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Biomedical subjects

R Pujol

Publications and source records attributed to R Pujol.

At least 181 records · Page 10Linked to original sources
PubMed1984

Incidence and clinical significance of anti-ENA antibodies in systemic lupus erythematosus. Estimation by counterimmunoelectrophoresis.

Eighty-two patients with systemic lupus erythematosus (SLE) were investigated for the presence and significance of serum antibodies to Extractable Nuclear Antigen (ENA) and its major components, RNP, Sm and SS-B (or Ha). The counterimmunoelectrophoresis assay allowed independent detection and measurement of antibodies to the different components. Forty patients had anti-ENA antibodies, 25 (30%) were of anti-RNP type alone or anti-RNP associated with anti-Sm, and 12 (15%) were of anti-RNP type alone. Anti-ENA antibodies distinguished a subset of patients with less common incidence of renal disease, positive Coombs test, anticoagulant serum factors and high titres of anti-DNAds antibodies, with higher incidence of Raynaud's phenomenon, swollen hands, hypergammaglobulinemia and high titres of antinuclear antibodies with speckled pattern on immunofluorescence. SLE patients with anti-RNP antibodies had in addition a high frequency of normal complement values. All but one SLE patient with only anti-RNP antibodies fulfilled at least four or more criteria for the diagnosis of SLE. We conclude that anti-ENA antibodies in SLE patients are associated with a low prevalence of nephritis and a clinical and laboratory profile similar to that of the MCTD syndrome. These findings demonstrate the difficulty of inferring rigid differences between MCTD and SLE. The MCTD syndrome probably represents only one segment of the whole clinical spectrum of SLE.

Antibodies, Antinuclear↗
PubMed1983

The pattern of sensorineural degeneration in the cochlea of the deaf shaker-1 mouse: ultrastructural observations.

Experiments were done to extend existing knowledge on the nature and course of postnatal sensory and neural changes in the inner ear of shaker-1 mutant mice. Mice, 3-, 6-, 10-, 12-, 18-, and 30 days old, homozygous for the sh-1 gene, were studied using transmission electron microscopy. The data indicate retarded development coupled with the early onset of progressive degeneration in Corti's organ its nerve supply, and the cells of the spiral ganglion. Especially noteworthy are the following: in 3-day-old mice both outer hair cells and spiral ganglion cells are already abnormal. The latter are especially loosely ensheathed by glial cells and are in direct contact with nerve fibers. Outer hair cells contain vacuoles and lysosomes. By 6 days of age inner hair cells come to be similarly affected. By 18 days most of the afferent nerve supply of the organ of Corti has degenerated. The behavior of efferents within the organ is complex. Efferents arrive late (day 12) at the outer hair cells, they are few in number, form only immature synapses with the cell, and they subsequently degenerate. In contrast, the efferent nerve supply of the inner hair cell appears normal, if not over-abundant. The simultaneous occurrence of organ of Corti and spiral ganglion cell anomalies is discussed in terms of the role of sensorineural interactions in the expression of genetic defects affecting the inner ear. The selective degeneration of efferents to outer hair cells is viewed as being consistent with the hypothesis that there are two independent efferent systems which innervate the two types of cochlear sensory hair cells.

Animals↗
PubMed1983

Cochlear synaptogenesis in the hypothyroid rat.

The effects of congenital hypothyroidism on cochlear synaptogenesis were studied using transmission electron microscopy in 30 propylthiouracil-treated rat pups 1-35 days of age. No difference with controls was observed at the level of the inner hair cells which are known to mature essentially during the prenatal period. On the contrary, hypothyroidism resulted in numerous abnormalities in synaptogenesis at the level of the outer hair cells: abnormal persistence of numerous afferent dendrites and presynaptic specializations, incomplete development of efferent terminals and absence of formation of postsynaptic cisterns. It can be concluded that hypothyroidism results in severe retardation in the postnatal development of the innervation of outer hair cells.

Animals↗
PubMed1983

Early degeneration of sensory and ganglion cells in the inner ear of mice with uncomplicated genetic deafness (dn): preliminary observations.

