Fluorescently-labeled fremanezumab is distributed to sensory and autonomic ganglia and the dura but not to the brain of rats with uncompromised blood brain barrier.

BACKGROUND: The presence of calcitonin gene-related peptide and its receptors in multiple brain areas and peripheral tissues previously implicated in migraine initiation and its many associated symptoms raises the possibility that humanized monoclonal anti-calcitonin gene-related peptide antibodies (CGRP-mAbs) can prevent migraine by modulating neuronal behavior inside and outside the brain. Critical to our ability to conduct a fair discussion over the mechanisms of action of CGRP-mAbs in migraine prevention is data generation that determines which of the many possible peripheral and central sites are accessible to these antibodies - a question raised frequently due to their large size. MATERIAL AND METHODS: Rats with uncompromised and compromised blood-brain barrier (BBB) were injected with Alexa Fluor 594-conjugated fremanezumab (Frema594), sacrificed 4 h or 7 d later, and relevant tissues were examined for the presence of Frema594. RESULTS: In rats with uncompromised BBB, Frema594 was similarly observed at 4 h and 7 d in the dura, dural blood vessels, trigeminal ganglion, C2 dorsal root ganglion, the parasympathetic sphenopalatine ganglion and the sympathetic superior cervical ganglion but not in the spinal trigeminal nucleus, thalamus, hypothalamus or cortex. In rats with compromised BBB, Frema594 was detected in the cortex (100 µm surrounding the compromised BBB site) 4 h but not 7 d after injections. DISCUSSION: Our inability to detect fluorescent (CGRP-mAbs) in the brain supports the conclusion that CGRP-mAbs prevent the headache phase of migraine by acting mostly, if not exclusively, outside the brain as the amount of CGRP-mAbs that enters the brain (if any) is too small to be physiologically meaningful.

Activation of pial and dural macrophages and dendritic cells by cortical spreading depression.

OBJECTIVE: Cortical spreading depression (CSD) has long been implicated in migraine attacks with aura. The process by which CSD, a cortical event that occurs within the blood-brain barrier (BBB), results in nociceptor activation outside the BBB is likely mediated by multiple molecules and cells. The objective of this study was to determine whether CSD activates immune cells inside the BBB (pia), outside the BBB (dura), or in both, and if so, when. METHODS: Investigating cellular events in the meninges shortly after CSD, we used in vivo two-photon imaging to identify changes in macrophages and dendritic cells (DCs) that reside in the pia, arachnoid, and dura and their anatomical relationship to TRPV1 axons. RESULTS: We found that activated meningeal macrophages retract their processes and become circular, and that activated meningeal DCs stop migrating. We found that CSD activates pial macrophages instantaneously, pial, subarachnoid, and dural DCs 6-12 minutes later, and dural macrophages 20 minutes later. Dural macrophages and DCs can appear in close proximity to TRPV1-positive axons. INTERPRETATION: The findings suggest that activation of pial macrophages may be more relevant to cases where aura and migraine begin simultaneously, that activation of dural macrophages may be more relevant to cases where headache begins 20 to 30 minutes after aura, and that activation of dural macrophages may be mediated by activation of migratory DCs in the subarachnoid space and dura. The anatomical relationship between TRPV1-positive meningeal nociceptors, and dural macrophages and DCs supports a role for these immune cells in the modulation of head pain. Ann Neurol 2018;83:508-521.

Anatomy and immunochemical characterization of the non-arterial peptidergic diffuse dural innervation of the rat and Rhesus monkey: Implications for functional regulation and treatment in migraine.

