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PubMed1993

NMR-contrast enhancement of experimental brain tumors with MnTPPS: qualitative evaluation by in vivo relaxometry.

The applicability of the synthetic manganese porphyrin MnTPPS as tumor-selective MRI-contrast agent for brain tumors was investigated quantitatively by in vivo relaxometry. To exclude toxic effects of side products, the purification method for MnTPPS was improved. As a result, MnTPPS+Cl- (free acid) with a purity of more than 99.8% was obtained. For the in vivo quantification of the contrast effect the magnetization M(0) and the transversal relaxation time T2 were evaluated in different regions of rat brains with or without implanted gliomas and in temporal muscle. Measurements were performed before and after the application of MnTPPS. The ratio of the magnetization M(0) (TR = 3.5 sec) of the tissue under investigation and the contralateral striatum was defined as contrast ratio Rc(0). Without MnTPPS Rc(0) of edema (0.93 +/- 0.08) and tumor (0.91 +/- 0.07) did not differ from normal brain tissue (corpus callosum: 0.96 +/- 0.07; cortex: 0.98 +/- 0.05). T2 of edema (110 +/- 12 msec) and intracranial tumor (93 +/- 7 msec) were significantly longer than in normal tissue (corpus callosum: 73 +/- 8 msec; parietal cortex: 75 +/- 6 msec; striate nucleus: 78 +/- 7 msec, p < .01). Two hours after the injection of MnTPPS, magnetization of neoplastic tissue was selectively enhanced (TR = 3.5 sec), and T2 was reduced. The smallest dose of 0.06 mmol/kg body weight (bw) increased Rc(0) to 1.12 +/- 0.04, and 0.38 mmol/kg to 1.30 +/- 0.13 (p < .01). T2 of tumor decreased to 85 +/- 6 msec after 0.06 mmol/kg and to 65 +/- 6 msec after 0.38 mmol/kg bw.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Increased overbite and craniomandibular disorders--a clinical approach.

This study investigated the effect of a maxillary fixed lingual arch with anterior bite plane on adult patients with craniomandibular disorders (CMD) and increased overbite. The sample comprised 11 patients with an increased overbite (greater than 5 mm) and a normal or Class II molar relationship. The main CMD symptoms were daily tension headache in the region of anterior temporal muscles and/or pain or clicking in the temporomandibular joint. Previous treatment with stabilization splints, removal bite plates, or occlusal grinding had not given satisfactory results. When the maxillary lingual arch with anterior bite plane was fitted, molar separation was approximately 4 mm, and occlusal contact occurred only between the acrylic bite plane and the lower six anterior teeth. The permanent appliance could be removed only by the orthodontist. All patients reported relief of CMD symptoms 1 to 2 weeks after initiation of treatment. After a mean time of 3 months, a flatter curve of Spee, molar contact, and reduced overbite could be seen in all cases. The excessive overbite had decreased approximately 3.4 mm. Subsequent treatment involved orthodontic or prosthetic therapy to normalize and stabilize the sagittal and vertical dimensions. After an average posttreatment observation period of 2 years, all patients remained free of CMD pain.

Adult↗
PubMed1996

Audiogenic seizures following global ischemia induced by chest compression in Long-Evans rats.

Transient global ischemia was used to produce a rat model of generalized tonic-clonic epilepsy. Controlled chest compression in ketamine-anesthesized Long-Evans rats produced transient global ischemia by mechanically preventing the heart from pumping blood. Circulation was restored by standard cardiopulmonary resuscitation techniques. With a temporal muscle (skull) temperature of 35 +/- 0.4 degrees C, 75% (76/102) of the rats survived 7 min of chest compression. Generalized seizures could be evoked in 78% (59/76) of the surviving rats by a 60 s exposure to a loud sound (bell, 110 dB) beginning 24 h after the ischemic episode. The seizure patterns seen resembled those described by Maresceaux (1987) for genetically seizure-prone Wistar rats. Susceptibility to sound-induced seizures declined with time, with wide variations in recovery rate between individuals; one rat showed a daily sound-induced seizure for over 5 months. Seizures were attenuated or blocked by treatment with carbamazepine or sodium valproate. This model is similar to the great vessel occlusion model used by Kawai et al. (1995), but is less invasive. We believe it will be useful in the evaluation of therapies for acquired generalized (grand mal) seizures.

Acoustic Stimulation↗
PubMed2005

Activity of inferior head of human lateral pterygoid muscle during standardized lateral jaw movements.

