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Brain temperature during 340-kHz pulsed ultrasound insonation: a safety study for sonothrombolysis.

BACKGROUND AND PURPOSE: Because ultrasound is used for improving thrombolysis of cerebral infarction but continuous ultrasound insonation also has significant thermal effects, we evaluated brain temperature increase and tissue destruction during pulsed ultrasound emission. METHODS: We examined 340-kHz pulsed ultrasound effects in male Wistar rats. Ultrasound was applied transcranially for 30 minutes on different power levels (1 to 7 W/cm2). Temperature was measured at different locations (brain, in the focus of ultrasound beam, inner ear, temporalis muscle, and rectum). The cooling time after 30-minute insonation for every power level was recorded, and animals were examined by postmortem brain histology (TUNEL and hematoxylin/eosin). RESULTS: Brain temperature increased within 2 to 5 minutes of insonation. Brain temperature increase and cooling time were in proportion to power level, and even with the highest intensity of 7 W/cm2 for 30 minutes, the maximum elevation of mean brain temperature was 0.9 degrees C, with the highest cooling time of 40 minutes. No deleterious side effects of this treatment could be found in histological examination. CONCLUSIONS: Using a pulsed ultrasound design, only a moderate temperature increase could be observed with no histopathological abnormalities. Deleterious side effects of mid-kilohertz ultrasound (eg, intracerebral hemorrhage) are therefore not a consequence of local brain temperature increase.

Animals↗

[Pathological jaw opening reflex after whiplash injury].

The brainstem mediated inhibitory reflex of the m. temporalis was investigated on average 3 days after the accident in 61 patients (f = 36; m = 25; mean age = 28 years +/- 9 SD) who presented an acute cervico-cephalic syndrome with posttraumatic headache and neck pain following acute whiplash injury but without neurological deficits, bone injury of the cervical spine or combined direct head trauma. We postulated a disturbed reflexive temporalis muscle inhibition in patients with 'whiplash cephalalgia', as has previously been reported for classical muscle tension headache. Latencies and durations of the early and late exteroceptive EMG suppression (ES1 and ES2) and the interposed EMG activity (IE) of the voluntarily contracted right temporalis muscle following ipsilateral stimulation of V/2 + 3 afferents were recorded. The reflex data were compared to a cohort of 69 age and sex matched normal subjects (f = 37; m = 32; mean age = 28 years +/- 7 SD). The following significant reflex changes were found in patients: a shortened duration of ES2 with delayed onset and premature ending, a slight prolongation of ES1 and IE, a delayed onset of IE and a diminished ratio of ES2:ES1 and ES2:IE. We conclude that the abnormality of the antinociceptive reflex is based on a transient dysfunction of the brainstem mediated reflex circuit following the acceleration trauma, which can be considered a neurophysiological correlate of the posttraumatic cervico-cephalic pain syndrome and may be useful as a 'biological marker' in monitoring the time course of recovery from pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Trans-antral temporalis transfer for the repair of adult cleft palates.

Temporalis muscle transfer is a versatile technique frequently used for reconstructive procedures in the maxillofacial region. However the thickness of the pedicle may interfere with masticatory function when used anteriorly in the oral cavity. To repair full-length mid-palatal defects in fully dentate patients the flap can be passed through the maxillary sinus and combined with local repair of the soft palate, thus avoiding any occlusal trauma from the posterior teeth. The operation is a single stage procedure with low morbidity and few complications, and is a useful technique for repairing the large untreated clefts frequently encountered in developing countries. The procedure is used by members of the Australian and New Zealand Association of Oral and Maxillofacial Surgeons Bangladesh Project who have operated in Dhaka teaching hospitals on a regular basis since 1991.

Adult↗

Tacks: a new technique for craniofacial fixation.

