Biomedical subjects

R Gassner

Publications and source records attributed to R Gassner.

At least 19 recordsLinked to original sources

PubMed2005

[Dentoalveolar trauma. Analysis of 4763 patients with 6237 injuries in 10 years].

PURPOSE: The purpose of this study was to evaluate the overall place of dental trauma in facial injuries. This was a retrospective investigation based on the analysis of a large amount of dentoalveolar injuries over a 10-year period. PATIENTS AND METHODS: Between 1991 and 2000, 4763 of 9543 patients suffering from oral and maxillofacial injuries, sustained dentoalveolar trauma. Records of 6237 different dental injury patterns were reviewed according to the five main injury mechanisms: age, sex, type of injury, cause of accident, and frequency of dentoalveolar trauma. They were statistically analyzed using frequency distribution, chi-square test, t-test, Mann-Whitney U test, Kolmogorov-Smirnov test, and logistic regression analysis. RESULTS: Household and play (2117), sports (1533), traffic accidents (438), acts of violence (426), and work-related accidents (201) were noted. A total of 4763 patients had 2988 subluxations, 2356 showed crown fractures, 444 had avulsions, 176 root fractures, 154 intrusions, and 119 patients suffered from concussions. This number of patients accounts for the prevalence of 49.9% for dentoalveolar trauma among all facial injuries. CONCLUSION: Only the analysis of a large number of injuries reveals the risk of suffering from dentoalveolar trauma. Due to this fact, preventive methods can be recommended and demanded more effectively.

Adolescent↗

PubMed2005

Diagnostic quality of dynamic high-resolution ultrasonography of the TMJ--a pilot study.

The aim of this study was to compare sensitivity, specificity, accuracy and positive and negative predictive value for high-resolution ultrasonography (HR-US) in diagnosing degenerative changes, effusion and disk displacement using magnetic resonance imaging (MRI) as a reference. Over a period of 6 months, 100 patients with TMJ disorders (200 TMJs) were investigated by an experienced radiologist with HR-US and magnetic resonance imaging (MRI). The MRI investigation showed degenerative changes in 190 joints (95%), while an effusion was found in 59 (29.5%) joints. At closed-mouth position a disc dislocation was found in 138 joints (69%) and in maximum-mouth-opening position disc dislocation was diagnosed in 76 joints (38%). In the determination of degenerative changes HR-US showed a sensitivity of 94%, a specificity of 100% and an accuracy of 94%. In the detection of effusion HR-US yielded a sensitivity of 81%, a specificity of 100% and an accuracy of 95%. In the determination of disk displacement at closed-mouth position HR-US showed a sensitivity, specificity and an accuracy of 92% each. At maximum-mouth-opening position HR-US reached a sensitivity of 86%, a specificity of 91% and an accuracy of 90%. The results of the current study imply that HR-US is a valuable diagnostic imaging method of the TMJ which can be used as an alternative method to a MRI-investigation, but is yet not able to replace it. Further studies have to be done to reduce false-negative results.

False Negative Reactions↗

PubMed2005

The effects of guided tissue regeneration (GTR) on modified Le Fort I osteotomy healing in rabbits.

Osteogenesis following surgery depends on the osteoblasts at the wound site. Fibrous nonunions may be the result of differential and rapid migration of fibroblasts compared to osteoblasts into the wound. The present study was designed to test this hypothesis through the use of guided tissue regeneration (GTR) in a rabbit model. Bilateral, Le Fort I osteotomies (n=20) were produced in the maxillae of 10 New Zealand White rabbits. The segments were advanced 6mm and rigidly fixed using microplates and screws. One side was covered with a resorbable collagen membrane or left uncovered. Rabbits were followed for four weeks with radiographs and the maxillae were harvested for histology. Cephalometry revealed that membrane-covered defects had significantly (P<0.01) reduced defect area (by approximately 70%) compared to uncovered defects. Histologically, membrane-covered defects showed more organized osteogenesis and less fibrous tissue than uncovered defects. Histomorphometry revealed that membrane covered defects had significantly (P<0.05) reduced defect areas (by approximately 20%) compared to uncovered defects. While findings suggest that GTR can facilitate osseous wound healing in Le Fort I osteotomies, results also caution against relying exclusively on two-dimensional radiography to assess bony wound healing in lieu of three-dimensional imaging and evaluations.

