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Fluctuations in neural activity during cocaine self-administration: clues provided by brain thermorecording.

Since metabolic neural activity is accompanied by heat release, measurement of local brain temperature offers a method for assessing alterations in neural activity. This approach, continuous monitoring of local brain (ventral tegmental area, ventral striatum, and hippocampus) and body (temporal muscle) temperature, was used to study intravenous cocaine self-administration in trained rats. The first self-administration of a session was preceded by a strong temperature increase that continued after the drug infusion. After peaking at the time of the second self-administration, temperature plateaued (+0.7 degrees C) with biphasic fluctuations (+/-0.10-0.15 degrees C) around each subsequent self-administration. Temperature gradually increased before and for 30-50 s after the lever-press, but then abruptly decreased to a minimum at 180-240 s, when it began to increase to reach another peak immediately after the next lever-press. Doubling the dose of injected cocaine significantly potentiated the post-cocaine temperature decrease and increased time to the next lever-press. In contrast to drug-reinforced lever-presses, temperatures phasically increased after non-reinforced lever-presses and at the end of a session when the lever was blocked and the rat was hyperactive, trying to reach the inaccessible lever. While temperature changes in each recording location were generally correlative, the initial temperature elevation was stronger in all brain structures than in muscle and ventral striatum was the structure that showed the most pronounced and consistent temperature fluctuations. These data suggest a generalized brain activation associated with cocaine-seeking and cocaine-taking behavior with its phasic fluctuations around individual drug self-injections. While the initial component of brain activation preceding the first lever-press for cocaine is internally determined and closely related to behavioral search, subsequent biphasic fluctuations in neural activity associated with repeated drug intakes appear to be drug-mediated. Cocaine-induced potentiation of monoamine transmission is a possible factor for gradual increases in neural activity that drive cocaine seeking, while a rapid, brain concentration-dependent action on Na(+) transport (local anesthetic action) is the most probable factor determining an abrupt, transient cessation of neural activation associated with cocaine reward.

Animals↗

Fluctuations in brain temperature during sexual interaction in male rats: an approach for evaluating neural activity underlying motivated behavior.

Since metabolic activity is accompanied by heat release, measurement of brain temperatures offers a method for assessing behavior-associated changes in neural activity. To explore this possibility, we monitored local brain (nucleus accumbens, medial-preoptic hypothalamus, and hippocampus) and body (temporal muscle) temperature in an experienced male rat during sexual behavior with a sexually receptive female. Placement of the female into a neighboring compartment increased the male's temperature and additional increases occurred when rats were allowed to see and partially interact with the female through a Plexiglas barrier with dime-size holes. The temperature increase was robust (1.5-2.0 degrees C), faster in all brain areas than in muscle, and peaked (38-39 degrees C) when the barrier was removed and full interaction was allowed. As the male repeatedly mounted and achieved intromission with the female, temperature further increased, peaking at ejaculation (+0.2-0.4 degrees C). Following ejaculation, the temperature abruptly dropped, until sexual interest and interaction resumed. These biphasic temperature fluctuations were generally similar in each recording location, but all brain sites (particularly, nucleus accumbens and medial-preoptic hypothalamus) showed more profound changes than the muscle. These data generally match single-unit and other physiological findings, suggesting that male sexual behavior is accompanied by sustained and generalized neural activation. This activation is triggered by sexually relevant stimuli (arousal), maintained during repeated mounts and intromissions, and peaked at ejaculation. These findings suggest brain temperature fluctuations not only as a sensitive index of functional neural activation, but as a powerful factor affecting various neural functions and an important part of brain mechanisms underlying motivated behavior.

Action Potentials↗

Surgical results of skull base surgery for the treatment of head and neck malignancies involving skull base: multi-institutional studies on 143 cases in Japan.

