Histologic tissue response to furcation perforation repair using mineral trioxide aggregate or dental pulp stem cells loaded onto treated dentin matrix or tricalcium phosphate.

OBJECTIVES: The aim of this study is to compare the effect of treated dentine matrix (TDM) and tricalcium phosphate (TCP) scaffolds on odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs) in furcation perforations created in the pulp chamber floor of premolar teeth in dogs. MATERIAL AND METHODS: DPSCs were isolated and cultured from the dental pulp of the maxillary left second and third premolars of dogs. The DPSCs were loaded on TCP (SC+TCP) and TDM (SC+TDM) scaffolds and inserted into intentionally perforated pulp chamber floors of premolars in dogs; six teeth were used for each group. Three more groups of six specimens were created, and mineral trioxide aggregate (MTA), TDM, and TCP were inserted into the perforations to act as controls. An intact premolar and no treatment in the perforation site were used as positive and negative controls respectively. After 3 months, the animals were sacrificed and the type of inflammation, presence of dentine, continuation and type of cementum, type of connective tissue, and presence of foreign body reaction were evaluated, and significant differences were between groups determined using the Fisher's exact test. The evaluation of the amount of inflammation and the percentage of new bone formation was evaluated using the Mann-Whitney U test. RESULTS: The negative control group was associated with severe inflammation and granulation tissue formation. In the positive control group, intact periodontal tissues and no inflammation were observed. Dentine bridge formation was not seen in specimens of any group. The specimens in the SC+TDM group were associated with significantly more bone formation than other groups (P < 0.001). The amount of inflammation was less than 10 % in specimens of all groups with the exception of three specimens in the TCP group that were categorized as 10-30 %. Chronic inflammation without foreign body reactions was the major pattern of inflammation in groups. Formation of cementum with a cellular and continuous appearance was seen in all specimens. CONCLUSIONS: SC+TDM was associated with significantly more bone formation when used to repair uninfected furcation perforations in the premolar teeth of dogs. CLINICAL RELEVANCE: Application of TDM as a biological scaffold in combination with DPSCs may offer an advantage during the repair of root perforation defects.

Effect of local irradiation with 630 and 860 nm low-level lasers on tympanic membrane perforation repair in guinea pigs.

OBJECTIVE: In this study, we evaluated the effect of low-level lasers on the healing of tympanic membrane perforation, one of the most common otological pathologies. METHODS AND MATERIALS: Twenty-four guinea pigs were randomly assigned to either the experimental or control group. One day after the induction of a 2 mm diameter, centred myringotomy in all animals, the tympanic membranes in the experimental group were irradiated with 630 and 860 nm lasers for 10 days. Two weeks later, histological changes in the membranes were evaluated. RESULTS: Tympanic membrane thickening and inflammatory cell infiltration in the tympanic membranes and surrounding tissues were significantly less in the experimental group (p < 0.001). The distance from the external auditory canal wall to the malleus tip did not differ significantly between the two groups (p = 0.42). CONCLUSION: The results show that the combined application of 630 and 860 nm lasers had a significant effect on the healing of tympanic membrane perforation, and on the prevention of thick fibrotic or atelectatic neomembrane formation.

Radiological evaluation of the effect of biphasic calcium phosphate scaffold (HA+TCP) with 5, 10 and 20 percentage of porosity on healing of segmental bone defect in rabbit radius.

The objective of this study is to radiologically evaluate the effects of biphasic calcium phosphate scaffold with 5, 10 and 20 percentage of porosity on cortical bone repair in rabbits. In this study, 28 male white rabbits were examined. Rabbits were divided into four groups. After induction of general anesthesia, a segmental bone defect of 10 mm in length was created in the middle of the right radius shaft. In group A, the defect was stabilized with miniplate and 2 screws and left untreated. In groups B, C and D tricalcium phosphate scaffold mixed with hydroxyapatite (TCP+HA) with 5%, 10% and 20% porosity was used to fi ll the bone defect. Bone regeneration and HA+TCP scaffold resorption were assessed by X-ray at 1, 2 and 3 months after the surgery. In group A, 3 months after surgery, periosteal callus was not found but intercortical callus was observed. In groups B and C, 3 months after surgery medullary bridging callus and intercortical callus were found, periosteal callus was not found, TCP+HA scaffold were observed. In group D, 2 months after the surgery, medullary bridging callus and intercortical callus were found, 3 months later, periosteal callus was not found, most of scaffold had disappeared and were unclear and partial bone formation was recognized. Differences observed in radiological findings were significant between group A and groups B, C, D. Differences between groups B and C were not significant, but between group D and groups B and C were significant. The results of this study showed that TCP+HA scaffold is an osteoconductive and osteoinductive biomaterial. Scaffold of TCP+HA can increase the amount of newly formed bone and more rapid regeneration of bone defects. These results suggest TCP+HA scaffold may considerably be used in the treatment of cortical bone defect and other orthopaedic defects PCL (Tab. 2, Fig. 4, Ref. 20).