OBJECTIVE: (a) To describe the changes in electromyographic (EMG) activity from selected jaw muscles during a standardized lateral jaw movement with the teeth together, and (b) to investigate the effects on jaw muscle activity of changes in both the rate of lateral jaw movement and the relative magnitude of jaw-closing force. DESIGN: In 16 healthy volunteers, recordings were made using a jaw-tracking system, of mid-incisor point (MIPT) movements, as well as EMG activity from the contralateral inferior head of the lateral pterygoid muscle (IHLP), and bilateral anterior and posterior temporalis, masseter and submandibular muscles, during lateral jaw movement tasks at two speeds and two closing force levels with the teeth together. RESULTS: The IHLP was the only muscle to show a consistent increase in activity in association with the outgoing phase of the task and a decrease during the return phase. Under high closing force at slow speed, the EMG activities of the IHLP and bilateral anterior temporalis and masseter muscles were significantly (p < 0.05) higher than those under a low closing force, while there was no significant change (p > 0.05) in bilateral posterior temporalis and submandibular muscles. The change from slow to fast lateral movement at low force did not significantly (p > 0.05) alter the mean activity except for the IHLP (increase in activity) and the contralateral anterior temporalis (decrease in activity). CONCLUSIONS: The data suggest that the IHLP is one of the principal jaw muscles involved in a lateral jaw movement with the teeth together while the other jaw muscles may play a contributory or facilitatory role.

Adolescent↗
PubMed2004

Mild hypothermia enhances the neuroprotective effects of FK506 and expands its therapeutic window following transient focal ischemia in rats.

FK506 (tacrolimus), an immunosuppressant, reportedly reduces ischemic brain injury following transient middle cerebral artery occlusion (MCAO) in rats. The authors previously reported that the therapeutic window of FK506 in this model is more than 1 h, but less than 2 h. The aim of the present study is to determine whether mild hypothermia (35 degrees C) enhances the neuroprotective effects of FK506 and expands its therapeutic window. Sprague-Dawley rats were subjected to 2 h MCAO followed by 24 h reperfusion. Animals were randomly divided into four groups: (I) vehicle-treated normothermic group; (II) FK506-treated normothermic group; (III) vehicle-treated hypothermic group; (IV) FK506-treated hypothermic group. Animals received a single injection of FK506 (0.3 mg/kg) or vehicle intravenously at 2 h after ischemic induction. During ischemia, temporal muscle and rectal temperatures were maintained at 37 degrees C in the normothermic animals and at 35 degrees C in the hypothermic animals. Infarct volumes and neurological performance were evaluated at 24 h after reperfusion. The combination of FK506 and mild hypothermia significantly reduced infarct volume (cortex, -61%; striatum, -31%) and edema volume (cortex, -57%; striatum, -41%), while mild hypothermia or FK506 alone failed to improve ischemic brain damage. Furthermore, this combination also provided for the best functional outcome. These results demonstrate that the combination of FK506 and mild hypothermia significantly reduces ischemic brain damage following transient MCAO in rats, and expands the therapeutic window for FK506. This therapy may be a new approach for treatment of acute stroke.

Animals↗
PubMed2006

The role of peripheral and central sodium channels in mediating brain temperature fluctuations induced by intravenous cocaine.

While cocaine's interaction with the dopamine (DA) transporter and subsequent increase in DA transmission are usually considered key factors responsible for its locomotor stimulatory and reinforcing properties, many centrally mediated physiological and psychoemotional effects of cocaine are resistant to DA receptor blockade, suggesting the importance of other non-DA mechanisms. To explore the role of cocaine's interaction with Na+ channels, rats were used to compare locomotor stimulatory and temperature (NAcc, temporal muscle and skin) effects of repeated iv injections of cocaine (1 mg/kg) with those induced by procaine (PRO 5 mg/kg), a short-acting local anesthetic with negligible effect on the DA transporter, and cocaine methiodide (COC-MET 1.31 mg/kg), a quaternary cocaine derivative that is unable to cross the blood-brain barrier. While PRO, unlike cocaine, did not induce locomotor activation, it mimicked cocaine in its ability to increase brain temperature following the initial injection and to induce biphasic, down-up fluctuations following repeated injections. This similarity suggests that both these effects of cocaine may be driven by its action on Na+ channels, a common action of both drugs. While COC-MET also did not affect locomotor activity, it shared with cocaine and PRO their ability to increase brain temperature but failed to induce temperature decreases after repeated injections. These findings point toward activation of peripheral Na+ channels as the primary mechanism of rapid excitatory effects of cocaine and inhibition of centrally located Na+ channels as the primary mechanism for transient inhibitory effects of cocaine. DA receptor blockade (SCH23390+eticlopride) fully eliminated locomotor stimulatory and temperature-increasing effects of cocaine, but its temperature-decreasing effects remained intact. Surprisingly, DA receptor blockade also altered the temperature fluctuations caused by PRO and COC-MET, suggesting that some of the central effects triggered via Na+ channels are in fact DA-dependent. Finally, repeated administration of PRO to animals that had previous cocaine experience led to conditioned locomotion and potentiated temperature-increasing effects of this drug. It appears, therefore, that, in addition to the central effects of cocaine mediated via interaction with the DA transporter and potentiation of DA uptake, interaction with peripheral and central Na+ channels is important for the initial physiological and, perhaps, affective effects of cocaine, likely contributing to the unique abuse potential of this drug.

