Effects of Nylon and Polyglactin 910 Suture Material on Perilimbal Corneal Wound Healing in the Dog

The effects of fine suture materials on corneal wound healing in the dog were studied. In 20 dogs, standardized perforating perilimbal clear corneal wounds were made and closed with either monofilament Polyglactin 910 or nylon. Five dogs each were euthanized 8,12,16, and 21 days postoperatively. Results of gross, biomicroscopic, and histologic examinations at 8,12,16, and 21 days showed nylon and Polyglactin 910 to cause similar inflammatory responses. Epithelialization and suppuration around the suture tracts were observed more frequently when Polyglactin 910 was used. Both materials were associated with a foreign body (granulomatous) response. There was no loss of wound integrity with either material. Strengths of the incised corneal tissues with and without the sutures intact were determined. At day 16 postsurgery, there was a statistically significant difference in tissue strengths between cases in which sutures were and were not intact. This difference was not apparent at 21 days postsurgery, which suggested that the suture dependent phase ends between the 16th and 21st postsurgical days. In addition, at day 16 there was no statistical difference between the tissue strength of wounds sutured with nylon or Polyglactin 910. Corneal suture materials studied should remain in place for at least 16 days, and absorbable material is only appropriate if it retains tensile strength for 16 days.     

Modulation of nociceptive withdrawal reflexes evoked by single and repeated nociceptive stimuli in conscious dogs by low-dose acepromazine

ObjectivesTo investigate the modulation of the nociceptive withdrawal reflex (NWR) and temporal summation (TS) by low‐dose acepromazine (ACP) in conscious dogs. To assess the short‐ and long‐term stability of the reflex thresholds.Study designRandomized, blinded, placebo‐controlled cross‐over experimental study.AnimalsEight adult male Beagles.MethodsThe NWR was elicited using single transcutaneous electrical stimulation of the ulnar nerve. Repeated stimuli (10 pulses, 5 Hz) were applied to evoke TS. The responses of the deltoideus muscle were recorded and quantified by surface electromyography and the behavioural reactions were scored. Each dog received 0.01 mg kg^?1 ACP or an equal volume saline intravenously (IV) at 1 week intervals. Measurements were performed before (baseline) and 20, 60 and 100 minutes after drug administration. Sedation was scored before drug administration and then at 10 minutes intervals. Data were analyzed with Friedman repeated measures analysis of variance on ranks and Wilcoxon signed rank tests.ResultsAcepromazine resulted in a mild tranquilization becoming obvious at 20 minutes and peaking 30 minutes after injection. Single (I_t) and repeated stimuli (TS_t) threshold intensities, NWR and TS characteristics and behavioural responses were not affected by the ACP at any time point. Both I_t and TS_t were stable over time.Conclusions and clinical relevanceIn dogs, 0.01 mg kg^?1 ACP IV had no modulatory action on the NWR evoked by single or repeated stimuli, suggesting no antinociceptive activity on phasic nociceptive stimuli. The evidence of the stability of the NWR thresholds supports the use of the model as an objective tool to investigate nociception in conscious dogs. A low dose of ACP administered as the sole drug, can be used to facilitate the recordings in anxious subjects without altering the validity of this model.     

High-power directional emission from microlasers with chaotic resonators

High-power and highly directional semiconductor microcylinder lasers based on an optical resonator with deformed cross section are reported. In the favorable directions of the far-field, a power increase of up to three orders of magnitude over the conventional circularly symmetric lasers was obtained. A "bow-tie"-shaped resonance is responsible for the improved performance of the lasers in the higher range of deformations, in contrast to "whispering-gallery"-type modes of circular and weakly deformed lasers. This resonator design, although demonstrated here in midinfrared quantum-cascade lasers, should be applicable to any laser based on semiconductors or other high-refractive index materials.     

Local Control of Microdomain Orientation in Diblock Copolymer Thin Films with Electric Fields

Local control of the domain orientation in diblock copolymer thin films can be obtained by the application of electric fields on micrometer-length scales. Thin films of an asymmetric polystyrene-polymethylmethacrylate diblock copolymer, with cylindrical polymethylmethacrylate microdomains, were spin-coated onto substrates previously patterned with planar electrodes. The substrates, 100-nanometer-thick silicon nitride membranes, allow direct observation of the electrodes and the copolymer domain structure by transmission electron microscopy. The cylinders aligned parallel to the electric field lines for fields exceeding 30 kilovolts per centimeter, after annealing at 250°C in an inert atmosphere for 24 hours. This technique could find application in nanostructure fabrication.     

Purification of secretory immunoglobulin A from milk of the brushtail possum (Trichosurus vulpecula)

AIM: To identify and purify secretory immunoglobulin A (sIgA), a key effecter molecule in mucosal immune responses, from milk of the brushtail possum (Trichosurus vulpecula).