Objective The interplay between neuronal innervation and other cell types underlies the physiological functions of the dura mater and contributes to pathophysiological conditions such as migraine. We characterized the extensive, but understudied, non-arterial diffuse dural innervation (DDI) of the rat and Rhesus monkey. Methods We used a comprehensive integrated multi-molecular immunofluorescence labeling strategy to extensively profile the rat DDI and to a lesser extent that of the Rhesus monkey. Results The DDI was distributed across a dense, pervasive capillary network and included free nerve endings of peptidergic CGRP-expressing C fibers that were closely intertwined with noradrenergic (NA) sympathetic fibers and thin-caliber nonpeptidergic "C/Aδ" fibers. These newly identified C/Aδ fibers were unmyelinated, like C fibers, but expressed NF200, usually indicative of Aδ fibers, and uniquely co-labeled for the CGRP co-receptor, RAMP1. Slightly-larger caliber NF200-positive fibers co-labeled for myelin basic protein (MBP) and terminated as unbranched corpuscular endings. The DDI peptidergic fibers co-labeled for the lectin IB4 and expressed presumably excitatory α1-adrenergic receptors, as well as inhibitory 5HT1D receptors and the delta opioid receptor (δOR), but rarely the mu opioid receptor (µOR). Labeling for P2X3, TRPV1, TRPA1, and parasympathetic markers was not observed in the DDI. Interpretation These results suggest potential functional interactions, wherein peptidergic DDI fibers may be activated by stress-related sympathetic activity, resulting in CGRP release that could be detected in the circulation. CGRP may also activate nonpeptidergic C/Aδ fibers that are likely mechanosensitive or polymodal, leading to activation of post-synaptic pain transmission circuits. The distribution of α1-adrenergic receptors, RAMP1, and the unique expression of the δOR on CGRP-expressing DDI fibers suggest strategies for functional modulation and application to therapy.

Type I Cutaneous Meningioma (Rudimentary Meningocele) With Intradural Attachment to the Phylum Terminale.

Cutaneous meningiomas (CM) are a small subset of meningiomas, further classified into three subtypes. The authors present a 15-year-old male with a symptomatic congenital type I CM and describe the histopathological and immunohistochemical findings. To the authors' knowledge, this is the first report of an extraspinal lumbar type I CM with intradural attachment to the phylum terminale.

The Impact of Age Upon Healing: Absolute Quantification of Osteogenic Genes in Calvarial Critical-Sized Defects.

BACKGROUND: The current study was performed to elucidate changes in growth factor expression over time in critical-sized calvarial defects in rats from infancy to skeletal maturity. MATERIALS AND METHODS: Critical-sized parietal defects of 5, 6, and 8 mm were created in postnatal day 6 (P6), postnatal day (P20), and postnatal day (P84) adult rats, respectively. Dura was harvested at 3, 7, or 14 days after surgery, and serial micro-computed tomography imaging was performed through 12 weeks postoperatively. Absolute quantitative polymerase chain reaction was performed for Bone Morphogenic Protein-2 (BMP-2), Fibroblast Growth Factor-2 (FGF-2), Insulin-like Growth Factor-1 (IGF-1), and Transforming Growth Factor-ß1 (TGF-ß). RESULTS: The P6 (6-d-old) rats showed the greatest difference in gene expression between the dura derived from the defect side and the dura derived from the control side, demonstrating significant differences in TGF-ß1, BMP-2, IGF-1, and FGF-2 at various time intervals. Absolute gene expression in the defect dura was highest in the P6 rats and declined with age. Significant differences were noted at limited time points in the P20 rats for TGF-ß1 and BMP-2 as well as in the P84 rats for TGF-ß1. TGF-ß1 was the only gene studied that showed significant differences at postoperative days 3, 7, and 14 in varying age groups. CONCLUSIONS: The P6 rats have a higher osteogenic potential accompanied by a more vigorous alteration in growth factor expression compared with the P20 or P84 rats. Decrease in BMP-2 and FGF-2 as well as relative increase in TGFß-1 messenger RNA were observed in healing defects. These data provide valuable insight into the mechanism of healing of critical-sized defects and may be of use to engineer factor-releasing implants to correct skull defects.

Squash Cytology of a Dural-Based High-Grade Chondrosarcoma May Mimic That of Glioblastoma in the Central Nervous System.

BACKGROUND: Intracranial chondrosarcoma is rare, and most cases occur in the skull base. Intradural chondrosarcoma is even rarer. CASE: Here, we describe a case of dural chondrosarcoma with a radiation history for nasopharyngeal carcinoma and a radical prostatectomy for prostatic cancer 15 and 8 years earlier, respectively. A 67-year-old man presented with a 3-week memory disturbance and dysarthria. Computed tomography and magnetic resonance images of the brain revealed a dural-based mass in the left temporal area. Under the impression of a glioblastoma, a resection and an intraoperative squash cytology were done. A necrotic dirty background as well as bluish-to-pinkish myxoid stroma were characteristic; the nuclei of highly pleomorphic tumor cells were hyperchromatic to vesicular with an occasional ground-glass appearance. The cytoplasm was of an eosinophilic hyalinized condensed morphology with an occasional granular appearance. Histologically, the lobulated mass was composed of hypercellular lobules of well-differentiated chondrocytes intermixed with anaplastic pleomorphic cells and diagnosed as a conventional grade III chondrosarcoma. These cells were immunoreactive for D2-40, S-100 protein and vimentin. Brain invasion was also found. CONCLUSION: Albeit rare, dural-based chondrosarcomas should be considered in the differential diagnosis for meningeal tumors, especially in the case of previous radiation therapy.

