Allergy Testing for Skin Disease in the Cat In Vivo vs In Vitro Tests

Abstract— The results of in vitro and in vivo tests for 36 cats with signs suggestive of allergic skin disease were compared. The cats were presented to the dermatology section of the Department of Veterinary Medicine, University of Bristol, with a variety of skin conditions. Intradermal skin testing with flea extract alone (six cats) or combined with a panel of 40 inhalant altergens (30 cats) was employed. Serum samples were tested with a commercial IgE ELISA against flea extract and 36 inhalant allergens. A diagnosis of flea bite hypersensitivity was made in 18 cats, atopic disease in nine cats and food hypersensitivity in one cat. Intradermal skin testing gave a positive predictive value in over 85 per cent of flea allergic cases and 100 per cent of atopic cases; the IgE ELISA test demonstrated relatively low predictive values for flea allergy and atopic disease and was not considered to be a useful diagnostic test. Résumé— Les résultats de tests in vitro et in vivo faits chez 36 chats ayant des symptômes évocateurs d'une dermite allergique ont été comparés. Des tests cutanés à la seule puce (six chats) ou combinés avec un panel de pneumallergènes (30 chats) ont été utilisés. Les sérums ont été testés avec un kit commercial de dosages d'IgE spécifiques de la puce et de 36 pneumallergènes par technique EIA. Un diagnostic de dermite par hyperseensibilité aux piqùres de puce a été fait chez 18 chats, une atopie chez neuf et une hypersensibilité d'origine alimentaire chez un. Les tests cutanés avaient une valeur prédictive de 85% pour les allergies à la puce et 100% pour les cas d'atopie; les tests IgE EIA avaient une valeur prédictive assez faible et n'ont pas été considérés comme étant un test utilisable en diagnostic. Resumen En este artículo se comparan los resultados de pruebas in vivo e in vitro efectuadas en 36 gatos con cuadro clínico indicativo de alergias cutáneas. Éstos animales fueron presentados en la sección de Dermatología del departamento de medicina de la Universidad de Bristol con una variedad de condiciones cutäneas. En las pruebas de invecciones intradérmicas se utilizaron alergenos de extracto de pulga solos o combinados con un panel de 40 alergenos inhalatorios (30 gatos). También se llevaron a cabo pruebas de suero con el test comercial de IgE ELISA para el extracho de pulga y 36 de los alergenos inhalatorios. En 18 de los gatos se diagnostico hipersensitividad a las pulgas, en nueve atopía y solo uno hipersensitividad a los alimentos. Las pruebas intradérmicas produjeron una predictividad positiva en 85% de los casos de alergia a las pulgas y 100% de los casos de atopía. Sin embargo el test ELISA de IgE produjo una baja predictividad relativa en los casos de hipersensitividad a las pulgas y casos de atopía y no se consideró como un test de gran utilidad diagnóstica.     

In Vitro Model for Testing Novel Implants for Equine Laryngoplasty

Objective— To develop an in vitro laryngeal model to mimic airflow and pressures experienced by horses at maximal exercise with which to test laryngoplasty techniques.
Study Design— Randomized complete block.
Sample Population— Cadaveric equine larynges (n=10).
Methods— Equine larynges were collected at necropsy and a bilateral prosthetic laryngoplasty suture was placed with #5 Fiberwire^™ suture to achieve bilateral maximal arytenoid abduction. Each larynx was positioned in a flow chamber and subjected to static flow and dynamic flow cycling at 2 Hz. Tracheal pressure and flow, and pressure within the flow chamber were recorded at a sampling frequency of 500 Hz. Data obtained were compared with the published physiologic values for horses exercising at maximal exercise.
Results— Under static flow conditions, the testing system produced inspiratory tracheal pressures (mean±SEM) of −33.0±0.98 mm Hg at a flow of 54.48±1.8 L/s. Pressure in the flow chamber was −8.1±2.2 mm Hg producing a translaryngeal impedance of 0.56±0.15 mm Hg/L/s. Under dynamic conditions, cycling flow and pressure were reproduced at a frequency of 2 Hz, the peak inspiratory (mean±SEM) pharyngeal and tracheal pressures across all larynges were −8.85±2.5 and −35.54±1.6 mm Hg, respectively. Peak inspiratory flow was 51.65±2.3 L/s and impedance was 0.57±0.06 mm Hg/L/s.
Conclusions— The model produced inspiratory pressures similar to those in horses at maximal exercise when airflows experienced at exercise were used.
Clinical Relevance— This model will allow testing of multiple novel techniques and may facilitate development of improved techniques for prosthetic laryngoplasty.     