Biodegradable fixation in craniofacial surgery provides secure fixation while eliminating much of the concern over intracranial migration of metallic plates and screws. One limitation of present biodegradable systems, however, is the need for tapping the drill hole before screw insertion. Herein, a new method of rigid, biodegradable fixation with tacks (Macrapore, Inc., San Diego, CA) is described. The tacks are made of a 70:30 ratio of the L and DL form of polylactic acid (L,DL-PLA). Degradation times range from 18 to 36 months. Newer prototypes are nearly developed for more rapid dissolution times. From April 1999 to February 2000, tack fixation has been applied in 100 patients (51 males, 49 females aged 3 months to 61 years). Indications for operation were craniosynostosis (n = 33); craniofacial trauma or post-traumatic deformities (n = 11); cleft lip and palate (n = 13); craniofacial syndromes (n = 18); other diagnoses (n = 11). Patients underwent fronto-orbital advancement with cranial reshaping; monobloc osteotomy, open reduction-internal fixation of fractures; hypertelorbitism repair; cranioplasty; stabilization of grafts; major cranial reconstruction; zygomatic advancement; alveolar cleft repair; and iliac bone graft donor site protection. Tacks were also used for temporalis muscle and lateral canthal suspension. Follow-up ranged from 16 to 28 months. Complications occurred in 7 patients, 4 of whom had infections and during debridement had biodegradable implants removed. None of the complications appeared to be related to the use of tacks. The tacks are carried in a specially designed holder and may be placed by hand or with the light tap of a mallet on the tack driver. An automatic driver has been developed. Overall, the performance of the tacks has been excellent. They are easily handled by the nursing personnel and rapidly inserted by the surgeon. Stability appears to be excellent. At this time, it is probably preferable to employ tap and screws for orthognathic surgery or other osteotomies with substantial load bearing.

Absorbable Implants↗

Posttraumatic hypothermia in the treatment of axonal damage in an animal model of traumatic axonal injury.

OBJECT: Many investigators have demonstrated the protective effects of hypothermia following traumatic brain injury (TBI) in both animals and humans. Typically, this protection has been evaluated in relation to the preservation of neurons and/or the blunting of behavioral abnormalities. However, little consideration has been given to any potential protection afforded in regard to TBI-induced axonal injury, a feature of human TBI. In this study, the authors evaluated the protective effects of hypothermia on axonal injury after TBI in rats. METHODS: Male Sprague-Dawley rats weighing 380 to 400 g were subjected to experimental TBI induced by an impact-acceleration device. These rats were subjected to hypothermia either before or after injury, with their temporalis muscle and rectal temperatures maintained at 32 degrees C for 1 hour. After this 1-hour period of hypothermia, rewarming to normothermic levels was accomplished over a 90-minute period. Twenty-four hours later, the animals were killed and semiserial sagittal sections of the brain were reacted for visualization of the amyloid precursor protein (APP), a marker of axonal injury. The density of APP-marked damaged axons within the corticospinal tract at the pontomedullary junction was calculated for each animal. In all hypothermic animals, a significant reduction in APP-marked damaged axonal density was found. In animals treated with preinjury, immediate postinjury, and delayed hypothermia, the density of damaged axons was dramatically reduced in comparison with the untreated controls (p < 0.05). CONCLUSION: The authors infer from these findings that early as well as delayed posttraumatic hypothermia results in substantial protection in TBI, at least in terms of the injured axons.

Amyloid beta-Protein Precursor↗

Differential roles of periodontal mechanoreceptors of working-side posterior teeth in triggering nonworking-side temporalis activities.

The purpose of this study was to examine how the periodontal sensory inputs of working-side maxillary posterior, teeth affect nonworking-side anterior temporalis activities at the starting jaw position of the slow-closing phase in mastication. Six subjects with normal occlusion were asked to bite an incisal block to maintain the initial jaw position of the slow-closing phase and to generate jaw-closing muscle activities. Bipolar needle electrodes were inserted into the nonworking-side anterior temporalis to record spike discharges from a single motor unit. To stimulate the periodontal mechanoreceptors, mechanical stimulations were applied to the working-side maxillary first molar, first and second premolar in bucco-palatal, palato-buccal, and apical directions. Meanwhile, we examined changes in the discharge frequency of the motor unit activities of the nonworking-side anterior temporalis. We found that the palato-buccal stimulation to the working-side maxillary first molar and the apical stimulation to each working-side maxillary posterior tooth significantly increased the nonworking-side anterior temporalis activities; however, palato-buccal and bucco-palatal stimulations applied to the first and second premolar didn't. Thus, differential responses of the nonworking-side anterior temporalis are found by the working-side maxillary first molar and premolar stimulations. These findings may be due to some differences in function between molar and premolar.

