Onfaloarterioflebite e onfalectomia em bezerro / Omphalophlebitis, omphaloarteritis and omphalectomy in a calf

O objetivo desse trabalho foi relatar um caso de onfaloarterioflebite em bezerro mestiço com oito dias de vida, apresentando aumento de volume umbilical associado à miíase. O hemograma revelou neutrofilia e hiperfibrinogenemia, sendo realizado também exame ultrassonográfico para avaliação do comprometimento de estruturas internas e confirmação diagnóstica. Devido à gravidade do quadro, optou-se pelo tratamento cirúrgico do animal, através da técnica de onfalectomia. No transoperatório, foi instituída terapêutica com antimicrobiano, antipirético, analgésico e mucolítico, além do internamento do paciente para continuidade da terapia sistêmica e realização de curativos. Após 72h da cirurgia, observou-se excelente cicatrização da ferida operatória e novos exames laboratoriais detectaram ausência de neutrofilia e hiperfibrinogenemia, possibilitando a alta médica, com recomendações de curativos diários na propriedade e retorno, após 10 dias, para reavaliação e retirada dos pontos. Este estudo reportou os achados clínicos e a abordagem terapêutica em um caso de onfaloarterioflebite em bezerro. A anamnese e o exame físico são fundamentais para o diagnóstico de onfalopatias e, quando associados à exames complementares, permitem ao veterinário a determinação das estruturas afetadas, possibilitando a instituição do tratamento mais eficiente e específico. O procedimento cirúrgico é um método terapêutico que apresenta resultados mais rápidos e melhores taxas de recuperação quando comparado ao tratamento clínico de forma isolada.

The objective of this study was to report a case of omphaloarteriophlebitis in an eight-day-old crossbred calf, presenting an increase in umbilical volume associated with myiasis. The blood count revealed neutrophilia and hyperfibrinogenemia, and an ultrasound examination was also performed to assess the impairment of internal structures and diagnostic confirmation. Due to the severity of the condition, we opted for the surgical treatment of the animal, using the omphalectomy technique. In the intraoperative period, therapy with antimicrobial, antipyretic, analgesic and mucolytic agents was instituted, in addition to the patient's hospitalization for continuity of systemic therapy and dressings. After 72 hours of surgery, excellent healing of the surgical wound was observed and new laboratory tests detected the absence of neutrophilia and hyperfibrinogenemia, allowing medical discharge, with recommendations for daily dressings on the property and return, after 10 days, for reassessment and removal of stitches. This study reported the clinical findings and therapeutic approach in a case of omphaloarteriophlebitis in a calf. Anamnesis and physical examination are fundamental for the diagnosis of omphalopathies and, when associated with complementary exams, allow the veterinarian to determine the affected structures, enabling the institution of the most efficient and specific treatment. The surgical procedure is a therapeutic method that presents faster results and better recovery rates when compared to clinical treatment alone.

Neonatal nephron loss during active nephrogenesis results in altered expression of renal developmental genes and markers of kidney injury.

Preterm neonates are at a high risk for nephron loss under adverse clinical conditions. Renal damage potentially collides with postnatal nephrogenesis. Recent animal studies suggest that nephron loss within this vulnerable phase leads to renal damage later in life. Nephrogenic pathways are commonly reactivated after kidney injury supporting renal regeneration. We hypothesized that nephron loss during nephrogenesis affects renal development, which, in turn, impairs tissue repair after secondary injury. Neonates prior to 36 wk of gestation show an active nephrogenesis. In rats, nephrogenesis is ongoing until day 10 after birth. Mimicking the situation of severe nephron loss during nephrogenesis, male pups were uninephrectomized at day 1 of life (UNXd1). A second group of males was uninephrectomized at postnatal day 14 (UNXd14), after terminated nephrogenesis. Age-matched controls were sham operated. Three days after uninephrectomy transcriptional changes in the right kidney were analyzed by RNA-sequencing, followed by functional pathway analysis. In UNXd1, 1,182 genes were differentially regulated, but only 143 genes showed a regulation both in UNXd1 and UNXd14. The functional groups "renal development" and "kidney injury" were among the most differentially regulated groups and revealed distinctive alterations. Reduced expression of candidate genes concerning renal development (Bmp7, Gdnf, Pdgf-B, Wt1) and injury (nephrin, podocin, Tgf-ß1) were detected. The downregulation of Bmp7 and Gdnf persisted until day 28. In UNXd14, Six2 was upregulated and Pax2 was downregulated. We conclude that nephron loss during nephrogenesis affects renal development and induces a specific regulation of genes that might hinder tissue repair after secondary kidney injury.