In Vitro Biomechanical Comparison of Solid and Tubular Interlocking Nails in Neonatal Bovine Femurs

This study biomechanically evaluates solid and tubular interlocking nails in bovine neonatal femurs. Paired femurs from 40 neonatal dairy calves were obtained for mechanical testing. Intact femurs and four combinations of experimentally manipulated femurs (intact or ostectomized femurs with either a solid or tubular interlocking nail) were tested in craniocaudal and lateromedial bending, eccentric axial compression, and external torsion to evaluate composite rigidity, local/gap stiffness, and load to failure (compression and torsion only). In torsional composite rigidity, femurs with tubular interlocking nails were more compliant than intact femurs or intact femurs with solid interlocking nails (P <.001). Ostectomized femurs with solid interlocking nails were similar to intact femurs with tubular interlocking nails. Within femurs with tubular interlocking nails, ostectomized femurs were more compliant than intact femurs (P <.0001). In craniocaudal and lateromedial bending rigidity, ostectomized femurs were more compliant than intact femurs, regardless of interlocking nail type (P <.001). Within ostectomized femurs, tubular interlocking nails were more compliant than solid interlocking nails in craniocaudal bending (P <.05) and there was a similar trend in lateromedial bending (P=.06). In eccentric axial compression, local/ gap stiffness was significantly greater in intact femurs compared with intact femurs with solid (48% of intact bone) or tubular (45% of intact bone) interlocking nails and ostectomized femurs with solid (18% of intact bone) or tubular (11 % of intact bone) interlocking nails (P <.0001). In torsional testing, local/gap stiffness was not significantly different between intact femurs and intact femurs with interlocking nails, but was significantly lower in ostectomized femurs with solid (2% of intact bone) and tubular (0.2% of intact bone) interlocking nails (P <.0001). In torsional and compressive failure testing, plastic deformation of the tubular interlocking nail occurred at the unoccupied screw hole at the ostectomy site before bone failure. Interlocking nails should be considered as an optional repair method for neonatal bovine femoral fractures. Until the actual physiological loading characteristics of neonatal calf femurs are measured, it is uncertain whether solid or tubular interlocking nails tested in this study will provide sufficient strength and stiffness to stabilize neonatal bovine femoral fractures and facilitate healing.     

An In Vitro Biomechanical Investigation of the Mechanical Properties of Dynamic Compression Plated Osteotomized Adult Equine Tibiae

Objective — To determine the monotonic mechanical properties of osteotomized adult equine tibiae stabilized with two dynamic compression plates (DCP) and to compare the mechanical properties with those of intact tibiae and in vivo loads.
Study Design — The compressive, bending, and torsional mechanical properties of plated and intact tibiae were assessed in vitro.
Animals or Sample Population — Twelve pairs of adult equine tibiae.
Methods — Tibiae were loaded in axial compression, craniocaudal 3-point bending, or torsion in external rotation in a single cycle to failure. Mechanical properties were determined from load-displacement data.
Results — Compared to intact tibiae, the mean yield load, failure load and stiffness of plated tibiae were significantly lower ( P <.05) (compression and torsion); and the mean yield and failure bending moments, and bending stiffness, of the plated tibiae were lower ( P <.075 for yield), or significantly lower, respectively. The mean compression and bending yield loads for plated tibiae were greater than in vivo loads. The mean torsional yield load for plated tibiae approximated the torsional load determined for the adult horse at a walk.
Conclusions — Simple, anatomically reduced, DCP plated tibiae should have adequate strength to withstand immediate, postoperative in vivo compressive loads and bending moments placed on the tibia in vivo during immediate postoperative activities, however, may not have adequate torsional strength during immediate postoperative weight-bearing at a walk.
Clinical Relevance — Additional supportive methods, to decrease torsional loads, may be beneficial in maintaining stability of plate repaired tibiae during recovery from anesthesia and postoperative healing.     

Biomechanics of Cranial Cruciate Ligament Reconstruction in the Dog I. In Vitro Laxity Testing

Following an "over-the-top" reconstruction of the cranial cruciate ligament using fascia lata and the lateral one-third of the patellar ligament, joint instability was measured using an in vitro laxity testing device. Cranlocaudal drawer increased between zero and four weeks, then returned to initial values at 26 weeks.     