Storage and purification adaptations for the isolation of total RNA from the dura mater.

BACKGROUND: RNA extraction is a step that precedes several molecular techniques. The fibrous tissue, more specifically the dura mater, has several limitations in routine protocols, and lacks optimization protocols to overcome these problems. OBJECTIVE: To test stock reagents and purification kits, optimizing commercial kit protocols for RNA extraction from the dura mater. METHODS: Dura mater samples were obtained from eight Wistar rats and maintained in two different stabilizers. The samples were purified using four different protocols, and the RNA was evaluated for the yield and purity in NanoDrop 2000 (Thermo Scientific, Wilmington, DE, United States). Beta-actin gene was used for analyzing gene expression, since is one of the most used reference genes. RESULTS: The RNA preservation was similar in both stabilizers. The addition of an incubation step prior the purification protocols allowed better tissue digestion and RNA recovery. The RNA purified using the protocols membrane-based showed higher quality than liquid-liquid purification. This impact was observed in the 3-week evaluation using RT-qPCR. CONCLUSION: Stabilizers are efficient for RNA preservation and membrane-based purification protocols are more suitable for RNA recovery from dura mater tissue, allowing the evaluation of gene expression in this type of tissue. Adaptations in the dura mater RNA extraction protocol differ from the pre-established protocols because it takes into account the peculiarity of fibrous tissue and low cellularity. In addition to providing a low-cost mechanism, based on techniques that are part of the laboratory routine, it is possible to improve the quality of the extracted material, ensuring greater efficiency in the use of subsequent techniques.

ANTECEDENTES: A extração de RNA é uma etapa que antecede várias técnicas moleculares. O tecido fibroso, mais especificamente a dura-máter, apresenta várias limitações nos protocolos de rotina e carece de protocolos de otimização para superar estes problemas. OBJETIVO: Testar reagentes de estoque e kits de purificação, otimizando protocolos de kits comerciais para extração de RNA da dura-máter. MéTODOS: Amostras de dura-máter foram obtidas de oito ratos Wistar e mantidas em dois estabilizadores diferentes. As amostras foram purificadas em quatro protocolos diferentes e o RNA foi avaliado quanto ao rendimento e pureza no NanoDrop 2000 (Thermo Scientific, Wilmington, DE, United States). O gene da beta-actina foi utilizado para analisar a expressão gênica, uma vez que é um dos genes de referência mais utilizados. RESULTADOS: A preservação do RNA foi semelhante em ambos os estabilizadores. A adição de uma etapa de incubação antes dos protocolos de purificação permitiu uma melhor digestão do tecido e recuperação de RNA. O RNA purificado pelos protocolos baseados em membrana apresentou qualidade superior ao da purificação líquido-líquido. Este impacto foi observado na avaliação de três semanas usando RT-qPCR. CONCLUSãO: Os estabilizadores são eficientes para preservação do RNA e os protocolos de purificação baseados em membrana são mais adequados para recuperação de RNA do tecido da dura-máter, permitindo a avaliação da expressão gênica neste tipo de tecido. As adaptações no protocolo de extração de RNA da dura-máter diferem dos protocolos preestabelecidos porque leva em consideração a peculiaridade do tecido fibroso e com baixa celularidade. Além de fornecer um mecanismo de baixo custo, baseado em técnicas que fazem parte da rotina laboratorial, é possível melhorar a qualidade do material extraído, garantindo maior eficácia no uso de técnicas subsequentes.

Use of a collagen biomatrix (TissuDura) for dura repair: a long-term neuroradiological and neuropathological evaluation.

