Allorecognition of artificial nerve guides filed with human Schwann cells: an in vitro piloot study.
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Animals↗
Biomedical subjects
E Marani
Publications and source records attributed to E Marani.
Spatiotemporal distribution of dying neurons during early mouse development.
Apoptosis is a critical cellular event during several stages of neuronal development. Recently, we have shown that biotinylated annexin V detects apoptosis in vivo in various cell lineages of a wide range of species by binding to phosphatidylserines that are exposed at the outer leaflet of the plasma membrane. In the present study, we tested the specificity by which annexin V binds apoptotic neurons, and subsequently investigated developmental cell death in the central and peripheral nervous system of early mouse embryos at both the cellular and histological level, and compared the phagocytic clearance of apoptotic neurons with that of apoptotic mesodermal cells. Our data indicate: (i) that biotinylated annexin V can be used as a sensitive marker that detects apoptotic neurons, including their extensions at an early stage during development; (ii) that apoptosis plays an important part during early morphogenesis of the central nervous system, and during early quantitative matching of brain-derived neurotrophic factor and neurotrophic factor 3 responsive postmitotic large clear neurons in the peripheral ganglia with their projection areas; and (iii) that apoptotic neurons are removed by a process that differs from classical phagocytosis of non-neuronal tissues.
Animals↗
The neuronal control of the lower urinary tract: A model of architecture and control mechanisms.
The human micturition cycle is controlled by central and peripheral nervous structures and connections. In literature, no complete or generally accepted model describes the principles of micturition control. In this paper, the integration of (neuro-)anatomy, (neuro-)physiology and control theory is used to describe and model the neuronal control of the lower urinary tract. Neuroanatomy supplies the most basic information necessary for the modellation of the peripheral pathways and central connections involved in the control of the uropoetic system. It is found that not all the nervous structures and connections have been identified as such yet. The linking up between several nervous structures (e.g., the presence of central and peripheral relay stations) is not completely clear. A s a consequence, each model to describe the micturition cycle from the perspective of control theory is yet of limited physiological value as it cannot exceed a rather general level of modellation. Adding functional considerations (neurophysiology and control theory) to the neuroanatomical skeleton completes the model. Some control mechanisms active during the micturition cycle can still not be revealed in detail. Crucial questions on the neuronal innervation of the human uropoetic system and the control mechanisms active during the micturition cycle remain, like how the supraspinal trigger mechanisms for micturition are organised, or how the voluntary cessation of voiding is realised. A simplified version of the model discussed in this paper can already be used for mathematical modelling, e.g., neural network simulations.
Afferent Pathways↗
Three dimensional registration of mechanical bladder activity using polystyrene fluorescent spheres: A technical note.
Optical marker tracing methods have been applied successfully in recent years to quantify local material deformation of heart tissue, skin and striated muscles. In this study, polystyrene fluorescent spheres (d = 0.6 mm) are glued to the ventral serosal bladder wall in the rabbit. Three dimensional video registration of the polystyrene spheres is used to calculate two directions of principal strain (epsilon (1), epsilon (2) ) on the bladder surface in vivo. The aim is to investigate the feasibility of the technique for this new application in two experimental circumstances: during spontaneous bladder wall activity and after electrical stimulation of bladder innervating nerve fibers. During spontaneous activity, random contraction and relaxation occurred simultaneously and separately across the bladder wall for the two principal strains epsilon (1) and epsilon (2). After extradural electrical stimulation of sacral nerve root S2, the principal strains epsilon ( 1) and epsilon (2) synchronized in time in such a way that epsilon ( 1) and epsilon (2) both represented contraction or both represented relaxation. One and the same bladder wall area passed through phases of contraction followed by relaxation and vice versa. After multiple stimulation periods, the coordination between the two principal strains during stimulation was reduced. This technique allows to identify local areas of contraction and relaxation in the intact bladder wall in vivo. Three dimensional video registration of polystyrene fluorescent spheres to study bladder wall contraction and its relaxation proved to be a feasible technique, with which electrical stimulation effects and spontaneous activity could be measured.
Animals↗
Microtubule-associated protein 1a is involved in the early development of the rat spinal cord.
The expression of microtubule-associated protein 1a (MAP1a) in the developing rat spinal cord was studied using the monoclonal antibody BW6. Immunoblots of microtubule preparations revealed the presence of MAP1a in spinal cord tissue of rats aged embryonal day 16 and postnatal day 0. The spinal cord matrix layer, between embryonal days 12-17, displayed a pattern of MAP1a-positive processes, horizontally oriented in between the membrane limitans interna and externa. The mantle layer stained intensely for MAP1a between embryonal day 12 and postnatal day 2. MAP1a was found in neuronal cell bodies, axons and dendrites, located mainly in the ventral and intermediate mantle layer. In the marginal layer, MAP1a-positive axons could be observed between embryonal days 14-18. During further development, the intensity of the MAP1a staining in the spinal columns gradually decreased. These expression patterns indicate an involvement of MAP1a in the proliferation and differentiation of neuroblasts, and the maturation of the long spinal fiber systems, i.e. early events in spinal cord development
Aging↗
Microwave applications in neuromorphology and neurochemistry: safety precautions and techniques.
