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Biomedical subjects

R Pujol

Publications and source records attributed to R Pujol.

232 records · Page 13Linked to original sources
PubMedDate not supplied

Mortality and morbidity in nonagenarian patients following hip fracture surgery.

BACKGROUND: The number of people living more than 90 years is increasing, and this population shows a high incidence of hip fractures. OBJECTIVE: To study prospectively the mortality and morbidity following hip fracture surgery in nonagenarian patients. METHODS AND SUBJECTS: 106 nonagenarian patients were admitted for femoral neck fracture and treated surgically in the traumatology and geriatric departments of two university hospitals. All patients received comprehensive geriatric assessment. 75 patients were followed up after a 3-month control period. Mortality and functional status were assessed using the Barthel index (BI) and mobility, dependency on walking aids, residential status, and degree of residual pain were the items assessed for morbidity. RESULTS: In-hospital mortality was 10%; the 3-month accumulate mortality was 20%. The mean BI of the 75 patients who survived was 53 showing a persistent decrease compared with their BI previous to the hip fracture (79; p < 0.003). The decline in BI after 3 months persisted in 91% of patients. Before injury, 11% patients were housebound, while 45% were housebound 3 months later. 54% were independent before the fracture occurred, and only 16% 3 months later. Only 12% of patients who survived were unable to return to their pre-admission dwelling. CONCLUSIONS: Findings of low perioperative mortality and acceptable morbidity support the view that surgery followed by rehabilitation is indicated in selected nonagenarian patients.

Aged↗
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Histo-physiological relationships in the deaf white cat auditory system.

An investigation is underway in deaf white cats in order to clear up some problems about the timing of cochlear degeneration, the relationships between physiological and histological findings, and the consequential state of central auditory pathways. The first results reported here show that degeneration of sensory structures was much more advanced than physiological results lead us to believe. The possibility of direct fibre stimulation is discussed. Although degeneration of nervous structures was delayed compared with sensory ones, some early abnormalities in myelination were found. In the adult, completely deaf for years, the electrical stimulation of cochlear nuclei evoked normal-looking field responses at the cortical level. Thus some degree of auditory pathway functional integrity appeared even long after they were disconnected from receptors.

Animals↗
PubMedDate not supplied

Development of the labyrinthine receptors in the guinea pig, cat and dog.

Light and electron microscope observations were made on the vestibular receptors in fetal guinea pigs and cats, and in kittens and puppies. In the guinea pig hair cells were recognizable by 30 DBB (days before birth), myelinated preganglionary nerve fibers by 25 DBB, and neuro-epithelial synapses by 15 DBB. These observations can be correlated with the early development of the righting reflex in fetal guinea pig. Similar ultrastructural observations were made on cats and dogs at different times in development. A direct comparison between development in the vestibular system and the auditory system is possible since development of the organ of Corti in the same animals has previously been documented.

Age Factors↗
PubMedDate not supplied

Primary neural disorders in the deaf white cat cochlea.

Eleven white kittens were investigated from 2 days after birth up to an age of 4 months. After their hearing ability or deafness had been tested electrophysiologically, electron microscopic work was done at the level of the cochlea. Previous histological data indicated that the hereditary process of degeneration begins at the epithelial and sensory elements of the cochlea, and that the neural degeneration is only a secondary and very slow process. Results presented here indicate that, at least in some white cats, this assumption needs to be modified. Early failure in the myelination of the lamina spiralis fibres was noticed in most of the white kittens. Furthermore, two kittens (7 and 16 days old) presented a complete degeneration of the spiral ganglion neurons, and signs of anterograde degeneration of their fibres going to the organ of Corti. These primary neural defects indicate that hereditary hearing defects may directly affect both epithelio-sensory and neural structures.

Albinism↗
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Sensitive period to acoustic trauma in the rat pup cochlea. Histological findings.

In a previous paper we demonstrated physiologically a sensitive period for acoustic trauma in the rat pup cochlea, with a maximum at 22 days of age. Seven or 60 days after noise exposure these 22-day exposed rats were used for light and electron microscopy. At 7 days, surface preparation revealed restricted damage to the basal cochlear coil, while with electron microscopy signs of cytoplasmic degeneration appeared in the great majority of basal coil structures. Two months after noise exposure these structures have completely degenerated. These results were discussed in terms of mechanical versus metabolic explanations of the critical period for acoustic trauma.

Animals↗
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Innervation of the chicken basilar papilla during its development.

Afferent and efferent innervation of the chicken basilar papilla was studied during development. Observations from the 10-day embryonic stage (E 10) and the 8-day post-hatch (P 8), were focussed on some characteristic features of the synaptogenesis. The presynaptic specializations (synaptic bodies: SB) appear early (E 10) in hair cells, opposite afferent dendrites. They are found at all developmental stages in tall hair cells (THC), whereas they become rare in short hair cells (SHC). The maturation of afferent endings, especially those connected to THC, is characterized around the E 15 stage, by an over abundant sprouting and branching. The development of the efferent system indicates two stages. Starting at E 14, some small efferent synapses are seen at the base of the THC and SHC. From E 18, the large synapses extend to the base of SHC. These results are discussed in the light of homologies with the mammalian inner and outer cochlear hair cells.

Animals↗
PubMedDate not supplied

Radioautographic study of the symphathetic fibers in the cochlea.