Anesthetics, Local↗
PubMed2004

Krypton laser-induced photothrombotic distal middle cerebral artery occlusion without craniectomy in mice.

Recent advances in genetical engineering of the mouse have highlighted the importance of reproducible and less invasive models of cerebral ischemia in mice. In this paper, we developed minimally invasive and reproducible model of distal middle cerebral artery (MCA) occlusion in mice using krypton (Kr) laser-induced photothrombosis. C57BL/6 or BALB mice (n=8 each) were anesthetized with halothane. The skin was cut, the temporal muscle was retracted, and the right distal MCA was observed through the skull. A Kr laser beam of wavelength 568 nm was focused onto the MCA over the intact skull. Upon laser irradiation, intravenous administration of a rose bengal solution was begun. After 4 min of irradiation, the laser beam was refocused on the MCA just proximal to the first spot, and another 4-min irradiation was performed. Then, the right common carotid artery (CCA) was ligated. Three days later, the brain was removed, and infarct volume was determined. Infarction confined almost solely to the cortical area was produced in each mouse. Mean infarct volume in C57BL/6 mice was 25.2+/-13.7 mm3. The BALB mice group showed significantly larger and more reproducible infarction (44.1+/-5.2 mm3; the coefficient of variation was 12%) than did C57BL/6 mice (P<0.005). Our photothrombosis model of stroke in mice can be performed without craniectomy, and its reproducibility is satisfactory when using BALB mice.

Animals↗
PubMed2005

Electrically induced gel-to-gel phase-transition in neurons.

At the end of transcardial perfusions with ice-cold physiological saline for 30 min or with isoosmotic potassium chloride for 5 min, but immediately before perfusion fixation, condenser-discharge electric shocks were administered to rats through surface electrodes pressed onto the temporal muscles of the scalped skull. As a result, striking ultrastructural compaction came about in numerous neurons thinly scattered in certain brain areas. Its features displayed a high degree of similarity to those previously observed following the in vivo administration of the same kind of electric shocks. This surprising independence from the actual state of metabolism questions whether the ultrastructural compaction, induced either in vivo or post mortem, is the result of any cascade of enzyme-mediated processes. On the other hand, a physical mechanism, phase transition propagated by non-covalent free energy stored in a cytoplasmic gel structure, which was proposed recently to explain a mechanically induced similar ultrastructural compaction, appears to apply also to the present case.

Animals↗
PubMed2004

Differences in motor recruitment and resulting kinematics between low back pain patients and asymptomatic participants during lifting exertions.

BACKGROUND: Low back disorders are a prevalent problem in society today and may lead to chronic debilitating low back pain. Developing our understanding of temporal muscle and kinematic patterns during manual material handling tasks may provide insight for preventing the cascading series of events leading to chronic low back pain. METHODS: Sixty-two low back pain patients and 61 asymptomatic participants performed a variety of lifting exertions that varied in lift origin horizontal and vertical distance, lift asymmetry, and weight. Electromyographic activity of 10 trunk muscles as well as trunk and pelvic kinematics was recorded during each exertion. Differences in muscle activation and kinematic parameters were compared between low back pain patients and asymptomatic participants as a function of experimental conditions. FINDINGS: Both the left and right erector spinae activated significantly earlier and were on significantly longer in low back pain patients compared to asymptomatic participants. The horizontal and vertical location of the lift influenced the EMG and kinematic differences between the low back pain patients and asymptomatic participants. INTERPRETATION: These finding indicate that low back pain patients would be exposed to increase muscle activity resulting in higher spine loads for a greater length of time compared to asymptomatic participants. The longer exposure time to increased spine load may lead to greater risk of future low back injury and cascading events leading to debilitating low back pain. The longer muscle activation time suggests that low back pain patients have changed their motor program from an open to a closed loop system.

Adult↗
PubMed2005

Passive resistance increases differentially in various jaw displacement directions.

