Bone regeneration of demineralized dentin matrix with platelet-rich fibrin and recombinant human bone morphogenetic protein-2 on the bone defects in rabbit calvaria.

BACKGROUND: This study was to evaluate the bone formation ability of demineralized dentin matrix (DDM) combined with platelet-rich fibrinogen (PRF) and DDM combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) to improve the osteoinductive ability of DDM. METHODS: After four bone defects with a diameter of 8mm were created in the calvarium of each rabbit, DDM was grafted into the first defect (experimental groups 1), a combination of DDM and PRF was grafted into the second defect (experimental groups 2), and DDM with absorbed rhBMP-2 was grafted into the third defect (experimental groups 3). The fourth defect was used as the control group. Twelve healthy male rabbits (New Zealand, white rabbits) weighing around 3.0-4.0 kg were used. Among 12 rabbits, 3 rabbits were sacrificed immediately after surgery and at 2, 4, and 8 weeks after surgery, respectively. Histopathologic analysis and histomorphometric analysis were conducted to evaluate bone formation in each group. RESULTS: The PRF/DDM group did not show a significantly higher degree of new bone formation in calvarial bone defects than the DDM group at 2, 4, and 8 weeks postoperatively in histopathological findings and histomorphometric results. On the other side, the rhBMP-2/DDM group showed higher degrees of new bone formation and calcification, and the lamellae of bone matrix, which are observed in mature bone tissue, were more distinctly visible in the rhBMP-2/DDM group. Moreover, the rhBMP-2/DDM group showed a significantly higher amount of new bone formation, compared to the DDM group at 4 and 8 weeks postoperatively (P<0.05) in histomorphometric results. CONCLUSION: The DDM has great potential as a carrier for the maintenance and sustained release of rhBMP-2, which has been recently receiving wide attention as a type of signaling molecules to promote bone formation.

Laryngeal granulomas in patients after two-jaw surgery - Four cases report.

BACKGROUND: Endotracheal intubation can cause focal ischemia, damage or edema to the laryngeal mucosa, and may be followed by serious complications such as vocal cord paralysis, ulcers, and granulation tissue formation. Laryngeal granuloma is rare but also a significant late complication of endotracheal intubation, and anesthesiologists should be concerned about it. CASE: We experienced four cases of laryngeal granuloma that developed after two-jaw surgery January 2017-December 2018 in our hospital and would like to report these cases with brief review of literature. CONCLUSIONS: There are frequent movements on the head and neck in maxillofacial surgery and the nasotracheal intubation should be prolonged after bimaxillary osteotomy surgery because of post-operative airway problems. This may be why two-jaw surgery may have higher occurrence of laryngeal granuloma than others.

Fiberoptic bronchoscope and C-MAC video laryngoscope assisted nasal-oral tube exchange: two case reports.

In cases of multiple facial trauma and other specific cases, the anesthesiologist may be asked to convert an oral endotracheal tube to a nasal endotracheal tube or vice versa. Conventionally, the patient is simply extubated and the endotracheal tube is re-inserted along either the oral or nasal route. However, the task of airway management can become difficult due to surgical trauma or worsening of the airway condition. Fiberoptic bronchoscopy was considered a novel method of airway conversion but this method is not useful when there are secretions and bleeding in the airway, or if the anesthesiologist is inexperienced in using this device. We report a successful airway conversion under the aid of both, a fiberoptic bronchoscope and a C-MAC video laryngoscope.

Histologic study of bone-forming capacity on polydeoxyribonucleotide combined with demineralized dentin matrix.

BACKGROUND: This study examined the osteoinductive activity of demineralized dentin matrix (DDM) from human and polydeoxyribonucleotide (PDRN) for nude mice. METHODS: Twenty healthy nude mice, weighing about 15~20 g, were used for the study. DDM from human and PDRN were prepared and implanted subcutaneously into the dorsal portion of the nude mice. The nude mice were sacrificed at 1, 2, and 4 weeks after grafting and evaluated histologically by hematoxylin-eosin and Masson's trichrome staining. The specimens were also evaluated via a histomorphometric study. RESULTS: The DDM and PDRN induced new bone, osteoblasts, and fibroblasts in soft tissues. The histological findings showed bone-forming cells like osteoblasts and fibroblasts at 1, 2, and 4 weeks. New bone formation was observed in the histomorphometric study. In particular, the ratio of new bone formation was the highest at 2 weeks compared with the first week and fourth week. CONCLUSIONS: In this study, we showed that the PDRN used in this experimental model was able to induce bone regeneration when combined to the DDM.

Expression of vascular endothelial growth factor in oral squamous cell carcinoma.

