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PubMed2005

Calcium sparks in skeletal muscle fibers.

Ca(2+) sparks monitor transient local releases of Ca(2+) from the sarcoplasmic reticulum (SR) into the myoplasm. The release takes place through ryanodine receptors (RYRs), the Ca(2+)-release channels of the SR. In intact fibers from frog skeletal muscle, the temporal and spatial properties of voltage-activated Ca(2+) sparks are well simulated by a model that assumes that the Ca(2+) flux underlying a spark is 2.5 pA (units of Ca(2+) current) for 4.6 ms (18 degrees C). This flux amplitude suggests that 1-5 active RYRs participate in the generation of a typical voltage-activated spark under physiological conditions. A major goal of future experiments is to estimate this number more precisely and, if it is two or more, to investigate the communication mechanism that allows multiple RYRs to be co-activated in a rapid but self-limited fashion.

Amphibians↗
PubMed1975

[Electromyographic characteristics of movement disorders in tumors of the temporal lobe of the brain].

The author studied the basic regularities of EMG changes in 26 patients with tumors of the temporal lobe, in 30 normals and in patients with tumors in the frontal lobes. The studies depicted an inhibition of the muscular electrogenesis in the form of a drop of the amplitude of muscular potentials at rest, in respirative and synergical changes of the muscular tone, in tests on extension and voluntary muscular contraction. There was also a mildly changed structure of the EMG and crude disorders of the reciprocal relations in muscular antagonists. The author stresses that there was no significant asymmetry of EMG parameters. An inhibition of muscular electrogenesis was more expressed in patients with malignant tumors and in the remote stages of the hypertensive syndrome.

Brain Neoplasms↗
PubMed1997

Combined encephalo-arterio-synangiosis and encephalo-myo-synangiosis in the treatment of moyamoya disease.

From January 1990 to December 1995, a total of nine cases of Moyamoya disease were treated at the National Taiwan University Hospital with combined encephalo-arterio-synangiosis (EAS) and encephalo-myo-synangiosis (EMS). There were five males and four females and their ages ranged from 6 months to 31 years. Of these, two cases had their first symptom as intracranial hemorrhage and the rest of the cases had ischemic manifestations. Surgical treatment with combined EAS and EMS was performed on 16 hemispheres of the nine cases. The superficial temporal artery with its anterior and posterior branches was isolated and fixed to the pial surface. Then, the muscle pedicle from the bivalved temporal muscle was used as a dural graft to cover the artery. All the cases showed good neovascularization on follow-up angiography performed at 2-3 months after surgery. These two patients with hemorrhagic symptoms were followed for 52 and 61 months, respectively. Neither of these two cases showed recurrent bleeding. For patients with ischemic symptoms, the follow-up period ranged from 8 to 73 months (mean 41.7 months). All the patients showed improvement in their clinical symptoms.

Adolescent↗
PubMed1989

[Mandible function in taking construction bite for activator].

Functional effects of construction bite for activator (Andresen type) especially on lateral pterygoid muscle, as well as the positional changes of the mandible, hyoid bone and surface EMGs from bilateral anterior temporal (TA) and masseter (MM) muscle, were studied on the electric force scale, MKG, EMG and cephalometric radiographs in 14 subjects with anterior cross bite in mixed dentition. The cephalometric radiographs were taken at the start of each patient's treatment. One was taken with the mandible in the intercuspal position and one was also taken with the activator in the mouth at the overjet improvement. The activator patients were divided into two groups because of differences in the direction of movement of the hyoid bone in the FH plane. In group O (7 patients), the movement of the hyoid bone was at an oblique angle to the FH plane, while in group D (7 patients) the movement ot the hyoid bone with nearly direct below angle to FH plane. The patients were further divided into three types because of differences in the distance between the hyoid bone and mental spine, and combined with the groups OA (3 patients), OB (2 patients), OC (2 patients), DA (5 patients), DB (2 patients) and DC (Naught). The results obtained were as follows: The forces for the construction bite for groups O and D were 2.71 Kg and 2.72 kg, respectively. Type OC required significantly heavier force. (p less than 0.05) In the condylar test, O group was significantly smaller at the start of treatment, but not after overjet improvement. Type OA and OB were also significantly smaller at the start of treatment. (p less than 0.05) Velocity of opening for group D was significantly (p less than 0.05) faster at the start of treatment, but not after that. There was no significant difference in EMGs between the groups, with activator in the mouse D group much increased as it EMGs. The EMGs M/T ratio for both groups was approximately 100% at the start of treatment for overjet improvement. In cases with no or slight lateral shift in the recorded path of closure or in the incisal region, no large differences were recorded laterally. Large EMGs differences were recorded with lateral shift in the incisal region, especially when taking the construction bite.

