The Discovery of a Bone in the Anterior Fontanelle of the Skull of the Sheep (Ovis aries) / Descubrimiento de un Hueso en la Fontanela Anterior del Cráneo de la Oveja (Ovis aries)

SUMMARY: A comparative study of the skull morphology was conducted using 270 prenatal and 750 postnatal skull samples from three breeds of sheep in Nigeria namely, Balami, Uda and Yankasa. A unique bone peculiar to the Yankasa breeds of sheep was found consistently at the centre of the anterior fontanelle in the young (day-old to 1 year). At two years of age and above, the bone was fused and disappeared completely. This brings the total numbers of the neurocranium bones of the skull in the Yankasa breeds to 8, as against the 7 bones documented in the ovine species. Due to the fact that this bone has not been described in the literature, we venture to name it the anterio-fontanelle bone (of Atabo).

Se realizó un estudio comparativo de la morfología del cráneo utilizando 270 muestras de cráneos prenatales y 750 postnatales de tres razas de ovejas en Nigeria, Balami, Uda y Yankasa. Un hueso único peculiar de las razas de ovejas Yankasa se encontró consistentemente en el centro de la fontanela anterior en las crías (de un día a 1 año). A los dos años de edad o más, el hueso se fusionó y desapareció por completo. Esto eleva el número total de huesos del neurocráneo en el cráneo en las razas Yankasa a 8, frente a los 7 huesos documentados en la especie ovina. Debido a que este hueso no ha sido descrito en la literatura, nos aventuramos a denominarlo hueso antero-fontanela (de Atabo).

Histopathological and radiographical evaluation of caprine demineralized bone matrix in a critical ulnar defect in a rabbit model.

BACKGROUND: Caprine species satisfy the conditions of an ideal donor animal when compared to bovine species that has been extensively studied and commercialized for bone xenograft. Histopathological and radiological evaluations of caprine demineralized bone matrix (CDBM) were therefore carried out for fracture healing properties for its possible use in bone grafting procedures. MATERIALS AND METHODS: Twenty-four rabbits were used for this study and were divided randomly into three groups of eight (n = 8) rabbits each. Critical bone defect was created on the ulnar diaphysis under xylazine-ketamine anaesthesia for autogenous bone graft (ABG) group, CDBM group and the last group was left unfilled as negative control (NC). Immediate post-grafting radiograph was taken and repeated on days 14, 28, 42 and 56 to monitor the evidence of radiographic healing. The animals were euthanized on day 56 and defect sites were harvested for histopathology. RESULTS: There was a progressive evidence of radiographic healing and bone formation in all the groups with significance difference (P = 0.0064). When compared with ABG, NC differ significantly (P < 0.0001) whereas the CDBM did not differ significantly (P = 0.6765). The histopathology sections of ABG and CDBM showed normal bone tissue while the NC section was predominated by fibrous connective tissue. There was therefore an overall significant difference (P = 0.0001) in which CDBM did not differ from ABG (P = 0.2946) while NC did (P = 0.0005). CONCLUSION: The ABG and CDBM groups showed a similar healing effect in the critical bone defect. Therefore, CDBM could be used as an effective alternative to ABG in orthopaedics to circumvent the limitations and complications associated with it. LEVEL OF EVIDENCE: Not applicable.

Roles of Sodium Hydrogen Exchanger (NHE1) and Anion Exchanger (AE2) across Chondrocytes Plasma Membrane during Longitudinal Bone Growth.

Mammalian long bone growth occurs through endochondral ossification, majorly regulated by the controlled enlargement of chondrocytes at the growth plate (GP). This study aimed to investigate the roles of Na+/H+ (sodium hydrogen exchanger (NHE1)) and HCO3− (anion exchanger [AE2]) during longitudinal bone growth in mammals. Bones from P10 SpragueDawley rat pups were cultured exvivo in the presence or absence of NHE1 and AE2 inhibitors to determine their effect on long bone growth. Gross morphometry, histomorphometry, and immunohistochemistry were used to assess the bone growth. The results revealed that the culture of the bones in the presence of NHE1 and AE2 inhibitors reduces bone growth significantly (p < 0.05) by approximately 11%. The inhibitor significantly (p < 0.05) reduces bone growth velocity and the length of the hypertrophic chondrocyte zone without any effect on the total GP length. The total GP chondrocyte density was significantly (p < 0.05) reduced, but hypertrophic chondrocyte densities remained constant. NHE1 fluorescence signaling across the GP length was higher than AE2, and their localization was significantly (p < 0.05) inhibited at the hypertrophic chondrocytes zone. The GP lengthening was majorly driven by an increase in the overall GP chondrocyte and hypertrophic chondrocyte densities apart from the regulatory volume phenomenon. This may suggest that NHE1 and AE2 could have a regulatory role in long bone growth.

