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Katharina D'Herde

Publications and source records attributed to Katharina D'Herde.

13 recordsLinked to original sources
PubMed2006

Atherosclerosis in the vertebral artery: an intrinsic risk factor in the use of spinal manipulation?

The presence of atherosclerotic plaques and their influence on the vertebral artery is of clinical importance within the scope of spinal manipulation. Manipulation may stimulate the development of atherosclerotic plaques, could detach an embolus with ensuing infarction, injure the endothelium or may directly cause a dissection in the presence of atherosclerotic plaques. In order to identify the sites and frequency of atherosclerotic plaques and to determine its relation to the tortuous course of the vertebral artery, a cadaveric study was performed. The vertebral arteries of 57 human cadavers were studied. The vertebral artery was virtually divided into four segments: the pre-vertebral (V1), the vertebral (V2), the atlanto-axial (V3), and the intracranial segment (V4). Abnormalities in the origin and course of the vertebral artery were noted, along with any associated osseous, or cartilaginous anomalies in the neck. After dissection, the artery was opened and macroscopically screened for the presence of atherosclerotic plaques. In 22.8% of the cases, no atherosclerotic plaques were present. In 35.1% of the cases, the atherosclerotic plaques were unilateral, of which 60.0% was on the left side, 40.0% on the right side, and in 42.1%, the occurrence was bilateral. Atherosclerotic plaques were significantly more present in the V3 segment than in the V1 (0.007) and V2 segment (0.049). In the V1 (P=0.008) and V2 segment (P=0.002), there was a correlation between a tortuous course of the vessel and the occurrence of atherosclerotic plaques. In individuals with marked atherosclerotic disease, stretching and compression effects of rotational manipulative techniques on atherosclerotic vessels impose a further risk factor for vertebrobasilar insufficiency. As direct evidence of atherosclerotic plaques are rarely available, therapists should avoid manipulative techniques at all levels of the cervical spine in the presence of any indirect sign of atherosclerotic disease or in the presence of calcified arterial walls or tortuosities of the vessels visible on routinely available X-ray images of the cervical or thoracic spine. It is strongly recommended, that if any doubt exists about the nature of a clinical presentation, vigorous manual procedures should be avoided until either the diagnosis is definitive or gentle manual therapy has proven effective.

Age Factors↗
PubMed2006

Clearance of apoptotic and necrotic cells and its immunological consequences.

The ultimate and most favorable fate of almost all dying cells is engulfment by neighboring or specialized cells. Efficient clearance of cells undergoing apoptotic death is crucial for normal tissue homeostasis and for the modulation of immune responses. Engulfment of apoptotic cells is finely regulated by a highly redundant system of receptors and bridging molecules on phagocytic cells that detect molecules specific for dying cells. Recognition of necrotic cells by phagocytes is less well understood than recognition of apoptotic cells, but an increasing number of recent studies, which are discussed here, are highlighting its importance. New observations indicate that the interaction of macrophages with dying cells initiates internalization of the apoptotic or necrotic targets, and that internalization can be preceded by "zipper"-like and macropinocytotic mechanisms, respectively. We emphasize that clearance of dying cells is an important fundamental process serving multiple functions in the regulation of normal tissue turnover and homeostasis, and is not just simple anti- or pro-inflammatory responses. Here we review recent findings on genetic pathways participating in apoptotic cell clearance, mechanisms of internalization, and molecules involved in engulfment of apoptotic versus necrotic cells, as well as their immunological consequences and relationships to disease pathogenesis.

Animals↗
PubMed2005

Extrinsic risk factors for compromised blood flow in the vertebral artery: anatomical observations of the transverse foramina from C3 to C7.

The vertebral artery (VA) is often involved in the occurrence of complications after spinal manipulative therapy. Due to osteophytes compressing the VA anteriorly from the uncinate process or posteriorly from the facet complex, the VAs are susceptible to trauma in the transverse foramina. Such altered anatomical configurations are of major clinical significance, as spinal manipulations may result in dissection of the VA with serious consequences for the blood supply to the vertebrobasilar region. The purpose of this study is to describe numerous structural features of the third to seventh cervical vertebrae in order to contribute to the understanding of pathological conditions related to the VA. The minimal and maximal diameter of 111 transverse foramina in dry cervical vertebrae were studied. The presence of osteophytes and their influence on the VA were evaluated at the vertebral body and at the superior and inferior articular facets. The diameter of the transverse foramina increased from C3 to C6, while the transverse foramina of C7 had the smallest diameter. At all levels the mean dimensions of the left foramina were greater than those of the right side. Osteophytes from the uncinate process of C5 and C6 vertebrae were found in over 60% of dry vertebrae. Osteophytes from the zygapophyseal joints were more frequent at C3 and C4 vertebrae. About half of the osteophytes of the uncinate and of the superior articular process partially covered the transverse foramina. This was less common with those of the inferior articular facets. Osteophytes covering the transverse foramen force the VAs to meander around these obstructions, causing narrowing through external compression and are potential sites of trauma to the VAs potentially even leading to dissection. We strongly advocate that screening protocols for vertebrobasilar insufficiency (VBI) be used prior to any manipulation of the cervical spine and should include not only extension and rotation but any starting position from which the planned manipulation will be performed.