We analyzed 143 cases of skull base surgery collected from the eight institutions of the Study Group supported by the Grant-in-Aid for Cancer Research from the Ministry of Health and Welfare of Japan. Histologically, the most common type was squamous cell carcinoma (n = 78), which was followed by olfactory neuroblastoma (n = 16) and adenoid cystic carcinoma (n = 16). The most frequent surgical approach was frontal craniotomy (n = 66), followed by front-temporal craniotomy (n = 54) and infratemporal fossa approach (n = 8). For repair of dura matter, fascia lata was used in 37 cases. galeopericranial flap in 35 and temporal muscle fascia in 16. The 5-year survival rate by Kaplan-Meier method of nose and paranasal sinus carcinoma (n = 119) was 48%. As for histological classification, the survival rates were both 65%) in adenoid cystic carcinoma (n = 12) and bone soft tissue malignancy (n = 10), 62% in olfactory neuroblastoma (n = 16), 46% in squamous cell carcinoma (n = 62) and 33% in adenocarcinoma (n = 11). All the three cases of malignant melanoma died within 1 year, so we considered skull base surgery to be contraindicated for this disease. Complications were observed in 62 out of the 143 cases (43%); local infection was most frequent in 29 cases. liquorrhea in 18, abscess in 16, necrosis of the flap and meningitis in ten cases, DIC in four, rupture of the internal carotid artery in two and cerebral thrombosis in one. Death caused directly by surgery was in ten cases (7%). It is important that a multi-center registry be maintained to have a large enough database for comparison of results, and prognosis for each histological entity and further define the role of multidisciplinary treatment.

Adult↗

Features of a modern retrobulbar anesthetic injection for cataract surgery.

No significant complications including retrobulbar orbital hemorrhage after retrobulbar anesthetic block were identified in a retrospective review of 3,415 consecutive cataract surgical cases blocked and performed by one surgeon. The technique for retrobulbar injections using a disposable retrobulbar needle is described in detail. All injections were deliberately retrobulbar, directed toward the inferior temporal muscle cone, and were given immediately prior to cataract surgery by the surgeon.

Anesthesia, Local↗

Myositis ossificans progressiva: five generations where the disease was exclusively limited to the maxillofacial region. A case report.

Myositis ossificans progressiva is an unusual autosomal-dominant inherited disease characterized by congenital malformations and osseous metaplasia of the fascia of the muscles and connective tissue leading to ossification of the relevant area. The case report is remarkable in that eight members of the same family over five generations manifested the exclusive localization of the disease in the maxillofacial region.

Adult↗

Osteopromotive membranes enhance onlay integration and maintenance in the adult rat skull.

This study aimed to evaluate the effect of an osteopromotive membrane technique on onlay bone graft survival. Unicortical bone grafts were positioned bilaterally below the temporal muscle in 21 adult Lewis rats. In 14 rats, the bone graft on the right side was covered by an expanded polytetrafluoroethylene GORE-TEX membrane, whereas that on the left side was left uncovered. Seven rats were killed after 12 (group 1) and 20 (group 2) weeks, respectively. The remaining animals (n = 7, group 3) received membranes bilaterally, of which the right-sided membrane was removed after 12 weeks, and these animals were killed after 20 weeks. The specimens were assessed by routine histology and immunohistochemical labelling for various matrix proteins. After 12 weeks (group 1), size differences between the sides were not significant, although all control onlay bone grafts showed microscopic signs of pronounced resorption. At 20 weeks (group 2), graft integration was more complete on the membrane side. For group 3, the height was significantly more preserved on the side where the membrane was not removed. Immunolabelling demonstrated a more intense bone remodelling at the membrane sites. Membrane treatment resulted in improved graft integration and significantly greater size persistence, but complete height was not maintained.

Animals↗

Muscle attachment to the lateral aspect of the articular disk of the human temporomandibular joint.