Hematological Changes after Caprine Demineralized Bone Matrix Implantation in Ulnar Critical Defect of Rabbit Model.

Objective Several animal models have been used in fracture healing and bone graft studies, but hematological responses are seldom reported. Therefore, the present study reported the hematological changes observed in rabbits that underwent xenografting of caprine demineralized bone matrix (CDBM). Method Twenty-four (24) male rabbits (2.5 ± 0.5kg) were acquired for the purpose of this study and were randomly assigned to three groups: autologous bone graft (ABG), unfilled (NC), and caprine demineralized bone matrix (CDBM). Blood samples were collected through cardiac puncture under xylazine-ketamine anesthesia on day 0 (baseline), and on days 28 and 56 postsurgery and were analyzed manually within 2 hours of collection. Statistical analysis was performed using a two-way analysis of variance (ANOVA) with repeated measures, and a p -value < 0.05 was considered significant. Result There was an overall significant difference in the values of total white blood cell count ( p = 0.0043), neutrophil count ( p < 0.0001), monocyte count ( p = 0.0184), red blood cell count ( p = 0.003), hemoglobin concentration ( p < 0.0001) and packed cell volume ( p < 0.0001) across the days and the treatment groups. There was, however, no overall significant difference in lymphocyte count ( p = 0.4923), basophil count ( p = 0.4183), and eosinophil count (0.4806) within days. Conclusion Response to CDBM grafting in rabbits could, therefore, be said to be characterized by marked leukocytosis with neutrophilia, lymphocytosis, and monocytosis by day 28 of postgrafting. This could form the basis with which hematology can be used to monitor body response of bone graft animal models.

Hematological Changes after Caprine Demineralized Bone Matrix Implantation in Ulnar Critical Defect of Rabbit Model / Alterações hematológicas após implante de matriz óssea desmineralizada caprina em modelo de defeito ulnar crítico em coelhos

Abstract Objective Several animal models have been used in fracture healing and bone graft studies, but hematological responses are seldom reported. Therefore, the present study reported the hematological changes observed in rabbits that underwent xenografting of caprine demineralized bone matrix (CDBM). Method Twenty-four (24) male rabbits (2.5 0.5kg) were acquired for the purpose of this study and were randomly assigned to three groups: autologous bone graft (ABG), unfilled (NC), and caprine demineralized bone matrix (CDBM). Blood samples were collected through cardiac puncture under xylazine-ketamine anesthesia on day 0 (baseline), and on days 28 and 56 postsurgery and were analyzed manually within 2hours of collection. Statistical analysis was performed using a two-way analysis of variance (ANOVA) with repeated measures, and a p-value< 0.05 was considered significant. Result There was an overall significant difference in the values of total white blood cell count (p» 0.0043), neutrophil count (p< 0.0001), monocyte count (p» 0.0184), red blood cell count (p» 0.003), hemoglobin concentration (p< 0.0001) and packed cell volume (p< 0.0001) across the days and the treatment groups. There was, however, no overall significant difference in lymphocyte count (p» 0.4923), basophil count (p» 0.4183), and eosinophil count (0.4806) within days. Conclusion Response to CDBM grafting in rabbits could, therefore, be said to be characterized by marked leukocytosis with neutrophilia, lymphocytosis, and monocytosis by day 28 of postgrafting. This could form the basis with which hematology can be used to monitor body response of bone graft animal models.

Resumo Objetivo Diversos modelos animais têm sido usados em estudos sobre enxertos ósseos e o tratamento de fraturas, mas as respostas hematológicas são raramente relatadas. Este estudo descreveu as alterações hematológicas observadas em coelhos submetidos a xenoenxertos de matriz óssea desmineralizada caprina (MODC). Métodos Vinte e quatro (24) coelhos machos (2,5 0,5 kg) foram adquiridos para este estudo e divididos aleatoriamente em três grupos: enxerto ósseo autólogo (EOA); controle negativo sem preenchimento (SP) e matriz óssea desmineralizada caprina (MODC). Amostras de sangue foram coletadas por punção cardíaca sob anestesia com xilazina-quetamina no dia 0 (para estabelecimento dos valores basais) e aos dias 28 e 56 após a cirurgia; essas amostras foram submetidas à análise manual em até 2 horas após a coleta. A análise estatística foi composta por análise de variância (ANOVA) de dois fatores com medidas repetidas, e o valor de p< 0,05 foi considerado significativo. Resultados Houve uma diferença geral significativa nos números de leucócitos totais (p» 0,0043), neutrófilos (p< 0,0001), monócitos (p» 0,0184) e hemácias (p» 0,003), na concentração de hemoglobina (p< 0,0001) e no hematócrito (p< 0,0001) ao longo dos dias e entre os grupos de tratamento. No entanto, não houve diferença global significativa no número de linfócitos (p» 0,4923), basófilos (p» 0,4183) e eosinófilos (p» 0,4806) entre os dias. Conclusão A resposta ao enxerto de MODC em coelhos é, portanto, caracterizada por leucocitose intensa com neutrofilia, linfocitose e monocitose no 28° dia após o procedimento. Esses dados podem basear a utilização da hematologia no monitoramento da resposta corporal em modelos animais de enxerto ósseo.