Activator Appliances↗
PubMed2004

Effects of increased muscle mass on mouse sagittal suture morphology and mechanics.

The purpose of this study is to test predicted form-function relationships between cranial suture complexity and masticatory muscle mass and biomechanics in a mouse model. Specifically, to test the hypothesis that increased masticatory muscle mass increases sagittal suture complexity, we measured the fractal dimension (FD), temporalis mass, and temporalis bite force in myostatin-deficient (GDF8(-/-)) mice and wild-type CD-1 mice (all male, 6 months old). Myostatin is a negative regulator of muscle mass, and myostatin-deficient mice show a marked increase in muscle mass compared to normal mice. We predicted that increased sagittal suture complexity would decrease suture stiffness. The data presented here demonstrate that increased suture complexity (measured as FD) was observed in a hypermuscular mouse model (GDF8(-/-)) with significantly increased temporalis muscle mass and bite forces. Hypermuscular mice were also found to possess suture connective tissue that was less stiff (i.e., underwent more displacement before failure occurred) when loaded in tension. By decreasing stiffness, suture complexity apparently helps to dissipate mechanical loads within the cranium that are related to chewing. These results suggest that cranial suture connective tissue locally adapts to functional demands of the biomechanical suture environment. As such, cranial sutures provide a novel model for studies in connective tissue mechanotransduction.

Animals↗
PubMed1996

An animal model for maxillary reconstruction using a temporalis muscle flap.

PURPOSE: This article describes the feasibility of using the temporalis muscle flap to cover a defect after maxillectomy in cats and to evaluate the clinical healing process of this flap in the oral environment. MATERIALS AND METHODS: The material consisted of 30 cats of the Felis catus species. A standardized unilateral maxillectomy was performed and the resulting defect immediately closed with a pedicled temporalis flap. The healing of this flap was clinically assessed at determined intervals. RESULTS: Healing of the temporalis flap in the oral environment of cats progressed from an inflammatory to a proliferative phase, with eventual coverage by a smooth oral mucosa 18 to 24 weeks after surgery. CONCLUSIONS: The cat proved to be a useful model for this type of study.

Animals↗
PubMed1995

Early temporalis muscle transposition for the management of facial paralysis.

Temporalis muscle transposition is a reliable surgical technique for the reanimation of patients with long-standing facial paralysis. It is often employed when facial nerve reinnervation via crossover or cable grafting is not possible. Temporalis muscle transposition can also be used for the immediate treatment of complete facial paralysis due to insults leaving the facial nerve anatomically intact but requiring a prolonged recovery time (more than 1 year). Because temporalis muscle transposition does not interfere with neuronal regeneration, it may be employed early in the management of complete facial paralysis when recovery is predicted to be extended and incomplete. The authors report their experience with early temporalis muscle transposition in the management of facial paralysis in 56 patients with an anatomically intact facial nerve. More than 90% of these patients achieved improved symmetry at rest as well as purposeful movement at the corner of the mouth. In the last 30 patients, the temporoparietal fascial flap was simultaneously harvested and successfully used to obliterate the donor site defect. In conjunction with the immediate implantation of a gold weight in the ipsilateral upper eyelid, this approach to the early management of facial paralysis helps reduce the period of facial disability from years to weeks in a select group of patients.

Adult↗
PubMed1991

Exteroceptive silent period of temporalis muscle in menstrual headaches.

The second exteroceptive silent period (ES2) of temporalis muscle was recorded on days 1 and 15 of the menstrual cycle in 17 women, 9 of whom suffered regularly from tension-type headaches during menstruation. Mean duration of temporalis ES2 was significantly shorter on day 1 of the cycle than on day 15. This difference was due to a marked menstrual reduction of ES2 in the headache subgroup. A positive correlation was found between ES2 durations and oestradiol/progesterone ratios. We hypothesize that the variations of ES2 during the ovarian cycle result from the modulatory effects of oestrogens on descending aminergic pathways that control excitability of inhibitory brainstem interneurons mediating exteroceptive suppression of jaw-closing motoneurons.

Adult↗
PubMed2000

Temporalis exteroceptive suppression in generalized anxiety disorder and major depression.

