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Biomedical subjects

H Felix

Publications and source records attributed to H Felix.

At least 55 records · Page 3Linked to original sources
PubMed1987

Intracranial facial nerve anastomosis.

A technique of intracranial facial nerve anastomosis using fenestrated collagen splints was used in eight patients operated upon for acoustic neuroma or glomus temporale tumor. This technique is rapid and simpler than suturing in the cerebellopontine angle. Clinical results are as good as or even better than those obtained with more peripheral facial nerve anastomosis or grafting. An animal study demonstrated no undue histologic reaction to the collagen splints.

Animals↗
PubMed1987

Surgical anatomy of the rat facial nerve.

Animal models of facial nerve healing and regeneration are becoming increasingly important as new techniques of facial nerve repair and grafting are developed. We have described in detail the peripheral branching pattern of the rat facial nerve and performed axon counts on the main trunk and peripheral branches. Similarities and differences between the human and rat facial nerve are emphasized and the branches of the rat nerve amenable to experimental manipulation are identified. In addition, electrophysiologic data from the rat show a more diffuse pattern of innervation of the face from the individual branches than seen in humans.

Action Potentials↗
PubMed1986

Biological studies of ten human squamous carcinoma cell lines: an overview.

Ten cell lines established from surgical specimens of human squamous carcinomas of the tongue and larynx have been investigated with respect to their motility, ultrastructure, karyotypes, certain biochemical features, interaction with normal epithelial and stromal elements and capacity to infiltrate three-dimensional organoid systems. All the cell lines have maintained several morphological and biochemical characteristics indicating a common origin, although the extent to which each line displays this heritage is variable. The phenotypes of each of the individual cell lines are, however, notably stable. Data are provided for epithelial surface markers (including epidermal growth factor, EGF) and for the synthesis and release of prostaglandins and proteases which may be involved in invasive mechanisms. Encounters between the cell lines and organoid substrata (embryonic chick heart spheroids, human amnion, chick chorioallantoic membrane) are described: the results indicate a scale of invasiveness ranging from lack of penetration to full-thickness infiltration by cells showing various distinctive growth patterns. Correlation between in vitro and in vivo findings is discussed, and it is suggested that the biological heterogeneity of the lines may reflect inherent properties of the original carcinoma cell populations which are more distinctly expressed in vitro.

Aged↗
PubMed1986

The cavitron ultrasonic surgical aspirator system. An anatomical and physiological study of the effect of its use on the rat facial nerve.

The Cavitron Ultrasonic Surgical Aspirator System was used to clear the facial nerve from adjacent tissues in the rat. Acute damage to the nerve was manifest electrophysiologically by a significant decrease in amplitude of the conducted nerve action potential (P less than 0.0001) and increase in latency of the muscle action potential (P less than 0.01). Impairment of neural activity was temporary. In the majority of rats facial movements and neural activity returned to their preoperative state within 14 days. The nerves were prepared for light and transmission electron microscopy. The histopathological correlate of the documented functional impairment was disruption of the perineurium and a variable degeneration of the nerve fibres. Regeneration was evident by the end of the second postoperative week, but degenerative changes seen in some of these new fibres cast doubt on their viability.

Action Potentials↗
PubMed1985

Histopathological features of the spiral ganglion and cochlear nerve in temporal bones from three patients with profound hearing loss.

In the following study the condition of the spiral ganglion and the cochlear nerve of ears from patients suffering from profound hearing loss is described. The number of spiral ganglion cells has been related to the clinical diagnosis. The number of spiral ganglion cells in the two temporal bones of a patient with Neomycin ototoxicity was almost normal. A reduction of less than one-third of spiral ganglion cells has been observed in the temporal bones of a child who died after a bacterial labyrinthitis. The temporal bone with a Mondini dysplasia revealed a pronounced reduction of ganglion cells of more than two-thirds. The cochlear nerve trunk in the internal auditory canal appeared normal in all three cases. The present findings are discussed in respect to the degenerative behaviour of the cochlear neural elements in human being compared to animals.

Aged↗
PubMed1985

Light and electron microscopic investigation of cochlear nerve specimens from profoundly deaf patients.