Absorbable Implants↗

PubMed2004

Maxillofacial fractures masking traumatic intracranial hemorrhages.

Maxillofacial trauma may mask intracranial injuries prompting intensive care treatment. The purpose of this study was to identify whether craniofacial fracture patterns predispose patients with maxillofacial fractures to different types of intracranial hemorrhages. Within 7 years, 6649 patients with craniomaxillofacial injuries were admitted for treatment. The charts of the patients were analyzed according to age, sex, cause and mechanism of injury, type and location of facial injury, and intracranial trauma; 2195 sustained maxillofacial fractures. Statistical analyses were followed by logistic regression analyses for the four main types of intracranial hemorrhage to determine the impact of the different maxillofacial fractures. Intracranial hemorrhages in 212 patients (9.7%) occurred as epidural (2.5%), subdural (4.3%), subarachnoid (5.3%), and intracerebral hemorrhages (6.3%). Le Fort, orbit, nose, zygoma, and maxillary fractures increased the risk for accompanying intracranial hemorrhage by two- to fourfold (P < 0.05). Basal skull fractures caused a multiplication of the risk up to 17-fold, while fractures of the cranial vault were associated with a risk up to 14-fold. Nearly 10% of patients with craniomaxillofacial fractures sustain intracranial hemorrhages requiring frequently immediate neurosurgical intervention. Those patients, suffering from central midface fractures and skull base fractures, are prone to highly significant elevated risks of intracranial hemorrhage.

Adolescent↗

PubMed2003

Placental growth from the first to the second trimester of pregnancy in SGA-foetuses and pre-eclamptic pregnancies compared to normal foetuses.

The aim of this study was to determine placental growth between 12-22 weeks in normal pregnancies compared to pregnancies complicated by foetal SGA and maternal pre-eclampsia (PE). The placentae of 1199 women were measured 3D sonographically at 12, 16 and 22 weeks of gestation. Placental volume growth was then calculated. Neonatal birthweight, birth centile and the occurrence of pre-eclampsia were recorded in every woman and correlated with placental growth (four groups: normals, SGA, PE, SGA+PE). SGA-placentae are already smaller at 12 weeks but then develop in a similar way to normal placentae. PE placentae are slightly, but significantly, larger at 12 weeks, grow rapidly until 16 weeks and then stop growing normally between 16 and 22 weeks. If SGA goes together with PE, both placental volume (PV) at 12 weeks as well as growth is reduced significantly. Nevertheless, placental growth between week 12 and 22 is too heterogeneous to justify using this method as a clinical tool, but it can provide new information on placental physiology underlying unfavourable obstetric outcomes.

Adult↗

PubMed2002

Maxillofacial trauma due to work-related accidents.

Even though numerous reports on maxillofacial trauma exist, only a few give detailed information about work-related maxillofacial injuries. The purpose of this study was to reveal the significance of maxillofacial injuries related to accidents occurring at work by evaluating a large number of patients with maxillofacial injuries over a 9-year period. Out of the 8704 trauma patients treated between 1991 and 1999 in the Department of Oral and Maxillofacial Surgery at the University of Innsbruck, Austria, 463 (5.4%) were injured at work. All charts were reviewed and analyzed according to age, gender, cause of accident, occupation, type of injury, location and frequency of fractures. The highest incidence of maxillofacial injury was found among construction workers (a total of 124 patients, 26.8%), followed by craftsmen (102 patients, 22.0%) and office employees (69 patients, 14.9%). The sex distribution showed an overall male-to-female ratio of 11.8:1 and those in the age group most affected were between 20 and 29 years of age. The most frequent cause of injury was a blow in 48.4%, followed by falls and falls over obstacles, accounting for 27.9% and 7.1%, respectively. Of all trauma, 45.4% (210 persons) sustained 423 maxillofacial fractures, 31.7% (147 patients) suffered 232 dento-alveolar injuries, and 21.2% (98 people) showed 430 soft-tissue injuries. One-fifth (20.7%) of all patients displayed concomitant injuries with cerebral and cranial trauma being the most common. The probability of sustaining maxillofacial trauma at work is correlated to the nature of the occupation. Individuals (mostly men) using tools or machines at work are exposed to a much higher risk of work-related maxillofacial trauma.

