Endonasal endoscopic approach to the pterygopalatine and infratemporal fossae.

The pterygopalatine fossa and infratemporal fossa are spaces located under the skull base, housing important neurovascular structures. Surgical access to these spaces is challenging because of their deep location and complex anatomy. Their surgical access has been classically carried out through multiple craniofacial approaches until the advent of endoscopic endonasal surgery at the end of the XXth century. Our goal is to describe the transmaxillary-transsphenoidal-transpterygoid approach to the pterygopalatine and infratemporal fossae through endonasal endoscopic surgery based on anatomo-surgical dissection and an illustrative clinical case. We conclude that after careful radiologic evaluation of the feasibility of this technique, the endonasal endoscopic access to these spaces for tumor resection is efficient with reduced surgical morbidities. The endonasal approach is versatile and can be fashioned according to the nature and extent of the lesion.

Secondary structure of 11 S globulin in aqueous solution investigated by FT-IR derivative spectroscopy.

Secondary structure of 11 S globulin, a major storage protein of soybean seeds, has been investigated in aqueous solution by FT-IR spectroscopy. Conformational changes in the native protein upon thermal and chemical denaturation have been monitored by observing changes in the frequency position and peak intensity of the various bands. The frequency of the Amide I band of the native protein shifts by 4 cm-1 from 1,643 cm-1 to 1,647 cm-1 when denatured, while the corresponding intensity of the Amide I band compared to the native protein, decreases by 30 and 67%, respectively, for the urea and thermally denatured proteins, indicating gross conformational changes in the secondary structure. Trifluoroethanol, an alpha-helix promoter shifts the Amide I band from 1,643 cm-1 to 1,651 cm-1, typical of alpha-helix, with a corresponding increase in intensity by 14% relative to the native protein. Derivative spectroscopy, allowing resolution of overlapping bands, shows that the native protein mainly consists of beta-sheet, beta-turns and disordered structure with very little alpha-helix. On denaturation, beta-sheet disappeared almost completely with urea, while this is less so with thermal denaturation.

Peptidergic and serotoninergic innervation of the rat dura mater.

The peptidergic and serotoninergic innervation of the rat dura mater was investigated by reacting dural wholemounts immunohistochemically with antibodies to calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), and serotonin (5-HT). CGRP and SP innervations of the dura were robust and the patterns of distribution of these neuropeptides were essentially the same. The majority of the fibers were perivascular and distributed to branches of the anterior and middle meningeal arteries and to the superior sagittal and transverse sinuses. Other CGRP/SP fibers appeared to end "free" within the dural connective tissue. NPY-immunoreactive fibers were extremely numerous and also distributed heavily to the branches of the meningeal arteries, the venous sinuses, and to the dural connective tissue. The pattern of NPY innervation resembled in many ways that of CGRP/SP; however, NPY innervation of the sinuses was greater and NPY perivascular fibers supplying the meningeal arteries formed more intimate contacts with the walls of the vessels. The pattern of VIP innervation was, in general, similar to that observed for the three previous neuropeptides; however, the overall density was considerably less. Small to moderate numbers of serotoninergic nerve fibers were observed in some, but not all, of the duras processed for 5-HT. The latter fibers were almost exclusively perivascular in distribution. Dural mast cells were prominently stained in the 5-HT preparations because of their serotonin content. Mast cells were also labeled in a nonspecific fashion in some of the tissues reacted immunohistochemically for neuropeptides; some of them were located in close apposition to passing nerve fibers. This study represents, to our knowledge, the first comprehensive work on the peptidergic and serotoninergic innervation of the mammalian dura mater. The results should increase our understanding of the roles that these fibers play in normal dural physiology and of their potential interactions in the pathogenesis of vascular headache.

Sympathetic innervation of the supratentorial dura mater of the rat.