OBJECTIVE: To investigate the anatomic attachments to the lateral aspect of the anterior band of the human temporomandibular joint articular disk. MATERIAL AND METHODS: Sixteen human cadaver half-heads were dissected and examined macroscopically. RESULTS: No direct attachment was observed between the deep masseter muscle and the temporomandibular joint articular disk. In one specimen, a small band of the anterior temporalis muscle was directly attached to the lateral aspect of the temporomandibular joint disk; whereas, on the same specimen, the attachment of the superior belly of the lateral pterygoid muscle was a comparatively large band. In another specimen, the lateral pterygoid muscle passed in an anterolateral direction. CONCLUSIONS: The masseter muscle has no functional significance in the biomechanics of temporomandibular joint disk displacement. The anterior temporalis muscle may have functional significance when it is accompanied by an anterolaterally divergent lateral pterygoid muscle.

Aged↗

Cancer patients with large defects. Reconstructional options: a case study.

We report a case of a seventy-five years old male patient with a squamous cell carcinoma (SCC) originated from the right external ear four years ago. He was undergone surgical removal of the lesion with a combination of modified neck dissection and reconstruction with the use of pectoralis major flap. Furthermore, he had radiotherapy with 6000 rads of the right temporal region. Two months ago the patient showed an extended recurrence concerning the temporal muscle and bone, the lithoid bone, the masseter and the pterygoid muscles, the right part of the mandible, the parotid gland with the facial nerve, and the superior bulb of the internal jugular vein. He had a surgical removal of the lesion in extended healthy margins and functional and esthetic reconstruction of the defect with a combination of metal fixed prosthesis of the condyle and the right mandible and the use of myocutaneous trapezius flap. This is a case report of the reconstruction options we have nowadays to provide quality of life in cancer patients.

Aged↗

Experimental toothclenching in common migraine.

The effect of 30 min voluntary toothclenching was studied in 48 patients with common migraine, randomized in two groups. Group 1 performed low-level tension at 5% and group 2, high-level tension at 30% of the individual maximum, as judged by surface EMG from the temporal muscle. Pericranial muscle tenderness was evaluated by manual palpation and a four-point verbal scale. Headache, nausea, and soreness of the chewing muscles were scored on visual analogue scales. Although surface EMG, soreness, blood pressure, heart rate and difficulty in completing the toothclenching session all showed that group 2 patients were subjected to significantly higher levels of muscle tension than group 1 patients, headache developed equally often in both groups (63%). Headache was even more pronounced in group 1 (n.s.). Five patients in group 1 and none in group 2 developed an attack of migraine during the following 24 h. Pericranial muscle tenderness was unaffected by the experimental procedure. There was no significant correlation between headache intensity and pericranial muscle tenderness. Muscle ischemia, muscle "fatigue", and strain on muscle insertions are thus unlikely to cause attacks of common migraine.

Adult↗

Positional relationships between the masticatory muscles and their innervating nerves with special reference to the lateral pterygoid and the midmedial and discotemporal muscle bundles of temporalis.

For an accurate assessment of jaw movement, it is crucial to understand the comprehensive formation of the masticatory muscles with special reference to the relationship to the disc of the temporomandibular joint. Detailed dissection was performed on 26 head halves of 14 Japanese cadavers in order to obtain precise anatomical information of the positional relationships between the masticatory muscles and the branches of the mandibular nerve. After complete removal of the bony elements, the midmedial muscle bundle in all specimens and the discotemporal muscle bundle in 6 specimens, derivatives of the temporalis, which insert into the disc were observed. On the anterior area of the articular capsule and the disc of the temporomandibular joint, the upper head of the lateral pterygoid, the midmedial muscle bundle of temporalis and the discotemporal bundle of temporalis were attached mediolaterally, and in 3 specimens the posterosuperior margin of the zygomaticomandibularis was attached to the anterolateral area of the disc. It is suggested that these muscles and muscle bundles contribute to various mandibular movements. Although various patterns of the positional relationships between the muscles and muscle bundles and the their innervating nerves are observed in the present study, relative positional relationships of the muscles and muscle bundles and of nerves of the mandibular nerve are consistent. A possible scheme of the developmental formation of the masticatory muscles based on the findings of the positional relationships between the muscles and the nerves is presented.

