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E Marani

Publications and source records attributed to E Marani.

At least 19 recordsLinked to original sources
PubMed1992

Spontaneous and stimulated firing in cultured rat suprachiasmatic neurons.

Neurons from the suprachiasmatic nucleus (SCN) of the hypothalamus, the site of a circadian pacemaker in mammals, were isolated from embryonic rat. After mechanical dissociation neurons were brought into culture for 1-2 weeks, using a chemically defined medium. Recordings were made from 74 bipolar neurons using two different configurations of the patch-clamp technique. During cell attached patch recordings, 45% of neurons fired spontaneously. The mean firing rate was 0.7 +/- 0.6 Hz and the firing pattern was irregular. In whole cell recordings 73% of the investigated neurons showed spontaneous activity with an irregular firing pattern. The mean spontaneous firing rate with an intracellular Cl- concentration of 145 mM was 1.0 +/- 0.6 Hz. The resting membrane potential of the bipolar neurons was estimated to be -62 +/- 24 mV. An intracellular Cl- concentration of 145 mM depolarised the membrane potential. It also increased the probability of spontaneous firing. A depolarising current stimulus produced an action potential with a threshold voltage of -46 +/- 9 mV. Suprathreshold stimuli resulted in repetitive firing with a mean frequency of 12 +/- 4 Hz. The minimum interspike interval was 52 +/- 14 ms. All action potentials either occurring spontaneously or elicited by current stimuli were abolished by the Na(+)-channel blocker TTX. These results indicate that our cultured neurons have some electrophysiological properties in common with SCN neurons in brain slices and in vivo.

Action Potentials↗
PubMed1992

The expression of CD15 in dissociated cultured rat dorsal root ganglion cells.

This study describes the presence of CD15 in dorsal root ganglia neurons in five experimental conditions: chemically defined medium and the same medium with added nerve growth factor, retinoic acid or antibodies against insulin or tyrosine phosphate. Positive astrocyte controls were used to differentiate the monoclonal antibodies that did not react with CD15. Those monoclonal antibodies which detected CD15 in this positive control were also used to study CD15 positivity in dorsal root ganglion cells. This study shows: (i) masking of the CD15 antibody, which influences the detection capacity of the monoclonal antibodies used; (ii) that CD15 discerns two subpopulations of DRG neurons: a CD15-positive and a CD15-negative population; (iii) that CD15 expression is not involved in the outgrowth of protrusions or the wrapping by non-neuronal cells of DRG neurons.

Animals↗
PubMed1992

Expression of the carbohydrate epitope 3-fucosyl-N-acetyl-lactosamine (CD15) in the vertebrate cerebellar cortex.

The distribution of the carbohydrate epitope CD15 was investigated on paraffin sections of the brains of man and mammals (monkey, dog, rabbit, rat, mouse, dolphin), reptile, bird and fish by means of immunohistochemistry. This paper demonstrates a differential expression of the CD15 epitope in the cerebella of these various vertebrates. CD15 positivity was found on glial cells and neuronal structures. In adult brains two major distribution patterns were distinguished: one with very intense labelling of the molecular layer, for which the rat is representative, the other with very low immunoreactivity in this layer (mouse). Amongst the rodents (mouse, rat and rabbit), as well as the monkey and human, the positivity in the molecular layer could be attributed to Bergmann fibres of the Golgi epithelial cells. A typical parasagittal band pattern, present in the mouse molecular layer for CD15, which is absent in rat and rabbit molecular layer, is present during human cerebellar development. CD15 positivity on neuronal structures is found on parallel fibres in the developing human, on the lower stellate cells in the dog, and in climbing fibres of the dolphin and, presumably, the catfish too. Moreover, within the parrot cerebellum, large CD15-positive mossy fibre-like endings are found just at the infraplexiform layer.

Adolescent↗
PubMed1992

Transient expression of stage-specific embryonic antigen-1 (CD15) in the developing dorsal rat spinal cord.