Deafness (dn/dn) mouse cochlea was investigated by electron microscopy in order to detect the first postnatal signs of histopathology. At birth, the inner hair cells (IHCs) showed abnormal vacuolization, afferent dendrites at IHC level appeared swollen and devoid of cytoplasmic content, and most of the neurons of the spiral ganglion contained an abnormal smooth endoplasmic. At day 7, these abnormalities had greatly increased, especially in the spiral ganglion neurons where large patches of filamentous material were found. These observations can account for the permanent electrophysiological deafness of dn/dn mice. Moreover, these data, showing early cytological abnormalities in both the IHCs and the spiral ganglion neurons, indicate that it is difficult to simply classify the deafness mutation as being 'degenerative'; some 'morphogenetic' processes are likely also involved.

Animals↗
PubMed1983

[Ultrastructural localization of immune reactions to met-enkephalin antibodies in the organ of Corti].

Using a pre-embedding immunoperoxidase technique, enkephalin-like substances were described, at the ultrastructural level, in efferent terminals of the guinea pig cochlea. These fibers were located in the inner spiral bundle and the tunnel spiral bundle. No immunoreaction was detected under the outer hair cells. Most of the immunoreactive fibers contacted afferent dendrites; synaptic differentiations were seen, suggesting a possible inhibitory effect of the enkephalin immunoreactive efferents upon the auditory afferents.

Animals↗
PubMed1982

Sectioning the efferent bundle decreases cochlear frequency selectivity.

Cochlear frequency selectivity was tested in rats and cats before and after sectioning the vestibular nerve which carries the efferent bundle to the cochlea. Compound action potential tuning curve were obtained by a simultaneous masking procedure. Transection of the efferent bundle resulted, in all group of animals, in an enlargement of the tip segment of the tuning curve. The Q10 dB value decreased by about 30% without any significant threshold change. These results taken together with previous developmental findings, suggest that efferents to outer hair cells could play a role in sharpening the frequency selectivity of the cochlea.

Animals↗
PubMed1981

Age-related changes in the C57BL/6J mouse cochlea. I. Physiological findings.

The development and degeneration of cochlear output was studied in C57BL/6J mice from the time of hearing onset (12 days of age) through adulthood (50 days of age) using the eighth nerve compound action potential (N1). Mice were stimulated in free-field, using short rise-time tone bursts (2-35 kHz). Sensitivity to tones and threshold tuning curve sharpness (Q10) increased markedly between 12 and 20 days of age. Response latencies changed, in a complex way, to attain minimum values by 20 days of age. The form of intensity function was essentially identical in 12- and 16-day-old mice. In 30- and 40-day-old mice signs of both hearing development and degeneration were seen. For example, while N1 threshold intensities to low-frequency tones continued to decline, those to high frequencies began to increase. The results indicate that some of the previously observed age-related changes in central auditory function in C57BL/6J mice can be accounted for in terms of cochlear evolution. The observed changed in cochlear function are discussed in relation to outer-, middle-, and inner-ear modifications. A basis for the limits of the critical period for audiogenic seizure "priming' is hypothesized.

Aging↗
PubMed1981

Age-related changes in the C57BL/6J mouse cochlea. II. Ultrastructural findings.

The C57BL/6J mouse organ of Corti was studied using transmission electron microscopy. The basal coil of the cochlea was examined in mice 1-50 days of age. At birth the cochlea was very immature but both types of hair cells were innervated. Inner hair cells (IHC) were connected to afferent and efferent processes, and efferent endings synapsed on IHC afferents. Outer hair cells (OHC) were innervated exclusively by afferents, which made well-defined synapses with the cell. Maturation at IHC took place rapidly and was essentially over by about 12 days of age. Changes were largely restricted to an increase in presynaptic specializations opposite afferents and a decrease in postsynaptic specializations (cisterns) opposite efferents. Ontogeny at OHC took place over a longer, 2.5 week, period. Afferent synapses lost their presynaptic specializations (synaptic bodies), and then efferent fibers arrived below OHC. The efferents subsequently made temporary axo-dendritic synapses with the afferents before replacing most of them at OHC. The first synapses between efferent endings and OHC were seen at 9 days of age, but it was not until about 20 days of age that mature synapses were seen. Some evidence of hair cell degeneration was seen in 30- and 50-day-old mice. The results are discussed in terms of sensory hair cell differentiation, the disappearance of OHC synaptic bodies, and age-related changes in auditory system function.

