Effects of nerve growth factor on crushed sciatic nerve regeneration in rats

The effects of nerve growth factor (NGF) on crushed sciatic nerve regeneration were studied in 30 rats, with 60 bilateral nerves. The nerves were crushed at a site 6 mm distal to the sciatic notch by the standard technique and 3 mm wide crush injuries were created. Then 2.1 μl of normal saline in the control groups and an equal volume of NGF solution (containing 1 μg of NGF) in the NGF-treated groups was injected into the crush sites and followed for 12, 28, and 56 days, respectively. At the end of the observation, electrophysiological evaluation was carried out; then samples 10 mm distal to the crush site were removed and prepared for histological and morphometric studies. Evoked muscle action potential (MAP) was recorded in 50% of the NGF-treated group at 12 days but not in the control group; the difference was statistically significant (P<0.05). The motor nerve conduction velocity (MNCV) was increased in NGF-treated groups compared with control groups at 28 and 56 days (P<0.05). Morphometrically, significantly more regenerated myelinated fibers (RMFs) were seen at 12 days, and larger diameter RMFs were found at 12, 28, and 56 days in NGF-treated groups than in control groups. These results indicate that topically applied NGF stimulates nerve regeneration and promotes function recovery in crushed rat sciatic nerves. © 1995 Wiley-Liss, Inc.     

Functional and morphometric differences between the early and delayed use of phototherapy in crushed median nerves of rats

This study evaluated the functional and quantitative differences between the early and delayed use of phototherapy in crushed median nerves. After a crush injury, low-level laser therapy (GaAs) was applied transcutaneously at the injury site, 3 min daily, with a frequency of five treatments per week for 2 weeks. In the early group, the first laser treatment started immediately after surgery, and in the delayed group, after 7 days. The grasping test was used for functional evaluation of the median nerve, before, 10, and 21 days after surgery, when the rats were killed. Three segments of the median nerve were analyzed histomorphometrically by light microscopy and computer analysis. The following features were observed: myelinated fiber and axon diameters, myelin sheath area, g-ratio, density and number of myelinated fibers, and area and number of capillaries. In the proximal segment (site of crush), the nerves of animals submitted to early and delayed treatment showed myelinated fiber diameter and myelin sheath area significantly larger compared to the untreated group. In the distal segment, the myelin sheath area was significantly smaller in the untreated animals compared to the delayed group. The untreated, early, and delayed groups presented a 50, 57, and 81% degree of functional recovery, respectively, at 21 days after injury, with a significant difference between the untreated and delayed groups. The results suggest that the nerves irradiated with low-power laser exhibit myelinated fibers of greater diameter and a better recovery of function.     

Effects of photobiomodulation on glucose homeostasis and morphometric parameters in pancreatic islets of diabetic mice

Lasers in Medical Science - High-fat diets lead to accumulation of body fat that is associated with the onset of insulin resistance and type II diabetes mellitus. On the other hand,...     

Anesthetic efficacy of bupivacaine solutions in inferior alveolar nerve block

The purpose of this study was to compare the anesthetic efficacy of 2 bupivacaine solutions. Twenty-two volunteers randomly received in a crossover, double-blinded manner 2 inferior alveolar nerve blocks with 1.8 mL of racemic bupivacaine and a mixture of 75% levobupivacaine and 25% dextrobupivacaine, both 0.5% and with 1 : 200,000 epinephrine. Before and after the injection, the first mandibular premolar was evaluated every 2 minutes until no response to the maximal output (80 reading) of the pulp tester and then again every 20 minutes. Data were analyzed using the Wilcoxon paired test and the paired t test. No differences were found between the solutions for onset and duration of pulpal anesthesia and duration of soft tissue anesthesia (P > .05). It was concluded that the solutions have similar anesthetic efficacy.     

Effects of photobiomodulation and swimming on gene expression in rats with the tibialis anterior muscle injury

Lasers in Medical Science - The aim of the present study was to evaluate the effects of photobiomodulation (low-level laser therapy (LLLT)) and aquatic exercise on the expression of genes related...     