PURPOSE: The aim of this study was to evaluate the clinical, neuroradiological, and neuropathological outcomes of patients treated with equine collagen foil (TissuDura) as a dura mater substitute during cranial and spinal neurosurgical procedures. MATERIALS AND METHODS: All patients treated at the Department of Neurosurgery of the Second University of Naples with TissuDura between 2005 and 2009 were included. Dural reconstruction was performed using TissuDura, overlaid 1 cm over the dural defect with additional fixation using fibrin glue. No surgical sutures were used. Patients underwent postoperative contrast-enhanced magnetic resonance scans at 1 week, 1 month, and 1 year after surgery to detect any cerebrospinal fluid (CSF) leaks, infections, inflammations, or CSF circulation in the surgical region. RESULTS: Dural reconstruction was performed in 74 patients, including 50 patients with tumors, two with C2 neurinoma, two with acoustic neurinoma, six with Chiari I malformation, two with severe head injury, and 12 requiring spinal surgery. Clinical and neuroradiological findings were normal and no signs of graft rejection or CSF leaks at postoperative follow-up were observed. In two cases of atypical meningioma, re-operation of the dural reconstruction was performed after 1 year. No adherences between brain and neodura were detected, and histopathological investigations demonstrated dural regeneration. CONCLUSIONS: Following dural reconstructions with TissuDura without surgical sutures, no local toxicity or complications were observed for up to 1 year. TissuDura demonstrated elasticity, non-reactivity, and good adaptability. The overlay technique using fibrin glue was simple and fast. Future studies and longer follow-up are needed to confirm the efficacy of TissuDura.

Novel histopathological classification of meningiomas based on dural invasion.

AIMS: Histological invasion into the adjacent brain parenchyma is frequently investigated in meningioma because it is an important morphological criterion for grade II meningioma according to the 2016 WHO classification. However, few studies have focused on dural invasion of meningiomas. Herein, we propose a novel histopathological classification based on dural invasion of meningiomas. METHODS: Forty-nine cases with WHO grade I meningiomas who underwent Simpson grade I removal were collected. After the meningeal layer (ML) and periosteal layer (PL) of dura mater were visualised by Masson's trichrome stain, we evaluated the depth (to the ML and PL) and the patterns (1, expanding; 2, infiltrating) of dural invasion of meningiomas using serial paraffin sections. Invasion-associated markers, including Ki-67, matrix metalloproteinase (MMP)-1, MMP-9 and MMP-13, aquaporin 1 and Na-K-2Cl cotransporter, were quantitatively analysed by immunohistochemistry. RESULTS: Thirty-five cases (71.4%) showed the dural invasion. In 27 of these 35 cases (77.1%), dural invasion was localised in ML. Type 1 (expanding type) and type 2 (infiltrating type) invasions were observed in 23 and 12 cases, respectively. The recurrence rate in cases with type 2 invasion was significantly higher than that in cases with type 1 invasion. The percentage of MMP-1-positive tumour cells was also significantly higher in cases with dural invasion than those without, suggesting involvement of MMP-1 in dural invasion. CONCLUSIONS: We quantitatively evaluated the depth and patterns of dural invasion in meningiomas. The patterns of dural invasion were associated with meningioma recurrence.

Less Use of the Bipolar Cautery can Prevent Postlaminectomy Epidural Fibrosis: An Experimental Study in Rats.

AIM: To investigate the role of bipolar electrocautery in the occurrence of epidural fibrosis following lumbar spine laminectomy in a rat model. MATERIAL AND METHODS: Fourteen male Sprague-Dawley rats (age: 4-6 months, weight: 250-300 g) were randomly divided into two groups, a bipolar group (Group I) and a control group (Group II). Laminectomy was performed between the L1 and L3 levels. In Group I (n=7), a laminectomy was carried out and soft tissue around the spinal cord was coagulated by using a bipolar electrocautery. In the control group (n=7), only laminectomy was performed. The animals were sacrificed 4 weeks after surgery, and post-laminectomy epidural fibrosis (PLEF) was evaluated. Macropathological, qualitative and quantitative histological evaluations as well as immunohistochemical staining including transforming growth factor-ß (TGF-ß), collagen I and collagen III were performed. RESULTS: The numbers of TGF-ß positive cells staining (PCS) were 3.00 ± 0.46 for Group I and 1.00 ± 0.52 for Group II. The numbers of collagen I PCS were 2.00 ± 0.93 for Group I and 1.25 ± 0.46 for Group II. The numbers of collagen III PCS were 2.25 ± 0.76 for Group I, 1.25 ± 0.46 for Group II, and TGF-ß PCS than Group II (p≤0.05). Compared with the control group, Group I's formation of epidural fibrosis was significantly increased. CONCLUSION: Our study clearly demonstrated that the use of bipolar cauterisation is associated with increased PLEF in the experimental animal model. Thus, limiting the use of bipolar cauterisation may be effective in reducing this complication.

