The morphology of the anterior and posterior internal vertebral venous plexus (IVVP) in human fet... more The morphology of the anterior and posterior internal vertebral venous plexus (IVVP) in human fetuses between 21-25 weeks of gestational age is described. The results are compared to the findings of a previous morphological study of the IVVP in the aged. The morphological pattern of the anterior IVVP in the fetus is very similar with the anterior IVVP in the aged human. In contrast, the posterior IVVP in the fetus lacks the prominent transverse bridging veins that are present in the aged lower thoracic and the lumbar posterior IVVP. The background of these morphological differences is unclear. Maybe the thoracolumbar part of the posterior IVVP is subject to "developmental delay," or the observed differences in the aged may result from functional and age-related factors that trigger this part of the vertebral venous system during (erect) life. The observed age related morphological differences of the posterior IVVP support the concept of the venous origin of the spontaneous spinal epidural hematoma (SSEH).
In the literature it is generally assumed that venous reflux within the radicular veins is preven... more In the literature it is generally assumed that venous reflux within the radicular veins is prevented by the presence of bicuspid valves and narrowing of the transdural part of these vessels. Recently, we performed a human cadaver study of the internal vertebral venous plexus. Surprisingly, a large number of radicular and perimedullary veins appeared to be filled with Araldite CY 221 mixture, after injection of this material into the vertebral venous system, implicating reflux via the radicular veins and suggesting insufficiency of the presumed anti-reflux mechanism. Therefore, it was decided to study the radicular veins in order to determine and to investigate the presence or absence of anti-reflux mechanisms within this system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. After polymerization, all cadavers were dissected and the spinal nerve sheaths, including nerve roots, radicular veins and epidural veins, were excised as a whole. After macroscopical examination, serial sections (40 microm) were cut on a freezing microtome and stained in Von Gieson medium. Every third section was stained immunohistochemically with smooth muscle antigen (SMA), to visualize smooth muscle cells. In all cadavers, a number of intradural radicular veins was filled with Araldite. Employing microscopical examination, no bicuspid valves were found. However, four structures were encountered that might serve as ananti-reflux-mechanism: 1) intravenous dural folds, 2) meandrous configuration, and 3) narrowing of the radicular veins at the point of penetration of the dura mater, and 4) varying numbers of smooth muscle fibers in the walls of the intradural and extradural parts of the radicular veins. Reflux via the radicular veins seems to be a physiological phenomenon. Structural valves have not been encountered during this study. Intravenous dural folds, meandrous configuration and narrowing of the transdural part of the radicular veins, and the presence of large numbers of smooth muscle cells in the radicular venous walls suggest the existence of a dynamic reflux-regulating system that has the ability to increase the intravascular resistance under conditions of venous hyperpression, in order to protect the spinal cord from venous pressure waves. Possibly, venous reflux via the radicular veins has a role in selective cooling of the spinal cord.
In the literature it is generally assumed that venous reflux within the radicular veins is preven... more In the literature it is generally assumed that venous reflux within the radicular veins is prevented by the presence of bicuspid valves and narrowing of the transdural part of these vessels. Recently, we performed a human cadaver study of the internal vertebral venous plexus. Surprisingly, a large number of radicular and perimedullary veins appeared to be filled with Araldite CY 221 mixture, after injection of this material into the vertebral venous system, implicating reflux via the radicular veins and suggesting insufficiency of the presumed anti-reflux mechanism. Therefore, it was decided to study the radicular veins in order to determine and to investigate the presence or absence of anti-reflux mechanisms within this system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. After polymerization, all cadavers were dissected and the spinal nerve sheaths, including nerve roots, radicular veins and epidural veins, were excised as a whole. After macroscopical examination, serial sections (40 microm) were cut on a freezing microtome and stained in Von Gieson medium. Every third section was stained immunohistochemically with smooth muscle antigen (SMA), to visualize smooth muscle cells. In all cadavers, a number of intradural radicular veins was filled with Araldite. Employing microscopical examination, no bicuspid valves were found. However, four structures were encountered that might serve as ananti-reflux-mechanism: 1) intravenous dural folds, 2) meandrous configuration, and 3) narrowing of the radicular veins at the point of penetration of the dura mater, and 4) varying numbers of smooth muscle fibers in the walls of the intradural and extradural parts of the radicular veins. Reflux via the radicular veins seems to be a physiological phenomenon. Structural valves have not been encountered during this study. Intravenous dural folds, meandrous configuration and narrowing of the transdural part of the radicular veins, and the presence of large numbers of smooth muscle cells in the radicular venous walls suggest the existence of a dynamic reflux-regulating system that has the ability to increase the intravascular resistance under conditions of venous hyperpression, in order to protect the spinal cord from venous pressure waves. Possibly, venous reflux via the radicular veins has a role in selective cooling of the spinal cord.
