulent or mucopurulent discharge with intrauterine cephapirin improved reproductive performance in both the vaginoscopy and Metricheck groups.     

Neutrophil and platelet activation in equine recurrent airway obstruction is associated with increased neutrophil CD13 expression, but not platelet CD41/61 and CD62P or neutrophil–platelet aggregate formation

Recurrent airway obstruction (RAO) in mature horses is characterized by reversible airway obstruction and neutrophilic inflammation; there is also functional activation of circulating platelets and neutrophils. This study was undertaken to determine if changes in activation marker expression and heterotypic aggregate formation can be used as an indicator of this increased functional responsiveness.In vitro conditions for flow cytometric measurement of CD13, CD41/61 and CD62P expression on activated cells and heterotypic aggregate formation were established. Values were then compared before and after antigen challenge of RAO and healthy horses. Platelet adhesion to serum-coated plastic was measured as a functional marker of platelet activation.In vitro activation resulted in increased expression of neutrophil CD13 and platelet CD41/61 and CD62P. Activation of both cell types caused a significant increase in neutrophil–platelet aggregates.In horses with RAO, but not controls, there was a significant increase in the percentage of CD13 positive neutrophils at 10 h and 24 h and in the mean fluorescence intensity at 10 h. This was accompanied at 24 h by an increased mean platelet side scatter and thrombin-stimulated platelet adhesion.In conclusion, CD13 expression can be used as an indicator of equine neutrophil activation both in vitro and in vivo. Equine platelet activation in vitro can be detected by measuring CD41/61 or CD62P expression, and PAF-activated platelets and neutrophils form aggregates. However, despite evidence of circulating platelet activation, neither a change in expression of platelet activation markers, nor heterotypic aggregate aggregate formation could be detected.     

Feline Immunodeficiency Virus and Puma Lentivirus in Florida panthers (Puma concolor coryi): Epidemiology and Diagnostic Issues

This study documents the seroprevalence of feline immunodeficiency virus (FIV) and puma lentivirus (PLV) in free-ranging and captive Florida panthers (Puma concolor coryi) (n = 51) and translocated Texas cougars (P. concolor stanleyana) (n = 10) from 1985 to 1998. The sera were tested for anti-FIV antibodies by enzyme-linked immunosorbent assay (ELISA) and Western blot tests. The ELISAs were read kinetically (KELA) and the sera were retrospectively examined by PLV peptide ELISA. Eleven panthers and one cougar were positive by KELA; 4 panthers and 4 cougars were equivocal; 35 panthers and 5 cougars were negative; and 1 panther had no data. Seven of the 11 KELA-positive panthers were also positive by Western blot tests and all but one were positive by PLV peptide ELISA. Ten KELA-negative and Western blot-negative cats, were positive by PLV peptide ELISA. KELA results varied within cats from one sample period to the next, but PLV peptide ELISA results were consistent. Territorial sympatry and mating behaviour, noted from radiotelemetry location data on the cats, may have contributed to viral transmission between seropositive animals. These findings suggest that Florida panthers and the introduced Texas cougars have been exposed to FIV and/or PLV.     

Cytologic identification of immature endospores in a dog with rhinosporidiosis

An 8-year-old, intact, male Labrador Retriever was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with a 2-month history of severe sneezing episodes that resulted in epistaxis and bilateral sanguineous discharge. Rhinoscopy revealed a small polypoid mass, and specimens were obtained for histopathology. Microscopic examination of formalin-fixed tissue specimens revealed organisms consistent with Rhinosporidium seeberi. The mass was surgically excised and impression smears were made for cytology examination. Smears revealed high numbers of endospores, typical of those previously described for R seeberi. In addition, numerous smaller structures, presumed to be immature endospores, were noted. The immature endospores were morphologically distinct from mature endospores and have not been described previously. Recognition of immature forms of Rhinosporidium may help prevent misidentification of the organism or misdiagnosis of a dual infection.