Radiological evaluation of Hyperostosis frontalis interna: is it of clinical importance?

Hyperostosis frontalis interna (HFI) presents irregular thickening of the frontal bone. Even though HFI is frequently seen during routine radiological imaging, it usually remains unrecorded owing to a common belief that it just represents an incidental finding or anatomical variant. Recent studies implied that HFI may be clinically relevant. Etiology of HFI is still debated, while presumptions are mainly based on altered sex steroids impact on skull bone growth. Some authors implied that frontal bone might be particularly affected by this condition due to specificity of its underlying dura. In this paper we present a 27-years old female patient with a treatment resistant headache. Head CT showed massive, irregular bony mass, with lobulated contours arising from the right frontal bone, but did not cross the fronto-parietal suture, spearing the superior sagittal sinus and skull midline. After surgery, histopathological analysis of the frontal bone sample in our patient showed thickening pattern similar to those described in micro-CT studies of HFI. Furthermore, in an attempt to test speculation of the possible role of estrogen in pathogenesis of HFI, we investigated the expression of α-estrogen receptors on dura of the frontal region. These analyses confirmed nuclear expression of estrogen on frontal region dural tissue, supporting previous speculation of the development mechanisms of HFI and contributing to a better understanding of this common condition of the frontal bone. Additionally, the presence of HFI may result in severe symptomatology, which could be misinterpreted and related to other disorders if HFI is not radiologicaly recognized and reported.

Immunohistochemical profile of neurotrophins in human cranial dura mater and meningiomas.

The immunohistochemical profile of neurotrophins and their receptors in the human cranial dura mater was studied by examining certain dural zones in specimens harvested from different regions (frontal, temporal, parietal and occipital). Dural specimens were obtained during neurosurgical operations performed in ten patients for surgical treatment of intracranial lesions (meningiomas, traumas, gliomas, vascular malformations). The dural fragments were taken from the area of the craniotomy at least 8 cm from the lesion as well as from the area in which the meningioma had its dural attachment. Immunohistochemical characterization and distribution of neurotrophins, with their receptors, were analyzed. The concrete role played by these neurotrophic factors in general regulation, vascular permeability, algic responsivity and release of locally active substances in the human dura mater is still controversial. Our study revealed a general structural alteration of dural tissue due to the invasivity of meningiomatous lesions, together with an improved expression of brain derived neurotrophic factor (BDNF) in highly proliferating neoplastic cells and an evident production of nerve growth factor (NGF) in inflammatory cells, suggesting that BDNF has a role in supporting the proliferation rate of neoplastic cells, while NGF is involved in the activation of a chronic inflammatory response in neoplastic areas.

Serotonin type 1D receptors (5HTR) are differentially distributed in nerve fibres innervating craniofacial tissues.

We tested the hypothesis that the 5HT(1D)R, the primary antinociceptive target of triptans, is differentially distributed in tissues responsible for migraine pain. The density of 5HT(1D)R was quantified in tissues obtained from adult female rats with Western blot analysis. Receptor location was assessed with immunohistochemistry. The density of 5HT(1D)R was significantly greater in tissues known to produce migraine-like pain (i.e. circle of Willis and dura) than in structures in which triptans have no antinociceptive efficacy (i.e. temporalis muscle). 5HT(1D)R-like immunoreactivity was restricted to neuronal fibres, where it colocalized with calcitonin gene-related peptide and tyrosine hydroxylase immunoreactive fibres. These results are consistent with our hypothesis that the limited therapeutic profile of triptans could reflect its differential peripheral distribution and that the antinociceptive efficacy reflects inhibition of neuropeptide release from sensory afferents. An additional site of action at sympathetic efferents is also suggested.

Comparative proteomic analysis of rat juvenile and adult dura.