Adult↗

Exteroceptive suppression of temporalis muscle activity: a blind study of tension-type headache, migraine, and cervicogenic headache.

Exteroceptive suppression of temporalis muscle activity (ES2 duration) has been reported to be reduced in chronic tension-type headache in previous open studies (with varying stimulus and analysis methods). We studied ES2 duration and latency in 11 patients with chronic tension-type headache, 10 patients with cervicogenic headache, 11 migraine patients, and 9 headache-free control subjects. The investigator was blinded as to the diagnostic category. Electrical stimuli of 0.5 ms duration and at least three times sensory threshold (median 9.6 mA) were used. ES2 was obtained in all but one (control) subject and the control ES2 duration mean was 33.5 (SD 8.5) ms (80% EMG amplitude reduction criterion). Mean ES2 duration differences were not found between the four groups. None of the headache patients had ES2 durations below the control group range. ES2 duration tended to decrease with increasing duration of headache history. Consistent asymmetries of ES2 latency and duration were not found among patients with (unilateral) cervicogenic headache. Thus, the role of ES2 in headache diagnosis still seems to be unsettled.

Adult↗

Exteroceptive suppression of temporalis muscle activity: methodological and physiological aspects.

In recent years studies of the suppression of EMG activity in temporalis muscle induced by stimulation in the trigeminal territory have opened new perspectives in headache research. The various methods that have been used in different laboratories are reviewed and some of the physiological modulations of temporalis exteroceptive suppression are described. Among different methods of recording, averaging 10 full-wave rectified EMG responses produces results with acceptable variability and discomfort. In order to obtain maximal responses the intensity of the stimulation should reach at least 20 mA. To avoid habituation of the second temporalis exteroceptive suppression period (ES2), the stimulation frequency has to be at 0.1 Hz or below. The level of voluntary contraction is not a critical variable as long as it reaches 50% of maximum. Some physiological variations of temporalis suppression are well documented. In females, ES2 is shorter during menstruation than at mid-cycle and correlated with the estradiol/progesterone ratio in plasma. Conditioning temporalis ES2 by a preceding peripheral stimulus markedly reduces its duration, which is partly reversible by naloxone. Various pharmacological agents are able to modify temporalis ES2: its duration is increased by 5-HT1 antagonists, but decreased by 5-HT uptake blockers; contradictory results have been obtained with acetylsalicylic acid. These results suggest that inhibitory brain-stem interneurons mediating temporalis ES2 are inhibited by serotonergic afferents, probably from the raphe magnus nucleus, and that the latter receives an excitatory input from the periaqueductal gray matter and other limbic structures, in part via opioid receptors.

Analysis of Variance↗

Perimenstrual migraine: effect of Estraderm TTS and the value of contingent negative variation and exteroceptive temporalis muscle suppression test.

In 20 patients with pure menstrual migraine either Estraderm TTS 50 patches (E) or placebo (P) patches were applied during three successive menstrual cycles, randomly allocated to the treatment sequences E-P-E or P-E-P. Clinical neurophysiological tests, contingent negative variation (CNV) and exteroceptive temporalis muscle suppression test (ETST) were performed before treatment. The predictive value of these tests regarding the efficacy of Estraderm TTS was studied. Neither the number, duration and severity of the migraine attacks, nor the consumption of analgesics and ergotamine differed significantly during Estraderm TTS and placebo treatment. The ETST was consistent with migraine in 35% (95% confidence interval 15.4 to 59.2) of the patients. The CNV in 55% (31.5 to 76.9), and both tests in 25% (8.7 to 49.1%). Regarding the prediction of the Estraderm TTS effect on the migraine attacks, the specificity of the ETST, CNV and the combination of ETST with CNV, calculated for the first two cycles, was respectively 81.8% (48.2 to 97.7), 45.5% (16.8 to 76.6) and 80% (28.4 to 99.5). For the last two cycles these values were respectively 75% (42.8 to 94.5), 50.0% (21.1 to 87.9) and 71.4% (29.0 to 96.3). The sensitivity of the tests was respectively 62.5% (24.5 to 91.5), 62.5% (24.5 to 91.5) and 66.7% (22.3 to 95.7) in the first 2 cycles. In the last 2 cycles 50.0% (15.1 to 84.3), 62.5% (24.5 to 91.5) and 60% (14.7 to 94.7). This study did not demonstrate an effectiveness of Estraderm TTS in perimenstrual migraine, except for the subgroup of perimenstrual migraine patients in whom the ETST test results were consistent with migraine.