The origin, density, and distribution of sympathetic nerve fibers in the supratentorial dura mater of the rat were examined in detail in the current study by using wheat germ agglutinin horseradish peroxidase (WGA-HRP) retrograde tracing procedures, glyoxylic acid-induced fluorescence, and dopamine beta-hydroxylase (DBH) immunocytochemical staining of dural whole mount preparations. Application of WGA-HRP to the superior sagittal sinus and adjacent areas of the supratentorial dura mater labeled numerous neurons in each of the left and right superior cervical ganglia. Glyoxylic acid and DBH immunocytochemical staining of fixed dural whole mount preparations revealed prominent plexuses of sympathetic nerves about the middle meningeal artery and its branches, about the superior sagittal and transverse sinuses, and "free" within the dura mater, i.e., apparently unassociated with any vasculature. Significantly, in all of these areas, the density of sympathetic innervation revealed in this study was considerably greater than that previously demonstrated by other workers. An impressive population of mast cells also was observed within the dura mater of the glyoxylic acid-treated preparations. The majority of these cells were perivascular; however, a significant number were also present within the dura unrelated to the vasculature, and occasional cells were seen in close apposition to fluorescent sympathetic nerve fibers. Taken together, the identification of a robust sympathetic plexus and prominent mast cell population associated with a dura mater that also receives significant sensory projections from the trigeminal system raises interest regarding the functional interactions of these elements. These observations warrant further consideration regarding their role in the pathogenesis of vascular headache and head pain.

Nitric oxide synthase immunoreactivity in the rat dura mater.

The dura mater has been implicated as a tissue where vascular headache develops. Identification of the neural components of this tissue is a prerequisite for understanding the mechanisms of this pathological process. The nitric oxide molecule, a potent vasodilator, may contribute to the vascular headache process by dilating dural vasculature. Our immunohistochemical study using nitric oxide synthase (NOS) antibodies revealed NOS-positive nerve fibers and a prominent mast cell population in the rat dura. A majority of the immunopositive fibers were associated with the anterior meningeal artery and its branches and sparse innervation with the middle meningeal artery, its branches, and superior sagittal sinus. We propose that the NOS-positive nerve fibers and mast cells be considered as possible participants in the pathogenesis of vascular headache.

Connections of the subthalamic nucleus in the monkey.

Attempts were made to determine the afferent and efferent connections of the subthalamic nucleus (STN) in the monkey using retrograde and anterograde axoplasmic transport technics. Following HRP injections limited to the STN, label was transported to arrays of cells adjacent, and parallel, to the lateral medullary lamina in the rostral two thirds of the lateral pallidal segment (LPS). Only sparse label was transported to cells of the pedunculopontine nucleus (PPN) and the locus ceruleus (LC). No enzyme was transported across the midline, or to the striatum, medial pallidal segment (MPS), thalamus, substantia nigra (SN) or dorsal nucleus of the raphe (DNR). HRP injected into portions of both the STN and SN produced retrograde transport of the enzyme to cells in parallel arrays in the LPS related rostrocaudally to the injection site. Additional enzyme transport was seen in cells of the striatum, the DNR and the PPN. Only a few isolated cells were labeled in the sensorimotor cortex. Efferent connections of the STN were studied in monkeys in which [3H]amino acids were injected hydraulically or iontophoretically into the STN. Isotope traced in serial autoradiographs was distributed to: (1) both segments of the globus pallidus (GP) in arrays parallel to the medullary laminae, and (2) the pars reticulata of SN (SNpr). The greatest number of terminals was found in the MPS. Fibers from the rostral part of the STN descended along the dorsal border of the SN and projected ventrally to terminations in the SNpr. No isotope was transported across the midline, or to the striatum, thalamus, DNR or PPN. Isotope injected into both the STN and SN produced similar transport to the GP and transport via nigral efferent fibers to: (1) portions of the striatum, (2) specific thalamic nuclei (VAmc, VLm, DMpl), (3) deep and middle gray layers of the superior colliculus and (4) PPN. Control studies indicated that [3H]amino acids injected only into the SN were transported to PPN. HRP injected into PPN produced profuse retrograde transport in cells of the MPS and SNpr and distinct label in a few cells of the zona incerta and STN. These data suggest that the STN receives its major subcortical input from cell of the LPS arranged in arrays which have a rostrocaudal organization. No cells of the MPS or SN project to the STN. The output of the STN is to both segments of the GP and SNpr. Major subcortical projections to PPN arise from the MPS and SNpr, but afferents also arise from other sources. The major projection of PPN is to SN.

Identification of motoneurons innervating the tensor tympani and tensor veli palatini muscles in the cat.

The somatotopic arrangement of the motoneurons associated with the two non-masticatory muscles innervated by the trigeminal motor nerve, tensor tympani (TT) and tensor veli palatini (TVP), was determined in the cat using retrograde transport of horseradish peroxidase. The motoneurons of the TT are distinct and separate, ventral and ventral-lateral to the rostral two-thirds of the trigeminal motor nucleus. The cells are smaller than those of the motor nucleus and constitute a parvocellular division. Based on functional and morphological criteria, TT motoneurons may be considered as an accessory trigeminal nucleus. The somatotopic arrangement of TVP motoneurons has been described for the first time. These motoneurons are located in the rostral two-thirds of the ventromedial division of the cat trigeminal motor nucleus. The location of motoneurons associated with TT and TVP does not fit the parcellation of the cat trigeminal motor nucleus as described by previous investigators. The motoneurons of these muscles can now be assigned to areas either within (TVP) or adjacent to (TT) the rostral two-thirds of the motor nucleus.