Aging↗
PubMed1981

Variability of the hereditary deafness in the white cat. I. Physiology.

Electrophysiological investigations, at different levels of the auditory pathway, were performed on 54 white cats. Hearing tests generally consisted of recording electrocochleograms or making audiograms from collicular or cortical responses. Some investigations were performed with chronically implanted electrodes to detect the first appearance of a hearing defect. Results showed no evident relationship between the age of the white cat and the appearance, severity or completeness of hearing loss. A large variety of hearing remnants was encountered in partly deaf animals which is tentatively related to a similar variety of histological damage of the cochlea described in a companion paper (Rebillard, M., Pujol, R. and Rebillard, G. (1981): Hearing Res. 5, 189-200).

Age Factors↗
PubMed1981

Variability of the hereditary deafness in the white cat. II. Histology.

Cochlear degeneration in white cats was investigated by light- and electron-microscopic examinations. A great variety of histological damage was encountered both in completely and partially deaf animals. These variable features are discussed mainly with regard to the rate of degeneration and the site of the first damage. Atypical findings, such as primary degeneration of spiral ganglion neurons, are presented. The possibility for some damaged cochleas to work without hair cells is described. These results clearly demonstrate that hereditary degeneration in the cochlea of white cats is not a unique and regular process.

Animals↗
PubMed1981

High resolution radioautographic study of the inner ear following in vivo tritiated deoxyglucose administration.

Light and high resolution radioautography were performed on cat and guinea pig inner ear after an in vivo administration of tritiated deoxyglucose and conventional histological treatments. In the guinea pig cochlea a diffuse radioautographic reaction product appeared on all the neurosensory and surrounding structures, with a more intense labelling of stria vascularis and Reissner's membrane. In the cat vestibular organ a diffuse reaction was also noted, with an intense clear-cut labelling of some dark cells at the base of the lateral crista and on some cells limiting the endolymphatic space, opposite the utricular macula. At the EM level, the silver grain distribution preferentially appeared to be localized on the cytoplasmic glycogen granules. In addition, some sensory cells were densely marked, the silver grains neither occurring on the nucleus nor on the surrounding nerve calyx, and rarely upon the mitochondria. These data indicate that using classical histological treatments, it is possible to retain a part of the radioactive molecules around the injection site. The possible physiological meaning of the selective labeling of some cellular and subcellular compartments is discussed.

Animals↗
PubMed1980

[Cellular detection of the in vivo incorporation of tritiated 2-deoxyglucose. Radioautographic study in the inner ear].

Inner ear injection of (3H) deoxyglucose was followed by in situ glutaraldehyde fixation and, after removal, by traditional preparation of the tissue for electron microscopy. Radioautography of semi-thin sections revealed preferential tracer accumulation in metabolically active structures such as the cochlear stria vascularis and the dark cells surrounding the basis of the vestibular cristae. Furthermore, in the vestibule, the perikaryon of some sensory cells was intensely labelled. These results show that an in vivo injection of deoxyglucose, followed by conventional histological processing can be used to mark active cells at both cellular and subcellular levels.

Animals↗
PubMed1980

Cochlear receptor development in the rat with emphasis on synaptogenesis.

Maturation of the albino rat cochlea was studied using light and electron microscopy. Critical stages of receptor morphology were examined. At birth, cochlear structures are very immature, but even at this early stage synapses are recognizable. Under inner hair cells (IHCs) both afferent and efferent synapses are present. Under outer hair cells (OHCs) only afferent endings are seen. During the first postnatal week, synaptic development proceeds slowly. Between 6 to 12 days of age, substantial changes occur in the pattern of hair cell innervation. There are fewer efferent synapses at the IHC level and the first efferent junctions form on OHCs. In addition, a pattern of temporary innervation is seen under the OHC, with axo-dendritic synapses between efferent endings and afferent fibres. Between 12 and 16 days of age the main changes in hair cell innervation are at OHC level where afferent junctions regress and large efferent synapses form. By 16 days of age sensory-neural relationships seem adult-like. The results are discussed in relation to rat cochlear electrophysiological development and the period of supra-normal sensitivity to acoustic trauma.

Age Factors↗