The noradrenergic fibers of the cochlea have been investigated by radioautography after an in vitro labeling by 3H-Noradrenalin (3H-NA). Unmyelinated, perivascular and non-perivascular fibers took up and retained 3H-NA. Non-perivascular fibers formed small bundles together with unmyelinated efferents in the intraganglionic spiral bundle and the osseous spiral lamina. No labeled fibers were detectable beyond the habenula inside the organ of Corti. The labeled fibers, which are probably noradrenergic, were characterized by numerous varicosities and discontinuous Schwann sheathes. These morphological characteristics could associate them with a general role in cochlear function. Sometimes, labeled fibers were also found very close to Ranvier's node of certain myelinated fibers, which could suggest a specific effect on these fibers.

Adrenergic Fibers↗
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The Gunn rat: an experimental model for central deafness.

The Gunn rat which develops neonatal hyperbilirubinemia has been used as an experimental model to evaluate the effect of bilirubin on the auditory system. Electrocochleographic and morphological studies (including light microscopy, surface preparations and transmission electron microscopy) did not reveal any cochlear abnormality in homozygous Gunn rats. Brainstem auditory evoked potentials showed morphological and amplitude changes suggesting a functional damage in the brainstem auditory pathways. These results suggest that hearing loss, when observed in kernicterus, is primarily due to neuronal damage at the level of brainstem auditory nuclei.

Animals↗
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Hair cell innervation in the fetal human cochlea.

Twelve cochleas from human fetuses ranging in age from 13 to 22 gestational weeks were investigated by transmission electron microscopy in order to follow the development of hair cell innervation. First, we were able to confirm the two general gradients of cochlear maturation, i.e. 'internal-to-external' and 'base-to-apex'. In the 14th week of gestation, the inner hair cell pattern of innervation was almost mature, with well formed afferent synapses and axo-dendritic efferent contacts. At the outer hair cell level, only afferents, probably both spiral and radial ones, were present up to week 16. At week 22, axo-somatic synapses were observed between the medial efferents and the outer hair cells, but they were not yet completely mature. At this stage the myelination had begun within the spiral lamina fibres. These findings confirmed that the different stages of synaptogenesis in the human cochlea are similar to that described in other mammals, and thus the same kind of functional relationships could be proposed.

Cochlea↗
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Evoked oto-acoustic emissions from adults and infants: clinical applications.

Evoked oto-acoustic emissions (EOAEs), i.e. sounds emitted by the cochlea in response to a click, are recordable in the ear canal by a miniature microphone. They reflect an active cochlear biomechanism based upon OHC function, which accounts for the exquisite properties of sensitivity and frequency selectivity of the cochlea. EOAE recordings can therefore be considered an objective, easy, rapid and non-invasive audiological procedure which can be used to investigate the most sensitive part of the cochlea. From our experience of more than 300 recordings, we propose several clinical applications of EOAEs: 1) objective assessment of sensorineural hearing loss; 2) staging Meniere's disease by recording glycerol-induced changes; 3) diagnosis of retrocochlear pathology, and 4) screening of auditory function in infants.

Acoustic Stimulation↗
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Lateral and medial efferents: a double neurochemical mechanism to protect and regulate inner and outer hair cell function in the cochlea.

In the mammalian cochlea, the two types of hair cells drastically differ in their anatomy and physiology. Each system receives a specific efferent control originating in the brainstem superior olivary complex. Inner hair cells are connected to the afferent type I ganglion neurons (comprising 95% of the auditory nerve) which postsynaptically receive the input of the lateral efferents. On the other hand, outer hair cells, whose electromotile properties are responsible for the active mechanism, are directly under medial efferent control. Neurochemically, both types of efferents are also well distinguished. The present paper reviews the efferent neurochemistry and pharmacology, with an emphasis on the protective roles of each system on cochlear function. The role of lateral efferent neurotransmitters such as enkephalins and dopamine in protecting the auditory nerve dendrites against excessive noise and/or excitotoxicity is especially addressed. The cholinergic medial efferents synapsing with the outer hair cells play a role in altering and/or modulating cochlear micromechanics. They could also be involved in a potentiating effect on aminoglycoside ototoxicity.

Acetylcholine↗
PubMedDate not supplied

Clinicopathological correlations and prognostic factors in lupus nephritis.

OBJECTIVE: To define prognostic factors at the moment of the diagnosis in lupus nephritis, and to assess the contribution of renal histologic data. PATIENTS AND METHODS: Sixty-two patients with systemic lupus erythematosus (SLE) and histologic evidence of nephritis were studied for renal outcome. Correlations between clinical or biological and histological data were carried out as an indicator of the utility of the renal biopsy. RESULTS: There were no significant differences in creatinine between the different histologic classes at the moment of the diagnosis, although the WHO classification correlated well with proteinuria and immunologic activity. There was a strong correlation between clinical and histological activity as measured by the activity index in proliferative glomerulonephritis, mainly with creatinine and proteinuria, but not with haematuria or immunological activity. Young age at the time of renal biopsy, proliferative classes III and IV, and the chronicity index were associated with a poorer renal prognosis. CONCLUSIONS: High immunologic activity, mainly elevated anti-DNA titers and decreased levels of CH100, is highly suggestive of proliferative glomerulonephritis. Proliferative classes III and IV and high chronicity indexes are associated with a worse prognosis in lupus nephritis.

Adolescent↗