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At least 73 records · Page 4Linked to original sources
PubMed1981

A study of the uniaxial mechanical properties of human dura mater preserved in glycerol.

Heart valve replacements have now been made for some years from human dura mater. While the clinical results have been encouraging there is a considerable lack of information on the mechanical properties of the dura mater and the effects of the glycerol treatment employed. This study revealed that glycerol provided an adequate preserving medium for periods of up to 12 days, with no significant changes in the mechanical properties of dura mater. A wide range in mechanical properties was observed with, for example, the tensile strength varying from 3.28 N/mm2 to 7.86 N/mm2. Although no age-related deterioration in human dura mater could be shown, the results do suggest that dura mater in excess of fifty years of age should be avoided in order to prevent the selection of poor quality material.

Adult↗
PubMed2003

Dura mater mitral and tricuspid bioprostheses: 30 years of follow-up.

PURPOSE: The dura mater bioprosthesis was developed in the Department of Cardiopneumology of the Hospital das Clínicas of the University of São Paulo Medical School in 1971. Here, we present the clinical results of the dura mater bioprosthesis over 30 years of follow-up. METHODS: We studied 70 consecutive patients who underwent mitral or tricuspid valve replacement with a dura mater bioprosthesis between January 1971 and August 1972. RESULTS: The early mortality was 10% (7 patients). The follow-up was 87% complete (9 patients were lost to follow-up). Two patients were alive and asymptomatic 30 years after valve replacement; 33 patients underwent reoperations due to valve dysfunction, and 19 died during the follow-up period. At 30 years, the actuarial survival was 49.2 +/- 8.6%; freedom from rupture, 27.0 +/- 10.2%; freedom from calcification, 78.8 +/- 8.6%; and freedom from reoperation, 18.8 +/- 7.5%. CONCLUSIONS: The dura mater bioprosthesis played an important role in the treatment of patients with mitral and tricuspid valve disease. The low rate of thromboembolism and the long period of follow-up without evidence of valve dysfunction, which occurred for several of our patients, are important characteristics of these bioprosthesis.

Adolescent↗
PubMed1993

Histological examination of the gadolinium-enhanced dura mater around meningiomas on magnetic resonance imaging.

Magnetic resonance imaging often demonstrates gadolinium (Gd) enhancement of the dura mater around meningiomas. The Gd-enhanced dura mater was histologically investigated to detect meningioma cells. Gd enhancement of the dura mater occurred in 11 (79%) of the 14 meningiomas studied, and extended as far as 35 mm from the tumor. Histological examination revealed generation of vascular-rich loose connective tissue at the surface of the dura in all five tumors examined. Some clusters of meningothelial cells were distributed in the loose connective tissue in three of the five specimens, and one cluster was obviously neoplastic. These observations suggest that clusters of meningioma cells occur in the Gd-enhanced dura mater around meningiomas.

Adolescent↗
PubMed1989

[Organizational features and morphometric characteristics of the hemomicrocirculatory bed of the human brain dura mater].

By means of silver nitrate impregnation and hematoxylin -- eosin staining the microcirculatory bed of the human brain dura mater (the second half of the mature age) has been investigated. Owing to the analysis of the morphometrical data of module organization of the hemomicrocirculatory bed, an objective quantitative characteristics of its peculiarities in various layers and areas of the dura mater is presented. In three layers of the dura mater in the fornix and skull basis area, falx cerebri and tentorium cerebelli venular links predominate. Most of all morphometrical parameters of the venular vessels increase in the internal layer of the dura mater in the skull basis area. Conditions of functioning for the human brain dura mater are reflected in its blood bed, its specificity manifesting at the microcirculatory level.

Arterioles↗
PubMed1996

[Structural analysis of the thickness of human dura mater with scanning electron microscopy].