An In Vitro Biomechanical Study of a Multiplanar Circular External Fixator Applied to Equine Third Metacarpal Bones

The biomechanical characteristics of a 4-ring circular multiplanar fixator applied to equine third metacarpal bones with a 5 mm mid-diaphyseal osteotomy gap were studied. Smooth Steinmann pins, either 1/8 inch, 3/16 inch, or 1/4 inch, were driven through pilot holes in the bone in a crossed configuration and full pin fashion and fastened to the fixator rings using cannulated fixation bolts. The third metacarpal bone fixator constructs were tested in three different modes (cranial-caudal four-point bending, axial compression, and torsion). Loads of 2,000 N were applied in bending and axial compression tests and a load of 50 N ± m was applied during testing in torsion. Fixator stiffness was determined by the slope of the load displacement curves. Three constructs for each pin size were tested in each mode. Comparisons between axial stiffness, bending stiffness, and torsional stiffness for each of the three different pin sizes were made using one-way analysis of variance. There was no visually apparent deformation or permanent damage to the fixator frame, and no third metacarpal bone failure in any of the tests. Plastic deformation occurred in the 1/8 inch pins during bending, compression, and torsion testing. The 3/16 inch and 1/4 inch pins elastically deformed in all testing modes. Mean (±SE) axial compressive stiffness for the 1/8 inch, 3/16 inch, and 1/4 inch pin fixator constructs was: 182 ± 16 N/mm, 397 ± 21 N/mm, and 566 ± 8.7 N/mm; bending stiffness was 106 ± 3.3 N/mm, 410 ± 21 N/mm, and 548 ± 12 N/mm; and torsional stiffness was 6.15 ± 0.82 N.m/degree, 7.14 ± 0.0 N±m/degree, and 11.9 ± 1.0 N.m/degree respectively. For statically applied loads our results would indicate that a 4-ring fixator using two 1/4 inch pins per ring may not be stiff enough for repair of an unstable third metacarpal bone fracture in a 450 kg horse.     

An In Vitro Biomechanical Investigation of an Interlocking Nail for Fixation of Diaphyseal Tibial Fractures in Adult Horses

The compressive, bending and torsional mechanical properties of osteotomized adult equine tibiae stabilized with an interlocking intramedullary nail (nail-tibia composite) were compared with those of intact tibiae to determine the clinical applicability of the nail for repair of tibial fractures in adult horses. The mean yield load, failure load, and stiffness for the nail-tibia composites were significantly less ( P < .05) than those for the intact tibiae in all loading configurations. The mean compressive yield load for the nail-tibia composites was greater than the compressive load calculated from previously reported in vivo data for walking and trotting, and was equal to the load calculated for recovery from anesthesia. The mean yield bending moment for the nail-tibia composites was greater than the bending moment previously calculated for standing, walking, and recovery from anesthesia. The mean torsional yield load for the nail-tibia composites was less than the torsional load determined for the walk from another in vivo study. The design of the interlocking nail evaluated in the present study should be modified to increase torsional and compressive yield strengths and torsional stiffness before reasonable success could be expected for the treatment of adult equine tibial fractures.     

An In Vitro Biomechanical Comparison of Two Fixation Methods for Transverse Osteotomies of the Medial Proximal Forelimb Sesamoid Bones in Horses

OBJECTIVE: This study compared the mechanical properties of the normal intact suspensory apparatus and two methods of fixation for repair of transverse, midbody fractures of the proximal sesamoid bones of adult horses: transfixation wiring (TW) and screws placed in lag fashion (LS). STUDY DESIGN: An in vitro, paired study using equine cadaver limbs mounted in a loading apparatus was used to test the mechanical properties of TW and LS. ANIMAL OR SAMPLE POPULATION: Seventeen paired (13 repaired, 4 normal) equine cadaver limbs consisting of the suspensory apparatus third metacarpal bone, and first and second phalanges. METHOD: The two methods of repair and normal intact specimens were evaluated in single cycle-to-failure loading. Yield failure was defined to occur at the first notable discontinuity (>50 N) in the load-displacement curve, the first visible failure as evident on the videotape, or a change in the slope of the moment-fetlock angle curve. Ultimate failure was defined to occur at the highest load resisted by the specimen. Corresponding resultant force and force per kg of body weight on the suspensory apparatus, fetlock joint moment, and angle of fetlock dorsiflexion were calculated by use of specimen dimensions and applied load. These were compared along with specimen stiffness, and ram displacement. RESULTS: Load on the suspensory apparatus, load on the suspensory apparatus per kg of body weight, moment, applied load, and angle of fetlock dorsiflexion at yield failure were significantly greater for the TW-repaired than for the LS-repaired specimens. A 3 to 5 mm gap was observed before yield failure in most TW-repaired osteotomies. CONCLUSIONS: Transfixation wiring provided greater strength to yield failure than screws placed in lag fashion in single cycle load-to-failure mechanical testing of repaired transverse osteotomized specimens of the medial proximal forelimb sesamoid bone.     