The duration abnormality of the exteroceptive suppressions, or silent periods, of peripheral or jaw-closing muscle activities induced by transcranial magnetic or trigeminal electrical stimuli in patients suffering from anxiety or depression is ill-defined. We therefore studied the exteroceptive suppression periods of the temporalis muscle electromyography elicited by trigeminal territory electrical stimuli, Zuckerman-Kuhlman's Personality Questionnaire, and Plutchik-van Praag's Depression Inventory (PVP) in 12 patients suffering from generalized anxiety disorder (GAD) and 16 from major depression (MD) as well as in 17 healthy volunteers. Durations of the second suppression period (ES2) sociability scores were decreased in GAD patients, while PVP and neuroticism-anxiety scores were elevated in both GAD and MD patients. There was a positive correlation between ES2 duration and sociability score in the GAD group. This study indicates that anxiety can modify the temporalis ES2 duration through cortical descending inhibitory controls.

Adolescent↗
PubMed1990

Composite temporalis pedicle flap as an interpositional graft in temporomandibular joint arthroplasty: a preliminary report.

Fifteen temporomandibular joint patients were evaluated preoperatively and postoperatively to evaluate the effectiveness of a composite (fascia, muscle and periosteum) temporalis pedicle flap as an interpositional disc replacement. A modified Craniomandibular Index (CMI) and Symptom Severity Index (SSI) were used to assess clinical and subjective symptoms. Eighteen months postoperatively there was a significant reduction in the CM and SS indices (P less than .001), with significant clinical improvement of the mandibular range of motion (P less than .05). However, a significant reduction of translation (P less than .01) was evident indicating that the increased mandibular opening was owing to a compensatory rotational movement. This study indicates that the composite temporalis pedicle flap is a good autogenous tissue for the reconstruction of the temporomandibular joint.

Adolescent↗
PubMed2003

Management of neurotropic low-grade B-cell lymphoma: report of two cases.

BACKGROUND: Low-grade lymphomas do not commonly involve the central or peripheral nervous system. METHODS: Case report and review of the literature of two cases of B-cell lymphoma of the extranodal marginal zone type involving the head and neck region with evidence of extensive neurotropism are detailed in this report. RESULTS: One patient was initially seen with a mass in the temporalis muscle and the other with a masticator space mass. The clinical course was indolent in both cases, although associated imaging studies suggested a more aggressive tumor. Both patients were treated with moderate-dose radiotherapy only. At the time of writing, one patient has no evidence of disease 6.5 years after treatment and the other at 6 months. CONCLUSIONS: This suggests that some marginal zone lymphomas exhibit a low-grade clinical course despite an aggressive radiographic pattern of perineural and neurotropic spread. This type of lymphoma might be effectively treated with moderate-dose radiotherapy.

Aged↗
PubMed1997

Temporalis muscle transfer in the correction of lagophthalmos due to leprosy.

In the correction of lagophthalmos due to leprosy neuritis temporalis muscle transfer (TMT) is used to provide a motor to assist in lid closure. This study of TMT in 51 eyes was carried out to assess the effectiveness of TMT in achieving lid closure and corneal protection. The average lid gap preoperatively on light closure was 7.3 mm which was reduced to 3.2 mm on final follow-up. The average lid gap pre-operatively on tight closure was 5.3 mm which was reduced to 0.4 mm at final follow-up. It is possible to train patients with partial or total anesthesia of the cornea in a visual THINK-BLINK reflex. The common complications encountered were ectropion in 6 eyes (12%) and ptosis in 3 eyes (6%).

Adolescent↗
PubMed2002

Lipopolysaccharide preconditioning and cross-tolerance: the induction of protective mechanisms for rat intestinal ileus.

BACKGROUND & AIMS: Endotoxin elicits an inflammatory response within the intestinal muscularis and causes intestinal muscle dysfunction. Our aims were to investigate intestinal muscle recovery after a single or repeated lipopolysaccharide (LPS) injections. We also investigated the ability of LPS to induce cross-tolerance to postoperative ileus. METHODS: Motility was measured in vivo and in vitro by transit and organ-bath techniques. Nuclear factor kappa-B, nuclear factor interleukin 6, and signal transducer and activator of transcription were quantified by using electrophoretic mobility shift assay, and tumor necrosis factor alpha, interleukin 6, inducible nitric oxide synthase, and cyclooxygenase 2 were measured with reverse-transcription polymerase chain reaction. Myeloperoxidase histochemistry for neutrophils was performed in jejunal muscularis whole mounts. RESULTS: Endotoxin-induced suppression of in vitro muscle contractility temporally recovered over 7 days with a similar profile whether after a single dose or during the continuous daily injection of LPS. Functional adaptation to continuous LPS was reflected in a significant blunting of transcription factor activation and cytokine messenger RNA up-regulation compared with the naive LPS-stimulated muscularis. Preconditioning of the muscularis showed significant cross-tolerance to the functional, molecular, and leukocytic sequelae of intestinal manipulation. CONCLUSIONS: The muscularis externa recovered and developed tolerance to endotoxin over 7 days, which conferred cross-tolerance to intestinal manipulation. Thus, preconditioning induces protective mechanisms to a subsequent insult within the muscularis externa.