Origin of fibers innervating the basilar artery of the cat.

The afferent and efferent projections of the cat basilar artery were examined using retrograde axoplasmic transport techniques. Following application of horseradish peroxidase (HRP) or wheat germ agglutinin-HRP (WGA-HRP) to the vessel wall, retrogradely labeled cells were observed in trigeminal, superior vagal, superior cervical, stellate and pterygopalatine ganglia. WGA-HRP injected into the pterygopalatine ganglion was retrogradely transported to cells of the reticular formation previously described as the superior salivatory nucleus. These results are discussed in relation to recent physiological data demonstrating neural involvement in the control of cerebral blood flow and vascular headache.

Central brainstem projections of the superior vagal ganglion of the cat.

The central projections of the cat superior vagal (jugular) ganglion (SVG) cells were determined using anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). WGA-HRP was injected into the SVG of 5 cats, 3 of which had the vagal nerve sectioned distal to the jugular ganglion several days previously. Following 72 h, the animals were sacrificed and the brainstem and rostral cervical spinal cord sectioned and processed with tetramethylbenzidine (TMB) and examined for anterograde transport. The vagal root afferent fibers entered the brainstem at the level of the caudal facial motor nucleus and bifurcated into descending tracts. Terminal label was identified in: the dorsal lateral subnucleus of the nucleus tractus solitarius (NTS); nucleus interpolaris and nucleus caudalis of spinal V; the ventrolateral aspect of the cuneate nucleus and; the superficial laminae (I, II) of the rostral C1-dorsal horn. To our knowledge this is the first report describing central vagal afferent terminations following injection of current axonal tract tracing substances into the isolated superior vagal ganglion. The projection of jugular ganglion cells to a region of the NTS associated with cardiovascular function is of particular interest, and may be related to ganglion cells known to innervate the cerebral vasculature and meninges.

Projections of cervical nerves to the rat medulla.

The central course of dorsal root ganglia (DRG) fibers from C1, C2 and C3, and particularly, their brainstem terminations were studied in rats using anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). WGA-HRP was injected into the exposed DRG, and after 3 days the animals were sacrificed and sections of spinal cord and brainstem were processed with tetramethylbenzidine and examined for anterograde transport. Labeled fiber terminals were identified in the dorsal horn and the central cervical nucleus in the spinal cord, and in the intermediate nucleus, cuneate nucleus, external cuneate nucleus and the caudal portion of the nucleus of the solitary tract (NTS) in the brainstem. The projection of primary sensory fibers to the visceral NTS is suggestive of a functional relationship between upper cervical and vagal nerve afferents. The potential association of these nerves with clinical problems of headache and other cephalgias is of interest.

The sensory representation of the dura mater in the trigeminal ganglion of the cat.

The representation of the dura mater in the trigeminal ganglion was examined in the cat using the horseradish peroxidase (HRP) method. Following craniotomy a 50% solution of HRP was applied to various areas of the cranial dura and after a survival time of 48 h the trigeminal ganglion was processed. Cells in the first division gave rise to fibers innervating the medial aspect of the anterior fossa as well as the tentorium cerebelli. Labeled cells associated with the orbital roof were located predominantly in the dorsal and intermediate layers of the second division while the middle fossa was found to be represented mainly in the more dorsal strata of the third division. Labeled cells were smaller than the average ganglion cell.

Localization of motoneurons innervating the stylopharyngeus muscle in the cat.

Recent investigations of the nucleus ambiguus (NA) have attempted to identify motoneurons associated with muscles of the larynx and pharynx. However, relatively little attention has been directed to the stylopharyngeus muscle, which is important in elevation of the pharynx in swallowing and speech. The present study was designed to identify the specific location of stylopharyngeus motoneurons within the brainstem. Horseradish peroxidase or fluorescent dye was injected into the stylopharyngeus muscle of 12 cats. Retrogradely labeled cells were located ipsilateral in the rostral NA and retrofacial nucleus. This is the first report to definitively localize stylopharyngeus motoneurons.