S-ketamine and intranasal application: alternatives for the castration of male suckling piglets?

BACKGROUND: The intramuscular injection of ketamine and azaperone was proposed as a suitable anaesthesia for male suckling piglets for surgical castration. However, this can be opposed by massive defensive movements, hypothermia and tachycardia during castration and a long recovery period. The aim of the present study was to test whether the use of S-ketamine and/or a change in the route of application from intramuscular to intranasal could reduce stress responses and the duration of recovery compared to the intramuscular route and the use of racemic ketamine. Seventy-eight healthy, five-day-old male piglets were randomized to six treatment groups in a blinded experimental study, matched by litter and weight. Experimental groups were A (15 mg kg-1 S-ketamine + 2 mg kg-1 azaperone, i.m., surgical castration), B (15 mg kg-1 R/S-ketamine racemate + 2 mg kg-1 azaperone, i.m., surgical castration), C (30 mg kg-1 S-ketamine + 2 mg kg-1 azaperone, i.n., surgical castration), D (15 mg kg-1 R/S-ketamine racemate + 2 mg kg-1 azaperone, i.m.; not castrated), E (positive control group; no anesthesia, surgical castration) and F (negative control group; no anesthesia, not castrated). RESULTS: S-ketamine reduced the defensive movement score during castration to a similar extent to racemic ketamine when administered intramuscularly but not via the intranasal route. However, the effects of S-ketamine (both routes) on the increase in cortisol levels and decrease in body temperature were similar to those induced by racemic ketamine. A reduction of the long recovery time known for ketamine-azaperone anaesthesia could not be achieved with S-ketamine in the given dosage, regardless of the route of application. The intranasal administration of ketamine was difficult with the available formulation as the necessary amount exceeded the capacity of the nose cavity. CONCLUSIONS: Neither the use of S-ketamine nor intranasal administration can be suitable alternatives for the anaesthesia of male suckling piglets for castration.

A surgical mouse model of neonatal pressure overload by transverse aortic constriction.

Cardiac disease is the main cause of death worldwide. Insufficient regeneration of the adult mammalian heart is a major driver of cardiac morbidity and mortality. Cardiac regeneration occurs in early postnatal mice, thus understanding mechanisms of mammalian cardiac regeneration could facilitate the development of novel therapeutic strategies. Here, we provide a detailed description of a neonatal mouse model of pressure overload by transverse aortic constriction (nTAC) that can be applied at postnatal days 1 and 7. We have previously used this model to demonstrate that mice are able to fully adapt to pressure overload following nTAC on postnatal day 1. In contrast, when nTAC is applied in the non-regenerative phase (at postnatal day 7), it is associated with a maladaptive response similar to that seen when transverse aortic constriction (TAC) is applied to adult mice. Once a user is experienced in nTAC surgery, the procedure can be completed in less than 10 min per mouse. We anticipate that this model will facilitate the discovery of therapeutic targets to treat patients or prevent pressure overload-induced cardiac failure in the future.

Effects of Oral Meloxicam and Topical Lidocaine on Pain associated Behaviors of Piglets Undergoing Surgical Castration.