During the last 120 years, several mechanisms to protect the spinal nerve against traction have b... more During the last 120 years, several mechanisms to protect the spinal nerve against traction have been described. All the described structures were located inside the spinal canal proximal to the intervertebral foramen. Ligaments with a comparable function just outside the intervertebral foramen are mentioned ephemerally. No studies are available about ligamentous attachments of cervical spinal nerves to adjacent vertebrae. To identify and describe ligamentous structures at each cervical level that attaches spinal nerves to structures in the extraforaminal region. An anatomical study of the extraforaminal attachments of the cervical spinal nerves was performed using human spinal columns. Five embalmed human cervical spines (C1-C8) were dissected. The extraforaminal region was dissected bilaterally to describe and measure anatomical structures and their relationships with the cervical spinal nerves. Histology was done on the ligamentous connections of nerves to the adjacent vertebral structures. The cervical spinal nerves are attached to the transverse process of the vertebrae. The connecting ligaments consist mainly of collagenous fibers. At the cervical level, direct ligamentous connections exist between extraforaminal cervical spinal nerves and nearby structures. They may serve as a protective mechanism against traction. In addition, these ligaments play an important role in the positioning of the nerves in the intervertebral foramen.
Several fluorescent tracers were injected intravenously in the tail veins of adult mice, and the ... more Several fluorescent tracers were injected intravenously in the tail veins of adult mice, and the distribution of these substances in the central nervous system and sensory and autonomic ganglia was investigated. Injections of the blue tracers Granular Blue, True Blue and Fast Blue resulted in labeling of the somatomotor and visceromotor nuclei of the brainstem and spinal cord, the paraventricular, supraoptic and arcuate nuclei of the hypothalamus, the area postrema and the sensory and sympathetic ganglia. Following i.v. injections of Nuclear Yellow, labeling occurred only in the median eminence, the area postrema and the sensory and sympathetic ganglia.
Key words." rat retina -nucleus oculomotorius -Nuclear Yellow Phaseolus vulgaris-leucoagglutinin ... more Key words." rat retina -nucleus oculomotorius -Nuclear Yellow Phaseolus vulgaris-leucoagglutinin The centrifugal projection to the eye has been studied in rats with anterograde and retrograde tracing techniques. As a retrograde tracer Nuclear Yellow (NY) was used. Following NY injections into the vitreous body of the eye, labeled neurons were exclusively found bilaterally in nucleus oculomotorius. The course and termination site of the retinopetal fibers were studied with the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). lontophoretic injections of PHA-L in nucleus oculomotorius resulted in labeling of retinopetal fibers which reach the eye via the optic tract and optic nerve. Preterminal arborizations were found in the inner nuclear layer of the retina. In addition, labeled fibers have been observed which seem to terminate within the optic tract and optic nerve. It is suggested that the projection from the nucleus oculomotorius to the retina constitutes a link in the multisynaptic efferent pathway from the visual cortex to the eye, by which the visual cortex can influence the functioning of the retina.