Serotonin (5-HT) fibers of the rat dura mater: 5-HT-positive, but not authentic serotoninergic, tryptophan hydroxylase-like fibers.

Serotonin (5-HT)-positive, but not tryptophan-5-hydroxylase (TPOH)-positive, authentic serotoninergic fibers were shown in the rat dura mater. 5-HT immunoreactive fibers in the dura are postulated to result from 5-HT uptake from circulating blood elements (e.g. platelets, mast cells) by perivascular sympathetic nerve fibers. A robust TPOH-immunoreactive mast cell population was identified in the dura; this result confirms the TPOH antibody specificity to cells known to synthesize 5-HT. While these results indicate that there are no authentic serotoninergic fibers in the dura mater, the mast cells, platelets and cerebrospinal fluid can serve as a source of 5-HT activating 5-HT receptors known to be present in this tissue.

Immunohistochemical localization of endothelial nitric oxide synthase in vessels of the dura mater of the Sprague-Dawley rat.

Nitric oxide (NO) and the dura mater are implicated in the pathogenesis of vascular headache. Many studies have demonstrated the participation of NO in headache; however, few studies have identified NO in the dura mater. In this study, nine Sprague-Dawley rats were examined with immunohistochemistry using two different endothelial nitric oxide synthase (eNOS) monoclonal antibodies, H32 and ECNOS. eNOS was successfully localized to the endothelium of the middle meningeal artery. To the best of our knowledge, this is the first study to report NOS immunopositive endothelial cells in the blood vessels of the rat dura mater. The authors propose that NO plays an active role in dural vasodilation, contributing to the pathogenesis of vascular headache; in the future, NO inhibitors could serve as pharmacological agents to treat vascular headache.

Somatotopic distribution of corneal afferent neurons in the guinea pig trigeminal ganglion.

The size and somatotopic distribution of corneal afferent neurons in the guinea pig trigeminal ganglion were determined using a retrograde axonal tracing technique. Wheat germ agglutinin-horseradish peroxidase (WGA-HRP) was applied to the central cornea of the guinea pig and the animals were perfusion-fixed 48 h later. In addition, a preliminary study examined corneal afferent neurons in two animals latently infected with the herpes simplex virus by corneal inoculation. The majority of WGA-HRP-labelled neurons were located in the ophthalmic division of the ipsilateral ganglion. A clear dorsoventral somatotopic arrangement of labelled corneal afferent neurons was noted. The size of the neurons averaged 23 microns and the number of cells per ganglion averaged 205. By contrast, the number of labelled neurons in latently infected ganglia averaged less than 50. No size or morphological distinctions could be made between neurons from uninfected or latently infected ganglia. The results of this study have provided for the first time the precise location and somata diameter of primary afferent corneal neurons within the guinea pig trigeminal ganglion.

Dural neuropeptide changes after subarachnoid hemorrhage in rats.

The effect of subarachnoid hemorrhage (SAH) on the neuropeptides and mast cells of the rat dura mater has not been reported. We examined the outcome of SAH on the rat supratentorial dura mater to determine whether dural nerves undergo effects similar to those of nerves accompanying cerebral blood vessels after SAH. Following the injection of fresh autologous arterial blood into the cisterna magna, animals were sacrificed at 6, 24, and 48 h, and 6 days post-SAH. Dural whole mounts were immunohistochemically reacted with antibodies to calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and serotonin (5-HT). SP-like immunostaining was substantially reduced after SAH and subsequently returned to control levels at 6 days. NPY-like fiber innervation of the dura was markedly reduced after SAH; although immunostaining intensity increased, it had not returned to control levels at 6 days. The 5-HT content of dural mast cells identified by immunostaining markedly decreased at 6 and 24 h and returned to control levels at 48 h. In contrast, CGRP immunostaining was unchanged in all experimental groups. One possible explanation for this differential response is that subpopulations of trigeminovascular neurons containing SP, CGRP, or CGRP and SP respond differently to various stimuli, including SAH. Another possibility is a differential release of SP or CGRP from the same fiber. To the best of our knowledge this is the first documentation that the dura is also a target for intracranial pathological processes, such as SAH.(ABSTRACT TRUNCATED AT 250 WORDS)

Innervation of the posterior fossa dura of the cat.