The objective of this study was to find a practical means of reducing pain associated with surgical castration by evaluating the effects of oral meloxicam and topical lidocaine, separately and in combination, on behavioral indicators of pain in piglets. Two hundred thirty-five piglets were surgically castrated between three and seven days of age. Immediately following castration, piglets received one of four treatments: (1) No pain mitigation (C; control; n = 58); (2) NSAID only (M; meloxicam; n = 59); (3) Topical anesthetic (L; lidocaine spray; n = 60); or (4) NSAID and topical anesthetic (X; meloxicam and lidocaine spray; n = 59). Behaviors were recorded by direct observation of individual piglets using five-minute scan samples over a five-hour period, for three days post-castration. Results of the experiment demonstrate the administration of oral meloxicam and topical lidocaine spray at the time of castration under the current methods did not mitigate pain associated with the procedure (P = 0.09; C: 2.1 ± 0.1, L: 2.4 ± 0.1, M: 2.1 ± 0.1 and X: 2.1 ± 0.1).

Topical vapocoolant spray reduces nociceptive response to ear notching in neonatal piglets.

OBJECTIVE: To evaluate the efficacy of a vapocoolant spray (VS) to provide local anaesthesia for piglets during ear notching. STUDY DESIGN: Randomized study. ANIMALS: Eleven 10 day old and forty 3-5 day old Large White piglets. METHODS: Temperature validation studies using thermocouples and a temperature data logger were conducted on dead and live tissue to determine optimal spray distance and duration to reduce tissue temperature to below 10 °C. A behavioural trial was conducted to assess efficacy for ear notching. Piglets were randomly assigned to one of four treatment groups: positive control (POS; n = 10), VS (n = 10), lignocaine (LIG; n = 10) and negative control (NEG; n = 10). Spray was administered to the margin of each ear, from a distance of 10 cm, and for a duration of 2 seconds immediately prior to ear notching. Behavioural observation was used to assess movement and vocal response, with responses categorized as no response (0) and response (1). RESULTS: Temperature and tissue validation studies indicated that a 2 second spray from 10 cm reduced tissue temperature to below 10 °C, and reduced response to stimulation of the skin with an 18 gauge needle (p < 0.001). There was a significant effect of treatment on response to ear notching (p < 0.001). The probability of a piglet to respond to ear notching was 98.7% for NEG piglets, compared with those treated with VS (5.3%), LIG (1.1%) and sham-notched piglets (0.9%). CONCLUSIONS AND CLINICAL RELEVANCE: This study contributes new data on the pain of ear notching in piglets. The application of a topical VS prior to ear notching reduced the antinociceptive response of piglets to the procedure, similar to that of a local anaesthetic. Cryoanaesthesia presents a simple and effective option for reducing the pain response to this simple husbandry procedure.

Evaluation of sutureless scrotal castration for pediatric and juvenile dogs.

OBJECTIVE To determine complication rates associated with sutureless scrotal castration (SLSC) performed in a large number of pediatric and juvenile dogs and investigate whether procedure duration differed from that of traditional prescrotal castration (TPSC). DESIGN Prospective case series and clinical trial. ANIMALS 400 shelter-owned dogs that underwent SLSC and 18 shelter-owned dogs that underwent TPSC between 2 and 5 months of age. PROCEDURES In the first phase of the study, SLSC was performed for 400 dogs, which were monitored for ≥ 24 hours after surgery to identify surgery-related complications such as hemorrhage, signs of pain, self-trauma, swelling, and dermatitis at the incision site. In the second phase, the durations of 18 SLSC and 18 TPSC procedures were measured and compared. RESULTS No hemorrhage-related complications were identified in any dog during SLSC in the first phase. Complications were all minor and self-limiting and included peri-incisional dermatitis (9/400 [2.3%]), skin bruising (4/400 [1.0%]), and swelling (1/400 [0.3%]). No self-trauma was observed for any dog, nor did any dog require additional analgesic treatment after surgery. Procedure duration was significantly briefer for SLSC (mean ± SD, 1.0 ± 0.2 minutes) than for TPSC (3.5 ± 0.4 minutes). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that SLSC as evaluated was safe and significantly faster than TPSC when performed in healthy 2- to 5-month-old dogs. The SLSC technique has the potential to improve morbidity and mortality rates as well as financial costs associated with castration, particularly in high-quality, high-volume spay and neuter programs.