Animals↗
PubMed1998

Dissociation between electrical and mechanical responses to nitrergic stimulation in the canine gastric fundus.

1. We examined the relationships between membrane potential, intracellular [Ca2+] ([Ca2+]i), and tension in muscles of the canine gastric fundus in response to nitrergic stimulation by NO donors and electrical field stimulation (EFS) of intrinsic enteric inhibitory neurons when adrenergic and cholinergic responses were blocked. 2. NO donors reduced [Ca2+]i and tension in a concentration-dependent manner. A close relationship was noted between these parameters. 3. In terms of the [Ca2+] vs. force relationship, relaxation responses to EFS differed from responses to NO donors. EFS resulted in smaller decreases in [Ca2+]i to produce a given relaxation compared with responses to NO donors. Thus, muscles stimulated with EFS were less sensitive to [Ca2+]i than muscles stimulated with exogenous NO. 4. When membrane potential, [Ca2+]i and tension were monitored simultaneously in the same muscles, a temporal dissociation was noted between the electrical responses and changes in [Ca2+]i and tension. Brief electrical responses were associated with more sustained changes in [Ca2+]i and tension. 5. Further dissociation between electrical and mechanical effects was noted. Changes in [Ca2+]i and tension caused by sodium nitroprusside and EFS were blocked by arginine analogues and by oxyhaemoglobin, but electrical responses were unaffected. 1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase, also blocked the effects of nitrergic stimulation on [Ca2+]i and tension, without affecting hyperpolarization. Thus, in the presence of continued hyperpolarization, the reductions in [Ca2+]i and tension caused by nitrergic stimulation were blocked. 6. Block of hyperpolarization in response to nitrergic stimulation with tetrapentylammonium chloride (TPEA) had relatively little effect on the [Ca2+]i and tension responses. Thus, hyperpolarization is not required for nitrergic effects on [Ca2+]i and tension. 7. In summary, reduction in [Ca2+]i and tension in response to nitrergic stimulation of the canine gastric fundus does not depend upon electrical hyperpolarization. Non-electrical mechanisms such as enhanced uptake of Ca2+ by the sarcoplasmic reticulum or reduction in the Ca2+ sensitivity of the contractile apparatus may be the primary mechanisms mediating nitrergic responses in these muscles.

Animals↗
PubMed2004

The inverted temporalis muscle flap for intraoral reconstruction: its rationale and the results of its application.

PURPOSE: The purpose of this article was to show the discrepancies among the different parts of the temporalis muscle flap (TMF), to introduce a new rotational arc for the TMF based on these findings, and to examine the outcomes associated with the use of this modified method. MATERIALS AND METHODS: Two models were established on 5 human skulls to mimic the situations with the usual dissection technique or the extended dissection technique for the TMF. The lengths of the anterior part, the middle part, and the posterior part of the flap were measured and analyzed for statistical significance. A new rotational arc for the TMF was introduced, in which the flap was inverted beneath the zygomatic arch, placing the temporalis fascia away from the oral side. Seventeen consecutive oral cancer cases treated with either the traditional method or the inverted method of flap transposition were reviewed and divided into 2 groups dictated by the rotational arcs of their flaps. The traditional TMF was used in 11 cases and the inverted TMF was used in 6 cases. Clinical examination and imaging studies were used for assessment of outcome, and the results from the 2 patient groups were compared. RESULTS: The middle and posterior parts of the temporalis muscle were significantly longer than the anterior part on the skull models. However, the middle and posterior parts did not differ greatly in length. The extended dissection technique increased the flap length except for the anterior part. Both flaps were successful in closing the defects in all cases and healed well. No muscle necrosis was observed. However, the patients receiving the traditional TMF developed noticeable cheek fullness in 4 instances, sialocele in 3, significant reduction of range of mouth opening in 2, and distinct velopharyngeal insufficiency in 2, whereas only 1 case in which the inverted TMF was used developed cheek fullness. CONCLUSIONS: The middle or posterior part of the temporalis flap is preferred over the anterior part for covering distant defects because of its extra length. The inverted TMF is simple and safe to apply. It can extend farther in the posterior oral cavity and has fewer complications than the traditional TMF.