METHODS: Milk samples were collected from female possums with pouch young, and clarified by centrifugation and precipitation methods. The clarified fraction was purified by gel filtration and affinity chromatography to yield sIgA. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques were used to assess the purity of the final product, and to identify the heavy (H) chain, light (L) chain and secretory component (SC) of possum sIgA.

RESULTS: Immunoblotting, using antibodies raised against cloned possum sIgA SC and H-chain, and a synthetic peptide fragment of the H-chain, confirmed the identity of the purified protein. The N-terminal amino acid sequence of purified possum sIgA showed strong homology to reported sequences of H-chain variable regions of marsupial immunoglobulins.

CONCLUSIONS: Milk was shown to be a convenient source of mucosal secretion containing sIgA, and a process involving 2 precipitation and 2 chromatography steps produced purified sIgA. This IgA preparation will prove useful for the generation of sIgA-specific immunological reagents for measurement of immune responses in the development of mucosal-based vaccines for biological control of possums.     

Unilateral Seminoma in a Dromedary Camel

A 10‐year‐old, clinically healthy, male dromedary camel had presented a history of progressive unilateral testicular enlargement over the past 5 years. The animal had mated with 32 females during that period; all had conceived. The sex ratio of his offspring was one male to 31 females. Ultrasound examination of the right testicle revealed a diffusely heterogeneous parenchyma with no identifiable normal testicular tissue. The enlarged testicle was surgically removed. Macroscopically, the testicle had a glistening pink surface and contained multiple soft, bulging nodules. Histopathologically, a well‐differentiated, diffuse seminoma was diagnosed. In conclusion, this study describes the fertility, sex ratio, clinical findings and ultrasonographic imaging in a male dromedary camel affected with unilateral testicular seminoma.     

Comparison of characteristics of actomyosin from white, pink, and red muscle fiber types in cultured carp

ABSTRACT: The present study compared and examined the characteristics of actomyosin among white (W), pink (P), and red (R) muscle fiber types in carp (cultured). Both the superprecipitation reaction and the Mg²⁺-ATPase activity of actomyosin became higher with increased Ca²⁺ concentration (pCa 7.0–pCa 5.0) and with decreased adenosine triphosphate (ATP) concentration (3.0–0.5 mM) in all three muscle fiber types. A comparison of the three fiber types shows that the superprecipitation reaction of actomysoin was lower in the order of W < P < R and, in contrast, was higher for Mg²⁺-ATPase activity in the order of W > P > R. A significantly positive correlation between both values was found for each of the three muscle fiber types, but these correlations were clearly different among the three muscle fiber types, and the superprecipitation reaction of actomyosin was lower in the order of W < P < R when Mg²⁺-ATPase activity was at the same level. In conclusion, the characteristics of actomyosin were remarkably different among white, pink, and red muscle fiber types.     

Bilateral Calcaneal Epiphysiolysis in a Dog

Ununited epiphyses were seen in the calcanei of a 13-month-old Rottweiler with abnormal rear limb conformation. Histologic examination of the tissues showed a nonunion with neoarthrosis formation. Surgical management included use of tension band and lag screw techniques to achieve epiphysiodesis that was radiographically evident 12 weeks postsurgery. There was no sign of lameness when examined 8 months after surgery. Similarities exist between this case and that of osteochondrosis in other domestic species, and with Osgood-Schlatters disease in humans. Osteochondrosis and/or abnormal angulation of the hocks were suspected as the underlying cause of the epiphyseal separations.     

Correlation of Blood Flow of the Preovulatory Follicle to its Diameter and Endocrine Profile in Dairy Buffalo

Blood flow of the preovulatory follicle (POF) wall can be used as a predictor of the quality of POF. Our aim was to determine the correlation of blood flow of POF with the POF diameter, and intra‐follicular and plasma concentrations of Insulin‐like Growth Factor‐I (IGF‐1) and oestradiol in dairy buffalo. Nine Murrah buffalo subjected to an ovulation synchronization protocol (Ovsynch) were assessed on day 10 of the protocol for diameter and blood flow of POF, followed by the aspiration of follicle fluid. Prior to follicular aspiration, blood samples were obtained from jugular vein for estimation of IGF‐1 and oestradiol. The vascularity of POF was determined (Range: 250–967 pixel²) along with intra‐follicular and plasma concentration of IGF‐1 (Range: 9.3–31.8 ng/ml and 14.7–29.7 ng/ml respectively) and oestradiol (Range: 124.2–447.9 ng/ml and 0.25–1.05 ng/ml respectively). Diameter of the POF was weakly correlated (r = 0.21, p < 0.01) with blood flow to it. As compared to POF diameter, the blood flow of POF had greater positive correlation with intra‐follicular and plasma concentrations of hormones (IGF‐1 and oestradiol). A strong positive correlation was recorded between intra‐follicular IGF‐1 and oestradiol. Also, plasma concentrations of oestradiol and progesterone were negatively correlated In brief, assessment of the blood flow of the POF is a non‐invasive and reliable indicator of its functional competence as compared to the POF diameter.