Effect of transmucosal corn syrup application on postoperative blood glucose concentrations in kittens.

Objectives The aim of the study was to determine the effect of a common clinical practice, the transmucosal (TM) application of corn syrup, on postoperative blood glucose concentrations in kittens. Methods This study was designed as a randomized controlled trial. Seventy-five kittens between the age of 8 and 16 weeks scheduled for surgical sterilization by gonadectomy at an animal shelter were enrolled. Kittens were randomly assigned to either a routine treatment group that received the shelter's typical postoperative application of corn syrup immediately following gonadectomy or to a control group that did not receive typical treatment. Three blood glucose measurements were obtained per kitten: baseline reading prior to preoperative examination, immediately postoperatively and 20 mins postoperatively. The median values of the 20 min postoperative blood glucose reading for the control and treatment groups were compared using the Wilcoxon rank-sum test. Results Postoperative application of corn syrup to the oral mucosa of kittens did not result in significant elevations in blood glucose compared with controls. No kitten was hypoglycemic (⩽60 mg/dl) at any point during the study. Conclusions and relevance TM application of corn syrup did not affect postoperative blood glucose concentrations in kittens. Protocols that use routine TM administration of corn syrup in kittens should be re-evaluated.

Internal fixation of fractured ribs in neonatal foals with nylon cable tie using a modified technique.

Nylon cable tie has been shown to be an effective and economical method for fixing fractured ribs in the neonatal foal. This article describes a modification of the previously described technique. Under general anesthesia, the fractured ribs were exposed and a hole was drilled in the dorsal and ventral fragments. The fracture was not reduced, leaving the fragments overriding each other. The nylon cable tie was passed through the hole in the dorsal fragment from the external surface of the rib. The free end of the cable tie was then passed through the hole in the ventral fragment from the external surface of the rib and the tie was tightened. This technique was used in 4 neonatal foals with no complications. The modification of the original technique represents a method to minimize soft tissue trauma, implant failure, and complications.

Technique modifiée pour la fixation interne de fractures de côtes chez le poulain nouveau-né avec des attaches de câbles en nylon. Cet article décrit une technique pour réparer les fractures de côtes chez le poulain nouveau-né en utilisant des attaches de câbles en nylon. Sous anesthésie générale, une incision verticale a été faite et les côtes fracturées ont été exposées. Une mèche de perceuse a été utilisée pour faire des trous dans les fragments dorsaux et ventraux des côtes fracturées, approximativement 5 à 10 mm de la ligne de fracture. Le câble a été introduit dans le trou du fragment dorsal et ensuite dans le trou du fragment ventral. Les attaches de câbles ont été resserrées. Les fractures n'ont pas été réduites et les fragments dorsaux chevauchaient les fragments ventraux. Cette technique a été utilisée sans complications chez quatre poulains nouveau-nés.(Traduit par les auteurs).

Neonatal pinealectomy in rats - a simple micro-suction technique.

To determine the role of the pineal gland and its secretory product melatonin on various aspects of the functioning of the organism, the gland can be easily surgically removed in rats within 18 hours after birth. We performed pinealectomy in rats in a state of deep hypothermia under an operating microscope, using a micro-suction device of our own construction. The rats were induced into a state of suspended animation by placing them in the freezing compartment at minus 20 Celsius degrees. The cessation of respiration and heart beat lasted for about 15 minutes. During that time the pinealectomy was performed. In some cases there was minor hemorrhage that was easily controlled. There were no major side effects or mortality following surgery. All rats recovered within 15 minutes after the end of the procedure. The pinealectomy procedure described in this study is simple, rapid, effective and safe, and can be easily performed with instruments commonly available in most laboratories.

Routine Trimming and Therapeutic Farriery in Foals.