Female↗

Tension-type headache: pain, fatigue, tension, and EMG responses to mental activation.

Twenty patients with tension-type headache (14 chronic and 6 episodic) and 20 group-matched controls were selected for this study. They participated in a 1-hour, complex, two-choice, reaction-time test, as well as 5-minute pretest and 20-minute posttest periods. Subjects reported any pain in the forehead, temples, neck, and shoulders, as well as any feelings of fatigue and tension during the pretest, and every 10 minutes during the test and posttest by visual analog scales. Superficial electromyography was recorded simultaneously from positions representing the frontal and temporal muscles, neck (mostly splenius), and trapezius muscles. The location of pain corresponded to the position of the electrodes, but extended over a larger area. The test provoked pain in the forehead, neck, and shoulders of patients, i.e., pain scores from these regions increased significantly during the test. The pain scores continued to increase posttest. In patients, the EMG response of the trapezius (first 10 minutes of the test) was elevated relative to pretest. In controls, only the frontal muscles showed an EMG test response. Patients showed significantly higher EMG responses than controls in the neck (whole test period) and trapezius (first 10 minutes of the test period). There were significant differences in pain and fatigue scoring between patients and controls in all three periods and in tension scoring posttest. Fatigue correlated with pain, with increasing significance for all locations examined, while tension was mainly associated with the neck pain. The meaning of the variables "tension" and "fatigue" in headache, and their association with recorded muscle activity in various regions is discussed. The EMG response of the trapezius muscle to the test is discussed in comparison with similar responses observed in patients with other pain syndromes.

Adult↗

Coping strategies in episodic and chronic tension-type headache.

OBJECTIVE: To study the importance of coping with illness strategies in tension-type headache (TTH). BACKGROUND: The pathophysiology of TTH is complex, and coping with illness strategies might contribute to the transformation to a chronic form. METHODS: We examined 89 subjects (mean age, 45.6 +/- 14.8 years; range, 18 to 72 years) with episodic (n = 37) and chronic (n = 52) TTH. Patients were required to fill in a Freiburg Questionnaire of Coping with Illness (FQCI), a von Zerssen Depression Scale, quality-of-life questionnaires, and a headache home diary (over 4 weeks). In addition, pressure pain thresholds (temporal muscles) and total tenderness scores were obtained. RESULTS: Patients with chronic TTH exhibited poorer quality-of-life measures, slightly more depressive symptoms, and significantly stronger avoidance behavior and endurance strategies on FQCI scales F4 and F5 (P< .05). There was no difference between episodic and chronic TTH with respect to measures of muscle tenderness or pain thresholds. CONCLUSIONS: We conclude that disadvantageous coping with illness strategies might contribute to a transformation to chronic TTH.

Adaptation, Psychological↗

Topographic anatomy of the mandibular nerve branches distributed on the two heads of the lateral pterygoid.

The purpose of this study was to evaluate the topography of the nerve distribution on the two heads of the lateral pterygoid and to clarify their morphological-functional correlations. The nerve distribution on the lateral pterygoid was studied in 24 hemi-sectioned heads. Both heads of the lateral pterygoid were innervated from the mandibular nerve branches, but with various nerve distribution patterns. The nerves innervating the superior head of the lateral pterygoid originated from the buccal nerve only in 45.8% of cases. In contrast, the nerves innervating the inferior head of the lateral pterygoid originated from both the buccal and mandibular nerve trunk in 58.3% of cases. In the seven distribution categories of the mandibular nerve branches, both the superior and inferior heads of the lateral pterygoid had a common source of nerve innervation in only 20.8% of cases, the buccal nerve. In contrast, in 45.9% of cases, additional nerve twigs from the mandibular nerve trunk were distributed on the inferior head of the lateral pterygoid. In summary, besides the buccal nerve described in anatomy textbooks, the nerve branches that originated directly from the mandibular nerve trunk innervated the lateral pterygoid.