Administration, Cutaneous↗

Exteroceptive suppression of temporalis muscle activity during migraine attack and migraine interval before and after treatment with sumatriptan.

We compared the early (ES1) and late (ES2) exteroceptive suppression (ES) periods of temporalis muscle activity in 18 migraine patients during both the migraine interval and migraine attack and investigated the effect of sumatriptan and placebo on ES parameters. The measurements were performed in a balanced sequence at four different times on each patient, twice during the migraine interval and once in each of two migraine attacks. First ES1 and ES2 were measured (stimulus intensity 20 mA, stimulus duration 0.2 ms, stimulation frequency 2 Hz, averaging of 10 responses), then the medication was given on a double-blind basis with an autoinjector using either 6 mg sumatriptan or a placebo solution. Thirty minutes after application the measurements were repeated. No significant differences were found in early and late exteroceptive suppression latencies and durations between baseline measurements. Treatment did not affect the latencies of ES1 and ES2. While sumatriptan caused a significant increase in ES1 duration (p < or = 0.05) both during the migraine interval and during the migraine attack, placebo showed no significant effect on ES1 duration. Treatment with sumatriptan during the migraine attack was accompanied by a significant increase in the duration of ES2 (p < or = 0.05), but no significant changes in the durations of the late suppression periods were observed under any other conditions. The results do not support the assumption that under the experimental conditions chosen migraine attacks are accompanied by a paroxysmal change in the brain-stem mechanisms involved in the modulation of the ES parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Spatial and temporal changes in myosin heavy chain gene expression in skeletal muscle development.

Seven myosin heavy chains (MyHC) are expressed in mammalian skeletal muscle in spatially and temporally regulated patterns. The timing, distribution, and quantitation of MyHC expression during development and early postnatal life of the mouse are reported here. The three adult fast MyHC RNAs (IIa, IIb, and IId/x) are expressed in the mouse embryo and each mRNA has a distinct temporal and spatial distribution. In situ hybridization analysis demonstrates expression of IIb mRNA by 14.5 dpc, which proceeds developmentally in a rostral to caudal pattern. IId/x and IIa mRNAs are detectable 2 days later. Ribonuclease protection assays demonstrate that the three adult fast genes are expressed at approximately equal levels relative to each other in the embryo but at quite low levels relative to the two developmental isoforms, embryonic and perinatal. Just after birth major changes in the relative proportions of different MyHC RNAs and protein occur. In all cases, RNA expression and protein expression appear coincident. The changes in MyHC RNA and protein expression are distinct in different muscles and are restricted in some cases to particular regions of the muscle and do not always reflect their distribution in the adult.

Animals↗

Reconstruction of the temporomandibular joint using a temporalis graft with or without simultaneous orthognathic surgery.