Accidents, Occupational↗

PubMed2001

Cyclic tensile strain suppresses catabolic effects of interleukin-1beta in fibrochondrocytes from the temporomandibular joint.

OBJECTIVE: To discern the effects of continuous passive motion on inflamed temporomandibular joints (TMJ). METHODS: The effects of continuous passive motion on TMJ were simulated by exposing primary cultures of rabbit TMJ fibrochondrocyte monolayers to cyclic tensile strain (CTS) in the presence of recombinant human interleukin-1beta (rHuIL-1beta) in vitro. The messenger RNA (mRNA) induction of rHuIL-1beta response elements was examined by semiquantitative reverse transcriptase-polymerase chain reaction. The synthesis of nitric oxide was examined by Griess reaction, and the synthesis of prostaglandin E2 (PGE2) was examined by radioimmunoassay. The synthesis of proteins was examined by Western blot analysis of the cell extracts, and synthesis of proteoglycans via incorporation of 35S-sodium sulfate in the culture medium. RESULTS: Exposure of TMJ fibrochondrocytes to rHuIL-1beta resulted in the induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2), which were paralleled by NO and PGE2 production. Additionally, IL-1beta induced significant levels of collagenase (matrix metalloproteinase 1 [MMP-1]) within 4 hours, and this was sustained over a period of 48 hours. Concomitant application of CTS abrogated the catabolic effects of IL-1beta on TMJ chondrocytes by inhibiting iNOS, COX-2, and MMP-1 mRNA production and NO, PGE2, and MMP-1 synthesis. CTS also counteracted cartilage degradation by augmenting expression of mRNA for tissue inhibitor of metalloproteinases 2 that is inhibited by rHuIL-1beta. In parallel, CTS also counteracted rHuIL-1beta-induced suppression of proteoglycan synthesis. Nevertheless, the presence of an inflammatory signal was a prerequisite for the observed CTS actions, because fibrochondrocytes, when exposed to CTS alone, did not exhibit any of the effects described above. CONCLUSION: CTS acts as an effective antagonist of rHuIL-1beta by potentially diminishing its catabolic actions on TMJ fibrochondrocytes. Furthermore, CTS actions appear to involve disruption/regulation of signal transduction cascade of rHuIL-1beta upstream of mRNA transcription.

Animals↗

PubMed2001

Tumor necrosis factor alpha-dependent proinflammatory gene induction is inhibited by cyclic tensile strain in articular chondrocytes in vitro.