Aged↗

[Ophthalmo-rhinosurgical decompression operation in malignant endocrine exophthalmus].

The thyroid metabolism has to be treated first. If this is not followed by regression of the exophthalmos, treatment with prednisone over a period of several weeks is indicated. If this does not result in permanent improvement, surgical decompression of the orbit is indicated, especially if the exposition of the cornea or compression of the optic nerve represent an imminent danger. In such cases surgical decompression is preferable to multiple series of prednisone or radiation treatment (Wright 1981, Trokel 1982). Both the Krönlein-Berke operation for resection of the lateral orbital wall as well as neurosurgical resection of the orbital roof have proved to be excellent for removal of correspondingly located orbital tumors; effective decompression of the orbit in malignant endocrine exophthalmos, however, cannot be achieved this way, as the temporal muscle and the brain, respectively, prevent protrusion of the swollen orbital tissues through these apertures. Resection of the orbital floor is somewhat more effective. The mucosa of the maxillary sinus can easily be moved by the protruding orbital tissues, resulting in a reduction in the size of the maxillary sinus. This decompression, however, is effective only in the anterior two-thirds of the orbit, while the optic nerve must be relieved from the pressure of the swollen muscles in particular in the posterior one-third of the orbit. The only effective way is to remove the medical orbital wall up to the tip of the orbit. Surgical techniques for this purpose have already been recommended, but appeared unsatisfactory from a rhinological point of view.(ABSTRACT TRUNCATED AT 250 WORDS)

Graves Disease↗

Subcutaneous abdominal artificial tears pump-reservoir for severe dry eye.

PURPOSE: To assay a totally implanted pump-reservoir unit placed under the subcutaneous tissue of the abdomen for providing artificial tears to the ocular surface in patients with severe dry eye. DESIGN: Prospective non-randomized comparative (self-controlled) trial. PARTICIPANTS: Six patients with severe dry eye, in whom intermittent moistening of the ocular surface with current collyria was clinically unsatisfactory. METHODS: The six patients were treated by implanting an artificial tear pump-reservoir unit under the subcutaneous tissues of the abdomen. The reservoir is operated by a gas pump, which pumps artificial tears to the eye from a 60-ml reservoir through a silicone tube leading subcutaneously from the reservoir, via the chest, neck and lateral part of the head, and entering the conjunctival sac over the lateral canthal ligament. The catheter is anchored to the aponeurosis of the temporal muscle at the lateral rim of the orbit with a butterfly sleeve. The terminal portion of the tube runs freely along the upper conjunctival fornix, and pours 1.5 ml/day of the artificial tears into the ocular lacrimal basin with a constant flow rate. The reservoir must be refilled by percutaneous injection of artificial tears every 45 days. MAIN OUTCOME MEASURES: Schirmer test, corneal fluorescein staining, lacrimal film breakup time, lacrimal osmolarity, corneal impression cytology, best-corrected visual acuity, dryness sensation and blepharospasm before and after lacrimal reservoir implantation. RESULTS: The lacrimal subcutaneous abdominal reservoir was well tolerated with little discomfort. A delivery of 1.5 ml/day was enough to maintain a comfortable wet eye. After an average follow-up of 15 months the signs and symptoms of dry eye were dramatically improved. Four of the patients had a severe blepharospasm, which disappeared some weeks after the implantation of the lacrimal abdominal reservoir. CONCLUSION: These are the first totally implanted lacrimal reservoirs in human beings. They have proved to be a good solution for severe dry eye. At present, this method is the only one that permits a maintained wet eye surface, and the performance of corneal, conjunctival, limbal and amniotic membrane transplants in total or almost total xerophthalmia. It may also be a good solution for some of the so-called essential blepharospasms, which are frequently triggered by an underlying dry eye.