Veterinary acutherapy in management of musculoskeletal disorders: An eye-opener to the developing countries' veterinarians.

Traditional Chinese medicine practitioners believed that the maintenance of the health status of any individual or animal is by the harmonious flow of Chi (life force) along a pathway known as the meridian. Interruption or blockage of Chi brings about disorders, pain, and diseases. Acutherapy, therefore, aims at correcting the interruption or blockage of the harmonious flow of Chi along the meridian to restore the healthy condition of the body system. This correction could be accomplished by either acupuncture or acupressure, and are both collectively referred to as acutherapy. This form of therapy has been used in both humans and animals for several decades. It is, however, just gaining popularity in the treatment of humans and is still not yet in practice among veterinarians for animal patients in most developing countries like Nigeria. This review, therefore, is aimed at exposing veterinarians from the developing countries to the general application of acutherapy with emphasis on the musculoskeletal system and associated pain where it is most applied. It is highly recommended that the universities, where Veterinary Medicine is studied in developing countries, should endeavor to train their veterinary surgeons in this area and see to how acutherapy can be included in the curriculum.

Postnatal ex vivo rat model for longitudinal bone growth investigations.

BACKGROUND: Chondrocytes in the growth plate (GP) undergo increases in volume during different cascades of cell differentiation during longitudinal bone growth. The volume increase is reported to be the most significant variable in understanding the mechanism of long bone growth. METHODS: Forty-five postnatal Sprague-Dawley rat pups, 7-15 days old were divided into nine age groups (P7-P15). Five pups were allocated to each group. The rats were sacrificed and tibia and metatarsal bones were harvested. Bone lengths were measured after 0, 24, 48, and 72 hours of ex vivo incubation. Histology of bones was carried out, and GP lengths and chondrocyte densities were determined. RESULTS: There were significant differences in bone length among the age groups after 0 and 72 hours of incubation. Histological sectioning was possible in metatarsal bone from all age groups, and in tibia from 7- to 13-day-old rats. No significant differences in tibia and metatarsal GP lengths were seen among different age groups at 0 and 72 hours of incubation. Significant differences in chondrocyte densities along the epiphyseal GP of the bones between 0 and 72 hours of incubation were observed in most of the age groups. CONCLUSION: Ex vivo growth of tibia and metatarsal bones of rats aged 7-15 days old is possible, with percentage growth rates of 23.87 ± 0.80% and 40.38 ± 0.95% measured in tibia and metatarsal bone, respectively. Histological sectioning of bones was carried out without the need for decalcification in P7-P13 tibia and P7-P15 metatarsal bone. Increases in chondrocyte density along the GP influence overall bone elongation.

Pre-emptive multimodal analgesia with tramadol and ketamine-lidocaine infusion for suppression of central sensitization in a dog model of ovariohysterectomy.

OBJECTIVES: The effects of pre-emptive infusion of ketamine-lidocaine with tramadol on the suppression of central sensitization were investigated in a dog ovariohysterectomy model. PATIENTS AND METHODS: Twelve dogs were randomly assigned to two groups: ketamine-lidocaine-tramadol (KLT) and tramadol (T) groups. Both groups received intravenous tramadol 4 mg/kg body weight as premedication. Immediately after induction, the KLT group received ketamine and lidocaine at 0.5 and 2 mg/kg loading dose, followed by continuous rate infusion of 50 and 100 µg/kg/min, respectively, for 2 hours. Dogs in T group received saline bolus and continuous rate infusion at equi-volume. Intraoperatively, hemodynamic responses to surgical stimulation were recorded, whereas postoperative pain was evaluated using an algometer and short form of the Glasgow composite measure pain scale. RESULTS: Intraoperatively, hemodynamic responses to surgical stimulation were obtunded to a greater degree in KLT compared to T group. Postoperatively, the pain scores increased only for the first hour in KLT group, compared to 12 hours in T group. Mechanical thresholds at the abdomen decreased postoperatively between 12 and 60 hours in KLT group versus the entire 72 hours in T group. Thresholds at tibia and radius in both groups increased in the immediate 1 hour postoperatively, but decreased thereafter. Significant decrement of thresholds from baseline were detected in the tibia at 24, 42, and 60 hours in KLT group compared to 24-72 hours in T group, and in the radius between 36 and 48 hours in T group, but none in KLT group. CONCLUSION: Addition of pre-emptive ketamine-lidocaine infusion to single intravenous dose of tramadol enhanced attenuation of central sensitization and improved intra- and postoperative analgesia.