OBJECTIVE: To understand the intracellular mechanisms of the action of mechanical strain on articular chondrocytes during inflammation. METHODS: One of the major mediators responsible for cartilage destruction in inflamed articular joints is tumor necrosis factor alpha (TNFalpha). Therefore, in this study we examined the intracellular mechanisms of actions of cyclic tensile strain (CTS) on the recombinant human TNFalpha (rHuTNFalpha)-induced proinflammatory pathways in primary cultures of chondrocytes. The expression of messenger RNA (mRNA) for TNFalpha-dependent proinflammatory proteins was examined by semiquantitative reverse transcriptase-polymerase chain reaction. The synthesis of proinflammatory proteins was examined by Western blot analysis in cell extracts, followed by semiquantitative measurement of bands using densitometric analysis. Nitric oxide production was measured by Griess reaction, and prostaglandin E2 production was assessed by radioimmunoassays. The proteoglycan synthesis in chondrocytes was assessed by incorporation of Na2(35)SO4 in chondroitin sulfate proteoglycans. RESULTS: By exposing chondrocytes to CTS in the presence of TNFalpha in vitro, we showed that CTS is an effective antagonist of TNFalpha actions and acts as both an antiinflammatory signal and a reparative signal. CTS of low magnitude suppresses TNFalpha-induced mRNA expression of multiple proinflammatory proteins involved in catabolic responses, such as inducible nitric oxide synthase, cyclooxygenase 2, and collagenase. CTS also counteracts cartilage degradation by augmenting induction of tissue inhibitor of metalloproteinase 2. Additionally, CTS augments the reparative process via abrogation of TNFalpha-induced suppression of proteoglycan synthesis. Nonetheless, CTS acts on chondrocytes in a TNFalpha-dependent manner, since exposure of chondrocytes to CTS alone had no effect on these parameters. CONCLUSION: CTS of low magnitude acts as an effective antagonist of TNFalpha not only by inhibiting the TNFalpha-dependent induction of proinflammatory proteins upstream of mRNA transcription, but also by augmenting the proteoglycan synthesis that is inhibited by TNFalpha.

Animals↗

PubMed2001

Prevalence of cervical spine injuries in patients with facial trauma.

OBJECTIVE: Injuries to the spine may accompany facial trauma. By using a large computerized database the goal of this case control study was to assess the association between facial and cervical spine injuries among patients sustaining facial trauma. STUDY DESIGN: During a period of 4 years (1995 to 1998) 3083 patients, 10 years or older, with facial injuries were admitted to the University Hospital of Innsbruck's Department of Oral and Maxillofacial Surgery for facial trauma. Records were analyzed for cause of injury, age and gender distribution, frequency and type of injury, and frequency of cervical spine injuries in relation to facial trauma and concomitant injuries. Two hundred six (6.7%) of these patients had experienced a concomitant cervical spine injury (case group). All other patients (2877) were assigned to the control group of facial trauma only. RESULTS: Facial trauma patients with concomitant cervical spine injuries were significantly older (mean age, 42 vs 34 years); no difference existed for the female/male ratio of 30:70. Sports trauma was the main cause of facial trauma in the control group (37.4%), yet traffic accidents accounted for 43.7% of combined facial and cervical spine injuries in the case group. Central mid face fractures dominated in the case group and lateral mid face fractures in the control group. In the case group cervical spine fractures and dislocations occurred in 19.2%. None of them showed evidence of paralysis. Concomitant brain injuries occurred in 21.6% of the case group and 8.8% of the control group. For patients sustaining facial trauma, logistic regression analysis revealed reduced risks for additional cervical spine injuries in younger patients, female patients, absence of brain injury, and in patients with facial soft tissue lesions alone (58.2%) or dental trauma alone (77.5%). CONCLUSION: The results of this study underline the importance of proper clinical and computed tomographic evaluation in cases of facial fractures for recognition of additional cervical spine trauma. Detection of cervical spine trauma can be missed, especially when pain or symptoms from other parts of the body dominate. The typical patient with concomitant neck and facial trauma is male, 40 years old, and usually involved in a traffic accident.

Adolescent↗

PubMed2001

The incidence of combined facial and cervical spine injuries.

BACKGROUND: The association between facial and cervical spine injuries has been documented. However, only severe spinal injuries were included in previous analyses. It was the purpose of this study to evaluate the incidence of and risk factors for these injury combinations including the complete injury spectrum. METHODS: Between 1995 and 1997, 4,907 patients with cervical spine injuries were treated at our hospital. One hundred five (2.14%) of these patients had suffered a concomitant facial injury. This group was compared with the group of patients with cervical spine injury but without facial trauma. RESULTS: The majority of cases (98%) consisted of minor lesions to both regions. With increasing severity of cervical spine trauma, the risk for facial injury increased. Age and male gender represent significant (p < 0.05) risk factors for combined injuries. CONCLUSION: Patients sustaining cervical spine trauma have a small but real chance of injuring their face as well. The cervical spine must be examined carefully, whenever facial injuries are present.