A comparison between the efficacy of Bio-Oss, hydroxyapatite tricalcium phosphate and combination of mesenchymal stem cells in inducing bone regeneration.

BACKGROUND: Recently, tissue engineering has been introduced as a regenerative treatment for bone defects. There is some evidence showing bone regeneration from mesenchymal stem cells (MSC) loaded on hydroxyapatite ß-tricalcium phosphate (HA/TCP) as a scaffold in large defects. This study aimed to compare the quality and quantity of regenerated bone using Bio-Oss, HA/TCP and MSC loaded HA/TCP scaffolds. METHODS: Mesenchymal stem cells were aspirated from iliac crest bone marrow after extracting the first, second and third premolars and the first molar in five mature hybrid dogs. The cells were cultured and their osteogenic differentiation potential was evaluated after the third cell passage using Alizarin red staining in experimental conditions. The HA/TCP scaffold (3 × 3 × 3 mm) was loaded with undifferentiated mesenchymal stem cells. Bilateral bone defects were then prepared in the jaws using trephine burs. The defects were randomly filled with HA/TCP, Bio-Oss, or HA/TCP + MSCs. One defect served as a control and was left as an empty cavity. All defects except the control defect were covered with an absorbable membrane. Histological and histomorphometric evaluations were conducted after 6 weeks and data were subjected to analysis of variance (ANOVA) (p < 0.05). RESULTS: The empty cavity demonstrated more bone formation (60.80%) than the HA/TCP (44.93%) and Bio-Oss (40.60%) (p < 0.05) groups. However, the difference from the HA/TCP + MSCs group was not significant (46.38%) (p > 0.05). CONCLUSION: An MSC-loaded HA/TCP scaffold is a more effective alternative than Bio-OSS or HA/TCP in inducing bone regeneration.

Transplantation of a combination of autologous neural differentiated and undifferentiated mesenchymal stem cells into injured spinal cord of rats.

STUDY DESIGN: The use of stem cells for functional recovery after spinal cord injury. OBJECTIVE: The aim of this study was to evaluate the effects of a combination of autologous undifferentiated and neural-induced bone marrow mesenchymal stem cells (MSCs) on behavioral improvement in rats after inducing spinal cord injury and comparing with transplantation of undifferentiated and neural-induced MSCs alone. SETTING: The study was conducted at the department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. METHODS: The spinal cord was injured by contusion using a Fogarty embolectomy catheter at the T8-T9 level of the spinal cord, and autologous MSCs were transplanted into the center of the developing lesion cavity, 3 mm cranial and 3 mm caudal to the cavity, at 7 days after induction of spinal cord compression injury. RESULTS: At 5 weeks after transplantation, the presence of transplanted cells was detected in the spinal cord parenchyma using immunohistochemistry analysis. In all treatment groups (differentiated, undifferentiated and mix), there was less cavitation than lesion sites in the control group. The Basso-Beattie-Bresnahan (BBB) score was significantly higher in rats transplanted with a combination of cells and in rats transplanted with neural-induced MSCs alone than in undifferentiated and control rats. CONCLUSION: Pre-differentiation of MSCs to neuron-like cells has a very important role in achieving the best results for functional improvement.

Formation of interconnected macropores in apatitic calcium phosphate bone cement with the use of an effervescent additive.

Calcium phosphate cements (CPCs) can be considered as good candidate for bone tissue engineering because they can be resorbed and take part in the bone remodeling process. Several efforts have been made into improve the resorption rate of the calcium phosphate cement by introducing macropores to the cement matrix. In this investigation a simple and effective method has been presented based on the addition of various amounts of an effervescent agent to the calcium phosphate cement components. The effervescent agent was a mixture of sodium hydrogen carbonate, NaHCO(3) (that was added to the powder phase), and citric acid monohydrate, C(6)H(8)O(7).H(2)O (that was dissolved in the liquid phase). The obtained macroporous samples were characterized by Fourier transform infrared spectrometer, X-ray diffraction, and scanning electron microscopy techniques at 4 h after setting and 3 days after soaking in a special simulated body fluid solution named Hank's balanced salt solution. Mercury intrusion porosimetry was also employed for characterizing the pore volume and pore size distribution in the cement structure. Results showed that the rate of conversion of staring reactant to the apatite phase and the apatite chemistry were significantly changed by using the additive in the cement components. Also both the pore volume and pore size were changed by varying both the amount of effervescent additive and the powder to liquid ratio.

Evaluation of halothane as an anaesthetic in camels (Camelus dromedarius).