The mammalian vomeronasal organ (VNO) is a well-adjusted chemosensory structure that facilitates ... more The mammalian vomeronasal organ (VNO) is a well-adjusted chemosensory structure that facilitates social and reproductive behavior in mammals. The existence, locality, and function of this organ in human adults remain a matter of discussion. Most authors now agree that a neuroreceptive function of the adult human VNO can be excluded due to the absence of both neural receptive cells associated with the VNO in other mammals despite the enigmatic reports on the effects of pheromones on human behavior. Adult cadavers form European (Caucasoid) descent were used in this article and parasagittal dissection of the heads allowed access to the nasal septa, which were grossly examined for the VNO openings. Tissue samples were collected, embedded in gelatin and serially sectioned through cryomicrotomy. Nissl staining was performed as well as immunohistochemically stained with an antibody against calcium-binding protein. The findings presented here confirm the bilateral presence of the VNO in adult cadavers and demonstrate morphological connections of VNO receptor cells with the underlying capillaries. In addition, possible endocrine activity associated with the epithelium of this chemosensory structure has been demonstrated by the expression of calcium-binding protein in a part of these receptor cells.
Neuropathology and Applied Neurobiology, May 27, 2003
The presence and distribution of misrouted (MR) olfactory projection fibres were studied in the o... more The presence and distribution of misrouted (MR) olfactory projection fibres were studied in the olfactory bulbs of control human brains and in the brains of people who had suffered from Parkinson's and Alzheimer's disease. It appeared that MR fibres, that is, fibres that terminate deep into the glomerular layer, are a common phenomenon in the bulbs of aged people. In all but one of the bulbs studied, MR fibres are present. The amount of MR fibres is not related to age. With a few exceptions, the MR fibres are restricted to the external plexiform layer (EPL). Only in Parkinson bulbs the MR fibres occasionally form glomerulus‐like structures. These pseudo glomeruli are located in the EPL. It is concluded that MR olfactory projection fibres are a normal phenomenon in the human olfactory bulb. In nonhuman mammalians, MR fibres have only been observed in foetal and neonatal olfactory bulbs. Possibly, the age‐related loss of mitral cells, which are the natural synaptic targets for the olfactory projection fibres, may play a role in the aberrant behaviour of the MR olfactory receptor cell axons. The ectopic glomerulus‐like structures in Parkinson bulbs share some characteristics with normal rat glomeruli that are not observed in normal human olfactory glomeruli. This may refer to possible changes in the genetic content of olfactory structures in Parkinson patients.
The aim of the present study is to provide a complete description of the distribution of choline ... more The aim of the present study is to provide a complete description of the distribution of choline acetyltransferase (ChAT) immunoreactivity (i) in the brain of the lizard Gallotiagalloti, on the basis of two different primary antisera: rat anti-ChAT and rabbit anti-chicken C U T. Considering that the brain is a segmented structure, we have analysed our data with respect to transverse segmental domains (or neuromeres), which have been previously described by several authors in the brain of vertebrates. In the telencephalon, ChATi neurons are seen in the cortex, anterior dorsal ventricular ridge, basal ganglia, diagonal band, and bed nucleus of the stria terminalis. Further caudally, ChATi cell bodies are located in the preoptic area, hypothalamus, habenula, isthmus, and all motor efferent centers of the brainstem and spinal cord. Plexuses of ChATi fibers are observed in the areas containing cholinergic cell bodies. In addition, distinct plexuses are found in the cortex, the posterior dorsal ventricular ridge, the neuropiles of all primary visual centers of the diencephalon and mesencephalon, and several non-visual nuclei of the brainstem. The distribution of ChAT immunoreactivity in the brain of G. galloti resembles in many respects that of other vertebrates, and differences are mainly observed in the pretectum and midbrain tectum. Transverse segmental domains were identified in the brainstem and forebrain of Gallotia when the cranial nerve roots and fiber tracts were used as a reference, and most cranial motor nuclei were found to occupy the same segmental positions as have been reported in the chick.
In the present study HRP injections have been placed in various thalamic areas in order to invest... more In the present study HRP injections have been placed in various thalamic areas in order to investigate spinothalamic projections in the lizard Varanus exanthematicus. It appeared that the spinal cord projects to three different thalamic areas: nucleus dorsomedialis, nucleus ventrolateralis, and an area that includes both the nucleus dorsolateralis and nucleus intermediodorsalis. Spinal neurons projecting to nucleus dorsomedialis are localized bilaterally at the medial side of the dorsal horn. Following injections in nucleus ventrolateralis, labeled neurons were found bilaterally in area VII and VIII, whereas nucleus dorsolateralis and nucleus intermediodorsalis receive a bilateral input mainly from areas V and VI.
