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Biomedical subjects

E Marani

Publications and source records attributed to E Marani.

At least 55 records · Page 3Linked to original sources
PubMed1996

Immunocytochemical localization of neurofilaments in the fibre systems of the developing rat spinal cord white matter.

The appearance and localization of the protein subunits of neurofilaments in the ascending and descending fibre systems of the developing rat spinal cord white matter were studied. The monoclonal antibody NF-90 (specific for the phosphorylated NF-L, NF-M and NF-H subunits) was used as neurofilament marker in fresh cryostat and Bouin fixed paraffin sections. The results were compared with Nissl and Bodian stained sections. Within the white matter, phosphorylated neurofilament proteins were expressed with regional variations. At embryonal day 12 (E12), the first positive fibres were found in the lateral funiculus. During further development, the peripheral region of the lateral funiculus showed an intense neurofilament staining, due to the presence of a higher number of fibres. From postnatal day 12 (P12) on, an increased amount of neurofilaments was found in the region close to the periphery, probably due to the presence of large calibre fibres. The dorsolateral part of the lateral funiculus filled in with fibres after birth, which indicated the extended development of the rubrospinal tract. At E13, positive fibres were present in the ventral commissure and the ventral funiculus. At E14, an increased amount of neurofilaments was detected in the periphery of the ventral funiculus. At maturity, an intense staining in the subsurface region could be found, due to the presence of large calibre fibres of the fasciculus longitudinalis medialis. At E13, the first neurofilament positive fibres were present in the dorsal funiculus. At this day, a concentration of fibres was found in the dorsal part of the dorsal root bifurcation zone and three days later, more fibres were detected in the medial part of the dorsal funiculus. At E18, a higher number of fibres was present in the dorsal region of the fasciculus gracilis. The mature fasciculus cuneatus showed an intense neurofilament staining, which was mainly present in large calibre fibres. The ventral part of the dorsal funiculus filled in with neurofilament positive fibres after birth. This indicated the relative late arrival of the corticospinal tract.

Animals↗
PubMed1996

Reinnervation of avulsed and reimplanted ventral rootlets in the cervical spinal cord of the cat.

Spinal nerve root avulsions frequently occur in brachial plexus injuries caused by traction. Such lesions are considered to afflict the central nervous system (CNS) and are, therefore, believed to be beyond surgical repair. The present experimental study was initiated to challenge this hypothesis. The ventral rootlets of C-7 were avulsed from the spinal cord in 28 cats via an anterior approach and subsequently reimplanted into the cord at the site of origin. In nonoperated control cats and cats undergoing reimplantation, electrophysiological experiments were performed and horseradish peroxidase was administered to the spinal nerve on the reimplanted side after survival times ranging from 6 to 293 days. Spinal cord sections in all cats were stained for neurofilament, acetylcholinesterase (AChE), Nissl, and glial fibrillary acidic protein. Horseradish peroxidase-labeled ventral horn motoneurons were found as early as 14 days after reimplantation and their number increased with time. On Days 209 and 293, the number of labeled neurons equaled the number of labeled ventral horn neurons in the two control cats that did not undergo surgery. Starting on Day 6 after reimplantation, the appearance of the ventral horn and the white matter in the neurofilament, AChE, and Nissl-stained sections changed as a result of the CNS response to the injury. A return to their normal appearance could be observed in these stainings from Day 209 onward. Glial fibrillary acidic protein-positive astrocytic tissue was consistently found in the ventral horn and in the white matter reimplantation area. From Day 69 onward, electrophysiological stimulation of the spinal nerve C-7 on the reimplanted side elicited an electromyogram response in the spinodeltoid muscle. The latency and threshold intensity of the C-7 responses were initially increased but equalized to match the nonoperated controls between 98 and 122 days after reimplantation. The results of this study show that functional regeneration of ventral horn neurons after root avulsion and subsequent reimplantation in the cat is possible.

Acetylcholinesterase↗
PubMed1995

Neuronal circuitry of the lower urinary tract; central and peripheral neuronal control of the micturition cycle.