Halothane as an anaesthetic was evaluated in 12 adult camels, thiopentone being used as an induction agent. In six camels, clinical signs and haematological and blood biochemical changes were investigated while in other six haemodynamic, acid base and blood gas changes were monitored. The dose of thiopentone required to ensure intubation for halothane anaesthesia was 7.25 +/- 0.33 mg/kg. A modified technique of tracheal intubation was found to be safe and quick. During halothane administration all anaesthetic effects were predictable. Complete recovery occurred in 39.5 +/- 9.8 min after discontinuation of halothane administration. Halothane moderated the thiopentone-induced tachycardia. The mean arterial pressure decreased significantly. There was an increase in the arterial carbon dioxide and venous oxygen tension during halothane anaesthesia and development of hypoxaemia after its discontinuation. The alanine aminotransferase values increased during recovery, while plasma sodium, potassium and calcium decreased. Halothane appears to be safe for camels. However, to avoid hypoxaemia in the immediate post-anaesthetic period, oxygen administration should be continued.

Evaluation of triflupromazine as a sedative in camels (Camelus dromedarius).

Effects of administration of triflupromazine were evaluated in 11 adult domesticated camels (Camelus dromedarius) weighing 403 +/- 29.5 kg (Mean +/- SE). Six camels were used to evaluate sedative properties of the drug and its effects on haematological and blood biochemical parameters. In the remaining 5 camels, effects on haemodynamics, acid base status and blood gases were studied. In all the animals triflupromazine was administered intramuscularly in the gluteal region at the rate of 2 mg/kg. Camels voluntarily sat down 48.9 +/- 5.4 min after administration of the drug but stood up again if disturbed. Drowsiness, drooping of lower lip and salivation were evident. The animals stood on their own and started walking with ataxia after 159 +/- 7 min and recovered completely from the effect of drug within 259 +/- 23 min. The drug caused a significant tachycardia and a moderate hypotension. The decrease in central venous pressure was also significant. Rectal temperature, respiratory rate, acid base status, blood gases, haemoglobin concentration, packed cell volume, total erythrocyte count, total leucocyte count, differential leukocyte count, blood urea nitrogen, plasma alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, blood glucose and plasma concentrations of sodium, potassium, chloride and inorganic phosphate were not significantly affected by triflupromazine.

Studies on intravenous regional analgesia of the hind limb in the bovine.

Twenty-five buffalo calves (age: 14 +/- 1.9 months; body weight: 102 +/- 9.4 kg) were subjected to intravenous regional analgesia (IRA) of the hind limb with 2% lignocaine HCl (4 mg/kg b.w.), infused through the dorsal digital vein. In control animals 15 ml of normal saline was infused. The effect of tourniquet release after 35 (8 calves) and 65 min (7 calves) on EEG, ECG, arterial and venous pressures, blood gases and pH, respiration and temperature were studied. A detectable concentration of lignocaine occurred before the release of tourniquet. The lignocaine concentration recorded in the systemic circulation did not produce any significant nervous or cardiovascular changes before or after release of tourniquet. Transient EEG and ECG changes were seen in six (tourniquet release after 35 min) and three (tourniquet release after 65 min) IRA animals, respectively. No significant changes were seen in heart rate, respiratory rate and rectal temperature, systolic, diastolic, mean arterial and central venous pressures. Arterial blood pH, PCO2 and HCO3- concentration showed no significant differences. Animals receiving IRA did not show hypoxaemia typical to postural changes.

Sedative effect of detomidine in infant calves.

Detomidine administered intramuscularly at a dose of 10, 20 or 40 micrograms/kg body mass was evaluated for its sedative effects in 15 unfasted infant calves (age: 15-20 days; body mass: 18-33 kg). The drug produced dose-dependent sedation. At a dose of 10 micrograms/kg detomidine produced effective sedation for 30 to 45 min without any observable analgesia. At doses of 20 or 40 micrograms/kg it caused deep sedation, sternal recumbency, and moderate analgesia of the trunk. Hyperglycaemia was recorded at all dose levels. The changes in respiratory rate, rectal temperature, haemoglobin, packed cell volume, total erythrocyte count and plasma concentration of total protein were not significant.

Evaluation of detomidine as a sedative in goats.

Intramuscular (i.m.) and intravenous (i.v.) administration of detomidine at doses of 10, 20 and 40 micrograms/kg body mass was evaluated for its sedative and analgesic properties in 15 goats (Capra hircus). The drug produced dose- and route-dependent sedation. The 10 micrograms/kg dose was effective only when administered i.v. There was no observable analgesia at this dose. Higher doses produced effective sedation and moderate analgesia of the body with either route of administration. Severe ataxia and sternal recumbency were seen in all the animals after the dose of 40 micrograms/kg. Other effects of detomidine in these goats included mild to moderate salivation, depressed respiratory rate, decreased rectal temperature, bradycardia and hyperglycaemia. Plasma concentrations of total protein, sodium, potassium and chloride were not affected.