Hoof care in the first few months of life is serious business and should never be taken lightly. Farriery plays a vital role in both the development of the hoof and the conformation of the limb. Management of the feet and limbs during this period will often dictate the success of the foal as a sales yearling or mature sound athlete. A sound foot care program is time-consuming, whereas assembly-line trimming is quick and easy, but the former is much more beneficial.

Congenital multiple arthrogryposis in bovine / Artrogripose congênita múltipla em bovino

This report describes an anal atresia, anatomical urethra alteration (slightly caudal to the udder), thickened joints, and changes in the pelvis in a newborn Holstein cow. Visualization of the final portion of the rectum was not possible by perineal access and laparotomy through the right flank was performed in order for abdominal exploration and colostomy attempt. During the surgical procedure visceral rupture and malformations incompatible with life were observed, so surgeons opted for euthanasia and necropsy. Alterations were confirmed in the genitourinary and gastrointestinal tract. The non-formation of the anus caused dilation of the distal portion of the rectum with fecal content retention, which was drained to the body of the uterus, with the presence of meconium. This amount of anatomical and clinical changes were diagnosed as congenital multiple arthrogryposis.(AU)

Este relato de caso descreve atresia anal, alteração anatômica da uretra (inserida caudalmente ao úbere), articulações espessadas e alterações na pelve em um neonato bovino da raça Holandesa. A visualização da porção final do reto não foi possível pelo acesso perineal, e laparotomia através do flanco direito foi feita para exploração abdominal e realização da colostomia. Durante o procedimento cirúrgico, foram observadas ruptura visceral e malformações incompatíveis com a vida, então os cirurgiões optaram pela eutanásia e necropsia. Alterações foram confirmadas nos tratos geniturinário e gastrointestinal. A não formação do ânus causou dilatação da porção distal do reto com retenção fecal, desviando ao corpo do útero, o qual possibilitou a entrada de mecônio nesse compartimento, além de outras alterações devido à ingestão e alteração no trânsito gastrointestinal. Essa quantidade de alterações anatômicas e clínicas foi diagnosticada como artrogripose congênita múltipla.(AU)

Societal views and animal welfare science: understanding why the modified cage may fail and other stories.

The innovations developed by scientists working on animal welfare are often not adopted in practice. In this paper, we argue that one important reason for this failure is that the solutions proposed do not adequately address the societal concerns that motivated the original research. Some solutions also fail because they do not adequately address perceived constraints within the industry. Using examples from our own recent work, we show how research methods from the social sciences can address both of these limitations. For example, those who persist in tail-docking cattle (despite an abundance of evidence showing that the practice has no benefits) often justify their position by citing concern for cow cleanliness. This result informs the nature of new extension efforts directed at farmers that continue to tail dock, suggesting that these efforts will be more effective if they focus on providing producers with methods (of proven efficacy) for keeping cows clean. Work on pain mitigation for dehorning shows that some participants reluctant to provide pain relief believe that the pain from this procedure is short lasting and has little impact on the calf. This result informs the direction of new biological research efforts to understand both the magnitude and duration of any suffering that result from this type of procedure. These, and other examples, illustrate how social science methodologies can document the shared and divergent values of different stakeholders (to ensure that proposed solutions align with mainstream values), beliefs regarding the available evidence (to help target new scientific research that meets the perceived gaps), and barriers in implementing changes (to ease adoption of ideas by addressing these barriers).

Effect of dual screws across the vertebral neurocentral synchondrosis on spinal canal development in an immature spine: a porcine model.