In Vitro Biomechanical and Histological Assessment of Pilot Hole Diameter for Positive-Profile External Skeletal Fixation Pins in Canine Tibiae

This study was conducted to evaluate the effect of pilot hole (PH) diameter (0, 1.5, 2.0, 2.7, 3.1, 3.3, 3.5, and 3.7 mm) on the biomechanical and microstructural performance of positive-profile threaded external skeletal fixation pins (3.18 mm inner diameter, 3.97 mm outer diameter) using cadaveric canine tibiae. Eight pins per pilot hole diameter (four pins per bone) were used to assess differences in end-insertional torque and pin pull-out strength. Histological evaluation of eight bicortical pin tracts per pilot hole diameter was accomplished using computer-interfaced videomicroscopy on specimens processed using a bulk-staining technique. Compared with no predrill, use of 2.7 mm PH increased end-insertional torque and pull-out strength by 25% and 13.5%, respectively. No significant differences were observed in biomechanical variables for the PH diameter range of 2.0 to 3.1 mm. Compared with no predrill, use of a 3.1 mm PH increased thread area by 18%. Microfracturing around the threads decreased as PH diameter increased. Damage to the interface at the entry and exit sites of both near and far cortices also decreased as PH diameter increased. It was concluded that predrilling a PH whose diameter approximates, but does not exceed the inner diameter of the positive profile pin will not only improve initial pin stability compared with no predrilling, but it will also reduce microstructural damage that may lead to excessive bone resorption and premature pin loosening.     

Shrimp Antimicrobial Testing. I. In Vitro Susceptibility of Thirteen Gram-Negative Bacteria to Twelve Antimicrobials

Abstract

Standard minimum inhibitory concentration (MIC) studies were conducted in vitro on eleven prospective antimicrobials and one reference antimicrobial. The compounds were tested against a standardized battery of 13 gram-negative bacterial isolates associated with shrimp disease. Two additional bacterial organisms not associated with shrimp, Escherichia coli and Pseudomonas aeruginosa, were also tested as system controls. The compounds tested were chloramphenicol (reference), enrofloxacin, erythromycin, florfenicol, oxytetracycline, paromomycin, four experimental fluoroquinolines (PD124816, PD127391, PD131628, PD132133), Romet-30®, and Sarafin®. All compounds, with the possible exception of paromomycin, had significantly better overall MIC ranges than did chloramphenicol.     

Influence of Cysteamine on In Vitro Maturation, In Vitro and In Vivo Fertilization of Equine Oocytes

The effect of cysteamine on in vitro nuclear and cytoplasmic maturation of equine oocytes collected by transvaginal ultrasound guided follicular aspiration was assessed. Oocytes were matured in vitro with (cysteamine group) or without (control group) cysteamine. The nuclear stage after DNA Hoechst staining, penetration rates after two different in vitro fertilization (IVF) techniques (IVF media with ionophore and Hepes buffer with heparin) and the embryo yield following oocyte intra-oviductal transfer were used as a criterion for assessing nuclear and cytoplasmic maturation, respectively. Contrary to the data described in other domestic species, there was no effect of cysteamine on in vitro nuclear maturation, IVF or in vivo embryonic development under our conditions. Ovum pick up yields (52%) and maturation rates (control group: 47% and cysteamine group: 55%) were similar to those previously reported. From 57 oocytes transferred to the oviduct in each group, the number of embryos collected was 10 (17%) in the control group and five in the cysteamine group (9%). Those two percentages were not statistically different (p > 0.05). No effect of IVF technique was seen on the success rate (6%) in each group.     