The morphology of the anterior and posterior internal vertebral venous plexus (IVVP) in human fet... more The morphology of the anterior and posterior internal vertebral venous plexus (IVVP) in human fetuses between 21-25 weeks of gestational age is described. The results are compared to the findings of a previous morphological study of the IVVP in the aged. The morphological pattern of the anterior IVVP in the fetus is very similar with the anterior IVVP in the aged human. In contrast, the posterior IVVP in the fetus lacks the prominent transverse bridging veins that are present in the aged lower thoracic and the lumbar posterior IVVP. The background of these morphological differences is unclear. Maybe the thoracolumbar part of the posterior IVVP is subject to "developmental delay," or the observed differences in the aged may result from functional and age-related factors that trigger this part of the vertebral venous system during (erect) life. The observed age related morphological differences of the posterior IVVP support the concept of the venous origin of the spontaneous spinal epidural hematoma (SSEH).
In the literature it is generally assumed that venous reflux within the radicular veins is preven... more In the literature it is generally assumed that venous reflux within the radicular veins is prevented by the presence of bicuspid valves and narrowing of the transdural part of these vessels. Recently, we performed a human cadaver study of the internal vertebral venous plexus. Surprisingly, a large number of radicular and perimedullary veins appeared to be filled with Araldite CY 221 mixture, after injection of this material into the vertebral venous system, implicating reflux via the radicular veins and suggesting insufficiency of the presumed anti-reflux mechanism. Therefore, it was decided to study the radicular veins in order to determine and to investigate the presence or absence of anti-reflux mechanisms within this system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. After polymerization, all cadavers were dissected and the spinal nerve sheaths, including nerve roots, radicular veins and epidural veins, were excised as a whole. After macroscopical examination, serial sections (40 microm) were cut on a freezing microtome and stained in Von Gieson medium. Every third section was stained immunohistochemically with smooth muscle antigen (SMA), to visualize smooth muscle cells. In all cadavers, a number of intradural radicular veins was filled with Araldite. Employing microscopical examination, no bicuspid valves were found. However, four structures were encountered that might serve as ananti-reflux-mechanism: 1) intravenous dural folds, 2) meandrous configuration, and 3) narrowing of the radicular veins at the point of penetration of the dura mater, and 4) varying numbers of smooth muscle fibers in the walls of the intradural and extradural parts of the radicular veins. Reflux via the radicular veins seems to be a physiological phenomenon. Structural valves have not been encountered during this study. Intravenous dural folds, meandrous configuration and narrowing of the transdural part of the radicular veins, and the presence of large numbers of smooth muscle cells in the radicular venous walls suggest the existence of a dynamic reflux-regulating system that has the ability to increase the intravascular resistance under conditions of venous hyperpression, in order to protect the spinal cord from venous pressure waves. Possibly, venous reflux via the radicular veins has a role in selective cooling of the spinal cord.
In the literature it is generally assumed that venous reflux within the radicular veins is preven... more In the literature it is generally assumed that venous reflux within the radicular veins is prevented by the presence of bicuspid valves and narrowing of the transdural part of these vessels. Recently, we performed a human cadaver study of the internal vertebral venous plexus. Surprisingly, a large number of radicular and perimedullary veins appeared to be filled with Araldite CY 221 mixture, after injection of this material into the vertebral venous system, implicating reflux via the radicular veins and suggesting insufficiency of the presumed anti-reflux mechanism. Therefore, it was decided to study the radicular veins in order to determine and to investigate the presence or absence of anti-reflux mechanisms within this system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. After polymerization, all cadavers were dissected and the spinal nerve sheaths, including nerve roots, radicular veins and epidural veins, were excised as a whole. After macroscopical examination, serial sections (40 microm) were cut on a freezing microtome and stained in Von Gieson medium. Every third section was stained immunohistochemically with smooth muscle antigen (SMA), to visualize smooth muscle cells. In all cadavers, a number of intradural radicular veins was filled with Araldite. Employing microscopical examination, no bicuspid valves were found. However, four structures were encountered that might serve as ananti-reflux-mechanism: 1) intravenous dural folds, 2) meandrous configuration, and 3) narrowing of the radicular veins at the point of penetration of the dura mater, and 4) varying numbers of smooth muscle fibers in the walls of the intradural and extradural parts of the radicular veins. Reflux via the radicular veins seems to be a physiological phenomenon. Structural valves have not been encountered during this study. Intravenous dural folds, meandrous configuration and narrowing of the transdural part of the radicular veins, and the presence of large numbers of smooth muscle cells in the radicular venous walls suggest the existence of a dynamic reflux-regulating system that has the ability to increase the intravascular resistance under conditions of venous hyperpression, in order to protect the spinal cord from venous pressure waves. Possibly, venous reflux via the radicular veins has a role in selective cooling of the spinal cord.