Adolescent↗

PubMed2000

[Cytokine-induced nitric oxide production of joint cartilage cells in continuous passive movement. Anti-inflammatory effect of continuous passive movement on chondrocytes: in vitro study].

PURPOSE: The temporomandibular joint is a place of motion where release of proinflammatory cytokines like interleukin-1 beta (IL-1 beta) induces cartilage destruction via production of nitric oxide (NO). The purpose of this study was to evaluate the effects of continuous passive motion in the form of cyclic stretch on the synthesis of inducible nitric oxide synthase (iNOS). METHODS: Articular chondrocytes were harvested from rabbit cartilage slices and cultured in F12 medium supplemented with 10% fetal calf serum. Subsequently, cells (10(5)/ml per well) were transferred to Flexercell plates, grown to 90% confluency, and subjected to one of the following regimens: (1) no mechanical strain (10 Hz, 20% elongation rate); (2) rhIL-1 beta (1 ng/ml); (3) mechanical strain; (4) mechanical strain and rhIL-1 beta. The cells were exposed to cyclic stretch for 24 h. Thereafter, cells were trypsinized and centrifuged on microscope slides in a cytospin centrifuge. The presence of iNOS was determined by indirect immunoperoxidase staining using polyclonal rabbit anti-iNOS as primary antibodies, and goat anti-rabbit IgG conjugated with horseradish peroxidase (HRP) as secondary antibodies. Diaminobenzidine was used as substrate for HRP. Total NO production was spectrophotometrically measured in the supernatants of cultures using Greiss reaction. All experiments were done in triplicates and the statistical significance was analyzed by Student's t-test. RESULTS: Cells with treatment 1 and 3 did not exhibit presence of iNOS. IL-1 beta-treated cells in group 2 exhibited intense peroxidase staining. Cells in group 4 exposed to IL-1 and mechanical stress showed staining with considerably less intensity. Control cells treated with normal rabbit IgG as a primary antibody did not exhibit peroxidase staining. The data were further confirmed by measurement of statistically significant differences of NO levels in supernatants assessed in the four different treatment groups. CONCLUSION: Our findings suggest that continuous passive motion exerts anti-inflammatory effects on chondrocytes, downregulating the quantity of iNOS-positive cells. Since NO acts as an intracellular, transcellular, and cytotoxic molecule, it has a basic importance for proper post-traumatic and postoperative TMJ function as well as the course and therapy of inflammatory TMJ diseases.

Animals↗

PubMed2000

[Healing behavior and bone regeneration of maxillary osteotomies in the experimental rabbit model. Effect of osteosynthesis and guided bone regeneration].

PURPOSE: The development of fibrous nonunions following orthognathic surgery is thought to result from an interaction of biomechanical stress and the differential and more rapid migration of fibroblasts compared to osteoblasts into the wound site during healing. The present study was designed to test this hypothesis through the manipulation of guided tissue regeneration and osteotomy fixation techniques in an experimental rabbit model. MATERIALS AND METHODS: Bilateral critical size (4 mm) defects (n = 24) were produced in the maxillae of 12 adult New Zealand White rabbits. The maxillary segments were rigidly or nonrigidly fixed using bone microplates and screws or osteosynthetic wires. The defects were then covered with a resorbable collagen membrane or left uncovered. The rabbits were followed for 4 weeks with serial dorsoventral and lateral oblique cephalographs and the maxillae were then harvested for histological analysis. RESULTS: Radiographic and histomorphometric analysis revealed that rigidly fixed defects, covered with membrane, showed the most rapid and organized new bone formation. The rigidly fixed defects with membrane averaged approximately 40% more new bone in the osteotomy site than the rigidly fixed defects with no membrane. Nonrigidly fixed defects with no membrane also showed an ingrowth of fibroblasts and fibrous nonunions. CONCLUSION: These results suggest that an interaction between the decreased fibrous tissue ingrowth through guided tissue regeneration and osteotomy segment stability from rigid fixation prevented postoperative fibrous nonunions and facilitated new bone regeneration and osteotomy site healing in this rabbit model.