This study was designed to identify the location of neurons giving rise to fibers innervating the posterior fossa dura in the cat using horseradish peroxidase (HRP, Sigma, Type VI). Investigations since the 19th century have implicated innervation by cranial nerves V, VII, IX, X and XII and the upper cervical nerves, C1-3. The meninges of the posterior fossa of 14 cats was exposed using one of three surgical approaches: (1) a suboccipital craniectomy and C1 laminectomy, (2) a parieto-occipital craniectomy with removal of the occipital lobe and bony tentorium exposing the meninges over the cerebellum, or (3) an anterior approach through the upper neck, exposing the dura of the ventral surface of the caudal brainstem. A unilateral, curvilinear incision was made in the dura and HRP was applied to the exposed dural edges. Following 48 hours the animals were sacrificed and fixed by perfusion. Cranial nerve ganglia of V, VII, IX, X, dorsal root ganglia (DRG) of C1-3, and superior cervical ganglia (SCG) were removed bilaterally, sectioned and processed with tetramethylbenzidine (TMB). HRP labeled cells were located bilaterally, always more ipsilaterally, in DRG of C1, C2, C3, and SCG with application of HRP to all three regions of the dura. Labeled cells were also located in trigeminal ganglia and superior ganglia of CN X, occasionally bilaterally, depending on the site of application. No HRP was ever identified in neurons of the geniculate ganglion, inferior ganglion of CN X or superior or inferior ganglia of CN IX. This information is valuable to an understanding of the innervation of intracranial structures and the problems of head pain.

Localization of motoneurons innervating the levator veli palatini muscle in the cat.

Recent investigations of the nucleus ambiguus (NA) have attempted to identify motoneurons associated with the branchiomeric muscles of the larynx and pharynx. However, relatively little attention has been directed to the levator veli palatini muscle (LVP) which is critical in respiration, deglutition and eustachian tube function. Although the consensus is that cranial nerve X (vagus) innervates this muscle, some investigators have suggested that the LVP is innervated by either cranial nerve VII (facial) or IX (glossopharyngeal). The present study was designed to identify the specific location of LVP motoneurons within the brainstem. Horseradish peroxidase (HRP) was injected into the LVP of 18 cats. Following a survival period of 24-48 hours, animals were sacrificed and tissue processed according to Mesulam's TMB procedure. HRP labeled cells were located in the rostral NA both ipsilateral and contralateral to the side of injection and in the ipsilateral retrofacial nucleus (RFN). There were no labeled cells in the facial nucleus. Innervation of the LVP by cranial nerve VII would thus be excluded. This is the first report to definitively localize LVP motoneurons. Although the innervation of LVP by cranial nerve X is generally agreed upon in basic anatomy textbooks, identification of LVP motoneurons within the NA does not exclude innervation by cranial nerve IX.

Synovial cyst of the cervical spine.

A case of acute posttraumatic myelopathy resulting from hemorrhage into synovial cysts bilaterally at the C-6, C-7 facet joints is presented. The pathogenesis of synovial cysts remains unclear, although reports in the literature have implicated trauma leading to cyst enlargement. Hemorrhage into the cavity of the synovial cysts resulted in epidural compression of the spinal cord in this patient. Because spinal synovial cysts cannot be unequivocally diagnosed preoperatively, other more common conditions must be considered in the differential diagnosis. Radiographic analysis including plain films, computed axial tomography, and metrizamide myelography are of value in establishing a neurological diagnosis. Surgical decompression and excision of the lesion may result in significant neurological improvement.

Segments of the internal carotid artery: a new classification.

This study proposes an anatomically based nomenclature for the internal carotid artery (ICA) that can be applied by all disciplines. In 1938, Fischer published a seminal paper describing five segments of the ICA that were designated C1 through C5. These segments were based on the angiographic course of the intracranial ICA rather than its arterial branches or anatomic compartments. Subsequent attempts to apply modern nomenclature to these numerical segments failed to recognize Fischer's original intent of describing patterns of arterial displacement by tumors and, therefore, resulted in a nomenclature that was anatomically inaccurate. Fischer's system was further limited, because segments were numbered opposite the direction of blood flow and the extracranial ICA was excluded. The authors propose a new classification, which includes the entire ICA, uses a numerical scale in the direction of blood flow, and describes the segments of the ICA according to a detailed understanding of the anatomy surrounding the ICA and the compartments through which it travels. Twenty cadaveric specimens with intravascular injection of silicone rubber were used for microscopic dissection and 20 dry skulls were inspected. Histological sections in critical areas were examined. The authors' classification has the following seven segments: C1, cervical; C2, petrous; C3, lacerum; C4 cavernous; C5, clinoid; C6, ophthalmic; and C7, communicating. This classification is practical, accounts for new anatomic information and clinical interests, and clarifies all segments of the ICA.