An In Vitro Biomechanical Comparison of an Interlocking Nail System and Dynamic Compression Plate Fixation of Ostectomized Equine Third Metacarpal Bones

OBJECTIVE: To compare the mechanical properties of two stabilization methods for ostectomized equine third metacarpi (MC3): (1) an interlocking nail system and (2) two dynamic compression plates. Animal or Sample Population-Ten pairs of adult equine forelimbs intact from the midradius distally. METHODS: Ten pairs of equine MC3 were divided into two test groups (five pairs each): caudocranial four-point bending and torsion. Interlocking nails (6 hole, 13-mm diameter, 230-mm length) were placed in one randomly selected bone from each pair. Two dynamic compression plates one dorsally (12 hole, 4.5-mm broad) and one laterally (10 hole, 4.5-mm broad) were attached to the contralateral bone from each pair. All bones had 1 cm mid-diaphyseal ostectomies. Five construct pairs were tested in caudocranial four-point bending to determine stiffness and failure properties. The remaining five construct pairs were tested in torsion to determine torsional stiffness and yield load. Mean values for each fixation method were compared using a paired t-test within each group. Significance was set at P<.05. RESULTS: Mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite, respectively, in four-point bending were: composite rigidity, 3,454+/-407.6 Nm/rad and 3,831+/-436.5 Nm/rad; yield bending moment, 276.4+/-40.17 Nm and 433.75+/-83.99 Nm; failure bending moment, 526.3+/-105.9 Nm and 636.2+/-27.77 Nm. There was no significant difference in the biomechanical values for bending between the two fixation methods. In torsion, mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite were: composite rigidity, 124.1+/-16.61 Nm/rad and 262.4+/-30.51 Nm/rad; gap stiffness, 222.3+/-47.32 Nm/rad and 1,557+/-320.9 Nm/rad; yield load, 94.77+/-7.822 Nm and 130.66+/-20.27 Nm, respectively. Composite rigidity, gap stiffness, and yield load for double plate fixation were significantly higher compared with interlocking nail fixation in torsion. CONCLUSIONS: No significant differences in biomechanical properties were identified between an interlocking nail and double plating techniques for stabilization of ostectomized equine MC3 in caudocranial four-point bending. Double plating fixation was superior to interlocking nail fixation in torsion.     

牛体外受精胚胎的体外培养研究进展

家畜体外受精（IVF）技术自上世纪八十年代获得成功以来，发展十分迅速，九十年代已进入试管胚的开发应用阶段。目前，IVF胚胎的质量与体内胚相比仍有很大差距。在进行IVF胚胎体外培养时，常会出现“体外发育阻断”现象，主要表现为细胞数较少、卵裂球形状不规则、存在死亡的细胞和细胞质碎片、发育速率和抗冻性降低以及酶活性和营养物摄取的改变等方面。近年来，为了克服胚胎体外发育所存在的某些缺陷，国内、外对不同动物的胚胎体外培养体系和培养方法进行了系统研究，取得了长足进展。本文就牛IVF胚胎体外培养方面的研究进展综述如下。     

In Vitro Cerclage Wiring Analysis

The ability of six different instruments to apply a cerclage wire under tension to a tension gage was compared. The loop knot produced greater final wire tension than the twist knot, both before and after bending. No significant difference in tension was found between the Swiss Osteo and A.S.I.F. instruments. The Rhinelander and Richards instruments gave approximately the same tension before the bend. The Rhinelander, Richards, and Vise Grip instruments showed no statistical difference in tension produced after the bend. The Bowen instrument developed the least amount of tension, both before and after bending the twist. All twist knots lost a significant amount of tension during the bending process. The twist-type knots that were twisted until breakage in the middle of the knot produced greater tension than those that were cut once they were tight. Cutting the twisted knot caused a significant decrease in wire tension. No correlation was found between operator pull and final cerclage wire tension.     

猪胚胎的体外生产技术

应用体外受精技术,可以有效地利用屠宰的青年母猪卵巢巾的未成熟卵,大量、廉价地实验室生产胚胎。这对加速我国良种猪群的繁殖是一项行之有效的胚胎工程技术。借鉴国内外实验室生产猪胚胎的经验及根据我们实验室的实践,本文比较详细地叙述了体外受精猪胚胎的生产过程,包括卵母细胞的获得、培养、精子获能、体外受精以及受精后的体外培养、冷冻保仃与移植等。