PURPOSE: This article reports the outcome of free temporalis fascia and muscle graft (TFG) reconstruction of the temporomandibular joint (TMJ) with and without simultaneous orthognathic surgery (SOS). MATERIALS AND METHODS: Twenty-nine patients (45 joints) were evaluated retrospectively. Group 1 consisted of 17 patients (16 women 1 man) and 30 joints. Fifteen (88%) patients had sagittal split ramus osteotomies (SSRO); 8 (53%) of these patients also had Le Fort I osteotomies, and 2 patients (12%) had only Le Fort I osteotomies with TFG. Group 2 consisted of 12 patients (15 joints) who received only TFG and no SOS. RESULTS: Group 1 had 9 patients (53%) with an incisal opening greater than 35 mm, 11 joints (37%) with greater than 6 mm lateral excursive movement, and 11 patients (65%) were asymptomatic postoperatively. Average follow-up was 57.4 months (range, 23 to 69 months). Group 2 had eight patients (67%) with an incisal opening greater than 35 mm, six joints (40%) with greater than 6 mm lateral excursive movement, and seven patients (58%) were asymptomatic postoperatively. Average follow-up was 55.1 months (range, 48 to 64 months). CONCLUSION: TFG with and without SOS produced similar treatment outcomes in comparing groups 1 and 2. No significant differences were observed for the number of patients with an incisal opening > 35 mm (P = .703), lateral excursion > 6 mm (P = 1.00), and successful elimination of pain (P = 1.00), even though group 2 had a significantly greater number of patients (P < 0.01) that were operated on unilaterally. Combining treatment outcomes for both groups, the number of previous joint surgeries significantly affected success (P < .01). The presence of osteoarthritic changes did-not significantly affect treatment outcome (P = .187).

Adolescent↗

Wolff Award 1992. Exteroceptive suppression of temporalis muscle activity in patients with chronic headache and in normal volunteers: methodology, clinical and pathophysiological relevance.

Exteroceptive suppression of temporalis muscle activity was studied in patients with chronic headache and in healthy controls. Among different methods of recording, averaging 10 full-wave rectified EMG responses produces results with acceptable variability and discomfort. The late temporalis exteroceptive suppression period (ES2) is reduced on average in patients with chronic tension-type headache; this finding has been reproduced by several independent laboratories. Mean duration of temporalis ES2 is also diminished, but to a lesser degree, in daily drug abuse headache and, as shown by others, in episodic tension-type headache. It is normal in migraine between attacks, cluster headache and various types of symptomatic headaches. Temporalis ES2 may be decreased in untreated patients with major depression. In healthy volunteers, temporalis ES2 duration is reduced by a short-lasting painful stimulus to peripheral limbs after a delay of 50 to 60 ms, and by a sub-motor threshold electromagnetic stimulation to the contralateral cerebral cortex after a delay of 20 to 30 ms. In contrast, long-lasting trains of peripheral painful stimuli have no effect. Various pharmacological agents are able to modify temporalis ES2. Its duration is increased by 5-HT antagonists, but decreased by 5-HT uptake blockers. Pharmacological effects may differ between controls and patients. Considering these results and available data on the anatomo-functional organization of masticatory reflexes, we postulate that temporalis ES2 is a marker of the excitability of interneuronal nets in the ponto-medullary reticular formation. In chronic tension-type headache, excitability of these interneurons is decreased because of inadequate control by the serotonergic raphe magnus nucleus and the periaqueductal gray matter. Dysfunctioning of the latter structures might be caused by abnormal limbic inputs to the brain stem. Some steps of this pathophysiological hypothesis can be verified by modern neurophysiological techniques.

Analysis of Variance↗

[Long-term results of two temporalis muscle transfer procedures in correction of paralytic lagophthalmos].