BACKGROUND: It has been widely observed that infants and young children can reossify large calvarial defects when they are younger than 2 years of age; afterwards, they lose this regenerative potential. Previous studies have implicated that the dura mater serves as a key regulator of calvarial regeneration. However, the molecular mechanism of calvarial reossification remains elusive. METHODS: In order to identify the proteins that may participate in this process, we performed a proteome-wide comparison of the protein expression levels of immature and mature dura using 2D electrophoresis and MALDI-TOF mass spectrometry. The Western blotting was used to verify the results of the 2D electrophoresis/MALDI-TOF mass spectrometry. RESULTS: Eleven proteins were found to express with significant differences in the immature and the mature dura. Among them, the emergence of vimentin, tropomyosin, beta-actin and gamma-actin were further confirmed by the Western blotting analysis. CONCLUSION: The proteins and proteomic profiles provide a better understanding of the molecular mechanism of calvarial regeneration.

Malignant myoepithelioma of cranial dura.

Malignant tumors of myoepithelial origin have been increasingly recognized at a variety of sites. Herein, we describe an example of malignant myoepithelioma arising in intracranial dura. The patient is a 47-year-old woman who presented with intracranial hemorrhage and on magnetic resonance imaging was found to have an enhancing tumor. No extracranial primary tumor was identified. A gross total resection was performed. Histologically, it varied in pattern from diffuse to focally (<10%) ductular and consisted of epitheloid to spindle cells showing marked mitotic activity. Prominent infiltration of the dura was noted. Immunohistochemical stains showed convincing expression of cytokeratins (AE1/AE3 and CAM 5.2), S-100 protein, smooth muscle actin, and glial fibrillary acidic protein. Electron microscopy performed on formalin-fixed, paraffin-embedded tissue demonstrated cohesive cells with focal intermediate filament content and surface basal lamina formation at stromal interfaces. Occasional desmosomes with tonofilaments surrounded intercellular lumina containing masses of filamentous material. This example of malignant myoepithelioma is the first convincing primary salivary gland type tumor to arise in an intracranial location outside the sellar region or ear. Intracranial dura should be added to various sites at which this morphologically heterogenous tumor may arise.

Primary dura-based synovial sarcoma of the parafalcine region of brain.

Dura-based intracranial neoplasms include a wide range of primary and metastatic tumors, varying in their clinical, radiologic, morphologic, and immunophenotypic characteristics. At this anatomic location, sarcomas are rare, however, they exhibit close morphologic resemblances to meningioma. Herein we describe the third case of primary synovial sarcoma of the parafalcine region in a50-years-old female, who presented with left-sided hemiplegia. The radiologic survey revealed a 5.5cm×5.8cm contrast enhancing dura-based mass at the right parafalcine region with meningeal enhancement and edema in the surrounding areas. Morphologic evaluation exhibited a high-grade spindle cell neoplasm, with focal hemangiopericytomatous pattern. The tumor cells were diffusely immunoreactive for CD99, Bcl2, TLE-1, and vimentin. The Ki-67 proliferation index was 40%. Pancytokeratin was focally positive. Epithelial membrane antigen, progesterone receptor, CD34, S-100, and glial fibrillary acidic protein were negative. Fluorescence in situ hybridization confirmed tumor specific translocation t(X;18)(p11.2;q11.2). Hence, final diagnosis of synovial sarcoma was rendered. Primary meningeal synovial sarcoma should be considered in the differential of aggressive and high-grade dura-based tumors in view of their relative chemosensitivity and future prospect of a molecular target-based therapy. The index case highlights the importance of an extensive pathologic analysis of high-grade mesenchymal lesions of the meninges to arrive at a definitive diagnosis and differentiate such tumors from other usual dura-based tumors, which has important therapeutic and prognostic implications.

Detectability and medico-legal value of the gunshot residues in the intracorporeal channel.

The application of the histochemical stain of sodium rhodizonate to the entrance wound for the detection of the lead (Pb) residues coming from the gunshot may be affected by false positive cases due to the contamination of the environmental Pb. The aim of the Authors is to histochemically search the Pb of GSR in a region which should be more protected by the contamination: the intracorporeal channel. Two hundreds and eighteen serial histological specimens of the intracorporeal channels coming from 25 subjects (dead due to gunshots and being autopsied at the Section of Legal Medicine of the Milan University, in the years 2013-2014) were stained with the sodium rhodizonate and sodium rhodizonate in acid environment (HCl 5%), and then observed by the microscope. The sodium rhodizonate showed a positivity for the Pb residues in the intracorporeal channel, with the detection of the particles within the first 2 cm beyond the entrance wound in 6 cases over the total number of 25 (24%). Victims were characterized by common features: short-barreled weapon; contact shots or short-distance shots; involvement of regions that were not covered by clothing; preservation of the microscopic structure of organs interested by the intracorporeal channel. The searching of GSR in the intracorporeal channel, even in conditions securing a high sensitivity, could represent an important test for the discrimination between an environmental contamination of Pb and the presence of Pb residues by GSR: once confirmed the presence of GSR in the intracorporeal channel by the histochemical analysis, the diagnostic process should require the application of the SEM-EDX for the confirmation of the results. Although not yet studied, this combination could be applied to cadavers exposed to the environment, with advanced post-mortal phenomena permitting at least the suspects of the existence of gunshot wounds at the macroscopic autopsy evaluation. Indeed, in some cases, the putrefaction is so advanced that no suspect of gunshot injuries could be derived from the soft tissue.