Cervical Vertebrae↗
PubMed2005

Technical note: the design of a stereotactic frame for direct MRI-anatomical correlation of the brachial plexus.

The purpose of this study was to identify optimal magnetic resonance imaging (MRI) conditions to visualize discrete alterations of brachial plexus components, as part of a biomechanical study of minor nerve compression syndromes. A method was developed allowing direct comparison between the MRI image and the subsequently obtained matching anatomic section of the same specimen. We designed a stereotactic frame to obtain the precise orientation of the MRI plane with reference to the specimen and adapted a vertical band saw for multiplanar sectioning of cadaveric specimens. Two cadaveric upper quadrants were examined by MRI (TR 450 ms, TE 13 ms, pixel matrix 512 x 512 and FOV 23-26 cm) and anatomical slices were produced. One specimen was sectioned axially, while the second specimen was sectioned in an oblique plane corresponding to the natural longitudinal axis of the upper part of the brachial plexus. MR images and the corresponding slices exhibited a strong correlation. This correlation was checked by using vitamin A pearls as landmarks. MR images revealed more detail after the correlating anatomical slices were analyzed. The present study shows that the method is suited for direct MRI-anatomic comparison of the brachial plexus and is also proposed for application to other topographical regions.

Acromioclavicular Joint↗
PubMed2005

A vertebral artery without atlantic and intradural sections: a case report and a review of the literature.

This report covers a case in which the right vertebral artery (VA) did not participate in the formation of the basilar artery. The artery had an external diameter of about 1 mm. It ran trough the transverse foramina of C6 through C2, then turned backward and entered the spinal canal and the dural envelope between the posterior arch of C1 and the lamina of C2 as a medullary artery to end in the spinal arteries. The basilar artery was a continuation of the left VA only. Only very few cases of non-union of the VA with the basilar artery have been previously described. Cases with extreme reduction of one of the VAs are not exceptional. This variant is clinically important. On arteriography, this extremely rare condition could easily be misdiagnosed as an obstruction. In view of manipulative therapy and in the detection of vertebrobasilar insufficiency, one has to bear in mind that cases of non-union may influence the interpretation of these tests.

Basilar Artery↗
PubMed2005

A case of abnormal findings in the course of the vertebral artery associated with an ossified hyoid apparatus. A contraindication for manipulation of the cervical spine?

OBJECTIVE: To describe a case of a simultaneous occurrence of an ossified stylohyoid ligament in a 56-year-old male cadaver and anomalies of the vertebral artery, and to consider the clinical implications for manipulative therapists. INTERVENTION AND OUTCOME: Dissection showed a simultaneous occurrence of complete developmental ossification of the left hyoid apparatus, variants of the vertebral artery, and a left superior vena cava in a 56-year-old male cadaver. DISCUSSION: Developmental variants, posttraumatic and degenerative changes of the hyoid apparatus may result in variable degrees of ossification or calcification. CONCLUSION: This unusual disorder should be considered in the differential diagnosis of facial and neck pain especially within the scope of manipulation of the upper cervical spine. Cervical spine manipulation may exacerbate existing pathological conditions of the stylohyoid apparatus, thereby irritating neurovascular structures, and induce a fracture. Developmental ossification of this apparatus might be associated with anomalies in the atlantic section of the vertebral artery which make the patient more susceptible to vertebrobasilar insufficiency. We conclude that extreme care should be taken in the presence of such an ossification to avoid trauma to the stylohyoid apparatus and maybe even because of increased vertebrobasilar risk.

Cadaver↗
PubMed2004

Gap junctional communication and connexin43 expression in relation to apoptotic cell death and survival of granulosa cells.

Ovarian follicular atresia in all vertebrates is mediated via apoptosis that is initiated in the granulosa cell layer. Here we investigated the relation between connexin expression, cell coupling, and apoptosis in avian granulosa cells. Results from qualitative and quantitative immunocytochemical analysis and Western blotting of connexin43 (Cx43) and electron microscopic observations of gap junctions were compared with functional data on gap junctional coupling obtained by fluorescence recovery after photobleaching in four experimental groups: a control group of freshly isolated granulosa cells, 24-hr serum-free cultures as the apoptosis-inducing condition, and two other groups in which apoptosis was inhibited by either hormone substitution or exposure to elevated extracellular calcium. Our work shows that apoptosis induction in granulosa cells is accompanied by an increased level of cell coupling and that decreasing cell coupling with the gap junction blocker alpha-glycyrrhetinic acid dose-dependently inhibits apoptosis. The level of Cx43 expression was inversely related to the apoptotic index, suggesting that Cx43 expression plays a role in granulosa cell survival. Our study supports the hypothesis that gap junctional coupling plays a role in propagating a cell death message and suggests a role for Cx43 expression per se in granulosa cell survival.