Surgical specimens of cochlear nerves from patients suffering from sudden deafness or congenital deafness have been evaluated with regard to the number of nerve fibres and the morphological appearance. The meatal segment of cochlear nerves from 6 patients with sudden deafness shows a variable number of nerve fibres and different morphological changes. The duration of deafness does not correlate with the number of nerve fibres. In the case of congenital deafness for more than 17 years the cochlear nerve presented an apparently normal number of myelinated fibres. The presented study reveals that the retrograde degeneration of the human cochlear nerve is unpredictable.

Adolescent↗
PubMed1984

Morphologic aspects of the leading lamella in locomotive normal and neoplastic blood cells. A study by scanning electron microscopy (SEM).

A leading lamella is part of every translocative cell, irrespective of nature and origin. The morphological aspect of this cytoplasmic extension, however, varies and, among the different cell types, locomotive blood cells show the greatest diversity with regard to position, size and shape. In this communication, SE micrographs of benign and malignant blood cells of different classes are presented. The dynamic interpretation attempted for the description of the static photographs is based on analyses of time-lapse films which show the activities of the live cells.

Animals↗
PubMed1982

[Mefloquine in the treatment and prevention of malaria ].

Mefloquine (WR 142,490 or Ro 21,5998) is a new antimalarial drug, 4-quinoline methanol derivative, with a prolonged half-life in man and a good activity against multidrug resistant P. falciparum strains. Tolerance and pharmacokinetic evaluated in 8 black African subjects, is according to previously studies in American or Asian patients: the mean whole blood half-life is 15,6 days. Efficiency of various regimens (1 g in 3 days; 1,50 g in 3 intakes, one day; 25 mg per kg in one intake) was studied on 39 patients, infected by african strains of P falciparum in 26 cases. Fever and parasitemia disappeared within 3 days in all cases. Sera from these patients showed a complete inhibition of P. falciparum continuous culture on day 30 at least. The use of mefloquine may be actually reserved for area where resistant strains of P. falciparum are widespread. In African this use, in theory possible, is not warrant.

Adolescent↗
PubMed1982

Shape and motility, two interdependent features.

By the concurrent use of scanning electron microscopy (SEM) and time lapse cinematography the interdependence of cellular shape and motility was visualized for leukemia cells and for normal and malignant epithelial cells. During the different modes of motility (stationary without net translocation of the whole cell, and locomotion), the cells display a distinct configuration. This allows the interpretation of static images in terms usually reserved for the description of activities of living cells. The ability of cells to change shape is of special importance when they migrate in the body. Irrespective of nature and origin, these cells must continuously adapt their configuration to the structural elements which they encounter in their pathways. The existence of such an adaptability could be shown by time lapse films for leukemia cells and for cells of the V2 rabbit carcinoma moving in mesenteries of rat and rabbit, respectively.

Carcinoma, Squamous Cell↗
PubMed1982

Interactions of tumor cells with human amnion membrane: a model for studying tumor invasion in vitro.

The human amnion membrane consisting of a single layer of epithelium attached to the continuous basement membrane and the underlying collagenous stroma has been used to study tumor invasion in vitro by means of electron microscopy. Three cell lines utilized in these experiments were established from surgical specimens of human squamous cell carcinomas of the tongue and larynx. The cultivation of amnion membrane for 48h or longer leads to some alterations in the morphological appearance. All three carcinomas form aggregates which appear firmly attached to the amnion epithelium and are able to establish contacts to the basement membrane within 96h. In two cases the basement membrane reveals local defects and some cells have extended processes into the collagenous tissue. However, none of the tumor cells of the three carcinomas have broken through the basement membrane and grown into the collagenous stroma. Some differences of interaction between amnion epithelial cells and tumor cells of the three carcinomas are apparent. These ultrastructural findings show, that the amnion membrane model allows morphological analysis of various steps of tumor invasion under standardized conditions.

Amnion↗
PubMed1981

Imported malaria in a hospital in Paris.

The number of cases of imported malaria diagnosed by the Parasitology Laboratory of the Pitié-Salpêtrière Hospital Group in Paris has shown a significant increase in recent years. From 1970 to 1979, 443 cases were diagnosed and the annual number recorded during this period rose from seven to 93 cases. This is causing anxiety since Plasmodium falciparum is the principal species observed, affecting two out of three patients. The principal epidemiological characters of malaria imported into France, the diagnostic difficulties and the therapeutic schedules are shown in a study of 192 case histories of patients observed by the authors.

Adolescent↗