Histological changes of immediate skin expansion of the distal limb of rats.

AIM: Tissue expansion is an applicable technique to reconstruct many surgical defects. The aim of this research was to evaluate the histological changes caused by immediate skin tissue expansion in rats as an animal model. MATERIALS AND METHODS: Immediate skin tissue expansion in 18 adult female rats was performed using three different sizes (small, medium, and big) of polymethylmethacrylate tissue expanders at the dorsal surface of the metatarsal area of the right limb. The contralateral limb was served as the control. The tissue expanders were surgically implanted and kept for 15 days. RESULTS: The immediate skin expansion resulted in histological changes such as the increased thickness of the epidermal layer, the reduction of the dermal layer, an elevated number of fibroblast as well as increased vascularity. Furthermore, skin adnexal structures such as hair follicles and sebaceous glands were farther apart. CONCLUSION: The rat skin was able to rapidly adjust and compensate against a specific range of immediate mechanical expansion. The histological changes suggest that the tissues were prepared to withstand the increased external forces, in addition to create possibly additional skin in a relatively short-term period.

Serum concentration of ketamine and antinociceptive effects of ketamine and ketamine-lidocaine infusions in conscious dogs.

BACKGROUND: Central sensitization is a potential severe consequence of invasive surgical procedures. It results in postoperative and potentially chronic pain enhancement. It results in postoperative pain enhancement; clinically manifested as hyperalgesia and allodynia. N-methyl-D-aspartate (NMDA) receptor plays a crucial role in the mechanism of central sensitisation. Ketamine is most commonly used NMDA-antagonist in human and veterinary practice. However, the antinociceptive serum concentration of ketamine is not yet properly established in dogs. Six dogs were used in a crossover design, with one week washout period. Treatments consisted of: 1) 0.5 mg/kg ketamine followed by continuous rate infusion (CRI) of 30 µg/kg/min; 2) 0.5 mg/kg ketamine followed by CRI of 30 µg/kg/min and lidocaine (2 mg/kg followed by CRI of 100 µg/kg/min); and 3) 0.5 mg/kg ketamine followed by CRI of 50 µg/kg/min. The infusion was administered up to 120 min. Nociceptive thresholds and ketamine serum concentrations were measured before drug administration, and at 5, 10, 20, 40, 60, 90, 120, 140 and 160 min after the start of infusion. RESULTS: Maximum concentration recorded was 435.34 ± 26.18 ng/mL, 582.34 ± 227.46 ng/mL and 733.77 ± 133.6 ng/mL for K30, KL30 and K50, respectively. The concentration at 120 min was 250.87 ± 39.87, 221.73 ± 91.03 and 343.67 ± 63.21 ng/mL at 120 min in K30, KL30 and K50, respectively. All the three infusion regimes maintained serum concentrations above 200 ng/mL. The thresholds returned towards baseline values within 20 min, after cessation of infusion. CONCLUSION: Serum concentration to produce mechanical antinociceptive effects in dogs is between 100 and 200 ng/mL. All the three infusion regimes in this study provided antinociceptive effects throughout the infusions. In this study, we found that the serum concentration of ketamine to produce mechanical antinociceptive effects in dogs is above 200 ng/mL. All three infusion regimes provided antinociceptive effects throughout the infusions without causing harmful effects. Further studies are recommended in a clinical setting.

Validation of a modified algometer to measure mechanical nociceptive thresholds in awake dogs.

This study was conducted to validate the use of a modified algometer device to measure mechanical nociceptive thresholds in six dogs. Dogs were administered morphine intravenously (IV) at 1 mg/kg or saline at equivolume in a crossover design with one-week washout period. Mechanical nociceptive thresholds were determined before, after the administration of treatments at 5 minutes, and hourly for 8 hours. Thresholds were recorded at the carpal pad, metacarpal foot pad, tibia, femur, and abdomen. Heart rates, body temperature, and respiration were recorded at similar time points. Thresholds increased significantly (P < 0.05) from baseline values for up to 3 hours at tibia and abdomen, 4 hours at metacarpal pad, and 5 hours at the carpal pad and femur. Hypothermia, bradycardia, and change in respiration were observed in all dogs after morphine injection. Saline did not alter any threshold levels during the eight-hour study period, indicating no evidence of tolerance, learned avoidance, or local hyperaesthesia. The device and methods of testing were well tolerated by all the dogs. Results suggest that the modified algometer and method of application are useful to measure nociceptive mechanical thresholds in awake dogs.