OBJECTIVE: To compare the long-term results and possible complications of a modified temporalis muscle transfer (TMT) with the Johnson's procedure in correction of paralytic lagophthalmos. METHODS: From September 1997 to March 2000, paralytic lagophthalmos due to leprosy in 92 patients were corrected with TMT. The 89 cases (127 to eyes including 51 unilateral and 38 bilateral) followed up 3 years after operation were analyzed. There were 69 males and 20 females with ages ranging from 18 to 65 years (52 years on average). The duration of lagophthalmos was 1-22 years with an average of 8.2 years. And 36 eyes were complicated with lower eyelid ectropion. Sixty-five eyes were corrected with Johnson's procedure (Johnson's TMT group), 62 with the modified TMT procedure (modified TMT group). The modifications were as follows: (1) omitting the fascial strip in the lower eyelid to avoid postoperative ectropion. (2) fixing the fascial strip of the upper eyelid to the middle or inner margin of the tarsal palate depending on the degree of the lagophthalmos to avoid possible ptosis of the upper eyelid. RESULTS: In Johnson's TMT group, the mean lid gap on light closure was reduced to 3.1 mm postoperatively from 7.7 mm preoperatively; and the mean lid gap on tight closure was reduced to 0.5 mm postoperatively from 6.1 mm preoperatively. The symptoms of redness (73.7%) and tearing (63.7%) disappeared or were improved postoperatively. However, ectropion and ptosis occurred in 24 eyes and 9 eyes respectively. The overall excellent and good rate was 58.5%. In the modified TMT group, the mean lid gap on light closure was reduced to 3.3 mm postoperatively from 7.5 mm preoperatively; and the mean lid gap on tight closure was reduced to 0. 6 mm postoperatively from 6. 3 mm preoperatively. The symptoms of redness (90.9%) and tearing (71.0%) disappeared or were improved postoperatively, and no ectropion or ptosis was found except one ectropion. The overall excellent and good rate was 87.1%, which was significantly higher than that of Johnson's group (P < 0.01). CONCLUSION: The modified TMT is an efficiency and simple procedure with very few complications, and thus is strongly recommended for use when TMT is an indication.

Adolescent↗

Cosmetic reconstruction of temporal defect following pterional [corrected] craniotomy.

BACKGROUND: Depression of the temporal fossa that is often caused by atrophy of the temporalis muscle or superficial temporal fat pad may be an unavoidable defect following pterional craniotomy. Various techniques have been previously described to correct this disfiguring defect. Most techniques, however, require drilling holes into the cranium or the synthetic grafts for attachment of the temporalis muscle. METHODS: A simple method is described by which a temporal fossa depression is repaired with methylmethacrylate bone cement and a new superior temporal line is created for attachment of the temporalis muscle without the need to drill suture holes into the acrylic or the cranium. RESULTS AND CONCLUSIONS: The technique described has been used on several patients with excellent cosmetic outcome.

Craniotomy↗

An anatomic study of the temporoparietal fascial flap.

OBJECTIVE: To clarify the neurovascular relationships in the temporoparietal fascial flap and to access its possible use as a sensate free of a pedicled flap. DESIGN: Anatomic dissections (gross) and examinations (histologic) were performed on 10 fresh cadaver heads. SETTING: Academic tertiary care facility, Boston, Mass. MAIN OUTCOME MEASURES: To determine the relationship of the sensory innervation (the auriculotemporal nerve) to the vascular supply (the superficial temporal artery) of the temporoparietal fascial flap, in addition to determining safe incisions and the level of flap elevation that will preserve the sensory supply to the flap. RESULTS: There is a consistent relationship of the auriculotemporal nerve to the superficial temporal artery allowing for auriculotemporal nerve preservation with standard flap elevation techniques and easy nerve identification in this cadaveric study. CONCLUSION: A clear understanding of the anatomic pattern allows for the potential creation of a sensate fascial flap or vascularized nerve graft that would add a potential additional dimension to this fascial flap.

Adipose Tissue↗

Occult hepatocellular carcinoma metastasising to the left temple diagnosed by fine-needle aspiration biopsy.

Although hepatocellular carcinoma (HCC) is relatively rare in Western countries, it is one of the most prevalent cancers worldwide. Metastatic spread outside the liver is common and typically occurs in the setting of advanced disease. Metastatic disease is the initial presentation of HCC in less than 5% of cases and even fewer are diagnosed by cytology. We present the cytological findings in an 85-yr-old man of a soft tissue mass in the left temple, which suggested the diagnosis of an occult HCC. Fine-needle aspiration biopsy showed moderately cellular smears with large malignant epithelial cells present in fragments, with apposition of endothelial cells to the tumour cells. Deposits of non-refractile green pigment consistent with bile were present. Investigations revealed abnormal liver function tests, and a large mass replacing much of the liver. In view of the cytology and clinico-radiological correlation, a diagnosis of metastatic HCC was made.

Aged, 80 and over↗