A new presentation technique is introduce to describe the neuronal circuitry involved in the control of the uropoëtic system and its control mechanisms during the micturition cycle. This method is based on the preparation of flow charts and is applied to the discussion of four qualitative models which are derived from the literature. Opinions concerning the reflex arcs and supraspinal connections said to be involved in micturition and continence are different and sometimes contradictory. Little is known about supraspinal (inter)connections and their function in micturition control is still fragmentary. The control mechanisms which terminate voiding are not totally clear. Moreover, the role of the pelvic floor musculature in the control of the lower urinary tract is probably underestimated. The flow charts presented in this paper contribute to the future design of a single complete qualitative model representing the general central and peripheral nervous connections and control mechanisms. Such a model would provide an approach for future research in neuromodulation and neurostimulation of the uropoëtic system and a reduced version could be used for quantitative modelling, e.g. in neural network simulations.

Humans↗
PubMed1995

CD15 and HKN-1 reveal cerebellar compartments with a complex overlap.

The CD15-epitope in the cerebellar cortex is expressed by Bergmann glial fibers which are organized in symmetrical iterative stripes. Their arrangement appears complementary to the pattern described for the organization of compartments demonstrated by any other marker used so far. HNK-1 however, reveals stripes that are not complementary to the general pattern for the organization of compartments.

Animals↗
PubMed1995

Simultaneous demonstration of CD15 and alkaline phosphatase activity in cryostat sections of rat fetuses: a detailed technical description for the developing brain.

CD15 and alkaline phosphatase are significant markers of the developing central nervous system. CD15 is known for its interaction in cell-cell contacts, while the presence of alkaline phosphatase is related to the formation of neuronal connections. This paper describes a combined immunocytochemical and enzyme histochemical technique to demonstrate both embryonic markers in the same cryostat section. The monoclonal antibody 3B9, which was used for the detection of CD15 recognizes the immunodominant carbohydrate structure alpha-1,3-Fucosyl-N-Acetyl-Lactosamine also known as X, LewisX, FAL or SSEA-1. This antigen dissolves and is easily rinsed out of the section. The procedure starts off with the detection of CD15. The results of the immunocytochemical procedure is a reaction product which is stable at a high pH, preventing loss of the immunocytochemical reaction product during the subsequent alkaline phosphatase detection. The other embryonic marker, alkaline phosphatase, can only be demonstrated enzymehistochemically if the enzyme is still active. The immunocytochemical localization procedure decided for, does not inactivate alkaline phosphatase totally. From the colorimetrical and histochemical alkaline phosphatase determinations it was concluded that the residual alkaline phosphatase activity detected with this technique, could be intensified by adding Mg(2+)-ions to both the colorimetrical and histochemical incubation media.

Alkaline Phosphatase↗
PubMed1995

Combining microwave stabilization and microwave-stimulated fixation of brain tissue with microwave-stimulated staining.

Microwave stabilization of rat brain tissue using saline was compared with microwave-stimulated fixation using either formaldehyde or Kryofix. Sections were stained according to the microwave-adapted Nissl, Klüver-Barrera, and Bodian methods. Depending on the preparative choice the microwave staining method had to be adjusted. Optimal combinations of preparative techniques and staining methods are feasible. In most cases the microwave saline-stabilized and microwave Kryofix-treated sections were better suited for application in neurohistology than the microwave formaldehyde-treated sections for light microscopy.

Animals↗
PubMed1995

Immunocytochemical localisation of microtubule-associated proteins 1b and 2 in the developing rat spinal cord.