INTRODUCTION: The only references to the thickness of the human dura mater, reporting its size at various levels, are now 50 years old. Our aim was to study its tridimensional structure with the aid of the scanning electron microscope. METHOD: The samples, which were taken 8-12 h after death from 4 human cadavers between 70 and 78 years old, were examined on 2 orthogonal planes (radial longitudinal and transversal). RESULTS: The architectural structure of the external membrane of the meninges was unusual. The dura mater is made up of elastic collagen fibers organized in successive parallel planes on the surface of the medulla. Each plane constitutes a unit which we will call a sub-laminae. The sub-laminae are found in groups of 8 to 12 that form larger units called laminae, which are between 4 and 5 microns thick. The full thickness of the dura mater at the level of the third lumbar vertebrate contains from 78 to 82 laminae which together measure 270 microns. CONCLUSION: The dura mater is made up of a large number of sublaminae that are concentrically parallel to the surface of the medulla. The fibers in general run in all directions and are oriented differently in each sub-lamina. The orientation of fibers that can be seen on the outer or epidural surface corresponds only to the fibers of the outermost lamina, which has a thickness of 78 to 82 microns. A needle that pierces the dura mater passes through some 700 to 800 sublaminae, each with its own particular distribution of fibers.

Aged↗
PubMed2000

Sensory innervation of the lumbar dura mater passing through the sympathetic trunk in rats.

STUDY DESIGN: Sensory innervation of the lumbar dura mater passing through the sympathetic trunk was investigated by neuronal tracing and immunohistochemical methods. OBJECTIVE: To assess an anatomic basis indicating that sympathetic block in the higher lumbar region is effective for patients with low back pain. SUMMARY OF BACKGROUND DATA: Low back pain is elicited by disorder or mechanical stimulation of the lumbar dura mater. Clinically, the authors often have observed patients in whom root block at the responsible level or sympathetic block at the higher level could relieve low back pain. Therefore, there may be two different sensory routes, the segmental innervation at the same level and nonsegmental fibers from higher dorsal root ganglia. METHODS: The tracers were injected into the sympathetic trunk between L3 and L4 of rats. The lumbar dorsal root ganglia and dura mater were examined, and labeled cells were measured in size and the distribution. To establish the sensory property, the materials were processed in immunohistochemistry for calcitonin gene-related peptide. RESULTS: Many small- to medium-sized neurons were retrogradely labeled L1 and L2 dorsal root ganglia after injection into the sympathetic trunk. The anterogradely labeled fibers were found in the dura mater at L4 and L5. Some of the labeled neurons and fibers were immunoreactive for calcitonin gene-related peptide. CONCLUSION: Sensory fibers from the upper lumbar ganglia innervated the lower lumbar dura mater directly. These sensory nerves may mediate low back pain and possibly interact with sympathetic nerves.

Animals↗
PubMedDate not supplied

Heterotopic neuroglial tissue in the cerebral dura mater.

The presence of heterotopic neuroglial tissue in the cerebral dura mater has not been documented. This report describes three cases of heterotopic neuroglial tissue in the parasalgittal cerebral dura mater found in a study of 257 adult brains, with an incidence of 1.2%. None were associated with developmental abnormalities of the CNS. The heterotopias were isolated and completely encased within the dura mater with no attachment to the leptomeninges. Their number varied from one to nine. They were composed primarily of astrocytes in a glial network and often stained strongly for glial fibrillary acidic protein and S-100 protein. Oligodendrocyte-like cells were noted but nerve cells, ependyma-lined canals and choroid plexus were absent. Dural neuroglial heterotopias are likely developmental malformations and may represent formes frustes of encephalocele.

Aged↗
PubMedDate not supplied

[Alloplasty of dura mater defects with identical tissue prepared and transported in formalin-containing gel media].