Animals↗
PubMed2004

More than one way to die: methods to determine TNF-induced apoptosis and necrosis.

In most cellular systems tumor necrosis factor (TNF) induces apoptotic cell death. However, in some particular cell lines, such as the L929sA fibrosarcoma, TNF induces necrotic cell death. This effect is not the result of an inability to die apoptotically, because triggering of Fas in L929sAhFas cells leads to apoptosis. Moreover, TNFR-1-induced necrosis can be reverted to apoptosis when cells are pretreated with geldanamycin, an Hsp90 inhibitor. In contrast, addition of caspase-inhibitors (zVAD-fmk) prevents Fas-induced apoptosis and switches it to necrosis. These results demonstrate that depending on the cellular context, the same stimulus can induce either apoptosis or necrosis. Apoptosis and necrosis are clearly distinguished by their morphology, although in the absence of phagocytosis, the late stage of apoptosis is associated with secondary necrotic cell death, which is hard to distinguish from necrotic cell death. Necrosis is described mostly in negative terms as cell death that is characterized by the absence of apoptotic parameters, such as caspase activation, cytochrome c release, and DNA fragmentation. Here we describe a selection of techniques used to distinguish both modes of TNFR-1-induced cell death, namely apoptotic or necrotic cell death.

Animals↗
PubMed2003

Phagocytosis of necrotic cells by macrophages is phosphatidylserine dependent and does not induce inflammatory cytokine production.

Apoptotic cells are cleared by phagocytosis during development, homeostasis, and pathology. However, it is still unclear how necrotic cells are removed. We compared the phagocytic uptake by macrophages of variants of L929sA murine fibrosarcoma cells induced to die by tumor necrosis factor-induced necrosis or by Fas-mediated apoptosis. We show that apoptotic and necrotic cells are recognized and phagocytosed by macrophages, whereas living cells are not. In both cases, phagocytosis occurred through a phosphatidylserine-dependent mechanism, suggesting that externalization of phosphatidylserine is a general trigger for clearance by macrophages. However, uptake of apoptotic cells was more efficient both quantitatively and kinetically than phagocytosis of necrotic cells. Electron microscopy showed clear morphological differences in the mechanisms used by macrophages to engulf necrotic and apoptotic cells. Apoptotic cells were taken up as condensed membrane-bound particles of various sizes rather than as whole cells, whereas necrotic cells were internalized only as small cellular particles after loss of membrane integrity. Uptake of neither apoptotic nor necrotic L929 cells by macrophages modulated the expression of proinflammatory cytokines by the phagocytes.

Animals↗
PubMed2003

Painful isolated Horner's syndrome caused by pontine ischaemia.

PURPOSE: To alert ophthalmologists to the possibility of brainstem ischaemia in patients with isolated Horner's syndrome. DESIGN: Observational case report. METHODS: Neuro-ophthalmological and neuroimaging assessment of a 59-year-old woman presenting with an isolated Horner's syndrome after an episode of headache. RESULTS: Horner's syndrome was pharmacologically localised to a first- or second-order sympathetic neuron on the right. Magnetic resonance imaging (MRI) showed a small ischaemic lesion at the transition between pons and midbrain, lateral to the anterolateral system involving the sympathetic tract on the right side. CONCLUSION: An isolated Horner's syndrome may be the presenting sign of a brainstem infarction. This case report stresses the importance of a rational approach to Horner's syndrome and the need to order accurate MRI.

Brain Ischemia↗
PubMed2003

Mechanisms of internalization of apoptotic and necrotic L929 cells by a macrophage cell line studied by electron microscopy.

Rapid and efficient phagocytic removal of dying cells is a key feature of apoptosis. In necrotic caspase-independent modes of death, the role and extent of phagocytosis is not well documented. To address this issue, we studied at the ultrastructural level the phagocytic response to dying cells in an in vitro phagocytosis assay with a mouse macrophage cell line (Mf4/4). As target cells, murine L929sAhFas cells were induced to die by TNFR1-mediated necrosis or by Fas-mediated apoptosis. Apoptotic L929sAhFas cells are taken up by complete engulfment of apoptotic bodies as single entities forming a tight-fitting phagosome, thus resembling the "zipper"-like mechanism of internalization. In contrast, primary and secondary necrotic cells were internalized by a macropinocytotic mechanism with formation of multiple ruffles by the ingesting macrophage. Ingestion of necrotic cellular material was invariably taking place after the integrity of the cell membrane was lost and did not occur as discrete particles, in contrast to apoptotic material that is surrounded by an intact membrane. Although nuclei of necrotic cells have been observed in the vicinity of macrophages, no uptake of necrotic nuclei was observed. The present report provides a basis for future studies aimed at discovering molecular pathways that precede these diverse mechanisms of uptake.

Animals↗