The straightforward anatomical organisation of the developing and mature rat spinal cord was used to determine and interpret the time of appearance and expression patterns of microtubule-associated proteins (MAP) 1b and 2. Immunoblots revealed the presence of MAP1b and 2 in the early embryonic rat spinal cord and confirmed the specificity of the used anti-MAP mouse monoclonal antibodies. The immunocytochemical data demonstrated a rostral-to-caudal and ventral-to-dorsal gradient in the expression of MAP1b/2 within the developing spinal cord. In the matrix layer, MAP1b was found in a distinct radial pattern distributed between the membrana limitans interna and externa between embryonal day (E)12 and E15. Immunostaining for vimentin revealed that this MAP1b pattern was morphologically and topographically different from the radial glial pattern which was present in the matrix layer between E13 and E19. The ventral-to-dorsal developmental gradient of the MAP1b staining in the spinal cord matrix layer indicates a close involvement of MAP1b either in the organisation of the microtubules in the cytoplasmatic extensions of the proliferating neuroblasts or neuroblast mitosis. MAP2 could not be detected in the developing matrix layer. In the mantle and marginal layer, MAP1b was abundantly present between E12 and postnatal day (P)0. After birth, the staining intensity for MAP1b gradually decreased in both layers towards a faint appearance at maturity. The distribution patterns suggest an involvement of MAP1b in the maturation of the motor neurons, the contralaterally and ipsilaterally projecting axons and the ascending and descending long axons of the rat spinal cord. MAP2 was present in the spinal cord grey matter between E12 and maturity, which reflects a role for MAP2 in the development as well as in the maintenance of microtubules. The present description of the expression patterns of MAP1b and 2 in the developing spinal cord suggests important roles of the two proteins in various morphogenetic events. The findings may serve as the basis for future studies on the function of MAP1b and 2 in the development of the central nervous system.

Animals↗
PubMed1994

The rostrocaudal organization in the dorsal root ganglia of the rat: a consequence of plexus formation?

The dorsal root ganglia (DRGs) of the rat have a rostrocaudal organization. This organization can most easily be demonstrated in fetal and neonatal rats because the spatial relationships of their DRGs are maintained better in tissue sections than those of mature rats. This review is concerned with the way in which the rostrocaudal organization of the DRGs is generated. Wheat germ agglutinin--horseradish peroxidase/horseradish peroxidase labeling of peripheral nerves of the brachial and lumbar plexuses shows that the position of the somata of the sensory neurons of the labeled nerves can be restricted to rostral or caudal halves of DRGs. Labeling of the thoracic nerve or its branches always results in labeling throughout the entire thoracic DRG. After application of the marker to forelimb nerves, it was observed that whenever a DRG is labeled only partially, its spinal nerve is correspondingly labeled partially as well. These data suggest that the rostrocaudal organization in the DRG is related to the formation of the plexuses. During development nerve fibers can be segmentally labeled, using the subdivision of the DRGs into a rostral and a caudal half to keep together as they find their way through the plexus. Application of label to forelimb skin, hindlimb skin and even thoracic skin can result in labeling of rostral or caudal halves of a DRG. A possible explanation might be that each dermatome can be divided into a skin area innervated by the rostral half of a DRG and a skin area innervated by the caudal half of the same dorsal root ganglion. In the rat, the segmental sensory innervation of muscles during development has not yet been investigated. The question of whether the segmental unit of innervation of a muscle is a whole DRG or half a DRG therefore still remains unanswered.

Animals↗
PubMed1994

Overview of Microwave Applications in the Neurosciences.

This paper gives an overview of Microwave Applications in the Neurosciences and introduces this issue of the Journal of Neuroscience Methods. Emphasis is laid on: temperature, hotspots, hazards and cycle times in the use of the microwave oven. Consequences of the tissue dimensions and masking of antigens are discussed. Special problems encountered are: bulk preparation of specimens, brain electron microscopy, cooling of specimens during microwaving and the combination of microwave techniques. The recent developments discussed are vacuum-microwave application for large brain specimens and antigen retrieval.

Animals↗
PubMed1993

Interconnections of the upper ventral rami of the human sacral plexus: a reappraisal for dorsal rhizotomy in neurostimulation operations.

The extension of a dorsal rhizotomy in bladder stimulation patients is partly determined by connections between the ventral rami of the second, third, and fourth sacral spinal nerves. The literature is inconclusive on interconnections of these ventral rami in the human sacral plexus. The sacral plexuses of ten human cadavers were dissected in this gross anatomy study. In nine cases a branch connecting the ventral rami of the second and third sacral spinal nerves was found. Electron microscopy demonstrated the presence of thick myelinated fibers in this branch. In the male plexuses this branch formed the only link between the second sacral spinal segment and the pelvic plexus. The ventral ramus of the second sacral nerve always contributed to the pudendal nerve, whereas involvement of the ventral rami of the first and third sacral nerves differed individually and intersexually.