Animals↗

PubMed2000

Effect of arthrocentesis and hydraulic distension on the temporomandibular joint disk position.

OBJECTIVE: Recent studies have suggested arthrocentesis and hydraulic distension as an effective treatment modality in patients demonstrating clinical findings consistent with the diagnosis of disk displacement without reduction, normal range of motion thereby being restored and pain of the temporomandibular joint reduced. In view of the fact that only a few studies have been performed to verify the biologic concept of disk displacement without reduction as a diagnostic and therapeutic approach in patients with "closed-lock" symptoms, the purpose of this study was to investigate whether temporomandibular joint-related variable disk position might be linked to cessation of related signs and symptoms associated with the performance of arthrocentesis and hydraulic distension. STUDY DESIGN: The study compared 15 patients, each of whom was assigned a clinical unilateral temporomandibular joint-related diagnosis of internal derangement (ID) type III (disk displacement without reduction) in combination with capsulitis/synovitis. Clinical diagnoses were made according to the Clinical Diagnostic Criteria for Temporomandibular Disorders. Bilateral sagittal and coronal magnetic resonance images were obtained immediately preoperatively and at 2-month follow-up to establish the presence or absence of associated types of ID. Temporomandibular joint-related pain, level of function, and mandibular range of motion were assessed preoperatively and the data were compared with the respective 2-month follow-up findings. RESULTS: Comparison of the pretreatment temporomandibular joint side-related data revealed the temporomandibular joint side with an ID-III in combination with capsulitis/synovitis to be associated with significantly more magnetic resonance imaging diagnoses of ID than of an absence of ID (P <.001) and with significantly more disk displacement without reduction than disk displacement with reduction (P <.001). At the 2-month follow-up, clinical evaluation showed a significant reduction in temporomandibular joint-related pain during function (P <.001), a significant reduction in the prevalence of temporomandibular joint-related diagnoses of capsulitis/synovitis (P <.001) and ID-III (P <.01), and a significant increase in mandibular range of motion (P <.01). There was no change in the prevalence rates of associated temporomandibular joint side-related IDs. CONCLUSIONS: The results confirm the concept of disk displacement as a diagnostic approach but not as a therapeutic approach for patients presenting with signs and symptoms of unilateral ID-III in combination with capsulitis/synovitis. In terms of clinical decision-making in temporomandibular disorder-related instances of ID, magnetic resonance imaging may be used as a diagnostic method for identifying the diagnostic validity of the variable "disk-condyle relationship."

Adolescent↗

PubMed2000

Traumatic dental injuries and Alpine skiing.

The purpose of this study was to determine the occurrence and type of traumatic dental injuries after maxillofacial injuries as a result of Alpine skiing. During an 8-year period (from January 1991 to December 1998) 7600 patients with facial injuries were registered at the Department of Oral and Maxillofacial Surgery, University of Innsbruck, Austria. Of 784 patients with skiing-related facial injuries (524 males, 260 females) 326 (41.6%) sustained injuries to 639 teeth. The age groups predominantly affected were between 7 and 32 years. Luxation injuries occurred in 338 (53%) teeth, fractures accounted for 270 tooth injuries (42%), and only 35 (5%) were lost at the place of the accident. Of skiers with traumatic dental injuries 58% had concomitant soft tissue injuries, while 23.3% had associated facial bone fractures. The most common causes of injury were falls in 42% (329 patients) and collisions with other persons in 24.1% (189 patients). Being hit by one's own sports equipment (11%) was the third most common cause. Collisions with obstacles accounted for 9% and lift accidents for 5.6% of injuries. The probability of suffering dentoalveolar trauma during skiing varied depending on the injury mechanism. There was a 2-fold risk for dentoalveolar trauma when colliding with objects, a 3.5-fold risk when hit by one's own equipment and a 8.5-fold risk during lift accidents. Dental injuries occurred in about 2% of all injured skiers. Dental health professionals should be aware of the high incidence and the distribution of dental trauma and facial injuries caused by skiing.