During the last 120 years, several mechanisms to protect the spinal nerve against traction have b... more During the last 120 years, several mechanisms to protect the spinal nerve against traction have been described. All the described structures were located inside the spinal canal proximal to the intervertebral foramen. Ligaments with a comparable function just outside the intervertebral foramen are mentioned ephemerally. No studies are available about ligamentous attachments of cervical spinal nerves to adjacent vertebrae. To identify and describe ligamentous structures at each cervical level that attaches spinal nerves to structures in the extraforaminal region. An anatomical study of the extraforaminal attachments of the cervical spinal nerves was performed using human spinal columns. Five embalmed human cervical spines (C1-C8) were dissected. The extraforaminal region was dissected bilaterally to describe and measure anatomical structures and their relationships with the cervical spinal nerves. Histology was done on the ligamentous connections of nerves to the adjacent vertebral structures. The cervical spinal nerves are attached to the transverse process of the vertebrae. The connecting ligaments consist mainly of collagenous fibers. At the cervical level, direct ligamentous connections exist between extraforaminal cervical spinal nerves and nearby structures. They may serve as a protective mechanism against traction. In addition, these ligaments play an important role in the positioning of the nerves in the intervertebral foramen.
Several fluorescent tracers were injected intravenously in the tail veins of adult mice, and the ... more Several fluorescent tracers were injected intravenously in the tail veins of adult mice, and the distribution of these substances in the central nervous system and sensory and autonomic ganglia was investigated. Injections of the blue tracers Granular Blue, True Blue and Fast Blue resulted in labeling of the somatomotor and visceromotor nuclei of the brainstem and spinal cord, the paraventricular, supraoptic and arcuate nuclei of the hypothalamus, the area postrema and the sensory and sympathetic ganglia. Following i.v. injections of Nuclear Yellow, labeling occurred only in the median eminence, the area postrema and the sensory and sympathetic ganglia.
Key words." rat retina -nucleus oculomotorius -Nuclear Yellow Phaseolus vulgaris-leucoagglutinin ... more Key words." rat retina -nucleus oculomotorius -Nuclear Yellow Phaseolus vulgaris-leucoagglutinin The centrifugal projection to the eye has been studied in rats with anterograde and retrograde tracing techniques. As a retrograde tracer Nuclear Yellow (NY) was used. Following NY injections into the vitreous body of the eye, labeled neurons were exclusively found bilaterally in nucleus oculomotorius. The course and termination site of the retinopetal fibers were studied with the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). lontophoretic injections of PHA-L in nucleus oculomotorius resulted in labeling of retinopetal fibers which reach the eye via the optic tract and optic nerve. Preterminal arborizations were found in the inner nuclear layer of the retina. In addition, labeled fibers have been observed which seem to terminate within the optic tract and optic nerve. It is suggested that the projection from the nucleus oculomotorius to the retina constitutes a link in the multisynaptic efferent pathway from the visual cortex to the eye, by which the visual cortex can influence the functioning of the retina.