下颌骨单侧牵张成骨对下牙槽神经的影响

目的:研究下颌骨单侧牵张成骨对下牙槽神经的影响。方法:新西兰大白兔25只,24只行单侧下颌牵张,随机分为两组:一组牵张速率为0.5mm×2次/天(1mm组);另一组为0.5mm×4次/天(2mm组),间歇期均为5天,牵张长度均为10mm。在牵张完成后0周、2周、4周、8周时每组各处死3只动物,最后一只处死做对照。4%多聚甲醛灌注固定,取牵张区含下牙槽神经组织块做大体观察及组织学观察。结果:牵张区神经大体观察均可见直径变细,组织学上可见发生了不同程度的退行性变化,表现为髓鞘肿胀、层状分离和断裂、轴索数目减少,但神经外膜、束膜仍完整,随着时间延长,发生修复性变化。结论:下颌骨牵张成骨后下牙槽神经发生退行性变,但在合适的牵张速率下是可逆的,随时间延长可以完全修复。     

Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats

BACKGROUND AND OBJECTIVE: The purpose of the present study was to examine the recovery of the crushed sciatic nerve of rats after low-power laser irradiation applied to the corresponding segments of the spinal cord. STUDY DESIGN/MATERIALS AND METHODS: After a crush injury to the sciatic nerve in rats, low-power laser irradiation was applied transcutaneously to corresponding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He-Ne laser. The laser treatment was repeated 30 minutes daily for 21 consecutive days. RESULTS: The electrophysiologic activity of the injured nerves (compound muscle action potentials--CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow-up period (P < 0.001). CONCLUSION: This study suggests that low-power laser irradiation applied directly to the spinal cord can improve recovery of the corresponding insured peripheral nerve.     

Hyaluronidase increases the duration of mepivacaine in inferior alveolar nerve blocks.

PURPOSE: To evaluate the duration of the effect of mepivacaine when hyaluronidase is injected immediately prior to the end of pulpal anesthesia. PATIENTS AND METHODS: Forty bilateral, symmetrical third molar surgeries were performed in 20 healthy patients. Inferior alveolar nerve block was induced using 2.8 mL 2% mepivacaine with epinephrine. Hyaluronidase (75 turbidity-reducing units) or a placebo was injected 40 minutes after the beginning of pulpar anesthesia (randomized and double-blind trial). The duration of effect in the pulpal and gingival tissues was evaluated by response to painful electrical stimuli applied to the adjacent premolar, and by mechanical stimuli (pin prick) to the vestibular gingiva, respectively. RESULTS: In both tissues, the duration of anesthetic effect with hyaluronidase was longer (P < .01) than with the placebo. CONCLUSION: Hyaluronidase increases the duration of mepivacaine in inferior alveolar nerve blocks.     

Anesthetic efficacy of different ropivacaine concentrations for inferior alveolar nerve block

This study was conducted on 72 American Society of Anesthesiologists class 1 patients scheduled for extraction of a mandibular third molar after inferior alveolar nerve block. Each patient was randomly administered one of the following ropivacaine concentrations: 0.75%, 0.5%, 0.375%, or 0.25% (18 patients per group). Onset of block (mean +/- SD) was rapid for both 0.75% (1.4 +/- 0.4 minutes) and 0.5% (1.7 +/- 0.5 minutes) ropivacaine but significantly slower for the 0.375% (4.2 +/- 2.5 minutes) and 0.25% (10.7 +/- 3.0 minutes) concentrations. Tooth extraction was performed successfully with the 0.5% and 0.75% concentrations, and supplemental injections were not required. Second injections, however, were required with 0.375% ropivacaine. Anesthesia was unsuccessful in 13 patients given 0.25% ropivacaine even after 3 injections. The mean durations of soft tissue anesthesia were 3.3 +/- 0.3 hours and 3.0 +/- 0.3 hours for the 0.75% and 0.5% concentrations, but significantly shorter with more dilute concentrations. The duration of analgesia showed a similar pattern, with the 0.75% and 0.5% concentrations producing prolonged analgesia of 6.0 +/- 0.4 hours and 5.6 +/- 0.4 hours. These results indicate that 0.5% and 0.75% concentrations were effective for intraoral nerve blockade, with both a rapid onset and prolonged duration of pain control.     

Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks

The authors, using a crossover design, randomly administered, in a single-blind manner, inferior alveolar nerve blocks using 36 mg of lidocaine with 18 microg of epinephrine or a combination of 36 mg of lidocaine with 18 microg epinephrine plus 36 mg meperidine with 18 microg of epinephrine, at 2 separate appointments, to 52 subjects. An electric pulp tester was used to test for anesthesia, in 4-minute cycles for 60 minutes, of the molars, premolars, and central and lateral incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was continuously sustained for 60 minutes. Using the lidocaine solution, successful pulpal anesthesia ranged from 8 to 58% from the central incisor to the second molar. Using the lidocaine/meperidine solution, successful pulpal anesthesia ranged from 0 to 17%. There was a significant difference (P < .05) between the lidocaine and lidocaine/meperidine solutions for the lateral incisors through the second molars. We conclude that the addition of meperidine to a standard lidocaine solution does not increase the success of the inferior alveolar nerve block.     