BACKGROUND: Questions remain as to the effect of pedicle screws on spinal canal development in young children. The purpose of this study was to determine the effects of unilateral placement of dual screws across the neurocentral synchondrosis on spinal canal development as assessed with histological analysis and measurement of the canal dimensions in an immature pig model. METHOD: Twenty-seven one-month-old pigs were assigned to two groups on the basis of the surgical approach used to place unilateral double screws that did or did not cross the neurocentral synchondrosis. In one group, sixteen pigs underwent a posterior approach from T7 to T14 and were divided into four subgroups: no screws (without screw fixation), short screws (dual pedicle screws that did not cross the neurocentral synchondrosis), long screws (dual pedicle screws that crossed the neurocentral synchondrosis), and screw removal (long dual pedicle screws that were removed at six weeks postoperatively). In the other group, eleven pigs underwent an anterior approach, with double vertebral body screws placed via thoracotomy. These animals were divided into two subgroups: short screws (dual vertebral body screws that did not cross the neurocentral synchondrosis) and long screws (dual vertebral screws that crossed the neurocentral synchondrosis). All animals were killed at seventeen weeks. The total area, width, and depth of the spinal canal were measured on axial computed tomography (CT) images. Quantitative histological analysis was performed to measure the rate of neurocentral synchondrosis closure. RESULTS: Use of unilateral double pedicle screws across the neurocentral synchondrosis through a posterior approach resulted in 97% neurocentral synchondrosis closure with a 20% decrease in the canal area and a 15% decrease in the canal depth. Use of unilateral double vertebral body screws across the neurocentral synchondrosis through an anterior approach resulted in 71% neurocentral synchondrosis closure with a 15% decrease in the canal area and an 8% decrease in the canal width. CONCLUSIONS: Unilateral double pedicle screws crossing the neurocentral synchondrosis adversely affected spinal canal growth in immature pigs. CLINICAL RELEVANCE: Pedicle screws should be used with caution in very young children, and a delay in surgical treatment until they are older should be considered.

Composite tissue allotransplantation in newborns: a swine model.

BACKGROUND: Management of congenital limb aplasia or facial malformations could be improved by composite tissue allotransplantation (CTA), a technique that has never been performed in newborns. For this, however, the induction of donor-specific tolerance would be mandatory, as long-term immunosuppression is not acceptable in this non-lifesaving procedure. Induction of tolerance has been shown to be possible in a newborn CTA rat model but has never been tested in large-animal models. Our goals were to establish a model of CTA in newborn swine to see if tolerance could be obtained without immunosuppression and to assess rejection or tolerance properties via clinical and histologic examinations. MATERIALS AND METHODS: We applied a CTA heterotopic knee swine model. We performed two series of surgical procedures: Series 1 was 20 autografts in 6-day-old (1-10) 2,544 kg (1,140-4,060 kg) piglets; Series 2 was 10 allografts without immunosuppression between outbred animals aged 7.8 d (6-10) and weighing 2,770 kg (2,200-3,550 kg). RESULTS: In Series 1, six early deaths and two cases of vascular failure were observed. In Series 2, no spontaneous deaths were observed and all piglets presented clinical and histologic rejection. CONCLUSIONS: Our findings strongly suggest that newborn immunologic status is not sufficient for the development of tolerance in large animals without immunologic intervention. Complications and animal death after transplantation correlate with age and weight. Low rates for both vascular failure and postoperative death permit the use of this model in piglets weighing over 2 kg and aged more than 6 d for research on newborn CTA.

A technique for systemic mesenchymal stem cell transplantation in newborn rat pups.

Mesenchymal stem cells (MSC) have the potential to aid tissue regeneration. Intravenous (IV) MSC administration is currently being assessed following tissue injury. However, few studies have been performed to establish a safe and effective method of IV MSC infusion for newborns. We have established a safe, nontraumatic and effective technique for systemic MSC transplantation in newborn rats. Yellow-fluorescent-protein (YFP)-labeled MSC were characterized using MSC markers and their differentiation potential was confirmed. Rat pups were delivered by C-section on gestational day 21. The umbilical vein (UV) was cannulated and used for IV injection of MSC or saline control, which was performed under ultrasonographic imaging. An additional control group consisted of UV MSC injection in adult mice. Mean operating time, success rate of cannulation and death rate were recorded. YFP-MSC quantification in multiple organs was performed. Mean operating time was 3.9 ± 1.1 min. The success of UV MSC injection was 92.8%. The immediate and 24 hr delayed death rate for rat pups was significantly lower than that of adult mice (p < .05). No pups receiving saline injection died. After locating the patent foramen ovale (PFO) of newborn pups by ultrasonographic imaging, extra pulse-waves and wave-shape changes were detected when MSC were injected. The number of YFP-MSC was 15.8 ± 4.1 cells per visual field (CPVF) in the lungs, 2.9 ± 1.2 CPVF in the heart, and 19.8 ± 5.0 CPVF in the intestines. We conclude that IV MSC infusion through the UV is a convenient, safe, and effective method for systemic MSC transplantation in prematurely delivered newborn rats.