OBJECTIVES: In the present study, the passive resistance of the human jaw system was quantified in relation to the three-dimensional jaw displacement and the Posselt-envelope, using both in vivo measurements and computer simulation. METHODS: In eight subjects, the jaw was passively displaced with a step-wise increasing force in three orthogonal directions. Muscle relaxation was monitored using electromyography (EMG) with visual feedback. A biomechanical model of an average human system was used to examine the contributions of the jaw muscles. RESULTS: The largest excursion was found for the vertical direction. Protrusive and lateral directions were more restricted. In protrusive and lateral directions, the jaw could generally move beyond the Posselt-envelope. The stiffness of the jaw increased with proceeding jaw displacement in all directions. The stiffness was larger in the protrusive direction than in the vertical and lateral directions. The model's predictions of stiffness were comparable to the in vivo measurements. However, in protrusive direction, the maximum jaw displacement was larger than in vivo. The estimated passive muscle forces showed that vertical displacement was mainly restricted by the complete group of closing muscles, while protrusive and lateral jaw displacement was restricted by selective individual muscles. CONCLUSIONS: The human jaw system has larger motion range in the protrusive and lateral directions than can be exploited by active muscle use. Stiffness of jaw displacement is higher in the protrusive direction compared to the vertical and lateral directions.

Adult↗
PubMed2004

The effect of clenching on condylar position: A vector analysis model.

STATEMENT OF THE PROBLEM: Clinicians often disagree about the acceptable position of the condyle in the articular fossa. Agreement as to what position the condyle-disk assembly assumes on the articular eminence while subjected to the forces of the elevator muscles of the mandible is important. PURPOSE: This simulation study investigated the position of the condyle-disk assembly on the articular eminence while subjected to the forces of the elevator muscles of the mandible during clenching. MATERIAL AND METHODS: Using the 2 conditions of static equilibrium, a vector analysis of a 2-dimensional model of the temporomandibular joint was developed. The dynamics of the condyle-disk assembly during muscle loading were analyzed. The vector sum of the masticatory muscle forces was determined by assuming that the maximum force developed by each contributing muscle was proportional with the physiologic cross section of the muscle. The effect of the resultant force vector of the combined muscle action applied to the condyle was analyzed for the orthogonal and acute angle situations. RESULTS: When the vector sum was orthogonal on the eminence, the condyle was in stable equilibrium. The stable equilibrium was found in the anterior-superior position in the fossa. When the vector sum was at an acute angle to the eminence, the condyle was subject to a translation force that displaced it into the anterior-superior equilibrium position. CONCLUSION: Within the limitation of this study, vector analysis suggested that the anterior-superior position of the condyle-disk assembly on the eminence was the most stable equilibrium position. All other tested positions of the condyle were less stable and maintained at the expense of other structures.

Algorithms↗
PubMed2004

[Geniculate ganglion tumors. Therapeutic and reconstructive management].

We present five cases of patients diagnosed of a facial nerve tumoral lesion localised at the Geniculate Ganglion and all of which underwent surgical resection. The initial symptoms were in four cases of peripheral facial nerve paralysis and in the fifth case facial paresis. Two trans-mastoid extralabyrinthine approaches were performed and one through a combined path (middle fossa and trans-mastoid) with reconstruction of the facial nerve through a termino-terminal graft. In the fourth case, an approach through fossa media was done, and did not include nerve reconstruction but palliative treatment with a palpebral gold plaque. In the fifth case, a modified trans-labyrinthine approach with facial-hypoglossus termino-terminal anastomosis. Histological diagnosis was 3 neurinomas and 2 hemangiomas. Of the termino-terminal grafts two managed a functional Grade III of the House-Brackmann classification. The third one sustained a Grade VI and therefore a suspension with temporal muscle was carried out. The patient with facial-hypoglossus anastomosis is in a functional Grade IV. Geniculate ganglion tumors are in their majority benign and their treatment is the total resection of the tumor. Nerve reconstruction can be primary or deferred with the aid of a nerve graft or anastomosis, being necessary palliative techniques when resection is not possible.

Adult↗
PubMed1999

Control of brain temperature during experimental global ischemia in rats.