Simultaneous treatment of pseudoarthrosis of mandibular body fractures and inferior alveolar nerve defects

The purpose of this paper is to present the experience with two patients with pseudoarthrosis of mandibular body fractures and unacceptable anesthesia of the lower lip and chin on the affected side. This was corrected by establishing stable fixation with locking screw mandibular plate, microsurgical repair of the inferior alveolar nerve, and filling the fracture gap with an autogeneous bone graft. The combination of these therapies resulted in satisfactory sensory improvement without complications in both patients. Received: 25 May 1999 / Accepted: 29 September 1999     

Effects of photobiomodulation therapy in the integration of skin graft in rats

Skin graft is one of the most common techniques used in plastic surgery and repair. However, there are some complications that can lead to loss of the skin graft. Thus, several features have been studied with the aim of promoting the integration of skin grafts. Among these resources, the use of laser photobiomodulation (laser PBM) has been highlighted. The present study aimed to investigate the effects of laser PBM on the viability and integration of skin grafts in rats. Twenty male Wistar rats (± 250 g) were randomly assigned into two experimental groups with 10 animals each: control group, animals submitted to skin graft and simulation of laser PBM; laser PBM group, submitted to the skin graft and submitted to laser PBM at 660 nm, 40 mW, 60 s, 2.4 J. The animals were submitted to laser photobiomodulation immediately after the surgical procedure and each 24 h. Animal euthanasia occurred on the 7th day after surgery, 24 h after the last treatment session. The histopathological analysis revealed that the laser PBM showed better adhesion of the graft when compared to the control group. Likewise, the morphometric analysis of mast cells, blood vessels, and collagen showed a statistically significant increase in the animals irradiated with the laser PBM when compared to the control group. In addition, immunohistochemical analysis demonstrated that the laser PBM showed statistically higher immunoexpression of FGF when compared to the CG. However, IL-4 immunoexpression did not show statistical difference between the experimental groups. From the results obtained in the present study, it can be suggested that laser photobiomodulation was effective in promoting the integration and viability of total skin grafts in rats.     

End-to-end versus peripheral nerve graft repair of the oculomotor nerve in rats: A comparative histological and morphometric study

A comparative study was undertaken to evaluate end-to-end versus peripheral nerve graft repair in cranial nerve reconstruction. In 14 rats, the oculomotor nerve was sharply transected in the cavernous sinus and repaired either by end-to-end coaptation (n = 7) or by interposition of a peripheral nerve graft (n = 7). The results were evaluated 16 weeks after surgery by light and transmission electron microsurgery and by morphometric analysis. The degree of neuroma formation, fibrosis, and axonal disorganisation at the repair site was the same for both groups. Histologically, both end-to-end and graft repair groups revealed various degrees of axonal regeneration with myelinated nerve fibres in the distal nerve segments. In both groups, the number of nerve fibres distal to the repair site was increased compared to proximal to the repair (P < 0.001) but myelinated axon diameter was significantly less than that of control nerves (P < 0.001). No difference existed between the two repair groups in terms of mean myelinated axonal diameter. However, the number and density of myelinated axons was statistically greater in the graft group (P < 0.05). In conclusion, despite the disadvantage of two repair sites, peripheral nerve grafting results in equal or slightly superior axonal regeneration compared to an end-to-end repair in the rodent model of intracranial oculomotor nerve reconstruction. We speculate that this may be due to the structure of the peripheral nerve graft.     