Unusual clear cell, lymphoplasmacyte-rich, dural-based tumor with divergent differentiation: a tricky case mimicking a meningioma.

We describe an unusual case of a recurrent dural neoplasm, previously diagnosed as meningioma. Histopathologically, the tumor is characterized by aggregates of divergently differentiated clear cells embedded in an abundant lymphoplasmacyte-rich stroma, mimicking a lymphoplasmacyte-rich meningioma. This study focuses on the histologic and immunohistochemical characterization of a unique dural-based tumor and provides useful guidelines for differentiating meningioma from other uncommon dural-based neoplasms. We propose that this recurrent dural neoplasm is a distinctive entity and, therefore, enlarges the spectrum of dural-based neoplasms that enter the differential diagnosis with meningiomas. Awareness of this tumor entity could prove useful for appropriate patient management.

Effect of a nitric oxide donor on nitroxergic nerve fibers in the rat dura mater.

Nitroglycerine, given subcutaneously to rats (10 mg/kg body weight) induces increased beading of nitric oxide synthase immunoreactive (NOS-IR) nerve fibers in the supratentorial cerebral dura mater, and an apparent increase in the number of NOS-IR nerve fibers in the dural areas supplied by the anterior and middle meningeal arteries, and the sinus sagittalis superior. Structural alterations of nitroxergic axons innervating blood vessels of the dura mater support the idea that nitric oxide is involved in the induction of headache also by a primary peripheral action, a well-known side effect of coronary dilator agents.

Expression of angiogenic growth factors in dural arteriovenous fistula.

OBJECT: Although various mechanisms of the development of dural arteriovenous fistula (AVF) have been described, the exact course of its pathogenesis, including molecular processes mediating its genesis, is still unknown. Recently, the importance of sinus thrombosis and venous hypertension has been reported in experimental and clinical studies. Additionally, a role of angiogenic growth factors in the pathogenesis of vascular malformations of the central nervous system has been reported. In this study, the authors investigated the existence of sinus thrombosis in dural AVF and the expression of angiogenic growth factors (basic fibroblast growth factor [bFGF] and vascular endothelial growth factor [VEGF]) in nine patients with dural AVFs that were surgically resected. METHODS: The authors examined histological features of dural AVFs that involved the transverse/sigmoid sinus in seven patients and the superior sagittal sinus in two. Sinus thrombosis was verified angiographically in seven cases and histologically in all cases. In surgically resected specimens the angiogenic growth factors bFGF and VEGF were examined immunohistochemically in nine patients with dural AVFs, with five dural sinuses from cadavers with unrelated central nervous system diseases serving as a normal control group. The media and perivascular connective tissues of the arteries in the wall of the normal dural sinuses stained faintly for bFGF; on the other hand, the expression of VEGF was not detected. In all patients with dural AVFs, the thick wall of the dural sinus stained strongly for bFGF, mainly in the subendothelial layer and media of the strongly proliferative vessels in the sinus wall, in addition to the perivascular connective tissues. In all nine cases VEGF was expressed in the endothelium of the sinus and perivascular connective tissues. In two cases, VEGF was expressed in many capillaries proliferating in the granulation-like tissues in sinuses that were obliterated by organized thrombi. CONCLUSIONS: It is concluded that the pathogenesis of dural AVF is still unknown, but that angiogenic growth factors, which might be produced by the healing process due to sinus thrombosis, may participate in the genesis of dural AVF. Understanding the mechanism of molecular pathogenesis in the development of dural AVF might aid in the establishment of a new therapeutic strategy for this dynamic vascular disease.