In science, the introduction of a new method is never easy, not even if it concerns the use of a simple microwave oven. Most scientists do not realize the numerous applications of microwave techniques. This paper gives a broad overview of the application of microwave techniques in neuromorphology and neurochemistry, starting with a historical overview ranging from the introduction of microwave techniques as a scientific method in the 1970s to present. Organizations and publication rules are highlighted in the next part. The effect of microwave irradiation is discussed in two sections relating to microwave effects on the whole organism and on the neuron. The main body of the paper discusses the application of microwave techniques in the fields of neuromorphology and neuropathology. The paper then presents aspects of microwave irradiation as applied to ELISA techniques. In addition, cell fusion and cell reproduction under microwave irradiation are discussed.
Animals↗
Cell replication rates and processes concerning antibody production in vitro are not influenced by 2.45-GHz microwaves at physiologically normal temperatures.
Several contradictory papers concerning the effects of microwaves on living organisms and on in vitro cell suspensions have been published through the years. These papers are difficult to interpret, because temperature measurement data are often lacking. Reliable temperature measurements are important, because they enable one to determine whether the observed microwave effects are thermal or nonthermal. Therefore, a method was developed to investigate microwave effects on cellular processes, in which the temperature was precisely monitored during microwave treatment using a fiberoptic thermometer. This method involved the processes required for in vitro production of monoclonal antibodies. Monoclonal antibodies are vital ingredients in (microwave-stimulated) immunostaining techniques and ELISAs, which have become important techniques in neuroscience. The effects of 2.45-GHz microwaves on mouse myeloma and (neural) hybridoma cell replication rates and on antibody production were investigated. In addition, the effects on the cell fusion abilities of spleen lymphocytes and myeloma cells and on in vitro immunization were studied. The results of this study show no effects of microwaves on either of the processes mentioned using exposure times up to 5 h a day at a physiologically normal temperature of 37 degrees C. It was concluded that the effects of 2.45-GHz microwaves detected at higher temperatures are thermal effects and that no indications for nonthermal 2.45-GHz microwave effects exist under the exposure conditions used in the present study.
Animals↗
The process of decompaction and myelin removal after C7 ventral root avulsion in the cat.
An electron microscopical study was carried out on the ventral horn in order to investigate the microvascular changes after C7 ventral root avulsion in cats. Endothelial cells: At 2 days after avulsion the endothelial cells contained vacuoles filled with fibrous-like substances. After 14 days the endothelial phagosomes also contained myelin sheath-like and "soap-bubble" structures. Tight junctions between the endothelial cells remained present without exception. From 14 up to 90 days, intraluminal debris was observed. Edema and glia: From 2 up to 30 days after avulsion perivascular edema was noted around blood vessels and polymorphonuclear granulocytes were found mainly in the peri-endothelial space. Eight days after avulsion, the number of astrocytic processes around the blood vessels and the phagocytic activity of perivascular cells increased. Myelin sheath-like structures were encountered in phagosomes of the pericytes. After 14 days the distribution of astrocytic processes around the blood vessels had stabilized and remained so until day 90 after avulsion. In the same period the phagocytic activity decreased, and the myelin sheath-like material in the perivascular cell phagosomes gradually disappeared. The amount of microglial cells around the blood vessels showed an increase after 30 days survival and then stabilized. These results indicate transport of debris from the neuropil across the endothelial cells into the blood vessel lumen after ventral root avulsion.
Animals↗
Trophic and tropic factors in the development of the central nervous system.
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Animals↗
Immunocytochemical localization of the AMPA receptor subunits in the mesencephalic trigeminal nucleus of the rat.
The mesencephalic trigeminal nucleus is composed of large (35-50 microns) pseudo-unipolar neurons. Closely associated with them are small (< 20 microns) multipolar neurons. An unique peculiarity of the pseudo-unipolar perikarya is that they receive synaptic input from various sources, which sets them apart from the dorsal root and cranial nerves sensory ganglia neurons. Whereas glutamate is the best neurotransmitter candidate in pseudo-unipolar neurons, glutamatergic input into them has not yet been reported. AMPA glutamate receptors are implicated in fast excitatory glutamatergic synaptic transmission. They have been localized ultrastructurally at postsynaptic sites. This study demonstrates that the pseudo-unipolar neurons of the mesencephalic trigeminal nucleus express AMPA glutamate receptor subunits, which indicates that these neurons receive glutamatergic input. Serial sections from the rostral pons and midbrain of Sprague-Dawley rats were immunostained with antibodies against C-terminus of AMPA receptor subunits: GluR1, GluR2/3, and GluR4. The immunoreaction was visualized with avidin-biotin-peroxidase/DAB for light and electron microscopy. With GluR1 antibody only the smallest multipolar neurons were recognized as immunopositive within the mesencephalic trigeminal nucleus. GluR2/3 stained the pseudo-unipolar neurons intensely within the entire rostro-caudal extent of the nucleus. In addition the former antibody stained small multipolar neurons within the mesencephalic trigeminal nucleus, though with somewhat larger dimensions than those immunoreactive for GluR1. Whereas the overall staining with GluR4 antibody was scant, those pseudo-unipolar neurons that were stained, were strongly stained. Furthermore, a considerable number of microglial cells within and surrounding the mesencephalic trigeminal nucleus displayed very intense immunoreactivity for GluR4. These results are discussed in the light of the glutamate receptor subunit composition.