曲面断层片与下颌阻生第三磨牙拔除术中下牙槽神经损伤风险预测的初步研究

目的:通过术前下颌阻生第三磨牙曲面断层片检查,结合拔牙术中所见,探讨牙齿根尖和下颌管之间X线关系与下牙槽神经损伤风险的相关因素。方法:收集129例术前行曲面断层片检查的下颌阻生第三磨牙拔除术患者,通过曲面断层片分析牙根与下颌管的关系及术中下牙槽神经的暴露及损伤情况。术后6个月定期进行临床检查,评估患者下唇及颏部的感觉是否异常。结果:曲面断层片显示根尖或根管透射影像和根管与下颌管重叠影像的患者中,12例术中出现下颌管暴露,其中有3例术后出现暂时性感觉迟钝,需要药物治疗。结论:下颌阻生第三磨牙拨牙术前曲面断层片显示根尖或根管透射影像和根管与下颌管重叠影像,提示下牙槽神经损伤的高风险。术前仔细分析患者的曲面断层片非常重要。     

Effects of photobiomodulation therapy on neuropathic pain in rats: evaluation of nociceptive mediators and infrared thermography

Lasers in Medical Science - Nerve injury induces release of peptides and upregulation of receptors such as substance P and transient receptor potential receptor V1 (TRPV1), which contribute to the...     

Injection pain of the inferior alveolar nerve block in patients with irreversible pulpitis.

OBJECTIVE: The purpose of this retrospective analysis was to determine the pain associated with needle insertion, placement, and solution deposition for the conventional inferior alveolar nerve (IAN) block in patients with irreversible pulpitis. STUDY DESIGN: One hundred two emergency patients with irreversible pulpitis received IAN block injections using 2% lidocaine with 1:100,000 epinephrine. The patients recorded pain of the 3 injection stages on a Heft-Parker visual analog scale (VAS). RESULTS: Moderate-to-severe pain may occur 57% to 89% of the time with the IAN block. Needle placement was significantly more painful than needle insertion for men and significantly more painful than either insertion or deposition for women (P < .03). There was no statistical difference between the pain for men or women with respect to needle insertion, placement, or deposition pain (P > .05). Deposition of 0.2 to 0.4 mL anesthetic during placement did not significantly reduce placement pain for either gender (P = .753). CONCLUSION: In conclusion, 57% to 89% of patients presenting with irreversible pulpitis have the potential for moderate to severe pain with the IAN block.     

大鼠脊髓损伤后GDNFmRNA表达变化及意义

目的　探讨 GDNFm RNA在大鼠脊髓损伤后表达变化及其意义。方法　改良 Allen’s脊髓撞击 (10 g× 7.5 cm)致伤大鼠 T1 段脊髓 ,以 β- Actin为内参照物 ,应用半定量 RT- PCR方法 ,观察大鼠脊髓损伤前及损伤后不同时间 GDNFm RNA表达变化。结果　 GDNFm RNA在正常成年大鼠脊髓微量表达 ,脊髓损伤后 2 4h表达增加 5倍 ,72 h增加 2 0倍 ,7d增加 4倍 ,10 d仍高于正常水平。结论　脊髓损伤后早期 GDNFm RNA表达增加 ,是神经元自我保护作用的一种表现 ;损伤神经元修复需要大量 GDNF,应用 GDNF治疗脊髓损伤时应早期用药     

Anesthetic efficacy of a combination of hyaluronidase and lidocaine with epinephrine in inferior alveolar nerve blocks

The purpose of this prospective, randomized, double-blind study was to determine the anesthetic efficacy of a buffered lidocaine with epinephrine solution compared to a combination buffered lidocaine with epinephrine plus hyaluronidase solution in inferior alveolar nerve blocks. Thirty subjects randomly received an inferior alveolar nerve block using 1 of the 2 solutions at 2 separate appointments using a repeated-measures design. Mandibular anterior and posterior teeth were blindly pulp tested at 4-minute cycles for 60 minutes postinjection. No response from the subject to the maximum output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive readings of 80 were obtained. A postoperative survey was used to measure pain and trismus. The results demonstrated 100% of the subjects had profound lip numbness with both solutions for inferior alveolar nerve blocks. The anesthetic success rates for individual teeth ranged from 20 to 80%. There were no significant differences (P > .05) between the 2 solutions. However, the combination lidocaine/hyaluronidase solution resulted in a significant increase in postoperative pain and trismus. It was concluded that adding hyaluronidase to a buffered lidocaine solution with epinephrine did not statistically increase the incidence of pulpal anesthesia in inferior alveolar nerve blocks and, because of its potential tissue damaging effect, it should not be added to local anesthetic solutions for inferior alveolar nerve blocks.     

Effect of nerve growth factor and Schwann cells on axon regeneration of distracted inferior alveolar nerve following mandibular lengthening

To study the effect of nerve growth factor(NGF) and Schwann cells on axon regeneration of theinferior alveolar nerve following mandibular lengtheningwith distraction osteogenesis.