Female↗
PubMed1993

A rostrocaudal somatotopic organization in the brachial dorsal root ganglia of neonatal rats.

A rostrocaudal somatotopic organization in the rat lumbar dorsal root ganglia (DRGs) during development has been demonstrated. The present study shows that such a rostrocaudal somatotopic organization also exists in the brachial DRGs of neonatal rats. WGA-HRP or WGA-HRP/HRP injections into the forepaw of neonatal rats gave rise to completely and partially labeled DRGs. Partial labeling always concerned the caudal or rostral halves of the rostral-most or caudal-most labeled DRGs, respectively. Labeling of forelimb nerves (cutaneous branch of the musculocutaneous nerve, median and ulnar nerve) in neonatal rats also resulted in whole labeled DRGs and labeled rostral or caudal halves of DRGs. Accordingly, just as was found for the hind limb nerves, the position of the somata of the sensory neurons of forelimb nerves can be restricted to the rostral or caudal half of a DRG. Moreover, it was observed that the rostrocaudal organization in the brachial DRGs is maintained in the spinal nerves. Application of tracer to the cut end of intercostal nerves in neonatal rats produced labeling of one whole thoracic DRG. It is therefore possible that the rostrocaudal organization in the brachial and lumbar DRGs is a consequence of the formation of the plexuses. In one instance a subdivision in the labeling pattern of a midthoracic DRG was noticed after a WGA-HRP injection into the thoracic wall of a neonatal rat. The whole thoracic DRG was labeled except the dorsorostral corner. This indicates that during development, some kind of somatotopic organization may exist also in the thoracic DRG.

Animals↗
PubMed1993

The dorsoscapular nerve in traumatic brachial plexus lesions.

The origin and course of the nerval innervation of the levator scapulae and rhomboid muscles was studied in four human cadavers. Special attention was given to surgical anatomy. The levator scapulae muscle receives two small segmental nerves from C3 and C4, respectively. The rhomboid muscle receives two segmental nerves, one from C4 and the other from C5. Moreover, in a series of 137 patients with a traumatic brachial plexus lesion, the linkage between levator scapulae and rhomboid muscle function impairment and site of the brachial plexus lesion was studied. Paresis of one or both of these muscles was noted in 13 cases. It was concluded that the rhomboid muscle may function on a single C4 nerve supply without any loss of strength. Arguments are put forward to support the relevance of rhomboid muscle testing in the assessment of brachial plexus lesions.

Adult↗
PubMed1993

The tensile testing machine applied in the study of human nerve rupture: a preliminary study.

A tensile testing machine was used to provoke lesions of fixed and unfixed brachial plexus nerves. The forces and mechanical work were measured before and during rupture. Fixed nerves resist continued tensile forces better than unfixed nerves do. Increasing the speed of the tensile forces results in a decrease of the extension a brachial plexus nerve can withstand. The mechanical work needed to start rupture is equal to the mechanical work used to complete rupture of the nerve.

Biomechanical Phenomena↗
PubMed1993

Ultrastructural study on avulsion effects of the cat cervical moto-axonal pathways in the spinal cord.

After selective avulsion of the ventral root cervical 7 (C7) from the adult cat spinal cord, the intraspinal trajectories of the torn axons in the white matter were studied at different survival times. Two phases could be discerned: an early phase which showed changes that occurred up to 14 days after avulsion and a second phase from day 30 onwards. Two days postoperatively, considerably swollen, empty myelin sheaths occurred, which remained present up to 14 days after avulsion. A primary increase in the number of glial cells (microglia) was noted on days 2 and 4 after avulsion. Ultrastructurally, unmyelinated and myelinated terminal clubs were found 8 and 14 days after avulsion. These clubs were characterized as cones of growth, related to axonal regeneration. A second glial increase was present after 30 days. At that time, the entire moto-axonal pathway clearly showed a degeneration pattern. This finding was light microscopically confirmed by an increase of GFAP-positive astrocytes. During the first 30 days, a front of small calibre myelinated axons, starting at the transition zone of the grey and white matter traversed halfway through the moto-axonal pathway. However, on days 60 and 90 no further shift of the front had occurred.

Animals↗