Drug Delivery Systems↗

Effect of L-arginine and NG-nitro-L-arginine on delayed neuronal death in the gerbil hippocampus.

To assess the role of nitric oxide (NO) in cerebral ischemia, we investigated the effect of L-arginine, a substrate of NO synthase (NOS), and NG-nitro-L-arginine (L-NNA), a NOS inhibitor, on neuronal death in the CA1 hippocampal region. Seventy-two Mongolian gerbils were used in the study. Both carotid arteries were occluded for 4 min to induce forebrain ischemia. Temporal muscle temperature was strictly maintained at 37.5 +/- 0.3 degrees C during the ischemia. L-arginine (10 and 100 mg kg-1) or L-NNA (1, 10 and 100 mg kg-1) was administered intraperitoneally 4 times: 30 min before, 3 h, 6 h and 24 h after induction of ischemia. Four days after ischemic insult, the animals were perfusion-fixed, and the neuronal densities in the medial, middle and lateral CA1 subfield were estimated. Average neuronal cell density of the control group was 2-3 mm in each subfield. L-arginine at doses of 10 and 100 mg kg-1 did not prevent neuronal death. L-NNA at doses of 1 and 10 mg kg-1 did not protect neuronal cells from ischemia either. However, in ischemia gerbils treated with 100 mg kg-1 L-NNA, the average neuronal cell density in the lateral CA1 subfield was 54.4 +/- 19.1, L-NNA (100 mg kg-1) significantly (p < 0.05) reduced the occurrence of neuronal death in the lateral CA1 subfield. The present results suggest that NO plays an important role in the development of neuronal injury after global ischemia.

Animals↗

Mild hypothermia on anoxic depolarization and subsequent cortical injury following transient ischemia.

Anoxic depolarization (AD) is one of the major physiological characteristics in the ischemic core. The effect of mild hypothermia on the appearance of AD and subsequent brain injury following profound ischemia is studied to evaluate the protective mechanism of hypothermia against severe ischemia. Sprague-Dawley rats were subjected to transient ischemia by hypotension (50-20 mmHg) and bilateral carotid artery occlusion (BCA-O) for 20 min in normothermia and 30 min in hypothermia. The temperature of body and temporal muscles was maintained at 37.5 degrees C and 36.5 degrees C in normothermia and 33.0 degrees C and 31.0 degrees C in hypothermia, respectively. Recording of the DC potential shift and electrocorticogram and monitoring of the cortical blood flow (CoBF) with a laser Doppler flowmeter were done epidurally on the right parietal cortex. The right parietal cortex pathology was examined 24 h after ischemia in normothermia and after 30 days in hypothermia. AD appeared in all seven normothermic rats with a fall in the CoBF to 9%-10% of the control flow. However, in spite of CoBF reduction to 8%-9% of the control flow, it did not appear in five hypothermic rats. Intra-ischemic CoBF was not statistically different between these two groups. AD appeared with the CoBF decreasing to 4%-5% of the control flow in seven hypothermic rats. Intra-ischemic CoBF in hypothermic rats exhibiting AD was significantly lower than the other two groups. The interval between BCA-O and the appearance of AD in hypothermic rats was 5.1 +/- 0.3 min (mean +/- SE), which was significantly longer than the 2.2 +/- 0.5 min observed in normothermia (p < 0.0005). Of seven normothermic rats exhibiting AD, two died within 24 h and four revealed massive neuronal injury. Of seven hypothermic rats with AD, four died between day 2 and day 13, and one revealed diffuse cerebral infarction. However, no severe ischemic injury or ischemic death was observed in all five hypothermic rats without AD. The incidence of severe neuronal injury or ischemic death was significantly lower in hypothermic rats without AD compared with normothermic rats with AD (p < 0.02) or hypothermic rats with AD (p < 0.05). Although mild hypothermia delays AD, it is suggested that raising the cerebral blood flow threshold for AD appearance has a key role in the hypothermic protection of a severely ischemic area such as the ischemic core.

Animals↗