Feasibility of orthotopic fetal liver transplantation: an experimental study.

BACKGROUND: The use of livers from nonviable fetuses is particularly attractive for its potential to solve the current limitations of organ availability for the pediatric recipient. Therefore, it is essential to study the feasibility of orthotopic fetal liver transplantation. METHOD: We measured the hepatic and extra-hepatic anatomical structures of fetal and neonatal lambs and established an orthotopic liver transplantation model of the fetal lamb. RESULTS: Mean weight of the liver of fetal lambs at 142 to 145 days gestation was 34.75 g and the mean diameter of the portal vein was 3.03 mm, the supra-hepatic vena cava was 5.88 mm, and the infra-hepatic vena cava was 4.00 mm, which matched the corresponding sizes in neonatal lambs aged up to 2 weeks. Using standard surgical procedures we completed the vascular inosculation of fetal liver. However, all the newborn lamb recipients survived less than 24 hours. CONCLUSIONS: Orthotopic transplantation of the fetal liver is anatomically and technically feasible. However, perioperative issues need to be resolved prior to clinical application.

Pain in lambs castrated at 2 days using novel smaller and tighter rubber rings without and with local anaesthetic.

Without effective pain relief, rubber ring castration of lambs is acutely painful and can also produce chronic pain. The potential of novel, smaller rubber rings to reduce this pain substantially has been investigated. Three groups of eight 2-3 day old lambs, were castrated either with conventional rubber rings (cRR), or novel smaller rubber rings without (nRR) and with local anaesthetic treatment (nRR+La). Behavioural responses and chronic lesions indicative of pain were compared. No major reductions in behavioural responses were produced by castration with nRRs compared with cRRs, but injection of local anaesthetic did reduce these responses significantly. Lambs in all groups developed chronic inflammatory lesions but behavioural evidence of chronic pain was rarely seen. After 28 days, 6/8 necrotic scrotums had been shed by nRR+La; 4/8 by nRR and 2/8 by cRR lambs. The dimensions of rubber rings on necrotic scrotums, suggest that cRRs contracted to their un-stretched size before being shed, whereas nRRs did not. It is concluded that neither of these rubber rings exerted sufficient pressure on trapped nerves to produce anaesthesia rapidly and this may be explained by the physical properties of the tissues at the neck of the scrotum which support the ring.

Impaired reality testing in an animal model of schizophrenia.

BACKGROUND: Schizophrenia is a chronic and devastating brain disorder characterized by hallucinations and delusions, symptoms reflecting impaired reality testing. Although animal models have captured negative symptoms and cognitive deficits associated with schizophrenia, none have addressed these defining, positive symptoms. METHODS: Here we tested the performance of adults given neonatal ventral hippocampal lesions (NVHL), a neurodevelopmental model of schizophrenia, in two taste aversion procedures. RESULTS: Normal and NVHL rats formed aversions to a palatable food when the food was directly paired with nausea, but only NVHL rats formed a food aversion when the cue predicting that food was paired with nausea. The failure of NVHL rats to discriminate fully real from imagined food parallels the failure of people with schizophrenia to differentiate internal thoughts and beliefs from reality. CONCLUSIONS: These results further validate the NVHL model of schizophrenia and provide a means to assess impaired reality testing in variety of animal models.