Temperature control during experimental ischemia continues to be of major interest. However, if exposure of brain tissue is necessary during the experiment, regional heat loss may occur even when the core temperature is maintained. Furthermore, valid non-invasive brain temperature monitoring is difficult in small rodents. This paper describes a method for both monitoring and maintenance of brain temperature during small animal preparations in a stereotaxic frame. The device used includes an ear-bar thermocouple probe and a small near-infrared radiator. The new equipment permitted to maintain peri-ischemic brain temperature at a desired level while carrying out non-invasive continuous recordings of cerebral blood flow (laser Doppler-flowmetry) and of electrical brain function (EEG). In contrast, without extracranial heat application, superficial and basal brain temperatures decreased during global cerebral ischemia by 4.1 +/- 0.1 and 4.6 +/- 0.4 degrees C (mean +/- SEM), respectively, returning to baseline values at 15-30 min of reperfusion while rectal (core) temperature remained stable at baseline values. The ear-bar thermocouple probe (tympanic membrane) reliably reflected basal brain temperature, and temperature in superficial brain areas correlated well with that in the temporal muscle. Our data show that the new system allows to exclude unwanted hypothermic neuroprotection, and does not interfere with optical and electrical measurement techniques.

Animals↗
PubMed2002

Does nociceptin play a role in pain disorders in man?

Nociceptin-immunoreactive cellbodies were detected in the human trigeminal ganglion, while no such fibers were identified in the temporal artery or in dermal tissue from the neck region. In four healthy subjects receiving nociceptin into the temporal muscle in an open labeled design no pain was detected. In 10 healthy subjects who received 200pmol of nociceptin into tender non-dominant trapezius muscles in a placebo-controlled, randomized, balanced, and double-blinded design local tenderness increased (P=0.025) while no pain was noted. Thus, the action of nociceptin should be searched for in the trigeminal ganglion and/or in the central nervous system (CNS).

Adult↗
PubMed1996

Surgical anatomy of the buccal nerve.

The buccal nerve may be damaged during surgical procedures which require an incision along the external oblique ridge of the mandible and this study was undertaken to clarify its surgical anatomy. The course and relationships of the nerve were determined in 20 formalin-fixed cadaver specimens. The number of major branches of the nerve ranged from 4 to 8 and a mean of 3 branches was present as the nerve crossed the external oblique ridge. In 14 dissections the main trunk of the nerve crossed the external oblique ridge within 3 mm of the deepest concavity, but in the other 6 it was 7-12 mm below this point. We conclude that incisions even 12 mm below the deepest concavity in the external oblique ridge could result in buccal nerve damage.

Aged↗
PubMed2000

Free fat transplantation for facial tissue augmentation.

PURPOSE: This article reviews the lipofilling technique using a fat tissue suspension obtained by manual or vacuum machine-assisted suction. PATIENTS AND METHODS: Between 1989 and 1997 14 patients were treated by lipofilling. All patients were female; 6 were treated for cheek and zygomatic area augmentation for Romberg syndrome (2 cases) and bilateral facial lipodystrophy (4 cases); 4 were treated for nasolabial fold correction, 3 for lip augmentation, and 1 for correction of systemic lupus erythematosus (LES) scars. RESULTS: Good results were obtained in the treatment of the moderate Romberg syndrome case, with 3 stages of fat tissue transplantation from the abdominal area, in the severe Romberg syndrome case that was treated with 3 stages of lipofilling after a primary surgical procedure consisting of augmentation of the zygomatic region using a composite temporal flap of calvaria bone and temporal muscle, in the 4 cases of bilateral facial lipodystrophy, and in the 4 cases of nasolabial fold correction with 3 to 4 stages of lipofilling. Poor results were obtained in lip augmentation, and bad results were obtained in correction of the LES scars. CONCLUSIONS: Using the lipofilling technique with cannulas of 3 to 4 mm in diameter and low-power manual aspiration to preserve the integrity of the fat cells, good results were achieved in 10 of the 14 patients treated. The poor results occurred in areas of reduced vascularity and high motility.

Adipose Tissue↗
PubMed1997

Direct and indirect revascularization for moyamoya disease surgical techniques and peri-operative complications.

We have performed surgical treatment for Moyamoya disease using the superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-arterio-myo-synangiosis (EDAMS). In this paper, the surgical technique of combined revascularization for Moyamoya disease as well as peri-operative complications are discussed. Craniotomy and dural opening were extensively carried out to expose the brain surface as widely as possible. Dissection of the STA, which is the most powerful resource of direct revascularization, should be carefully carried out using a surgical microscope. The temporal muscle and middle meningeal artery, which have the most potential as sources of indirect revascularization, must be preserved. STA-MCA anastomosis to the frontal branch of the middle cerebral artery is indispensable for improving cerebral circulation of the frontal lobe. A small arachnoid membrane opening and water-tight closure are also important to avoid post-operative subdural and subcutaneous fluid collection. Ischemic events disappeared immediately after surgery in most cases. However, in several cases, transient ischemic attacks recurred for several months after the surgery. Chronic subdural hematoma was seen in two cases.

Adolescent↗