The storage of dura mater transplants in formalin-containing gel media which allow the entire process of preparation of the biological material to be conducted in non-sterile conditions is substantiated experimentally and clinically. A formalinized allogenous tissue of the same name transplanted in experiments and in the clinic into a defect in the dura mater undergoes active reorganisation and is replaced within a year with a newly-formed connective tissue which does not differ in architectonics from the dura mater of the recipient. When transplants of the dura mater stored in formalin-containing gel media were used in the clinic (172 operations) no complications of the type of liquorrhea, prolapse of the cerebral tissue or coarse subdural adhesions were noted. Suppuration developed in 3 patients (1.7%). The cause of the suppuration, however, was not associated with the transplant. All this makes it possible to recommend allogenous transplants of dura mater stored in formalin-containing gel media for wide use in the practice.

Animals↗
PubMed2003

Neurological devices; classification of human dura mater. Final rule.

The Food and Drug Administration (FDA) is classifying human dura mater intended to repair defects in human dura mater into class II (special controls). This action is being taken to establish sufficient regulatory control to provide reasonable assurance of the safety and effectiveness of the device. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of a guidance document entitled "Class II Special Controls Guidance Document: Human Dura Mater" that will serve as the special control for this device.

Device Approval↗
PubMed1988

The innervation of the spinal dura mater: anatomy and clinical implications.

The nerves supplying the spinal dura mater were studied in four human foetuses (16-22 weeks) with the acetylcholinesterase in toto staining method. The ventral spinal dura contains a dense, longitudinally oriented, nerve plexus, which receives its contributions from: (I) the sinuvertebral nerves, (II) the nerve plexus of the posterior longitudinal ligament, (III) the nerve plexus of radicular branches of segmental arteries. Dorsal dural nerves are much smaller in number, do not form an evident plexus and do not reach the medial region of the dorsal dura. The dorsal nerves are derived from the ventral dural plexus at the level of the "intersleeval" parts of the dura mater. The ventral dural nerves may extend up to eight segments, with a great amount of overlap between adjacent nerves. This may provide an anatomical substrate for the understanding of extrasegmentally referred dural pain. The curled bundles of nerve fibres of pathways (I) and (II) provide an adequate adaptation to displacements of the spinal dura mater during flexion and extension. Pathway (III) has not been described before. The described nerve plexuses may be of importance in elucidating the mechanisms of epidural therapies in back pain and peripheral vascular disease.

Acetylcholinesterase↗
PubMed1989

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.

Adrenergic Fibers↗
PubMed2006

Differential gene expression between juvenile and adult dura mater: a window into what genes play a role in the regeneration of membranous bone.

BACKGROUND: Although reossification of large calvarial defects is possible in children, adults lack this tissue engineering capacity. In this study, the authors compared the differences in gene expression between juvenile and adult dura mater using a mouse cDNA microarray with 42,000 unique elements. METHODS: Non-suture-associated parietal bone was harvested from 6-day-old and 60-day-old mice. The dura mater was carefully dissected from the calvarial disk and snap-frozen. RNA was extracted from pooled dura mater for microarray analysis. The 25 most differentially expressed genes were listed, as were selected bone-related genes. In addition, quantitative real-time reverse-transcriptase polymerase chain reaction confirmation of selected genes-BMP-2, BMP-4, and BMP-7; and osteopontin (OP), osteocalcin (OC), and FGFR-1-was performed. RESULTS: Juvenile dura mater expressed significantly greater amounts of BMP-2 and OP. Minimal difference in OC expression was observed between juvenile and adult dura mater. Extracellular matrix proteins (Col3a1, 5a1, 6a1, and fibronectin 1), osteoblast differentiation markers (Runx2/Cbfa1, Itm2a, and FGFR-1), and the growth factor Ptn were among other genes with greater expression in juvenile dura mater. Markers of osteoclasts (Acp5, MMP9, Ctsk) and the multiple candidate gene Ntrk2 were also expressed at higher levels in the juvenile dura mater. CONCLUSIONS: These findings suggest a more differentiated osteoprogenitor population to exist along with a greater presence of osteoclasts in the juvenile dura mater relative to adults. In addition to establishing a baseline difference in gene expression between juvenile and adult dura mater, new genes potentially critical to the regenerative potential of juvenile calvaria were identified.