The mammalian vomeronasal organ (VNO) is a well-adjusted chemosensory structure that facilitates ... more The mammalian vomeronasal organ (VNO) is a well-adjusted chemosensory structure that facilitates social and reproductive behavior in mammals. The existence, locality, and function of this organ in human adults remain a matter of discussion. Most authors now agree that a neuroreceptive function of the adult human VNO can be excluded due to the absence of both neural receptive cells associated with the VNO in other mammals despite the enigmatic reports on the effects of pheromones on human behavior. Adult cadavers form European (Caucasoid) descent were used in this article and parasagittal dissection of the heads allowed access to the nasal septa, which were grossly examined for the VNO openings. Tissue samples were collected, embedded in gelatin and serially sectioned through cryomicrotomy. Nissl staining was performed as well as immunohistochemically stained with an antibody against calcium-binding protein. The findings presented here confirm the bilateral presence of the VNO in adult cadavers and demonstrate morphological connections of VNO receptor cells with the underlying capillaries. In addition, possible endocrine activity associated with the epithelium of this chemosensory structure has been demonstrated by the expression of calcium-binding protein in a part of these receptor cells.
Neuropathology and Applied Neurobiology, May 27, 2003
The presence and distribution of misrouted (MR) olfactory projection fibres were studied in the o... more The presence and distribution of misrouted (MR) olfactory projection fibres were studied in the olfactory bulbs of control human brains and in the brains of people who had suffered from Parkinson's and Alzheimer's disease. It appeared that MR fibres, that is, fibres that terminate deep into the glomerular layer, are a common phenomenon in the bulbs of aged people. In all but one of the bulbs studied, MR fibres are present. The amount of MR fibres is not related to age. With a few exceptions, the MR fibres are restricted to the external plexiform layer (EPL). Only in Parkinson bulbs the MR fibres occasionally form glomerulus‐like structures. These pseudo glomeruli are located in the EPL. It is concluded that MR olfactory projection fibres are a normal phenomenon in the human olfactory bulb. In nonhuman mammalians, MR fibres have only been observed in foetal and neonatal olfactory bulbs. Possibly, the age‐related loss of mitral cells, which are the natural synaptic targets for the olfactory projection fibres, may play a role in the aberrant behaviour of the MR olfactory receptor cell axons. The ectopic glomerulus‐like structures in Parkinson bulbs share some characteristics with normal rat glomeruli that are not observed in normal human olfactory glomeruli. This may refer to possible changes in the genetic content of olfactory structures in Parkinson patients.
The aim of the present study is to provide a complete description of the distribution of choline ... more The aim of the present study is to provide a complete description of the distribution of choline acetyltransferase (ChAT) immunoreactivity (i) in the brain of the lizard Gallotiagalloti, on the basis of two different primary antisera: rat anti-ChAT and rabbit anti-chicken C U T. Considering that the brain is a segmented structure, we have analysed our data with respect to transverse segmental domains (or neuromeres), which have been previously described by several authors in the brain of vertebrates. In the telencephalon, ChATi neurons are seen in the cortex, anterior dorsal ventricular ridge, basal ganglia, diagonal band, and bed nucleus of the stria terminalis. Further caudally, ChATi cell bodies are located in the preoptic area, hypothalamus, habenula, isthmus, and all motor efferent centers of the brainstem and spinal cord. Plexuses of ChATi fibers are observed in the areas containing cholinergic cell bodies. In addition, distinct plexuses are found in the cortex, the posterior dorsal ventricular ridge, the neuropiles of all primary visual centers of the diencephalon and mesencephalon, and several non-visual nuclei of the brainstem. The distribution of ChAT immunoreactivity in the brain of G. galloti resembles in many respects that of other vertebrates, and differences are mainly observed in the pretectum and midbrain tectum. Transverse segmental domains were identified in the brainstem and forebrain of Gallotia when the cranial nerve roots and fiber tracts were used as a reference, and most cranial motor nuclei were found to occupy the same segmental positions as have been reported in the chick.
In the present study HRP injections have been placed in various thalamic areas in order to invest... more In the present study HRP injections have been placed in various thalamic areas in order to investigate spinothalamic projections in the lizard Varanus exanthematicus. It appeared that the spinal cord projects to three different thalamic areas: nucleus dorsomedialis, nucleus ventrolateralis, and an area that includes both the nucleus dorsolateralis and nucleus intermediodorsalis. Spinal neurons projecting to nucleus dorsomedialis are localized bilaterally at the medial side of the dorsal horn. Following injections in nucleus ventrolateralis, labeled neurons were found bilaterally in area VII and VIII, whereas nucleus dorsolateralis and nucleus intermediodorsalis receive a bilateral input mainly from areas V and VI.
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