OBJECTIVES: The goal of this study was to determine the correlation of clinicopathological factors and the up-regulation of vascular endothelial growth factor (VEGF) expression in oral squamous cell carcinoma. MATERIALS AND METHODS: Immunohistochemical staining of VEGF and quantitative real-time polymerase chain reaction (RT-PCR) of VEGF mRNA were performed in 20 specimens from 20 patients with oral squamous cell carcinoma and another 20 specimens from 20 patients with carcinoma in situ as a controlled group. RESULTS: The results were as follows: 1) In immunohistochemical study of poorly differentiated and invasive oral squamous cell carcinoma, high-level staining of VEGF was observed. Significant correlation was observed between immunohistochemical VEGF expression and histologic differentiation, tumor size of specimens (Pearson correlation analysis, significance r>0.6, P<0.05). 2) In VEGF quantitative RT-PCR analysis, progressive cancer showed more VEGF expression than carcinoma in situ. Paired-samples analysis determined the difference of VEGF mRNA expression level between cancer tissue and carcinoma in situ tissue, between T1 and T2-4 (Student's t-test, P<0.05). CONCLUSION: These findings suggest that up-regulation of VEGF may play a role in the angiogenesis and progression of oral squamous cell carcinoma.

Effect on bone formation of the autogenous tooth graft in the treatment of peri-implant vertical bone defects in the minipigs.

BACKGROUND: The aim of this study was to evaluate the effect of autogenous tooth bone as a graft material for regeneration of bone in vertical bony defects of the minipigs. MATERIAL AND METHODS: Six minipigs were used in this study. Four molars were extracted in the right mandibular dentition and sent to the Korea Tooth Bank for fabrication of autogenous tooth bone. Ten days later, each extraction site was implanted with MS Implant Narrow Ridge 3.0x10mm fixture (Osstem, Seoul, Korea) after standardized 2mm-sized artificial vertical bony defect formation. Pineappleshaped Root-On type autogenous tooth bones were applied to the vertical defects around the neck area of the posterior three fixtures and the fore-most one was not applied with autogenous bone as a control group. Each minipig was sacrificed at 4, 8, 12 weeks after fixture installation and examined radiologically and histologically. Histological evaluation was done under light microscope with Villanueva osteochrome bone staining with semi-quantitative histomorphometric study. Percentage of new bone over total area (NBF) and bone to implant contact (BIC) ratio were evaluated using digital software for area calculation. RESULT: NBF were 48.15 ± 18.02%, 45.50 ± 28.37%, and 77.13 ± 15.30% in 4, 8, and 12 weeks, respectively for experimental groups. The control group showed 37.00 ± 11.53%, 32.25 ± 26.99%, and 1.33 ± 2.31% in 4,8,12 weeks, respectively. BIC ratio were 53.08 ± 19.82%, 45.00 ± 28.37%, and 75.13 ± 16.55% in 4,8,12 weeks, respectively. Those for the control groups were 38.33 ± 6.43%, 33.50 ± 29.51 %, and 1.33 ± 2.31% in 4, 8, 12 weeks, respectively. CONCLUSION: Autogenous tooth bone showed higher score than control group in NBF and BIC in all the data encompassing 4,8,12 weeks specimens, but statistically significant only 12 weeks data in both NBF and BIC.

Effectiveness of milrinone for cardiogenic shock due to massive pulmonary aspiration: a case report.

Pulmonary aspiration of gastric contents is one of the most frightening complications during anesthesia. Although pulmonary aspiration of gastric contents in general surgical patients is not common and resulting long-term morbidity and mortality are rare, severe hypoxemia and other sequelae of pulmonary aspiration continue to be reported. We report a case of massive aspiration of gastric contents during induction of general anesthesia, resulting in cardiac arrest due to severe pulmonary hypertension and myocardial infarction. Sustained cardiac arrest and shock that did not respond the conventional resuscitation was successfully treated using milrinone. The patient was discharged without complications in 20 days.

Epidural hematoma after thoracic epidural analgesia in a patient treated with ketorolac, mefenamic acid, and naftazone: a case report.

A 26-year-old male undergoing thoracotomy and bleeding control received a preoperative thoracic epidural for postoperative analgesia. On the fifth postoperative day, paralysis of both lower limbs occurred and urgent magnetic resonance imaging showed massive anterior epidural hematoma. During laminectomy and decompression, platelet dysfunction was diagnosed and preoperative non-steroidal anti-inflammatory drugs medications were supposed to the cause of platelet dysfunction. After infusion of ten units of platelet concentrate, coagulopathy was improved. We should be more careful to drugs with antiplatelet effect when using regional analgesia.

Comparison of ultrasound-guided supraclavicular block according to the various volumes of local anesthetic.

BACKGROUND: The ultrasound guidance in regional nerve blocks has recently been introduced and gaining popularity. Ultrasound-guided supraclavicular block has many advantages including the higher success rate, faster onset time, and fewer complications. The aim of this study was to examine the clinical data according to the varied volume of local anesthetics in the ultrasound-guided supraclavicular block. METHODS: ONE HUNDRED TWENTY PATIENTS WERE RANDOMIZED INTO FOUR GROUPS, ACCORDING TO THE LOCAL ANESTHETIC VOLUME USED: Group 35 (n = 30), Group 30 (n = 30), Group 25 (n = 30), and Group 20 (n = 30). Supraclavicular blocks were performed with 1% mepivacaine 35 ml, 30 ml, 25 ml, and 20 ml, respectively. The success rate, onset time, and complications were checked and evaluated. RESULTS: The success rate (66.7%) was lower in Group 20 than that of Group 35 (96.7%) (P < 0.05). The average onset times of Group 35, Group 30, Group 25, and Group 20 were 14.3 ± 6.9 min, 13.6 ± 4.5 min, 16.7 ± 4.6 min, and 16.5 ± 3.7 min, respectively. There were no significant differences. Horner's syndrome was higher in Group 35 (P < 0.05). CONCLUSIONS: In conclusion, we achieved 90% success rate with 30 ml of 1% mepivacaine. Therefore, we suggest 30 ml of local anesthetic volume for ultrasound-guided supraclavicular block.