Animals↗
Evidence for a possible glycinergic inhibitory neurotransmission in the midbrain and rostral pons of the rat studied by gephyrin.
The data on the glycinergic transmission in the rostral brainstem are both few and controversial. The present report provides evidence for a possible glycinergic transmission in Sprague-Dawley rats, based on observations of immunocytochemical labeling for gephyrin, a 93 kDa protein and a component of the functional glycine receptor. A monoclonal antibody against gephyrin was used, and the reaction product was visualized by means of avidin-biotin-peroxidase procedure. The reaction product in midbrain and rostral pons was found in neuronal perikarya and in proximal dendrites but in some cases the most distal dendritic branches were also labeled. The neuropil usually displayed a moderate staining with finely granulated reaction product. The most significant immunocytochemical signal was mainly encountered in large and medium-sized neuronal populations of the motor cranial nerve nuclei (III, IV, V), in the reticular formation (laterodorsal tegmental nucleus, pedunculopontine tegmental nucleus, deep mesencephalic nucleus), in the red nucleus, in the intermediate and deep gray strata of the superior colliculus. Only in the substantia nigra and the inferior colliculus the parvocellular cell populations were mainly labeled. The present data suggest a significant inhibitory glycinergic neurotransmission in the rostral brainstem, probably mediated by interneurons.
Animals↗
Glass ring-wall sealing to prevent leakage from electrode culture chambers: a technical note.
Entellan is a good sealing substance for culture chamber walls and does not interfere with the growth of the cultured DRG cells. If the Entellan becomes brittle the glass ring can easily be loosened by placing the chamber with the sealed ring for 24 hrs in xylene. Repeated rinsing with xylene and subsequently with hydrated steps of ethanol (100%-70%-30%) allows the ring-wall and chamber floor with its electrodes to be reused.
Animals↗
The trigeminal motonucleus in man.
The constitutional elements of the mototrigeminal nucleus in man are described. Apart from the well-known alpha motoneurons, interneurons and gamma motoneurons can be discerned. Cortical projections to the mototrigeminal nucleus in man arise both ipsilateral and contralateral. The contralateral projection is dominant. Terminal cortical input is present on the alpha-motoneurons in man.
Afferent Pathways↗
Innervation of "painful" lumbar discs.
STUDY DESIGN: The authors investigated the innervation of discographically confirmed degenerated and "painful" human intervertebral discs. OBJECTIVE: To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs. SUMMARY OF BACKGROUND DATA: The innervation of intervertebral discs has previously been extensively described in fetal and adult animals as well as humans. However, little is yet known about the innervation of severely degenerated human lumbar discs. The question may be posed whether a disc that has been removed for low back pain possesses an increased innervation compared with normal discs. METHODS: The presence of nerve fibers was investigated using acetylcholinesterase enzyme histochemistry, as well as neurofilament and substance P immunocytochemistry. From 10 degenerated and 2 control discs, the anterior segments were excised and their nerve distribution studied by examining sequential sections. RESULTS: In all specimens, nerve fibers of different diameters were found in the anterior longitudinal ligament and in the outer region of the disc. In 8 of 10 degenerated discs, fibers were also found in the inner parts of the disc. Substance P-immunoreactive nerve fibers were sporadically observed in the anterior longitudinal ligament and the outer zone of the anulus fibrosus. CONCLUSIONS: Findings indicate a more extensive disc innervation in the severely degenerated human lumbar disc compared with normal discs. The nociceptive properties of at least some of these nerves are highly suggested by their substance P immunoreactivity, which provides further evidence for the existence of a morphologic substrate of discogenic pain.
Acetylcholinesterase↗
Nerve grafting from spinal cord to spinal nerve: a microsurgical technique in cats.
A ventral surgical approach is described for the grafting of autologous saphenous nerves between the spinal cord and the avulsed C7 ventral root in the cat. To overcome serious blood loss from the epidural venous plexus, the cats were hyperventilated (end tidal PCO2 to about 23 mmHg) and controlled hypotension was induced (mean arterial pressure to about 60 mmHg). After selective avulsion of the ventral rootlets C7 the saphenous grafts were implanted into the spinal cord and coaptated to the avulsed spinal nerve. The combination of advanced anesthetic methods and microsurgical techniques appeared to be mandatory to achieve a low surgical mortality. Regenerated axons were retrogradely traced using retrograde horseradish peroxidase (HRP), and their functional recovery was evaluated by means of electrophysiological methods.
Anesthesia↗
The search for vacuo-microwave technique: the vacuum-microwave oven.
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