Accidental Falls↗

PubMed2000

Histomorphology of rabbit thigh muscles: establishment of standard control values.

The thigh muscles of New Zealand White (NZW) rabbits are frequently used in experimental surgery, particularly for evaluation after reinnervation or ischaemia. Although histomorphometric analyses are regularly performed, morphological data for untreated thigh muscles in previously unoperated animals are not available. Specimens from the rectus femoris (RF), vastus medialis (VM) and adductor magnus (AM) muscles from both thighs were harvested in 7 untreated rabbits and were processed for histomorphometric evaluation. The right RF and VM were harvested in a further 5 rabbit hindlimbs after experimental denervation and reinnervation of the contralateral RF and subsequently processed for histomorphometric analysis. Muscle fibre type distribution, diameter and connective tissue content were evaluated on serial transverse cryosections reacted for ATPase and NADH tetrazolium reductase activity and statistical analysis was performed. In all untreated animals RF revealed the highest proportion of type I muscle fibres (right: 8.4+/-4%, left: 11.4+/-4.9%), whereas VM showed the highest percentage of IIa fibres (right: 31.9+/-5.5%, left: 28.3+/-7.8%) and AM the highest proportion of IIb/d fibres (right: 80.5+/-8.6%, left: 84.4+/-6.3%). Fibre type distribution and diameter in rabbits after contralateral experimental operations revealed a statistically significant difference from the data obtained in bilaterally untreated animals. Knowledge of the morphology of untreated muscles is fundamental to the understanding of changes induced by intervention to the ipsi and/or contralateral thigh muscles.

Analysis of Variance↗

PubMed2000

Growth factor and cytokine gene expression in mechanically strained human osteoblast-like cells: implications for distraction osteogenesis.

OBJECTIVE: An understanding of bone cellular biology is a basic necessity to understanding events such as distraction osteogenesis. The goal of this study was to determine the effect of continuous cyclic mechanical stretch as a fundamental event in distraction osteogenesis on the expression of 3 bone growth factors, transforming growth factor-beta 1 (TGF-beta1), insulin-like growth factor 1 (IGF-1), basic fibroblast growth factor (bFGF) and 2 cytokines, interleukin (IL)-1 (IL-1) and 6 (IL-6) in human osteoblast-like cells. MATERIAL AND METHODS: A human osteoblast-like cell line, SaOS-2, capable of forming a ground substance and mineralizing it, was maintained. Cells were transferred to 6-well plates with flexible silicon bottoms grown to confluence and either subjected to tensile stretch for different time intervals or used as the control group. RNA was isolated to conduct Northern blot analysis for the expression of 3 bone growth factors, transforming TGF-beta1, IGF-1, bFGF, and 2 cytokines, IL-1 and IL-6. RESULTS: After 8 hours, mRNA for TGF-beta1 and IGF-1 increased in the experimental group, whereas bFGF decreased but cytokines IL-1 and IL-6 were not affected. At 16 hours, TGF-beta1, IGF-1, and bFGF showed increased levels of mRNA; IL-6 showed a slight increase. After 24 hours, TGF-beta1, IGF-1, bFGF, and IL-6 had increased mRNA levels. IL-1beta did never show significant alterations in mRNA production as compared with the control. CONCLUSION: Tensile stretch on osteoblast-like cells alter local regulation of bone formation, increasing the expression of bone growth factors, whereas catabolic cytokines are unaffected. These findings suggest a direct effect of mechanical strain on osteoblasts and may be the driving factors of bone growth during distraction.

Blotting, Northern↗

PubMed2000

Temporomandibular joint pain: relationship to internal derangement type, osteoarthrosis, and synovial fluid mediator level of tumor necrosis factor-alpha.