The localization of CD15 (synonyms: stage-specific embryonic antigen-1 (SSEA-1), 3(alpha)-fucosyl-N-acetyl-lactosamine or FAL), which is implicated in neuronal differentiation, in the developing dorsal rat spinal cord was studied by immunocytochemistry. A embryonal day 9 (E9), SSEA-1 was detected in the neural ectoderm and, at E11, in cells near the ventricle of the matrix layer. This localization indicated that SSEA-1 is present in proliferating premigratory cells of the rat spinal cord. Between E12 and E16, cells of the alar plate expressed SSEA-1. Expression of the antigen was restricted to neuroblasts that will form the dorsal horn. SSEA-1, therefore, can be used at this stage as a marker for a subdivision of the matrix layer. At E14, the dorsal root entrance zone showed SSEA-1. This indicated that SSEA-1 is associated with ingrowing primary afferents. From E16 on, SSEA-1 was present in the dorsal raphe, which suggested a function for SSEA-1 in the guidance of developing fibres. After E17, the antigen was also found within the dorsal mantle layer. SSEA-1 was first present in Rexed's laminae II, IV and V. Later on in development the antigen was detected only in Rexed's laminae II (substantia gelatinosa). These distribution patterns indicated that SSEA-1 is present on migratory and/or postmigratory cells. In addition, SSEA-1 is associated with small-diameter dorsal root fibres, the C fibres and A(sigma) fibres, that terminate within the substantia gelatinosa. After birth, SSEA-1 was present throughout the dorsal horn, probably as a result of the myelination of the fibres.

Animals↗
PubMed1992

A simple electronic device for time-lapse recording of neural and other cell movements using a home video cassette recorder.

This article describes a simple electronic unit to obtain time-lapse recordings with the use of a common remote-controlled home video cassette recorder, for example a VHS recorder. The electronic unit is a timer to be connected to the remote-control unit. The video cassette recorder itself remains unchanged. Replay of the recorded images speeds up the original process by a factor of 2-100 x or more. This technique has been applied in video micrographic studies of (1) the development of dorsal root ganglion (DRG) cells in culture, including growth cone and Schwann cell movements, and (2) tumor cell killing by natural killer (NK) cells.

Animals↗
PubMed1992

Open fetal spinal cord surgery in rats with low mortality achieved by prevention of oligohydramnios.

Myelotomies were performed with an open microsurgical technique in rat fetuses aged between E16 and E18. In 87 consecutively treated fetuses the net surgical mortality was as low as 7%. The cause of death due to fetal surgery is shown to be amniotic fluid loss. The high survival rate is attributed to the prevention of oligohydramnios. The technique is described in detail and the results are discussed.

Animals↗
PubMed1992

The magnetic field.

Explore the source record for details and available documents.

Electromagnetic Fields↗
PubMed1991

Prenatal descent of rubrospinal fibers through the spinal cord of the rat.

This study is the first description of the descent of rubrospinal fibers through the spinal cord of the rat fetus. Either horseradish peroxidase or wheat germ agglutinin-horseradish peroxidase conjugate was injected into the spinal cord, at different levels and at different gestational ages. At embryonic day 17 (E17) fibers from all subdivisions of the nucleus ruber (NR) started their descent towards the spinal cord. At E18 fibers from the ventrolateral NR reached the lower cervical spinal cord, and those from the caudal NR reached the lower thoracic spinal cord. At E19 fibers from the dorsomedial NR and from the parvicellular NR had just reached the cervical spinal cord, while fibers from the ventrolateral and caudal NR descended to lower thoracic levels. At E21 fibers from the dorsomedial NR reached the lower cervical spinal cord. Fibers from the ventrolateral and caudal NR completed their descent through the lumbosacral spinal cord during the first three postnatal days. During their descent the rubrospinal fibers were confined to the white matter of the spinal cord. The earliest descending fibers originated in the caudal NR. Fibers from the caudal part of each magnocellular subdivision of the NR descended before their rostral counterparts. Fibers from the dorsomedial NR only reached the cervical enlargement as the fibers from the ventrolateral NR descended through the cervical enlargement. The somatotopy of the adult rubrospinal projection reflects this sequence; the dorsomedial NR (dmNR) projects to the cervical spinal cord, and the ventrolateral NR (vlNR) projects to the lumbosacral spinal cord. In general, early descending fibers originated from neurons located caudally and ventrolaterally, while later descending fibers originated from neurons located progressively more rostrally and dorsomedially in the magnocellular NR.