Students' Response to the Questionnaire about the Usefulness of Concept Maps for Problem-Based Learning and the Forms of Concept Maps.

PURPOSE: Concept maps have been studied and used in diverse ways in scientific fields. This study aimed to investigate the usefulness and limitations of using concept maps during problem-based learning (PBL) in Year 3 medical students. METHODS: After each PBL module, we gathered concept maps from each pair of students and questionnaires about the usefulness and limitations of concept maps, and analyzed them. RESULTS: There were two types of concept maps, with some modifications. The students felt that concept maps provided overall understanding, analysis, and reorganization of problem cases. But, they also criticized shortage of disciplines related to drawing skills and rationales for each type of map. A strong need for expert maps and feedback for students resulted. CONCLUSION: For optimal use of concept maps, we recommend that the committee implements a plan to teach drawing skills, explains rationales for each type of map, and gives feedback to students.

The correlation between the effects of propofol on the auditory brainstem response and the postsynaptic currents of the auditory circuit in brainstem slices in the rat.

BACKGROUND: Although there have been reports showing the changes of the auditory brainstem response (ABR) waves by propofol, no detailed studies have been done at the level of brainstem auditory circuit. So, we studied the effects of propofol on the postsynaptic currents of the medial nucleus of the trapezoid body (MNTB)-lateral superior olive (LSO) synapses by using the whole cell voltage clamp technique and we compared this data with that obtained by the ABR. METHODS: 5 rats at postnatal (P) 15 days were used for the study of the ABR. After inducing deep anesthesia using xylazine 6 mg/kg and ketamine 25 mg/kg, the ABRs were recorded before and after intraperitoneal propofol injection (10 mg/kg) and the effects of propofol on the latencies of the I, III, and V waves and the I-III and III-V interwave intervals were evaluated. Rats that were aged under P11 were used in the voltage clamp experiments. After making brainstem slices, the postsynaptic currents (PSCs) elicited by MNTB stimulation were recorded at the LSO, and the changes of the PSCs by the bath application of propofol (100 microM) were monitored. RESULTS: We found small, but statistically significant increases in the latencies of ABR waves III and V and the interwave intervals of I-III and III-V by propofol. However, no significant changes were observed in the glycinergic or glutamatergic PSCs of the MNTB-LSO synpases by the application of propofol (100 microM). CONCLUSIONS: Glycinergic or glutamatergic transmission of the MNTB-LSO synapses might not contribute to the propofol-induced changes of the ABR.

Intracerebral hemorrhage in a patient with preeclampsia and HELLP syndrome which was diagnosed after caesarean section : A case report.

Intracerebral hemorrhage (ICH) is one of very dangerous complications of preeclampsia/eclampsia. We experienced postoperative ICH in a 39-year-old woman with preeclampsia and HELLP syndrome. The paturient complained severe headache and upper abdominal pain with nausea and vomiting. Her initial blood pressure was 190/120 mmHg and her heart rate was 80 beat/min. The diagnosis of preeclampsia with HELLP syndrome was confirmed by the severe hypertension and the laboratory findings. She was drowsy at the emergency room but she lost consciousness when transferring to the operation room. Caesarean section was done under general anesthesia. After the operation she could not recover self-respiration and consciousness. Her brain CT showed ICH in the basal ganglia with intraventricular hemorrhage and severe brain edema. She expired one the 5 th post operative day due to brain death and multiple organ failure. Early diagnosis is the key to treating ICH.

Dyspnea after supraclavicular brachial plexus block in a morbidly obese patient due to phrenic nerve block: A case report.

A 57-year-old woman with morbid obesity (BMI: 37.39) was scheduled for ligament reconstruction with tendon interposition of the carpometacarpal joint. A difficult supraclavicular brachial plexus block was performed using a 22-gauge regional block needle with a nerve stimulator and 40 ml of 1% mepivacaine. Approximately 10 minutes after the injection, she complained dyspnea, shortness of breath and right mid-thoracic pain. Her oxygen saturation decreased from 100% to 95%. Diagnostic workup revealed right diaphragmatic elevation caused by phrenic nerve block. General anesthesia was induced because of the unsuccessful brachial plexus block and dyspnea with chest pain. She recovered without any residual complications and was discharged on the third postoperative day. Phrenic nerve block is a common complication in supraclavicular brachial plexus block but it is usually not severe and reassurance is enough to control it. However, pre-operative physical conditions that may lead to decreased respiratory reserves, such as morbid obesity should be considered as a risk factors when conducting supraclavicular brachial plexus block.