Age Factors↗
PubMed1994

[The polarization microscopy characteristics of collagen in dura mater transplants].

In order to establish the polarizing microscopical characteristics of collagen in preserved dura mater transplants and in controls, a study was performed. Attempt was made for an intrpretation of velocity of collagen rehydratation by means of data of total anisotropy. The results show a faster rehydratation of collagen fibrils in control (unpreserved) dura mater. Changes in the velocity of rehydratation of collagen fibrils in lyophilized dura mater were connected with structural changes during lyophilization. The most appropriate period of time for rehydratation of lyophilized dura mater transplant was determined from the results of the polarizing microscopical study.

Analysis of Variance↗
PubMed1997

[Histological study of operated cases of chronic subdural hematoma in adults: relationship between dura mater and outer membrane].

In 31 consecutive operated cases of chronic subdural hematoma (CSH) in adults, a histological study of the outer membrane and the dura mater was reported. Only 3 cases had vascular connections between the dura mater and the outer membrane. The vessels from (or to) the dura mater entered into the sinusoidal channel of the outer membrane. Dura mater always showed normal findings and was distinctly separated from the outer membrane, except for vascular connections. Because of this, they were regarded as different tissues. Hemorrhages in and out of the hematoma cavity of the outer membrane were seen in all 12 cases and seemed to be a reason for enlargement of CSH. There were 16 cases of eosinophilic infiltration in the outer membrane. No positive reaction was seen to estrogen receptor staining of either the dura mater or the outer membrane.

Adult↗
PubMedDate not supplied

[Brain injuries in relation to morphological structure of dura mater spinalis in pregnant women].

Morphological and histochemical investigations on dura mater spinalis of the lumbar site in 5 women of reproductive age dead from accidents and 5 women dead during deliveries due to hemorrhage were carried out. It was found that one of the etiological factors of head-aches after subarachnoid anesthesia was functional reduction of mechanic and supporting function of dura mater spinalis along with elasticity loss of fibrous tissue, edema and friability. The stable non-healing postpuncture defect of dura mater spinalis resulted in liquorrhea with subsequent development of the "liquorrhea hypotension" syndrome.

Accidents↗
PubMed1984

[Surgical treatment of naso-sinus tumors invading the anterior region of the base of the skull. Problems encountered during exploration, and repair of bone and dura mater].

Current limitations for surgical excision and solutions to problems of bone and dura mater repair of nasosinusal tumors invading the anterior region of the base of skull are discussed in relation to 14 cases. None of these patients had been operated upon by first intention using the upper approach Exploration of the median part of the anterior region is limited posteriorly by the posterior border of the jugum and the base of the anterior clinoid processes. Pre-operative discovery of invasion of the dura mater is a contraindication for surgery. Posterior and dural extension of the tumor is evaluated by combined CT Scan and tomography, but these examinations do not always confirm the absence of dura mater involvement before surgery. A double approach should be used when doubt as to invasion of the base exists. Dura mater repair involves suturing, a free periosteal flap, and a pediculated cranial periosteum flap anteriorly on the fronto-orbital region. Reconstruction of the base requires the use of the periosteal flap, alone or associated with bone grafts depending on the size and location of the bone breach. Short and long term postoperative complications were nor observed.

Bone Transplantation↗
PubMed1979

Lyophilised dura mater: experimental implantation and extended clinical neurosurgical use.

The historical development of dural substitutes and the process of regeneration of dura mater are reviewed. Lyophilised human cadaver dura mater has been implanted intracranially in baboons and the graft shown to be incorporated with vascularisation but with ossification. In the human, lyophilised dura mater used as a dural substitute also becomes a viable tissue but without ossification. A retrospective study of its use in 100 neurosurgical patients showed a low complication rate and it is suggested that there are occasions when the ready availability of lyophilised dura mater, without the need for a further incision, makes it the dural substitute of choice.

Animals↗