Animals↗
PubMed1991

Development of projections of primary afferent fibers from the hindlimb to the gracile nucleus: a WGA-HRP study in the rat.

The projection of primary afferent fibers to the gracile nucleus was studied during development. Injections of wheat germ agglutinin-horseradish peroxidase were made into the hindlimb of fetal, postnatal and adult rats. In most cases the sections were alternately stained for wheat germ agglutinin-horseradish peroxidase including counter stain with Neutral red and for acetylcholinesterase. At embryonic day 17 labelled fibers could be traced to the mid-cervical spinal cord but not further rostrally. At embryonic days E18 and E19 labelled fibers penetrate the rostral pole of the nucleus, which does not happen more caudally. At embryonic day E21 the caudal-most pole of the gracile nucleus still is not penetrated by labelled fibers. From postnatal day 1 onwards labelled fibers are found throughout the entire rostrocaudal extent of the gracile nucleus. These results suggest that primary afferent fibers from the hindlimb first grow to the rostral pole of the gracile nucleus and penetrate the rostral pole immediately upon their arrival. During further development more caudal parts of the gracile nucleus are gradually penetrated in a rostrocaudal fashion by primary afferent fibers of the hindlimb.

Afferent Pathways↗
PubMed1991

ELISA incubation times can be reduced by 2.45-GHz microwaves.

The ELISA (Enzyme Linked Immuno Sorbent Assay) technique is widely applied in the field of immunology. The use of this technique implies several incubation periods, often requiring more than one hour each. Microwave irradiation is known to be very useful in accelerating different kinds of processes. This knowledge has led to the present study in which it is proved that 2.45-GHz microwaves are able to reduce ELISA incubation times. This time reduction of 50% or more concerns each of the four incubation steps of the specific indirect ELISA which is used to determine the amount of antibodies in NF90-hybridoma cell culture supernatants. These incubation steps involve the coating of the microtiter plate, the incubation with BSA against non-specific binding, and the incubations with the first and second antibody. Combinations of more microwave-influenced steps in one ELISA save a considerable amount of time. When in addition air is blown through the incubation fluid during microwaving, the extinction values are almost the same as those of conventionally performed ELISAs. Thus, a good match of power setting and irradiation time results in a total incubation time reduction from 5.5 hours to 2 hours in this particular ELISA. Carefully monitoring the temperature of the incubation fluids during irradiation with the use of a fiberoptic thermometer appeared to be of crucial importance in the development of an optimal procedure.

Enzyme-Linked Immunosorbent Assay↗
PubMed1991

Expression of vimentin and glial fibrillary acidic protein in the developing rat spinal cord: an immunocytochemical study of the spinal cord glial system.

The glial system in the developing rat spinal cord was studied using immunocytochemistry. Antibodies to vimentin and glial fibrillary acidic protein (GFAP) were used. At E11, vimentin was first found in the membrana limitans externa. In the matrix layer, short vimentin protrusions were found near the membrana limitans externa at E12. In addition, vimentin was scattered throughout the matrix layer, where it was also present as vimentin-positive tangles. Later in development, vimentin immunoreactivity was distributed in a distinct radial pattern in the matrix layer. During the first postnatal weeks, vimentin was replaced by GFAP which is therefore expressed in a similar radial pattern. This orderly structural organisation of vimentin and GFAP in the matrix layer could indicate the involvement of both proteins in morphogenetic processes such as neuron migration and cell organisation. In the mantle layer, a distinct radial vimentin immunoreactivity was replaced by GFAP immunoreactivity during the first 2 postnatal weeks. In addition, GFAP fibres appeared first, at E18, in the ventral mantle layer associated with the motor neuron columns. These glial fibres originated from a local source. In the dorsal mantle layer, GFAP-positive fibres were oriented tangentially, which is different from the overall radial arrangement. This expression pattern may be related to the ingrowth of primary afferents. In the ventral and dorsal raphe, a major vimentin expression was replaced by a minor presence of GFAP. Within the white matter, a vimentin-positive radial pattern was demonstrated which, after birth, was replaced by GFAP. This palisading pattern suggested an involvement of both proteins in the development and guidance of the ascending and descending spinal cord fibre systems. The general transition from the expression of vimentin to the expression of GFAP in the rat spinal cord takes place during the first 3 postnatal weeks.

Animals↗