OBJECTIVES: The purpose of this study was to investigate whether patients with temporomandibular joint (TMJ)-related pain classified as capsulitis/synovitis may be linked to magnetic resonance imaging (MRI) findings of internal derangement, osteoarthrosis, or the synovial fluid aspirate findings of tumor necrosis factor-alpha (TNF-alpha) level. STUDY DESIGN: The study comprised 23 patients with temporomandibular disorders (TMD), who had nonchronic pain (pain onset < or =6 months) and a unilateral TMJ-related diagnosis of capsulitis/synovitis. Bilateral sagittal and coronal magnetic resonance images were obtained to establish the presence or absence of internal derangement, osteoarthrosis, or both. TMJ synovial fluid aspirates were obtained from the pain and contralateral nonpain sides to determine the TNF-alpha level. RESULTS: Comparison of the TMJ side-related data showed a significant relationship between the clinical TMD diagnosis of capsulitis/synovitis and the MRI diagnoses of TMJ internal derangement (P =.002) and of TMJ internal derangement type (P =.04). The mean TNF-alpha level in synovial fluid aspirates from TMJs assigned a clinical TMD diagnosis of capsulitis/synovitis was significantly higher than in those obtained from contralateral nonpain sides (P =.001). There was no correlation between the clinical diagnosis of capsulitis/synovitis and the MRI diagnosis of TMJ osteoarthrosis (P =.13) or between the MRI diagnosis of TMJ osteoarthrosis and that of TMJ internal derangement (P =.70) or TMJ internal derangement type (P =.33). CONCLUSIONS: The results suggest that the TMJ pain condition of capsulitis/synovitis is related to TMJ-side specific MRI diagnoses of internal derangement and internal derangement type, and synovial fluid aspirate findings of TNF-alpha level. The data confirm the concept of elevated mediator level as a diagnostic approach for patients presenting with TMJ-related pain. MRI and synovial fluid aspirates may be used as diagnostic methods for evaluating TMJ-related pain conditions.

Adolescent↗

PubMed2000

Effect of temporomandibular joint arthrocentesis on synovial fluid mediator level of tumor necrosis factor-alpha: implications for treatment outcome.

Temporomandibular joint (TMJ) pain is a predominant sign and symptom in patients with temporomandibular disorder, and a common cause of chronic orofacial pain. Arthrocentesis of the upper joint space proved to be effective in reducing TMJ-related pain and reestablishing normal mandibular range of movement in patients diagnosed for a 'closed lock'. Using the therapeutic approach of arthrocentesis in TMJ-related instances of capsulitis/ synovitis (C/S) with a recency of first pain onset of < or =6 months, the purpose of the present study was to evaluate whether the TMJ-related variable synovial fluid (SF) level of TNF-alpha may be linked to the cessation of related signs and symptoms associated with the performance of arthrocentesis and hydraulic distension. In 23 patients with a specific temporomandibular disorder diagnosis of unilateral C/S with a recency of first pain onset of < or =6 months, TMJ SF aspirates were obtained from the pain and contralateral non-pain sides immediately before and after arthrocentesis. Visual analog scales were used for pre- and postoperative self-assessment of TMJ-related pain during function, while enzyme-linked immunosorbent assays were applied for measurement of the tumor necrosis factor-alpha (TNF-alpha) concentration. With a mean SF TNF-alpha level of 13.91 ng/ml associated with the pain side, and a mean SF TNF-alpha level of 7.73 ng/ml associated with the non-pain side, a statistically significant difference was found between the sample groups (P=0.001). Arthrocentesis led to a significant intraoperative decrease of the respective preoperative SF TNF-alpha levels, namely 61.64% (P=0.000) on the pain side and 89.50% (P=0.000) on the non-pain side, while reduction of TMJ-related pain during function was 73.17%, (P=0.000). Clinical evaluation showed a significant reduction in the prevalence of TMJ-related diagnoses of C/S (P<0.001). There was no change in the prevalence of associated TMJ-related diagnoses of internal derangement. In view of the fact that the described technique of TMJ SF analysis may be suggested as a valuable diagnostic method for the detection of biochemical SF events, the results of this study should encourage research in its potential uses so that it can become established as a reliable diagnostic approach. Further, the findings may support the concept of bilateral arthrocentesis to be effective in the treatment of patients with a unilateral specific TMD diagnosis of non-chronic C/S.

Adolescent↗