Adult↗
PubMed1988

Mechanism of glyceryl trinitrate-induced vasodilation. I. Relationship between drug biotransformation, tissue cyclic GMP elevation and relaxation of rabbit aorta.

This study was conducted to test the hypothesis that biotransformation of glyceryl trinitrate (GTN) is involved in GTN-induced relaxation of vascular smooth muscle. The temporal relationship between GTN biotransformation, elevation of cyclic GMP content and vasodilation in rabbit aortic strips (RAS) was determined. Isolated RAS were contracted submaximally with phenylephrine, and then were incubated with 0.62 microM [3H]GTN in a 30-sec time course study. GTN-induced relaxation (inhibition of phenylephrine-induced tone) of RAS was monitored; tissue cyclic GMP content was measured by radioimmunoassay; and GTN, glyceryl-1,2-dinitrate (1,2-GDN) and glyceryl-1,3-dinitrate (1,3-GDN) concentrations in RAS were measured by thin-layer chromatography and liquid scintillation spectrometry. There was time-dependent biotransformation of GTN to GDN by the RAS and a time-dependent increase in cyclic GMP content in the RAS. Statistically significant (P less than .05) biotransformation of GTN and elevation of cyclic GMP content in the tissue occurred at 10 sec, whereas the onset of GTN-induced relaxation of RAS occurred at 12 sec. During the tissue biotransformation of GTN, there was preferential formation of 1,2-GDN compared with 1,3-GDN, with 1,2-GDN/1,3-GDN ratio of 3.0/1 at 10 sec, 5.3/1 at 20 sec and 5.8/1 at 30 sec. The results of this study are consistent with the hypothesis that GTN is a prodrug, such that biotransformation to an active metabolite is involved in GTN-induced relaxation of vascular smooth muscle. The data also indicate that the mechanisms of GTN biotransformation and GTN-induced activation of guanylate cyclase may be related intimately.

Animals↗
PubMed1993

Treatment outcomes for temporomandibular joint reconstruction after Proplast-Teflon implant failure.

A retrospective study of 107 patients (male, n = 13; female, n = 94) with 163 joints previously treated with Proplast-Teflon (PT; Vitek, Inc, Houston, TX) implants was performed. The average time in situ for the PT was 59.8 months (range, 2 to 126 months). Average length of follow-up was 84.6 months (range, 59 to 126 months). Only 12% of joints showed no significant osseous changes radiographically. Forty-five patients (42%) continue to have in situ PT implants and 36% of them experience pain that requires medication; 25% have developed an anterior open bite and malocclusion; 9% have limited vertical opening; and 40% are asymptomatic. Temporomandibular joint (TMJ) reconstruction after PT implant failure was performed with five different autologous tissues or a total joint prosthesis. Autologous tissues used to reconstruct the TMJ and the rates of success were as follows: 1) 31% free temporalis fascia and muscle graft with and 13% without sagittal split ramus osteotomy, 2) 8% dermis, 3) 25% conchal cartilage, 4) 12% costochondral grafts, and 5) 21% sternoclavicular grafts. The success rate decreased in all autologous tissue groups as the number of TMJ surgeries performed before reconstruction increased. Ankylosis was the most common cause of failure. Results of TMJ reconstruction with a total joint prosthesis were as follows: 1) 88% functional and occlusal stability of total joint prosthesis; 2) level of pain reduction was rated as 46% good, 38% fair, and 16% poor; and 3) an average interincisal opening of 27 mm at 24 months or less, and 33 mm at 25 months and beyond.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Exteroceptive suppression of temporalis muscle activity in patients with fibromyalgia, tension-type headache, and normal controls.

Changes of the second suppressive period (ES2) of the exteroceptive suppression of the temporalis muscle activity are found in patients with chronic tension-type headache (TTH) and are suggested to reflect an abnormal endogenous pain control system. We investigated whether similar changes are found in patients with the fibromyalgia syndrome (FMS) that is also believed to result from disturbed central pain processing. The ES2 values of 27 patients with FMS were compared with those of 18 patients with TTH and 40 healthy volunteers. The duration of ES2 (+/-SD) in FMS patients was 30.6+/-7.5 ms and was not significantly different from the control group (33.1+/-7.8 ms), whereas it was significantly shortened in TTH patients (22.9+/-11.5 ms). Our results indicate that, despite similar concepts on the pathophysiology of the two chronic pain disorders, there are no comparable changes of this brain stem reflex activity in FMS.

Adult↗